1
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Glatz JFC, Heather LC, Luiken JJFP. CD36 as a gatekeeper of myocardial lipid metabolism and therapeutic target for metabolic disease. Physiol Rev 2024; 104:727-764. [PMID: 37882731 DOI: 10.1152/physrev.00011.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 10/02/2023] [Accepted: 10/22/2023] [Indexed: 10/27/2023] Open
Abstract
The multifunctional membrane glycoprotein CD36 is expressed in different types of cells and plays a key regulatory role in cellular lipid metabolism, especially in cardiac muscle. CD36 facilitates the cellular uptake of long-chain fatty acids, mediates lipid signaling, and regulates storage and oxidation of lipids in various tissues with active lipid metabolism. CD36 deficiency leads to marked impairments in peripheral lipid metabolism, which consequently impact on the cellular utilization of multiple different fuels because of the integrated nature of metabolism. The functional presence of CD36 at the plasma membrane is regulated by its reversible subcellular recycling from and to endosomes and is under the control of mechanical, hormonal, and nutritional factors. Aberrations in this dynamic role of CD36 are causally associated with various metabolic diseases, in particular insulin resistance, diabetic cardiomyopathy, and cardiac hypertrophy. Recent research in cardiac muscle has disclosed the endosomal proton pump vacuolar-type H+-ATPase (v-ATPase) as a key enzyme regulating subcellular CD36 recycling and being the site of interaction between various substrates to determine cellular substrate preference. In addition, evidence is accumulating that interventions targeting CD36 directly or modulating its subcellular recycling are effective for the treatment of metabolic diseases. In conclusion, subcellular CD36 localization is the major adaptive regulator of cellular uptake and metabolism of long-chain fatty acids and appears a suitable target for metabolic modulation therapy to mend failing hearts.
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Affiliation(s)
- Jan F C Glatz
- Department of Genetics & Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Lisa C Heather
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, United Kingdom
| | - Joost J F P Luiken
- Department of Genetics & Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
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2
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Abstract
CD36 (also known as platelet glycoprotein IV) is expressed by a variety of different cell entities, where it possesses functions as a signaling receptor, but additionally acts as a transporter for long-chain fatty acids. This dual function of CD36 has been investigated for its relevance in immune and nonimmune cells. Although CD36 was first identified on platelets, the understanding of the role of CD36 in platelet biology remained scarce for decades. In the past few years, several discoveries have shed a new light on the CD36 signaling activity in platelets. Notably, CD36 has been recognized as a sensor for oxidized low-density lipoproteins in the circulation that mitigates the threshold for platelet activation under conditions of dyslipidemia. Thus, platelet CD36 transduces atherogenic lipid stress into an increased risk for thrombosis, myocardial infarction, and stroke. The underlying pathways that are affected by CD36 are the inhibition of cyclic nucleotide signaling pathways and simultaneously the induction of activatory signaling events. Furthermore, thrombospondin-1 secreted by activated platelets binds to CD36 and furthers paracrine platelet activation. CD36 also serves as a binding hub for different coagulation factors and, thus, contributes to the plasmatic coagulation cascade. This review provides a comprehensive overview of the recent findings on platelet CD36 and presents CD36 as a relevant target for the prevention of thrombotic events for dyslipidemic individuals with an elevated risk for thrombosis.
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Affiliation(s)
- Gerd Bendas
- Department of Pharmacy, University of Bonn, Bonn, Germany
| | - Martin Schlesinger
- Department of Pharmacy, University of Bonn, Bonn, Germany
- Federal Institute for Drugs and Medical Devices (BfArM), Bonn, Germany
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3
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Wen SY, Zhi X, Liu HX, Wang X, Chen YY, Wang L. Is the suppression of CD36 a promising way for atherosclerosis therapy? Biochem Pharmacol 2024; 219:115965. [PMID: 38043719 DOI: 10.1016/j.bcp.2023.115965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 12/05/2023]
Abstract
Atherosclerosis is the main underlying pathology of many cardiovascular diseases and is marked by plaque formation in the artery wall. It has posed a serious threat to the health of people all over the world. CD36 acts as a significant regulator of lipid homeostasis, which is closely associated with the onset and progression of atherosclerosis and may be a new therapeutic target. The abnormal overexpression of CD36 facilitates lipid accumulation, foam cell formation, inflammation, endothelial apoptosis, and thrombosis. Numerous natural products and lipid-lowering agents are found to target the suppression of CD36 or inhibit the upregulation of CD36 to prevent and treat atherosclerosis. Here, the structure, expression regulation and function of CD36 in atherosclerosis and its related pharmacological therapies are reviewed. This review highlights the importance of drugs targeting CD36 suppression in the treatment and prevention of atherosclerosis, in order to develop new therapeutic strategies and potential anti-atherosclerotic drugs both preclinically and clinically.
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Affiliation(s)
- Shi-Yuan Wen
- College of Basic Medical Sciences, Shanxi Medical University, Taiyuan, China
| | - Xiaoyan Zhi
- College of Basic Medical Sciences, Shanxi Medical University, Taiyuan, China
| | - Hai-Xin Liu
- School of Traditional Chinese Materia Medica, Shanxi University of Chinese Medicine, Taiyuan, China
| | - Xiaohui Wang
- College of Basic Medical Sciences, Shanxi Medical University, Taiyuan, China
| | - Yan-Yan Chen
- School of Medicine, Jiangsu University, Zhenjiang, China.
| | - Li Wang
- College of Basic Medical Sciences, Shanxi Medical University, Taiyuan, China.
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4
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Feng WW, Zuppe HT, Kurokawa M. The Role of CD36 in Cancer Progression and Its Value as a Therapeutic Target. Cells 2023; 12:1605. [PMID: 37371076 PMCID: PMC10296821 DOI: 10.3390/cells12121605] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 06/06/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
Cluster of differentiation 36 (CD36) is a cell surface scavenger receptor that plays critical roles in many different types of cancer, notably breast, brain, and ovarian cancers. While it is arguably most well-known for its fatty acid uptake functions, it is also involved in regulating cellular adhesion, immune response, and apoptosis depending on the cellular and environmental contexts. Here, we discuss the multifaceted role of CD36 in cancer biology, such as its role in mediating metastasis, drug resistance, and immune evasion to showcase its potential as a therapeutic target. We will also review existing approaches to targeting CD36 in pre-clinical studies, as well as discuss the only CD36-targeting drug to advance to late-stage clinical trials, VT1021. Given the roles of CD36 in the etiology of metabolic disorders, such as atherosclerosis, diabetes, and non-alcoholic fatty liver disease, the clinical implications of CD36-targeted therapy are wide-reaching, even beyond cancer.
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Affiliation(s)
- William W. Feng
- Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
| | - Hannah T. Zuppe
- School of Biomedical Sciences, Kent State University, Kent, OH 44240, USA
| | - Manabu Kurokawa
- School of Biomedical Sciences, Kent State University, Kent, OH 44240, USA
- Department of Biological Sciences, Kent State University, Kent, OH 44240, USA
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5
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Yang R, Liu Q, Zhang M. The Past and Present Lives of the Intraocular Transmembrane Protein CD36. Cells 2022; 12:cells12010171. [PMID: 36611964 PMCID: PMC9818597 DOI: 10.3390/cells12010171] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/19/2022] [Accepted: 12/27/2022] [Indexed: 01/03/2023] Open
Abstract
Cluster of differentiation 36 (CD36) belongs to the B2 receptors of the scavenger receptor class B family, which is comprised of single-chain secondary transmembrane glycoproteins. It is present in a variety of cell types, including monocytes, macrophages, microvascular endothelial cells, adipocytes, hepatocytes, platelets, skeletal muscle cells, kidney cells, cardiomyocytes, taste bud cells, and a variety of other cell types. CD36 can be localized on the cell surface, mitochondria, endoplasmic reticulum, and endosomes, playing a role in lipid accumulation, oxidative stress injury, apoptosis, and inflammatory signaling. Recent studies have found that CD36 is expressed in a variety of ocular cells, including retinal pigment epithelium (RPE), retinal microvascular endothelial cells, retinal ganglion cells (RGC), Müller cells, and photoreceptor cells, playing an important role in eye diseases, such as age-related macular degeneration (AMD), diabetic retinopathy (DR), and glaucoma. Therefore, a comprehensive understanding of CD36 function and downstream signaling pathways is of great significance for the prevention and treatment of eye diseases. This article reviews the molecular characteristics, distribution, and function of scavenger receptor CD36 and its role in ophthalmology in order to deepen the understanding of CD36 in eye diseases and provide new ideas for treatment strategies.
