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Miranda Maravi JS, Leszczynski EC, Schwartz CS, Dev PK, Barber JL, Reasons RJ, Pearce RW, McPhaul MJ, Konrad RJ, Robbins JM, Gerszten RE, Collier TS, Bouchard C, Rohatgi A, Sarzynski MA. Associations of an HDL apolipoproteomic index with cardiometabolic risk factors before and after exercise training in the HERITAGE Family Study. Atherosclerosis 2024; 395:117587. [PMID: 38823353 DOI: 10.1016/j.atherosclerosis.2024.117587] [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: 11/15/2023] [Revised: 05/14/2024] [Accepted: 05/16/2024] [Indexed: 06/03/2024]
Abstract
BACKGROUND AND AIMS Previous studies have derived and validated an HDL apolipoproteomic score (pCAD) that predicts coronary artery disease (CAD) risk. However, the associations between pCAD and markers of cardiometabolic health in healthy adults are not known, nor are the effects of regular exercise on pCAD. METHODS A total of 641 physically inactive adults free of cardiovascular disease from the HERITAGE Family Study completed 20 weeks of exercise training. The pCAD index (range 0-100) was calculated using measurements of apolipoproteins A-I, C-I, C-II, C-III, and C-IV from ApoA-I-tagged serum (higher index = higher CAD risk). The associations between pCAD index and cardiometabolic traits at baseline and their training responses were assessed with Spearman correlation and general linear models. A Bonferroni correction of p < 8.9 × 10-04 was used to determine statistical significance. RESULTS The mean ± SD baseline pCAD index was 29 ± 32, with 106 (16.5 %) participants classified as high CAD risk. At baseline, pCAD index was positively associated with blood pressure, systemic inflammation, and body composition. HDL size, VO2max, and HDL-C were negatively associated with pCAD index at baseline. Of those classified as high CAD risk at baseline, 52 (49 %) were reclassified as normal risk after training. Following training, pCAD index changes were inversely correlated (p < 1.4 × 10-04) with changes in HDL-C, HDL size, and LDL size. CONCLUSIONS A higher pCAD index was associated with a worse cardiometabolic profile at baseline but improved with regular exercise. The results from this study highlight the potential role of HDL apolipoproteins as therapeutic targets for lifestyle interventions, particularly in high-risk individuals.
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Affiliation(s)
| | - Eric C Leszczynski
- Department of Exercise Science, University of South Carolina, Columbia, SC, USA
| | - Charles S Schwartz
- Department of Exercise Science, University of South Carolina, Columbia, SC, USA
| | - Prasun K Dev
- Department of Exercise Science, University of South Carolina, Columbia, SC, USA
| | - Jacob L Barber
- CardioVascular Institute, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Riley J Reasons
- Department of Exercise Science, University of South Carolina, Columbia, SC, USA
| | - Ryan W Pearce
- Quest Diagnostics Cardiometabolic Center of Excellence at Cleveland HeartLab, Cleveland, OH, USA
| | - Michael J McPhaul
- Quest Diagnostics Cardiometabolic Center of Excellence at Cleveland HeartLab, Cleveland, OH, USA
| | - Robert J Konrad
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Jeremy M Robbins
- CardioVascular Institute, Beth Israel Deaconess Medical Center, Boston, MA, USA; Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Robert E Gerszten
- CardioVascular Institute, Beth Israel Deaconess Medical Center, Boston, MA, USA; Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Timothy S Collier
- Quest Diagnostics Cardiometabolic Center of Excellence at Cleveland HeartLab, Cleveland, OH, USA
| | - Claude Bouchard
- Human Genomics Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - Anand Rohatgi
- Division of Cardiology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Mark A Sarzynski
- Department of Exercise Science, University of South Carolina, Columbia, SC, USA.
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2
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Fu L, Guldiken N, Remih K, Karl AS, Preisinger C, Strnad P. Serum/Plasma Proteome in Non-Malignant Liver Disease. Int J Mol Sci 2024; 25:2008. [PMID: 38396688 PMCID: PMC10889128 DOI: 10.3390/ijms25042008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/31/2024] [Accepted: 02/03/2024] [Indexed: 02/25/2024] Open
Abstract
The liver is the central metabolic organ and produces 85-90% of the proteins found in plasma. Accordingly, the plasma proteome is an attractive source of liver disease biomarkers that reflects the different cell types present in this organ, as well as the processes such as responses to acute and chronic injury or the formation of an extracellular matrix. In the first part, we summarize the biomarkers routinely used in clinical evaluations and their biological relevance in the different stages of non-malignant liver disease. Later, we describe the current proteomic approaches, including mass spectrometry and affinity-based techniques, that allow a more comprehensive assessment of the liver function but also require complex data processing. The many approaches of analysis and interpretation and their potential caveats are delineated. While these advances hold the promise to transform our understanding of liver diseases and support the development and validation of new liver-related drugs, an interdisciplinary collaboration is needed.
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Affiliation(s)
- Lei Fu
- Department of Internal Medicine III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074 Aachen, Germany; (L.F.); (N.G.); (K.R.); (A.S.K.)
| | - Nurdan Guldiken
- Department of Internal Medicine III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074 Aachen, Germany; (L.F.); (N.G.); (K.R.); (A.S.K.)
| | - Katharina Remih
- Department of Internal Medicine III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074 Aachen, Germany; (L.F.); (N.G.); (K.R.); (A.S.K.)
| | - Anna Sophie Karl
- Department of Internal Medicine III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074 Aachen, Germany; (L.F.); (N.G.); (K.R.); (A.S.K.)
| | - Christian Preisinger
- Proteomics Facility, Interdisciplinary Centre for Clinical Research (IZKF), Medical School, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany;
| | - Pavel Strnad
- Department of Internal Medicine III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074 Aachen, Germany; (L.F.); (N.G.); (K.R.); (A.S.K.)
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3
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Almeida FC, Patra K, Giannisis A, Niesnerova A, Nandakumar R, Ellis E, Oliveira TG, Nielsen HM. APOE genotype dictates lipidomic signatures in primary human hepatocytes. J Lipid Res 2024; 65:100498. [PMID: 38216055 PMCID: PMC10875595 DOI: 10.1016/j.jlr.2024.100498] [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: 10/17/2023] [Revised: 12/27/2023] [Accepted: 01/09/2024] [Indexed: 01/14/2024] Open
Abstract
Apolipoprotein E (APOE) genetic variants are most notably known for their divergent impact on the risk of developing Alzheimer's disease. While APOE genotype has been consistently shown to modulate lipid metabolism in a variety of cellular contexts, the effect of APOE alleles on the lipidome in hepatocytes is unknown. In this study, we investigated the contribution of APOE alleles to lipidomic profiles of donor-derived primary human hepatocytes from 77 subjects. Lipidomic data obtained by liquid chromatography-mass spectrometry were analyzed across ε2/ε3, ε3/ε3, and ε3/ε4 genotypes to reveal how APOE modulates lipid relative levels over age and between groups. Hepatic APOE concentration, measured by ELISA, was assessed for correlation with lipid abundance in subjects grouped as per APOE genotype and sex. APOE genotype-specific differential lipidomic signatures associated with age for multiple lipid classes but did not differ between sexes. Compared to ε2/ε3, ε3/ε4 hepatocytes had higher abundance of acylcarnitines (AC) and acylphosphatidylglycerol (AcylPG) as a class, as well as higher medium and long-chain ACs, AcylPG, phosphatidylglycerol (PG), bis(monoacylglycerol)phosphate (BMP), monoacylglycerol (MG) and diacylglycerol (DG) species. The ε3/ε4 hepatocytes also exhibited a higher abundance of medium and long-chain ACs compared to the ε3/ε3 hepatocytes. Only in the ε3/ε4 hepatocytes, APOE concentration was lower and showed a negative correlation with BMP levels, specifically in females. APOE genotype dictates a differential lipidome in primary human hepatocytes. The lipids involved suggest mitochondrial dysfunction with accompanying alterations in neutral lipid storage, reflective of a general disturbance of free fatty acid metabolism in human hepatocytes with the ε4 allele.
