Urine mercury levels correlate with DNA methylation of imprinting gene H19 in the sperm of reproductive-aged men.
Lu Zhaoxu,Ma Yufeng,Gao Linying,Li Yingjun,Li Qiang,Qiang Mei
BACKGROUND:Mercury (Hg) is a well-recognized environmental pollutant known by its toxicity of development and neurotoxicity, which results in adverse health outcomes. However, the mechanisms underlying the teratogenic effects of Hg are not well understood. Imprinting genes are emerging regulators for fetal development subjecting to environmental pollutants impacts. In this study, we examined the association between preconceptional Hg exposure and the alteration of DNA methylation of imprinting genes H19, Meg3, and Peg3 in human sperm DNA. METHODS:A total of 616 men, aged from 22 to 59, were recruited from Reproductive Medicine Clinic of Maternal and Child Care Service Center and the Urologic Surgery Clinic of Shanxi Academy of Medical Sciences during April 2015 and March 2016. Demographic information was collected through questionnaires. Urine was collected and urinary Hg concentrations were measured using a fully-automatic double-channel hydride generation atomic fluorescence spectrometer. Methylation of imprinting genes H19, Meg3 and Peg3 of sperm DNA from 242 participants were examined by bisulfite pyrosequencing. Spearman's rank and multivariate regression analysis were used for correlation analysis between sperm DNA methylation status of imprinting genes and urinary Hg levels. RESULTS:The median concentration of Hg for 616 participants was 9.14μg/l (IQR: 5.56-12.52 μg/l; ranging 0.16-71.35μg/l). A total of 42.7% of the participants are beyond normal level for non-occupational exposure according to the criterion of Hg poisoning (≥10 μg/L). Spearman's rank analysis indicated a negative correlation between urinary Hg concentrations and average DNA methylation levels of imprinted genes H19 (rs = -0.346, p <0.05), but there was no such a correlation for Peg3 and Meg3. Further, we analyzed the correlation between methylation level at individual CpG site of H19 and urinary Hg level. The results showed a negative correlation between urinary Hg concentrations and three out of seven CpG sites on H19 DMR, namely CpG2 (rs = -0.137, p <0.05), CpG4 (rs = -0.380, p <0.05) and CpG6 (rs = -0.228, p <0.05). After adjusting age, smoking, drinking, intake of aquatic products and education by multivariate regression analysis, the results have confirmed the correlation as mentioned above. CONCLUSIONS:Mercury non-occupational environmental exposure in reproductive-aged men was associated with altered DNA methylation outcomes at imprinting gene H19 in sperm, implicating the susceptibility of the developing sperm for environmental insults.
Evaluation of vitrification protocol of mouse ovarian tissue by effect of DNA methyltransferase-1 and paternal imprinted growth factor receptor-binding protein 10 on signaling pathways.
He Zhong-Yi,Wang Hong-Yan,Zhou Xue,Liang Xue-Yun,Yan Bei,Wang Rui,Ma Liang-Hong,Wang Yi-Li
Transplantation of cryopreserved ovarian tissue has been considered as a promising way of fertility preservation for women. however, this cryopreservation method is prone to post-resuscitation follicle proliferation and oocyte development stagnation, affecting late transplant survival. To evaluate current vitrification works, we investigated the critical pathway alternations in vitrified-warmed juvenile 10-day-old mouse ovary. We showed a significant decrease of protein kinase B (Akt) and Mitogen-activated protein kinase (Mapk) phosphorylation, during which serine/threonine kinases play central roles in coordinating follicle and oocyte development and stress response. Inhibition of Akt and Mapk activity were associated with one of the imprinted insulin pathway negative regulatory genes, Growth factor receptor-binding protein 10 (Grb10) which remarkably increased in vitrified-warmed juvenile mouse ovary than that of fresh group (p < 0.05). RNAi-induced Grb10 down-regulation reversed the decrease in Akt and Mapk phosphorylation. The increase of Grb10 expression was partially caused by the hyper-methylation of the promoter region, associated with the decrease of follicular DNA methyltransferase (Dnmt) 1 protein in different stages of vitrified-warmed group, compared to fresh group (p < 0.05). The mRNA and protein expression of Dnmt1 in ovary of vitrified-warmed juvenile mouse were remarkably lower than those in fresh group (p < 0.05). Dnmt1 overexpression dramatically reversed Grb10 up-regulation and Akt and Mapk phosphorylation reduction. Taken together, our findings suggest that Grb10 expression might be helpful in evaluation of effectiveness of vitrification, and considered as a potential target for further vitrification protocols improvement in the future.
Loss of imprinting mutations define both distinct and overlapping roles for misexpression of IGF2 and of H19 lncRNA.
Park Ki-Sun,Mitra Apratim,Rahat Beenish,Kim Keekwang,Pfeifer Karl
Nucleic acids research
Imprinted genes occur in discrete clusters that are coordinately regulated by shared DNA elements called Imprinting Control Regions. H19 and Igf2 are linked imprinted genes that play critical roles in development. Loss of imprinting (LOI) at the IGF2/H19 locus on the maternal chromosome is associated with the developmental disorder Beckwith Wiedemann Syndrome (BWS) and with several cancers. Here we use comprehensive genetic and genomic analyses to follow muscle development in a mouse model of BWS to dissect the separate and shared roles for misexpression of Igf2 and H19 in the disease phenotype. We show that LOI results in defects in muscle differentiation and hypertrophy and identify primary downstream targets: Igf2 overexpression results in over-activation of MAPK signaling while loss of H19 lncRNA prevents normal down regulation of p53 activity and therefore results in reduced AKT/mTOR signaling. Moreover, we demonstrate instances where H19 and Igf2 misexpression work separately, cooperatively, and antagonistically to establish the developmental phenotype. This study thus identifies new biochemical roles for the H19 lncRNA and underscores that LOI phenotypes are multigenic so that complex interactions will contribute to disease outcomes.
Transcriptome analysis identifies pathways associated with enhanced maternal performance in QSi5 mice.
Ramanathan Palaniappan,Martin Ian C,Gardiner-Garden Margaret,Thomson Peter C,Taylor Rosanne M,Ormandy Christopher J,Moran Christopher,Williamson Peter
BACKGROUND:Highly fecund mouse strains provide an ideal model to understand the factors affecting maternal performance. The QSi5 inbred strain of mice was selected for high fecundity and low inter-litter interval, and is very successful at weaning large numbers of offspring when compared to other inbred strains. RESULTS:Post-natal pup weight gain was used to estimate mammary gland output and to compare the performance of QSi5 mice to CBA mice. Cumulative litter weights and individual pup weight gain was significantly higher throughout the first eight days of lactation in QSi5 mice compared to CBA mice. Morphometric analysis of mammary glands during pregnancy in QSi5 mice revealed a 150 percent greater ductal side branching compared to CBA mice (P < 0.001). Ontology and pathway classification of transcript profiles from the two strains identified an enrichment of genes involved in a number of pathways, including the MAPK, tight junction, insulin signalling and Wnt signalling. Eleven of these genes, including six genes from the MAPK signalling pathway, were identified as associated with postnatal growth. Further, positive mediators of Wnt signalling, including Wnt4, Csnk2a1 and Smad4, were over-represented in the QSi5 strain profile, while negative regulators, including Dkkl1, Ppp2r1a and Nlk, were under-represented. These findings are consistent with the role of Wnt and MAPK signalling pathway in ductal morphogenesis and lobuloalveolar development suggesting enhanced activity in QSi5 mice. A similar pattern of phenotype concordance was seen amongst 12 genes from the tight junction pathway, but a pattern did not emerge from the insulin signalling genes. Amongst a group of differentially expressed imprinted genes, two maternal imprinted genes that suppress growth induced via the IGF signalling pathway, Grb10 and Igf2r, were under-represented in QSi5 mice. Whereas Peg3 and Plagl1, both paternally imprinted genes that enhance neonatal growth, were over-represented in QSi5 mice. CONCLUSION:We propose that the combined action of at least three major signalling pathways involved in mammary gland development and milk secretion, namely Wnt, MAPK and tight junction pathways, contribute to the superior maternal performance phenotype in QSi5 mice. Additionally, favourable expression patterns of the imprinted genes Peg3, Plagl1, Grb10 and Igf2r may also contribute.
The Differentiation Potency of Trophoblast Stem Cells from Mouse Androgenetic Embryos.
Suzuki Daisuke,Morimoto Hiromu,Yoshimura Kaoru,Kono Tomohiro,Ogawa Hidehiko
Stem cells and development
In mice, trophoblast stem (TS) cells are derived from the polar trophectoderm of blastocysts. TS cells cultured in the presence of fibroblast growth factor 4 (Fgf4) are in an undifferentiated state and express undifferentiated marker genes such as Cdx2. After removing Fgf4 from the culture medium, TS cells drastically reduce the expression of undifferentiated marker genes, stop cell proliferation, and differentiate into all trophoblast cell subtypes. To clarify the roles of the parental genomes in placentation, we previously established TS cells from androgenetic embryos (AGTS cells). AGTS cells are in the undifferentiated state when cultured with Fgf4 and express undifferentiated marker genes. After removing Fgf4, AGTS cells differentiate into trophoblast giant cells (TGCs), but not into spongiotrophoblast cells, and some of the AGTS cells continue to proliferate. In this study, we investigated the differentiation potency of AGTS cells by analyzing the expression of undifferentiated marker genes and all trophoblast cell subtype-specific genes. After removing Fgf4, some undifferentiated marker genes (Cdx2, Eomes and Elf5) continued to be expressed. Interestingly, TGCs differentiated from AGTS cells also expressed Cdx2, but not Prl3d1. Moreover, the expression of Gcm1 and Synb was induced after the differentiation, indicating that AGTS cells preferentially differentiated into labyrinth progenitor cells. Cdx2 knockdown resulted in increased Prl3d1 expression, suggesting that Fgf4-independent Cdx2 expression inhibited the functional TGCs. Moreover, Fgf4-independent Cdx2 expression was activated by Gab1, one of the paternally expressed imprinted genes via the mitogen-activated protein kinase kinase (MEK)-extracellular signal regulated protein kinase (ERK) pathway. These results suggested that the paternal genome activates the MEK-ERK pathway without the Fgf4 signal, accelerates the differentiation into labyrinth progenitor cells and controls the function of TGCs.
cAMP/PKA/EGR1 signaling mediates the molecular mechanism of ethanol-induced inhibition of placental 11β-HSD2 expression.
Yu Luting,Zhou Jin,Zhang Guohui,Huang Wen,Pei Linguo,Lv Feng,Zhang Yuanzhen,Zhang Wei,Wang Hui
Toxicology and applied pharmacology
It is known that inhibiting 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) expression in the placenta can cause fetal over-exposure to maternal glucocorticoids and induce intrauterine growth restriction (IUGR); these effects ultimately increase the risk of adult chronic diseases. This study aimed to investigate the molecular mechanism of the prenatal ethanol exposure (PEE)-induced inhibition of placental 11β-HSD2 expression. Pregnant Wistar rats were intragastrically administered ethanol (4 g/kg/d) from gestational days 9 to 20. The levels of maternal and fetal serum corticosterone and placental 11β-HSD2-related gene expression were analyzed. Furthermore, we investigated the mechanism of reduced placental 11β-HSD2 expression induced by ethanol treatment (15-60 mM) in HTR-8/SVneo cells. In vivo, PEE decreased fetal body weights and increased maternal and fetal serum corticosterone and early growth response factor 1 (EGR1) expression levels. Moreover, histone modification changes (decreased acetylation and increased di-methylation of H3K9) to the HSD11B2 promoter and lower 11β-HSD2 expression levels were observed. In vitro, ethanol decreased cAMP/PKA signaling and 11β-HSD2 expression and increased EGR1 expression in a concentration-dependent manner. A cAMP agonist and EGR1 siRNA reversed the ethanol-induced inhibition of 11β-HSD2 expression. Together, PEE reduced placental 11β-HSD2 expression, and the underlying mechanism is associated with ethanol-induced histone modification changes to the HSD11B2 promoter through the cAMP/PKA/EGR1 pathway.
Diabetes mellitus activates signal transduction pathways resulting in vascular endothelial growth factor resistance of human monocytes.
Tchaikovski Vadim,Olieslagers Servé,Böhmer Frank-D,Waltenberger Johannes
BACKGROUND:Monocytes are cellular components of wound repair, arteriogenesis, and atherogenesis. Vascular endothelial growth factor (VEGF)-A and placental growth factor recruit monocytes to sites of arteriogenesis via stimulation of VEGF receptor-1 (VEGFR-1). The chemotactic response of monocytes to VEGF-A is attenuated in individuals with diabetes mellitus (DM). This VEGF resistance correlates with impaired collateral growth. The aim of this study is to elucidate the molecular basis of VEGF resistance and impaired monocyte response in DM. METHODS AND RESULTS:Phosphorylation of Akt, p38, and extracellular signal-regulated kinase 1/2 (ERK1/2) could be stimulated with either placental growth factor-1 or VEGF-A in monocytes from non-DM but not DM individuals. In contrast, formyl-methionyl-leucyl-phenylalanine caused a comparable activation of these molecules in both DM and non-DM monocytes. Baseline phosphorylation of Akt, p38, and ERK1/2 was significantly elevated in monocytes from DM compared with non-DM subjects. Of note, H(2)O(2) activated Akt, p38, and ERK1/2 in non-DM monocytes ex vivo. Protein tyrosine phosphatases had stronger oxidative modifications in monocytes from DM than from non-DM individuals, which reflects functional protein tyrosine phosphatase inhibition, similar to that seen after H(2)O(2) challenge. Overall, protein tyrosine phosphatase and protein tyrosine phosphatase-1B activity were reduced in DM monocytes. DM monocytes revealed higher expression of the receptor for advanced glycation end products. Stimulation with advanced glycation end products ligands resulted in activation of non-DM monocytes and inhibition of VEGFR-1-mediated chemotaxis. The elevated baseline phosphorylation/activation of Akt, p38, and ERK1/2 in DM monocytes likely causes the resistance to further stimulation with specific stimuli such as VEGF-A, revealing a molecular explanation of the DM-related signal transduction defect. CONCLUSIONS:We propose that elevated advanced glycation end products expression and increased oxidative stress in diabetic monocytes lead to activation of VEGFR-1-related signaling pathways and to desensitization of VEGFR-1 responses. These data establish VEGF resistance as a novel molecular concept for DM-related cellular dysfunction.
