1
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He Z, Zhang Z, Xu P, Dirsch VM, Wang L, Wang K. Laminarin Reduces Cholesterol Uptake and NPC1L1 Protein Expression in High-Fat Diet (HFD)-Fed Mice. Mar Drugs 2023; 21:624. [PMID: 38132943 PMCID: PMC10744832 DOI: 10.3390/md21120624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 11/27/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023] Open
Abstract
Aberrantly high dietary cholesterol intake and intestinal cholesterol uptake lead to dyslipidemia, one of the risk factors for cardiovascular diseases (CVDs). Based on previous studies, laminarin, a polysaccharide found in brown algae, has hypolipidemic activity, but its underlying mechanism has not been elucidated. In this study, we investigated the effect of laminarin on intestinal cholesterol uptake in vitro, as well as the lipid and morphological parameters in an in vivo model of high-fat diet (HFD)-fed mice, and addressed the question of whether Niemann-Pick C1-like 1 protein (NPC1L1), a key transporter mediating dietary cholesterol uptake, is involved in the mechanistic action of laminarin. In in vitro studies, BODIPY-cholesterol-labeled Caco-2 cells were examined using confocal microscopy and a fluorescence reader. The results demonstrated that laminarin inhibited cholesterol uptake into Caco-2 cells in a concentration-dependent manner (EC50 = 20.69 μM). In HFD-fed C57BL/6J mice, laminarin significantly reduced the serum levels of total cholesterol (TC), total triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C). It also decreased hepatic levels of TC, TG, and total bile acids (TBA) while promoting the excretion of fecal cholesterol. Furthermore, laminarin significantly reduced local villous damage in the jejunum of HFD mice. Mechanistic studies revealed that laminarin significantly downregulated NPC1L1 protein expression in the jejunum of HFD-fed mice. The siRNA-mediated knockdown of NPC1L1 attenuated the laminarin-mediated inhibition of cholesterol uptake in Caco-2 cells. This study suggests that laminarin significantly improves dyslipidemia in HFD-fed mice, likely by reducing cholesterol uptake through a mechanism that involves the downregulation of NPC1L1 expression.
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Affiliation(s)
- Zhuoqian He
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao 266073, China; (Z.H.); (P.X.); (K.W.)
| | - Zhongyin Zhang
- Department of Medicinal Chemistry, School of Pharmacy, Qingdao University Medical College, Qingdao 266073, China;
| | - Pengfei Xu
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao 266073, China; (Z.H.); (P.X.); (K.W.)
| | - Verena M. Dirsch
- Department of Pharmaceutical Sciences, Faculty of Life Sciences, University of Vienna, 1090 Vienna, Austria;
| | - Limei Wang
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao 266073, China; (Z.H.); (P.X.); (K.W.)
- Institute of Innovative Drugs, Qingdao University, Qingdao 266071, China
| | - Kewei Wang
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao 266073, China; (Z.H.); (P.X.); (K.W.)
- Institute of Innovative Drugs, Qingdao University, Qingdao 266071, China
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2
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Abstract
The cholesterol efflux protein ATP binding cassette protein A1 (ABCA) and apolipoprotein A1 (apo A1) are key constituents in the process of reverse-cholesterol transport (RCT), whereby excess cholesterol in the periphery is transported to the liver where it can be converted primarily to bile acids for either use in digestion or excreted. Due to their essential roles in RCT, numerous studies have been conducted in cells, mice, and humans to more thoroughly understand the pathways that regulate their expression and activity with the goal of developing therapeutics that enhance RCT to reduce the risk of cardiovascular disease. Many of the drugs and natural compounds examined target several transcription factors critical for ABCA1 expression in both macrophages and the liver. Likewise, several miRNAs target not only ABCA1 but also the same transcription factors that are critical for its high expression. However, after years of research and many preclinical and clinical trials, only a few leads have proven beneficial in this regard. In this review we discuss the various transcription factors that serve as drug targets for ABCA1 and provide an update on some important leads.