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Affiliation(s)
- Francisco C Almeida
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal; Department of Neuroradiology, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Kalicharan Patra
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Andreas Giannisis
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Anezka Niesnerova
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Renu Nandakumar
- Irving Institute for Clinical and Translational Research, Columbia University Irving Medical Center, New York, USA
| | - Ewa Ellis
- Department of Clinical Science, Intervention and Technology, (CLINTEC), Division of Transplantation surgery, Karolinska Institutet and ME Transplantation, Karolinska University Hospital, Huddinge, Sweden
| | - Tiago Gil Oliveira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal; Department of Neuroradiology, Hospital de Braga, Braga, Portugal.
| | - Henrietta M Nielsen
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
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4
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Frudd K, Sivaprasad S, Raman R, Krishnakumar S, Revathy YR, Turowski P. Diagnostic circulating biomarkers to detect vision-threatening diabetic retinopathy: Potential screening tool of the future? Acta Ophthalmol 2022; 100:e648-e668. [PMID: 34269526 DOI: 10.1111/aos.14954] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 06/02/2021] [Accepted: 06/17/2021] [Indexed: 12/12/2022]
Abstract
With the increasing prevalence of diabetes in developing and developed countries, the socio-economic burden of diabetic retinopathy (DR), the leading complication of diabetes, is growing. Diabetic retinopathy (DR) is currently one of the leading causes of blindness in working-age adults worldwide. Robust methodologies exist to detect and monitor DR; however, these rely on specialist imaging techniques and qualified practitioners. This makes detecting and monitoring DR expensive and time-consuming, which is particularly problematic in developing countries where many patients will be remote and have little contact with specialist medical centres. Diabetic retinopathy (DR) is largely asymptomatic until late in the pathology. Therefore, early identification and stratification of vision-threatening DR (VTDR) is highly desirable and will ameliorate the global impact of this disease. A simple, reliable and more cost-effective test would greatly assist in decreasing the burden of DR around the world. Here, we evaluate and review data on circulating protein biomarkers, which have been verified in the context of DR. We also discuss the challenges and developments necessary to translate these promising data into clinically useful assays, to detect VTDR, and their potential integration into simple point-of-care testing devices.
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Affiliation(s)
- Karen Frudd
- Institute of Ophthalmology University College London London UK
| | - Sobha Sivaprasad
- Institute of Ophthalmology University College London London UK
- NIHR Moorfields Biomedical Research Centre Moorfields Eye Hospital London UK
| | - Rajiv Raman
- Vision Research Foundation Sankara Nethralaya Chennai Tamil Nadu India
| | | | | | - Patric Turowski
- Institute of Ophthalmology University College London London UK
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5
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Di L, Maiseyeu A. Low-density lipoprotein nanomedicines: mechanisms of targeting, biology, and theranostic potential. Drug Deliv 2021; 28:408-421. [PMID: 33594923 PMCID: PMC7894439 DOI: 10.1080/10717544.2021.1886199] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Native nanostructured lipoproteins such as low- and high-density lipoproteins (LDL and HDL) are powerful tools for the targeted delivery of drugs and imaging agents. While the cellular recognition of well-known HDL-based carriers occurs via interactions with an HDL receptor, the selective delivery and uptake of LDL particles by target cells are more complex. The most well-known mode of LDL-based delivery is via the interaction between apolipoprotein B (Apo-B) - the main protein of LDL - and the low-density lipoprotein receptor (LDLR). LDLR is expressed in the liver, adipocytes, and macrophages, and thus selectively delivers LDL carriers to these cells and tissues. Moreover, the elevated expression of LDLR in tumor cells indicates a role for LDL in the targeted delivery of chemotherapy drugs. In addition, chronic inflammation associated with hypercholesterolemia (i.e., high levels of endogenous LDL) can be abated by LDL carriers, which outcompete the deleterious oxidized LDL for uptake by macrophages. In this case, synthetic LDL nanocarriers act as 'eat-me' signals and exploit mechanisms of native LDL uptake for targeted drug delivery and imaging. Lastly, recent studies have shown that the delivery of LDL-based nanocarriers to macrophages via fluid-phase pinocytosis is a promising tool for atherosclerosis imaging. Hence, the present review summarizes the use of natural and synthetic LDL-based carriers for drug delivery and imaging and discusses various mechanisms of targeting.
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Affiliation(s)
- Lin Di
- Cardiovascular Research Institute, School of Medicine, Case Western Reserve University, Clevehand, OH, USA
| | - Andrei Maiseyeu
- Cardiovascular Research Institute, School of Medicine, Case Western Reserve University, Clevehand, OH, USA
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6
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Shimotohno K. HCV Assembly and Egress via Modifications in Host Lipid Metabolic Systems. Cold Spring Harb Perspect Med 2021; 11:cshperspect.a036814. [PMID: 32122916 PMCID: PMC7778218 DOI: 10.1101/cshperspect.a036814] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Hepatitis C virus (HCV) proliferates by hijacking the host lipid machinery. In vitro replication systems revealed many aspects of the virus life cycle; in particular, viral utilization of host lipid metabolism during HCV proliferation. HCV interacts with lipid droplets (LDs) before starting the process of virus capsid formation at the lipid-rich endoplasmic reticulum (ER) membrane compartment. HCV buds into the ER via lipoprotein assembly and secretion. Exchangeable apolipoproteins, represented by apolipoprotein E (apoE), play pivotal roles in enhancing HCV-specific infectivity. HCV virions are likely to interact with other lipoproteins circulating in blood vessels and incorporate apolipoproteins as well as lipids. This review focuses on virus assembly and egress by briefly describing the recent advances in this area.
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7
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Ji M, Xu K, Zhang D, Chen T, Shen L, Wu W, Zhang J. Adipose-Tissue-Specific Expression of Pig ApoR Protects Mice from Diet-Induced Obesity. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:2256-2262. [PMID: 31927923 DOI: 10.1021/acs.jafc.9b06995] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Fat deposition is one of the most important economic traits of pigs. Decreasing the subcutaneous fat and increasing the intramuscular fat are believed to be an effective way to improve pork quality, which is one of the main goals of pig breeding. Identifying key genes that control porcine lipid metabolism is essential for achieving this goal. Apolipoprotein R (apoR) was identified as the crucial molecule in the process of pig adipose reduction by clenbuterol. In this study, transgenic mice with adipose-tissue-specific overexpression of pig apoR (apoR mice) were constructed. The apoR mice gained less weight than wild-type (WT) mice after 18 weeks of feeding a high-fat diet. A comparison of organs between the two genotypes revealed that the weight of white adipose tissue, including inguinal and epididymal fat tissue, was significantly decreased and the weight of liver tissue was increased in apoR mice compared with WT mice. Glucose and insulin intolerance tests showed that the glucose metabolism of apoR mice was similar to that of WT mice. Histological staining proved that the adipocytes of apoR mice had a reduced average size, and gene expression analysis indicated that lipolysis in the adipose tissue of apoR mice was enhanced. Finally, the primary culture of inguinal adipocytes revealed that apoR promotes lipolysis via the Erk1/2 pathway. Taken together, the results indicate that adipose-tissue-specific expression of pig apoR protects mice from diet-induced obesity by enhancing lipolysis.
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Affiliation(s)
- Miao Ji
- College of Biological, Chemical Sciences and Engineering , Jiaxing University , Jiaxing 314001 , China
- College of Agronomy and Biotechnology , Hebei Normal University of Science and Technology , Qinhuangdao 066000 , China
| | - Ke Xu
- College of Biological, Chemical Sciences and Engineering , Jiaxing University , Jiaxing 314001 , China
- College of Agronomy and Biotechnology , Hebei Normal University of Science and Technology , Qinhuangdao 066000 , China
| | - Dawei Zhang
- College of Biological, Chemical Sciences and Engineering , Jiaxing University , Jiaxing 314001 , China
| | - Tingting Chen
- Jiaxing Maternal and Child Health Care Hospital , Jiaxing 314001 , China
| | - Liangcai Shen
- College of Agronomy and Biotechnology , Hebei Normal University of Science and Technology , Qinhuangdao 066000 , China
| | - Wenjing Wu
- College of Biological, Chemical Sciences and Engineering , Jiaxing University , Jiaxing 314001 , China
| | - Jin Zhang
- College of Biological, Chemical Sciences and Engineering , Jiaxing University , Jiaxing 314001 , China
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8
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Koubaa-Ghorbel F, Chaâbane M, Turki M, Makni-Ayadi F, El Feki A. The protective effects of Salvia officinalis essential oil compared to simvastatin against hyperlipidemia, liver, and kidney injuries in mice submitted to a high-fat diet. J Food Biochem 2020; 44:e13160. [PMID: 32010989 DOI: 10.1111/jfbc.13160] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 01/12/2020] [Accepted: 01/15/2020] [Indexed: 12/11/2022]
Abstract
The present study was undertaken to evaluate the effects of Salvia officinalis essential oil (SEO) and simvastatin in hyperlipidemic mice. Animals were randomly divided into four groups. The control group received a standard diet. The high-fat diet (HFD) group received HFD. The third and fourth groups received HFD associated either with simvastatin (2.5 mg/kg bw) or with SEO (4 mg/kg bw). All animals were sacrificed after 8 weeks of treatment. SEO and simvastatin reduced in HFD mice body weight gain, hyperlipidemia, disruption of liver and renal functions and reactive oxygen species production. In fact, total cholesterol, triglycerides, total lipids, and low-density lipoprotein cholesterol levels, as well as aspartate transaminase, alanine transaminase, gamma-glutamyltranspeptidase and lactate dehydrogenase activities were reduced, while fecal lipids increased compared to those of HFD mice. The lipid-lowering effect of SEO was more effective than that of simvastatin. PRACTICAL APPLICATIONS: High-fat diet provokes hyperlipidemia, atherosclerosis, and abnormal lipid metabolism leading to the development of hepatic and renal dysfunctions as well as perturbations of the antioxidant status in liver and kidney. The results of this research highlight the beneficial effects of SEO in the management of these disorders without inducing side effects; in fact, the plant essential oil decreased lipids and improved the antioxidant status more than did a synthetic drug.
