101
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Conrad KS, Cheng TW, Ysselstein D, Heybrock S, Hoth LR, Chrunyk BA, Am Ende CW, Krainc D, Schwake M, Saftig P, Liu S, Qiu X, Ehlers MD. Lysosomal integral membrane protein-2 as a phospholipid receptor revealed by biophysical and cellular studies. Nat Commun 2017; 8:1908. [PMID: 29199275 PMCID: PMC5712522 DOI: 10.1038/s41467-017-02044-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 11/03/2017] [Indexed: 12/17/2022] Open
Abstract
Lysosomal integral membrane protein-2 (LIMP-2/SCARB2) contributes to endosomal and lysosomal function. LIMP-2 deficiency is associated with neurological abnormalities and kidney failure and, as an acid glucocerebrosidase receptor, impacts Gaucher and Parkinson's diseases. Here we report a crystal structure of a LIMP-2 luminal domain dimer with bound cholesterol and phosphatidylcholine. Binding of these lipids alters LIMP-2 from functioning as a glucocerebrosidase-binding monomer toward a dimeric state that preferentially binds anionic phosphatidylserine over neutral phosphatidylcholine. In cellular uptake experiments, LIMP-2 facilitates transport of phospholipids into murine fibroblasts, with a strong substrate preference for phosphatidylserine. Taken together, these biophysical and cellular studies define the structural basis and functional importance of a form of LIMP-2 for lipid trafficking. We propose a model whereby switching between monomeric and dimeric forms allows LIMP-2 to engage distinct binding partners, a mechanism that may be shared by SR-BI and CD36, scavenger receptor proteins highly homologous to LIMP-2.
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Affiliation(s)
- Karen S Conrad
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA
| | - Ting-Wen Cheng
- Neuroscience Research Unit, Pfizer Worldwide R&D, 610 Main Street, Cambridge, MA, 02139, USA
| | - Daniel Ysselstein
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Saskia Heybrock
- Biochemical Institute, Christian-Albrechts University Kiel, Olshausenstrasse 40, D-24098, Kiel, Germany
| | - Lise R Hoth
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA
| | - Boris A Chrunyk
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA
| | - Christopher W Am Ende
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA
| | - Dimitri Krainc
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Michael Schwake
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Paul Saftig
- Biochemical Institute, Christian-Albrechts University Kiel, Olshausenstrasse 40, D-24098, Kiel, Germany
| | - Shenping Liu
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA.
| | - Xiayang Qiu
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA.
| | - Michael D Ehlers
- Neuroscience Research Unit, Pfizer Worldwide R&D, 610 Main Street, Cambridge, MA, 02139, USA
- Biogen, 225 Binney St., Cambridge, MA, 02142, USA
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102
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Dhungana H, Huuskonen MT, Jaronen M, Lemarchant S, Ali H, Keksa-Goldsteine V, Goldsteins G, Kanninen KM, Koistinaho J, Malm T. Sulfosuccinimidyl oleate sodium is neuroprotective and alleviates stroke-induced neuroinflammation. J Neuroinflammation 2017; 14:237. [PMID: 29202856 PMCID: PMC5716243 DOI: 10.1186/s12974-017-1010-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 11/22/2017] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Ischemic stroke is one of the main causes of death and disability worldwide. It is caused by the cessation of cerebral blood flow resulting in the insufficient delivery of glucose and oxygen to the neural tissue. The inflammatory response initiated by ischemic stroke in order to restore tissue homeostasis in the acute phase of stroke contributes to delayed brain damage. METHODS By using in vitro models of neuroinflammation and in vivo model of permanent middle cerebral artery occlusion, we demonstrate the neuroprotective and anti-inflammatory effects of sulfosuccinimidyl oleate sodium (SSO). RESULTS SSO significantly reduced the lipopolysaccharide/interferon-γ-induced production of nitric oxide, interleukin-6 and tumor necrosis factor-α, and the protein levels of inflammatory enzymes including nitric oxide synthase 2, cyclooxygenase-2 (COX-2), and p38 mitogen-activated protein kinase (MAPK) in microglia, without causing cell toxicity. Although SSO failed to directly alleviate glutamate-induced excitotoxicity in murine cortical neurons, it prevented inflammation-induced neuronal death in microglia-neuron co-cultures. Importantly, oral administration of SSO in Balb/c mice subjected to permanent occlusion of the middle cerebral artery reduced microglial activation in the peri-ischemic area and attenuated brain damage. This in vivo neuroprotective effect of SSO was associated with a reduction in the COX-2 and heme oxygenase-1 immunoreactivities. CONCLUSIONS Our results suggest that SSO is an anti-inflammatory and a possible therapeutic candidate in diseases such as stroke where inflammation is a central hallmark.
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Affiliation(s)
- Hiramani Dhungana
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. box 1727, FI-70211, Kuopio, Finland
| | - Mikko T Huuskonen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. box 1727, FI-70211, Kuopio, Finland
| | - Merja Jaronen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. box 1727, FI-70211, Kuopio, Finland
| | - Sighild Lemarchant
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. box 1727, FI-70211, Kuopio, Finland
| | - Humair Ali
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. box 1727, FI-70211, Kuopio, Finland
| | - Velta Keksa-Goldsteine
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. box 1727, FI-70211, Kuopio, Finland
| | - Gundars Goldsteins
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. box 1727, FI-70211, Kuopio, Finland
| | - Katja M Kanninen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. box 1727, FI-70211, Kuopio, Finland
| | - Jari Koistinaho
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. box 1727, FI-70211, Kuopio, Finland.
| | - Tarja Malm
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. box 1727, FI-70211, Kuopio, Finland.
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103
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Widenmaier SB, Snyder NA, Nguyen TB, Arduini A, Lee GY, Arruda AP, Saksi J, Bartelt A, Hotamisligil GS. NRF1 Is an ER Membrane Sensor that Is Central to Cholesterol Homeostasis. Cell 2017; 171:1094-1109.e15. [DOI: 10.1016/j.cell.2017.10.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 08/14/2017] [Accepted: 09/30/2017] [Indexed: 12/13/2022]
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104
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Sodium fluorocitrate having protective effect on palmitate-induced beta cell death improves hyperglycemia in diabetic db/db mice. Sci Rep 2017; 7:12916. [PMID: 29018279 PMCID: PMC5635019 DOI: 10.1038/s41598-017-13365-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 09/21/2017] [Indexed: 02/06/2023] Open
Abstract
Beta cell loss and insulin resistance play roles in the pathogenesis of type 2 diabetes. Elevated levels of free fatty acids in plasma might contribute to the loss of beta cells. The objective of this study was to find a chemical that could protect against palmitate-induced beta cell death and investigate whether such chemical could improve hyperglycemia in mouse model of type 2 diabetes. Sodium fluorocitrate (SFC), an aconitase inhibitor, was found to be strongly and specifically protective against palmitate-induced INS-1 beta cell death. However, the protective effect of SFC on palmitate-induced cell death was not likely to be due to its inhibitory activity for aconitase since inhibition or knockdown of aconitase failed to protect against palmitate-induced cell death. Since SFC inhibited the uptake of palmitate into INS-1 cells, reduced metabolism of fatty acids was thought to be involved in SFC’s protective effect. Ten weeks of treatment with SFC in db/db diabetic mice reduced glucose level but remarkably increased insulin level in the plasma. SFC improved impairment of glucose-stimulated insulin release and also reduced the loss of beta cells in db/db mice. Conclusively, SFC possessed protective effect against palmitate-induced lipotoxicity and improved hyperglycemia in mouse model of type 2 diabetes.
