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Role of ABCA1 in Cardiovascular Disease. J Pers Med 2022; 12:jpm12061010. [PMID: 35743794 PMCID: PMC9225161 DOI: 10.3390/jpm12061010] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 06/17/2022] [Accepted: 06/17/2022] [Indexed: 11/17/2022] Open
Abstract
Cholesterol homeostasis plays a significant role in cardiovascular disease. Previous studies have indicated that ATP-binding cassette transporter A1 (ABCA1) is one of the most important proteins that maintains cholesterol homeostasis. ABCA1 mediates nascent high-density lipoprotein biogenesis. Upon binding with apolipoprotein A-I, ABCA1 facilitates the efflux of excess intracellular cholesterol and phospholipids and controls the rate-limiting step of reverse cholesterol transport. In addition, ABCA1 interacts with the apolipoprotein receptor and suppresses inflammation through a series of signaling pathways. Thus, ABCA1 may prevent cardiovascular disease by inhibiting inflammation and maintaining lipid homeostasis. Several studies have indicated that post-transcriptional modifications play a critical role in the regulation of ABCA1 transportation and plasma membrane localization, which affects its biological function. Meanwhile, carriers of the loss-of-function ABCA1 gene are often accompanied by decreased expression of ABCA1 and an increased risk of cardiovascular diseases. We summarized the ABCA1 transcription regulation mechanism, mutations, post-translational modifications, and their roles in the development of dyslipidemia, atherosclerosis, ischemia/reperfusion, myocardial infarction, and coronary heart disease.
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Chen L, Zhao ZW, Zeng PH, Zhou YJ, Yin WJ. Molecular mechanisms for ABCA1-mediated cholesterol efflux. Cell Cycle 2022; 21:1121-1139. [PMID: 35192423 PMCID: PMC9103275 DOI: 10.1080/15384101.2022.2042777] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The maintenance of cellular cholesterol homeostasis is essential for normal cell function and viability. Excessive cholesterol accumulation is detrimental to cells and serves as the molecular basis of many diseases, such as atherosclerosis, Alzheimer's disease, and diabetes mellitus. The peripheral cells do not have the ability to degrade cholesterol. Cholesterol efflux is therefore the only pathway to eliminate excessive cholesterol from these cells. This process is predominantly mediated by ATP-binding cassette transporter A1 (ABCA1), an integral membrane protein. ABCA1 is known to transfer intracellular free cholesterol and phospholipids to apolipoprotein A-I (apoA-I) for generating nascent high-density lipoprotein (nHDL) particles. nHDL can accept more free cholesterol from peripheral cells. Free cholesterol is then converted to cholesteryl ester by lecithin:cholesterol acyltransferase to form mature HDL. HDL-bound cholesterol enters the liver for biliary secretion and fecal excretion. Although how cholesterol is transported by ABCA1 to apoA-I remains incompletely understood, nine models have been proposed to explain this effect. In this review, we focus on the current view of the mechanisms underlying ABCA1-mediated cholesterol efflux to provide an important framework for future investigation and lipid-lowering therapy.
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Affiliation(s)
- Lei Chen
- Department of Cardiology, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China
| | - Zhen-Wang Zhao
- Institute of Cardiovascular Disease, Key Lab for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Peng-Hui Zeng
- Department of Clinical Laboratory, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Ying-Jie Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Wen-Jun Yin
- Department of Clinical Laboratory, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China,CONTACT Wen-Jun Yin Department of Clinical Laboratory, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan421001, China
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Yu XH, Tang CK. ABCA1, ABCG1, and Cholesterol Homeostasis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1377:95-107. [PMID: 35575923 DOI: 10.1007/978-981-19-1592-5_7] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cholesterol is a major component of mammalian cell membranes and plays important structural and functional roles. However, excessive cholesterol accumulation is toxic to cells and constitutes the molecular basis for many diseases, especially atherosclerotic cardiovascular disease. Thus, cellular cholesterol is tightly regulated to maintain a homeostasis. Reverse cholesterol transport (RCT) is thought to be one primary pathway to eliminate excessive cholesterol from the body. The first and rate-limiting step of RCT is ATP-binding cassette (ABC) transports A1 (ABCA1)- and ABCG1-dependent cholesterol efflux. In the process, ABCA1 mediates initial transport of cellular cholesterol to apolipoprotein A-I (apoA-I) for forming nascent high-density lipoprotein (HDL) particles, and ABCG1 facilitates subsequent continued cholesterol efflux to HDL for further maturation. In this chapter, we summarize the roles of ABCA1 and ABCG1 in maintaining cellular cholesterol homoeostasis and discuss the underlying mechanisms by which they mediate cholesterol export.
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Affiliation(s)
- Xiao-Hua Yu
- Institute of Clinical Medicine, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China
| | - Chao-Ke Tang
- Institute of Cardiovascular Disease, Hengyang Medical School, University of South China, Hengyang, Hunan, China.
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Sterolight as imaging tool to study sterol uptake, trafficking and efflux in living cells. Sci Rep 2022; 12:6264. [PMID: 35428843 PMCID: PMC9012876 DOI: 10.1038/s41598-022-10134-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 03/25/2022] [Indexed: 12/19/2022] Open
Abstract
Information about cholesterol subcellular localization and transport pathways inside cells is essential for understanding and treatment of cholesterol-related diseases. However, there is a lack of reliable tools to monitor it. This work follows the fate of Sterolight, a BODIPY-labelled sterol, within the cell and demonstrates it as a suitable probe for visualization of sterol/lipid trafficking. Sterolight enters cells through an energy-independent process and knockdown experiments suggest caveolin-1 as its potential cellular carrier. Intracellular transport of Sterolight is a rapid process, and transfer from ER and mitochondria to lysosomes and later to lipid droplets requires the participation of active microtubules, as it can be inhibited by the microtubule disruptor nocodazole. Excess of the probe is actively exported from cells, in addition to being stored in lipid droplets, to re-establish the sterol balance. Efflux occurs through a mechanism requiring energy and may be selectively poisoned with verapamil or blocked in cells with mutated cholesterol transporter NPC1. Sterolight is efficiently transferred within and between different cell populations, making it suitable for monitoring numerous aspects of sterol biology, including the live tracking and visualization of intracellular and intercellular transport.
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Chen Y, Yu F, Zhang Y, Li M, Di M, Chen W, Liu X, Zhang Y, Zhang M. Traditional Chinese Medication Tongxinluo Attenuates Lipidosis in Ox-LDL-Stimulated Macrophages by Enhancing Beclin-1-Induced Autophagy. Front Pharmacol 2021; 12:673366. [PMID: 34248627 PMCID: PMC8267176 DOI: 10.3389/fphar.2021.673366] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 06/15/2021] [Indexed: 12/31/2022] Open
Abstract
Tongxinluo (TXL), a traditional Chinese medication, plays a key role in the formation and progression of plaques in atherosclerosis. The formation of foam cells by macrophages accelerates the destabilisation of plaques. In previous research, we had found that TXL significantly inhibits ox-LDL-induced apoptosis in macrophages in vitro by improving the dissociation of the Beclin-1-Bcl-2 complex. Therefore, here, we explored the effect of TXL on lipid metabolism in macrophages and the mechanism involved. To evaluate the role of TXL in atherosclerotic plaques, we construct the atherosclerotic animal model with lentiviral injection and performed immunofluorescence staining analysis in vivo. Western blot, immunofluorescence staining and microscopy were performed to elucidate the mechanism underlying TXL-mediated regulation of autophagy in THP-1 macrophages in vitro. Immunofluorescence assay revealed that TXL treatment inhibited lipid deposition in advanced atherosclerotic plaques. In vitro TXL treatment inhibited lipid deposition in THP-1 macrophages by enhancing autophagy via Beclin-1. TXL reversed the high expression of class I histone deacetylases (HDACs) induced by ox-LDL (p < 0.05). Compared with the TXL + ox-LDL group, TXL failed to promote intracellular lipid droplet decomposition after the addition of the histone deacetylase agonist. We found that TXL attenuates the accumulation of lipids in macrophage by enhancing Beclin-1-induced autophagy, and additionally, it inhibits the inhibitory effect of class I HDAC on the expression of Beclin-1.
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Affiliation(s)
- Yifei Chen
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, China.,Department of Echocardiography, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Fangpu Yu
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, China
| | - Yu Zhang
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, China
| | - Mengmeng Li
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, China
| | - Mingxue Di
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, China
| | - Weijia Chen
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, China
| | - Xiaolin Liu
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, China
| | - Yun Zhang
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, China
| | - Mei Zhang
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, China
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Li H, Yu XH, Ou X, Ouyang XP, Tang CK. Hepatic cholesterol transport and its role in non-alcoholic fatty liver disease and atherosclerosis. Prog Lipid Res 2021; 83:101109. [PMID: 34097928 DOI: 10.1016/j.plipres.2021.101109] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 12/12/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a quickly emerging global health problem representing the most common chronic liver disease in the world. Atherosclerotic cardiovascular disease represents the leading cause of mortality in NAFLD patients. Cholesterol metabolism has a crucial role in the pathogenesis of both NAFLD and atherosclerosis. The liver is the major organ for cholesterol metabolism. Abnormal hepatic cholesterol metabolism not only leads to NAFLD but also drives the development of atherosclerotic dyslipidemia. The cholesterol level in hepatocytes reflects the dynamic balance between endogenous synthesis, uptake, esterification, and export, a process in which cholesterol is converted to neutral cholesteryl esters either for storage in cytosolic lipid droplets or for secretion as a major constituent of plasma lipoproteins, including very-low-density lipoproteins, chylomicrons, high-density lipoproteins, and low-density lipoproteins. In this review, we describe decades of research aimed at identifying key molecules and cellular players involved in each main aspect of hepatic cholesterol metabolism. Furthermore, we summarize the recent advances regarding the biological processes of hepatic cholesterol transport and its role in NAFLD and atherosclerosis.
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Affiliation(s)
- Heng Li
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, University of South China, Hengyang, Hunan 421001, China
| | - Xiao-Hua Yu
- Institute of Clinical Medicine, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan 460106, China
| | - Xiang Ou
- Department of Endocrinology, the First Hospital of Changsha, Changsha, Hunan 410005, China
| | - Xin-Ping Ouyang
- Department of Physiology, Institute of Neuroscience Research, Hengyang Key Laboratory of Neurodegeneration and Cognitive Impairment, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, University of South China, Hengyang, Hunan 421001, China.
| | - Chao-Ke Tang
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, University of South China, Hengyang, Hunan 421001, China.
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8
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Castaño D, Rattanasopa C, Monteiro-Cardoso VF, Corlianò M, Liu Y, Zhong S, Rusu M, Liehn EA, Singaraja RR. Lipid efflux mechanisms, relation to disease and potential therapeutic aspects. Adv Drug Deliv Rev 2020; 159:54-93. [PMID: 32423566 DOI: 10.1016/j.addr.2020.04.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/29/2020] [Accepted: 04/30/2020] [Indexed: 02/06/2023]
Abstract
Lipids are hydrophobic and amphiphilic molecules involved in diverse functions such as membrane structure, energy metabolism, immunity, and signaling. However, altered intra-cellular lipid levels or composition can lead to metabolic and inflammatory dysfunction, as well as lipotoxicity. Thus, intra-cellular lipid homeostasis is tightly regulated by multiple mechanisms. Since most peripheral cells do not catabolize cholesterol, efflux (extra-cellular transport) of cholesterol is vital for lipid homeostasis. Defective efflux contributes to atherosclerotic plaque development, impaired β-cell insulin secretion, and neuropathology. Of these, defective lipid efflux in macrophages in the arterial walls leading to foam cell and atherosclerotic plaque formation has been the most well studied, likely because a leading global cause of death is cardiovascular disease. Circulating high density lipoprotein particles play critical roles as acceptors of effluxed cellular lipids, suggesting their importance in disease etiology. We review here mechanisms and pathways that modulate lipid efflux, the role of lipid efflux in disease etiology, and therapeutic options aimed at modulating this critical process.
