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Chiang CL, Ma Y, Hou YC, Pan J, Chen SY, Chien MH, Zhang ZX, Hsu WH, Wang X, Zhang J, Li H, Sun L, Fallen S, Lee I, Chen XY, Chu YS, Zhang C, Cheng TS, Jiang W, Kim BYS, Reategui E, Lee R, Yuan Y, Liu HC, Wang K, Hsiao M, Huang CYF, Shan YS, Lee AS, James Lee L. Dual targeted extracellular vesicles regulate oncogenic genes in advanced pancreatic cancer. Nat Commun 2023; 14:6692. [PMID: 37872156 PMCID: PMC10593751 DOI: 10.1038/s41467-023-42402-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 10/10/2023] [Indexed: 10/25/2023] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) tumours carry multiple gene mutations and respond poorly to treatments. There is currently an unmet need for drug carriers that can deliver multiple gene cargoes to target high solid tumour burden like PDAC. Here, we report a dual targeted extracellular vesicle (dtEV) carrying high loads of therapeutic RNA that effectively suppresses large PDAC tumours in mice. The EV surface contains a CD64 protein that has a tissue targeting peptide and a humanized monoclonal antibody. Cells sequentially transfected with plasmid DNAs encoding for the RNA and protein of interest by Transwell®-based asymmetric cell electroporation release abundant targeted EVs with high RNA loading. Together with a low dose chemotherapy drug, Gemcitabine, dtEVs suppress large orthotopic PANC-1 and patient derived xenograft tumours and metastasis in mice and extended animal survival. Our work presents a clinically accessible and scalable way to produce abundant EVs for delivering multiple gene cargoes to large solid tumours.
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Affiliation(s)
- Chi-Ling Chiang
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, 43210, USA
- Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Yifan Ma
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, 43210, USA
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Ya-Chin Hou
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan
- Division of General Surgery, Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Junjie Pan
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Sin-Yu Chen
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Ming-Hsien Chien
- Genomics Research Center, Academia Sinica, Taipei, 11529, Taiwan
| | - Zhi-Xuan Zhang
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Wei-Hsiang Hsu
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Xinyu Wang
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Jingjing Zhang
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Hong Li
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Lili Sun
- Key Laboratory for Ultrafine Materials of Ministry of Education and School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
| | | | - Inyoul Lee
- Institute of Systems Biology, Seattle, WA, 98109, USA
| | - Xing-Yu Chen
- Brain Research Center, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Yeh-Shiu Chu
- Brain Research Center, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Chi Zhang
- College of Pharmacy, The Ohio State University, Columbus, OH, 43210, USA
| | - Tai-Shan Cheng
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Wen Jiang
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Betty Y S Kim
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Eduardo Reategui
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Robert Lee
- College of Pharmacy, The Ohio State University, Columbus, OH, 43210, USA
| | - Yuan Yuan
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, 43210, USA
- Key Laboratory for Ultrafine Materials of Ministry of Education and School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Hsiao-Chun Liu
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan
- Division of General Surgery, Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Kai Wang
- Institute of Systems Biology, Seattle, WA, 98109, USA
| | - Michael Hsiao
- Genomics Research Center, Academia Sinica, Taipei, 11529, Taiwan
| | - Chi-Ying F Huang
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan.
| | - Yan-Shen Shan
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan.
- Division of General Surgery, Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan.
| | - Andrew S Lee
- Institute for Cancer Research, Shenzhen Bay Laboratory, Shenzhen, 518055, China.
- School of Chemical Biology and Biochemistry, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
| | - L James Lee
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, 43210, USA.
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan.
- Spot Biosystems Ltd., Palo Alto, CA, 94305, USA.
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Nizam R, Al-Ozairi E, Goodson JM, Melhem M, Davidsson L, Alkhandari H, Al Madhoun A, Shamsah S, Qaddoumi M, Alghanim G, Alhasawi N, Abu-Farha M, Abubaker J, Shi P, Hartman ML, Tavares M, Bitar M, Ali H, Arefanian H, Devarajan S, Al-Refaei F, Alsmadi O, Tuomilehto J, Al-Mulla F. Caveolin-1 Variant Is Associated With the Metabolic Syndrome in Kuwaiti Children. Front Genet 2018; 9:689. [PMID: 30622557 PMCID: PMC6308323 DOI: 10.3389/fgene.2018.00689] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 12/11/2018] [Indexed: 12/18/2022] Open
Abstract
Caveolin-1 (CAV1) variants have been suggested to be associated with obesity and related metabolic disorders, but information based on human studies is limited. In the present study, we aimed to investigate the potential association between the CAV1 rs1997623 C/A variant and metabolic syndrome (MetS) in Kuwaiti children. DNA from saliva samples collected from 1313 Kuwaiti children (mean age: 12 years) were genotyped using the TaqMan SNP genotyping assay. The classification of MetS was based on the presence/absence of four indicators; (1) central obesity, (2) elevated systolic or diastolic blood pressure, (3) low salivary high-density lipoprotein cholesterol (HDLC), and (4) high salivary glucose. In this study, children with MetS scored ≥3, children in the intermediate metabolic group scored 1 or 2 and children without MetS scored 0. About one-third of the children were obese. A total of 246 children (18.7%) were classified as having MetS; 834 children (63.5%) were in the intermediate metabolic group, and 233 children (17.7%) had no indication of MetS. Obesity was highly prevalent in the MetS group (91.9%) while 26.8% of children were obese in the intermediate metabolic group. None of the children were obese in the group without MetS. Analysis of the CAV1 rs1997623 variant revealed a significant association of the A-allele (p = 0.01, Odds Ratio (OR) = 1.66) and the heterozygous CA-genotype (p = 0.005, OR = 1.88) with MetS. Consistently, the A-allele (p = 0.002, OR = 1.71) and CA-genotype (p = 0.005, OR = 1.70) also showed significant association with the intermediate metabolic group. Furthermore, the A-allele (p = 0.01, OR = 1.33) and the CA-genotype (p = 0.008, OR = 1.55) were associated with low levels of saliva HDLC. Individuals who were heterozygous or homozygous for the variant (CA/AA) showed significantly lower levels of high HDLC compared to those harboring the CC-genotype (p = 0.023). Our study revealed a novel association of the CAV1 rs1997623 variant with the MetS and with low saliva HDLC levels in young Kuwaiti children and indicated the need for further in-depth studies to unravel the role of CAV1 gene in the genetic etiology of MetS.