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Affiliation(s)
- Fatma Koubaa-Ghorbel
- Animal Ecophysiology Laboratory, Sciences Faculty, University of Sfax, Sfax, Tunisia
| | - Mariem Chaâbane
- Unit of Enzymes and Bioconversion, National Engineering School, University of Sfax, Sfax, Tunisia
| | - Mouna Turki
- Biochemistry Laboratory, CHU H. Bourguiba, University of Sfax, Sfax, Tunisia
| | - Fatma Makni-Ayadi
- Biochemistry Laboratory, CHU H. Bourguiba, University of Sfax, Sfax, Tunisia
| | - Abdelfattah El Feki
- Animal Ecophysiology Laboratory, Sciences Faculty, University of Sfax, Sfax, Tunisia
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9
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The Exchangeable Apolipoprotein Nplp2 Sustains Lipid Flow and Heat Acclimation in Drosophila. Cell Rep 2019; 27:886-899.e6. [DOI: 10.1016/j.celrep.2019.03.074] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 02/11/2019] [Accepted: 03/19/2019] [Indexed: 11/24/2022] Open
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10
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Sołtysik K, Ohsaki Y, Tatematsu T, Cheng J, Fujimoto T. Nuclear lipid droplets derive from a lipoprotein precursor and regulate phosphatidylcholine synthesis. Nat Commun 2019; 10:473. [PMID: 30692541 PMCID: PMC6349838 DOI: 10.1038/s41467-019-08411-x] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 01/10/2019] [Indexed: 02/07/2023] Open
Abstract
The origin and physiological significance of lipid droplets (LDs) in the nucleus is not clear. Here we show that nuclear LDs in hepatocytes are derived from apolipoprotein B (ApoB)-free lumenal LDs, a precursor to very low-density lipoproprotein (VLDL) generated in the ER lumen by microsomal triglyceride transfer protein. ApoB-free lumenal LDs accumulate under ER stress, grow within the lumen of the type I nucleoplasmic reticulum, and turn into nucleoplasmic LDs by disintegration of the surrounding inner nuclear membrane. Oleic acid with or without tunicamycin significantly increases the formation of nucleoplasmic LDs, to which CTP:phosphocholine cytidylyltransferase α (CCTα) is recruited, resulting in activation of phosphatidylcholine (PC) synthesis. Perilipin-3 competes with CCTα in binding to nucleoplasmic LDs, and thus, knockdown and overexpression of perilipin-3 increases and decreases PC synthesis, respectively. The results indicate that nucleoplasmic LDs in hepatocytes constitute a feedback mechanism to regulate PC synthesis in accordance with ER stress. The origin and physiological significance of lipid droplets (LDs) in the nucleus is not clear. Here authors show that nucleoplasmic LDs in hepatocytes are derived from apolipoprotein B (ApoB)-free lumenal LDs and constitute a feedback mechanism to regulate PC synthesis in accordance with ER stress.
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Affiliation(s)
- Kamil Sołtysik
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Yuki Ohsaki
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan.
| | - Tsuyako Tatematsu
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Jinglei Cheng
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Toyoshi Fujimoto
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan.
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11
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Zhang H, Qiao L, Luo G. Characterization of apolipoprotein C1 in hepatitis C virus infection and morphogenesis. Virology 2018; 524:1-9. [PMID: 30130702 DOI: 10.1016/j.virol.2018.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/05/2018] [Accepted: 08/05/2018] [Indexed: 12/12/2022]
Abstract
Previous studies have shown that apolipoprotein C1 (apoC1)-specific antibodies precipitated hepatitis C virus (HCV) and neutralized HCV infectivity, suggesting that apoC1 is a HCV component. However, the importance of apoC1 in the HCV life cycle has not been experimentally examined. In the present study, we sought to determine the role of apoC1 in the HCV infection and morphogenesis by knocking out the apoC1 gene using the CRISPR/Cas9 system. Strikingly, apoC1 gene knockout markedly enhanced apoE expression. As a result, apoC1 gene knockout per se didn't significantly affect HCV infection or morphogenesis, probably ascribing to its redundant functions with apoE. However, knockout of apoC1 gene potentiated the impairment of HCV infection and/or morphogenesis by apoE-specific small interfering RNAs. Additionally, a recombinant apoC1 protein efficiently blocked HCV infection. Collectively, these findings suggest that apoC1 and apoE have redundant functions in the HCV infection and morphogenesis.
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Affiliation(s)
- Han Zhang
- Department of Microbiology, Peking University School of Basic Medical Sciences, Beijing 100191, China
| | - Luhua Qiao
- Department of Microbiology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, United States
| | - Guangxiang Luo
- Department of Microbiology, Peking University School of Basic Medical Sciences, Beijing 100191, China; Department of Microbiology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, United States.
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12
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Wrensch F, Crouchet E, Ligat G, Zeisel MB, Keck ZY, Foung SKH, Schuster C, Baumert TF. Hepatitis C Virus (HCV)-Apolipoprotein Interactions and Immune Evasion and Their Impact on HCV Vaccine Design. Front Immunol 2018; 9:1436. [PMID: 29977246 PMCID: PMC6021501 DOI: 10.3389/fimmu.2018.01436] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/11/2018] [Indexed: 12/15/2022] Open
Abstract
With more than 71 million people chronically infected, hepatitis C virus (HCV) is one of the leading causes of liver disease and hepatocellular carcinoma. While efficient antiviral therapies have entered clinical standard of care, the development of a protective vaccine is still elusive. Recent studies have shown that the HCV life cycle is closely linked to lipid metabolism. HCV virions associate with hepatocyte-derived lipoproteins to form infectious hybrid particles that have been termed lipo-viro-particles. The close association with lipoproteins is not only critical for virus entry and assembly but also plays an important role during viral pathogenesis and for viral evasion from neutralizing antibodies. In this review, we summarize recent findings on the functional role of apolipoproteins for HCV entry and assembly. Furthermore, we highlight the impact of HCV-apolipoprotein interactions for evasion from neutralizing antibodies and discuss the consequences for antiviral therapy and vaccine design. Understanding these interactions offers novel strategies for the development of an urgently needed protective vaccine.
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Affiliation(s)
- Florian Wrensch
- INSERM, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France.,Université de Strasbourg, Strasbourg, France
| | - Emilie Crouchet
- INSERM, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France.,Université de Strasbourg, Strasbourg, France
| | - Gaetan Ligat
- INSERM, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France.,Université de Strasbourg, Strasbourg, France
| | - Mirjam B Zeisel
- INSERM, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France.,Université de Strasbourg, Strasbourg, France.,INSERM U1052, CNRS UMR 5286, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL), Lyon, France
| | - Zhen-Yong Keck
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, United States
| | - Steven K H Foung
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, United States
| | - Catherine Schuster
- INSERM, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France.,Université de Strasbourg, Strasbourg, France
| | - Thomas F Baumert
- INSERM, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France.,Université de Strasbourg, Strasbourg, France.,Institut Hospitalo-Universitaire, Pôle Hépato-digestif, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.,Institut Universitaire de France, Paris, France
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13
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Takacs CN, Andreo U, Dao Thi VL, Wu X, Gleason CE, Itano MS, Spitz-Becker GS, Belote RL, Hedin BR, Scull MA, Rice CM, Simon SM. Differential Regulation of Lipoprotein and Hepatitis C Virus Secretion by Rab1b. Cell Rep 2018; 21:431-441. [PMID: 29020629 DOI: 10.1016/j.celrep.2017.09.053] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 08/07/2017] [Accepted: 09/15/2017] [Indexed: 12/11/2022] Open
Abstract
Secretory cells produce diverse cargoes, yet how they regulate concomitant secretory traffic remains insufficiently explored. Rab GTPases control intracellular vesicular transport. To map secretion pathways, we generated a library of lentivirus-expressed dominant-negative Rab mutants and used it in a large-scale screen to identify regulators of hepatic lipoprotein secretion. We identified several candidate pathways, including those mediated by Rab11 and Rab8. Surprisingly, inhibition of Rab1b, the major regulator of transport from the endoplasmic reticulum to the Golgi, differently affected the secretion of the very-low-density lipoprotein components ApoE and ApoB100, despite their final association on mature secreted lipoprotein particles. Since hepatitis C virus (HCV) incorporates ApoE and ApoB100 into its virus particle, we also investigated infectious HCV secretion and show that its regulation by Rab1b mirrors that of ApoB100. These observations reveal differential regulation of hepatocyte secretion by Rab1b and advance our understanding of lipoprotein assembly and lipoprotein and HCV secretion.