The SK3 channel promotes placental vascularization by enhancing secretion of angiogenic factors.
Rada Cara C,Murray Grace,England Sarah K
American journal of physiology. Endocrinology and metabolism
Proper placental perfusion is essential for fetal exchange of oxygen, nutrients, and waste with the maternal circulation. Impairment of uteroplacental vascular function can lead to pregnancy complications, including preeclampsia and intrauterine growth restriction (IUGR). Potassium channels have been recognized as regulators of vascular proliferation, angiogenesis, and secretion of vasoactive factors, and their dysfunction may underlie pregnancy-related vascular diseases. Overexpression of one channel in particular, the small-conductance calcium-activated potassium channel 3 (SK3), is known to increase vascularization in mice, and mice overexpressing the SK3 channel (SK3(T/T) mice) have a high rate of fetal demise and IUGR. Here, we show that overexpression of SK3 causes fetal loss through abnormal placental vascularization. We previously reported that, at pregnancy day 14, placentas isolated from SK3(T/T) mice are smaller than those obtained from wild-type mice. In this study, histological analysis reveals that SK3(T/-) placentas at this stage have abnormal placental morphology, and microcomputed tomography shows that these placentas have significantly larger and more blood vessels than those from wild-type mice. To identify the mechanism by which these vascularization defects occur, we measured levels of vascular endothelial growth factor (VEGF), placental growth factor, and the soluble form of VEGF receptor 1 (sFlt-1), which must be tightly regulated to ensure proper placental development. Our data reveal that overexpression of SK3 alters systemic and placental ratios of the angiogenic factor VEGF to antiangiogenic factor sFlt-1 throughout pregnancy. Additionally, we observe increased expression of hypoxia-inducing factor 2α in SK3(T/-) placentas. We conclude that the SK3 channel modulates placental vascular development and fetal health by altering VEGF signaling.
Diversity in human placental microvascular endothelial cells and macrovascular endothelial cells.
Huang Xiaojie,Jia Linyan,Qian Zhen,Jia Yuanhui,Chen Xiao,Xu Xianghong,Chang Xinwen,Liu Ming,Wang Kai
Angiogenesis is fundamental to normal placental development, and aberrant angiogenesis contributes substantially to placental pathologies. Placental angiogenesis is a pivotal process that plays a key mechanistic role in the elaboration of the placental villous tree, which is mainly taken by human placental microvascular endothelial cells (HPMECs), present in the fetal capillaries of chorionic villi, and macrovascular human umbilical vein endothelial cells (HUVECs) also play a role in this process. These are the two types of endothelial cells that form the placenta and differ in morphology and function. The placental vasculature represents a distinct territory that is highly specialized in structure and function. To distinguish the differences between HPMECs and HUVECs, we isolated HPMECs by paramagnetic particle separation and HUVECs through trypsinization and validated their characteristics. Then, we examined their response to fibroblast growth factor 2 (FGF2), vascular endothelial growth factor (VEGF) and endocrine-gland-derived vascular endothelial growth factor (EG-VEGF), as well as the underlying signaling mechanisms and their transcriptomes. We found that cultured HPMECs and HUVECs took up DiI-Ac-LDL and formed capillary-like tube structures on Matrigel. HPMECs and HUVECs had different expressions of eNOS, PROKR1 and PROKR2, and these characteristics substantiate the endothelial nature of cultured cells. FGF2 and VEGF stimulated the proliferation and migration of HPMECs and HUVECs via activation of PI3K/AKT1 and MEK1/MEK2/ERK1/ERK2. Interestingly, EG-VEGF increased the proliferation and migration of HPMECs via only MEK1/MEK2/ERK1/ERK2 and not PI3K/AKT1. Microarray analysis showed that there were some differentially expressed genes between HPMECs and HUVECs. Gene ontology analysis indicated that the differentially expressed genes were highly related to G-protein coupled receptor signaling pathway, angiogenesis, L-lysine transmembrane transport and blood vessel remodeling. These data provided evidence of heterogeneity between microvascular HPMECs and macrovascular HUVECs that most likely reflected significant differences in endothelial cell function in the two different cellular environments.
Coordinated expression of TNFα- and VEGF-mediated signaling components by placental macrophages in early and late pregnancy.
Pavlov O V,Niauri D A,Selutin A V,Selkov S A
INTRODUCTION:Mononuclear phagocytes are thought to significantly contribute to cytokine regulation at the maternal-foetal interface, but the role of placental macrophages has been poorly investigated. TNFα and VEGF were demonstrated to have regulatory effects on basic structures of the placenta, particularly the trophoblast and blood vessels. The aims of this study were to determine the expression of TNFα, VEGF and related receptors in placental macrophages, and how does the participation of placental macrophages alter with gestational age in TNFα- and VEGF-mediated signaling. METHODS:Macrophages were isolated from placental villous tissue from normal pregnancies at either 9-12 or 38-40 weeks gestation. Cell surface receptors (TNFR1, TNFR2, VEGFR1, and VEGFR2) and intracellular TNFα and VEGF were quantified by flow cytometry after antibody staining. Basal and stimulated secretion of both cytokines and soluble TNF receptors was quantified by cytometric bead arrays. Secreted VEGFR1 was measured by ELISA. RESULTS:The expression of TNFR1 and VEGFR1 was remarkably variable and did not change from first to third trimester. There was minimal basal TNFα production in the placental macrophages, but nearly all cells in the population produced VEGF. TNFα and VEGF secretion increased with gestational age accompanied by decreased secretion of the antagonists sTNFR1 and sVEGFR. Macrophages isolated from early term placentas were less effective in responding to bacterial endotoxin. Lipopolysaccharide induced increases in the secretion of TNFα, TNFR1, TNFR2, and VEGFR1 but did not affect the production of VEGF. In late pregnancy, a significant correlation was observed between TNFR1 and VEGFR1. DISCUSSION:The progression of pregnancy is accompanied by the concerted increase in TNFα and VEGF secretion and decrease in the production of their soluble receptors, but the expression of cell surface receptors does not depend on gestational age. The observed patterns of basal and stimulated expression of TNFα and VEGF may reflect the dual immune and morphogenetic roles of placental macrophages in gestation. Compatible patterns of TNFR1 and VEGFR1 expression suggest common regulatory pathways for these receptors.
Cadmium disrupts signaling of the hypoxia-inducible (HIF) and transforming growth factor (TGF-β) pathways in placental JEG-3 trophoblast cells via reactive oxygen species.
Adebambo Oluwadamilare A,Shea Damian,Fry Rebecca C
Toxicology and applied pharmacology
Epidemiologic studies indicate an association between exposure to cadmium (Cd) and placental-related pregnancy disorders. While a precise mechanism is unknown, oxidative imbalance and dysregulation of the hypoxia inducible factor (HIF) and transforming growth factor beta (TGF-β) pathways have been implicated in placental disease pathogenesis. Here we investigated key oxidative and placentation pathways in JEG-3 placental trophoblast cells treated with Cd alone, environmental water samples predominated by Cd with low concentrations of other metals (e.g. inorganic arsenic (iAs)) collected from a waste-site, and a matched mixture of Cd and iAs prepared in the laboratory. The induction of cytosolic reactive oxygen species (ROS), expression of metallothionein (MT) isoforms, HIF1α and downstream targets, and expression of TGFβ pathway-associated genes and proteins were assessed. Additionally, the effect of pre-treatment with the antioxidant N-acetyl cysteine (NAC) on ROS generation and effects on HIF, MT and TGF-β signaling pathways was examined. Cd and Cd-mixture treated cells displayed higher levels of ROSs with accompanying disruption of HIF and TGFβ pathway signaling versus controls, with the Cd-mixture eliciting a greater effect. Conversely, pretreatment with NAC reduced Cd-induced ROS production and disruption of HIF, MT and TGFβ pathway signaling. The results indicate that treatment of placental trophoblast cells with Cd results in increased production of ROSs that disrupt placentation pathways involved in disease pathogenesis. Also, co-occurrence of Cd with other toxic metals, particularly arsenic, may induce detrimental health effects that are currently underestimated when analyzed as single metals.
Defining contributions of paternally methylated imprinted genes at the Igf2-H19 and Dlk1-Gtl2 domains to mouse placentation by transcriptomic analysis.
Kawahara Manabu,Morita Shinnosuke,Takahashi Nozomi,Kono Tomohiro
The Journal of biological chemistry
Parental genome functions in ontogeny are determined by interactions among transcripts from the maternal and paternal genomes, which contain many genes whose expression is strictly dependent on their parental origin as a result of genomic imprinting. Comprehensive recognition of the interactions between parental genomes is important for understanding genomic imprinting in mammalian development. The placenta is a key organ for exploring the biological significance of genomic imprinting. To decipher the unknown roles of paternally methylated imprinted genes on chromosomes 7 and 12 in mouse placentation, we performed a transcriptomic analysis on placentae in three types of bimaternal conceptuses that contained genomes derived from both non-growing and fully grown oocytes. Furthermore, we used the Ingenuity pathway analysis software to predict key networks and identify functions specific to paternally methylated imprinted genes regulated by the Igf2-H19 imprinting control region and Dlk1-Dio3 imprinting control region. The data suggested that dynamic conversion of the gene expression profile by restoring the expression of paternally methylated imprinted genes resulted in phenotypic improvements in bimaternal placentae. These results provide a framework to further explore the role of epigenetic modifications in paternal genome during mouse placentation.
DNA methylation-independent growth restriction and altered developmental programming in a mouse model of preconception male alcohol exposure.
Chang Richard C,Skiles William M,Chronister Sarah S,Wang Haiqing,Sutton Gabrielle I,Bedi Yudhishtar S,Snyder Matthew,Long Charles R,Golding Michael C
The preconception environment is a significant modifier of dysgenesis and the development of environmentally-induced disease. To date, fetal alcohol spectrum disorders (FASDs) have been exclusively associated with maternal exposures, yet emerging evidence suggests male-inherited alterations in the developmental program of sperm may be relevant to the growth-restriction phenotypes of this condition. Using a mouse model of voluntary consumption, we find chronic preconception male ethanol exposure associates with fetal growth restriction, decreased placental efficiency, abnormalities in cholesterol trafficking, sex-specific alterations in the genetic pathways regulating hepatic fibrosis, and disruptions in the regulation of imprinted genes. Alterations in the DNA methylation profiles of imprinted loci have been identified in clinical studies of alcoholic sperm, suggesting the legacy of paternal drinking may transmit via heritable disruptions in the regulation of imprinted genes. However, the capacity of sperm-inherited changes in DNA methylation to broadly transmit environmentally-induced phenotypes remains unconfirmed. Using bisulphite mutagenesis and second-generation deep sequencing, we find no evidence to suggest that these phenotypes or any of the associated transcriptional changes are linked to alterations in the sperm-inherited DNA methylation profile. These observations are consistent with recent studies examining the male transmission of diet-induced phenotypes and emphasize the importance of epigenetic mechanisms of paternal inheritance beyond DNA methylation. This study challenges the singular importance of maternal alcohol exposures and suggests paternal alcohol abuse is a significant, yet overlooked epidemiological factor complicit in the genesis of alcohol-induced growth defects, and may provide mechanistic insight into the failure of FASD children to thrive postnatally.
Preconception paternal alcohol exposure exerts sex-specific effects on offspring growth and long-term metabolic programming.
Chang Richard C,Wang Haiqing,Bedi Yudhishtar,Golding Michael C
Epigenetics & chromatin
BACKGROUND:Although clinical data support an association between paternal alcohol use and deficits in child neurocognitive development, the relationship between paternal drinking and alcohol-induced growth phenotypes remains challenging to define. Using an established mouse model of chronic exposure, previous work by our group has linked preconception paternal alcohol use to sex-specific patterns of fetal growth restriction and placental dysfunction. The aim of the present study was to investigate the long-term impact of chronic preconception paternal alcohol use on offspring growth and metabolic programming. RESULTS:Preconception paternal alcohol exposure induced a prolonged period of fetal gestation and an increased incidence of intrauterine growth restriction, which affected the male offspring to a greater extent than the females. While the female offspring of ethanol-exposed males were able to match the body weights of the controls within the first 2 weeks of postnatal life, male offspring continued to display an 11% reduction in weight at 5 weeks of age and a 6% reduction at 8 weeks of age. The observed growth deficits associated with insulin hypersensitivity in the male offspring, while in contrast, females displayed a modest lag in their glucose tolerance test. These metabolic defects were associated with an up-regulation of genes within the pro-fibrotic TGF-β signaling pathway and increased levels of cellular hydroxyproline within the livers of the male offspring. We observed suppressed cytokine profiles within the liver and pancreas of both the male and female offspring, which correlated with the up-regulation of genes in the LiverX/RetinoidX/FarnesoidX receptor pathways. However, patterns of gene expression were highly variable between the offspring of alcohol-exposed sires. In the adult offspring of alcohol-exposed males, we did not observe any differences in the allelic expression of Igf2 or any other imprinted genes. CONCLUSIONS:The impact of paternal alcohol use on child development is poorly explored and represents a significant gap in our understanding of the teratogenic effects of ethanol. Our studies implicate paternal exposure history as an additional and important modifier of alcohol-induced growth phenotypes and challenge the current maternal-centric exposure paradigm.
In vitro fertilization placenta overgrowth in mice is associated with downregulation of the paternal imprinting gene H19.
Xiang Meng,Ma Yuan,Lei Hui,Wen Liang,Chen Shuqiang,Wang Xiaohong
Molecular reproduction and development
In vitro fertilization (IVF) is a widely used assisted reproductive technology for individuals with infertility that may cause placental maldevelopment, which is harmful to the future health of the offspring. In this study, using a mouse model, we not only revealed changes in the placenta caused by IVF at embryonic day 18.5 (E18.5), but also attempted to identify factors that correlate with IVF-induced abnormal placental development. Our results demonstrate that IVF-induced placental maldevelopment is associated with hypermethylation of the imprinting control region of the H19 imprinted maternally expressed transcript (H19). IVF, by inducing overexpression of DNA methyltransferase 3β, downregulated H19 and the derived miR675, resulting in the activation of insulin-like growth factor signaling and its downstream phosphoinositide 3-kinase/AKT/mammalian target of rapamycin pathway. Therefore, we provided the first evidence of the molecular signaling pathways that link imprint genes, protein encoding genes, long noncoding RNAs, and microRNAs. This may provide new insights to inform the development of improved operational techniques for IVF and life-long health of the offspring.
