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Jennelle LT, Magoro T, Angelucci AR, Dandekar A, Hahn YS. Hepatitis C Virus Alters Macrophage Cholesterol Metabolism Through Interaction with Scavenger Receptors. Viral Immunol 2022; 35:223-235. [PMID: 35467430 PMCID: PMC9063163 DOI: 10.1089/vim.2021.0101] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Lipid accumulation and inflammation act together to induce, sustain, and further development of chronic liver disease. Hepatitis C virus (HCV) infection induces metabolic and immune changes in liver macrophages, promoting lipid accumulation and inflammation that synergize and culminate in the development of steatohepatitis and fibrogenesis. Chronic HCV patients have increased liver macrophages with disruptions in cholesterol metabolism and alterations in inflammatory mediators. While HCV-induced changes in inflammatory mediators are well documented, how HCV triggers metabolic change in macrophages is unknown. In this report, we examined the mechanism of macrophage sensing of HCV to cause metabolic impairment and subsequent immune dysfunction. We demonstrate that HCV protein and RNA kinetics in macrophages are distinct from hepatocytes. In macrophages, HCV RNAs and protein accumulate rapidly after exposure but internalized RNAs quickly decline to a low-level set point. Notably, exposure of macrophages to HCV resulted in increased lipids and cholesterol and activation of cholesterol-sensing, immunomodulatory liver X receptors (LXRs). Furthermore, we provide evidence that HCV RNA accumulation in macrophages occurs through scavenging receptors. These results suggest that HCV released from infected hepatocytes stimulates accumulation of lipids and activation of LXR in macrophages contributing to metabolic changes involved in HCV-induced chronic liver disease. Our results provide novel insight into mechanisms through which impaired lipid metabolism in macrophages associated with HCV infection promotes development of liver steatohepatitis and fibrosis.
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Affiliation(s)
- Lucas T. Jennelle
- Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Tshifhiwa Magoro
- Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Angelina R. Angelucci
- Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Aditya Dandekar
- Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Young S. Hahn
- Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
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Larrazabal C, Silva LMR, Pervizaj-Oruqaj L, Herold S, Hermosilla C, Taubert A. P-Glycoprotein Inhibitors Differently Affect Toxoplasma gondii, Neospora caninum and Besnoitia besnoiti Proliferation in Bovine Primary Endothelial Cells. Pathogens 2021; 10:pathogens10040395. [PMID: 33806177 PMCID: PMC8065907 DOI: 10.3390/pathogens10040395] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 12/12/2022] Open
Abstract
Apicomplexan parasites are obligatory intracellular protozoa. In the case of Toxoplasma gondii, Neospora caninum or Besnoitia besnoiti, to ensure proper tachyzoite production, they need nutrients and cell building blocks. However, apicomplexans are auxotrophic for cholesterol, which is required for membrane biosynthesis. P-glycoprotein (P-gp) is a transmembrane transporter involved in xenobiotic efflux. However, the physiological role of P-gp in cholesterol metabolism is unclear. Here, we analyzed its impact on parasite proliferation in T. gondii-, N. caninum- and B. besnoiti-infected primary endothelial cells by applying different generations of P-gp inhibitors. Host cell treatment with verapamil and valspodar significantly diminished tachyzoite production in all three parasite species, whereas tariquidar treatment affected proliferation only in B. besnoiti. 3D-holotomographic analyses illustrated impaired meront development driven by valspodar treatment being accompanied by swollen parasitophorous vacuoles in the case of T. gondii. Tachyzoite and host cell pre-treatment with valspodar affected infection rates in all parasites. Flow cytometric analyses revealed verapamil treatment to induce neutral lipid accumulation. The absence of a pronounced anti-parasitic impact of tariquidar, which represents here the most selective P-gp inhibitor, suggests that the observed effects of verapamil and valspodar are associated with mechanisms independent of P-gp. Out of the three species tested here, this compound affected only B. besnoiti proliferation and its effect was much milder as compared to verapamil and valspodar.
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Affiliation(s)
- Camilo Larrazabal
- Biomedical Research Center Seltersberg, Institute of Parasitology, Justus Liebig University Giessen, 35392 Giessen, Germany; (L.M.R.S.); (C.H.); (A.T.)
- Correspondence:
| | - Liliana M. R. Silva
- Biomedical Research Center Seltersberg, Institute of Parasitology, Justus Liebig University Giessen, 35392 Giessen, Germany; (L.M.R.S.); (C.H.); (A.T.)
| | - Learta Pervizaj-Oruqaj
- The Cardio-Pulmonary Institute (CPI), 35392 Giessen, Germany; (L.P.-O.); (S.H.)
- Member of the German Center for Lung Research (DZL), Department of Pulmonary and Critical Care Medicine and Infectious Diseases, Universities of Giessen and Marburg Lung Center (UGMLC), Justus-Liebig University Giessen, 35392 Giessen, Germany
| | - Susanne Herold
- The Cardio-Pulmonary Institute (CPI), 35392 Giessen, Germany; (L.P.-O.); (S.H.)
- Member of the German Center for Lung Research (DZL), Department of Pulmonary and Critical Care Medicine and Infectious Diseases, Universities of Giessen and Marburg Lung Center (UGMLC), Justus-Liebig University Giessen, 35392 Giessen, Germany
| | - Carlos Hermosilla
- Biomedical Research Center Seltersberg, Institute of Parasitology, Justus Liebig University Giessen, 35392 Giessen, Germany; (L.M.R.S.); (C.H.); (A.T.)
| | - Anja Taubert
- Biomedical Research Center Seltersberg, Institute of Parasitology, Justus Liebig University Giessen, 35392 Giessen, Germany; (L.M.R.S.); (C.H.); (A.T.)
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Chouhan S, Singh S, Athavale D, Ramteke P, Vanuopadath M, Nair BG, Nair SS, Bhat MK. Sensitization of hepatocellular carcinoma cells towards doxorubicin and sorafenib is facilitated by glucose-dependent alterations in reactive oxygen species, P-glycoprotein and DKK4. J Biosci 2020. [DOI: 10.1007/s12038-020-00065-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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4
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Burns VE, Kerppola TK. ATR-101 inhibits cholesterol efflux and cortisol secretion by ATP-binding cassette transporters, causing cytotoxic cholesterol accumulation in adrenocortical carcinoma cells. Br J Pharmacol 2017; 174:3315-3332. [PMID: 28710789 DOI: 10.1111/bph.13951] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 06/22/2017] [Accepted: 07/07/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE To further the development of new agents for the treatment of adrenocortical carcinoma (ACC), we characterized the molecular and cellular mechanisms of cytotoxicity by the adrenalytic compound ATR-101 (PD132301-02). EXPERIMENTAL APPROACH We compared the effects of ATR-101, PD129337, and ABC transporter inhibitors on cholesterol accumulation and efflux, on cortisol secretion, on ATP levels, and on caspase activation in ACC-derived cell lines. We examined the effects of these compounds in combination with methyl-β-cyclodextrin or exogenous cholesterol to determine the roles of altered cholesterol levels in the effects of these compounds. KEY RESULTS ATR-101 caused cholesterol accumulation, ATP depletion, and caspase activation within 30 minutes after addition to ACC-derived cells, whereas PD129337 did not. Suppression of cholesterol accumulation by methyl-β-cyclodextrin or exogenous cholesterol, prevented ATP depletion and caspase activation by ATR-101. ATR-101 blocked cholesterol efflux and cortisol secretion, suggesting that it inhibited ABCA1, ABCG1, and MDR1 transporters. Combinations of ABCA1, ABCG1, and MDR1 inhibitors were also cytotoxic. Combinations of ATR-101 with inhibitors of ABCG1, MDR1, or mitochondrial functions had increased cytotoxicity. Inhibitors of steroidogenesis reduced ATP depletion by ATR-101, whereas U18666A enhanced cholesterol accumulation and ATP depletion together with ATR-101. ATR-101 repressed ABCA1, ABCG1, and IDOL transcription by mechanisms that were distinct from the mechanisms that caused cholesterol accumulation. CONCLUSIONS AND IMPLICATIONS Inhibition of multiple ABC transporters and the consequent accumulation of cholesterol mediated the cytotoxicity of ATR-101. Compounds that replicate these effects in tumours are likely to be useful in the treatment of ACC.
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Affiliation(s)
| | - Tom Klaus Kerppola
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
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Generation of Cholinergic and Dopaminergic Interneurons from Human Pluripotent Stem Cells as a Relevant Tool for In Vitro Modeling of Neurological Disorders Pathology and Therapy. Stem Cells Int 2016; 2016:5838934. [PMID: 28105055 PMCID: PMC5220531 DOI: 10.1155/2016/5838934] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 11/03/2016] [Accepted: 11/09/2016] [Indexed: 01/24/2023] Open
Abstract
The cellular and molecular bases of neurological diseases have been studied for decades; however, the underlying mechanisms are not yet fully elucidated. Compared with other disorders, diseases of the nervous system have been very difficult to study mainly due to the inaccessibility of the human brain and live neurons in vivo or in vitro and difficulties in examination of human postmortem brain tissue. Despite the availability of various genetically engineered animal models, these systems are still not adequate enough due to species variation and differences in genetic background. Human induced pluripotent stem cells (hiPSCs) reprogrammed from patient somatic cells possess the potential to differentiate into any cell type, including neural progenitor cells and postmitotic neurons; thus, they open a new area to in vitro modeling of neurological diseases and their potential treatment. Currently, many protocols for generation of various neuronal subtypes are being developed; however, most of them still require further optimization. Here, we highlight accomplishments made in the generation of dopaminergic and cholinergic neurons, the two subtypes most affected in Alzheimer's and Parkinson's diseases and indirectly affected in Huntington's disease. Furthermore, we discuss the potential role of hiPSC-derived neurons in the modeling and treatment of neurological diseases related to dopaminergic and cholinergic system dysfunction.