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Affiliation(s)
- Constantin N Takacs
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, NY 10065, USA; Laboratory of Virology and Infectious Disease and Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA
| | - Ursula Andreo
- Laboratory of Virology and Infectious Disease and Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA
| | - Viet Loan Dao Thi
- Laboratory of Virology and Infectious Disease and Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA
| | - Xianfang Wu
- Laboratory of Virology and Infectious Disease and Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA
| | - Caroline E Gleason
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Michelle S Itano
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | | | - Rachel L Belote
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Brenna R Hedin
- Laboratory of Virology and Infectious Disease and Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA
| | - Margaret A Scull
- Laboratory of Virology and Infectious Disease and Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease and Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA
| | - Sanford M Simon
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, NY 10065, USA.
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Sirwi A, Hussain MM. Lipid transfer proteins in the assembly of apoB-containing lipoproteins. J Lipid Res 2018; 59:1094-1102. [PMID: 29650752 DOI: 10.1194/jlr.r083451] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 04/12/2018] [Indexed: 11/20/2022] Open
Abstract
A better understanding of intracellular lipoprotein assembly may help identify proteins with important roles in lipid disorders. apoB-containing lipoproteins (B-lps) are macromolecular lipid and protein micelles that act as specialized transport vehicles for hydrophobic lipids. They are assembled predominantly in enterocytes and hepatocytes to transport dietary and endogenous fat, respectively, to different tissues. Assembly occurs in the endoplasmic reticulum (ER) and is dependent on lipid resynthesis in the ER and on a chaperone, namely, microsomal triglyceride transfer protein (MTTP). Precursors for lipid synthesis are obtained from extracellular sources and from cytoplasmic lipid droplets. MTTP is the major and essential lipid transfer protein that transfers phospholipids and triacylglycerols to nascent apoB for the assembly of lipoproteins. Assembly is aided by cell death-inducing DFF45-like effector B and by phospholipid transfer protein, which may facilitate additional deposition of triacylglycerols and phospholipids, respectively, to apoB. Here, we summarize the current understanding of the different steps in the assembly of B-lps and discuss the role of lipid transfer proteins in these steps to help identify new clinical targets for lipid-associated disorders, such as heart disease.
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Affiliation(s)
- Alaa Sirwi
- School of Graduate Studies, Molecular and Cell Biology Program, State University of New York Downstate Medical Center, Brooklyn, NY
| | - M Mahmood Hussain
- New York University Winthrop Hospital, Mineola, NY and Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY
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15
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Zannis VI, Su S, Fotakis P. Role of apolipoproteins, ABCA1 and LCAT in the biogenesis of normal and aberrant high density lipoproteins. J Biomed Res 2017; 31:471. [PMID: 29109329 PMCID: PMC6307667 DOI: 10.7555/jbr.31.20160082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 08/30/2016] [Indexed: 12/28/2022] Open
Abstract
In this review, we focus on the pathway of biogenesis of HDL, the essential role of apoA-I, ATP binding cassette transporter A1 (ABCA1), and lecithin: cholesterol acyltransferase (LCAT) in the formation of plasma HDL; the generation of aberrant forms of HDL containing mutant apoA-I forms and the role of apoA-IV and apoE in the formation of distinct HDL subpopulations. The biogenesis of HDL requires functional interactions of the ABCA1 with apoA-I (and to a lesser extent with apoE and apoA-IV) and subsequent interactions of the nascent HDL species thus formed with LCAT. Mutations in apoA-I, ABCA1 and LCAT either prevent or impair the formation of HDL and may also affect the functionality of the HDL species formed. Emphasis is placed on three categories of apoA-I mutations. The first category describes a unique bio-engineered apoA-I mutation that disrupts interactions between apoA-I and ABCA1 and generates aberrant preβ HDL subpopulations that cannot be converted efficiently to α subpopulations by LCAT. The second category describes natural and bio-engineered apoA-I mutations that generate preβ and small size α4 HDL subpopulations, and are associated with low plasma HDL levels. These phenotypes can be corrected by excess LCAT. The third category describes bio-engineered apoA-I mutations that induce hypertriglyceridemia that can be corrected by excess lipoprotein lipase and also have defective maturation of HDL. The HDL phenotypes described here may serve in the future for diagnosis, prognoses and potential treatment of abnormalities that affect the biogenesis and functionality of HDL.
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Affiliation(s)
- Vassilis I. Zannis
- . Molecular Genetics, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118, USA
- . Department University of Crete, School of Medicine, Heraklion, Crete, Greece
| | - Shi Su
- . Molecular Genetics, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118, USA
| | - Panagiotis Fotakis
- . Molecular Genetics, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118, USA
- . Department University of Crete, School of Medicine, Heraklion, Crete, Greece
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16
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Extracellular Interactions between Hepatitis C Virus and Secreted Apolipoprotein E. J Virol 2017; 91:JVI.02227-16. [PMID: 28539442 DOI: 10.1128/jvi.02227-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 05/04/2017] [Indexed: 12/12/2022] Open
Abstract
Interactions between hepatitis C virus (HCV) and lipoproteins in humans play an important role in the efficient establishment of chronic infection. Apolipoprotein E (ApoE) on the HCV envelope mediates virus attachment to host cells as well as immune evasion. This interaction is thought to occur in hepatocytes, as ApoE plays dual functions in HCV assembly and maturation as well as cell attachment. In the present study, we found that secreted ApoE (sApoE) can also bind to viral particles via its C-terminal domain after HCV is released from the cell. Furthermore, the binding affinity of interactions between the sApoE N terminus and cell surface receptors affected HCV infectivity in a dose-dependent manner. The extracellular binding of sApoE to HCV is dependent on HCV envelope proteins, and recombinant HCV envelope proteins are also able to bind to sApoE. These results suggest that extracellular interactions between HCV and sApoE may potentially complicate vaccine development and studies of viral pathogenesis.IMPORTANCE End-stage liver disease caused by chronic HCV infection remains a clinical challenge, and there is an urgent need for a prophylactic method of controlling HCV infection. Because host immunity against HCV is poorly understood, additional investigations of host-virus interactions in the context of HCV are important. HCV is primarily transmitted through blood, which is rich in lipoproteins. Therefore, it is of interest to further determine how HCV interacts with lipoproteins in human blood. In this study, we found that secreted ApoE (sApoE), an exchangeable component found in lipoproteins, participates in extracellular interactions with HCV virions. More significantly, different variants of sApoE differentially affect HCV infection efficiency in a dose-dependent manner. These findings provide greater insight into HCV infection and host immunity and could help propel the development of new strategies for preventing HCV infection.
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17
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Crouchet E, Baumert TF, Schuster C. Hepatitis C virus-apolipoprotein interactions: molecular mechanisms and clinical impact. Expert Rev Proteomics 2017; 14:593-606. [PMID: 28625086 PMCID: PMC6138823 DOI: 10.1080/14789450.2017.1344102] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Chronic hepatitis C virus (HCV) infection is a leading cause of cirrhosis, hepatocellular carcinoma and liver failure. Moreover, chronic HCV infection is associated with liver steatosis and metabolic disorders. With 130-150 million people chronically infected in the world, HCV infection represents a major public health problem. One hallmark on the virus is its close link with hepatic lipid and lipoprotein metabolism. Areas covered: HCV is associated with lipoprotein components such as apolipoproteins. These interactions play a key role in the viral life cycle, viral persistence and pathogenesis of liver disease. This review introduces first the role of apolipoproteins in lipoprotein metabolism, then highlights the molecular mechanisms of HCV-lipoprotein interactions and finally discusses their clinical impact. Expert commentary: While the study of virus-host interactions has resulted in a improvement of the understanding of the viral life cycle and the development of highly efficient therapies, major challenges remain: access to therapy is limited and an urgently needed HCV vaccine remains still elusive. Furthermore, the pathogenesis of disease biology is still only partially understood. The investigation of HCV-lipoproteins interactions offers new perspectives for novel therapeutic approaches, contribute to HCV vaccine design and understand virus-induced liver disease and cancer.
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Affiliation(s)
- Emilie Crouchet
- Inserm, U1110: Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - Thomas F. Baumert
- Inserm, U1110: Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
- Pôle hépato-digestif, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Catherine Schuster
- Inserm, U1110: Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
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18
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Crouchet E, Lefèvre M, Verrier ER, Oudot MA, Baumert TF, Schuster C. Extracellular lipid-free apolipoprotein E inhibits HCV replication and induces ABCG1-dependent cholesterol efflux. Gut 2017; 66:896-907. [PMID: 27609828 PMCID: PMC5531222 DOI: 10.1136/gutjnl-2015-311289] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 07/13/2016] [Accepted: 07/30/2016] [Indexed: 12/21/2022]
Abstract
OBJECTIVE The HCV life cycle and the lipid metabolism are inextricably intertwined. In the blood, HCV virions are associated with lipoproteins, forming lipoviroparticles (LVPs), which are the most infectious form of the virus. Apolipoprotein E (apoE), a key LVP component, plays an essential role in HCV entry, assembly and egress. ApoE is also a cell host factor involved in lipoprotein homeostasis. Although the majority of apoE is associated with lipoproteins, a lipid-free (LF) form exists in blood. However, the role of LF-apoE in both lipid metabolism and HCV life cycle is poorly understood. DESIGN In this study, using the cell culture-derived HCV model system in human hepatoma Huh7.5.1 cells and primary human hepatocytes (PHH), we investigated the effect of LF-apoE on the early steps of HCV life cycle and on the lipid metabolism of hepatic cells. RESULTS A dose-dependent decrease in HCV replication was observed when Huh7.5.1 cells and PHH were treated with increasing amounts of LF-apoE. We showed that LF-apoE acts on HCV replication independently of previously described apoE receptors. We observed that LF-apoE induced a marked hepatic cholesterol efflux via the ATP-binding cassette subfamily G member 1 (ABCG1) protein that in turn inhibits HCV replication. LF-apoE also increases both apolipoprotein AI and high-density lipoprotein production. CONCLUSIONS Our findings highlight a new mechanism in lipid metabolism regulation and interaction of the lipid metabolism with the HCV life cycle, which may be important for viral pathogenesis and might also be explored for antiviral therapy.