Imprinted genes influencing the quality of maternal care.
Creeth H D J,McNamara G I,Isles A R,John R M
Frontiers in neuroendocrinology
In mammals successful rearing imposes a cost on later reproductive fitness specifically on the mother creating the potential for parental conflict. Loss of function of three imprinted genes in the dam results in deficits in maternal care suggesting that, like maternal nutrients, maternal care is a resource over which the parental genomes are in conflict. The induction of maternal care is a complex, highly regulated process and it is unsurprising that many gene disruptions and environmental adversities result in maternal care deficits. However, recent compelling evidence for a more purposeful imprinting phenomenon comes from observing alterations in the mother's behaviour when expression of the imprinted genes Phlda2 and Peg3 has been manipulated solely in the offspring. This explicit demonstration that imprinted genes expressed in the offspring influence maternal behaviour lends significant weight to the hypothesis that maternal care is a resource that has been manipulated by the paternal genome.
Igf2 deletion alters mouse placenta endocrine capacity in a sexually dimorphic manner.
Aykroyd Bethany R L,Tunster Simon J,Sferruzzi-Perri Amanda N
The Journal of endocrinology
The placenta regulates materno-fetal nutrient transfer and secretes hormones that enable maternal physiological support of the pregnancy. In mice, these functions are performed by the labyrinth (Lz) and junctional (Jz) zones, respectively. Insulin-like growth factor 2 (Igf2) is an imprinted gene expressed by the conceptus that is important for promoting fetal growth and placenta formation. However, the specific role of Igf2 in the Jz in regulating placental endocrine function and fetal development is unknown. This study used a novel model to investigate the effect of conditional loss of Igf2 in the Jz (Jz-Igf2UE) on placental endocrine cell formation and the expression of hormones and IGF signaling components in placentas from female and male fetuses. Jz-Igf2UE altered gross placental structure and expression of key endocrine and signaling genes in a sexually dimorphic manner. The volumes of spongiotrophoblast and glycogen trophoblast in the Jz were decreased in placentas from female but not male fetuses. Expression of insulin receptor was increased and expression the MAPK pathway genes (Mek1, P38α) decreased in the placental Jz of female but not male fetuses. In contrast, expression of the type-1 and -2 IGF receptors and the MAPK pathway genes (H-ras, N-ras, K-ras) was decreased in the placental Jz from male but not female fetuses. Expression of the steroidogenic gene, Cyp17a1, was increased and placental lactogen-2 was decreased in the placenta of both sexes. In summary, we report that Jz-Igf2UE alters the cellular composition, IGF signaling components and hormone expression of the placental Jz in a manner largely dependent on fetal sex.
The imprinted polycomb group gene Sfmbt2 is required for trophoblast maintenance and placenta development.
Miri Kamelia,Latham Keith,Panning Barbara,Zhong Zhisheng,Andersen Angela,Varmuza Susannah
Development (Cambridge, England)
Imprinted genes play important roles in placenta development and function. Parthenogenetic embryos, deficient in paternally expressed imprinted genes, lack extra-embryonic tissues of the trophoblast lineage. Parthenogenetic trophoblast stem cells (TSCs) are extremely difficult to derive, suggesting that an imprinted gene(s) is necessary for TSC establishment or maintenance. In a candidate study, we were able to narrow the list to one known paternally expressed gene, Sfmbt2. We show that mouse embryos inheriting a paternal Sfmbt2 gene trap null allele have severely reduced placentae and die before E12.5 due to reduction of all trophoblast cell types. We infected early embryos with lentivirus vectors expressing anti-Sfmbt2 shRNAs and found that TSC derivation was significantly reduced. Together, these observations support the hypothesis that loss of SFMBT2 results in defects in maintenance of trophoblast cell types necessary for development of the extra-embryonic tissues, the placenta in particular.
Aquaporin-1, a New Maternally Expressed Gene, Regulates Placental Development in the Mouse.
Guo Jing,He Hongjuan,Liu Hui,Liu Qi,Zhang Lili,Liu Boqi,Sugimoto Kenkichi,Wu Qiong
Biology of reproduction
Imprinted genes play an important role in placental and embryonic development. Abnormalities in their regulation can result in placental and embryonic dysplasia, leading to congenital diseases. The imprinting state, expression, and function of aquaporin-1 (Aqp1) were explored in knockout mice by imprinting analysis, real-time PCR, and immunohistochemistry. In the present study, Aqp1 was identified as a new, imprinted, and placenta-specific maternally expressed gene in the mouse. Compared with wild-type Aqp1(+/+) mice, there was significant placental and embryonic overgrowth in Aqp1(-/+) (loss of maternal allele) and Aqp1(-/-) mice, but not in Aqp1(+/-) (loss of paternal allele) mice at Embryonic Day (E) 12.5-E18.5. In addition, the masses of Postnatal Day 0 (P0) embryos (Aqp1(-/-) and Aqp1(-/+)) were highest among the four types. In Aqp1(-/+) and Aqp1(-/-) mice, phenotypic analysis indicated that the number and branching of blood vessels, as well as the labyrinth area, increased significantly in placentae of E12.5-E18.5 mice. Moreover, there were abnormalities in the placental junctional zone and the labyrinthine zone at E15.5. Quantitative analysis showed that Aqp1 expression decreased significantly in the placentae of Aqp1(-/+) and Aqp1(-/-) mice at E15.5, and that the AQP1 protein expression signals were detected weakly in the decidual and spongioblast layers. Our results demonstrate that Aqp1 is maternally expressed in the placenta, and that its deficiency resulted in placental abnormalities in the mouse. Aqp1 may have a specific inhibitory role in mouse placental development. These results provide new insights for the treatment of diseases relating to placental and embryonic development.
Placenta-specific epimutation at H19-DMR among common pregnancy complications: its frequency and effect on the expression patterns of H19 and IGF2.
Yamaguchi Yuko,Tayama Chiharu,Tomikawa Junko,Akaishi Rina,Kamura Hiromi,Matsuoka Kentaro,Wake Norio,Minakami Hisanori,Kato Kiyoko,Yamada Takahiro,Nakabayashi Kazuhiko,Hata Kenichiro
BACKGROUND:H19 and IGF2 genes are imprinted and involved in regulating fetal and placental growth. The H19 differentially methylated region (DMR) is paternally methylated and maternally unmethylated and regulates the imprinted expression of H19 and IGF2. Epimutation at the H19-DMR in humans results in congenital growth disorders, Beckwith-Wiedemann and Silver-Russell syndromes, when erroneously its maternal allele becomes methylated and its paternal allele becomes unmethylated, respectively. Although H19 and IGF2 have been assessed for their involvement in pregnancy complications including fetal growth restriction (FGR) and pregnancy-induced hypertension (PIH)/hypertensive disorder of pregnancy (HDP) intensively in the last decade, it is still not established whether epimutation at the H19-DMR in the placenta results in pathogenic conditions in pregnancy. We aimed to assess the frequency of H19-DMR epimutation and its effects on the allelic expression patterns of H19 and IGF2 genes among normal and abnormal pregnancy cases. RESULTS:We enrolled two independently collected sets of placenta samples from normal pregnancies as controls and common pregnancy complications, FGR and PIH (HDP). The first set consisted of 39 controls and 140 FGR and/or PIH cases, and the second set consisted of 29 controls and 62 cases. For these samples, we initially screened for DNA methylation changes at H19-DMR and IGF2-DMRs by combined bisulfite restriction analysis, and further analyzed cases with methylation changes for their allelic methylation and expression patterns. We identified one case each of FGR and PIH showing hypomethylation of H19-DMR and IGF2-DMRs only in the placenta, but not in cord blood, from the first case/control set. For the PIH case, we were able to determine the allelic expression pattern of H19 to be biallelically expressed and the H19/IGF2 expression ratio to be highly elevated compared to controls. We also identified a PIH case with hypomethylation at H19-DMR and IGF2-DMRs in the placenta from the second case/control set. CONCLUSIONS:Placental epimutation at H19-DMR was observed among common pregnancy complication cases at the frequency of 1.5% (3 out of 202 cases examined), but not in 68 normal pregnancy cases examined. Alteration of H19/IGF2 expression patterns due to hypomethylation of H19-DMR may have been involved in the pathogenesis of pregnancy complications in these cases.
Paternal uniparental disomy 14 and related disorders: placental gene expression analyses and histological examinations.
Kagami Masayo,Matsuoka Kentaro,Nagai Toshiro,Yamanaka Michiko,Kurosawa Kenji,Suzumori Nobuhiro,Sekita Yoichi,Miyado Mami,Matsubara Keiko,Fuke Tomoko,Kato Fumiko,Fukami Maki,Ogata Tsutomu
Although recent studies in patients with paternal uniparental disomy 14 [upd(14)pat] and other conditions affecting the chromosome 14q32.2 imprinted region have successfully identified underlying epigenetic factors involved in the development of upd(14)pat phenotype, several matters, including regulatory mechanism(s) for RTL1 expression, imprinting status of DIO3 and placental histological characteristics, remain to be elucidated. We therefore performed molecular studies using fresh placental samples from two patients with upd(14)pat. We observed that RTL1 expression level was about five times higher in the placental samples of the two patients than in control placental samples, whereas DIO3 expression level was similar between the placental samples of the two patients and the control placental samples. We next performed histological studies using the above fresh placental samples and formalin-fixed and paraffin-embedded placental samples obtained from a patient with a maternally derived microdeletion involving DLK1, the-IG-DMR, the MEG3-DMR and MEG3. Terminal villi were associated with swollen vascular endothelial cells and hypertrophic pericytes, together with narrowed capillary lumens. DLK1, RTL1 and DIO3 proteins were specifically identified in vascular endothelial cells and pericytes, and the degree of protein staining was well correlated with the expression dosage of corresponding genes. These results suggest that RTL1as-encoded microRNA functions as a repressor of RTL1 expression, and argue against DIO3 being a paternally expressed gene. Furthermore, it is inferred that DLK1, DIO3 and, specially, RTL1 proteins, play a pivotal role in the development of vascular endothelial cells and pericytes.
Unearthing the roles of imprinted genes in the placenta.
Bressan F F,De Bem T H C,Perecin F,Lopes F L,Ambrosio C E,Meirelles F V,Miglino M A
Mammalian fetal survival and growth are dependent on a well-established and functional placenta. Although transient, the placenta is the first organ to be formed during pregnancy and is responsible for important functions during development, such as the control of metabolism and fetal nutrition, gas and metabolite exchange, and endocrine control. Epigenetic marks and gene expression patterns in early development play an essential role in embryo and fetal development. Specifically, the epigenetic phenomenon known as genomic imprinting, represented by the non-equivalence of the paternal and maternal genome, may be one of the most important regulatory pathways involved in the development and function of the placenta in eutherian mammals. A lack of pattern or an imprecise pattern of genomic imprinting can lead to either embryonic losses or a disruption in fetal and placental development. Genetically modified animals present a powerful approach for revealing the interplay between gene expression and placental function in vivo and allow a single gene disruption to be analyzed, particularly focusing on its role in placenta function. In this paper, we review the recent transgenic strategies that have been successfully created in order to provide a better understanding of the epigenetic patterns of the placenta, with a special focus on imprinted genes. We summarize a number of phenotypes derived from the genetic manipulation of imprinted genes and other epigenetic modulators in an attempt to demonstrate that gene-targeting studies have contributed considerably to the knowledge of placentation and conceptus development.
Imprinted genes and the epigenetic regulation of placental phenotype.
Fowden A L,Coan P M,Angiolini E,Burton G J,Constancia M
Progress in biophysics and molecular biology
Imprinted genes are expressed in a parent-of-origin manner by epigenetic modifications that silence either the paternal or maternal allele. They are widely expressed in fetal and placental tissues and are essential for normal placental development. In general, paternally expressed genes enhance feto-placental growth while maternally expressed genes limit conceptus growth, consistent with the hypothesis that imprinting evolved in response to the conflict between parental genomes in the allocation of maternal resources to fetal growth. Using targeted deletion, uniparental duplication, loss of imprinting and transgenic approaches, imprinted genes have been shown to determine the transport capacity of the definitive mouse placenta by regulating its growth, morphology and transporter abundance. Imprinted genes in the placenta are also responsive to environmental challenges and adapt placental phenotype to the prevailing nutritional conditions, in part, by varying their epigenetic status. In addition, interplay between placental and fetal imprinted genes is important in regulating resource partitioning via the placenta both developmentally and in response to environmental factors. By balancing the opposing parental drives on resource allocation with the environmental signals of nutrient availability, imprinted genes, like the Igf2-H19 locus, may act as nutrient sensors and optimise the fetal acquisition of nutrients for growth. These genes, therefore, have a major role in the epigenetic regulation of placental phenotype with long term consequences for the developmental programming of adult health and disease.
Temporal regulation of prenatal embryonic development by paternal imprinted loci.
Li Qing,Li Yuanyuan,Yin Qi,Huang Shuo,Wang Kai,Zhuo Liangchai,Li Wei,Chang Boran,Li Jinsong
Science China. Life sciences
Paternal imprinted genes (H19 and Gtl2) are pivotal for prenatal embryonic development in mice. Nongrowing oocytes and sperm- or oocyte-originated haploid embryonic stem cells (haESCs) carrying both H19-DMR (differentially DNA-methylated region) and IG (intergenic)-DMR deletions that partially mimic paternal imprinting of H19-Igf2 and Dlk1-Dio3 can be employed as sperm replacement to efficiently support full-term embryonic development. However, how H19-DMR and IG-DMR act together to regulate embryonic development is still largely unknown. Here, using androgenetic haESC (AG-haESC)-mediated semi-cloned (SC) technology, we showed that paternal H19-DMR and IG-DMR are not essential for pre-implantation development of SC embryos generated through injection of AG-haESCs into oocytes. H19-DMR plays critical roles before 12.5 days of gestation while IG-DMR is essential for late-gestation of SC embryos. Interestingly, we found that combined deletions of H19 and H19-DMR can further improve the efficiency of normal development of SC embryos at mid-gestation compared to DKO SC embryos. Transcriptome and histology analyses revealed that H19 and H19-DMR combined deletions rescue the placental defects. Furthermore, we showed that H19, H19-DMR and IG-DMR deletions (TKO) give rise to better prenatal and postnatal embryonic development of SC embryos compared to DKO. Together, our results indicate the temporal regulation of paternal imprinted loci during embryonic development.
