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Bhale AS, Meilhac O, d'Hellencourt CL, Vijayalakshmi MA, Venkataraman K. Cholesterol transport and beyond: Illuminating the versatile functions of HDL apolipoproteins through structural insights and functional implications. Biofactors 2024. [PMID: 38661230 DOI: 10.1002/biof.2057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 04/02/2024] [Indexed: 04/26/2024]
Abstract
High-density lipoproteins (HDLs) play a vital role in lipid metabolism and cardiovascular health, as they are intricately involved in cholesterol transport and inflammation modulation. The proteome of HDL particles is indeed complex and distinct from other components in the bloodstream. Proteomics studies have identified nearly 285 different proteins associated with HDL; however, this review focuses more on the 15 or so traditionally named "apo" lipoproteins. Important lipid metabolizing enzymes closely working with the apolipoproteins are also discussed. Apolipoproteins stand out for their integral role in HDL stability, structure, function, and metabolism. The unique structure and functions of each apolipoprotein influence important processes such as inflammation regulation and lipid metabolism. These interactions also shape the stability and performance of HDL particles. HDLs apolipoproteins have multifaceted roles beyond cardiovascular diseases (CVDs) and are involved in various physiological processes and disease states. Therefore, a detailed exploration of these apolipoproteins can offer valuable insights into potential diagnostic markers and therapeutic targets. This comprehensive review article aims to provide an in-depth understanding of HDL apolipoproteins, highlighting their distinct structures, functions, and contributions to various physiological processes. Exploiting this knowledge holds great potential for improving HDL function, enhancing cholesterol efflux, and modulating inflammatory processes, ultimately benefiting individuals by limiting the risks associated with CVDs and other inflammation-based pathologies. Understanding the nature of all 15 apolipoproteins expands our knowledge of HDL metabolism, sheds light on their pathological implications, and paves the way for advancements in the diagnosis, prevention, and treatment of lipid and inflammatory-related disorders.
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Affiliation(s)
- Aishwarya Sudam Bhale
- Centre for Bio-Separation Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, India
| | - Olivier Meilhac
- Inserm, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), Université de La Réunion, Saint-Pierre, France
| | - Christian Lefebvre d'Hellencourt
- Inserm, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), Université de La Réunion, Saint-Pierre, France
| | | | - Krishnan Venkataraman
- Centre for Bio-Separation Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, India
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Alves M, Laranjeira F, Correia-da-Silva G. Understanding Hypertriglyceridemia: Integrating Genetic Insights. Genes (Basel) 2024; 15:190. [PMID: 38397180 PMCID: PMC10887881 DOI: 10.3390/genes15020190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/25/2024] Open
Abstract
Hypertriglyceridemia is an exceptionally complex metabolic disorder characterized by elevated plasma triglycerides associated with an increased risk of acute pancreatitis and cardiovascular diseases such as coronary artery disease. Its phenotype expression is widely heterogeneous and heavily influenced by conditions as obesity, alcohol consumption, or metabolic syndromes. Looking into the genetic underpinnings of hypertriglyceridemia, this review focuses on the genetic variants in LPL, APOA5, APOC2, GPIHBP1 and LMF1 triglyceride-regulating genes reportedly associated with abnormal genetic transcription and the translation of proteins participating in triglyceride-rich lipoprotein metabolism. Hypertriglyceridemia resulting from such genetic abnormalities can be categorized as monogenic or polygenic. Monogenic hypertriglyceridemia, also known as familial chylomicronemia syndrome, is caused by homozygous or compound heterozygous pathogenic variants in the five canonical genes. Polygenic hypertriglyceridemia, also known as multifactorial chylomicronemia syndrome in extreme cases of hypertriglyceridemia, is caused by heterozygous pathogenic genetic variants with variable penetrance affecting the canonical genes, and a set of common non-pathogenic genetic variants (polymorphisms, using the former nomenclature) with well-established association with elevated triglyceride levels. We further address recent progress in triglyceride-lowering treatments. Understanding the genetic basis of hypertriglyceridemia opens new translational opportunities in the scope of genetic screening and the development of novel therapies.
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Affiliation(s)
- Mara Alves
- Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal;
| | - Francisco Laranjeira
- CGM—Centro de Genética Médica Jacinto de Magalhães, Centro Hospitalar Universitário de Santo António (CHUdSA), 4099-028 Porto, Portugal;
- UMIB—Unit for Multidisciplinary Research in Biomedicine, ICBAS—School of Medicine and Biomedical Sciences, University of Porto, 4050-346 Porto, Portugal
- ITR—Laboratory for Integrative and Translational Research in Population Health, 4050-600 Porto, Portugal
| | - Georgina Correia-da-Silva
- UCIBIO Applied Molecular Biosciences Unit and Associate Laboratory i4HB—Institute for Health and Bioeconomy Laboratory of Biochemistry, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal
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3
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Deng H, Li J, Shah AA, Ge L, Ouyang W. Comprehensive in-silico analysis of deleterious SNPs in APOC2 and APOA5 and their differential expression in cancer and cardiovascular diseases conditions. Genomics 2023; 115:110567. [PMID: 36690263 DOI: 10.1016/j.ygeno.2023.110567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 01/04/2023] [Accepted: 01/19/2023] [Indexed: 01/22/2023]
Abstract
Genetic variations in APOC2 and APOA5 genes involve activating lipoprotein lipase (LPL), responsible for the hydrolysis of triglycerides (TG) in blood and whose impaired functions affect the TG metabolism and are associated with metabolic diseases. In this study, we investigate the biological significance of genetic variations at the DNA sequence and structural level using various computational tools. Subsequently, 8 (APOC2) and 17 (APOA5) non-synonymous SNPs (nsSNPs) were identified as high-confidence deleterious SNPs based on the effects of the mutations on protein conservation, stability, and solvent accessibility. Furthermore, based on our docking results, the interaction of native and mutant forms of the corresponding proteins with LPL depicts differences in root mean square deviation (RMSD), and binding affinities suggest that these mutations may affect their function. Furthermore, in vivo, and in vitro studies have shown that differential expression of these genes in disease conditions due to the influence of nsSNPs abundance may be associated with promoting the development of cancer and cardiovascular diseases. Preliminary screening using computational methods can be a helpful start in understanding the effects of mutations in APOC2 and APOA5 on lipid metabolism; however, further wet-lab experiments would further strengthen the conclusions drawn from the computational study.
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Affiliation(s)
- Huiyin Deng
- Department of Anesthesiology, the Third Xiangya Hospital, Central South University, Changsha, Hunan Province 410013, PR China
| | - Jiuyi Li
- Department of Anesthesiology, the First People's Hospital of Chenzhou, Chenzhou, Hunan Province 410013, PR China
| | - Abid Ali Shah
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan Province 410013, PR China
| | - Lite Ge
- Department of Neurology, Second Xiangya Hospital, Central South University, Changsha, Hunan Province 410013, PR China; The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan Province 410013, PR China; Hunan provincial key laboratory of Neurorestoratology, the Second Affiliated Hospital, Hunan Normal University, Hunan Province 410013, PR China.
| | - Wen Ouyang
- Department of Anesthesiology, the Third Xiangya Hospital, Central South University, Changsha, Hunan Province 410013, PR China.
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Wen Y, Chen YQ, Konrad RJ. The Regulation of Triacylglycerol Metabolism and Lipoprotein Lipase Activity. Adv Biol (Weinh) 2022; 6:e2200093. [PMID: 35676229 DOI: 10.1002/adbi.202200093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/03/2022] [Indexed: 01/28/2023]
Abstract
Triacylglycerol (TG) metabolism is tightly regulated to maintain a pool of TG within circulating lipoproteins that can be hydrolyzed in a tissue-specific manner by lipoprotein lipase (LPL) to enable the delivery of fatty acids to adipose or oxidative tissues as needed. Elevated serum TG concentrations, which result from a deficiency of LPL activity or, more commonly, an imbalance in the regulation of tissue-specific LPL activities, have been associated with an increased risk of atherosclerotic cardiovascular disease through multiple studies. Among the most critical LPL regulators are the angiopoietin-like (ANGPTL) proteins ANGPTL3, ANGPTL4, and ANGPTL8, and a number of different apolipoproteins including apolipoprotein A5 (ApoA5), apolipoprotein C2 (ApoC2), and apolipoprotein C3 (ApoC3). These ANGPTLs and apolipoproteins work together to orchestrate LPL activity and therefore play pivotal roles in TG partitioning, hydrolysis, and utilization. This review summarizes the mechanisms of action, epidemiological findings, and genetic data most relevant to these ANGPTLs and apolipoproteins. The interplay between these important regulators of TG metabolism in both fasted and fed states is highlighted with a holistic view toward understanding key concepts and interactions. Strategies for developing safe and effective therapeutics to reduce circulating TG by selectively targeting these ANGPTLs and apolipoproteins are also discussed.
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Affiliation(s)
- Yi Wen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA
| | - Yan Q Chen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA
| | - Robert J Konrad
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA
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5
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Jacob J, Boczkowska S, Zaluska W, Buraczynska M. Apolipoprotein A5 gene polymorphism (rs662799) and cardiovascular disease in end-stage kidney disease patients. BMC Nephrol 2022; 23:307. [PMID: 36071387 PMCID: PMC9450442 DOI: 10.1186/s12882-022-02925-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 08/22/2022] [Indexed: 11/29/2022] Open
Abstract
Background Plasma triglyceride (TG) levels are a significant risk factor for cardiovascular disease (CVD). The APOA5 gene is one of the crucial factors in plasma TG metabolism regulation. The rs662799 polymorphism in the APOA5 gene has been reported to be associated with cardiovascular disease. The goal of this study was to evaluate the potential association of this variant with CVD in patients with end-stage kidney disease. Methods In this case–control study the polymorphism was analyzed using the PCR–RFLP method in 800 consecutive patients with ESKD and 500 healthy controls. The genotype and allele distribution was compared between subgroups of patients with CVD (552) versus those without CVD (248). Results The frequency of the minor allele (C) in the healthy individuals was 9% compared to 12% in ESRD group (p = 0.09). The difference between groups was slightly higher for CC homozygote (3.5% versus 1.6%, p = 0.042). The ESKD patient group was analyzed according to the presence or absence of CVD. The significant differences in the polymorphism distribution were revealed in this analysis. The frequency of the C allele in the CVD + subgroup was 14% compared to 6% in CVD- patients (p = 0.001). In the CVD + subgroup the ORs (95% CI) for the C allele and CC genotype were 2.41 (1.61–3.6), p < 0.001 and 3.13 (1.07–9.14), p = 0.036, respectively. This indicates to the association of the variant C allele with cardiovascular disease in ESKD patients. The CC homozygotes have a threefold higher odds of CVD compared to TT homozygotes. The highest frequency of the C allele (18%) was observed in subgroup of patients with diabetic nephropathy, with OR (95% CI) 3.40 (2.13–5.43), p < 0.001.The presence of minor allele (CC and CT genotypes) was significantly associated with increased plasma triglyceride levels (p < 0.001 for both CVD + and CVD- groups). Conclusion The present study demonstrated the effect of rs662799 polymorphism on plasma TG levels and its association with the development of cardiovascular disease in ESKD patients.
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Affiliation(s)
- Jerry Jacob
- Hope Medical Institute, Newport News, VA, USA
| | - Sylwia Boczkowska
- Department of Nephrology, Medical University of Lublin, Jaczewskiego 8, 20-950, Lublin, Poland
| | - Wojciech Zaluska
- Department of Nephrology, Medical University of Lublin, Jaczewskiego 8, 20-950, Lublin, Poland
| | - Monika Buraczynska
- Department of Nephrology, Medical University of Lublin, Jaczewskiego 8, 20-950, Lublin, Poland.