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105
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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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106
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Paulus A, Maenen M, Drude N, Nascimento EBM, van Marken Lichtenbelt WD, Mottaghy FM, Bauwens M. Synthesis, radiosynthesis and in vitro evaluation of 18F-Bodipy-C16/triglyceride as a dual modal imaging agent for brown adipose tissue. PLoS One 2017; 12:e0182297. [PMID: 28817670 PMCID: PMC5560730 DOI: 10.1371/journal.pone.0182297] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 07/15/2017] [Indexed: 11/18/2022] Open
Abstract
Background Brown adipose tissue research is in the focus in the field of endocrinology. We designed a dual-modal fluorescent/PET fatty acid based tracer on commercially available Bodipy-C16, which can be synthesized to its corresponding triglyceride and which combines the benefits of fluorescent and PET imaging. Methods Bodipy-C16 was coupled to 1,3-diolein resulting in Bodipy-triglyceride. Bodipy-C16 and Bodipy-triglyceride compounds were radiolabeled with 18F using an 18F/19F exchange reaction to yield a dual-modal imaging molecule. Uptake of radiolabeled and non-labeled Bodipy-C16 and Bodipy-triglyceride was analyzed by fluorescence imaging and radioactive uptake in cultured adipocytes derived from human brown adipose tissue and white adipose tissue. Results Bodipy-C16 and Bodipy-triglyceride were successfully radiolabeled and Bodipy-C16 showed high shelf life and blood plasma stability (99% from 0–4 h). The uptake of Bodipy-C16 increased over time in cultured adipocytes, which was further enhanced after beta-adrenergic stimulation with norepinephrine. The uptake of Bodipy-C16 was inhibited by oleic acid and CD36 inhibitor sulfosuccinimidyl-oleate. The poor solubility of Bodipy-triglyceride did not allow stability or in vitro experiments. Conclusion The new developed dual modal fatty acid based tracers Bodipy-C16 and Bodipy-triglyceride showed promising results to stimulate further in vivo evaluation and will help to understand brown adipose tissues role in whole body energy expenditure.
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Affiliation(s)
- Andreas Paulus
- Department of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
- Department of Medical Imaging, Division of Nuclear Medicine, MUMC, Maastricht, The Netherlands
- Division of Nuclear Medicine, Uniklinikum Aachen, Aachen, Germany
- * E-mail:
| | - Marco Maenen
- Department of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Natascha Drude
- Division of Nuclear Medicine, Uniklinikum Aachen, Aachen, Germany
| | - Emmani B. M. Nascimento
- Department of Human Biology & Human Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht MD, The Netherlands
| | - Wouter D. van Marken Lichtenbelt
- Department of Human Biology & Human Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht MD, The Netherlands
| | - Felix M. Mottaghy
- Department of Medical Imaging, Division of Nuclear Medicine, MUMC, Maastricht, The Netherlands
- Division of Nuclear Medicine, Uniklinikum Aachen, Aachen, Germany
| | - Matthias Bauwens
- Department of Radiology and Nuclear Medicine, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
- Department of Medical Imaging, Division of Nuclear Medicine, MUMC, Maastricht, The Netherlands
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107
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Involvement of CD36 in Modulating the Decrease of NPY and AgRP Induced by Acute Palmitic Acid Stimulation in N1E-115 Cells. Nutrients 2017. [PMID: 28629148 PMCID: PMC5490605 DOI: 10.3390/nu9060626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Central nervous system (CNS) fatty acid sensing plays an important role in the regulation of food intake, and palmitic acid (PA) is the most important long chain fatty acid (LCFA) in the mammalian diet. To explore the effect of PA on central neuropeptide expression and the role of the cluster of the differentiation of 36 (CD36) in the process, N1E-115 cells were cultured with PA in the presence or absence of sulfosuccinimidyl-oleate (SSO), a CD36 inhibitor. Results showed that 10 μmol/L PA significantly reduced NPY and AgRP mRNA expression after 20 min of exposure, while the expression of CD36 was upregulated. The presence of SSO significantly attenuated the decrease of NPY and AgRP expression that was induced by PA alone, although no notable effect on PA- induced CD36 gene expression was observed. In conclusion, our study suggests the involvement of CD36 in the PA-induced decrease of NPY and AgRP in N1E-115 cells.
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108
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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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109
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Cao D, Luo J, Zang W, Chen D, Xu H, Shi H, Jing X. Gamma-Linolenic Acid Suppresses NF-κΒ Signaling via CD36 in the Lipopolysaccharide-Induced Inflammatory Response in Primary Goat Mammary Gland Epithelial Cells. Inflammation 2017; 39:1225-37. [PMID: 27121266 DOI: 10.1007/s10753-016-0358-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Gamma-linolenic acid (GLA) and linoleic acid (LA), which are both n-6 unsaturated fatty acids, play vital roles in lipopolysaccharide (LPS)-induced inflammation. The multi-functional protein scavenger receptor CD36 has also been shown to participate in inflammation. However, the molecular mechanisms underlying the interactions between CD36 and GLA or LA in LPS-induced inflammation remain unclear. We used small interfering RNA and adenoviral systems to manipulate CD36 expression in primary goat mammary gland epithelial cells (pGMECs), and the results showed that nuclear factor kappa B (NF-κB) levels were significantly decreased by CD36 receptor signaling following treatment with GLA but not LA. GLA inhibited NF-κB activation in LPS-induced pGMECs. However, silencing CD36 or deleting its fatty acid-binding domain blocked the anti-inflammatory effects of GLA, resulting in an increase in NF-κB activation and disrupting its localization during LPS-induced inflammation. The activity of the cytokines IL-1β, IL-6, and TNF-α, which act downstream of NF-κB, was also modulated when CD34 expression was manipulated by the addition of GLA in LPS-induced pGMECs. Our data suggest that GLA, but not LA, may interact with the CD36 fatty acid-binding domain to regulate the activation and localization of NF-κB in LPS-induced pGMECs.
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Affiliation(s)
- Duoyao Cao
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Jun Luo
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, Shaanxi, China.
| | - WenJuan Zang
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Dekun Chen
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Huifen Xu
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Huaiping Shi
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Xiaoqi Jing
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, Shaanxi, China
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110
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Niot I, Besnard P. Appetite control by the tongue-gut axis and evaluation of the role of CD36/SR-B2. Biochimie 2017; 136:27-32. [PMID: 28238842 DOI: 10.1016/j.biochi.2017.02.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 02/22/2017] [Indexed: 12/31/2022]
Abstract
Understanding the mechanisms governing food intake is a public health issue given the dramatic rise of obesity over the world. The overconsumption of tasty energy-dense foods rich in lipids is considered to be one of the nutritional causes of this epidemic. Over the last decade, the identification of fatty acid receptors in strategic places in the body (i.e. oro-intestinal tract and brain) has provided a major progress in the deciphering of regulatory networks involved in the control of dietary intake. Among these lipid sensors, CD36/SR-B2 appears to play a significant role since this membrane protein, known to bind long-chain fatty acid with a high affinity, was specifically found both in enterocytes and in a subset of taste bud cells and entero-endocrine cells. After a short overview on CD36/SR-B2 structure, function and regulation, this mini-review proposes to analyze the key findings about the role of CD36/SR-B2 along of the tongue-gut axis in relation to appetite control. In addition, we discuss whether obesogenic diets might impair lipid sensing mediated by CD36/SR-B2 along this axis.