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Affiliation(s)
- Rucui Yang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou 515041, China
- Department of Ophthalmology, Shantou University Medical College, Shantou University, Shantou 515041, China
| | - Qingping Liu
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou 515041, China
| | - Mingzhi Zhang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou 515041, China
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6
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Karunakaran U, Elumalai S, Moon JS, Won KC. CD36 Signal Transduction in Metabolic Diseases: Novel Insights and Therapeutic Targeting. Cells 2021; 10:cells10071833. [PMID: 34360006 PMCID: PMC8305429 DOI: 10.3390/cells10071833] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/14/2021] [Accepted: 07/17/2021] [Indexed: 12/24/2022] Open
Abstract
The cluster of differentiation 36 (CD36) is a scavenger receptor present on various types of cells and has multiple biological functions that may be important in inflammation and in the pathogenesis of metabolic diseases, including diabetes. Here, we consider recent insights into how the CD36 response becomes deregulated under metabolic conditions, as well as the therapeutic benefits of CD36 inhibition, which may provide clues for developing strategies aimed at the treatment or prevention of diabetes associated with metabolic diseases. To facilitate this process further, it is important to pinpoint regulatory mechanisms that are relevant under physiological and pathological conditions. In particular, understanding the mechanisms involved in dictating specific CD36 downstream cellular outcomes will aid in the discovery of potent compounds that target specific CD36 downstream signaling cascades.
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Affiliation(s)
- Udayakumar Karunakaran
- Innovative Center for Aging Research, Yeungnam University Medical Center, Daegu 42415, Korea; (U.K.); (S.E.)
| | - Suma Elumalai
- Innovative Center for Aging Research, Yeungnam University Medical Center, Daegu 42415, Korea; (U.K.); (S.E.)
| | - Jun-Sung Moon
- Innovative Center for Aging Research, Yeungnam University Medical Center, Daegu 42415, Korea; (U.K.); (S.E.)
- Yeungnam University College of Medicine, Daegu 42415, Korea
- Correspondence: (J.-S.M.); (K.-C.W.); Tel.: +82-53-620-3825 (J.-S.M.); +82-53-620-3846 (K.-C.W.)
| | - Kyu-Chang Won
- Innovative Center for Aging Research, Yeungnam University Medical Center, Daegu 42415, Korea; (U.K.); (S.E.)
- Yeungnam University College of Medicine, Daegu 42415, Korea
- Correspondence: (J.-S.M.); (K.-C.W.); Tel.: +82-53-620-3825 (J.-S.M.); +82-53-620-3846 (K.-C.W.)
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7
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Zhang X, Fan J, Li H, Chen C, Wang Y. CD36 Signaling in Diabetic Cardiomyopathy. Aging Dis 2021; 12:826-840. [PMID: 34094645 PMCID: PMC8139204 DOI: 10.14336/ad.2020.1217] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 12/17/2020] [Indexed: 12/14/2022] Open
Abstract
Cluster of differentiation 36 (CD36), also referred to as scavenger receptor B2, has been shown to serve multiple functions in lipid metabolism, inflammatory signaling, oxidative stress, and energy reprogramming. As a scavenger receptor, CD36 interacts with various ligands, such as oxidized low-density lipoprotein (oxLDL), thrombospondin 1 (TSP-1), and fatty acid (FA), thereby activating specific downstream signaling pathways. Cardiac CD36 is mostly expressed on the surface of cardiomyocytes and endothelial cells. The pathophysiological process of diabetic cardiomyopathy (DCM) encompasses diverse metabolic abnormalities, such as enhanced transfer of cardiac myocyte sarcolemmal FA, increased levels of advanced glycation end-products, elevation in oxidative stress, impaired insulin signaling cascade, disturbance in calcium handling, and microvascular rarefaction which are closely related to CD36 signaling. This review presents a summary of the CD36 signaling pathway that acts mainly as a long-chain FA transporter in cardiac myocytes and functions as a receptor to bind to numerous ligands in endothelial cells. Finally, we summarize the recent basic research and clinical findings regarding CD36 signaling in DCM, suggesting a promising strategy to treat this condition.
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Affiliation(s)
- Xudong Zhang
- Division of Cardiology, Tongji Hospital, Tongji Medical College and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Jiahui Fan
- Division of Cardiology, Tongji Hospital, Tongji Medical College and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Huaping Li
- Division of Cardiology, Tongji Hospital, Tongji Medical College and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Chen Chen
- Division of Cardiology, Tongji Hospital, Tongji Medical College and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan, China
| | - Yan Wang
- Division of Cardiology, Tongji Hospital, Tongji Medical College and Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan, China
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8
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Shu H, Peng Y, Hang W, Nie J, Zhou N, Wang DW. The role of CD36 in cardiovascular disease. Cardiovasc Res 2020; 118:115-129. [PMID: 33210138 PMCID: PMC8752351 DOI: 10.1093/cvr/cvaa319] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 10/29/2020] [Indexed: 12/13/2022] Open
Abstract
CD36, also known as the scavenger receptor B2, is a multifunctional receptor widely expressed in various organs. CD36 plays a crucial role in the uptake of long-chain fatty acids, the main metabolic substrate in myocardial tissue. The maturation and transportation of CD36 is regulated by post-translational modifications, including phosphorylation, ubiquitination, glycosylation, and palmitoylation. CD36 is decreased in pathological cardiac hypertrophy caused by ischaemia-reperfusion and pressure overload, and increased in diabetic cardiomyopathy and atherosclerosis. Deficiency of CD36 alleviates diabetic cardiomyopathy and atherosclerosis, while overexpression of CD36 eliminates ischaemia-reperfusion damage, together suggesting that CD36 is closely associated with the progression of cardiovascular diseases and may be a new therapeutic target. This review summarizes the regulation and post-translational modifications of CD36 and evaluates its role in cardiovascular diseases and its potential as a therapeutic target.
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Affiliation(s)
- Hongyang Shu
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China.,Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan 430000, China
| | - Yizhong Peng
- Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China
| | - Weijian Hang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China.,Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan 430000, China
| | - Jiali Nie
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China.,Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan 430000, China
| | - Ning Zhou
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China.,Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan 430000, China
| | - Dao Wen Wang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China.,Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Huazhong University of Science and Technology, Wuhan 430000, China
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9
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Moon JS, Karunakaran U, Suma E, Chung SM, Won KC. The Role of CD36 in Type 2 Diabetes Mellitus: β-Cell Dysfunction and Beyond. Diabetes Metab J 2020; 44:222-233. [PMID: 32347024 PMCID: PMC7188969 DOI: 10.4093/dmj.2020.0053] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 03/25/2020] [Indexed: 12/24/2022] Open
Abstract
Impaired β-cell function is the key pathophysiology of type 2 diabetes mellitus, and chronic exposure of nutrient excess could lead to this tragedy. For preserving β-cell function, it is essential to understand the cause and mechanisms about the progression of β-cells failure. Glucotoxicity, lipotoxicity, and glucolipotoxicity have been suggested to be a major cause of β-cell dysfunction for decades, but not yet fully understood. Fatty acid translocase cluster determinant 36 (CD36), which is part of the free fatty acid (FFA) transporter system, has been identified in several tissues such as muscle, liver, and insulin-producing cells. Several studies have reported that induction of CD36 increases uptake of FFA in several cells, suggesting the functional interplay between glucose and FFA in terms of insulin secretion and oxidative metabolism. However, we do not currently know the regulating mechanism and physiological role of CD36 on glucolipotoxicity in pancreatic β-cells. Also, the downstream and upstream targets of CD36 related signaling have not been defined. In the present review, we will focus on the expression and function of CD36 related signaling in the pancreatic β-cells in response to hyperglycemia and hyperlipidemia (ceramide) along with the clinical studies on the association between CD36 and metabolic disorders.
