Cleavage factor 25 deregulation contributes to pulmonary fibrosis through alternative polyadenylation.
Weng Tingting,Ko Junsuk,Masamha Chioniso P,Xia Zheng,Xiang Yu,Chen Ning-Yuan,Molina Jose G,Collum Scott,Mertens Tinne C,Luo Fayong,Philip Kemly,Davies Jonathan,Huang Jingjing,Wilson Cory,Thandavarayan Rajarajan A,Bruckner Brian A,Jyothula Soma Sk,Volcik Kelly A,Li Lei,Han Leng,Li Wei,Assassi Shervin,Karmouty-Quintana Harry,Wagner Eric J,Blackburn Michael R
The Journal of clinical investigation
Idiopathic pulmonary fibrosis (IPF) is a chronic and deadly disease with a poor prognosis and few treatment options. Pathological remodeling of the extracellular matrix (ECM) by myofibroblasts is a key factor that drives disease pathogenesis, although the underlying mechanisms remain unknown. Alternative polyadenylation (APA) has recently been shown to play a major role in cellular responses to stress by driving the expression of fibrotic factors and ECMs through altering microRNA sensitivity, but a connection to IPF has not been established. Here, we demonstrate that CFIm25, a global regulator of APA, is down-regulated in the lungs of patients with IPF and mice with pulmonary fibrosis, with its expression selectively reduced in alpha-smooth muscle actin (α-SMA) positive fibroblasts. Following the knockdown of CFIm25 in normal human lung fibroblasts, we identified 808 genes with shortened 3'UTRs, including those involved in the transforming growth factor-β signaling pathway, the Wnt signaling pathway, and cancer pathways. The expression of key pro-fibrotic factors can be suppressed by CFIm25 overexpression in IPF fibroblasts. Finally, we demonstrate that deletion of CFIm25 in fibroblasts or myofibroblast precursors using either the Col1a1 or the Foxd1 promoter enhances pulmonary fibrosis after bleomycin exposure in mice. Taken together, our results identified CFIm25 down-regulation as a novel mechanism to elevate pro-fibrotic gene expression in pulmonary fibrosis.
BOS Is Associated With Decreased SIRT1 in Peripheral Blood Proinflammatory T, NK, and NKT-like Lymphocytes.
Hodge Greg,Hodge Sandra,Liu Hong,Nguyen Phan,Holmes-Liew Chien-Li,Holmes Mark
BACKGROUND:Immunosuppression therapy is ineffective at preventing chronic rejection of lung allografts (bronchiolitis obliterans syndrome [BOS]) and proinflammatory cytokines by steroid-resistant lymphocytes. The class III NAD-sirtuin 1 (SIRT1) is an important negative regulator of inflammation; however, SIRT1 activity following lung transplant has not been studied. We hypothesized that SIRT1 expression is decreased in proinflammatory lymphocytes following lung transplant and that treatment with SIRT1 activators (resveratrol, curcumin) and agents that prevent NAD depletion (theophylline) upregulate SIRT1 and reduce proinflammatory cytokine expression in these cells. METHODS:Intracellular proinflammatory cytokines and SIRT1 were measured in blood T, natural killer T-like cell (NKT-like), and natural killer (NK) cells from patients with BOS (n = 10), stable lung transplant patients (n = 11), and healthy aged-matched controls (n = 10). Blood was cultured in the presence of ±25 µM resveratrol, ±1 µM curcumin, ±5 mg/L theophylline, ±1µM prednisolone and cytokines, and SIRT1 assessed using flow cytometry. RESULTS:There was a loss of SIRT1 in T, NK-like, and NK cells in BOS patients compared with stable patients and controls (%CD8 SIRT1 T cells: 17 ± 10; 37 ± 10; 30 ± 10) (mean ± SEM BOS, stable, control, respectively) (P < 0.05 for all). Loss of SIRT1 was associated with increased T, NKT-like, and NK cells expressing interferon (IFN)γ and tumor necrosis factor (TNF)α. SIRT1 expression by T cells significantly associated with FEV1 (R = 0.655, P = 0.006) and with time posttransplant (R = -0.552, P = 0.041). All treatments upregulated SIRT1 and inhibited IFNγ and TNFα production by T, NK, and NKT-like cells additively. CONCLUSIONS:BOS is associated with decreased SIRT1 in peripheral blood proinflammatory T, NK, and NKT-like lymphocytes following lung transplant. Treatment options that increase SIRT1 may improve graft survival.