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Zhang BH, Yin F, Qiao YN, Guo SD. Triglyceride and Triglyceride-Rich Lipoproteins in Atherosclerosis. Front Mol Biosci 2022; 9:909151. [PMID: 35693558 PMCID: PMC9174947 DOI: 10.3389/fmolb.2022.909151] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/06/2022] [Indexed: 12/11/2022] Open
Abstract
Cardiovascular disease (CVD) is still the leading cause of death globally, and atherosclerosis is the main pathological basis of CVDs. Low-density lipoprotein cholesterol (LDL-C) is a strong causal factor of atherosclerosis. However, the first-line lipid-lowering drugs, statins, only reduce approximately 30% of the CVD risk. Of note, atherosclerotic CVD (ASCVD) cannot be eliminated in a great number of patients even their LDL-C levels meet the recommended clinical goals. Previously, whether the elevated plasma level of triglyceride is causally associated with ASCVD has been controversial. Recent genetic and epidemiological studies have demonstrated that triglyceride and triglyceride-rich lipoprotein (TGRL) are the main causal risk factors of the residual ASCVD. TGRLs and their metabolites can promote atherosclerosis via modulating inflammation, oxidative stress, and formation of foam cells. In this article, we will make a short review of TG and TGRL metabolism, display evidence of association between TG and ASCVD, summarize the atherogenic factors of TGRLs and their metabolites, and discuss the current findings and advances in TG-lowering therapies. This review provides information useful for the researchers in the field of CVD as well as for pharmacologists and clinicians.
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Affiliation(s)
| | | | - Ya-Nan Qiao
- Institute of Lipid Metabolism and Atherosclerosis, Innovative Drug Research Centre, School of Pharmacy, Weifang Medical University, Weifang, China
| | - Shou-Dong Guo
- Institute of Lipid Metabolism and Atherosclerosis, Innovative Drug Research Centre, School of Pharmacy, Weifang Medical University, Weifang, China
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7
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Apolipoprotein A-V is a potential target for treating coronary artery disease: evidence from genetic and metabolomic analyses. J Lipid Res 2022; 63:100193. [PMID: 35278410 PMCID: PMC9062431 DOI: 10.1016/j.jlr.2022.100193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 02/14/2022] [Accepted: 02/28/2022] [Indexed: 11/22/2022] Open
Abstract
Triglyceride (TG)-lowering LPL variants in combination with genetic LDL-C-lowering variants are associated with reduced risk of coronary artery disease (CAD). Genetic variation in the APOA5 gene encoding apolipoprotein A-V also strongly affects TG levels, but the potential clinical impact and underlying mechanisms are yet to be resolved. Here, we aimed to study the effects of APOA5 genetic variation on CAD risk and plasma lipoproteins through factorial genetic association analyses. Using data from 309,780 European-ancestry participants from the UK Biobank, we evaluated the effects of lower TG levels as a result of genetic variation in APOA5 and/or LPL on CAD risk with or without a background of reduced LDL-C. Next, we compared lower TG levels via APOA5 and LPL variation with over 100 lipoprotein measurements in a combined sample from the Netherlands Epidemiology of Obesity study (N = 4,838) and the Oxford Biobank (N = 6,999). We found that lower TG levels due to combined APOA5 and LPL variation and genetically-influenced lower LDL-C levels afforded the largest reduction in CAD risk (odds ratio: 0.78 (0.73-0.82)). Compared to patients with genetically-influenced lower TG via LPL, genetically-influenced lower TG via APOA5 had similar and independent, but notably larger, effects on the lipoprotein profile. Our results suggest that lower TG levels as a result of APOA5 variation have strong beneficial effects on CAD risk and the lipoprotein profile, which suggest apo A-V may be a potential novel therapeutic target for CAD prevention.
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8
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Balasubramaniam D, Schroeder O, Russell AM, Fitchett JR, Austin AK, Beyer TP, Chen YQ, Day JW, Ehsani M, Heng AR, Zhen EY, Davies J, Glaesner W, Jones BE, Siegel RW, Qian YW, Konrad RJ. An anti-ANGPTL3/8 antibody decreases circulating triglycerides by binding to a LPL-inhibitory leucine zipper-like motif. J Lipid Res 2022; 63:100198. [PMID: 35307397 PMCID: PMC9036128 DOI: 10.1016/j.jlr.2022.100198] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 02/24/2022] [Accepted: 03/11/2022] [Indexed: 12/20/2022] Open
Abstract
Triglycerides (TG) are required for fatty acid transport and storage and are essential for human health. Angiopoietin-like-protein 8 (ANGPTL8) has previously been shown to form a complex with ANGPTL3 that increases circulating TG by potently inhibiting LPL. We also recently showed that the TG-lowering apolipoprotein A5 (ApoA5) decreases TG levels by suppressing ANGPTL3/8-mediated LPL inhibition. To understand how LPL binds ANGPTL3/8 and ApoA5 blocks this interaction, we used hydrogen-deuterium exchange mass-spectrometry and molecular modeling to map binding sites of LPL and ApoA5 on ANGPTL3/8. Remarkably, we found that LPL and ApoA5 both bound a unique ANGPTL3/8 epitope consisting of N-terminal regions of ANGPTL3 and ANGPTL8 that are unmasked upon formation of the ANGPTL3/8 complex. We further used ANGPTL3/8 as an immunogen to develop an antibody targeting this same epitope. After refocusing on antibodies that bound ANGPTL3/8, as opposed to ANGPTL3 or ANGPTL8 alone, we utilized bio-layer interferometry to select an antibody exhibiting high-affinity binding to the desired epitope. We revealed an ANGPTL3/8 leucine zipper-like motif within the anti-ANGPTL3/8 epitope, the LPL-inhibitory region, and the ApoA5-interacting region, suggesting the mechanism by which ApoA5 lowers TG is via competition with LPL for the same ANGPTL3/8-binding site. Supporting this hypothesis, we demonstrate that the anti-ANGPTL3/8 antibody potently blocked ANGPTL3/8-mediated LPL inhibition in vitro and dramatically lowered TG levels in vivo. Together, these data show that an anti-ANGPTL3/8 antibody targeting the same leucine zipper-containing epitope recognized by LPL and ApoA5 markedly decreases TG by suppressing ANGPTL3/8-mediated LPL inhibition.
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Affiliation(s)
| | - Oliver Schroeder
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Anna M Russell
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | | | - Aaron K Austin
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Thomas P Beyer
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Yan Q Chen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Jonathan W Day
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Mariam Ehsani
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Aik Roy Heng
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Eugene Y Zhen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Julian Davies
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Wolfgang Glaesner
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Bryan E Jones
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Robert W Siegel
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Yue-Wei Qian
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Robert J Konrad
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA.
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Abstract
Triglyceride-rich lipoproteins deliver fatty acids to tissues for oxidation and for storage. Release of fatty acids from circulating lipoprotein triglycerides is carried out by lipoprotein lipase (LPL), thus LPL serves as a critical gatekeeper of fatty acid uptake into tissues. LPL activity is regulated by a number of extracellular proteins including three members of the angiopoietin-like family of proteins. In this review, we discuss our current understanding of how, where, and when ANGPTL3, ANGPTL4, and ANGPTL8 regulate lipoprotein lipase activity, with a particular emphasis on how these proteins interact with each other to coordinate triglyceride metabolism and fat partitioning.
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Affiliation(s)
- Kelli L Sylvers-Davie
- Department of Biochemistry, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa, Iowa City, Iowa
| | - Brandon S J Davies
- Department of Biochemistry, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa, Iowa City, Iowa
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10
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The Importance of Lipoprotein Lipase Regulation in Atherosclerosis. Biomedicines 2021; 9:biomedicines9070782. [PMID: 34356847 PMCID: PMC8301479 DOI: 10.3390/biomedicines9070782] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/02/2021] [Accepted: 07/04/2021] [Indexed: 02/07/2023] Open
Abstract
Lipoprotein lipase (LPL) plays a major role in the lipid homeostasis mainly by mediating the intravascular lipolysis of triglyceride rich lipoproteins. Impaired LPL activity leads to the accumulation of chylomicrons and very low-density lipoproteins (VLDL) in plasma, resulting in hypertriglyceridemia. While low-density lipoprotein cholesterol (LDL-C) is recognized as a primary risk factor for atherosclerosis, hypertriglyceridemia has been shown to be an independent risk factor for cardiovascular disease (CVD) and a residual risk factor in atherosclerosis development. In this review, we focus on the lipolysis machinery and discuss the potential role of triglycerides, remnant particles, and lipolysis mediators in the onset and progression of atherosclerotic cardiovascular disease (ASCVD). This review details a number of important factors involved in the maturation and transportation of LPL to the capillaries, where the triglycerides are hydrolyzed, generating remnant lipoproteins. Moreover, LPL and other factors involved in intravascular lipolysis are also reported to impact the clearance of remnant lipoproteins from plasma and promote lipoprotein retention in capillaries. Apolipoproteins (Apo) and angiopoietin-like proteins (ANGPTLs) play a crucial role in regulating LPL activity and recent insights into LPL regulation may elucidate new pharmacological means to address the challenge of hypertriglyceridemia in atherosclerosis development.
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11
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Kersten S. Long-lost friend is back in the game. J Lipid Res 2021; 62:100072. [PMID: 33812921 PMCID: PMC8091049 DOI: 10.1016/j.jlr.2021.100072] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 03/20/2021] [Indexed: 11/18/2022] Open
Affiliation(s)
- Sander Kersten
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Wageningen, The Netherlands.
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12
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Chen YQ, Pottanat TG, Zhen EY, Siegel RW, Ehsani M, Qian YW, Konrad RJ. ApoA5 lowers triglyceride levels via suppression of ANGPTL3/8-mediated LPL inhibition. J Lipid Res 2021; 62:100068. [PMID: 33762177 PMCID: PMC8079461 DOI: 10.1016/j.jlr.2021.100068] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 03/07/2021] [Indexed: 02/06/2023] Open
Abstract
Triglyceride (TG) molecules represent the major storage form of fatty acids, and TG metabolism is essential to human health. However, the mechanistic details surrounding TG metabolism are complex and incompletely elucidated. Although it is known that angiopoietin-like protein 8 (ANGPTL8) increases TGs through an ANGPTL3/8 complex that inhibits LPL, the mechanism governing ApoA5, which lowers TGs, has remained elusive. Current hypotheses for how ApoA5 acts include direct stimulation of LPL, facilitation of TG-containing particle uptake, and regulation of hepatic TG secretion. Using immunoprecipitation-MS and Western blotting, biolayer interferometry, functional LPL enzymatic assays, and kinetic analyses of LPL activity, we show that ApoA5 associates with ANGPTL3/8 in human serum and most likely decreases TG by suppressing ANGPTL3/8-mediated LPL inhibition. We also demonstrate that ApoA5 has no direct effect on LPL, nor does it suppress the LPL-inhibitory activities of ANGPTL3, ANGPTL4, or ANGPTL4/8. Importantly, ApoA5 suppression of ANGPTL3/8-mediated LPL inhibition occurred at a molar ratio consistent with the circulating concentrations of ApoA5 and ANGPTL3/8. Because liver X receptor (LXR) agonists decrease ApoA5 expression and cause hypertriglyceridemia, we investigated the effect of the prototypical LXR agonist T0901317 on human primary hepatocytes. We observed that T0901317 modestly stimulated hepatocyte ApoA5 release, but markedly stimulated ANGPTL3/8 secretion. Interestingly, the addition of insulin to T0901317 attenuated ApoA5 secretion, but further increased ANGPTL3/8 secretion. Together, these results reveal a novel intersection of ApoA5 and ANGPTL3/8 in the regulation of TG metabolism and provide a possible explanation for LXR agonist-induced hypertriglyceridemia.
