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Fu Y, Zhao C, Lin C, Zhang B, Yan L, Zhang B, Wang P, Qiu L. Characterization and immune role of class B scavenger receptor member 1 in spotted sea bass (Lateolabrax maculatus). FISH & SHELLFISH IMMUNOLOGY 2024; 153:109811. [PMID: 39117126 DOI: 10.1016/j.fsi.2024.109811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 07/17/2024] [Accepted: 08/05/2024] [Indexed: 08/10/2024]
Abstract
Scavenger receptors (SRs) are integral to the innate immune system and function as pattern-recognition receptors that facilitate pathogen clearance and mediate anti-inflammatory responses. However, the role of SRs in the immune response of Lateolabrax maculatus against Aeromonas veronii is unclear. Here, we cloned scavenger receptor B1 from L. maculatus (LmSRB1) and performed bioinformatics analysis to study its potential functions. The open reading frame spans 1530 base pairs and encodes a 509-amino acid protein with a molecular mass of 57.44 kDa. Comparative analysis revealed high sequence conservation among fish species. Expression profiling revealed strong LmSRB1 transcription in various tissues, especially in head kidney and spleen. Following A. veronii exposure, LmSRB1 expression initially increased, peaking after 4-8 h, with a notable secondary peak at 72 h. Fluorescence in situ hybridization indicated that LmSRB1 mainly localized to the cytoplasm, and subcellular-localization studies confirmed LmSRB1 protein expression in the cytoplasm and cell membrane. Enzyme-linked immunosorbent assay data showed dose-dependent binding of LmSRB1 to A. veronii. Modulating LmSRB1 expression significantly altered the levels of IL-8, IL-1β, TRAF6, and NIK. These results highlight the crucial role of LmSRB1 in L. maculatus's innate immune response to A. veronii and offer insights into improving the management of bacterial infections in aquaculture.
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Affiliation(s)
- Yichen Fu
- College of Aqua-life Science and Technology, Shanghai Ocean University, Shanghai, China; Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Chao Zhao
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China; Sanya Tropical Fisheries Research Institute, Sanya, China
| | - Changhong Lin
- College of Aqua-life Science and Technology, Shanghai Ocean University, Shanghai, China; Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Bo Zhang
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China; Sanya Tropical Fisheries Research Institute, Sanya, China.
| | - Lulu Yan
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China; Sanya Tropical Fisheries Research Institute, Sanya, China
| | - Bo Zhang
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China; Sanya Tropical Fisheries Research Institute, Sanya, China.
| | - Pengfei Wang
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China; Sanya Tropical Fisheries Research Institute, Sanya, China
| | - Lihua Qiu
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China; Sanya Tropical Fisheries Research Institute, Sanya, China; Key Laboratory of Aquatic Genomics, Ministry of Agriculture and Rural Affairs, Chinese Academy of Fishery Science, Beijing, China.
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2
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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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3
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Hume DA, Caruso M, Keshvari S, Patkar OL, Sehgal A, Bush SJ, Summers KM, Pridans C, Irvine KM. The Mononuclear Phagocyte System of the Rat. THE JOURNAL OF IMMUNOLOGY 2021; 206:2251-2263. [PMID: 33965905 DOI: 10.4049/jimmunol.2100136] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/01/2021] [Indexed: 12/14/2022]
Abstract
The laboratory rat continues to be the model of choice for many studies of physiology, behavior, and complex human diseases. Cells of the mononuclear phagocyte system (MPS; monocytes, macrophages, and dendritic cells) are abundant residents in every tissue in the body and regulate postnatal development, homeostasis, and innate and acquired immunity. Recruitment and proliferation of MPS cells is an essential component of both initiation and resolution of inflammation. The large majority of current knowledge of MPS biology is derived from studies of inbred mice, but advances in technology and resources have eliminated many of the advantages of the mouse as a model. In this article, we review the tools available and the current state of knowledge of development, homeostasis, regulation, and diversity within the MPS of the rat.
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Affiliation(s)
- David A Hume
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Melanie Caruso
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Sahar Keshvari
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Omkar L Patkar
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Anuj Sehgal
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Stephen J Bush
- Nuffield Department of Clinical Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Kim M Summers
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Clare Pridans
- Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom.,Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Katharine M Irvine
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
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Thomas RC, Kheder R, Alaridhee H, Martin N, Stover CM. Complement Properdin Regulates the Metabolo-Inflammatory Response to a High Fat Diet. ACTA ACUST UNITED AC 2020; 56:medicina56090484. [PMID: 32971872 PMCID: PMC7558790 DOI: 10.3390/medicina56090484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 02/03/2023]
Abstract
Background and objectives: Overnutrition leads to a metabolic and inflammatory response that includes the activation of Complement. Properdin is the only amplifier of complement activation and increases the provision of complement activation products. Its absence has previously been shown to lead to increased obesity in mice on a high fat diet. The aim of this study was to determine ways in which properdin contributes to a less pronounced obese phenotype. Materials and Methods: Wild type (WT) and properdin deficient mice (KO) were fed a high-fat diet (HFD) for up to 12 weeks. Results: There was a significant increase in liver triglyceride content in the KO HFD group compared to WT on HFD. WT developed steatosis. KO had an additional inflammatory component (steatohepatitis). Analysis of AKT signalling by phosphorylation array supported a decrease in insulin sensitivity which was greater for KO than WT in liver and kidney. There was a significant decrease of C5L2 in the fat membranes of the KO HFD group compared to the WT HFD group. Circulating microparticles in KO HFD group showed lower presence of C5L2. Expression of the fatty acid transporter CD36 in adipose tissue was increased in KO on HFD and was also significantly increased in plasma of KO HFD mice compared to WT on HFD. CD36 was elevated on microparticles from KO on HFD. Ultrastructural changes consistent with obesity-associated glomerulopathy were observed for both HFD fed genotypes, but tubular strain was greater in KO. Conclusion: Our work demonstrates that complement properdin is a dominant factor in limiting the severity of obesity-associated conditions that impact on liver and kidney. The two receptors, C5L2 and CD36, are downstream of the activity exerted by properdin.
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Affiliation(s)
- Rόisín C. Thomas
- Department of Respiratory Sciences, University of Leicester, Leicester LE1 9HN, UK; (R.C.T.); (R.K.); (H.A.); (N.M.)
| | - Ramiar Kheder
- Department of Respiratory Sciences, University of Leicester, Leicester LE1 9HN, UK; (R.C.T.); (R.K.); (H.A.); (N.M.)
| | - Hasanain Alaridhee
- Department of Respiratory Sciences, University of Leicester, Leicester LE1 9HN, UK; (R.C.T.); (R.K.); (H.A.); (N.M.)
| | - Naomi Martin
- Department of Respiratory Sciences, University of Leicester, Leicester LE1 9HN, UK; (R.C.T.); (R.K.); (H.A.); (N.M.)
- Faculty of Health and Life Sciences, De Montfort University, Leicester LE1 9BH, UK
| | - Cordula M. Stover
- Department of Respiratory Sciences, University of Leicester, Leicester LE1 9HN, UK; (R.C.T.); (R.K.); (H.A.); (N.M.)
- Correspondence: ; Tel.: +44-116-2525032
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Gallic Acid Inhibits Lipid Accumulation via AMPK Pathway and Suppresses Apoptosis and Macrophage-Mediated Inflammation in Hepatocytes. Nutrients 2020; 12:nu12051479. [PMID: 32443660 PMCID: PMC7285059 DOI: 10.3390/nu12051479] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/14/2020] [Accepted: 05/18/2020] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease, sometimes ranges from simple steatosis to nonalcoholic steatohepatitis (NASH). Various hits including excessive hepatic steatosis, oxidative stress, apoptosis, and inflammation, contribute to NASH development. Gallic acid (GA), a natural polyphenol, was reported to exert a protective effect on hepatic steatosis in animal models, but the precise molecular mechanisms remain unclear. Here, we examined the effect of GA on hepatic lipid accumulation, apoptosis, and inflammatory response caused by hepatocyte–macrophage crosstalk. We demonstrated that GA attenuated palmitic acid (PA)-induced fat accumulation via the activation of AMP-activated protein kinase (AMPK) in HepG2 cells. GA also ameliorated cell viability and suppressed apoptosis-related gene expression and caspase 3/7 activity induced by PA and H2O2. In a co-culture of lipid-laden Hepa 1-6 hepatocytes and RAW 264 macrophages, GA reduced inflammatory mediator expression and induced antioxidant enzyme expression. These results indicate that GA suppresses hepatic lipid accumulation, apoptosis, and inflammation caused by the interaction between hepatocytes and macrophages. The potential effects of GA observed in our study could be effective in preventing NASH and its complications.
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6
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Jay AG, Simard JR, Huang N, Hamilton JA. SSO and other putative inhibitors of FA transport across membranes by CD36 disrupt intracellular metabolism, but do not affect FA translocation. J Lipid Res 2020; 61:790-807. [PMID: 32102800 DOI: 10.1194/jlr.ra120000648] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 02/19/2020] [Indexed: 12/19/2022] Open
Abstract
Membrane-bound proteins have been proposed to mediate the transport of long-chain FA (LCFA) transport through the plasma membrane (PM). These proposals are based largely on reports that PM transport of LCFAs can be blocked by a number of enzymes and purported inhibitors of LCFA transport. Here, using the ratiometric pH indicator (2',7'-bis-(2-carboxyethyl)-5-(and-6-)-carboxyfluorescein and acrylodated intestinal FA-binding protein-based dual fluorescence assays, we investigated the effects of nine inhibitors of the putative FA transporter protein CD36 on the binding and transmembrane movement of LCFAs. We particularly focused on sulfosuccinimidyl oleate (SSO), reported to be a competitive inhibitor of CD36-mediated LCFA transport. Using these assays in adipocytes and inhibitor-treated protein-free lipid vesicles, we demonstrate that rapid LCFA transport across model and biological membranes remains unchanged in the presence of these purported inhibitors. We have previously shown in live cells that CD36 does not accelerate the transport of unesterified LCFAs across the PM. Our present experiments indicated disruption of LCFA metabolism inside the cell within minutes upon treatment with many of the "inhibitors" previously assumed to inhibit LCFA transport across the PM. Furthermore, using confocal microscopy and a specific anti-SSO antibody, we found that numerous intracellular and PM-bound proteins are SSO-modified in addition to CD36. Our results support the hypothesis that LCFAs diffuse rapidly across biological membranes and do not require an active protein transporter for their transmembrane movement.
