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Mooij HL, Bernelot Moens SJ, Gordts PSM, Stanford K, Foley E, van den Boogert MW, Witjes J, Hassing HC, Tanck M, van de Sande MJ, Levels JH, Kastelein JP, Stroes EG, Dallinga-Thie G, Esko J, Nieuwdorp M. Ext1 heterozygosity causes a modest effect on postprandial lipid clearance in humans. J Lipid Res 2015; 56:665-673. [PMID: 25568062 DOI: 10.1194/jlr.m053504] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Elevated nonfasting TG-rich lipoprotein levels are a risk factor for CVD. To further evaluate the relevance of LDL-receptor (LDLr) pathway and heparan sulfate proteoglycans (HSPGs) in TG homeostasis, we analyzed fasting and postprandial TG levels in mice bearing combined heterozygous mutations in both Exostosin (Ext) 1 and Ldlr, in subjects with hereditary multiple exostosis (HME) due to a heterozygous loss-of-function mutation in EXT1 or EXT2 (N = 13), and in patients with heterozygous mutations in LDLR [familial hypercholesterolemia (FH)] and SNPs in major HSPG-related genes (n = 22). Mice bearing a homozygous mutation in hepatic Ext1 exhibited elevated plasma TGs similar to mice lacking other key enzymes involved in HSPG assembly. Compound heterozygous mice lacking Ldlr and Ext1 showed synergy on plasma TG accumulation and postprandial clearance. In human subjects, a trend was observed in HME patients toward reduced postprandial TG clearance with a concomitant reduction in chylomicron clearance [area under the curve (AUC)-retinyl ester (RE) HME, 844 ± 127 vs. controls, 646 ± 119 nM/h, P = 0.09]. Moreover, in FH subjects with a high HSPG gene score, retinyl palmitate excursions were higher (AUC-RE, 2,377 ± 293 vs. 1,565 ± 181 nM/h, P < 0.05). Incremental AUC-apoB48 was similar between the groups. In conclusion, the data are supportive for a minor yet additive role of HSPG in human postprandial TG clearance, and further studies are warranted.
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Affiliation(s)
| | | | - PhilipL S M Gordts
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA
| | - KristinI Stanford
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA
| | - ErinM Foley
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA
| | | | | | | | - MichaelW Tanck
- Department of Clinical Epidemiology, Biostatistics and Bioinformatics
| | | | - J Han Levels
- Department of Experimental Vascular Medicine, Academic Medical Center, Amsterdam, the Netherlands
| | | | | | - GeesjeM Dallinga-Thie
- Department of Vascular Medicine; Department of Experimental Vascular Medicine, Academic Medical Center, Amsterdam, the Netherlands
| | - JeffD Esko
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA
| | - Max Nieuwdorp
- Department of Vascular Medicine; Department of Experimental Vascular Medicine, Academic Medical Center, Amsterdam, the Netherlands.
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53
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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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56
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Sharma V, Witkowski A, Witkowska HE, Dykstra A, Simonsen JB, Nelbach L, Beckstead JA, Pullinger CR, Kane JP, Malloy MJ, Watson G, Forte TM, Ryan RO. Aberrant hetero-disulfide bond formation by the hypertriglyceridemia-associated p.Gly185Cys APOA5 variant (rs2075291). Arterioscler Thromb Vasc Biol 2014; 34:2254-60. [PMID: 25127531 DOI: 10.1161/atvbaha.114.304027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE Apolipoprotein A-V (apoA-V) is a low-abundance plasma protein that modulates triacylglycerol homeostasis. Gene transfer studies were undertaken in apoa5 (-/-) mice to define the mechanism underlying the correlation between the single-nucleotide polymorphism c.553G>T in APOA5 and hypertriglyceridemia. APPROACH AND RESULTS Adeno-associated virus (AAV) 2/8-mediated gene transfer of wild-type apoA-V induced a dramatic lowering of plasma triacylglycerol in apoa5 (-/-) mice, whereas AAV2/8-Gly162Cys apoA-V (corresponding to the c.553G>T single-nucleotide polymorphism: rs2075291; p.Gly185Cys when numbering includes signal sequence) had a modest effect. Characterization studies revealed that plasma levels of wild-type and G162C apoA-V in transduced mice were similar and within the physiological range. Fractionation of plasma from mice transduced with AAV2/8-G162C apoA-V indicated that, unlike wild-type apoA-V, >50% of G162C apoA-V was recovered in the lipoprotein-free fraction. Nonreducing SDS-PAGE immunoblot analysis provided evidence that G162C apoA-V present in the lipoprotein-free fraction, but not that portion associated with lipoproteins, displayed altered electrophoretic mobility consistent with disulfide-linked heterodimer formation. Immunoprecipitation followed by liquid chromatography/mass spectrometry of human plasma from subjects homozygous for wild-type APOA5 and c.553G>T APOA5 revealed that G162C apoA-V forms adducts with extraneous plasma proteins including fibronectin, kininogen-1, and others. CONCLUSIONS Substitution of Cys for Gly at position 162 of mature apoA-V introduces a free cysteine that forms disulfide bonds with plasma proteins such that its lipoprotein-binding and triacylglycerol-modulation functions are compromised.