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Affiliation(s)
- Yan Q Chen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Thomas G Pottanat
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA; Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Eugene Y Zhen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Robert W Siegel
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Mariam Ehsani
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Yue-Wei Qian
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Robert J Konrad
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA.
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13
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Wu SA, Kersten S, Qi L. Lipoprotein Lipase and Its Regulators: An Unfolding Story. Trends Endocrinol Metab 2021; 32:48-61. [PMID: 33277156 PMCID: PMC8627828 DOI: 10.1016/j.tem.2020.11.005] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 02/07/2023]
Abstract
Lipoprotein lipase (LPL) is one of the most important factors in systemic lipid partitioning and metabolism. It mediates intravascular hydrolysis of triglycerides packed in lipoproteins such as chylomicrons and very-low-density lipoprotein (VLDL). Since its initial discovery in the 1940s, its biology and pathophysiological significance have been well characterized. Nonetheless, several studies in the past decade, with recent delineation of LPL crystal structure and the discovery of several new regulators such as angiopoietin-like proteins (ANGPTLs), glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1), lipase maturation factor 1 (LMF1) and Sel-1 suppressor of Lin-12-like 1 (SEL1L), have completely transformed our understanding of LPL biology.
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Affiliation(s)
- Shuangcheng Alivia Wu
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI48105, USA.
| | - Sander Kersten
- Nutrition Metabolism and Genomics group, Wageningen University, Wageningen, The Netherlands
| | - Ling Qi
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI48105, USA; Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48105, USA.
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Morjane I, Charoute H, Ouatou S, Elkhattabi L, Benrahma H, Saile R, Rouba H, Barakat A. Association of c.56C > G (rs3135506) Apolipoprotein A5 Gene Polymorphism with Coronary Artery Disease in Moroccan Subjects: A Case-Control Study and an Updated Meta-Analysis. Cardiol Res Pract 2020; 2020:5981971. [PMID: 32832146 PMCID: PMC7424381 DOI: 10.1155/2020/5981971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 02/29/2020] [Accepted: 03/03/2020] [Indexed: 11/18/2022] Open
Abstract
PURPOSE Coronary artery diseases (CAD) are clinical cardiovascular events associated with dyslipidemia in common. The interaction between environmental and genetic factors can be responsible for CAD. The present paper aimed to examine the association between c.56C > G (rs3135506) APOA5 gene polymorphism and CAD in Moroccan individuals and to perform an association update meta-analysis. MATERIALS AND METHODS The c.56C > G variant was genotyped in 122 patients with CAD and 134 unrelated controls. Genetic association analysis and comparison of biochemical parameters were performed using R statistical language. In addition, a comprehensive meta-analysis including eleven published studies in addition to our case-control study results was conducted using Review Manager 5.3. Publication bias was examined by Egger's test and funnel plot. RESULTS The case-control study data showed that the c.56C > G polymorphism was associated with CAD susceptibility under codominant (P-value = 0.001), recessive (P-value <0.001) and log-additive (P-value = 0.008) inheritance models. In addition, this polymorphism was significantly associated with increased levels of systolic and diastolic blood pressures, triglycerides, glycemia, and total cholesterol. Furthermore, meta-analysis showed a significant association between the c.56C > G gene polymorphism and increased risk of CAD under recessive (OR = 3.39[1.77-6.50], P value <0.001) and homozygote codominant (OR = 3.96[2.44-6.45], P value <0.001) models. CONCLUSION Our case-control study revealed a significant association between c.56C > G polymorphism and CAD in the Moroccan population. In addition, meta-analysis data supported the implication of this polymorphism in CAD susceptibility.
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Affiliation(s)
- Imane Morjane
- Laboratory of Genomics and Human Genetics, Institut Pasteur Du Maroc, Casablanca, Morocco
- Laboratory of Biology and Health, Faculty of Sciences Ben M'Sik, Hassan II University of Casablanca, Casablanca, Morocco
| | - Hicham Charoute
- Laboratory of Genomics and Human Genetics, Institut Pasteur Du Maroc, Casablanca, Morocco
| | - Sanaa Ouatou
- Laboratory of Genomics and Human Genetics, Institut Pasteur Du Maroc, Casablanca, Morocco
| | - Lamiae Elkhattabi
- Laboratory of Genomics and Human Genetics, Institut Pasteur Du Maroc, Casablanca, Morocco
- Laboratory of Biology and Health, Faculty of Sciences Ben M'Sik, Hassan II University of Casablanca, Casablanca, Morocco
| | - Houda Benrahma
- Laboratory of Genomics and Human Genetics, Institut Pasteur Du Maroc, Casablanca, Morocco
- National Reference Laboratory (LNR), Faculty of Medicine, Mohammed VI University of Health Sciences (UM6SS), Casablanca, Morocco
| | - Rachid Saile
- Laboratory of Biology and Health, Faculty of Sciences Ben M'Sik, Hassan II University of Casablanca, Casablanca, Morocco
| | - Hassan Rouba
- Laboratory of Genomics and Human Genetics, Institut Pasteur Du Maroc, Casablanca, Morocco
| | - Abdelhamid Barakat
- Laboratory of Genomics and Human Genetics, Institut Pasteur Du Maroc, Casablanca, Morocco
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Kim HK, Anwar MA, Choi S. Association of BUD13-ZNF259-APOA5-APOA1-SIK3 cluster polymorphism in 11q23.3 and structure of APOA5 with increased plasma triglyceride levels in a Korean population. Sci Rep 2019; 9:8296. [PMID: 31165758 PMCID: PMC6549162 DOI: 10.1038/s41598-019-44699-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 05/22/2019] [Indexed: 12/24/2022] Open
Abstract
In this association study on chromosome 11, the data from 12,537 Korean individuals within the Health Examinee (HEXA) and the Korea Association Resource (KARE) projects were analysed to identify genetic loci correlating with increased and decreased plasma triglyceride (TG) levels. We identified a locus in chromosomal region 11q23.3 that harbours genes BUD13, ZNF259, APOA5, APOA1, and SIK3, which may be associated with plasma TG levels. In this locus, 13 relevant single-nucleotide polymorphisms (SNPs) were found: rs184616707, rs118175510, rs60954647, rs79408961, and rs180373 (near BUD13); rs11604424 (in ZNF259); rs2075291, rs651821, and rs7123666 (in or near APOA5); rs525028 (near APOA1), and rs645258, rs10160754, and rs142395187 (in or near SIK3). All 13 SNPs satisfied the genome-wide significance level (P < 5.0 × 10-8) in both meta-analysis and conditional analysis. Haplotype analysis of six SNPs (rs79408961, rs180373, rs2075291, rs651821, rs525028, and rs10160754) that were selected based on the β coefficient and conditional P values, revealed nine common haplotypes (with frequency 0.02-0.34) associated with both increased and reduced TG levels. Furthermore, to shed light on possible structural implications, we modelled and simulated the G185C variant of APOA5 (corresponding to rs2075291), which showed the strongest association. Molecular dynamics simulation results showed that this polymorphic variant of APOA5 has a different hydrogen bond network, increased average distance between chains, and an ability to form distinct clusters. Owing to the orientation of cysteine, the possibility of disulphide bond formation with other proteins is evident. In summary, our association and modelling analyses provided evidence that genetic variations in chromosomal region 11q23.3 are associated with elevated TG levels.
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Affiliation(s)
- Han-Kyul Kim
- Department of Molecular Science and Technology, Ajou University, Suwon, 16499, Korea
| | - Muhammad Ayaz Anwar
- Department of Molecular Science and Technology, Ajou University, Suwon, 16499, Korea
| | - Sangdun Choi
- Department of Molecular Science and Technology, Ajou University, Suwon, 16499, Korea.
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Function of different proportions of apolipoprotein A-I cysteine mutants and apolipoprotein A-V on recombinant high-density lipoproteins in vitro. Biosci Rep 2019; 39:BSR20190547. [PMID: 31023964 PMCID: PMC6522722 DOI: 10.1042/bsr20190547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/10/2019] [Accepted: 04/23/2019] [Indexed: 11/17/2022] Open
Abstract
To explore the anti-atherosclerotic effects of recombinant high-density lipoproteins (rHDL) of apolipoprotein AI wild-type (apoA-Iwt), apolipoprotein AI Milano (apoA-IM), apolipoprotein AI (N74C) (apoA-I (N74C) )and apolipoprotein AV (apoA-V). We constructed rHDL liposomes (rHDLs), which included apoA-Iwt, apoA-IM, and apoA-I (N74C), followed by the synthesis of rHDLs, with the indicated ratios of apoA-Iwt, apoA-IM, apoA-I (N74C) and apoA-V. We investigated the anti-atherosclerotic effects by experiments including the DMPC clearance assay and experiments that assessed the in vitro antioxidation against low-density lipoprotein, the cellular uptake of oxidized low-density lipoprotein (oxLDL) and the in vitro intracellular lipid accumulation. Electron microscopy results revealed that as more apoA-V was present in rHDLs, the particle size of rHDLs was larger. The DMPC clearance assay subsequently showed that rHDL protein mixtures could promote DMPC turbidity clearance when more apoA-V was included in the reaction mixtures, with apoAV-rHDL showing the strongest turbidity clearance ability (P<0.05 vs AI-rHDL). In vitro antioxidation against low-density lipoprotein assays indicated that rHDLs containing apoA-V had increasing oxidation resistance against low-density lipoprotein (LDL) with higher apoA-V contents. Finally, cellular uptake of oxLDL and intracellular lipids suggested an apparent oxidation resistance to LDL oxidation in vitro and a reduced intracellular lipid accumulation in THP-1-derived macrophages, with AIM-rHDL demonstrating the greatest ability to decrease intracellular lipid accumulation. Different proportions of apolipoprotein A-I cysteine mutants and apolipoprotein A-V of rHDL changed the lipid binding capacity, particle size, and antioxidant capacity. These changes may show a beneficial effect of rHDL on atherosclerosis.
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San Mauro Martín I, Sanz Rojo S, Garicano Vilar E, Collado Yurrita L, Blumenfeld Olivares JA. Modulation of plasma triglycerides concentration by sterol-based treatment in children carrying different genes. Ann Pediatr Cardiol 2019; 12:83-89. [PMID: 31143031 PMCID: PMC6521671 DOI: 10.4103/apc.apc_86_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Dyslipidemias have increased during the last decades in children. AIM The objective of this study was to analyze the influence of different polymorphisms in plasma triglyceride levels of children following a dietary treatment with plant sterols. DESIGN A randomized, double-blind, crossover, controlled clinical trial was carried out in 26 children (16 women). MATERIALS AND METHODS Commercial milk, with 2.24 g sterols, was ingested daily during 3 weeks , and the same amount of kimmed milk without sterols, during the 3 week placebo phase. Both phases were separated by a washout period of 2 weeks. At the beginning and end of each phase, blood draws were performed. RESULTS Apolipoprotein A5 Ser19Trp (P = 0.002), peroxisome proliferator-activated receptor-alpha L162V (P = 0.003), APOE APOE2/3/4 (P = 0.012), and APOE APOE2,3,4 (P = 0.025) show statistically significant differences between their haplotypes in plasma triglyceride levels. Other genes did not show statistically significant differences. CONCLUSIONS Further studies are needed to establish which genotype combinations would be the most protective against hypertriglyceridemia.