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Affiliation(s)
- Isabelle Niot
- Physiologie de la Nutrition et Toxicologie (NUTox), LCN UMR 1231, INSERM/AgroSupDijon/Univ. Bourgogne Franche-Comté, F-21000, Dijon, France.
| | - Philippe Besnard
- Physiologie de la Nutrition et Toxicologie (NUTox), LCN UMR 1231, INSERM/AgroSupDijon/Univ. Bourgogne Franche-Comté, F-21000, Dijon, France.
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111
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Tim-3 inhibits macrophage control of Listeria monocytogenes by inhibiting Nrf2. Sci Rep 2017; 7:42095. [PMID: 28205579 PMCID: PMC5311873 DOI: 10.1038/srep42095] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 01/04/2017] [Indexed: 12/30/2022] Open
Abstract
T cell immunoglobulin mucin-3 (Tim-3) is an immune checkpoint inhibitor and its dysregulation has been related to T cell tolerance and many immune disorders, such as tumors and infection tolerance. However, the physiopathology roles of Tim-3 in innate immunity remain elusive. Here, we demonstrate that Tim-3 inhibits macrophage phagocytosis of L. monocytogenes by inhibiting the nuclear erythroid 2-related factor 2 (Nrf2) signaling pathway and increases bacterial burden. Tim-3 signaling promotes Nrf2 degradation by increasing its ubiquitination and, as a result, decreasing its nuclear translocation. CD36 and heme oxygenase-1 (HO-1), two downstream molecules in the Tim-3-Nrf2 signaling axis, are involved in the Tim-3- mediated immune evasion of L. monocytogenes both in vitro and in vivo. We here identified new mechanisms by which Tim-3 induces infection tolerance. By modulating the Tim-3 pathway, we demonstrate the feasibility of manipulating macrophage function as a potent tool for treating infectious diseases, such as Listeria infection.
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112
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Suresh K, Servinsky L, Reyes J, Undem C, Zaldumbide J, Rentsendorj O, Modekurty S, Dodd-O JM, Scott A, Pearse DB, Shimoda LA. CD36 mediates H2O2-induced calcium influx in lung microvascular endothelial cells. Am J Physiol Lung Cell Mol Physiol 2016; 312:L143-L153. [PMID: 27913425 DOI: 10.1152/ajplung.00361.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 11/11/2016] [Accepted: 11/30/2016] [Indexed: 11/22/2022] Open
Abstract
Elevated levels of reactive oxygen species and intracellular Ca2+ play a key role in endothelial barrier dysfunction in acute lung injury. We previously showed that H2O2-induced increases in intracellular calcium concentrations ([Ca2+]i) in lung microvascular endothelial cells (LMVECs) involve the membrane Ca2+ channel, transient receptor potential vanilloid-4 (TRPV4) and that inhibiting this channel attenuated H2O2-induced barrier disruption in vitro. We also showed that phosphorylation of TRPV4 by the Src family kinase, Fyn, contributes to H2O2-induced Ca2+ influx in LMVEC. In endothelial cells, Fyn is tethered to the cell membrane by CD36, a fatty acid transporter. In this study, we assessed the effect of genetic loss or pharmacological inhibition of CD36 on Ca2+ responses to H2O2 H2O2-induced Ca2+ influx was attenuated in LMVEC isolated from mice lacking CD36 (CD36-/-). TRPV4 expression and function was unchanged in LMVEC isolated from wild-type (WT) and CD36-/- mice, as well as mice with deficiency for Fyn (Fyn-/-). TRPV4 immunoprecipitated with Fyn, but this interaction was decreased in CD36-/- LMVEC. The amount of phosphorylated TRPV4 was decreased in LMVEC from CD36-/- mice compared with WT controls. Loss of CD36 altered subcellular localization of Fyn, while inhibition of CD36 fatty acid transport with succinimidyl oleate did not attenuate H2O2-induced Ca2+ influx. Lastly, we found that CD36-/- mice were protected from ischemia-reperfusion injury in vivo. In conclusion, our data suggest that CD36 plays an important role in H2O2-mediated lung injury and that the mechanism may involve CD36-dependent scaffolding of Fyn to the cell membrane to facilitate TRPV4 phosphorylation.
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Affiliation(s)
- Karthik Suresh
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland;
| | - Laura Servinsky
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jose Reyes
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Clark Undem
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Joel Zaldumbide
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Otgonchimeg Rentsendorj
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Sruti Modekurty
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jeffrey M Dodd-O
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Alan Scott
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - David B Pearse
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Larissa A Shimoda
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
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113
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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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114
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A new leptin-mediated mechanism for stimulating fatty acid oxidation: a pivotal role for sarcolemmal FAT/CD36. Biochem J 2016; 474:149-162. [PMID: 27827305 DOI: 10.1042/bcj20160804] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 10/03/2016] [Accepted: 11/08/2016] [Indexed: 12/15/2022]
Abstract
Leptin stimulates fatty acid oxidation in muscle and heart; but, the mechanism by which these tissues provide additional intracellular fatty acids for their oxidation remains unknown. We examined, in isolated muscle and cardiac myocytes, whether leptin, via AMP-activated protein kinase (AMPK) activation, stimulated fatty acid translocase (FAT/CD36)-mediated fatty acid uptake to enhance fatty acid oxidation. In both mouse skeletal muscle and rat cardiomyocytes, leptin increased fatty acid oxidation, an effect that was blocked when AMPK phosphorylation was inhibited by adenine 9-β-d-arabinofuranoside or Compound C. In wild-type mice, leptin induced the translocation of FAT/CD36 to the plasma membrane and increased fatty acid uptake into giant sarcolemmal vesicles and into cardiomyocytes. In muscles of FAT/CD36-KO mice, and in cardiomyocytes in which cell surface FAT/CD36 action was blocked by sulfo-N-succinimidyl oleate, the leptin-stimulated influx of fatty acids was inhibited; concomitantly, the normal leptin-stimulated increase in fatty acid oxidation was also prevented, despite the normal leptin-induced increase in AMPK phosphorylation. Conversely, in muscle of AMPK kinase-dead mice, leptin failed to induce the translocation of FAT/CD36, along with a failure to stimulate fatty acid uptake and oxidation. Similarly, when siRNA was used to reduce AMPK in HL-1 cardiomyocytes, leptin failed to induce the translocation of FAT/CD36. Our studies have revealed a novel mechanism of leptin-induced fatty acid oxidation in muscle tissue; namely, this process is dependent on the activation of AMPK to induce the translocation of FAT/CD36 to the plasma membrane, thereby stimulating fatty acid uptake. Without increasing this leptin-stimulated, FAT/CD36-dependent fatty acid uptake process, leptin-stimulated AMPK phosphorylation does not enhance fatty acid oxidation.
