Follicle-Stimulating Hormone Exacerbates Cardiovascular Disease in the Presence of Low or Castrate Testosterone Levels.
JACC. Basic to translational science
Low testosterone (T), common in aging men, associates with cardiovascular disease. We investigated whether follicle-stimulating hormone (FSH), which is affected by T, modulates the cardiovascular effects associated with low T or castration. FSHβ:low-density lipoprotein receptor (LDLR) mice, untreated or castrated (orchiectomy, gonadotropin-releasing hormone agonist or antagonist), demonstrated significantly less atherogenesis compared with similarly treated LDLR mice, but not following FSH delivery. Smaller plaque burden in LDLR mice receiving gonadotropin-releasing hormone antagonists vs agonists were nullified in FSHβ:LDLR mice. Atherosclerotic and necrotic plaque size and macrophage infiltration correlated with serum FSH/T. In patients with prostate cancer, FSH/T following androgen-deprivation therapy initiation predicted cardiovascular events. FSH facilitates cardiovascular disease when T is low or eliminated.
10.1016/j.jacbts.2023.10.010
Deficiency of ASGR1 in pigs recapitulates reduced risk factor for cardiovascular disease in humans.
Xie Baocai,Shi Xiaochen,Li Yan,Xia Bo,Zhou Jia,Du Minjie,Xing Xiangyang,Bai Liang,Liu Enqi,Alvarez Fernando,Jin Long,Deng Shaoping,Mitchell Grant A,Pan Dengke,Li Mingzhou,Wu Jiangwei
PLoS genetics
Genetic variants in the asialoglycoprotein receptor 1 (ASGR1) are associated with a reduced risk of cardiovascular disease (CVD) in humans. However, the underlying molecular mechanism remains elusive. Given the cardiovascular similarities between pigs and humans, we generated ASGR1-deficient pigs using the CRISPR/Cas9 system. These pigs show age-dependent low levels of non-HDL-C under standard diet. When received an atherogenic diet for 6 months, ASGR1-deficient pigs show lower levels of non-HDL-C and less atherosclerotic lesions than that of controls. Furthermore, by analysis of hepatic transcriptome and in vivo cholesterol metabolism, we show that ASGR1 deficiency reduces hepatic de novo cholesterol synthesis by downregulating 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), and increases cholesterol clearance by upregulating the hepatic low-density lipoprotein receptor (LDLR), which together contribute to the low levels of non-HDL-C. Despite the cardioprotective effect, we unexpectedly observed mild to moderate hepatic injury in ASGR1-deficient pigs, which has not been documented in humans with ASGR1 variants. Thus, targeting ASGR1 might be an effective strategy to reduce hypercholesterolemia and atherosclerosis, whereas further clinical evidence is required to assess its hepatic impact.
10.1371/journal.pgen.1009891
N-Glycosylation Defects in Humans Lower Low-Density Lipoprotein Cholesterol Through Increased Low-Density Lipoprotein Receptor Expression.
van den Boogert Marjolein A W,Larsen Lars E,Ali Lubna,Kuil Sacha D,Chong Patrick L W,Loregger Anke,Kroon Jeffrey,Schnitzler Johan G,Schimmel Alinda W M,Peter Jorge,Levels Johannes H M,Steenbergen Gerry,Morava Eva,Dallinga-Thie Geesje M,Wevers Ron A,Kuivenhoven Jan Albert,Hand Nicholas J,Zelcer Noam,Rader Daniel J,Stroes Erik S G,Lefeber Dirk J,Holleboom Adriaan G
Circulation
BACKGROUND:The importance of protein glycosylation in regulating lipid metabolism is becoming increasingly apparent. We set out to further investigate this by studying patients with type I congenital disorders of glycosylation (CDGs) with defective N-glycosylation. METHODS:We studied 29 patients with the 2 most prevalent types of type I CDG, ALG6 (asparagine-linked glycosylation protein 6)-deficiency CDG and PMM2 (phosphomannomutase 2)-deficiency CDG, and 23 first- and second-degree relatives with a heterozygous mutation and measured plasma cholesterol levels. Low-density lipoprotein (LDL) metabolism was studied in 3 cell models-gene silencing in HepG2 cells, patient fibroblasts, and patient hepatocyte-like cells derived from induced pluripotent stem cells-by measuring apolipoprotein B production and secretion, LDL receptor expression and membrane abundance, and LDL particle uptake. Furthermore, SREBP2 (sterol regulatory element-binding protein 2) protein expression and activation and endoplasmic reticulum stress markers were studied. RESULTS:We report hypobetalipoproteinemia (LDL cholesterol [LDL-C] and apolipoprotein B below the fifth percentile) in a large cohort of patients with type I CDG (mean age, 9 years), together with reduced LDL-C and apolipoprotein B in clinically unaffected heterozygous relatives (mean age, 46 years), compared with 2 separate sets of age- and sex-matched control subjects. ALG6 and PMM2 deficiency led to markedly increased LDL uptake as a result of increased cell surface LDL receptor abundance. Mechanistically, this outcome was driven by increased SREBP2 protein expression accompanied by amplified target gene expression, resulting in higher LDL receptor protein levels. Endoplasmic reticulum stress was not found to be a major mediator. CONCLUSIONS:Our study establishes N-glycosylation as an important regulator of LDL metabolism. Given that LDL-C was also reduced in a group of clinically unaffected heterozygotes, we propose that increasing LDL receptor-mediated cholesterol clearance by targeting N-glycosylation in the LDL pathway may represent a novel therapeutic strategy to reduce LDL-C and cardiovascular disease.
10.1161/CIRCULATIONAHA.118.036484
A common variant in CCDC93 protects against myocardial infarction and cardiovascular mortality by regulating endosomal trafficking of low-density lipoprotein receptor.
European heart journal
AIMS:Genome-wide association studies have previously identified INSIG2 as a candidate gene for plasma low-density lipoprotein cholesterol (LDL-c). However, we suspect a role for CCDC93 in the same locus because of its involvement in the recycling of the LDL-receptor (LDLR). METHODS AND RESULTS:Characterization of the INSIG2 locus was followed by studies in over 107 000 individuals from the general population, the Copenhagen General Population Study and the Copenhagen City Heart Study, for associations of genetic variants with plasma lipids levels, with risk of myocardial infarction (MI) and with cardiovascular mortality. CCDC93 was furthermore studied in cells and mice. The lead variant of the INSIG2 locus (rs10490626) is not associated with changes in the expression of nearby genes but is a part of a genetic block, which excludes INSIG2. This block includes a coding variant in CCDC93 p.Pro228Leu, which is in strong linkage disequilibrium with rs10490626 (r2 > 0.96). In the general population, separately and combined, CCDC93 p.Pro228Leu is dose-dependently associated with lower LDL-c (P-trend 2.5 × 10-6 to 8.0 × 10-9), with lower risk of MI (P-trend 0.04-0.002) and lower risk of cardiovascular mortality (P-trend 0.005-0.004). These results were validated for LDL-c, risk of both coronary artery disease and MI in meta-analyses including from 194 000 to >700 000 participants. The variant is shown to increase CCDC93 protein stability, while overexpression of human CCDC93 decreases plasma LDL-c in mice. Conversely, CCDC93 ablation reduces LDL uptake as a result of reduced LDLR levels at the cell membrane. CONCLUSION:This study provides evidence that a common variant in CCDC93, encoding a protein involved in recycling of the LDLR, is associated with lower LDL-c levels, lower risk of MI and cardiovascular mortality.
10.1093/eurheartj/ehz727
SUMOylation of the ubiquitin ligase IDOL decreases LDL receptor levels and is reversed by SENP1.
Wang Ju-Qiong,Lin Zi-Cun,Li Liang-Liang,Zhang Shao-Fang,Li Wei-Hui,Liu Wei,Song Bao-Liang,Luo Jie
The Journal of biological chemistry
Inducible degrader of the low-density lipoprotein receptor (IDOL) is an E3 ubiquitin ligase mediating degradation of low-density lipoprotein (LDL) receptor (LDLR). IDOL also controls its own stability through autoubiquitination, primarily at lysine 293. Whether IDOL may undergo other forms of posttranslational modification is unknown. In this study, we show that IDOL can be modified by small ubiquitin-like modifier 1 at the K293 residue at least. The SUMOylation of IDOL counteracts its ubiquitination and augments IDOL protein levels. SUMOylation and the associated increase of IDOL protein are effectively reversed by SUMO-specific peptidase 1 (SENP1) in an activity-dependent manner. We further demonstrate that SENP1 affects LDLR protein levels by modulating IDOL. Overexpression of SENP1 increases LDLR protein levels and enhances LDL uptake in cultured cells. On the contrary, loss of SENP1 lowers LDLR levels in an IDOL-dependent manner and reduces LDL endocytosis. Collectively, our results reveal SUMOylation as a new regulatory posttranslational modification of IDOL and suggest that SENP1 positively regulates the LDLR pathway via deSUMOylation of IDOL and may therefore be exploited for the treatment of cardiovascular disease.
10.1074/jbc.RA120.015420
Posttranscriptional Regulation of the Human LDL Receptor by the U2-Spliceosome.
Zanoni Paolo,Panteloglou Grigorios,Othman Alaa,Haas Joel T,Meier Roger,Rimbert Antoine,Futema Marta,Abou Khalil Yara,Norrelykke Simon F,Rzepiela Andrzej J,Stoma Szymon,Stebler Michael,van Dijk Freerk,Wijers Melinde,Wolters Justina C,Dalila Nawar,Huijkman Nicolette C A,Smit Marieke,Gallo Antonio,Carreau Valérie,Philippi Anne,Rabès Jean-Pierre,Boileau Catherine,Visentin Michele,Vonghia Luisa,Weyler Jonas,Francque Sven,Verrijken An,Verhaegen Ann,Van Gaal Luc,van der Graaf Adriaan,van Rosmalen Belle V,Robert Jerome,Velagapudi Srividya,Yalcinkaya Mustafa,Keel Michaela,Radosavljevic Silvija,Geier Andreas,Tybjaerg-Hansen Anne,Varret Mathilde,Rohrer Lucia,Humphries Steve E,Staels Bart,van de Sluis Bart,Kuivenhoven Jan Albert,von Eckardstein Arnold
Circulation research
BACKGROUND:The LDLR (low-density lipoprotein receptor) in the liver is the major determinant of LDL-cholesterol levels in human plasma. The discovery of genes that regulate the activity of LDLR helps to identify pathomechanisms of hypercholesterolemia and novel therapeutic targets against atherosclerotic cardiovascular disease. METHODS:We performed a genome-wide RNA interference screen for genes limiting the uptake of fluorescent LDL into Huh-7 hepatocarcinoma cells. Top hit genes were validated by in vitro experiments as well as analyses of data sets on gene expression and variants in human populations. RESULTS:The knockdown of 54 genes significantly inhibited LDL uptake. Fifteen of them encode for components or interactors of the U2-spliceosome. Knocking down any one of 11 out of 15 genes resulted in the selective retention of intron 3 of . The translated LDLR fragment lacks 88% of the full length LDLR and is detectable neither in nontransfected cells nor in human plasma. The hepatic expression of the intron 3 retention transcript is increased in nonalcoholic fatty liver disease as well as after bariatric surgery. Its expression in blood cells correlates with LDL-cholesterol and age. Single nucleotide polymorphisms and 3 rare variants of one spliceosome gene, , are associated with LDL-cholesterol in the population and familial hypercholesterolemia, respectively. Compared with overexpression of wild-type , overexpression of the 3 rare mutants in Huh-7 cells led to lower LDL uptake. CONCLUSIONS:We identified a novel mechanism of posttranscriptional regulation of LDLR activity in humans and associations of genetic variants of with LDL-cholesterol levels.