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Affiliation(s)
- Jun Sung Moon
- Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea
| | | | - Elumalai Suma
- Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea
| | - Seung Min Chung
- Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea
| | - Kyu Chang Won
- Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea.
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10
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Soslau G. Extracellular adenine compounds within the cardiovascular system: Their source, metabolism and function. MEDICINE IN DRUG DISCOVERY 2019. [DOI: 10.1016/j.medidd.2020.100018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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11
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Pfleger J, Gross P, Johnson J, Carter RL, Gao E, Tilley DG, Houser SR, Koch WJ. G protein-coupled receptor kinase 2 contributes to impaired fatty acid metabolism in the failing heart. J Mol Cell Cardiol 2018; 123:108-117. [PMID: 30171848 DOI: 10.1016/j.yjmcc.2018.08.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 08/17/2018] [Accepted: 08/28/2018] [Indexed: 12/19/2022]
Abstract
Increased G protein-coupled receptor kinase (GRK)2 is central to heart failure (HF) pathogenesis, via desensitization of β-adrenergic receptors and loss of contractile reserve. Since GRK2 has been shown to compromise fatty acid (FA) oxidation, this kinase may link metabolic and contractile defects in HF. The aim of this study was to investigate the mechanistic role of GRK2 in FA metabolism and bioenergetics in the heart. For that purpose, we measured FA uptake and cluster of differentiation (CD)36 expression, phosphorylation, and ubiquitination in mice with cardiac-specific overexpression of GRK2 (TgGRK2) or expression of its c-terminus (GRK2 inhibitor- TgβARKct) or in global heterozygous GRK2 knockout (GRK2+/-) mice. Cellular bioenergetics were also measured in isolated cardiomyocytes following adenoviral delivery of exogenous GRK2, βARKct, or short hairpin GRK2 (shGRK2). Additionally, CD36 expression and phosphorylation were evaluated following transverse aortic constriction (TAC) in wild type (WT) and GRK2+/- mice. Our results show a 33% ± 0.81 reduction in FA uptake rate, accompanied by 51% ± 0.17 lower CD36 protein, and 70% ± 0.23 and 69% ± 0.18 increases in CD36 phosphorylation and ubiquitination, respectively, in the TgGRK2 mice. Moreover, an in vitro kinase assay suggests that GRK2 directly phosphorylates CD36. In isolated cardiomyocytes, GRK2 overexpression induced a 26% ± 2.21 decrease in maximal respiration, which was enhanced (20% ± 4.02-5.14) with inhibition of the kinase. Importantly, in hearts with systolic dysfunction, notable reductions in CD36 mRNA and protein, as well as a significant increase in CD36 phosphorylation were normalized in the GRK2+/- mice post-TAC. Thus, we propose that GRK2 up-regulation in HF is, at least partly, responsible for reduced FA uptake and oxidation and may be a nodal link between metabolic and contractile defects.
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Affiliation(s)
- Jessica Pfleger
- Center for Translational Medicine, Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Polina Gross
- Cardiovascular Research Center, Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Jaslyn Johnson
- Cardiovascular Research Center, Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Rhonda L Carter
- Center for Translational Medicine, Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Erhe Gao
- Center for Translational Medicine, Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Douglas G Tilley
- Center for Translational Medicine, Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Steven R Houser
- Cardiovascular Research Center, Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Walter J Koch
- Center for Translational Medicine, Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA.
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12
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CD36 in chronic kidney disease: novel insights and therapeutic opportunities. Nat Rev Nephrol 2017; 13:769-781. [DOI: 10.1038/nrneph.2017.126] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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13
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Zingg JM, Azzi A, Meydani M. α-Tocopheryl Phosphate Induces VEGF Expression via CD36/PI3Kγ in THP-1 Monocytes. J Cell Biochem 2017; 118:1855-1867. [PMID: 28059487 DOI: 10.1002/jcb.25871] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 01/05/2017] [Indexed: 12/20/2022]
Abstract
The CD36 scavenger receptor binds several ligands and mediates ligand uptake and ligand-dependent signal transduction and gene expression, events that may involve CD36 internalization. Here we show that CD36 internalization in THP-1 monocytes is triggered by α-tocopherol (αT) and more strongly by α-tocopheryl phosphate (αTP) and EPC-K1, a phosphate diester of αTP and L-ascorbic acid. αTP-triggered CD36 internalization is prevented by the specific covalent inhibitor of selective lipid transport by CD36, sulfo-N-succinimidyl oleate (SSO). Moreover, SSO inhibited the CD36-mediated uptake of 14C-labelled αTP suggesting that αTP binding and internalization of CD36 is involved in cellular αTP uptake, whereas the uptake of αT was less affected. Similar to that, inhibition of selective lipid transport of the SR-BI scavenger receptor resulted mainly in reduction of αTP and not αT uptake. In contrast, uptake of αT was mainly inhibited by Dynasore, an inhibitor of clathrin-mediated endocytosis, suggesting that the differential regulatory effects of αTP and αT on signaling may be influenced by their different routes of uptake. Interestingly, αTP and EPC-K1 also reduced the neutral lipid content of THP-1 cells and the phagocytosis of fluorescent Staphylococcus aureus bioparticles. Moreover, induction of the vascular endothelial growth factor (VEGF) promoter activity by αTP occurred via CD36/PI3Kγ/Akt, as it could be inhibited by specific inhibitors of this pathway (SSO, Wortmannin, AS-605240). These results suggest that αTP activates PI3Kγ/Akt signaling leading to VEGF expression in monocytes after binding to and/or transport by CD36, a receptor known to modulate angiogenesis in response to amyloid beta, oxLDL, and thrombospondin. J. Cell. Biochem. 118: 1855-1867, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Jean-Marc Zingg
- Vascular Biology Laboratory, JM USDA-Human Nutr. Res. Ctr. on Aging, Tufts University, Boston, Massachusetts 02111
| | - Angelo Azzi
- Vascular Biology Laboratory, JM USDA-Human Nutr. Res. Ctr. on Aging, Tufts University, Boston, Massachusetts 02111
| | - Mohsen Meydani
- Vascular Biology Laboratory, JM USDA-Human Nutr. Res. Ctr. on Aging, Tufts University, Boston, Massachusetts 02111
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Cabrera-Pastor A, Llansola M, Felipo V. Extracellular Protein Kinase A Modulates Intracellular Calcium/Calmodulin-Dependent Protein Kinase II, Nitric Oxide Synthase, and the Glutamate-Nitric Oxide-cGMP Pathway in Cerebellum. Differential Effects in Hyperammonemia. ACS Chem Neurosci 2016; 7:1753-1759. [PMID: 27673574 DOI: 10.1021/acschemneuro.6b00263] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Extracellular protein kinases, including cAMP-dependent protein kinase (PKA), modulate neuronal functions including N-methyl-d-aspartate (NMDA) receptor-dependent long-term potentiation. NMDA receptor activation increases calcium, which binds to calmodulin and activates nitric oxide synthase (NOS), increasing nitric oxide (NO), which activates guanylate cyclase, increasing cGMP, which is released to the extracellular fluid, allowing analysis of this glutamate-NO-cGMP pathway in vivo by microdialysis. The function of this pathway is impaired in hyperammonemic rats. The aims of this work were to assess (1) whether the glutamate-NO-cGMP pathway is modulated in cerebellum in vivo by an extracellular PKA, (2) the role of phosphorylation and activity of calcium/calmodulin-dependent protein kinase II (CaMKII) and NOS in the pathway modulation by extracellular PKA, and (3) whether the effects are different in hyperammonemic and control rats. The pathway was analyzed by in vivo microdialysis. The role of extracellular PKA was analyzed by inhibiting it with a membrane-impermeable inhibitor. The mechanisms involved were analyzed in freshly isolated cerebellar slices from control and hyperammonemic rats. In control rats, inhibiting extracellular PKA reduces the glutamate-NO-cGMP pathway function in vivo. This is due to reduction of CaMKII phosphorylation and activity, which reduces NOS phosphorylation at Ser1417 and NOS activity, resulting in reduced guanylate cyclase activation and cGMP formation. In hyperammonemic rats, under basal conditions, CaMKII phosphorylation and activity are increased, increasing NOS phosphorylation at Ser847, which reduces NOS activity, guanylate cyclase activation, and cGMP. Inhibiting extracellular PKA in hyperammonemic rats normalizes CaMKII phosphorylation and activity, NOS phosphorylation, NOS activity, and cGMP, restoring normal function of the pathway.