Reduction in podocyte SIRT1 accelerates kidney injury in aging mice.
Chuang Peter Y,Cai Weijing,Li Xuezhu,Fang Lu,Xu Jin,Yacoub Rabi,He John Cijiang,Lee Kyung
American journal of physiology. Renal physiology
Both the incidence and prevalence of chronic kidney disease are increasing in the elderly population. Although aging is known to induce kidney injury, the underlying molecular mechanisms remain unclear. Sirtuin 1 (Sirt1), a longevity gene, is known to protect kidney cell injury from various cellular stresses. In previous studies, we showed that the podocyte-specific loss of Sirt1 aggravates diabetic kidney injury. However, the role of Sirt1 in aging-induced podocyte injury is not known. Therefore, in this study we sought to determine the effects of podocyte-specific reduction of Sirt1 in age-induced kidney injury. We employed the inducible podocyte-specific Sirt1 knockdown mice that express shRNA against Sirt1 (Pod-Sirt1) and control mice that express shRNA for luciferase (Pod-Luci). We found that reduction of podocyte Sirt1 led to aggravated aging-induced glomerulosclerosis and albuminuria. In addition, urinary level of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative stress, was markedly increased in aged Pod-Sirt1 mice compared with aged Pod-Luci mice. Although podocyte-specific markers decreased in aged mice compared with the young controls, the decrease was further exacerbated in aged Pod-Sirt1 compared with Pod-Luci mice. Interestingly, expression of cellular senescence markers was significantly higher in the glomeruli of Pod-Sirt1 mice than Pod-Luci mice, suggesting that cellular senescence may contribute to podocyte loss in aging kidneys. Finally, we confirmed that Pod-Sirt1 glomeruli were associated with reduced activation of the transcription factors peroxisome proliferator-activated receptor (PPAR)-α coactivador-1 (PGC1α)/PPARγ, forkhead box O (FOXO)3, FOXO4, and p65 NF-κB, through SIRT1-mediated deacetylation. Together, our data suggest that SIRT1 may be a potential therapeutic target to treat patients with aging-related kidney disease.
Increased podocyte Sirtuin-1 function attenuates diabetic kidney injury.
Hong Quan,Zhang Lu,Das Bhaskar,Li Zhengzhe,Liu Bohan,Cai Guangyan,Chen Xiangmei,Chuang Peter Y,He John Cijiang,Lee Kyung
Podocyte injury and loss contribute to the progression of glomerular diseases, including diabetic kidney disease. We previously found that the glomerular expression of Sirtuin-1 (SIRT1) is reduced in human diabetic glomeruli and that the podocyte-specific loss of SIRT1 aggravated albuminuria and worsened kidney disease progression in diabetic mice. SIRT1 encodes an NAD-dependent deacetylase that modifies the activity of key transcriptional regulators affected in diabetic kidneys, including NF-κB, STAT3, p53, FOXO4, and PGC1-α. However, whether the increased glomerular SIRT1 activity is sufficient to ameliorate the pathogenesis of diabetic kidney disease has not been explored. We addressed this by inducible podocyte-specific SIRT1 overexpression in diabetic OVE26 mice. The induction of SIRT1 overexpression in podocytes for six weeks in OVE26 mice with established albuminuria attenuated the progression of diabetic glomerulopathy. To further validate the therapeutic potential of increased SIRT1 activity against diabetic kidney disease, we developed a new, potent and selective SIRT1 agonist, BF175. In cultured podocytes BF175 increased SIRT1-mediated activation of PGC1-α and protected against high glucose-mediated mitochondrial injury. In vivo, administration of BF175 for six weeks in OVE26 mice resulted in a marked reduction in albuminuria and in glomerular injury in a manner similar to podocyte-specific SIRT1 overexpression. Both podocyte-specific SIRT1 overexpression and BT175 treatment attenuated diabetes-induced podocyte loss and reduced oxidative stress in glomeruli of OVE26 mice. Thus, increased SIRT1 activity protects against diabetes-induced podocyte injury and effectively mitigates the progression of diabetic kidney disease.