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Affiliation(s)
- Rasheeba Nizam
- Functional Genomics Unit, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Ebaa Al-Ozairi
- Clinical Division, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Jo Max Goodson
- Applied Oral Sciences, The Forsyth Institute, Cambridge, MA, United States
| | - Motesam Melhem
- Functional Genomics Unit, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Lena Davidsson
- Family Medicine and Pediatric Unit, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Hessa Alkhandari
- Family Medicine and Pediatric Unit, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Ashraf Al Madhoun
- Functional Genomics Unit, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Sara Shamsah
- Faculty of Allied Health Sciences, Kuwait University, Kuwait City, Kuwait
| | - Malak Qaddoumi
- Functional Genomics Unit, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Ghazi Alghanim
- Functional Genomics Unit, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Nouf Alhasawi
- Functional Genomics Unit, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Mohamed Abu-Farha
- Biochemistry and Molecular Biology Unit, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Jehad Abubaker
- Biochemistry and Molecular Biology Unit, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Ping Shi
- Applied Oral Sciences, The Forsyth Institute, Cambridge, MA, United States
| | - Mor-Li Hartman
- Applied Oral Sciences, The Forsyth Institute, Cambridge, MA, United States
| | - Mary Tavares
- Applied Oral Sciences, The Forsyth Institute, Cambridge, MA, United States
| | - Milad Bitar
- Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Hamad Ali
- Faculty of Allied Health Sciences, Kuwait University, Kuwait City, Kuwait
| | | | - Sriraman Devarajan
- National Dasman Diabetes Biobank, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Faisal Al-Refaei
- Clinical Division, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Osama Alsmadi
- Cell Therapy and Applied Genomics, King Hussein Cancer Center, Amman, Jordan
| | | | - Fahd Al-Mulla
- Functional Genomics Unit, Dasman Diabetes Institute, Kuwait City, Kuwait
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3
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Zhang X, Sessa WC, Fernández-Hernando C. Endothelial Transcytosis of Lipoproteins in Atherosclerosis. Front Cardiovasc Med 2018; 5:130. [PMID: 30320124 PMCID: PMC6167422 DOI: 10.3389/fcvm.2018.00130] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 09/03/2018] [Indexed: 12/12/2022] Open
Abstract
Seminal studies from Nikolai Anichckov identified the accumulation of cholesterol in the arteries as the initial event that lead to the formation of atherosclerotic plaques. Further studies by Gofman and colleagues demonstrated that high levels of circulating low-density lipoprotein cholesterol (LDL-C) was responsible for the accelerated atherosclerosis observed in humans. These findings were confirmed by numerous epidemiological studies which identified elevated LDL-C levels as a major risk factor for cardiovascular disease. LDL infiltrates in the arterial wall and interacts with the proteoglycan matrix promoting the retention and modification of LDL to a toxic form, which results in endothelial cell (EC) activation and vascular inflammation. Despite the relevance of LDL transport across the endothelium during atherogenesis, the molecular mechanism that control this process is still not fully understood. A number of studies have recently demonstrated that low density lipoprotein (LDL) transcytosis across the endothelium is dependent on the function of caveolae, scavenger receptor B1 (SR-B1), activin receptor-like kinase 1 (ALK1), and LDL receptor (LDLR), whereas high-density lipoproteins (HDL) and its major protein component apolipoprotein AI transcytose ECs through SR-B1, ATP-Binding cassette transporter A1 (ABCA1) and ABCG1. In this review article, we briefly summarize the function of the EC barrier in regulating lipoprotein transport, and its relevance during the progression of atherosclerosis. A better understanding of the mechanisms that mediate lipoprotein transcytosis across ECs will help to develop therapies targeting the early events of atherosclerosis and thus exert potential benefits for treating atherosclerotic vascular disease.
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Affiliation(s)
- Xinbo Zhang
- Vascular Biology and Therapeutics Program, Integrative Cell Signaling and Neurobiology of Metabolism Program, Department of Comparative Medicine and Department of Pathology, Yale University School of Medicine, New Haven, CT, United States
| | - William C Sessa
- Vascular Biology and Therapeutics Program, Department of Pharmacology, Yale University School of Medicine, New Haven, CT, United States
| | - Carlos Fernández-Hernando
- Vascular Biology and Therapeutics Program, Integrative Cell Signaling and Neurobiology of Metabolism Program, Department of Comparative Medicine and Department of Pathology, Yale University School of Medicine, New Haven, CT, United States
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4
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Mo ZC, Ren K, Liu X, Tang ZL, Yi GH. A high-density lipoprotein-mediated drug delivery system. Adv Drug Deliv Rev 2016; 106:132-147. [PMID: 27208399 DOI: 10.1016/j.addr.2016.04.030] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 04/13/2016] [Accepted: 04/27/2016] [Indexed: 01/08/2023]
Abstract
High-density lipoprotein (HDL) is a comparatively dense and small lipoprotein that can carry lipids as a multifunctional aggregate in plasma. Several studies have shown that increasing the levels or improving the functionality of HDL is a promising target for treating a wide variety of diseases. Among lipoproteins, HDL particles possess unique physicochemical properties, including naturally synthesized physiological components, amphipathic apolipoproteins, lipid-loading and hydrophobic agent-incorporating characteristics, specific protein-protein interactions, heterogeneity, nanoparticles, and smaller size. Recently, the feasibility and superiority of using HDL particles as drug delivery vehicles have been of great interest. In this review, we summarize the structure, constituents, biogenesis, remodeling, and reconstitution of HDL drug delivery systems, focusing on their delivery capability, characteristics, applications, manufacturing, and drug-loading and drug-targeting characteristics. Finally, the future prospects are presented regarding the clinical application and challenges of using HDL as a pharmacodelivery carrier.
