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Tang X, Yan T, Wang S, Liu Q, Yang Q, Zhang Y, Li Y, Wu Y, Liu S, Ma Y, Yang L. Treatment with β-sitosterol ameliorates the effects of cerebral ischemia/reperfusion injury by suppressing cholesterol overload, endoplasmic reticulum stress, and apoptosis. Neural Regen Res 2024; 19:642-649. [PMID: 37721296 PMCID: PMC10581587 DOI: 10.4103/1673-5374.380904] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 03/30/2023] [Accepted: 05/27/2023] [Indexed: 09/19/2023] Open
Abstract
β-Sitosterol is a type of phytosterol that occurs naturally in plants. Previous studies have shown that it has anti-oxidant, anti-hyperlipidemic, anti-inflammatory, immunomodulatory, and anti-tumor effects, but it is unknown whether β-sitosterol treatment reduces the effects of ischemic stroke. Here we found that, in a mouse model of ischemic stroke induced by middle cerebral artery occlusion, β-sitosterol reduced the volume of cerebral infarction and brain edema, reduced neuronal apoptosis in brain tissue, and alleviated neurological dysfunction; moreover, β-sitosterol increased the activity of oxygen- and glucose-deprived cerebral cortex neurons and reduced apoptosis. Further investigation showed that the neuroprotective effects of β-sitosterol may be related to inhibition of endoplasmic reticulum stress caused by intracellular cholesterol accumulation after ischemic stroke. In addition, β-sitosterol showed high affinity for NPC1L1, a key transporter of cholesterol, and antagonized its activity. In conclusion, β-sitosterol may help treat ischemic stroke by inhibiting neuronal intracellular cholesterol overload/endoplasmic reticulum stress/apoptosis signaling pathways.
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Affiliation(s)
- Xiuling Tang
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Tao Yan
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Saiying Wang
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Qingqing Liu
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Qi Yang
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Yongqiang Zhang
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Yujiao Li
- Department of Clinical Pharmacy, Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu Province, China
| | - Yumei Wu
- Department of Pharmacology, School of Pharmacy, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Shuibing Liu
- Department of Pharmacology, School of Pharmacy, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Yulong Ma
- Department of Anesthesiology, The First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Le Yang
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi’an, Shaanxi Province, China
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, Air Force Medical University, Xi’an, Shaanxi Province, China
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2
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Rosales C, Yelamanchili D, Gillard BK, Liu J, Gotto AM, Pownall HJ. Serum opacity factor rescues fertility among female Scarb1 -/- mice by reducing HDL-free cholesterol bioavailability. J Lipid Res 2023; 64:100327. [PMID: 36596339 PMCID: PMC9932678 DOI: 10.1016/j.jlr.2022.100327] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 11/08/2022] [Accepted: 12/05/2022] [Indexed: 01/02/2023] Open
Abstract
Human female infertility, 20% of which is idiopathic, is a public health problem for which better diagnostics and therapeutics are needed. A novel cause of infertility emerged from studies of female mice deficient in the HDL receptor gene (Scarb1). These mice are infertile and have high plasma HDL cholesterol (C) concentrations, due to elevated HDL-free cholesterol (FC), which transfers from HDL to all tissues. Previous studies have indicated that oral delivery of probucol, an HDL-lowering drug, to female Scarb1-/- mice reduces plasma HDL-C concentrations and rescues fertility. Additionally, serum opacity factor (SOF), a bacterial virulence factor, disrupts HDL structure, and bolus SOF injection into mice reduces plasma HDL-C concentrations. Here, we discovered that delivering SOF to female Scarb1-/- mice with an adeno-associated virus (AAVSOF) induces constitutive SOF expression, reduces HDL-FC concentrations, and rescues fertility while normalizing ovary morphology. Although AAVSOF did not alter ovary-FC content, the ovary-mol% FC correlated with plasma HDL-mol% FC in a fertility-dependent way. Therefore, reversing the abnormal plasma microenvironment of high plasma HDL-mol% FC in female Scarb1-/- mice rescues fertility. These data provide the rationale to search for similar mechanistic links between HDL-mol% FC and infertility and the rescue of fertility in women by reducing plasma HDL-mol% FC.
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Affiliation(s)
- Corina Rosales
- Center for Bioenergetics and the Department of Medicine, Houston Methodist Research Institute, Houston, TX, USA; Weill Cornell Medicine, Department of Medicine, New York, NY, USA.
| | - Dedipya Yelamanchili
- Center for Bioenergetics and the Department of Medicine, Houston Methodist Research Institute, Houston, TX, USA
| | - Baiba K Gillard
- Center for Bioenergetics and the Department of Medicine, Houston Methodist Research Institute, Houston, TX, USA; Weill Cornell Medicine, Department of Medicine, New York, NY, USA
| | - Jing Liu
- Center for Bioenergetics and the Department of Medicine, Houston Methodist Research Institute, Houston, TX, USA
| | - Antonio M Gotto
- Weill Cornell Medicine, Department of Medicine, New York, NY, USA
| | - Henry J Pownall
- Center for Bioenergetics and the Department of Medicine, Houston Methodist Research Institute, Houston, TX, USA; Weill Cornell Medicine, Department of Medicine, New York, NY, USA
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3
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Yue X, Kong Y, Zhang Y, Sun M, Liu S, Wu Z, Gao L, Liang X, Ma C. SREBF2-STARD4 axis confers sorafenib resistance in hepatocellular carcinoma by regulating mitochondrial cholesterol homeostasis. Cancer Sci 2022; 114:477-489. [PMID: 35642354 PMCID: PMC9899602 DOI: 10.1111/cas.15449] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [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: 03/04/2022] [Revised: 05/21/2022] [Accepted: 05/26/2022] [Indexed: 01/07/2023] Open
Abstract
Sorafenib resistance limits its survival benefit for treatment of hepatocellular carcinoma (HCC). Cholesterol metabolism is dysregulated in HCC, and its role in sorafenib resistance of HCC has not been fully elucidated. Aiming to elucidate this, in vitro and in vivo sorafenib resistant models were established. Sterol regulatory element binding transcription factor 2 (SREBF2), the key regulator of cholesterol metabolism, was activated in sorafenib resistant HepG2 and Huh7 cells. Knockdown of SREBF2 resensitized sorafenib resistant cells and xenografts tumors to sorafenib. Further study showed that SREBF2 positively correlated with StAR related lipid transfer domain containing 4 (STARD4) in our sorafenib resistant models and publicly available datasets. STARD4, mediating cholesterol trafficking, not only promoted proliferation and migration of HepG2 and Huh7 cells, but also increased sorafenib resistance in liver cancer. Mechanically, SREBF2 promoted expression of STARD4 by directly binding to its promoter region, leading to increased mitochondrial cholesterol levels and inhibition of mitochondrial cytochrome c release. Importantly, knockdown of SREBF2 or STARD4 decreased mitochondrial cholesterol levels and increased mitochondrial cytochrome c release, respectively. Moreover, overexpression of STARD4 reversed the effect of SREBF2 knockdown on mitochondrial cytochrome c release and sorafenib resistance. In conclusion, SREBF2 promotes STARD4 transcription, which in turn contributes to mitochondrial cholesterol transport and sorafenib resistance in HCC. Therefore, targeting the SREBF2-STARD4 axis would be beneficial to a subset of HCC patients with sorafenib resistance.
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Affiliation(s)
- Xuetian Yue
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of MedicineShandong UniversityJinanChina
| | - Youzi Kong
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of MedicineShandong UniversityJinanChina
| | - Yankun Zhang
- Key Laboratory for Experimental Teratology of Ministry of Education, Key Laboratory of Infection and Immunity of Shandong Province, and Department of Immunology, School of Basic Medical Sciences, Cheeloo Medical College of MedicineShandong UniversityJinanChina
| | - Min Sun
- Department of Hernia and Abdominal Wall Surgery, General Surgery, Qilu Hospital, Cheeloo College of MedicineShandong UniversityJinanChina
| | - Shuyue Liu
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of MedicineShandong UniversityJinanChina
| | - Zhuanchang Wu
- Key Laboratory for Experimental Teratology of Ministry of Education, Key Laboratory of Infection and Immunity of Shandong Province, and Department of Immunology, School of Basic Medical Sciences, Cheeloo Medical College of MedicineShandong UniversityJinanChina
| | - Lifen Gao
- Key Laboratory for Experimental Teratology of Ministry of Education, Key Laboratory of Infection and Immunity of Shandong Province, and Department of Immunology, School of Basic Medical Sciences, Cheeloo Medical College of MedicineShandong UniversityJinanChina
| | - Xiaohong Liang
- Key Laboratory for Experimental Teratology of Ministry of Education, Key Laboratory of Infection and Immunity of Shandong Province, and Department of Immunology, School of Basic Medical Sciences, Cheeloo Medical College of MedicineShandong UniversityJinanChina
| | - Chunhong Ma
- Key Laboratory for Experimental Teratology of Ministry of Education, Key Laboratory of Infection and Immunity of Shandong Province, and Department of Immunology, School of Basic Medical Sciences, Cheeloo Medical College of MedicineShandong UniversityJinanChina
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4
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Lan Y, Qian B, Huang HY, Wang P, Li T, Yuan Q, Zhang HY, Lin YC, Lin ZN. Hepatocyte-Derived Prostaglandin E2-Modulated Macrophage M1-Type Polarization via mTOR-NPC1 Axis-Regulated Cholesterol Transport from Lysosomes to the Endoplasmic Reticulum in Hepatitis B Virus x Protein-Related Nonalcoholic Steatohepatitis. Int J Mol Sci 2022; 23:11660. [PMID: 36232960 DOI: 10.3390/ijms231911660] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 11/17/2022] Open
Abstract
Lipid metabolic dysregulation and liver inflammation have been reported to be associated with nonalcoholic steatohepatitis (NASH), but the underlying mechanisms remain unclear. Hepatitis B virus x protein (HBx) is a risk factor for NASH. Based on metabolomic and transcriptomic screens and public database analysis, we found that HBx-expressing hepatocyte-derived prostaglandin E2 (PGE2) induced macrophage polarization imbalance via prostaglandin E2 receptor 4 (EP4) through in vitro, ex vivo, and in vivo models. Here, we revealed that the M1-type polarization of macrophages induced by endoplasmic reticulum oxidoreductase-1-like protein α (ERO1α)-dependent endoplasmic reticulum stress was associated with the HBx-related hepatic NASH phenotype. Mechanistically, HBx promoted Niemann-Pick type C1 (NPC1)/oxysterol-binding protein-related protein 5 (ORP5)-mediated cholesterol transport from the lysosome to the endoplasmic reticulum via mammalian target of rapamycin (mTOR) activation. This study provides a novel basis for screening potential biomarkers in the macrophage mTOR-cholesterol homeostasis-polarization regulatory signaling pathway and evaluating targeted interventions for HBx-associated NASH.
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Abstract
NPC1 plays a central role in cholesterol egress from endolysosomes, a critical step for maintaining intracellular cholesterol homeostasis. Despite recent advances in the field, the full repertoire of molecules and pathways involved in this process remains unknown. Emerging evidence suggests the existence of NPC1-independent, alternative routes. These may involve vesicular and non-vesicular mechanisms, as well as release of extracellular vesicles. Understanding the underlying molecular mechanisms that bypass NPC1 function could have important implications for the development of therapies for lysosomal storage disorders. Here we discuss how cholesterol may be exported from lysosomes in which NPC1 function is impaired.
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Affiliation(s)
- Albert Lu
- Departament de Biomedicina, Unitat de Biologia Cellular, Facultat de Medicina i Ciències de la Salut, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Universitat de Barcelona, Barcelona, Spain
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6
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Poznyak AV, Kashirskikh DA, Sukhorukov VN, Kalmykov V, Omelchenko AV, Orekhov AN. Cholesterol Transport Dysfunction and Its Involvement in Atherogenesis. Int J Mol Sci 2022; 23:ijms23031332. [PMID: 35163256 PMCID: PMC8836120 DOI: 10.3390/ijms23031332] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/17/2022] [Accepted: 01/23/2022] [Indexed: 12/26/2022] Open
Abstract
Atherosclerosis is the cause of the development of serious cardiovascular disorders, leading to disability and death. Numerous processes are involved in the pathogenesis of atherosclerosis, including inflammation, endothelial dysfunction, oxidative stress, and lipid metabolism disorders. Reverse transport of cholesterol is a mechanism presumably underlying the atheroprotective effect of high-density lipoprotein. In this review, we examined disorders of cholesterol metabolism and their possible effect on atherogenesis. We paid special attention to the reverse transport of cholesterol. Transformed cholesterol metabolism results in dyslipidemia and early atherosclerosis. Reverse cholesterol transport is an endogenous mechanism by which cells export cholesterol and maintain homeostasis. It is known that one of the main factors leading to the formation of atherosclerotic plaques on the walls of blood vessels are multiple modifications of low-density lipoprotein, and the formation of foam cells following them.
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Affiliation(s)
- Anastasia V. Poznyak
- Institute for Atherosclerosis Research, Osennyaya Street 4-1-207, 121609 Moscow, Russia;
- Correspondence: (A.V.P.); (A.N.O.)
| | - Dmitry A. Kashirskikh
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, 125315 Moscow, Russia; (D.A.K.); (V.K.)
| | - Vasily N. Sukhorukov
- AP Avtsyn Research Institute of Human Morphology, 3 Tsyurupa Street, 117418 Moscow, Russia;
| | - Vladislav Kalmykov
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, 125315 Moscow, Russia; (D.A.K.); (V.K.)