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Affiliation(s)
- Emilie Crouchet
- INSERM, UMR_S1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France,Université de Strasbourg, Strasbourg, France
| | - Mathieu Lefèvre
- INSERM, UMR_S1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France,Université de Strasbourg, Strasbourg, France
| | - Eloi R Verrier
- INSERM, UMR_S1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France,Université de Strasbourg, Strasbourg, France
| | - Marine A Oudot
- INSERM, UMR_S1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France,Université de Strasbourg, Strasbourg, France
| | - Thomas F Baumert
- INSERM, UMR_S1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France,Université de Strasbourg, Strasbourg, France,Institut Hopitalo-Universitaire, Pôle hépato-digestif, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Catherine Schuster
- INSERM, UMR_S1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France,Université de Strasbourg, Strasbourg, France
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19
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Neglected but Important Role of Apolipoprotein E Exchange in Hepatitis C Virus Infection. J Virol 2016; 90:9632-9643. [PMID: 27535051 DOI: 10.1128/jvi.01353-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 08/03/2016] [Indexed: 12/22/2022] Open
Abstract
Hepatitis C virus (HCV) is a major cause of chronic liver disease, infecting approximately 170 million people worldwide. HCV assembly is tightly associated with the lipoprotein pathway. Exchangeable apolipoprotein E (apoE) is incorporated on infectious HCV virions and is important for infectious HCV virion morphogenesis and entry. Moreover, the virion apoE level is positively correlated with its ability to escape E2 antibody neutralization. However, the role of apoE exchange in the HCV life cycle is unclear. In this study, the relationship between apoE expression and cell permissiveness to HCV infection was assessed by infecting apoE knockdown and derived apoE rescue cell lines with HCV. Exchange of apoE between lipoproteins and HCV lipoviral particles (LVPs) was evaluated by immunoprecipitation, infectivity testing, and viral genome quantification. Cell and heparin column binding assays were applied to determine the attachment efficiency of LVPs with different levels of incorporated apoE. The results showed that cell permissiveness for HCV infection was determined by exogenous apoE-associated lipoproteins. Furthermore, apoE exchange did occur between HCV LVPs and lipoproteins, which was important to maintain a high apoE level on LVPs. Lipid-free apoE was capable of enhancing HCV infectivity for apoE knockdown cells but not apoE rescue cells. A higher apoE level on LVPs conferred more efficient LVP attachment to both the cell surface and heparin beads. This study revealed that exogenous apoE-incorporating lipoproteins from uninfected hepatocytes safeguarded the apoE level of LVPs for more efficient attachment during HCV infection. IMPORTANCE In this study, a neglected but important role of apoE exchange in HCV LVP infectivity after virus assembly and release was identified. The data indicated that apoE expression level in uninfected cells is important for high permissiveness to HCV infection. Secreted apoE-associated lipoprotein specifically enhances infection of HCV LVPs. apoE exchange between HCV LVP and lipoproteins is important to maintain an adequate apoE level on LVPs for their efficient attachment to cell surface. These data defined for the first time an extracellular role of exchangeable apoE in HCV infection and suggested that exchangeable apolipoproteins reach a natural equilibrium between HCV LVPs and lipoprotein particles, which provides a new perspective to the understanding of the heterogeneity of HCV LVPs in composition.
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20
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Walsh MT, Hussain MM. Targeting microsomal triglyceride transfer protein and lipoprotein assembly to treat homozygous familial hypercholesterolemia. Crit Rev Clin Lab Sci 2016; 54:26-48. [PMID: 27690713 DOI: 10.1080/10408363.2016.1221883] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Homozygous familial hypercholesterolemia (HoFH) is a polygenic disease arising from defects in the clearance of plasma low-density lipoprotein (LDL), which results in extremely elevated plasma LDL cholesterol (LDL-C) and increased risk of atherosclerosis, coronary heart disease, and premature death. Conventional lipid-lowering therapies, such as statins and ezetimibe, are ineffective at lowering plasma cholesterol to safe levels in these patients. Other therapeutic options, such as LDL apheresis and liver transplantation, are inconvenient, costly, and not readily available. Recently, lomitapide was approved by the Federal Drug Administration as an adjunct therapy for the treatment of HoFH. Lomitapide inhibits microsomal triglyceride transfer protein (MTP), reduces lipoprotein assembly and secretion, and lowers plasma cholesterol levels by over 50%. Here, we explain the steps involved in lipoprotein assembly, summarize the role of MTP in lipoprotein assembly, explore the clinical and molecular basis of HoFH, and review pre-clinical studies and clinical trials with lomitapide and other MTP inhibitors for the treatment of HoFH. In addition, ongoing research and new approaches underway for better treatment modalities are discussed.
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Affiliation(s)
- Meghan T Walsh
- a School of Graduate Studies, Molecular and Cell Biology Program, State University of New York Downstate Medical Center , Brooklyn , NY , USA.,b Department of Cell Biology , State University of New York Downstate Medical Center , Brooklyn , NY , USA
| | - M Mahmood Hussain
- b Department of Cell Biology , State University of New York Downstate Medical Center , Brooklyn , NY , USA.,c Department of Pediatrics , SUNY Downstate Medical Center , Brooklyn , NY , USA.,d VA New York Harbor Healthcare System , Brooklyn , NY , USA , and.,e Winthrop University Hospital , Mineola , NY , USA
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21
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Interplay between hepatic mitochondria-associated membranes, lipid metabolism and caveolin-1 in mice. Sci Rep 2016; 6:27351. [PMID: 27272971 PMCID: PMC4894368 DOI: 10.1038/srep27351] [Citation(s) in RCA: 131] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 05/13/2016] [Indexed: 02/07/2023] Open
Abstract
The mitochondria-associated membrane (MAM) is a specialized subdomain of the endoplasmic reticulum (ER) which acts as an intracellular signaling hub. MAM dysfunction has been related to liver disease. We report a high-throughput mass spectrometry-based proteomics characterization of MAMs from mouse liver, which portrays them as an extremely complex compartment involved in different metabolic processes, including steroid metabolism. Interestingly, we identified caveolin-1 (CAV1) as an integral component of hepatic MAMs, which determine the relative cholesterol content of these ER subdomains. Finally, a detailed comparative proteomics analysis between MAMs from wild type and CAV1-deficient mice suggests that functional CAV1 contributes to the recruitment and regulation of intracellular steroid and lipoprotein metabolism-related processes accrued at MAMs. The potential impact of these novel aspects of CAV1 biology on global cell homeostasis and disease is discussed.
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22
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Fukuhara T, Ono C, Puig-Basagoiti F, Matsuura Y. Roles of Lipoproteins and Apolipoproteins in Particle Formation of Hepatitis C Virus. Trends Microbiol 2016; 23:618-629. [PMID: 26433694 DOI: 10.1016/j.tim.2015.07.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 07/07/2015] [Accepted: 07/20/2015] [Indexed: 02/06/2023]
Abstract
More than 160 million people worldwide are infected with hepatitis C virus (HCV), and cirrhosis and hepatocellular carcinoma induced by HCV infection are life-threatening diseases. HCV takes advantage of many aspects of lipid metabolism for an efficient propagation in hepatocytes. Due to the morphological and physiological similarities of HCV particles to lipoproteins, lipid-associated HCV particles are named lipoviroparticles. Recent analyses have revealed that exchangeable apolipoproteins directly interact with the viral membrane to generate infectious HCV particles. In this review, we summarize the roles of lipid metabolism in the life cycle of HCV.
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Affiliation(s)
- Takasuke Fukuhara
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Chikako Ono
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Francesc Puig-Basagoiti
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Yoshiharu Matsuura
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.