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Affiliation(s)
- Zhong-Cheng Mo
- Institute of Cardiovascular Disease, Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang City 421001, Hunan Province, China; Department of Histology and Embryology, University of South China, Hengyang, Hunan 421001, China
| | - Kun Ren
- Institute of Cardiovascular Disease, Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang City 421001, Hunan Province, China
| | - Xing Liu
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, 100005 Beijing, China
| | - Zhen-Li Tang
- Institute of Cardiovascular Disease, Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang City 421001, Hunan Province, China
| | - Guang-Hui Yi
- Institute of Cardiovascular Disease, Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang City 421001, Hunan Province, China.
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5
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Caveolin-1 Function in Liver Physiology and Disease. Trends Mol Med 2016; 22:889-904. [DOI: 10.1016/j.molmed.2016.08.007] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/14/2016] [Accepted: 08/17/2016] [Indexed: 12/18/2022]
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6
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Zurkinden L, Mansour YT, Rohrbach B, Vogt B, Mistry HD, Escher G. Hepatic caveolin-1 is enhanced in Cyp27a1/ApoE double knockout mice. FEBS Open Bio 2016; 6:1025-1035. [PMID: 28149711 PMCID: PMC5275772 DOI: 10.1002/2211-5463.12123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/26/2016] [Accepted: 08/29/2016] [Indexed: 01/31/2023] Open
Abstract
Sterol 27‐hydroxylase (CYP27A1) is involved in bile acid synthesis and cholesterol homoeostasis. Cyp27a1(−/−)/Apolipoprotein E(−/−) double knockout mice (DKO) fed a western diet failed to develop atherosclerosis. Caveolin‐1 (CAV‐1), the main component of caveolae, is associated with lipid homoeostasis and has regulatory roles in vascular diseases. We hypothesized that liver CAV‐1 would contribute to the athero‐protective mechanism in DKO mice. Cyp27a1(+/+)/ApoE(−/−) (ApoE KO), Cyp27a1(+/−)/ApoE(−/−) (het), and DKO mice were fed a western diet for 2 months. Atherosclerotic plaque and CAV‐1 protein were quantified in aortas. Hepatic Cav‐1 mRNA was assessed using qPCR, CAV‐1 protein by immunohistochemistry and western blotting. Total hepatic and plasma cholesterol was measured using chemiluminescence. Cholesterol efflux was performed in RAW264.7 cells, using mice plasma as acceptor. CAV‐1 protein expression in aortas was increased in endothelial cells of DKO mice and negatively correlated with plaque surface (P < 0.05). In the liver, both CAV‐1 protein and mRNA expression doubled in DKO, compared to ApoE KO and het mice (P < 0.001 for both) and was negatively correlated with total hepatic cholesterol (P < 0.05). Plasma from DKO, ApoE KO and het mice had the same efflux capacity. In the absence of CYP27A1, CAV‐1 overexpression might have an additional athero‐protective role by partly overcoming the defect in CYP27A1‐mediated cholesterol efflux.
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Affiliation(s)
- Line Zurkinden
- Department of Nephrology, Hypertension, Clinical Pharmacology and Clinical Research University of Bern Switzerland
| | - Yosef T Mansour
- Division of Women's Health King's College London Women's Health Academic Centre UK
| | - Beatrice Rohrbach
- Department of Nephrology, Hypertension, Clinical Pharmacology and Clinical Research University of Bern Switzerland
| | - Bruno Vogt
- Department of Nephrology, Hypertension, Clinical Pharmacology and Clinical Research University of Bern Switzerland
| | - Hiten D Mistry
- Department of Nephrology, Hypertension, Clinical Pharmacology and Clinical Research University of Bern Switzerland; Division of Child Health, Obstetrics & Gynaecology School of Medicine University of Nottingham UK
| | - Geneviève Escher
- Department of Nephrology, Hypertension, Clinical Pharmacology and Clinical Research University of Bern Switzerland
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Caveolin-1 facilitates internalization and degradation of ABCA1 and probucol oxidative products interfere with this reaction to increase HDL biogenesis. Atherosclerosis 2016; 253:54-60. [PMID: 27579791 DOI: 10.1016/j.atherosclerosis.2016.08.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 08/01/2016] [Accepted: 08/23/2016] [Indexed: 11/21/2022]
Abstract
BACKGROUND AND AIMS Expression of ATP binding cassette transporter (ABC) A1, a key membrane protein for biogenesis of high-density lipoprotein (HDL), is regulated not only by its gene transcription but also by its intracellular degradation to modulate plasma HDL concentration. We previously showed that inhibition of ABCA1 degradation by probucol oxidative products, spiroquinone (SQ) and diphenoquinone (DQ), increased HDL biogenesis and reverse cholesterol transport, and achieved reduction of atherosclerosis in animal models. The background mechanism has thus been investigated. METHODS Involvement of caveolin-1, a protein of multiple functions in cell biology, particularly in cholesterol trafficking, has been examined for its roles in ABCA1 degradation as well as the effects of SQ and DQ on the reaction. RESULTS ABCA1 protein was increased in caveolin-1-deficient mouse embryonic fibroblasts, not by increase of transcription but by decrease in its internalization and degradation. Transfection and expression of caveolin-1 normalized the protein level and the rate of degradation of ABCA1. Immunoprecipitation experiments demonstrated association between ABCA1 and caveolin-1 and SQ and DQ disrupted this interaction. The effects of SQ and DQ to increase ABCA1 and cell cholesterol release induced by apolipoprotein A-I were dependent on expression of caveolin-1. Fluorescence imaging of ABCA1 and caveolin-1 in cultured cells demonstrated their co-localization as well as its disruption by SQ and DQ, being consistent with the biochemical findings. CONCLUSIONS Caveolin-1 enhances internalization and degradation of ABCA1 by its association with ABCA1. Interference of this interaction by probucol oxidative products suppresses ABCA1 degradation and increase HDL biogenesis.