10.1161/CIRCRESAHA.120.318141
IDOL G51S Variant Is Associated With High Blood Cholesterol and Increases Low-Density Lipoprotein Receptor Degradation.
Adi Dilare,Lu Xiao-Yi,Fu Zhen-Yan,Wei Jian,Baituola Gulinaer,Meng Ya-Jie,Zhou Yu-Xia,Hu Ao,Wang Jin-Kai,Lu Xiang-Feng,Wang Yan,Song Bao-Liang,Ma Yi-Tong,Luo Jie
Arteriosclerosis, thrombosis, and vascular biology
OBJECTIVE:A high level of LDL-C (low-density lipoprotein cholesterol) is a major risk factor for cardiovascular disease. The E3 ubiquitin ligase named IDOL (inducible degrader of the LDLR [LDL receptor]; also known as MYLIP [myosin regulatory light chain interacting protein]) mediates degradation of LDLR through ubiquitinating its C-terminal tail. But the expression profile of IDOL differs greatly in the livers of mice and humans. Whether IDOL is able to regulate LDL-C levels in humans remains to be determined. Approach and Results: By using whole-exome sequencing, we identified a nonsynonymous variant rs149696224 in the gene that causes a G51S (Gly-to-Ser substitution at the amino acid site 51) from a Chinese Uygur family. Large cohort analysis revealed IDOL G51S carriers (+/G51S) displayed significantly higher LDL-C levels. Mechanistically, the G51S mutation stabilized IDOL protein by inhibiting its dimerization and preventing self-ubiquitination and subsequent proteasomal degradation. IDOL(G51S) exhibited a stronger ability to promote ubiquitination and degradation of LDLR. Adeno-associated virus-mediated expression of IDOL(G51S) in mouse liver decreased hepatic LDLR and increased serum levels of LDL-C, total cholesterol, and triglyceride. CONCLUSIONS:Our study demonstrates that IDOL(G51S) is a gain-of-function variant responsible for high LDL-C in both humans and mice. These results suggest that IDOL is a key player regulating cholesterol level in humans.
10.1161/ATVBAHA.119.312589
Diagnosis and treatment of familial hypercholesterolaemia.
Hovingh G Kees,Davidson Michael H,Kastelein John J P,O'Connor Anne M
European heart journal
Familial hypercholesterolaemia (FH) is an autosomal dominant genetic disorder, associated with elevated levels of low-density lipoprotein-cholesterol (LDL-C), which can lead to premature cardiovascular disease. Early diagnosis of FH is important to prevent morbidity and mortality. Familial hypercholesterolaemia is usually diagnosed using clinical characteristics, such as family history, and cholesterol levels; however, genetic testing may provide a definite diagnosis of FH by detecting a pathological mutation. Current guidelines highlight the importance of reducing LDL-C levels in patients with FH. Statins are the current standard treatment for the majority of these patients, and have been shown to be effective in reducing the incidence of cardiovascular heart disease in patients with FH. Nevertheless, many FH patients do not achieve their target LDL-C levels; as such, new treatment options are required to decrease LDL-C levels beyond those currently achieved. There are currently several new classes of pharmacotherapy under investigation to control LDL-C levels. These include agents which modify LDL-C production, such as inhibitors of apolipoprotein B, or those which affect LDL-C catabolism, such as inhibition of pro-protein convertase subtilisin/kexin 9, a protein which is responsible for the degradation of the LDL receptor. Therapies which raise high-density lipoprotein cholesterol are also being evaluated. In this article, we consider the diagnosis of FH and the goals of therapy and review the current and potential future treatment options for patients with FH.
10.1093/eurheartj/eht015
[Research progress on the correlation between small dense low-density lipoprotein-cholesterol and atherosclerotic cardiovascular disease].
Fan X S,Shen L L,Hu R,He J X,Li Y T,Yuan H
Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine]
Atherosclerotic cardiovascular disease (ASCVD), a series of cardiovascular diseases based on atherosclerosis, has attracted more clinical attention. However, with the increase of population-based research results, the diagnostic value of traditional blood lipid parameters such as low density lipoprotein-cholesterol (LDL-C) is showing limitations. In recent years, a large number of studies have confirmed that small dense low-density lipoprotein cholesterol (sdLDL-C) has lower affinity with low-density lipoprotein receptor, longer circulation time and easier to penetrate arterial endothelium, so it has stronger atherogenic effect. Therefore, we summarize the common detection methods of sdLDL-C, the research progress of the correlation between sdLDL-C and ASCVD risk, as well as the intervention measures and influencing factors of sdLDL-C level, in order to deepen the clinician's understanding of the role of sdLDL-C in ASCVD and achieve the early prevention, early detection and early diagnosis of chronic atherosclerosis.
10.3760/cma.j.cn112150-20210817-00801
Homozygous familial hypercholesterolemia: current perspectives on diagnosis and treatment.
Raal Frederick J,Santos Raul D
Atherosclerosis
Homozygous familial hypercholesterolemia (HoFH) is an autosomal co-dominant disease resulting from mutations in both copies of the low-density lipoprotein receptor (LDLR) gene. Mutations in 3 other associated genes, proprotein convertase subtilisin/kexin type 9, apolipoprotein B (APOB), and, more rarely, the autosomal recessive hypercholesterolemia adaptor protein, may lead to a similar phenotype with varying severity. HoFH patients have aggressive cardiovascular disease that develops from birth due to severe LDLR defects, resulting, in turn, in excess production of Apo B-containing atherogenic lipoproteins (low-density lipoprotein [LDL] and lipoprotein(a)). The condition is characterized by exceptionally high LDL cholesterol levels, cutaneous and tendon xanthomas, and valvular and supravalvular stenosis, and accelerated atherosclerosis often manifests in the first 2 decades of life. Treatment typically involves lipid-modifying medical therapy as well as mechanical removal of plasma LDL by means of apheresis. Although statins have afforded survival into the third and fourth decades of life, further therapeutic advancements currently under investigation promise hope of further improvements in survival and improved quality of life. The purpose of this review is to provide current perspectives on diagnosis and therapy in an effort to encourage early recognition and treatment of this rare but severe disease.
10.1016/j.atherosclerosis.2012.02.019
The small GTPase RAB10 regulates endosomal recycling of the LDL receptor and transferrin receptor in hepatocytes.
Journal of lipid research
The low-density lipoprotein receptor (LDLR) mediates the hepatic uptake of circulating low-density lipoproteins (LDLs), a process that modulates the development of atherosclerotic cardiovascular disease. We recently identified RAB10, encoding a small GTPase, as a positive regulator of LDL uptake in hepatocellular carcinoma cells (HuH7) in a genome-wide CRISPR screen, though the underlying molecular mechanism for this effect was unknown. We now report that RAB10 regulates hepatocyte LDL uptake by promoting the recycling of endocytosed LDLR from RAB11-positive endosomes to the plasma membrane. We also show that RAB10 similarly promotes the recycling of the transferrin receptor, which binds the transferrin protein that mediates the transport of iron in the blood, albeit from a distinct RAB4-positive compartment. Taken together, our findings suggest a model in which RAB10 regulates LDL and transferrin uptake by promoting both slow and rapid recycling routes for their respective receptor proteins.
10.1016/j.jlr.2022.100248
Severe xanthomatosis in heterozygous familial hypercholesterolemia.
Aljenedil Sumayah,Ruel Isabelle,Watters Kevin,Genest Jacques
Journal of clinical lipidology
BACKGROUND:Familial hypercholesterolemia is a genetic lipoprotein disorder characterized by elevated plasma low-density lipoprotein cholesterol level, (tendinous xanthomas, xanthelasmas, and premature arcus corneus) and early onset atherosclerotic cardiovascular disease. Familial hypercholesterolemia is caused by mutations in the low-density lipoprotein receptor, apolipoprotein B or proprotein convertase subtilisin/kexin type 9 genes. Rare mutations in low-density lipoprotein receptor adapter protein 1, APOE p.Leu167del or lysosomal acid lipase genes can mimic FH. The prevalence of heterozygous familial hypercholesterolemia is estimated to be 1/250 worldwide, although some populations with founder effects show a higher prevalence. The rare homozygous form has an estimated prevalence of 0.000004 or 1/250,000 and is characterized by markedly elevated low-density lipoprotein cholesterol, skin manifestations (planar xanthomas, tendinous xanthomas) in childhood and extremely premature atherosclerotic cardiovascular disease. While tendinous xanthomas are considered pathognomonic for familial hypercholesterolemia, they can also be found in rare diseases, including sitosterolemia. Here, we report a case of severe tendinous xanthomatosis with heterozygous familial hypercholesterolemia due to the low-density lipoprotein receptor del >15 kb mutation. The phenotypic expression of the disease is out of proportion with the genetic diagnosis or biochemical measurements. CASE REPORT:We report the case of 51-year-old woman of French-Canadian origin diagnosed with heterozygous familial hypercholesterolemia since age 12. She presented with hypercholesterolemia with total cholesterol 7.6 mmol/L, with an imputed low-density lipoprotein cholesterol level of 6.5 mmol/L. She had extensive tendinous xanthomas of the Achilles tendons, knees, elbows and metacarpophalangeal joints. Because of cosmetic disfigurement, she had multiple excisions of Achilles, knee and elbow xanthomas, albeit with rapid recurrence. Our patient has a significant family history of lung cancer and other autoimmune diseases associated with familial hypercholesterolemia and xanthoma. Lipid-lowering therapy was started, at age 12; which included initially cholestyramine, then changed to statin and ezetimibe. Eventually, evolocumab was added. Despite trying different lipid-lowering therapy, there has been no noticeable decrease in the size of the xanthomas. CONCLUSION:Our patient has severe xanthomatosis out of proportion with the genetic diagnosis or biochemical measurements. Her xanthomatosis did not improve by pharmacological therapy consisting of statins and evolocumab despite a 50% reduction in low-density lipoprotein cholesterol. It is likely that the patient presented here has a second genetic disorder that leads to extensive xanthomatosis.
