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Mahmoudi A, Atkin SL, Jamialahmadi T, Sahebkar A. Identification of key upregulated genes involved in foam cell formation and the modulatory role of statin therapy. Int Immunopharmacol 2023; 119:110209. [PMID: 37130442 DOI: 10.1016/j.intimp.2023.110209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/14/2023] [Accepted: 04/15/2023] [Indexed: 05/04/2023]
Abstract
BACKGROUND We aimed to investigate the possible effect of statins on important genes/proteins involved in foam cell formation. METHODS The gene expression profile of the GSE9874, GSE54666, and GSE7138from the Omnibus database were usedto identify genes involved in foam cell formation. The protein-protein interaction (PPI) network and MCODE analysis of the intersection of three databases were analyzed. We used molecular docking analysis to investigate the possible interaction of different statins with the overexpressed hub genes obtained from PPI analysis. RESULTS The intersection among the three datasets showed 54 upregulated and 26 down-regulated genes. The most critical overexpressed genes/proteins obtained as hub genes included: G6PD, NPC1, ABCA1, ABCG1, PGD, PLIN2, PPAP2B, and TXNRD1 based on PPI analysis. Functional enrichment analysis of 81 intersection DEGs at the biological process level focusing on the cholesterol metabolic process, secondary alcohol biosynthetic process and the cholesterol biosynthetic process. Under cellular components, the analysis confirmed that these 81 intersection DEGs were mainly applied in endoplasmic reticulum membrane, lysosome and lytic vacuole. The molecular functions were identified as sterol binding, oxidoreductase activity and NADP binding. The molecular docking showed that all statins appear to affect important protein targets overexpressed in foam cell formation. However, lipophilic statins, especially pitavastatin and lovastatin, had a greater effect than hydrophilic statins. The most significant protein target of all the overexpressed genes interacting with all statin types was ABCA1. CONCLUSION The effect of lipophilic statins was shown for several critical proteins in foam cell formation.
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Affiliation(s)
- Ali Mahmoudi
- Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Medical Biotechnology and Nanotechnology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad 9177899191, Iran
| | - Stephen L Atkin
- School of Postgraduate Studies and Research, RCSI Medical University of Bahrain, Busaiteen 15503, Bahrain
| | - Tannaz Jamialahmadi
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amirhossein Sahebkar
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; School of Medicine, The University of Western Australia, Perth, Australia; Department of Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
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2
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Morin EE, Guo Y, He H, Yuan W, Souery WN, Fawaz MV, Chen YE, Schwendeman A. Synergetic Effect of rHDL and LXR Agonist on Reduction of Atherosclerosis in Mice. Front Pharmacol 2021; 11:513031. [PMID: 33390931 PMCID: PMC7772318 DOI: 10.3389/fphar.2020.513031] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 10/19/2020] [Indexed: 12/12/2022] Open
Abstract
High-density lipoproteins (HDLs) are unique in that they play an important role in the reverse cholesterol transport process. However, reconstituted HDL (rHDL) infusions have demonstrated limited beneficial effect in clinical practice. This is perhaps a consequence of the limited cholesterol efflux abilities of atheroma macrophages due to decreased expression of cholesterol transporters in advanced atheromas and following rHDL infusion treatment. Thus, we propose that a combination therapy of rHDL and a liver X receptor (LXR) agonist could maximize the therapeutic benefit of rHDL by upregulating ATP-binding cassette transporters A-1 (ABCA1) and ATP-binding cassette transporter G-1 (ABCG1), and enhancing cholesterol efflux to rHDL. In macrophages, rHDL downregulated the expression of ABCA1/G1 in a dose- and rHDL composition-dependent manner. Although LXR agonist, T0901317 (T1317), upregulated the expression of ABCA1 and ABCG1, the drug itself did not have any effect on cholesterol efflux (6.6 ± 0.5%) while the combination of rHDL and T1317 exhibited enhanced cholesterol efflux from [3H]-cholesterol loaded J774A.1 macrophages (23.3 ± 1.3%). Treatment with rHDL + T1317 significantly reduced the area of aortic plaque in ApoE-/- mice compared to PBS treated control animals (24.16 ± 1.42% vs. 31.59 ± 1.93%, p < 0.001), while neither rHDL nor T1317 treatment alone had a significant effect. Together, we show that rHDL paired with an LXR agonist can induce a synergetic effect in reducing atheroma burden. This synergy could lead to lower overall effective dose for both drugs, potentially overcoming the existing barriers in clinical development and renewing pharmaceutical interest in these two drug classes.