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Affiliation(s)
- Anthony G Jay
- Department of Physiology and Biomedical Engineering,Mayo Clinic, Rochester, MN 55905; Departments of Biochemistry,Boston University School of Medicine, Boston, MA 02118. mailto:
| | - Jeffrey R Simard
- Physiology and Biophysics,Boston University School of Medicine, Boston, MA 02118; Pharmacology and Experimental Therapeutics,Boston University School of Medicine, Boston, MA 02118
| | - Nasi Huang
- Section of Infectious Diseases Department of Medicine,Boston University School of Medicine, Boston, MA 02118
| | - James A Hamilton
- Physiology and Biophysics,Boston University School of Medicine, Boston, MA 02118
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7
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Gerbod-Giannone MC, Dallet L, Naudin G, Sahin A, Decossas M, Poussard S, Lambert O. Involvement of caveolin-1 and CD36 in native LDL endocytosis by endothelial cells. Biochim Biophys Acta Gen Subj 2019; 1863:830-838. [DOI: 10.1016/j.bbagen.2019.01.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 12/13/2018] [Accepted: 01/08/2019] [Indexed: 12/12/2022]
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8
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Li Y, Lu Z, Ru JH, Lopes-Virella MF, Lyons TJ, Huang Y. Saturated fatty acid combined with lipopolysaccharide stimulates a strong inflammatory response in hepatocytes in vivo and in vitro. Am J Physiol Endocrinol Metab 2018; 315:E745-E757. [PMID: 29989851 PMCID: PMC6293169 DOI: 10.1152/ajpendo.00015.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and consumption of high-fat diet (HFD) is a risk factor for NAFLD. The HFD not only increases intake of saturated fatty acid (SFA) but also induces metabolic endotoxemia, an HFD-associated increase in circulating lipopolysaccharide (LPS). Although it is known that SFA or LPS promote hepatic inflammation, a hallmark of NAFLD, it remains unclear how SFA in combination with LPS stimulates host inflammatory response in hepatocytes. In this study, we performed both in vivo and in vitro experiments to investigate the effect of SFA in combination with LPS on proinflammatory gene expression in hepatocytes. Our animal study showed that feeding low-density lipoprotein-deficient mice HFD enriched with SFA and injection of low-dose LPS cooperatively stimulated IL-6 expression in livers. To understand how SFA and LPS interact to promote IL-6 expression, our in vitro studies showed that palmitic acid (PA), a major SFA, and LPS exerted synergistic effect on the expression of IL-6 in hepatocytes. Furthermore, coculture of hepatocytes with macrophages resulted in a greater IL-6 expression than culture of hepatocytes without macrophages in response to the combination of PA and LPS. Finally, we observed that LPS and PA increased ceramide production by cooperatively stimulating ceramide de novo synthesis, which played an essential role in the synergistic stimulation of proinflammatory gene expression by LPS and PA. Taken together, this study showed that SFA in combination with LPS stimulated a strong inflammatory response in hepatocytes in vivo and in vitro.
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Affiliation(s)
- Yanchun Li
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine Medical University of South Carolina, South Carolina
| | - Zhongyang Lu
- Ralph H. Johnson Veterans Affairs Medical Center , Charleston, South Carolina
| | - Ji Hyun Ru
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine Medical University of South Carolina, South Carolina
| | - Maria F Lopes-Virella
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine Medical University of South Carolina, South Carolina
- Ralph H. Johnson Veterans Affairs Medical Center , Charleston, South Carolina
| | - Timothy J Lyons
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine Medical University of South Carolina, South Carolina
| | - Yan Huang
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine Medical University of South Carolina, South Carolina
- Ralph H. Johnson Veterans Affairs Medical Center , Charleston, South Carolina
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Zhang S, Lu C, Das AK, Pasupulati AK, Menon RK. Abrogation of GH action in Kupffer cells results in increased hepatic CD36 expression and exaggerated nonalcoholic fatty liver disease. Growth Horm IGF Res 2018; 42-43:74-79. [PMID: 30321786 PMCID: PMC6286732 DOI: 10.1016/j.ghir.2018.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 09/09/2018] [Accepted: 10/02/2018] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To investigate the effects of GH signaling on Kupffer cells and the resulting changes in lipid homeostasis and their underlying mechanism(s) in the livers of diet-induced obese (DIO) mice. DESIGN Male macrophage specific-growth hormone receptor knockout mice (MacGHR KO) and their litter mate controls were fed a high fat diet containing 60% calories from fat for 26 weeks. Lipid content and lipid profiles in the liver and circulation were analyzed. Expression levels of CD36 in the liver were quantified by RT-PCR and Western Blot. RESULTS Increased hepatic lipid content and abundance of long-chain unsaturated fatty acids were observed in the liver of MacGHR KO mice. These findings were associated with increased steady state levels of CD36 mRNA and protein in MacGHR KO mice when compared with their litter mate controls. CONCLUSION GH action in Kupffer cells is required for maintaining hepatic lipid homeostasis, in part via regulation of hepatic CD36 expression.
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Affiliation(s)
- Sherry Zhang
- Departments of Pediatrics & Communicable Diseases, University of Michigan, United States
| | - Chunxia Lu
- Departments of Pediatrics & Communicable Diseases, University of Michigan, United States
| | - Arun K Das
- Department of Internal Medicine, University of Michigan, United States
| | - Anil K Pasupulati
- Department of Biochemistry, University of Hyderabad, Hyderabad, India
| | - Ram K Menon
- Departments of Pediatrics & Communicable Diseases, University of Michigan, United States; Department of Molecular & Integrative Physiology, University of Michigan, United States.
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10
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Orosensory Detection of Dietary Fatty Acids Is Altered in CB₁R -/- Mice. Nutrients 2018; 10:nu10101347. [PMID: 30241419 PMCID: PMC6213063 DOI: 10.3390/nu10101347] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 09/14/2018] [Accepted: 09/18/2018] [Indexed: 12/25/2022] Open
Abstract
Obesity is one of the major public health issues, and its prevalence is steadily increasing all the world over. The endocannabinoid system (ECS) has been shown to be involved in the intake of palatable food via activation of cannabinoid 1 receptor (CB1R). However, the involvement of lingual CB1R in the orosensory perception of dietary fatty acids has never been investigated. In the present study, behavioral tests on CB1R−/− and wild type (WT) mice showed that the invalidation of Cb1r gene was associated with low preference for solutions containing rapeseed oil or a long-chain fatty acid (LCFA), such as linoleic acid (LA). Administration of rimonabant, a CB1R inverse agonist, in mice also brought about a low preference for dietary fat. No difference in CD36 and GPR120 protein expressions were observed in taste bud cells (TBC) from WT and CB1R−/− mice. However, LCFA induced a higher increase in [Ca2+]i in TBC from WT mice than that in TBC from CB1R−/− mice. TBC from CB1R−/− mice also exhibited decreased Proglucagon and Glp-1r mRNA and a low GLP-1 basal level. We report that CB1R is involved in fat taste perception via calcium signaling and GLP-1 secretion.
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11
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Liu H, Xu Y, Wang Y, Zhong S, Wang M, Lin P, Li H, Liu Z. Cd36 is a candidate lipid sensor involved in the sensory detection of fatty acid in zebrafish. Physiol Behav 2017; 182:34-39. [PMID: 28939428 DOI: 10.1016/j.physbeh.2017.09.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 08/15/2017] [Accepted: 09/17/2017] [Indexed: 11/26/2022]
Abstract
Recently more and more evidences raise the possibility for the taste system in the role of the perception of lipids in mammals, and the fatty acid receptor CD36 has been proved to be as an important candidate receptor of fat taste. Fish has different taste modality with mammals. No information was known about the function of cd36 in fish taste till now. Here, using in situ hybridization and immunofluorescence technologies, we showed that fish cd36/Cd36 localized in taste buds. Real-time PCR technology demonstrated that, in zebrafish cd36 (zcd36)-transfected cells, linoleic acid (LA) increased the expression level of tryptophan hydroxylase-1 (TPH-1), which encodes the enzyme involved in the biosynthesis of monoamine neurotransmitter of 5-HT. Moreover, the LA-induced up-regulation expression of TPH-1 was significantly curtailed by SSO, a specific inhibitor of LCFA binding to CD36, suggesting zCd36 is implicated in the LA-induced release of neurotransmitter. Importantly, we observed that zcd36 gene knockout zebrafish reduced the preference for LA contrast to wild-type zebrafish. Together, our findings indicate that Cd36 is a candidate lipid sensor involved in the sensory detection of fatty acid in zebrafish.
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Affiliation(s)
- Haiyang Liu
- College of Marine Life Science, Institute of Evolution & Marine Biodiversity, Ocean University of China, China
| | - Yanping Xu
- College of Marine Life Science, Institute of Evolution & Marine Biodiversity, Ocean University of China, China
| | - Ying Wang
- College of Marine Life Science, Institute of Evolution & Marine Biodiversity, Ocean University of China, China
| | - Shenjie Zhong
- College of Marine Life Science, Institute of Evolution & Marine Biodiversity, Ocean University of China, China
| | - Min Wang
- College of Marine Life Science, Institute of Evolution & Marine Biodiversity, Ocean University of China, China
| | - Pengyan Lin
- College of Marine Life Science, Institute of Evolution & Marine Biodiversity, Ocean University of China, China
| | - Hongyan Li
- College of Marine Life Science, Institute of Evolution & Marine Biodiversity, Ocean University of China, China
| | - Zhenhui Liu
- College of Marine Life Science, Institute of Evolution & Marine Biodiversity, Ocean University of China, China.