10.1016/j.jacl.2018.03.087
Germinated Brown Rice Attenuates Atherosclerosis and Vascular Inflammation in Low-Density Lipoprotein Receptor-Knockout Mice.
Zhao Ruozhi,Ghazzawi Nora,Wu Jiansu,Le Khuong,Li Chunyang,Moghadasian Mohammed H,Siow Yaw L,Apea-Bah Franklin B,Beta Trust,Yin Zhengfeng,Shen Garry X
Journal of agricultural and food chemistry
The present study investigates the impact of germinated brown rice (GBR) on atherosclerosis and the underlying mechanism in low-density lipoprotein receptor-knockout (LDLr-KO) mice. The intensity of atherosclerosis in aortas of LDLr-KO mice receiving diet supplemented with 60% GBR (weight/weight) was significantly less than that in mice fed with 60% white rice (WR) or control diet ( p < 0.05); all diets contained 0.06% cholesterol. WR or GBR diet did not significantly alter plasma total or LDL-cholesterol, fecal sterols, or glucose, or the activities of antioxidant enzymes, compared to the control diet. The adhesion of monocytes to aortas from LDLr-KO mice fed with WR diet was significantly more than that from mice receiving the control diet ( p < 0.01). GBR diet decreased monocyte adhesion to aortas compared to WR diet ( p < 0.01). GBR diet also reduced the levels of plasminogen activator inhibitor-1 (PAI-1), monocyte chemotactic protein-1 (MCP-1), and tumor necrosis factor-α (TNF-α) in plasma, and the abundances of MCP-1, PAI-1, TNF-α, intracellular cell adhesion molecule-1, toll-like receptor-4, PAI-1, LDLr-like protein, and urokinase plasminogen activator and its receptor in aortas or hearts from LDLr-KO mice in comparison to the WR diet ( p < 0.05, 0.01, respectively). The findings suggest that GBR administration attenuated atherosclerosis and vascular inflammation in LDLr-KO mice compared to WR. The anti-atherosclerotic effect of GBR in LDLr-KO mice at least in part results from its anti-inflammatory activity.
10.1021/acs.jafc.8b00005
LOX-1 variants modulate the severity of cardiovascular disease: state of the art and future directions.
Molecular and cellular biochemistry
Atherosclerosis is one of the major causes of cerebral infarction and many other ischemic cardio-cerebrovascular diseases. Although large randomized clinical trials have highlighted the impressive benefits of lipid-lowering therapies, the 50-70% of patients who have achieved their lipid-lowering goal remain at high cardiovascular disease risk. For this reason, there is a need to investigate other markers of atherosclerosis progression. LOX-1 is a scavenger receptor that accepts oxidized low-density lipoproteins as major ligand and internalizes it by endocytosis favoring its retention in subendothelial layer and triggering a wide variety of proatherogenic events. However, other factors such as cytokines, shear stress, and advanced glycation end-products can upregulate LOX-1. LOX-1 is encoded by the OLR1 gene, located in the p12.3-p13 region of chromosome 12. OLR1 gene has different isoforms induced by splicing, or single-nucleotide polymorphisms (SNPs). According to some authors, the expression of these isoforms induces a different effect on atherosclerosis and cardiovascular disease. In particular, LOXIN, an isoform lacking part of the functional domain, exerts an important role in atherosclerosis protection. In other cases, studies on SNPs showed an association with more severe forms, like in the case of 3'UTR polymorphisms. The knowledge of these variants can give rise to the development of new preventive therapies and can lead to the identification of subjects at greater risk of cardiovascular event. In this review, we reported the state of the art regarding SNPs with known effects on OLR1 splicing and how LOX-1 variants modulate the severity of cardiovascular disease.
10.1007/s11010-023-04859-0
Reducing elevated plasma LDL cholesterol: the central role of the LDL receptor.
Vincent J
Clinical pharmacology and therapeutics
Elevated low-density lipoprotein cholesterol (LDL-C) is an established risk factor for cardiovascular disease (CVD), and reduction of elevated LDL-C reduces mortality in patients at risk. This benefit has evolved from the use of statins and knowledge of the LDL receptor (LDLR). The most potent drugs used for dyslipidemias act by mechanisms that involve this receptor. Advances in molecular genetics and understanding of the regulation of this receptor have revealed several pharmacological targets that are being explored to develop more targeted therapies for dyslipidemias.
10.1038/clpt.2014.95
Mouse Model of Heart Failure With Preserved Ejection Fraction Driven by Hyperlipidemia and Enhanced Cardiac Low-Density Lipoprotein Receptor Expression.
Journal of the American Heart Association
Background The pathways of diastolic dysfunction and heart failure with preserved ejection fraction driven by lipotoxicity with metabolic syndrome are incompletely understood. Thus, there is an urgent need for animal models that accurately mimic the metabolic and cardiovascular phenotypes of this phenogroup for mechanistic studies. Methods and Results Hyperlipidemia was induced in WT-129 mice by 4 weeks of biweekly poloxamer-407 intraperitoneal injections with or without a single intravenous injection of adeno-associatedvirus 9-cardiac troponin T-low-density lipoprotein receptor (n=31), or single intravenous injection with adeno-associatedvirus 9-cardiac troponin T-low-density lipoprotein receptor alone (n=10). Treatment groups were compared with untreated or placebo controls (n=37). Echocardiography, blood pressure, whole-body plethysmography, ECG telemetry, activity wheel monitoring, and biochemical and histological changes were assessed at 4 to 8 weeks. At 4 weeks, double treatment conferred diastolic dysfunction, preserved ejection fraction, and increased left ventricular wall thickness. Blood pressure and whole-body plethysmography results were normal, but respiration decreased at 8 weeks (<0.01). ECG and activity wheel monitoring, respectively, indicated heart block and decreased exercise activity (<0.001). Double treatment promoted elevated myocardial lipids including total cholesterol, fibrosis, increased wet/dry lung (<0.001) and heart weight/body weight (<0.05). Xanthelasma, ascites, and cardiac ischemia were evident in double and single (p407) groups. Sudden death occurred between 6 and 12 weeks in double and single (p407) treatment groups. Conclusions We present a novel model of heart failure with preserved ejection fraction driven by dyslipidemia where mice acquire diastolic dysfunction, arrhythmia, cardiac hypertrophy, fibrosis, pulmonary congestion, exercise intolerance, and preserved ejection fraction in the absence of obesity, hypertension, kidney disease, or diabetes. The model can be applied to dissect pathways of metabolic syndrome that drive diastolic dysfunction in this lipotoxicity-mediated heart failure with preserved ejection fraction phenogroup mimic.
10.1161/JAHA.122.027216
Human Angiopoietin-like Protein 3/ANGPTL3 Antibodies: Adding to the Armamentarium in the Management of Dyslipidemia.
Wiggins Barbara S
Journal of cardiovascular pharmacology
ABSTRACT:Cardiovascular (CV) disease remains the leading cause of death in the United States. In addition to lifestyle modifications, current guidelines primarily focus on lowering low-density lipoprotein cholesterol (LDL-C) to reduce atherosclerotic CV disease risk. However, despite aggressive management, a degree of residual risk remains, suggesting that focusing on lowering LDL-C alone may be inadequate and that other lipid parameters may need to be targeted. In patients who remain at high risk despite current pharmacologic options either because of inadequate response, elevated levels of other lipoproteins, or those who have genetic variants predisposing them to atherosclerotic CV disease, additional treatment strategies continue to be sought. One such group is the homozygous familial hypercholesterolemia population, especially those patients carrying the null low-density lipoprotein receptor mutation as they often fail to derive the same benefit from traditional LDL-C lower strategies such as statins and proprotein convertase subtilisin/kexin type 9 inhibitors that work by upregulating the LDL receptor. Emerging data also suggest that patients with increased levels of triglyceride-rich lipoproteins are also at increased risk as elevated levels are proposed to have a role in various pathways promoting atherogenesis. Angiopoietin-life protein 3 (ANGLTPL3) has recently become a target of interest because of the discovery that inhibiting its action leads to reductions in lipid parameters. Although the mechanism of action of ANGLTPL3 inhibitors is independent of the LDL receptor, their ability to significantly lower triglycerides and LDL-C make them an attractive option particularly in patients with homozygous familial hypercholesterolemia and hypertriglyceridemia. The efficacy and safety of 2 ANGLTPL3 inhibitor agents have been evaluated in clinical trials. In this review, the lipid lowering, metabolic effects, and safety are reported. Ongoing trials assessing CV outcomes as well as long-term safety data are still needed to provide a more definitive role for these agents in the overall management in these populations.
10.1097/FJC.0000000000001132
The Microbiota Promotes Arterial Thrombosis in Low-Density Lipoprotein Receptor-Deficient Mice.