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Chen YH, Lin WW, Liu CS, Hsu LS, Lin YM, Su SL. Caveolin-1 provides palliation for adverse hepatic reactions in hypercholesterolemic rabbits. PLoS One 2014; 9:e71862. [PMID: 24475013 PMCID: PMC3901645 DOI: 10.1371/journal.pone.0071862] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Accepted: 09/21/2013] [Indexed: 12/17/2022] Open
Abstract
Caveolins are an essential component of cholesterol-rich invaginations of the plasma membrane known as caveolae. These flask-shaped, invaginated structures participate in a number of important cellular processes, including vesicular transport, cholesterol homeostasis, and signal transduction. We investigated the effects of CAV-1 on mitochondrial biogenesis and antioxidant enzymes in hypercholesterolemia-affected target organs. A total of eighteen male New Zealand white rabbits were divided into three groups: a normal-diet group, an untreated hypercholesterolemia-induced group, and a hypercholesterolemia-induced group that received intravenous administration of antennapedia-CAV-1 (AP-CAV-1) peptide every 2 days for 2 weeks. Serum biochemistry, CAV-1 distribution, neutral lipid distribution, mitochondrial morphology, biogenesis-mediated protein content, oxidative stress balance, antioxidant enzyme levels, and apoptotic cell death of liver tissue were analysed. Hepatic and circulating cholesterol and low-density lipoprotein cholesterol (LDL-C) levels differed significantly between the three groups (P<0.05). Immunohistochemical staining intensity of CAV-1 was greater in AP-CAV-1-treated rabbits than in untreated rabbits, especially in the vicinity of the liver vasculature. The high levels of neutral lipids, malondialdehyde, peroxisome proliferator-activated receptor-γ coactive 1α (PGC-1α), and nuclear respiratory factor-1 (NRF-1) seen in untreated hypercholesteremic animals were attenuated by administration of AP-CAV-1 (P<0.05). In addition, mitochondria in animals that received treatment exhibited darker electron-dense matrix and integrated cristae. Furthermore, the levels of ROS modulator 1 (Romo1) and superoxide dismutase (SOD)-2, as well as catalase activity were significantly lower in CAV-1-treated hypercholesterolemic rabbits (P<0.05). AP-CAV-1 treatment also restored mitochondrial respiratory chain subunit protein content (OXPHOS complexes I–V), thereby preserving mitochondrial function (P<0.05). Furthermore, AP-CAV-1 treatment significantly suppressed apoptotic cell death, as evidenced by a reduction in the number of TUNEL-positive cells. Our results indirectly indicate that CAV-1 mediates the negative effects of PGC-1α on hepatic mitochondrial respiratory chain function, promotes the antioxidant enzyme defence system, and maintains mitochondrial biogenesis.
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Affiliation(s)
- Ya-Hui Chen
- Vascular and Genomic Center, Changhua Christian Hospital, Changhua, Taiwan
- Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung, Taiwan
| | - Wei-Wen Lin
- Division of Cardiovascular Center, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Chin-San Liu
- Vascular and Genomic Center, Changhua Christian Hospital, Changhua, Taiwan
- Graduate Institute of Integrative Medicine, China Medical University, Taichung, Taiwan
| | - Li-Sung Hsu
- Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung, Taiwan
| | - Yueh-Min Lin
- Department of Pathology, Changhua Christian Hospital, Changhua, Taiwan
- Department of Medical Technology, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli, Taiwan
| | - Shih-Li Su
- Vascular and Genomic Center, Changhua Christian Hospital, Changhua, Taiwan
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan
- * E-mail:
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9
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Caveolin-1 Is Necessary for Hepatic Oxidative Lipid Metabolism: Evidence for Crosstalk between Caveolin-1 and Bile Acid Signaling. Cell Rep 2013; 4:238-47. [DOI: 10.1016/j.celrep.2013.06.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Revised: 03/04/2013] [Accepted: 06/14/2013] [Indexed: 12/14/2022] Open
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10
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Qi R, Mullen DG, Baker JR, Holl MMB. The mechanism of polyplex internalization into cells: testing the GM1/caveolin-1 lipid raft mediated endocytosis pathway. Mol Pharm 2010; 7:267-79. [PMID: 20025295 PMCID: PMC2826151 DOI: 10.1021/mp900241t] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The GM1/caveolin-1 lipid raft mediated endocytosis mechanism was explored for generation 5 and 7 poly(amidoamine) dendrimer polyplexes employing the Cos-7, 293A, C6, HeLa, KB, and HepG2 cell lines. Expression levels of GM1 and caveolin-1 were measured using dot blot and Western blot, respectively. The level of GM1 in the cell plasma membrane was adjusted by incubation with exogenous GM1 or ganglioside inhibitor PPMP, and the level of CAV-1 was adjusted by upregulation with the adenovirus vector expressed caveolin-1 (AdCav-1). Cholera toxin B subunit was employed as a positive control for uptake in all cases. No evidence was found for a GM1/caveolin-1 lipid raft mediated endocytosis mechanism for the generation 5 and 7 poly(amidoamine) dendrimer polyplexes.
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Affiliation(s)
- Rong Qi
- Peking University Institute of Cardiovascular Sciences, Peking University Health Science Center, Peking University, Beijing 100083, China
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11
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Frank PG, Pavlides S, Cheung MWC, Daumer K, Lisanti MP. Role of caveolin-1 in the regulation of lipoprotein metabolism. Am J Physiol Cell Physiol 2008; 295:C242-8. [PMID: 18508910 DOI: 10.1152/ajpcell.00185.2008] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Lipoprotein metabolism plays an important role in the development of several human diseases, including coronary artery disease and the metabolic syndrome. A good comprehension of the factors that regulate the metabolism of the various lipoproteins is therefore key to better understanding the variables associated with the development of these diseases. Among the players identified are regulators such as caveolins and caveolae. Caveolae are small plasma membrane invaginations that are observed in terminally differentiated cells. Their most important protein marker, caveolin-1, has been shown to play a key role in the regulation of several cellular signaling pathways and in the regulation of plasma lipoprotein metabolism. In the present paper, we have examined the role of caveolin-1 in lipoprotein metabolism using caveolin-1-deficient (Cav-1(-/-)) mice. Our data show that, while Cav-1(-/-) mice show increased plasma triglyceride levels, they also display reduced hepatic very low-density lipoprotein (VLDL) secretion. Additionally, we also found that a caveolin-1 deficiency is associated with an increase in high-density lipoprotein (HDL), and these HDL particles are enriched in cholesteryl ester in Cav-1(-/-) mice when compared with HDL obtained from wild-type mice. Finally, our data suggest that a caveolin-1 deficiency prevents the transcytosis of LDL across endothelial cells, and therefore, that caveolin-1 may be implicated in the regulation of plasma LDL levels. Taken together, our studies suggest that caveolin-1 plays an important role in the regulation of lipoprotein metabolism by controlling their plasma levels as well as their lipid composition. Thus caveolin-1 may also play an important role in the development of atherosclerosis.