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3
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Frambach SJ, de Haas R, Smeitink JA, Russel FG, Schirris TJ. Restoring cellular NAD(P)H levels by PPARα and LXRα stimulation to improve mitochondrial complex I deficiency. Life Sci 2022; 300:120571. [DOI: 10.1016/j.lfs.2022.120571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 04/08/2022] [Accepted: 04/18/2022] [Indexed: 10/18/2022]
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4
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Mota AC, Dominguez M, Weigert A, Snodgrass RG, Namgaladze D, Brüne B. Lysosome-Dependent LXR and PPARδ Activation Upon Efferocytosis in Human Macrophages. Front Immunol 2021; 12:637778. [PMID: 34025647 PMCID: PMC8137840 DOI: 10.3389/fimmu.2021.637778] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 04/23/2021] [Indexed: 01/01/2023] Open
Abstract
Efferocytosis is critical for tissue homeostasis, as its deregulation is associated with several autoimmune pathologies. While engulfing apoptotic cells, phagocytes activate transcription factors, such as peroxisome proliferator-activated receptors (PPAR) or liver X receptors (LXR) that orchestrate metabolic, phagocytic, and inflammatory responses towards the ingested material. Coordination of these transcription factors in efferocytotic human macrophages is not fully understood. In this study, we evaluated the transcriptional profile of macrophages following the uptake of apoptotic Jurkat T cells using RNA-seq analysis. Results indicated upregulation of PPAR and LXR pathways but downregulation of sterol regulatory element-binding proteins (SREBP) target genes. Pharmacological inhibition and RNA interference pointed to LXR and PPARδ as relevant transcriptional regulators, while PPARγ did not substantially contribute to gene regulation. Mechanistically, lysosomal digestion and lysosomal acid lipase (LIPA) were required for PPAR and LXR activation, while PPARδ activation also demanded an active lysosomal phospholipase A2 (PLA2G15). Pharmacological interference with LXR signaling attenuated ABCA1-dependent cholesterol efflux from efferocytotic macrophages, but suppression of inflammatory responses following efferocytosis occurred independently of LXR and PPARδ. These data provide mechanistic details on LXR and PPARδ activation in efferocytotic human macrophages.
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Affiliation(s)
- Ana Carolina Mota
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, Frankfurt, Germany
| | - Monica Dominguez
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, Frankfurt, Germany
| | - Andreas Weigert
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, Frankfurt, Germany
| | - Ryan G Snodgrass
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, Frankfurt, Germany
| | - Dmitry Namgaladze
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, Frankfurt, Germany
| | - Bernhard Brüne
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, Frankfurt, Germany.,Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Frankfurt, Germany.,German Cancer Consortium (DKTK), Partner Site Frankfurt, Frankfurt, Germany.,Frankfurt Cancer Institute, Goethe-University Frankfurt, Frankfurt, Germany
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5
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Frambach SJCM, de Haas R, Smeitink JAM, Rongen GA, Russel FGM, Schirris TJJ. Brothers in Arms: ABCA1- and ABCG1-Mediated Cholesterol Efflux as Promising Targets in Cardiovascular Disease Treatment. Pharmacol Rev 2020; 72:152-190. [PMID: 31831519 DOI: 10.1124/pr.119.017897] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Atherosclerosis is a leading cause of cardiovascular disease worldwide, and hypercholesterolemia is a major risk factor. Preventive treatments mainly focus on the effective reduction of low-density lipoprotein cholesterol, but their therapeutic value is limited by the inability to completely normalize atherosclerotic risk, probably due to the disease complexity and multifactorial pathogenesis. Consequently, high-density lipoprotein cholesterol gained much interest, as it appeared to be cardioprotective due to its major role in reverse cholesterol transport (RCT). RCT facilitates removal of cholesterol from peripheral tissues, including atherosclerotic plaques, and its subsequent hepatic clearance into bile. Therefore, RCT is expected to limit plaque formation and progression. Cellular cholesterol efflux is initiated and propagated by the ATP-binding cassette (ABC) transporters ABCA1 and ABCG1. Their expression and function are expected to be rate-limiting for cholesterol efflux, which makes them interesting targets to stimulate RCT and lower atherosclerotic risk. This systematic review discusses the molecular mechanisms relevant for RCT and ABCA1 and ABCG1 function, followed by a critical overview of potential pharmacological strategies with small molecules to enhance cellular cholesterol efflux and RCT. These strategies include regulation of ABCA1 and ABCG1 expression, degradation, and mRNA stability. Various small molecules have been demonstrated to increase RCT, but the underlying mechanisms are often not completely understood and are rather unspecific, potentially causing adverse effects. Better understanding of these mechanisms could enable the development of safer drugs to increase RCT and provide more insight into its relation with atherosclerotic risk. SIGNIFICANCE STATEMENT: Hypercholesterolemia is an important risk factor of atherosclerosis, which is a leading pathological mechanism underlying cardiovascular disease. Cholesterol is removed from atherosclerotic plaques and subsequently cleared by the liver into bile. This transport is mediated by high-density lipoprotein particles, to which cholesterol is transferred via ATP-binding cassette transporters ABCA1 and ABCG1. Small-molecule pharmacological strategies stimulating these transporters may provide promising options for cardiovascular disease treatment.