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Abstract
Cardiovascular disease, with atherosclerosis as the major underlying factor, remains the leading cause of death worldwide. It is well established that cholesterol ester-enriched foam cells are the hallmark of atherosclerotic plaques. Multiple lines of evidence support that enhancing foam cell cholesterol efflux by HDL (high-density lipoprotein) particles, the first step of reverse cholesterol transport (RCT), is a promising antiatherogenic strategy. Yet, excitement towards the therapeutic potential of manipulating RCT for the treatment of cardiovascular disease has faded because of the lack of the association between cardiovascular disease risk and what was typically measured in intervention trials, namely HDL cholesterol, which has an inconsistent relationship to HDL function and RCT. In this review, we will summarize some of the potential reasons for this inconsistency, update the mechanisms of RCT, and highlight conditions in which impaired HDL function or RCT contributes to vascular disease. On balance, the evidence still argues for further research to better understand how HDL functionality contributes to RCT to develop prevention and treatment strategies to reduce the risk of cardiovascular disease.
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Affiliation(s)
- Mireille Ouimet
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa Heart Institute, University of Ottawa, Canada (M.O.)
| | - Tessa J Barrett
- Division of Cardiology, Department of Medicine, New York University School of Medicine, New York (T.J.B., E.A.F.)
| | - Edward A Fisher
- Division of Cardiology, Department of Medicine, New York University School of Medicine, New York (T.J.B., E.A.F.)
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10
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ABC Transporters, Cholesterol Efflux, and Implications for Cardiovascular Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1276:67-83. [DOI: 10.1007/978-981-15-6082-8_6] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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11
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Schultz ML, Fawaz MV, Azaria RD, Hollon TC, Liu EA, Kunkel TJ, Halseth TA, Krus KL, Ming R, Morin EE, McLoughlin HS, Bushart DD, Paulson HL, Shakkottai VG, Orringer DA, Schwendeman AS, Lieberman AP. Synthetic high-density lipoprotein nanoparticles for the treatment of Niemann-Pick diseases. BMC Med 2019; 17:200. [PMID: 31711490 PMCID: PMC6849328 DOI: 10.1186/s12916-019-1423-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 09/10/2019] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Niemann-Pick disease type C is a fatal and progressive neurodegenerative disorder characterized by the accumulation of unesterified cholesterol in late endosomes and lysosomes. We sought to develop new therapeutics for this disorder by harnessing the body's endogenous cholesterol scavenging particle, high-density lipoprotein (HDL). METHODS Here we design, optimize, and define the mechanism of action of synthetic HDL (sHDL) nanoparticles. RESULTS We demonstrate a dose-dependent rescue of cholesterol storage that is sensitive to sHDL lipid and peptide composition, enabling the identification of compounds with a range of therapeutic potency. Peripheral administration of sHDL to Npc1 I1061T homozygous mice mobilizes cholesterol, reduces serum bilirubin, reduces liver macrophage size, and corrects body weight deficits. Additionally, a single intraventricular injection into adult Npc1 I1061T brains significantly reduces cholesterol storage in Purkinje neurons. Since endogenous HDL is also a carrier of sphingomyelin, we tested the same sHDL formulation in the sphingomyelin storage disease Niemann-Pick type A. Utilizing stimulated Raman scattering microscopy to detect endogenous unlabeled lipids, we show significant rescue of Niemann-Pick type A lipid storage. CONCLUSIONS Together, our data establish that sHDL nanoparticles are a potential new therapeutic avenue for Niemann-Pick diseases.
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Affiliation(s)
- Mark L Schultz
- Department of Pathology, University of Michigan Medical School, 3510 MSRB1, 1150 W. Medical Center Dr., Ann Arbor, MI, 48109, USA
| | - Maria V Fawaz
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Ruth D Azaria
- Department of Pathology, University of Michigan Medical School, 3510 MSRB1, 1150 W. Medical Center Dr., Ann Arbor, MI, 48109, USA
| | - Todd C Hollon
- Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Elaine A Liu
- Department of Pathology, University of Michigan Medical School, 3510 MSRB1, 1150 W. Medical Center Dr., Ann Arbor, MI, 48109, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
- Medical Scientist Training Program, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Thaddeus J Kunkel
- Department of Pathology, University of Michigan Medical School, 3510 MSRB1, 1150 W. Medical Center Dr., Ann Arbor, MI, 48109, USA
| | - Troy A Halseth
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Kelsey L Krus
- Department of Pathology, University of Michigan Medical School, 3510 MSRB1, 1150 W. Medical Center Dr., Ann Arbor, MI, 48109, USA
| | - Ran Ming
- Department of Pharmaceutical Sciences, University of Michigan College of Pharmacy, B20-102W NCRC, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
| | - Emily E Morin
- Department of Pharmaceutical Sciences, University of Michigan College of Pharmacy, B20-102W NCRC, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
| | - Hayley S McLoughlin
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - David D Bushart
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Henry L Paulson
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Vikram G Shakkottai
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Daniel A Orringer
- Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Anna S Schwendeman
- Department of Pharmaceutical Sciences, University of Michigan College of Pharmacy, B20-102W NCRC, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA.
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Andrew P Lieberman
- Department of Pathology, University of Michigan Medical School, 3510 MSRB1, 1150 W. Medical Center Dr., Ann Arbor, MI, 48109, USA.
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Lorkowski SW, Brubaker G, Gulshan K, Smith JD. V-ATPase (Vacuolar ATPase) Activity Required for ABCA1 (ATP-Binding Cassette Protein A1)-Mediated Cholesterol Efflux. Arterioscler Thromb Vasc Biol 2019; 38:2615-2625. [PMID: 30354238 DOI: 10.1161/atvbaha.118.311814] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective- We have shown that ABCA1 (ATP-binding cassette protein A1) mediates unfolding of the apoA1 (apolipoprotein A1) N-terminal helical hairpin during apoA1 lipidation. Others have shown that an acidic pH exposes the hydrophobic surface of apoA1. We postulated that the V-ATPase (vacuolar ATPase) proton pump facilitates apoA1 unfolding and promotes ABCA1-mediated cholesterol efflux. Approach and Results- We found that V-ATPase inhibitors dose-dependently decreased ABCA1-mediated cholesterol efflux to apoA1 in baby hamster kidney cells and RAW264.7 cells; and similarly, siRNA knockdown of ATP6V0C inhibited ABCA1-mediated cholesterol efflux to apoA1 in RAW264.7 cells. Although ABCA1 expression did not alter total cellular levels of V-ATPase, ABCA1 increased the cell surface levels of the V0A1 and V1E1 subunits of V-ATPase. We generated a fluorescein isothiocyanate/Alexa647 double-labeled fluorescent ratiometric apoA1 pH indicator whose fluorescein isothiocyanate/Alexa647 emission ratio decreased as the pH drops. We found that ABCA1 induction in baby hamster kidney cells led to acidification of the cell-associated apoA1 pH indicator, compared with control cells without ABCA1 expression. The V-ATPase inhibitor bafilomycin A1 dose-dependently inhibited the apoA1 pH shift in ABCA1-expressing cells, without affecting the levels of cell-associated apoA1. However, we were not able to detect ABCA1-mediated extracellular proton release. We showed that acidic pH facilitated apoA1 unfolding, apoA1 solubilization of phosphatidycholine:phosphatidyserine liposomes, and increased lipid fluidity of these liposomes. Conclusions- Our results support a model that ABCA1 recruits V-ATPase to the plasma membrane where V-ATPase mediates apoA1 acidification and membrane remodeling that promote apoA1 unfolding and ABCA1-mediated HDL (high-density lipoprotein) biogenesis and lipid efflux.
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Affiliation(s)
- Shuhui Wang Lorkowski
- From the Department of Cellular and Molecular Medicine (S.W.L., G.B., K.G., J.D.S.), Cleveland Clinic, OH
| | - Gregory Brubaker
- From the Department of Cellular and Molecular Medicine (S.W.L., G.B., K.G., J.D.S.), Cleveland Clinic, OH
| | - Kailash Gulshan
- From the Department of Cellular and Molecular Medicine (S.W.L., G.B., K.G., J.D.S.), Cleveland Clinic, OH
| | - Jonathan D Smith
- From the Department of Cellular and Molecular Medicine (S.W.L., G.B., K.G., J.D.S.), Cleveland Clinic, OH.,Department of Cardiovascular Medicine (J.D.S.), Cleveland Clinic, OH
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13
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Otis JP, Shen MC, Caldwell BA, Reyes Gaido OE, Farber SA. Dietary cholesterol and apolipoprotein A-I are trafficked in endosomes and lysosomes in the live zebrafish intestine. Am J Physiol Gastrointest Liver Physiol 2019; 316:G350-G365. [PMID: 30629468 PMCID: PMC6415739 DOI: 10.1152/ajpgi.00080.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Difficulty in imaging the vertebrate intestine in vivo has hindered our ability to model nutrient and protein trafficking from both the lumenal and basolateral aspects of enterocytes. Our goal was to use live confocal imaging to increase understanding of intestinal trafficking of dietary cholesterol and apolipoprotein A-I (APOA-I), the main structural component of high-density lipoproteins. We developed a novel assay to visualize live dietary cholesterol trafficking in the zebrafish intestine by feeding TopFluor-cholesterol (TF-cholesterol), a fluorescent cholesterol analog, in a lipid-rich, chicken egg yolk feed. Quantitative microscopy of transgenic zebrafish expressing fluorescently tagged protein markers of early, recycling, and late endosomes/lysosomes provided the first evidence, to our knowledge, of cholesterol transport in the intestinal endosomal-lysosomal trafficking system. To study APOA-I dynamics, transgenic zebrafish expressing an APOA-I fluorescent fusion protein (APOA-I-mCherry) from tissue-specific promoters were created. These zebrafish demonstrated that APOA-I-mCherry derived from the intestine accumulated in the liver and vice versa. Additionally, intracellular APOA-I-mCherry localized to endosomes and lysosomes in the intestine and liver. Moreover, live imaging demonstrated that APOA-I-mCherry colocalized with dietary TF-cholesterol in enterocytes, and this colocalization increased with feeding time. This study provides a new set of tools for the study of cellular lipid biology and elucidates a key role for endosomal-lysosomal trafficking of intestinal cholesterol and APOA-I. NEW & NOTEWORTHY A fluorescent cholesterol analog was fed to live, translucent larval zebrafish to visualize intracellular cholesterol and apolipoprotein A-I (APOA-I) trafficking. With this model intestinal endosomal-lysosomal cholesterol trafficking was observed for the first time. A new APOA-I fusion protein (APOA-I-mCherry) expressed from tissue-specific promoters was secreted into the circulation and revealed that liver-derived APOA-I-mCherry accumulates in the intestine and vice versa. Intestinal, intracellular APOA-I-mCherry was observed in endosomes and lysosomes and colocalized with dietary cholesterol.
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Affiliation(s)
- Jessica P. Otis
- 1Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland
| | - Meng-Chieh Shen
- 1Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland
| | - Blake A. Caldwell
- 1Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland
| | - Oscar E. Reyes Gaido
- 1Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland,2Department of Biology, Johns Hopkins University, Baltimore, Maryland
| | - Steven A. Farber
- 1Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland,2Department of Biology, Johns Hopkins University, Baltimore, Maryland
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14
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Abstract
Measuring cholesterol efflux involves the tracking of cholesterol movement out of cells. Cholesterol efflux is an essential mechanism to maintain cellular cholesterol homeostasis, and this process is largely regulated via the LXR transcription factors and their regulated genes, the ATP-binding cassette (ABC) cholesterol transporters ABCA1 and ABCG1. Typically, efflux assays are performed utilizing radiolabeled cholesterol tracers to label intracellular cholesterol pools, and these assays may be tailored to quantify the efflux of exogenously delivered cholesterol or alternatively the efflux of newly synthesized (endogenous) cholesterol, in different cell types (macrophages, hepatocytes). Cholesterol efflux may also be customized to quantify cholesterol flux out of the cell to various exogenous cholesterol acceptors, such as apolipoprotein A-I, high-density lipoprotein, or methyl-beta-cyclodextrin, depending on the purpose of the experiment. Here, we provide comprehensive protocols to quantify the net flux of cholesterol out of cells and recommendations on how this assay may be tailored as a function of the experimental question at hand.