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Affiliation(s)
- Philippe G Frank
- Kimmel Cancer Center, Department of Cancer Biology, and Biochemistry and Molecular Biology, and Stem Cell Biology and Regenerative Medicine Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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12
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Richter T, Floetenmeyer M, Ferguson C, Galea J, Goh J, Lindsay MR, Morgan GP, Marsh BJ, Parton RG. High-resolution 3D quantitative analysis of caveolar ultrastructure and caveola-cytoskeleton interactions. Traffic 2008; 9:893-909. [PMID: 18397183 DOI: 10.1111/j.1600-0854.2008.00733.x] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Caveolae are characteristic invaginations of the mammalian plasma membrane (PM) implicated in lipid regulation, signal transduction and endocytosis. We have employed electron microscope tomography (ET) to quantify caveolae structure-function relationships in three-dimension (3D) at high resolution both in conventionally fixed and in fast-frozen/freeze-substituted (intact) cells as well as immunolabelled PM lawns. Our findings provide a detailed quantitative comparison of the average caveola dimensions for different cell types including tissue endothelial cells and cultured 3T3-L1 adipocytes. These studies revealed the presence of a spiked caveolar coat and a wide caveolar neck open to the extracellular milieu that is sensitive to conventional fixation; the neck region appeared to form a specialized microdomain with associated cytoplasmic material. In endothelial cells in situ in pancreatic islets of Langerhans, the diaphragm spanning the caveolar opening was clearly resolved by ET, and the involuted 3D topology of the cell surface mapped to measure the contribution of caveolar membranes to local increases in the surface area of the PM. The complexity of connections among caveolae and to the actin cytoskeleton and microtubules suggests that individual caveolae may be interconnected through a complex filamentous network to form a single functional unit.
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Affiliation(s)
- Tobias Richter
- Institute for Molecular Bioscience, Queensland Bioscience Precinct, The University of Queensland, Brisbane, Queensland 4072, Australia
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13
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Truong TQ, Aubin D, Bourgeois P, Falstrault L, Brissette L. Opposite effect of caveolin-1 in the metabolism of high-density and low-density lipoproteins. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:24-36. [PMID: 16443388 DOI: 10.1016/j.bbalip.2005.12.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2005] [Revised: 12/06/2005] [Accepted: 12/12/2005] [Indexed: 11/21/2022]
Abstract
Receptors of the scavenger class B family were reported to be localized in caveolae, the cell surface microdomains rich in free cholesterol and glycosphyngolipids, which are characterized by the presence of caveolin-1. Parenchymal hepatic and hepatoma HepG2 cells express very low levels of caveolin-1. In the present study, stable transformants of HepG2 cells expressing caveolin-1 were generated to address the effect of caveolin-1 on receptor activity. Compared to normal cells, these cells show higher (125)I-bovine serum albumin (BSA) uptake and cholesterol efflux, two indicators of functional caveolae. By immunoprecipitation, cell fractionation and confocal analyses, we found that caveolin-1 is well colocalized with the cluster of differentiation-36 (CD36) and the low-density lipoprotein (LDL) receptor (LDLr) but to a lesser extent with the scavenger receptor class B type I (SR-BI) in HepG2 cells expressing caveolin-1. However, caveolin-1 expression favors the dimerization of SR-BI. Two clones of cells expressing caveolin-1 were investigated for their lipoprotein metabolism activity. Compared to normal cells, these cells show a 71-144% increase in (125)I-LDL degradation. The analysis of the cholesteryl esters (CE)-selective uptake (CE association minus protein association) revealed that the expression of caveolin-1 in HepG2 cells decreases by 59%-73% LDL-CE selective uptake and increases high-density lipoprotein (HDL)-CE selective uptake by 44%-66%. We conclude that the expression of caveolin-1 in HepG2 cells moves the balance of LDL degradation/CE selective uptake towards degradation and favors HDL-CE selective uptake. Thus, in the normal hepatic parenchymal situation where caveolin-1 is poorly expressed, LDL-CE selective uptake is the preferred pathway.
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Affiliation(s)
- To Quyen Truong
- Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-ville, Montréal, Québec, Canada H3C 3P8.
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14
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Frank PG, Lisanti MP. Caveolin-1 and caveolae in atherosclerosis: differential roles in fatty streak formation and neointimal hyperplasia. Curr Opin Lipidol 2004; 15:523-9. [PMID: 15361787 DOI: 10.1097/00041433-200410000-00005] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE OF REVIEW Caveolae are 50-100 nm cell surface plasma membrane invaginations observed in terminally differentiated cells. They are characterized by the presence of the protein marker caveolin-1. Caveolae and caveolin-1 are present in almost every cell type that has been implicated in the development of an atheroma. These include endothelial cells, macrophages, and smooth muscle cells. Caveolae and caveolin-1 are involved in regulating several signal transduction pathways and processes that play an important role in atherosclerosis. RECENT FINDINGS Several recent studies using genetically engineered mice (Cav-1 (-/-) null animals) have now clearly demonstrated a role for caveolin-1 and caveolae in the development of atherosclerosis. In fact, they suggest a rather complex one, either proatherogenic or antiatherogenic, depending on the cell type examined. For example, in endothelial cells, caveolin-1 and caveolae may play a proatherogenic role by promoting the transcytosis of LDL-cholesterol particles from the blood to the sub-endothelial space. In contrast, in smooth muscle cells, the ability of caveolin-1 to negatively regulate cell proliferation (neointimal hyperplasia) may have an antiatherogenic effect. SUMMARY Caveolin-1 and caveolae play an important role in several steps involved in the initiation of an atheroma. Development of new drugs that regulate caveolin-1 expression may be important in the prevention or treatment of atherosclerotic vascular disease.