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Affiliation(s)
- Andrea Cabrera-Pastor
- Laboratorio
de Neurobiología, Centro Investigación Príncipe Felipe, Eduardo Primo-Yufera 3, 46012 Valencia, Spain
| | - Marta Llansola
- Laboratorio
de Neurobiología, Centro Investigación Príncipe Felipe, Eduardo Primo-Yufera 3, 46012 Valencia, Spain
| | - Vicente Felipo
- Laboratorio
de Neurobiología, Centro Investigación Príncipe Felipe, Eduardo Primo-Yufera 3, 46012 Valencia, Spain
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15
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Luiken JJFP, Chanda D, Nabben M, Neumann D, Glatz JFC. Post-translational modifications of CD36 (SR-B2): Implications for regulation of myocellular fatty acid uptake. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1862:2253-2258. [PMID: 27615427 DOI: 10.1016/j.bbadis.2016.09.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Revised: 08/14/2016] [Accepted: 09/02/2016] [Indexed: 01/19/2023]
Abstract
The membrane-associated protein CD36, now officially designated as SR-B2, is present in various tissues and fulfills multiple cellular functions. In heart and muscle, CD36 is the main (long-chain) fatty acid transporter, regulating myocellular fatty acid uptake via its vesicle-mediated reversible trafficking (recycling) between intracellular membrane compartments and the cell surface. CD36 is subject to various types of post-translational modification. This review focusses on the role of these modifications in further regulation of myocellular fatty acid uptake. Glycosylation, ubiquitination and palmitoylation are involved in regulating CD36 stability, while phosphorylation at extracellular sites affect the rate of fatty acid uptake. In addition, CD36 modification by O-linked N-acetylglucosamine may regulate the translocation of CD36 from endosomes to the cell surface. Acetylation of CD36 has also been reported, but possible effects on CD36 expression and/or functioning have not yet been addressed. Taken together, CD36 is subject to a multitude of post-translational modifications of which their functional implications are beginning to be understood. Moreover, further investigations are needed to disclose whether these post-translational modifications play a role in altered fatty acid uptake rates seen in several pathologies of heart and muscle. This article is part of a special issue entitled: The role of post-translational protein modifications on heart and vascular metabolism edited by Jason R.B. Dyck and Jan F.C. Glatz.
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Affiliation(s)
- Joost J F P Luiken
- Department of Genetics and Cell Biology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Dipanjan Chanda
- Department of Genetics and Cell Biology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Miranda Nabben
- Department of Genetics and Cell Biology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Dietbert Neumann
- Department of Genetics and Cell Biology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Jan F C Glatz
- Department of Genetics and Cell Biology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
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16
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van Oort MM, Drost R, Janβen L, Van Doorn JM, Kerver J, Van der Horst DJ, Luiken JJFP, Rodenburg KCW. Each of the four intracellular cysteines of CD36 is essential for insulin- or AMP-activated protein kinase-induced CD36 translocation. Arch Physiol Biochem 2014; 120:40-9. [PMID: 24377880 DOI: 10.3109/13813455.2013.876049] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Stimulation of cellular fatty acid uptake by induction of insulin signalling or AMP-kinase (AMPK) activation is due to translocation of the fatty acid-transporter CD36 from intracellular stores to the plasma membrane (PM). For investigating the role of the four Cys-residues within CD36's cytoplasmic tails in CD36 translocation, we constructed CHO-cells expressing CD36 mutants in which all four, two, or one of the intracellular Cys were replaced by Ser. Intracellular and PM localization of all mutants was similar to wild-type CD36 (CD36wt). Hence, the four Cys do not regulate sub-cellular CD36 localization. However, in contrast to CD36wt, insulin or AMPK activation failed to induce translocation of any of the mutants, indicating that all four intracellular Cys residues are essential for CD36 translocation. The mechanism of defective translocation of mutant CD36 is unknown, but appears not due to loss of S-palmitoylation of the cytoplasmic tails or to aberrant oligomerization of the mutants.
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Affiliation(s)
- Masja M van Oort
- Division of Endocrinology and Metabolism, Department of Biology and Institute of Biomembranes, Utrecht University , NL-3584 CH Utrecht , The Netherlands and
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17
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Yalak G, Vogel V. Extracellular phosphorylation and phosphorylated proteins: not just curiosities but physiologically important. Sci Signal 2012; 5:re7. [PMID: 23250399 DOI: 10.1126/scisignal.2003273] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mining of the literature and high-throughput mass spectrometry data from both healthy and diseased tissues and from body fluids reveals evidence that various extracellular proteins can exist in phosphorylated states. Extracellular kinases and phosphatases (ectokinases and ectophosphatases) are active in extracellular spaces during times of sufficiently high concentrations of adenosine triphosphate. There is evidence for a role of extracellular phosphorylation in various physiological functions, including blood coagulation, immune cell activation, and the formation of neuronal networks. Ectokinase activity is increased in some diseases, including cancer, Alzheimer's disease, and some microbial infections. We summarize the literature supporting the physiological and pathological roles of extracellularly localized protein kinases, protein phosphatases, and phosphorylated proteins and provide an analysis of the available mass spectrometry data to annotate potential extracellular phosphorylated proteins.
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Affiliation(s)
- Garif Yalak
- Department of Health Sciences and Technology, ETH Zurich, Wolfgang Pauli Strasse 10, HCI F443, CH-8093 Zurich, Switzerland
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18
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Chu LY, Silverstein RL. CD36 ectodomain phosphorylation blocks thrombospondin-1 binding: structure-function relationships and regulation by protein kinase C. Arterioscler Thromb Vasc Biol 2012; 32:760-7. [PMID: 22247259 DOI: 10.1161/atvbaha.111.242511] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE CD36 phosphorylation on its extracellular domain inhibits binding of thrombospondin-1. The mechanisms of cellular CD36 ectodomain phosphorylation and whether it can be regulated in cells are not known. We determined structure-function relationships of CD36 phosphorylation related to thrombospondin-1 peptide binding in vitro and explored mechanisms regulating phosphorylation by protein kinase C (PKC) in melanoma cells. METHODS AND RESULTS Phosphorylation of CD36 peptide on Thr92 by PKCα suppressed binding of thrombospondin-1 peptides in vitro, and the level of inhibition correlated with the level of phosphorylation. Basal phosphorylation levels of CD36 in vivo in platelets, endothelial cells, and melanoma cells were assessed by immunoprecipitation and immunoblot and were found to be very low. Treatment of CD36-transfected melanoma cells with phorbol 12-myristate 13-acetate (PMA), a PKC activator, induced substantial CD36 phosphorylation and decreased ligand-mediated recruitment of Src-family proteins to CD36. PMA treatment did not induce detectable extracellular or cell surface-associated kinase activity, and both cycloheximide and brefeldin A blocked CD36 phosphorylation. CONCLUSION New protein synthesis and trafficking through the Golgi are required for PMA-induced CD36 phosphorylation, suggesting that phosphorylation probably occurs intracellularly. These studies suggest a novel in vivo pathway for CD36 phosphorylation that modulates cellular affinity for thrombospondin-related proteins to blunt vascular cell signaling.