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15
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Yu XH, Zhang DW, Zheng XL, Tang CK. Cholesterol transport system: An integrated cholesterol transport model involved in atherosclerosis. Prog Lipid Res 2018; 73:65-91. [PMID: 30528667 DOI: 10.1016/j.plipres.2018.12.002] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 10/30/2018] [Accepted: 12/01/2018] [Indexed: 02/07/2023]
Abstract
Atherosclerosis, the pathological basis of most cardiovascular disease (CVD), is closely associated with cholesterol accumulation in the arterial intima. Excessive cholesterol is removed by the reverse cholesterol transport (RCT) pathway, representing a major antiatherogenic mechanism. In addition to the RCT, other pathways are required for maintaining the whole-body cholesterol homeostasis. Thus, we propose a working model of integrated cholesterol transport, termed the cholesterol transport system (CTS), to describe body cholesterol metabolism. The novel model not only involves the classical view of RCT but also contains other steps, such as cholesterol absorption in the small intestine, low-density lipoprotein uptake by the liver, and transintestinal cholesterol excretion. Extensive studies have shown that dysfunctional CTS is one of the major causes for hypercholesterolemia and atherosclerosis. Currently, several drugs are available to improve the CTS efficiently. There are also several therapeutic approaches that have entered into clinical trials and shown considerable promise for decreasing the risk of CVD. In recent years, a variety of novel findings reveal the molecular mechanisms for the CTS and its role in the development of atherosclerosis, thereby providing novel insights into the understanding of whole-body cholesterol transport and metabolism. In this review, we summarize the latest advances in this area with an emphasis on the therapeutic potential of targeting the CTS in CVD patients.
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Affiliation(s)
- Xiao-Hua Yu
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Medical Research Experiment Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, China
| | - Da-Wei Zhang
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada
| | - Xi-Long Zheng
- Department of Biochemistry and Molecular Biology, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Health Sciences Center, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
| | - Chao-Ke Tang
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Medical Research Experiment Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, China.
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16
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Intracellular and Plasma Membrane Events in Cholesterol Transport and Homeostasis. J Lipids 2018; 2018:3965054. [PMID: 30174957 PMCID: PMC6106919 DOI: 10.1155/2018/3965054] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 07/26/2018] [Indexed: 12/13/2022] Open
Abstract
Cholesterol transport between intracellular compartments proceeds by both energy- and non-energy-dependent processes. Energy-dependent vesicular traffic partly contributes to cholesterol flux between endoplasmic reticulum, plasma membrane, and endocytic vesicles. Membrane contact sites and lipid transfer proteins are involved in nonvesicular lipid traffic. Only “active" cholesterol molecules outside of cholesterol-rich regions and partially exposed in water phase are able to fast transfer. The dissociation of partially exposed cholesterol molecules in water determines the rate of passive aqueous diffusion of cholesterol out of plasma membrane. ATP hydrolysis with concomitant conformational transition is required to cholesterol efflux by ABCA1 and ABCG1 transporters. Besides, scavenger receptor SR-B1 is involved also in cholesterol efflux by facilitated diffusion via hydrophobic tunnel within the molecule. Direct interaction of ABCA1 with apolipoprotein A-I (apoA-I) or apoA-I binding to high capacity binding sites in plasma membrane is important in cholesterol escape to free apoA-I. ABCG1-mediated efflux to fully lipidated apoA-I within high density lipoprotein particle proceeds more likely through the increase of “active” cholesterol level. Putative cholesterol-binding linear motifs within the structure of all three proteins ABCA1, ABCG1, and SR-B1 are suggested to contribute to the binding and transfer of cholesterol molecules from cytoplasmic to outer leaflets of lipid bilayer. Together, plasma membrane events and intracellular cholesterol metabolism and traffic determine the capacity of the cell for cholesterol efflux.
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17
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Ebner L, Gläser A, Bräuer A, Witt M, Wree A, Rolfs A, Frank M, Vollmar B, Kuhla A. Evaluation of Two Liver Treatment Strategies in a Mouse Model of Niemann-Pick-Disease Type C1. Int J Mol Sci 2018; 19:ijms19040972. [PMID: 29587349 PMCID: PMC5979582 DOI: 10.3390/ijms19040972] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 03/14/2018] [Accepted: 03/20/2018] [Indexed: 11/16/2022] Open
Abstract
Niemann–Pick-disease type C1 (NPC1) is an autosomal-recessive cholesterol-storage disorder. Besides other symptoms, NPC1 patients develop liver dysfunction and hepatosplenomegaly. The mechanisms of hepatomegaly and alterations of lipid metabolism-related genes in NPC1 disease are still poorly understood. Here, we used an NPC1 mouse model to study an additive hepatoprotective effect of a combination of 2-hydroxypropyl-β-cyclodextrin (HPβCD), miglustat and allopregnanolone (combination therapy) with the previously established monotherapy using HPβCD. We examined transgene effects as well as treatment effects on liver morphology and hepatic lipid metabolism, focusing on hepatic cholesterol transporter genes. Livers of Npc1−/− mice showed hepatic cholesterol sequestration with consecutive liver injury, an increase of lipogenetic gene expression, e.g., HMG-CoA, a decrease of lipolytic gene expression, e.g., pparα and acox1, and a decrease of lipid transporter gene expression, e.g., acat1, abca1 and fatp2. Both, combination therapy and monotherapy, led to a reduction of hepatic lipids and an amelioration of NPC1 liver disease symptoms. Monotherapy effects were related to pparα- and acox1-associated lipolysis/β-oxidation and to fatp2-induced fatty acid transport, whereas the combination therapy additionally increased the cholesterol transport via abca1 and apoE. However, HPβCD monotherapy additionally increased cholesterol synthesis as indicated by a marked increase of the HMG-CoA and srebp-2 mRNA expression, probably as a result of increased hepatocellular proliferation.
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Affiliation(s)
- Lynn Ebner
- Institute for Experimental Surgery, Rostock University Medical Center, Schillingallee 69a, 18057 Rostock, Germany.
| | - Anne Gläser
- Institute of Anatomy, Rostock University Medical Center, Gertrudenstraße 9, 18057 Rostock, Germany.
| | - Anja Bräuer
- Institute of Anatomy, Rostock University Medical Center, Gertrudenstraße 9, 18057 Rostock, Germany.
| | - Martin Witt
- Institute of Anatomy, Rostock University Medical Center, Gertrudenstraße 9, 18057 Rostock, Germany.
| | - Andreas Wree
- Institute of Anatomy, Rostock University Medical Center, Gertrudenstraße 9, 18057 Rostock, Germany.
| | - Arndt Rolfs
- Albrecht Kossel Institute for Neuroregeneration, Rostock University Medical Center, Gehlsheimer Straße 20, 18147 Rostock, Germany.
| | - Marcus Frank
- Medical Biology and Electron Microscopy Center, Rostock University Medical Center, 18057 Rostock, Germany.
| | - Brigitte Vollmar
- Institute for Experimental Surgery, Rostock University Medical Center, Schillingallee 69a, 18057 Rostock, Germany.
| | - Angela Kuhla
- Institute for Experimental Surgery, Rostock University Medical Center, Schillingallee 69a, 18057 Rostock, Germany.
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18
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Phillips MC. Is ABCA1 a lipid transfer protein? J Lipid Res 2018; 59:749-763. [PMID: 29305383 DOI: 10.1194/jlr.r082313] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/02/2018] [Indexed: 12/16/2022] Open
Abstract
ABCA1 functions as a lipid transporter because it mediates the transfer of cellular phospholipid (PL) and free (unesterified) cholesterol (FC) to apoA-I and related proteins present in the extracellular medium. ABCA1 is a membrane PL translocase and its enzymatic activity leads to transfer of PL molecules from the cytoplasmic leaflet to the exofacial leaflet of a cell plasma membrane (PM). The presence of active ABCA1 in the PM promotes binding of apoA-I to the cell surface. About 10% of this bound apoA-I interacts directly with ABCA1 and stabilizes the transporter. Most of the pool of cell surface-associated apoA-I is bound to lipid domains in the PM that are created by the activity of ABCA1. The amphipathic α-helices in apoA-I confer detergent-like properties on the protein enabling it to solubilize PL and FC in these membrane domains to create a heterogeneous population of discoidal nascent HDL particles. This review focuses on current understanding of the structure-function relationships of human ABCA1 and the molecular mechanisms underlying HDL particle production.
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Affiliation(s)
- Michael C Phillips
- Division of Translational Medicine and Human Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-5158
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19
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Yamauchi Y, Rogers MA. Sterol Metabolism and Transport in Atherosclerosis and Cancer. Front Endocrinol (Lausanne) 2018; 9:509. [PMID: 30283400 PMCID: PMC6157400 DOI: 10.3389/fendo.2018.00509] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/14/2018] [Indexed: 01/22/2023] Open
Abstract
Cholesterol is a vital lipid molecule for mammalian cells, regulating fluidity of biological membranes, and serving as an essential constituent of lipid rafts. Mammalian cells acquire cholesterol from extracellular lipoproteins and from de novo synthesis. Cholesterol biosynthesis generates various precursor sterols. Cholesterol undergoes metabolic conversion into oxygenated sterols (oxysterols), bile acids, and steroid hormones. Cholesterol intermediates and metabolites have diverse and important cellular functions. A network of molecular machineries including transcription factors, protein modifiers, sterol transporters/carriers, and sterol sensors regulate sterol homeostasis in mammalian cells and tissues. Dysfunction in metabolism and transport of cholesterol, sterol intermediates, and oxysterols occurs in various pathophysiological settings such as atherosclerosis, cancers, and neurodegenerative diseases. Here we review the cholesterol, intermediate sterol, and oxysterol regulatory mechanisms and intracellular transport machineries, and discuss the roles of sterols and sterol metabolism in human diseases.
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Affiliation(s)
- Yoshio Yamauchi
- Nutri-Life Science Laboratory, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
- AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, Japan
- *Correspondence: Yoshio Yamauchi
| | - Maximillian A. Rogers
- Division of Cardiovascular Medicine, Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
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20
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Role of 6-O-α-maltosyl-β-cyclodextrin in lysosomal cholesterol deprivation in Npc1-deficient Chinese hamster ovary cells. Carbohydr Res 2018; 455:54-61. [DOI: 10.1016/j.carres.2017.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 10/31/2017] [Accepted: 11/08/2017] [Indexed: 11/17/2022]
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21
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Placental ABCA1 Expression Is Increased in Spontaneous Preterm Deliveries Compared with Iatrogenic Preterm Deliveries and Term Deliveries. BIOMED RESEARCH INTERNATIONAL 2017. [PMID: 28630870 PMCID: PMC5467290 DOI: 10.1155/2017/8248094] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Objective Abnormal expression of ABCA1 and ABCG1 in the placenta can elicit lipid metabolism disorder and adverse pregnancy outcomes. However, whether it is associated with preterm delivery remains unclear. Our present study aimed to evaluate the relationship between abnormal expression of ABCA1 or ABCG1 and preterm delivery. Methods Maternal blood and placental tissues from women with spontaneous deliveries (SPD), iatrogenic deliveries (IPD), and term deliveries (TD) were collected. The lipid content and expression of ABCA1 and ABCG1 were subsequently measured. Results Compared with IPD and TD groups, the HDL, TD, LDL, and TC levels were lower in the maternal blood but higher (except TC) in the cord blood of the SPD group. The extracellular lipid content in the placentas of the SPD group was also notably lower relative to the IPD and TD groups. Moreover, the protein and mRNA expressions of ABCA1 in the placentas of the SPD group were significantly higher compared with the IPD and TD groups; however, there was no obvious difference among the three groups in the protein and mRNA expressions of ABCG1. Conclusions Abnormal expression of ABCA1 may be associated with the dysregulation of placental lipid metabolism and the occurrence or development of SPD.