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Hsu LC, Hsu LS, Lee TH. Association of apolipoprotein A1 and A5 polymorphisms with stroke subtypes in Han Chinese people in Taiwan. Gene 2019; 684:76-81. [PMID: 30367981 DOI: 10.1016/j.gene.2018.10.050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 10/12/2018] [Accepted: 10/19/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND PURPOSES Stroke is a leading cause of death and serious disability worldwide. Now, evidences indicate that dyslipidemia may play an important role in stroke. APOA1 and APOA5 involve in lipid metabolism. In this study, we investigated the association of APOA1 rs670 and APOA5 rs662799 with different stroke subtypes in the Han Chinese population of Taiwan. METHODS A total of 1751 participants, including 459 control subjects, 606 large artery atherosclerosis (LAA), 339 small vessel occlusion (SVO), and 347 hypertensive intracranial hemorrhage (HICH), were enrolled. The presence of rs670 and rs662799 was analyzed through polymerase chain react ion and matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry. RESULTS Notably, the frequency of the rs662799 C allele was significantly lower in the SVO patients than in the controls (24.36% vs. 29.74%, P = 0.024). The frequencies of heterozygote TC [odd ratio (OR) = 0.732, 95% confidence interval (CI) = 0.544-0.984, P = 0.038] and TC + CC (OR = 0.719, 95% CI = 0.542-0.953, P = 0.022) genotypes were significantly lower in the SVO patients than in the controls. In addition, triglyceride levels in individuals carrying the rs662799 TC + CC genotype were significantly higher than in those carrying the TT genotype, especially in older age, female, and body mass index (BMI) ≥ 25 groups. On the contrary, the low-density lipoprotein-cholesterol (LDL-C) was significantly lower in rs662799 TC + CC genotype than TT genotype. The BMI was significantly lower in subjects with rs662799 TC + CC genotype than those with TT genotype, especially in older age and female. High-density lipoprotein-cholesterol (HDL-C) levels were higher in individuals carrying the rs670 GG genotype than in those carrying the AG + AA genotype, especially in BMI < 25 group. Logistic regression analysis showed that the rs662799 C allele (TC + CC) was an independent protective factor for SVO after adjustment for conventional risk factors (OR = 0.709, 95% CI = 0.526-0.956; P = 0.024). CONCLUSION GG genotype of rs670 is correlated with high serum HDL-C levels, whereas TC + CC genotype of rs662799 is associated with high serum triglyceride and low LDL and BMI levels. In addition, the rs662799 C allele (TC + CC) is an independent protective factor for SVO in the Han Chinese population in Taiwan.
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Affiliation(s)
- Li-Chi Hsu
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan; National Yang-Ming University school of Medicine, Taipei, Taiwan
| | - Li-Sung Hsu
- Institutes of Biochemistry, Microbiology, and Immunology, Chung Shan Medical University, Taichung, Taiwan; Clinical Laboratory, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Tsong-Hai Lee
- College of Medicine, Chang Gung University, Taoyuan, Taiwan; Stroke Center and Department of Neurology, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan.
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Su X, Kong Y, Peng DQ. New insights into apolipoprotein A5 in controlling lipoprotein metabolism in obesity and the metabolic syndrome patients. Lipids Health Dis 2018; 17:174. [PMID: 30053818 PMCID: PMC6064078 DOI: 10.1186/s12944-018-0833-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Accepted: 07/20/2018] [Indexed: 01/01/2023] Open
Abstract
Apolipoprotein A5 (apoA5) has been identified to play an important role in lipid metabolism, specifically in triglyceride (TG) and TG-rich lipoproteins (TRLs) metabolism. Numerous evidence has demonstrated for an association between apoA5 and the increased risk of obesity and metabolic syndrome, but the mechanism remains to be fully elucidated. Recently, several studies verified that apoA5 could significantly reduce plasma TG level by stimulating lipoprotein lipase (LPL) activity, and the intracellular role of apoA5 has also been proved since apoA5 is associated with cytoplasmic lipid droplets (LDs) and affects intrahepatic TG accumulation. Furthermore, since adipocytes provide the largest storage depot for TG and play a crucial role in the development of obesity, we could infer that apoA5 also acts as a novel regulator to modulate TG storage in adipocytes. In this review, we focus on the association of gene and protein of apoA5 with obesity and metabolic syndrome, and provide new insights into the physiological role of apoA5 in humans, giving a potential therapeutic target for obesity and associated disorders.
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Affiliation(s)
- Xin Su
- Department of Cardiovascular Medicine, the Second Xiangya Hospital, Central South University, Changsha, 410011, Hunan, China
| | - Yi Kong
- Department of Dermatology, Hunan Key Laboratory of Medical Epigenomics, the Second Xiangya Hospital, Central South University, Changsha, 410011, Hunan, China
| | - Dao-Quan Peng
- Department of Cardiovascular Medicine, the Second Xiangya Hospital, Central South University, Changsha, 410011, Hunan, China.
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Luo J, Xu L, Li J, Zhao S. Effects and mechanisms of apolipoprotein A-V on the regulation of lipid accumulation in cardiomyocytes. Lipids Health Dis 2018. [PMID: 29530023 PMCID: PMC5848552 DOI: 10.1186/s12944-018-0692-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background Apolipoprotein (apo) A-V is a key regulator of triglyceride (TG) metabolism. We investigated effects of apoA-V on lipid metabolism in cardiomyocytes in this study. Methods We first examined whether apoA-V can be taken up by cardiomyocytes and whether low density lipoprotein receptor family members participate in this process. Next, triglyceride (TG) content and lipid droplet changes were detected at different concentrations of apoA-V in normal and lipid-accumulation cells in normal and obese animals. Finally, we tested the levels of fatty acids (FAs) taken up into cardiomyocytes and lipid secretion through [14C]-oleic acid. Results Our results show that heart tissue has apoA-V protein, and apoA-V is taken up by cardiomyocytes. When HL-1 cells were transfected with low density lipoprotein receptor (LDLR)-related protein 1(LRP1) siRNA, apoA-V intake decreased by 53% (P<0.05), while a 37% lipid accumulation in HL-1 cells remain unchanged. ApoA-V localized to the cytoplasm and was associated with lipid droplets in HL-1 cells. A 1200 and 1800 ng/mL apoA-V intervention decreased TG content by 28% and 45% in HL-1 cells, respectively and decreased TG content by 39% in mouse heart tissue (P<0.05). However, apoA-V had no effects on TG content in either normal HL-1 cells or mice. The levels of FAs taken up into cardiomyocytes decreased by 43% (P < 0.05), and the levels of TG and cholesterol ester secretion increased by 1.2-fold and 1.6-fold, respectively (P < 0.05). Conclusion ApoA-V is a novel regulator of lipid metabolism in cardiomyocytes.
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Affiliation(s)
- Jun Luo
- Department of Cardiology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China
| | - Li Xu
- Department of The Second Chest Medicine, The Affiliated Cancer Hospital of Xiangya School of medicine, Central South University, Changsha, Hunan, 410013, China
| | - Jiang Li
- Department of Cardiology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China.
| | - Shuiping Zhao
- Department of Cardiology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China.
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Bertoccini L, Sentinelli F, Incani M, Bailetti D, Cimini FA, Barchetta I, Cavallo MG, Cossu E, Lenzi A, Loche S, Baroni MG. The Arg282Ser missense mutation in APOA5 gene determines a reduction of triglyceride and LDL-cholesterol in children, together with low serum levels of apolipoprotein A-V. Lipids Health Dis 2017; 16:179. [PMID: 28927406 PMCID: PMC5606109 DOI: 10.1186/s12944-017-0569-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Accepted: 09/13/2017] [Indexed: 11/23/2022] Open
Abstract
Background Apolipoprotein A-V (ApoA-V) is a recognized regulator of plasma triglycerides (TGs), and previous studies have shown associations between variants in APOA5 (apolipoprotein-A5) gene and high TG levels. Recently, a new association between the Arg282Ser missense mutation (rs778114184 G > T) in APOA5 gene and decreased triglyceride levels has been shown in an adult population from Sardinia. In this study we add further insight into the role of APOA5 by exploring whether this association begins early in life in children, or becomes manifest only in adulthood. We performed the genetic association analysis of APOA5 in a cohort of 925 overweight and obese children and adolescents from Sardinia, Italy, to see if the genetic burden is already at play before modifying risk factors are interacting. Results We identified 24 heterozygous subjects for the Arg282Ser variant and no homozygous subject. Here we show that the Arg282Ser mutation in APOA5 gene is associated with a significant reduction of TG (−15.5 mg/dl), total (−18.1 mg/dl) and LDL-cholesterol (−14.8 mg/dl) levels in overweight/obese children and adolescents, indicating that indeed this association appears early in life. Also, we observed a significant reduction in serum apoA-V levels in heterozygous children. Conclusions Our data clearly show that the Arg282Ser mutation in APOA5 gene determines a reduction of TG, total and LDL-cholesterol and apolipoprotein A-V levels in overweight/obese children and adolescents, demonstrating that this mutation has the power to affect lipid levels already since childhood.
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Affiliation(s)
- Laura Bertoccini
- Department of Experimental Medicine, Sapienza University of Rome, Policlinico Umberto I, 00161, Rome, Italy
| | - Federica Sentinelli
- Department of Experimental Medicine, Sapienza University of Rome, Policlinico Umberto I, 00161, Rome, Italy
| | - Michela Incani
- Endocrinology and Diabetes, Department of Medical Sciences, University of Cagliari, Cagliari, Italy
| | - Diego Bailetti
- Department of Experimental Medicine, Sapienza University of Rome, Policlinico Umberto I, 00161, Rome, Italy
| | - Flavia Agata Cimini
- Department of Experimental Medicine, Sapienza University of Rome, Policlinico Umberto I, 00161, Rome, Italy
| | - Ilaria Barchetta
- Department of Experimental Medicine, Sapienza University of Rome, Policlinico Umberto I, 00161, Rome, Italy
| | - Maria Gisella Cavallo
- Department of Experimental Medicine, Sapienza University of Rome, Policlinico Umberto I, 00161, Rome, Italy
| | - Efisio Cossu
- Endocrinology and Diabetes, Department of Medical Sciences, University of Cagliari, Cagliari, Italy
| | - Andrea Lenzi
- Department of Experimental Medicine, Sapienza University of Rome, Policlinico Umberto I, 00161, Rome, Italy
| | - Sandro Loche
- Pediatric Endocrine Unit, Regional Hospital for Microcitemia, Cagliari, Italy
| | - Marco Giorgio Baroni
- Department of Experimental Medicine, Sapienza University of Rome, Policlinico Umberto I, 00161, Rome, Italy. .,Neuromed, Pozzilli, IS, Italy.