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Affiliation(s)
- Vineeta Sharma
- From the Children's Hospital Oakland Research Institute, CA (V.S., A.W., J.B.S., L.N., J.A.B., G.W., T.M.F., R.O.R.); Department of Obstetrics, Gynecology and Reproductive Sciences, UCSF Sandler-Moore Mass Spectrometry Core Facility, San Francisco, CA (H.E.W., A.D.); and Cardiovascular Research Institute, University of California, San Francisco (C.R.P., J.P.K., M.J.M.)
| | - Andrzej Witkowski
- From the Children's Hospital Oakland Research Institute, CA (V.S., A.W., J.B.S., L.N., J.A.B., G.W., T.M.F., R.O.R.); Department of Obstetrics, Gynecology and Reproductive Sciences, UCSF Sandler-Moore Mass Spectrometry Core Facility, San Francisco, CA (H.E.W., A.D.); and Cardiovascular Research Institute, University of California, San Francisco (C.R.P., J.P.K., M.J.M.)
| | - H Ewa Witkowska
- From the Children's Hospital Oakland Research Institute, CA (V.S., A.W., J.B.S., L.N., J.A.B., G.W., T.M.F., R.O.R.); Department of Obstetrics, Gynecology and Reproductive Sciences, UCSF Sandler-Moore Mass Spectrometry Core Facility, San Francisco, CA (H.E.W., A.D.); and Cardiovascular Research Institute, University of California, San Francisco (C.R.P., J.P.K., M.J.M.)
| | - Andrew Dykstra
- From the Children's Hospital Oakland Research Institute, CA (V.S., A.W., J.B.S., L.N., J.A.B., G.W., T.M.F., R.O.R.); Department of Obstetrics, Gynecology and Reproductive Sciences, UCSF Sandler-Moore Mass Spectrometry Core Facility, San Francisco, CA (H.E.W., A.D.); and Cardiovascular Research Institute, University of California, San Francisco (C.R.P., J.P.K., M.J.M.)
| | - Jens B Simonsen
- From the Children's Hospital Oakland Research Institute, CA (V.S., A.W., J.B.S., L.N., J.A.B., G.W., T.M.F., R.O.R.); Department of Obstetrics, Gynecology and Reproductive Sciences, UCSF Sandler-Moore Mass Spectrometry Core Facility, San Francisco, CA (H.E.W., A.D.); and Cardiovascular Research Institute, University of California, San Francisco (C.R.P., J.P.K., M.J.M.)
| | - Lisa Nelbach
- From the Children's Hospital Oakland Research Institute, CA (V.S., A.W., J.B.S., L.N., J.A.B., G.W., T.M.F., R.O.R.); Department of Obstetrics, Gynecology and Reproductive Sciences, UCSF Sandler-Moore Mass Spectrometry Core Facility, San Francisco, CA (H.E.W., A.D.); and Cardiovascular Research Institute, University of California, San Francisco (C.R.P., J.P.K., M.J.M.)
| | - Jennifer A Beckstead
- From the Children's Hospital Oakland Research Institute, CA (V.S., A.W., J.B.S., L.N., J.A.B., G.W., T.M.F., R.O.R.); Department of Obstetrics, Gynecology and Reproductive Sciences, UCSF Sandler-Moore Mass Spectrometry Core Facility, San Francisco, CA (H.E.W., A.D.); and Cardiovascular Research Institute, University of California, San Francisco (C.R.P., J.P.K., M.J.M.)