SIRT1 and HIF1α signaling in metabolism and immune responses.
Yu Qing,Dong Lin,Li Yan,Liu Gaungwei
SIRT1 and HIF1α are regarded as two key metabolic sensors in cellular metabolism pathways and play vital roles in influencing immune responses. SIRT1 and HIF1α regulate immune responses in metabolism-dependent and -independent ways. Here, we summarized the recent knowledge of SIRT1 and HIF1α signaling in metabolism and immune responses. HIF1α is a direct target of SIRT1. Sometimes, SIRT1 and HIF1α cooperate or act separately to mediate immune responses. In innate immune responses, SIRT1 can regulate the glycolytic activity of myeloid-derived suppressor cells (MDSCs) and influence MDSC functional differentiation. SIRT1 can regulate monocyte function through NF-κB and PGC-1, accompanying an increased NAD level. The SIRT1-HIF1α axis bridges the innate immune signal to an adaptive immune response by directing cytokine production of dendritic cells in a metabolism-independent manner, promoting the differentiation of CD4 T cells. For adaptive immune cells, SIRT1 can mediate the differentiation of inflammatory T cell subsets in a NAD-dependent manner. HIF1α can stimulate some glycolysis-associated genes and regulate the ATP and ROS generations. In addition, SIRT1-and HIF1α-associated metabolism inhibits the activity of mTOR, thus negatively regulating the differentiation and function of Th9 cells. As immune cells are crucial in controlling immune-associated diseases, SIRT1-and HIF1α associated-metabolism is closely linked to immune-associated diseases, including infection, tumors, allergic airway inflammation, and autoimmune diseases.
Sirtuin-1 in immunotherapy: A Janus-headed target.
Chadha Sakshum,Wang Liqing,Hancock Wayne W,Beier Ulf H
Journal of leukocyte biology
Sirtuin-1 (Sirt1), a member of the NAD-dependent sirtuin family of histone/protein deacetylases (HDAC), is an important target for immunotherapy due to its role in deacetylating the transcription factors Foxp3 and thymic retinoid acid receptor related orphan receptor gamma (RORγt). Sirt1 inhibition can increase Foxp3 acetylation and promote the production and functions of Foxp3 T-regulatory (Treg) cells, whereas the acetylation of RORγt decreases its transcriptional activity DNA binding and decreases the differentiation of proinflammatory Th17 cells. Pharmacologic inhibitors of Sirt1 increase allograft survival and decrease autoimmune colitis and experimental allergic encephalomyelitis. However, in contrast to its role in T cells, Sirt1 has anti-inflammatory effects in myeloid cells, and, context dependent, in Th17 cells. Here, inhibition of Sirt1 can have proinflammatory effects. In addition to effects arising from the central role of Sirt1 in cellular metabolism and NAD-dependent reactions, such proinflammatory effects further complicate the potential of Sirt1 for therapeutic immunosuppression. This review aims to reconcile the opposing literature on pro- and anti-inflammatory effects of Sirt1, provides an overview of the role of Sir1 in the immune system, and discusses the pros and cons associated with inhibiting Sirt1 for control of inflammation and immune responses.
MicroRNA MiR-17 retards tissue growth and represses fibronectin expression.
Shan Sze Wan,Lee Daniel Y,Deng Zhaoqun,Shatseva Tatiana,Jeyapalan Zina,Du William W,Zhang Yaou,Xuan Jim W,Yee Siu-Pok,Siragam Vinayakumar,Yang Burton B
Nature cell biology
MicroRNAs (miRNAs) are single-stranded regulatory RNAs, frequently expressed as clusters. Previous studies have demonstrated that the six-miRNA cluster miR-17~92 has important roles in tissue development and cancers. However, the precise role of each miRNA in the cluster is unknown. Here we show that overexpression of miR-17 results in decreased cell adhesion, migration and proliferation. Transgenic mice overexpressing miR-17 showed overall growth retardation, smaller organs and greatly reduced haematopoietic cell lineages. We found that fibronectin and the fibronectin type-III domain containing 3A (FNDC3A) are two targets that have their expression repressed by miR-17, both in vitro and in transgenic mice. Several lines of evidence support the notion that miR-17 causes cellular defects through its repression of fibronectin expression. Our single miRNA expression assay may be evolved to allow the manipulation of individual miRNA functions in vitro and in vivo. We anticipate that this could serve as a model for studying gene regulation by miRNAs in the development of gene therapy.