- AP Avtsyn Research Institute of Human Morphology, 3 Tsyurupa Street, 117418 Moscow, Russia;
| | - Andrey V. Omelchenko
- Institute for Atherosclerosis Research, Osennyaya Street 4-1-207, 121609 Moscow, Russia;
| | - Alexander N. Orekhov
- Institute for Atherosclerosis Research, Osennyaya Street 4-1-207, 121609 Moscow, Russia;
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, 125315 Moscow, Russia; (D.A.K.); (V.K.)
- AP Avtsyn Research Institute of Human Morphology, 3 Tsyurupa Street, 117418 Moscow, Russia;
- Correspondence: (A.V.P.); (A.N.O.)
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7
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Lu A. Sorting (Nexin-13) out Novel Insights into Endolysosomal Cholesterol Export. Contact (Thousand Oaks) 2022; 5:25152564221114513. [PMID: 37366510 PMCID: PMC10243570 DOI: 10.1177/25152564221114513] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/28/2022] [Accepted: 07/21/2022] [Indexed: 06/28/2023]
Abstract
Transport in and out of the endolysosomal compartment represents a key step in the regulation of cellular cholesterol homeostasis. Despite important recent advances, how LDL-derived, free cholesterol is exported from the lumen of endolysosomes to other organelles is still a matter of debate. We recently devised a CRISPR/Cas9 genome-scale strategy to uncover genes involved in the regulation of endolysosomal cholesterol homeostasis and the functionally linked phospholipid, bis(monoacylglycerol)-phosphate. This approach confirmed known genes and pathways involved in this process, and more importantly revealed previously unrecognized roles for new players, such as Sorting Nexin-13 (SNX13). Here we discuss the unexpected regulatory role of SNX13 in endolysosomal cholesterol export.
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Affiliation(s)
- Albert Lu
- Departament de Biomedicina, Unitat de Biologia Cel·lular,
Facultat de Medicina i Ciències de la Salut, Centre de Recerca Biomèdica CELLEX, Institut
d’Investigacions Biomèdiques August Pi i Sunyer, Universitat de Barcelona, Barcelona, Spain
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8
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Papatheodorou P, Kindig S, Badilla-Lobo A, Fischer S, Durgun E, Thuraisingam T, Witte A, Song S, Aktories K, Chaves-Olarte E, Rodríguez C, Barth H. The Compound U18666A Inhibits the Intoxication of Cells by Clostridioides difficile Toxins TcdA and TcdB. Front Microbiol 2021; 12:784856. [PMID: 34912322 PMCID: PMC8667575 DOI: 10.3389/fmicb.2021.784856] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 09/28/2021] [Accepted: 11/01/2021] [Indexed: 11/13/2022] Open
Abstract
The intestinal pathogen Clostridioides (C.) difficile is a major cause of diarrhea both in hospitals and outpatient in industrialized countries. This bacterium produces two large exotoxins, toxin A (TcdA) and toxin B (TcdB), which are directly responsible for the onset of clinical symptoms of C. difficile-associated diseases (CDADs), such as antibiotics-associated diarrhea and the severe, life-threatening pseudomembranous colitis. Both toxins are multidomain proteins and taken up into host eukaryotic cells via receptor-mediated endocytosis. Within the cell, TcdA and TcdB inactivate Rho and/or Ras protein family members by glucosylation, which eventually results in cell death. The cytotoxic mode of action of the toxins is the main reason for the disease. Thus, compounds capable of inhibiting the cellular uptake and/or mode-of-action of both toxins are of high therapeutic interest. Recently, we found that the sterol regulatory element-binding protein 2 (SREBP-2) pathway, which regulates cholesterol content in membranes, is crucial for the intoxication of cells by TcdA and TcdB. Furthermore, it has been shown that membrane cholesterol is required for TcdA- as well as TcdB-mediated pore formation in endosomal membranes, which is a key step during the translocation of the glucosyltransferase domain of both toxins from endocytic vesicles into the cytosol of host cells. In the current study, we demonstrate that intoxication by TcdA and TcdB is diminished in cultured cells preincubated with the compound U18666A, an established inhibitor of cholesterol biosynthesis and/or intracellular transport. U18666A-pretreated cells were also less sensitive against TcdA and TcdB variants from the epidemic NAP1/027 C. difficile strain. Our study corroborates the crucial role of membrane cholesterol for cell entry of TcdA and TcdB, thus providing a valuable basis for the development of novel antitoxin strategies in the context of CDADs.
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Affiliation(s)
| | - Selina Kindig
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, Ulm, Germany
| | - Adriana Badilla-Lobo
- Centro de Investigación en Enfermedades Tropicales and Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Stephan Fischer
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, Ulm, Germany
| | - Ebru Durgun
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, Ulm, Germany
| | - Tharani Thuraisingam
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, Ulm, Germany
| | - Alexander Witte
- Institute of Experimental and Clinical Pharmacology and Toxicology, Albert Ludwig University Freiburg, Freiburg, Germany
| | - Shuo Song
- Institute of Experimental and Clinical Pharmacology and Toxicology, Albert Ludwig University Freiburg, Freiburg, Germany
| | - Klaus Aktories
- Institute of Experimental and Clinical Pharmacology and Toxicology, Albert Ludwig University Freiburg, Freiburg, Germany
| | - Esteban Chaves-Olarte
- Centro de Investigación en Enfermedades Tropicales and Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - César Rodríguez
- Centro de Investigación en Enfermedades Tropicales and Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Holger Barth
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, Ulm, Germany
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Inokuchi JI, Kanoh H, Inamori KI, Nagafuku M, Nitta T, Fukase K. Homeostatic and pathogenic roles of the GM3 ganglioside. FEBS J 2021; 289:5152-5165. [PMID: 34125497 DOI: 10.1111/febs.16076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/10/2021] [Accepted: 06/14/2021] [Indexed: 12/14/2022]
Abstract
Two decades ago, we achieved molecular cloning of ganglioside GM3 synthase (GM3S; ST3GAL5), the enzyme responsible for initiating biosynthesis of complex gangliosides. The efforts of our research group since then have been focused on clarifying the physiological and pathological roles of gangliosides, particularly GM3. This review summarizes our long-term studies on the roles of GM3 in insulin resistance and adipogenesis in adipose tissues, cholesterol uptake in intestine, and leptin resistance in hypothalamus. We hypothesized that GM3 plays a role in innate immune function of macrophages and demonstrated that molecular species of GM3 with differing acyl-chain structures and modifications functioned as pro- and anti-inflammatory endogenous Toll-like receptor 4 (TLR4) modulators in macrophages. Very-long-chain and α-hydroxy GM3 species enhanced TLR4 activation, whereas long-chain and unsaturated GM3 species counteracted this effect. Lipidomic analyses of serum and adipose tissues revealed that imbalances between such pro- and anti-inflammatory GM3 species promoted progression of metabolic disorders. GM3 thus functions as a physiological regulatory factor controlling the balance between homeostatic and pathological states. Ongoing studies based on these findings will clarify the mechanisms underlying ganglioside-dependent control of energy homeostasis and innate immune responses.
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Affiliation(s)
- Jin-Ichi Inokuchi
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Japan.,Core for Medicine and Science Collaborative Research and Education (MS-CORE), Project Research Center for Fundamental Sciences, Osaka University, Japan
| | - Hirotaka Kanoh
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Kei-Ichiro Inamori
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Masakazu Nagafuku
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Takahiro Nitta
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Koichi Fukase
- Core for Medicine and Science Collaborative Research and Education (MS-CORE), Project Research Center for Fundamental Sciences, Osaka University, Japan.,Department of Chemistry, Graduate School of Science, Osaka University, Japan
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10
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Schlüter KD, Wolf A, Schreckenberg R. Coming Back to Physiology: Extra Hepatic Functions of Proprotein Convertase Subtilisin/Kexin Type 9. Front Physiol 2020; 11:598649. [PMID: 33364976 PMCID: PMC7750466 DOI: 10.3389/fphys.2020.598649] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [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: 08/25/2020] [Accepted: 11/09/2020] [Indexed: 12/18/2022] Open
Abstract
Neuronal apoptosis regulated convertase-1 (NARC-1), now mostly known as proprotein convertase subtilisin/kexin type 9 (PCSK9), has received a lot of attention due to the fact that it is a key regulator of the low-density lipoprotein (LDL) receptor (LDL-R) and is therefore involved in hepatic LDL clearance. Within a few years, therapies targeting PCSK9 have reached clinical practice and they offer an additional tool to reduce blood cholesterol concentrations. However, PCSK9 is almost ubiquitously expressed in the body but has less well-understood functions and target proteins in extra hepatic tissues. As such, PCSK9 is involved in the regulation of neuronal survival and protein degradation, it affects the expression of the epithelial sodium channel (ENaC) in the kidney, it interacts with white blood cells and with cells of the vascular wall, and it modifies contractile activity of cardiomyocytes, and contributes to the regulation of cholesterol uptake in the intestine. Moreover, under stress conditions, signals from the kidney and heart can affect hepatic expression and thereby the plasma concentration of PCSK9 which then in turn can affect other target organs. Therefore, there is an intense relationship between the local (autocrine) and systemic (endocrine) effects of PCSK9. Although, PCSK9 has been recognized as a ubiquitously expressed modifier of cellular function and signaling molecules, its physiological role in different organs is not well-understood. The current review summarizes these findings.
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Affiliation(s)
| | - Annemarie Wolf
- Institute of Physiology, Justus-Liebig-University, Gießen, Germany
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11
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Wang Y, Zhang X, Wang T, Liu W, Wang L, Hao L, Ju M, Xiao R. 27-Hydroxycholesterol Promotes the Transfer of Astrocyte-Derived Cholesterol to Neurons in Co-cultured SH-SY5Y Cells and C6 Cells. Front Cell Dev Biol 2020; 8:580599. [PMID: 33330456 PMCID: PMC7732486 DOI: 10.3389/fcell.2020.580599] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [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: 07/06/2020] [Accepted: 10/28/2020] [Indexed: 12/14/2022] Open
Abstract
Abnormality in cholesterol homeostasis in the brain is a feature of Alzheimer’s disease (AD). 27-Hydroxycholesterol (27-OHC) has been identified as a possible biomarker of AD, but its effects on cholesterol metabolism have not been fully characterized. This study was aimed to investigate the impacts of 27-OHC on cholesterol metabolism in nerve cells. SH-SY5Y cells and C6 cells were co-cultured and treated with 5, 10, and 20 μM 27-OHC for 24 h. Results showed that 27-OHC decreased cholesterol levels and up-regulated the expression of transport-related proteins in C6 cells. In SH-SY5Y cells, 27-OHC increased cholesterol accumulation, especially on plasma membrane (PM), which was consistent with the up-regulation of expressions of cholesterol endocytosis receptors, lipid raft-related proteins, and cholesterol esterase. Simultaneously, accumulation of membrane cholesterol promoted cholesterol conversion to 24S-OHC by CYP46A1(24S-hydroxylase) transfer from the endoplasmic reticulum (ER) to PM. Besides, Aβ levels were elevated in SH-SY5Y cells after 27-OHC treatment. Our results suggest that 27-OHC motivates the transfer of astrocyte-derived cholesterol to neurons. Although there exists a feedback mechanism that excessive cholesterol promotes its conversion to 24S-OHC, the increased cholesterol induced by 27-OHC could not be wholly offset in neurons.
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Affiliation(s)
- Yushan Wang
- School of Public Health, Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, China
| | - Xiaona Zhang
- School of Public Health, Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, China
| | - Tao Wang
- School of Public Health, Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, China
| | - Wen Liu
- School of Public Health, Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, China
| | - Lijing Wang
- School of Public Health, Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, China
| | - Ling Hao
- School of Public Health, Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, China
| | - Mengwei Ju
- School of Public Health, Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, China
| | - Rong Xiao
- School of Public Health, Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, China
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12
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Lee HR, Lee Y, Oh SS, Choi SQ. Ultra-Stable Freestanding Lipid Membrane Array: Direct Visualization of Dynamic Membrane Remodeling with Cholesterol Transport and Enzymatic Reactions. Small 2020; 16:e2002541. [PMID: 32924281 DOI: 10.1002/smll.202002541] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/09/2020] [Indexed: 06/11/2023]
Abstract
Cell membranes actively change their local compositions, serving essential biological processes such as cellular signaling and endocytosis. Although membrane dynamics is vital in the cellular functions, the complexity of natural membranes has made its fundamental understanding and systematic assessment difficult. Here, a powerful artificial membrane system is developed for real-time visualization of the spatiotemporal dynamics of membrane remodeling. Through well-defined air/oil/water interfaces on grid holes, tens of planar lipid bilayer membranes are easily created, and their reproducibility, controllability, and generality are highlighted. The freestanding membranes are large but also highly stable, facilitating direct long-term monitoring of dynamic membrane reconstitution caused by external stimuli. As an example to demonstrate the superiority of this membrane system, the effect of cholesterol trafficking, which significantly affects biophysical properties of cell membranes, is investigated at different membrane compositions. Cholesterol transport into and out of the membranes at different rates causes anomalous lipid arrangements through cholesterol-mediated phase transitions and decomposition, which have never been witnessed before. Furthermore, enzyme-induced membrane dynamics is successfully shown in this platform; sphingomyelinases locally generate asymmetry between two membrane leaflets. This technique is broadly applicable for exploring the membrane heterogeneity under various membrane-based reactions, providing valuable insight into the membrane dynamics.