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Affiliation(s)
- Ling-Yun Chu
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
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19
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Lynes M, Narisawa S, Millán JL, Widmaier EP. Interactions between CD36 and global intestinal alkaline phosphatase in mouse small intestine and effects of high-fat diet. Am J Physiol Regul Integr Comp Physiol 2011; 301:R1738-47. [PMID: 21900644 DOI: 10.1152/ajpregu.00235.2011] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The mechanisms of the saturable component of long-chain fatty acid (LCFA) transport across the small intestinal epithelium and its regulation by a high-fat diet (HFD) are uncertain. It is hypothesized here that the putative fatty acid translocase/CD36 and intestinal alkaline phosphatases (IAPs) function together to optimize LCFA transport. Phosphorylated CD36 (pCD36) was expressed in mouse enterocytes and dephosphorylated by calf IAP (CIAP). Uptake of fluorescently tagged LCFA into isolated enteroctyes was increased when cells were treated with CIAP; this was blocked with a specific CD36 inhibitor. pCD36 colocalized in enterocytes with the global IAP (gIAP) isozyme and, specifically, coimmunoprecipitated with gIAP, but not the duodenal-specific isozyme (dIAP). Purified recombinant gIAP dephosphorylated immunoprecipitated pCD36, and antiserum to gIAP decreased initial LCFA uptake in enterocytes. Body weight, adiposity, and plasma leptin and triglycerides were significantly increased in HFD mice compared with controls fed a normal-fat diet. HFD significantly increased immunoreactive CD36 and gIAP, but not dIAP, in jejunum, but not duodenum. Uptake of LCFA was increased in a CD36-dependent manner in enterocytes from HFD mice. It is concluded that CD36 exists in its phosphorylated and dephosphorylated states in mouse enterocytes, that pCD36 is a substrate of gIAP, and that dephosphorylation by IAPs results in increased LCFA transport capability. HFD upregulates CD36 and gIAP in parallel and enhances CD36-dependent fatty acid uptake. The interactions between these proteins may be important for efficient fat transport in mouse intestine, but whether the changes in gIAP and CD36 in enterocytes contribute to HFD-induced obesity remains to be determined.
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Affiliation(s)
- Matthew Lynes
- Department of Biology, Boston University, Boston, Massachusetts 02215, USA
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20
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Involvement of CD36 and intestinal alkaline phosphatases in fatty acid transport in enterocytes, and the response to a high-fat diet. Life Sci 2011; 88:384-91. [DOI: 10.1016/j.lfs.2010.12.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 11/17/2010] [Accepted: 12/06/2010] [Indexed: 11/23/2022]
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21
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Glatz JFC, Luiken JJFP, Bonen A. Membrane Fatty Acid Transporters as Regulators of Lipid Metabolism: Implications for Metabolic Disease. Physiol Rev 2010; 90:367-417. [DOI: 10.1152/physrev.00003.2009] [Citation(s) in RCA: 515] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Long-chain fatty acids and lipids serve a wide variety of functions in mammalian homeostasis, particularly in the formation and dynamic properties of biological membranes and as fuels for energy production in tissues such as heart and skeletal muscle. On the other hand, long-chain fatty acid metabolites may exert toxic effects on cellular functions and cause cell injury. Therefore, fatty acid uptake into the cell and intracellular handling need to be carefully controlled. In the last few years, our knowledge of the regulation of cellular fatty acid uptake has dramatically increased. Notably, fatty acid uptake was found to occur by a mechanism that resembles that of cellular glucose uptake. Thus, following an acute stimulus, particularly insulin or muscle contraction, specific fatty acid transporters translocate from intracellular stores to the plasma membrane to facilitate fatty acid uptake, just as these same stimuli recruit glucose transporters to increase glucose uptake. This regulatory mechanism is important to clear lipids from the circulation postprandially and to rapidly facilitate substrate provision when the metabolic demands of heart and muscle are increased by contractile activity. Studies in both humans and animal models have implicated fatty acid transporters in the pathogenesis of diseases such as the progression of obesity to insulin resistance and type 2 diabetes. As a result, membrane fatty acid transporters are now being regarded as a promising therapeutic target to redirect lipid fluxes in the body in an organ-specific fashion.
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Affiliation(s)
- Jan F. C. Glatz
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands; and Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada
| | - Joost J. F. P. Luiken
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands; and Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada
| | - Arend Bonen
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands; and Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada
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22
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Michlewska S, McColl A, Rossi AG, Megson IL, Dransfield I. Clearance of dying cells and autoimmunity. Autoimmunity 2009; 40:267-73. [PMID: 17516208 DOI: 10.1080/08916930701357208] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Phagocytic clearance of apoptotic cells is an important physiologic homeostatic mechanism that is associated with non-inflammatory or anti-inflammatory sequalae. Disruption of the process of apoptotic cell clearance may contribute to development of a number of inflammatory and autoimmune diseases. In this review, we summarize the molecular pathways that have been suggested to account for phagocytic clearance of apoptotic cells. We discuss potential mechanisms for regulation of phagocytosis and the implications for development of autoimmunity.
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Affiliation(s)
- Sylwia Michlewska
- The Queen's Medical Research Institute, MRC Centre for Inflammation Research, University of Edinburgh Medical School, Edinburgh, Scotland, UK.
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23
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Febbraio M, Silverstein RL. CD36: implications in cardiovascular disease. Int J Biochem Cell Biol 2007; 39:2012-30. [PMID: 17466567 PMCID: PMC2034445 DOI: 10.1016/j.biocel.2007.03.012] [Citation(s) in RCA: 181] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 03/15/2007] [Accepted: 03/16/2007] [Indexed: 12/20/2022]
Abstract
CD36 is a broadly expressed membrane glycoprotein that acts as a facilitator of fatty acid uptake, a signaling molecule, and a receptor for a wide range of ligands, including apoptotic cells, modified forms of low density lipoprotein, thrombospondins, fibrillar beta-amyloid, components of Gram positive bacterial walls and malaria infected erythrocytes. CD36 expression on macrophages, dendritic and endothelial cells, and in tissues including muscle, heart, and fat, suggest diverse roles, and indeed, this is truly a multi-functional receptor involved in both homeostatic and pathological conditions. Despite an impressive increase in our knowledge of CD36 functions, in depth understanding of the mechanistic aspects of this protein remains elusive. This review focuses on CD36 in cardiovascular disease-what we know, and what we have yet to learn.
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Affiliation(s)
- Maria Febbraio
- Cleveland Clinic, Lerner Research Institute, Department of Cell Biology, NC-10, 9500 Euclid Avenue, Cleveland, OH 44195, United States.
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24
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Lautrette C, Loum-Ribot E, Petit D, Vermot-Desroches C, Wijdenes J, Jauberteau MO. Increase of Fas-induced apoptosis by inhibition of extracellular phosphorylation of Fas receptor in Jurkat cell line. Apoptosis 2006; 11:1195-204. [PMID: 16699962 DOI: 10.1007/s10495-006-6795-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Apoptosis signalling through the Fas pathway requires several steps of aggregation of the Fas receptor in the membrane, including aggregation that may occur in the absence of Fas ligand. Association of Fas domains is determinant to signal transmission following Fas ligand binding to a specific domain. The domains involved in Fas aggregation are located in its extracellular region and contain three potential protein kinase C-binding motifs. We therefore studied the possibility that phosphorylation of the extracellular region of Fas might be implicated in the regulation of Fas-mediated apoptosis. Inhibition experiments of extracellular phosphorylation were performed in human Jurkat T leukemia cells with K252b, an impermeant protein-kinase inhibitor. Extracellular phosphorylation of Fas receptor was related to ecto-kinase, as assessed by the [gamma-(32)P] ATP labelling of Fas-116 kDa aggregates, suppressed by K252b inhibitor which significantly increased the sensitivity to Fas-mediated apoptosis. Ecto-PKC involvement was demonstrated by bisindolylmaleimide VIII, a selective inhibitor of protein kinase C which significantly increased both Fas aggregation in the membrane and Fas-mediated apoptosis and by the addition of the PKC pseudo-substrate 19-36 which inhibited the phosphorylation of 116 kDa Fas aggregates. These data support a role for Fas phosphorylation in the decreased sensitivity to apoptosis in the Jurkat T leukemia cell line.