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Marinho TDS, Kawasaki A, Bryntesson M, Souza-Mello V, Barbosa-da-Silva S, Aguila MB, Mandarim-de-Lacerda CA. Rosuvastatin limits the activation of hepatic stellate cells in diet-induced obese mice. Hepatol Res 2017; 47:928-940. [PMID: 27653239 DOI: 10.1111/hepr.12821] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 09/07/2016] [Accepted: 09/19/2016] [Indexed: 12/14/2022]
Abstract
AIM The aim of this study was to investigate the effects of rosuvastatin in a model of diet-induced obesity and non-alcoholic fatty liver disease, with attention to the activation of hepatic stellate cells (HSCs). METHOD Male C57BL/6 mice received a control diet (C; 10% energy as lipids) or a high-fat diet (HF; 50% energy as lipids) for 12 weeks, followed by 7 weeks of treatment. Group CR received control diet + rosuvastatin; group HFR received high-fat diet + rosuvastatin. RESULTS The HF group showed higher insulin, total cholesterol, triacylglycerol, and leptin levels than the C group, all of which were significantly diminished by rosuvastatin in the HFR group. The HF group had greater steatosis and activated HSCs than the C group, whereas rosuvastatin diminished the steatosis (less 21%, P < 0.001) and significantly inhibited the activation of the HSCs in the HFR group compared to the HF group. The sterol regulatory element-binding protein-1 and the peroxisome proliferator-activated receptor (PPAR)-γ protein expressions were increased in HF animals and reduced after treatment in the HFR group. By contrast, low PPAR-α and carnitine palmitoyltransferase-1 expressions were found in the HF group, and were restored by rosuvastatin treatment in the HFR group. CONCLUSION Rosuvastatin mitigated hepatic steatosis by modulating PPAR balance, favoring PPAR-α over PPAR-γ downstream effects. The effects were accompanied by a diminishing of insulin resistance, the anti-inflammatory adipokine profile, and HSC activation, avoiding non-alcoholic fatty liver disease progression and non-alcoholic steatohepatitis onset in this model.
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Affiliation(s)
- Thatiany de Souza Marinho
- Laboratory of Morphometry, Metabolism, and Cardiovascular Disease, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Adriana Kawasaki
- Laboratory of Morphometry, Metabolism, and Cardiovascular Disease, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Vanessa Souza-Mello
- Laboratory of Morphometry, Metabolism, and Cardiovascular Disease, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Sandra Barbosa-da-Silva
- Laboratory of Morphometry, Metabolism, and Cardiovascular Disease, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcia B Aguila
- Laboratory of Morphometry, Metabolism, and Cardiovascular Disease, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carlos A Mandarim-de-Lacerda
- Laboratory of Morphometry, Metabolism, and Cardiovascular Disease, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil
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Yang N, Zhang DF, Tao Z, Li M, Zhou SM, Wang GL. Identification of a novel class B scavenger receptor homologue in Portunus trituberculatus: Molecular cloning and microbial ligand binding. FISH & SHELLFISH IMMUNOLOGY 2016; 58:73-81. [PMID: 27633673 DOI: 10.1016/j.fsi.2016.09.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 09/02/2016] [Accepted: 09/11/2016] [Indexed: 06/06/2023]
Abstract
Class B scavenger receptors (SRBs), which are present in mammals and insects, have been implicated in a wide range of functions. Herein, a novel SRB homologue, PtSRB, was cloned from the swimming crab, Portunus trituberculatus. PtSRB has 538 amino acid residues, and it consists of two transmembrane regions, a large extracellular loop, and two intracellular tails. A phylogenetic analysis showed that PtSRB distinctly clustered with Marsupenaeus japonicas SRB-1 and most Drosophila SRB homologues, including Croquemort, Peste, NinaD, and Santa Maria, but was separate from the Drosophila sensory neuron membrane protein, MjSRB-2, and all vertebrate SRBs. Real-time quantitative PCR analyses showed that the PtSRB gene was constitutively expressed in all tissues tested. When PtSRB was overexpressed in human embryonic kidney 293T cells, it was distributed in the membrane and cytoplasm. Moreover, in vitro assays showed that rPtSRB bound microbial lipopolysaccharide with low affinity, and lipoteichoic acid and peptidoglycan with high affinity. PtSRB transcripts were down-regulated after challenge with Vibrio alginolyticus or white spot syndrome virus, but not after a Candida lusitaniae challenge. This study provides valuable data for understanding the role of SRBs in the host defense against microbial pathogens, which will facilitate future studies of host-pathogen interactions in crabs.
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Affiliation(s)
- Ning Yang
- Key Laboratory of the Ministry of Education for Applied Marine Biotechnology, School of Marine Science, Ningbo University, Ningbo 315211, China; Marine Science and Engineering College, Qingdao Agricultural University, Qingdao 266109, China
| | - Dan-Feng Zhang
- Key Laboratory of the Ministry of Education for Applied Marine Biotechnology, School of Marine Science, Ningbo University, Ningbo 315211, China
| | - Zhen Tao
- Key Laboratory of the Ministry of Education for Applied Marine Biotechnology, School of Marine Science, Ningbo University, Ningbo 315211, China
| | - Meng Li
- Key Laboratory of the Ministry of Education for Applied Marine Biotechnology, School of Marine Science, Ningbo University, Ningbo 315211, China
| | - Su-Ming Zhou
- Key Laboratory of the Ministry of Education for Applied Marine Biotechnology, School of Marine Science, Ningbo University, Ningbo 315211, China.
| | - Guo-Liang Wang
- Key Laboratory of the Ministry of Education for Applied Marine Biotechnology, School of Marine Science, Ningbo University, Ningbo 315211, China.
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14
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Zheng M, Lee S, Tsuzuki S, Inoue K, Masuda D, Yamashita S, Iwanaga T. Immunohistochemical localization of fatty acid transporters and MCT1 in the sebaceous glands of mouse skin. Biomed Res 2016; 37:265-70. [PMID: 27545003 DOI: 10.2220/biomedres.37.265] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The sebaceous glands secrete sebum to protect the epidermis and hairs by the oily products. The glands express several transporters and binding proteins for the production of fatty acids and uptake of their sources. The present immunohistochemical study examined the expression and localization of CD36, MCT1, FATP4, and E-FABP in the sebaceous glands, including the meibomian and preputial glands of mice. CD36 and MCT1 in sebaceous glands were largely co-localized along the plasma membrane of secretory cells, while they were separately expressed in the glandular portion of meibomian and preputial glands. Immunoreactivities for FATP4 and E-FABP appeared diffusely in the cytoplasm of secretory cells. Genetic deletion of CD36 did not affect the immunolocalization of the three other molecules. The sebaceous glands were judged to be useful for analyzing the functions and relation of fatty acid transporters and binding proteins.
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Affiliation(s)
- Miao Zheng
- Laboratory of Histology and Cytology, Department of Anatomy, Hokkaido University Graduate School of Medicine
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15
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Lubura M, Hesse D, Kraemer M, Hallahan N, Schupp M, von Löffelholz C, Kriebel J, Rudovich N, Pfeiffer A, John C, Scheja L, Heeren J, Koliaki C, Roden M, Schürmann A. Diabetes prevalence in NZO females depends on estrogen action on liver fat content. Am J Physiol Endocrinol Metab 2015; 309:E968-80. [PMID: 26487005 DOI: 10.1152/ajpendo.00338.2015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 10/16/2015] [Indexed: 02/08/2023]
Abstract
In humans and rodents, risk of metabolic syndrome is sexually dimorphic, with an increased incidence in males. Additionally, the protective role of female gonadal hormones is ostensible, as prevalence of type 2 diabetes mellitus (T2DM) increases after menopause. Here, we investigated the influence of estrogen (E2) on the onset of T2DM in female New Zealand obese (NZO) mice. Diabetes prevalence (defined as blood glucose levels >16.6 mmol/l) of NZO females on high-fat diet (60 kcal% fat) in week 22 was 43%. This was markedly dependent on liver fat content in week 10, as detected by computed tomography. Only mice with a liver fat content >9% in week 10 plus glucose levels >10 mmol/l in week 9 developed hyperglycemia by week 22. In addition, at 11 wk, diacylglycerols were elevated in livers of diabetes-prone mice compared with controls. Hepatic expression profiles obtained from diabetes-prone and -resistant mice at 11 wk revealed increased abundance of two transcripts in diabetes-prone mice: Mogat1, which catalyzes the synthesis of diacylglycerols from monoacylglycerol and fatty acyl-CoA, and the fatty acid transporter Cd36. E2 treatment of diabetes-prone mice for 10 wk prevented any further increase in liver fat content and reduced diacylglycerols and the abundance of Mogat1 and Cd36, leading to a reduction of diabetes prevalence and an improved glucose tolerance compared with untreated mice. Our data indicate that early elevation of hepatic Cd36 and Mogat1 associates with increased production and accumulation of triglycerides and diacylglycerols, presumably resulting in reduced hepatic insulin sensitivity and leading to later onset of T2DM.
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Affiliation(s)
- Marko Lubura
- Department of Experimental Diabetology, German Institute of Human Nutrition (DIfE), Nuthetal, Germany; German Center for Diabetes Research, Neuherberg, Germany
| | - Deike Hesse
- Department of Experimental Diabetology, German Institute of Human Nutrition (DIfE), Nuthetal, Germany; German Center for Diabetes Research, Neuherberg, Germany
| | - Maria Kraemer
- Department of Experimental Diabetology, German Institute of Human Nutrition (DIfE), Nuthetal, Germany; German Center for Diabetes Research, Neuherberg, Germany
| | - Nicole Hallahan
- Department of Experimental Diabetology, German Institute of Human Nutrition (DIfE), Nuthetal, Germany; German Center for Diabetes Research, Neuherberg, Germany
| | - Michael Schupp
- Institute of Pharmacology, Center for Cardiovascular Research, Charité University Medicine, Berlin, Germany
| | - Christian von Löffelholz
- German Center for Diabetes Research, Neuherberg, Germany; Department of Clinical Nutrition, DIfE, Nuthetal, Germany; Integrated Research and Treatment Center, Center for Sepsis Control and Care, Friedrich Schiller University, and Department of Anaesthesiology and Intensive Care, Jena University Hospital, Jena, Germany
| | - Jennifer Kriebel
- German Center for Diabetes Research, Neuherberg, Germany; Research Unit of Molecular Epidemiology, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, German Center for Diabetes Research, and Institute of Epidemiology II, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg, Germany
| | - Natalia Rudovich
- German Center for Diabetes Research, Neuherberg, Germany; Department of Clinical Nutrition, DIfE, Nuthetal, Germany
| | - Andreas Pfeiffer
- German Center for Diabetes Research, Neuherberg, Germany; Department of Clinical Nutrition, DIfE, Nuthetal, Germany
| | - Clara John
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ludger Scheja
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Chryssi Koliaki
- German Center for Diabetes Research, Neuherberg, Germany; Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research, Heinrich Heine University, Düsseldorf, Germany; and Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Michael Roden
- German Center for Diabetes Research, Neuherberg, Germany; Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research, Heinrich Heine University, Düsseldorf, Germany; and Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Annette Schürmann
- Department of Experimental Diabetology, German Institute of Human Nutrition (DIfE), Nuthetal, Germany; German Center for Diabetes Research, Neuherberg, Germany;
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16
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Zhang ZQ, Shu G, Zhu XT, Wang LN, Fu Q, Hou LJ, Wang SB, Gao P, Xi QY, Zhang YL, Yu L, Lv JR, Jiang QY. Isolation and characterization of porcine circumvallate papillae cells. Acta Histochem 2014; 116:1313-22. [PMID: 25183665 DOI: 10.1016/j.acthis.2014.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 08/08/2014] [Accepted: 08/10/2014] [Indexed: 11/17/2022]
Abstract
Animal food intake is primarily controlled by appetite, which is affected by food quality, environment, and the management and status of animal health. Sensing of taste is mediated by taste receptor cells and is central to appetite. Taste receptor cells possess distinctive physiological characteristics that permit the recognition of various stimuli in foods. Thus, cultures of porcine circumvallate papillae cells provide a model for identification of the molecular and functional characteristics of taste receptor cells. In this study, we described the isolation and culture of porcine circumvallate papillae, using tissue explants and enzymatic digestion, and showed continuous viability and expression of pivotal taste marker proteins for more than 9 passages. In addition, cultured cells showed dramatic rises in intracellular calcium upon stimulation with several taste stimuli (sweet, umami, bitter, and fat). These cultures of porcine taste receptor cells provide a useful model for assessing taste preferences of pigs and may elucidate interactions between various taste stimuli.