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Affiliation(s)
- Hyun-Ro Lee
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Yohan Lee
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Seung Soo Oh
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Siyoung Q Choi
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
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13
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Petrov K, Wierbowski BM, Liu J, Salic A. Distinct Cation Gradients Power Cholesterol Transport at Different Key Points in the Hedgehog Signaling Pathway. Dev Cell 2020; 55:314-327.e7. [PMID: 32860743 DOI: 10.1016/j.devcel.2020.08.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 05/07/2020] [Accepted: 07/30/2020] [Indexed: 01/20/2023]
Abstract
Cholesterol plays two critical roles in Hedgehog signaling, a fundamental pathway in animal development and cancer: it covalently modifies the Sonic hedgehog (SHH) ligand, restricting its release from producing cells, and directly activates Smoothened in responding cells. In both contexts, a membrane protein related to bacterial RND transporters regulates cholesterol: Dispatched1 controls release of cholesterylated SHH, and Patched1 antagonizes Smoothened activation by cholesterol. The mechanism and driving force for eukaryotic RND proteins, including Dispatched1 and Patched1, are unknown. Here, we show that Dispatched1 acts enzymatically to catalyze SHH release. Dispatched1 uses the energy of the plasma membrane Na+ gradient, thus functioning as an SHH/Na+ antiporter. In contrast, Patched1 repression of Smoothened requires the opposing K+ gradient. Our results clarify the transporter activity of essential eukaryotic RND proteins and demonstrate that the two main cation gradients of animal cells differentially power cholesterol transport at two crucial steps in the Hedgehog pathway.
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14
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Saha P, Shumate JL, Caldwell JG, Elghobashi-Meinhardt N, Lu A, Zhang L, Olsson NE, Elias JE, Pfeffer SR. Inter-domain dynamics drive cholesterol transport by NPC1 and NPC1L1 proteins. eLife 2020; 9:e57089. [PMID: 32410728 PMCID: PMC7228765 DOI: 10.7554/elife.57089] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 04/25/2020] [Indexed: 01/17/2023] Open
Abstract
Transport of LDL-derived cholesterol from lysosomes into the cytoplasm requires NPC1 protein; NPC1L1 mediates uptake of dietary cholesterol. We introduced single disulfide bonds into NPC1 and NPC1L1 to explore the importance of inter-domain dynamics in cholesterol transport. Using a sensitive method to monitor lysosomal cholesterol efflux, we found that NPC1's N-terminal domain need not release from the rest of the protein for efficient cholesterol export. Either introducing single disulfide bonds to constrain lumenal/extracellular domains or shortening a cytoplasmic loop abolishes transport activity by both NPC1 and NPC1L1. The widely prescribed cholesterol uptake inhibitor, ezetimibe, blocks NPC1L1; we show that residues that lie at the interface between NPC1L1's three extracellular domains comprise the drug's binding site. These data support a model in which cholesterol passes through the cores of NPC1/NPC1L1 proteins; concerted movement of various domains is needed for transfer and ezetimibe blocks transport by binding to multiple domains simultaneously.
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Affiliation(s)
- Piyali Saha
- Department of Biochemistry, Stanford University School of MedicineStanfordUnited States
| | - Justin L Shumate
- Department of Biochemistry, Stanford University School of MedicineStanfordUnited States
| | - Jenna G Caldwell
- Department of Biochemistry, Stanford University School of MedicineStanfordUnited States
| | | | - Albert Lu
- Department of Biochemistry, Stanford University School of MedicineStanfordUnited States
| | | | - Niclas E Olsson
- Department of Chemical and Systems Biology, Stanford University School of MedicineStanfordUnited States
| | | | - Suzanne R Pfeffer
- Department of Biochemistry, Stanford University School of MedicineStanfordUnited States
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15
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Li S, Xu S, Zhao Y, Wang H, Feng J. Dietary Betaine Addition Promotes Hepatic Cholesterol Synthesis, Bile Acid Conversion, and Export in Rats. Nutrients 2020; 12:nu12051399. [PMID: 32414094 PMCID: PMC7284822 DOI: 10.3390/nu12051399] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 05/11/2020] [Accepted: 05/11/2020] [Indexed: 12/25/2022] Open
Abstract
It is widely reported how betaine addition regulates lipid metabolism but how betaine affects cholesterol metabolism is still unknown. This study aimed to investigate the role of betaine in hepatic cholesterol metabolism of Sprague-Dawley rats. Rats were randomly allocated to four groups and fed with a basal diet or a high-fat diet with or without 1% betaine. The experiment lasted 28 days. The results showed that dietary betaine supplementation reduced the feed intake of rats with final weight unchanged. Serum low-density-lipoprotein cholesterol was increased with the high-fat diet. The high-fat diet promoted cholesterol synthesis and excretion by enhancing the HMG-CoA reductase and ABCG5/G8, respectively, which lead to a balance of hepatic cholesterol. Rats in betaine groups showed a higher level of hepatic total cholesterol. Dietary betaine addition enhanced cholesterol synthesis as well as conversion of bile acid from cholesterol by increasing the levels of HMGCR and CYP7A1. The high-fat diet decreased the level of bile salt export pump, while dietary betaine addition inhibited this decrease and promoted bile acid efflux and increased total bile acid levels in the intestine. In summary, dietary betaine addition promoted hepatic cholesterol metabolism, including cholesterol synthesis, conversion of bile acids, and bile acid export.
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Affiliation(s)
- Sisi Li
- Key Laboratory of Molecular Animal Nutrition, Ministry of Education, College of Animal Sciences, Zhejiang University, Hangzhou 310027, China; (S.L.); (S.X.); (Y.Z.)
| | - Shuyi Xu
- Key Laboratory of Molecular Animal Nutrition, Ministry of Education, College of Animal Sciences, Zhejiang University, Hangzhou 310027, China; (S.L.); (S.X.); (Y.Z.)
| | - Yang Zhao
- Key Laboratory of Molecular Animal Nutrition, Ministry of Education, College of Animal Sciences, Zhejiang University, Hangzhou 310027, China; (S.L.); (S.X.); (Y.Z.)
| | - Haichao Wang
- Department of Animal Science, College of Life Sciences and Food Engineering, Hebei University of Engineering, Handan 430068, China;
| | - Jie Feng
- Key Laboratory of Molecular Animal Nutrition, Ministry of Education, College of Animal Sciences, Zhejiang University, Hangzhou 310027, China; (S.L.); (S.X.); (Y.Z.)
- Correspondence: ; Tel.: +86-571-88982121
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16
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Gracia G, Cao E, Johnston APR, Porter CJH, Trevaskis NL. Organ-specific lymphatics play distinct roles in regulating HDL trafficking and composition. Am J Physiol Gastrointest Liver Physiol 2020; 318:G725-G735. [PMID: 32068443 DOI: 10.1152/ajpgi.00340.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Recently, peripheral lymphatic vessels were found to transport high-density lipoprotein (HDL) from interstitial tissues to the blood circulation during reverse cholesterol transport. This function is thought to be critical to the clearance of cholesterol from atherosclerotic plaques. The role of organ-specific lymphatics in modulating HDL transport and composition is, however, incompletely understood. This study aimed to 1) determine the contribution of the lymphatics draining the intestine and liver (which are major sites of HDL synthesis) to total (thoracic) lymph HDL transport and 2) verify whether the HDLs in lymph are derived from specific organs and are modified during trafficking in lymph. The mesenteric, hepatic, or thoracic lymph duct was cannulated in nonfasted Sprague-Dawley rats, and lymph was collected over 5 h under anesthesia. Whole lymph and specific lymph lipoproteins (isolated by ultracentrifugation) were analyzed for protein and lipid composition. The majority of thoracic lymph fluid, protein, and lipid mass was sourced from the mesenteric, and to a lesser extent, hepatic lymph. Mesenteric and thoracic lymph were both rich in chylomicrons and very low-density lipoprotein, whereas hepatic lymph and plasma were HDL-rich. The protein and lipid mass in thoracic lymph HDL was mostly sourced from mesenteric lymph, whereas the cholesterol mass was equally sourced from mesenteric and hepatic lymph. HDLs were compositionally distinct across the lymph sources and plasma. The composition of HDL also appeared to be modified during passage from the mesenteric and hepatic to the thoracic lymph duct. Overall, this study demonstrates that the lipoproteins in lymph are organ specific in composition, and the intestine and liver appear to be the main source of HDL in the lymph.NEW & NOTEWORTHY High-density lipoprotein in lymph are organ-specific in composition and derive mostly from the intestine and liver. High-density lipoprotein also appears to be remodeled during transport through the lymphatics. These findings have implications to cardiometabolic diseases that involve perturbations in lipoprotein distribution and metabolism.
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Affiliation(s)
- Gracia Gracia
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia
| | - Enyuan Cao
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia
| | - Angus P R Johnston
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia
| | - Christopher J H Porter
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia
| | - Natalie L Trevaskis
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia
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17
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Martello A, Platt FM, Eden ER. Staying in touch with the endocytic network: The importance of contacts for cholesterol transport. Traffic 2020; 21:354-363. [PMID: 32129938 PMCID: PMC8650999 DOI: 10.1111/tra.12726] [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] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/21/2020] [Accepted: 03/02/2020] [Indexed: 12/16/2022]
Abstract
Cholesterol homeostasis is critical for cell function and human health. Cholesterol is heterogeneously distributed among cellular membranes, with the redistribution of endocytosed dietary cholesterol playing a pivotal role in the regulation of cholesterol homeostasis. While gaps remain in our understanding of intracellular dietary cholesterol transport, a highly complex network of pathways is starting to emerge, often involving inter‐dependent vesicular and non‐vesicular transport mechanisms. The last decade has seen a surge in interest in non‐vesicular transport and inter‐organellar communication at membrane contact sites. By providing platforms for protein interactions, signalling events, lipid exchange and calcium flux, membrane contact sites (MCS) are now appreciated as controlling the fate of large amounts of lipid and play central roles in the regulation and co‐ordination of endocytic trafficking. Here, we review the role of MCS in multiple pathways for cholesterol export from the endocytic pathway and highlight the intriguing interplay between vesicular and non‐vesicular transport mechanisms and relationship with neurodegenerative disease.
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Affiliation(s)
| | - Fran M Platt
- Department of Pharmacology, University of Oxford, Oxford, UK
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18
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Castellanos-Castro S, Bolaños J, Orozco E. Lipids in Entamoeba histolytica: Host-Dependence and Virulence Factors. Front Cell Infect Microbiol 2020; 10:75. [PMID: 32211340 PMCID: PMC7075943 DOI: 10.3389/fcimb.2020.00075] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [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: 09/24/2019] [Accepted: 02/14/2020] [Indexed: 11/19/2022] Open
Abstract
Lipids are essential players in parasites pathogenesis. In particular, the highly phagocytic trophozoites of Entamoeba histolytica, the causative agent of amoebiasis, exhibit a dynamic membrane fusion and fission, in which lipids strongly participate; particularly during the overstated motility of the parasite to reach and attack the epithelia and ingest target cells. Synthesis and metabolism of lipids in this protozoan present remarkable difference with those performed by other eukaryotes. Here, we reviewed the current knowledge on lipids in E. histolytica. Trophozoites synthesize phosphatidylcholine and phosphatidylethanolamine by the Kennedy pathway; and sphingolipids, phosphatidylserine, and phosphatidylinositol, by processes similar to those used by other eukaryotes. However, trophozoites lack enzymes for cholesterol and fatty acids synthesis, which are scavenged from the host or culture medium by specific mechanisms. Cholesterol, a fundamental molecule for the expression of virulence, is transported from the medium into the trophozoites by EhNPC1 and EhNPC2 proteins. Inside cells, lipids are distributed by different pathways, including by the participation of the endosomal sorting complex required for transport (ESCRT), involved in vesicle fusion and fission. Cholesterol interacts with the phospholipid lysobisphosphatidic acid (LBPA) and EhADH, an ALIX family protein, also involved in phagocytosis. In this review, we summarize the known information on phospholipids synthesis and cholesterol transport as well as their metabolic pathways in E. histolytica; highlighting the mechanisms used by trophozoites to dispose lipids involved in the virulence processes.
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Affiliation(s)
- Silvia Castellanos-Castro
- College of Sciences and Humanities, Autonomous University of Mexico City, Mexico City, Mexico.,BioImage Analysis Unit, Pasteur Institute, Paris, France
| | - Jeni Bolaños
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies of the National Polytechnic Institute, Mexico City, Mexico.,Centro Multidisciplinario de Estudios en Biotecnología, FMVZ, Universidad Michoacana de San Nnicolás Hidalgo, Morelia, Mexico
| | - Esther Orozco
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies of the National Polytechnic Institute, Mexico City, Mexico
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19
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Zein AA, Kaur R, Hussein TOK, Graf GA, Lee JY. ABCG5/G8: a structural view to pathophysiology of the hepatobiliary cholesterol secretion. Biochem Soc Trans 2019; 47:1259-68. [PMID: 31654053 DOI: 10.1042/BST20190130] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 09/26/2019] [Accepted: 09/30/2019] [Indexed: 12/17/2022]
Abstract
The ABCG5/G8 heterodimer is the primary neutral sterol transporter in hepatobiliary and transintestinal cholesterol excretion. Inactivating mutations on either the ABCG5 or ABCG8 subunit cause Sitosterolemia, a rare genetic disorder. In 2016, a crystal structure of human ABCG5/G8 in an apo state showed the first structural information on ATP-binding cassette (ABC) sterol transporters and revealed several structural features that were observed for the first time. Over the past decade, several missense variants of ABCG5/G8 have been associated with non-Sitosterolemia lipid phenotypes. In this review, we summarize recent pathophysiological and structural findings of ABCG5/G8, interpret the structure-function relationship in disease-causing variants and describe the available evidence that allows us to build a mechanistic view of ABCG5/G8-mediated sterol transport.