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Bouchareychas L, Pirault J, Saint-Charles F, Deswaerte V, Le Roy T, Jessup W, Giral P, Le Goff W, Huby T, Gautier EL, Lesnik P. Promoting macrophage survival delays progression of pre-existing atherosclerotic lesions through macrophage-derived apoE. Cardiovasc Res 2015; 108:111-23. [PMID: 26092098 DOI: 10.1093/cvr/cvv177] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 06/11/2015] [Indexed: 12/14/2022] Open
Abstract
AIMS Macrophage apoptosis is a prominent feature of atherosclerosis, yet whether cell death-protected macrophages would favour the resolution of already established atherosclerotic lesions, and thus hold therapeutic potential, remains unknown. METHODS AND RESULTS We irradiated then transplanted into Apoe(-/-) or LDLr(-/-) recipient mice harbouring established atherosclerotic lesions, bone marrow cells from mice displaying enhanced macrophage survival through overexpression of the antiapoptotic gene hBcl-2 (Mø-hBcl2 Apoe(-/-) or Mø-hBcl2 Apoe(+/+) LDLr(-/-)). Both recipient mice exhibited decreased lesional apoptotic cell content and reduced necrotic areas when repopulated with Mø-hBcl2 mouse-derived bone marrow cells. In contrast, only LDLr(-/-) recipients showed a reduction in plasma cholesterol levels and in atherosclerotic lesions. The absence of significant reduction of plasma cholesterol levels in the context of apoE deficiency highlighted macrophage-derived apoE as key in both the regulation of plasma and tissue cholesterol levels and the progression of pre-existing lesion. Accordingly, hBcl2 expression in macrophages was associated with larger pools of Kupffer cells and Ly-6C(low) monocytes, both high producers of apoE. Additionally, increased Kupffer cells population was associated with improved clearance of apoptotic cells and modified lipoproteins. CONCLUSION Collectively, these data show that promoting macrophage survival provides a supplemental source of apoE, which hinders pre-existing plaque progression.
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Affiliation(s)
- Laura Bouchareychas
- INSERM, UMR_S U1166, Integrative Biology of Atherosclerosis Team, Hôpital de la Pitié, Pavillon Benjamin Delessert, 83 Boulevard de L'hôpital, Paris F-75013, France Sorbonne Universités, UPMC Université Paris 06, UMR_S 1166, ICAN, Integrative Biology of Atherosclerosis Team, Paris F-75005, France
| | - John Pirault
- INSERM, UMR_S U1166, Integrative Biology of Atherosclerosis Team, Hôpital de la Pitié, Pavillon Benjamin Delessert, 83 Boulevard de L'hôpital, Paris F-75013, France Sorbonne Universités, UPMC Université Paris 06, UMR_S 1166, ICAN, Integrative Biology of Atherosclerosis Team, Paris F-75005, France
| | - Flora Saint-Charles
- INSERM, UMR_S U1166, Integrative Biology of Atherosclerosis Team, Hôpital de la Pitié, Pavillon Benjamin Delessert, 83 Boulevard de L'hôpital, Paris F-75013, France Sorbonne Universités, UPMC Université Paris 06, UMR_S 1166, ICAN, Integrative Biology of Atherosclerosis Team, Paris F-75005, France
| | - Virginie Deswaerte
- INSERM, UMR_S U1166, Integrative Biology of Atherosclerosis Team, Hôpital de la Pitié, Pavillon Benjamin Delessert, 83 Boulevard de L'hôpital, Paris F-75013, France Sorbonne Universités, UPMC Université Paris 06, UMR_S 1166, ICAN, Integrative Biology of Atherosclerosis Team, Paris F-75005, France
| | - Tiphaine Le Roy
- INSERM, UMR_S U1166, Integrative Biology of Atherosclerosis Team, Hôpital de la Pitié, Pavillon Benjamin Delessert, 83 Boulevard de L'hôpital, Paris F-75013, France Institute of Cardiometabolism and Nutrition, ICAN, AP-HP, Pitié-Salpêtrière Hospital, Paris F-75013, France
| | - Wendy Jessup
- Atherosclerosis Group, ANZAC Research Institute, University of Sydney and Concord Hospital, Sydney, Australia
| | - Philippe Giral
- INSERM, UMR_S U1166, Integrative Biology of Atherosclerosis Team, Hôpital de la Pitié, Pavillon Benjamin Delessert, 83 Boulevard de L'hôpital, Paris F-75013, France Institute of Cardiometabolism and Nutrition, ICAN, AP-HP, Pitié-Salpêtrière Hospital, Paris F-75013, France
| | - Wilfried Le Goff
- INSERM, UMR_S U1166, Integrative Biology of Atherosclerosis Team, Hôpital de la Pitié, Pavillon Benjamin Delessert, 83 Boulevard de L'hôpital, Paris F-75013, France Sorbonne Universités, UPMC Université Paris 06, UMR_S 1166, ICAN, Integrative Biology of Atherosclerosis Team, Paris F-75005, France Institute of Cardiometabolism and Nutrition, ICAN, AP-HP, Pitié-Salpêtrière Hospital, Paris F-75013, France
| | - Thierry Huby
- INSERM, UMR_S U1166, Integrative Biology of Atherosclerosis Team, Hôpital de la Pitié, Pavillon Benjamin Delessert, 83 Boulevard de L'hôpital, Paris F-75013, France Sorbonne Universités, UPMC Université Paris 06, UMR_S 1166, ICAN, Integrative Biology of Atherosclerosis Team, Paris F-75005, France Institute of Cardiometabolism and Nutrition, ICAN, AP-HP, Pitié-Salpêtrière Hospital, Paris F-75013, France
| | - Emmanuel L Gautier
- INSERM, UMR_S U1166, Integrative Biology of Atherosclerosis Team, Hôpital de la Pitié, Pavillon Benjamin Delessert, 83 Boulevard de L'hôpital, Paris F-75013, France Sorbonne Universités, UPMC Université Paris 06, UMR_S 1166, ICAN, Integrative Biology of Atherosclerosis Team, Paris F-75005, France Institute of Cardiometabolism and Nutrition, ICAN, AP-HP, Pitié-Salpêtrière Hospital, Paris F-75013, France
| | - Philippe Lesnik
- INSERM, UMR_S U1166, Integrative Biology of Atherosclerosis Team, Hôpital de la Pitié, Pavillon Benjamin Delessert, 83 Boulevard de L'hôpital, Paris F-75013, France Sorbonne Universités, UPMC Université Paris 06, UMR_S 1166, ICAN, Integrative Biology of Atherosclerosis Team, Paris F-75005, France Institute of Cardiometabolism and Nutrition, ICAN, AP-HP, Pitié-Salpêtrière Hospital, Paris F-75013, France
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Celestino AT, Levy D, Maria Ruiz JL, Bydlowski SP. ABCB1, ABCC1, and LRP gene expressions are altered by LDL, HDL, and serum deprivation in a human doxorubicin-resistant uterine sarcoma cell line. Biochem Biophys Res Commun 2015; 457:664-8. [DOI: 10.1016/j.bbrc.2015.01.045] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 01/10/2015] [Indexed: 12/22/2022]
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Szalat R, Pirault J, Fermand JP, Carrié A, Saint-Charles F, Olivier M, Robillard P, Frisdal E, Villard EF, Cathébras P, Bruckert E, Chapman MJ, Giral P, Guerin M, Lesnik P, Le Goff W. Physiopathology of necrobiotic xanthogranuloma with monoclonal gammopathy. J Intern Med 2014; 276:269-84. [PMID: 24428816 PMCID: PMC4279948 DOI: 10.1111/joim.12195] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
RATIONALE Xanthomatosis associated with monoclonal gammopathy includes hyperlipidaemic xanthoma (HX), normolipidaemic xanthoma (NX) and necrobiotic xanthogranuloma (NXG). All three pathologies are characterized by skin or visceral lesions related to cholesterol accumulation, monoclonal immunoglobulin (MIg) and hypocomplementemia. The pathophysiology underlying NXG remains unknown although the involvement of MIg is suspected. OBJECTIVE To provide further insights into the pathophysiology of NXG, we evaluated the plasma lipid phenotype, mechanisms involved in cellular cholesterol accumulation and role of MIg in an analysis of blood and plasma markers of inflammation in 16 patients with xanthomatosis [NXG (n = 8) and NX (n = 8)] associated with monoclonal IgG relative to the relevant controls. RESULTS The lipid profile of patients with NXG was characterized by a low HDL-C phenotype and an abnormal distribution of HDL particles. Sera from patients with NXG induced cholesterol accumulation in human macrophages. This accumulation was due in part to a significant reduction in the HDL capacity to promote cholesterol efflux from macrophages, which was not found in the case of NX. The MIg of NXG and NX patients was tested positively by ELISA to recognize a large spectrum of lipoproteins. High plasma levels of pro-inflammatory cytokines (TNFα and IL-6), soluble cytokine receptors (sIL-6R, sTNFRI and sTNFRII), adhesion molecules (VCAM-1 and ICAM-1) and chemokines (MCP-1, IL-8 and MIP-1α) were observed in both patients with NXG and NX, revealing a specific xanthoma inflammatory signature which was inversely correlated with plasma levels of anti-inflammatory HDL. However, patients with NXG were distinguished by elevated levels of IL-15 and a marked increase in the rate of intermediate CD14++CD16+ monocytes. CONCLUSION This study revealed that NXG is characterized by impaired macrophage lipid homeostasis associated with a systemic inflammatory profile that may result from the interaction of MIg and lipoproteins.