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Affiliation(s)
- Zhi-Qi Zhang
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Gang Shu
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Xiao-Tong Zhu
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Li-Na Wang
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Qiang Fu
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Lian-Jie Hou
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Song-Bo Wang
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Ping Gao
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Qian-Yun Xi
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Yong-Liang Zhang
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Lin Yu
- DadHank (Chengdu) Biotech. Corp. Wenjiang Cross-strait Technology Industry Development Park, Chengdu 611130, China
| | - Ji-Rong Lv
- DadHank (Chengdu) Biotech. Corp. Wenjiang Cross-strait Technology Industry Development Park, Chengdu 611130, China
| | - Qing-Yan Jiang
- College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
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17
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Santamaria MH, Chen AY, Chow J, Muñoz DC, Schmid-Schönbein GW. Cleavage and reduced CD36 ectodomain density on heart and spleen macrophages in the spontaneously hypertensive rat. Microvasc Res 2014; 95:131-42. [PMID: 25172177 DOI: 10.1016/j.mvr.2014.08.004] [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] [Received: 05/19/2014] [Revised: 07/21/2014] [Accepted: 08/18/2014] [Indexed: 12/23/2022]
Abstract
Metabolic disease is accompanied by a range of cellular defects ("comorbidities") whose origin is uncertain. To investigate this pathophysiological phenomenon we used the Spontaneously Hypertensive Rat (SHR), which besides an elevated arterial blood pressure also has many other comorbidities, including a defective glucose and lipid metabolism. We have shown that this model of metabolic disease has elevated plasma matrix metalloproteinase (MMP) activity, which cleaves the extracellular domain of membrane receptors. We hypothesize here that the increased MMP activity also leads to abnormal cleavage of the scavenger receptor and fatty acid transporter CD36. To test this idea, chronic pharmaceutical MMP inhibition (CGS27023A) of the SHR and its normotensive control, the Wistar Kyoto Rat (WKY), was used to determine if inhibition of MMP activity serves to maintain CD36 receptor density and function. Surface density of CD36 on macrophages from the heart, spleen, and liver was determined in WKY, SHR, CGS-treated WKY (CGS WKY), and CGS-treated SHR (CGS SHR) by immunohistochemistry with an antibody against the CD36 ectodomain. The extracellular CD36 density was lower in SHR heart and spleen macrophages compared to that in the WKY. MMP inhibition by CGS served to restore the reduced CD36 density on SHR cardiac and splanchnic macrophages to levels of the WKY. To examine CD36 function, culture assays with murine macrophages (RAW 264.7) after incubation in fresh WKY or SHR plasma were used to test for adhesion of light-weight donor red blood cell (RBC) by CD36. This form of RBC adhesion to macrophages was reduced after incubation in SHR compared WKY plasma. Analysis of the supernatant macrophage media by Western blot shows a higher level of CD36 extracellular protein fragments following exposure to SHR plasma compared to WKY. MMP inhibition in the SHR plasma compared to untreated plasma, served to increase the RBC adhesion to macrophages and decrease the number of receptor fragments in the macrophage media. In conclusion, these studies bring to light that plasma in the SHR model of metabolic disease has an unchecked MMP degrading activity which causes cleavage of a variety of membrane receptors, including CD36, which attenuates several cellular functions typical for the metabolic disease, including RBC adhesion to the scavenger receptor CD36. In addition to other cell dysfunctions chronic MMP inhibition restores CD36 in the SHR.
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Affiliation(s)
- Marco H Santamaria
- Department of Bioengineering, Jacobs School of Engineering, Institute of Engineering in Medicine, University of California San Diego, La Jolla, CA 92093, USA.
| | - Angela Y Chen
- Department of Bioengineering, Jacobs School of Engineering, Institute of Engineering in Medicine, University of California San Diego, La Jolla, CA 92093, USA.
| | - Jason Chow
- Department of Bioengineering, Jacobs School of Engineering, Institute of Engineering in Medicine, University of California San Diego, La Jolla, CA 92093, USA.
| | - Diana C Muñoz
- Department of Bioengineering, Jacobs School of Engineering, Institute of Engineering in Medicine, University of California San Diego, La Jolla, CA 92093, USA.
| | - Geert W Schmid-Schönbein
- Department of Bioengineering, Jacobs School of Engineering, Institute of Engineering in Medicine, University of California San Diego, La Jolla, CA 92093, USA.
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18
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Bachmanov AA, Bosak NP, Lin C, Matsumoto I, Ohmoto M, Reed DR, Nelson TM. Genetics of taste receptors. Curr Pharm Des 2014; 20:2669-83. [PMID: 23886383 PMCID: PMC4764331 DOI: 10.2174/13816128113199990566] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 07/24/2013] [Indexed: 12/19/2022]
Abstract
Taste receptors function as one of the interfaces between internal and external milieus. Taste receptors for sweet and umami (T1R [taste receptor, type 1]), bitter (T2R [taste receptor, type 2]), and salty (ENaC [epithelial sodium channel]) have been discovered in the recent years, but transduction mechanisms of sour taste and ENaC-independent salt taste are still poorly understood. In addition to these five main taste qualities, the taste system detects such noncanonical "tastes" as water, fat, and complex carbohydrates, but their reception mechanisms require further research. Variations in taste receptor genes between and within vertebrate species contribute to individual and species differences in taste-related behaviors. These variations are shaped by evolutionary forces and reflect species adaptations to their chemical environments and feeding ecology. Principles of drug discovery can be applied to taste receptors as targets in order to develop novel taste compounds to satisfy demand in better artificial sweeteners, enhancers of sugar and sodium taste, and blockers of bitterness of food ingredients and oral medications.
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19
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Lu J, Huang G, Hu S, Wang Z, Guan S. 1,3-Dichloro-2-propanol induced hyperlipidemia in C57BL/6J mice via AMPK signaling pathway. Food Chem Toxicol 2013; 64:403-9. [PMID: 24333398 DOI: 10.1016/j.fct.2013.11.049] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 11/26/2013] [Accepted: 11/29/2013] [Indexed: 11/18/2022]
Abstract
1,3-Dichloro-2-propanol (1,3-DCP) is a well-known contaminant that has been detected in a wide range of foods. Dietary intake represents the greatest source of exposure to 1,3-DCP. In the study, we first found 1,3-DCP could induce hyperlipidemia in C57BL/6J mice below 1 mg/kg/day. We investigated serum lipid profile, liver total cholesterol (TC) and triglyceride (TG), histopathology of Liver and adipose tissue. The results showed 1,3-DCP dose dependently increased serum TG, TC and low-density lipoprotein cholesterol (LDL-C), decreased serum high-density lipoprotein cholesterol (HDL-C), increased relative liver weight, liver TG and TC, relative adipose tissue weight and enlarged the size of adipose cells. Because AMPK signal pathway is important in the process of lipid metabolism, we further investigated the effects of 1,3-DCP on AMPK signaling pathway in murine models. The results showed that 1,3-DCP (0.1-1 mg/kg/day) decreased p-AMPK/tAMPK ratio, p-ACC/tACC ratio, PPARα expression, but increased FAT, SREBP1, HMGCR and FAS expression. These observations indicated that 1,3-DCP induced hyperlipidemia in C57BL/6J mice at least partially through regulating AMPK signaling pathway.
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Affiliation(s)
- Jing Lu
- Department of Food Quality and Safety, Jilin University, Changchun, People's Republic of China
| | - Guoren Huang
- Department of Food Quality and Safety, Jilin University, Changchun, People's Republic of China
| | - Sizhuo Hu
- Department of Food Quality and Safety, Jilin University, Changchun, People's Republic of China
| | - Zhenning Wang
- Department of Food Quality and Safety, Jilin University, Changchun, People's Republic of China
| | - Shuang Guan
- Department of Food Quality and Safety, Jilin University, Changchun, People's Republic of China.
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20
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DiPatrizio NV, Piomelli D. The thrifty lipids: endocannabinoids and the neural control of energy conservation. Trends Neurosci 2012; 35:403-11. [PMID: 22622030 DOI: 10.1016/j.tins.2012.04.006] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 04/14/2012] [Accepted: 04/17/2012] [Indexed: 10/28/2022]
Abstract
The 'thrifty gene hypothesis' posits that evolution preferentially selects physiological mechanisms that optimize energy storage to increase survival under alternating conditions of abundance and scarcity of food. Recent experiments suggest that endocannabinoids - a class of lipid-derived mediators that activate cannabinoid receptors in many cells of the body - are key agents of energy conservation. The new evidence indicates that these compounds increase energy intake and decrease energy expenditure by controlling the activity of peripheral and central neural pathways involved in the sensing and hedonic processing of sweet and fatty foods, as well as in the storage of their energy content for future use.
