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Wu J, Chen X, Li R, Lu Q, Ba Y, Fang J, Liu Y, Li R, Liu Y, Wang Y, Chen J, Li Y, Huang Y. Identifying genetic determinants of sarcopenia-related traits: a Mendelian randomization study of druggable genes. Metabolism 2024; 160:155994. [PMID: 39117060 DOI: 10.1016/j.metabol.2024.155994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 07/27/2024] [Accepted: 08/03/2024] [Indexed: 08/10/2024]
Abstract
BACKGROUND Sarcopenia, characterized by progressive muscle mass and function loss, particularly affects the elderly, and leads to severe consequences such as falls and mortality. Despite its prevalence, targeted pharmacotherapies for sarcopenia are lacking. Utilizing large-sample genome-wide association studies (GWAS) data is crucial for cost-effective drug discovery. METHODS Herein, we conducted four studies to understand the putative causal effects of genetic components on muscle mass and function. Study 1 employed a two-sample Mendelian randomization (MR) on 15,944 potential druggable genes, investigating their potential causality with muscle quantity and quality in a European population (N up to 461,089). Study 2 validated MR results through sensitivity analyses and colocalization analyses. Study 3 extended validation across other European cohorts, and study 4 conducted quantitative in vivo verification. RESULTS MR analysis revealed significant causality between four genes (BLOC-1 related complex subunit 7, BORCS7; peptidase m20 domain containing 1, PM20D1; nuclear casein kinase and cyclin dependent kinase substrate 1, NUCKS1 and ubiquinol-cytochrome c reductase complex assembly factor 1, UQCC1) and muscle mass and function (p-values range 5.98 × 10-6 to 9.26 × 10-55). To be specific, BORCS7 and UQCC1 negatively regulated muscle quantity and quality, whereas enhancing PM20D1 and NUCKS1 expression showed promise in promoting muscle mass and function. Causal relationships remained robust across sensitivity analyses, with UQCC1 exhibiting notable colocalization effects (PP·H4 93.4 % to 95.8 %). Further validation and in vivo replication verified the potential causality between these genes and muscle mass as well as function. CONCLUSIONS Our druggable genome-wide MR analysis identifies BORCS7, PM20D1, NUCKS1, and UQCC1 as causally associated with muscle mass and function. These findings offer insights into the genetic basis of sarcopenia, paving the way for these genes to become promising drug targets in mitigating this debilitating condition.
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Affiliation(s)
- Jihao Wu
- Department of Endocrinology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-Sen University, Guangzhou 510080, China
| | - Xiong Chen
- Department of Urology, Sun Yat-sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120, China
| | - Ruijun Li
- Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-Sen University, Guangzhou 510080, China
| | - Qiying Lu
- Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-Sen University, Guangzhou 510080, China; Department of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-sen University, 600 Tianhe Road, Guangzhou 510630, China
| | - Yucheng Ba
- Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-Sen University, Guangzhou 510080, China
| | - Jiayun Fang
- Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-Sen University, Guangzhou 510080, China
| | - Yilin Liu
- Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-Sen University, Guangzhou 510080, China
| | - Ruijie Li
- Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-Sen University, Guangzhou 510080, China
| | - Yixuan Liu
- Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-Sen University, Guangzhou 510080, China
| | - Yiling Wang
- Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-Sen University, Guangzhou 510080, China
| | - Jinsi Chen
- Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-Sen University, Guangzhou 510080, China
| | - Yanbing Li
- Department of Endocrinology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China
| | - Yinong Huang
- Department of Endocrinology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-Sen University, Guangzhou 510080, China.