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Affiliation(s)
- Philippe G Frank
- Department of Molecular Pharmacology and the Albert Einstein Diabetes Research and Training Center (DRTC), and Department of Urology, Albert Einstein College of Medicine, The Bronx, New York 10461, USA.
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15
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Rhainds D, Brissette L. The role of scavenger receptor class B type I (SR-BI) in lipid trafficking. defining the rules for lipid traders. Int J Biochem Cell Biol 2004; 36:39-77. [PMID: 14592533 DOI: 10.1016/s1357-2725(03)00173-0] [Citation(s) in RCA: 158] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The scavenger receptor class B type I (SR-BI) is a 509-amino acid, 82 kDa glycoprotein, with two cytoplasmic C- and N-terminal domains separated by a large extracellular domain. The aim of this review is to define the role of SR-BI as a lipoprotein receptor responsible for selective uptake of cholesteryl esters (CE) from high density lipoprotein (HDL) and low density lipoprotein (LDL) and free cholesterol (FC) efflux to lipoprotein acceptors. These activities depend on lipoprotein binding to its extracellular domain and subsequent lipid exchange at the plasma membrane. CE selective uptake supplies cholesterol to liver and steroidogenic tissues, for biliary cholesterol secretion and steroid hormone synthesis. Genetically modified mice have confirmed SR-BI's major role in tissue cholesterol uptake and in reverse cholesterol transport, i.e. cholesterol turnover. Accordingly, cellular cholesterol level, estrogens and trophic hormones regulate SR-BI expression by both transcriptional and post-transcriptional mechanisms. Importantly, mouse SR-BI overexpression has both corrective and preventive effects on atherosclerosis. Human SR-BI has very similar tissue distribution, binding properties and lipid transfer activities compared to rodent SR-BI. However, human plasma has most of its cholesterol in LDL. Thus, there is considerable interest to develop anti-atherogenic strategies involving human SR-BI-mediated increases in reverse cholesterol transport through HDL and/or LDL.
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MESH Headings
- Amino Acid Sequence
- Animals
- Biological Transport, Active
- CD36 Antigens
- Cell Membrane/chemistry
- Cell Membrane/genetics
- Cell Membrane/metabolism
- Cell Membrane/physiology
- Humans
- Lipid Metabolism
- Lipoproteins/metabolism
- Models, Biological
- Promoter Regions, Genetic
- Protein Structure, Tertiary
- Receptors, Immunologic/chemistry
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Receptors, Immunologic/physiology
- Receptors, Scavenger
- Scavenger Receptors, Class B
- Tissue Distribution
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Affiliation(s)
- David Rhainds
- Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succ. Centre-Ville, Montreal, Que., Canada H3C 3P8.
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16
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Connelly MA, Williams DL. Scavenger receptor BI: a scavenger receptor with a mission to transport high density lipoprotein lipids. Curr Opin Lipidol 2004; 15:287-95. [PMID: 15166784 DOI: 10.1097/00041433-200406000-00008] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW This review will survey recent findings on the cholesterol transport and scavenger functions of scavenger receptor BI. Although scavenger receptor BI and CD36 bind many of the same ligands, these two receptors have very specific lipid transport functions: CD36 facilitates the uptake of long chain fatty acids and SR-BI mediates the transport of cholesterol and cholesteryl ester from HDL particles. Scavenger receptor BI is a physiologically relevant HDL receptor that, along with HDL, is protective against cardiovascular disease. Its atheroprotective role has been hypothesized to be due to its function in the reverse cholesterol transport pathway. RECENT FINDINGS Recent studies suggest that scavenger receptor BI function is not only crucial for cholesterol delivery to the liver but is also important for cholesterol efflux at the vessel wall. Therefore, the receptor acts at both ends of the reverse cholesterol transport pathway. In addition, it stimulates nitric oxide production in endothelial cells, which may also contribute to its positive influence on the vasculature. Lastly, the glycoprotein was cloned as a scavenger receptor and in some cases is still thought to operate in this fashion. SUMMARY It will be interesting to follow future research on scavenger receptor BI that will delineate its functions in cholesterol transport as well as its scavenger functions. Additionally, we are only beginning to learn of the glycoprotein's effects on disease states besides atherosclerosis and cardiovascular disease.
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Affiliation(s)
- Margery A Connelly
- Department of Pharmacological Sciences, University Medical Center, State University of New York at Stony Brook, Stony Brook, NY 11794-8651, USA
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17
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Fu Y, Hoang A, Escher G, Parton RG, Krozowski Z, Sviridov D. Expression of Caveolin-1 Enhances Cholesterol Efflux in Hepatic Cells. J Biol Chem 2004; 279:14140-6. [PMID: 14729661 DOI: 10.1074/jbc.m311061200] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
HepG2 cells were stably transfected with human caveolin-1 (HepG2/cav cells). Transfection resulted in expression of caveolin-1 mRNA, a high abundance of caveolin-1 protein, and the formation of caveolae on the plasma membrane. Cholesterol efflux from HepG2/cav cells was 280 and 45% higher than that from parent HepG2 cells when human plasma and human apoA-I, respectively, were used as acceptors. The difference in efflux was eliminated by treatment of cells with progesterone. There was no difference in cholesterol efflux to cyclodextrin. Cholesterol efflux from plasma membrane vesicles was similar for the two cell types. Transfection led to a 40% increase in the amount of plasma membrane cholesterol in cholesterol-rich domains (caveolae and/or rafts) and a 67% increase in the rate of cholesterol trafficking from intracellular compartments to these domains. Cholesterol biosynthesis in HepG2/cav cells was increased by 2-fold, and cholesterol esterification was reduced by 50% compared with parent HepG2 cells. The proliferation rate of transfected cells was significantly lower than that of non-transfected cells. Transfection did not affect expression of ABCA1 or the abundance of ABCA1 protein, but decreased secretion of apoA-I. We conclude that overexpression of caveolin-1 in hepatic cells stimulates cholesterol efflux by enhancing transfer of cholesterol to cholesterol-rich domains in the plasma membrane.