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Affiliation(s)
- Nicholas V DiPatrizio
- Departments of Pharmacology, University of California, Irvine, School of Medicine, Irvine, CA, USA
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21
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Baranova IN, Vishnyakova TG, Bocharov AV, Leelahavanichkul A, Kurlander R, Chen Z, Souza ACP, Yuen PST, Star RA, Csako G, Patterson AP, Eggerman TL. Class B scavenger receptor types I and II and CD36 mediate bacterial recognition and proinflammatory signaling induced by Escherichia coli, lipopolysaccharide, and cytosolic chaperonin 60. THE JOURNAL OF IMMUNOLOGY 2011; 188:1371-80. [PMID: 22205027 DOI: 10.4049/jimmunol.1100350] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Class B scavenger receptors (SR-B) are lipoprotein receptors that also mediate pathogen recognition, phagocytosis, and clearance as well as pathogen-induced signaling. In this study we report that three members of the SR-B family, namely, CLA-1, CLA-2, and CD36, mediate recognition of bacteria not only through interaction with cell wall LPS but also with cytosolic chaperonin 60. HeLa cells stably transfected with any of these SR-Bs demonstrated markedly (3- to 5-fold) increased binding and endocytosis of Escherichia coli, LPS, and chaperonin 60 (GroEL) as revealed by both FACS analysis and confocal microscopy imaging. Increased pathogen (E. coli, LPS, and GroEL) binding to SR-Bs was also associated with the dose-dependent stimulation of cytokine secretion in the order of CD36 > CLA-2 > CLA-1 in HEK293 cells. Pathogen-induced IL-6-secretion was reduced in macrophages from CD36- and SR-BI/II-null mice by 40-50 and 30-40%, respectively. Intravenous GroEL administration increased plasma IL-6 and CXCL1 levels in mice. The cytokine responses were 40-60% lower in CD36(-/-) relative to wild-type mice, whereas increased cytokine responses were found in SR-BI/II(-/-) mice. While investigating the discrepancy of in vitro versus in vivo data in SR-BI/II deficiency, SR-BI/II(-/-) mice were found to respond to GroEL administration without increases in either plasma corticosterone or aldosterone as normally seen in wild-type mice. SR-BI/II(-/-) mice with mineralocorticoid replacement demonstrated an ∼40-50% reduction in CXCL1 and IL-6 responses. These results demonstrate that, by recognizing and mediating inflammatory signaling of both bacterial cell wall LPS and cytosolic GroEL, all three SR-B family members play important roles in innate immunity and host defense.
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Affiliation(s)
- Irina N Baranova
- Department of Laboratory Medicine, Clinical Center, National Institute of Diabetes and Digestive Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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22
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Simons PJ, Kummer JA, Luiken JJFP, Boon L. Apical CD36 immunolocalization in human and porcine taste buds from circumvallate and foliate papillae. Acta Histochem 2011; 113:839-43. [PMID: 20950842 DOI: 10.1016/j.acthis.2010.08.006] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2010] [Accepted: 08/27/2010] [Indexed: 11/16/2022]
Abstract
CD36 is the receptor for long chain fatty acids (LCFA), and is expressed in lingual taste cells from rodents. In these animals, CD36 has been proposed to play an important role in oral detection of LCFA, and subsequently, determines their dietary fat preference. Humans also seem to detect LCFA in the oral cavity, however, information on the molecular mechanism of this human orosensory LCFA recognition is currently lacking. The aim of our study was to investigate whether CD36 is also expressed in lingual human and porcine taste buds cells. Using fluorescence immunohistochemistry, apical CD36 expression was revealed in human and porcine taste bud cells from circumvallate and foliate papillae. These data suggest CD36 as the putative orosensory receptor for dietary LCFA in human, and, therefore, may be involved in our preference for fatty foods.
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Affiliation(s)
- Peter J Simons
- Department of Cell Biology, Bioceros BV, Yalelaan 46, Utrecht, The Netherlands.
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23
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Zhang XJ, Liu XM. Re: Letter to the Editor by P.J. Simons and L. Boon. Lingual CD36 and obesity: A matter of fat taste? Acta Histochem 2011. [DOI: 10.1016/j.acthis.2010.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Li R, Oteiza A, Sørensen KK, McCourt P, Olsen R, Smedsrød B, Svistounov D. Role of liver sinusoidal endothelial cells and stabilins in elimination of oxidized low-density lipoproteins. Am J Physiol Gastrointest Liver Physiol 2011; 300:G71-81. [PMID: 21030611 PMCID: PMC3025507 DOI: 10.1152/ajpgi.00215.2010] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Atherogenesis is associated with elevated levels of low-density lipoprotein (LDL) and its oxidized form (oxLDL) in the blood. The liver is an important scavenger organ for circulating oxLDLs. The present study aimed to examine endocytosis of mildly oxLDL (the major circulating form of oxLDLs) in liver sinusoidal endothelial cells (LSECs) and the involvement of the scavenger receptors stabilin-1 and stabilin-2 in this process. Freshly isolated LSECs, Kupffer cells (KCs), and stabilin-1- and stabilin-2-transfected human embryonic kidney cells were incubated with fluorescently labeled or radiolabeled oxLDLs [oxidized for 3 h (oxLDL(3)), 6 h, or 24 h (oxLDL(24))] to measure endocytosis. The intracellular localization of oxLDLs and stabilins in LSECs was examined by immunofluorescence and immunogold electron microscopy. Whereas oxLDL(24) was endocytosed both by LSECs and KCs, oxLDL(3) (mildly oxLDL) was taken up by LSECs only. The LSEC uptake of oxLDLs was significantly inhibited by the scavenger receptor ligand formaldehyde-treated serum albumin. Uptake of all modified LDLs was high in stabilin-1-transfected cells, whereas stabilin-2-transfected cells preferentially took up oxLDL(24), suggesting that stabilin-1 is a more important receptor for mildly oxLDLs than stabilin-2. Double immunogold labeling experiments in LSECs indicated interactions of stabilin-1 and stabilin-2 with oxLDL(3) on the cell surface, in coated pits, and endocytic vesicles. LSECs but not KCs endocytosed mildly oxLDL. Both stabilin-1 and stabilin-2 were involved in the LSEC endocytosis of oxLDLs, but experiments with stabilin-transfected cells pointed to stabilin-1 as the most important receptor for mildly oxLDL.
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Affiliation(s)
- Ruomei Li
- Faculty of Health Sciences, 1Vascular Biology Research Group and
| | - Ana Oteiza
- Faculty of Health Sciences, 1Vascular Biology Research Group and
| | | | - Peter McCourt
- Faculty of Health Sciences, 1Vascular Biology Research Group and
| | - Randi Olsen
- 2Department of Electron Microscopy, Institute of Medical Biology, University of Tromsø, Tromsø, Norway
| | - Bård Smedsrød
- Faculty of Health Sciences, 1Vascular Biology Research Group and
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Truong TQ, Aubin D, Falstrault L, Brodeur MR, Brissette L. SR-BI, CD36, and caveolin-1 contribute positively to cholesterol efflux in hepatic cells. Cell Biochem Funct 2010; 28:480-9. [DOI: 10.1002/cbf.1680] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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26
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Jeppesen J, Mogensen M, Prats C, Sahlin K, Madsen K, Kiens B. FAT/CD36 is localized in sarcolemma and in vesicle-like structures in subsarcolemma regions but not in mitochondria. J Lipid Res 2009; 51:1504-12. [PMID: 20023206 DOI: 10.1194/jlr.m003756] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The primary aim of the present study was to investigate in which cellular compartments fatty acid trans-locase CD36 (FAT/CD36) is localized. Intact and fully functional skeletal muscle mitochondria were isolated from lean and obese female Zucker rats and from 10 healthy male individuals. FAT/CD36 could not be detected in the isolated mitochondria, whereas the mitochondrial marker F(1)ATPase-beta was clearly detected using immunoblotting. Lack of markers for other membrane structures indicated that the mitochondria were not contaminated with membranes known to contain FAT/CD36. In addition, fluorescence immunocytochemistry was performed on single muscle fibers dissected from soleus muscle of lean and obese Zucker rats and from the vastus lateralis muscle from humans. Costaining against FAT/CD36 and MitoNEET clearly show that FAT/CD36 is highly present in sarcolemma and it also associates with some vesicle-like intracellular compartments. However, FAT/CD36 protein was not detected in mitochondrial membranes, supporting the biochemical findings. Based on the presented data, FAT/CD36 seems to be abundantly expressed in sarcolemma and in vesicle-like structures throughout the muscle cell. However, FAT/CD36 is not present in mitochondria in rat or human skeletal muscle. Thus, the functional role of FAT/CD36 in lipid transport seems primarily to be allocated to the plasma membrane in skeletal muscle.
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Affiliation(s)
- Jacob Jeppesen
- Copenhagen Muscle Research Center, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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Thomas RA, Pietrzak DC, Scicchitano MS, Thomas HC, McFarland DC, Frazier KS. Detection and characterization of circulating endothelial progenitor cells in normal rat blood. J Pharmacol Toxicol Methods 2009; 60:263-74. [PMID: 19577656 DOI: 10.1016/j.vascn.2009.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Accepted: 06/18/2009] [Indexed: 10/20/2022]
Abstract
INTRODUCTION There are currently few widely accepted noninvasive detection methods for drug-induced vascular damage. Circulating endothelial progenitor cell (EPC) enumeration in humans has recently gained attention as a potential biomarker of vascular injury/endothelial damage/dysfunction. The rat is commonly used in preclinical drug development toxicity testing and lacks consensus noninvasive methodologies for immunophenotypic identification of EPCs. Identification of immunophenotypic markers of EPCs in the rat would enable transfer of technologies used in human for potential development of biomarkers for vascular injury the rat. Therefore, the aim of this work was to develop methods to consistently identify a discreet population of EPCs from rat peripheral blood. METHODS EPCs were identified phenotypically from rat blood using cell culture, immunolabeling, fluorescence microscopy, and flow cytometry. EPCs isolated using immunolabeling coupled with magnetic separation and flow cytometric cell sorting were characterized genotypically using mRNA analysis. RESULTS A modified colony forming unit (CFU)-Hill assay confirmed existence of immature EPCs in peripheral blood. Extended in vitro culture resulted in a morphology and immunophenotype consistent with mature endothelial cells as noted by positive staining for CD31, von Willebrand factor, rat endothelial cell antigen, and negative staining for smooth muscle cell alpha-actin. The majority of the cells identified as LDL+/CD11b/c(-) did not stain positively for either vWF or CD31. EPC populations isolated using magnetic separation and cell sorting were consistently positive for PECAM1, EDN1, FLK1, VWF, ITGAD, CCR1, IP30, and MMP2 mRNA expression. Cells identified as EPCs express cell-surface and gene expression markers consistent with endothelial cells and endothelial progenitor cell populations. DISCUSSION Vascular trauma induces transient mobilization of EPCs in humans and their enumeration and characterization have been proposed as a surrogate biomarker for assessment of vascular injury. Potential exists for using rat circulating EPCs as a surrogate sampling population for biomarker development in drug-related injury in preclinical toxicity studies. A prerequisite to biomarker development is the ability to consistently identify a discreet population of EPCs from peripheral rat blood. This work describes novel methods for isolation and validation of phenotypically and genotypically consistent populations of rat EPCs from peripheral blood. These methods are well suited for potential future use in validation of enumeration and/or biomarker development methods in the rat.