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Desai A, Yang Loureiro Z, DeSouza T, Yang Q, Solivan-Rivera J, Corvera S. PPARγ activation by lipolysis-generated ligands is required for cAMP dependent UCP1 induction in human thermogenic adipocytes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.10.607465. [PMID: 39211160 PMCID: PMC11360943 DOI: 10.1101/2024.08.10.607465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Objective The uncoupling protein 1 (UCP1) is induced in brown or "beige" adipocytes through catecholamine-induced cAMP signaling, which activates diverse transcription factors. UCP1 expression can also be enhanced by PPARγ agonists such as rosiglitazone (Rsg). However, it is unclear whether this upregulation results from de-novo differentiation of beige adipocytes from progenitor cells, or from the induction of UCP1 in pre-existing adipocytes. To explore this, we employed human adipocytes differentiated from progenitor cells and examined their acute response to Rsg, to the adenylate-cyclase activator forskolin (Fsk), or to both simultaneously. Methods Adipocytes generated from primary human progenitor cells were differentiated without exposure to PPARγ agonists, and treated for 3, 6 or 78 hours to Fsk, to Rsg, or to both simultaneously. Bulk RNASeq, RNAScope, RT-PCR, CRISPR-Cas9 mediated knockout, oxygen consumption and western blotting were used to assess cellular responses. Results UCP1 mRNA expression was induced within 3 hours of exposure to either Rsg or Fsk, indicating that Rsg's effect is independent on additional adipocyte differentiation. Although Rsg and Fsk induced distinct overall transcriptional responses, both induced genes associated with calcium metabolism, lipid droplet assembly, and mitochondrial remodeling, denoting core features of human adipocyte beiging. Unexpectedly, we found that Fsk-induced UCP1 expression was reduced by approximately 80% following CRISPR-Cas9-mediated knockout of PNPLA2 , the gene encoding the triglyceride lipase ATGL. As anticipated, ATGL knockout suppressed lipolysis; however, the associated suppression of UCP1 induction indicates that maximal cAMP-mediated UCP1 induction requires products of ATGL-catalyzed lipolysis. Supporting this, we observed that the reduction in Fsk-stimulated UCP1 induction caused by ATGL knockout was reversed by Rsg, implying that the role of lipolysis in this process is to generate natural PPARγ agonists. Conclusion UCP1 transcription is known to be stimulated by transcription factors activated downstream of cAMP-dependent protein kinases. Here we demonstrate that UCP1 transcription can also be acutely induced through PPARγ-activation. Moreover, both pathways are activated in human adipocytes in response to cAMP, synergistically inducing UCP1 expression. The stimulation of PPARγ in response to cAMP occurs as a result of the production of natural PPARγ activating ligands through ATGL-mediated lipolysis. GRAPHICAL ABSTRACT
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Reyad-Ul-Ferdous M, Gul I, Raheem MA, Pandey V, Qin P. Mitochondrial UCP1: Potential thermogenic mechanistic switch for the treatment of obesity and neurodegenerative diseases using natural and epigenetic drug candidates. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 130:155672. [PMID: 38810549 DOI: 10.1016/j.phymed.2024.155672] [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: 01/19/2024] [Revised: 02/28/2024] [Accepted: 04/21/2024] [Indexed: 05/31/2024]
Abstract
BACKGROUND Brown fat is known to provide non-shivering thermogenesis through mitochondrial uncoupling mediated by uncoupling protein 1 (UCP1). Non-shivering is not dependent on UCP2, UCP4, and BMCP1/UCP5 genes, which are distinct from UCP1 in a way that they are not constitutive uncouplers. Although they are susceptible to free fatty acid and free radical activation, their functioning has a significant impact on the performance of neurons. METHODOLOGY Using subject-specific keywords (Adipose tissue; Adipocytes; Mitochondria; Obesity; Thermogenesis; UCP's in Neurodegeneration; Alzheimer's disease; Parkinson's disease), research articles and reviews were retrieved from Web of Science, ScienceDirect, Google Scholar, and PubMed. This article includespublications published between 2018 and 2023. The drugs that upregulate UCP1 are included in the study while the drugs that do not impact UCP1 are were not included. RESULTS Neuronal UCPs have a direct impact on synaptic plasticity, neurodegenerative processes, and neurotransmission, by modulating calcium flux, mitochondrial biogenesis, local temperature, and free radical generation. Numerous significant advances in the study of neuronal UCPs and neuroprotection are still to be made. Identification of the tissue-dependent effects of UCPs is essential first. Pharmacologically targeting neuronal UCPs is a key strategy for preventing both neurodegenerative diseases and physiological aging. Given that UCP2 has activities that are tissue-specific, it will be essential to develop treatments without harmful side effects. The triggering of UCPs by CoQ, an essential cofactor, produces nigral mitochondrial uncoupling, reduces MPTP-induced toxicity, and may even decrease the course of Parkinson's disease, according to early indications. CONCLUSION Herein, we explore the potential of UCP1 as a therapeutic target for treating obesity, neurodegenerative diseases as well as a potential activator of both synthetic and natural drugs. A deeper knowledge of synaptic signaling and neurodegeneration may pave the way to new discoveries regarding the functioning and controlling of these genes.