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Affiliation(s)
- R Szalat
- Département d'immunologie Clinique, Hôpital Saint Louis, Paris, France; EA3963, Université Paris 7 Denis Diderot, INSERM, IFR105, Institut Universitaire d'Hématologie, Paris, France
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To KKW, Hu M, Tomlinson B. Expression and activity of ABCG2, but not ABCB1 or OATP1B1, are associated with cholesterol levels: evidence from in vitro and in vivo experiments. Pharmacogenomics 2014; 15:1091-104. [DOI: 10.2217/pgs.14.58] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Aim: This study investigated whether cholesterol levels influence the expression and function of drug transporters and whether statin treatments could alter this by reducing plasma low-density lipoprotein cholesterol levels. Patients & methods: The mRNA expression and function of OATP1B1, ABCB1 and ABCG2 were assessed in peripheral blood mononuclear cells (PBMCs) of healthy subjects and from patients with familial hypercholesterolemia (FH) before and after statin treatment by real-time PCR and flow cytometric assay, respectively. The effects of statin exposure and cholesterol depletion in PBMCs and in cell lines were assessed. Results: ABCG2 expression and activity in PBMCs in patients with FH were 2-fold and 26-fold higher, respectively, than those of the healthy subjects (p < 0.001 for both). Statin treatment decreased ABCG2 expression and function in patients with FH. Depletion of cholesterol ex vivo reduced ABCG2 expression in PBMCs and reduced ABCG2 activity in liver and colon cells. Conclusion: This study suggested that statins may downregulate ABCG2 expression and function through reducing low-density lipoprotein cholesterol levels. Original submitted 25 November 2013; Revision submitted 21 March 2014
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Affiliation(s)
- Kenneth KW To
- School of Pharmacy, The Chinese University of Hong Kong, Hong Kong SAR
| | - Miao Hu
- Department of Medicine & Therapeutics, The Chinese University of Hong Kong, Hong Kong SAR
| | - Brian Tomlinson
- Department of Medicine & Therapeutics, The Chinese University of Hong Kong, Hong Kong SAR
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El Khoury P, Plengpanich W, Frisdal E, Le Goff W, Khovidhunkit W, Guerin M. Improved plasma cholesterol efflux capacity from human macrophages in patients with hyperalphalipoproteinemia. Atherosclerosis 2014; 234:193-9. [PMID: 24674903 DOI: 10.1016/j.atherosclerosis.2014.02.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 02/20/2014] [Accepted: 02/27/2014] [Indexed: 11/25/2022]
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Bocchetta S, Maillard P, Yamamoto M, Gondeau C, Douam F, Lebreton S, Lagaye S, Pol S, Helle F, Plengpanich W, Guérin M, Bourgine M, Michel ML, Lavillette D, Roingeard P, le Goff W, Budkowska A. Up-regulation of the ATP-binding cassette transporter A1 inhibits hepatitis C virus infection. PLoS One 2014; 9:e92140. [PMID: 24646941 PMCID: PMC3960176 DOI: 10.1371/journal.pone.0092140] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 02/18/2014] [Indexed: 12/12/2022] Open
Abstract
Hepatitis C virus (HCV) establishes infection using host lipid metabolism pathways that are thus considered potential targets for indirect anti-HCV strategies. HCV enters the cell via clathrin-dependent endocytosis, interacting with several receptors, and virus-cell fusion, which depends on acidic pH and the integrity of cholesterol-rich domains of the hepatocyte membrane. The ATP-binding Cassette Transporter A1 (ABCA1) mediates cholesterol efflux from hepatocytes to extracellular Apolipoprotein A1 and moves cholesterol within cell membranes. Furthermore, it generates high-density lipoprotein (HDL) particles. HDL protects against arteriosclerosis and cardiovascular disease. We show that the up-regulation of ABCA1 gene expression and its cholesterol efflux function in Huh7.5 hepatoma cells, using the liver X receptor (LXR) agonist GW3965, impairs HCV infection and decreases levels of virus produced. ABCA1-stimulation inhibited HCV cell entry, acting on virus-host cell fusion, but had no impact on virus attachment, replication, or assembly/secretion. It did not affect infectivity or properties of virus particles produced. Silencing of the ABCA1 gene and reduction of the specific cholesterol efflux function counteracted the inhibitory effect of the GW3965 on HCV infection, providing evidence for a key role of ABCA1 in this process. Impaired virus-cell entry correlated with the reorganisation of cholesterol-rich membrane microdomains (lipid rafts). The inhibitory effect could be reversed by an exogenous cholesterol supply, indicating that restriction of HCV infection was induced by changes of cholesterol content/distribution in membrane regions essential for virus-cell fusion. Stimulation of ABCA1 expression by GW3965 inhibited HCV infection of both human primary hepatocytes and isolated human liver slices. This study reveals that pharmacological stimulation of the ABCA1-dependent cholesterol efflux pathway disrupts membrane cholesterol homeostasis, leading to the inhibition of virus–cell fusion and thus HCV cell entry. Therefore besides other beneficial roles, ABCA1 might represent a potential target for HCV therapy.
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Affiliation(s)
- Simone Bocchetta
- Unité Hépacivirus et Immunité Innée, CNRS, UMR3569, Paris, France
- Dipartimento di Medicina Translazionale, Università del Piemonte Orientale, “Amedeo Avogadro”, Novara, Italy
| | - Patrick Maillard
- Unité Hépacivirus et Immunité Innée, CNRS, UMR3569, Paris, France
| | - Mami Yamamoto
- Unité Hépacivirus et Immunité Innée, CNRS, UMR3569, Paris, France
- Department of Biochemistry, Nihon University School of Medicine, Tokyo, Japan
| | - Claire Gondeau
- INSERM U1040, Institut de Recherche en Biothérapie, Hôpital Saint-Eloi, Montpellier, France
| | - Florian Douam
- Groupe de Recherche Dynamique Microbienne et Transmission virale, UMR CNRS 5557, Ecologie Microbienne, Villeurbanne, France
| | - Stéphanie Lebreton
- Unité Trafic Membranaire et Pathogenèse, Institut Pasteur, Paris, France
| | - Sylvie Lagaye
- Unité d’Hépatologie, AP-HP, Groupe Hospitalier Cochin-Hôtel Dieu, Paris, France
| | - Stanislas Pol
- Unité d’Hépatologie, AP-HP, Groupe Hospitalier Cochin-Hôtel Dieu, Paris, France
- Equipe Cycle Cellulaire, Régénération et Hépatopathies, INSERM U1016, CNRS UMR8104, Institut Cochin, Paris, France
| | - François Helle
- Laboratoire de Virologie, CHU Sud Amiens, Centre de Biologie Humaine, Amiens, France
| | - Wanee Plengpanich
- Dyslipidemia, Inflammation and Atherosclerosis in Metabolic Diseases, INSERM UMRS939, Paris, France
- Endocrinology and Metabolism Unit, Department of Medecine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
| | - Maryse Guérin
- Dyslipidemia, Inflammation and Atherosclerosis in Metabolic Diseases, INSERM UMRS939, Paris, France
| | - Maryline Bourgine
- Pathogénèse des Virus de l′Hépatite B, INSERM U845, Institut Pasteur, Paris, France
| | - Marie Louise Michel
- Pathogénèse des Virus de l′Hépatite B, INSERM U845, Institut Pasteur, Paris, France
| | - Dimitri Lavillette
- Groupe de Recherche Dynamique Microbienne et Transmission virale, UMR CNRS 5557, Ecologie Microbienne, Villeurbanne, France
| | - Philippe Roingeard
- INSERM U966, Université François-Rabelais and CHRU de Tours, Tours, France
| | - Wilfried le Goff
- Dyslipidemia, Inflammation and Atherosclerosis in Metabolic Diseases, INSERM UMRS939, Paris, France
| | - Agata Budkowska
- Unité Hépacivirus et Immunité Innée, CNRS, UMR3569, Paris, France
- * E-mail:
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Sharom FJ. Complex Interplay between the P-Glycoprotein Multidrug Efflux Pump and the Membrane: Its Role in Modulating Protein Function. Front Oncol 2014; 4:41. [PMID: 24624364 PMCID: PMC3939933 DOI: 10.3389/fonc.2014.00041] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 02/17/2014] [Indexed: 11/16/2022] Open
Abstract
Multidrug resistance in cancer is linked to expression of the P-glycoprotein multidrug transporter (Pgp, ABCB1), which exports many structurally diverse compounds from cells. Substrates first partition into the bilayer and then interact with a large flexible binding pocket within the transporter's transmembrane regions. Pgp has been described as a hydrophobic vacuum cleaner or an outwardly directed drug/lipid flippase. Recent X-ray crystal structures have shed some light on the nature of the drug-binding pocket and suggested routes by which substrates can enter it from the membrane. Detergents have profound effects on Pgp function, and several appear to be substrates. Biochemical and biophysical studies in vitro, some using purified reconstituted protein, have explored the effects of the membrane environment. They have demonstrated that Pgp is involved in a complex relationship with its lipid environment, which modulates the behavior of its substrates, as well as various functions of the protein, including ATP hydrolysis, drug binding, and drug transport. Membrane lipid composition and fluidity, phospholipid headgroup and acyl chain length all influence Pgp function. Recent studies focusing on thermodynamics and kinetics have revealed some important principles governing Pgp-lipid and substrate-lipid interactions, and how these affect drug-binding and transport. In some cells, Pgp is associated with cholesterol-rich microdomains, which may modulate its functions. The relationship between Pgp and cholesterol remains an open question; however, it clearly affects several aspects of its function in addition to substrate-membrane partitioning. The action of Pgp modulators appears to depend on their membrane permeability, and membrane fluidizers and surfactants reverse drug resistance, likely via an indirect mechanism. A detailed understanding of how the membrane affects Pgp substrates and Pgp's catalytic cycle may lead to new strategies to combat clinical drug resistance.