Paternally expressed genes predominate in the placenta.
Wang Xu,Miller Donald C,Harman Rebecca,Antczak Douglas F,Clark Andrew G
Proceedings of the National Academy of Sciences of the United States of America
The discovery of genomic imprinting through studies of manipulated mouse embryos indicated that the paternal genome has a major influence on placental development. However, previous research has not demonstrated paternal bias in imprinted genes. We applied RNA sequencing to trophoblast tissue from reciprocal hybrids of horse and donkey, where genotypic differences allowed parent-of-origin identification of most expressed genes. Using this approach, we identified a core group of 15 ancient imprinted genes, of which 10 were paternally expressed. An additional 78 candidate imprinted genes identified by RNA sequencing also showed paternal bias. Pyrosequencing was used to confirm the imprinting status of six of the genes, including the insulin receptor (INSR), which may play a role in growth regulation with its reciprocally imprinted ligand, histone acetyltransferase-1 (HAT1), a gene involved in chromatin modification, and lymphocyte antigen 6 complex, locus G6C, a newly identified imprinted gene in the major histocompatibility complex. The 78 candidate imprinted genes displayed parent-of-origin expression bias in placenta but not fetus, and most showed less than 100% silencing of the imprinted allele. Some displayed variability in imprinting status among individuals. This variability results in a unique epigenetic signature for each placenta that contributes to variation in the intrauterine environment and thus presents the opportunity for natural selection to operate on parent-of-origin differential regulation. Taken together, these features highlight the plasticity of imprinting in mammals and the central importance of the placenta as a target tissue for genomic imprinting.
The Rodent-Specific MicroRNA Cluster within the Sfmbt2 Gene Is Imprinted and Essential for Placental Development.
Inoue Kimiko,Hirose Michiko,Inoue Hiroki,Hatanaka Yuki,Honda Arata,Hasegawa Ayumi,Mochida Keiji,Ogura Atsuo
MicroRNAs (miRNAs) represent small noncoding RNAs that are involved in physiological and developmental processes by posttranscriptionally inhibiting gene expression. One of the largest miRNA clusters in mice is located in intron 10 of the Sfmbt2 gene, containing 72 miRNA precursor sequences. In this study, we generated mice lacking the entire Sfmbt2 miRNA cluster to elucidate its functions during development. The Sfmbt2 miRNAs were expressed predominantly from the paternal allele in the placenta, as is the host Sfmbt2 gene. Loss of the paternal allele resulted in severely impaired development of the placenta, especially the spongiotrophoblast layer, and frequent lethality or defects of fetuses. The predicted target sequences of the miRNAs and gene expression analysis defined at least nine putative target genes, which function as tumor suppressors or apoptosis inducers. Our study has provided experimental evidence for the indispensable roles of placental miRNAs in trophoblast proliferation and thus fetal development.
Epigenetics as a mechanism linking developmental exposures to long-term toxicity.
Barouki R,Melén E,Herceg Z,Beckers J,Chen J,Karagas M,Puga A,Xia Y,Chadwick L,Yan W,Audouze K,Slama R,Heindel J,Grandjean P,Kawamoto T,Nohara K
A variety of experimental and epidemiological studies lend support to the Developmental Origin of Health and Disease (DOHaD) concept. Yet, the actual mechanisms accounting for mid- and long-term effects of early-life exposures remain unclear. Epigenetic alterations such as changes in DNA methylation, histone modifications and the expression of certain RNAs have been suggested as possible mediators of long-term health effects of environmental stressors. This report captures discussions and conclusions debated during the last Prenatal Programming and Toxicity meeting held in Japan. Its first aim is to propose a number of criteria that are critical to support the primary contribution of epigenetics in DOHaD and intergenerational transmission of environmental stressors effects. The main criteria are the full characterization of the stressors, the actual window of exposure, the target tissue and function, the specificity of the epigenetic changes and the biological plausibility of the linkage between those changes and health outcomes. The second aim is to discuss long-term effects of a number of stressors such as smoking, air pollution and endocrine disruptors in order to identify the arguments supporting the involvement of an epigenetic mechanism. Based on the developed criteria, missing evidence and suggestions for future research will be identified. The third aim is to critically analyze the evidence supporting the involvement of epigenetic mechanisms in intergenerational and transgenerational effects of environmental exposure and to particularly discuss the role of placenta and sperm. While the article is not a systematic review and is not meant to be exhaustive, it critically assesses the contribution of epigenetics in the long-term effects of environmental exposures as well as provides insight for future research.
Early life lessons: The lasting effects of germline epigenetic information on organismal development.
Galan Carolina,Krykbaeva Marina,Rando Oliver J
BACKGROUND:An organism's metabolic phenotype is primarily affected by its genotype, its lifestyle, and the nutritional composition of its food supply. In addition, it is now clear from studies in many different species that ancestral environments can also modulate metabolism in at least one to two generations of offspring. SCOPE OF REVIEW:We limit ourselves here to paternal effects in mammals, primarily focusing on studies performed in inbred rodent models. Although hundreds of studies link paternal diets and offspring metabolism, the mechanistic basis by which epigenetic information in sperm programs nutrient handling in the next generation remains mysterious. Our goal in this review is to provide a brief overview of paternal effect paradigms and the germline epigenome. We then pivot to exploring one key mystery in this literature: how do epigenetic changes in sperm, most of which are likely to act transiently in the early embryo, ultimately direct a long-lasting physiological response in offspring? MAJOR CONCLUSIONS:Several potential mechanisms exist by which transient epigenetic modifications, such as small RNAs or methylation states erased shortly after fertilization, could be transferred to more durable heritable information. A detailed mechanistic understanding of this process will provide deep insights into early development, and could be of great relevance for human health and disease.
Paternal activation of CB cannabinoid receptor impairs placental and embryonic growth via an epigenetic mechanism.
Innocenzi Elisa,De Domenico Emanuela,Ciccarone Fabio,Zampieri Michele,Rossi Gabriele,Cicconi Rosella,Bernardini Roberta,Mattei Maurizio,Grimaldi Paola
The cannabinoid receptor type 2 (CB) is the peripheral receptor for cannabinoids, involved in the homeostatic control of several physiological functions. Male mitotic germ cells express a high level of CB, whose activation promotes their differentiation in both in vitro and in vivo experiments, controlling the correct progression of spermatogenesis. However, it remains elusive if CB activation in spermatogonia could affect reproductive success in terms of fertility and healthy pregnancy outcomes. In this study, we explored the effects of male CB activation on sperm number and quality and its influence on next generation health. We show that exposure of male mice to JWH-133, a selective CB agonist, decreased sperm count, impaired placental development and reduced offspring growth. These defects were associated with altered DNA methylation/hydroxymethylation levels at imprinted genes in sperm and conserved in placenta. Our findings reveal that paternal selective activation of CB alters the sperm epigenome and compromises offspring growth. This study demonstrates, for the first time, a new role of CB signaling in male gametes in causing epigenetic alterations that can be transmitted to the next generation by sperm, highlighting potential risks induced by recreational cannabinoid exposure.
DNA methylation profiles in preeclampsia and healthy control placentas.
Yeung Kristen R,Chiu Christine L,Pidsley Ruth,Makris Angela,Hennessy Annemarie,Lind Joanne M
American journal of physiology. Heart and circulatory physiology
Preeclampsia is a hypertensive disorder of pregnancy that affects 3-5% of all pregnancies. There is evidence to suggest that epigenetic mechanisms, such as DNA methylation, play a role in placental development and function. This study compared DNA methylation profiles of placentas from preeclampsia-affected pregnancies with placentas from healthy pregnancies to identify gene-specific changes in DNA methylation that may contribute to the development of preeclampsia. The methylation status of eight placental biopsies taken from preeclampsia-affected and 16 healthy pregnancies was analyzed using the Illumina Infinium Methylation 450 BeadChip array. Bisulfite pyrosequencing was used to confirm regions found to be differentially methylated between preeclampsia and healthy placentas. A total of 303 differentially methylated regions, 214 hypermethylated and 89 hypomethylated, between preeclampsia cases and controls were identified, after adjusting for gestational age (adjusted P < 0.05). Functional annotation found cell adhesion, wingless type MMTV Integration Site family member 2 (Wnt) signaling pathway, and regulation of transcription were significantly enriched in these gene regions. Hypermethylation of WNT2, sperm equatorial segment protein (SPESP1), NADPH oxidase 5 (NOX5), and activated leukocyte cell adhesion molecule (ALCAM) in preeclampsia placentas was confirmed with pyrosequencing. This study found differences in methylation in gene regions involved in cell signaling (WNT2), fertilization and implantation (SPESP1), reactive oxygen species signaling (NOX5), and cell adhesion (ALCAM). These results build on recently published studies that have reported significant differences in DNA methylation in preeclampsia placentas.
Human Oocyte-Derived Methylation Differences Persist in the Placenta Revealing Widespread Transient Imprinting.
Sanchez-Delgado Marta,Court Franck,Vidal Enrique,Medrano Jose,Monteagudo-Sánchez Ana,Martin-Trujillo Alex,Tayama Chiharu,Iglesias-Platas Isabel,Kondova Ivanela,Bontrop Ronald,Poo-Llanillo Maria Eugenia,Marques-Bonet Tomas,Nakabayashi Kazuhiko,Simón Carlos,Monk David
Thousands of regions in gametes have opposing methylation profiles that are largely resolved during the post-fertilization epigenetic reprogramming. However some specific sequences associated with imprinted loci survive this demethylation process. Here we present the data describing the fate of germline-derived methylation in humans. With the exception of a few known paternally methylated germline differentially methylated regions (DMRs) associated with known imprinted domains, we demonstrate that sperm-derived methylation is reprogrammed by the blastocyst stage of development. In contrast a large number of oocyte-derived methylation differences survive to the blastocyst stage and uniquely persist as transiently methylated DMRs only in the placenta. Furthermore, we demonstrate that this phenomenon is exclusive to primates, since no placenta-specific maternal methylation was observed in mouse. Utilizing single cell RNA-seq datasets from human preimplantation embryos we show that following embryonic genome activation the maternally methylated transient DMRs can orchestrate imprinted expression. However despite showing widespread imprinted expression of genes in placenta, allele-specific transcriptional profiling revealed that not all placenta-specific DMRs coordinate imprinted expression and that this maternal methylation may be absent in a minority of samples, suggestive of polymorphic imprinted methylation.
Intergenerational impact of paternal lifetime exposures to both folic acid deficiency and supplementation on reproductive outcomes and imprinted gene methylation.
Ly Lundi,Chan Donovan,Aarabi Mahmoud,Landry Mylène,Behan Nathalie A,MacFarlane Amanda J,Trasler Jacquetta
Molecular human reproduction
STUDY QUESTION:Do paternal exposures to folic acid deficient (FD), and/or folic acid supplemented (FS) diets, throughout germ cell development adversely affect male germ cells and consequently offspring health outcomes? SUMMARY ANSWER:Male mice exposed over their lifetimes to both FD and FS diets showed decreased sperm counts and altered imprinted gene methylation with evidence of transmission of adverse effects to the offspring, including increased postnatal-preweaning mortality and variability in imprinted gene methylation. WHAT IS KNOWN ALREADY:There is increasing evidence that disruptions in male germ cell epigenetic reprogramming are associated with offspring abnormalities and intergenerational disease. The fetal period is the critical time of DNA methylation pattern acquisition for developing male germ cells and an adequate supply of methyl donors is required. In addition, DNA methylation patterns continue to be remodeled during postnatal spermatogenesis. Previous studies have shown that lifetime (prenatal and postnatal) folic acid deficiency can alter the sperm epigenome and increase the incidence of fetal morphological abnormalities. STUDY DESIGN, SIZE, DURATION:Female BALB/c mice (F0) were placed on one of four amino-acid defined diets for 4 weeks before pregnancy and throughout pregnancy and lactation: folic acid control (Ctrl; 2 mg/kg), 7-fold folic acid deficient (7FD; 0.3 mg/kg), 10-fold high FS (10FS, 20 mg/kg) or 20-fold high FS (20FS, 40 mg/kg) diets. F1 males were weaned to their respective prenatal diets to allow for diet exposure during all windows of germline epigenetic reprogramming: the erasure, re-establishment and maintenance phases. PARTICIPANTS/MATERIALS, SETTINGS, METHODS:F0 females were mated with chow-fed males to produce F1 litters whose germ cells were exposed to the diets throughout embryonic development. F1 males were subsequently mated with chow-fed female mice. Two F2 litters, unexposed to the experimental diets, were generated from each F1 male; one litter was collected at embryonic day (E)18.5 and one delivered and followed postnatally. DNA methylation at a global level and at the differentially methylated regions of imprinted genes (H19, Imprinted Maternally Expressed Transcript (Non-Protein Coding)-H19, Small Nuclear Ribonucleoprotein Polypeptide N-Snrpn, KCNQ1 Opposite Strand/Antisense Transcript 1 (Non-Protein Coding)-Kcnq1ot1, Paternally Expressed Gene 1-Peg1 and Paternally Expressed Gene 3-Peg3) was assessed by luminometric methylation analysis and bisulfite pyrosequencing, respectively, in F1 sperm, F2 E18.5 placenta and F2 E18.5 brain cortex. MAIN RESULTS AND THE ROLE OF CHANCE:F1 males exhibited lower sperm counts following lifetime exposure to both folic acid deficiency and the highest dose of folic acid supplementation (20FS), (both P < 0.05). Post-implantation losses were increased amongst F2 E18.5 day litters from 20FS exposed F1 males (P < 0.05). F2 litters derived from both 7FD and 20FS exposed F1 males had significantly higher postnatal-preweaning pup death (both P < 0.05). Sperm from 10FS exposed males had increased variance in methylation across imprinted gene H19, P < 0.05; increased variance at a few sites within H19 was also found for the 7FD and 20FS groups (P < 0.05). While the 20FS diet resulted in inter-individual alterations in methylation across the imprinted genes Snrpn and Peg3 in F2 E18.5 placenta, ≥50% of individual sites tested in Peg1 and/or Peg3 were affected in the 7FD and 10FS groups. Inter-individual alterations in Peg1 methylation were found in F2 E18.5 day 10FS group brain cortex (P < 0.05). LARGE SCALE DATA:Not applicable. LIMITATIONS REASONS FOR CAUTION:The cause of the increase in postnatal-preweaning mortality was not investigated post-mortem. Further studies are required to understand the mechanisms underlying the adverse effects of folic acid deficiency and supplementation on developing male germ cells. Genome-wide DNA and histone methylome studies as well as gene expression studies are required to better understand the links between folic acid exposures, an altered germ cell epigenome and offspring outcomes. WIDER IMPLICATIONS OF THE FINDINGS:The findings of this study provide further support for paternally transmitted environmental effects. The results indicate that both folic acid deficiency and high dose supplementation can be detrimental to germ cell development and reproductive fitness, in part by altering DNA methylation in sperm. STUDY FUNDING AND COMPETING INTERESTS:This study was supported by a grant to J.M.T. from the Canadian Institutes of Health Research (CIHR #89944). The authors declare they have no conflicts of interest.