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22
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Ontsouka CE, Huang X, Aliyev E, Albrecht C. In vitro characterization and endocrine regulation of cholesterol and phospholipid transport in the mammary gland. Mol Cell Endocrinol 2017; 439:35-45. [PMID: 27760380 DOI: 10.1016/j.mce.2016.10.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/25/2016] [Accepted: 10/15/2016] [Indexed: 10/20/2022]
Abstract
Cell-based studies previously showed that the ATP-binding cassette transporter A1 (ABCA1) transfers cholesterol across mammary epithelial cells (MEC). Data for phospholipid transport are lacking, and it is unclear from which cellular source the transported cholesterol stems, whether this transport activates signaling pathways, and how lactogenic hormones regulate it. To clarify these aspects, lipid transport and expressional analyses were performed in bovine primary (bMEC) and/or immortalized (MAC-T) MEC cultures. Lipid efflux and ABCA1, ABCG1 and liver X receptorα mRNA levels were higher in MAC-T than bMEC. In MAC-T, the transported cholesterol originated mainly from the plasma membrane. ABCA1 dependent cholesterol efflux was higher than phosphatidylcholine efflux, was suppressed by probucol (ABCA1 inhibitor), AG490 (janus kinase-2 inhibitor), PD98059 (mitogen activated protein kinase kinase inhibitor) and pretreatment with β-cyclodextrin (lowering membrane cholesterol). Insulin was the only hormone significantly increasing cholesterol efflux. In conclusion, this study gives novel mechanistic and regulatory insights into the transport of cholesterol and phospholipids in MEC.
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Affiliation(s)
- Corneille Edgar Ontsouka
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, 3012, Bern, Switzerland; Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland
| | - Xiao Huang
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, 3012, Bern, Switzerland; Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland
| | - Eldar Aliyev
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, 3012, Bern, Switzerland
| | - Christiane Albrecht
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, 3012, Bern, Switzerland; Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland.
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23
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Jin X, Sviridov D, Liu Y, Vaisman B, Addadi L, Remaley AT, Kruth HS. ABCA1 (ATP-Binding Cassette Transporter A1) Mediates ApoA-I (Apolipoprotein A-I) and ApoA-I Mimetic Peptide Mobilization of Extracellular Cholesterol Microdomains Deposited by Macrophages. Arterioscler Thromb Vasc Biol 2016; 36:2283-2291. [PMID: 27758769 DOI: 10.1161/atvbaha.116.308334] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 09/02/2016] [Indexed: 11/16/2022]
Abstract
OBJECTIVE We examined the function of ABCA1 (ATP-binding cassette transporter A1) in ApoA-I (apolipoprotein A-I) mobilization of cholesterol microdomains deposited into the extracellular matrix by cholesterol-enriched macrophages. We have also determined whether an ApoA-I mimetic peptide without and with complexing to sphingomyelin can mobilize macrophage-deposited cholesterol microdomains. APPROACH AND RESULTS Extracellular cholesterol microdomains deposited by cholesterol-enriched macrophages were detected with a monoclonal antibody, 58B1. ApoA-I and an ApoA-I mimetic peptide 5A mobilized cholesterol microdomains deposited by ABCA1+/+ macrophages but not by ABCA1-/- macrophages. In contrast, ApoA-I mimetic peptide 5A complexed with sphingomyelin could mobilize cholesterol microdomains deposited by ABCA1-/- macrophages. CONCLUSIONS Our findings show that a unique pool of extracellular cholesterol microdomains deposited by macrophages can be mobilized by both ApoA-I and an ApoA-I mimetic peptide but that mobilization depends on macrophage ABCA1. It is known that ABCA1 complexes ApoA-I and ApoA-I mimetic peptide with phospholipid, a cholesterol-solubilizing agent, explaining the requirement for ABCA1 in extracellular cholesterol microdomain mobilization. Importantly, ApoA-I mimetic peptide already complexed with phospholipid can mobilize macrophage-deposited extracellular cholesterol microdomains even in the absence of ABCA1.
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Affiliation(s)
- Xueting Jin
- From the Experimental Atherosclerosis Section (X.J., Y.L., H.S.K.) and Lipoprotein Metabolism Section (D.S., B.V., A.T.R.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel (L.A.)
| | - Denis Sviridov
- From the Experimental Atherosclerosis Section (X.J., Y.L., H.S.K.) and Lipoprotein Metabolism Section (D.S., B.V., A.T.R.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel (L.A.)
| | - Ying Liu
- From the Experimental Atherosclerosis Section (X.J., Y.L., H.S.K.) and Lipoprotein Metabolism Section (D.S., B.V., A.T.R.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel (L.A.)
| | - Boris Vaisman
- From the Experimental Atherosclerosis Section (X.J., Y.L., H.S.K.) and Lipoprotein Metabolism Section (D.S., B.V., A.T.R.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel (L.A.)
| | - Lia Addadi
- From the Experimental Atherosclerosis Section (X.J., Y.L., H.S.K.) and Lipoprotein Metabolism Section (D.S., B.V., A.T.R.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel (L.A.)
| | - Alan T Remaley
- From the Experimental Atherosclerosis Section (X.J., Y.L., H.S.K.) and Lipoprotein Metabolism Section (D.S., B.V., A.T.R.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel (L.A.)
| | - Howard S Kruth
- From the Experimental Atherosclerosis Section (X.J., Y.L., H.S.K.) and Lipoprotein Metabolism Section (D.S., B.V., A.T.R.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel (L.A.).
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24
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Yamauchi Y, Yokoyama S, Chang TY. ABCA1-dependent sterol release: sterol molecule specificity and potential membrane domain for HDL biogenesis. J Lipid Res 2015; 57:77-88. [PMID: 26497474 DOI: 10.1194/jlr.m063784] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Indexed: 01/28/2023] Open
Abstract
Mammalian cells synthesize various sterol molecules, including the C30 sterol, lanosterol, as cholesterol precursors in the endoplasmic reticulum. The build-up of precursor sterols, including lanosterol, displays cellular toxicity. Precursor sterols are found in plasma HDL. How these structurally different sterols are released from cells is poorly understood. Here, we show that newly synthesized precursor sterols arriving at the plasma membrane (PM) are removed by extracellular apoA-I in a manner dependent on ABCA1, a key macromolecule for HDL biogenesis. Analysis of sterol molecules by GC-MS and tracing the fate of radiolabeled acetate-derived sterols in normal and mutant Niemann-Pick type C cells reveal that ABCA1 prefers newly synthesized sterols, especially lanosterol, as the substrates before they are internalized from the PM. We also show that ABCA1 resides in a cholesterol-rich membrane domain resistant to the mild detergent, Brij 98. Blocking ACAT activity increases the cholesterol contents of this domain. Newly synthesized C29/C30 sterols are transiently enriched within this domain, but rapidly disappear from this domain with a half-life of less than 1 h. Our work shows that substantial amounts of precursor sterols are transported to a certain PM domain and are removed by the ABCA1-dependent pathway.
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Affiliation(s)
- Yoshio Yamauchi
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Shinji Yokoyama
- Nutritional Health Science Research Center and Department of Food and Nutritional Sciences, Chubu University, Kasugai 487-8501, Japan
| | - Ta-Yuan Chang
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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25
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Okoro EU, Zhang H, Guo Z, Yang F, Smith C, Yang H. A Subregion of Reelin Suppresses Lipoprotein-Induced Cholesterol Accumulation in Macrophages. PLoS One 2015; 10:e0136895. [PMID: 26317415 PMCID: PMC4552883 DOI: 10.1371/journal.pone.0136895] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 08/10/2015] [Indexed: 11/18/2022] Open
Abstract
Activation of apolipoprotein E receptor-2 (apoER2) and very low density lipoprotein receptor (VLDLR) inhibits foam cell formation. Reelin is a ligand of these receptors. Here we generated two reelin subregions containing the receptor binding domain with or without its C-terminal region (R5-6C and R5-6, respectively) and studied the impact of these peptides on macrophage cholesterol metabolism. We found that both R5-6C and R5-6 can be secreted by cells. Purified R5-6 protein can bind apoER2 and VLDLR. Overexpression of apoER2 in macrophages increased the amount of R5-6 bound to the cell surface. Treatment of macrophages with 0.2 μg/ml R5-6 elevated ATP binding cassette A1 (ABCA1) protein level by ~72% and apoAI-mediated cholesterol efflux by ~39%. In addition, the medium harvested from cells overexpressing R5-6 or R5-6C (R5-6- and R5-6C-conditioned media, respectively) also up-regulated ABCA1 protein expression, which was associated with accelerated cholesterol efflux and enhanced phosphorylation of phosphatidylinositol 3 kinase (PI3K) and specificity protein-1 (Sp1) in macrophages. The increased ABCA1 expression and cholesterol efflux by R5-6- and R5-6C-conditioned media were diminished by Sp1 or PI3K inhibitors mithramycin A and LY294002. Further, the cholesterol accumulation induced by apoB-containing, apoE-free lipoproteins was significantly less in macrophages incubated with R5-6- or R5-6C-conditioned medium than in those incubated with control conditioned medium. Knockdown of apoER2 or VLDLR attenuated the inhibitory role of R5-6-conditioned medium against lipoprotein-induced cholesterol accumulation. These results suggest that the reelin subregion R5-6 can serve as a tool for studying the role of apoER2 and VLDLR in atherogenesis.
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Affiliation(s)
- Emmanuel U. Okoro
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - Hongfeng Zhang
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
- Department of Pathology, Central Hospital of Wuhan, Wuhan City, People’s Republic of China
| | - Zhongmao Guo
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - Fang Yang
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
- Wuhan University School of Basic Medical Science, Wuhan City, People’s Republic of China
| | - Carlie Smith
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - Hong Yang
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
- * E-mail:
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26
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Abstract
ABCA1 mediates the secretion of cellular free cholesterol and phospholipids to an extracellular acceptor, apolipoprotein AI, to form nascent high-density lipoprotein (HDL). Thus, ABCA1 is a key molecule in cholesterol homeostasis. Functional studies of certain Tangier disease mutations demonstrate that ABCA1 has multiple activities, including plasma membrane remodeling and apoAI binding to cell surface, which participate in nascent HDL biogenesis. Recent advances in our understanding of ABCA1 have demonstrated that ABCA1also mediates unfolding the N terminus of apoAI on the cell surface, followed by lipidation of apoAI and release of nascent HDL. Although ABCA1-mediated cholesterol efflux to apoAI can occur on the plasma membrane, the role of apoAI retroendocytosis during cholesterol efflux may play a role in macrophage foam cells that store cholesterol esters in cytoplasmic lipid droplets.