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Affiliation(s)
- Frances Jane Sharom
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
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13
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Martins IJ. Induction of NAFLD with Increased Risk of Obesity and Chronic Diseases in Developed Countries. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/ojemd.2014.44011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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14
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Lee SD, Thornton SJ, Sachs-Barrable K, Kim JH, Wasan KM. Evaluation of the contribution of the ATP binding cassette transporter, P-glycoprotein, to in vivo cholesterol homeostasis. Mol Pharm 2013; 10:3203-12. [PMID: 23750858 DOI: 10.1021/mp4002415] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
P-glycoprotein (Pgp, encoded by ABCB1, commonly known as MDR1), an ATP-dependent transporter with a broad range of hydrophobic drug substrates, has been associated with the in vitro intracellular transport of cholesterol; however, these findings have not been confirmed in vivo. In this manuscript we tested the contributions of Pgp to in vivo cholesterol homeostasis by comparing the cholesterol phenotype of wild type mice with mice lacking both murine isoforms of Pgp (Abcb1a(-/-)/1b(-/-)) by measuring cholesterol absorption, circulating cholesterol, and lipoprotein cholesterol profiles. The mice were fed diets containing normal or high levels of dietary fat (25% vs 45% kcal from fat) and cholesterol (0.02% vs 0.20% w/w) for 8 weeks to challenge their capacity to maintain homeostasis. There were no significant differences in cholesterol absorption, circulating cholesterol levels, and lipoprotein profiles between Pgp knockout and wild type mice fed matching diets. Compensatory shifts were observed in the activation of two key transcription factors involved in maintaining cholesterol balance, the Liver X Receptor and SREBP-2, which may have maintained the wild type phenotype in the knockout mice. Deletion of Pgp affected the molar composition of gallbladder bile, when the mice were fed diets containing high levels of dietary fat, cholesterol, or both. The mole fraction of bile salts was reduced in the gallbladder bile of Pgp knockout mice, while the mole fraction of cholesterol was increased. In this paper, we provide evidence that Pgp knockout mice maintain cholesterol homeostasis, even when challenged with high cholesterol diets. We suggest that the specific shifts in cholesterol regulatory networks identified in the jejunum and liver of the knockout mice may have compensated for the lack of Pgp. Our finding that Pgp knockout mice were unable to maintain gallbladder bile composition when challenged with high dietary fat and/or cholesterol compliments recent reports that Pgp may be a secondary bile salt export pump.
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Affiliation(s)
- Stephen D Lee
- Faculty of Pharmaceutical Sciences, University of British Columbia , 2405 Wesbrook Mall, Vancouver, BC, Canada V6T 1Z3
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15
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Le May C, Berger JM, Lespine A, Pillot B, Prieur X, Letessier E, Hussain MM, Collet X, Cariou B, Costet P. Transintestinal cholesterol excretion is an active metabolic process modulated by PCSK9 and statin involving ABCB1. Arterioscler Thromb Vasc Biol 2013; 33:1484-93. [PMID: 23559630 DOI: 10.1161/atvbaha.112.300263] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Transintestinal cholesterol excretion (TICE) is an alternate pathway to hepatobiliary secretion. Our study aimed at identifying molecular mechanisms of TICE. APPROACH AND RESULTS We studied TICE ex vivo in mouse and human intestinal explants, and in vivo after bile diversion and intestinal cannulation in mice. We provide the first evidence that both low-density lipoprotein (LDL) and high-density lipoprotein deliver cholesterol for TICE in human and mouse jejunal explants at the basolateral side. Proprotein convertase subtilisin kexin type 9 (PCSK9)(-/-) mice and intestinal explants show increased LDL-TICE, and acute injection of PCSK9 decreases TICE in vivo, suggesting that PCSK9 is a repressor of TICE. The acute repression was dependent on the LDL receptor (LDLR). Further, TICE was increased when mice were treated with lovastatin. These data point to an important role for LDLR in TICE. However, LDLR(-/-) mice showed increased intestinal LDL uptake, contrary to what is observed in the liver, and tended to have higher TICE. We interpret these data to suggest that there might be at least 2 mechanisms contributing to TICE; 1 involving LDL receptors and other unidentified mechanisms. Acute modulation of LDLR affects TICE, but chronic deficiency is compensated for most likely by the upregulation of the unknown mechanisms. Using mice deficient for apical multidrug active transporter ATP-binding cassette transporter B1 a and b, and its inhibitor, we show that these apical transporters contribute significantly to TICE. CONCLUSIONS TICE is operative in human jejunal explants. It is a metabolically active process that can be acutely regulated, inversely related to cholesterolemia, and pharmacologically activated by statins.
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Affiliation(s)
- Cédric Le May
- INSERM, UMR 1087, CNRS UMR 6291, Nantes F-44000, France
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16
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Zahid MN, Turek M, Xiao F, Thi VLD, Guérin M, Fofana I, Bachellier P, Thompson J, Delang L, Neyts J, Bankwitz D, Pietschmann T, Dreux M, Cosset FL, Grunert F, Baumert TF, Zeisel MB. The postbinding activity of scavenger receptor class B type I mediates initiation of hepatitis C virus infection and viral dissemination. Hepatology 2013; 57:492-504. [PMID: 23081796 DOI: 10.1002/hep.26097] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 09/22/2012] [Indexed: 02/06/2023]
Abstract
UNLABELLED Scavenger receptor class B type I (SR-BI) is a high-density lipoprotein (HDL) receptor highly expressed in the liver and modulating HDL metabolism. Hepatitis C virus (HCV) is able to directly interact with SR-BI and requires this receptor to efficiently enter into hepatocytes to establish productive infection. A complex interplay between lipoproteins, SR-BI and HCV envelope glycoproteins has been reported to take place during this process. SR-BI has been demonstrated to act during binding and postbinding steps of HCV entry. Although the SR-BI determinants involved in HCV binding have been partially characterized, the postbinding function of SR-BI remains largely unknown. To uncover the mechanistic role of SR-BI in viral initiation and dissemination, we generated a novel class of anti-SR-BI monoclonal antibodies that interfere with postbinding steps during the HCV entry process without interfering with HCV particle binding to the target cell surface. Using the novel class of antibodies and cell lines expressing murine and human SR-BI, we demonstrate that the postbinding function of SR-BI is of key impact for both initiation of HCV infection and viral dissemination. Interestingly, this postbinding function of SR-BI appears to be unrelated to HDL interaction but to be directly linked to its lipid transfer function. CONCLUSION Taken together, our results uncover a crucial role of the SR-BI postbinding function for initiation and maintenance of viral HCV infection that does not require receptor-E2/HDL interactions. The dissection of the molecular mechanisms of SR-BI-mediated HCV entry opens a novel perspective for the design of entry inhibitors interfering specifically with the proviral function of SR-BI.
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17
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Dao Thi VL, Granier C, Zeisel MB, Guérin M, Mancip J, Granio O, Penin F, Lavillette D, Bartenschlager R, Baumert TF, Cosset FL, Dreux M. Characterization of hepatitis C virus particle subpopulations reveals multiple usage of the scavenger receptor BI for entry steps. J Biol Chem 2012; 287:31242-57. [PMID: 22767607 PMCID: PMC3438956 DOI: 10.1074/jbc.m112.365924] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Revised: 06/29/2012] [Indexed: 12/21/2022] Open
Abstract
Hepatitis C virus (HCV) particles assemble along the very low density lipoprotein pathway and are released from hepatocytes as entities varying in their degree of lipid and apolipoprotein (apo) association as well as buoyant densities. Little is known about the cell entry pathway of these different HCV particle subpopulations, which likely occurs by regulated spatiotemporal processes involving several cell surface molecules. One of these molecules is the scavenger receptor BI (SR-BI), a receptor for high density lipoprotein that can bind to the HCV glycoprotein E2. By studying the entry properties of infectious virus subpopulations differing in their buoyant densities, we show that these HCV particles utilize SR-BI in a manifold manner. First, SR-BI mediates primary attachment of HCV particles of intermediate density to cells. These initial interactions involve apolipoproteins, such as apolipoprotein E, present on the surface of HCV particles, but not the E2 glycoprotein, suggesting that lipoprotein components in the virion act as host-derived ligands for important entry factors such as SR-BI. Second, we found that in contrast to this initial attachment, SR-BI mediates entry of HCV particles independent of their buoyant density. This function of SR-BI does not depend on E2/SR-BI interaction but relies on the lipid transfer activity of SR-BI, probably by facilitating entry steps along with other HCV entry co-factors. Finally, our results underscore a third function of SR-BI governed by specific residues in hypervariable region 1 of E2 leading to enhanced cell entry and depending on SR-BI ability to bind to E2.