| | - Clive R Pullinger
- From the Children's Hospital Oakland Research Institute, CA (V.S., A.W., J.B.S., L.N., J.A.B., G.W., T.M.F., R.O.R.); Department of Obstetrics, Gynecology and Reproductive Sciences, UCSF Sandler-Moore Mass Spectrometry Core Facility, San Francisco, CA (H.E.W., A.D.); and Cardiovascular Research Institute, University of California, San Francisco (C.R.P., J.P.K., M.J.M.)
| | - John P Kane
- From the Children's Hospital Oakland Research Institute, CA (V.S., A.W., J.B.S., L.N., J.A.B., G.W., T.M.F., R.O.R.); Department of Obstetrics, Gynecology and Reproductive Sciences, UCSF Sandler-Moore Mass Spectrometry Core Facility, San Francisco, CA (H.E.W., A.D.); and Cardiovascular Research Institute, University of California, San Francisco (C.R.P., J.P.K., M.J.M.)
| | - Mary J Malloy
- From the Children's Hospital Oakland Research Institute, CA (V.S., A.W., J.B.S., L.N., J.A.B., G.W., T.M.F., R.O.R.); Department of Obstetrics, Gynecology and Reproductive Sciences, UCSF Sandler-Moore Mass Spectrometry Core Facility, San Francisco, CA (H.E.W., A.D.); and Cardiovascular Research Institute, University of California, San Francisco (C.R.P., J.P.K., M.J.M.)
| | - Gordon Watson
- From the Children's Hospital Oakland Research Institute, CA (V.S., A.W., J.B.S., L.N., J.A.B., G.W., T.M.F., R.O.R.); Department of Obstetrics, Gynecology and Reproductive Sciences, UCSF Sandler-Moore Mass Spectrometry Core Facility, San Francisco, CA (H.E.W., A.D.); and Cardiovascular Research Institute, University of California, San Francisco (C.R.P., J.P.K., M.J.M.)
| | - Trudy M Forte
- From the Children's Hospital Oakland Research Institute, CA (V.S., A.W., J.B.S., L.N., J.A.B., G.W., T.M.F., R.O.R.); Department of Obstetrics, Gynecology and Reproductive Sciences, UCSF Sandler-Moore Mass Spectrometry Core Facility, San Francisco, CA (H.E.W., A.D.); and Cardiovascular Research Institute, University of California, San Francisco (C.R.P., J.P.K., M.J.M.)
| | - Robert O Ryan
- From the Children's Hospital Oakland Research Institute, CA (V.S., A.W., J.B.S., L.N., J.A.B., G.W., T.M.F., R.O.R.); Department of Obstetrics, Gynecology and Reproductive Sciences, UCSF Sandler-Moore Mass Spectrometry Core Facility, San Francisco, CA (H.E.W., A.D.); and Cardiovascular Research Institute, University of California, San Francisco (C.R.P., J.P.K., M.J.M.).
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Lefèvre M, Felmlee DJ, Parnot M, Baumert TF, Schuster C. Syndecan 4 is involved in mediating HCV entry through interaction with lipoviral particle-associated apolipoprotein E. PLoS One 2014; 9:e95550. [PMID: 24751902 PMCID: PMC3994096 DOI: 10.1371/journal.pone.0095550] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 03/28/2014] [Indexed: 12/16/2022] Open
Abstract
Hepatitis C virus (HCV) is a major cause of liver disease worldwide and HCV infection represents a major health problem. HCV associates with host lipoproteins forming host/viral hybrid complexes termed lipoviral particles. Apolipoprotein E (apoE) is a lipoprotein component that interacts with heparan sulfate proteoglycans (HSPG) to mediate hepatic lipoprotein uptake, and may likewise mediate HCV entry. We sought to define the functional regions of apoE with an aim to identify critical apoE binding partners involved in HCV infection. Using adenoviral vectors and siRNA to modulate apoE expression we show a direct correlation of apoE expression and HCV infectivity, whereas no correlation exists with viral protein expression. Mutating the HSPG binding domain (HSPG-BD) of apoE revealed key residues that are critical for mediating HCV infection. Furthermore, a novel synthetic peptide that mimics apoE’s HSPG-BD directly and competitively inhibits HCV infection. Genetic knockdown of the HSPG proteins syndecan (SDC) 1 and 4 revealed that SDC4 principally mediates HCV entry. Our data demonstrate that HCV uses apoE-SDC4 interactions to enter hepatoma cells and establish infection. Targeting apoE-SDC interactions could be an alternative strategy for blocking HCV entry, a critical step in maintaining chronic HCV infection.
