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Thomas SR, Zhang Y, Rye KA. The pleiotropic effects of high-density lipoproteins and apolipoprotein A-I. Best Pract Res Clin Endocrinol Metab 2022; 37:101689. [PMID: 36008277 DOI: 10.1016/j.beem.2022.101689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The high density lipoprotein (HDL) fraction of human plasma consists of multiple subpopulations of spherical particles that are structurally uniform, but heterogeneous in terms of size, composition and function. Numerous epidemiological studies have established that an elevated high density lipoprotein cholesterol (HDL-C) level is associated with decreased cardiovascular risk. However, with several recent randomised clinical trials of HDL-C raising agents failing to reduce cardiovascular events, contemporary research is transitioning towards clinical development of the cardioprotective functions of HDLs and the identification of functions that can be exploited for treatment of other diseases. This review describes the origins of HDLs and the causes of their compositional and functional heterogeneity. It then summarises current knowledge of how cardioprotective and other functions of HDLs are regulated. The final section of the review summarises recent advances in the clinical development of HDL-targeted therapies.
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Affiliation(s)
- Shane R Thomas
- Cardiometabolic Disease Research Group, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
| | - Yunjia Zhang
- Cardiometabolic Disease Research Group, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
| | - Kerry-Anne Rye
- Cardiometabolic Disease Research Group, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
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Illiano P, Brambilla R, Parolini C. The mutual interplay of gut microbiota, diet and human disease. FEBS J 2020; 287:833-855. [DOI: 10.1111/febs.15217] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 12/21/2019] [Accepted: 01/16/2020] [Indexed: 12/16/2022]
Affiliation(s)
- Placido Illiano
- The Miami Project to Cure Paralysis Department of Neurological Surgery University of Miami Miller School of Medicine FL USA
| | - Roberta Brambilla
- The Miami Project to Cure Paralysis Department of Neurological Surgery University of Miami Miller School of Medicine FL USA
- Department of Neurobiology Research Institute of Molecular Medicine University of Southern Denmark Odense Denmark
- Department of Clinical Research BRIDGE‐Brain Research‐Inter‐Disciplinary Guided Excellence University of Southern Denmark Odense C Denmark
| | - Cinzia Parolini
- Department of Pharmacological and Biomolecular Sciences Università degli Studi di Milano Italy
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Parolini C. A Compendium of the Biological Effects of Apolipoprotein A-IMilano. J Pharmacol Exp Ther 2019; 372:54-62. [DOI: 10.1124/jpet.119.261719] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/22/2019] [Indexed: 12/17/2022] Open
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Parolini C. Effects of Fish n-3 PUFAs on Intestinal Microbiota and Immune System. Mar Drugs 2019; 17:E374. [PMID: 31234533 PMCID: PMC6627897 DOI: 10.3390/md17060374] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/13/2019] [Accepted: 06/20/2019] [Indexed: 02/06/2023] Open
Abstract
Studies over several decades have documented the beneficial actions of n-3 polyunsaturated fatty acids (PUFAs), which are plentiful in fish oil, in different disease states. Mechanisms responsible for the efficacy of n-3 PUFAs include: (1) Reduction of triglyceride levels; (2) anti-arrhythmic and antithrombotic effects, and (3) resolution of inflammatory processes. The human microbiota project and subsequent studies using next-generation sequencing technology have highlighted that thousands of different microbial species are present in the human gut, and that there has been a significant variability of taxa in the microbiota composition among people. Several factors (gestational age, mode of delivery, diet, sanitation and antibiotic treatment) influence the bacterial community in the human gastrointestinal tract, and among these diet habits play a crucial role. The disturbances in the gut microbiota composition, i.e., gut dysbiosis, have been associated with diseases ranging from localized gastrointestinal disorders to neurologic, respiratory, metabolic, ocular, and cardiovascular illnesses. Many studies have been published about the effects of probiotics and prebiotics on the gut microbiota/microbioma. On the contrary, PUFAs in the gut microbiota have been less well defined. However, experimental studies suggested that gut microbiota, n-3 PUFAs, and host immune cells work together to ensure the intestinal wall integrity. This review discussed current evidence concerning the links among gut microbiota, n-3 PUFAs intake, and human inflammatory disease.
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Affiliation(s)
- Cinzia Parolini
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20122 Milano, Italy.