Kiouptsi Klytaimnistra,Jäckel Sven,Pontarollo Giulia,Grill Alexandra,Kuijpers Marijke J E,Wilms Eivor,Weber Christian,Sommer Felix,Nagy Magdolna,Neideck Carlos,Jansen Yvonne,Ascher Stefanie,Formes Henning,Karwot Cornelia,Bayer Franziska,Kollar Bettina,Subramaniam Saravanan,Molitor Michael,Wenzel Philip,Rosenstiel Philip,Todorov Hristo,Gerber Susanne,Walter Ulrich,Jurk Kerstin,Heemskerk Johan W M,van der Vorst Emiel P C,Döring Yvonne,Reinhardt Christoph
mBio
Atherosclerotic plaque development depends on chronic inflammation of the arterial wall. A dysbiotic gut microbiota can cause low-grade inflammation, and microbiota composition was linked to cardiovascular disease risk. However, the role of this environmental factor in atherothrombosis remains undefined. To analyze the impact of gut microbiota on atherothrombosis, we rederived low-density lipoprotein receptor-deficient ( ) mice as germfree (GF) and kept these mice for 16 weeks on an atherogenic high-fat Western diet (HFD) under GF isolator conditions and under conventionally raised specific-pathogen-free conditions (CONV-R). In spite of reduced diversity of the cecal gut microbiome, caused by atherogenic HFD, GF mice and CONV-R mice exhibited atherosclerotic lesions of comparable sizes in the common carotid artery. In contrast to HFD-fed mice, showing no difference in total cholesterol levels, CONV-R mice fed control diet (CD) had significantly reduced total plasma cholesterol, very-low-density lipoprotein (VLDL), and LDL levels compared with GF mice. Myeloid cell counts in blood as well as leukocyte adhesion to the vessel wall at the common carotid artery of GF mice on HFD were diminished compared to CONV-R controls. Plasma cytokine profiling revealed reduced levels of the proinflammatory chemokines CCL7 and CXCL1 in GF mice, whereas the T-cell-related interleukin 9 (IL-9) and IL-27 were elevated. In the atherothrombosis model of ultrasound-induced rupture of the common carotid artery plaque, thrombus area was significantly reduced in GF mice relative to CONV-R mice. , this atherothrombotic phenotype was explained by decreased adhesion-dependent platelet activation and thrombus growth of HFD-fed GF mice on type III collagen. Our results demonstrate a functional role for the commensal microbiota in atherothrombosis. In a ferric chloride injury model of the carotid artery, GF C57BL/6J mice had increased occlusion times compared to colonized controls. Interestingly, in late atherosclerosis, HFD-fed GF mice had reduced plaque rupture-induced thrombus growth in the carotid artery and diminished thrombus formation under arterial flow conditions.
10.1128/mBio.02298-19
Atherosclerosis Development and Progression: The Role of Atherogenic Small, Dense LDL.
Vekic Jelena,Zeljkovic Aleksandra,Cicero Arrigo F G,Janez Andrej,Stoian Anca Pantea,Sonmez Alper,Rizzo Manfredi
Medicina (Kaunas, Lithuania)
Atherosclerosis is responsible for large cardiovascular mortality in many countries globally. It has been shown over the last decades that the reduction of atherosclerotic progression is a critical factor for preventing future cardiovascular events. Low-density lipoproteins (LDL) have been successfully targeted, and their reduction is one of the key preventing measures in patients with atherosclerotic disease. LDL particles are pivotal for the formation and progression of atherosclerotic plaques; yet, they are quite heterogeneous, and smaller, denser LDL species are the most atherogenic. These particles have greater arterial entry and retention, higher susceptibility to oxidation, as well as reduced affinity for the LDL receptor. Increased proportion of small, dense LDL particles is an integral part of the atherogenic lipoprotein phenotype, the most common form of dyslipidemia associated with insulin resistance. Recent data suggest that both genetic and epigenetic factors might induce expression of this specific lipid pattern. In addition, a typical finding of increased small, dense LDL particles was confirmed in different categories of patients with elevated cardiovascular risk. Small, dense LDL is an independent risk factor for cardiovascular diseases, which emphasizes the clinical importance of both the quality and the quantity of LDL. An effective management of atherosclerotic disease should take into account the presence of small, dense LDL in order to prevent cardiovascular complications.
10.3390/medicina58020299
Familial hypercholesterolemia: an under-recognized but significant concern in cardiology practice.
Foody JoAnne M
Clinical cardiology
Familial hypercholesterolemia (FH) is a common disorder in which genetic mutations in at least 1 of several genes lead to significantly increased levels of lipoproteins, in particular, low-density lipoprotein cholesterol. Most commonly, mutations in the low-density lipoprotein receptor gene result in high plasma levels of apolipoprotein B-containing lipoproteins (eg, low-density lipoprotein and lipoprotein(a)). High plasma levels of lipoproteins increase the risk of cardiovascular events by as much as 20-fold if left untreated. A 2011 survey of cardiologists performed by the American College of Cardiology (ACC) suggests that there is a need for greater awareness of FH among cardiologists with regard to its prevalence and heritability, and of the risk of cardiovascular (CV) disease associated with the disorder, such as premature coronary heart disease. Given that many patients with FH may first present to CV specialists at the time of a major coronary event, it is critical that cardiologists have strategies to manage this high-risk subset of patients. This brief review responds to areas of need identified in the ACC survey and is intended to provide current information about FH and increase awareness about this disorder among cardiologists.
10.1002/clc.22223
Therapeutic Targeting of LRP6 in Cardiovascular Diseases: Challenging But Not Wnt-Possible!
Labbé Pauline,Thorin Eric
The Canadian journal of cardiology
Coronary artery disease (CAD), often related to dyslipidemia, is a major cause of death worldwide, highlighting unmet therapeutic needs. Lipoprotein receptor-related protein 6 (LRP6) is a member of the low-density lipoprotein receptor (LDLR) family composed of structurally related cell surface receptors and acts, in consort with Frizzled receptors, as a coreceptor to mediate the Wnt/β-catenin signalling pathway. Impaired LRP6 signalling in humans has been associated with multiple cardiovascular risk factors such as elevated serum LDL, triglycerides, and glucose levels. Considerable efforts have been deployed to better understand the underlying mechanisms of LRP6-associated disorders, and the therapeutic targeting of LRP6 has been demonstrated to have positive effects in various animal models of cardiovascular disease. This review presents a synthetic summary highlighting the major roles of LRP6. LRP6 regulates a multitude of cellular mechanisms dependently or independently of the β-catenin pathway, as LRP6 activates gene transcription, regulates crucial cellular events such as cell cycle or protein synthesis, and even modulates gap junctional coupling in cardiomyocytes and LDLR recycling in hepatocytes. We discuss the potential contribution of LRP6 as a therapeutic target, as LRP6 inhibition limits myocardial fibrosis and promotes cardiac repair in myocardial infarction, limits neointimal formation in carotid injury models, decreases blood pressure in hypertensive animals, and reduces adipogenesis and lipogenesis to prevent hypercholesterolemia and atherosclerosis. These findings from past studies highlight LRP6 as a key player in the development of heart disease and a promising therapeutic target for cardiovascular disease in humans.
10.1016/j.cjca.2019.06.030
Triglyceride Rich Lipoprotein -LPL-VLDL Receptor and Lp(a)-VLDL Receptor Pathways for Macrophage Foam Cell Formation.
Takahashi Sadao
Journal of atherosclerosis and thrombosis
Very low-density lipoprotein (VLDL) receptor is a member of the low-density lipoprotein (LDL) receptor family. It binds triglyceride rich lipoprotein (TGRL) but not LDL, because it recognizes apolipoprotein (apo)E only but not apoB. The VLDL receptor functions as a peripheral lipoprotein receptor in concert with lipoprotein lipase (LPL) in heart, muscle, adipose tissue and macrophages. In contrast to the LDL receptor, VLDL receptor binds apo E2/2 VLDL and apoE3/3 VLDL particles, and its expression is not down-regulated by intracellular lipoproteins. It has been reported that both LDL-cholesterol (LDL-C) and postprandial triglyceride (chyromicron and VLDL remnants) are risk factors for human atherosclerotic cardiovascular disease (ASCVD). True ligands such as lipoprotein particles of the VLDL receptor are chyromicron remnant (CMR) and VLDL remnant (postprandial hyperlipidemia). Although the oxidized LDL (oxLDL)-scavenger receptors pathway is considered to be the main mechanism for macrophage foam cell formation, it seems that the TGRL-LPL-VLDL receptor pathway is also involved. Since Lp(a) is one of the ligands for the VLDL receptor, the Lp(a)-VLDL receptor pathway is another potential alternative. The expression of VLDL receptor protein in mouse macrophages is modest compared to that in rabbit and human macrophages, both in vitro and in vivo. Therefore, we need to elucidate the mechanism of human ASCVD not by using the mouse model and scavenger receptors pathway but instead using the rabbit model and VLDL receptor pathway, respectively.
10.5551/jat.RV17004
Inhibition of low-density lipoprotein uptake by Helicobacter pylori virulence factor CagA.
Ninomiya Ryo,Kubo Shuichi,Baba Takehiro,Kajiwara Tooru,Tokunaga Akinori,Nabeka Hiroaki,Doihara Takuya,Shimokawa Tetsuya,Matsuda Seiji,Murakami Kazunari,Aigaki Toshiro,Yamaoka Yoshio,Hamada Fumihiko
Biochemical and biophysical research communications
Helicobacter pylori (H. pylori) infection mainly causes gastroduodenal diseases, including chronic gastritis, peptic ulcer disease and gastric cancer. In recent years, several studies have demonstrated that infection with H. pylori, especially strains harboring the virulence factor CagA (cytotoxin-associated gene A), contribute to the development of non-gastric systemic diseases, including hypercholesterolemia and atherosclerotic cardiovascular diseases. However, mechanisms underlying this association has not been defined. In this study, we carried out a large-scale genetic screen using Drosophila and identified a novel CagA target low-density lipoprotein receptor (LDLR), which aids in the clearance of circulating LDL. We showed that CagA physically interacted with LDLR via its carboxy-terminal region and inhibited LDLR-mediated LDL uptake into cells. Since deficiency of LDLR-mediated LDL uptake has been known to increase plasma LDL and accelerate atherosclerosis, our findings may provide a novel mechanism for the association between infection with CagA-positive H. pylori and hypercholesterolemia leading to atherosclerotic cardiovascular diseases.
10.1016/j.bbrc.2021.03.170
Low-density lipoprotein receptor-related protein 1 (LRP1) is a novel receptor for apolipoprotein A4 (APOA4) in adipose tissue.
Qu Jie,Fourman Sarah,Fitzgerald Maureen,Liu Min,Nair Supna,Oses-Prieto Juan,Burlingame Alma,Morris John H,Davidson W Sean,Tso Patrick,Bhargava Aditi
Scientific reports
Apolipoprotein A4 (APOA4) is one of the most abundant and versatile apolipoproteins facilitating lipid transport and metabolism. APOA4 is synthesized in the small intestine, packaged onto chylomicrons, secreted into intestinal lymph and transported via circulation to several tissues, including adipose. Since its discovery nearly 4 decades ago, to date, only platelet integrin αIIbβ3 has been identified as APOA4 receptor in the plasma. Using co-immunoprecipitation coupled with mass spectrometry, we probed the APOA4 interactome in mouse gonadal fat tissue, where ApoA4 gene is not transcribed but APOA4 protein is abundant. We demonstrate that lipoprotein receptor-related protein 1 (LRP1) is the cognate receptor for APOA4 in adipose tissue. LRP1 colocalized with APOA4 in adipocytes; it interacted with APOA4 under fasting condition and their interaction was enhanced during lipid feeding concomitant with increased APOA4 levels in plasma. In 3T3-L1 mature adipocytes, APOA4 promoted glucose uptake both in absence and presence of insulin in a dose-dependent manner. Knockdown of LRP1 abrogated APOA4-induced glucose uptake as well as activation of phosphatidylinositol 3 kinase (PI3K)-mediated protein kinase B (AKT). Taken together, we identified LRP1 as a novel receptor for APOA4 in promoting glucose uptake. Considering both APOA4 and LRP1 are multifunctional players in lipid and glucose metabolism, our finding opens up a door to better understand the molecular mechanisms along APOA4-LRP1 axis, whose dysregulation leads to obesity, cardiovascular disease, and diabetes.