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Affiliation(s)
- Md Reyad-Ul-Ferdous
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
| | - Ijaz Gul
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Muhammad Akmal Raheem
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Vijay Pandey
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Peiwu Qin
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
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Cui W, Yang J, Tu C, Zhang Z, Zhao H, Qiao Y, Li Y, Yang W, Lim KL, Ma Q, Zhang C, Lu L. Seipin deficiency-induced lipid dysregulation leads to hypomyelination-associated cognitive deficits via compromising oligodendrocyte precursor cell differentiation. Cell Death Dis 2024; 15:350. [PMID: 38773070 PMCID: PMC11109229 DOI: 10.1038/s41419-024-06737-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 05/05/2024] [Accepted: 05/09/2024] [Indexed: 05/23/2024]
Abstract
Seipin is one key mediator of lipid metabolism that is highly expressed in adipose tissues as well as in the brain. Lack of Seipin gene, Bscl2, leads to not only severe lipid metabolic disorders but also cognitive impairments and motor disabilities. Myelin, composed mainly of lipids, facilitates nerve transmission and is important for motor coordination and learning. Whether Seipin deficiency-leaded defects in learning and motor coordination is underlined by lipid dysregulation and its consequent myelin abnormalities remains to be elucidated. In the present study, we verified the expression of Seipin in oligodendrocytes (OLs) and their precursors, oligodendrocyte precursor cells (OPCs), and demonstrated that Seipin deficiency compromised OPC differentiation, which led to decreased OL numbers, myelin protein, myelinated fiber proportion and thickness of myelin. Deficiency of Seipin resulted in impaired spatial cognition and motor coordination in mice. Mechanistically, Seipin deficiency suppressed sphingolipid metabolism-related genes in OPCs and caused morphological abnormalities in lipid droplets (LDs), which markedly impeded OPC differentiation. Importantly, rosiglitazone, one agonist of PPAR-gamma, substantially restored phenotypes resulting from Seipin deficiency, such as aberrant LDs, reduced sphingolipids, obstructed OPC differentiation, and neurobehavioral defects. Collectively, the present study elucidated how Seipin deficiency-induced lipid dysregulation leads to neurobehavioral deficits via impairing myelination, which may pave the way for developing novel intervention strategy for treating metabolism-involved neurological disorders.
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Affiliation(s)
- Wenli Cui
- School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Jing Yang
- School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Chuanyun Tu
- School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Ziting Zhang
- School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Huifang Zhao
- School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Yan Qiao
- Analytical Instrumentation Center & State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, 030001, Shanxi, China
| | - Yanqiu Li
- Analytical Instrumentation Center & State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, 030001, Shanxi, China
| | - Wulin Yang
- Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
| | - Kah-Leong Lim
- Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore
| | - Quanhong Ma
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China.
| | - Chengwu Zhang
- School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, 030001, Shanxi, China.
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, Shanxi, China.
| | - Li Lu
- School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, 030001, Shanxi, China.
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, Shanxi, China.
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Gómez-Hernández A, de las Heras N, Gálvez BG, Fernández-Marcelo T, Fernández-Millán E, Escribano Ó. New Mediators in the Crosstalk between Different Adipose Tissues. Int J Mol Sci 2024; 25:4659. [PMID: 38731880 PMCID: PMC11083914 DOI: 10.3390/ijms25094659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 05/13/2024] Open
Abstract
Adipose tissue is a multifunctional organ that regulates many physiological processes such as energy homeostasis, nutrition, the regulation of insulin sensitivity, body temperature, and immune response. In this review, we highlight the relevance of the different mediators that control adipose tissue activity through a systematic review of the main players present in white and brown adipose tissues. Among them, inflammatory mediators secreted by the adipose tissue, such as classical adipokines and more recent ones, elements of the immune system infiltrated into the adipose tissue (certain cell types and interleukins), as well as the role of intestinal microbiota and derived metabolites, have been reviewed. Furthermore, anti-obesity mediators that promote the activation of beige adipose tissue, e.g., myokines, thyroid hormones, amino acids, and both long and micro RNAs, are exhaustively examined. Finally, we also analyze therapeutic strategies based on those mediators that have been described to date. In conclusion, novel regulators of obesity, such as microRNAs or microbiota, are being characterized and are promising tools to treat obesity in the future.