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Function of different proportions of apolipoprotein A-I cysteine mutants and apolipoprotein A-V on recombinant high-density lipoproteins in vitro. Biosci Rep 2019; 39:BSR20190547. [PMID: 31023964 PMCID: PMC6522722 DOI: 10.1042/bsr20190547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/10/2019] [Accepted: 04/23/2019] [Indexed: 11/17/2022] Open
Abstract
To explore the anti-atherosclerotic effects of recombinant high-density lipoproteins (rHDL) of apolipoprotein AI wild-type (apoA-Iwt), apolipoprotein AI Milano (apoA-IM), apolipoprotein AI (N74C) (apoA-I (N74C) )and apolipoprotein AV (apoA-V). We constructed rHDL liposomes (rHDLs), which included apoA-Iwt, apoA-IM, and apoA-I (N74C), followed by the synthesis of rHDLs, with the indicated ratios of apoA-Iwt, apoA-IM, apoA-I (N74C) and apoA-V. We investigated the anti-atherosclerotic effects by experiments including the DMPC clearance assay and experiments that assessed the in vitro antioxidation against low-density lipoprotein, the cellular uptake of oxidized low-density lipoprotein (oxLDL) and the in vitro intracellular lipid accumulation. Electron microscopy results revealed that as more apoA-V was present in rHDLs, the particle size of rHDLs was larger. The DMPC clearance assay subsequently showed that rHDL protein mixtures could promote DMPC turbidity clearance when more apoA-V was included in the reaction mixtures, with apoAV-rHDL showing the strongest turbidity clearance ability (P<0.05 vs AI-rHDL). In vitro antioxidation against low-density lipoprotein assays indicated that rHDLs containing apoA-V had increasing oxidation resistance against low-density lipoprotein (LDL) with higher apoA-V contents. Finally, cellular uptake of oxLDL and intracellular lipids suggested an apparent oxidation resistance to LDL oxidation in vitro and a reduced intracellular lipid accumulation in THP-1-derived macrophages, with AIM-rHDL demonstrating the greatest ability to decrease intracellular lipid accumulation. Different proportions of apolipoprotein A-I cysteine mutants and apolipoprotein A-V of rHDL changed the lipid binding capacity, particle size, and antioxidant capacity. These changes may show a beneficial effect of rHDL on atherosclerosis.
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Chroni A, Kardassis D. HDL Dysfunction Caused by Mutations in apoA-I and Other Genes that are Critical for HDL Biogenesis and Remodeling. Curr Med Chem 2019. [DOI: 10.2174/0929867325666180313114950] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The “HDL hypothesis” which suggested that an elevation in HDL cholesterol
(HDL-C) levels by drugs or by life style changes should be paralleled by a decrease in the
risk for Cardiovascular Disease (CVD) has been challenged by recent epidemiological and
clinical studies using HDL-raising drugs. HDL components such as proteins, lipids or small
RNA molecules, but not cholesterol itself, possess various atheroprotective functions in different
cell types and accumulating evidence supports the new hypothesis that HDL functionality
is more important than HDL-C levels for CVD risk prediction. Thus, the detailed characterization
of changes in HDL composition and functions in various pathogenic conditions
is critically important in order to identify new biomarkers for diagnosis, prognosis and therapy
monitoring of CVD. Here we provide an overview of how HDL composition, size and
functionality are affected in patients with monogenic disorders of HDL metabolism due to
mutations in genes that participate in the biogenesis and the remodeling of HDL. We also review
the findings from various mouse models with genetic disturbances in the HDL biogenesis
pathway that have been generated for the validation of the data obtained in human patients
and how these models could be utilized for the evaluation of novel therapeutic strategies such
as the use of adenovirus-mediated gene transfer technology that aim to correct HDL abnormalities.
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Affiliation(s)
- Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research , Greece
| | - Dimitris Kardassis
- Department of Basic Medical Sciences, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology of Hellas, Heraklion 71003, Greece
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Busnelli M, Manzini S, Sirtori CR, Chiesa G, Parolini C. Effects of Vegetable Proteins on Hypercholesterolemia and Gut Microbiota Modulation. Nutrients 2018; 10:E1249. [PMID: 30200592 PMCID: PMC6164761 DOI: 10.3390/nu10091249] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 08/30/2018] [Accepted: 09/03/2018] [Indexed: 12/19/2022] Open
Abstract
Risk assessment tools, i.e., validated risk prediction algorithms, to estimate the patient's 10-year risk of developing cardiovascular disease (CVD) should be used to identify high-risk people for primary prevention. Current evidence confirms that appropriate monitoring and control of risk factors either reduces the likelihood of CVD or slows down its progression. It is thus crucial that all health professionals make appropriate use of all the available intervention strategies to control risk factors: from dietary improvement and adequate physical activity to the use of functional foods, food supplements, and drugs. The gut microbiota, which encompasses 1 × 1014 resident microorganisms, has been recently recognized as a contributing factor in the development of human disease. This review examines the effect of both some vegetable food components belong to the "protein food group" and the underexploited protein-rich hempseed on cholesterolemia and gut microbiota composition.
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Affiliation(s)
- Marco Busnelli
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milano, Italy.
| | - Stefano Manzini
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milano, Italy.
| | - Cesare R Sirtori
- Centro Dislipidemie, A.S.S.T. Grande Ospedale Metropolitano Niguarda, 220162 Milano, Italy.
| | - Giulia Chiesa
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milano, Italy.
| | - Cinzia Parolini
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milano, Italy.