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Affiliation(s)
- Viet Loan Dao Thi
- From the INSERM, U758, Human Virology Laboratory, EVIR team, Lyon, F-69007, France
- Ecole Normale Supérieure de Lyon, Lyon, F-69007, France
- Université de Lyon, UCB-Lyon1, Lyon, F-69007, France
- LabEx Ecofect, Université de Lyon, Lyon, F-69007, France
| | - Christelle Granier
- From the INSERM, U758, Human Virology Laboratory, EVIR team, Lyon, F-69007, France
- Ecole Normale Supérieure de Lyon, Lyon, F-69007, France
- Université de Lyon, UCB-Lyon1, Lyon, F-69007, France
- LabEx Ecofect, Université de Lyon, Lyon, F-69007, France
| | - Mirjam B. Zeisel
- INSERM, U748, 67000, Strasbourg, France
- Université de Strasbourg, 67000, Strasbourg, France
| | | | - Jimmy Mancip
- From the INSERM, U758, Human Virology Laboratory, EVIR team, Lyon, F-69007, France
- Ecole Normale Supérieure de Lyon, Lyon, F-69007, France
- Université de Lyon, UCB-Lyon1, Lyon, F-69007, France
- LabEx Ecofect, Université de Lyon, Lyon, F-69007, France
| | - Ophélia Granio
- From the INSERM, U758, Human Virology Laboratory, EVIR team, Lyon, F-69007, France
- Ecole Normale Supérieure de Lyon, Lyon, F-69007, France
- Université de Lyon, UCB-Lyon1, Lyon, F-69007, France
- LabEx Ecofect, Université de Lyon, Lyon, F-69007, France
| | - François Penin
- LabEx Ecofect, Université de Lyon, Lyon, F-69007, France
- Institut de Biologie et Chimie des Protéines, UMR 5086 CNRS, Université de Lyon, Lyon, F-69367, France
| | - Dimitri Lavillette
- From the INSERM, U758, Human Virology Laboratory, EVIR team, Lyon, F-69007, France
- Ecole Normale Supérieure de Lyon, Lyon, F-69007, France
- Université de Lyon, UCB-Lyon1, Lyon, F-69007, France
- LabEx Ecofect, Université de Lyon, Lyon, F-69007, France
| | - Ralf Bartenschlager
- the Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Im Neuenheimer Feld 345, 69120 Heidelberg, Germany, and
| | - Thomas F. Baumert
- INSERM, U748, 67000, Strasbourg, France
- Université de Strasbourg, 67000, Strasbourg, France
- Pôle Hepato-digestif, Hôpitaux Universitaires de Strasbourg, 67000, Strasbourg, France
| | - François-Loïc Cosset
- From the INSERM, U758, Human Virology Laboratory, EVIR team, Lyon, F-69007, France
- Ecole Normale Supérieure de Lyon, Lyon, F-69007, France
- Université de Lyon, UCB-Lyon1, Lyon, F-69007, France
- LabEx Ecofect, Université de Lyon, Lyon, F-69007, France
| | - Marlène Dreux
- From the INSERM, U758, Human Virology Laboratory, EVIR team, Lyon, F-69007, France
- Ecole Normale Supérieure de Lyon, Lyon, F-69007, France
- Université de Lyon, UCB-Lyon1, Lyon, F-69007, France
- LabEx Ecofect, Université de Lyon, Lyon, F-69007, France
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18
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Orsoni A, Villard EF, Bruckert E, Robillard P, Carrie A, Bonnefont-Rousselot D, Chapman MJ, Dallinga-Thie GM, Le Goff W, Guerin M. Impact of LDL apheresis on atheroprotective reverse cholesterol transport pathway in familial hypercholesterolemia. J Lipid Res 2012; 53:767-75. [PMID: 22338009 DOI: 10.1194/jlr.m024141] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In familial hypercholesterolemia (FH), low HDL cholesterol (HDL-C) levels are associated with functional alterations of HDL particles that reduce their capacity to mediate the reverse cholesterol transport (RCT) pathway. The objective of this study was to evaluate the consequences of LDL apheresis on the efficacy of the RCT pathway in FH patients. LDL apheresis markedly reduced abnormal accelerated cholesteryl ester transfer protein (CETP)-mediated cholesteryl ester (CE) transfer from HDL to LDL, thus reducing their CE content. Equally, we observed a major decrease (-53%; P < 0.0001) in pre-β1-HDL levels. The capacity of whole plasma to mediate free cholesterol efflux from human macrophages was reduced (-15%; P < 0.02) following LDL apheresis. Such reduction resulted from a marked decrease in the ABCA1-dependent efflux (-71%; P < 0.0001) in the scavenger receptor class B type I-dependent efflux (-21%; P < 0.0001) and in the ABCG1-dependent pathway (-15%; P < 0.04). However, HDL particles isolated from FH patients before and after LDL apheresis displayed a similar capacity to mediate cellular free cholesterol efflux or to deliver CE to hepatic cells. We demonstrate that rapid removal of circulating lipoprotein particles by LDL apheresis transitorily reduces RCT. However, LDL apheresis is without impact on the intrinsic ability of HDL particles to promote either cellular free cholesterol efflux from macrophages or to deliver CE to hepatic cells.
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19
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Frisdal E, Lesnik P, Olivier M, Robillard P, Chapman MJ, Huby T, Guerin M, Le Goff W. Interleukin-6 protects human macrophages from cellular cholesterol accumulation and attenuates the proinflammatory response. J Biol Chem 2011; 286:30926-30936. [PMID: 21757719 DOI: 10.1074/jbc.m111.264325] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cholesterol-laden monocyte-derived macrophages are phagocytic cells characteristic of early and advanced atherosclerotic lesions. Interleukin-6 (IL-6) is a macrophage secretory product that is abundantly expressed in atherosclerotic plaques but whose precise role in atherogenesis is unclear. The capacity of macrophages to clear apoptotic cells, through the efferocytosis mechanism, as well as to reduce cellular cholesterol accumulation contributes to prevent plaque progression and instability. By virtue of its capacity to promote cellular cholesterol efflux from phagocyte-macrophages, ABCA1 was reported to reduce atherosclerosis. We demonstrated that lipid loading in human macrophages was accompanied by a strong increase of IL-6 secretion. Interestingly, IL-6 markedly induced ABCA1 expression and enhanced ABCA1-mediated cholesterol efflux from human macrophages to apoAI. Stimulation of ABCA1-mediated cholesterol efflux by IL-6 was, however, abolished by selective inhibition of the Jak-2/Stat3 signaling pathway. In addition, we observed that the expression of molecules described to promote efferocytosis, i.e. c-mer proto-oncogene-tyrosine kinase, thrombospondin-1, and transglutaminase 2, was significantly induced in human macrophages upon treatment with IL-6. Consistent with these findings, IL-6 enhanced the capacity of human macrophages to phagocytose apoptotic cells; moreover, we observed that IL-6 stimulates the ABCA1-mediated efflux of cholesterol derived from the ingestion of free cholesterol-loaded apoptotic macrophages. Finally, the treatment of human macrophages with IL-6 led to the establishment of an anti-inflammatory cytokine profile, characterized by an increased secretion of IL-4 and IL-10 together with a decrease of that of IL-1β. Taken together, our results indicate that IL-6 favors the elimination of excess cholesterol in human macrophages and phagocytes by stimulation of ABCA1-mediated cellular free cholesterol efflux and attenuates the macrophage proinflammatory phenotype. Thus, high amounts of IL-6 secreted by lipid laden human macrophages may constitute a protective response from macrophages to prevent accumulation of cytotoxic-free cholesterol. Such a cellular recycling of free cholesterol may contribute to reduce both foam cell formation and the accumulation of apoptotic bodies as well as intraplaque inflammation in atherosclerotic lesions.
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Affiliation(s)
- Eric Frisdal
- INSERM, UMR_S939, Dyslipidemia, Inflammation, and Atherosclerosis in Metabolic Diseases, and the ICAN Institute of CardioMetabolism and Nutrition F-75013 and the Université Pierre et Marie Curie Paris 06, UMR_S939, F-75005, Paris, France
| | - Philippe Lesnik
- INSERM, UMR_S939, Dyslipidemia, Inflammation, and Atherosclerosis in Metabolic Diseases, and the ICAN Institute of CardioMetabolism and Nutrition F-75013 and the Université Pierre et Marie Curie Paris 06, UMR_S939, F-75005, Paris, France
| | - Maryline Olivier
- INSERM, UMR_S939, Dyslipidemia, Inflammation, and Atherosclerosis in Metabolic Diseases, and the ICAN Institute of CardioMetabolism and Nutrition F-75013 and the Université Pierre et Marie Curie Paris 06, UMR_S939, F-75005, Paris, France
| | - Paul Robillard
- INSERM, UMR_S939, Dyslipidemia, Inflammation, and Atherosclerosis in Metabolic Diseases, and the ICAN Institute of CardioMetabolism and Nutrition F-75013 and the Université Pierre et Marie Curie Paris 06, UMR_S939, F-75005, Paris, France
| | - M John Chapman
- INSERM, UMR_S939, Dyslipidemia, Inflammation, and Atherosclerosis in Metabolic Diseases, and the ICAN Institute of CardioMetabolism and Nutrition F-75013 and the Université Pierre et Marie Curie Paris 06, UMR_S939, F-75005, Paris, France
| | - Thierry Huby
- INSERM, UMR_S939, Dyslipidemia, Inflammation, and Atherosclerosis in Metabolic Diseases, and the ICAN Institute of CardioMetabolism and Nutrition F-75013 and the Université Pierre et Marie Curie Paris 06, UMR_S939, F-75005, Paris, France
| | - Maryse Guerin
- INSERM, UMR_S939, Dyslipidemia, Inflammation, and Atherosclerosis in Metabolic Diseases, and the ICAN Institute of CardioMetabolism and Nutrition F-75013 and the Université Pierre et Marie Curie Paris 06, UMR_S939, F-75005, Paris, France
| | - Wilfried Le Goff
- INSERM, UMR_S939, Dyslipidemia, Inflammation, and Atherosclerosis in Metabolic Diseases, and the ICAN Institute of CardioMetabolism and Nutrition F-75013 and the Université Pierre et Marie Curie Paris 06, UMR_S939, F-75005, Paris, France.