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Affiliation(s)
- Shuhui Wang
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland OH 44195, USA
| | - Jonathan D. Smith
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland OH 44195, USA
- Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland OH 44195, USA
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27
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ApoA-I/HDL Generation and Intracellular Cholesterol Transport through Cytosolic Lipid-Protein Particles in Astrocytes. J Lipids 2014; 2014:530720. [PMID: 25197575 PMCID: PMC4146353 DOI: 10.1155/2014/530720] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 06/24/2014] [Indexed: 01/24/2023] Open
Abstract
Exogenous apolipoprotein A-I (apoA-I) associates with ATP-binding cassette transporter A1 (ABCA1) on the cell surface of astrocytes like various peripheral cells and enhances the translocation of newly synthesized cholesterol from the endoplasmic reticulum/Golgi apparatus (ER/Golgi) to the cytosol. The cholesterol translocated to the cytosol is incorporated to cytosolic lipid-protein particles (CLPP) together with phospholipids and proteins such as sphingomyelin, phosphatidylcholine, caveolin-1, protein kinase Cα (PK-Cα), and cyclophilin A. The CLPP are high density lipoproteins- (HDL-)like cytosolic lipid-protein complex with densities of 1.09–1.16 g/mL and diameters of 17-18 nm. The association of exogenous apoA-I with cellular ABCA1 induces tyrosine phosphorylation, activation, and translocation to the CLPP of ABCA1-associated phospholipase Cγ (PL-Cγ) in rat astrocytes. Furthermore, PK-Cα is translocated and activated to/in the CLPP through theproduction of diacylglyceride in the CLPP. ApoA-I enhances both the association of CLPP with microtubules and the phosphorylation of α-tubulin as a component of microtubules. The CLPP are dissociated from microtubules after α-tubulin in microtubules is phosphorylated by the CLPP-associated PK-Cα. The association and dissociation between CLPP and microtubules may participate in the intracellular transport of cholesterol to the plasma membrane.
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28
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Abstract
Most types of cells in the body do not express the capability of catabolizing cholesterol, so cholesterol efflux is essential for homeostasis. For instance, macrophages possess four pathways for exporting free (unesterified) cholesterol to extracellular high density lipoprotein (HDL). The passive processes include simple diffusion via the aqueous phase and facilitated diffusion mediated by scavenger receptor class B, type 1 (SR-BI). Active pathways are mediated by the ATP-binding cassette (ABC) transporters ABCA1 and ABCG1, which are membrane lipid translocases. The efflux of cellular phospholipid and free cholesterol to apolipoprotein A-I promoted by ABCA1 is essential for HDL biogenesis. Current understanding of the molecular mechanisms involved in these four efflux pathways is presented in this minireview.
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Affiliation(s)
- Michael C Phillips
- From the Division of Translational Medicine and Human Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-5158
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Tortelli B, Fujiwara H, Bagel JH, Zhang J, Sidhu R, Jiang X, Yanjanin NM, Shankar RK, Carillo-Carasco N, Heiss J, Ottinger E, Porter FD, Schaffer JE, Vite CH, Ory DS. Cholesterol homeostatic responses provide biomarkers for monitoring treatment for the neurodegenerative disease Niemann-Pick C1 (NPC1). Hum Mol Genet 2014; 23:6022-33. [PMID: 24964810 DOI: 10.1093/hmg/ddu331] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Niemann-Pick C1 (NPC1) disease is a rare, neurodegenerative lysosomal cholesterol storage disorder, typified by progressive cognitive and motor function impairment. Affected individuals usually succumb to the disease in adolescence. 2-Hydroxypropyl-β-cyclodextrin (HP-β-CD) has emerged as a promising intervention that reduces lipid storage and prolongs survival in NPC1 disease animal models. A barrier to the development of HP-β-CD and other treatments for NPC disease has been the lack of validated biochemical measures to evaluate efficacy. Here we explored whether cholesterol homeostatic responses resulting from HP-β-CD-mediated redistribution of sequestered lysosomal cholesterol could provide biomarkers to monitor treatment. Upon direct CNS delivery of HP-β-CD, we found increases in plasma 24(S)-HC in two independent NPC1 disease animal models, findings that were confirmed in human NPC1 subjects receiving HP-β-CD. Since circulating 24(S)-HC is almost exclusively CNS-derived, the increase in plasma 24(S)-HC provides a peripheral, non-invasive measure of the CNS effect of HP-β-CD. Our findings suggest that plasma 24(S)-HC, along with the other cholesterol-derived markers examined in this study, can serve as biomarkers that will accelerate development of therapeutics for NPC1 disease.
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Affiliation(s)
- Brett Tortelli
- Diabetic Cardiovascular Disease Center and Department of Medicine, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Hideji Fujiwara
- Diabetic Cardiovascular Disease Center and Department of Medicine, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Jessica H Bagel
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jessie Zhang
- Diabetic Cardiovascular Disease Center and Department of Medicine, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Rohini Sidhu
- Diabetic Cardiovascular Disease Center and Department of Medicine, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Xuntian Jiang
- Diabetic Cardiovascular Disease Center and Department of Medicine, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Nicole M Yanjanin
- Department of Health and Human Services, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development
| | - Roopa Kanakatti Shankar
- Department of Health and Human Services, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development
| | - Nuria Carillo-Carasco
- Department of Health and Human Services, Surgical Neurology Branch, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, USA and
| | - John Heiss
- Department of Health and Human Services, Surgical Neurology Branch, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, USA and
| | - Elizabeth Ottinger
- Therapeutics for Rare and Neglected Diseases (TRND) Program, National Center for Advancing Translational Sciences (NCATS), Bethesda, MD, USA
| | - Forbes D Porter
- Department of Health and Human Services, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development
| | - Jean E Schaffer
- Diabetic Cardiovascular Disease Center and Department of Medicine, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Charles H Vite
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Daniel S Ory
- Diabetic Cardiovascular Disease Center and Department of Medicine, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA,
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30
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Li G, Gu HM, Zhang DW. ATP-binding cassette transporters and cholesterol translocation. IUBMB Life 2014; 65:505-12. [PMID: 23983199 DOI: 10.1002/iub.1165] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 02/22/2013] [Indexed: 01/26/2023]
Abstract
Cholesterol, a major component of mammalian cell membranes, plays important structural and functional roles. However, accumulation of excessive cholesterol is toxic to cells. Aberrant cholesterol trafficking and accumulation is the molecular basis for many diseases, such as atherosclerotic cardiovascular disease and Tangier's disease. Accumulation of excessive cholesterol is also believed to contribute to the early onset of Alzheimer's disease. Thus, cellular cholesterol homeostasis is tightly regulated by uptake, de novo synthesis, and efflux. Any surplus of cholesterol must either be stored in the cytosol in the form of esters or released from the cell. Recently, several ATP-binding cassette (ABC) transporters, such as ABCA1, ABCG1, ABCG5, and ABCG8 have been shown to play important roles in the regulation of cellular cholesterol homeostasis by mediating cholesterol efflux. Mutations in ABC transporters are associated with several human diseases. In this review, we discuss the physiological roles of ABC transporters and the underlying mechanisms by which they mediate cholesterol translocation.
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Affiliation(s)
- Ge Li
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
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31
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Yu XH, Jiang N, Yao PB, Zheng XL, Cayabyab FS, Tang CK. NPC1, intracellular cholesterol trafficking and atherosclerosis. Clin Chim Acta 2014; 429:69-75. [DOI: 10.1016/j.cca.2013.11.026] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 11/17/2013] [Accepted: 11/23/2013] [Indexed: 11/30/2022]
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Tsunemi A, Ueno T, Fukuda N, Watanabe T, Tahira K, Haketa A, Hatanaka Y, Tanaka S, Matsumoto T, Matsumoto Y, Nagase H, Soma M. A novel gene regulator, pyrrole-imidazole polyamide targeting ABCA1 gene increases cholesterol efflux from macrophages and plasma HDL concentration. J Mol Med (Berl) 2014; 92:509-21. [PMID: 24463557 DOI: 10.1007/s00109-013-1118-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 11/29/2013] [Accepted: 12/16/2013] [Indexed: 01/08/2023]
Abstract
UNLABELLED Pyrrole-imidazole (PI) polyamides are nuclease-resistant novel compounds that inhibit transcription factors by binding to the minor groove of DNA. A PI polyamide that targets mouse ABCA1 and increases ABCA1 gene expression was designed and evaluated as an agent to increase plasma HDL concentration. A PI polyamide was designed to bind the activator protein-2 binding site of the mouse ABCA1 promoter. The effect of this PI polyamide on ABCA1 expression was evaluated by real-time RT-PCR and Western blotting using RAW264 cells. In vivo effects of this polyamide on ABCA1 gene expression and plasma HDL level were examined in C57B6 mice. One milligram per kilogram of body weight of PI polyamide was injected via the tail veins every 2 days for 1 week, and plasma lipid profiles were evaluated. PI polyamide showed a specific binding to the target DNA in gel mobility shift assay. Treatment of RAW264 cells with 1.0 μM PI polyamide significantly increased ABCA1 mRNA expression. PI polyamide also significantly increased apolipoprotein AI-mediated HDL biogenesis in RAW264 cells. Cellular cholesterol efflux mediated by apolipoprotein AI was significantly increased by the PI polyamide treatment. PI polyamide significantly increased expression of ABCA1 mRNA in the liver of C57B6 mice. Plasma HDL concentration was increased by PI polyamide administration. All of the HDL sub-fractions showed a tendency to increase after PI polyamide administration. The designed PI polyamide that targeted ABCA1 successfully increased ABCA1 expression and HDL biogenesis. This novel gene-regulating agent is promising as a useful compound to increase plasma HDL concentration. KEY MESSAGES A novel pyrrole-imidazole (PI) polyamide binds to ABCA1. PI polyamide interfered with binding of AP-2ɑ protein to the ABCA1 gene promoter. PI polyamide inhibited the AP-2ɑ-mediated reduction of ABCA1 gene and protein expression. PI polyamide increased ABCA1 protein and apolipoprotein AI mediated HDL biogenesis. PI polyamide is a new gene regulator for the prevention of atherosclerotic diseases.
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Affiliation(s)
- Akiko Tsunemi
- Department of Medicine, Division of Nephrology, Hypertension and Endocrinology, Nihon University School of Medicine, 30-1 Oyaguchi-kami, Itabashi, Tokyo, Japan
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Westerterp M, Bochem AE, Yvan-Charvet L, Murphy AJ, Wang N, Tall AR. ATP-Binding Cassette Transporters, Atherosclerosis, and Inflammation. Circ Res 2014; 114:157-70. [DOI: 10.1161/circresaha.114.300738] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Marit Westerterp
- From the Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY (M.W., A.E.B., L.Y.-C., A.J.M., N.W., A.R.T.); Departments of Medical Biochemistry (M.W.) and Vascular Medicine (A.E.B.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and Haematopoiesis and Leukocyte Biology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (A.J.M.)
| | - Andrea E. Bochem
- From the Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY (M.W., A.E.B., L.Y.-C., A.J.M., N.W., A.R.T.); Departments of Medical Biochemistry (M.W.) and Vascular Medicine (A.E.B.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and Haematopoiesis and Leukocyte Biology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (A.J.M.)
| | - Laurent Yvan-Charvet
- From the Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY (M.W., A.E.B., L.Y.-C., A.J.M., N.W., A.R.T.); Departments of Medical Biochemistry (M.W.) and Vascular Medicine (A.E.B.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and Haematopoiesis and Leukocyte Biology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (A.J.M.)
| | - Andrew J. Murphy
- From the Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY (M.W., A.E.B., L.Y.-C., A.J.M., N.W., A.R.T.); Departments of Medical Biochemistry (M.W.) and Vascular Medicine (A.E.B.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and Haematopoiesis and Leukocyte Biology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (A.J.M.)
| | - Nan Wang
- From the Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY (M.W., A.E.B., L.Y.-C., A.J.M., N.W., A.R.T.); Departments of Medical Biochemistry (M.W.) and Vascular Medicine (A.E.B.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and Haematopoiesis and Leukocyte Biology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (A.J.M.)
| | - Alan R. Tall
- From the Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY (M.W., A.E.B., L.Y.-C., A.J.M., N.W., A.R.T.); Departments of Medical Biochemistry (M.W.) and Vascular Medicine (A.E.B.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and Haematopoiesis and Leukocyte Biology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (A.J.M.)