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Affiliation(s)
- Mathieu Lefèvre
- Inserm, U1110, Research Institute on Viral and Hepatic Disease, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - Daniel J. Felmlee
- Inserm, U1110, Research Institute on Viral and Hepatic Disease, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - Marie Parnot
- Inserm, U1110, Research Institute on Viral and Hepatic Disease, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - Thomas F. Baumert
- Inserm, U1110, Research Institute on Viral and Hepatic Disease, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
- Pôle hépato-digestif, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Catherine Schuster
- Inserm, U1110, Research Institute on Viral and Hepatic Disease, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
- * E-mail:
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61
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Foley EM, Gordts PLSM, Stanford KI, Gonzales JC, Lawrence R, Stoddard N, Esko JD. Hepatic remnant lipoprotein clearance by heparan sulfate proteoglycans and low-density lipoprotein receptors depend on dietary conditions in mice. Arterioscler Thromb Vasc Biol 2013; 33:2065-74. [PMID: 23846497 DOI: 10.1161/atvbaha.113.301637] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Chylomicron and very low-density lipoprotein remnants are cleared from the circulation in the liver by heparan sulfate proteoglycan (HSPG) receptors (syndecan-1), the low-density lipoprotein receptor (LDLR), and LDLR-related protein-1 (LRP1), but the relative contribution of each class of receptors under different dietary conditions remains unclear. APPROACH AND RESULTS Triglyceride-rich lipoprotein clearance was measured in AlbCre(+)Ndst1(f/f), Ldlr(-/-), and AlbCre(+)Lrp1(f/f) mice and mice containing combinations of these mutations. Triglyceride measurements in single and double mutant mice showed that HSPGs and LDLR dominate clearance under fasting conditions and postprandial conditions, but LRP1 contributes significantly when LDLR is absent. Mice lacking hepatic expression of all 3 receptors (AlbCre(+)Ndst1(f/f) Lrp1(f/f) Ldlr(-/-)) displayed dramatic hyperlipidemia (870 ± 270 mg triglyceride/dL; 1300 ± 350 mg of total cholesterol/dL) and exhibited persistent elevated postprandial triglyceride levels because of reduced hepatic clearance. Analysis of the particles accumulating in mutants showed that HSPGs preferentially clear a subset of small triglyceride-rich lipoproteins (≈ 20-40 nm diameter), whereas LDLR and LRP1 clear larger particles (≈ 40-60 nm diameter). Finally, we show that HSPGs play a major role in clearance of triglyceride-rich lipoproteins in mice fed normal chow or under postprandial conditions but seem to play a less significant role on a high-fat diet. CONCLUSIONS These data show that HSPGs, LDLR, and LRP1 clear distinct subsets of particles, that HSPGs work independently of LDLR and LRP1, and that HSPGs, LDLR, and LRP1 are the 3 major hepatic triglyceride-rich lipoprotein clearance receptors in mice.
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Affiliation(s)
- Erin M Foley
- Department of Cellular and Molecular Medicine University of California San Diego, La Jolla, California, USA.,Department of Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California, USA
| | - Philip L S M Gordts
- Department of Cellular and Molecular Medicine University of California San Diego, La Jolla, California, USA
| | - Kristin I Stanford
- Department of Cellular and Molecular Medicine University of California San Diego, La Jolla, California, USA
| | - Jon C Gonzales
- Department of Cellular and Molecular Medicine University of California San Diego, La Jolla, California, USA.,Department of Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California, USA
| | - Roger Lawrence
- Department of Cellular and Molecular Medicine University of California San Diego, La Jolla, California, USA
| | - Nicole Stoddard
- Department of Cellular and Molecular Medicine University of California San Diego, La Jolla, California, USA.,Department of Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California, USA
| | - Jeffrey D Esko
- Department of Cellular and Molecular Medicine University of California San Diego, La Jolla, California, USA.,Department of Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California, USA
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