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Reyes-Soffer G, Sztalryd C, Horenstein RB, Holleran S, Matveyenko A, Thomas T, Nandakumar R, Ngai C, Karmally W, Ginsberg HN, Ramakrishnan R, Pollin TI. Effects of APOC3 Heterozygous Deficiency on Plasma Lipid and Lipoprotein Metabolism. Arterioscler Thromb Vasc Biol 2019; 39:63-72. [PMID: 30580564 DOI: 10.1161/atvbaha.118.311476] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Objective- Apo (apolipoprotein) CIII inhibits lipoprotein lipase (LpL)-mediated lipolysis of VLDL (very-low-density lipoprotein) triglyceride (TG) and decreases hepatic uptake of VLDL remnants. The discovery that 5% of Lancaster Old Order Amish are heterozygous for the APOC3 R19X null mutation provided the opportunity to determine the effects of a naturally occurring reduction in apo CIII levels on the metabolism of atherogenic containing lipoproteins. Approach and Results- We conducted stable isotope studies of VLDL-TG and apoB100 in 5 individuals heterozygous for the null mutation APOC3 R19X (CT) and their unaffected (CC) siblings. Fractional clearance rates and production rates of VLDL-TG and apoB100 in VLDL, IDL (intermediate-density lipoprotein), LDL, apo CIII, and apo CII were determined. Affected (CT) individuals had 49% reduction in plasma apo CIII levels compared with CCs ( P<0.01) and reduced plasma levels of TG (35%, P<0.02), VLDL-TG (45%, P<0.02), and VLDL-apoB100 (36%, P<0.05). These changes were because of higher fractional clearance rates of VLDL-TG and VLDL-apoB100 with no differences in production rates. CTs had higher rates of the conversion of VLDL remnants to LDL compared with CCs. In contrast, rates of direct removal of VLDL remnants did not differ between the groups. As a result, the flux of apoB100 from VLDL to LDL was not reduced, and the plasma levels of LDL-cholesterol and LDL-apoB100 were not lower in the CT group. Apo CIII production rate was lower in CTs compared with CCs, whereas apo CII production rate was not different between the 2 groups. The fractional clearance rates of both apo CIII and apo CII were higher in CTs than CCs. Conclusions- These studies demonstrate that 50% reductions in plasma apo CIII, in otherwise healthy subjects, results in a significantly higher rate of conversion of VLDL to LDL, with little effect on direct hepatic uptake of VLDL. When put in the context of studies demonstrating significant protection from cardiovascular events in individuals with loss of function variants in the APOC3 gene, our results provide strong evidence that therapies which increase the efficiency of conversion of VLDL to LDL, thereby reducing remnant concentrations, should reduce the risk of cardiovascular disease.
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Affiliation(s)
- Gissette Reyes-Soffer
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Carol Sztalryd
- Maryland School of Medicine, University of Maryland, Baltimore (C.S., R.B.H., T.I.P.)
- Baltimore VA Medical Center, VA Research Service, Geriatric Research, Education and Clinical Center and VA Maryland Health Care System (C.S., T.I.P.)
| | - Richard B Horenstein
- Maryland School of Medicine, University of Maryland, Baltimore (C.S., R.B.H., T.I.P.)
| | - Stephen Holleran
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Anastasiya Matveyenko
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Tiffany Thomas
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Renu Nandakumar
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Colleen Ngai
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Wahida Karmally
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Henry N Ginsberg
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Rajasekhar Ramakrishnan
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Toni I Pollin
- Maryland School of Medicine, University of Maryland, Baltimore (C.S., R.B.H., T.I.P.)
- Baltimore VA Medical Center, VA Research Service, Geriatric Research, Education and Clinical Center and VA Maryland Health Care System (C.S., T.I.P.)