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Affiliation(s)
- Sanne J C M Frambach
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences (S.J.C.M.F., G.A.R., F.G.M.R., T.J.J.S.), Radboud Center for Mitochondrial Medicine (S.J.C.M.F., R.d.H., J.A.M.S., F.G.M.R., T.J.J.S.), Department of Pediatrics (R.d.H., J.A.M.S.), and Department of Internal Medicine, Radboud Institute for Health Sciences (G.A.R.), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ria de Haas
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences (S.J.C.M.F., G.A.R., F.G.M.R., T.J.J.S.), Radboud Center for Mitochondrial Medicine (S.J.C.M.F., R.d.H., J.A.M.S., F.G.M.R., T.J.J.S.), Department of Pediatrics (R.d.H., J.A.M.S.), and Department of Internal Medicine, Radboud Institute for Health Sciences (G.A.R.), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jan A M Smeitink
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences (S.J.C.M.F., G.A.R., F.G.M.R., T.J.J.S.), Radboud Center for Mitochondrial Medicine (S.J.C.M.F., R.d.H., J.A.M.S., F.G.M.R., T.J.J.S.), Department of Pediatrics (R.d.H., J.A.M.S.), and Department of Internal Medicine, Radboud Institute for Health Sciences (G.A.R.), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Gerard A Rongen
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences (S.J.C.M.F., G.A.R., F.G.M.R., T.J.J.S.), Radboud Center for Mitochondrial Medicine (S.J.C.M.F., R.d.H., J.A.M.S., F.G.M.R., T.J.J.S.), Department of Pediatrics (R.d.H., J.A.M.S.), and Department of Internal Medicine, Radboud Institute for Health Sciences (G.A.R.), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Frans G M Russel
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences (S.J.C.M.F., G.A.R., F.G.M.R., T.J.J.S.), Radboud Center for Mitochondrial Medicine (S.J.C.M.F., R.d.H., J.A.M.S., F.G.M.R., T.J.J.S.), Department of Pediatrics (R.d.H., J.A.M.S.), and Department of Internal Medicine, Radboud Institute for Health Sciences (G.A.R.), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Tom J J Schirris
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences (S.J.C.M.F., G.A.R., F.G.M.R., T.J.J.S.), Radboud Center for Mitochondrial Medicine (S.J.C.M.F., R.d.H., J.A.M.S., F.G.M.R., T.J.J.S.), Department of Pediatrics (R.d.H., J.A.M.S.), and Department of Internal Medicine, Radboud Institute for Health Sciences (G.A.R.), Radboud University Medical Center, Nijmegen, The Netherlands
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6
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Liang X, Lv Y, Zhang Z, Yi H, Liu T, Li R, Yu Z, Zhang L. Study on intestinal survival and cholesterol metabolism of probiotics. Lebensm Wiss Technol 2020. [DOI: 10.1016/j.lwt.2020.109132] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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7
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Liang X, Zhang Z, Zhou X, Lu Y, Li R, Yu Z, Tong L, Gong P, Yi H, Liu T, Zhang L. Probiotics improved hyperlipidemia in mice induced by a high cholesterol diet via downregulating FXR. Food Funct 2020; 11:9903-9911. [PMID: 33094788 DOI: 10.1039/d0fo02255a] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Bifidobacterium animalis subsp. Lactis F1-7 (F1-7) could alleviate hyperlipidemia through LXR/NPC1L1 pathway and FXR/FGF15/CYP7A1 pathway.