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Bisgaier CL, Ackermann R, Rea T, Rodrigueza WV, Hartman D. ApoA-IMilano phospholipid complex (ETC-216) infusion in human volunteers. Insights into the phenotypic characteristics of ApoA-IMilano carriers. Pharmacol Res 2016; 111:86-99. [DOI: 10.1016/j.phrs.2016.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 05/02/2016] [Accepted: 05/02/2016] [Indexed: 12/15/2022]
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Arnaboldi F, Busnelli M, Cornaghi L, Manzini S, Parolini C, Dellera F, Ganzetti GS, Sirtori CR, Donetti E, Chiesa G. High-density lipoprotein deficiency in genetically modified mice deeply affects skin morphology: A structural and ultrastructural study. Exp Cell Res 2015; 338:105-12. [PMID: 26241937 DOI: 10.1016/j.yexcr.2015.07.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/29/2015] [Accepted: 07/30/2015] [Indexed: 01/20/2023]
Abstract
Cutaneous lipids, endogenously synthetized and transported by lipoproteins, play a pivotal role in maintaining skin barrier. An impairment of extracutaneous lipid trafficking leads to the development of xanthomas, mostly arising in hyperlipidemic patients, but also in subjects with high-density lipoprotein (HDL) deficiency. The aim of this work was to evaluate, in a genetically modified mouse model, lacking two protein components of HDL particles, apolipoprotein(apo)E and apoA-I, the effect of HDL deficiency on skin morphology. Control mice (C57BL/6), apoE deficient mice (EKO), apoA-I deficient mice (A-IKO) and apoA-I/apoE double knockout mice (A-IKO/EKO) were maintained on a low-fat/low-cholesterol diet up to 30 weeks of age. At sacrifice, skin biopsies were processed for light (LM) and transmission electron microscopy (TEM). Whereas the skin of EKO, A-IKO, and C57BL/6 mice was comparable, LM analysis in A-IKO/EKO mice showed an increase in dermal thickness and the presence of foam cells and T lymphocytes in reticular dermis. TEM analysis revealed the accumulation of cholesterol clefts in the papillary dermis and of cholesterol crystals within foam cells. In conclusion, A-IKO/EKO mice represent an experimental model for investigating the cutaneous phenotype of human HDL deficiency, thus mimicking a condition in which human xanthomatous lesions can develop.
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Affiliation(s)
- Francesca Arnaboldi
- Department of Biomedical Sciences for Health, Laboratory of Structural and Ultrastructural Morphology, Italy.
| | - Marco Busnelli
- Department of Pharmacological and Biomolecular Sciences, Laboratory of Pharmacology of Dyslipidemias and Atherosclerosis, Università degli Studi di Milano, Milan, Italy
| | - Laura Cornaghi
- Department of Biomedical Sciences for Health, Laboratory of Structural and Ultrastructural Morphology, Italy
| | - Stefano Manzini
- Department of Pharmacological and Biomolecular Sciences, Laboratory of Pharmacology of Dyslipidemias and Atherosclerosis, Università degli Studi di Milano, Milan, Italy
| | - Cinzia Parolini
- Department of Pharmacological and Biomolecular Sciences, Laboratory of Pharmacology of Dyslipidemias and Atherosclerosis, Università degli Studi di Milano, Milan, Italy
| | - Federica Dellera
- Department of Pharmacological and Biomolecular Sciences, Laboratory of Pharmacology of Dyslipidemias and Atherosclerosis, Università degli Studi di Milano, Milan, Italy
| | - Giulia Sara Ganzetti
- Department of Pharmacological and Biomolecular Sciences, Laboratory of Pharmacology of Dyslipidemias and Atherosclerosis, Università degli Studi di Milano, Milan, Italy
| | - Cesare Riccardo Sirtori
- Department of Pharmacological and Biomolecular Sciences, Laboratory of Pharmacology of Dyslipidemias and Atherosclerosis, Università degli Studi di Milano, Milan, Italy
| | - Elena Donetti
- Department of Biomedical Sciences for Health, Laboratory of Structural and Ultrastructural Morphology, Italy
| | - Giulia Chiesa
- Department of Pharmacological and Biomolecular Sciences, Laboratory of Pharmacology of Dyslipidemias and Atherosclerosis, Università degli Studi di Milano, Milan, Italy
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11
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Parolini C, Manzini S, Busnelli M, Rigamonti E, Marchesi M, Diani E, Sirtori CR, Chiesa G. Effect of the combinations between pea proteins and soluble fibres on cholesterolaemia and cholesterol metabolism in rats. Br J Nutr 2013; 110:1394-401. [PMID: 23458494 DOI: 10.1017/s0007114513000639] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Many functional foods and dietary supplements have been reported to be beneficial for the management of dyslipidaemia, one of the major risk factors for CVD. Soluble fibres and legume proteins are known to be a safe and practical approach for cholesterol reduction. The present study aimed at investigating the hypocholesterolaemic effect of the combinations of these bioactive vegetable ingredients and their possible effects on the expression of genes regulating cholesterol homeostasis. A total of six groups of twelve rats each were fed, for 28 d, Nath's hypercholesterolaemic diets, differing in protein and fibre sources, being, respectively, casein and cellulose (control), pea proteins and cellulose (pea), casein and oat fibres (oat), casein and apple pectin (pectin), pea proteins and oat fibres (pea+oat) and pea proteins and apple pectin (pea+pectin). Administration of each vegetable-containing diet was associated with lower total cholesterol concentrations compared with the control. The combinations (pea+oat and pea+pectin) were more efficacious than fibres alone in modulating cholesterolaemia ( - 53 and - 54%, respectively, at 28 d; P< 0·005). In rats fed the diets containing oat fibres or apple pectin, alone or in combination with pea proteins, a lower hepatic cholesterol content (P< 0·005) and higher hepatic mRNA concentrations of CYP7A1 and NTCP were found when compared with the control rats (P< 0·05). In summary, the dietary combinations of pea proteins and oat fibres or apple pectin are extremely effective in lowering plasma cholesterol concentrations in rats and affect cellular cholesterol homeostasis by up-regulating genes involved in hepatic cholesterol turnover.