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23
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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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24
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Calattini S, Fusil F, Mancip J, Dao Thi VL, Granier C, Gadot N, Scoazec JY, Zeisel MB, Baumert TF, Lavillette D, Dreux M, Cosset FL. Functional and Biochemical Characterization of Hepatitis C Virus (HCV) Particles Produced in a Humanized Liver Mouse Model. J Biol Chem 2015; 290. [PMID: 26224633 PMCID: PMC4645586 DOI: 10.1074/jbc.m115.662999] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Lipoprotein components are crucial factors for hepatitis C virus (HCV) assembly and entry. As hepatoma cells producing cell culture-derived HCV (HCVcc) particles are impaired in some aspects of lipoprotein metabolism, it is of upmost interest to biochemically and functionally characterize the in vivo produced viral particles, particularly regarding how lipoprotein components modulate HCV entry by lipid transfer receptors such as scavenger receptor BI (SR-BI). Sera from HCVcc-infected liver humanized FRG mice were separated by density gradients. Viral subpopulations, termed HCVfrg particles, were characterized for their physical properties, apolipoprotein association, and infectivity. We demonstrate that, in contrast to the widely spread distribution of apolipoproteins across the different HCVcc subpopulations, the most infectious HCVfrg particles are highly enriched in apoE, suggesting that such apolipoprotein enrichment plays a role for entry of in vivo derived infectious particles likely via usage of apolipoprotein receptors. Consistent with this salient feature, we further reveal previously undefined functionalities of SR-BI in promoting entry of in vivo produced HCV. First, unlike HCVcc, SR-BI is a particularly limiting factor for entry of HCVfrg subpopulations of very low density. Second, HCVfrg entry involves SR-BI lipid transfer activity but not its capacity to bind to the viral glycoprotein E2. In conclusion, we demonstrate that composition and biophysical properties of the different subpopulations of in vivo produced HCVfrg particles modulate their levels of infectivity and receptor usage, hereby featuring divergences with in vitro produced HCVcc particles and highlighting the powerfulness of this in vivo model for the functional study of the interplay between HCV and liver components.
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Affiliation(s)
| | | | | | | | | | - Nicolas Gadot
- Structure Fédérative de Recherche (SFR) Lyon-Est, ANIPATH-Centre d'Histopathologie du Petit Animal de laboratoire, CNRS UMS3453-INSERM US7, 69372 Lyon, France
| | - Jean-Yves Scoazec
- Structure Fédérative de Recherche (SFR) Lyon-Est, ANIPATH-Centre d'Histopathologie du Petit Animal de laboratoire, CNRS UMS3453-INSERM US7, 69372 Lyon, France
| | - Mirjam B Zeisel
- INSERM, U1110, Institut des Maladies Virales et Hépatiques, 67000 Strasbourg, France, University of Strasbourg, 67000 Strasbourg, France, and
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25
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Phillips MC. Apolipoprotein E isoforms and lipoprotein metabolism. IUBMB Life 2015; 66:616-23. [PMID: 25328986 DOI: 10.1002/iub.1314] [Citation(s) in RCA: 199] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 09/09/2014] [Indexed: 11/09/2022]
Abstract
Apolipoprotein (apo) E is a 299-residue protein which functions as a key regulator of plasma lipid levels. Human apoE exists as three common isoforms and the parent form, apoE3, operates optimally in promoting clearance of triglyceride (TG)-rich lipoproteins and is associated with normal plasma lipid levels. This result occurs because apoE3 possesses both the requisite lipid-binding ability and affinity for the low density lipoprotein receptor (LDLR) to mediate appropriate lipolytic processing and endocytosis of TG-rich lipoprotein remnant particles. ApoE2 which differs from apoE3 by the single amino acid substitution Arg158Cys located near the LDLR recognition site exhibits impaired binding to the receptor and an inability to promote clearance of TG-rich lipoprotein remnant particles; this isoform is associated with Type-III hyperlipoproteinemia. ApoE4 which differs from apoE3 by the single amino acid substitution Cys112Arg is also associated with dyslipidemia although binding of this isoform to the LDLR is unaffected. The amino acid substitution affects the organization and stability of both the N-terminal helix bundle domain and separately folded C-terminal domain so that apoE4 has enhanced lipid binding ability. As a consequence, apoE4 binds better than apoE3 to the surface of very low density lipoprotein (VLDL) particles and impairs their lipolytic processing in the circulation so that apoE4 is associated with a more pro-atherogenic lipoprotein-cholesterol distribution (higher VLDL-cholesterol/high density lipoprotein-cholesterol ratio). This review summarizes current understanding of the structural differences between apoE2, apoE3, and apoE4, and the molecular mechanisms responsible for the alterations in lipoprotein metabolism resulting from this polymorphism of apoE. Detailed knowledge of how expression of structurally distinct apoE variants modifies lipoprotein metabolism provides a basis for developing ways to manipulate the functionality of apoE in vivo.
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Affiliation(s)
- Michael C Phillips
- Division of Translational Medicine and Human Genetics, Perelman School of Medicine at the University of Pennsylvania, 11-130 Translational Research Center, Philadelphia, PA, USA
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26
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Khetarpal SA, Rader DJ. Triglyceride-Rich Lipoproteins and Coronary Artery Disease Risk. Arterioscler Thromb Vasc Biol 2015; 35:e3-9. [DOI: 10.1161/atvbaha.114.305172] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Sumeet A. Khetarpal
- From the Departments of Genetics and Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Daniel J. Rader
- From the Departments of Genetics and Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia
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Yao Z, Zhang L, Ji G. Efficacy of polyphenolic ingredients of Chinese herbs in treating dyslipidemia of metabolic syndromes. JOURNAL OF INTEGRATIVE MEDICINE-JIM 2014; 12:135-46. [PMID: 24861834 DOI: 10.1016/s2095-4964(14)60023-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
There is an increasing interest and popularity of Chinese herbal medicine worldwide, which is accompanied by increasing concerns about its effectiveness and potential toxicity. Several ingredients, such as polyphenolic compounds berberine, flavonoids, and curcumin, have been studied extensively by using various animal models. Effectiveness of treatment and amelioration of metabolic syndromes, including insulin resistance and dyslipidemia, has been demonstrated. This review summarizes the major checkpoints and contributing factors in regulation of exogenous and endogenous lipid metabolism, with particular emphasis centered on triglyceride-rich and cholesterol-rich lipoproteins. Available experimental evidence demonstrating the lipid-lowering effect of berberine, flavonoids and curcumin in cell culture and animal models is compiled, and the strengths and shortcomings of experimental designs in these studies are discussed.
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Affiliation(s)
- Zemin Yao
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of System Biology, University of Ottawa, Ottawa K1H 8M5, Canada; E-mail:
| | - Li Zhang
- Institute of Digestive Diseases, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
| | - Guang Ji
- Institute of Digestive Diseases, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
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Apolipoprotein E likely contributes to a maturation step of infectious hepatitis C virus particles and interacts with viral envelope glycoproteins. J Virol 2014; 88:12422-37. [PMID: 25122793 DOI: 10.1128/jvi.01660-14] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED The assembly of infectious hepatitis C virus (HCV) particles is tightly linked to components of the very-low-density lipoprotein (VLDL) pathway. We and others have shown that apolipoprotein E (ApoE) plays a major role in production of infectious HCV particles. However, the mechanism by which ApoE contributes to virion assembly/release and how it gets associated with the HCV particle is poorly understood. We found that knockdown of ApoE reduces titers of infectious intra- and extracellular HCV but not of the related dengue virus. ApoE depletion also reduced amounts of extracellular HCV core protein without affecting intracellular core amounts. Moreover, we found that ApoE depletion affected neither formation of nucleocapsids nor their envelopment, suggesting that ApoE acts at a late step of assembly, such as particle maturation and infectivity. Importantly, we demonstrate that ApoE interacts with the HCV envelope glycoproteins, most notably E2. This interaction did not require any other viral proteins and depended on the transmembrane domain of E2 that also was required for recruitment of HCV envelope glycoproteins to detergent-resistant membrane fractions. These results suggest that ApoE plays an important role in HCV particle maturation, presumably by direct interaction with viral envelope glycoproteins. IMPORTANCE The HCV replication cycle is tightly linked to host cell lipid pathways and components. This is best illustrated by the dependency of HCV assembly on lipid droplets and the VLDL component ApoE. Although the role of ApoE for production of infectious HCV particles is well established, it is still poorly understood how ApoE contributes to virion formation and how it gets associated with HCV particles. Here, we provide experimental evidence that ApoE likely is required for an intracellular maturation step of HCV particles. Moreover, we demonstrate that ApoE associates with the viral envelope glycoproteins. This interaction appears to be dispensable for envelopment of virus particles but likely contributes to the quality control of secreted infectious virions. These results shed new light on the exploitation of host cell lipid pathways by HCV and the link of viral particle assembly to the VLDL component ApoE.