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Abstract
PURPOSE OF REVIEW Mutations in lysosomal acid lipase A (LIPA) result in two phenotypes depending on the extent of lysosomal acid lipase (LAL) deficiency: the severe, early-onset Wolman disease or the less severe cholesteryl ester storage disease (CESD). In CESD, the severity of the symptoms, hepatomegaly and hypercholesterolaemia, can be highly variable, presenting in childhood or adulthood. Therefore, it is likely that many patients are undiagnosed or misdiagnosed. Nevertheless, LAL deficiency has been recognized for more than 25 years, but adequate therapeutic strategies are limited. RECENT FINDINGS CESD has an estimated prevalence of one in 90,000 to 170,000 individuals in the general population, confirming the likelihood that this disease is currently underdiagnosed. A number of studies have shown that in LIPA deficient patients the hypercholesterolaemic phenotype can be attenuated using statin therapy, and favourable effects on reduction of lipid accumulation in lysosomes have been reported. Targeting lysosomal exocytosis with LAL replacement therapy was shown to be successful in animal models and recently a phase I/II study demonstrated its safety and its potential metabolic efficacy on transaminase levels. SUMMARY The hypercholesterolaemic phenotype in CESD can be difficult to distinguish from other known hypercholesterolaemic disorders. In the majority of CESD cases with hypercholesterolaemia favourable responses on statin treatment are observed, but the effect on reduction of lipid accumulation in lysosomes needs to be further evaluated. Combining statins with LAL replacement therapy may provide a promising approach for optimal treatment of LIPA deficiencies in the future.
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Affiliation(s)
- Sigrid W Fouchier
- Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands.
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35
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Li G, Gu HM, Zhang DW. ATP-binding cassette transporters and cholesterol translocation. IUBMB Life 2013:n/a-n/a. [PMID: 23625363 DOI: 10.1002/iub.01165] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 02/22/2013] [Indexed: 11/08/2022]
Abstract
Cholesterol, a major component of mammalian cell membranes, plays important structural and functional roles. However, accumulation of excessive cholesterol is toxic to cells. Aberrant cholesterol trafficking and accumulation is the molecular basis for many diseases, such as atherosclerotic cardiovascular disease and Tangier's disease. Accumulation of excessive cholesterol is also believed to contribute to the early onset of Alzheimer's disease. Thus, cellular cholesterol homeostasis is tightly regulated by uptake, de novo synthesis, and efflux. Any surplus of cholesterol must either be stored in the cytosol in the form of esters or released from the cell. Recently, several ATP-binding cassette (ABC) transporters, such as ABCA1, ABCG1, ABCG5, and ABCG8 have been shown to play important roles in the regulation of cellular cholesterol homeostasis by mediating cholesterol efflux. Mutations in ABC transporters are associated with several human diseases. In this review, we discuss the physiological roles of ABC transporters and the underlying mechanisms by which they mediate cholesterol translocation. © 2013 IUBMB Life, 2013.
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Affiliation(s)
- Ge Li
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, AB, Canada
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36
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Okoro EU, Zhao Y, Guo Z, Zhou L, Lin X, Yang H. Apolipoprotein E4 is deficient in inducing macrophage ABCA1 expression and stimulating the Sp1 signaling pathway. PLoS One 2012; 7:e44430. [PMID: 22984509 PMCID: PMC3439389 DOI: 10.1371/journal.pone.0044430] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 08/02/2012] [Indexed: 11/18/2022] Open
Abstract
ATP binding cassette A1 (ABCA1) is a membrane protein that promotes cellular cholesterol efflux. Using RAW 264.7 macrophages, we studied the relative effects of apolipoprotein (apo) E3 and apoE4 on ABCA1 and on the signaling pathway that regulates its expression. Both lipid-associated and lipid-free apoE4 forms induced ∼30% lower levels of ABCA1 protein and mRNA than apoE3 forms. Phosphorylated levels of phosphoinositol 3-kinase (PI3K), protein kinase Cζ (PKCζ) and specificity protein 1 (Sp1) were also lower when treated with apoE4 compared to apoE3. The reduced ability of apoE4 to induce ABCA1 expression, PKCζ and Sp1 phosphorylation were confirmed in human THP-1 monocytes/macrophages. Sequential phosphorylation of PI3K, PKCζ and Sp1 has been suggested as a mechanism for upregulation of ABCA1 expression. Both apoE3 and apoE4 reduced total cholesterol and cholesterol esters in lipid-laden RAW 264.7 cells, and induced apoAI-mediated cholesterol efflux. However, the cholesterol esters and cholesterol efflux in apoE4-treated cells were ∼50% and ∼24% lower, respectively, compared to apoE3-treated cells. Accumulation of cholesterol esters in macrophages is a mechanism for foam cell formation. Thus the reduced ability of apoE4 to activate the PI3K-PKCζ-Sp1 signaling pathway and induce ABCA1 expression likely impairs cholesterol ester removal, and increases foam cell formation.
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Affiliation(s)
- Emmanuel Ugochukwu Okoro
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - Yanfeng Zhao
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - ZhongMao Guo
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - Lichun Zhou
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - Xinghua Lin
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - Hong Yang
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
- * E-mail:
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Arciello A, De Marco N, Del Giudice R, Guglielmi F, Pucci P, Relini A, Monti DM, Piccoli R. Insights into the fate of the N-terminal amyloidogenic polypeptide of ApoA-I in cultured target cells. J Cell Mol Med 2012; 15:2652-63. [PMID: 21306558 PMCID: PMC4373434 DOI: 10.1111/j.1582-4934.2011.01271.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Apolipoprotein A-I (ApoA-I) is an extracellular lipid acceptor, whose role in cholesterol efflux and high-density lipoprotein formation is mediated by ATP-binding cassette transporter A1 (ABCA1). Nevertheless, some ApoA-I variants are associated to systemic forms of amyloidosis, characterized by extracellular fibril deposition in peripheral organs. Heart amyloid fibrils were found to be mainly constituted by the 93-residue N-terminal fragment of ApoA-I, named [1-93]ApoA-I. In this paper, rat cardiomyoblasts were used as target cells to analyse binding, internalization and intracellular fate of the fibrillogenic polypeptide in comparison to full-length ApoA-I. We provide evidence that the polypeptide: (i) binds to specific sites on cell membrane (K(d) = 5.90 ± 0.70 × 10(-7) M), where it partially co-localizes with ABCA1, as also described for ApoA-I; (ii) is internalized mostly by chlatrin-mediated endocytosis and lipid rafts, whereas ApoA-I is internalized preferentially by chlatrin-coated pits and macropinocytosis and (iii) is rapidly degraded by proteasome and lysosomes, whereas ApoA-I partially co-localizes with recycling endosomes. Vice versa, amyloid fibrils, obtained by in vitro aggregation of [1-93]ApoA-I, were found to be unable to enter the cells. We propose that internalization and intracellular degradation of [1-93]ApoA-I may divert the polypeptide from amyloid fibril formation and contribute to the slow progression and late onset that characterize this pathology.
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Affiliation(s)
- Angela Arciello
- Department of Structural and Functional Biology, University of Naples Federico II, School of Biotechnological Sciences, Naples, Italy
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Ouimet M, Marcel YL. Regulation of Lipid Droplet Cholesterol Efflux From Macrophage Foam Cells. Arterioscler Thromb Vasc Biol 2012; 32:575-81. [DOI: 10.1161/atvbaha.111.240705] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cholesterol efflux from macrophages is the first and potentially most important step in reverse cholesterol transport, a process especially relevant to atherosclerosis and to the regression of atherosclerotic plaques. Increasingly, lipid droplet (LD) cholesteryl ester (CE) hydrolysis is being recognized as a rate-limiting step in cholesterol efflux. The traditional view on macrophage CE hydrolysis is that this pathway is entirely dependent on the action of neutral hydrolases, and numerous candidate CE hydrolases have been proposed to play a role in lipid hydrolysis in macrophages and atherogenesis. Although the exact identity of macrophage-specific CE hydrolases remains to be clarified, a common point to all of these studies is that enhancing LD-associated CE hydrolysis increases cholesterol efflux and is antiatherogenic. Understanding how cholesterol is mobilized from LDs offers new steps for modulating cholesterol efflux, and recently a role for autophagy and lysosomal acid lipase in macrophage lipolysis has emerged. Autophagy and lysosomal acid lipase thus represent novel therapeutic targets to enhance macrophage reverse cholesterol transport. This review discusses our current understanding of the relationship between macrophage LDs and atherosclerosis and presents recent insights into the mechanisms for LD CE hydrolysis in macrophage foam cells.
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Affiliation(s)
- Mireille Ouimet
- From the Department of Biochemistry, Microbiology, and Immunology (M.O., Y.L.M.), Department of Pathology and Laboratory Medicine (Y.L.M.), University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Yves L. Marcel
- From the Department of Biochemistry, Microbiology, and Immunology (M.O., Y.L.M.), Department of Pathology and Laboratory Medicine (Y.L.M.), University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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Yu X, Li X, Zhao G, Xiao J, Mo Z, Yin K, Jiang Z, Fu Y, Zha X, Tang C. OxLDL up-regulates Niemann-Pick type C1 expression through ERK1/2/COX-2/PPARα-signaling pathway in macrophages. Acta Biochim Biophys Sin (Shanghai) 2012; 44:119-28. [PMID: 22232299 DOI: 10.1093/abbs/gmr119] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Niemann-Pick type C1 (NPC1) is located mainly in the membranes of the late endosome/lysosome and controls the intracellular cholesterol trafficking from the late endosome/lysosome to the plasma membrane. It has been reported that oxidized low-density lipoprotein (oxLDL) can up-regulate NPC1 expression. However, the detailed mechanisms are not fully understood. In this study, we investigated the effect of oxLDL stimulation on NPC1 expression in THP-1 macrophages. Our results showed that oxLDL up-regulated NPC1 expression at both mRNA and protein levels in a dose-dependent and time-dependent manner. In addition, oxLDL also induced the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2). Treatment with oxLDL significantly increased cyclooxygenase-2 (COX-2) mRNA and protein expression in the macrophages, and these increases were suppressed by the ERK1/2 inhibitor PD98059 or ERK1/2 small interfering RNA (siRNA) treatment. OxLDL up-regulated the expression of peroxisome proliferator-activated receptor α (PPARα) at the mRNA and protein levels, which could be abolished by COX-2 siRNA or COX-2 inhibitor NS398 treatment in these macrophages. OxLDL dramatically elevated cellular cholesterol efflux, which was abrogated by inhibiting ERK1/2 and/or COX-2. In addition, oxLDL-induced NPC1 expression and cellular cholesterol efflux were reversed by PPARα siRNA or GW6471, an antagonist of PPARα. Taken together, these results provide the evidence that oxLDL can up-regulate the expression of the NPC1 through ERK1/2/COX-2/PPARα-signaling pathway in macrophages.