Paternal Folate Status and Sperm Quality, Pregnancy Outcomes, and Epigenetics: A Systematic Review and Meta-Analysis.
Hoek Jeffrey,Steegers-Theunissen Régine P M,Willemsen Sten P,Schoenmakers Sam
Molecular nutrition & food research
SCOPE:The effectiveness of maternal folate in reducing the risk of congenital malformations during pregnancy is well established. However, the role of the paternal folate status is scarcely investigated. The aim of this study is to investigate the evidence of associations between the paternal folate status and sperm quality, sperm epigenome, and pregnancy outcomes. METHODS AND RESULTS:Databases are searched up to December 2017 resulting in 3682 articles, of which 23 are retrieved for full-text assessment. Four out of thirteen human and two out of four animal studies show positive associations between folate concentrations and sperm parameters. An additional meta-analysis of four randomized controlled trials in subfertile men shows that the sperm concentration increases (3.54 95% confidence interval (CI) [-1.40 to 8.48]) after 3-6 months of 5 mg folic acid use per day compared to controls. Moreover, two out of two animal and one out of three human studies show significant alterations in the overall methylation of the sperm epigenome. One animal and one human study show associations between low folate intake and an increased risk of congenital malformations. CONCLUSIONS:This systematic review and meta-analysis shows evidence of associations between paternal folate status and sperm quality, fertility, congenital malformations, and placental weight.
Low paternal dietary folate alters the mouse sperm epigenome and is associated with negative pregnancy outcomes.
Lambrot R,Xu C,Saint-Phar S,Chountalos G,Cohen T,Paquet M,Suderman M,Hallett M,Kimmins S
Epidemiological studies suggest that a father's diet can influence offspring health. A proposed mechanism for paternal transmission of environmental information is via the sperm epigenome. The epigenome includes heritable information such as DNA methylation. We hypothesize that the dietary supply of methyl donors will alter epigenetic reprogramming in sperm. Here we feed male mice either a folate-deficient or folate-sufficient diet throughout life. Paternal folate deficiency is associated with increased birth defects in the offspring, which include craniofacial and musculoskeletal malformations. Genome-wide DNA methylation analysis and the subsequent functional analysis identify differential methylation in sperm of genes implicated in development, chronic diseases such as cancer, diabetes, autism and schizophrenia. While >300 genes are differentially expressed in offspring placenta, only two correspond to genes with differential methylation in sperm. This model suggests epigenetic transmission may involve sperm histone H3 methylation or DNA methylation and that adequate paternal dietary folate is essential for offspring health.
Parental smoking. Its effects on fetus and child health.
de Haas J H
European journal of obstetrics, gynecology, and reproductive biology
Smoking is a risk factor in pregnancy. Maternal smoking reduces the birthweight by 150-250 g (dose-response relationship), shifting the birthweight (and length) distribution to the left. Reduction of birthweight without shortening of gestation creates a group of small-for-date babies. Intrauterine hypoxia seems responsible for the growth retardation in smokers' babies as in babies of mothers living at high altitudes. Cigarette smoking of the mother affects fetal oxygenation, due to high levels of COHb in the blood of both mother and child. This observation is strongly supported by animal experiments. The total of (abortions), stillbirths, early and late neonatal mortality (especially stillbirths) is higher in babies of smoking than in those of nonsmoking mothers and highest among the poor. Approximately 5% of all stillbirths and neonatal deaths must be attributed to the increased mortality risk for the infant of mothers who smoke during the second half of pregnancy. Pregnancies of smoking mothers show about the same increase in infant wastage as pregnancies at high altitudes. The babies of smoking mothers show little excess of congenital malformations, if any. The placenta coefficient is increased. This symptom of compensatory placental hypertrophy cannot avert some impairment of fetal nutrition. There is less preeclamptic toxemia in smokers than in nonsmokers, but a higher incidence of antepartum hemorrhage and placental separation. Concerning long-term effects, smoking during pregnancy seems to be associated with a slight impairment of mental and physical growth. When the mother is nonsmoker and the father smokes more than ten cigarettes daily, an increase in perinatal mortality seems probable. Smoke aggravates the asthma of children in about two-thirds of those whose parents smoke. Healthy children of smokers are sick more frequently (primarily respiratory illness) than those of nonsmokers. Smoking parents and teachers stimulate their children and pupils to start smoking. Once smokers children may remain smokers. From the polemics on cause (smoking) and association (smoker) regarding the effects of parental smoking on the health of the fetus, the conclusion must be that health workers involved in obstetrics have great responsibilities in the antismoking campaign.
Placental abruption and perinatal death.
Kyrklund-Blomberg N B,Gennser G,Cnattingius S
Paediatric and perinatal epidemiology
Studies of risk factors for abruptio placentae (AP) are partly conflicting and studies of risk factors for perinatal death in these pregnancies are scarce. Using the population-based Swedish Birth Registry from 1987 to 1993, we were able to study these risks in 795,459 singleton pregnancies. Logistic regression analysis was used to estimate odds ratios (OR) for risk of AP and risk of perinatal death in pregnancies with and without AP. Risk factors for AP were: age, primiparity, high parity, not cohabiting with infant's father, low education, smoking, infertility, pregestational diabetes, essential hypertension, pregnancy-induced hypertensive diseases, preterm premature rupture of membranes, preterm birth and small-for-gestational-age (SGA) births. Risk factors for perinatal death in pregnancies with placental abruption were smoking (1--9 and > or =10 cigarettes/day; OR 1.4 and 1.7 respectively), severe pre-eclampsia (OR 2.0) and SGA (OR 1.9), whereas in pregnancies without abruption, risks were also increased in maternal age > or =35 years, primiparity, infertility, essential hypertension and pregestational diabetes. These findings support the theory that, in cases of AP, a general impairment of the placenta and/or a defect placentation may be fatal.
Diagnosis and management of neonatal alloimmune thrombocytopenia.
Arnold Donald M,Smith James W,Kelton John G
Transfusion medicine reviews
Neonatal alloimmune thrombocytopenia (NAT) is a life-threatening bleeding disorder caused by maternal platelet antibodies produced in response to fetal platelet antigens inherited from the father. Antiplatelet antibodies cross the placenta and cause destruction of fetal platelets, leading to severe thrombocytopenia, and potentially bleeding, including fatal intracerebral hemorrhage. Incompatibilities between maternal and fetal platelets for the human platelet antigen 1a (previously called PL(A1)) account for most of the patients with NAT, but other antigens are commonly implicated. Diagnostic testing for NAT involves genotyping of maternal, paternal, and sometimes fetal DNA; platelet antigen phenotyping; and maternal platelet antibody investigations using specialized platelet glycoprotein specific assays. The management of women and infants at risk for NAT remains largely empiric; and mounting evidence points to prohibitive risks of invasive procedures such as fetal blood sampling and intrauterine platelet transfusions, except in rare circumstances. Improvements in our understanding of the pathophysiology of NAT, and of clinical and laboratory predictors of severity, may help develop better treatments and improve our ability to identify mothers at risk.
Genomic duplication in the 19q13.42 imprinted region identified as a new genetic cause of intrauterine growth restriction.
Petre Graciane,Lorès Patrick,Sartelet Hervé,Truffot Aurélie,Poreau Brice,Brandeis Sandrine,Martinez Guillaume,Satre Véronique,Harbuz Radu,Ray Pierre F,Amblard Florence,Devillard Françoise,Vieville Gaëlle,Berger Francois,Jouk Pierre-Simon,Vaiman Daniel,Touré Aminata,Coutton Charles,Bidart Marie
We report findings from a male fetus of 26 weeks' gestational age with severe isolated intrauterine growth restriction (IUGR). Chromosomal microarray analysis (CMA) on amniotic fluid cells revealed a 1.06-Mb duplication in 19q13.42 inherited from the healthy father. This duplication contains 34 genes including ZNF331, a gene encoding a zinc-finger protein specifically imprinted (paternally expressed) in the placenta. Study of the ZNF331 promoter by methylation-specific-multiplex ligation-dependent probe amplification showed that the duplicated allele was not methylated in the fetus unlike in the father's genome, suggesting both copies of the ZNF331 gene are expressed in the fetus. The anti-ZNF331 immunohistochemical analysis confirmed that ZNF331 was expressed at higher levels in renal and placental tissues from this fetus compared to controls. Interestingly, ZNF331 expression levels in the placenta have previously been reported to inversely correlate with fetal growth parameters. The original observation presented in this report showed that duplication of ZNF331 could be a novel genetic cause of isolated IUGR and underlines the usefulness of CMA to investigate the genetic causes of isolated severe IUGR.
Prior adverse pregnancy outcome and the risk of stillbirth.
Rasmussen Svein,Irgens Lorentz M,Skjaerven Rolv,Melve Kari Klungsøyr
Obstetrics and gynecology
OBJECTIVE:To estimate whether a history of fetal growth restriction, abruptio placentae, preeclampsia, or live preterm birth is associated with excess risk of stillbirth in a subsequent pregnancy. We also estimated the maternal and paternal contributions to such effects. METHODS:This was a population-based cohort study from 1967 to 2005. Pairs of first and second, second and third, third and fourth, and fourth and fifth births were identified among all births from the Medical Birth Registry of Norway; 747,221 pairs with the same parents, 51,708 with the same mother and different father, and 65,602 with the same father and different mother. The associations of gestational age categories (22-27, 28-32, 33-36, and at or above 37 weeks), small for gestational age (SGA), preeclampsia, and abruptio placenta in the first pregnancy with stillbirth and late abortion in the second were assessed by odds ratios (ORs) obtained by logistic regression. RESULTS:The baseline rate of stillbirth during the study period was 1.0% of all births from 16 weeks of gestation. After births with gestational age 22-27, 28-32, and 33-36 weeks of gestation, stillbirth was six, three and two times more likely to occur than after a term birth (OR 5.7, 95% confidence interval [CI] 4.2-7.6; OR 2.6, 95% CI 2.1-3.3; and OR 1.7, 95% CI 1.5-1.9, respectively). Odds ratios of stillbirth subsequent to pregnancies with SGA, preeclampsia, and abruptio placentae were 1.7 (95% CI 1.6-1.9), 1.6 (95% CI 1.5-1.9), and 2.8 (95% CI 2.2-3.5), respectively, and increased with severity of the conditions. Gestational age below 33 weeks with preeclampsia or SGA carried 6-9 and 6-13-fold effects on later stillbirth, respectively. Men who fathered a pregnancy with preterm preeclampsia were significantly more likely to father a stillbirth in another woman (OR 2.4, 95% CI 1.1-5.5). CONCLUSION:Live preterm birth, fetal growth restriction, preeclampsia, and abruptio placenta are strongly associated with later stillbirth. LEVEL OF EVIDENCE:II.
The paternal polymorphism rs5370 in the EDN1 gene decreases the risk of preeclampsia.
Galaviz-Hernandez Carlos,Arámbula-Meraz Eliakym,Medina-Bastidas Diana,Sosa-Macías Martha,Lazalde-Ramos Blanca P,Ortega-Chávez Margarita,Hernandez-García Lorena
OBJECTIVE:To evaluate whether the maternal, paternal or the combined maternal/paternal contribution of SNP rs5370 of the EDN1 gene is associated with preeclampsia and drove its expression in placenta. STUDY DESIGN:This case-control study included 61 preeclamptic patients and their partners and 49 healthy pregnant women and their partners. The population was sub-divided into three groups: women-only, men-only and combined (women/men). The analysis included genotyping of rs5370 in mothers and fathers and evaluating the expression profile of the EDN1 gene in placenta. Comparisons of categorical variables were performed using chi-square and/or Fisher's exact tests. The intergroup comparisons were analysed with the Mann-Whitney U test. The association between the polymorphism and the disease was evaluated through multivariate regression analysis. Spearman's correlation was performed to test the relationship between pre-gestational history and clinical features of the affected patients with EDN1 gene expression. RESULTS:The analysis of paternal risk factors associated with preeclampsia revealed no differences between groups. A negative association between SNP rs5370 and preeclampsia was found in men group (OR 0.42; CI 95% 0.18-0.94, p=0.034) but not in women or combined groups. The adjustment for paternal protective factors increased the observed negative association, and the opposite was observed in the presence of paternal risk factors. The expression of the EDN1 gene in the placenta was significantly higher in the group of cases and was not associated with the rs5370 polymorphism. CONCLUSION:The paternal rs5370 polymorphism decreases the risk for preeclampsia and is not associated with placental expression of the EDN1 gene.
Exposure of pregnant mice to chlorpyrifos-methyl alters embryonic H19 gene methylation patterns.