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Affiliation(s)
- Roberta A Thomas
- Department of Safety Assessment, GlaxoSmithKline, King of Prussia, PA 19406, USA.
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Circulating soluble CD36 is a novel marker of liver injury in subjects with altered glucose tolerance. J Nutr Biochem 2009; 20:477-84. [DOI: 10.1016/j.jnutbio.2008.05.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 04/21/2008] [Accepted: 05/06/2008] [Indexed: 02/06/2023]
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Okamura DM, Pennathur S, Pasichnyk K, López-Guisa JM, Collins S, Febbraio M, Heinecke J, Eddy AA. CD36 regulates oxidative stress and inflammation in hypercholesterolemic CKD. J Am Soc Nephrol 2009; 20:495-505. [PMID: 19211715 DOI: 10.1681/asn.2008010009] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Scavenger receptors play a central role in atherosclerosis by processing oxidized lipoproteins and mediating their cellular effects. Recent studies suggested that the atherogenic state correlates with progression of chronic kidney disease (CKD); therefore, scavenger receptors are candidate mediators of renal fibrogenesis. Here, we investigated the role of CD36, a class B scavenger receptor, in a hypercholesterolemic model of CKD. We placed CD36-deficient mice and wild-type male mice on a high-fat Western diet for 7 to 8 wk and then performed either sham or unilateral ureteral obstruction surgery. CD36-deficient mice developed significantly less fibrosis compared with wild-type mice at days 3, 7, and 14 after obstruction. Compared with wild-type mice, CD36-deficient mice had significantly more interstitial macrophages at 7 d but not at 14 d. CD36-deficient mice exhibited reduced levels of activated NF-kappaB and oxidative stress (assessed by measuring fatty acid-derived hydroxyoctadecadienoic acid and protein carbonyl content) and decreased accumulation of interstitial myofibroblasts compared with wild-type mice. These data suggest that CD36 is a key modulator of proinflammatory and oxidative pathways that promote fibrogenesis in CKD.
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Affiliation(s)
- Daryl M Okamura
- Department of Pediatrics, Seattle Children's Research Institute, Division of Nephrology, Seattle, WA 98105, USA.
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Development of alopecia areata is associated with higher central and peripheral hypothalamic-pituitary-adrenal tone in the skin graft induced C3H/HeJ mouse model. J Invest Dermatol 2008; 129:1527-38. [PMID: 19020552 DOI: 10.1038/jid.2008.371] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The relationship of the stress response to the pathogenesis of alopecia areata (AA) was investigated by subjecting normal and skin graft-induced, AA-affected C3H/HeJ mice to light ether anesthesia or restraint stress. Plasma corticosterone (CORT), adrenocorticotropic hormone (ACTH), and estradiol (E2) levels were determined by RIA, whereas gene expression in brains, lymphoid organs, and skin was measured by quantitative RT-PCR for corticotropin-releasing hormone (Crh), arginine vasopressin (Avp), proopiomelanocortin (Pomc), glucocorticoid receptor (Nr3c1), mineralocorticoid receptor (Nr3c2), corticotropin-releasing hormone receptor types 1 and 2 (Crhr1, Crhr2), interleukin-12 (Il12), tumor necrosis factor-alpha (Tnf alpha), and estrogen receptors type-1 (Esr1) and type-2 (Esr2). AA mice had a marked increase in hypothalamic-pituitary-adrenal (HPA) tone and activity centrally, and peripherally in the skin and lymph nodes. There was also altered interaction between the adrenal and gonadal axes compared with that in normal mice. Stress further exacerbated changes in AA mouse HPA activity both centrally and peripherally. AA mice had significantly blunted CORT and ACTH responses to acute ether stress (physiological stressor) and a deficit in habituation to repeated restraint stress (psychological stressor). The positive correlation of HPA hormone levels with skin Th1 cytokines suggests that altered HPA activity may occur as a consequence of the immune response associated with AA.
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Corn oil enhancing hepatic lipid peroxidation induced by CCl4 does not aggravate liver fibrosis in rats. Food Chem Toxicol 2008; 46:2267-73. [DOI: 10.1016/j.fct.2008.03.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2007] [Revised: 02/25/2008] [Accepted: 03/04/2008] [Indexed: 01/29/2023]
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FAT/CD36 expression alone is insufficient to enhance cellular uptake of oleate. Biochem Biophys Res Commun 2008; 370:404-9. [DOI: 10.1016/j.bbrc.2008.02.164] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Accepted: 02/13/2008] [Indexed: 11/22/2022]
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Moghaddami M, Cleland LG, Radisic G, Mayrhofer G. Recruitment of dendritic cells and macrophages during T cell-mediated synovial inflammation. Arthritis Res Ther 2008; 9:R120. [PMID: 18028548 PMCID: PMC2246239 DOI: 10.1186/ar2328] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Revised: 10/08/2007] [Accepted: 11/20/2007] [Indexed: 12/31/2022] Open
Abstract
Adoptive transfer of adjuvant-induced arthritis was used in this study to examine local macrophages and dendritic cells (DCs) during T cell-mediated synovial inflammation. We studied the influx of CD11b+CD11c+ putative myeloid DCs and other non-lymphoid CD45+ cells into synovium-rich tissues (SRTs) of the affected hind paws in response to a pulse of autoreactive thoracic duct cells. Cells were prepared from the SRTs using a collagenase perfusion-digestion technique, thus allowing enumeration and phenotypic analysis by flow cytometry. Numbers of CD45+ cells increased during the first 6 days, with increases in CD45+MHC (major histocompatibility complex) II+ monocyte-like cells from as early as day 3 after transfer. In contrast, typical MHC II- monocytes, mainly of the CD4- subset, did not increase until 12 to 14 days after cell transfer, coinciding with the main influx of polymorphonuclear cells. By day 14, CD45+MHC IIhi cells constituted approximately half of all CD45+ cells in SRT. Most of the MHC IIhi cells expressed CD11c and CD11b and represented putative myeloid DCs, whereas only approximately 20% were CD163+ macrophages. Less than 5% of the MHC IIhi cells in inflamed SRT were CD11b-, setting a maximum for any influx of plasmacytoid DCs. Of the putative myeloid DCs, a third expressed CD4 and both the CD4+ and the CD4- subsets expressed the co-stimulatory molecule CD172a. Early accumulation of MHC IIhiCD11c+ monocyte-like cells during the early phase of T cell-mediated inflammation, relative to typical MHC II- blood monocytes, suggests that recruited monocytes differentiate rapidly toward the DC lineage at this stage in the disease process. However, it is possible also that the MHC IIhiCD11c+ cells originate from a specific subset of DC-like circulating mononuclear cells.
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Affiliation(s)
- Mahin Moghaddami
- Arthritis Research Laboratory, Hanson Research Institute, Institute of Medical and Veterinary Science, Frome Road, Adelaide, South Australia, 5000, Australia.
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Drover VA, Nguyen DV, Bastie CC, Darlington YF, Abumrad NA, Pessin JE, London E, Sahoo D, Phillips MC. CD36 mediates both cellular uptake of very long chain fatty acids and their intestinal absorption in mice. J Biol Chem 2008; 283:13108-15. [PMID: 18332148 DOI: 10.1074/jbc.m708086200] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The intestine has an extraordinary capacity for fatty acid (FA) absorption. Numerous candidates for a protein-mediated mechanism of dietary FA absorption have been proposed, but firm evidence for this process has remained elusive. Here we show that the scavenger receptor CD36 is required both for the uptake of very long chain FAs (VLCFAs) in cultured cells and the absorption of dietary VLCFAs in mice. We found that the fraction of CD36-dependent saturated fatty acid association/absorption in these model systems is proportional to the FA chain length and specific for fatty acids and fatty alcohols containing very long saturated acyl chains. Moreover, intestinal VLCFA absorption is completely abolished in CD36-null mice fed a high fat diet, illustrating that the predominant mechanism for VLCFA absorption is CD36-dependent. Together, these findings represent the first direct evidence for protein-facilitated FA absorption in the intestine and identify a novel therapeutic target for the treatment of diseases characterized by elevated VLCFA levels.
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Affiliation(s)
- Victor A Drover
- Department of Pharmacology, State University of New York, Stony Brook, New York 11794, USA.