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Update on the molecular biology of dyslipidemias. Clin Chim Acta 2016; 454:143-85. [DOI: 10.1016/j.cca.2015.10.033] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/24/2015] [Accepted: 10/30/2015] [Indexed: 12/20/2022]
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Jiang J, Wang Y, Ling Y, Kayoumu A, Liu G, Gao X. A novel APOC2 gene mutation identified in a Chinese patient with severe hypertriglyceridemia and recurrent pancreatitis. Lipids Health Dis 2016; 15:12. [PMID: 26772541 PMCID: PMC4715280 DOI: 10.1186/s12944-015-0171-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 12/29/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The severe forms of hypertriglyceridemia are usually caused by genetic defects. In this study, we described a Chinese female with severe hypertriglyceridemia caused by a novel homozygous mutation in the APOC2 gene. METHODS Lipid profiles of the pedigree were studied in detail. LPL and HL activity were also measured. The coding regions of 5 candidate genes (namely LPL, APOC2, APOA5, LMF1, and GPIHBP1) were sequenced using genomic DNA from peripheral leucocytes. The ApoE gene was also genotyped. RESULTS Serum triglyceride level was extremely high in the proband, compared with other family members. Plasma LPL activity was also significantly reduced in the proband. Serum ApoCII was very low in the proband as well as in the heterozygous mutation carriers. A novel mutation (c.86A > CC) was identified on exon 3 [corrected] of the APOC2 gene, which converted the Asp [corrected] codon at position 29 into Ala, followed by a termination codon (TGA). CONCLUSIONS This study presented the first case of ApoCII deficiency in the Chinese population, with a novel mutation c.86A > CC in the APOC2 gene identified. Serum ApoCII protein might be a useful screening test for identifying mutation carriers.
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Affiliation(s)
- Jingjing Jiang
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yuhui Wang
- Institute of Cardiovascular Science, Peking University and Key laborotory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - Yan Ling
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Abudurexiti Kayoumu
- Institute of Cardiovascular Science, Peking University and Key laborotory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - George Liu
- Institute of Cardiovascular Science, Peking University and Key laborotory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - Xin Gao
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China.
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Li P, Ruan X, Yang L, Kiesewetter K, Zhao Y, Luo H, Chen Y, Gucek M, Zhu J, Cao H. A liver-enriched long non-coding RNA, lncLSTR, regulates systemic lipid metabolism in mice. Cell Metab 2015; 21:455-67. [PMID: 25738460 PMCID: PMC4350020 DOI: 10.1016/j.cmet.2015.02.004] [Citation(s) in RCA: 223] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 12/12/2014] [Accepted: 02/06/2015] [Indexed: 02/01/2023]
Abstract
Long non-coding RNAs (lncRNAs) constitute a significant portion of mammalian genome, yet the physiological importance of lncRNAs is largely unknown. Here, we identify a liver-enriched lncRNA in mouse that we term liver-specific triglyceride regulator (lncLSTR). Mice with a liver-specific depletion of lncLSTR exhibit a marked reduction in plasma triglyceride levels. We show that lncLSTR depletion enhances apoC2 expression, leading to robust lipoprotein lipase activation and increased plasma triglyceride clearance. We further demonstrate that the regulation of apoC2 expression occurs through an FXR-mediated pathway. LncLSTR forms a molecular complex with TDP-43 to regulate expression of Cyp8b1, a key enzyme in the bile acid synthesis pathway, and engenders an in vivo bile pool that induces apoC2 expression through FXR. Finally, we demonstrate that lncLSTR depletion can reduce triglyceride levels in a hyperlipidemia mouse model. Taken together, these data support a model in which lncLSTR regulates a TDP-43/FXR/apoC2-dependent pathway to maintain systemic lipid homeostasis.
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Affiliation(s)
- Ping Li
- Center for Molecular Medicine, National Heart, Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Xiangbo Ruan
- Center for Molecular Medicine, National Heart, Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Ling Yang
- Center for Molecular Medicine, National Heart, Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Kurtis Kiesewetter
- Center for Molecular Medicine, National Heart, Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Yi Zhao
- Key Laboratory of Intelligent Information Processing, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, PR China
| | - Haitao Luo
- Key Laboratory of Intelligent Information Processing, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, PR China
| | - Yong Chen
- Proteomics Core, National Heart, Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Marjan Gucek
- Proteomics Core, National Heart, Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Jun Zhu
- Systems Biology Center, National Heart, Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Haiming Cao
- Center for Molecular Medicine, National Heart, Lung and Blood Institute, NIH, Bethesda, MD 20892, USA.