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Lee J, Hegele RA. Investigated treatments for lipoprotein lipase deficiency and related metabolic disorders. Expert Opin Orphan Drugs 2017. [DOI: 10.1080/21678707.2017.1311784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Shahid SU, Shabana NA, Cooper JA, Rehman A, Humphries SE. Common variants in the genes of triglyceride and HDL-C metabolism lack association with coronary artery disease in the Pakistani subjects. Lipids Health Dis 2017; 16:24. [PMID: 28143480 PMCID: PMC5282842 DOI: 10.1186/s12944-017-0419-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Accepted: 01/20/2017] [Indexed: 11/16/2022] Open
Abstract
Background Serum Triglyceride (TG) and High Density Lipoprotein (HDL-C) levels are modifiable coronary artery disease (CAD) risk factors. Polymorphisms in the genes regulating TG and HDL-C levels contribute to the development of CAD. The objective of the current study was to investigate the effect of four such single nucleotide polymorphism (SNPs) in the genes for Lipoprotein Lipase (LPL) (rs328, rs1801177), Apolipoprotein A5 (APOA5) (rs66279) and Cholesteryl ester transfer protein (CETP) (rs708272) on HDL-C and TG levels and to examine the association of these SNPs with CAD risk. Methods A total of 640 subjects (415 cases, 225 controls) were enrolled in the study. The SNPs were genotyped by KASPar allelic discrimination technique. Serum HDL-C and TG were determined by spectrophotometric methods. Results The population under study was in Hardy Weinberg equilibrium and minor allele of SNP rs1801177 was completely absent in the studied subjects. The SNPs were association with TG and HDL-C levels was checked through regression analysis. For rs328, the effect size of each risk allele on TG and HDL-C (mmol/l) was 0.16(0.08) and −0.11(0.05) respectively. Similarly, the effect size of rs662799 for TG and HDL-C was 0.12(0.06) and −0.13(0.0.3) and that of rs708272 was 0.08(0.04) and 0.1(0.03) respectively. The risk allele frequencies of the SNPs were higher in cases than controls, but the difference was not significant (p > 0.05) and SNPs were not associated with CAD risk (p > 0.05). The combined gene score of four SNPs significantly raised TG and lowered HDL-C but did not increase CAD risk. Conclusion The studied SNPs were associated with TG and HDL-C levels, but not with CAD in Pakistani population under study. Electronic supplementary material The online version of this article (doi:10.1186/s12944-017-0419-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Saleem Ullah Shahid
- Department of Microbiology and Molecular Genetics, University of the Punjab, Lahore, Pakistan, 54590.
| | - N A Shabana
- Department of Microbiology and Molecular Genetics, University of the Punjab, Lahore, Pakistan, 54590
| | - Jackie A Cooper
- Centre of Cardiovascular Genetics, British Heart Foundation Laboratories, University College London, London, WC1E6JF, UK, England
| | - Abdul Rehman
- Department of Microbiology and Molecular Genetics, University of the Punjab, Lahore, Pakistan, 54590
| | - Steve E Humphries
- Centre of Cardiovascular Genetics, British Heart Foundation Laboratories, University College London, London, WC1E6JF, UK, England
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Heidker RM, Caiozzi GC, Ricketts ML. Grape Seed Procyanidins and Cholestyramine Differentially Alter Bile Acid and Cholesterol Homeostatic Gene Expression in Mouse Intestine and Liver. PLoS One 2016; 11:e0154305. [PMID: 27111442 PMCID: PMC4844140 DOI: 10.1371/journal.pone.0154305] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 04/12/2016] [Indexed: 01/05/2023] Open
Abstract
Bile acid (BA) sequestrants, lipid-lowering agents, may be prescribed as a monotherapy or combination therapy to reduce the risk of coronary artery disease. Over 33% of adults in the United States use complementary and alternative medicine strategies, and we recently reported that grape seed procyanidin extract (GSPE) reduces enterohepatic BA recirculation as a means to reduce serum triglyceride (TG) levels. The current study was therefore designed to assess the effects on BA, cholesterol and TG homeostatic gene expression following co-administration with GSPE and the BA sequestrant, cholestyramine (CHY). Eight-week old male C57BL/6 mice were treated for 4 weeks with either a control or 2% CHY-supplemented diet, after which, they were administered vehicle or GSPE for 14 hours. Liver and intestines were harvested and gene expression was analyzed. BA, cholesterol, non-esterified fatty acid and TG levels were also analyzed in serum and feces. Results reveal that GSPE treatment alone, and co-administration with CHY, regulates BA, cholesterol and TG metabolism differently than CHY administration alone. Notably, GSPE decreased intestinal apical sodium-dependent bile acid transporter (Asbt) gene expression, while CHY significantly induced expression. Administration with GSPE or CHY robustly induced hepatic BA biosynthetic gene expression, especially cholesterol 7α-hydroxylase (Cyp7a1), compared to control, while co-administration further enhanced expression. Treatment with CHY induced both intestinal and hepatic cholesterologenic gene expression, while co-administration with GSPE attenuated the CHY-induced increase in the liver but not intestine. CHY also induced hepatic lipogenic gene expression, which was attenuated by co-administration with GSPE. Consequently, a 25% decrease in serum TG levels was observed in the CHY+GSPE group, compared to the CHY group. Collectively, this study presents novel evidence demonstrating that GSPE provides additive and complementary efficacy as a lipid-lowering combination therapy in conjunction with CHY by attenuating hepatic cholesterol synthesis, enhancing BA biosynthesis and decreasing lipogenesis, which warrants further investigation.
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Affiliation(s)
- Rebecca M. Heidker
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, Nevada, United States of America
| | - Gianella C. Caiozzi
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, Nevada, United States of America
| | - Marie-Louise Ricketts
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada Reno, Reno, Nevada, United States of America
- * E-mail:
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Abstract
Apolipoprotein A5 (apoA5) is a potent regulator of triglyceride (TG) metabolism and therefore may contribute to the pathogenesis of non-alcoholic fatty liver disease (NAFLD), a disease characterised by excessive TG-rich lipid droplets in hepatocytes. To test this hypothesis, we examined the mRNA expression of apoA5 in paediatric NAFLD livers in comparison to healthy controls. According to microarray and quantitative real-time PCR, human NAFLD livers exhibited elevated apoA5 expression compared to healthy controls. The apoA5 expression levels were positively correlated with hepatic TG storage and a marker for lipid droplets (perilipin), but were not correlated with plasma TG levels. These observations were confirmed with a NAFLD rat model. Interestingly, apoA5 expression was not altered in cultured fat-laden HepG2 cells, demonstrating that fat storage does not induce apoA5 in NAFLD livers. Therefore, the correlation between apoA5 and intracellular fat storage is likely explained by the potent effect of apoA5 in promoting intracellular fat storage. Our NAFLD patients and rats had elevated insulin resistance, which may have a role in elevating apoA5 expression in NAFLD livers. Our data support the hypothesis that apoA5 promotes hepatic TG storage and therefore contributes to the pathogenesis of NAFLD, and may represent a potential target for therapeutic intervention.
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Kim YR, Hong SH. Association of Apolipoprotein A5 Gene Polymorphisms with Metabolic Syndrome in the Korean Population. Genet Test Mol Biomarkers 2016; 20:130-6. [PMID: 26760709 DOI: 10.1089/gtmb.2015.0250] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
AIMS Functional defects of the ApoA5 protein have been identified as risk factors for hypertriglyceridemia, vascular diseases and susceptibility to metabolic syndrome (MetS). These associations are neither strong nor consistent in all populations studied. In this study, we investigated the association between the ApoA5 -1131T>C and -12,238T>C polymorphic loci in Korean patients with MetS. METHODS A total of 1074 subjects, including 415 patients with MetS and 659 healthy control subjects, were enrolled to investigate the affect of ApoA5 polymorphisms on risk of MetS. Genotyping of the ApoA5 polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism techniques. RESULTS The CC genotype and the dominant (TT vs. TC+CC) and recessive (TT+TC vs. CC) models of the -1131T>C polymorphism were associated with increased MetS susceptibility (p < 0.001, p = 0.018, and p = 0.002, respectively). The association was male-specific when stratified by gender. With regard to the -12,238T>C polymorphism, the TC and CC genotypes and the dominant (TT vs. TC+CC) and recessive (TT+TC vs. CC) models were frequently found in the patient group, compared with the control group (p = 0.001, p < 0.001, p < 0.001, and p = 0.031, respectively). The T-C, C-T, and C-C haplotypes of the ApoA5 -1131T>C and -12,238T>C polymorphisms were associated with an increased risk for MetS (p < 0.001, p = 0.001, and p < 0.001, respectively). The variant of the ApoA5 -1131T>C polymorphism was also associated with increased triglyceride (TG) levels. Dominant models of ApoA5 -1131T>C and -12,238T>C polymorphisms were associated with the risk components of MetS by the stratification analysis. CONCLUSION The -1131C and -12,238C variants and the C-containing haplotypes of ApoA5 -1131T>C and -12,238T>C polymorphisms were associated with higher risk for MetS in the Korean population. The -1131C variant was also associated with the increased level of TG.
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Affiliation(s)
- Young Ree Kim
- 1 Department of Laboratory Medicine, School of Medicine, Jeju National University , Jeju, Republic of Korea
| | - Seung-Ho Hong
- 2 Department of Science Education, Teachers College, Jeju National University , Jeju, Republic of Korea
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Kayama K, Okada T, Fuwa K, Nagano N, Hosono S, Takahashi S, Takahashi S. Apolipoprotein A-V concentration in preterm infants. J Clin Lipidol 2015; 9:647-51. [DOI: 10.1016/j.jacl.2015.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 05/30/2015] [Accepted: 06/05/2015] [Indexed: 10/23/2022]
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Dose apolipoprotein AV has influence on the regulation of fatty acids and triglyceride metabolism in cardiomyocyte in case of obesity. Int J Cardiol 2015; 185:109-11. [PMID: 25791104 DOI: 10.1016/j.ijcard.2015.03.119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/07/2015] [Indexed: 11/23/2022]
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Zhang LS, Xu M, Yang Q, Ryan RO, Howles P, Tso P. Apolipoprotein A-V deficiency enhances chylomicron production in lymph fistula mice. Am J Physiol Gastrointest Liver Physiol 2015; 308:G634-42. [PMID: 25617349 PMCID: PMC4385892 DOI: 10.1152/ajpgi.00339.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 01/16/2015] [Indexed: 01/31/2023]
Abstract
Apolipoprotein A-V (apoA-V), a liver-synthesized apolipoprotein discovered in 2001, strongly modulates fasting plasma triglycerides (TG). Little is reported on the effect of apoA-V on postprandial plasma TG, an independent predictor for atherosclerosis. Overexpressing apoA-V in mice suppresses postprandial TG, but mechanisms focus on increased lipolysis or clearance of remnant particles. Unknown is whether apoA-V suppresses the absorption of dietary lipids by the gut. This study examines how apoA-V deficiency affects the steady-state absorption and lymphatic transport of dietary lipids in chow-fed mice. Using apoA-V knockout (KO, n = 8) and wild-type (WT, n = 8) lymph fistula mice, we analyzed the uptake and lymphatic transport of lipids during a continuous infusion of an emulsion containing [(3)H]triolein and [(14)C]cholesterol. ApoA-V KO mice showed a twofold increase in (3)H (P < 0.001) and a threefold increase in (14)C (P < 0.001) transport into the lymph compared with WT. The increased lymphatic transport was accompanied by a twofold reduction (P < 0.05) in mucosal (3)H, suggesting that apoA-V KO mice more rapidly secreted [(3)H]TG out of the mucosa into the lymph. ApoA-V KO mice also produced chylomicrons more rapidly than WT (P < 0.05), as measured by the transit time of [(14)C]oleic acid from the intestinal lumen to lymph. Interestingly, apoA-V KO mice produced a steadily increasing number of chylomicron particles over time, as measured by lymphatic apoB output. The data suggest that apoA-V suppresses the production of chylomicrons, playing a previously unknown role in lipid metabolism that may contribute to the postprandial hypertriglyceridemia associated with apoA-V deficiency.