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Affiliation(s)
- C Lautrette
- Laboratory of Immunology and EA 3842, University Hospital, 2 avenue Martin Luther King, 87042 Limoges, France
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25
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Ho M, Hoang HL, Lee KM, Liu N, MacRae T, Montes L, Flatt CL, Yipp BG, Berger BJ, Looareesuwan S, Robbins SM. Ectophosphorylation of CD36 regulates cytoadherence of Plasmodium falciparum to microvascular endothelium under flow conditions. Infect Immun 2006; 73:8179-87. [PMID: 16299313 PMCID: PMC1307088 DOI: 10.1128/iai.73.12.8179-8187.2005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The adhesion of Plasmodium falciparum-infected erythrocytes (IRBCs) to human dermal microvascular endothelial cells (HDMECs) under flow conditions is regulated by a Src family kinase- and alkaline phosphatase (AP)-dependent mechanism. In this study, we showed that the target of the phosphatase activity is the ectodomain of CD36 at threonine-92 (Thr92). Mouse fibroblasts (NIH 3T3 cells) transfected with wild-type CD36 or a mutant protein in which Thr92 was substituted by Ala supported the rolling and adhesion of IRBCs. However, while the Src family kinase inhibitors PP1 and PP2 and the specific AP inhibitor levamisole significantly reduced IRBC adhesion to wild-type CD36 transfectants as with HDMECs, the inhibitors had no effect on IRBC adhesion to the mutant cells. Using a phosphospecific antibody directed at a 12-amino-acid peptide spanning Thr92, we demonstrated directly that CD36 was constitutively phosphorylated and could be dephosphorylated by exogenous AP. Endothelial CD36 was likewise constitutively phosphorylated. The phosphospecific antibody inhibited IRBC adhesion to HDMECs that could be reversed by preincubating the antibody with the phosphorylated but not the nonphosphorylated peptide. Pretreatment of HDMECs with AP abrogated the effect of PP1 on IRBC adhesion. Collectively, these results are consistent with a critical role for CD36 dephosphorylation through Src family kinase activation in regulating IRBC adhesion to vascular endothelium.
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Affiliation(s)
- May Ho
- Department of Microbiology and Infectious Diseases, University of Calgary, 3330 Hospital Dr. NW, Calgary, Alberta, T2N 4N1 Canada.
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26
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Koonen DPY, Glatz JFC, Bonen A, Luiken JJFP. Long-chain fatty acid uptake and FAT/CD36 translocation in heart and skeletal muscle. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1736:163-80. [PMID: 16198626 DOI: 10.1016/j.bbalip.2005.08.018] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2004] [Revised: 08/18/2005] [Accepted: 08/30/2005] [Indexed: 12/22/2022]
Abstract
Cellular long-chain fatty acid (LCFA) uptake constitutes a process that is not yet fully understood. LCFA uptake likely involves both passive diffusion and protein-mediated transport. Several lines of evidence support the involvement of a number of plasma membrane-associated proteins, including fatty acid translocase (FAT)/CD36, plasma membrane-bound fatty acid binding protein (FABPpm), and fatty acid transport protein (FATP). In heart and skeletal muscle primary attention has been given to unravel the mechanisms by which FAT/CD36 expression and function are regulated. It appears that both insulin and contractions induce the translocation of intracellular stored FAT/CD36 to the plasma membrane to increase cellular LCFA uptake. This review focuses on this novel mechanism of regulation of LCFA uptake in heart and skeletal muscle in health and disease. The distinct signaling pathways underlying insulin-induced and contraction-induced FAT/CD36 translocation will be discussed and a comparison will be made with the well-defined glucose transport system involving the glucose transporter GLUT4. Finally, it is hypothesized that malfunctioning of recycling of these transporters may lead to intracellular triacylglycerol (TAG) accumulation and cellular insulin resistance. Current data indicate a pivotal role for FAT/CD36 in the regulation of LCFA utilization in heart and skeletal muscle under normal conditions as well as during the altered LCFA utilization observed in obesity and insulin resistance. Hence, FAT/CD36 might provide a useful therapeutic target for the prevention or treatment of insulin resistance.
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Affiliation(s)
- Debby P Y Koonen
- Department of Molecular Genetics, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, NL-6200 MD Maastricht, The Netherlands
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27
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Deeg MA, Bowen RF. Phosphorylation decreases trypsin activation and apolipoprotein al binding to glycosylphosphatidylinositol-specific phospholipase D. Biochem Cell Biol 2002; 80:253-60. [PMID: 11989719 DOI: 10.1139/o02-004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD) is present in plasma as an apolipoprotein and as a cell-associated lipase. GPI-PLD mRNA levels are regulated, but it is unclear if posttranslational mechanisms also regulate GPI-PLD function. We examined the effect of protein kinase A phosphorylation on human serum GPI-PLD activity, trypsin activation, and apolipoprotein AI binding. Protein kinase A phosphorylation did not activate GPI-PLD activity in vitro, nor did phosphorylated GPI-PLD cleave a GPI-anchored protein from intact porcine erythrocytes. Trypsin cleaves the C-terminal beta propeller of purified human serum GPI-PLD to generate three immunodetectable fragments (75, 28, and 18 kDa) in association with a 12-fold increase in enzyme activity. After phosphorylation, the amounts of 28- and 18-kDa fragments were markedly decreased with trypsin treatment, and activity was only increased five-fold. Phosphorylation also inhibits binding of GPI-PLD to apolipoprotein AI. These data are the first demonstrating that phosphorylation may regulate GPI-PLD interaction with other proteins.
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Affiliation(s)
- Mark A Deeg
- Department of Medicine, Indiana University School of Medicine and the Department of Veterans Affairs, Indianapolis 46202, USA.
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28
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Luiken JJFP, Willems J, Coort SLM, Coumans WA, Bonen A, Van Der Vusse GJ, Glatz JFC. Effects of cAMP modulators on long-chain fatty-acid uptake and utilization by electrically stimulated rat cardiac myocytes. Biochem J 2002; 367:881-7. [PMID: 12093365 PMCID: PMC1222913 DOI: 10.1042/bj20020432] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2002] [Revised: 06/25/2002] [Accepted: 07/02/2002] [Indexed: 11/17/2022]
Abstract
Recently, we established that cellular contractions increase long-chain fatty-acid (FA) uptake by cardiac myocytes. This increase is dependent on the transport function of an 88 kDa membrane FA transporter, FA translocase (FAT/CD36), and, in analogy to skeletal muscle, is likely to involve its translocation from an intracellular pool to the sarcolemma. In the present study, we investigated whether cAMP-dependent signalling is involved in this translocation process. Isoproterenol, dibutyryl-cAMP and the phosphodiesterase (PDE) inhibitor, amrinone, which markedly raised the intracellular cAMP level, did not affect cellular FA uptake, but influenced the fate of intracellular FAs by directing these to mitochondrial oxidation in electrostimulated cardiac myocytes. The PDE inhibitors 3-isobutyl-1-methylxanthine, milrinone and dipyridamole each significantly stimulated FA uptake as well as intracellular cAMP levels, but these effects were quantitatively unrelated. The stimulatory effects of these PDE inhibitors were antagonized by sulpho- N -succinimidylpalmitate, indicating the involvement of FAT/CD36, albeit that the different PDE inhibitors use different molecular mechanisms to stimulate FAT/CD36-mediated FA uptake. Notably, 3-isobutyl-1-methylxanthine and milrinone increased the intrinsic activity of FAT/CD36, possibly through its covalent modification, and dipyridamole induces translocation of FAT/CD36 to the sarcolemma. Elevation of intracellular cGMP, but not of cAMP, by the PDE inhibitor zaprinast did not have any effect on FA uptake and metabolism by cardiac myocytes. The stimulatory effects of PDE inhibitors on cardiac FA uptake should be considered when applying these agents in clinical medicine.