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Affiliation(s)
- Cinzia Parolini
- Department of Pharmacological Sciences, Università degli Studi di Milano, via Balzaretti 9, 20133 Milan, Italy
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12
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Moradi H, Said HM, Vaziri ND. Post-transcriptional nature of uremia-induced downregulation of hepatic apolipoprotein A-I production. Transl Res 2013; 161:477-85. [PMID: 23219399 PMCID: PMC3609941 DOI: 10.1016/j.trsl.2012.11.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 11/06/2012] [Accepted: 11/08/2012] [Indexed: 01/17/2023]
Abstract
Chronic kidney disease is associated with premature death from cardiovascular disease, which is, in part, driven by high density lipoprotein deficiency and dysfunction. One of the main causes of high density lipoprotein deficiency in chronic kidney disease is diminished plasma apolipoprotein (Apo)A-I level. Plasma ApoA-I is reduced in dialysis patients and hepatic ApoA-I messenger RNA (mRNA) is decreased in the uremic rats. This study explored the mechanism of uremia-induced downregulation of ApoA-I. Human hepatoma derived cells were incubated in media containing whole plasma or plasma subfractionation from normal subjects and patients with end stage renal disease pre- and posthemodialysis. Cells and culture media were isolated to measure ApoA-I protein and mRNA. ApoA-I promoter activity was measured using transfection with a luciferase promoter construct containing the -2096 to +293 segment of ApoA-I gene. Finally, effect of uremic and control plasma was assessed on ApoA-I RNA stability. Exposure to uremic plasma significantly reduced ApoA-I mRNA expression and ApoA-I protein production. These effects were reversed by replacing uremic plasma with normal plasma. Although no difference in ApoA-I promoter activity was found between cells exposed to uremic and normal plasma, uremic plasma significantly reduced ApoA-I RNA stability. Experiments using plasma subfractions revealed that the inhibitory effect of uremic plasma on ApoA-I mRNA expression resides in fractions containing molecules larger but not smaller than 30 kd. The pre- and postdialysis plasma exerted an equally potent inhibitory effect on ApoA-I mRNA abundance. Uremia lowers ApoA-I production by reducing its RNA stability. The inhibitory effect of uremic milieu on ApoA-I mRNA expression is mediated by non-dialyzable molecule(s) larger than 30 kd.
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Affiliation(s)
- Hamid Moradi
- Division of Nephrology and Hypertension, University of California, Irvine, Irvine, CA 92697, USA
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Chehade JM, Alcalde R, Naem E, Mooradian AD, Wong NCW, Haas MJ. Induction of apolipoprotein A-I gene expression by glucagon-like peptide-1 and exendin-4 in hepatocytes but not intestinal cells. Metabolism 2013; 62:265-74. [PMID: 22901716 DOI: 10.1016/j.metabol.2012.07.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Revised: 07/11/2012] [Accepted: 07/11/2012] [Indexed: 10/28/2022]
Abstract
OBJECTIVE Diabetic dyslipidemia is an important risk factor for the development of macrovascular complications. Recent clinical trials suggest that diabetics treated with glucagon-like peptide-1 (GLP-1) have normalized lipid levels, including an increase in plasma high-density lipoprotein cholesterol (HDLc) levels. METHODS To determine if GLP-1 (7-36 amide) and the GLP-1-like insulinotropic peptide exendin-4 regulate expression of apolipoprotein A-I (apo A-I), the primary anti-atherogenic component of high-density lipoprotein (HDL), HepG2 hepatocytes and Caco-2 intestinal cells, representative of tissues that express the majority of apo A-I, were treated with increasing amounts of each peptide and apo A-I gene expression was measured in the conditioned medium. RESULTS Apo A-I secretion increased in both GLP-1 and exendin-4-treated HepG2, but not Caco-2 cells, and this was accompanied by similar changes in apo A-I mRNA levels and apo A-I promoter activity. Induction of apo A-I promoter activity by GLP-1 and exendin-4 required an SP1-responsive element. Hepatic ATP binding cassette protein A1 (ABCA1) expression, but not scavenger receptor class B type1 receptor expression was also induced by GLP-1 and exendin-4. CONCLUSIONS These results suggest that GLP-1- and exendin-4-mediated changes in HDLc are likely due to changes in hepatic expression of apo A-I and ABCA1.