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Affiliation(s)
- Emily E Morin
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, MI, United States
| | - Yanhong Guo
- Department of Internal Medicine, University of Michigan, NCRC, Ann Arbor, MI, United States
| | - Hongliang He
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, MI, United States
| | - Wenmin Yuan
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, MI, United States
| | - Whitney N Souery
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, MI, United States
| | - Maria V Fawaz
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, United States
| | - Yuqing Eugene Chen
- Department of Internal Medicine, University of Michigan, NCRC, Ann Arbor, MI, United States
| | - Anna Schwendeman
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, MI, United States.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States
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3
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Zhou ZS, Li MX, Liu J, Jiao H, Xia JM, Shi XJ, Zhao H, Chu L, Liu J, Qi W, Luo J, Song BL. Competitive oxidation and ubiquitylation on the evolutionarily conserved cysteine confer tissue-specific stabilization of Insig-2. Nat Commun 2020; 11:379. [PMID: 31953408 PMCID: PMC6969111 DOI: 10.1038/s41467-019-14231-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 12/19/2019] [Indexed: 11/09/2022] Open
Abstract
Insig-2 is an ER membrane protein negatively controlling lipid biosynthesis. Here, we find that Insig-2 is increased in the tissues, including liver, but unaltered in the muscle of gp78-deficient mice. In hepatocytes and undifferentiated C2C12 myoblasts, Insig-2 is ubiquitylated on Cys215 by gp78 and degraded. However, the C215 residue is oxidized by elevated reactive oxygen species (ROS) during C2C12 myoblasts differentiating into myotubes, preventing Insig-2 from ubiquitylation and degradation. The stabilized Insig-2 downregulates lipogenesis through inhibiting the SREBP pathway, helping to channel the carbon flux to ATP generation and protecting myotubes from lipid over-accumulation. Evolutionary analysis shows that the YECK (in which C represents Cys215 in human Insig-2) tetrapeptide sequence in Insig-2 is highly conserved in amniotes but not in aquatic amphibians and fishes, suggesting it may have been shaped by differential selection. Together, this study suggests that competitive oxidation-ubiquitylation on Cys215 of Insig-2 senses ROS and prevents muscle cells from lipid accumulation.
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Affiliation(s)
- Zhang-Sen Zhou
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Mei-Xin Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Jie Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Hengwu Jiao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Jing-Ming Xia
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Xiong-Jie Shi
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Huabin Zhao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Liping Chu
- School of Life Science and Technology, ShanghaiTech Universiy, Shanghai, 201203, China
| | - Jingrong Liu
- School of Life Science and Technology, ShanghaiTech Universiy, Shanghai, 201203, China
| | - Wei Qi
- School of Life Science and Technology, ShanghaiTech Universiy, Shanghai, 201203, China
| | - Jie Luo
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Bao-Liang Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
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Lifsey HC, Kaur R, Thompson BH, Bennett L, Temel RE, Graf GA. Stigmasterol stimulates transintestinal cholesterol excretion independent of liver X receptor activation in the small intestine. J Nutr Biochem 2019; 76:108263. [PMID: 31759199 DOI: 10.1016/j.jnutbio.2019.108263] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 10/14/2019] [Accepted: 10/29/2019] [Indexed: 02/09/2023]
Abstract
Despite advances in healthcare, cardiovascular disease (CVD) remains the leading cause of death in the United States. Elevated levels of plasma cholesterol are highly predictive of CVD and stroke and are the principal driver of atherosclerosis. Unfortunately, current cholesterol lowering agents, such as statins, are not known to reverse atherosclerotic disease once it has been established. In preclinical models, agonists of nuclear receptor, LXR, have been shown to reduce and reverse atherosclerosis. Phytosterols are bioactive non-cholesterol sterols that act as LXR agonists and regulate cholesterol metabolism and transport. We hypothesized that stigmasterol would act as an LXR agonist and alter intestinal cholesterol secretion to promote cholesterol elimination. Mice were fed a control diet, or a diet supplemented with stigmasterol (0.3% w/w) or T0901317 (0.015% w/w), a known LXR agonist. In this experiment we analyzed the sterol content of bile, intestinal perfusate, plasma, and feces. Additionally, the liver and small intestine were analyzed for relative levels of transcripts known to be regulated by LXR. We observed that T0901317 robustly promoted cholesterol elimination and acted as a strong LXR agonist. Stigmasterol promoted transintestinal cholesterol secretion through an LXR-independent pathway.