Shin Hyo-Sook,Seo Jong-Hun,Jeong Sang-Hee,Park Sung-Won,Park Youngil,Son Seong-Wan,Kim Jin Suk,Kang Hwan-Goo
The aim of this study was to identify whether chlorpyrifos methyl (CPM) exposure during pregnancy leads to changes in the methylation patterns of H19 gene. CPM 4, 20, 100 mg/kg bw/day was administered to 4 pregnant mice per group between 7 and 12 days post coitum (d.p.c.). Pregnant mice were killed at 13 d.p.c. The genomic methylation in primordial germ cells (PGCs) and fetal organs (the liver, intestine, and placenta) was examined. Four polymorphism sites in the H19 alleles of maternal (C57BL/6J) and paternal (CAST/Ei) alleles were identified at nucleotide position 1407, 1485, 1566, and 1654. The methylation patterns of 17 CpG sites were analyzed. The methylation level in male and female PGCs was not altered by CPM treatment in the maternal allele H19. The methylation level of the paternal H19 allele was altered in only male PGCs in response to the CPM treatment. The methylation level at a binding site for the transcriptional regulator CTCF2 was higher than that at the CTCF1 binding site in all CPM-treated groups. In the placenta, the aggregate methylation level of H19 was 56.89%in control group. But, those levels were ranged from 47.7% to 49.89% after treatment with increasing doses of CPM. H19 gene from the liver and intestine of 13 d.p.c. fetuses treated with CPM was hypomethylated as compared with controls, although H19 mRNA expression was unaltered. In the placenta, H19 expression was slightly increased in the CPM-treated group, although not significantly. IGF2 expression levels were not significantly changed in the placenta. In conclusion, CPM exposure during pregnancy alters the methylation status of the H19 gene in PGCs and embryonic tissues. We infer that these alterations are likely related to changes in DNA demethylase activity.
Placental mesenchymal dysplasia and fetal renal-hepatic-pancreatic dysplasia: androgenetic-biparental mosaicism and pathogenesis of an autosomal recessive disorder.
Kapur Raj P,Cole Bonnie,Zhang Min,Lin Jingxian,Fligner Corinne L
Pediatric and developmental pathology : the official journal of the Society for Pediatric Pathology and the Paediatric Pathology Society
Androgenetic-biparental mosaicism (ABM) denotes an embryo in which a subset of cells contains a diploid chromosomal complement derived entirely from the father. Such embryos have a high incidence of placental mesenchymal dysplasia (PMD) and paternal imprinting disorders because the androgenetic cells have pangenomic paternal uniparental disomy. Uniparental disomy also poses a theoretical risk for paternally transmitted autosomal recessive disorders, if both chromosomes of each autosomal pair are identical (isodisomy). We present the 1st example of a recessive disorder, renal-hepatic-pancreatic dysplasia, in a pregnancy complicated by PMD and ABM. Androgenetic-biparental mosaicism was demonstrated in fetal DNA, extracted from multiple organs, by quantitative polymerase chain reaction-based methods that detected allelic imbalances at the differentially methylated SNRPN locus (chromosome 15); polymorphic short tandem repeat microsatellite markers located on chromosomes 4, 7, 8, 13, 18, and 21; and single nucleotide polymorphisms on chromosomes 1 and 19. Laser capture microdissection was performed to isolate specific placental and renal cell populations and document selective enrichment of androgenetic cells in the stroma of PMD and the epithelium of renal cysts. Mutational analysis of coding sequences did not reveal any mutations in NPHP3, a ciliopathy gene implicated in some cases of renal-hepatic-pancreatic dysplasia. Nonetheless, the fetal phenotype and laser capture data support the model of a paternally transmitted autosomal recessive disorder, which occurred because of ABM.
Gene expression and epigenetic aberrations in F1-placentas fathered by obese males.
Mitchell Megan,Strick Reiner,Strissel Pamela L,Dittrich Ralf,McPherson Nicole O,Lane Michelle,Pliushch Galyna,Potabattula Ramya,Haaf Thomas,El Hajj Nady
Molecular reproduction and development
Gene expression and/or epigenetic deregulation may have consequences for sperm and blastocysts, as well as for the placenta, together potentially contributing to problems observed in offspring. We previously demonstrated specific perturbations of fertilization, blastocyst formation, implantation, as well as aberrant glucose metabolism and adiposity in offspring using a mouse model of paternal obesity. The current investigation analyzed gene expression and methylation of specific CpG residues in F1 placentas of pregnancies fathered by obese and normal-weight male mice, using real-time PCR and bisulfite pyrosequencing. Our aim was to determine if paternal obesity deregulated placental gene expression and DNA methylation when compared to normal-weight males. Gene methylation of sperm DNA was analyzed and compared to placentas to address epigenetic transmission. Of the 10 paternally expressed genes (Pegs), 11 genes important for development and transport of nutrients, and the long-terminal repeat Intracisternal A particle (IAP) elements, derived from a member of the class II endogenous retroviral gene family, we observed a significant effect of paternal diet-induced obesity on deregulated expression of Peg3, Peg9, Peg10, and the nutrient transporter gene Slc38a2, and aberrant DNA methylation of the Peg9 promoter in F1 placental tissue. Epigenetic changes in Peg9 were also found in sperm from obese fathers. We therefore propose that paternal obesity renders changes in gene expression and/or methylation throughout the placental genome, which could contribute to the reproductive problems related to fertility and to the metabolic, long-term health impact on offspring.
Placental weight in relation to maternal and paternal preconception and prenatal urinary phthalate metabolite concentrations among subfertile couples.
Mustieles Vicente,Mínguez-Alarcón Lidia,Christou George,Ford Jennifer B,Dimitriadis Irene,Hauser Russ,Souter Irene,Messerlian Carmen,
INTRODUCTION:Phthalates are known reproductive toxicants that reduce placental and fetal weight in experimental animal studies. Although phthalate exposure has been associated with reduced birth weight in humans, there is limited epidemiologic evidence on whether the placenta is also affected. OBJECTIVE:To assess whether maternal and paternal preconception and prenatal urinary phthalate metabolite concentrations are associated with placental weight, and the birth weight: placental weight (BW:PW) ratio among singletons conceived by subfertile couples. METHODS:The present analysis included 132 mothers and 68 fathers, and their corresponding 132 singletons recruited in an academic hospital fertility center in Boston, Massachusetts. Urinary concentrations of eleven phthalate metabolites were measured and averaged in multiple paternal (n = 196) and maternal (n = 596) preconception, and maternal prenatal (n = 328) samples. Placental weight and birth weight (grams) were abstracted from delivery records, and the BW:PW was calculated. We estimated the association of natural log-phthalate metabolite concentrations across windows of exposure with placental weight and the BW:PW ratio using multivariable linear regression models, adjusting for a priori covariates. RESULTS:In adjusted models, each log-unit increase in paternal urinary concentrations of the sum of di-(2-ethylhexyl) phthalate (ΣDEHP) metabolites was associated with a 24 g (95% CI: -48, -1) decrease in placental weight. We also observed a significant negative association between maternal preconception monoethyl phthalate (MEP) metabolite concentrations and the BW:PW ratio (β = -0.26; 95%CI: -0.49, -0.04). Additionally, each log-unit increase in prenatal MEP metabolite concentrations was associated with a 24 g (95% CI: -41, -7) decrease in placental weight. CONCLUSIONS:Our results suggest that certain paternal and maternal urinary phthalate metabolites may affect placental weight and the BW:PW ratio. However, given the small sample size within a subfertile cohort and the novelty of these findings, more studies are needed to confirm the present results.
Fetal growth and preterm birth in children exposed to maternal or paternal rheumatoid arthritis: a nationwide cohort study.
Rom Ane L,Wu Chun S,Olsen Jørn,Kjaergaard Hanne,Jawaheer Damini,Hetland Merete L,Vestergaard Mogens,Mørch Lina S
Arthritis & rheumatology (Hoboken, N.J.)
OBJECTIVE:To assess indicators of fetal growth and risk of preterm birth in children of parents with rheumatoid arthritis (RA). METHODS:Through linkage of Danish national registries, we identified all children born in Denmark between 1977 and 2008. We used general linear regression models to estimate mean differences in indicators of fetal growth among children with a parent with RA compared to unexposed children. Odds ratios (ORs) and 95% confidence intervals (95% CIs) of preterm birth were calculated using a logistic regression model. RESULTS:Of the 1,917,723 children included, a total of 13,556 children were exposed to maternal RA or maternal preclinical RA. Children exposed to maternal RA (n = 2,101) had approximately similar length, head circumference, and abdominal circumference at birth compared with children of mothers without RA. Birth weight was 87 gm lower (mean difference -87.04 gm [95% CI -111.23, -62.84]) and placenta weight was 14 gm lower (-13.45 gm [95% CI -21.46, -5.43]) than those in children of mothers without RA. Rather similar results were found in children exposed to maternal preclinical RA (n = 11,455). Compared with unexposed children, a higher risk of preterm birth was found in children exposed to maternal RA (OR 1.48 [95% CI 1.20, 1.84]) and preclinical RA (OR 1.32 [95% CI 1.07, 1.64]). No associations were found with paternal RA. CONCLUSION:Children exposed to either maternal RA or maternal preclinical RA are more often born preterm. However, indicators of fetal growth measured at birth were only slightly lower than those in unexposed children.
Paternal diet-induced obesity retards early mouse embryo development, mitochondrial activity and pregnancy health.
Binder Natalie K,Hannan Natalie J,Gardner David K
Worldwide, 48% of adult males are overweight or obese. An association between infertility and excessive body weight is now accepted, although focus remains primarily on females. It has been shown that parental obesity results in compromised embryo development, disproportionate changes in embryo metabolism and reduced blastocyst cell number. The aim of this study was to determine whether paternal obesity has negative effects on the resultant embryo. Specifically, using in vitro fertilisation (IVF), we wanted to isolate the functional effects of obesity on sperm by examining the subsequent embryo both pre- and post-implantation. Epididymal sperm was collected from age matched normal and obese C57BL/6 mice and cryopreserved for subsequent IVF with oocytes collected from Swiss females (normal diet/weight). Obesity was induced in male mice by feeding a high fat diet of 22% fat for 10 weeks. Resultant embryos were cultured individually and development monitored using time-lapse microscopy. Paternal obesity resulted in a significant delay in preimplantation embryo development as early as syngamy (P<0.05). Metabolic parameters were measured across key developmental stages, demonstrating significant reduction in mitochondrial membrane potential (P<0.01). Blastocysts were stained to determine trophectoderm (TE) and inner cell mass (ICM) cell numbers, revealing significant differences in the ratio of cell allocation to TE and ICM lineages (P<0.01). Functional studies examining blastocyst attachment, growth and implantation demonstrated that blastocysts derived from sperm of obese males displayed significantly reduced outgrowth on fibronectin in vitro (P<0.05) and retarded fetal development in vivo following embryo transfer (P<0.05). Taken together, these data clearly demonstrate that paternal obesity has significant negative effects on the embryo at a variety of key early developmental stages, resulting in delayed development, reduced placental size and smaller offspring.
The many faces of human leukocyte antigen-G: relevance to the fate of pregnancy.
Dahl Mette,Djurisic Snezana,Hviid Thomas Vauvert F
Journal of immunology research
Pregnancy is an immunological paradox, where fetal antigens encoded by polymorphic genes inherited from the father do not provoke a maternal immune response. The fetus is not rejected as it would be theorized according to principles of tissue transplantation. A major contribution to fetal tolerance is the human leukocyte antigen (HLA)-G, a nonclassical HLA protein displaying limited polymorphism, restricted tissue distribution, and a unique alternative splice pattern. HLA-G is primarily expressed in placenta and plays multifaceted roles during pregnancy, both as a soluble and a membrane-bound molecule. Its immunomodulatory functions involve interactions with different immune cells and possibly regulation of cell migration during placental development. Recent findings include HLA-G contributions from the father and the fetus itself. Much effort has been put into clarifying the role of HLA-G during pregnancy and pregnancy complications, such as preeclampsia, recurrent spontaneous abortions, and subfertility or infertility. This review aims to clarify the multifunctional role of HLA-G in pregnancy-related disorders by focusing on genetic variation, differences in mRNA stability between HLA-G alleles, differences in HLA-G isoform expression, and possible differences in functional activity. Furthermore, we highlight important observations regarding HLA-G genetics and expression in preeclampsia that future research should address.
Feto-placental atherosclerotic lesions in intrauterine fetal demise: role of parental cigarette smoking.
Mecchia D,Lavezzi A M,Mauri M,Matturri L
The open cardiovascular medicine journal
The atherogenic effect of cigarette smoking is already recognizable in coronary arteries of fetuses in the last gestational weeks. In this study we analyzed the atherogenic effect of mother's and father's smoking habit on coronary arteries and even on adnexa of 30 human fresh fetuses died from 32 to 41 gestational weeks. In 12 cases only the mothers of the victims were cigarette smokers, in 7 cases only the fathers were smokers, whereas in 11 cases nobody smoked.We observed pre-atherosclerotic and initial atherosclerotic lesions of the adnexa in 21 cases, of which 11 cases had only mother smokers and 6 cases only father smokers. The atherogenic effect is statistically significant in both smoker groups, but stronger in maternal one. The atherosclerotic lesions found in umbilical and placental arteries are similar to those described in fetal coronary arteries: thickening of the arterial walls caused by proliferation and migration of the smooth muscle cells of the tunica media with loss of polarity and infiltration of the subendothelial connective tissue.
Paternal Determinants in Preeclampsia.
Galaviz-Hernandez Carlos,Sosa-Macias Martha,Teran Enrique,Garcia-Ortiz Jose Elias,Lazalde-Ramos Blanca Patricia
Frontiers in physiology
Preeclampsia is a condition associated with high rates of maternal-fetal morbidity and mortality. It usually occurs in 3-10% of nulliparous women and 18% of previously affected women. Different lines of evidence have demonstrated the role of the father in the onset of preeclampsia. The placenta is the cornerstone of preeclampsia and poses important paternal genetic determinants; in fact, the existence of a "paternal antigen" has been proposed. Nulliparity is a well-known risk factor. Change of partner to a woman without history of preeclampsia increases the risk; however, this change decreases in women with history of the condition. High interval between pregnancies, short sexual intercourse before pregnancy, and conception by intracytoplasmic sperm injection suggest a limited exposure to the so-called paternal antigen. A man who was born from a mother with preeclampsia also increases the risk to his partner. Not only maternal but also paternal obesity is a risk factor for preeclampsia. Fetal HLA-G variants from the father increased the immune incompatibility with the mother and are also significantly associated with preeclampsia in multigravida pregnancies. An analysis of a group of Swedish pregnant women showed that the risk for preeclampsia is attributable to paternal factors in 13% of cases, which could be related to genetic interactions with maternal genetic factors. This review aimed to evaluate the evidences of the father's contribution to the onset of preeclampsia and determine the importance of including them in future studies.