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Affiliation(s)
- Ying Fu
- Wynn Domain, Baker Heart Research Institute, Melbourne, Victoria 8008, Australia
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18
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Abstract
Caveolins are markers of caveolae, invaginations in the plasma membrane, and there are three members of the family in vertebrates. Caveolins participate in many important cellular processes, including vesicular transport, cholesterol homeostasis, signal transduction, and tumor suppression. The caveolin gene family has three members in vertebrates: caveolin-1, caveolin-2, and caveolin-3. So far, most caveolin-related research has been conducted in mammals, but the proteins have also been found in other animals, including Xenopus laevis, Fugu rubripes, and Caenorhabditis elegans. Caveolins can serve as protein markers of caveolae ('little caves'), invaginations in the plasma membrane 50-100 nanometers in diameter. Caveolins are found predominantly at the plasma membrane but also in the Golgi, the endoplasmic reticulum, in vesicles, and at cytosolic locations. They are expressed ubiquitously in mammals, but their expression levels vary considerably between tissues. The highest levels of caveolin-1 (also called caveolin, Cav-1 and VIP2I) are found in terminally-differentiated cell types, such as adipocytes, endothelia, smooth muscle cells, and type I pneumocytes. Caveolin-2 (Cav-2) is colocalized and coexpressed with Cav-1 and requires Cav-1 for proper membrane targeting; the Cav-2 gene also maps to the same chromosomal region as Cav-1 (7q31.1 in humans). Caveolin-3 (Cav-3) has greater protein-sequence similarity to Cav-1 than to Cav-2, but it is expressed mainly in muscle cells, including smooth, skeletal, and cardiac myocytes. Caveolins participate in many important cellular processes, including vesicular transport, cholesterol homeostasis, signal transduction, and tumor suppression.
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Affiliation(s)
- Terence M Williams
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
- The Albert Einstein Cancer Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Michael P Lisanti
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
- The Albert Einstein Cancer Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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Moreno M, Molina H, Amigo L, Zanlungo S, Arrese M, Rigotti A, Miquel JF. Hepatic overexpression of caveolins increases bile salt secretion in mice. Hepatology 2003; 38:1477-88. [PMID: 14647059 DOI: 10.1016/j.hep.2003.09.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Caveolins are cholesterol-binding proteins involved in the regulation of several intracellular processes, including cholesterol transport. Because hepatocytes express caveolin-1 and caveolin-2, these proteins might modulate hepatic lipid metabolism and biliary lipid secretion. Our aim was to investigate the potential physiologic role of caveolins in hepatic cholesterol and bile salt (BS) metabolism and transport using adenoviral gene transfer. C57BL/6 mice were infected with recombinant human caveolin-1 and caveolin-2 adenoviruses. Mice infected with adenovirus lacking the transgene were used as controls. Hepatic caveolin expression was evaluated by immunochemical methods. Reverse-transcription polymerase chain reaction (RT-PCR) and immunoblotting were used to assess messenger RNA (mRNA) levels and protein mass of BS transporters (sodium taurocholate cotransporting polypeptide [Ntcp] and bile salt export pump [Bsep]). Serum, liver, biliary, and fecal biochemical determinations and BS maximal secretory rate (SRm) were performed by standard methods. Ad.Cav-1- and Ad.Cav-2-infected mice exhibited a 10- and 7-fold increase in hepatic caveolin-1 and caveolin-2 protein expression, respectively. Caveolin-1-overexpressing mice had a significant increase in plasma high-density lipoprotein (HDL) cholesterol and hepatic free cholesterol content, whereas total plasma cholesterol and triglyceride levels remained unchanged. Hepatic caveolin-1 and/or caveolin-2 overexpression significantly increased bile flow and secretion of all biliary lipids. Caveolin-1-overexpressing mice showed a 2.5-fold increase in taurocholate (TC) SRm, indicating increased canalicular BS transport capacity. BS pool size and fecal BS excretion remained within the normal range in mice with Cav-1 overexpression. No changes were seen in the protein mass of BS transporters Ntcp and Bsep. In conclusion, our findings indicate that caveolins may play an important role in regulating hepatic BS and cholesterol metabolism.
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Affiliation(s)
- Mauricio Moreno
- Departamento de Gastroenterología, Pontificia Universidad Católica de Chile, Santiago, Chile
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20
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Trigatti BL, Krieger M, Rigotti A. Influence of the HDL receptor SR-BI on lipoprotein metabolism and atherosclerosis. Arterioscler Thromb Vasc Biol 2003; 23:1732-8. [PMID: 12920050 DOI: 10.1161/01.atv.0000091363.28501.84] [Citation(s) in RCA: 194] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The scavenger receptor class B type I (SR-BI) was the first molecularly well-defined cell-surface HDL receptor to be described. SR-BI mediates selective HDL cholesterol uptake by formation of a productive lipoprotein/receptor complex, which requires specific structural domains and conformation states of apolipoprotein A-I present in HDL particles. SR-BI is abundantly expressed in several tissues, including the liver, where its expression is regulated by various mechanisms, including the transcriptional activity of nuclear receptors. The importance of SR-BI in overall HDL cholesterol metabolism and its antiatherogenic activity in vivo has been definitively established by SR-BI gene manipulation in mice. Remarkably, SR-BI/apolipoprotein E double-knockout mice develop complex coronary artery disease, myocardial infarction, and heart failure. Additional studies should help to define the importance of SR-BI in human health and disease.