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Kei AA, Filippatos TD, Tsimihodimos V, Elisaf MS. A review of the role of apolipoprotein C-II in lipoprotein metabolism and cardiovascular disease. Metabolism 2012; 61:906-21. [PMID: 22304839 DOI: 10.1016/j.metabol.2011.12.002] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 12/06/2011] [Accepted: 12/08/2011] [Indexed: 12/21/2022]
Abstract
The focus of this review is on the role of apolipoprotein C-II (apoC-II) in lipoprotein metabolism and the potential effects on the risk of cardiovascular disease (CVD). We searched PubMed/Scopus for articles regarding apoC-II and its role in lipoprotein metabolism and the risk of CVD. Apolipoprotein C-II is a constituent of chylomicrons, very low-density lipoprotein, low-density lipoprotein, and high-density lipoprotein (HDL). Apolipoprotein C-II contains 3 amphipathic α-helices. The lipid-binding domain of apoC-II is located in the N-terminal, whereas the C-terminal helix of apoC-II is responsible for the interaction with lipoprotein lipase (LPL). At intermediate concentrations (approximately 4 mg/dL) and in normolipidemic subjects, apoC-II activates LPL. In contrast, both an excess and a deficiency of apoC-II are associated with reduced LPL activity and hypertriglyceridemia. Furthermore, excess apoC-II has been associated with increased triglyceride-rich particles and alterations in HDL particle distribution, factors that may increase the risk of CVD. However, there is not enough current evidence to clarify whether increased apoC-II causes hypertriglyceridemia or is an epiphenomenon reflecting hypertriglyceridemia. A number of pharmaceutical interventions, including statins, fibrates, ezetimibe, nicotinic acid, and orlistat, have been shown to reduce the increased apoC-II concentrations. An excess of apoC-II is associated with increased triglyceride-rich particles and alterations in HDL particle distribution. However, prospective trials are needed to assess if apoC-II is a CVD marker or a risk factor in high-risk patients.
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Affiliation(s)
- Anastazia A Kei
- Department of Internal Medicine, School of Medicine, University of Ioannina, 45 110 Ioannina, Greece
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Abstract
Plasma lipid disorders can occur either as a primary event or secondary to an underlying disease or use of medications. Familial dyslipidaemias are traditionally classified according to the electrophoretic profile of lipoproteins. In more recent texts, this phenotypic classification has been replaced with an aetiological classification. Familial dyslipidaemias are generally grouped into disorders leading to hypercholesterolaemia, hypertriglyceridaemia, a combination of hyper-cholesterolaemia and hypertriglyceridaemia, or abnormal high-density lipoprotein-cholesterol (HDL-C) levels. The management of these disorders requires an understanding of plasma lipid and lipoprotein metabolism. Lipid transport and metabolism involves three general pathways: (i) the exogenous pathway, whereby chylomicrons are synthesised by the small intestine, and dietary triglycerides (TGs) and cholesterol are transported to various cells of the body; (ii) the endogenous pathway, whereby very low-density lipoprotein-cholesterol (VLDL-C) and TGs are synthesised by the liver for transport to various tissues; and (iii) the reverse cholesterol transport, whereby HDL cholesteryl ester is exchanged for TGs in low-density lipoptrotein (LDL) and VLDL particles through cholesteryl ester transfer protein in a series of steps to remove cholesterol from the peripheral tissues for delivery to the liver and steroidogenic organs. The plasma lipid profile can provide a framework to guide the selection of appropriate diet and drug treatment. Many patients with hyperlipoproteinaemia can be treated effectively with diet. However, dietary regimens are often insufficient to bring lipoprotein levels to within acceptable limits. In this article, we review lipid transport and metabolism, discuss the more common lipid disorders and suggest some management guidelines. The choice of a particular agent depends on the baseline lipid profile achieved after 6-12 weeks of intense lifestyle changes and possible use of dietry supplements such as stanols and plant sterols. If the predominant lipid abnormality is hypertriglyceridaemia, omega-3 fatty acids, a fibric acid derivative (fibrate) or nicotinic acid would be considered as the first choice of therapy. In subsequent follow-up, when LDL-C is >130 mg/dL (3.36 mmol/L) then an HMG-CoA reductase inhibitor (statin) should be added as a combination therapy. If the serum TG levels are <500 mg/dL (2.26 mmol/L) and the LDL-C values are over 130 mg/dL (3.36 mmol/L) then a statin would be the first drug of choice. The statin dose can be titrated up to achieve the therapeutic goal or, alternatively, ezetimibe can be added. A bile acid binding agent is an option if the serum TG levels do not exceed 200 mg/dL (5.65 mmol/L), otherwise a fibrate or nicotinic acid should be considered. The decision to treat a particular person has to be individualised.