Starvation and diabetes reduce the amount of pyruvate dehydrogenase phosphatase in rat heart and kidney.
Huang Boli,Wu Pengfei,Popov Kirill M,Harris Robert A
The pyruvate dehydrogenase complex (PDC) is inactivated in many tissues during starvation and diabetes to conserve three-carbon compounds for gluconeogenesis. This is achieved by an increase in the extent of PDC phosphorylation caused in part by increased pyruvate dehydrogenase kinase (PDK) activity due to increased PDK expression. This study examined whether altered pyruvate dehydrogenase phosphatase (PDP) expression also contributes to changes in the phosphorylation state of PDC during starvation and diabetes. Of the two PDP isoforms expressed in mammalian tissues, the Ca(2+)-sensitive isoform (PDP1) is highly expressed in rat heart, brain, and testis and is detectable but less abundant in rat muscle, lung, kidney, liver, and spleen. The Ca(2+)-insensitive isoform (PDP2) is abundant in rat kidney, liver, heart, and brain and is detectable in spleen and lung. Starvation and streptozotocin-induced diabetes cause decreases in PDP2 mRNA abundance, PDP2 protein amount, and PDP activity in rat heart and kidney. Refeeding and insulin treatment effectively reversed these effects of starvation and diabetes, respectively. These findings indicate that opposite changes in expression of specific PDK and PDP isoenzymes contribute to hyperphosphorylation and therefore inactivation of the PDC in heart and kidney during starvation and diabetes.
Structural analysis of human 2'-O-ribose methyltransferases involved in mRNA cap structure formation.
Smietanski Miroslaw,Werner Maria,Purta Elzbieta,Kaminska Katarzyna H,Stepinski Janusz,Darzynkiewicz Edward,Nowotny Marcin,Bujnicki Janusz M
The 5' cap of human messenger RNA contains 2'-O-methylation of the first and often second transcribed nucleotide that is important for its processing, translation and stability. Human enzymes that methylate these nucleotides, termed CMTr1 and CMTr2, respectively, have recently been identified. However, the structures of these enzymes and their mechanisms of action remain unknown. In the present study, we solve the crystal structures of the active CMTr1 catalytic domain in complex with a methyl group donor and a capped oligoribonucleotide, thereby revealing the mechanism of specific recognition of capped RNA. This mechanism differs significantly from viral enzymes, thus providing a framework for their specific targeting. Based on the crystal structure of CMTr1, a comparative model of the CMTr2 catalytic domain is generated. This model, together with mutational analysis, leads to the identification of residues involved in RNA and methyl group donor binding.
Transforming growth factor β1 alters the 3'-UTR of mRNA to promote lung fibrosis.
Ko Junsuk,Mills Tingting,Huang Jingjing,Chen Ning-Yuan,Mertens Tinne C J,Collum Scott D,Lee Garam,Xiang Yu,Han Leng,Zhou Yang,Lee Chun Geun,Elias Jack A,Jyothula Soma S K,Rajagopal Keshava,Karmouty-Quintana Harry,Blackburn Michael R
The Journal of biological chemistry
Idiopathic pulmonary fibrosis (IPF) is a chronic disease characterized by the pathological remodeling of air sacs as a result of excessive accumulation of extracellular matrix (ECM) proteins, but the mechanism governing the robust protein expression is poorly understood. Our recent findings demonstrate that alternative polyadenylation (APA) caused by NUDT21 reduction is important for the increased expression of fibrotic mediators and ECM proteins in lung fibroblasts by shortening the 3'-untranslated regions (3'-UTRs) of mRNAs and stabilizing their transcripts, therefore activating pathological signaling pathways. Despite the importance of NUDT21 reduction in the regulation of fibrosis, the underlying mechanisms for the depletion are unknown. We demonstrate here that NUDT21 is depleted by TGFβ1. We found that miR203, which is increased in IPF, was induced by TGFβ1 to target the NUDT21 3'-UTR, thus depleting NUDT21 in human and mouse lung fibroblasts. TGFβ1-mediated NUDT21 reduction was attenuated by the miR203 inhibitor antagomiR203 in fibroblasts. TGFβ1 transgenic mice revealed that TGFβ1 down-regulates NUDT21 in fibroblasts Furthermore, TGFβ1 promoted differential APA of fibrotic genes, including FGF14, RICTOR, TMOD2, and UCP5, in association with increased protein expression. This unique differential APA signature was also observed in IPF fibroblasts. Altogether, our results identified TGFβ1 as an APA regulator through NUDT21 depletion amplifying pulmonary fibrosis.