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Padden J, Megger DA, Bracht T, Reis H, Ahrens M, Kohl M, Eisenacher M, Schlaak JF, Canbay AE, Weber F, Hoffmann AC, Kuhlmann K, Meyer HE, Baba HA, Sitek B. Identification of novel biomarker candidates for the immunohistochemical diagnosis of cholangiocellular carcinoma. Mol Cell Proteomics 2014; 13:2661-72. [PMID: 25034945 PMCID: PMC4188994 DOI: 10.1074/mcp.m113.034942] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The aim of this study was the identification of novel biomarker candidates for the diagnosis of cholangiocellular carcinoma (CCC) and its immunohistochemical differentiation from benign liver and bile duct cells. CCC is a primary cancer that arises from the epithelial cells of bile ducts and is characterized by high mortality rates due to its late clinical presentation and limited treatment options. Tumorous tissue and adjacent non-tumorous liver tissue from eight CCC patients were analyzed by means of two-dimensional differential in-gel electrophoresis and mass-spectrometry-based label-free proteomics. After data analysis and statistical evaluation of the proteins found to be differentially regulated between the two experimental groups (fold change ≥ 1.5; p value ≤ 0.05), 14 candidate proteins were chosen for determination of the cell-type-specific expression profile via immunohistochemistry in a cohort of 14 patients. This confirmed the significant up-regulation of serpin H1, 14-3-3 protein sigma, and stress-induced phosphoprotein 1 in tumorous cholangiocytes relative to normal hepatocytes and non-tumorous cholangiocytes, whereas some proteins were detectable specifically in hepatocytes. Because stress-induced phosphoprotein 1 exhibited both sensitivity and specificity of 100%, an immunohistochemical verification examining tissue sections of 60 CCC patients was performed. This resulted in a specificity of 98% and a sensitivity of 64%. We therefore conclude that this protein should be considered as a potential diagnostic biomarker for CCC in an immunohistochemical application, possibly in combination with other candidates from this study in the form of a biomarker panel. This could improve the differential diagnosis of CCC and benign bile duct diseases, as well as metastatic malignancies in the liver.
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Affiliation(s)
- Juliet Padden
- From the ‡Medizinisches Proteom-Center, Ruhr-Universität Bochum, 44801 Bochum, Germany;
| | - Dominik A Megger
- From the ‡Medizinisches Proteom-Center, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Thilo Bracht
- From the ‡Medizinisches Proteom-Center, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Henning Reis
- ¶Institut für Pathologie, Universitätsklinikum Essen, Universität Duisburg-Essen, 45141 Essen, Germany
| | - Maike Ahrens
- From the ‡Medizinisches Proteom-Center, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Michael Kohl
- From the ‡Medizinisches Proteom-Center, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Martin Eisenacher
- From the ‡Medizinisches Proteom-Center, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Jörg F Schlaak
- ‖Klinik für Gastroenterologie und Hepatologie, Universitätsklinikum Essen, 45141 Essen, Universität Duisburg-Essen, 45141 Essen, Germany
| | - Ali E Canbay
- ‖Klinik für Gastroenterologie und Hepatologie, Universitätsklinikum Essen, 45141 Essen, Universität Duisburg-Essen, 45141 Essen, Germany
| | - Frank Weber
- **Klinik für Allgemeinchirurgie, Viszeral- und Transplantationschirurgie, Universitätsklinikum Essen, Universität Duisburg-Essen, 45141 Essen, Germany
| | - Andreas-Claudius Hoffmann
- ‡‡Innere Klinik (Tumorforschung), Westdeutsches Tumorzentrum, Universitätsklinikum Essen, Universität Duisburg-Essen, 45141 Essen, Germany
| | - Katja Kuhlmann
- From the ‡Medizinisches Proteom-Center, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Helmut E Meyer
- From the ‡Medizinisches Proteom-Center, Ruhr-Universität Bochum, 44801 Bochum, Germany; §§Leibniz Institute for Analytical Sciences - ISAS, 44139 Dortmund, Germany
| | - Hideo A Baba
- ¶Institut für Pathologie, Universitätsklinikum Essen, Universität Duisburg-Essen, 45141 Essen, Germany
| | - Barbara Sitek
- From the ‡Medizinisches Proteom-Center, Ruhr-Universität Bochum, 44801 Bochum, Germany;
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Tzeng TF, Lu HJ, Liou SS, Chang CJ, Liu IM. Lipid-lowering effects of zerumbone, a natural cyclic sesquiterpene of Zingiber zerumbet Smith, in high-fat diet-induced hyperlipidemic hamsters. Food Chem Toxicol 2014; 69:132-9. [PMID: 24709573 DOI: 10.1016/j.fct.2014.03.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 03/25/2014] [Accepted: 03/28/2014] [Indexed: 12/30/2022]
Abstract
We investigated the effects of zerumbone, a natural cyclic sesquiterpene of Zingiber zerumbet Smith, on high-fat diet (HFD)-induced hyperlipidemic hamsters. After being fed HFD for 2 weeks, Syrian golden hamsters were dosed orally with zerumbone (25, 50, and 100 mg/kg) once daily for 8 weeks. Decreased plasma levels of TC, TG and LDL-C, as well as the concentrations of hepatic lipids, with a simultaneous increase in fecal lipids were found. The ratios of LDL-C/HDL-C and TC/HDL-C were elevated by zerumbone. Zerumbone exhibited the ability to decreased hepatic mRNA levels of fatty acid synthase, malic enzyme, sterol-regulatory element binding protein and 3-hydroxy-3-methyl-glutaryl-CoA reductase reductase. The hepatic mRNA expression of peroxisome proliferator-activated receptor α, together with its target gene carnitine palmitoyl transferase and acyl-CoA oxidase were also upregulated by zerumbone. Zerumbone is effective to improve dyslipidemia by modulating the genes expression involving in the lipolytic and lipogenic pathways of lipids metabolism.
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Affiliation(s)
- Thing-Fong Tzeng
- Department of Internal Medicine, Pao Chien Hospital, Ping Tung City, Pingtung County, Taiwan, ROC
| | - Hung-Jen Lu
- Traditional Medicinal Center, Kaohsiung Veterans General Hospital, Kaohsiung City, Taiwan, ROC
| | - Shorong-Shii Liou
- Department of Pharmacy & Graduate Institute of Pharmaceutical Technology, Tajen University, Yanpu Shiang, Ping Tung Shien, Taiwan, ROC
| | - Chia Ju Chang
- Department of Pharmacy & Graduate Institute of Pharmaceutical Technology, Tajen University, Yanpu Shiang, Ping Tung Shien, Taiwan, ROC
| | - I-Min Liu
- Department of Pharmacy & Graduate Institute of Pharmaceutical Technology, Tajen University, Yanpu Shiang, Ping Tung Shien, Taiwan, ROC.
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Fisher E, Lake E, McLeod RS. Apolipoprotein B100 quality control and the regulation of hepatic very low density lipoprotein secretion. J Biomed Res 2014; 28:178-93. [PMID: 25013401 PMCID: PMC4085555 DOI: 10.7555/jbr.28.20140019] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 02/15/2014] [Indexed: 12/19/2022] Open
Abstract
Apolipoprotein B (apoB) is the main protein component of very low density lipoprotein (VLDL) and is necessary for the assembly and secretion of these triglyceride (TG)-rich particles. Following release from the liver, VLDL is converted to low density lipoprotein (LDL) in the plasma and increased production of VLDL can therefore play a detrimental role in cardiovascular disease. Increasing evidence has helped to establish VLDL assembly as a target for the treatment of dyslipidemias. Multiple factors are involved in the folding of the apoB protein and the formation of a secretion-competent VLDL particle. Failed VLDL assembly can initiate quality control mechanisms in the hepatocyte that target apoB for degradation. ApoB is a substrate for endoplasmic reticulum associated degradation (ERAD) by the ubiquitin proteasome system and for autophagy. Efficient targeting and disposal of apoB is a regulated process that modulates VLDL secretion and partitioning of TG. Emerging evidence suggests that significant overlap exists between these degradative pathways. For example, the insulin-mediated targeting of apoB to autophagy and postprandial activation of the unfolded protein response (UPR) may employ the same cellular machinery and regulatory cues. Changes in the quality control mechanisms for apoB impact hepatic physiology and pathology states, including insulin resistance and fatty liver. Insulin signaling, lipid metabolism and the hepatic UPR may impact VLDL production, particularly during the postprandial state. In this review we summarize our current understanding of VLDL assembly, apoB degradation, quality control mechanisms and the role of these processes in liver physiology and in pathologic states.
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Affiliation(s)
- Eric Fisher
- Biochemistry & Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Elizabeth Lake
- Biochemistry & Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Roger S McLeod
- Biochemistry & Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada
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GP73 is upregulated by hepatitis C virus (HCV) infection and enhances HCV secretion. PLoS One 2014; 9:e90553. [PMID: 24608522 PMCID: PMC3946557 DOI: 10.1371/journal.pone.0090553] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 01/31/2014] [Indexed: 12/17/2022] Open
Abstract
Hepatitis C virus (HCV) is a major cause of chronic liver disease. However, little is known about the details of its assembly and secretion. Golgi-related proteins have been recently proven to have a key function in HCV secretion. Golgi protein 73 (GP73), a resident Golgi membrane protein, is a potential serum biomarker for the diagnosis of liver diseases and hepatocellular carcinoma. Previous studies have demonstrated the upregulation of GP73 in the liver samples and sera of HCV-infected patients. However, the function and regulatory mechanism of GP73 in HCV infection at the cellular level remain unknown. In this study, we examined the expression level of GP73 in HCV infected cells and its effect on HCV life cycle in cell culture systems. Both the protein expression and mRNA levels of GP73 significantly increased in HCV subgenomic replicon-harboring cells and HCV-infected cells, which imply that GP73 was upregulated by HCV infection. HCV production was significantly enhanced when GP73 was overexpressed, but dramatically inhibited when GP73 was silenced. However, the overexpression and knockdown of GP73 showed no evident effect on the entry, protein translation, RNA replication, and assembly of HCV, which indicates that GP73 enhanced the secretion process. Moreover, the coiled-coil domain of GP73 was required to increase HCV secretion. GP73 increased and interacted with apolipoprotein E, an identified host factor that assists in HCV secretion. These results demonstrate the critical function of GP73 in HCV secretion and provide new insights into the therapeutic design of antiviral strategies.