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Affiliation(s)
| | - Rupinder Kaur
- Department of Pharmaceutical Sciences, College of Pharmacy
| | | | - Lisa Bennett
- Department of Pharmaceutical Sciences, College of Pharmacy
| | - Ryan E Temel
- Department of Physiology, College of Medicine, University of Kentucky; Saha Cardiovascular Research Center
| | - Gregory A Graf
- Department of Pharmaceutical Sciences, College of Pharmacy; Saha Cardiovascular Research Center; Barnstable Brown Diabetes and Obesity Center.
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5
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Jin P, Bian Y, Wang K, Cong G, Yan R, Sha Y, Ma X, Zhou J, Yuan Z, Jia S. Homocysteine accelerates atherosclerosis via inhibiting LXRα-mediated ABCA1/ABCG1-dependent cholesterol efflux from macrophages. Life Sci 2018; 214:41-50. [PMID: 30393020 DOI: 10.1016/j.lfs.2018.10.060] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 10/15/2018] [Accepted: 10/26/2018] [Indexed: 11/19/2022]
Abstract
AIMS Macrophage-derived foam-cell formation plays a crucial role in the development of atherosclerosis, and liver X receptor alpha (LXRα) is a key regulator of lipid metabolism in macrophages. Homocysteine (Hcy) is an independent risk factor of atherosclerosis; however, the regulation of lipid metabolism and role of LXRα induced by Hcy in macrophages is still unknown. The present study aimed to investigate the potential role of Hcy in disordered lipid metabolism and atherosclerotic lesions, especially the effects of Hcy on cholesterol efflux in macrophages and the possible mechanisms. MAIN METHODS In vitro, lipid accumulation and cholesterol efflux were evaluated in THP-1 macrophages with Hcy intervention. Real-time quantitative PCR and western blot analyses were used to assess mRNA and protein levels. In vivo, atherosclerotic lesions and lipid profiles were evaluated by methionine diet-induced hyperhomocysteinemia (HHcy) in ApoE-/- mice. The LXRα agonist T0901317 was used to verify the role of LXRα in HHcy-accelerated atherosclerosis. KEY FINDINGS Hcy promoted lipid accumulation and inhibited cholesterol efflux in THP-1 macrophages. HHcy mice showed increased lesion area and lipid accumulation in plaque. Both studies in vitro and in vivo showed decreased expression of ATP binding cassette transporter A1 (ABCA1) and G1 (ABCG1). T0901317 treatment increased ABCA1 and ABCG1 levels; reversed macrophage-derived foam-cell formation in THP-1 macrophages and reduced atherosclerotic lesions in ApoE-/- mice. SIGNIFICANCE Inhibition of LXRα-mediated ABCA1/ABCG1-dependent cholesterol efflux from macrophages is a novel mechanism in Hcy-accelerated atherosclerosis.