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115
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Salameh A, Daquinag AC, Staquicini DI, An Z, Hajjar KA, Pasqualini R, Arap W, Kolonin MG. Prohibitin/annexin 2 interaction regulates fatty acid transport in adipose tissue. JCI Insight 2016; 1. [PMID: 27468426 DOI: 10.1172/jci.insight.86351] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We have previously identified prohibitin (PHB) and annexin A2 (ANX2) as proteins interacting on the surface of vascular endothelial cells in white adipose tissue (WAT) of humans and mice. Here, we demonstrate that ANX2 and PHB also interact in adipocytes. Mice lacking ANX2 have normal WAT vascularization, adipogenesis, and glucose metabolism but display WAT hypotrophy due to reduced fatty acid uptake by WAT endothelium and adipocytes. By using cell culture systems in which ANX2/PHB binding is disrupted either genetically or through treatment with a blocking peptide, we show that fatty acid transport efficiency relies on this protein complex. We also provide evidence that the interaction between ANX2 and PHB mediates fatty acid transport from the endothelium into adipocytes. Moreover, we demonstrate that ANX2 and PHB form a complex with the fatty acid transporter CD36. Finally, we show that the colocalization of PHB and CD36 on adipocyte surface is induced by extracellular fatty acids. Together, our results suggest that an unrecognized biochemical interaction between ANX2 and PHB regulates CD36-mediated fatty acid transport in WAT, thus revealing a new potential pathway for intervention in metabolic diseases.
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Affiliation(s)
- Ahmad Salameh
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Alexes C Daquinag
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Daniela I Staquicini
- University of New Mexico Comprehensive Cancer Center and Division of Molecular Medicine, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA
| | - Zhiqiang An
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Katherine A Hajjar
- Departments of Pediatrics, Cell and Developmental Biology, and Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Renata Pasqualini
- University of New Mexico Comprehensive Cancer Center and Division of Molecular Medicine, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA
| | - Wadih Arap
- University of New Mexico Comprehensive Cancer Center and Division of Hematology/Oncology, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA
| | - Mikhail G Kolonin
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA
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116
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Xia W, Xu X, Fu Y, Ye X, Tsuno N, Santoso S. CD36 deficiency among South-East Asian populations. ACTA ACUST UNITED AC 2016. [DOI: 10.1111/voxs.12261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- W. Xia
- Institute of Blood Transfusion; Guangzhou Blood Centre; Guangzhou Guangdong China
| | - X. Xu
- Institute of Blood Transfusion; Guangzhou Blood Centre; Guangzhou Guangdong China
| | - Y. Fu
- Institute of Blood Transfusion; Guangzhou Blood Centre; Guangzhou Guangdong China
| | - X. Ye
- Institute of Blood Transfusion; Guangzhou Blood Centre; Guangzhou Guangdong China
| | - N. Tsuno
- Department of Transfusion Medicine; The University of Tokyo; Tokyo Japan
| | - S. Santoso
- Institute for Clinical Immunology and Transfusion Medicine; Justus-Liebig University Giessen; Giessen Germany
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117
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Yao CH, Fowle-Grider R, Mahieu NG, Liu GY, Chen YJ, Wang R, Singh M, Potter GS, Gross RW, Schaefer J, Johnson SL, Patti GJ. Exogenous Fatty Acids Are the Preferred Source of Membrane Lipids in Proliferating Fibroblasts. Cell Chem Biol 2016; 23:483-93. [PMID: 27049668 PMCID: PMC5510604 DOI: 10.1016/j.chembiol.2016.03.007] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 02/11/2016] [Accepted: 03/11/2016] [Indexed: 12/11/2022]
Abstract
Cellular proliferation requires the formation of new membranes. It is often assumed that the lipids needed for these membranes are synthesized mostly de novo. Here, we show that proliferating fibroblasts prefer to take up palmitate from the extracellular environment over synthesizing it de novo. Relative to quiescent fibroblasts, proliferating fibroblasts increase their uptake of palmitate, decrease fatty acid degradation, and instead direct more palmitate to membrane lipids. When exogenous palmitate is provided in the culture media at physiological concentrations, de novo synthesis accounts for only a minor fraction of intracellular palmitate in proliferating fibroblasts as well as proliferating HeLa and H460 cells. Blocking fatty acid uptake decreased the proliferation rate of fibroblasts, HeLa, and H460 cells, while supplementing media with exogenous palmitate resulted in decreased glucose uptake and rendered cells less sensitive to glycolytic inhibition. Our results suggest that cells scavenging exogenous lipids may be less susceptible to drugs targeting glycolysis and de novo lipid synthesis.
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Affiliation(s)
- Cong-Hui Yao
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA; Department of Medicine, Washington University, St. Louis, MO 63110, USA
| | - Ronald Fowle-Grider
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA; Department of Medicine, Washington University, St. Louis, MO 63110, USA
| | - Nathanial G Mahieu
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA; Department of Medicine, Washington University, St. Louis, MO 63110, USA
| | - Gao-Yuan Liu
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA; Division of Bioorganic and Molecular Pharmacology, Department of Internal Medicine, Washington University, St. Louis, MO 63110, USA
| | - Ying-Jr Chen
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA; Department of Medicine, Washington University, St. Louis, MO 63110, USA
| | - Rencheng Wang
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA; Department of Medicine, Washington University, St. Louis, MO 63110, USA; Department of Genetics, Washington University, St. Louis, MO 63110, USA
| | - Manmilan Singh
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA
| | - Gregory S Potter
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA
| | - Richard W Gross
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA; Division of Bioorganic and Molecular Pharmacology, Department of Internal Medicine, Washington University, St. Louis, MO 63110, USA
| | - Jacob Schaefer
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA
| | - Stephen L Johnson
- Department of Genetics, Washington University, St. Louis, MO 63110, USA
| | - Gary J Patti
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA; Department of Medicine, Washington University, St. Louis, MO 63110, USA.
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118
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Abumrad NA, Goldberg IJ. CD36 actions in the heart: Lipids, calcium, inflammation, repair and more? Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1442-9. [PMID: 27004753 DOI: 10.1016/j.bbalip.2016.03.015] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 03/14/2016] [Accepted: 03/15/2016] [Indexed: 01/15/2023]
Abstract
CD36 is a multifunctional immuno-metabolic receptor with many ligands. One of its physiological functions in the heart is the high-affinity uptake of long-chain fatty acids (FAs) from albumin and triglyceride rich lipoproteins. CD36 deletion markedly reduces myocardial FA uptake in rodents and humans. The protein is expressed on endothelial cells and cardiomyocytes and at both sites is likely to contribute to FA uptake by the myocardium. CD36 also transduces intracellular signaling events that influence how the FA is utilized and mediate metabolic effects of FA in the heart. CD36 transduced signaling regulates AMPK activation in a way that adjusts oxidation to FA uptake. It also impacts remodeling of myocardial phospholipids and eicosanoid production, effects exerted via influencing intracellular calcium (iCa(2+)) and the activation of phospholipases. Under excessive FA supply CD36 contributes to lipid accumulation, inflammation and dysfunction. However, it is also important for myocardial repair after injury via its contribution to immune cell clearance of apoptotic cells. This review describes recent progress regarding the multiple actions of CD36 in the heart and highlights those areas requiring future investigation. This article is part of a Special Issue entitled: Heart Lipid Metabolism edited by G.D. Lopaschuk.