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20
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Aghazadeh Y, Venugopal S, Martinez-Arguelles DB, Boisvert A, Blonder J, Papadopoulos V. Identification of Sec23ip, Part of 14-3-3γ Protein Network, as a Regulator of Acute Steroidogenesis in MA-10 Leydig Cells. Endocrinology 2020; 161:5686882. [PMID: 31875919 PMCID: PMC7007878 DOI: 10.1210/endocr/bqz036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 12/18/2019] [Indexed: 02/07/2023]
Abstract
Testosterone production occurs in the Leydig cells of the testes and is essential for virilization, development, reproduction, and quality of life. Although the steroidogenic proteins involved in cholesterol conversion to testosterone (T) are well characterized, the causes of reduced T during fetal, neonatal, and adult life remain uncertain. It is well established that normal cellular function is achieved through fine-tuning of multiple rather than single protein networks. Our objective was to use mass spectrometry (MS)-based proteomics to identify which cellular pathways, other than the steroidogenic machinery, influence testosterone production in MA-10 mouse tumor Leydig cells. The 14-3-3 family of scaffolds mediate protein-protein interactions facilitating the crosstalk between protein networks. We previously showed that in MA-10 cells, 14-3-3γ is a critical regulator of steroidogenesis. Therefore, identifying proteins that interact with 14-3-3γ during steroidogenesis could provide clues into the other networks involved. Using liquid chromatography (LC)-MS, we identified 688 proteins that interact with 14-3-3γ and thus potentially impact MA-10 cell steroidogenesis. The identified proteins belong to multiple protein networks, including endoplasmic reticulum-Golgi cargo sorting and vesicle biogenesis, micro ribonucleic acid-induced gene silencing, inflammation, and vesicle trafficking, to name a few. We found that silencing one of the candidates, Sec23ip, a protein known to be involved in vesicle trafficking, resulted in decreased steroidogenesis. We further showed that in Sec23ip-silenced MA-10 cells, cholesterol mobilization from the cytoplasmic membrane to mitochondria is impaired. Taken together these data suggest that Sec23ip is involved in cholesterol trafficking to supply cholesterol for acute steroidogenesis through its interactions with 14-3-3γ.
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Affiliation(s)
- Yasaman Aghazadeh
- The Research Institute of the McGill University Health Centre and the Department of Medicine, McGill University, 1001 Decarie Boulevard, Montreal, Quebec, Canada
- Present address: McEwen Stem Cell Center & Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Sathvika Venugopal
- The Research Institute of the McGill University Health Centre and the Department of Medicine, McGill University, 1001 Decarie Boulevard, Montreal, Quebec, Canada
| | - Daniel Benjamin Martinez-Arguelles
- The Research Institute of the McGill University Health Centre and the Department of Medicine, McGill University, 1001 Decarie Boulevard, Montreal, Quebec, Canada
| | - Annie Boisvert
- The Research Institute of the McGill University Health Centre and the Department of Medicine, McGill University, 1001 Decarie Boulevard, Montreal, Quebec, Canada
| | - Josip Blonder
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, sponsored by the National Cancer Institute, 8560 Progress Drive, Frederick, Maryland
| | - Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre and the Department of Medicine, McGill University, 1001 Decarie Boulevard, Montreal, Quebec, Canada
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, 1985 Zonal Ave, Los Angeles, California
- Correspondence: Vassilios Papadopoulos, Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, 1985 Zonal Ave, Los Angeles, California 90089, USA. E-mail:
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21
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Reiss AB, Arain HA, Kasselman LJ, Renna HA, Zhen J, Voloshyna I, DeLeon J, Carsons SE, Petri M. Human Lupus Plasma Pro-Atherogenic Effects on Cultured Macrophages Are Not Mitigated by Statin Therapy: A Mechanistic LAPS Substudy. ACTA ACUST UNITED AC 2019; 55:E514. [PMID: 31438615 DOI: 10.3390/medicina55090514] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/23/2019] [Accepted: 08/12/2019] [Indexed: 02/07/2023]
Abstract
Background and Objectives: Atherosclerotic cardiovascular disease (CVD) remains a major cause of morbidity and mortality in persons with systemic lupus erythematosus (SLE, lupus). Atherosclerosis, which involves interplay between cholesterol metabolism and cellular inflammatory pathways, is primarily treated with statins since statins have lipid-lowering and anti-inflammatory properties. The Lupus Atherosclerosis Prevention Study (LAPS) was designed to investigate the efficacy of statins against CVD in SLE patients. LAPS demonstrated that 2 years of atorvastatin administration did not reduce atherosclerosis progression in lupus patients. In this LAPs substudy, we use cultured macrophages to explore the atherogenic properties of plasma from LAPS subjects to explain the mechanistic rationale for the inability of statins to reduce CVD in lupus. Materials and Methods: THP-1 differentiated macrophages were treated for 18 h with 10% SLE patient plasma obtained pre- and post-atorvastatin therapy or placebo. Gene expression of the following cholesterol transport genes was measured by qRT-PCR. For efflux—ATP binding cassette transporter (ABC)A1 and ABCG1, 27-hydroxylase, peroxisome proliferator-activated receptor (PPAR)γ, and liver X receptor (LXR)α; and for influx—cluster of differentiation 36 (CD36) and scavenger receptor (ScR)A1. Results: Macrophages exposed to plasma from both statin-treated and placebo-treated groups showed a significant decrease in cholesterol efflux proteins ATP binding cassette (ABC) transporters A1 and ABCG1, an increase in 27-hydroxylase, an increase in the LDL receptor and a decrease in intracellular free cholesterol. No change in influx receptors ScRA1 and CD36, nor nuclear proteins LXRα and PPARγ was observed. Conclusions: Statins do not normalize pro-atherogenic changes induced by lupus and these changes continue to worsen over time. This study provides mechanistic insight into LAPS findings by demonstrating that statins are overall ineffective in altering the balance of cholesterol transport gene expression in human macrophages. Furthermore, our study suggests that statins as a CVD treatment may not be useful in attenuating lipid overload in the SLE environment.
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22
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Campos A, Burgos-Ravanal R, González MF, Huilcaman R, Lobos González L, Quest AFG. Cell Intrinsic and Extrinsic Mechanisms of Caveolin-1-Enhanced Metastasis. Biomolecules 2019; 9:E314. [PMID: 31362353 DOI: 10.3390/biom9080314] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/17/2019] [Accepted: 07/25/2019] [Indexed: 12/19/2022] Open
Abstract
Caveolin-1 (CAV1) is a scaffolding protein with a controversial role in cancer. This review will initially discuss earlier studies focused on the role as a tumor suppressor before elaborating subsequently on those relating to function of the protein as a promoter of metastasis. Different mechanisms are summarized illustrating how CAV1 promotes such traits upon expression in cancer cells (intrinsic mechanisms). More recently, it has become apparent that CAV1 is also a secreted protein that can be included into exosomes where it plays a significant role in determining cargo composition. Thus, we will also discuss how CAV1 containing exosomes from metastatic cells promote malignant traits in more benign recipient cells (extrinsic mechanisms). This ability appears, at least in part, attributable to the transfer of specific cargos present due to CAV1 rather than the transfer of CAV1 itself. The evolution of how our perception of CAV1 function has changed since its discovery is summarized graphically in a time line figure.
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23
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Abstract
Low-density lipoprotein particles are taken up by cells and delivered to the lysosome where their cholesterol esters are cleaved off by acid lipase. The released, free cholesterol is then exported from lysosomes for cellular needs or storage. This article summarizes recent advances in our understanding of the molecular basis of cholesterol export from lysosomes. Cholesterol export requires NPC intracellular cholesterol transporter 1 (NPC1) and NPC2, genetic mutations of which can cause Niemann-Pick type C disease, a disorder characterized by massive lysosomal accumulation of cholesterol and glycosphingolipids. Analysis of the NPC1 and NPC2 structures and biochemical properties, together with new structures of the related Patched (PTCH) protein, provides new clues to the mechanisms by which NPC proteins may function.
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Affiliation(s)
- Suzanne R Pfeffer
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305-5307.
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24
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Abstract
Delivery of low-density lipoprotein-derived cholesterol to the endoplasmic reticulum (ER) is essential for cholesterol homeostasis, yet the mechanism of this transport has largely remained elusive. Two recent reports shed some light on this process, uncovering a role for Niemann Pick type-C1 protein (NPC1) in the formation of membrane contact sites (MCS) between late endosomes (LE)/lysosomes (Lys) and the ER. Both studies identified a loss of MCS in cells lacking functional NPC1, where cholesterol accumulates in late endocytic organelles. Remarkably, and taking different approaches, both studies have made a striking observation that expansion of LE/Lys-ER MCS can rescue the cholesterol accumulation phenotype in NPC1 mutant or deficient cells. In both cases, the cholesterol was shown to be transported to the ER, demonstrating the importance of ER-LE/Lys contact sites in the direct transport of low-density lipoprotein-derived cholesterol to the ER.
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Affiliation(s)
- Carlos Enrich
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Spain
- Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - Carles Rentero
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Spain
- Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - Thomas Grewal
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia
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25
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Zhang Y, Bulkley DP, Xin Y, Roberts KJ, Asarnow DE, Sharma A, Myers BR, Cho W, Cheng Y, Beachy PA. Structural Basis for Cholesterol Transport-like Activity of the Hedgehog Receptor Patched. Cell 2018; 175:1352-1364.e14. [PMID: 30415841 DOI: 10.1016/j.cell.2018.10.026] [Citation(s) in RCA: 162] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/01/2018] [Accepted: 10/10/2018] [Indexed: 12/31/2022]
Abstract
Hedgehog protein signals mediate tissue patterning and maintenance by binding to and inactivating their common receptor Patched, a 12-transmembrane protein that otherwise would suppress the activity of the 7-transmembrane protein Smoothened. Loss of Patched function, the most common cause of basal cell carcinoma, permits unregulated activation of Smoothened and of the Hedgehog pathway. A cryo-EM structure of the Patched protein reveals striking transmembrane domain similarities to prokaryotic RND transporters. A central hydrophobic conduit with cholesterol-like contents courses through the extracellular domain and resembles that used by other RND proteins to transport substrates, suggesting Patched activity in cholesterol transport. Cholesterol activity in the inner leaflet of the plasma membrane is reduced by PTCH1 expression but rapidly restored by Hedgehog stimulation, suggesting that PTCH1 regulates Smoothened by controlling cholesterol availability.
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Liao Y, Wei J, Wang J, Shi X, Luo J, Song BL. The non-canonical NF-κB pathway promotes NPC2 expression and regulates intracellular cholesterol trafficking. Sci China Life Sci 2018; 61:1222-32. [PMID: 30091016 DOI: 10.1007/s11427-018-9339-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/14/2018] [Indexed: 02/06/2023]
Abstract
Niemann-Pick type C2 (NPC2) is a lysosome luminal protein that functions in concert with NPC1 to mediate egress of low-density lipoprotein-derived cholesterol from lysosome. The nuclear factor kappa B subunit 2 (NF-κB2) protein is a component of NF-κB transcription factor complex critically implicated in immune and inflammatory responses. Here, we report that NF-κB2 regulates intracellular cholesterol transport by controlling NPC2 expression. RNAi-mediated disruption of NF-κB2, as well as other signaling members of the non-canonical NF-κB pathway, caused intracellular cholesterol accumulation. Blockage of the non-canonical NF-κB pathway suppressed NPC2 expression, whereas Lymphotoxin β receptor (LTβR) activation or Baff receptor (BaffR) stimulation up-regulated the mRNA abundance and protein level of NPC2. Further, NF-κB2 activated NPC2 transcription through direct binding to its promoter region. We also observed cholesterol accumulation in NF-κB2-deficient zebrafish embryo and NF-κB2 mutant mice. Collectively, these data identify a regulatory role for the non-canonical NF-κB pathway in intracellular cholesterol trafficking and suggest a link between cholesterol transport and immune system.