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Affiliation(s)
- Linda S. Zhang
- 1Children's Hospital Oakland Research Institute, Oakland, California
| | - Min Xu
- 1Children's Hospital Oakland Research Institute, Oakland, California
| | - Qing Yang
- 1Children's Hospital Oakland Research Institute, Oakland, California
| | - Robert O. Ryan
- 2Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio; and
| | - Philip Howles
- 1Children's Hospital Oakland Research Institute, Oakland, California
| | - Patrick Tso
- 1Children's Hospital Oakland Research Institute, Oakland, California
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Camporez JPG, Kanda S, Petersen MC, Jornayvaz FR, Samuel VT, Bhanot S, Petersen KF, Jurczak MJ, Shulman GI. ApoA5 knockdown improves whole-body insulin sensitivity in high-fat-fed mice by reducing ectopic lipid content. J Lipid Res 2014; 56:526-536. [PMID: 25548259 PMCID: PMC4340301 DOI: 10.1194/jlr.m054080] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
ApoA5 has a critical role in the regulation of plasma TG concentrations. In order to determine whether ApoA5 also impacts ectopic lipid deposition in liver and skeletal muscle, as well as tissue insulin sensitivity, we treated mice with an antisense oligonucleotide (ASO) to decrease hepatic expression of ApoA5. ASO treatment reduced ApoA5 protein expression in liver by 60–70%. ApoA5 ASO-treated mice displayed approximately 3-fold higher plasma TG concentrations, which were associated with decreased plasma TG clearance. Furthermore, ApoA5 ASO-treated mice fed a high-fat diet (HFD) exhibited reduced liver and skeletal muscle TG uptake and reduced liver and muscle TG and diacylglycerol (DAG) content. HFD-fed ApoA5 ASO-treated mice were protected from HFD-induced insulin resistance, as assessed by hyperinsulinemic-euglycemic clamps. This protection could be attributed to increases in both hepatic and peripheral insulin responsiveness associated with decreased DAG activation of protein kinase C (PKC)-ε and PKCθ in liver and muscle, respectively, and increased insulin-stimulated AKT2 phosphorylation in these tissues. In summary, these studies demonstrate a novel role for ApoA5 as a modulator of susceptibility to diet-induced liver and muscle insulin resistance through regulation of ectopic lipid accumulation in liver and skeletal muscle.
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Affiliation(s)
| | - Shoichi Kanda
- Departments of Internal Medicine Yale University School of Medicine, New Haven, CT
| | - Max C Petersen
- Departments of Internal Medicine Yale University School of Medicine, New Haven, CT; Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT
| | - François R Jornayvaz
- Departments of Internal Medicine Yale University School of Medicine, New Haven, CT
| | - Varman T Samuel
- Departments of Internal Medicine Yale University School of Medicine, New Haven, CT
| | | | - Kitt Falk Petersen
- Departments of Internal Medicine Yale University School of Medicine, New Haven, CT
| | - Michael J Jurczak
- Departments of Internal Medicine Yale University School of Medicine, New Haven, CT
| | - Gerald I Shulman
- Departments of Internal Medicine Yale University School of Medicine, New Haven, CT; Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT; Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT.
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32
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Shou W, Wang Y, Xie F, Wang B, Yang L, Wu H, Wang Y, Wang Z, Shi J, Huang W. A functional polymorphism affecting the APOA5 gene expression is causally associated with plasma triglyceride levels conferring coronary atherosclerosis risk in Han Chinese Population. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2147-54. [DOI: 10.1016/j.bbadis.2014.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 07/29/2014] [Accepted: 08/13/2014] [Indexed: 01/21/2023]
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Li S, Hu B, Wang Y, Wu D, Jin L, Wang X. Influences of APOA5 variants on plasma triglyceride levels in Uyghur population. PLoS One 2014; 9:e110258. [PMID: 25313938 PMCID: PMC4196964 DOI: 10.1371/journal.pone.0110258] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 09/11/2014] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Single nucleotide polymorphisms (SNPs) in apolipoprotein A5 (APOA5) gene are associated with triglyceride (TG) levels. However, the minor allele frequencies and linkage disequilibriums (LDs) of the SNPs in addition to their effects on TG levels vary greatly between Caucasians and East Asians. The distributions of the SNPs/haplotypes and their associations with TG levels in Uyghur population, an admixture population of Caucasians and East Asians, have not been reported to date. Here, we performed a cross-sectional study to address these. METHODS Genotyping of four SNPs in APOA5 (rs662799, rs3135506, rs2075291, and rs2266788) was performed in 1174 unrelated Uyghur subjects. SNP/haplotype and TG association analyses were conducted. RESULTS The frequencies of the SNPs in Uyghurs were in between those in Caucasians and East Asians. The LD between rs662799 and rs2266788 in Uyghurs was stronger than that in East Asians but weaker than that in Caucasians, and the four SNPs resulted in four haplotypes (TGGT, CGGC, TCGT, and CGTT arranged in the order of rs662799, rs3135506, rs2075291, and rs2266788) representing 99.2% of the population. All the four SNPs were significantly associated with TG levels. Compared with non-carriers, carriers of rs662799-C, rs3135506-C, rs2075291-T, and rs2266788-C alleles had 16.0%, 15.1%, 17.1%, and 12.4% higher TG levels, respectively. When haplotype TGGT was defined as the reference, the haplotypes CGGC, TCGT, and CGTT resulted in 16.1%, 19.0%, and 19.8% higher TG levels, respectively. The proportions of variance in TG explained by APOA5 locus were 2.5%, 0.3%, 0.4%, and 1.9% for single SNP rs662799, rs3135506, rs2075291, and rs2266788, respectively, and 3.0% for the haplotypes constructed by them. CONCLUSIONS The association profiles between the SNPs and haplotypes at APOA5 locus and TG levels in this admixture population differed from those in Caucasians and East Asians. The functions of these SNPs and haplotypes need to be elucidated comprehensively.
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Affiliation(s)
- Shuyuan Li
- Ministry of Education Key Laboratory of Contemporary Anthropology and State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China; Fudan-Taizhou Institute of Health Sciences, Taizhou, Jiangsu, China
| | - Bin Hu
- Ministry of Education Key Laboratory of Contemporary Anthropology and State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China; Fudan-Taizhou Institute of Health Sciences, Taizhou, Jiangsu, China
| | - Yi Wang
- Ministry of Education Key Laboratory of Contemporary Anthropology and State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China; Fudan-Taizhou Institute of Health Sciences, Taizhou, Jiangsu, China
| | - Di Wu
- Ministry of Education Key Laboratory of Contemporary Anthropology and State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Li Jin
- Ministry of Education Key Laboratory of Contemporary Anthropology and State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China; Fudan-Taizhou Institute of Health Sciences, Taizhou, Jiangsu, China
| | - Xiaofeng Wang
- Ministry of Education Key Laboratory of Contemporary Anthropology and State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China; Fudan-Taizhou Institute of Health Sciences, Taizhou, Jiangsu, China
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Apolipoprotein A-V level may contribute to the development of obesity-associated dyslipidemia. Obes Res Clin Pract 2014; 7:e415-9. [PMID: 24304484 DOI: 10.1016/j.orcp.2012.08.192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 07/31/2012] [Accepted: 08/11/2012] [Indexed: 11/20/2022]
Abstract
AIM In a mice study, insulin suppressed apolipoprotein A-V (apoA-V) gene expression in a dose dependent manner. Thus, we investigated the association between apoA-V levels and dyslipidemias in obese children with hyperinsulinemia. METHODS The subjects were 17 obese children (15 male, 2 female) aged 11.8 ± 2.4 years. Total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), triglyceride (TG), apoA-V and insulin levels were determined. RESULTS Obese children with hyperinsulinemia had greater percent overweight, higher TG level, lower HDLC level and lower apoA-V level than those without hyperinsulinemia. In simple regression analysis, apoA-V level correlated negatively with TG (r = -0.613, p = 0.0152) and insulin levels (r = -0.566, p = 0.0279), and positively correlated with HDLC (r = 0.811, p = 0.0002). In stepwise regression analysis, insulin level emerged as the independent determinant of TG level after apoA-V level was taken into account, whereas apoA-V emerged as the independent determinant of HDLC level after adjusting for insulin level. CONCLUSIONS Insulin may be a potent regulator of serum apoA-V level in obesity, and apoA-V level may partly contribute to the development of obesity-associated dyslipidemia.
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Amerindian-specific regions under positive selection harbour new lipid variants in Latinos. Nat Commun 2014; 5:3983. [PMID: 24886709 PMCID: PMC4062071 DOI: 10.1038/ncomms4983] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 04/29/2014] [Indexed: 12/13/2022] Open
Abstract
Dyslipidemia and obesity are especially prevalent in populations with Amerindian
backgrounds, such as Mexican–Americans, which predispose these populations to
cardiovascular disease. Here we design an approach, known as the cross-population allele
screen (CPAS), which we conduct prior to a genome-wide association study (GWAS) in 19,273
Europeans and Mexicans, in order to identify Amerindian risk genes in Mexicans. Utilizing
CPAS to restrict the GWAS input variants to only those differing in frequency between the
two populations, we identify novel Amerindian lipid genes, receptor-related orphan receptor alpha (RORA) and salt-inducible kinase
3 (SIK3), and three
loci previously unassociated with dyslipidemia or obesity. We also detect lipoprotein lipase (LPL) and apolipoprotein
A5 (APOA5)
harbouring specific Amerindian signatures of risk variants and haplotypes. Notably, we
observe that SIK3 and one novel
lipid locus underwent positive selection in Mexicans. Furthermore, after a high-fat meal,
the SIK3 risk variant carriers
display high triglyceride levels. These findings suggest that Amerindian-specific genetic
architecture leads to a higher incidence of dyslipidemia and obesity in modern Mexicans. Dyslipidemia and obesity have a high prevalence in populations with
Amerindian backgrounds, such as Mexican–Americans. Here, the authors design an approach
to identify Amerindian risk genes in Mexicans and identify five genomic loci, which include
RORA and SIK3 that may contribute to the risk of dyslipidemia and obesity in
Amerindian populations.
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36
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Wu CL, Zhao SP, Yu BL. Intracellular role of exchangeable apolipoproteins in energy homeostasis, obesity and non-alcoholic fatty liver disease. Biol Rev Camb Philos Soc 2014; 90:367-76. [PMID: 24834836 DOI: 10.1111/brv.12116] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 04/10/2014] [Accepted: 04/17/2014] [Indexed: 02/06/2023]
Affiliation(s)
- Chen-Lu Wu
- Department of Cardiology; The Second Xiangya Hospital, Central South University; Changsha Hunan 410011 China
| | - Shui-Ping Zhao
- Department of Cardiology; The Second Xiangya Hospital, Central South University; Changsha Hunan 410011 China
| | - Bi-Lian Yu
- Department of Cardiology; The Second Xiangya Hospital, Central South University; Changsha Hunan 410011 China
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Abstract
Despite the critical importance of plasma lipoproteins in the development of atherosclerosis, varying degrees of evidence surround the causal associations of lipoproteins with coronary artery disease (CAD). These causal contributions can be assessed by employing genetic variants as unbiased proxies for lipid levels. A relatively large number of low-density lipoprotein cholesterol (LDL-C) variants strongly associate with CAD, confirming the causal impact of this lipoprotein on atherosclerosis. Although not as firmly established, genetic evidence supporting a causal role of triglycerides (TG) in CAD is growing. Conversely, high-density lipoprotein cholesterol (HDL-C) variants not associated with LDL-C or TG have not yet been shown to be convincingly associated with CAD, raising questions about the causality of HDL-C in atherosclerosis. Finally, genetic variants at the LPA locus associated with lipoprotein(a) [Lp(a)] are decisively linked to CAD, indicating a causal role for Lp(a). Translational investigation of CAD-associated lipid variants may identify novel regulatory pathways with therapeutic potential to alter CAD risk.