10.1038/s41598-021-92711-0
The interplay of canonical and noncanonical Wnt signaling in metabolic syndrome.
Abou Ziki Maen D,Mani Arya
Nutrition research (New York, N.Y.)
Metabolic syndrome is a cluster of inherited metabolic traits, which centers around obesity and insulin resistance and is a major contributor to the growing prevalence of cardiovascular disease. The factors that underlie the association of metabolic traits in this syndrome are poorly understood due to disease heterogeneity and complexity. Genetic studies of kindreds with severe manifestation of metabolic syndrome have led to the identification of casual rare mutations in the LDL receptor-related protein 6, which serves as a co-receptor with frizzled protein receptors for Wnt signaling ligands. Extensive investigations have since unraveled the significance of the Wnt pathways in regulating body mass, glucose metabolism, de novo lipogenesis, low-density lipoprotein clearance, vascular smooth muscle plasticity, liver fat, and liver inflammation. The impaired canonical Wnt signaling observed in the R611C mutation carriers and the ensuing activation of noncanonical Wnt signaling constitute the underlying mechanism for these cardiometabolic abnormalities. Transcription factor 7-like 2 is a key transcription factor activated through LDL receptor-related protein 6 canonical Wnt and reciprocally inhibited by the noncanonical pathway. TC7L2 increases insulin receptor expression, decreases low-density lipoprotein and triglyceride synthesis, and inhibits vascular smooth muscle proliferation. Canonical Wnt also inhibits noncanonical protein kinase C, Ras homolog gene family member A, and Rho associated coiled-coil containing protein kinase 2 activation, thus inhibiting steatohepatitis and transforming growth factor β-mediated extracellular matrix deposition and hepatic fibrosis. Therefore, dysregulation of the highly conserved Wnt signaling pathway underlies the pleiotropy of metabolic traits of the metabolic syndrome and the subsequent end-organ complications.
10.1016/j.nutres.2018.06.009
LOX-1 in Atherosclerosis and Myocardial Ischemia: Biology, Genetics, and Modulation.
Pothineni Naga Venkata K,Karathanasis Sotirios K,Ding Zufeng,Arulandu Arockiasamy,Varughese Kottayil I,Mehta Jawahar L
Journal of the American College of Cardiology
Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), one of the scavenger receptors for oxidized low-density lipoprotein cholesterol (ox-LDL), plays a crucial role in the uptake of ox-LDL by cells in the arterial wall. Mounting evidence suggests a role for LOX-1 in various steps of the atherosclerotic process, from initiation to plaque destabilization. Studies of the genetic structure of LOX-1 have also uncovered various genetic polymorphisms that could modulate the risk of atherosclerotic cardiovascular events. As evidence supporting the vital role of LOX-1 in atherogenesis keeps accumulating, there is growing interest in LOX-1 as a potential therapeutic target. This review discusses the discovery and genetics of LOX-1; describes existing evidence supporting the role of LOX-1 in atherogenesis and its major complication, myocardial ischemia; and summarizes LOX-1 modulation by some naturally occurring compounds and efforts toward development of small molecules and biologics that could be of therapeutic use.
10.1016/j.jacc.2017.04.010
SR-B1, a Key Receptor Involved in the Progression of Cardiovascular Disease: A Perspective from Mice and Human Genetic Studies.
Biomedicines
High plasma level of low-density lipoprotein (LDL) is the main driver of the initiation and progression of cardiovascular disease (CVD). Nevertheless, high-density lipoprotein (HDL) is considered an anti-atherogenic lipoprotein due to its role in reverse cholesterol transport and its ability to receive cholesterol that effluxes from macrophages in the artery wall. The scavenger receptor B class type 1 (SR-B1) was identified as the high-affinity HDL receptor, which facilitates the selective uptake of cholesterol ester (CE) into the liver via HDL and is also implicated in the plasma clearance of LDL, very low-density lipoprotein (VLDL) and lipoprotein(a) (Lp(a)). Thus, SR-B1 is a multifunctional receptor that plays a main role in the metabolism of different lipoproteins. The aim of this review is to highlight the association between SR-B1 and CVD risk through mice and human genetic studies.
10.3390/biomedicines9060612
Targeting LOX-1 in atherosclerosis and vasculopathy: current knowledge and future perspectives.
Tian Kunming,Ogura Sayoko,Little Peter J,Xu Suo-Wen,Sawamura Tatsuya
Annals of the New York Academy of Sciences
LOX-1 (lectin-like oxidized low-density lipoprotein receptor-1; also known as OLR1) is the dominant receptor that recognizes and internalizes oxidized low-density lipoproteins (ox-LDLs) in endothelial cells. Several genetic variants of LOX-1 are associated with the risk and severity of coronary artery disease. The LOX-1-ox-LDL interaction induces endothelial dysfunction, leukocyte adhesion, macrophage-derived foam cell formation, smooth muscle cell proliferation and migration, and platelet activation. LOX-1 activation eventually leads to the rupture of atherosclerotic plaques and acute cardiovascular events. In addition, LOX-1 can be cleaved to generate soluble LOX-1 (sLOX-1), which is a useful diagnostic and prognostic marker for atherosclerosis-related diseases in human patients. Of therapeutic relevance, several natural products and clinically used drugs have emerged as LOX-1 inhibitors that have antiatherosclerotic actions. We hereby provide an updated overview of role of LOX-1 in atherosclerosis and associated vascular diseases, with an aim to highlighting the potential of LOX-1 as a novel theranostic tool for cardiovascular disease prevention and treatment.
10.1111/nyas.13984
VLDL receptor gene therapy for reducing atherogenic lipoproteins.
Molecular metabolism
Over the past 40 years, there has been considerable research into the management and treatment of atherogenic lipid disorders. Although the majority of treatments and management strategies for cardiovascular disease (CVD) center around targeting low-density lipoprotein cholesterol (LDL-C), there is mounting evidence for the residual CVD risk attributed to high triglyceride (TG) and lipoprotein(a) (Lp(a)) levels despite the presence of lowered LDL-C levels. Among the biological mechanisms for clearing TG-rich lipoproteins, the VLDL receptor (VLDLR) plays a key role in the trafficking and metabolism of lipoprotein particles in multiple tissues, but it is not ordinarily expressed in the liver. Since VLDLR is capable of binding and internalizing apoE-containing TG-rich lipoproteins as well as Lp(a), hepatic VLDLR expression has the potential for promoting clearance of these atherogenic particles from the circulation and managing the residual CVD risk not addressed by current lipid lowering therapies. This review provides an overview of VLDLR function and the potential for developing a genetic medicine based on liver-targeted VLDLR gene expression.
10.1016/j.molmet.2023.101685
The LDL receptor: Traffic and function in trophoblast cells under normal and pathological conditions.
Placenta
During pregnancy, the developing foetus requires large amounts of cholesterol from the maternal plasma, which is mediated by proteins such as the receptor for low-density lipoproteins (LDLR). The quantity of LDLR available in the syncytiotrophoblast plasma membrane is an important factor for the uptake, metabolism, and transfer of cholesterol to foetal circulation. Because of the relevance of this receptor for cellular and systemic cholesterol metabolism in non-placental cells, the study of mechanisms associated with LDLR trafficking, such as the availability in the cell membrane, endocytosis, recycling, sorting, and degradation, have been extensively studied. Multiple protein groups are required for proper LDL/LDLR trafficking. Changes in the function of these proteins are related to hypercholesterolemia, the main risk factor associated with cardiovascular disease. It is well known that the placenta plays an essential role as a barrier between maternal lipids and the foetus and that imbalances in maternal cholesterol levels during pregnancy are frequent and associated with cardiovascular disease in the offspring. However, there is little information regarding lipoprotein trafficking in this system. In this review, we summarize the available information on LDLR trafficking, emphasizing the few reports related to receptor biology in placental cells from normal and pathological pregnancies. We conclude that extensive research on the cell biology of the placenta is required to unravel the endocytic trafficking of proteins such as LDLR in a highly specialized cell such as the syncytiotrophoblast.
10.1016/j.placenta.2022.07.013
Screening and Identification of ssDNA Aptamers for Low-Density Lipoprotein (LDL) Receptor-Related Protein 6.
Molecules (Basel, Switzerland)
Low-density lipoprotein receptor-related protein 6 (LRP6), a member of the low-density lipoprotein receptor (LDLR) family, displays a unique structure and ligand-binding function. As a co-receptor of the Wnt/β-catenin signaling pathway, LRP6 is a novel therapeutic target that plays an important role in the regulation of cardiovascular disease, lipid metabolism, tumorigenesis, and some classical signals. By using capillary electrophoresis-systematic evolution of ligands by exponential enrichment (CE-SELEX), with recombinant human LRP-6 as the target, four candidate aptamers with a stem-loop structure were selected from an ssDNA library-AptLRP6-A1, AptLRP6-A2, AptLRP6-A3, and AptLRP6-A4. The equilibrium dissociation constant values between these aptamers and the LRP6 protein were in the range of 0.105 to 1.279 μmol/L, as determined by CE-LIF analysis. Their affinities and specificities were further determined by the gold nanoparticle (AuNP) colorimetric method. Among them, AptLRP6-A3 showed the highest affinity with LRP6-overexpressed human breast cancer cells. Therefore, the LRP6 aptamer identified in this study constitutes a promising modality for the rapid diagnosis and treatment of LRP6-related diseases.
10.3390/molecules28093838
Update on the molecular biology of dyslipidemias.