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20
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Do TM, Ouellet M, Calon F, Chimini G, Chacun H, Farinotti R, Bourasset F. Direct evidence of abca1-mediated efflux of cholesterol at the mouse blood-brain barrier. Mol Cell Biochem 2011; 357:397-404. [PMID: 21660464 DOI: 10.1007/s11010-011-0910-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 05/28/2011] [Indexed: 02/07/2023]
Abstract
We investigated the expression and function of Abca1 in wild-type C57BL/6, abca1(+/+), and abca1(-/-) mice brain capillaries forming the blood-brain barrier (BBB). We first demonstrated by quantitative RT-PCR and Western immunoblot that Abca1 was expressed and enriched in the wild-type mouse brain capillaries. In abca1(-/-) mice, we reported that the lack of Abca1 resulted in an 1.6-fold increase of the Abcg4 expression level compared to abca1(+/+) mice. Next, using the in situ brain perfusion technique, we showed that the [(3)H]cholesterol brain uptake clearance (Cl(up), μl/s/g brain), was significantly increased (107%) in abca1(-/-) mice compared to abca1(+/+) mice, meaning that the deficiency of Abca1 conducted to a significant decrease of the cholesterol efflux at the BBB level. In addition, the co-perfusion of probucol (Abca1 inhibitor) with [(3)H]cholesterol resulted in an increase of [(3)H]cholesterol Cl(up) (115%) in abca1(+/+) but not in abca1(-/-) mice, meaning that probucol inhibited selectively the efflux function of Abca1. In conclusion, our results demonstrated that Abca1 was expressed in the mouse brain capillaries and that Abca1 functions as an efflux transporter through the mouse BBB.
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Affiliation(s)
- Tuan Minh Do
- Laboratory of Clinical Pharmacy, EA4123, University of Paris Sud 11, 5 rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France
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21
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Julia Z, Duchene E, Fournier N, Bellanger N, Chapman MJ, Le Goff W, Guerin M. Postprandial lipemia enhances the capacity of large HDL2 particles to mediate free cholesterol efflux via SR-BI and ABCG1 pathways in type IIB hyperlipidemia. J Lipid Res 2010; 51:3350-8. [DOI: 10.1194/jlr.p009746] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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22
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The relationships of ABCB1 3435C>T and CYP2B6 516G>T with high-density lipoprotein cholesterol in HIV-infected patients receiving Efavirenz. Clin Pharmacol Ther 2009; 86:204-11. [PMID: 19474786 DOI: 10.1038/clpt.2009.78] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are associated with a favorable increase in high-density lipoprotein cholesterol (HDL-c) level. Isolated studies have found a direct correlation between efavirenz (EFV) exposure and HDL-c level changes. Here we explore the impact that drug disposition variants associated with EFV exposure have on changes in HDL-c level. Seventy-six patients on first-line EFV-based regimens were genotyped for CYP2B6 516G>T and ABCB1 3435C>T. There was a 37% increase (+0.32 mmol/l, P < 0.001) in mean HDL-c level over 48 weeks, and this was univariately associated with gender (male +0.26 mmol/l, female +0.55 mmol/l; P = 0.03), ABCB1 3435C>T (CC +0.26 mmol/l, CT +0.16 mmol/l, TT +0.54 mmol/l; P(ANOVA) = 0.003) and CYP2B6 516 G>T (GG +0.27 mmol/l, GT +0.29 mmol/l, TT +0.72 mmol/l; P(ANOVA) = 0.08). There was a significant association between the cumulative number of predictive genotypes (CYP2B6 516TT or ABCB1 3435TT) and mean HDL-c level change: (group 0 +0.20 mmol/l, group 1 +0.47 mmol/l, group 2 +1.00 mmol/l; P(ANOVA) < 0.0001). These findings need to be validated in independent cohorts.
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23
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Dreux M, Dao Thi VL, Fresquet J, Guérin M, Julia Z, Verney G, Durantel D, Zoulim F, Lavillette D, Cosset FL, Bartosch B. Receptor complementation and mutagenesis reveal SR-BI as an essential HCV entry factor and functionally imply its intra- and extra-cellular domains. PLoS Pathog 2009; 5:e1000310. [PMID: 19229312 PMCID: PMC2636890 DOI: 10.1371/journal.ppat.1000310] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 01/23/2009] [Indexed: 12/11/2022] Open
Abstract
HCV entry into cells is a multi-step and slow process. It is believed that the
initial capture of HCV particles by glycosaminoglycans and/or lipoprotein
receptors is followed by coordinated interactions with the scavenger receptor
class B type I (SR-BI), a major receptor of high-density lipoprotein (HDL), the
CD81 tetraspanin, and the tight junction protein Claudin-1, ultimately leading
to uptake and cellular penetration of HCV via low-pH endosomes.
Several reports have indicated that HDL promotes HCV entry through interaction
with SR-BI. This pathway remains largely elusive, although it was shown that HDL
neither associates with HCV particles nor modulates HCV binding to SR-BI. In
contrast to CD81 and Claudin-1, the importance of SR-BI has only been addressed
indirectly because of lack of cells in which functional complementation assays
with mutant receptors could be performed. Here we identified for the first time
two cell types that supported HCVpp and HCVcc entry upon ectopic SR-BI
expression. Remarkably, the undetectable expression of SR-BI in rat hepatoma
cells allowed unambiguous investigation of human SR-BI functions during HCV
entry. By expressing different SR-BI mutants in either cell line, our results
revealed features of SR-BI intracellular domains that influence HCV infectivity
without affecting receptor binding and stimulation of HCV entry induced by
HDL/SR-BI interaction. Conversely, we identified positions of SR-BI ectodomain
that, by altering HCV binding, inhibit entry. Finally, we characterized
alternative ectodomain determinants that, by reducing SR-BI cholesterol uptake
and efflux functions, abolish HDL-mediated infection-enhancement. Altogether, we
demonstrate that SR-BI is an essential HCV entry factor. Moreover, our results
highlight specific SR-BI determinants required during HCV entry and
physiological lipid transfer functions hijacked by HCV to favor infection. More than 180 million people are chronically infected by hepatitis C virus (HCV),
a leading cause of liver failure and cancer, stimulating the need to fully
define the biology of HCV infection for developing novel and effective
therapeutics. During the first steps of infection, the virus is taken up and
penetrates hepatocytes. HCV entry is thought to be a coordinated multi-step
process mediated by specific factors, including CD81, Claudin-1, and the
scavenger receptor BI (SR-BI). Whereas the involvement of CD81 and Claudin-1 was
demonstrated by rendering susceptible cells that are otherwise refractory, SR-BI
complementation assays were lacking, raising questions as to its functions
during HCV entry. Here, we identify one hepatoma rat cell line, in which SR-BI
complementation assay and targeted mutagenesis could be performed. We therefore
demonstrate that SR-BI is an essential HCV entry factor. Our results shed light
on SR-BI intracellular domain functions in HCV entry, and, further, emphasize
the remarkable capacity of HCV to hijack the lipid transfer function of SR-BI,
hence favoring infection.