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Affiliation(s)
- Ping Jin
- Department of Clinical Medicine, Ningxia Medical University, Yinchuan, Ningxia 750001, China
| | - Yitong Bian
- Department of Radiology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
| | - Kai Wang
- Heart Center, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750001, China
| | - Guangzhi Cong
- Heart Center, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750001, China
| | - Ru Yan
- Institute of Cardiovascular Diseases, General Hospital of Ningxia Medical University Yinchuan, Ningxia 750001, China
| | - Yong Sha
- Heart Center, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750001, China
| | - Xueping Ma
- Heart Center, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750001, China
| | - Juan Zhou
- Department of Cardiovascular Medicine, The First Affiliated Hospital of the Medical School, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
| | - Zuyi Yuan
- Department of Cardiovascular Medicine, The First Affiliated Hospital of the Medical School, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
| | - Shaobin Jia
- Heart Center, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750001, China; Institute of Cardiovascular Diseases, General Hospital of Ningxia Medical University Yinchuan, Ningxia 750001, China.
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6
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Dysfunctional HDL in diabetes mellitus and its role in the pathogenesis of cardiovascular disease. Mol Cell Biochem 2017; 440:167-187. [PMID: 28828539 DOI: 10.1007/s11010-017-3165-z] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/16/2017] [Indexed: 12/17/2022]
Abstract
Coronary artery disease, the leading cause of death in the developed and developing countries, is prevalent in diabetes mellitus with 68% cardiovascular disease (CVD)-related mortality. Epidemiological studies suggested inverse correlation between HDL and CVD occurrence. Therefore, low HDL concentration observed in diabetic patients compared to non-diabetic individuals was thought to be one of the primary causes of increased risks of CVD. Efforts to raise HDL level via CETP inhibitors, Torcetrapib and Dalcetrapib, turned out to be disappointing in outcome studies despite substantial increases in HDL-C, suggesting that factors beyond HDL concentration may be responsible for the increased risks of CVD. Therefore, recent studies have focused more on HDL function than on HDL levels. The metabolic environment in diabetes mellitus condition such as hyperglycemia-induced advanced glycation end products, oxidative stress, and inflammation promote HDL dysfunction leading to greater risks of CVD. This review discusses dysfunctional HDL as one of the mechanisms of increased CVD risks in diabetes mellitus through adversely affecting components that support HDL function in cholesterol efflux and LDL oxidation. The dampening of reverse cholesterol transport, a key process that removes cholesterol from lipid-laden macrophages in the arterial wall, leads to increased risks of CVD in diabetic patients. Therapeutic approaches to keep diabetes under control may benefit patients from developing CVD.
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7
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Zhang X, Heckmann BL, Campbell LE, Liu J. G0S2: A small giant controller of lipolysis and adipose-liver fatty acid flux. Biochim Biophys Acta Mol Cell Biol Lipids 2017. [PMID: 28645852 DOI: 10.1016/j.bbalip.2017.06.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The discovery of adipose triglyceride lipase (ATGL) and its coactivator comparative gene identification-58 (CGI-58) provided a major paradigm shift in the understanding of intracellular lipolysis in both adipocytes and nonadipocyte cells. The subsequent discovery of G0/G1 switch gene 2 (G0S2) as a potent endogenous inhibitor of ATGL revealed a unique mechanism governing lipolysis and fatty acid (FA) availability. G0S2 is highly conserved in vertebrates, and exhibits cyclical expression pattern between adipose tissue and liver that is critical to lipid flux and energy homeostasis in these two tissues. Biochemical and cell biological studies have demonstrated that a direct interaction with ATGL mediates G0S2's inhibitory effects on lipolysis and lipid droplet degradation. In this review we examine evidence obtained from recent in vitro and in vivo studies that lends support to the proof-of-principle concept that G0S2 functions as a master regulator of tissue-specific balance of TG storage vs. mobilization, partitioning of metabolic fuels between adipose and liver, and the whole-body adaptive energy response. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
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Affiliation(s)
- Xiaodong Zhang
- Department of Biochemistry & Molecular Biology, Mayo Clinic College of Medicine, Scottsdale, AZ, United States; HEAL(th) Program, Mayo Clinic, Scottsdale, AZ, United States
| | - Bradlee L Heckmann
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, United States
| | - Latoya E Campbell
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Jun Liu
- Department of Biochemistry & Molecular Biology, Mayo Clinic College of Medicine, Scottsdale, AZ, United States; HEAL(th) Program, Mayo Clinic, Scottsdale, AZ, United States; Division of Endocrinology, Mayo Clinic, Scottsdale, AZ, United States.