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Trinh MN, Brown MS, Seemann J, Goldstein JL, Lu F. Lysosomal cholesterol export reconstituted from fragments of Niemann-Pick C1. eLife 2018; 7:e38564. [PMID: 30047864 PMCID: PMC6062155 DOI: 10.7554/elife.38564] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 07/17/2018] [Indexed: 12/25/2022] Open
Abstract
Niemann-Pick C1 (NPC1) is a polytopic membrane protein with 13 transmembrane helices that exports LDL-derived cholesterol from lysosomes by carrying it through the 80 Å glycocalyx and the 40 Å lipid bilayer. Transport begins when cholesterol binds to the N-terminal domain (NTD) of NPC1, which projects to the surface of the glycocalyx. Here, we reconstitute cholesterol transport by expressing the NTD as a fragment separate from the remaining portion of NPC1. When co-expressed, the two NPC1 fragments reconstitute cholesterol transport, indicating that the NTD has the flexibility to interact with the remaining parts of NPC1 even when not covalently linked. We also show that cholesterol can be transferred from the NTD of one full-length NPC1 to another NPC1 molecule that lacks the NTD. These data support the hypothesis that cholesterol is transported through interactions between two or more NPC1 molecules.
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Affiliation(s)
- Michael Nguyen Trinh
- Departments of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasUnited States
| | - Michael S Brown
- Departments of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasUnited States
| | - Joachim Seemann
- Cell BiologyUniversity of Texas Southwestern Medical CenterDallasUnited States
| | - Joseph L Goldstein
- Departments of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasUnited States
| | - Feiran Lu
- Departments of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasUnited States
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Zhao K, Ridgway ND. Oxysterol-Binding Protein-Related Protein 1L Regulates Cholesterol Egress from the Endo-Lysosomal System. Cell Rep 2018; 19:1807-1818. [PMID: 28564600 DOI: 10.1016/j.celrep.2017.05.028] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 04/13/2017] [Accepted: 05/08/2017] [Indexed: 02/02/2023] Open
Abstract
Lipoprotein cholesterol is delivered to the limiting membrane of late endosomes/lysosomes (LELs) by Niemann-Pick C1 (NPC1). However, the mechanism of cholesterol transport from LELs to the endoplasmic reticulum (ER) is poorly characterized. We report that oxysterol-binding protein-related protein 1L (ORP1L) is necessary for this stage of cholesterol export. CRISPR-mediated knockout of ORP1L in HeLa and HEK293 cells reduced esterification of cholesterol to the level in NPC1 knockout cells, and it increased the expression of sterol-regulated genes and de novo cholesterol synthesis, indicative of a block in cholesterol transport to the ER. In the absence of this transport pathway, cholesterol-enriched LELs accumulated in the Golgi/perinuclear region. Cholesterol delivery to the ER required the sterol-, phosphatidylinositol 4-phosphate-, and vesicle-associated membrane protein-associated protein (VAP)-binding activities of ORP1L, as well as NPC1 expression. These results suggest that ORP1L-dependent membrane contacts between LELs and the ER coordinate cholesterol transfer with the retrograde movement of endo-lysosomal vesicles.
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Affiliation(s)
- Kexin Zhao
- Departments of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Box 15000, Halifax, NS B3H 4R2, Canada
| | - Neale D Ridgway
- Departments of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Box 15000, Halifax, NS B3H 4R2, Canada.
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Abstract
The picture of HDL cholesterol (HDL-C) as the "good" cholesterol has eroded. This is even more surprising because there exists strong evidence that HDL-C is associated with cardiovascular disease (CVD) in the general population as well as in patients with impairment of kidney function and/or progression of CKD. However, drugs that dramatically increase HDL-C have mostly failed to decrease CVD events. Furthermore, genetic studies took the same line, as genetic variants that have a pronounced influence on HDL-C concentrations did not show an association with cardiovascular risk. For many, this was not surprising, given that an HDL particle is highly complex and carries >80 proteins and several hundred lipid species. Simply measuring cholesterol might not reflect the variety of biologic effects of heterogeneous HDL particles. Therefore, functional studies and the involvement of HDL components in the reverse cholesterol transport, including the cholesterol efflux capacity, have become a further focus of study during recent years. As also observed for other aspects, CKD populations behave differently compared with non-CKD populations. Although clear disturbances have been observed for the "functionality" of HDL particles in patients with CKD, this did not necessarily translate into clear-cut associations with outcomes.
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Affiliation(s)
- Florian Kronenberg
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
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30
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Owen DR, Fan J, Campioli E, Venugopal S, Midzak A, Daly E, Harlay A, Issop L, Libri V, Kalogiannopoulou D, Oliver E, Gallego-Colon E, Colasanti A, Huson L, Rabiner EA, Suppiah P, Essagian C, Matthews PM, Papadopoulos V. TSPO mutations in rats and a human polymorphism impair the rate of steroid synthesis. Biochem J 2017; 474:3985-99. [PMID: 29074640 DOI: 10.1042/BCJ20170648] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 10/20/2017] [Accepted: 10/25/2017] [Indexed: 01/08/2023]
Abstract
The 18 kDa translocator protein (TSPO) is a ubiquitous conserved outer mitochondrial membrane protein implicated in numerous cell and tissue functions, including steroid hormone biosynthesis, respiration, cell proliferation, and apoptosis. TSPO binds with high affinity to cholesterol and numerous compounds, is expressed at high levels in steroid-synthesizing tissues, and mediates cholesterol import into mitochondria, which is the rate-limiting step in steroid formation. In humans, the rs6971 polymorphism on the TSPO gene leads to an amino acid substitution in the fifth transmembrane loop of the protein, which is where the cholesterol-binding domain of TSPO is located, and this polymorphism has been associated with anxiety-related disorders. However, recent knockout mouse models have provided inconsistent conclusions of whether TSPO is directly involved in steroid synthesis. In this report, we show that TSPO deletion mutations in rat and its corresponding rs6971 polymorphism in humans alter adrenocorticotropic hormone-induced plasma corticosteroid concentrations. Rat tissues examined show increased cholesteryl ester accumulation, and neurosteroid formation was undetectable in homozygous rats. These results also support a role for TSPO ligands in diseases with steroid-dependent stress and anxiety elements.
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31
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Li X, Lu F, Trinh MN, Schmiege P, Seemann J, Wang J, Blobel G. 3.3 Å structure of Niemann-Pick C1 protein reveals insights into the function of the C-terminal luminal domain in cholesterol transport. Proc Natl Acad Sci U S A 2017; 114:9116-21. [PMID: 28784760 DOI: 10.1073/pnas.1711716114] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Niemann-Pick C1 (NPC1) and NPC2 proteins are indispensable for the export of LDL-derived cholesterol from late endosomes. Mutations in these proteins result in Niemann-Pick type C disease, a lysosomal storage disease. Despite recent reports of the NPC1 structure depicting its overall architecture, the function of its C-terminal luminal domain (CTD) remains poorly understood even though 45% of NPC disease-causing mutations are in this domain. Here, we report a crystal structure at 3.3 Å resolution of NPC1* (residues 314-1,278), which-in contrast to previous lower resolution structures-features the entire CTD well resolved. Notably, all eight cysteines of the CTD form four disulfide bonds, one of which (C909-C914) enforces a specific loop that in turn mediates an interaction with a loop of the N-terminal domain (NTD). Importantly, this loop and its interaction with the NTD were not observed in any previous structures due to the lower resolution. Our mutagenesis experiments highlight the physiological relevance of the CTD-NTD interaction, which might function to keep the NTD in the proper orientation for receiving cholesterol from NPC2. Additionally, this structure allows us to more precisely map all of the disease-causing mutations, allowing future molecular insights into the pathogenesis of NPC disease.
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Westerterp M, Gautier EL, Ganda A, Molusky MM, Wang W, Fotakis P, Wang N, Randolph GJ, D'Agati VD, Yvan-Charvet L, Tall AR. Cholesterol Accumulation in Dendritic Cells Links the Inflammasome to Acquired Immunity. Cell Metab 2017; 25:1294-1304.e6. [PMID: 28479366 PMCID: PMC5514787 DOI: 10.1016/j.cmet.2017.04.005] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 11/04/2016] [Accepted: 04/06/2017] [Indexed: 11/18/2022]
Abstract
Autoimmune diseases such as systemic lupus erythematosus (SLE) are associated with increased cardiovascular disease and reduced plasma high-density lipoprotein (HDL) levels. HDL mediates cholesterol efflux from immune cells via the ATP binding cassette transporters A1 and G1 (ABCA1/G1). The significance of impaired cholesterol efflux pathways in autoimmunity is unknown. We observed that Abca1/g1-deficient mice develop enlarged lymph nodes (LNs) and glomerulonephritis suggestive of SLE. This lupus-like phenotype was recapitulated in mice with knockouts of Abca1/g1 in dendritic cells (DCs), but not in macrophages or T cells. DC-Abca1/g1 deficiency increased LN and splenic CD11b+ DCs, which displayed cholesterol accumulation and inflammasome activation, increased cell surface levels of the granulocyte macrophage-colony stimulating factor receptor, and enhanced inflammatory cytokine secretion. Consequently, DC-Abca1/g1 deficiency enhanced T cell activation and Th1 and Th17 cell polarization. Nlrp3 inflammasome deficiency diminished the enlarged LNs and enhanced Th1 cell polarization. These findings identify an essential role of DC cholesterol efflux pathways in maintaining immune tolerance.
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Affiliation(s)
- Marit Westerterp
- Division of Molecular Medicine, Department of Medicine, Columbia University, 630 West 168 Street, P&S 8-401, New York, NY 10032, USA; Department of Pediatrics, Section Molecular Genetics, University Medical Center Groningen, University of Groningen, 9713 AV Groningen, the Netherlands.
| | - Emmanuel L Gautier
- Department of Pathology and Immunology, Washington University, St. Louis, MO 63110, USA
| | - Anjali Ganda
- Division of Molecular Medicine, Department of Medicine, Columbia University, 630 West 168 Street, P&S 8-401, New York, NY 10032, USA; Division of Nephrology, Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Matthew M Molusky
- Division of Molecular Medicine, Department of Medicine, Columbia University, 630 West 168 Street, P&S 8-401, New York, NY 10032, USA
| | - Wei Wang
- Division of Molecular Medicine, Department of Medicine, Columbia University, 630 West 168 Street, P&S 8-401, New York, NY 10032, USA
| | - Panagiotis Fotakis
- Division of Molecular Medicine, Department of Medicine, Columbia University, 630 West 168 Street, P&S 8-401, New York, NY 10032, USA
| | - Nan Wang
- Division of Molecular Medicine, Department of Medicine, Columbia University, 630 West 168 Street, P&S 8-401, New York, NY 10032, USA
| | - Gwendalyn J Randolph
- Department of Pathology and Immunology, Washington University, St. Louis, MO 63110, USA
| | - Vivette D D'Agati
- Department of Pathology, Columbia University, New York, NY 10032, USA
| | - Laurent Yvan-Charvet
- Division of Molecular Medicine, Department of Medicine, Columbia University, 630 West 168 Street, P&S 8-401, New York, NY 10032, USA
| | - Alan R Tall
- Division of Molecular Medicine, Department of Medicine, Columbia University, 630 West 168 Street, P&S 8-401, New York, NY 10032, USA
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Infante RE, Radhakrishnan A. Continuous transport of a small fraction of plasma membrane cholesterol to endoplasmic reticulum regulates total cellular cholesterol. eLife 2017; 6. [PMID: 28414269 PMCID: PMC5433840 DOI: 10.7554/elife.25466] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [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: 01/25/2017] [Accepted: 04/16/2017] [Indexed: 01/15/2023] Open
Abstract
Cells employ regulated transport mechanisms to ensure that their plasma membranes (PMs) are optimally supplied with cholesterol derived from uptake of low-density lipoproteins (LDL) and synthesis. To date, all inhibitors of cholesterol transport block steps in lysosomes, limiting our understanding of post-lysosomal transport steps. Here, we establish the cholesterol-binding domain 4 of anthrolysin O (ALOD4) as a reversible inhibitor of cholesterol transport from PM to endoplasmic reticulum (ER). Using ALOD4, we: (1) deplete ER cholesterol without altering PM or overall cellular cholesterol levels; (2) demonstrate that LDL-derived cholesterol travels from lysosomes first to PM to meet cholesterol needs, and subsequently from PM to regulatory domains of ER to suppress activation of SREBPs, halting cholesterol uptake and synthesis; and (3) determine that continuous PM-to-ER cholesterol transport allows ER to constantly monitor PM cholesterol levels, and respond rapidly to small declines in cellular cholesterol by activating SREBPs, increasing cholesterol uptake and synthesis.
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Affiliation(s)
- Rodney Elwood Infante
- Departments of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States.,Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Arun Radhakrishnan
- Departments of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
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Trinh MN, Lu F, Li X, Das A, Liang Q, De Brabander JK, Brown MS, Goldstein JL. Triazoles inhibit cholesterol export from lysosomes by binding to NPC1. Proc Natl Acad Sci U S A 2017; 114:89-94. [PMID: 27994139 DOI: 10.1073/pnas.1619571114] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Niemann-Pick C1 (NPC1), a membrane protein of lysosomes, is required for the export of cholesterol derived from receptor-mediated endocytosis of LDL. Lysosomal cholesterol export is reportedly inhibited by itraconazole, a triazole that is used as an antifungal drug [Xu et al. (2010) Proc Natl Acad Sci USA 107:4764-4769]. Here we show that posaconazole, another triazole, also blocks cholesterol export from lysosomes. We prepared P-X, a photoactivatable cross-linking derivative of posaconazole. P-X cross-linked to NPC1 when added to intact cells. Cross-linking was inhibited by itraconazole but not by ketoconazole, an imidazole that does not block cholesterol export. Cross-linking of P-X was also blocked by U18666A, a compound that has been shown to bind to NPC1 and inhibit cholesterol export. P-X also cross-linked to purified NPC1 that was incorporated into lipid bilayer nanodiscs. In this in vitro system, cross-linking of P-X was inhibited by itraconazole, but not by U18666A. P-X cross-linking was not prevented by deletion of the N-terminal domain of NPC1, which contains the initial binding site for cholesterol. In contrast, P-X cross-linking was reduced when NPC1 contained a point mutation (P691S) in its putative sterol-sensing domain. We hypothesize that the sterol-sensing domain has a binding site that can accommodate structurally different ligands.