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35
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Gaillard D, Laugerette F, Darcel N, El‐Yassimi A, Passilly‐Degrace P, Hichami A, Khan NA, Montmayeur J, Besnard P. The gustatory pathway is involved in CD36‐mediated orosensory perception of long‐chain fatty acids in the mouse. FASEB J 2007; 22:1458-68. [DOI: 10.1096/fj.07-8415com] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Dany Gaillard
- Physiologie de la Nutrition, UMR INSERM U 866, Ecole Nationale Supérieure de Biologie Appliquée à la Nutrition et à l'AlimentationUniversité de Bourgogne DijonFrance
| | - Fabienne Laugerette
- Physiologie de la Nutrition, UMR INSERM U 866, Ecole Nationale Supérieure de Biologie Appliquée à la Nutrition et à l'AlimentationUniversité de Bourgogne DijonFrance
- Chimioréception, Centre Européen des Sciences du Goût, UMR 5170 Centre National de la Recherche Scientifique/1214 Institut National de la Recherche Agronomique (INRA)/Université de BourgogneDijonFrance
| | - Nicolas Darcel
- Physiologie de la Nutrition et du Comportement AlimentaireInstitut National Agronomique Paris Grignon (INAPG), UMR 914 INRA/INAPGParisFrance
| | - Abdelghani El‐Yassimi
- Unité Propre de Recherche de l'Enseignement Supérieur (UPRES) 4183 Lipides et Signalisation CellulaireUniversité de BourgogneDijonFrance
| | - Patricia Passilly‐Degrace
- Physiologie de la Nutrition, UMR INSERM U 866, Ecole Nationale Supérieure de Biologie Appliquée à la Nutrition et à l'AlimentationUniversité de Bourgogne DijonFrance
| | - Aziz Hichami
- Unité Propre de Recherche de l'Enseignement Supérieur (UPRES) 4183 Lipides et Signalisation CellulaireUniversité de BourgogneDijonFrance
| | - Naim Akhtar Khan
- Unité Propre de Recherche de l'Enseignement Supérieur (UPRES) 4183 Lipides et Signalisation CellulaireUniversité de BourgogneDijonFrance
| | - Jean‐Pierre Montmayeur
- Chimioréception, Centre Européen des Sciences du Goût, UMR 5170 Centre National de la Recherche Scientifique/1214 Institut National de la Recherche Agronomique (INRA)/Université de BourgogneDijonFrance
| | - Philippe Besnard
- Physiologie de la Nutrition, UMR INSERM U 866, Ecole Nationale Supérieure de Biologie Appliquée à la Nutrition et à l'AlimentationUniversité de Bourgogne DijonFrance
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Abstract
In the past several years, tremendous progress has been achieved with the discovery and characterization of vertebrate taste receptors from the T1R and T2R families, which are involved in recognition of bitter, sweet, and umami taste stimuli. Individual differences in taste, at least in some cases, can be attributed to allelic variants of the T1R and T2R genes. Progress with understanding how T1R and T2R receptors interact with taste stimuli and with identifying their patterns of expression in taste cells sheds light on coding of taste information by the nervous system. Candidate mechanisms for detection of salts, acids, fat, complex carbohydrates, and water have also been proposed, but further studies are needed to prove their identity.
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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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38
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Yamauchi K, Ishihara A. Thyroid system-disrupting chemicals: interference with thyroid hormone binding to plasma proteins and the cellular thyroid hormone signaling pathway. REVIEWS ON ENVIRONMENTAL HEALTH 2006; 21:229-51. [PMID: 17243349 DOI: 10.1515/reveh.2006.21.4.229] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
In vertebrates, thyroid hormones are essential for post-embryonic development, such as establishing the central nervous system in mammals and metamorphosis in amphibians. The present paper summarizes the possible extra-thyroidal processes that environmental chemicals are known to or suspected to target in the thyroid hormone-signaling pathway. We describe how such chemicals interfere with thyroid-hormone-binding protein functions in plasma, thyroid-hormone-uptake system, thyroid-hormone-metabolizing enzymes, and activation or suppression of thyroid-hormone-responsive genes through thyroid-hormone receptors in mammals and amphibian tadpoles. Several organohalogens affect different aspects of the extra-thyroidal thyroid-hormone-signaling pathway but hardly affect thyroid hormone binding to receptors. Rodents and amphibian tadpoles are most sensitive to the effects of environmental chemicals during specific thyroid-hormone-related developmental windows. Possible mechanisms by which environmental chemicals exert multipotent activities beyond one hormone-signaling pathway are discussed.
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Affiliation(s)
- Kiyoshi Yamauchi
- Department of Biological Science, Faculty of Science, Shizuoka University, Suruga-ku, Shizuoka, Japan.
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McFarland DC, Zhang C, Thomas HC, T L R. Confounding effects of platelets on flow cytometric analysis and cell-sorting experiments using blood-derived cells. Cytometry A 2006; 69:86-94. [PMID: 16419063 DOI: 10.1002/cyto.a.20207] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND Flow cytometric analysis and cell-sorting of peripheral blood leukocytes is commonplace; however, platelet contamination is typically ignored during immunophenotypic analysis and sorting of blood-derived cells. METHODS Red blood cells, platelets, T & B lymphocytes, monocytes, and granulocytes were sorted from rat blood preparations. Presort enrichment was performed by differential centrifugation for all cell types. Additionally, leukocyte samples were prepared by ammonium chloride lysis of red blood cells. RESULTS Unless proper precautions were taken, significant numbers of platelets were sorted along with (nonplatelet) cells of interest. The amount of platelet contamination varied greatly from experiment to experiment with the highest level of leukocyte-platelet association observed in the neutrophil/granulocyte population in samples prepared using ammonium chloride-based red blood cell-lysing solution. CONCLUSIONS Addition of an immunophenotypic marker for platelet identification is a simple, yet prudent, measure to help evaluate the impact of platelets on immunophenotypic staining when performing flow cytometric analysis or sorting of blood-derived cells and should become a routine practice. Platelet presence in postsort fractions can be due to free platelets as well as target cell-associated platelets and both sources of contamination must be addressed.
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Affiliation(s)
- David C McFarland
- Department of Safety Assessment/Cellular Pathology, GlaxoSmithKline, King of Prussia, Pennsylvania, USA.
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40
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41
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Laugerette F, Passilly-Degrace P, Patris B, Niot I, Febbraio M, Montmayeur JP, Besnard P. CD36 involvement in orosensory detection of dietary lipids, spontaneous fat preference, and digestive secretions. J Clin Invest 2006; 115:3177-84. [PMID: 16276419 PMCID: PMC1265871 DOI: 10.1172/jci25299] [Citation(s) in RCA: 430] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Accepted: 08/23/2005] [Indexed: 12/14/2022] Open
Abstract
Rats and mice exhibit a spontaneous attraction for lipids. Such a behavior raises the possibility that an orosensory system is responsible for the detection of dietary lipids. The fatty acid transporter CD36 appears to be a plausible candidate for this function since it has a high affinity for long-chain fatty acids (LCFAs) and is found in lingual papillae in the rat. To explore this hypothesis further, experiments were conducted in rats and in wild-type and CD36-null mice. In mice, RT-PCR experiments with primers specific for candidate lipid-binding proteins revealed that only CD36 expression was restricted to lingual papillae although absent from the palatal papillae. Immunostaining studies showed a distribution of CD36 along the apical side of circumvallate taste bud cells. CD36 gene inactivation fully abolished the preference for LCFA-enriched solutions and solid diet observed in wild-type mice. Furthermore, in rats and wild-type mice with an esophageal ligation, deposition of unsaturated LCFAs onto the tongue led to a rapid and sustained rise in flux and protein content of pancreatobiliary secretions. These findings demonstrate that CD36 is involved in oral LCFA detection and raise the possibility that an alteration in the lingual fat perception may be linked to feeding dysregulation.
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Affiliation(s)
- Fabienne Laugerette
- Physiologie de la Nutrition, Ecole Nationale Supérieure de Biologie Appliquée à la Nutrition et à l'Alimentation et Centre Européen des Sciences du Goût, UMR 5170 CNRS/1214 INRA/Université de Bourgogne, Dijon, France
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42
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Abstract
Lipids as fuel for energy provision originate from different sources: albumin-bound long-chain fatty acids (LCFA) in the blood plasma, circulating very-low-density lipoproteins-triacylglycerols (VLDL-TG), fatty acids from triacylglycerol located in the muscle cell (IMTG), and possibly fatty acids liberated from adipose tissue adhering to the muscle cells. The regulation of utilization of the different lipid sources in skeletal muscle during exercise is reviewed, and the influence of diet, training, and gender is discussed. Major points deliberated are the methods utilized to measure uptake and oxidation of LCFA during exercise in humans. The role of the various lipid-binding proteins in transmembrane and cytosolic transport of lipids is considered as well as regulation of lipid entry into the mitochondria, focusing on the putative role of AMP-activated protein kinase (AMPK), acetyl CoA carboxylase (ACC), and carnitine during exercise. The possible contribution to fuel provision during exercise of circulating VLDL-TG as well as the role of IMTG is discussed from a methodological point of view. The contribution of IMTG for energy provision may not be large, covering ∼10% of total energy provision during fasting exercise in male subjects, whereas in females, IMTG may cover a larger proportion of energy delivery. Molecular mechanisms involved in breakdown of IMTG during exercise are also considered focusing on hormone-sensitive lipase (HSL). Finally, the role of lipids in development of insulin resistance in skeletal muscle, including possible molecular mechanisms involved, is discussed.
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Affiliation(s)
- Bente Kiens
- Copenhagen Muscle Research Centre, Dept. of Human Physiology, Institute of Exercise and Sports Sciences, University of Copenhagen, 13 Universitetsparken, DK-2100 Copenhagen, Denmark.
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43
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Zhu W, Smart EJ. Myristic acid stimulates endothelial nitric-oxide synthase in a CD36- and an AMP kinase-dependent manner. J Biol Chem 2005; 280:29543-50. [PMID: 15970594 DOI: 10.1074/jbc.m501238200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Dietary free fatty acids have been reported to have various effects on the endothelium including the generation of nitric oxide. The goal of the current study was to determine the mechanism whereby free fatty acid causes an increase in nitric oxide synthesis. The specific hypothesis tested was that free fatty acid association with CD36, a class B scavenger receptor, induces the activation of endothelial nitric-oxide synthase (eNOS). A human microvascular endothelial cell line and a transfected Chinese hamster ovary cell system were used to determine which free fatty acids stimulate eNOS. Surprisingly, only myristic acid, and to a lesser extent palmitic acid, stimulated eNOS. The stimulation of eNOS was dose- and time-dependent. Competition experiments with other free fatty acids and with a CD36-blocking antibody demonstrated that the effects of myristic acid on eNOS required association with CD36. Further mechanistic studies demonstrated that the effects of myristic acid on eNOS function were not dependent on PI 3-kinase, Akt kinase, or calcium. Pharmacological studies and dominant negative constructs were used to demonstrate that myristic acid/CD36 stimulation of eNOS activity was dependent on the activation of AMP kinase. These data demonstrate an unexpected link among myristic acid, CD36, AMP kinase, and eNOS activity.