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Affiliation(s)
- Xiaohua Yu
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Life Science Research Center, University of South China, Hengyang, China
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40
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Chen X, Guo Z, Okoro EU, Zhang H, Zhou L, Lin X, Rollins AT, Yang H. Up-regulation of ATP binding cassette transporter A1 expression by very low density lipoprotein receptor and apolipoprotein E receptor 2. J Biol Chem 2011; 287:3751-9. [PMID: 22170052 DOI: 10.1074/jbc.m111.310888] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of very low density lipoprotein receptor (VLDLR) and apolipoprotein E receptor 2 (apoER2) results in either pro- or anti-atherogenic effects depending on the ligand. Using reelin and apoE as ligands, we studied the impact of VLDLR- and apoER2-mediated signaling on the expression of ATP binding cassette transporter A1 (ABCA1) and cholesterol efflux using RAW264.7 cells. Treatment of these mouse macrophages with reelin or human apoE3 significantly increased ABCA1 mRNA and protein levels, and apoAI-mediated cholesterol efflux. In addition, both reelin and apoE3 significantly increased phosphorylated disabled-1 (Dab1), phosphatidylinositol 3-kinase (PI3K), protein kinase Cζ (PKCζ), and specificity protein 1 (Sp1). This reelin- or apoER2-mediated up-regulation of ABCA1 expression was suppressed by 1) knockdown of Dab1, VLDLR, and apoER2 with small interfering RNAs (siRNAs), 2) inhibition of PI3K and PKC with kinase inhibitors, 3) overexpression of kinase-dead PKCζ, and 4) inhibition of Sp1 DNA binding with mithramycin A. Activation of the Dab1-PI3K signaling pathway has been implicated in VLDLR- and apoER2-mediated cellular functions, whereas the PI3K-PKCζ-Sp1 signaling cascade has been implicated in the regulation of ABCA1 expression induced by apoE/apoB-carrying lipoproteins. Taken together, these data support a model in which activation of VLDLR and apoER2 by reelin and apoE induces ABCA1 expression and cholesterol efflux via a Dab1-PI3K-PKCζ-Sp1 signaling cascade.
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Affiliation(s)
- Xinping Chen
- Department of Physiology, Meharry Medical College, Nashville, Tennessee 37208, USA
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41
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Boadu E, Nelson RC, Francis GA. ABCA1-dependent mobilization of lysosomal cholesterol requires functional Niemann-Pick C2 but not Niemann-Pick C1 protein. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:396-404. [PMID: 22179027 DOI: 10.1016/j.bbalip.2011.11.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 10/28/2011] [Accepted: 11/28/2011] [Indexed: 10/14/2022]
Abstract
Niemann-Pick disease type C (NPC) is caused by mutations leading to loss of function of NPC1 or NPC2 proteins, resulting in accumulation of unesterified cholesterol in late endosomes and lysosomes. We previously reported that expression of the ATP-binding cassette transporter A1 (ABCA1) is impaired in human NPC1(-/-) fibroblasts, resulting in reduced HDL particle formation and providing a mechanism for the reduced plasma HDL cholesterol seen in the majority of NPC1 patients. We also found that treatment of NPC1(-/-) fibroblasts with an agonist of liver X-receptor corrects ABCA1 expression and HDL formation and reduces lysosomal cholesterol accumulation. We have confirmed that ABCA1 expression is also reduced in NPC2(-/-) cells, and found that α-HDL particle formation is impaired in these cells. To determine whether selective up-regulation of ABCA1 can correct lysosomal cholesterol accumulation in NPC disease cells and HDL particle formation, we produced and infected NPC1(-/-) and NPC2(-/-) fibroblasts with an adenovirus expressing full-length ABCA1 and enhanced green fluorescent protein (AdABCA1-EGFP). ABCA1-EGFP expression in NPC1(-/-) fibroblasts resulted in normalization of cholesterol efflux to apolipoprotein A-I (apoA-I) and α-HDL particle formation, plus a marked reduction in filipin staining of unesterified cholesterol in late endosomes/lysosomes. In contrast, AdABCA1-EGFP treatment of NPC2(-/-) fibroblasts to normalize ABCA1 expression had no effect on cholesterol efflux to apoA-I or accumulation of excess cholesterol in lysosomes, and only partially corrected α-HDL formation by these cells. These results suggest that correction of ABCA1 expression can bypass the mutation of NPC1 but not NPC2 to mobilize excess cholesterol from late endosomes and lysosomes in NPC disease cells. Expression of ABCA1-EGFP in NPC1(-/-) cells increased cholesterol available for esterification and reduced levels of HMG-CoA reductase protein, effects that were abrogated by co-incubation with apoA-I. A model can be generated in which ABCA1 is able to mobilize cholesterol, to join the intracellular regulatory pool or to be effluxed for HDL particle formation, either directly or indirectly from the lysosomal membrane, but not from the lysosomal lumen. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).
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Affiliation(s)
- Emmanuel Boadu
- Department of Medicine and UBC James Hogg Research Centre, Providence Heart and Lung Institute, University of British Columbia, Vancouver, Canada
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Sankaranarayanan S, Kellner-Weibel G, de la Llera-Moya M, Phillips MC, Asztalos BF, Bittman R, Rothblat GH. A sensitive assay for ABCA1-mediated cholesterol efflux using BODIPY-cholesterol. J Lipid Res 2011; 52:2332-2340. [PMID: 21957199 DOI: 10.1194/jlr.d018051] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Studies have shown a negative association between cellular cholesterol efflux and coronary artery disease (CAD). Standard protocol for quantitating cholesterol efflux involves labeling cells with [(3)H]cholesterol and measuring release of the labeled sterol. Using [(3)H]cholesterol is not ideal for the development of a high-throughput assay to screen large numbers of serum as would be required in studying the link between efflux and CAD. We compared efflux using a fluorescent sterol (boron dipyrromethene difluoride linked to sterol carbon-24, BODIPY-cholesterol) with that of [(3)H]cholesterol in J774 macrophages. Fractional efflux of BODIPY-cholesterol was significantly higher than that of [(3)H]cholesterol when apo A-I, HDL(3), or 2% apoB-depleted human serum were used as acceptors. BODIPY-cholesterol efflux correlated significantly with [(3)H]cholesterol efflux (p < 0.0001) when apoB-depleted sera were used. The BODIPY-cholesterol efflux correlated significantly with preβ-1 (r(2) = 0.6) but not with total HDL-cholesterol. Reproducibility of the BODIPY-cholesterol efflux assay was excellent between weeks (r(2) = 0.98, inter-assay CV = 3.31%). These studies demonstrate that BODIPY-cholesterol provides an efficient measurement of efflux compared with [(3)H]cholesterol and is a sensitive probe for ABCA1-mediated efflux. The increased sensitivity of BODIPY-cholesterol assay coupled with the simplicity of measuring fluorescence results in a sensitive, high-throughput assay that can screen large numbers of sera, and thus establish the relationship between cholesterol efflux and atherosclerosis.
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Affiliation(s)
- Sandhya Sankaranarayanan
- Department of Pediatrics (Division of Gastroenterology, Hepatology, and Nutrition), The Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | - Ginny Kellner-Weibel
- Department of Pediatrics (Division of Gastroenterology, Hepatology, and Nutrition), The Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | - Margarita de la Llera-Moya
- Department of Pediatrics (Division of Gastroenterology, Hepatology, and Nutrition), The Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | - Michael C Phillips
- Department of Pediatrics (Division of Gastroenterology, Hepatology, and Nutrition), The Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | - Bela F Asztalos
- Lipid Metabolism Laboratory (B.F.A.), Tufts University, Boston, MA 02111; and Department of Chemistry and Biochemistry (R.B)
| | - Robert Bittman
- Department of Chemistry and Biochemistry (R.B), Queens College of The City University of New York, Flushing, NY 11367-1597
| | - George H Rothblat
- Department of Pediatrics (Division of Gastroenterology, Hepatology, and Nutrition), The Children's Hospital of Philadelphia, Philadelphia, PA 19104.
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Bowden KL, Bilbey NJ, Bilawchuk LM, Boadu E, Sidhu R, Ory DS, Du H, Chan T, Francis GA. Lysosomal acid lipase deficiency impairs regulation of ABCA1 gene and formation of high density lipoproteins in cholesteryl ester storage disease. J Biol Chem 2011; 286:30624-30635. [PMID: 21757691 PMCID: PMC3162423 DOI: 10.1074/jbc.m111.274381] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Indexed: 11/06/2022] Open
Abstract
ATP-binding cassette transporter A1 (ABCA1) mediates the rate-limiting step in high density lipoprotein (HDL) particle formation, and its expression is regulated primarily by oxysterol-dependent activation of liver X receptors. We previously reported that ABCA1 expression and HDL formation are impaired in the lysosomal cholesterol storage disorder Niemann-Pick disease type C1 and that plasma HDL-C is low in the majority of Niemann-Pick disease type C patients. Here, we show that ABCA1 regulation and activity are also impaired in cholesteryl ester storage disease (CESD), caused by mutations in the LIPA gene that result in less than 5% of normal lysosomal acid lipase (LAL) activity. Fibroblasts from patients with CESD showed impaired up-regulation of ABCA1 in response to low density lipoprotein (LDL) loading, reduced phospholipid and cholesterol efflux to apolipoprotein A-I, and reduced α-HDL particle formation. Treatment of normal fibroblasts with chloroquine to inhibit LAL activity reduced ABCA1 expression and activity, similar to that of CESD cells. Liver X receptor agonist treatment of CESD cells corrected ABCA1 expression but failed to correct LDL cholesteryl ester hydrolysis and cholesterol efflux to apoA-I. LDL-induced production of 27-hydroxycholesterol was reduced in CESD compared with normal fibroblasts. Treatment with conditioned medium containing LAL from normal fibroblasts or with recombinant human LAL rescued ABCA1 expression, apoA-I-mediated cholesterol efflux, HDL particle formation, and production of 27-hydroxycholesterol by CESD cells. These results provide further evidence that the rate of release of cholesterol from late endosomes/lysosomes is a critical regulator of ABCA1 expression and activity, and an explanation for the hypoalphalipoproteinemia seen in CESD patients.
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Affiliation(s)
- Kristin L Bowden
- Department of Medicine, Institute for Heart and Lung Health, St. Paul's Hospital, Vancouver, British Columbia V6Z 1Y6, Canada
| | - Nicolas J Bilbey
- Department of Medicine, Institute for Heart and Lung Health, St. Paul's Hospital, Vancouver, British Columbia V6Z 1Y6, Canada
| | - Leanne M Bilawchuk
- Department of Medicine, Institute for Heart and Lung Health, St. Paul's Hospital, Vancouver, British Columbia V6Z 1Y6, Canada
| | - Emmanuel Boadu
- Department of Medicine, Institute for Heart and Lung Health, St. Paul's Hospital, Vancouver, British Columbia V6Z 1Y6, Canada
| | - Rohini Sidhu
- Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Daniel S Ory
- Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Hong Du
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229
| | - Teddy Chan
- Department of Medicine, Institute for Heart and Lung Health, St. Paul's Hospital, Vancouver, British Columbia V6Z 1Y6, Canada
| | - Gordon A Francis
- Department of Medicine, Institute for Heart and Lung Health, St. Paul's Hospital, Vancouver, British Columbia V6Z 1Y6, Canada.
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44
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Le Lay S, Rodriguez M, Jessup W, Rentero C, Li Q, Cartland S, Grewal T, Gaus K. Caveolin-1-mediated apolipoprotein A-I membrane binding sites are not required for cholesterol efflux. PLoS One 2011; 6:e23353. [PMID: 21858084 PMCID: PMC3155548 DOI: 10.1371/journal.pone.0023353] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 07/13/2011] [Indexed: 11/18/2022] Open
Abstract
Caveolin-1 (Cav1), a structural protein required for the formation of invaginated membrane domains known as caveolae, has been implicated in cholesterol trafficking and homeostasis. Here we investigated the contribution of Cav1 to apolipoprotein A-I (apoA-I) cell surface binding and intracellular processing using mouse embryonic fibroblasts (MEFs) derived from wild type (WT) or Cav1-deficient (Cav1(-/-)) animals. We found that cells expressing Cav1 have 2.6-fold more apoA-I binding sites than Cav1(-/-) cells although these additional binding sites are not associated with detergent-free lipid rafts. Further, Cav1-mediated binding targets apoA-I for internalization and degradation and these processes are not correlated to cholesterol efflux. Despite lower apoA-I binding, cholesterol efflux from Cav1(-/-) MEFs is 1.7-fold higher than from WT MEFs. Stimulation of ABCA1 expression with an LXR agonist enhances cholesterol efflux from both WT and Cav1(-/-) cells without increasing apoA-I surface binding or affecting apoA-I processing. Our results indicate that there are at least two independent lipid binding sites for apoA-I; Cav1-mediated apoA-I surface binding and uptake is not linked to cholesterol efflux, indicating that membrane domains other than caveolae regulate ABCA1-mediated cholesterol efflux.