Ramasamy I
Clinica chimica acta; international journal of clinical chemistry
Dyslipidemia is a commonly encountered clinical condition and is an important determinant of cardiovascular disease. Although secondary factors play a role in clinical expression, dyslipidemias have a strong genetic component. Familial hypercholesterolemia is usually due to loss-of-function mutations in LDLR, the gene coding for low density lipoprotein receptor and genes encoding for proteins that interact with the receptor: APOB, PCSK9 and LDLRAP1. Monogenic hypertriglyceridemia is the result of mutations in genes that regulate the metabolism of triglyceride rich lipoproteins (eg LPL, APOC2, APOA5, LMF1, GPIHBP1). Conversely familial hypobetalipoproteinemia is caused by inactivation of the PCSK9 gene which increases the number of LDL receptors and decreases plasma cholesterol. Mutations in the genes APOB, and ANGPTL3 and ANGPTL4 (that encode angiopoietin-like proteins which inhibit lipoprotein lipase activity) can further cause low levels of apoB containing lipoproteins. Abetalipoproteinemia and chylomicron retention disease are due to mutations in the microsomal transfer protein and Sar1b-GTPase genes, which affect the secretion of apoB containing lipoproteins. Dysbetalipoproteinemia stems from dysfunctional apoE and is characterized by the accumulation of remnants of chylomicrons and very low density lipoproteins. ApoE deficiency can cause a similar phenotype or rarely mutations in apoE can be associated with lipoprotein glomerulopathy. Low HDL can result from mutations in a number of genes regulating HDL production or catabolism; apoAI, lecithin: cholesterol acyltransferase and the ATP-binding cassette transporter ABCA1. Patients with cholesteryl ester transfer protein deficiency have markedly increased HDL cholesterol. Both common and rare genetic variants contribute to susceptibility to dyslipidemias. In contrast to rare familial syndromes, in most patients, dyslipidemias have a complex genetic etiology consisting of multiple genetic variants as established by genome wide association studies. Secondary factors, obesity, metabolic syndrome, diabetes, renal disease, estrogen and antipsychotics can increase the likelihood of clinical presentation of an individual with predisposed genetic susceptibility to hyperlipoproteinemia. The genetic profiles studied are far from complete and there is room for further characterization of genes influencing lipid levels. Genetic assessment can help identify patients at risk for developing dyslipidemias and for treatment decisions based on 'risk allele' profiles. This review will present the current information on the genetics and pathophysiology of disorders that cause dyslipidemias.
10.1016/j.cca.2015.10.033
Macrophages and T cells in atherosclerosis: a translational perspective.
Bartlett Benjamin,Ludewick Herbert P,Misra Ashish,Lee Silvia,Dwivedi Girish
American journal of physiology. Heart and circulatory physiology
Atherosclerosis is now considered a chronic maladaptive inflammatory disease. The hallmark feature in both human and murine disease is atherosclerotic plaques. Macrophages and various T-cell lineages play a crucial role in atherosclerotic plaque establishment and disease progression. Humans and mice share many of the same processes that occur within atherogenesis. The various similarities enable considerable insight into disease mechanisms and those which contribute to cardiovascular complications. The apolipoprotein E-null and low-density lipoprotein receptor-null mice have served as the foundation for further immunological pathway manipulation to identify pro- and antiatherogenic pathways in attempt to reveal more novel therapeutic targets. In this review, we provide a translational perspective and discuss the roles of macrophages and various T-cell lineages in contrasting proatherosclerotic and atheroprotective settings.
10.1152/ajpheart.00206.2019
The Role of Low-Density Lipoprotein Receptor-Related Protein 1 in Lipid Metabolism, Glucose Homeostasis and Inflammation.
Actis Dato Virginia,Chiabrando Gustavo Alberto
International journal of molecular sciences
Metabolic syndrome (MetS) is a highly prevalent disorder which can be used to identify individuals with a higher risk for cardiovascular disease and type 2 diabetes. This metabolic syndrome is characterized by a combination of physiological, metabolic, and molecular alterations such as insulin resistance, dyslipidemia, and central obesity. The low-density lipoprotein receptor-related protein 1 (LRP1—A member of the LDL receptor family) is an endocytic and signaling receptor that is expressed in several tissues. It is involved in the clearance of chylomicron remnants from circulation, and has been demonstrated to play a key role in the lipid metabolism at the hepatic level. Recent studies have shown that LRP1 is involved in insulin receptor (IR) trafficking and intracellular signaling activity, which have an impact on the regulation of glucose homeostasis in adipocytes, muscle cells, and brain. In addition, LRP1 has the potential to inhibit or sustain inflammation in macrophages, depending on its cellular expression, as well as the presence of particular types of ligands in the extracellular microenvironment. In this review, we summarize existing perspectives and the latest innovations concerning the role of tissue-specific LRP1 in lipoprotein and glucose metabolism, and examine its ability to mediate inflammatory processes related to MetS and atherosclerosis.
10.3390/ijms19061780
Cholesterol in LDL receptor recycling and degradation.
Yang Hui-Xian,Zhang Min,Long Shi-Yin,Tuo Qin-Hui,Tian Ying,Chen Jian-Xiong,Zhang Cai-Ping,Liao Duan-Fang
Clinica chimica acta; international journal of clinical chemistry
The SREBP2/LDLR pathway is sensitive to cholesterol content in the endoplasmic reticulum (ER), while membrane low-density lipoprotein receptor (LDLR) is influenced by sterol response element binding protein 2 (SREBP2), pro-protein convertase subtilisin/kexin type 9 (PCSK9) and inducible degrader of LDLR (IDOL). LDL-C, one of the risk factors in cardiovascular disease, is cleared through endocytosis recycling of LDLR. Therefore, we propose that a balance between LDLR endocytosis recycling and PCSK9-mediated and IDOL-mediated lysosomal LDLR degradation is responsible for cholesterol homeostasis in the ER. For statins that decrease serum LDL-C levels via cholesterol synthesis inhibition, the mechanism by which the statins increase the membrane LDLR may be regulated by cholesterol homeostasis in the ER.
10.1016/j.cca.2019.09.022
Proprotein Convertase Subtilisin/Kexin-Type 9 and Lipid Metabolism.
Guo Shoudong,Xia Xiao-Dan,Gu Hong-Mei,Zhang Da-Wei
Advances in experimental medicine and biology
Plasma levels of cholesterol, especially low-density lipoprotein cholesterol (LDL-C), are positively correlated with the risk of cardiovascular disease. Buildup of LDL in the intima promotes the formation of foam cells and consequently initiates atherosclerosis, one of the main underlying causes of cardiovascular disease. Hepatic LDL receptor (LDLR) is mainly responsible for the clearance of plasma LDL. Mutations in LDLR cause familiar hypercholesterolemia and increase the risk of premature coronary heart disease. Proprotein convertase subtilisin/kexin-type 9 (PCSK9) promotes LDLR degradation and thereby plays a critical role in the regulation of plasma cholesterol metabolism. PCSK9 can bind to LDLR and reroute the receptor to lysosomes for degradation, increasing both circulating LDL-C levels and the risk of cardiovascular disease. PCSK9 is mainly regulated by sterol response element binding protein 2 (SREBP2) at the transcriptional level. Furthermore, many proteins have been identified as interacting with PCSK9, regulating plasma cholesterol levels. Pharmacotherapeutic inhibition of PCSK9 dramatically reduces plasma levels of LDL cholesterol and significantly reduces cardiovascular events. In this article, we summarize the latest advances in PCSK9, mainly focusing on the structure, function, and regulation of the protein, the underlying molecular mechanisms, and its pharmacotherapeutic applications.
10.1007/978-981-15-6082-8_9
Low-Density Lipoprotein Receptor-Related Protein 6 (LRP6) Is a Novel Nutritional Therapeutic Target for Hyperlipidemia, Non-Alcoholic Fatty Liver Disease, and Atherosclerosis.
Go Gwang-woong
Nutrients
Low-density lipoprotein receptor-related protein 6 (LRP6) is a member of the low-density lipoprotein receptor family and has a unique structure, which facilitates its multiple functions as a co-receptor for Wnt/β-catenin signaling and as a ligand receptor for endocytosis. The role LRP6 plays in metabolic regulation, specifically in the nutrient-sensing pathway, has recently garnered considerable interest. Patients carrying an LRP6 mutation exhibit elevated levels of LDL cholesterol, triglycerides, and fasting glucose, which cooperatively constitute the risk factors of metabolic syndrome and atherosclerosis. Since the discovery of this mutation, the general role of LRP6 in lipid homeostasis, glucose metabolism, and atherosclerosis has been thoroughly researched. These studies have demonstrated that LRP6 plays a role in LDL receptor-mediated LDL uptake. In addition, when the LRP6 mutant impaired Wnt-LRP6 signaling, hyperlipidemia, non-alcoholic fatty liver disease, and atherosclerosis developed. LRP6 regulates lipid homeostasis and body fat mass via the nutrient-sensing mechanistic target of the rapamycin (mTOR) pathway. Furthermore, the mutant LRP6 triggers atherosclerosis by activating platelet-derived growth factor (PDGF)-dependent vascular smooth muscle cell differentiation. This review highlights the exceptional opportunities to study the pathophysiologic contributions of LRP6 to metabolic syndrome and cardiovascular diseases, which implicate LRP6 as a latent regulator of lipid metabolism and a novel therapeutic target for nutritional intervention.
10.3390/nu7064453
Recent insights into low-density lipoprotein metabolism and therapy.
Pirillo Angela,Catapano Alberico L,Norata Giuseppe D
Current opinion in clinical nutrition and metabolic care
PURPOSE OF REVIEW:Elevated levels of low-density lipoprotein cholesterol (LDL-C) are causal to atherosclerosis and, thus, the reduction of LDL-C represents a major objective for the prevention of cardiovascular disease. Aim of this review is to provide an overview on novel strategies to lower LDL-C. RECENT FINDINGS:Although inhibiting liver cholesterol biosynthesis by statins is used as the main therapeutic approach to increase hepatic LDL-receptor expression and lower plasma cholesterol levels, novel insights into lipid and lipoprotein biology have led to the development of additional lipid-lowering therapies that can be used in combination with or as an alternative to statins in patients with statin-intolerance. New approaches include bempedoic acid, proprotein convertase subtilisin/kexin type 9 inhibitors, and angiopoietin-like protein 3 inhibitors. SUMMARY:In the last decade, several novel therapeutic approaches have been tested and some of them have been approved as lipid-lowering agents. Some drugs are already available in clinical practice, whereas others are at late stages of development.
10.1097/MCO.0000000000000727
Protein carbamylation and cardiovascular disease.