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Affiliation(s)
- J J F P Luiken
- Department of Physiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, NL-6200 MD Maastricht, The Netherlands.
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29
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Vieira LL, Sacerdoti-Sierra N, Jaffe CL. Effect of pH and temperature on protein kinase release by Leishmania donovani. Int J Parasitol 2002; 32:1085-93. [PMID: 12117491 DOI: 10.1016/s0020-7519(02)00067-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
During their life cycle Leishmania are exposed to environments that differ markedly in pH and temperature. The effect of these factors on protein kinase release into the surrounding environment by Leishmania donovani promastigotes was examined. Promastigotes release protein kinase activity both constitutively and following induction by incubation with an exogenous substrate, phosvitin. The substrate specificity of the constitutive and induced activities was similar, unlike that previously described for Leishmania major promastigotes. The Leishmania donovani enzymes phosphorylate phosvitin, but not casein, mixed histones or protamine sulphate, and both activities are shed over a wide pH range from 6 to 9. Transfer of promastigotes from pH 7.4/30 degrees C to pH 5.0-5.5/37 degrees C, conditions that mimic those encountered by parasites following transmission from sandflies to a mammalian host and uptake by macrophages, inhibited release of the constitutive activity. Identical conditions had only a minor effect on induced protein kinase release. Both types of protein kinase activities released at pH 7.4 were still active when assayed at pH 5.0. Characterisation of the constitutive and induced promastigote protein kinases showed that casein kinase 1- and casein kinase 2-like activities are released by Leishmania donovani. Constitutive enzyme release decreased over time, however, the addition of phosvitin to these "casein kinase-depleted" promastigotes induced elevated casein kinase 1 and casein kinase 2 shedding. These results suggest that shed protein kinase might play a role in parasite survival and adaptation to host environments.
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Affiliation(s)
- Lita L Vieira
- Department of Parasitology, The Kuvin Centre for the Study of Infectious and Tropical Diseases, Hebrew University-Hadassah Medical School, P.O. Box 12272, 91120 Jerusalem, Israel
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Chin KV, Yang WL, Ravatn R, Kita T, Reitman E, Vettori D, Cvijic ME, Shin M, Iacono L. Reinventing the wheel of cyclic AMP: novel mechanisms of cAMP signaling. Ann N Y Acad Sci 2002; 968:49-64. [PMID: 12119267 DOI: 10.1111/j.1749-6632.2002.tb04326.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Mechanisms of cAMP signal transduction have been thoroughly investigated for more than 40 years. From the binding of hormonal ligands to their receptors on the outer surface of the plasma membrane to the cytoplasmic activation of effectors, the ensuing cAMP signaling cascades and the nuclear gene regulatory functions, coupled with the structural elucidation of the cAMP-dependent protein kinase (PKA) and in vivo functional characterizations of each of the components of PKA by homologous recombination gene targeting, our understanding of cAMP-mediated signal transduction has reached its pinnacle. Despite this trove of knowledge, some recent findings have emerged that suggest hitherto novel and alternative mechanisms of cAMP action that could increase the signaling bandwidth of cAMP and PKA in cell growth and transcriptional regulation. This article attempts to review some of these novel and unconventional mechanisms of cAMP and PKA signaling, and to generate further enthusiasm in investigating and validating these new frontiers of the cAMP signal transduction pathway.
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Affiliation(s)
- Khew-Voon Chin
- Department of Medicine and Pharmacology and The Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, New Jersey 08901, USA.
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Affiliation(s)
- J B Shabb
- Department of Biochemistry and Molecular Biology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9037, USA.
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Abstract
Thrombospondin-1 (TSP-1) is a matricellular protein that regulates cellular phenotype during tissue genesis and repair. It acts as a molecular facilitator by bringing together cytokines, growth factors, matrix components, membrane receptors and extracellular proteases. TSP-1 binds to a wide variety of integrin and non-integrin cell surface receptors. The binding sites for these receptors on TSP-1 are dispersed throughout the molecule, with most domains binding multiple receptors. In some cases, TSP-1 binds to multiple receptors concurrently, and recent data indicate that there is cross-talk between the receptor systems. Thus, TSP-1 may function to direct the clustering of receptors to specialized domains for adhesion and signal transduction.
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Affiliation(s)
- H Chen
- Division of Cancer Biology and Angiogenesis, Department of Pathology, Beth Israel Deaconess Medical Center, Research North, Rm. 270C, 99 Brookline Avenue, Boston, MA 02215, USA
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Communi D, Janssens R, Suarez-Huerta N, Robaye B, Boeynaems JM. Advances in signalling by extracellular nucleotides. the role and transduction mechanisms of P2Y receptors. Cell Signal 2000; 12:351-60. [PMID: 10889463 DOI: 10.1016/s0898-6568(00)00083-8] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Nucleotides are ubiquitous intercellular messengers whose actions are mediated by specific receptors. Since the first clonings in 1993, it is known that nucleotide receptors belong to two families: the ionotropic P2X receptors and the metabotropic P2Y receptors. Five human P2Y receptor subtypes have been cloned so far and a sixth one must still be isolated. In this review we will show that they differ by their preference for adenine versus uracil nucleotides and triphospho versus diphospho nucleotides, as well as by their transduction mechanisms and cell expression.
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Affiliation(s)
- D Communi
- Institute of Interdisciplinary Research, School of Medicine, Free University of Brussels, Brussels, Belgium
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Babinska A, Hogan MV, Sobocki T, Sobocka MB, Ehrlich YH, Kornecki E. Identification of ecto-PKC on surface of human platelets: role in maintenance of latent fibrinogen receptors. Am J Physiol Heart Circ Physiol 2000; 278:H2008-19. [PMID: 10843900 DOI: 10.1152/ajpheart.2000.278.6.h2008] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human platelets express a protein phosphorylation system on their surface. A specific protein kinase C (PKC) antibody, monoclonal antibody (MAb) 1.9, which binds to the catalytic domain of PKC and inhibits its activity, causes the aggregation of intact platelets while inhibiting the phosphorylation of platelet surface proteins. Photoaffinity labeling with 100 nM 8-azido-[alpha(32)P]ATP identified this ecto-PKC as a single surface protein of 43 kDa sensitive to proteolysis by extracellular 0.0005% trypsin. Inhibition of the binding of 8-azido-[alpha(32)P]ATP to the 43-kDa surface protein by MAb 1.9 identified this site as the active domain of ecto-PKC. Covalent binding of the azido-ATP molecule to the 43-kDa surface protein inhibited the phosphorylative activity of the platelet ecto-PKC. Furthermore, PKC pseudosubstrate inhibitory peptides directly induced the aggregation of platelets and inhibited azido-ATP binding to the 43-kDa protein. Platelet aggregation induced by MAb 1.9 and by PKC inhibitory peptides required the presence of fibrinogen and resulted in an increase in the level of intracellular free calcium concentration. This increase in intracellular free calcium concentration induced by MAb 1.9 was found to be dependent on the binding of fibrinogen to activated GPIIb/IIIa integrins, suggesting that MAb 1.9 causes Ca(2+) flux through the fibrinogen receptor complex. We conclude that a decrease in the state of phosphorylation of platelet surface proteins caused by inhibition of ecto-PKC results in membrane rearrangements that can induce the activation of latent fibrinogen receptors, leading to platelet aggregation. Accordingly, the maintenance of a physiological steady state of phosphorylation of proteins on the platelet surface by ecto-PKC activity appears to be one of the homeostatic mechanisms that maintain fibrinogen receptors of circulating platelets in a latent state that cannot bind fibrinogen.