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35
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Narasimhulu CA, Selvarajan K, Burge KY, Litvinov D, Sengupta B, Parthasarathy S. Water-Soluble Components of Sesame Oil Reduce Inflammation and Atherosclerosis. J Med Food 2016; 19:629-37. [PMID: 27348418 DOI: 10.1089/jmf.2015.0154] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Atherosclerosis, a major form of cardiovascular disease, is now recognized as a chronic inflammatory disease. Nonpharmacological means of treating chronic diseases have gained attention recently. We previously reported that sesame oil aqueous extract (SOAE) has anti-inflammatory properties, both in vitro and in vivo. In this study, we have investigated the antiatherosclerotic properties of SOAE, and the mechanisms, through genes and inflammatory markers, by which SOAE might modulate atherosclerosis. Low-density lipoprotein receptor (LDL-R) knockout female mice were fed with either a high-fat (HF) diet or an HF diet supplemented with SOAE. Plasma lipids and atherosclerotic lesions were quantified after 3 months of feeding. Plasma samples were used for global cytokine array. RNA was extracted from both liver tissue and the aorta, and used for gene analysis. The high-fat diet supplemented with SOAE significantly reduced atherosclerotic lesions, plasma cholesterol, and LDL cholesterol levels in LDL-R(-/-) mice. Plasma inflammatory cytokines were reduced in the SOAE diet-fed animals, but not significantly, demonstrating potential anti-inflammatory properties of SOAE. Gene analysis showed the HF diet supplemented with SOAE reduced gene expression involved in inflammation and induced genes involved in cholesterol metabolism and reverse cholesterol transport, an anti-inflammatory process. Our studies suggest that a SOAE-enriched diet could be an effective nonpharmacological treatment for atherosclerosis by controlling inflammation and regulating lipid metabolism.
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Affiliation(s)
| | - Krithika Selvarajan
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida , Orlando, Florida, USA
| | - Kathryn Young Burge
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida , Orlando, Florida, USA
| | - Dmitry Litvinov
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida , Orlando, Florida, USA
| | - Bhaswati Sengupta
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida , Orlando, Florida, USA
| | - Sampath Parthasarathy
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida , Orlando, Florida, USA
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Voloshyna I, Teboul I, Littlefield MJ, Siegart NM, Turi GK, Fazzari MJ, Carsons SE, DeLeon J, Reiss AB. Resveratrol counters systemic lupus erythematosus-associated atherogenicity by normalizing cholesterol efflux. Exp Biol Med (Maywood) 2016; 241:1611-9. [PMID: 27190277 DOI: 10.1177/1535370216647181] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 04/01/2016] [Indexed: 11/16/2022] Open
Abstract
Resveratrol is a bioactive molecule used in dietary supplements and herbal medicines and consumed worldwide. Numerous investigations by our group and others have indicated cardioprotective and anti-inflammatory properties of resveratrol. The present study explored potential atheroprotective actions of resveratrol on cholesterol efflux in cultured human macrophages exposed to plasma from systemic lupus erythematosus (SLE) patients. These results were confirmed in ApoE(-/-)Fas(-/-) double knockout mice, displaying a lupus profile with accelerated atherosclerosis. Resveratrol treatment attenuated atherosclerosis in these mice. THP-1 human macrophages were exposed to 10% pooled or individual plasma from patients who met diagnostic criteria for SLE. Expression of multiple proteins involved in reverse cholesterol transport (ABCA1, ABCG1, SR-B1, and cytochrome P450 27-hydroxylase) was assessed using QRT-PCR and Western blotting techniques. Ten-week-old ApoE(-/-)Fas(-/-) double knockout mice (n = 30) were randomly divided into two equal groups of 15, one of which received 0.01% resveratrol for 10 consecutive weeks. Atherosclerosis progression was evaluated in murine aortas. Bone marrow-derived macrophages (BMDM) were cultured and expression of cholesterol efflux proteins was analyzed in each group of mice. Our data indicate that inhibition of cholesterol efflux by lupus plasma in THP-1 human macrophages is rescued by resveratrol. Similarly, administration of resveratrol in a lupus-like murine model reduces plaque formation in vivo and augments cholesterol efflux in BMDM. This study presents evidence for a beneficial role of resveratrol in atherosclerosis in the specific setting of SLE. Therefore, resveratrol may merit investigation as an additional resource available to reduce lipid deposition and atherosclerosis in humans, especially in such vulnerable populations as lupus patients.
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Affiliation(s)
- Iryna Voloshyna
- Department of Medicine and Winthrop Research Institute, Winthrop University Hospital, Mineola, NY 11501, USA
| | - Isaac Teboul
- Department of Medicine and Winthrop Research Institute, Winthrop University Hospital, Mineola, NY 11501, USA
| | - Michael J Littlefield
- Department of Medicine and Winthrop Research Institute, Winthrop University Hospital, Mineola, NY 11501, USA
| | - Nicolle M Siegart
- Department of Medicine and Winthrop Research Institute, Winthrop University Hospital, Mineola, NY 11501, USA
| | - George K Turi
- Department of Medicine and Winthrop Research Institute, Winthrop University Hospital, Mineola, NY 11501, USA
| | - Melissa J Fazzari
- Department of Medicine and Winthrop Research Institute, Winthrop University Hospital, Mineola, NY 11501, USA
| | - Steven E Carsons
- Department of Medicine and Winthrop Research Institute, Winthrop University Hospital, Mineola, NY 11501, USA
| | - Joshua DeLeon
- Department of Medicine and Winthrop Research Institute, Winthrop University Hospital, Mineola, NY 11501, USA
| | - Allison B Reiss
- Department of Medicine and Winthrop Research Institute, Winthrop University Hospital, Mineola, NY 11501, USA
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37
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Zhao Y, Ren J, Harlos K, Stuart DI. Structure of glycosylated NPC1 luminal domain C reveals insights into NPC2 and Ebola virus interactions. FEBS Lett 2016; 590:605-12. [PMID: 26846330 PMCID: PMC4819692 DOI: 10.1002/1873-3468.12089] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [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: 01/19/2016] [Revised: 01/27/2016] [Accepted: 01/28/2016] [Indexed: 01/14/2023]
Abstract
Niemann‐pick type C1 (NPC1) is an endo/lysosomal membrane protein involved in intracellular cholesterol trafficking, and its luminal domain C is an essential endosomal receptor for Ebola and Marburg viruses. We have determined the crystal structure of glycosylated NPC1 luminal domain C and find all seven possible sites are glycosylated. Mapping the disease mutations onto the glycosylated structure reveals a potential binding face for NPC2. Knowledge‐based docking of NPC1 onto Ebola viral glycoprotein and sequence analysis of filovirus susceptible and refractory species reveals four critical residues, H418, Q421, F502 and F504, some or all of which are likely responsible for the species‐specific susceptibility to the virus infection.
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Affiliation(s)
- Yuguang Zhao
- Division of Structural Biology, University of Oxford, Headington, Oxford, UK
| | - Jingshan Ren
- Division of Structural Biology, University of Oxford, Headington, Oxford, UK
| | - Karl Harlos
- Division of Structural Biology, University of Oxford, Headington, Oxford, UK
| | - David I Stuart
- Division of Structural Biology, University of Oxford, Headington, Oxford, UK.,Diamond Light Source Ltd, Didcot, UK
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38
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Midzak A, Papadopoulos V. Adrenal Mitochondria and Steroidogenesis: From Individual Proteins to Functional Protein Assemblies. Front Endocrinol (Lausanne) 2016; 7:106. [PMID: 27524977 PMCID: PMC4965458 DOI: 10.3389/fendo.2016.00106] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/18/2016] [Indexed: 12/13/2022] Open
Abstract
The adrenal cortex is critical for physiological function as the central site of glucocorticoid and mineralocorticoid synthesis. It possesses a great degree of specialized compartmentalization at multiple hierarchical levels, ranging from the tissue down to the molecular levels. In this paper, we discuss this functionalization, beginning with the tissue zonation of the adrenal cortex and how this impacts steroidogenic output. We then discuss the cellular biology of steroidogenesis, placing special emphasis on the mitochondria. Mitochondria are classically known as the "powerhouses of the cell" for their central role in respiratory adenosine triphosphate synthesis, and attention is given to mitochondrial electron transport, in both the context of mitochondrial respiration and mitochondrial steroid metabolism. Building on work demonstrating functional assembly of large protein complexes in respiration, we further review research demonstrating a role for multimeric protein complexes in mitochondrial cholesterol transport, steroidogenesis, and mitochondria-endoplasmic reticulum contact. We aim to highlight with this review the shift in steroidogenic cell biology from a focus on the actions of individual proteins in isolation to the actions of protein assemblies working together to execute cellular functions.
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Affiliation(s)
- Andrew Midzak
- Research Institute of the McGill University, Montreal, QC, Canada
- *Correspondence: Andrew Midzak, ; Vassilios Papadopoulos,
| | - Vassilios Papadopoulos
- Research Institute of the McGill University, Montreal, QC, Canada
- Department of Biochemistry, McGill University, Montreal, QC, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
- *Correspondence: Andrew Midzak, ; Vassilios Papadopoulos,
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Lu F, Liang Q, Abi-Mosleh L, Das A, De Brabander JK, Goldstein JL, Brown MS. Identification of NPC1 as the target of U18666A, an inhibitor of lysosomal cholesterol export and Ebola infection. eLife 2015; 4. [PMID: 26646182 PMCID: PMC4718804 DOI: 10.7554/elife.12177] [Citation(s) in RCA: 226] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/08/2015] [Indexed: 12/19/2022] Open
Abstract
Niemann-Pick C1 (NPC1) is a lysosomal membrane protein that exports cholesterol derived from receptor-mediated uptake of LDL, and it also mediates cellular entry of Ebola virus. Cholesterol export is inhibited by nanomolar concentrations of U18666A, a cationic sterol. To identify the target of U18666A, we synthesized U-X, a U18666A derivative with a benzophenone that permits ultraviolet-induced crosslinking. When added to CHO cells, U-X crosslinked to NPC1. Crosslinking was blocked by U18666A derivatives that block cholesterol export, but not derivatives lacking blocking activity. Crosslinking was prevented by point mutation in the sterol-sensing domain (SSD) of NPC1, but not by point mutation in the N-terminal domain (NTD). These data suggest that the SSD contains a U18666A-inhibitable site required for cholesterol export distinct from the cholesterol-binding site in the NTD. Inasmuch as inhibition of Ebola requires 100-fold higher concentrations of U18666A, the high affinity U16888A-binding site is likely not required for virus entry. DOI:http://dx.doi.org/10.7554/eLife.12177.001 Cholesterol is a type of fat molecule and is a vital component of animal cell membranes. It is taken up into cells within particles called low density lipoproteins (LDLs) that are then digested in cell compartments known as lysosomes to release the cholesterol. Then, the cholesterol leaves the lysosome with the help of a transport protein called NPC1. Mutations in the gene that encodes NPC1 lead to the accumulation of cholesterol in lysosomes; this can cause a devastating illness that affects the brain, liver and other organs. The NPC1 protein also plays a crucial role in allowing Ebola viruses to infect animal cells and multiply. U18666A is a drug that blocks the movement of cholesterol out of lysosomes and also inhibits Ebola virus infections, but it was not known what components it targets in cells. Lu et al. used a technique called ultraviolet-induced crosslinking to identify the proteins that U18666A can bind to. The experiments show that U18666A can directly bind to a site that is within a section of the NPC1 protein called the sterol-sensing domain. The binding of U18666A to this site blocks the movement of cholesterol out of lysosomes. Lu et al.’s findings indicate that the sterol-sensing domain of NPC1 plays a crucial role in cholesterol’s export from lysosomes. A future challenge is to use structural biology techniques (such as X-ray crystallography or cryo-electron microscope tomography) to understand the three-dimensional structure of NPC1. DOI:http://dx.doi.org/10.7554/eLife.12177.002
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Affiliation(s)
- Feiran Lu
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Qiren Liang
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, United States
| | - Lina Abi-Mosleh
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Akash Das
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Jef K De Brabander
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joseph L Goldstein
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Michael S Brown
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
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Abstract
Atherosclerosis, a major form of cardiovascular disease, has now been recognized as a chronic inflammatory disease. Nonpharmacological means of treating chronic diseases have gained attention recently. We previously reported that sesame oil has anti-atherosclerotic properties. In this study, we have determined the mechanisms by which sesame oil might modulate atherosclerosis by identifying genes and inflammatory markers. Low-density lipoprotein receptor knockout (LDLR(-/-)) female mice were fed with either an atherogenic diet or an atherogenic diet reformulated with sesame oil (sesame oil diet). Plasma lipids and atherosclerotic lesions were quantified after 3 months of feeding. Plasma samples were used for cytokine analysis. RNA was extracted from the liver tissue and used for global gene arrays. The sesame oil diet significantly reduced atherosclerotic lesions, plasma cholesterol, triglyceride, and LDL cholesterol levels in LDLR(-/-) mice. Plasma inflammatory cytokines, such as MCP-1, RANTES, IL-1α, IL-6, and CXCL-16, were significantly reduced, demonstrating an anti-inflammatory property of sesame oil. Gene array analysis showed that sesame oil induced many genes, including ABCA1, ABCA2, APOE, LCAT, and CYP7A1, which are involved in cholesterol metabolism and reverse cholesterol transport. In conclusion, our studies suggest that a sesame oil-enriched diet could be an effective nonpharmacological treatment for atherosclerosis by controlling inflammation and regulating lipid metabolism.