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8
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Heckmann BL, Zhang X, Saarinen AM, Schoiswohl G, Kershaw EE, Zechner R, Liu J. Liver X receptor α mediates hepatic triglyceride accumulation through upregulation of G0/G1 Switch Gene 2 expression. JCI Insight 2017; 2:e88735. [PMID: 28239648 DOI: 10.1172/jci.insight.88735] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Liver X receptors (LXRs) are transcription factors essential for cholesterol homeostasis and lipogenesis. LXRα has been implicated in regulating hepatic triglyceride (TG) accumulation upon both influx of adipose-derived fatty acids (FAs) during fasting and stimulation of de novo FA synthesis by chemical agonism of LXR. However, whether or not a convergent mechanism is employed to drive deposition of FAs from these 2 different sources in TGs is undetermined. Here, we report that the G0/G1 Switch Gene 2 (G0S2), a selective inhibitor of intracellular TG hydrolysis/lipolysis, is a direct target gene of LXRα. Transcriptional activation is conferred by LXRα binding to a direct repeat 4 (DR4) motif in the G0S2 promoter. While LXRα-/- mice exhibited decreased hepatic G0S2 expression, adenoviral expression of G0S2 was sufficient to restore fasting-induced TG storage and glycogen depletion in the liver of these mice. In response to LXR agonist T0901317, G0S2 ablation prevented hepatic steatosis and hypertriglyceridemia without affecting the beneficial effects on HDL. Thus, the LXRα-G0S2 axis plays a distinct role in regulating hepatic TG during both fasting and pharmacological activation of LXR.
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Affiliation(s)
- Bradlee L Heckmann
- Department of Biochemistry and Molecular Biology.,HEALth Program, Mayo Clinic in Arizona, Scottsdale, Arizona, USA.,Mayo Graduate School, Rochester, Minnesota, USA
| | - Xiaodong Zhang
- Department of Biochemistry and Molecular Biology.,HEALth Program, Mayo Clinic in Arizona, Scottsdale, Arizona, USA
| | - Alicia M Saarinen
- Department of Biochemistry and Molecular Biology.,HEALth Program, Mayo Clinic in Arizona, Scottsdale, Arizona, USA
| | - Gabriele Schoiswohl
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Erin E Kershaw
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Jun Liu
- Department of Biochemistry and Molecular Biology.,HEALth Program, Mayo Clinic in Arizona, Scottsdale, Arizona, USA.,Division of Endocrinology, Mayo Clinic in Arizona, Scottsdale, Arizona, USA
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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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10
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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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11
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Inflammation, lipid metabolism dysfunction, and hypertension: Active research fields in atherosclerosis-related cardiovascular disease in China. SCIENCE CHINA-LIFE SCIENCES 2011; 54:976-9. [DOI: 10.1007/s11427-011-4225-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Accepted: 09/07/2011] [Indexed: 11/25/2022]
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12
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Calkin AC, Tontonoz P. Liver x receptor signaling pathways and atherosclerosis. Arterioscler Thromb Vasc Biol 2010; 30:1513-8. [PMID: 20631351 DOI: 10.1161/atvbaha.109.191197] [Citation(s) in RCA: 222] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
First discovered as orphan receptors, liver X receptors (LXRs) were subsequently identified as the nuclear receptor target of the cholesterol metabolites, oxysterols. There are 2 LXR receptors encoded by distinct genes: LXRalpha is most highly expressed in the liver, adipose, kidney, adrenal tissues, and macrophages and LXRbeta is ubiquitously expressed. Despite differential tissue distribution, these isoforms have 78% homology in their ligand-binding domain and appear to respond to the same endogenous ligands. Work over the past 10 years has shown that the LXR pathway regulates lipid metabolism and inflammation via both the induction and repression of target genes. Given the importance of cholesterol regulation and inflammation in the development of cardiovascular disease, it is not surprising that activation of the LXR pathway attenuates various mechanisms underlying atherosclerotic plaque development. In this brief review, we will discuss the impact of the LXR pathway on both cholesterol metabolism and atherosclerosis.