Verbrugge Frederik H,Tang W H Wilson,Hazen Stanley L
Kidney international
Carbamylation constitutes a posttranslational modification of proteins or amino acids and results from different pathways in vivo. First is the non-enzymatic reaction between isocyanic acid, a decomposition product of urea, and either the N-terminus or the ɛ-amino group of lysine residues. Isocyanic acid levels, while low in vivo, are in equilibrium with urea and are thus increased in chronic and end-stage renal diseases. An alternative pathway involves the leukocyte heme protein myeloperoxidase, which catalyzes the oxidation of thiocyanate in the presence of hydrogen peroxide, producing isocyanate at inflammation sites. Notably, plasma thiocyanate levels are increased in smokers, and leukocyte-driven protein carbamylation occurs both within human and animal atherosclerotic plaques, as well as on plasma proteins. Protein carbamylation is considered a hallmark of molecular aging and is implicated in many pathological conditions. Recently, it has been shown that carbamylated low-density lipoprotein (LDL) induces endothelial dysfunction via lectin-like-oxidized LDL receptor-1 activation and increased reactive oxygen species production, leading to endothelial nitric oxide synthase uncoupling. Moreover, carbamylated LDL harbors atherogenic activities, including both binding to macrophage scavenger receptors inducing cholesterol accumulation and foam-cell formation, as well as promoting vascular smooth muscle proliferation. In contrast, high-density lipoprotein loses its anti-apoptotic activity after carbamylation, contributing to endothelial cell death. In addition to involvement in atherogenesis, protein carbamylation levels have emerged as a particularly strong predictor of both prevalent and incident cardiovascular disease risk. Recent studies also suggest that protein carbamylation may serve as a potential therapeutic target for the prevention of atherosclerotic heart disease.
10.1038/ki.2015.166
Targeting PCSK9 for hypercholesterolemia.
Norata Giuseppe Danilo,Tibolla Gianpaolo,Catapano Alberico Luigi
Annual review of pharmacology and toxicology
Dyslipidemias are a predominant risk factor for cardiovascular disease. Biological and genetic research has led to the identification of several genes and proteins that may be pharmacologically targeted to improve lipoprotein profiles and possibly cardiovascular outcomes in patients with dyslipidemia. The observation that proprotein convertase subtilisin/kexin type 9 (PCSK9) regulates the levels of circulating low-density lipoprotein C (LDL-C) by enhancing the degradation of the hepatic low-density lipoprotein receptor (LDLR) prompted the search for drugs that inhibit PCSK9 activity. Several approaches to inhibiting PCSK9 activity have been proposed; these involve inhibitory antibodies, small molecules, and gene silencing. To date, the most promising and advanced approach relates to monoclonal antibodies, which can decrease LDL cholesterol by 65-70%, even as an add-on therapy to a maximal dose of a statin. Phase III studies and large, event-driven clinical trials are ongoing and will fully address the viability and role of these drugs in clinical practice.
10.1146/annurev-pharmtox-011613-140025
Caffeine blocks SREBP2-induced hepatic PCSK9 expression to enhance LDLR-mediated cholesterol clearance.
Nature communications
Evidence suggests that caffeine (CF) reduces cardiovascular disease (CVD) risk. However, the mechanism by which this occurs has not yet been uncovered. Here, we investigated the effect of CF on the expression of two bona fide regulators of circulating low-density lipoprotein cholesterol (LDLc) levels; the proprotein convertase subtilisin/kexin type 9 (PCSK9) and the low-density lipoprotein receptor (LDLR). Following the observation that CF reduced circulating PCSK9 levels and increased hepatic LDLR expression, additional CF-derived analogs with increased potency for PCSK9 inhibition compared to CF itself were developed. The PCSK9-lowering effect of CF was subsequently confirmed in a cohort of healthy volunteers. Mechanistically, we demonstrate that CF increases hepatic endoplasmic reticulum (ER) Ca levels to block transcriptional activation of the sterol regulatory element-binding protein 2 (SREBP2) responsible for the regulation of PCSK9, thereby increasing the expression of the LDLR and clearance of LDLc. Our findings highlight ER Ca as a master regulator of cholesterol metabolism and identify a mechanism by which CF may protect against CVD.
10.1038/s41467-022-28240-9
Wnt signaling in cardiovascular disease: opportunities and challenges.
Gay Austin,Towler Dwight A
Current opinion in lipidology
PURPOSE OF REVIEW:Cardiometabolic diseases increasingly afflict our aging, dysmetabolic population. Complex signals regulating low-density lipoprotein receptor-related protein (LRP) and frizzled protein family members - the plasma membrane receptors for the cadre of Wnt polypeptide morphogens - contribute to the control of cardiovascular homeostasis. RECENT FINDINGS:Both canonical (β-catenin-dependent) and noncanonical (β-catenin-independent) Wnt signaling programs control vascular smooth muscle (VSM) cell phenotypic modulation in cardiometabolic disease. LRP6 limits VSM proliferation, reduces arteriosclerotic transcriptional reprogramming, and preserves insulin sensitivity while LRP5 restrains foam cell formation. Adipose, skeletal muscle, macrophages, and VSM have emerged as important sources of circulating Wnt ligands that are dynamically regulated during the prediabetes-diabetes transition with cardiometabolic consequences. Platelets release Dkk1, a LRP5/LRP6 inhibitor that induces endothelial inflammation and the prosclerotic endothelial-mesenchymal transition. By contrast, inhibitory secreted frizzled-related proteins shape the Wnt signaling milieu to limit myocardial inflammation with ischemia-reperfusion injury. VSM sclerostin, an inhibitor of canonical Wnt signaling in bone, restrains remodeling that predisposes to aneurysm formation, and is downregulated in aneurysmal vessels by epigenetic methylation. SUMMARY:Components of the Wnt signaling cascade represent novel targets for pharmacological intervention in cardiometabolic disease. Conversely, strategies targeting the Wnt signaling cascade for other therapeutic purposes will have cardiovascular consequences that must be delineated to establish clinically useful pharmacokinetic-pharmacodynamic relationships.
10.1097/MOL.0000000000000445
Sortilin and the risk of cardiovascular disease.
Coutinho Maria Francisca,Bourbon Mafalda,Prata Maria João,Alves Sandra
Revista portuguesa de cardiologia : orgao oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology
Plasma low-density lipoprotein cholesterol (LDL-C) levels are a key determinant of the risk of cardiovascular disease, which is why many studies have attempted to elucidate the pathways that regulate its metabolism. Novel latest-generation sequencing techniques have identified a strong association between the 1p13 locus and the risk of cardiovascular disease caused by changes in plasma LDL-C levels. As expected for a complex phenotype, the effects of variation in this locus are only moderate. Even so, knowledge of the association is of major importance, since it has unveiled a new metabolic pathway regulating plasma cholesterol levels. Crucial to this discovery was the work of three independent teams seeking to clarify the biological basis of this association, who succeeded in proving that SORT1, encoding sortilin, was the gene in the 1p13 locus involved in LDL metabolism. SORT1 was the first gene identified as determining plasma LDL levels to be mechanistically evaluated and, although the three teams used different, though appropriate, experimental methods, their results were in some ways contradictory. Here we review all the experiments that led to the identification of the new pathway connecting sortilin with plasma LDL levels and risk of myocardial infarction. The regulatory mechanism underlying this association remains unclear, but its discovery has paved the way for considering previously unsuspected therapeutic targets and approaches.
10.1016/j.repc.2013.02.006
Cardiovascular disease in familial hypercholesterolaemia: influence of low-density lipoprotein receptor mutation type and classic risk factors.
Alonso R,Mata N,Castillo S,Fuentes F,Saenz P,Muñiz O,Galiana J,Figueras R,Diaz J L,Gomez-Enterría P,Mauri M,Piedecausa M,Irigoyen L,Aguado R,Mata P,
Atherosclerosis
AIM:To determine the effect of the type of mutation in low-density lipoprotein receptor gene and the risk factors associated with the development of premature cardiovascular disease (PCVD) in a large cohort of heterozygous familial hypercholesterolemia (hFH) subjects with genetic diagnosis in Spain. METHODS AND RESULTS:A cross-sectional study was conducted on 811 non-related FH patients (mean age 47.1+/-14 years, 383 males and 428 females) with a molecular defect in the low-density lipoprotein receptor (LDLR) gene from the Spanish National FH Register. Prevalence of PCVD was 21.9% (30.2% in males and 14.5% in women, P<0.001). Mean age of onset of cardiovascular event was 42.1 years in males and 50.8 years in females. Of those patients with PCVD, 59.5% of males and 27% of females suffered a second cardiovascular (CV) event. In multivariate analysis male gender, age, tobacco consumption (ever), and total cholesterol/HDL-cholesterol (TC/HDL-C) ratio were significantly associated with PCVD. Two hundred and twenty different mutations were found with a large heterogeneity. Patients carrying null-mutations had significantly higher frequency of PCVD and recurrence of CV events. No relationship with Lp(a) levels and genotype of Apo E were found. CONCLUSIONS:This study confirms the importance of identifying some classic risk factors such as smoking and TC/HDL-C ratio, and also the type of mutation in LDLR gene in order to implement early detection and intensive treatment for the prevention of cardiovascular disease in FH patients.
10.1016/j.atherosclerosis.2007.12.024
Low-density lipoprotein receptor (LDLR) family orchestrates cholesterol homeostasis.
Go Gwang-Woong,Mani Arya
The Yale journal of biology and medicine
The LDLR family of proteins is involved in lipoproteins trafficking. While the role of LDLR in cardiovascular disease has been widely studied, only recently the role of other members of the LDLR proteins in lipoprotein homeostasis and atherosclerosis has emerged. LDLR, VLDLR, and LRPs bind and internalize apoE- and apoB-containing lipoprotein, including LDL and VLDL, and regulate their cellular uptake. LRP6 is a unique member of this family for its function as a co-receptor for Wnt signal transduction. The work in our laboratory has shown that LRP6 also plays a key role in lipoprotein and TG clearance, glucose homoeostasis, and atherosclerosis. The role of these receptor proteins in pathogenesis of diverse metabolic risk factors is emerging, rendering them targets of novel therapeutics for metabolic syndrome and atherosclerosis. This manuscript reviews the physiological role of the LDLR family of proteins and describes its involvement in pathogenesis of hyperlipidemia and atherosclerosis.
Atherosclerosis and the Lectin-like OXidized low-density lipoprotein scavenger receptor.
Vohra Ravinder S,Murphy Jane E,Walker John H,Ponnambalam Sreenivasan,Homer-Vanniasinkam Shervanthi
Trends in cardiovascular medicine
The Lectin-like OXidized low-density lipoprotein scavenger receptor (LOX-1) is implicated in vascular inflammation and atherosclerotic plaque initiation, progression, and destabilization. LOX-1 levels are elevated upon recognition of oxidized low-density lipoprotein, a key pro-atherogenic substance in the vasculature. Recent evidence indicates this gene product is a biomarker of inflammation and disease status. We review and assess the role of LOX-1 in atherosclerotic plaque formation, physiologic regulation, and as a biomarker and target in cardiovascular disease diagnosis and prevention.