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Akopian D, Kawashima RL, Medh JD. Phosphatidylcholine-Mediated Aqueous Diffusion of Cellular Cholesterol Down-Regulates the ABCA1 Transporter in Human Skin Fibroblasts. ACTA ACUST UNITED AC 2015; 5:214-224. [PMID: 26042209 PMCID: PMC4450801 DOI: 10.9734/ijbcrr/2015/14058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [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] [Indexed: 12/15/2022]
Abstract
ATP-binding cassette protein A1 (ABCA1) is a cholesterol transporter that contributes to the active transport/removal of excess cellular cholesterol. ABCA1 expression is up-regulated when cells accumulate cholesterol. AIMS The purpose of this study was to determine any correlation between extracellular phospholipid levels and ABCA1 expression and function. METHODOLOGY Human foreskin fibroblasts were incubated with cholesterol alone or cholesterol and phosphatidylcholine. Total RNA was isolated and subjected to end-point RT-PCR to compare ABCA1 transcript levels. Cell lysates were subjected to Western blot analysis to compare ABCA1 protein levels. Cells were loaded with radiolabeled cholesterol and cellular cholesterol efflux was measured in the presence and absence of apoE, a cholesterol acceptor. ApoE-dependent efflux was calculated as a measure of ABCA1-mediated efflux. RESULTS Here we show that incubation of cholesterol-loaded human skin fibroblasts with L-α-phosphatidylcholine (PC) decreases ABCA1 mRNA and protein levels by 93% and 57%, respectively, compared to cells loaded with cholesterol alone. Similarly, PC treatment results in a 25% reduction in ABCG1 mRNA levels compared to cells treated with cholesterol alone, but there is no change in SR-BI transcript levels. Subsequent incubation of phospholipid-treated cells with a cholesterol acceptor such as apoE for 24 hours shows a 65% reduction in ABCA1-mediated cholesterol efflux compared to efflux in cells not treated with PC. During the lipid treatment itself, there is a 2.7-fold greater loss of cholesterol from PC treated cells compared to cells treated with cholesterol alone. Measurement of cholesterol in cellular lipid extracts reveals that cells incubated in the presence of phosphatidylcholine are significantly depleted of cholesterol having only 20% of the cholesterol compared to cells loaded with cholesterol alone. CONCLUSION Thus, phosphatidylcholine facilitates removal of cellular cholesterol, thereby negating the cholesterol-dependent induction of ABCA1 message, protein and function.
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Affiliation(s)
- David Akopian
- Department of Chemistry and Biochemistry, California State University Northridge Northridge CA 91330-8262, USA
| | - Ryoko L Kawashima
- Department of Chemistry and Biochemistry, California State University Northridge Northridge CA 91330-8262, USA
| | - Jheem D Medh
- Department of Chemistry and Biochemistry, California State University Northridge Northridge CA 91330-8262, USA
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Jaureguiberry MS, Tricerri MA, Sanchez SA, Finarelli GS, Montanaro MA, Prieto ED, Rimoldi OJ. Role of plasma membrane lipid composition on cellular homeostasis: learning from cell line models expressing fatty acid desaturases. Acta Biochim Biophys Sin (Shanghai) 2014; 46:273-82. [PMID: 24473084 DOI: 10.1093/abbs/gmt155] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [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] [Indexed: 11/14/2022] Open
Abstract
Experimental evidence has suggested that plasma membrane (PM)-associated signaling and hence cell metabolism and viability depend on lipid composition and organization. The aim of the present work is to develop a cell model to study the endogenous polyunsaturated fatty acids (PUFAs) effect on PM properties and analyze its influence on cholesterol (Chol) homeostasis. We have previously shown that by using a cell line over-expressing stearoyl-CoA-desaturase, membrane composition and organization coordinate cellular pathways involved in Chol efflux and cell viability by different mechanisms. Now, we expanded our studies to a cell model over-expressing both Δ5 and Δ6 desaturases, which resulted in a permanently higher PUFA content in PM. Furthermore, this cell line showed increased PM fluidity, Chol storage, and mitochondrial activity. In addition, human apolipoprotein A-I-mediated Chol removal was less efficient in these cells than in the corresponding control. Taken together, our results suggested that the cell functionality is preserved by regulating PM organization and Chol exportation and homeostasis.
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Affiliation(s)
- María S Jaureguiberry
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), La Plata 1900, Buenos Aires, Argentina
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Voloshyna I, Modayil S, Littlefield MJ, Belilos E, Belostocki K, Bonetti L, Rosenblum G, Carsons SE, Reiss AB. Plasma from rheumatoid arthritis patients promotes pro-atherogenic cholesterol transport gene expression in THP-1 human macrophages. Exp Biol Med (Maywood) 2013; 238:1192-7. [PMID: 24000379 DOI: 10.1177/1535370213503262] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Immunologic derangements in rheumatoid arthritis (RA) patients likely contribute to premature atherosclerotic cardiovascular disease (CVD). Traditional CVD risk factors do not reliably identify at-risk RA patients, probably because disease-associated mechanisms are not taken into account. The purpose of this study was to determine whether plasma from subjects with RA exhibits atheroma-promoting properties leading to disruption of cholesterol homeostasis in human monocytes/macrophages. Twenty-one healthy controls (HC) and 22 RA patients were enrolled in an IRB approved study at Winthrop University Hospital. Naïve THP-1 macrophages were exposed to plasma from each HC and RA patient. Following incubation, RNA and protein were isolated. QRT-PCR and Western blotting techniques were then used to measure expression of proteins responsible for cholesterol efflux (ATP binding cassette transporter (ABC)A1, ABCG1, 27-hydroxylase) and cholesterol uptake (CD36, ScR-A1, lectin oxidized low density lipoprotein receptor (LOX)-1, CXCL16). To confirm the pro-atherogenic effects of RA plasma on macrophages, foam cell formation was quantified. Results showed that RA plasma downregulates cholesterol efflux proteins and upregulates scavenger receptors CD36, LOX1 and CXCL16. These pro-atherogenic changes in gene expression in the presence of RA plasma are associated with augmented lipid accumulation and foam cell formation by THP-1 macrophages. RA plasma induces macrophage cholesterol overload. Demonstration of disrupted cholesterol homeostasis mediated by RA plasma provides further evidence of the involvement of the immune system in atherogenesis. Our data suggest that chronic exposure to RA plasma adversely affects the capacity of monocytes/macrophages in the arterial wall to metabolize cholesterol and maintain lipid homeostasis, thereby contributing to the development of premature atherosclerosis.
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Affiliation(s)
- Iryna Voloshyna
- Winthrop Research Institute and Division of Rheumatology, Allergy and Immunology, Department of Medicine, Winthrop-University Hospital, Mineola, NY 11501, USA
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Nguyen TM, Sawyer JK, Kelley KL, Davis MA, Rudel LL. Cholesterol esterification by ACAT2 is essential for efficient intestinal cholesterol absorption: evidence from thoracic lymph duct cannulation. J Lipid Res 2012; 53:95-104. [PMID: 22045928 PMCID: PMC3243485 DOI: 10.1194/jlr.m018820] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [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: 07/18/2011] [Revised: 10/11/2011] [Indexed: 01/21/2023] Open
Abstract
The hypothesis tested in this study was that cholesterol esterification by ACAT2 would increase cholesterol absorption efficiency by providing cholesteryl ester (CE) for incorporation into chylomicrons. The assumption was that absorption would be proportional to Acat2 gene dosage. Male ACAT2⁺/⁺, ACAT2⁺/⁻, and ACAT2⁻/⁻ mice were fed a diet containing 20% of energy as palm oil with 0.2% (w/w) cholesterol. Cholesterol absorption efficiency was measured by fecal dual-isotope and thoracic lymph duct cannulation (TLDC) methods using [³H]sitosterol and [¹⁴C]cholesterol tracers. Excellent agreement among individual mice was found for cholesterol absorption measured by both techniques. Cholesterol absorption efficiency in ACAT2⁻/⁻ mice was 16% compared with 46-47% in ACAT2⁺/⁺ and ACAT2⁺/⁻ mice. Chylomicrons from ACAT2⁺/⁺ and ACAT2⁺/⁻ mice carried ∼80% of total sterol mass as CE, whereas ACAT2⁻/⁻ chylomicrons carried >90% of sterol mass in the unesterified form. The total percentage of chylomicron mass as CE was reduced from 12% in the presence of ACAT2 to ∼1% in ACAT2⁻/⁻ mice. Altogether, the data demonstrate that ACAT2 increases cholesterol absorption efficiency by providing CE for chylomicron transport, but one copy of the Acat2 gene, providing ∼50% of ACAT2 mRNA and enzyme activity, was as effective as two copies in promoting cholesterol absorption.
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Affiliation(s)
| | - Janet K. Sawyer
- Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC
| | - Kathryn L. Kelley
- Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC
| | - Matthew A. Davis
- Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC
| | - Lawrence L. Rudel
- Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC
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Corcoran MP, Lichtenstein AH, Meydani M, Dillard A, Schaefer EJ, Lamon-Fava S. The effect of 17β-estradiol on cholesterol content in human macrophages is influenced by the lipoprotein milieu. J Mol Endocrinol 2011; 47:109-117. [PMID: 21830321 PMCID: PMC3168528 DOI: 10.1530/jme-10-0158] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Estrogen and testosterone are thought to modulate coronary heart disease (CHD) risk. To examine how these hormones affect human macrophage cholesterol transport, a key factor in atherogenesis, we obtained monocytes from healthy male and postmenopausal female donors (age 50–70 years). Cells were allowed to differentiate in autologous serum. Human monocyte-derived macrophages (HMDMs) were exposed to estrogen, testosterone, or vehicle, during differentiation.Cells were cholesterol enriched with oxidized low-density lipoprotein (oxLDL) in the presence of treatment. Cell cholesterol mass, efflux, and the expression of proteins involved in HMDM cholesterol transport were examined.Estrogen significantly reduced cholesteryl ester (CE) content in both female and male HMDMs while having no measurable effect on cholesterol efflux. Testosterone did not affect cholesterol content or efflux. Both hormones significantly but modestly affected the gene expression of several proteins involved in HMDM transport, yet these effects did not translate into significant changes in protein expression. In THP-1 macrophages, the effect of estrogen on CE content was more potent in unloaded macrophages and was estrogen receptor dependent. A trend for a reduction in nonoxLDL uptake by estrogen was observed and was also found to be dependent upon estrogen receptor activation. Our data indicate that estrogen, but not testosterone, reduces CE accumulation in HMDMs obtained from a CHD age relevant population, independent of changes in the expression of proteins important to macrophage cholesterol transport. In THP-1 cells, this effect is reduced in the presence of oxLDL, indicating that a pro-atherogenic lipoprotein milieu is an important variable in sex hormone modulation of CHD.
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Affiliation(s)
- Michael P Corcoran
- Lipid Metabolism Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington Street, Boston, MA 02111
| | - Alice H. Lichtenstein
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington Street, Boston, MA 02111
| | - Mohsen Meydani
- Vascular Biology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington Street, Boston, MA 02111
| | - Alice Dillard
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington Street, Boston, MA 02111
| | - Ernst J Schaefer
- Lipid Metabolism Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington Street, Boston, MA 02111
| | - Stefania Lamon-Fava
- Lipid Metabolism Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington Street, Boston, MA 02111
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Midzak A, Rone M, Aghazadeh Y, Culty M, Papadopoulos V. Mitochondrial protein import and the genesis of steroidogenic mitochondria. Mol Cell Endocrinol 2011; 336:70-9. [PMID: 21147195 PMCID: PMC3057322 DOI: 10.1016/j.mce.2010.12.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Revised: 12/03/2010] [Accepted: 12/05/2010] [Indexed: 11/23/2022]
Abstract
The principal site of regulation of steroid hormone biosynthesis is the transfer of cholesterol from the outer to inner mitochondrial membrane. Hormonal stimulation of steroidogenic cells promotes this mitochondrial lipid import through a multi-protein complex, termed the transduceosome, spanning the two membranes. The transduceosome complex is assembled from multiple proteins, such as the steroidogenic acute regulatory (STAR) protein and translocator protein (TSPO), and requires their targeting to the mitochondria for transduceosome function. The vast majority of mitochondrial proteins, including those participating in cholesterol import, are encoded in the nucleus. Their subsequent mitochondrial incorporation is performed through a series of protein import machineries located in the outer and inner mitochondrial membranes. Here we review our current knowledge of the mitochondrial cholesterol import machinery of the transduceosome. This is complemented with descriptions of mitochondrial protein import machineries and mechanisms by which these machineries assemble the transduceosome in steroidogenic mitochondria.