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21
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Wang L, Connelly MA, Ostermeyer AG, Chen HH, Williams DL, Brown DA. Caveolin-1 does not affect SR-BI-mediated cholesterol efflux or selective uptake of cholesteryl ester in two cell lines. J Lipid Res 2003; 44:807-15. [PMID: 12562842 DOI: 10.1194/jlr.m200449-jlr200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Free cholesterol (FC) has been reported to efflux from cells through caveolae, which are 50-100 nm plasma membrane pits. The 22 kDa protein caveolin-1 is concentrated in caveolae and is required for their formation. The HDL scavenger receptor BI (SR-BI), which stimulates both FC efflux and selective uptake of HDL-derived cholesteryl ester (CE), has been reported to be concentrated in caveolae, suggesting that this localization facilitates flux of FC and CE across the membrane. However, we found that overexpression of caveolin-1 in Fischer rat thyroid (FRT) cells, which lack caveolin-1 and caveolae, or HEK 293 cells, which normally express very low levels of caveolin-1, did not affect FC efflux to HDL or liposomes. Transient expression of SR-B1 did not affect this result. Similarly, caveolin-1 expression did not affect selective uptake of CE from labeled HDL particles in FRT or HEK 293 cells transfected with SR-BI. We conclude that basal and SR-BI-stimulated FC efflux to HDL and liposomes and SR-BI-mediated selective uptake of HDL CE are not affected by caveolin-1 expression in HEK 293 or FRT cells.
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Affiliation(s)
- Libo Wang
- Department of Biochemistry and Cell Biology, SUNY at Stony Brook, NY 11794, USA
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22
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McIntosh AL, Gallegos AM, Atshaves BP, Storey SM, Kannoju D, Schroeder F. Fluorescence and multiphoton imaging resolve unique structural forms of sterol in membranes of living cells. J Biol Chem 2003; 278:6384-403. [PMID: 12456684 DOI: 10.1074/jbc.m205472200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Although cholesterol is an essential component of mammalian membranes, resolution of cholesterol organization in membranes and organelles (i.e. lysosomes) of living cells is hampered by the paucity of nondestructive, nonperturbing methods providing real time structural information. Advantage was taken of the fact that the emission maxima of a naturally occurring fluorescent sterol (dehydroergosterol) were resolvable into two structural forms, monomeric (356 and 375 nm) and crystalline (403 and 426 nm). Model membranes (sterol:phospholipid ratios in the physiological range, e.g. 0.5-1.0), subcellular membrane fractions (plasma membranes, lysosomal membranes, microsomes, and mitochondrial membranes), and lipid rafts/caveolae (plasma membrane cholesterol-rich microdomain purified by a nondetergent method) contained primarily monomeric sterol and only small quantities (i.e. 1-5%) of the crystalline form. In contrast, the majority of sterol in isolated lysosomes was crystalline. However, addition of sterol carrier protein-2 in vitro significantly reduced the proportion of crystalline dehydroergosterol in the isolated lysosomes. Multiphoton laser scanning microscopy (MPLSM) of living L-cell fibroblasts cultured with dehydroergosterol for the first time provided real time images showing the presence of monomeric sterol in plasma membranes, as well as other intracellular membrane structures of living cells. Furthermore, MPLSM confirmed that crystalline sterol colocalized in highest amounts with LysoTracker Green, a lysosomal marker dye. Although crystalline sterol was also detected in the cytoplasm, the extralysosomal crystalline sterol did not colocalize with BODIPY FL C(5)-ceramide, a Golgi marker, and crystals were not associated with the cell surface membrane. These noninvasive, nonperturbing methods demonstrated for the first time that multiple structural forms of sterol normally occurred within membranes, membrane microdomains (lipid rafts/caveolae), and intracellular organelles of living cells, both in vitro and visualized in real time by MPLSM.
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Affiliation(s)
- Avery L McIntosh
- Department of Physiology and Pharmacology, Texas A & M University, Texas Veterinary Medical Center, College Station, Texas 77843-4466, USA
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23
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Kosters A, Jirsa M, Groen AK. Genetic background of cholesterol gallstone disease. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1637:1-19. [PMID: 12527402 DOI: 10.1016/s0925-4439(02)00173-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cholesterol gallstone formation is a multifactorial process involving a multitude of metabolic pathways. The primary pathogenic factor is hypersecretion of free cholesterol into bile. For people living in the Western Hemisphere, this is almost a normal condition, certainly in the elderly, which explains the very high incidence of gallstone disease. It is probably because the multifactorial background genes responsible for the high incidence have not yet been identified, despite the fact that genetic factors clearly play a role. Analysis of the many pathways involved in biliary cholesterol secretion reveals many potential candidates and considering the progress in unraveling the regulatory mechanisms of the responsible genes, identification of the primary gallstone genes will be successful in the near future.
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Affiliation(s)
- Astrid Kosters
- Department of Experimental Hepatology, AMC Liver Center S1-172, Academic Medical Center, Meibergdreef 69-71, 1105 BK, Amsterdam, The Netherlands.
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Azhar S, Reaven E. Scavenger receptor class BI and selective cholesteryl ester uptake: partners in the regulation of steroidogenesis. Mol Cell Endocrinol 2002; 195:1-26. [PMID: 12354669 DOI: 10.1016/s0303-7207(02)00222-8] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The steroidogenic tissues have a special requirement for cholesterol, which is used as a substrate for steroid hormone biosynthesis. In many species this cholesterol is obtained from plasma lipoproteins by a unique pathway in which circulating lipoproteins bind to the surface of the steroidogenic cells and contribute their cholesteryl esters to the cells by a 'selective' process in which the whole lipoprotein particle does not enter the cell. This review describes the lipoprotein selective cholesteryl ester uptake process and its specific partnership with the HDL receptor, scavenger receptor class BI (SR-BI). It describes the characteristics of the selective pathway, and the molecular properties, localization, regulation, anchoring sites and potential mechanisms of action of SR-BI in facilitating cholesteryl ester uptake by steroidogenic cells.
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Affiliation(s)
- Salman Azhar
- Geriatric Research, Education and Clinical Center, GRECC-182B, VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, CA 94304, USA.
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