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38
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Caussy C, Charrière S, Marçais C, Di Filippo M, Sassolas A, Delay M, Euthine V, Jalabert A, Lefai E, Rome S, Moulin P. An APOA5 3' UTR variant associated with plasma triglycerides triggers APOA5 downregulation by creating a functional miR-485-5p binding site. Am J Hum Genet 2014; 94:129-34. [PMID: 24387992 DOI: 10.1016/j.ajhg.2013.12.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 12/02/2013] [Indexed: 11/29/2022] Open
Abstract
APOA5 c.*158C>T (rs2266788), located in the 3' UTR, belongs to APOA5 haplotype 2 (APOA5*2), which is strongly associated with plasma triglyceride levels and modulates the occurrence of both moderate and severe hypertriglyceridemia. Individuals with APOA5*2 display reduced APOA5 expression at the posttranscriptional level. However, the functionality of this haplotype remains unclear. We hypothesized that the hypertriglyceridemic effects of APOA5*2 could involve miRNA regulation in the APOA5 3' UTR. Bioinformatic studies have identified the creation of a potential miRNA binding site for liver-expressed miR-485-5p (MIRN485-5p) in the mutant APOA5 3' UTR with the c.*158C allele. In human embryonic kidney 293T (HEK293T) cells cotransfected with an APOA5 3' UTR luciferase reporter vector and a miR485-5p precursor, c.*158C allele expression was significantly decreased. Moreover, in HuH-7 cells endogenously expressing miR-485-5p, we observed that luciferase activity was significantly lower in the presence of the c.*158C allele than in the presence of the c.*158T allele, which was completely reversed by a miR-485-5p inhibitor. We demonstrated that the rare c.*158C APOA5 allele creates a functional target site for liver-expressed miR-485-5p. Therefore, we propose that the well-documented hypertriglyceridemic effect of APOA5*2 involves an APOA5 posttranscriptional downregulation mediated by miR-485-5p.
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Affiliation(s)
- Cyrielle Caussy
- Fédération d'Endocrinologie, Maladies Métaboliques, Diabète, et Nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, 69677 Bron Cedex, France; Laboratoire Carmen, Institut National de la Santé et de la Recherche Médicale U1060, Institut National de la Recherche Agronomique U1235, Institut National des Sciences Appliquées de Lyon, Université Claude Bernard Lyon 1, 69621 Villeurbanne Cedex, France
| | - Sybil Charrière
- Fédération d'Endocrinologie, Maladies Métaboliques, Diabète, et Nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, 69677 Bron Cedex, France; Laboratoire Carmen, Institut National de la Santé et de la Recherche Médicale U1060, Institut National de la Recherche Agronomique U1235, Institut National des Sciences Appliquées de Lyon, Université Claude Bernard Lyon 1, 69621 Villeurbanne Cedex, France.
| | - Christophe Marçais
- Laboratoire Carmen, Institut National de la Santé et de la Recherche Médicale U1060, Institut National de la Recherche Agronomique U1235, Institut National des Sciences Appliquées de Lyon, Université Claude Bernard Lyon 1, 69621 Villeurbanne Cedex, France; Laboratoire de Biochimie Moléculaire et Métabolique, Centre de Biologie Sud, Centre Hospitalier Lyon-Sud, Hospices Civils de Lyon, 69495 Pierre-Bénite Cedex, France
| | - Mathilde Di Filippo
- Laboratoire Carmen, Institut National de la Santé et de la Recherche Médicale U1060, Institut National de la Recherche Agronomique U1235, Institut National des Sciences Appliquées de Lyon, Université Claude Bernard Lyon 1, 69621 Villeurbanne Cedex, France; Département de Biochimie et Biologie Moléculaire, Centre de Biologie et de Pathologie Est, Hospices Civils de Lyon, 69677 Bron Cedex, France
| | - Agnès Sassolas
- Laboratoire Carmen, Institut National de la Santé et de la Recherche Médicale U1060, Institut National de la Recherche Agronomique U1235, Institut National des Sciences Appliquées de Lyon, Université Claude Bernard Lyon 1, 69621 Villeurbanne Cedex, France; Département de Biochimie et Biologie Moléculaire, Centre de Biologie et de Pathologie Est, Hospices Civils de Lyon, 69677 Bron Cedex, France
| | - Mireille Delay
- Laboratoire de Biochimie Moléculaire et Métabolique, Centre de Biologie Sud, Centre Hospitalier Lyon-Sud, Hospices Civils de Lyon, 69495 Pierre-Bénite Cedex, France
| | - Vanessa Euthine
- Laboratoire Carmen, Institut National de la Santé et de la Recherche Médicale U1060, Institut National de la Recherche Agronomique U1235, Institut National des Sciences Appliquées de Lyon, Université Claude Bernard Lyon 1, 69621 Villeurbanne Cedex, France
| | - Audrey Jalabert
- Laboratoire Carmen, Institut National de la Santé et de la Recherche Médicale U1060, Institut National de la Recherche Agronomique U1235, Institut National des Sciences Appliquées de Lyon, Université Claude Bernard Lyon 1, 69621 Villeurbanne Cedex, France
| | - Etienne Lefai
- Laboratoire Carmen, Institut National de la Santé et de la Recherche Médicale U1060, Institut National de la Recherche Agronomique U1235, Institut National des Sciences Appliquées de Lyon, Université Claude Bernard Lyon 1, 69621 Villeurbanne Cedex, France
| | - Sophie Rome
- Laboratoire Carmen, Institut National de la Santé et de la Recherche Médicale U1060, Institut National de la Recherche Agronomique U1235, Institut National des Sciences Appliquées de Lyon, Université Claude Bernard Lyon 1, 69621 Villeurbanne Cedex, France
| | - Philippe Moulin
- Fédération d'Endocrinologie, Maladies Métaboliques, Diabète, et Nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, 69677 Bron Cedex, France; Laboratoire Carmen, Institut National de la Santé et de la Recherche Médicale U1060, Institut National de la Recherche Agronomique U1235, Institut National des Sciences Appliquées de Lyon, Université Claude Bernard Lyon 1, 69621 Villeurbanne Cedex, France
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Identification and characterization of cyclic AMP response element-binding protein H response element in the human apolipoprotein A5 gene promoter. BIOMED RESEARCH INTERNATIONAL 2013; 2013:892491. [PMID: 23957007 PMCID: PMC3730137 DOI: 10.1155/2013/892491] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 06/03/2013] [Accepted: 06/27/2013] [Indexed: 12/14/2022]
Abstract
The cyclic AMP response element-binding protein H (CREBH) plays important roles in hepatic lipogenesis, fatty acid oxidation, and lipolysis under metabolic stress. Here, we report CREBH as a novel regulator of human APOA5. Knockdown of endogenous CREBH expression via small interfering RNA resulted in the downregulation of human APOA5 mRNA expression in human hepatoma cells, HepG2. Sequence analysis suggested that putative CREBH response element (CREBHRE) is located in the human APOA5 promoter region and is highly conserved in both human and rodent. To clarify whether the human APOA5 promoter is regulated by CREBH, we analyzed the human APOA5 promoter region using a transient transfection assay and determined that transfection of CREBH induced human APOA5 promoter activity. Moreover, it was shown that CREBH directly regulated human APOA5 gene expression by binding to a unique CREBHRE located in the proximal human APOA5 promoter region, using 5′-deletion and mutagenesis of human APOA5 promoter analysis and chromatin immunoprecipitation assay. Taken together, our results demonstrated that human APOA5 is directly regulated by CREBH via CREBHRE and provided a new insight into the role of this liver-specific bZIP transcription factor in lipoprotein metabolism and triglyceride homeostasis.
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40
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Kim JY, Kim OY, Paik JK, Lee SH, Lee JH. Association of apolipoprotein A-V concentration with apolipoprotein A5 gene -1131T>C polymorphism and fasting triglyceride levels. J Clin Lipidol 2013; 7:94-101. [DOI: 10.1016/j.jacl.2012.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 05/29/2012] [Accepted: 06/20/2012] [Indexed: 12/25/2022]
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41
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Znf202 affects high density lipoprotein cholesterol levels and promotes hepatosteatosis in hyperlipidemic mice. PLoS One 2013; 8:e57492. [PMID: 23469003 PMCID: PMC3585336 DOI: 10.1371/journal.pone.0057492] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 01/22/2013] [Indexed: 11/19/2022] Open
Abstract
Background The zinc finger protein Znf202 is a transcriptional suppressor of lipid related genes and has been linked to hypoalphalipoproteinemia. A functional role of Znf202 in lipid metabolism in vivo still remains to be established. Methodology and Principal Findings We generated mouse Znf202 expression vectors, the functionality of which was established in several in vitro systems. Next, effects of adenoviral znf202 overexpression in vivo were determined in normo- as well as hyperlipidemic mouse models. Znf202 overexpression in mouse hepatoma cells mhAT3F2 resulted in downregulation of members of the Apoe/c1/c2 and Apoa1/c3/a4 gene cluster. The repressive activity of Znf202 was firmly confirmed in an apoE reporter assay and Znf202 responsive elements within the ApoE promoter were identified. Adenoviral Znf202 transfer to Ldlr−/− mice resulted in downregulation of apoe, apoc1, apoa1, and apoc3 within 24 h after gene transfer. Interestingly, key genes in bile flux (abcg5/8 and bsep) and in bile acid synthesis (cyp7a1) were also downregulated. At 5 days post-infection, the expression of the aforementioned genes was normalized, but mice had developed severe hepatosteatosis accompanied by hypercholesterolemia and hypoalphalipoproteinemia. A much milder phenotype was observed in wildtype mice after 5 days of hepatic Znf202 overexpression. Interestingly and similar to Ldl−/− mice, HDL-cholesterol levels in wildtype mice were lowered after hepatic Znf202 overexpression. Conclusion/Significance Znf202 overexpression in vivo reveals an important role of this transcriptional regulator in liver lipid homeostasis, while firmly establishing the proposed key role in the control of HDL levels.
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The polymorphism -1131T>C in apolipoprotein A5 gene is associated with dyslipidemia in Brazilian subjects. Gene 2012; 516:171-5. [PMID: 23266809 DOI: 10.1016/j.gene.2012.12.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 10/18/2012] [Accepted: 12/02/2012] [Indexed: 02/07/2023]
Abstract
BACKGROUND Polymorphisms in apolipoprotein A5 gene (APOA5) have been associated with higher triglyceride levels in many populations. The aim of the study was to determine the allelic and genotypic distribution of the APOA5 -1131T>C polymorphism and to identify the association of the genetic variant and the risk for dyslipidemia. METHODS We genotyped 109 dyslipidemic subjects and 107 controls. The total cholesterol, triglycerides and HDL-c were determined enzymatically. Comparison of means among groups was calculated by ANOVA. Significant differences among groups were evaluated by Student-Newman-Keuls test. RESULTS The minor allele C was more frequent in dyslipidemic subjects than controls (p=0.019) and confers an increased individual risk for dyslipidemia (OR=1.726, CI 95%=1.095-2.721). The genotype analysis by gender showed that this allele was more frequent in dyslipidemic males (p=0.037; OR=2.050, CI 95%=1.042-4.023). When participants were analyzed according to genotypes TT and TC/CC, C-carriers presented higher cholesterol and triglycerides levels than TT homozygous (p=0.046 and 0.049, respectively). CONCLUSIONS The allele C confers higher total cholesterol and triglycerides levels in dyslipidemic adults. The APOA5 -1131T>C polymorphism is associated with dyslipidemia in male subjects.
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Jiang ZG, Robson SC, Yao Z. Lipoprotein metabolism in nonalcoholic fatty liver disease. J Biomed Res 2012; 27:1-13. [PMID: 23554788 PMCID: PMC3596749 DOI: 10.7555/jbr.27.20120077] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 08/23/2012] [Accepted: 08/29/2012] [Indexed: 12/18/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD), an escalating health problem worldwide, covers a spectrum of pathologies characterized by fatty accumulation in hepatocytes in early stages, with potential progression to liver inflammation, fibrosis, and failure. A close, yet poorly understood link exists between NAFLD and dyslipidemia, a constellation of abnormalities in plasma lipoproteins including triglyceride-rich very low density lipoproteins. Apolipoproteins are a group of primarily liver-derived proteins found in serum lipoproteins; they not only play an extracellular role in lipid transport between vital organs through circulation, but also play an important intracellular role in hepatic lipoprotein assembly and secretion. The liver functions as the central hub for lipoprotein metabolism, as it dictates lipoprotein production and to a significant extent modulates lipoprotein clearance. Lipoprotein metabolism is an integral component of hepatocellular lipid homeostasis and is implicated in the pathogenesis, potential diagnosis, and treatment of NAFLD.