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Affiliation(s)
- Andrew Midzak
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Medicine, McGill University, Montreal, Quebec, H3G 1A4, Canada
| | - Malena Rone
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Medicine, McGill University, Montreal, Quebec, H3G 1A4, Canada
| | - Yassaman Aghazadeh
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Medicine, McGill University, Montreal, Quebec, H3G 1A4, Canada
| | - Martine Culty
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Medicine, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, H3G 1A4, Canada
| | - Vassilios Papadopoulos
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Medicine, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Biochemistry, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Correspondence at The Research Institute of the McGill University Health Center, Montreal General Hospital, 1650 Cedar Avenue, C10-148, Montreal, Quebec H3G 1A4, Canada. Tel: 514-934-1934 ext. 44580; Fax: 514-934-8261;
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Li T, Matozel M, Boehme S, Kong B, Nilsson LM, Guo G, Ellis E, Chiang JYL. Overexpression of cholesterol 7α-hydroxylase promotes hepatic bile acid synthesis and secretion and maintains cholesterol homeostasis. Hepatology 2011; 53:996-1006. [PMID: 21319191 PMCID: PMC3079544 DOI: 10.1002/hep.24107] [Citation(s) in RCA: 170] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 12/02/2010] [Indexed: 12/15/2022]
Abstract
UNLABELLED We reported previously that mice overexpressing cytochrome P450 7a1 (Cyp7a1; Cyp7a1-tg mice) are protected against high fat diet-induced hypercholesterolemia, obesity, and insulin resistance. Here, we investigated the underlying mechanism of bile acid signaling in maintaining cholesterol homeostasis in Cyp7a1-tg mice. Cyp7a1-tg mice had two-fold higher Cyp7a1 activity and bile acid pool than did wild-type mice. Gallbladder bile acid composition changed from predominantly cholic acid (57%) in wild-type to chenodeoxycholic acid (54%) in Cyp7a1-tg mice. Cyp7a1-tg mice had higher biliary and fecal cholesterol and bile acid secretion rates than did wild-type mice. Surprisingly, hepatic de novo cholesterol synthesis was markedly induced in Cyp7a1-tg mice but intestine fractional cholesterol absorption in Cyp7a1-tg mice remained the same as wild-type mice despite the presence of increased intestine bile acids. Interestingly, hepatic but not intestinal expression of several cholesterol (adenosine triphosphate-binding cassette G5/G8 [ABCG5/G8], scavenger receptor class B, member 1) and bile acid (ABCB11) transporters were significantly induced in Cyp7a1-tg mice. Treatment of mouse or human hepatocytes with a farnesoid X receptor (FXR) agonist GW4064 or bile acids induced hepatic Abcg5/g8 expression. A functional FXR binding site was identified in the Abcg5 gene promoter. Study of tissue-specific Fxr knockout mice demonstrated that loss of the Fxr gene in the liver attenuated bile acid induction of hepatic Abcg5/g8 and gallbladder cholesterol content, suggesting a role of FXR in the regulation of cholesterol transport. CONCLUSION This study revealed a new mechanism by which increased Cyp7a1 activity expands the hydrophobic bile acid pool, stimulating hepatic cholesterol synthesis and biliary cholesterol secretion without increasing intestinal cholesterol absorption. This study demonstrated that Cyp7a1 plays a critical role in maintaining cholesterol homeostasis and underscores the importance of bile acid signaling in regulating overall cholesterol homeostasis.
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Affiliation(s)
- Tiangang Li
- Department of Integrative Medical Sciences, Northeastern Ohio Univ’s Colleges of Medicine & Pharmacy, Rootstown, OH 44272
| | - Michelle Matozel
- Department of Integrative Medical Sciences, Northeastern Ohio Univ’s Colleges of Medicine & Pharmacy, Rootstown, OH 44272
| | - Shannon Boehme
- Department of Integrative Medical Sciences, Northeastern Ohio Univ’s Colleges of Medicine & Pharmacy, Rootstown, OH 44272
| | - Bo Kong
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160
| | - Lisa-Mari Nilsson
- Unit for Transplantation Surgery, Department of Clinical Science, Intervention and Technology, Karolinska Institute, Stockholm, Sweden
| | - Grace Guo
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160
| | - Ewa Ellis
- Unit for Transplantation Surgery, Department of Clinical Science, Intervention and Technology, Karolinska Institute, Stockholm, Sweden
| | - John Y. L. Chiang
- Department of Integrative Medical Sciences, Northeastern Ohio Univ’s Colleges of Medicine & Pharmacy, Rootstown, OH 44272
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Huttunen HJ, Havas D, Peach C, Barren C, Duller S, Xia W, Frosch MP, Hutter-Paier B, Windisch M, Kovacs DM. The acyl-coenzyme A: cholesterol acyltransferase inhibitor CI-1011 reverses diffuse brain amyloid pathology in aged amyloid precursor protein transgenic mice. J Neuropathol Exp Neurol 2010; 69:777-88. [PMID: 20613640 PMCID: PMC2918281 DOI: 10.1097/nen.0b013e3181e77ed9] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [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] [Indexed: 11/26/2022] Open
Abstract
Cerebral accumulation of amyloid-beta (Abeta) is characteristic of Alzheimer disease and of amyloid precursor protein (APP) transgenic mice. Here, we assessed the efficacy of CI-1011, an inhibitor of acyl-coenzyme A:cholesterol acyltransferase, which is suitable for clinical use, in reducing amyloid pathology in both young (6.5 months old) and aged (16 months old) human APP transgenic mice. Treatment of young animals with CI-1011 decreased amyloid plaque load in the cortex and hippocampus and reduced the levels of insoluble Abeta40 and Abeta42 and C-terminal fragments of APP in brain extracts. In aged mice, CI-1011 specifically reduced diffuse amyloid plaques with a minor effect on thioflavin S-positive dense-core plaques. Reduced diffusible amyloid was accompanied by suppression of astrogliosis and enhanced microglial activation. Collectively, these data suggest that CI-1011 treatment reduces amyloid burden in human APP mice by limiting generation and increasing clearance of diffusible Abeta.
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Affiliation(s)
- Henri J. Huttunen
- Neurobiology of Disease Laboratory, Genetics and Aging Research Unit, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
- MassGeneral Institute for Neurodegenerative Disease (MIND) and Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
- Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Daniel Havas
- JSW-Research Forschungslabor GmbH, Institute of Experimental Pharmacology, Grambach/Graz, Austria
| | - Camilla Peach
- Neurobiology of Disease Laboratory, Genetics and Aging Research Unit, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
- MassGeneral Institute for Neurodegenerative Disease (MIND) and Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Cory Barren
- Neurobiology of Disease Laboratory, Genetics and Aging Research Unit, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
- MassGeneral Institute for Neurodegenerative Disease (MIND) and Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Stephan Duller
- JSW-Research Forschungslabor GmbH, Institute of Experimental Pharmacology, Grambach/Graz, Austria
| | - Weiming Xia
- Center for Neurologic Diseases, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Matthew P. Frosch
- MassGeneral Institute for Neurodegenerative Disease (MIND) and Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Birgit Hutter-Paier
- JSW-Research Forschungslabor GmbH, Institute of Experimental Pharmacology, Grambach/Graz, Austria
| | - Manfred Windisch
- JSW-Research Forschungslabor GmbH, Institute of Experimental Pharmacology, Grambach/Graz, Austria
| | - Dora M. Kovacs
- Neurobiology of Disease Laboratory, Genetics and Aging Research Unit, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
- MassGeneral Institute for Neurodegenerative Disease (MIND) and Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
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Jenkins KT, Merkens LS, Tubb MR, Myatt L, Davidson WS, Steiner RD, Woollett LA. Enhanced placental cholesterol efflux by fetal HDL in Smith-Lemli-Opitz syndrome. Mol Genet Metab 2008; 94:240-7. [PMID: 18346920 PMCID: PMC3037116 DOI: 10.1016/j.ymgme.2008.01.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Accepted: 01/30/2008] [Indexed: 11/23/2022]
Abstract
Previous studies from this laboratory have shown that maternal-derived cholesterol can be effluxed from trophoblasts to fetal HDL and plasma. We had the opportunity to study for the first time the ability of HDL and plasma from a fetus with the Smith-Lemli-Opitz syndrome (SLOS) to efflux cholesterol from trophoblasts. It was unclear whether cholesterol could be effluxed to fetuses with SLOS since lipoprotein levels are often very low. To answer this question, cord blood was collected from the placentas of an SLOS fetus and unaffected fetuses just after delivery. Plasma cholesterol concentrations were very low in the affected fetus; cholesterol, 7-dehydrocholesterol, and 8-dehydocholesterol concentrations were 14.1, 4.5, and 5.2 mg/dl, respectively. The HDL from the fetal SLOS effluxed approximately 50% more cholesterol from a trophoblast cell line, were smaller in size, and had a lower cholesterol to phospholipid ratio as compared to HDL from unaffected fetuses or adults. Plasma from the SLOS fetus effluxed cholesterol to a similar percentage as unaffected fetal plasma or adult plasma, possibly due to fewer HDL particles as demonstrated in previous SLOS patients. These novel data demonstrate that the cholesterol-deficient SLOS fetus is able to obtain cholesterol from trophoblasts at a time when cholesterol is playing a critical role in development, and has implications for design of treatments for cholesterol deficiency syndromes as well as understanding of prenatal cholesterol transport in humans.
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Affiliation(s)
- Katie T. Jenkins
- Departments of Pathology and Laboratory Medicine, Genome Research Institute, University of Cincinnati Medical School, 2180 E. Galbraith Road, Cincinnati, OH 45237-0507, USA
| | - Louise S. Merkens
- Department of Pediatrics, Oregon Health & Science University, Portland, OR, USA
| | - Matthew R. Tubb
- Departments of Pathology and Laboratory Medicine, Genome Research Institute, University of Cincinnati Medical School, 2180 E. Galbraith Road, Cincinnati, OH 45237-0507, USA
| | - Leslie Myatt
- Departments of Obstetrics and Gynecology, Genome Research Institute, University of Cincinnati Medical School, 2180 E. Galbraith Road, Cincinnati, OH 45237-0507, USA
| | - W. Sean Davidson
- Departments of Pathology and Laboratory Medicine, Genome Research Institute, University of Cincinnati Medical School, 2180 E. Galbraith Road, Cincinnati, OH 45237-0507, USA
| | - Robert D. Steiner
- Department of Pediatrics, Oregon Health & Science University, Portland, OR, USA
- Departments of Molecular and Medical Genetics, Child Development and Rehabilitation Center, Doernbecher Children’s Hospital and Oregon Clinical and Translational Research Institute, Oregon Health & Science University, Portland, OR, USA
| | - Laura A. Woollett
- Departments of Pathology and Laboratory Medicine, Genome Research Institute, University of Cincinnati Medical School, 2180 E. Galbraith Road, Cincinnati, OH 45237-0507, USA
- Corresponding author. Fax: +1 513 558 1312. (L.A. Woollett)
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Abstract
The absorption of cholesterol by the proximal small intestine represents a major pathway for the entry of cholesterol into the body pools. This cholesterol is derived primarily from the bile and the diet. In adult humans, typically several hundred milligrams of cholesterol reach the liver from the intestine daily, with the potential to impact the plasma low density lipoprotein-cholesterol (LDL-C) concentration. There are three main phases involved in cholesterol absorption. The first occurs intraluminally and culminates in micellar solubilization of unesterified cholesterol which facilitates its movement up to the brush border membrane (BBM) of the enterocyte. The second phase involves the transport of cholesterol across the BBM by Niemann-Pick C1 Like-1 (NPC1L1), while the third phase entails a series of steps within the enterocyte involving the esterification of cholesterol and its incorporation, along with other lipids and apolipoprotein B48 (apo B48), into nascent chylomicrons (CM). The discovery of the role of NPC1L1 in intestinal sterol transport occurred directly as a consequence of efforts to identify the molecular target of ezetimibe, a novel, potent, and specific inhibitor of sterol absorption that is now widely used in combination therapy with statins for the management of hypercholesterolemia in the general population. Some aspects of the role of NPC1L1 in cholesterol absorption nevertheless remain controversial and are the subject of ongoing research. For example, one report suggests that NPC1L1 is located not in the plasma membrane but intracellularly where it is thought to be involved in cytosolic trafficking of cholesterol, while another concludes that a protein other than NPC1L1 is responsible for the high affinity binding of cholesterol on intestinal BBM. However, other new studies which show that the in vivo responsiveness of different species to ezetimibe correlates with NPC1L1 binding affinity further support the widely held belief that NPC1L1 does facilitate sterol uptake by the enterocyte and is the target of ezetimibe. Added to this is the unequivocal finding that deletion of the gene for NPC1L1 in mice results in a near complete prevention of cholesterol absorption and an accelerated rate of fecal neutral sterol excretion. In summary, the development of ezetimibe and the identification of NPC1L1 as a key player in sterol absorption have taken research on the molecular control of this pathway to an exciting new level. From this it is hoped that we will now be able to determine more precisely what effect, if any, other classes of lipid lowering agents, particularly the statins, might exert on the amount of intestinal cholesterol reaching the liver.
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Affiliation(s)
- Stephen D Turley
- Division of Digestive and Liver Diseases, Department of Internal Medicine, University of Texas Southwestern Medical School, 5323 Harry Hines Blvd., Dallas, TX 75390, USA
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