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Affiliation(s)
- Xi Liang
- College of Food Science and Engineering
- Ocean University of China
- Qingdao
- China
| | - Zhe Zhang
- College of Food Science and Engineering
- Ocean University of China
- Qingdao
- China
| | | | - Youyou Lu
- College of Food Science and Engineering
- Ocean University of China
- Qingdao
- China
| | - Rui Li
- The Affiliated Hospital of Qingdao University
- Qingdao
- China
| | - Zhuang Yu
- The Affiliated Hospital of Qingdao University
- Qingdao
- China
| | - Lingjun Tong
- College of Food Science and Engineering
- Ocean University of China
- Qingdao
- China
| | - Pimin Gong
- College of Food Science and Engineering
- Ocean University of China
- Qingdao
- China
| | - Huaxi Yi
- College of Food Science and Engineering
- Ocean University of China
- Qingdao
- China
| | - Tongjie Liu
- College of Food Science and Engineering
- Ocean University of China
- Qingdao
- China
| | - Lanwei Zhang
- College of Food Science and Engineering
- Ocean University of China
- Qingdao
- China
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8
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Garbacz WG, Uppal H, Yan J, Xu M, Ren S, Stolz DB, Huang M, Xie W. Chronic Activation of Liver X Receptor Sensitizes Mice to High Cholesterol Diet-Induced Gut Toxicity. Mol Pharmacol 2018; 94:1145-1154. [PMID: 30045953 DOI: 10.1124/mol.118.112672] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/16/2018] [Indexed: 11/22/2022] Open
Abstract
Cholesterol is essential for numerous biologic functions and processes, but an excess of intracellular cholesterol can be toxic. Intestinal cholesterol absorption is a major determinant of plasma cholesterol level. The liver X receptor (LXR) is a nuclear receptor known for its activity in cholesterol efflux and reverse cholesterol transport. In this study, we uncovered a surprising function of LXR in intestinal cholesterol absorption and toxicity. Genetic or pharmacologic activation of LXRα-sensitized mice to a high-cholesterol diet (HCD) induced intestinal toxicity and tissue damage, including the disruption of enterocyte tight junctions, whereas the same HCD caused little toxicity in the absence of LXR activation. The gut toxicity in HCD-fed LXR-KI mice may have been accounted for by the increased intestinal cholesterol absorption and elevation of enterocyte and systemic levels of free cholesterol. The increased intestinal cholesterol absorption preceded the gut toxicity, suggesting that the increased absorption was not secondary to tissue damage. The heightened sensitivity to HCD in the HCD-fed LXRα-activated mice appeared to be intestine-specific because the liver was not affected despite activation of the same receptor in this tissue. Moreover, heightened sensitivity to HCD cannot be reversed by ezetimibe, a Niemann-Pick C1-like 1 inhibitor that inhibits intestinal cholesterol absorption, suggesting that the increased cholesterol absorption in LXR-activated intestine is mediated by a mechanism that has yet to be defined.