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Affiliation(s)
- Nada A Abumrad
- Departments of Medicine and Cell Biology, Washington University, St. Louis, MO, United States..
| | - Ira J Goldberg
- Division of Endocrinology, Diabetes and Metabolism, New York University School of Medicine, New York, NY, United States
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119
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CD36 is a co-receptor for hepatitis C virus E1 protein attachment. Sci Rep 2016; 6:21808. [PMID: 26898231 PMCID: PMC4761891 DOI: 10.1038/srep21808] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 01/08/2016] [Indexed: 02/06/2023] Open
Abstract
The cluster of differentiation 36 (CD36) is a membrane protein related to lipid metabolism. We show that HCV infection in vitro increased CD36 expression in either surface or soluble form. HCV attachment was facilitated through a direct interaction between CD36 and HCV E1 protein, causing enhanced entry and replication. The HCV co-receptor effect of CD36 was independent of that of SR-BI. CD36 monoclonal antibodies neutralized the effect of CD36 and reduced HCV replication. CD36 inhibitor sulfo-N-succinimidyl oleate (SSO), which directly bound CD36 but not SR-BI, significantly interrupted HCV entry, and therefore inhibited HCV replication. SSO’s antiviral effect was seen only in HCV but not in other viruses. SSO in combination with known anti-HCV drugs showed additional inhibition against HCV. SSO was considerably safe in mice. Conclusively, CD36 interacts with HCV E1 and might be a co-receptor specific for HCV entry; thus, CD36 could be a potential drug target against HCV.
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120
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Buttet M, Poirier H, Traynard V, Gaire K, Tran TTT, Sundaresan S, Besnard P, Abumrad NA, Niot I. Deregulated Lipid Sensing by Intestinal CD36 in Diet-Induced Hyperinsulinemic Obese Mouse Model. PLoS One 2016; 11:e0145626. [PMID: 26727015 PMCID: PMC4703141 DOI: 10.1371/journal.pone.0145626] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/07/2015] [Indexed: 12/28/2022] Open
Abstract
The metabolic syndrome (MetS) greatly increases risk of cardiovascular disease and diabetes and is generally associated with abnormally elevated postprandial triglyceride levels. We evaluated intestinal synthesis of triglyceride-rich lipoproteins (TRL) in a mouse model of the MetS obtained by feeding a palm oil-rich high fat diet (HFD). By contrast to control mice, MetS mice secreted two populations of TRL. If the smaller size population represented 44% of total particles in the beginning of intestinal lipid absorption in MetS mice, it accounted for only 17% after 4 h due to the secretion of larger size TRL. The MetS mice displayed accentuated postprandial hypertriglyceridemia up to 3 h due to a defective TRL clearance. These alterations reflected a delay in lipid induction of genes for key proteins of TRL formation (MTP, L-FABP) and blood clearance (ApoC2). These abnormalities associated with blunted lipid sensing by CD36, which is normally required to optimize jejunal formation of large TRL. In MetS mice CD36 was not downregulated by lipid in contrast to control mice. Treatment of controls with the proteosomal inhibitor MG132, which prevented CD36 downregulation, resulted in blunted lipid-induction of MTP, L-FABP and ApoC2 gene expression, as in MetS mice. Absence of CD36 sensing was due to the hyperinsulinemia in MetS mice. Acute insulin treatment of controls before lipid administration abolished CD36 downregulation, lipid-induction of TRL genes and reduced postprandial triglycerides (TG), while streptozotocin-treatment of MetS mice restored lipid-induced CD36 degradation and TG secretion. In vitro, insulin treatment abolished CD36-mediated up-regulation of MTP in Caco-2 cells. In conclusion, HFD treatment impairs TRL formation in early stage of lipid absorption via insulin-mediated inhibition of CD36 lipid sensing. This impairment results in production of smaller TRL that are cleared slowly from the circulation, which might contribute to the reported association of CD36 variants with MetS risk.
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Affiliation(s)
- Marjorie Buttet
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Hélène Poirier
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Véronique Traynard
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Kévin Gaire
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Thi Thu Trang Tran
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Sinju Sundaresan
- Department of Medicine, Gastroenterology Division, University of Michigan, Ann Arbor, Michigan, 48109, United States of America
| | - Philippe Besnard
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Nada A. Abumrad
- Department of Medicine, Center for Human Nutrition, and Department of Cell Biology & Physiology, Washington University School of Medicine, St. Louis, Missouri, 63110, United States of America
| | - Isabelle Niot
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
- * E-mail:
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121
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Pillon NJ, Azizi PM, Li YE, Liu J, Wang C, Chan KL, Hopperton KE, Bazinet RP, Heit B, Bilan PJ, Lee WL, Klip A. Palmitate-induced inflammatory pathways in human adipose microvascular endothelial cells promote monocyte adhesion and impair insulin transcytosis. Am J Physiol Endocrinol Metab 2015; 309:E35-44. [PMID: 25944880 DOI: 10.1152/ajpendo.00611.2014] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 04/25/2015] [Indexed: 02/01/2023]
Abstract
Obesity is associated with inflammation and immune cell recruitment to adipose tissue, muscle and intima of atherosclerotic blood vessels. Obesity and hyperlipidemia are also associated with tissue insulin resistance and can compromise insulin delivery to muscle. The muscle/fat microvascular endothelium mediates insulin delivery and facilitates monocyte transmigration, yet its contribution to the consequences of hyperlipidemia is poorly understood. Using primary endothelial cells from human adipose tissue microvasculature (HAMEC), we investigated the effects of physiological levels of fatty acids on endothelial inflammation and function. Expression of cytokines and adhesion molecules was measured by RT-qPCR. Signaling pathways were evaluated by pharmacological manipulation and immunoblotting. Surface expression of adhesion molecules was determined by immunohistochemistry. THP1 monocyte interaction with HAMEC was measured by cell adhesion and migration across transwells. Insulin transcytosis was measured by total internal reflection fluorescence microscopy. Palmitate, but not palmitoleate, elevated the expression of IL-6, IL-8, TLR2 (Toll-like receptor 2), and intercellular adhesion molecule 1 (ICAM-1). HAMEC had markedly low fatty acid uptake and oxidation, and CD36 inhibition did not reverse the palmitate-induced expression of adhesion molecules, suggesting that inflammation did not arise from palmitate uptake/metabolism. Instead, inhibition of TLR4 to NF-κB signaling blunted palmitate-induced ICAM-1 expression. Importantly, palmitate-induced surface expression of ICAM-1 promoted monocyte binding and transmigration. Conversely, palmitate reduced insulin transcytosis, an effect reversed by TLR4 inhibition. In summary, palmitate activates inflammatory pathways in primary microvascular endothelial cells, impairing insulin transport and increasing monocyte transmigration. This behavior may contribute in vivo to reduced tissue insulin action and enhanced tissue infiltration by immune cells.