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Affiliation(s)
- Marlène Dreux
- Université de Lyon, UCB-Lyon1, IFR128; INSERM, U758; Ecole
Normale Supérieure de Lyon, Lyon, France
| | - Viet Loan Dao Thi
- Université de Lyon, UCB-Lyon1, IFR128; INSERM, U758; Ecole
Normale Supérieure de Lyon, Lyon, France
| | - Judith Fresquet
- Université de Lyon, UCB-Lyon1, IFR128; INSERM, U758; Ecole
Normale Supérieure de Lyon, Lyon, France
| | | | | | - Géraldine Verney
- Université de Lyon, UCB-Lyon1, IFR128; INSERM, U758; Ecole
Normale Supérieure de Lyon, Lyon, France
| | - David Durantel
- Université de Lyon, UCB-Lyon1, IFR62; INSERM, U871; Hospices
civils de Lyon (HCL), Lyon, France
| | - Fabien Zoulim
- Université de Lyon, UCB-Lyon1, IFR62; INSERM, U871; Hospices
civils de Lyon (HCL), Lyon, France
| | - Dimitri Lavillette
- Université de Lyon, UCB-Lyon1, IFR128; INSERM, U758; Ecole
Normale Supérieure de Lyon, Lyon, France
| | - François-Loïc Cosset
- Université de Lyon, UCB-Lyon1, IFR128; INSERM, U758; Ecole
Normale Supérieure de Lyon, Lyon, France
- * E-mail:
| | - Birke Bartosch
- Université de Lyon, UCB-Lyon1, IFR128; INSERM, U758; Ecole
Normale Supérieure de Lyon, Lyon, France
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Eckford PDW, Sharom FJ. Interaction of the P-glycoprotein multidrug efflux pump with cholesterol: effects on ATPase activity, drug binding and transport. Biochemistry 2009; 47:13686-98. [PMID: 19049391 DOI: 10.1021/bi801409r] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Resistance to a broad spectrum of structurally diverse chemotherapeutic drugs (multidrug resistance; MDR) is a major impediment to the treatment of cancer. One cause of MDR is the expression at the tumor cell surface of P-glycoprotein (Pgp), which functions as an ATP-powered multidrug efflux pump. Since Pgp interacts with its substrates after they partition into the lipid bilayer, changes in membrane physicochemical properties may have substantial effects on its functional activity. Various interactions between cholesterol and Pgp have been suggested, including a role for the protein in transbilayer movement of cholesterol. We have characterized several aspects of Pgp-cholesterol interactions, and found that some of the previously reported effects of cholesterol result from inhibition of Pgp ATPase activity by the cholesterol-extracting reagent, methyl-beta-cyclodextrin. The presence of cholesterol in the bilayer modulated the basal and drug-stimulated ATPase activity of reconstituted Pgp in a modest fashion. Both the ability of drugs to bind to the protein and the drug transport and phospholipid flippase functions of Pgp were also affected by cholesterol. The effects of cholesterol on drug binding affinity were unrelated to the size of the compound. Increasing cholesterol content greatly altered the partitioning of hydrophobic drug substrates into the membrane, which may account for some of the observed effects of cholesterol on Pgp-mediated drug transport. Pgp does not appear to mediate the flip-flop of a fluorescent cholesterol analogue across the bilayer. Cholesterol likely modulates Pgp function via effects on drug-membrane partitioning and changes in the local lipid environment of the protein.
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Affiliation(s)
- Paul D W Eckford
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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25
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Shu Y, Liu H. Reversal of P-glycoprotein-mediated multidrug resistance by cholesterol derived from low density lipoprotein in a vinblastine-resistant human lymphoblastic leukemia cell line. Biochem Cell Biol 2008; 85:638-46. [PMID: 17901905 DOI: 10.1139/o07-065] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
P-glycoprotein (P-gp) is believed to be one of the most common causes of multidrug resistance (MDR) in chemotherapy. Studies have shown that the biosynthesis of cholesterol and cholesterol esters interfere with the function of P-gp. Since low density lipoprotein (LDL) carries a large amount of cholesterol, we investigated the effect of cholesterol derived from LDL on a line of human lymphoblastic leukemia MDR cells, CEM/VLB. Our results demonstrated that, in addition to increased cytotoxicity, the uptake of vinblastine in CEM/VLB cells increased, and LDL subsequently increased the intracellular vinblastine concentrations retained by CEM/VLB cells. The cholesterol levels in the membrane of the MDR cells were restored, while LDL significantly decreased the P-gp-associated ATPase activity. Current studies have shown that LDL leads to the resensitization of CEM/VLB cells to cytotoxic agents, likely through the restoration of cholesterol and reduction of P-gp-associated ATPase in the cell membrane.
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Affiliation(s)
- Yu Shu
- School of Pharmacy, Memorial University of Newfoundland, 300 Prince Philip Drive, St. John's, NL A1B 3V6, [corrected] Canada
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26
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De Rosa MF, Ackerley C, Wang B, Ito S, Clarke DM, Lingwood C. Inhibition of multidrug resistance by adamantylgb3, a globotriaosylceramide analog. J Biol Chem 2007; 283:4501-11. [PMID: 18003606 DOI: 10.1074/jbc.m705473200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Multidrug resistance (MDR) via the ABC drug transporter (ABCB1), P-glycoprotein (P-gp/MDR1) overexpression, is a major obstacle in cancer chemotherapy. Many inhibitors reverse MDR but, like cyclosporin A (CsA), have significant toxicities. MDR1 is also a translocase that flips glucosylceramide inside the Golgi to enhance neutral glycosphingolipid (GSL) synthesis. We observed partial MDR1/globotriaosylceramide (Gb3) cell surface co-localization, and GSL removal depleted cell surface MDR1. MDR1 may therefore interact with GSLs. AdamantylGb3, a water-soluble Gb3 mimic, but not other GSL analogs, reversed MDR1-MDCK cell drug resistance. Cell surface MDR1 was up-regulated 1 h after treatment with CsA or adaGb3, but at 72 h, cell surface expression was lost. Intracellular MDR1 accumulated throughout, suggesting long term defects in plasma membrane MDR1 trafficking. AdaGb3 or CsA rapidly reduced rhodamine 123 cellular efflux. MDR1 also mediates gastrointestinal epithelial drug efflux, restricting oral bioavailability. Vinblastine apical-to-basal transport in polarized human intestinal C2BBe1 cells was significantly increased when adaGb3 was added to both sides, or to the apical side only, comparable with verapamil, a standard MDR1 inhibitor. Disulfide cross-linking of mutant MDR1s showed no binding of adaGb3 to the MDR1 verapamil/cyclosporin-binding site between surface proximal helices of transmembrane segments (TM) 6 and TM7, but rather to an adjacent site nearer the center of TM6 and the TM7 extracellular face, i.e. close to the bilayer leaflet interface. Verotoxin-mediated Gb3 endocytosis also up-regulated total MDR1 and inhibited drug efflux. Thus, a functional interplay between membrane Gb3 and MDR1 provides a more physiologically based approach to MDR1 regulation to increase the bioavailability of chemotherapeutic drugs.
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Affiliation(s)
- María Fabiana De Rosa
- Division of Molecular Structure and Function, Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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27
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Connelly-Smith L, Pattinson J, Grundy M, Shang S, Seedhouse C, Russell N, Pallis M. P-glycoprotein is downregulated in KG1a-primitive leukemia cells by LDL cholesterol deprivation and by HMG-CoA reductase inhibitors. Exp Hematol 2007; 35:1793-800. [PMID: 17923246 DOI: 10.1016/j.exphem.2007.07.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 07/19/2007] [Accepted: 07/23/2007] [Indexed: 01/11/2023]
Abstract
OBJECTIVE P-glycoprotein (pgp) is a membrane transporter encoded by the multidrug resistance (MDR1, ABCB1) gene. Pgp is a poor prognostic factor in elderly patients with acute myeloid leukemia (AML). In addition to its role in drug efflux, pgp has been implicated in cellular cholesterol homeostasis. We investigated the effects of exogenous cholesterol removal on pgp expression and function. METHODS KG1a drug-naïve, primitive leukemia cells were cultured in serum-free medium with or without the addition of low-density lipoprotein (LDL) cholesterol. After 72 hours, pgp expression and function was assessed by flow cytometry and total cholesterol content of the KG1a cells was determined by the Amplex Red cholesterol assay. The addition of clinically available cholesterol-lowering agents, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors to KG1a cells was also assessed. RESULTS There was a 39% (SEM = 8.3%; p = 0.03) decrease in pgp protein expression after 3 days of serum-free culture. The decrease was also observed at the message and functional levels. In the presence of low-density lipoprotein cholesterol, pgp expression was restored to 86% of the basal value. Addition of a HMG-CoA reductase inhibitor to KG1a cells resulted in an additional 26% (lovastatin, p = 0.03) and 16% (pravastatin, p = 0.05) reduction in pgp, respectively. Furthermore, toxicity of the pgp substrate drug daunorubicin was enhanced following lovastatin preculture (p = 0.04). CONCLUSION LDL cholesterol contributes to pgp expression and chemoresistance in primitive leukemia cells. Use of HMG-CoA reductase inhibitors may be of clinical value in lowering pgp expression in AML.
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Orlowski S, Coméra C, Tercé F, Collet X. Lipid rafts: dream or reality for cholesterol transporters? EUROPEAN BIOPHYSICS JOURNAL: EBJ 2007; 36:869-85. [PMID: 17576551 DOI: 10.1007/s00249-007-0193-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Revised: 05/11/2007] [Accepted: 05/15/2007] [Indexed: 01/12/2023]
Abstract
As a key constituent of the cell membranes, cholesterol is an endogenous component of mammalian cells of primary importance, and is thus subjected to highly regulated homeostasis at the cellular level as well as at the level of the whole body. This regulation requires adapted mechanisms favoring the handling of cholesterol in aqueous compartments, as well as its transfer into or out of membranes, involving membrane proteins. A membrane exhibits functional properties largely depending on its lipid composition and on its structural organization, which very often involves cholesterol-rich microdomains. Then there is the appealing possibility that cholesterol may regulate its own transmembrane transport at a purely functional level, independently of any transcriptional regulation based on cholesterol-sensitive nuclear factors controling the expression level of lipid transport proteins. Indeed, the main cholesterol "transporters" presently believed to mediate for instance the intestinal absorption of cholesterol, that are SR-BI, NPC1L1, ABCA1, ABCG1, ABCG5/G8 and even P-glycoprotein, all present privileged functional relationships with membrane cholesterol-containing microdomains. In particular, they all more or less clearly induce membrane disorganization, supposed to facilitate cholesterol exchanges with the close aqueous medium. The actual lipid substrates handled by these transporters are not yet unambiguously determined, but they likely concern the components of membrane microdomains. Conversely, raft alterations may provide specific modulations of the transporter activities, as well as they can induce indirect effects via local perturbations of the membrane. Finally, these cholesterol transporters undergo regulated intracellular trafficking, with presumably some relationships to rafts which remain to be clarified.