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Affiliation(s)
- Wojciech G Garbacz
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences (W.G.G., H.U., J.Y., M.X., S.R., W.X.), Departments of Cell Biology and Physiology (D.B.S.) and Pharmacology and Chemical Biology (W.X.), University of Pittsburgh, Pittsburgh, Pennsylvania; and Institute of Clinical Pharmacology and Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-Sen University, Guangzhou, China (M.H.)
| | - Hirdesh Uppal
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences (W.G.G., H.U., J.Y., M.X., S.R., W.X.), Departments of Cell Biology and Physiology (D.B.S.) and Pharmacology and Chemical Biology (W.X.), University of Pittsburgh, Pittsburgh, Pennsylvania; and Institute of Clinical Pharmacology and Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-Sen University, Guangzhou, China (M.H.)
| | - Jiong Yan
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences (W.G.G., H.U., J.Y., M.X., S.R., W.X.), Departments of Cell Biology and Physiology (D.B.S.) and Pharmacology and Chemical Biology (W.X.), University of Pittsburgh, Pittsburgh, Pennsylvania; and Institute of Clinical Pharmacology and Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-Sen University, Guangzhou, China (M.H.)
| | - Meishu Xu
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences (W.G.G., H.U., J.Y., M.X., S.R., W.X.), Departments of Cell Biology and Physiology (D.B.S.) and Pharmacology and Chemical Biology (W.X.), University of Pittsburgh, Pittsburgh, Pennsylvania; and Institute of Clinical Pharmacology and Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-Sen University, Guangzhou, China (M.H.)
| | - Songrong Ren
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences (W.G.G., H.U., J.Y., M.X., S.R., W.X.), Departments of Cell Biology and Physiology (D.B.S.) and Pharmacology and Chemical Biology (W.X.), University of Pittsburgh, Pittsburgh, Pennsylvania; and Institute of Clinical Pharmacology and Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-Sen University, Guangzhou, China (M.H.)
| | - Donna B Stolz
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences (W.G.G., H.U., J.Y., M.X., S.R., W.X.), Departments of Cell Biology and Physiology (D.B.S.) and Pharmacology and Chemical Biology (W.X.), University of Pittsburgh, Pittsburgh, Pennsylvania; and Institute of Clinical Pharmacology and Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-Sen University, Guangzhou, China (M.H.)
| | - Min Huang
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences (W.G.G., H.U., J.Y., M.X., S.R., W.X.), Departments of Cell Biology and Physiology (D.B.S.) and Pharmacology and Chemical Biology (W.X.), University of Pittsburgh, Pittsburgh, Pennsylvania; and Institute of Clinical Pharmacology and Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-Sen University, Guangzhou, China (M.H.)
| | - Wen Xie
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences (W.G.G., H.U., J.Y., M.X., S.R., W.X.), Departments of Cell Biology and Physiology (D.B.S.) and Pharmacology and Chemical Biology (W.X.), University of Pittsburgh, Pittsburgh, Pennsylvania; and Institute of Clinical Pharmacology and Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-Sen University, Guangzhou, China (M.H.)
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9
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Hiebl V, Ladurner A, Latkolik S, Dirsch VM. Natural products as modulators of the nuclear receptors and metabolic sensors LXR, FXR and RXR. Biotechnol Adv 2018; 36:1657-1698. [PMID: 29548878 DOI: 10.1016/j.biotechadv.2018.03.003] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 03/02/2018] [Accepted: 03/08/2018] [Indexed: 01/25/2023]
Abstract
Nuclear receptors (NRs) represent attractive targets for the treatment of metabolic syndrome-related diseases. In addition, natural products are an interesting pool of potential ligands since they have been refined under evolutionary pressure to interact with proteins or other biological targets. This review aims to briefly summarize current basic knowledge regarding the liver X (LXR) and farnesoid X receptors (FXR) that form permissive heterodimers with retinoid X receptors (RXR). Natural product-based ligands for these receptors are summarized and the potential of LXR, FXR and RXR as targets in precision medicine is discussed.