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Affiliation(s)
- Sahar B Hachem
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, Saint Louis University School of Medicine, Saint Louis, Missouri, USA
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Nelsestuen GL, Zhang Y, Martinez MB, Key NS, Jilma B, Verneris M, Sinaiko A, Kasthuri RS. Plasma protein profiling: unique and stable features of individuals. Proteomics 2006; 5:4012-24. [PMID: 16130168 DOI: 10.1002/pmic.200401234] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Carefully controlled ZipTip extraction of diluted human plasma or serum was combined with MALDI-TOF-MS to produce highly reproducible protein profiles. Components detected included apolipoproteins CI, CII and CIII as well as transthyretin and several isoforms of each protein that are created by glycosylation or other modification and by proteolytic processing. Profiles of healthy individuals all contained the same 15 components. Others were found in plasma from individuals with disease. Profiles were analyzed by peak ratios within the same spectrum. Reproducibility for multiple assays was generally 4 to 10%. Within the healthy population, a given peak ratio occurred with a range of about fourfold. However, peak ratios of multiple samples from the same individual showed a much lower range, typically +/-10%. In fact, each individual displayed a personal protein profile that changed very little over time. Because of the stability of protein profiles over time within individuals, these results suggest further studies may discover that certain profile characteristics or changes in an individual's profile may be a sign of current or future disease, even when the altered profile remains within the range for healthy individuals.
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Affiliation(s)
- Gary L Nelsestuen
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
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Nauck MS, Nissen H, Hoffmann MM, Herwig J, Pullinger CR, Averna M, Geisel J, Wieland H, März W. Detection of mutations in the apolipoprotein CII gene by denaturing gradient gel electrophoresis. Identification of the splice site variant apolipoprotein CII-Hamburg in a patient with severe hypertriglyceridemia. Clin Chem 1998. [DOI: 10.1093/clinchem/44.7.1388] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractFamilial apolipoprotein (apo) CII deficiency is a rare autosomal recessive inborn error of metabolism clinically resembling lipoprotein lipase deficiency. A number of mutations of the apo CII gene are known to date; they are located in the promoter region, the coding exons, or in the splice junctions. We present a simple assay based on PCR and denaturing gradient gel electrophoresis, which allows scanning of the promoter, the entire coding sequence, and the splice junctions of the apo CII gene for sequence variants. All gene fragments are amplified using a common PCR protocol and are examined for mutations on a single gradient gel. Using this method and direct sequencing, we identified homozygosity for a donor splice-site mutation in the second intron, previously designated apo CII-Hamburg, as the genetic cause of apo CII deficiency in a 9-year-old boy presenting with chylomicronemia, eruptive xanthoma, and pancreatitis. In addition, the method allowed us to detect all of six different other known mutations of the apo CII gene. We conclude, therefore, that our assay is highly sensitive; in addition, it is easy to perform and may facilitate the differential diagnosis of disorders of lipoprotein metabolism at the genetic level.
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Affiliation(s)
- Markus S Nauck
- Division of Clinical Chemistry, Department of Medicine, Albert Ludwigs-University, 79106 Freiburg, Germany
| | - Henrik Nissen
- Department of Clinical Chemistry, University Hospital, 5000 Odense, Denmark
| | - Michael M Hoffmann
- Division of Clinical Chemistry, Department of Medicine, Albert Ludwigs-University, 79106 Freiburg, Germany
| | - Jürgen Herwig
- Department of Pediatrics, Johann Wolfgang Goethe-University, 60590 Frankfurt, Germany
| | - Clive R Pullinger
- Cardiovascular Research Institute, University of California, San Francisco, CA 94143-0131
| | - Maurizio Averna
- Lipid Research and Atherosclerosis Center, Institute of Internal Medicine and Geriatry, University of Palermo, 90127 Palermo, Italy
| | - Jürgen Geisel
- Klinisch-Chemisches Zentrallabor der Universitätskliniken des Saarlandes, 66421 Homburg/Saar, Germany
| | - Heinrich Wieland
- Division of Clinical Chemistry, Department of Medicine, Albert Ludwigs-University, 79106 Freiburg, Germany
| | - Winfried März
- Division of Clinical Chemistry, Department of Medicine, Albert Ludwigs-University, 79106 Freiburg, Germany
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