Silencing NUDT21 Attenuates the Mesenchymal Identity of Glioblastoma Cells via the NF-κB Pathway.
Lou Jia-Cheng,Lan Yu-Long,Gao Jin-Xia,Ma Bin-Bin,Yang Ting,Yuan Zhong-Bo,Zhang Hong-Qiang,Zhu Ting-Zhun,Pan Ning,Leng Song,Song Gui-Jun,Zhang Bo
Frontiers in molecular neuroscience
The proneural (PN) and mesenchymal (MES) subtypes of glioblastoma multiforme (GBM) are robust and generally consistent with classification schemes. GBMs in the MES subclass are predominantly primary tumors that, compared to PN tumors, exhibit a worse prognosis; thus, understanding the mechanism of MES differentiation may be of great benefit for the treatment of GBM. Nuclear factor kappa B (NF-κB) signaling is critically important in GBM, and activation of NF-κB could induce MES transdifferentiation in GBM, which warrants additional research. is a newly discovered tumor-associated gene according to our current research. The exact roles of in cancer incidence have not been elucidated. Here, we report that expression was upregulated in human glioma tissues and that promoted glioma cell proliferation, likely through the NF-κB signaling pathway. Gene set enrichment analysis, western blotting, and quantitative real-time reverse transcription polymerase chain reaction confirmed that NF-κB inhibitor zeta (NFKBIZ) was a downstream target affected by and that the MES identity genes in glioblastoma cells, and , were also differentially regulated. Our results suggest that is an upstream regulator of the NF-κB pathway and a potential molecular target for the MES subtype of GBM.
NUDT21 inhibits bladder cancer progression through ANXA2 and LIMK2 by alternative polyadenylation.
Xiong Ming,Chen Liang,Zhou Lijie,Ding Yong,Kazobinka Gallina,Chen Zhaohui,Hou Teng
Nudix Hydrolase 21 (NUDT21) is a crucial mediator involved in alternative polyadenylation (APA), and this molecule has been reported to be a tumor suppressor in human cancers. However, neither the role NUDT21 plays in bladder cancer (BC) nor the mechanisms which are involved have been investigated. Expression levels of NUDT21 in BC were evaluated with real-time PCR, western blotting, and immunohistochemistry (IHC). and assays were performed to investigate the function of NUDT21 in tumorigenesis in bladder cancer cells. The TOP/FOP flash reporter assay, western blot, and global APA site profiling analysis were used to identify the pathway which mediates the biologic roles of NUDT21 in BC. NUDT21 expression is reduced in BC tissue and cells, and BC patients with lower NUDT21 expression have shorter overall and recurrent-free survival than patients with higher NUDT21 expression. NUDT21 ectopic expression or knockdown respectively profoundly inhibited or promoted the capacity of BC cells for proliferation, migration and invasion. We also identified a number of genes with shortened 3'UTRs through modulation of NUDT21 expression, and further characterized the NUDT21-regulated genes ANXA2 and LIMK2. We found NUDT21 modulates the expression of ANXA2 and LIMK2 in the Wnt/β-catenin and NF-κB signaling pathways. These findings show NUDT21 plays a crucial role in BC progression, at least in part through ANXA2 and LIMK2 which act by alternative polyadenylation. NUDT21 may thus have potential as a diagnostic and therapeutic target in treatment of BC.