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Affiliation(s)
- Nicolas J Pillon
- Cell Biology Program, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Paymon M Azizi
- Cell Biology Program, the Hospital for Sick Children, Toronto, Ontario, Canada; Keenan Research Centre, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Yujin E Li
- Cell Biology Program, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jun Liu
- Cell Biology Program, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Changsen Wang
- Keenan Research Centre, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Kenny L Chan
- Cell Biology Program, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Kathryn E Hopperton
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Richard P Bazinet
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Bryan Heit
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada; and
| | - Philip J Bilan
- Cell Biology Program, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Warren L Lee
- Keenan Research Centre, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Amira Klip
- Cell Biology Program, the Hospital for Sick Children, Toronto, Ontario, Canada;
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122
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Tarhda Z, Ibrahimi A. Insight into the mechanism of lipids binding and uptake by CD36 receptor. Bioinformation 2015; 11:302-6. [PMID: 26229291 PMCID: PMC4512005 DOI: 10.6026/97320630011302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 05/28/2015] [Accepted: 06/01/2015] [Indexed: 11/23/2022] Open
Abstract
The membrane protein CD36 is a member of the class B scavenger receptor family. It plays a crucial role in some cardiovascular pathologies and metabolic diseases. Studying the mechanism of action of CD36 receptor is limited due to the absence of its tridimensional crystallized structure. The molecular docking method has allowed us to perform various simulation of the CD36 receptor interaction with their ligands involved in the development of some diseases. In this work, we predicted a tridimensional structure model of CD36 extracellular domain. In addition, we have achieved several tests of rigid and flexible docking by acting on residues proposed in previous experimental researches as essential in fixing of LFCAs. Furthermore, we have acted on regions that appear a key binding site of LFCAs. The physicoc hemical evaluation indicated the reliability of the proposed CD36 structure used for different molecular docking tests. Based on the docking outcome, we were able to propose the different steps of the mechanism allowing the interaction of fatty acids on CD36 receptor and their penetration into the cell cytoplasm. The obtained results and taking in consideration CD36 receptor as a therapeutic target will help us to suggest the mechanism by which an antagonist may inhibit this receptor by acting on its extracellular domain.
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Affiliation(s)
- Zineb Tarhda
- Biotechnology lab (MedBiotech), Faculté de Médecine et de Pharmacie de Rabat, Université Mohammed V, Rabat, Morocco
| | - Azeddine Ibrahimi
- Biotechnology lab (MedBiotech), Faculté de Médecine et de Pharmacie de Rabat, Université Mohammed V, Rabat, Morocco
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123
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Samovski D, Sun J, Pietka T, Gross RW, Eckel RH, Su X, Stahl PD, Abumrad NA. Regulation of AMPK activation by CD36 links fatty acid uptake to β-oxidation. Diabetes 2015; 64:353-9. [PMID: 25157091 PMCID: PMC4303974 DOI: 10.2337/db14-0582] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Increases in muscle energy needs activate AMPK and induce sarcolemmal recruitment of the fatty acid (FA) translocase CD36. The resulting rises in FA uptake and FA oxidation are tightly correlated, suggesting coordinated regulation. We explored the possibility that membrane CD36 signaling might influence AMPK activation. We show, using several cell types, including myocytes, that CD36 expression suppresses AMPK, keeping it quiescent, while it mediates AMPK activation by FA. These dual effects reflect the presence of CD36 in a protein complex with the AMPK kinase LKB1 (liver kinase B1) and the src kinase Fyn. This complex promotes Fyn phosphorylation of LKB1 and its nuclear sequestration, hindering LKB1 activation of AMPK. FA interaction with CD36 dissociates Fyn from the protein complex, allowing LKB1 to remain cytosolic and activate AMPK. Consistent with this, CD36(-/-) mice have constitutively active muscle and heart AMPK and enhanced FA oxidation of endogenous triglyceride stores. The molecular mechanism described, whereby CD36 suppresses AMPK, with FA binding to CD36 releasing this suppression, couples AMPK activation to FA availability and would be important for the maintenance of cellular FA homeostasis. Its dysfunction might contribute to the reported association of CD36 variants with metabolic complications of obesity in humans.
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Affiliation(s)
- Dmitri Samovski
- Department of Medicine, Center for Human Nutrition, Washington University School of Medicine in St. Louis, St. Louis, MO Department of Cell Biology & Physiology, Washington University School of Medicine in St. Louis, St. Louis, MO
| | - Jingyu Sun
- Department of Cell Biology & Physiology, Washington University School of Medicine in St. Louis, St. Louis, MO
| | - Terri Pietka
- Department of Medicine, Center for Human Nutrition, Washington University School of Medicine in St. Louis, St. Louis, MO
| | - Richard W Gross
- Department of Medicine, Center for Human Nutrition, Washington University School of Medicine in St. Louis, St. Louis, MO Department of Developmental Biology, Washington University School of Medicine in St. Louis, St. Louis, MO
| | - Robert H Eckel
- Department of Endocrinology, Metabolism and Diabetes, University of Colorado, Denver, CO
| | - Xiong Su
- Department of Biochemistry and Molecular Biology, Medical College of Soochow University, Suzhou, People's Republic of China
| | - Philip D Stahl
- Department of Cell Biology & Physiology, Washington University School of Medicine in St. Louis, St. Louis, MO
| | - Nada A Abumrad
- Department of Medicine, Center for Human Nutrition, Washington University School of Medicine in St. Louis, St. Louis, MO Department of Cell Biology & Physiology, Washington University School of Medicine in St. Louis, St. Louis, MO
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124
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Jay AG, Chen AN, Paz MA, Hung JP, Hamilton JA. CD36 binds oxidized low density lipoprotein (LDL) in a mechanism dependent upon fatty acid binding. J Biol Chem 2015; 290:4590-4603. [PMID: 25555908 DOI: 10.1074/jbc.m114.627026] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The association of unesterified fatty acid (FA) with the scavenger receptor CD36 has been actively researched, with focuses on FA and oxidized low density lipoprotein (oxLDL) uptake. CD36 has been shown to bind FA, but this interaction has been poorly characterized to date. To gain new insights into the physiological relevance of binding of FA to CD36, we characterized FA binding to the ectodomain of CD36 by the biophysical method surface plasmon resonance. Five structurally distinct FAs (saturated, monounsaturated (cis and trans), polyunsaturated, and oxidized) were pulsed across surface plasmon resonance channels, generating association and dissociation binding curves. Except for the oxidized FA HODE, all FAs bound to CD36, with rapid association and dissociation kinetics similar to HSA. Next, to elucidate the role that each FA might play in CD36-mediated oxLDL uptake, we used a fluorescent oxLDL (Dii-oxLDL) live cell assay with confocal microscopy imaging. CD36-mediated uptake in serum-free medium was very low but greatly increased when serum was present. The addition of exogenous FA in serum-free medium increased oxLDL binding and uptake to levels found with serum and affected CD36 plasma membrane distribution. Binding/uptake of oxLDL was dependent upon the FA dose, except for docosahexaenoic acid, which exhibited binding to CD36 but did not activate the uptake of oxLDL. HODE also did not affect oxLDL uptake. High affinity FA binding to CD36 and the effects of each FA on oxLDL uptake have important implications for protein conformation, binding of other ligands, functional properties of CD36, and high plasma FA levels in obesity and type 2 diabetes.
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Affiliation(s)
- Anthony G Jay
- From the Departments of Biochemistry and; Physiology and Biophysics, Boston University, Boston, Massachusetts 02118
| | - Alexander N Chen
- Physiology and Biophysics, Boston University, Boston, Massachusetts 02118
| | - Miguel A Paz
- Physiology and Biophysics, Boston University, Boston, Massachusetts 02118
| | - Justin P Hung
- Physiology and Biophysics, Boston University, Boston, Massachusetts 02118
| | - James A Hamilton
- Physiology and Biophysics, Boston University, Boston, Massachusetts 02118.