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Affiliation(s)
- Joe M Chehade
- Division of Endocrinology, Department of Medicine, University of Florida-Jacksonville College of Medicine, Jacksonville, FL 32209, USA
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Naem E, Haas MJ, Wong NCW, Mooradian AD. Endoplasmic reticulum stress in HepG2 cells inhibits apolipoprotein A-I secretion. Life Sci 2012; 92:72-80. [PMID: 23154241 DOI: 10.1016/j.lfs.2012.11.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 10/03/2012] [Accepted: 10/30/2012] [Indexed: 10/27/2022]
Abstract
AIMS Endoplasmic reticulum (ER) stress modulates gene expression and has been implicated in causing dyslipidemias. To determine if ER stress may contribute to hypoalphalipoproteinemia through suppression of apo A-I gene expression, human hepatoma cell line Hep G2 was treated with ER stress inducers and the changes in apo A-I gene expression were compared to albumin gene expression. MAIN METHODS HepG2 cells were treated with tunicamycin (TM) and thapsigargin (TG), two potent inducers of ER stress, and apo A-I and albumin protein levels, mRNA levels, and promoter activity were measured. ER stress was measured using the ER stress-responsive alkaline phosphatase assay and by Western blot quantitation of ER stress markers such as glucose-regulated protein-78 (GRP-78), phosphorylated Jun N-terminal kinase (phospho-JNK), total JNK, phosphorylated eukaryotic initiation factor 2 alpha (phospho eIF2α), and total eIF2α. KEY FINDINGS TM and TG induced ER stress in HepG2 cells and reduced apo A-I and albumin secretion in a dose-dependent manner. Intracellular albumin levels increased in cells treated with TM and TG while intracellular apo A-I levels decreased. Albumin mRNA and albumin gene promoter activity were reduced in proportion to the decrease in albumin secreted while changes in the apo A-I mRNA levels and promoter activity were modest and did not account for the reduction in apo A-I secretion. SIGNIFICANCE These results indicate that apo A-I secretion is inhibited by ER stress possibly by affecting cellular degradation pathways. However, ER stress does not affect apo A-I secretion by regulating gene expression.
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Affiliation(s)
- Emad Naem
- The Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Florida, Jacksonville College of Medicine, Jacksonville, FL 32209, USA
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Parolini C, Caligari S, Gilio D, Manzini S, Busnelli M, Montagnani M, Locatelli M, Diani E, Giavarini F, Caruso D, Roda E, Roda A, Sirtori CR, Chiesa G. Reduced biliary sterol output with no change in total faecal excretion in mice expressing a human apolipoprotein A-I variant. Liver Int 2012; 32:1363-71. [PMID: 22845860 DOI: 10.1111/j.1478-3231.2012.02855.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 06/07/2012] [Accepted: 06/28/2012] [Indexed: 12/12/2022]
Abstract
BACKGROUND/AIMS Apolipoprotein (apo)A-I(M) (ilano), is a molecular variant of apoA-I(wild-type), associated with dramatically low HDL-cholesterol levels, but no increased risk for cardiovascular disease. In view of the present uncertainties on the role of apoA-I in liver cholesterol removal by way of bile acids and neutral sterols, and of the greater capacity of apoA-I(M) (ilano) to remove arterial cholesterol, biliary sterol metabolism was evaluated in transgenic mice expressing apoA-I(M) (ilano). METHODS ApoA-I(M) (ilano) mice were fed a high-cholesterol/high-fat diet, and compared with human apoA-I(wild-type) mice. Plasma lipid levels, hepatic bile flow and composition, hepatic and intestinal cholesterol and bile acid content, and faecal sterol content were measured. Moreover, the expression of hepatic ABCA1, SR-B1 and that of hepatic and intestinal genes involved in bile acid metabolism were evaluated. RESULTS The dietary treatment led to a strong elevation in HDL-cholesterol levels in A-I(M) (ilano) mice, associated with an increased expression of hepatic ABCA1. ApoA-I(M) (ilano) mice showed lower cholesterol output from the liver compared with apoA-I(wild-type) mice, in the absence of liver sterol accumulation. Faecal excretion of neutral sterols and bile acids was similar in the two mouse lines. CONCLUSIONS In spite of a different response to the dietary challenge, with an increased ABCA1 expression and a lower hepatic cholesterol output in apoA-I(M) (ilano) mice, the net sterol excretion is comparable in the two transgenic lines.