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Affiliation(s)
- A Babinska
- Department of Anatomy and Cell Biology, State University of New York, Health Science Center at Brooklyn, 11203, New York
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Elalamy I, Said FA, Singer M, Couetil JP, Hatmi M. Inhibition by extracellular cAMP of phorbol 12-myristate 13-acetate-induced prostaglandin H synthase-2 expression in human pulmonary microvascular endothelial cells. Involvement of an ecto-protein kinase A activity. J Biol Chem 2000; 275:13662-7. [PMID: 10788484 DOI: 10.1074/jbc.275.18.13662] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Exposure of human pulmonary microvascular endothelial cells (HPMECs) to phorbol 12-myristate 13-acetate (PMA) leads to the increase of prostaglandin H synthase (PGHS)-2 protein levels. Under same conditions and according to its constitutive nature, no significant variation of PGHS-1 protein was noted. The elevation of the intracellular cAMP rate is known to enhance PGHS-2 levels through a protein kinase A pathway in various cells. To determine whether the extracellular cAMP also regulates the inducible expression of PGHS, cultured HPMECs were exposed to cAMP alone or in combination with PMA. The PMA-induced PGHS-2 protein was attenuated by the extracellular cAMP. In addition, PGHS-2 activity evaluated through 6-keto-PGF1alpha generation, which was enhanced by PMA was inhibited by extracellular cAMP. Furthermore, in HPMEC medium, PMA-induced PGHS-2 expression was accompanied by the generation of a transferable activity (TA) able to abolish platelet aggregation. This resulting TA was dependent from PGHS-2 pathway, because NS-398, a selective inhibitor of PGHS-2, suppressed its production. The inhibitory TA released by treated HPMECs was also prevented by extracellular cAMP. The specific protein kinase A (PKA) inhibitor blocked the extracellular cAMP effect on both PMA-induced 6-keto-PGF1alpha synthesis and inhibitory TA generation, suggesting the involvement of PKA signaling at the outer surface of HPMECs. Accordingly, we established, in phosphorylation experiments, the presence of an endothelial ecto-protein kinase activity, able to phosphorylate the synthetic substrate kemptide in a cAMP-dependent mode. Reverse transcription-polymerase chain reaction analysis showed that PMA-induced PGHS-2 mRNA was markedly reduced by extracellular cAMP. Together, these findings provide the first experimental evidence that extracellular cAMP is able to reduce HPMEC PGHS-2 expression in terms of mRNA, protein, and enzyme activity through an ecto-PKA pathway. In addition, they outline the potential role of endothelial PGHS-2 in the limitation of platelet activation during inflammatory processes.
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Affiliation(s)
- I Elalamy
- Unité de Pharmacologie Cellulaire, Unité Associée Institut Pasteur-INSERM U 485, 25 rue du Dr. Roux, 75724 Paris Cedex 15, France
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Godson C, Mitchell S, Harvey K, Petasis NA, Hogg N, Brady HR. Cutting edge: lipoxins rapidly stimulate nonphlogistic phagocytosis of apoptotic neutrophils by monocyte-derived macrophages. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:1663-7. [PMID: 10657608 DOI: 10.4049/jimmunol.164.4.1663] [Citation(s) in RCA: 462] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Lipoxins (LX) are lipoxygenase-derived eicosanoids generated during inflammation. LX inhibit polymorphonuclear neutrophil (PMN) chemotaxis and adhesion and are putative braking signals for PMN-mediated tissue injury. In this study, we report that LXA4 promotes another important step in the resolution phase of inflammation, namely, phagocytosis of apoptotic PMN by monocyte-derived macrophages (Mphi). LXA4 triggered rapid, concentration-dependent uptake of apoptotic PMN. This bioactivity was shared by stable synthetic LXA4 analogues (picomolar concentrations) but not by other eicosanoids tested. LXA4-triggered phagocytosis did not provoke IL-8 or monocyte chemoattractant protein-1 release. LXA4-induced phagocytosis was attenuated by anti-CD36, alphavbeta3, and CD18 mAbs. LXA4-triggered PMN uptake was inhibited by pertussis toxin and by 8-bromo-cAMP and was mimicked by Rp-cAMP, a protein kinase A inhibitor. LXA4 attenuated PGE2-stimulated protein kinase A activation in Mphi. These results suggest that LXA4 is an endogenous stimulus for PMN clearance during inflammation and provide a novel rationale for using stable synthetic analogues as anti-inflammatory compounds in vivo.
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Affiliation(s)
- C Godson
- Centre for Molecular Inflammation and Vascular Research, Mater Misericordiae Hospital, Department of Medicine, Dublin, Ireland.
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Redegeld FA, Caldwell CC, Sitkovsky MV. Ecto-protein kinases: ecto-domain phosphorylation as a novel target for pharmacological manipulation? Trends Pharmacol Sci 1999; 20:453-9. [PMID: 10542445 DOI: 10.1016/s0165-6147(99)01399-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
An increasing number of studies document the presence of protein kinases facing outwards at the cell surface of a diverse array of cells. These ecto-protein kinases phosphorylate cell-surface proteins and soluble extracellular substrates, and thus could affect many physiological processes involving cell-cell contacts, cellular differentiation and proliferation, ion fluxes and cellular activation. To date, only limited attention has been paid to exploring ecto-protein kinases as possible pharmacological targets. Here, the identification and physiological role of ecto-protein kinases in different biological systems is described; it is suggested that ecto-protein kinases are attractive and novel candidates for pharmacological manipulation under various (patho)physiological conditions.
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Affiliation(s)
- F A Redegeld
- Department of Pharmacology and Pathophysiology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, PO BOX 80082, 3508 TB Utrecht, Netherlands.
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Goding JW, Terkeltaub R, Maurice M, Deterre P, Sali A, Belli SI. Ecto-phosphodiesterase/pyrophosphatase of lymphocytes and non-lymphoid cells: structure and function of the PC-1 family. Immunol Rev 1998; 161:11-26. [PMID: 9553761 DOI: 10.1111/j.1600-065x.1998.tb01568.x] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many developmentally regulated membrane proteins of lymphocytes are ecto-enzymes, with their active sites on the external surface of the cell. These enzymes commonly have peptidase, phosphodiesterase or nucleotidase activity. Their biological roles are just beginning to be discovered. Although their expression is usually associated with particular stages of lymphoid differentiation, the same gene products are often expressed on the surface of certain non-lymphoid cell types outside the immune system, indicating that their functions cannot be unique to lymphocytes, nor can they be ubiquitous. The plasma cell membrane protein PC-1 (phosphodiesterase I; EC 3.1.4.1/nucleotide pyrophosphatase; EC 3.6.1.9), which was one of the first serological markers for lymphocyte subsets to be discovered, is a typical example. Within the immune system, PC-1 is confined to plasma cells, which represent about 0.1% of lymphocytes. However, PC-1 is also expressed on cells of the distal convoluted tubule of the kidney, chondrocytes, osteoblasts, epididymis and hepatocytes. Recent work has shown that PC-1 is a member of a multigene family of ecto-phosphodiesterases that currently has two other members, PD-1 alpha (autotaxin) and PD-1 beta (B10). Within this family, the extracellular domains are highly conserved, especially around the active site. In contrast, the transmembrane and cytoplasmic domains are highly divergent. Individual members of the eco-phosphodiesterase family have distinct patterns of distribution in different cell types, and even within the same cell. For example, PC-1 is present only on the basolateral surface of hepatocytes, while B10 (PD-1 beta) is confined to the apical surface. Analysis of conservation and differences in the sequence of their cytoplasmic tails may illuminate intracellular targetting signals. Ecto-phosphodiesterases may play a part in diverse activities in different tissues, including recycling of nucleotides. They may also regulate the concentration of pharmacologically active extracellular compounds such as adenosine or its derivatives and cell motility. Some members may modulate local concentrations of pyrophosphate, and hence influence calcification in bone and cartilage.
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Affiliation(s)
- J W Goding
- Department of Pathology and Immunology, Monash Medical School, Alfred Hospital, Prahran, Victoria, Australia.
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