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125
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Li X, Melief E, Postupna N, Montine KS, Keene CD, Montine TJ. Prostaglandin E2 receptor subtype 2 regulation of scavenger receptor CD36 modulates microglial Aβ42 phagocytosis. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 185:230-9. [PMID: 25452117 DOI: 10.1016/j.ajpath.2014.09.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 09/14/2014] [Accepted: 09/18/2014] [Indexed: 12/18/2022]
Abstract
Recent studies underline the potential relevance of microglial innate immune activation in Alzheimer disease. Primary mouse microglia that lack prostaglandin E2 receptor subtype 2 (EP2) show decreased innate immune-mediated neurotoxicity and increased amyloid β (Aβ) peptide phagocytosis, features that were replicated in vivo. Here, we tested the hypothesis that scavenger receptor CD36 is an effector of EP2-regulated Aβ phagocytosis. CD36 expression was 143-fold greater in mouse primary microglia than in primary astrocytes. Three different means of suppressing EP2 signaling increased and an agonist of EP2 decreased CD36 expression in primary wild-type microglia. Activation of Toll-like receptor (TLR) 3, TLR4, and TLR7, but not TLR2 or TLR9, reduced primary microglial CD36 transcription and cell surface CD36 protein and reduced Aβ42 phagocytosis as well. At each step, the effects of innate immune activation on CD36 were reversed by at least 50% by an EP2 antagonist, and this partial rescue of microglia Aβ42 phagocytosis was largely mediated by CD36 activity. Finally, we showed in hippocampus of wild-type mice that innate immune activation suppressed CD36 expression by an EP2-dependent mechanism. Taken together with results of others that found brain clearance of Aβ peptides and behavioral improvements mediated by CD36 in mice, regulation of CD36-mediated Aβ phagocytosis by suppression of EP2 signaling may provide a new approach to suppressing some aspects of Alzheimer disease pathogenesis.
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Affiliation(s)
- Xianwu Li
- Department of Pathology, University of Washington, Seattle, Washington.
| | - Erica Melief
- Department of Pathology, University of Washington, Seattle, Washington
| | - Nadia Postupna
- Department of Pathology, University of Washington, Seattle, Washington
| | | | - C Dirk Keene
- Department of Pathology, University of Washington, Seattle, Washington
| | - Thomas J Montine
- Department of Pathology, University of Washington, Seattle, Washington
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126
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Pepino MY, Kuda O, Samovski D, Abumrad NA. Structure-function of CD36 and importance of fatty acid signal transduction in fat metabolism. Annu Rev Nutr 2014; 34:281-303. [PMID: 24850384 DOI: 10.1146/annurev-nutr-071812-161220] [Citation(s) in RCA: 404] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
CD36 (cluster of differentiation 36) is a scavenger receptor that functions in high-affinity tissue uptake of long-chain fatty acids (FAs) and contributes under excessive fat supply to lipid accumulation and metabolic dysfunction. This review describes recent evidence regarding the CD36 FA binding site and a potential mechanism for FA transfer. It also presents the view that CD36 and FA signaling coordinate fat utilization, a view that is based on newly identified CD36 actions that involve oral fat perception, intestinal fat absorption, secretion of the peptides cholecystokinin and secretin, regulation of hepatic lipoprotein output, activation of beta oxidation by muscle, and regulation of the production of the FA-derived bioactive eicosanoids. Thus abnormalities of fat metabolism and the associated pathology might involve dysfunction of CD36-mediated signal transduction in addition to the changes in FA uptake.
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127
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Abstract
The endothelium is often viewed solely as the barrier that prevents the penetration of circulating lipoproteins into the arterial wall. However, recent research has demonstrated that the endothelium has an important part in regulating circulating fatty acids and lipoproteins, and is in turn affected by these lipids/lipoproteins in ways that appear to have important repercussions for atherosclerosis. Thus, a number of potentially toxic lipids are produced during lipolysis of lipoproteins at the endothelial cell surface. Catabolism of triglyceride-rich lipoproteins creates free fatty acids that are readily taken up by endothelial cells, and, likely through the action of acyl-CoA synthetases, exacerbate inflammatory processes. In this article, we review how the endothelium participates in lipoprotein metabolism, how lipids alter endothelial functions, and how lipids are internalized, processed, and transported into the subendothelial space. Finally, we address the many endothelial changes that might promote atherogenesis, especially in the setting of diabetes.
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Affiliation(s)
- Ira J Goldberg
- Department of Medicine, Division of Preventive Medicine & Nutrition, Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY, 10032, USA,
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128
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Takai M, Kozai Y, Tsuzuki S, Matsuno Y, Fujioka M, Kamei K, Inagaki H, Eguchi A, Matsumura S, Inoue K, Fushiki T. Unsaturated long-chain fatty acids inhibit the binding of oxidized low-density lipoproteins to a model CD36. Biosci Biotechnol Biochem 2014; 78:238-44. [PMID: 25036676 DOI: 10.1080/09168451.2014.882750] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Transmembrane protein CD36 binds multiple ligands, including oxidized low-density lipoproteins (oxLDLs) and long-chain fatty acids (LCFAs). Our aim was to determine whether LCFAs compete with oxLDLs for binding to CD36. We addressed this issue by examining the inhibitory effect of LCFAs against the binding of Alexa-fluor-labeled oxLDLs (AFL-oxLDL) to a synthetic peptide representing the oxLDL-binding site on CD36 (3S-CD36₁₅₀₋₁₆₈). All of the unsaturated LCFAs tested, inhibited the binding of AFL-oxLDL to 3S-CD36₁₅₀₋₁₆₈, albeit to varying degrees. For instance, the concentrations required for 50% inhibition of binding for oleic, linoleic, and α-linolenic acids were 0.25, 0.97, and 1.2 mM, respectively. None of the saturated LCFAs tested (e.g. stearic acid) exhibited inhibitory effects. These results suggest that at least unsaturated LCFAs can compete with oxLDLs for binding to CD36. The study also provides information on the structural requirements of LCFAs for inhibition of oxLDLs-CD36 binding.
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Affiliation(s)
- Marie Takai
- a Laboratory of Nutrition Chemistry, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University , Kyoto , Japan
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129
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Ozdener MH, Subramaniam S, Sundaresan S, Sery O, Hashimoto T, Asakawa Y, Besnard P, Abumrad NA, Khan NA. CD36- and GPR120-mediated Ca²⁺ signaling in human taste bud cells mediates differential responses to fatty acids and is altered in obese mice. Gastroenterology 2014; 146:995-1005. [PMID: 24412488 PMCID: PMC3979457 DOI: 10.1053/j.gastro.2014.01.006] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 12/24/2013] [Accepted: 01/04/2014] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS It is important to increase our understanding of gustatory detection of dietary fat and its contribution to fat preference. We studied the roles of the fat taste receptors CD36 and GPR120 and their interactions via Ca(2+) signaling in fungiform taste bud cells (TBC). METHODS We measured Ca(2+) signaling in human TBC, transfected with small interfering RNAs against messenger RNAs encoding CD36 and GPR120 (or control small interfering RNAs). We also studied Ca(2+) signaling in TBC from CD36(-/-) mice and from wild-type lean and obese mice. Additional studies were conducted with mouse enteroendocrine cell line STC-1 that express GPR120 and stably transfected with human CD36. We measured release of serotonin and glucagon-like peptide-1 from human and mice TBC in response to CD36 and GPR120 activation. RESULTS High concentrations of linoleic acid induced Ca(2+) signaling via CD36 and GPR120 in human and mice TBC, as well as in STC-1 cells, and low concentrations induced Ca(2+) signaling via only CD36. Incubation of human and mice fungiform TBC with lineoleic acid down-regulated CD36 and up-regulated GPR120 in membrane lipid rafts. Obese mice had decreased spontaneous preference for fat. Fungiform TBC from obese mice had reduced Ca(2+) and serotonin responses, but increased release of glucagon-like peptide-1, along with reduced levels of CD36 and increased levels of GPR120 in lipid rafts. CONCLUSIONS CD36 and GPR120 have nonoverlapping roles in TBC signaling during orogustatory perception of dietary lipids; these are differentially regulated by obesity.