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Affiliation(s)
- Anna C Calkin
- Howard Hughes Medical Institute, University of California at Los Angeles, School of Medicine, Box 951662, Los Angeles, CA 90095-1662, USA
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13
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Li X, Yeh V, Molteni V. Liver X receptor modulators: a review of recently patented compounds (2007 - 2009). Expert Opin Ther Pat 2010; 20:535-62. [PMID: 20302451 DOI: 10.1517/13543771003621269] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
IMPORTANCE OF THE FIELD Liver X receptors (LXRs) are ligand activated transcription factors involved in cholesterol metabolism, glucose homeostasis, inflammation and lipogenesis. With the important physiological role of LXRs in reverse cholesterol transport (RCT), atherosclerosis is the best investigated therapeutic indication. While atherosclerosis is not yet clinically validated, Wyeth's LXRalpha/beta agonist LXR-623 indicated the key LXR target genes involved in RCT (ABCA1 and ABCG1) are upregulated in peripheral blood cells in a dose-dependent manner. While discontinued for CNS safety concerns, investigation of LXR-623 supports atherosclerosis as a clinical indication, and the possibility of identifying LXR agonists with profiles that avoid the strong lipogenic effects of full LXRalpha/beta agonists. AREAS COVERED IN THIS REVIEW Patents for LXR agonists from late 2006 up to August 2009 with emphasis on chemical matters and relationship to earlier disclosures, the biological data associated with selected analogues and therapeutic indications. WHAT THE READER WILL GAIN An overview of the majority of LXR scaffolds with representative structure activity relationships as well as the companies that are the chief players in the field. TAKE HOME MESSAGE The future application of LXR agonists depends upon the discovery of LXR agents without lipogenic effects. Limiting activation of LXRalpha is a popular strategy.
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Affiliation(s)
- Xiaolin Li
- Genomics Institute of the Novartis Research Foundation, Department of Medicinal Chemistry, San Diego, CA 92121, USA
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14
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Hu YW, Zheng L, Wang Q. Regulation of cholesterol homeostasis by liver X receptors. Clin Chim Acta 2010; 411:617-25. [PMID: 20060389 DOI: 10.1016/j.cca.2009.12.027] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2009] [Revised: 12/21/2009] [Accepted: 12/21/2009] [Indexed: 12/13/2022]
Abstract
Cellular cholesterol levels reflect a balance between uptake, efflux, and endogenous synthesis. The sterol-responsive transcription factors liver X receptors (LXRalpha and LXRbeta) help maintain cholesterol homeostasis, not only through promotion of cholesterol efflux from peripheral tissues but also through suppression of de novo synthesis and exogenous cholesterol uptake. In this review, we summarize the important role of LXRs in regulating expression of key members that keep cholesterol levels in balance.
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Affiliation(s)
- Yan-Wei Hu
- Laboratory Medicine Center, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, China
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Ma X, Hu YW, Mo ZC, Li XX, Liu XH, Xiao J, Yin WD, Liao DF, Tang CK. NO-1886 Up-regulates Niemann–Pick C1 Protein (NPC1) Expression Through Liver X Receptor α Signaling Pathway in THP-1 Macrophage-Derived Foam Cells. Cardiovasc Drugs Ther 2009; 23:199-206. [DOI: 10.1007/s10557-009-6165-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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