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Affiliation(s)
- Weifei Zhu
- Department of Pediatrics, University of Kentucky, Lexington, 40536, USA
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44
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Lee JJ, Widmaier EP. Gene array analysis of the effects of chronic adrenocorticotropic hormone in vivo on immature rat adrenal glands. J Steroid Biochem Mol Biol 2005; 96:31-44. [PMID: 15890514 DOI: 10.1016/j.jsbmb.2005.01.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Accepted: 01/20/2005] [Indexed: 12/29/2022]
Abstract
Development of a mature adrenocortical phenotype is a critical event in the transition of mammals from fetal to postnatal life. We previously reported that the functional maturation of the adrenal glands of newborn rats is accelerated by adrenocorticotropic hormone (ACTH). We report here that chronic exposure of neonatal/juvenile rat pups to ACTH in vivo results in significant changes in expression of over 200 genes in the adrenal glands. ACTH significantly upregulated genes associated with cell signaling, gene transcription, cell migration and tissue remodeling. In addition, ACTH significantly downregulated several genes associated with de novo cholesterol biosynthesis and cholesterol trafficking. Finally, ACTH upregulated genes associated with intracellular metabolism and inactivation of glucocorticoids. The results demonstrate that the developmental effects of ACTH alter expression of a broad range of genes involved not solely in steroid synthesis, but in cellular functions related to growth and differentiation of the glands. In addition, the negative effects of ACTH on genes required for cholesterol synthesis and production of active glucocorticoids, suggests a mechanism whereby excessive production of glucocorticoids, which may have deleterious actions on developing structures like the central nervous system, is prevented.
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Affiliation(s)
- Julie J Lee
- Department of Biology, 5 Cummington Street, Boston University, Boston, MA 02215, USA
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Wilsie LC, Chanchani S, Navaratna D, Orlando RA. Cell surface heparan sulfate proteoglycans contribute to intracellular lipid accumulation in adipocytes. Lipids Health Dis 2005; 4:2. [PMID: 15636641 PMCID: PMC545935 DOI: 10.1186/1476-511x-4-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Accepted: 01/06/2005] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Transport of fatty acids within the cytosol of adipocytes and their subsequent assimilation into lipid droplets has been thoroughly investigated; however, the mechanism by which fatty acids are transported across the plasma membrane from the extracellular environment remains unclear. Since triacylglycerol-rich lipoproteins represent an abundant source of fatty acids for adipocyte utilization, we have investigated the expression levels of cell surface lipoprotein receptors and their functional contributions toward intracellular lipid accumulation; these include very low density lipoprotein receptor (VLDL-R), low density lipoprotein receptor-related protein (LRP), and heparan sulfate proteoglycans (HSPG). RESULTS We found that expression of these three lipoprotein receptors increased 5-fold, 2-fold, and 2.5-fold, respectively, during adipocyte differentiation. The major proteoglycans expressed by mature adipocytes are of high molecular weight (>500 kD) and contain both heparan and chondroitin sulfate moieties. Using ligand binding antagonists, we observed that HSPG, rather than VLDL-R or LRP, play a primary role in the uptake of DiI-labeled apoE-VLDL by mature adipocytes. In addition, inhibitors of HSPG maturation resulted in a significant reduction (>85%) in intracellular lipid accumulation. CONCLUSIONS These results suggest that cell surface HSPG is required for fatty acid transport across the plasma membrane of adipocytes.
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Affiliation(s)
- Larissa C Wilsie
- Department of Biochemistry and Molecular Biology, University of New Mexico, Health Sciences Center, 915 Camino de Salud, Albuquerque, New Mexico, 87131, USA
| | - Shree Chanchani
- Department of Biochemistry and Molecular Biology, University of New Mexico, Health Sciences Center, 915 Camino de Salud, Albuquerque, New Mexico, 87131, USA
| | - Deepti Navaratna
- Department of Biochemistry and Molecular Biology, University of New Mexico, Health Sciences Center, 915 Camino de Salud, Albuquerque, New Mexico, 87131, USA
| | - Robert A Orlando
- Department of Biochemistry and Molecular Biology, University of New Mexico, Health Sciences Center, 915 Camino de Salud, Albuquerque, New Mexico, 87131, USA
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Kiens B, Roepstorff C, Glatz JFC, Bonen A, Schjerling P, Knudsen J, Nielsen JN. Lipid-binding proteins and lipoprotein lipase activity in human skeletal muscle: influence of physical activity and gender. J Appl Physiol (1985) 2004; 97:1209-18. [PMID: 15155715 DOI: 10.1152/japplphysiol.01278.2003] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The protein and mRNA levels of several muscle lipid-binding proteins and the activity and mRNA level of muscle lipoprotein lipase (mLPL) were investigated in healthy, nonobese, nontrained (NT), moderately trained, and endurance-trained (ET) women and men. FAT/CD36 protein level was 49% higher ( P < 0.05) in women than in men, irrespective of training status, whereas FAT/CD36 mRNA was only higher ( P < 0.05) in women than in men in NT subjects (85%). Plasma membrane-bound fatty acid binding protein (FABPpm) content was higher in ET men compared with all other groups, whereas training status did not affect FABPpmcontent in women. FABPpmmRNA was higher ( P < 0.05) in NT women than in ET women and NT men. mLPL activity was not different between gender, but mLPL mRNA was 160% higher ( P < 0.001) in women than in men. mLPL activity was 48% higher ( P < 0.05) in ET than in NT subjects, irrespective of gender, in accordance with 49% higher ( P < 0.05) mLPL mRNA in ET than in NT subjects. A 90-min exercise bout induced an increase ( P < 0.05) in FAT/CD36 mRNA (∼25%) and FABPpmmRNA (∼15%) levels in all groups. The present study demonstrated that, in the NT state, women had higher muscle mRNA levels of several proteins related to muscle lipid metabolism compared with men. In the ET state, only the gender difference in mLPL mRNA persisted. FAT/CD36 protein in muscle was higher in women than in men, irrespective of training status. These findings may help explain gender differences in lipid metabolism and, furthermore, suggest that the balance between gene transcription, translation, and possibly breakdown of several proteins in muscle lipid metabolism depend on gender.
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Affiliation(s)
- Bente Kiens
- Department of Human Physiology, The Copenhagen Muscle Research Centre, Institute of Exercise and Sport Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark.
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Roepstorff C, Vistisen B, Roepstorff K, Kiens B. Regulation of plasma long-chain fatty acid oxidation in relation to uptake in human skeletal muscle during exercise. Am J Physiol Endocrinol Metab 2004; 287:E696-705. [PMID: 15186996 DOI: 10.1152/ajpendo.00001.2004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study, we investigated possible sites of regulation of long-chain fatty acid (LCFA) oxidation in contracting human skeletal muscle. Leg plasma LCFA kinetics were determined in eight healthy men during bicycling (60 min, 65% peak oxygen uptake) with either high (H-FOX) or low (L-FOX) leg fat oxidation (H-FOX: 1,098 +/- 140; L-FOX: 494 +/- 84 micromol FA/min, P < 0.001), which was achieved by manipulating preexercise muscle glycogen (H-FOX: 197 +/- 21; L-FOX: 504 +/- 25 mmol/kg dry wt, P < 0.001). Several blood metabolites and hormones were kept nearly similar between trials by allocating a preexercise meal and infusing glucose intravenously during exercise. During exercise, leg plasma LCFA fractional extraction was identical between trials (H-FOX: 17.8 +/- 1.6; L-FOX: 18.2 +/- 1.8%, not significant), suggesting similar LCFA transport capacity in muscle. On the contrary, leg plasma LCFA oxidation was 99% higher in H-FOX than in L-FOX (421 +/- 47 vs. 212 +/- 37 micromol/min, P < 0.001). Probably due to the slightly higher (P < 0.01) plasma LCFA concentration in H-FOX than in L-FOX, leg plasma LCFA uptake was nonsignificantly (P = 0.17) higher (25%) in H-FOX than in L-FOX, yet the fraction of plasma LCFA uptake oxidized was 61% higher (P < 0.05) in H-FOX than in L-FOX. Accordingly, the muscle content of several lipid-binding proteins did not differ significantly between trials, although fatty acid translocase/CD36 and caveolin-1 were elevated (P < 0.05) by the high-intensity exercise and dietary manipulation allocated on the day before the experimental trial. The present data suggest that, in contracting human skeletal muscle with different fat oxidation rates achieved by manipulating preexercise glycogen content, transsarcolemmal transport is not limiting plasma LCFA oxidation. Rather, the latter seems to be limited by intracellular regulatory mechanisms.
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Affiliation(s)
- Carsten Roepstorff
- The Copenhagen Muscle Research Centre, Institute of Exercise and Sport Sciences, Department of Human Physiology, Universitetsparken 13, DK-2100 Ø, Denmark.
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Vistisen B, Roepstorff K, Roepstorff C, Bonen A, van Deurs B, Kiens B. Sarcolemmal FAT/CD36 in human skeletal muscle colocalizes with caveolin-3 and is more abundant in type 1 than in type 2 fibers. J Lipid Res 2004; 45:603-9. [PMID: 14729862 DOI: 10.1194/jlr.m300424-jlr200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
FAT/CD36 is a transmembrane protein that is thought to facilitate cellular long-chain fatty acid uptake. However, surprisingly little is known about the localization of FAT/CD36 in human skeletal muscle. By confocal immunofluorescence microscopy, we demonstrate high FAT/CD36 expression in endothelial cells and weaker but significant FAT/CD36 expression in sarcolemma in human skeletal muscle. No apparent intracellular staining was observed in the muscle cells. There are indications in the literature that caveolae may be involved in the uptake of fatty acids, possibly as regulators of FAT/CD36 or other fatty acid transporters. We show that in sarcolemma, FAT/CD36 colocalizes with the muscle-specific caveolae marker protein caveolin-3, suggesting that caveolae may regulate cellular fatty acid uptake by FAT/CD36. Furthermore, we provide evidence that FAT/CD36 expression is significantly higher in type 1 compared with type 2 fibers, whereas caveolin-3 expression is significantly higher in type 2 fibers than in type 1 fibers.
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Affiliation(s)
- Bodil Vistisen
- Copenhagen Muscle Research Centre, Department of Medical Anatomy, University of Copenhagen, Copenhagen, Denmark
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