Genomic imprinting, action, and interaction of maternal and fetal genomes.
Keverne Eric B
Proceedings of the National Academy of Sciences of the United States of America
Mammalian viviparity (intrauterine development of the fetus) introduced a new dimension to brain development, with the fetal hypothalamus and fetal placenta developing at a time when the fetal placenta engages hypothalamic structures of the maternal generation. Such transgenerational interactions provide a basis for ensuring optimal maternalism in the next generation. This success has depended on genomic imprinting and a biased role of the matriline. Maternal methylation imprints determine parent of origin expression of genes fundamental to both placental and hypothalamic development. The matriline takes a further leading role for transgenerational reprogramming of these imprints. Developmental errors are minimized by the tight control that imprinted genes have on regulation of downstream evolutionary expanded gene families important for placental and hypothalamic development. Imprinted genes themselves have undergone purifying selection, providing a framework of stability for in utero development with most growth variance occurring postnatally. Mothers, not fathers, take the lead in the endocrinological and behavior adaptations that nurture, feed, and protect the infant. In utero coadaptive development of the placenta and hypothalamus has thus required a concomitant development to ensure male masculinization. Only placental male mammals evolved the sex determining SRY, which activates Sox9 for testes formation. SRY is a hybrid gene of Dgcr8 expressed in the developing placenta and Sox3 expressed in hypothalamic development. This hybridization of genes that take their origin from the placenta and hypothalamus has enabled critical in utero timing for the development of fetal Leydig cells, and hence testosterone production for hypothalamic masculinization.
Placenta-mediated pregnancy complications are not associated with fetal or paternal factor V Leiden mutation.
Nevalainen Jaana,Ignatius Jaakko,Savolainen E-R,Ryynanen Markku,Jarvenpaa Jouko
European journal of obstetrics, gynecology, and reproductive biology
OBJECTIVE:Maternal thrombophilia is a risk factor for adverse pregnancy outcomes. The aim of this study was to elucidate the controversial role of fetal and paternal thrombophilia in the development of severe placenta-mediated pregnancy complications. STUDY DESIGN:The study group comprised 126 mothers, 72 fetuses and 58 fathers. 111 mothers, 50 fetuses and 91 fathers acted as controls. 106 couples were selected to study the thrombophilias of paternal inheritance, 58 from the study group and 48 from the control group. The prevalence of factor V Leiden mutation, prothrombin G20210 A mutation and homozygous 10-methylenetetrahydrofolate reductase C677 T mutations were compared between the study and control groups to study whether maternal, fetal or paternal thrombophilias increase the risk of severe preeclampsia, intrauterine growth restriction, placental abruption and stillbirth. RESULTS:The total prevalence of fetal thrombophilic mutations was 8.3% in the study group and 14.0% in the control group. Paternal prevalence of thrombophilic mutations was 6.8% and 4.3%, respectively. There were no statistical differences between fetal or paternal thrombophilic mutations between the study and control groups. CONCLUSION:Fetal or paternal factor V Leiden mutation is not associated with severe placenta-mediated pregnancy complications.
Morphine Exposure and Enhanced Depression-like Behaviour Confronting Chronic Stress in Adult Male Offspring Rat.
Torkaman-Boutorabi Anahita,Seifi Fereshteh,Akbarabadi Ardeshir,Toolee Heidar,Sadat-Shirazi Mitra-Sadat,Vousooghi Nasim,Zarrindast Mohammad-Reza
Basic and clinical neuroscience
Introduction:Opioid addiction is an important concern in the World. Reports demonstrate that substance use disorder could influence genetic and environmental factors, and children of addicts have a higher rate of psychopathology. In this study, we investigated depression-like behavior among offspring of morphine-exposed rat parents. Methods:Adult male and female Wistar rats received morphine for 21 consecutive days and then let them were free of drugs for ten days. Offspring of these rats were divided into three distinct groups: maternal morphine-exposed, paternal morphine-exposed, and both maternal and paternal morphine-exposed. We used sucrose preference and Forced Swim Test (FST) to measure depression-like behavior. Also, we induced chronic mild stress using repeated corticosterone injection and evaluated depression-like behavior in offspring of morphine-exposed parents compared with offspring of healthy ones. Results:Results indicated that depression-like behaviors in the offspring of morphine-exposed rats were higher than those in the offspring of the control group in confronting with chronic mild stress. Additionally, mild chronic stress can produce an exaggerated effect on depression-like behavior in offspring of the morphine-exposed parent(s) compared with those of the control group. Conclusion:Our data support the previous hypothesis that the depression rate is higher in the children of addicts. We verified that even when mother or father was clean of opioid in the time of gestation, their children would be susceptible to depression. Dysregulation of hypothalamic-pituitary-adrenal axis and changing in neuronal features in the hippocampus increased depression-like behavior in the offspring of morphine-exposure parents.
Epigenetics as a Driver of Developmental Origins of Health and Disease: Did We Forget the Fathers?
BioEssays : news and reviews in molecular, cellular and developmental biology
What are the effects of our environment on human development and the next generation? Numerous studies have provided ample evidence that a healthy environment and lifestyle of the mother is important for her offspring. Biological mechanisms underlying these environmental influences have been proposed to involve alterations in the epigenome. Is there enough evidence to suggest a similar contribution from the part of the father? Animal models provide proof of a transgenerational epigenetic effect through the paternal germ line, but can this be translated to humans? To date, literature on fathers is scarce. Human studies do not always incorporate appropriate tools to evaluate paternal influences or epigenetic effects. In reviewing the literature, I stress the need to explore and recognize paternal contributions to offspring's health within the Developmental Origins of Health and Disease hypothesis, and coin this new concept the Paternal Origins of Health and Disease paradigm (POHaD). A better understanding of preconceptional origins of disease through the totality of paternal exposures, or the paternal exposome, will provide evidence-based public health recommendations for future fathers.
Paternal nicotine exposure in rats produces long-lasting neurobehavioral effects in the offspring.
Hawkey Andrew B,White Hannah,Pippen Erica,Greengrove Eva,Rezvani Amir H,Murphy Susan K,Levin Edward D
Neurotoxicology and teratology
Studies of intergenerational effects of parental chemical exposure have principally focused on maternal exposure, particularly for studies of adverse neurobehavioral consequences on the offspring. Maternal nicotine exposure has long been known to cause adverse neurobehavioral effects on the offspring. However, paternal toxicant exposure has also been found to cause neurobehavioral toxicity in their offspring. Recent work suggests that paternal nicotine exposure can have epigenetic effects, although it remains unclear whether such changes lead to neurobehavioral effects. In the current study, we investigated the effects of paternal nicotine exposure on neurobehavioral development of their offspring. Male Sprague-Dawley rats were exposed to 0 or 2 mg/kg/day nicotine (sc) for 56 consecutive days with two consecutive 2ML4 osmotic minipumps. Following treatment, these males were mated with drug-naïve female rats. Offspring of both sexes were tested in a behavioral battery to assess locomotion, emotional function and cognition. Paternal nicotine exposure did not impact offspring viability, health or growth. However, behavioral function of the offspring was significantly altered by paternal nicotine exposure. Male offspring with paternal nicotine exposure exhibited locomotor hyperactivity in the Figure-8 apparatus when tested during adolescence. When retested in adulthood and regardless of sex, offspring of the nicotine exposed father showed significantly reduced habituation of locomotor activity over the course of the session. Compared to controls, female offspring of nicotine-exposed fathers showed significantly reduced response latency in the radial arm maze test. In addition to locomotor hyperactivity, the offspring of nicotine-exposed fathers also showed significantly diminished habituation in the novel object recognition test. These results indicate that chronic paternal nicotine exposure can impact the behavior of offspring, producing locomotor hyperactivity and impaired habituation.
Paternal age is affected by genetic abnormalities, perinatal complications and mental health of the offspring.
Janeczko Dominika,Hołowczuk Magdalena,Orzeł Anna,Klatka Barbara,Semczuk Andrzej
Infertility and fecundity problems concern 10-18% of partners in their reproductive years compromising around one million females and males in Poland. Research and analysis of factors that affect male fertility are limited, especially, regarding the age of the father and determining the age at which quality of semen decreases. Age of the father has greater impact than maternal age, on cases of sporadic autosomal dominant congenital diseases such as Apert, Crouzon, Pfeiffer, Noonan and Costello syndromes, multiple endocrine neoplasia (types 2A and 2B) and achondroplasia. However, there are only a few reports taking paternal advanced age into consideration for pre-mature birth, low Apgar scores or admission to a neonatal intensive care department. Paternal age increases the frequency of congenital diseases such as heart malformations as well as oral, palate and lip cleft. Moreover, mental disorders (autism, schizophrenia, bipolar disorder, low IQ level as well as ADHD) also occur more frequently in advanced father's age. Advanced paternal age is defined differently in every research. It depends on disorders in offspring we are talking about. Paternal age has an impact on child's health and development and it is as significant as maternal age, when it comes to reproductive matters.
Paternal cholestasis exacerbates obesity-associated hypertension in male offspring but is prevented by paternal ursodeoxycholic acid treatment.
Pataia Vanessa,Papacleovoulou Georgia,Nikolova Vanya,Samuelsson Anne-Maj,Chambers Stephanie,Jansen Eugene,Taylor Paul D,Poston Lucilla,Williamson Catherine
International journal of obesity (2005)
BACKGROUND:Obesity is a heterogeneous phenotype and risk associations to non-communicable diseases such as cardiovascular disease and type 2 diabetes are influenced by several factors. The paternal metabolic status at the time of conception influences offspring susceptibility to developing obesity and adiposity-associated cardiometabolic disease. Cholestatic liver diseases are characterized by raised circulating serum bile acid levels and dyslipidemia, and are commonly treated with ursodeoxycholic acid (UDCA). We hypothesized that paternal cholestasis alters offspring susceptibility to developing obesity and adiposity-associated cardiometabolic disease and that this may be modified by paternal UDCA treatment. METHODS:Cholestasis was induced in male C57BL/6 mice with a 0.5% cholic acid (CA)-supplemented diet for 10 weeks prior to mating with normal chow (NC)-fed females. Offspring of cholestatic and NC-fed fathers were fed either a NC diet or challenged with an obesogenic 'western diet' (WD) from 12 weeks of age. Offspring body weight and cardiometabolic function were assessed, and the impact of treatment of paternal cholestasis with UDCA was evaluated. RESULTS:Male offspring (18 weeks old) of cholestatic fathers challenged with WD had raised fasting insulin, hepatic triglyceride content and serum cholesterol levels compared to diet-matched controls. At 25-29 weeks of age, WD-fed male offspring of cholestatic fathers had higher systolic and diastolic blood pressure than controls and this was prevented by paternal UDCA treatment. In contrast, WD-challenged female offspring of cholestatic fathers showed improved glucose tolerance compared to controls. CONCLUSIONS:We demonstrated in our model of paternal cholestasis that offspring susceptibility to adiposity-associated cardiometabolic disease is affected in a sex-specific manner and paternal UDCA treatment had a protective effect against hypertension in the obese male offspring. The most prevalent human cholestatic conditions are primary sclerosing cholangitis and primary biliary cholangitis. These findings are of clinical relevance to children of men with these conditions.
Paternal factors in neurodevelopmental toxicology: THC exposure of male rats causes long-lasting neurobehavioral effects in their offspring.
Holloway Zade R,Hawkey Andrew B,Pippin Erica,White Hannah,Wells Corinne,Kenou Bruny,Rezvani Amir H,Murphy Susan K,Levin Edward D
The potential health risks of cannabis are of growing concern, including effects on reproduction and development. Extensive research has investigated risks associated with maternal exposure to THC during gestation and its impacts on the development of offspring, but little research has been done regarding paternal THC exposure effects prior to conception. We have previously found that paternal THC exposure in rats causes changes in sperm methylation. In an initial study we also showed that a 12-day paternal THC exposure prior to conception alters locomotor activity and impairs cognitive function of their offspring. This study investigated the cross-generational effects of chronic paternal THC exposure in rats (0, 2, or 4 mg/kg/day SC for 28 days) prior to mating with drug naïve females. The offspring of THC-exposed male rats had significant alterations in locomotor activity and cognitive function. Specifically, during adolescence there was significant locomotor hyperactivity in the offspring of males exposed to 2 mg/kg/day of THC. During the novel object recognition task, the controls maintained their relative preference for the novel object across the duration of the ten-min session while the rats whose fathers received THC (2 mg/kg/day) showed a significantly greater drop-off in interest in the novel object during the second half of the session. Learning in the radial-arm maze was significantly delayed in the offspring of males exposed to 4 mg/kg/day of THC. This study shows that premating chronic paternal THC exposure at multiple dose regimens can cause long-lasting detrimental behavioral effects in their offspring, including abnormal locomotor activity and impaired cognitive function. Future studies should investigate the underlying mechanisms driving these aberrant developmental outcomes and seek to identify possible treatments of alleviation in the presence of paternal THC exposure.
Paternal developmental toxicant exposure is associated with epigenetic modulation of sperm and placental Pgr and Igf2 in a mouse model.
Ding Tianbing,Mokshagundam Shilpa,Rinaudo Paolo F,Osteen Kevin G,Bruner-Tran Kaylon L
Biology of reproduction
Preterm birth (PTB), parturition prior to 37 weeks' gestation, is the leading cause of neonatal mortality. The causes of spontaneous PTB are poorly understood; however, recent studies suggest that this condition may arise as a consequence of the parental fetal environment. Specifically, we previously demonstrated that developmental exposure of male mice (F1 animals) to the environmental endocrine disruptor 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was associated with reduced sperm quantity/quality in adulthood and control female partners frequently delivered preterm. Reproductive defects persisted in the F2 and F3 descendants, and spontaneous PTB was common. Reproductive changes in the F3 males, the first generation without direct TCDD exposure, suggest the occurrence of epigenetic alterations in the sperm, which have the potential to impact placental development. Herein, we conducted an epigenetic microarray analysis of control and F1 male-derived placentae, which identified 2171 differentially methylated regions, including the progesterone receptor (Pgr) and insulin-like growth factor (Igf2). To assess if Pgr and Igf2 DNA methylation changes were present in sperm and persist in future generations, we assessed methylation and expression of these genes in F1/F3 sperm and F3-derived placentae. Although alterations in methylation and gene expression were observed, in most tissues, only Pgr reached statistical significance. Despite the modest gene expression changes in Igf2, offspring of F1 and F3 males consistently exhibited IUGR. Taken together, our data indicate that paternal developmental TCDD exposure is associated with transgenerational placental dysfunction, suggesting epigenetic modifications within the sperm have occurred. An evaluation of additional genes and alternative epigenetic mechanisms is warranted.