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Affiliation(s)
- Cinzia Parolini
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
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Naem E, Alcalde R, Gladysz M, Mesliniene S, Jaimungal S, Sheikh-Ali M, Haas MJ, Wong NCW, Mooradian AD. Inhibition of apolipoprotein A-I gene by the aryl hydrocarbon receptor: a potential mechanism for smoking-associated hypoalphalipoproteinemia. Life Sci 2012; 91:64-9. [PMID: 22727790 DOI: 10.1016/j.lfs.2012.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 05/29/2012] [Accepted: 06/07/2012] [Indexed: 10/28/2022]
Abstract
AIMS Smokers have lower plasma concentrations of high-density lipoprotein (HDL) cholesterol and apolipoprotein A-I (apo A-I) compared with nonsmokers. To determine the molecular basis of this observation, the effect of activation of the aryl hydrocarbon receptor (AhR) on apo A-I gene expression was examined. MAIN METHODS HepG2 cells were treated with AhR receptor agonists benzo(a)pyrene (BaP) and CAY10465, and AhR receptor antagonist CAY10464 and apo A-I protein, mRNA levels and promoter activity were measured. The effect of nicotine on apo A-I protein secretion was also tested. Using a series or apo A-I gene promoter deletion constructs, a xenobiotic response element (XRE) was identified. KEY FINDINGS Treatment of HepG2 cells with the AhR receptor agonists BaP and CAY10465, inhibited apo A-I protein synthesis while nicotine, which does not bind AhR had no effect. Benzo(a)pyrene treatment also suppressed apo A-I mRNA and gene promoter activity. Treatment of HepG2 cells with the AhR receptor antagonist CAY10464 reversed the suppressive effect of BaP on apo A-I gene expression. A putative xenobiotic response element (XRE) was identified between nucleotides -325 and -186 (relative to the transcriptional start site, +1). SIGNIFICANCE These results suggest that the cigarette smoking related environmental contaminant BaP promotes hypoalphalipoproteinemia in part through activation of the hepatic AhR.
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Affiliation(s)
- Emad Naem
- Department of Medicine, University of Florida, Jacksonville College of Medicine, Jacksonville, FL, USA
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Sorci-Thomas MG, Zabalawi M, Bharadwaj MS, Wilhelm AJ, Owen JS, Asztalos BF, Bhat S, Thomas MJ. Dysfunctional HDL containing L159R ApoA-I leads to exacerbation of atherosclerosis in hyperlipidemic mice. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:502-12. [PMID: 21944998 DOI: 10.1016/j.bbalip.2011.08.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 08/20/2011] [Accepted: 08/31/2011] [Indexed: 11/16/2022]
Abstract
The mutation L159R apoA-I or apoA-I(L159R) (FIN) is a single amino acid substitution within the sixth helical repeat of apoA-I. It is associated with a dominant negative phenotype, displaying hypoalphaproteinemia and an increased risk for atherosclerosis in humans. Mice lacking both mouse apoA-I and LDL receptor (LDL(-/-), apoA-I(-/-)) (double knockout or DKO) were crossed>9 generations with mice transgenic for human FIN to obtain L159R apoA-I, LDLr(-/-), ApoA-I(-/-) (FIN-DKO) mice. A similar cross was also performed with human wild-type (WT) apoA-I (WT-DKO). In addition, FIN-DKO and WT-DKO were crossed to obtain WT/FIN-DKO mice. To determine the effects of the apoA-I mutations on atherosclerosis, groups of each genotype were fed either chow or an atherogenic diet for 12weeks. Interestingly, the production of dysfunctional HDL-like particles occurred in DKO and FIN-DKO mice. These particles were distinct with respect to size, and their enrichment in apoE and cholesterol esters. Two-dimensional gel electrophoresis indicated that particles found in the plasma of FIN-DKO mice migrated as large α(3)-HDL. Atherosclerosis analysis showed that FIN-DKO mice developed the greatest extent of aortic cholesterol accumulation compared to all other genotypes, including DKO mice which lack any apoA-I. Taken together these data suggest that the presence of large apoE enriched HDL particles containing apoA-I L159R lack the normal cholesterol efflux promoting properties of HDL, rendering them dysfunctional and pro-atherogenic. In conclusion, large HDL-like particles containing apoE and apoA-I(L159R) contribute rather than protect against atherosclerosis, possibly through defective efflux properties and their potential for aggregation at their site of interaction in the aorta. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).
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Affiliation(s)
- Mary G Sorci-Thomas
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
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Bhat S, Sorci-Thomas MG, Calabresi L, Samuel MP, Thomas MJ. Conformation of dimeric apolipoprotein A-I milano on recombinant lipoprotein particles. Biochemistry 2010; 49:5213-24. [PMID: 20524691 DOI: 10.1021/bi1003734] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Apolipoprotein A-I Milano (apoA-I(Milano)) is a naturally occurring human mutation of wild-type apolipoprotein A-I (apoA-I(WT)) having cystine substituted for arginine(173). Two molecules of apo-I(WT) form disks with phospholipid having a defined relationship between the apoA-I(WT) molecules. ApoA-I(Milano) forms cystine homodimers that would not allow the protein to adopt the conformation reported for apoA-I(WT). The conformational constraints for dimeric apoA-I(Milano) recombinant high-density lipoprotein (rHDL) disks made with phospholipid were deduced from a combination of chemical cross-linking and mass spectrometry. Lysine-selective homobifunctional cross-linkers were reacted with homogeneous rHDL having diameters of 78 and 125 A. After reduction, cross-linked apoA-I(Milano) was separated from monomeric apoprotein by gel electrophoresis and then subjected to in-gel trypsin digest. Cross-linked peptides were confirmed by MS/MS sequencing. The cross-links provided distance constraints that were used to refine models of lipid-bound dimeric apoA-I(Milano). These studies suggest that a single dimeric apoA-I(Milano) on 78 A diameter rHDL girdles the edge of a phospholipid disk assuming a "belt" conformation similar to the "belt" region of apoA-I(WT) on rHDL. However, the C-terminal end of dimeric apoA-I(Milano) wraps around the periphery of the particle to shield the fatty acid chains from water rather than folding back onto the "belt" as does apoA-I(WT). The two apoA-I(Milano) dimers on a 125 A diameter rHDL do not encircle the periphery of a phospholipid disk but appear to reside on the surface of a laminar micelle.