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Affiliation(s)
| | | | - Sinju Sundaresan
- Center for Human Nutrition and Department of Cell Biology and Physiology, Washington University, St. Louis, Missouri 63110, USA
| | - Omar Sery
- Academy of Science, Veveří 97, 602 00 Brno, Czech Republic
| | - Toshihiro Hashimoto
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, 770-8514, Japan
| | - Yoshinori Asakawa
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, 770-8514, Japan
| | | | - Nada A. Abumrad
- Center for Human Nutrition and Department of Cell Biology and Physiology, Washington University, St. Louis, Missouri 63110, USA
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130
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Tarhda Z, Semlali O, Kettani A, Moussa A, Abumrad NA, Ibrahimi A. Three Dimensional Structure Prediction of Fatty Acid Binding Site on Human Transmembrane Receptor CD36. Bioinform Biol Insights 2013; 7:369-73. [PMID: 24348024 PMCID: PMC3859822 DOI: 10.4137/bbi.s12276] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
CD36 is an integral membrane protein which is thought to have a hairpin-like structure with alpha-helices at the C and N terminals projecting through the membrane as well as a larger extracellular loop. This receptor interacts with a number of ligands including oxidized low density lipoprotein and long chain fatty acids (LCFAs). It is also implicated in lipid metabolism and heart diseases. It is therefore important to determine the 3D structure of the CD36 site involved in lipid binding. In this study, we predict the 3D structure of the fatty acid (FA) binding site [127-279 aa] of the CD36 receptor based on homology modeling with X-ray structure of Human Muscle Fatty Acid Binding Protein (PDB code: 1HMT). Qualitative and quantitative analysis of the resulting model suggests that this model was reliable and stable, taking in consideration over 97.8% of the residues in the most favored regions as well as the significant overall quality factor. Protein analysis, which relied on the secondary structure prediction of the target sequence and the comparison of 1HMT and CD36 [127-279 aa] secondary structures, led to the determination of the amino acid sequence consensus. These results also led to the identification of the functional sites on CD36 and revealed the presence of residues which may play a major role during ligand-protein interactions.
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Affiliation(s)
- Zineb Tarhda
- Medical Biotechnology lab, Pharmacology and Toxicology Lab, Faculty of Medicine and Pharmacy, University Mohammed V Souissi, Rabat, Morocco
| | - Oussama Semlali
- Medical Biotechnology lab, Pharmacology and Toxicology Lab, Faculty of Medicine and Pharmacy, University Mohammed V Souissi, Rabat, Morocco
| | - Anas Kettani
- Faculty of Science, University Ben Msik, Casablanca, Morocco
| | | | - Nada A Abumrad
- Department of Medicine, Center for Human Nutrition, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Azeddine Ibrahimi
- Medical Biotechnology lab, Pharmacology and Toxicology Lab, Faculty of Medicine and Pharmacy, University Mohammed V Souissi, Rabat, Morocco
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131
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Oro-gustatory perception of dietary lipids and calcium signaling in taste bud cells are altered in nutritionally obesity-prone Psammomys obesus. PLoS One 2013; 8:e68532. [PMID: 23936306 PMCID: PMC3731325 DOI: 10.1371/journal.pone.0068532] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 05/30/2013] [Indexed: 12/20/2022] Open
Abstract
Since the increasing prevalence of obesity is one of the major health problems of the modern era, understanding the mechanisms of oro-gustatory detection of dietary fat is critical for the prevention and treatment of obesity. We have conducted the present study on Psammomys obesus, the rodent desert gerbil which is a unique polygenic natural animal model of obesity. Our results show that obese animals exhibit a strong preference for lipid solutions in a two-bottle test. Interestingly, the expression of CD36, a lipido-receptor, in taste buds cells (TBC), isolated from circumvallate papillae, was decreased at mRNA level, but remained unaltered at protein level, in obese animals. We further studied the effects of linoleic acid (LA), a long-chain fatty acid, on the increases in free intracellular calcium (Ca2+) concentrations, [Ca2+]i, in the TBC of P. obesus. LA induced increases in [Ca2+]i, largely via CD36, from intracellular pool, followed by the opening of store-operated Ca2+ (SOC) channels in the TBC of these animals. The action of this fatty acid on the increases in [Ca2+]i was higher in obese animals than that in controls. However, the release of Ca2+ from intracellular stores, studied also by employing thapsigargin, was lower in TBC of obese animals than control rodents. In this study, we show, for the first time, that increased lipid intake and altered Ca2+ signaling in TBC are associated with obesity in Psammomys obesus.
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132
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Aly R, Maibach HI, Bagatell FK, Dittmar W, Hänel H, Falanga V, Leyden JJ, Roth HL, Stoughton RB, Willis I. Ciclopirox olamine lotion 1%: bioequivalence to ciclopirox olamine cream 1% and clinical efficacy in tinea pedis. Clin Ther 1989; 96:151-76. [PMID: 2663159 DOI: 10.1152/physrev.00002.2015] [Citation(s) in RCA: 140] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Studies were conducted to assess the bioequivalence of a new antimycotic formulation, ciclopirox olamine lotion 1%, to an established compound, ciclopirox olamine cream 1%. Results of in vitro studies, using skin samples from human cadavers and domestic pigs, demonstrated that the two formulations equally penetrate all layers of the stratum corneum and inhibit the growth of Trichophyton mentagrophytes and Candida albicans. In vivo studies in guinea pigs and in human volunteers demonstrated the comparable therapeutic efficacy of the lotion and the cream in experimental trichophytosis. In addition, a multicenter, double-blind clinical trial was undertaken to compare ciclopirox olamine lotion 1% with the vehicle alone in the treatment of patients with tinea pedis. Patients with plantar, interdigital, or vesicular tinea pedis were enrolled in the studies. Patients were treated for 28 days. Clinical and mycological responses were determined during treatment and two weeks posttreatment. Ciclopirox olamine lotion 1% was found to be significantly more effective than its vehicle in the treatment of patients with common tinea pedis. Minor localized side effects (pruritus, burning sensation) were reported in 2% of 89 patients treated with ciclopirox olamine lotion 1%. The results demonstrate the bioequivalence of ciclopirox olamine lotion 1% and ciclopirox olamine cream 1% and confirm the clinical effectiveness and safety of the lotion in the treatment of tinea pedis, a generally recalcitrant fungal infection. It is concluded that ciclopirox olamine lotion 1% can be used as an alternative to ciclopirox olamine cream 1% for treatment of tinea pedis, tinea versicolor, tinea cruris, tinea corporis, and cutaneous candidiasis when the convenience and/or cosmetic elegance of a lotion is desired.
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Affiliation(s)
- R Aly
- Department of Dermatology, University of California School of Medicine, San Francisco
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