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Mani S, Cao W, Wu L, Wang R. Hydrogen sulfide and the liver. Nitric Oxide 2014; 41:62-71. [PMID: 24582857 DOI: 10.1016/j.niox.2014.02.006] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 02/11/2014] [Accepted: 02/17/2014] [Indexed: 12/16/2022]
Abstract
Hydrogen sulfide (H2S) is a gasotransmitter that regulates numerous physiological and pathophysiological processes in our body. Enzymatic production of H2S is catalyzed by cystathionine γ-lyase (CSE), cystathionine β-synthase (CBS), and 3-mercaptopyruvate sulfurtransferase (MST). All these three enzymes present in the liver and via H2S production regulate liver functions. The liver is the hub for metabolism of glucose and lipids, and maintains the level of circulatory lipids through lipoprotein metabolism. Hepatic H2S metabolism affects glucose metabolism, insulin sensitivity, lipoprotein synthesis, mitochondrial biogenetics and biogenesis. Malfunction of hepatic H2S metabolism may be involved in many liver diseases, such as hepatic fibrosis and hepatic cirrhosis.
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Affiliation(s)
- Sarathi Mani
- Department of Biology, Lakehead University, Thunder Bay, Canada; Cardiovascular and Metabolic Research Unit, Lakehead University, Thunder Bay, Canada
| | - Wei Cao
- Cardiovascular and Metabolic Research Unit, Lakehead University, Thunder Bay, Canada; Thunder Bay Regional Research Institute, Thunder Bay, Canada; Department of Natural Medicine & Institute of Materia Medica, Fourth Military Medical University, Xi'an, China
| | - Lingyun Wu
- Cardiovascular and Metabolic Research Unit, Lakehead University, Thunder Bay, Canada; Thunder Bay Regional Research Institute, Thunder Bay, Canada; Department of Health Sciences, Lakehead University, Thunder Bay, Canada
| | - Rui Wang
- Department of Biology, Lakehead University, Thunder Bay, Canada; Cardiovascular and Metabolic Research Unit, Lakehead University, Thunder Bay, Canada.
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VerHague MA, Cheng D, Weinberg RB, Shelness GS. Apolipoprotein A-IV Expression in Mouse Liver Enhances Triglyceride Secretion and Reduces Hepatic Lipid Content by Promoting Very Low Density Lipoprotein Particle Expansion. Arterioscler Thromb Vasc Biol 2013; 33:2501-8. [DOI: 10.1161/atvbaha.113.301948] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Melissa A. VerHague
- From the Department of Pathology (M.A.V., D.C., G.S.S.), Department of Internal Medicine (R.B.W.), and Department of Physiology & Pharmacology (R.B.W.), Wake Forest School of Medicine, Winston-Salem, NC
| | - Dongmei Cheng
- From the Department of Pathology (M.A.V., D.C., G.S.S.), Department of Internal Medicine (R.B.W.), and Department of Physiology & Pharmacology (R.B.W.), Wake Forest School of Medicine, Winston-Salem, NC
| | - Richard B. Weinberg
- From the Department of Pathology (M.A.V., D.C., G.S.S.), Department of Internal Medicine (R.B.W.), and Department of Physiology & Pharmacology (R.B.W.), Wake Forest School of Medicine, Winston-Salem, NC
| | - Gregory S. Shelness
- From the Department of Pathology (M.A.V., D.C., G.S.S.), Department of Internal Medicine (R.B.W.), and Department of Physiology & Pharmacology (R.B.W.), Wake Forest School of Medicine, Winston-Salem, NC
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Demignot S, Beilstein F, Morel E. Triglyceride-rich lipoproteins and cytosolic lipid droplets in enterocytes: key players in intestinal physiology and metabolic disorders. Biochimie 2013; 96:48-55. [PMID: 23871915 DOI: 10.1016/j.biochi.2013.07.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 07/08/2013] [Indexed: 02/07/2023]
Abstract
During the post-prandial phase, intestinal triglyceride-rich lipoproteins (TRL) i.e. chylomicrons are the main contributors to the serum lipid level, which is linked to coronary artery diseases. Hypertriglyceridemia can originate from decreased clearance or increased production of TRL. During lipid absorption, enterocytes produce and secrete chylomicrons and transiently store lipid droplets (LDs) in the cytosol. The dynamic fluctuation of triglycerides in cytosolic LDs suggests that they contribute to TRL production and may thus control the length and amplitude of the post-prandial hypertriglyceridemia. In this review, we will describe the recent advances in the characterization of enterocytic LDs. The role of LDs in chylomicron production and secretion as well as potential previously unsuspected functions in the metabolism of vitamins, steroids and prostaglandins and in viral infection will also be discussed.
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Affiliation(s)
- Sylvie Demignot
- Université Pierre et Marie Curie, UMR S 872, Centre de Recherche des Cordeliers, Paris, France; Inserm, U 872, Paris, France; Ecole Pratique des Hautes Etudes, Laboratoire de Pharmacologie Cellulaire et Moléculaire, Paris, France; Université Paris Descartes, UMR S 872, Paris, France; Institut de Cardiométabolisme et Nutrition (ICAN), Paris, France.
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Podzielinski I, Saunders BA, Kimbler KD, Branscum AJ, Fung ET, DePriest PD, van Nagell JR, Ueland FR, Baron AT. Apolipoprotein concentrations are elevated in malignant ovarian cyst fluids suggesting that lipoprotein metabolism is dysregulated in epithelial ovarian cancer. Cancer Invest 2013; 31:258-72. [PMID: 23627408 DOI: 10.3109/07357907.2013.789896] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
SELDI-TOF MS analysis of ovarian cyst fluids revealed that peaks m/z 8696 and 8825 discriminate malignant, borderline, and benign tumors. These peaks correspond to isoforms of apoA2. ELISA demonstrates that apoA1, A2, B, C2, C3, and E cyst fluid concentrations are uncorrelated and higher in malignant ovarian tumors, but only apoA2, apoE, and age are independent classifiers of malignant ovarian tumors, yielding 55.1% sensitivity, 95% specificity, and 88.1% accuracy to discern malignant from benign and borderline tumors. These data suggest that lipoprotein metabolism is dysregulated in ovarian cancer and that apoA2 and apoE warrant further investigation as ovarian tumor biomarkers.
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Yao Z, Zhou H, Figeys D, Wang Y, Sundaram M. Microsome-associated lumenal lipid droplets in the regulation of lipoprotein secretion. Curr Opin Lipidol 2013; 24:160-70. [PMID: 23123764 DOI: 10.1097/mol.0b013e32835aebe7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE OF REVIEW Liver is the major organ in mammals that possesses the capacity to release triglyceride within VLDL. VLDL assembly requires apolipoprotein (apo) B-100 with the assistance of microsomal triglyceride transfer protein (MTP), which facilitates the mobilization of triglyceride into the microsomal lumen. Recent experimental evidence has suggested that the lumenal triglyceride associated with endoplasmic reticulum (ER)/Golgi may represent an entity serving as precursors for large VLDL1. RECENT FINDINGS Under lipid-rich conditions, discrete triglyceride-rich lipidic bodies, termed lumenal lipid droplets, are accumulated in association with ER/Golgi microsomes. Formation of the microsome-associated lumenal lipid droplets (MALD) is dependent on the activity of MTP, and the resulting apoB-free lipidic body is associated with a variety of proteins including apolipoproteins that are components of VLDL. Formation and utilization of MALD during the assembly and secretion of VLDL1 have a profound influence on hepatic cell physiology, such as ER stress responses. SUMMARY This review summarizes current understanding of hepatic triglyceride homeostasis in general, and highlights the functional significance of triglyceride compartmentalization between cytosol and microsomes in particular. Understanding of MALD metabolism may shed new light on the prevention and treatment of liver diseases associated with abnormally elevated intracellular triglycerides.
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Affiliation(s)
- Zemin Yao
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario, Canada.
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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: 57] [Impact Index Per Article: 4.8] [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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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: 15] [Impact Index Per Article: 1.3] [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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40
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Yao Z. New Developments in Hepatic Lipoprotein Production and Clinical Relevance. Arterioscler Thromb Vasc Biol 2012; 32:1072. [DOI: 10.1161/atvbaha.112.249995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Zemin Yao
- From the Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada
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