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Affiliation(s)
- Shaila Bhat
- Department of Pathology, Center for Lipid Science, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, North Carolina 27157, USA
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The intracellular quality control system down-regulates the secretion of amyloidogenic apolipoprotein A-I variants: a possible impact on the natural history of the disease. Biochim Biophys Acta Mol Basis Dis 2010; 1812:87-93. [PMID: 20637862 DOI: 10.1016/j.bbadis.2010.07.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Accepted: 07/02/2010] [Indexed: 11/20/2022]
Abstract
Hereditary systemic amyloidosis caused by apolipoprotein A-I variants is a dominantly inherited disease characterised by fibrillar deposits mainly localized in the kidneys, liver, testis and heart. We have previously shown that the apolipoprotein A-I variant circulates in plasma at lower levels than the wild-type form (Mangione et al., 2001; Obici et al., 2004) thus raising the possibility that the amyloid deposits could sequester the circulating amyloidogenic chain or that the intracellular quality control can catch and capture the misfolded amyloidogenic chain before the secretion. In this study we have measured plasma levels of the wild-type and the variant Leu75Pro apolipoprotein A-I in two young heterozygous carriers in which tissue amyloid deposition was still absent. In both cases, the mutant was present at significantly lower levels than the wild-type form, thus indicating that the low plasma concentration of the apolipoprotein A-I variant is not a consequence of the protein entrapment in the amyloid deposits. In order to explore the cell secretion of amyloidogenic apolipoprotein A-I variants, we have studied COS-7 cells expressing either wild-type apolipoprotein A-I or two amyloidogenic mutants: Leu75Pro and Leu174Ser. Quantification of intracellular and extracellular apolipoprotein A-I alongside the intra-cytoplasmatic localization indicates that, unlike the wild-type protein, both variants are retained within the cells and mainly accumulate in the endoplasmic reticulum. The low plasma concentration of amyloidogenic apolipoprotein A-I may therefore be ascribed to the activity of the intracellular quality control that represents a first line of defence against the secretion of pathogenic variants.
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Rigamonti E, Parolini C, Marchesi M, Diani E, Brambilla S, Sirtori CR, Chiesa G. Hypolipidemic effect of dietary pea proteins: Impact on genes regulating hepatic lipid metabolism. Mol Nutr Food Res 2010; 54 Suppl 1:S24-30. [PMID: 20077421 DOI: 10.1002/mnfr.200900251] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Controversial data on the lipid-lowering effect of dietary pea proteins have been provided and the mechanisms behind this effect are not completely understood. The aim of the study was to evaluate a possible hypolipidemic activity of a pea protein isolate and to determine whether pea proteins could affect the hepatic lipid metabolism through regulation of genes involved in cholesterol and fatty acid homeostasis. Rats were fed Nath's hypercholesterolemic diets for 28 days, the protein sources being casein or a pea protein isolate from Pisum sativum. After 14 and 28 days of dietary treatment, rats fed pea proteins had markedly lower plasma cholesterol and triglyceride levels than rats fed casein (p<0.05). Pea protein-fed rats displayed higher hepatic mRNA levels of LDL receptor versus those fed casein (p<0.05). Hepatic mRNA concentration of genes involved in fatty acids synthesis, such as fatty acid synthase and stearoyl-CoA desaturase, was lower in pea protein-fed rats than in rats fed casein (p<0.05). In conclusion, the present study demonstrates a marked cholesterol and triglyceride-lowering activity of pea proteins in rats. Moreover, pea proteins appear to affect cellular lipid homeostasis by upregulating genes involved in hepatic cholesterol uptake and by downregulating fatty acid synthesis genes.