Immunological Tolerance, Pregnancy, and Preeclampsia: The Roles of Semen Microbes and the Father.
Kenny Louise C,Kell Douglas B
Frontiers in medicine
Although it is widely considered, in many cases, to involve two separable stages (poor placentation followed by oxidative stress/inflammation), the precise originating causes of preeclampsia (PE) remain elusive. We have previously brought together some of the considerable evidence that a (dormant) microbial component is commonly a significant part of its etiology. However, apart from recognizing, consistent with this view, that the many inflammatory markers of PE are also increased in infection, we had little to say about immunity, whether innate or adaptive. In addition, we focused on the gut, oral and female urinary tract microbiomes as the main sources of the infection. We here marshall further evidence for an infectious component in PE, focusing on the immunological tolerance characteristic of pregnancy, and the well-established fact that increased exposure to the father's semen assists this immunological tolerance. As well as these benefits, however, semen is not sterile, microbial tolerance mechanisms may exist, and we also review the evidence that semen may be responsible for inoculating the developing conceptus (and maybe the placenta) with microbes, not all of which are benign. It is suggested that when they are not, this may be a significant cause of PE. A variety of epidemiological and other evidence is entirely consistent with this, not least correlations between semen infection, infertility and PE. Our view also leads to a series of other, testable predictions. Overall, we argue for a significant paternal role in the development of PE through microbial infection of the mother insemination.
Placental effects on the maternal brain revealed by disrupted placental gene expression in mouse hybrids.
Arévalo Lena,Campbell Polly
Proceedings. Biological sciences
The mammalian placenta is both the physical interface between mother and fetus, and the source of endocrine signals that target the maternal hypothalamus, priming females for parturition, lactation and motherhood. Despite the importance of this connection, the effects of altered placental signalling on the maternal brain are insufficiently studied. Here, we show that placental dysfunction alters gene expression in the maternal brain, with the potential to affect maternal behaviour. Using a cross between the house mouse and the Algerian mouse, in which hybrid placental development is abnormal, we sequenced late-gestation placental and maternal medial preoptic area transcriptomes and quantified differential expression and placenta-maternal brain co-expression between normal and hybrid pregnancies. The expression of and was significantly altered in the brains of females exposed to hybrid placentas. Most strikingly, expression patterns of placenta-specific gene families and in the brains of house mouse females carrying hybrid litters matched those of female Algerian mice, the paternal species in the cross. Our results indicate that the paternally derived placental genome can influence the expression of maternal-fetal communication genes, including placental hormones, suggesting an effect of the offspring's father on the mother's brain.
Paternal age, placental weight and placental to birthweight ratio: a population-based study of 590,835 pregnancies.
Strøm-Roum E M,Haavaldsen C,Tanbo T G,Eskild A
Human reproduction (Oxford, England)
STUDY QUESTION:Is the age of the father associated with placental weight or the ratio of placental weight to birthweight? SUMMARY ANSWER:Placental weight and placental to birthweight ratio increased according to increasing paternal age, also after adjustment for maternal age. WHAT IS KNOWN ALREADY:High paternal age and also high placental to birthweight ratio have been associated with adverse pregnancy outcome. STUDY DESIGN, SIZE AND DURATION:We performed a population-based study and included all singleton births after 22 weeks of gestation in the Medical Birth Registry of Norway (n = 590,835) during the years 1999-2009. PARTICIPANTS/MATERIALS, SETTING, METHODS:We compared mean placental weight and placental to birthweight ratio between paternal age groups. The association of paternal age with placental weight was estimated by linear regression analyses, and adjustments were made for maternal age, birthweight, parity, offspring sex, gestational age at birth, maternal smoking, pre-eclampsia, maternal diabetes mellitus and pregnancy after assisted reproductive technology (ART). MAIN RESULTS AND THE ROLE OF CHANCE:In pregnancies with fathers aged 20-24 years old, the mean placental weight was 656.2 g [standard deviation (SD) 142.8], whereas it was 677.8 g (SD 160.0) in pregnancies with fathers aged 50 years or older (P < 0.001). The mean offspring birthweight in pregnancies with fathers aged 20-24 year old was 3465.0 g (SD 583.8), and it was 3498.9 g (SD 621.8) when the father was 50 years or older (P < 0.001). The placental to birthweight ratio in the corresponding paternal age groups were 0.191 (SD 0.039) and 0.196 (SD 0.044) (P < 0.001). In multivariable linear regression analysis the placentas in pregnancies fathered by a man of 50 years or older were estimated to weigh 13.99 g [95% confidence interval (CI) 10.88-17.10] more than in pregnancies with a 20-24-year-old father (P < 0.001) after adjustment for maternal age, birthweight, parity, offspring sex, gestational age at birth, maternal smoking, pre-eclampsia, maternal diabetes mellitus and pregnancy after ART. LIMITATIONS, REASONS FOR CAUTION:Paternal age explains only a small proportion of the total variation in placental weight. WIDER IMPLICATIONS OF THE FINDINGS:Our findings may increase the understanding of the father's role in human pregnancy. STUDY FUNDING/ COMPETING INTEREST(S):Norwegian Resource Centre for Women's Health, Norway. No conflict of interest. TRIAL REGISTRATION NUMBER:N/A.
Paternal obesity in a rodent model affects placental gene expression in a sex-specific manner.
Binder Natalie K,Beard Sally A,Kaitu'u-Lino Tu'uhevaha J,Tong Stephen,Hannan Natalie J,Gardner David K
Reproduction (Cambridge, England)
Fetal growth restriction (FGR) is a major obstetric complication stemming from poor placental development. We have previously demonstrated that paternal obesity in mice is associated with impaired embryo development and significantly reduced fetal and placental weights. We hypothesised that the FGR observed in our rodent model of paternal diet-induced obesity is associated with alterations in metabolic, cell signalling and stress pathways. Male C57BL/6 mice were fed either a normal or high-fat diet for 10 weeks before sperm collection for IVF and subsequent embryo transfer. On embryonic day 14, placentas were collected and RNA extracted from both male and female placentas to assess mRNA expression of 24 target genes using custom RT-qPCR arrays. Peroxisome proliferator-activated receptor alpha (Ppara) and caspase-12 (Casp12) expression were significantly altered in male placentas from obese fathers compared with normal (P<0.05), but not female placentas. PPARA and CASP12 proteins were localised within the placenta to trophoblast giant cells by immunohistochemistry, and relative protein abundance was determined by western blot analysis. DNA was also extracted from the same placentas to determine methylation status. Global DNA methylation was significantly increased in female placentas from obese fathers compared with normal (P<0.05), but not male placentas. In this study, we demonstrate for the first time that paternal obesity is associated with changes in gene expression and methylation status of extraembryonic tissue in a sex-specific manner. These findings reinforce the negative consequences of paternal obesity before conception, and emphasise the need for more lifestyle advice for prospective fathers.
Advanced paternal age directly impacts mouse embryonic placental imprinting.
Denomme Michelle M,Parks Jason C,McCallie Blair R,McCubbin Nathan I,Schoolcraft William B,Katz-Jaffe Mandy G
The placental epigenome plays a critical role in regulating mammalian growth and development. Alterations to placental methylation, often observed at imprinted genes, can lead to adverse pregnancy complications such as intrauterine growth restriction and preterm birth. Similar associations have been observed in offspring derived from advanced paternal age fathers. As parental age at time of conception continues to rise, the impact of advanced paternal age on these reproductive outcomes is a growing concern, but limited information is available on the molecular mechanisms affected in utero. This longitudinal murine research study thus investigated the impact of paternal aging on genomic imprinting in viable F1 embryonic portions of the placentas derived from the same paternal males when they were young (4-6 months) and when they aged (11-15 months). The use of a controlled outbred mouse model enabled analysis of offspring throughout the natural lifetime of the same paternal males and excluded confounding factors like female age or infertility. Firstly, paternal age significantly impacted embryonic placental weight, fetal weight and length. Targeted bisulfite sequencing was utilized to examine imprinted methylation at the Kcnq1ot1 imprinting control region, with significant hypermethylation observed upon natural paternal aging. Quantitative real-time PCR assessed imprinted gene expression levels at various imprinting clusters, resulting in transcript level alterations attributable to advanced paternal age. In summary, our results demonstrate a paternal age effect with dysregulation at numerous imprinted loci, providing a mechanism for future adverse placental and offspring health conditions.
Environmental exposures and development.
Mattison Donald R
Current opinion in pediatrics
PURPOSE OF REVIEW:Summarize recent studies exploring the relationship between paternal and maternal environmental exposures to chemicals before, at the time of and after conception to adverse developmental outcomes including preterm birth, death, structural and functional abnormalities and growth restriction. RECENT FINDINGS:Recent studies have demonstrated that human pregnancy and development are vulnerable to environmental exposures of the father and mother to chemical, biological and physical agents. Exposures associated with adverse developmental outcomes include air and water pollution, chemicals in foods, occupational exposures, agricultural chemicals, metals, persistent and volatile organics. Developmental endpoints which are linked with these exposures include growth restriction, functional abnormalities, structural abnormalities, preterm delivery and death. Despite this general understanding we still have incomplete knowledge concerning most exposures and the biological interactions responsible for impaired development and preterm delivery. SUMMARY:Whereas single genes and individual chemical exposures are responsible for some instances of adverse pregnancy outcome or developmental disease, gene-environment interactions are responsible for the majority. These gene-environment interactions may occur in the father, mother, placenta or fetus, suggesting that critical attention be given to maternal and paternal exposures and gene expression as they relate to the mode of action of the putative developmental toxicant both prior to and during pregnancy.
The role and interaction of imprinted genes in human fetal growth.
Moore Gudrun E,Ishida Miho,Demetriou Charalambos,Al-Olabi Lara,Leon Lydia J,Thomas Anna C,Abu-Amero Sayeda,Frost Jennifer M,Stafford Jaime L,Chaoqun Yao,Duncan Andrew J,Baigel Rachel,Brimioulle Marina,Iglesias-Platas Isabel,Apostolidou Sophia,Aggarwal Reena,Whittaker John C,Syngelaki Argyro,Nicolaides Kypros H,Regan Lesley,Monk David,Stanier Philip
Philosophical transactions of the Royal Society of London. Series B, Biological sciences
Identifying the genetic input for fetal growth will help to understand common, serious complications of pregnancy such as fetal growth restriction. Genomic imprinting is an epigenetic process that silences one parental allele, resulting in monoallelic expression. Imprinted genes are important in mammalian fetal growth and development. Evidence has emerged showing that genes that are paternally expressed promote fetal growth, whereas maternally expressed genes suppress growth. We have assessed whether the expression levels of key imprinted genes correlate with fetal growth parameters during pregnancy, either early in gestation, using chorionic villus samples (CVS), or in term placenta. We have found that the expression of paternally expressing insulin-like growth factor 2 (IGF2), its receptor IGF2R, and the IGF2/IGF1R ratio in CVS tissues significantly correlate with crown-rump length and birthweight, whereas term placenta expression shows no correlation. For the maternally expressing pleckstrin homology-like domain family A, member 2 (PHLDA2), there is no correlation early in pregnancy in CVS but a highly significant negative relationship in term placenta. Analysis of the control of imprinted expression of PHLDA2 gave rise to a maternally and compounded grand-maternally controlled genetic effect with a birthweight increase of 93/155 g, respectively, when one copy of the PHLDA2 promoter variant is inherited. Expression of the growth factor receptor-bound protein 10 (GRB10) in term placenta is significantly negatively correlated with head circumference. Analysis of the paternally expressing delta-like 1 homologue (DLK1) shows that the paternal transmission of type 1 diabetes protective G allele of rs941576 single nucleotide polymorphism (SNP) results in significantly reduced birth weight (-132 g). In conclusion, we have found that the expression of key imprinted genes show a strong correlation with fetal growth and that for both genetic and genomics data analyses, it is important not to overlook parent-of-origin effects.
Preliminary evidence of a paternal-maternal genetic conflict on the placenta: Link between imprinting disorder and multi-generational hypertensive disorders.
Naruse Katsuhiko,Tsunemi Taihei,Kawahara Naoki,Kobayashi Hiroshi
There has been great research progress on hypertensive disorders in pregnancy (HDP) in the last few decades. Failure of placentation, especially a lack of uterine spiral artery remodeling, is the main pathological finding of HDP. Currently, members of the vascular endothelial growth factor family are used as markers for the early prediction of onset of HDP. Epidemiologic research has also shown that HDP can have effects on the next generation infants, representing a Development Origins of Health and Disease-related disease. However, the precise pathogenic mechanism and the effect of HDP on the offspring remain unclear. The group of strong pro-inflammatory molecules known as "danger signals" have been shown to be released from the placental trophoblast surface and increase in the maternal circulation in HDP, which are then possibly transported into the fetal circulation. These signals, including fatty acids or adipocytokines, may alter the offspring's health in later life. Moreover, a hypoxic condition alters placental methylation, and the change may be passed onto the fetus. Although the genetic origin of the disease is still unknown, a hypothesis has been put forward that a paternal-maternal genetic conflict, mainly at imprinting lesion sites, may be a key factor for disease initiation. In particular, an imbalance in paternal and maternal factors may impede proper placentation, trophoblast invasion, decidualization or immune moderation so as to achieve better nutrition for the fetus (paternal) versus ensuring safe delivery and further pregnancy (maternal). Here, we review this research progress on HDP and focus on this novel genetic conflict concept, which is expected to provide new insight into the cause, pathophysiology, and multi-generational effects of HDP.