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Affiliation(s)
- Verena Hiebl
- University of Vienna, Department of Pharmacognosy, Althanstrasse 14, 1090 Vienna, Austria
| | - Angela Ladurner
- University of Vienna, Department of Pharmacognosy, Althanstrasse 14, 1090 Vienna, Austria.
| | - Simone Latkolik
- University of Vienna, Department of Pharmacognosy, Althanstrasse 14, 1090 Vienna, Austria
| | - Verena M Dirsch
- University of Vienna, Department of Pharmacognosy, Althanstrasse 14, 1090 Vienna, Austria
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10
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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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11
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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: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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12
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Takei K, Nakagawa Y, Wang Y, Han SI, Satoh A, Sekiya M, Matsuzaka T, Shimano H. Effects of K-877, a novel selective PPARα modulator, on small intestine contribute to the amelioration of hyperlipidemia in low-density lipoprotein receptor knockout mice. J Pharmacol Sci 2017; 133:214-222. [PMID: 28366492 DOI: 10.1016/j.jphs.2017.02.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/26/2017] [Accepted: 02/06/2017] [Indexed: 11/18/2022] Open
Abstract
Peroxisome proliferator-activated receptor α (PPARα) is a well-known therapeutic target for treating hyperlipidemia. K-877 is a novel selective PPARα modulator (SPPARMα) that enhances PPARα transcriptional activity with high selectivity and potency, resulting in reduced plasma lipid levels. This study aimed to evaluate the effects of K-877 on hyperlipidemia in low-density lipoprotein receptor knockout (Ldlr-/-) mice, a mouse model of atherosclerosis. We revealed that K-877 administration significantly decreased plasma triglyceride (TG) and total cholesterol (TC) levels and increased plasma high-density lipoprotein cholesterol (HDL-C) levels in Ldlr-/- mice. K-877 administration to Ldlr-/- mice efficiently increased the gene expression of PPARα and its target genes related to fatty acid oxidation in the liver and small intestine. The same treatment significantly increased ATP-binding cassette a1 gene expression in the liver and small intestine and reduced Niemann Pick C1-like 1 gene expression in the small intestine, suggesting that K-877 administration induced HDL-C production in the liver and small intestine and reduced cholesterol absorption in the small intestine. In conclusion, K-877 administration had pronounced effects on the liver and small intestine in Ldlr-/- mice. K-877 is an attractive PPARα-modulating drug for treating hyperlipidemia that works equally well in both the liver and small intestine.
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Affiliation(s)
- Kenta Takei
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Yoshimi Nakagawa
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan; International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
| | - Yunong Wang
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Song-Iee Han
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Aoi Satoh
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Motohiro Sekiya
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Takashi Matsuzaka
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Hitoshi Shimano
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan; International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan; Life Science Center, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan.
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13
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Shimabukuro M, Okawa C, Yamada H, Yanagi S, Uematsu E, Sugasawa N, Kurobe H, Hirata Y, Kim-Kaneyama JR, Lei XF, Takao S, Tanaka Y, Fukuda D, Yagi S, Soeki T, Kitagawa T, Masuzaki H, Sato M, Sata M. The pathophysiological role of oxidized cholesterols in epicardial fat accumulation and cardiac dysfunction: a study in swine fed a high caloric diet with an inhibitor of intestinal cholesterol absorption, ezetimibe. J Nutr Biochem 2016; 35:66-73. [DOI: 10.1016/j.jnutbio.2016.05.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 04/29/2016] [Accepted: 05/19/2016] [Indexed: 12/25/2022]
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14
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Abstract
The liver X receptors (LXR) are crucial regulators of metabolism. After ligand binding, they regulate gene transcription and thereby mediate changes in metabolic pathways. Modulation of LXR and their downstream targets has appeared to be a promising treatment for metabolic diseases especially atherosclerosis and cholesterol metabolism. However, the complexity of LXR action in various metabolic tissues and the liver side effect of LXR activation have slowed down the interest for LXR drugs. In this review, we summarized the role of LXR in the main metabolically active tissues with a special focus on obesity and associated diseases in mammals. We will also discuss the dual interplay between the two LXR isoforms suggesting that they may collaborate to establish a fine and efficient system for the maintenance of metabolism homeostasis.
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15
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Wang J, Wang D, Tan Y, Zhao G, Ji Z. Pioglitazone reduces lipid droplets in cholesterolosis of the gallbladder by increasing ABCA1 and NCEH1 expression. Mol Cell Biochem 2015; 399:7-15. [DOI: 10.1007/s11010-014-2225-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 09/27/2014] [Indexed: 01/12/2023]
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