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Affiliation(s)
- Soazig Le Lay
- Centre de Recherche des Cordeliers, INSERM, U872, Paris, France
| | - Macarena Rodriguez
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Wendy Jessup
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Carles Rentero
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Qiong Li
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Siân Cartland
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, Australia
| | - Katharina Gaus
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
- * E-mail:
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45
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Vihervaara T, Uronen RL, Wohlfahrt G, Björkhem I, Ikonen E, Olkkonen VM. Sterol binding by OSBP-related protein 1L regulates late endosome motility and function. Cell Mol Life Sci 2011; 68:537-51. [PMID: 20690035 PMCID: PMC11114714 DOI: 10.1007/s00018-010-0470-z] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 06/24/2010] [Accepted: 07/14/2010] [Indexed: 11/26/2022]
Abstract
ORP1L is an oxysterol binding homologue that regulates late endosome (LE) positioning. We show that ORP1L binds several oxysterols and cholesterol, and characterize a mutant, ORP1L Δ560-563, defective in oxysterol binding. While wild-type ORP1L clusters LE, ORP1L Δ560-563 induces LE scattering, which is reversed by disruption of the endoplasmic reticulum (ER) targeting FFAT motif, suggesting that it is due to enhanced LE-ER interactions. Endosome motility is reduced upon overexpression of ORP1L. Both wild-type ORP1L and the Δ560-563 mutant induce the recruitment of both dynactin and kinesin-2 on LE. Most of the LE decorated by overexpressed ORP1L fail to accept endocytosed dextran or EGF, and the transfected cells display defective degradation of internalized EGF. ORP1L silencing in macrophage foam cells enhances endosome motility and results in inhibition of [(3)H]cholesterol efflux to apolipoprotein A-I. These data demonstrate that LE motility and functions in both protein and lipid transport are regulated by ORP1L.
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Affiliation(s)
- Terhi Vihervaara
- Minerva Foundation Institute for Medical Research, Biomedicum Helsinki 2U, Tukholmankatu 8, 00290 Helsinki, Finland
- National Institute for Health and Welfare/Public Health Genomics Unit, Biomedicum 1, 00290 Helsinki, Finland
| | - Riikka-Liisa Uronen
- Institute of Biomedicine/Anatomy, University of Helsinki, P.O. Box 63, 00014 Helsinki, Finland
| | - Gerd Wohlfahrt
- Computer-Aided Drug Design, Orion Pharma, Orionintie 1, 02101 Espoo, Finland
| | - Ingemar Björkhem
- Karolinska Institutet, Karolinska University Hospital Huddinge, 14186 Stockholm, Sweden
| | - Elina Ikonen
- Institute of Biomedicine/Anatomy, University of Helsinki, P.O. Box 63, 00014 Helsinki, Finland
| | - Vesa M. Olkkonen
- Minerva Foundation Institute for Medical Research, Biomedicum Helsinki 2U, Tukholmankatu 8, 00290 Helsinki, Finland
- National Institute for Health and Welfare/Public Health Genomics Unit, Biomedicum 1, 00290 Helsinki, Finland
- Institute of Biomedicine/Anatomy, University of Helsinki, P.O. Box 63, 00014 Helsinki, Finland
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Chen X, Zhao Y, Guo Z, Zhou L, Okoro EU, Yang H. Transcriptional regulation of ATP-binding cassette transporter A1 expression by a novel signaling pathway. J Biol Chem 2011; 286:8917-23. [PMID: 21257755 DOI: 10.1074/jbc.m110.214429] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
ATP-binding cassette transporter A1 (ABCA1) is a membrane-bound protein that regulates the efflux of cholesterol derived from internalized lipoproteins. Using a mouse macrophage cell line, this report studied the impact of low-density lipoproteins (LDL) on ABCA1 expression and the signaling pathway responsible for lipoprotein-induced ABCA1 expression. Our data demonstrated that treatment of macrophages with LDL increased ABCA1 mRNA and protein levels 4.3- and 3.5-fold, respectively. LDL also induced an ∼2-fold increase in macrophage surface expression of ABCA1 and a 14-fold-increase in apolipoprotein AI-mediated cholesterol efflux. In addition, LDL significantly increased the level of phosphorylated specificity protein 1 (Sp1) and the amount of Sp1 bound to the ABCA1 promoter without alteration in total Sp1 protein level. Mutation of the Sp1 binding site in the ABCA1 promoter and inhibition of Sp1 DNA binding with mithramycin A suppressed the ABCA1 promoter activity and reduced the ABCA1 expression level induced by LDL. LDL treatment also elevated protein kinase C-ζ (PKC-ζ) phosphorylation and induced PKC-ζ binding with Sp1. Inhibition of PKC-ζ with kinase inhibitors or overexpression of kinase-dead PKC-ζ attenuated Sp1 phosphorylation and ABCA1 expression induced by LDL. These results demonstrate for the first time that activation of the PKCζ-Sp1 signaling cascade is a mechanism for regulation of LDL-induced ABCA1 expression.
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Affiliation(s)
- Xinping Chen
- Department of Physiology, Meharry Medical College, Nashville, Tennessee 37208, USA
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47
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The β-subunit of ATP synthase is involved in cellular uptake and resecretion of apoA-I but does not control apoA-I-induced lipid efflux in adipocytes. Mol Cell Biochem 2010; 348:155-64. [PMID: 21069432 DOI: 10.1007/s11010-010-0650-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 10/28/2010] [Indexed: 10/18/2022]
Abstract
Cellular uptake and resecretion of apoA-I (apoA-I recycling) could be an important factor in determining the circulating plasma levels of apoA-I and/or HDL. Using a novel method to study protein recycling, we have recently demonstrated recycling of apoA-I by adipocytes and suggested that this is a receptor mediated process independent of ABCA1 function. In the present study, it is shown that apoA-I recycling by adipocytes can be blocked by a monoclonal antibody against the β-subunit of ATP synthase, a protein that had been previously identified as an apoA-I receptor. Investigation of the cellular recycling of two other proteins, an apolipoprotein and a small globular protein, showed that recycling of apoA-I is a selective process. The present study also shows that blocking apoA-I recycling has no effect on the rate of apoA-I-induced cholesterol or phospholipid efflux. It is concluded that cellular recycling of apoA-I is a selective process that involves the ectopically expressed β-subunit of ATP synthase. The physiological function of apoA-I recycling remains to be elucidated. However, this study shows that the process of apoA-I uptake and resecretion is not required for apoA-I lipidation.
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48
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Ma W, Xu J, Wang Q, Xin Y, Zhang L, Zheng X, Wang H, Sun K, Hui R, Huang X. Interaction of functional NPC1 gene polymorphism with smoking on coronary heart disease. BMC MEDICAL GENETICS 2010; 11:149. [PMID: 20955564 PMCID: PMC2966454 DOI: 10.1186/1471-2350-11-149] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 10/18/2010] [Indexed: 11/22/2022]
Abstract
Background The protein of Niemann-pick type C1 gene (NPC1) is known to facilitate the egress of cholesterol and other lipids from late endosomes and lysosomes to other cellular compartments. This study aims to investigate whether the genetic variation in NPC1 is associated with risk of coronary heart disease (CHD) and to detect whether NPC1 might interact with smoking on the risk of CHD. Methods We performed a case-control study, including 873 patients with coronary heart disease (CHD) and 864 subjects without CHD as control. Polymorphisms of NPC1 gene were genotyped by polymerase chain reaction (PCR) -restriction fragment length polymorphism (RFLP). Results A tag-SNP rs1805081 (+644A > G) in NPC1 was identified. The G allele of the +644 locus showed reduced risk of CHD than wild-type genotype in Chinese population (recessive model GG vs. AG+AA: odds ratio [OR] 0.647, 95% CI 0.428 to 0.980, P = 0.039; additive model GG vs. AG vs. AA: OR 0.847, 95% CI 0.718 to 0.998, P = 0.0471). Moreover in smokers, the G-allele carriers had reduced risk of CHD compared with A-allele carries (OR 0.552, 95% CI 0.311 to 0.979, P = 0.0421). Conclusions The results of the present study suggest that NPC1 variants seem to be contributors to coronary heart disease occurrence in Chinese population. Moreover, in smokers, NPC1 variants seem to confer protection to coronary heart disease.
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Affiliation(s)
- Weiwei Ma
- Department of Cardiology, and Sino-German Laboratory for Molecular Medicine, FuWai Hospital and Cardiovascular Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishilu, 100037 Beijing, China
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49
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Schweitzer JK, Sedgwick AE, D'Souza-Schorey C. ARF6-mediated endocytic recycling impacts cell movement, cell division and lipid homeostasis. Semin Cell Dev Biol 2010; 22:39-47. [PMID: 20837153 DOI: 10.1016/j.semcdb.2010.09.002] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 08/31/2010] [Accepted: 09/03/2010] [Indexed: 01/19/2023]
Abstract
A wide range of cellular activities depends upon endocytic recycling. ARF6, a small molecular weight GTPase, regulates the processes of endocytosis and endocytic recycling in concert with various effector molecules and other small GTPases. This review highlights three critical processes that involve ARF6-mediated endosomal membrane trafficking-cell motility, cytokinesis, and cholesterol homeostasis. In each case, the function of ARF6-mediated trafficking varies-including localization of specific protein and lipid cargo, regulation of bulk membrane movement, and modulation of intracellular signaling. As described in this review, mis-regulation of endocytic traffic can result in human disease when it compromises the cell's ability to regulate cell movement and invasion, cell division, and lipid homeostasis.
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Affiliation(s)
- Jill Kuglin Schweitzer
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556-0369, USA
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50
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Terasaka N, Westerterp M, Koetsveld J, Fernández-Hernando C, Yvan-Charvet L, Wang N, Sessa WC, Tall AR. ATP-binding cassette transporter G1 and high-density lipoprotein promote endothelial NO synthesis through a decrease in the interaction of caveolin-1 and endothelial NO synthase. Arterioscler Thromb Vasc Biol 2010; 30:2219-25. [PMID: 20798376 DOI: 10.1161/atvbaha.110.213215] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To investigate whether cholesterol efflux to high-density lipoprotein (HDL) via ATP-binding cassette transporter G1 (ABCG1) modulates the interaction of caveolin (Cav) 1 and endothelial NO synthase (eNOS). METHODS AND RESULTS ABCG1 promotes cholesterol and 7-oxysterol efflux from endothelial cells (ECs) to HDL. It was previously reported that ABCG1 protects against dietary cholesterol-induced endothelial dysfunction by promoting the efflux of 7-oxysterols to HDL. Increased cholesterol loading in ECs is known to cause an inhibitory interaction between Cav-1 and eNOS and impaired NO release. In human aortic ECs, free cholesterol loading promoted the interaction of Cav-1 with eNOS, reducing eNOS activity. These effects of cholesterol loading were reversed by HDL in an ABCG1-dependent manner. HDL also reversed the inhibition of eNOS by cholesterol loading in murine lung ECs, but this effect of HDL was abolished in Cav-1-deficient murine lung ECs. Increased interaction of Cav-1 with eNOS was also detected in aortic homogenates of high-cholesterol diet-fed Abcg1(-/-) mice, paralleling a decrease in eNOS activity and impaired endothelial function. CONCLUSIONS The promotion of cholesterol efflux via ABCG1 results in a reduced inhibitory interaction of eNOS with Cav-1.
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Affiliation(s)
- Naoki Terasaka
- Division of Molecular Medicine, Department of Medicine, Columbia University, 630 W 168 St, New York, NY 10032, USA
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