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Affiliation(s)
- Stéphane Orlowski
- SB2SM/IBTS and URA 2096 CNRS, CEA, Centre de Saclay, 91191, Gif-sur-Yvette cedex, France.
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Agrawal S, Febbraio M, Podrez E, Cathcart MK, Stark GR, Chisolm GM. Signal transducer and activator of transcription 1 is required for optimal foam cell formation and atherosclerotic lesion development. Circulation 2007; 115:2939-47. [PMID: 17533179 DOI: 10.1161/circulationaha.107.696922] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Signal transducer and activator of transcription 1 (Stat1) potently regulates gene expression after stimulation by certain cytokines involved in tumorigenesis and host defenses. The present study investigated a novel role for Stat1 in foam cell formation and atherosclerosis. METHODS AND RESULTS Inhibition of Stat1 activity by a Stat1-specific DNA "decoy" oligomer transfected into differentiated human THP-1 cells, and deficiency of stat1 in mouse macrophages significantly inhibited foam cell formation assessed by lipid staining and cholesteryl ester accumulation compared with control cells. The mechanism of Stat1 regulation of foam cell formation was uniquely dependent on the scavenger receptor CD36. Blunted Stat1 activity and stat1 deficiency significantly decreased expression of CD36 but not of scavenger receptor-A compared with controls, as assessed by immunoblotting and flow cytometry. Deficiency of CD36 but not scavenger receptor-A in mouse macrophages removed any dependency of foam cell formation on Stat1. In an intraperitoneal model of foam cell formation in which foam cells form in vivo independently of the model ligands used in vitro, stat1 deficiency significantly inhibited foam cell formation and CD36 expression. Transplantation of bone marrow from apolipoprotein e-/- x stat1-/- mice into lethally irradiated, atherosclerosis-susceptible apolipoprotein e-/- recipients significantly reduced both en face aortic lesion coverage and aortic root lesions compared with recipients of bone marrow from genetically matched apolipoprotein e-/- mice. CONCLUSIONS Stat1 regulates CD36 expression and foam cell formation in macrophages in vitro; the Stat1 regulation of foam cell formation requires CD36. The regulation of CD36 expression by Stat1 may be important in other pathophysiological CD36-dependent events. Stat1 deficiency reduces atherosclerosis in an apolipoprotein e-/- atherosclerosis-susceptible bone marrow transplantation model.
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Affiliation(s)
- Sudesh Agrawal
- Department of Cell Biology, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195, USA
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30
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Pál A, Méhn D, Molnár E, Gedey S, Mészáros P, Nagy T, Glavinas H, Janáky T, von Richter O, Báthori G, Szente L, Krajcsi P. Cholesterol potentiates ABCG2 activity in a heterologous expression system: improved in vitro model to study function of human ABCG2. J Pharmacol Exp Ther 2007; 321:1085-94. [PMID: 17347325 DOI: 10.1124/jpet.106.119289] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
ABCG2, a transporter of the ATP-binding cassette family, is known to play a prominent role in the absorption, distribution, metabolism, and excretion of xenobiotics. Drug-transporter interactions are commonly screened by high-throughput systems using transfected insect and/or human cell lines. The determination of ABCG2-ATPase activity is one method to identify ABCG2 substrate and inhibitors. We demonstrate that the ATPase activities of the human ABCG2 transfected Sf9 cell membranes (MXR-Sf9) and ABCG2-overexpressing human cell membranes (MXR-M) differ. Variation due to disparity in the glycosylation level of the protein had no effect on the transporter. The influence of cholesterol on ABCG2-ATPase activity was investigated because the lipid compositions of insect and human cells are largely different from each other. Differences in cholesterol content, shown by cholesterol loading and depletion experiments, conferred the difference in stimulation of basal ABCG2-ATPase of the two cell membranes. Basal ABCG2-ATPase activity could be stimulated by sulfasalazine, prazosin, and topotecan, known substrates of ABCG2 in cholesterol-loaded MXR-Sf9 and MXR-M cell membranes. In contrast, ABCG2-ATPase could not be stimulated in MXR-Sf9 or in cholesterol-depleted MXR-M membranes. Moreover, cholesterol loading significantly improved the drug transport into inside-out membrane vesicles prepared from MXR-Sf9 cells. MXR-M and cholesterol-loaded MXR-Sf9 cell membranes displayed similar ABCG2-ATPase activity and vesicular transport. Our study indicates an essential role of membrane cholesterol for the function of ABCG2.
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Affiliation(s)
- A Pál
- SOLVO Biotechnology, Central Hungarian Innovations Center, Gyár u. 2., H-2040 Budaörs, Hungary
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Lin T, Islam O, Heese K. ABC transporters, neural stem cells and neurogenesis – a different perspective. Cell Res 2006; 16:857-71. [PMID: 17088897 DOI: 10.1038/sj.cr.7310107] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Stem cells intrigue. They have the ability to divide exponentially, recreate the stem cell compartment, as well as create differentiated cells to generate tissues. Therefore, they should be natural candidates to provide a renewable source of cells for transplantation applied in regenerative medicine. Stem cells have the capacity to generate specific tissues or even whole organs like the blood, heart, or bones. A subgroup of stem cells, the neural stem cells (NSCs), is characterized as a self-renewing population that generates neurons and glia of the developing brain. They can be isolated, genetically manipulated and differentiated in vitro and reintroduced into a developing, adult or a pathologically altered central nervous system. NSCs have been considered for use in cell replacement therapies in various neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease. Characterization of genes with tightly controlled expression patterns during differentiation represents an approach to understanding the regulation of stem cell commitment. The regulation of stem cell biology by the ATP-binding cassette (ABC) transporters has emerged as an important new field of investigation. As a major focus of stem cell research is in the manipulation of cells to enable differentiation into a targeted cell population; in this review, we discuss recent literatures on ABC transporters and stem cells, and propose an integrated view on the role of the ABC transporters, especially ABCA2, ABCA3, ABCB1 and ABCG2, in NSCs' proliferation, differentiation and regulation, along with comparisons to that in hematopoietic and other stem cells.
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Affiliation(s)
- Tingting Lin
- Department of Molecular and Cell Biology, School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
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32
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Pennings M, Meurs I, Ye D, Out R, Hoekstra M, Van Berkel TJC, Van Eck M. Regulation of cholesterol homeostasis in macrophages and consequences for atherosclerotic lesion development. FEBS Lett 2006; 580:5588-96. [PMID: 16935283 DOI: 10.1016/j.febslet.2006.08.022] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 07/28/2006] [Accepted: 08/06/2006] [Indexed: 11/25/2022]
Abstract
Foam cell formation due to excessive accumulation of cholesterol by macrophages is a pathological hallmark of atherosclerosis. Macrophages cannot limit the uptake of cholesterol and therefore depend on cholesterol efflux pathways for preventing their transformation into foam cells. Several ABC-transporters, including ABCA1 and ABCG1, facilitate the efflux of cholesterol from macrophages. These transporters, however, also affect membrane lipid asymmetry which may have important implications for cellular endocytotic pathways. We propose that in addition to the generally accepted role of these ABC-transporters in the prevention of foam cell formation by induction of cholesterol efflux from macrophages, they also influence the macrophage endocytotic uptake.
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Affiliation(s)
- Marieke Pennings
- Division of Biopharmaceutics, Leiden/Amsterdam Center for Drug Research, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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Leon C, Wasan KM, Sachs-Barrable K, Johnston TP. Acute P-407 administration to mice causes hypercholesterolemia by inducing cholesterolgenesis and down-regulating low-density lipoprotein receptor expression. Pharm Res 2006; 23:1597-607. [PMID: 16783477 DOI: 10.1007/s11095-006-0276-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Accepted: 02/23/2006] [Indexed: 10/24/2022]
Abstract
PURPOSE Poloxamer 407 (P-407) is a chemical that induces a dose-controlled dyslipidemia in mice. Our aim was to determine the acute effects of P-407 treatment on the mechanisms that influence hepatic cholesterol homeostasis. METHODS We measured lipid levels in plasma and liver samples from control and P-407-treated mice (24 h post-i.p. injection of 0.5 g kg(-1) of P-407 or saline for the control mice). We measured acyl-coenzyme A:cholesterol acyltransferase (ACAT) and 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activities in liver microsomes. The protein expression of ACAT2, scavenger receptor class B, type I (SR-BI), ATP-binding cassette transporter A1 (ABCA1), ATP-binding cassette transporter G8 (ABCG8), low-density lipoprotein receptor (LDLr), and actin was measured by immunoblot. RESULTS We found an increase in plasma cholesterol and triglyceride levels as well as increased hepatic cholesteryl esters (CE) in P-407-treated mice. The hepatic ACAT microsomal activity and ACAT2 protein expression were not altered by P-407. The protein expression of the LDLr was decreased in the livers of P-407-treated mice. This decrease was specific, because the expression of the SR-BI was unchanged. The P-407-induced hypercholesterolemia was accounted for by increased activity and protein expression of HMG-CoA reductase. ATP-binding cassette transporters A1 and G8 protein expression were not significantly different in P-407-treated mice compared to controls. CONCLUSIONS The increased hepatic CE levels, following P-407 treatment, was neither related to an up-regulation of ACAT2 nor enhanced SR-BI expression. Hypercholesterolemia was associated with an up-regulation of both the protein expression and activity of HMG-CoA reductase and decreased LDLr expression.
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Affiliation(s)
- Carlos Leon
- Division of Pharmaceutics and Biopharmaceutics, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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