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Affiliation(s)
- Elena Rigamonti
- Department of Pharmacological Sciences, Università degli Studi di Milano, Milan, Italy
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Mallikarjuna K, Sundaram CS, Sharma Y, Deepa PR, Khetan V, Gopal L, Biswas J, Sharma T, Krishnakumar S. Comparative proteomic analysis of differentially expressed proteins in primary retinoblastoma tumors. Proteomics Clin Appl 2010; 4:449-63. [DOI: 10.1002/prca.200900069] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 10/12/2009] [Accepted: 11/08/2009] [Indexed: 12/17/2022]
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Feng Y, Van Craeyveld E, Jacobs F, Lievens J, Snoeys J, De Geest B. Wild-type apo A-I and apo A-I(Milano) gene transfer reduce native and transplant arteriosclerosis to a similar extent. J Mol Med (Berl) 2008; 87:287-97. [PMID: 19066833 DOI: 10.1007/s00109-008-0427-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 10/29/2008] [Accepted: 11/27/2008] [Indexed: 10/21/2022]
Abstract
Apolipoprotein (apo) A-I(Milano) is an apo A-I mutant characterized by a cysteine for arginine substitution at position 173. Apo A-I(Milano) carriers have much less atherosclerosis than expected from their low plasma high-density lipoprotein cholesterol levels, suggesting that this mutant may have superior atheroprotective properties. Here, we compare the effect of hepatocyte-directed gene transfer of wild-type human apo A-I and human apo A-I(Milano) on endothelial progenitor cell (EPC) biology and on the progression of native atherosclerosis and allograft vasculopathy in C57BL/6 apo E(-/-) mice. Human apo A-I and apo A-I(Milano) transfer resulted in an equivalent increase of EPC number and function as well as EPC incorporation and endothelial regeneration in allografts and inhibited the progression of native atherosclerosis and allograft vasculopathy to a similar extent. In conclusion, the current head-to-head comparison indicates that human apo A-I(Milano) transfer is not superior compared to wild-type human apo A-I transfer.
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Affiliation(s)
- Yingmei Feng
- Center for Molecular and Vascular Biology, Campus Gasthuisberg, University of Leuven, Herestraat, Belgium
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Coimbra S, Santos-Silva A, Rocha-Pereira P, Rocha S, Castro E. Green tea consumption improves plasma lipid profiles in adults. Nutr Res 2006. [DOI: 10.1016/j.nutres.2006.09.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Wait R, Chiesa G, Parolini C, Miller I, Begum S, Brambilla D, Galluccio L, Ballerio R, Eberini I, Gianazza E. Reference maps of mouse serum acute-phase proteins: Changes with LPS-induced inflammation and apolipoprotein A-I and A-II transgenes. Proteomics 2005; 5:4245-53. [PMID: 16196095 DOI: 10.1002/pmic.200401292] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We present reference maps of the mouse serum proteome (run under reducing and non-reducing conditions), from control animals, from mice injected with lipopolysaccharide (LPS) to induce systemic inflammation, and from mice transgenic for human apolipoproteins A-I and A-II. Seventy-seven spots/spot chains from the reducing gels were identified by HPLC MS/MS, representing 28 distinct proteins, including a species-specific protease inhibitor, contrapsin, and high levels of carboxylesterase. The concentrations of acute-phase reactants were monitored for 96 h after LPS challenge. The greatest changes (four-fold 48 h after LPS administration) were observed for haptoglobin and hemopexin. Orosomucoid/alpha(1)-acid glycoprotein and apolipoprotein A-I increased steadily, to 50-60% above baseline at 96 h from stimulation. In mice transgenic for human apolipoprotein A-I the levels of expression of orosomucoid/alpha(1)-acid glycoprotein, alpha(1)-macroglobulin, esterase, kininogen and contrapsin were altered compared to knockout mice lacking apolipoprotein A-I. In contrast, except for the presence of apolipoprotein A-II, no statistically significant difference was observed in mice transgenic for human apolipoprotein A-II.
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Affiliation(s)
- Robin Wait
- Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College London, UK
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Bhat S, Zabalawi M, Willingham MC, Shelness GS, Thomas MJ, Sorci-Thomas MG. Quality control in the apoA-I secretory pathway. J Lipid Res 2004; 45:1207-20. [PMID: 15060083 DOI: 10.1194/jlr.m300498-jlr200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
From a total of 47 known apolipoprotein A-I (apoA-I) mutations, only 18 are linked to low plasma HDL apoA-I concentrations, and 78% of these map to apoA-I helices 6 and 7 (residues 143-186). Gene transfer and transgenic mouse studies have shown that several helix 6 apoA-I mutations have reduced hepatic HDL production. Our objective was to examine the impact of helix 6 modifications on intracellular biosynthetic processing and secretion of apoA-I. Cells were transfected with wild-type or mutant apoA-I, radiolabeled with [(35)S]Met/Cys, and then placed in unlabeled medium for up to 4 h. Results show that >90% of newly synthesized wild-type apoA-I was secreted by 60 min. Over the same length of time, only 20% of helix 6 deletion mutant (Delta 6 apoA-I) was secreted, whereas 80% remained cell associated. Microscopic and biochemical studies revealed that cell-associated Delta 6 apoA-I was located predominantly within the cytoplasm as lipid-protein inclusions, whereas wild-type apoA-I was localized in the endoplasmic reticulum/Golgi. Results using other helix deletions or helix 6 substitution mutations indicated that only complete removal of helix 6 resulted in massive cytoplasmic accumulation. These data suggest that alterations in native apoA-I conformation can lead to aberrant trafficking and accumulation of apolipoprotein-phospholipid structures. Thus, conformation-dependent alterations in intracellular trafficking and turnover may underlie the reduced plasma HDL concentrations observed in individuals harboring deletion mutations within helix 6.
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Affiliation(s)
- Shaila Bhat
- Department of Pathology, Wake Forest University Health Sciences, Winston-Salem, NC, USA
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