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Affiliation(s)
- Zhenghui Gordon Jiang
- Department of Medicine, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, USA
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Dussaillant C, Serrano V, Maiz A, Eyheramendy S, Cataldo LR, Chavez M, Smalley SV, Fuentes M, Rigotti A, Rubio L, Lagos CF, Martinez JA, Santos JL. APOA5 Q97X mutation identified through homozygosity mapping causes severe hypertriglyceridemia in a Chilean consanguineous family. BMC MEDICAL GENETICS 2012; 13:106. [PMID: 23151256 PMCID: PMC3523038 DOI: 10.1186/1471-2350-13-106] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 10/23/2012] [Indexed: 12/31/2022]
Abstract
Background Severe hypertriglyceridemia (HTG) has been linked to defects in LPL, APOC2, APOA5, LMF1 and GBIHBP1 genes. However, a number of severe HTG cases are probably caused by as yet unidentified mutations. Very high triglyceride plasma levels (>112 mmol/L at diagnosis) were found in two sisters of a Chilean consanguineous family, which is strongly suggestive of a recessive highly penetrant mutation. The aim of this study was to determine the genetic locus responsible for the severe HTG in this family. Methods We carried out a genome-wide linkage study with nearly 300,000 biallelic markers (Illumina Human CytoSNP-12 panel). Using the homozygosity mapping strategy, we searched for chromosome regions with excess of homozygous genotypes in the affected cases compared to non-affected relatives. Results A large homozygous segment was found in the long arm of chromosome 11, with more than 2,500 consecutive homozygous SNP shared by the proband with her affected sister, and containing the APOA5/A4/C3/A1 cluster. Direct sequencing of the APOA5 gene revealed a known homozygous nonsense Q97X mutation (p.Gln97Ter) found in both affected sisters but not in non-affected relatives nor in a sample of unrelated controls. Conclusion The Q97X mutation of the APOA5 gene in homozygous status is responsible for the severe hypertriglyceridemia in this family. We have shown that homozygosity mapping correctly pinpointed the genomic region containing the gene responsible for severe hypertriglyceridemia in this consanguineous Chilean family.
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Affiliation(s)
- Catalina Dussaillant
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Alameda, Santiago, Chile
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Garelnabi M, Lor K, Jin J, Chai F, Santanam N. The paradox of ApoA5 modulation of triglycerides: evidence from clinical and basic research. Clin Biochem 2012; 46:12-9. [PMID: 23000317 DOI: 10.1016/j.clinbiochem.2012.09.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 08/13/2012] [Accepted: 09/10/2012] [Indexed: 01/02/2023]
Abstract
UNLABELLED Apolipoprotein A5 (ApoA5) is a key regulator of plasma triglycerides (TG), even though its plasma concentration is very low compared to other known apoproteins. Over the years, researchers have attempted to elucidate the molecular mechanisms by which ApoA5 regulates plasma TG in vivo. Though still under debate, two theories broadly describe how ApoA5 modulates TG levels: (i) ApoA5 enhances the catabolism of TG-rich lipoproteins and (ii) it inhibits the rate of production of very low-density lipoprotein (VLDL), the major carrier of TGs. This review will summarize the basic and clinical studies that describe the importance of ApoA5 in TG metabolism. Population studies conducted in various countries have demonstrated an association between single nucleotide polymorphisms (SNPs) in ApoA5 and the increased risk to cardiovascular disease and metabolic syndrome (including diabetes and obesity). ApoA5 is also highly expressed during liver regeneration and is an acute phase protein associated with HDL, which is independent of its effects on TG metabolism. CONCLUSION Despite considerable evidences available from clinical and basic research studies on the role of ApoA5 in TG metabolism and its indirect link to metabolic diseases, additional investigations are needed to understand the paradoxical role of this important apoprotein is modulated by both diet and its polymorphism variants.
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Affiliation(s)
- Mahdi Garelnabi
- Department of Clinical Laboratory and Nutritional Sciences, University of Massachusetts Lowell, MA 01854, USA.
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Gao X, Forte TM, Ryan RO. Influence of apolipoprotein A-V on hepatocyte lipid droplet formation. Biochem Biophys Res Commun 2012; 427:361-5. [PMID: 23000161 DOI: 10.1016/j.bbrc.2012.09.065] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 09/11/2012] [Indexed: 11/30/2022]
Abstract
Apolipoprotein A-V (apoA-V) is postulated to modulate intra-hepatic triglyceride (TG) trafficking. Stably transfected McA-RH7777 hepatocarcinoma cells expressing human apoA-V displayed enhanced neutral lipid staining while conditioned media from these cells had 40±8% less TG than cells transfected with a control vector. To obtain homogeneous cell lines expressing different amounts of apoA-V, a strategy of clonal selection was pursued. Immunoblot analysis of two distinct apoA-V stable cell lines yielded one that expresses low amounts of apoA-V and another that expresses higher amounts. Confocal fluorescence microscopy of control cells and cells expressing low levels of apoA-V had similar numbers of lipid droplets while cells expressing higher amounts of apoA-V had twice as many lipid droplets, on average. Thus, apoA-V expression promotes lipid droplet accumulation in these cells.
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Affiliation(s)
- Xuan Gao
- Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609, USA
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Liu CF, Yang QF, Chen XL, Liu CY. Apolipoprotein a5 gene polymorphism and risk for metabolic syndrome: a meta-analysis. Genet Test Mol Biomarkers 2012; 16:1241-5. [PMID: 22905904 DOI: 10.1089/gtmb.2012.0183] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND Many studies have focused on the association between the apolipoprotein A5 (ApoA5) polymorphism and the risk of metabolic syndrome (MetS). However, these studies drew inconsistent conclusions. The aim of this study was to evaluate the exact association between the ApoA5 polymorphism and MetS in a large-scale meta-analysis. METHODS The PubMed, Embase, and Science Citation Index (ISI Web of Science) databases were searched to collect all publications on the association between the ApoA5 polymorphism and MetS. Two common variants of ApoA5 (namely -1131T>C in the promoter region and c.56C>G in the coding region) with the risk of MetS were analyzed. The overall odd ratios (ORs) and 95% confidence intervals (CIs) for -1131T>C (CC+TC) versus TT genotype and c.C56G (GG+GC) versus CC were assessed between the MetS and control group. Subgroup analysis was further performed by ethnicity. The meta-analysis was performed by Stata11.0. RESULTS Twelve studies from 10 publications were chosen in our meta-analysis. The combined results showed that C allele carriers (CC+TC) of -1131T>C had a significantly higher risk of MetS for the overall (OR=1.32; 95% CI: 1.14-1.53; p=0.000) with moderate heterogeneity (I2=54.9%, p=0.014). Subgroup analysis was further performed according to ethnicity, and the association was still significant in Asians (OR=1.42; 95% CI: 1.25-1.62; p=0.000), but not in white populations (OR=1.25; 95% CI: 0.97-1.61; p=0.087). When analyzing the association between c.C56G and MetS, the G allele carrier (GG+GC) genotype significantly increased the risk of MetS (OR=1.32; 95% CI: 1.15-1.50; p=0.000) in white populations. No significant publication bias was observed in either -1131T>C or c.C56G. CONCLUSIONS Our study suggested that the ApoA5 -1131T>C polymorphism was significantly associated with the risk of MetS in Asians, but not in white populations. However, the c.C56G polymorphism was significantly associated with MetS in white populations.
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Affiliation(s)
- Cun-Fei Liu
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
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Al-Zoairy R, Melmer A, Ress C, Laimer M, Kaser S, Ebenbichler C. Lipid profile changes after pronounced weight loss induced by bariatric surgery. ACTA ACUST UNITED AC 2012. [DOI: 10.2217/clp.12.9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Yang Y, Walijee SM, Jin J, Zhao SP, Peng DQ. Serum apolipoprotein A-V in patients with coronary artery disease and its association with triglyceride. J Clin Lipidol 2012; 6:462-8. [PMID: 23009782 DOI: 10.1016/j.jacl.2012.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 02/06/2012] [Accepted: 02/13/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND Apolipoprotein A-V (ApoA-V) has been shown to play an important role in the metabolism of plasma triglyceride (TG) levels. However, data for the relationship between serum ApoA-V and TG level and the association between ApoA-V levels and the risk of coronary artery disease (CAD) are inconsistent. OBJECTIVE To investigate plasma ApoA-V level and its association with TG in patients with CAD determined by angiography. METHODS Three hundred forty subjects who underwent coronary angiography (CAG) were classified into a CAD group (n = 211) and a non-CAD group (n = 129) according to the results of their CAG. Serum ApoA-V levels were determined by enzyme-linked immunosorbent assays. RESULTS Patients in the CAD group had greater ApoA-V levels than controls (192.0 ± 114.6 ng/mL vs 164.4 ± 107.5 ng/mL, P < .05). The concentration of ApoA-V was positively correlated to TG level (r = 0.229, P < .01). This correlation was more intense in non-CAD group (r = 0.306, P < .01) than in CAD group (r = 0.172, P < .05). ApoA-V was positively associated with Gensini score. However, the contribution of ApoA-V to Gensini score and CAD risk disappeared after adjustment for the TG level. CONCLUSION The positive correlation between serum ApoA-V and TG differs in strength between control and CAD patients. The correlation between ApoA-V and CAD is confounded by the effect of TG. We speculate that the increase of ApoA-V may be a consequence of compensation for the increased demand for plasma TG hydrolysis.
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Affiliation(s)
- Yang Yang
- Department of Cardiology, The Second Xiangya Hospital, Central South University, Changsha, 410011 Hunan, PR China
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Sharma V, Ryan RO, Forte TM. Apolipoprotein A-V dependent modulation of plasma triacylglycerol: a puzzlement. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:795-9. [PMID: 22209939 DOI: 10.1016/j.bbalip.2011.12.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 12/12/2011] [Accepted: 12/13/2011] [Indexed: 02/07/2023]
Abstract
The discovery of apolipoprotein A-V (apoA-V) in 2001 has raised a number of intriguing questions about its role in lipid transport and triglyceride (TG) homeostasis. Genome wide association studies (GWAS) have consistently identified APOA5 as a contributor to plasma TG levels. Single nucleotide polymorphisms (SNP) within the APOA5 gene locus have been shown to correlate with elevated plasma TG. Furthermore, transgenic and knockout mouse models support the view that apoA-V plays a critical role in maintenance of plasma TG levels. The present review describes recent concepts pertaining to apoA-V SNP analysis and their association with elevated plasma TG. The interaction of apoA-V with glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 (GPIHBP1) is discussed relative to its postulated role in TG-rich lipoprotein catabolism. The potential role of intracellular apoA-V in regulation of TG homeostasis, as a function of its ability to associate with cytosolic lipid droplets, is reviewed. While some answers are emerging, numerous mysteries remain with regard to this low abundance, yet potent, modulator of TG homeostasis. Given the strong correlation between elevated plasma TG and heart disease, there is great scientific and public interest in deciphering the numerous biological riddles presented by apoA-V. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.
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Affiliation(s)
- Vineeta Sharma
- Center for Prevention of Obesity, Diabetes, and Cardiovascular Disease, Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA
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