10.1016/j.tcm.2005.12.001
The lectin-like oxidized low-density lipoprotein receptor-1 and its soluble form: cardiovascular implications.
Navarra Teresa,Del Turco Serena,Berti Sergio,Basta Giuseppina
Journal of atherosclerosis and thrombosis
The lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) is a multiligand receptor, whose repertoire of ligands includes oxidized low-density lipoprotein, advanced glycation endproducts, platelets, neutrophils, apoptotic/aged cells and bacteria. Sustained expression of LOX-1 by critical target cells, including endothelial cells, smooth muscle cells and macrophages in proximity to these ligands, sets the stage for chronic cellular activation and tissue damage suggesting the interaction of cellular LOX-1 with its ligands to contribute to the formation and development of atherosclerotic plaques. Studies with transgenic and knockout mouse models have elucidated in part the role of LOX-1 in the pathogenesis of atherosclerosis and cardiac remodeling. Recently, a circulating soluble form of LOX-1 (sLOX-1), corresponding solely to its extracellular domain, has been identified in human serum. Circulating levels of sLOX-1 are increased in inflammatory and atherosclerotic conditions and are associated with acute coronary syndrome, with the severity of coronary artery disease, and with serum biomarkers for oxidative stress and inflammation, suggesting that they could be a useful marker for vascular injury. However, many interesting questions have not yet been answered and in this review, we provide an updated overview of the literature on this receptor and on likely future directions.
10.5551/jat.3228
The role of electronegative low-density lipoprotein in cardiovascular diseases and its therapeutic implications.
Akyol Sumeyya,Lu Jonathan,Akyol Omer,Akcay Fatih,Armutcu Ferah,Ke Liang-Yin,Chen Chu-Huang
Trends in cardiovascular medicine
Cardiovascular disease (CVD) is a health problem of great concern to both the public and medical authorities. Low-density lipoprotein (LDL) has been reported to play an important role in both the development and progression of CVD, but studies are underway to determine how LDL exerts its effects. In recent years, it has been found that LDL has several subfractions, each of which affects endothelial function differently; L5, the most electronegative fraction, has been shown to be unique in that it induces an atherogenic response. This review examines the current knowledge concerning the relationships between L5 and CVD and highlights the role of L5 in the pathophysiology of CVD, especially with regards to atherosclerosis.
10.1016/j.tcm.2016.11.002
Low-density lipoprotein receptor-related protein 6-mediated signaling pathways and associated cardiovascular diseases: diagnostic and therapeutic opportunities.
Kang Sheng
Human genetics
Low-density lipoprotein receptor-related protein 6 (LRP6) is a member of the low-density lipoprotein receptors (LDLRs) family and accumulating evidence points to the critical role of LRP6 in cardiovascular health and homeostasis. In addition to presenting the well-appreciated roles in canonical signaling regulating blood pressure, blood glucose, lipid metabolism, atherosclerosis, cardiac valve disease, cardiac development, Alzheimer's disease and tumorigenesis, LRP6 also inhibits non-canonical Wnt signals that promote arterial smooth muscle cell proliferation and vascular calcification. Noticeably, the role of LRP6 is displayed in cardiometabolic disease, an increasingly important clinical burden with aging and obesity. The prospect for cardiovascular diseases treatment via targeting LRP6-mediated signaling pathways may improve central blood pressure and lipid metabolism, and reduce neointima formation and myocardial ischemia-reperfusion injury. Thus, a deep and comprehensive understanding of LRP6 structure, function and signaling pathways will contribute to clinical diagnosis, therapy and new drug development for LRP6-related cardiovascular diseases.
10.1007/s00439-020-02124-8
Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1): a crucial driver of atherosclerotic cardiovascular disease.
European heart journal
Cardiovascular diseases (CVDs), specifically lipid-driven atherosclerotic CVDs, remain the number one cause of death worldwide. The lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1), a scavenger receptor that promotes endothelial dysfunction by inducing pro-atherogenic signalling and plaque formation via the endothelial uptake of oxidized LDL (oxLDL) and electronegative LDL, contributes to the initiation, progression, and destabilization of atheromatous plaques, eventually leading to the development of myocardial infarction and certain forms of stroke. In addition to its expression in endothelial cells, LOX-1 is expressed in macrophages, cardiomyocytes, fibroblasts, dendritic cells, lymphocytes, and neutrophils, further implicating this receptor in multiple aspects of atherosclerotic plaque formation. LOX-1 holds promise as a novel diagnostic and therapeutic target for certain CVDs; therefore, understanding the molecular structure and function of LOX-1 is of critical importance. In this review, we highlight the latest scientific findings related to LOX-1, its ligands, and their roles in the broad spectrum of CVDs. We describe recent findings from basic research, delineate their translational value, and discuss the potential of LOX-1 as a novel target for the prevention, diagnosis, and treatment of related CVDs.
10.1093/eurheartj/ehaa770
Apolipoprotein E in lipoprotein metabolism, health and cardiovascular disease.
Marais A David
Pathology
Apolipoprotein E (apoE), a 34 kDa circulating glycoprotein of 299 amino acids, predominantly synthesised in the liver, associates with triglyceride-rich lipoproteins to mediate the clearance of their remnants after enzymatic lipolysis in the circulation. Its synthesis in macrophages initiates the formation of high density-like lipoproteins to effect reverse cholesterol transport to the liver. In the nervous system apoE forms similar lipoproteins which perform the function of distributing lipids amongst cells. ApoE accounts for much of the variation in plasma lipoproteins by three common variants (isoforms) that influence low-density lipoprotein concentration and the risk of atherosclerosis. ApoE2 generally is most favourable and apoE4 least favourable for cardiovascular and neurological health. The apoE variants relate to different amino acids at positions 112 and 158: cysteine in both for apoE2, arginine at both sites for apoE4, and respectively cysteine and arginine for apoE3 that is viewed as the wild type. Paradoxically, under metabolic stress, homozygosity for apoE2 may result in dysbetalipoproteinaemia in adults owing to impaired binding of remnant lipoproteins to the LDL receptor and related proteins as well as heparan sulphate proteoglycans. This highly atherogenic condition is also seen with other mutations in apoE, but with autosomal dominant inheritance. Mutations in apoE may also cause lipoprotein glomerulopathy. In the central nervous system apoE binds amyloid β-protein and tau protein and fragments may incur cellular damage. ApoE4 is a strong risk factor for the development of Alzheimer's disease. ApoE has several other physiological effects that may influence health and disease, including supply of docosahexaenoic acid for the brain and modulating immune and inflammatory responses. Genotyping of apoE may have application in disorders of lipoprotein metabolism as well as glomerulopathy and may be relevant to personalised medicine in understanding cardiovascular risk, and the outcome of nutritional and therapeutic interventions. Quantitation of apoE will probably not be clinically useful. ApoE is also of interest as it may generate peptides with biological function and could be employed in nanoparticles that may allow crossing of the blood-brain barrier. Therapeutic options may emerge from these newer insights.
10.1016/j.pathol.2018.11.002
PCSK9 Inhibition: From Current Advances to Evolving Future.
Cells
Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secretory serine protease synthesized primarily by the liver. It mainly promotes the degradation of low-density lipoprotein receptor (LDL-R) by binding LDL-R, reducing low-density lipoprotein cholesterol (LDL-C) clearance. In addition to regulating LDL-R, PCSK9 inhibitors can also bind Toll-like receptors (TLRs), scavenger receptor B (SR-B/CD36), low-density lipoprotein receptor-related protein 1 (LRP1), apolipoprotein E receptor-2 (ApoER2) and very-low-density lipoprotein receptor (VLDL-R) reducing the lipoprotein concentration and slowing thrombosis. In addition to cardiovascular diseases, PCSK9 is also used in pancreatic cancer, sepsis, and Parkinson's disease. Currently marketed PCSK9 inhibitors include alirocumab, evolocumab, and inclisiran, as well as small molecules, nucleic acid drugs, and vaccines under development. This review systematically summarized the application, preclinical studies, safety, mechanism of action, and latest research progress of PCSK9 inhibitors, aiming to provide ideas for the drug research and development and the clinical application of PCSK9 in cardiovascular diseases and expand its application in other diseases.
10.3390/cells11192972
Lipoprotein receptor signalling in atherosclerosis.
Mineo Chieko
Cardiovascular research
The founding member of the lipoprotein receptor family, low-density lipoprotein receptor (LDLR) plays a major role in the atherogenesis through the receptor-mediated endocytosis of LDL particles and regulation of cholesterol homeostasis. Since the discovery of the LDLR, many other structurally and functionally related receptors have been identified, which include low-density lipoprotein receptor-related protein (LRP)1, LRP5, LRP6, very low-density lipoprotein receptor, and apolipoprotein E receptor 2. The scavenger receptor family members, on the other hand, constitute a family of pattern recognition proteins that are structurally diverse and recognize a wide array of ligands, including oxidized LDL. Among these are cluster of differentiation 36, scavenger receptor class B type I and lectin-like oxidized low-density lipoprotein receptor-1. In addition to the initially assigned role as a mediator of the uptake of macromolecules into the cell, a large number of studies in cultured cells and in in vivo animal models have revealed that these lipoprotein receptors participate in signal transduction to modulate cellular functions. This review highlights the signalling pathways by which these receptors influence the process of atherosclerosis development, focusing on their roles in the vascular cells, such as macrophages, endothelial cells, smooth muscle cells, and platelets. Human genetics of the receptors is also discussed to further provide the relevance to cardiovascular disease risks in humans. Further knowledge of the vascular biology of the lipoprotein receptors and their ligands will potentially enhance our ability to harness the mechanism to develop novel prophylactic and therapeutic strategies against cardiovascular diseases.
10.1093/cvr/cvz338
Low density lipoprotein receptor endocytosis in cardiovascular disease and the factors affecting LDL levels.
Progress in molecular biology and translational science
Cardiovascular disease (CVD) is the one of major global health issues with approximately 30% of the mortality reported in the mid-income population. Low-density lipoprotein (LDL) plays a crucial role in development of CVD. High LDL along with others forms a plaque and blocks arteries, resulting in CVD. The present chapter deals with the mechanism of receptor-mediated endocytosis of LDL and its management by drugs such as statins and PCSK9 inhibitors along with dietary supplementation for health improvements.
10.1016/bs.pmbts.2022.09.010