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Affiliation(s)
- Almudena Gómez-Hernández
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal, s/n, 28040 Madrid, Spain; (A.G.-H.); (B.G.G.); (T.F.-M.); (E.F.-M.)
| | - Natalia de las Heras
- Departamento de Fisiología, Facultad de Medicina, Universidad Complutense de Madrid, Plaza Ramón y Cajal, s/n, 28040 Madrid, Spain;
| | - Beatriz G. Gálvez
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal, s/n, 28040 Madrid, Spain; (A.G.-H.); (B.G.G.); (T.F.-M.); (E.F.-M.)
| | - Tamara Fernández-Marcelo
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal, s/n, 28040 Madrid, Spain; (A.G.-H.); (B.G.G.); (T.F.-M.); (E.F.-M.)
| | - Elisa Fernández-Millán
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal, s/n, 28040 Madrid, Spain; (A.G.-H.); (B.G.G.); (T.F.-M.); (E.F.-M.)
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ISCIII), 28029 Madrid, Spain
| | - Óscar Escribano
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal, s/n, 28040 Madrid, Spain; (A.G.-H.); (B.G.G.); (T.F.-M.); (E.F.-M.)
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ISCIII), 28029 Madrid, Spain
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Lee MJ, Kim J. The pathophysiology of visceral adipose tissues in cardiometabolic diseases. Biochem Pharmacol 2024; 222:116116. [PMID: 38460909 DOI: 10.1016/j.bcp.2024.116116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 02/21/2024] [Accepted: 03/06/2024] [Indexed: 03/11/2024]
Abstract
Central pattern of fat distribution, especially fat accumulation within the intraabdominal cavity increases risks for cardiometabolic diseases. Portal hypothesis combined with a pathological remodeling in visceral fat is considered the major etiological factor explaining the independent contribution of visceral obesity to cardiometabolic diseases. Excessive remodeling in visceral fat during development of obesity leads to dysfunctions in the depot, characterized by hypertrophy and death of adipocytes, hypoxia, inflammation, and fibrosis. Dysfunctional visceral fat secretes elevated levels of fatty acids, glycerol, and proinflammatory and profibrotic cytokines into the portal vein directly impacting the liver, the central regulator of systemic metabolism. These metabolic and endocrine products induce ectopic fat accumulation, insulin resistance, inflammation, and fibrosis in the liver, which in turn causes or exacerbates systemic metabolic derangements. Elucidation of underlying mechanisms that lead to the pathological remodeling and higher degree of dysfunctions in visceral adipose tissue is therefore, critical for the development of therapeutics to prevent deleterious sequelae in obesity. We review depot differences in metabolic and endocrine properties and expendabilities as well as underlying mechanisms that contribute to the pathophysiological aspects of visceral adiposity in cardiometabolic diseases. We also discuss impacts of different weight loss interventions on visceral adiposity and cardiometabolic diseases.
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Affiliation(s)
- Mi-Jeong Lee
- Department of Human Nutrition, Food and Animal Sciences, University of Hawaii at Manoa, Hawaii 96822, USA.
| | - Jeehoon Kim
- Department of Sociology, Social Work, and Criminology, Idaho State University, Idaho 83209, USA
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Lee MJ, Puri V, Fried SK. Metabolic and structural remodeling during browning of primary human adipocytes derived from omental and subcutaneous depots. Obesity (Silver Spring) 2024; 32:70-79. [PMID: 37929774 DOI: 10.1002/oby.23912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 08/04/2023] [Accepted: 08/09/2023] [Indexed: 11/07/2023]
Abstract
OBJECTIVE This study investigated remodeling of cellular metabolism and structures during browning of primary human adipocytes derived from both visceral and subcutaneous adipose tissues. Effects of glucocorticoids on the browning were also assessed. METHODS Differentiated omental and subcutaneous human adipocytes were treated with rosiglitazone, with or without dexamethasone, and expression levels of brite adipocyte markers, lipolysis, and lipid droplet and mitochondrial structures were examined. RESULTS Both omental and subcutaneous adipocytes acquired brite phenotypes upon peroxisome proliferator-activated receptor-γ agonist treatment, and dexamethasone tended to enhance the remodeling. Although rosiglitazone increased lipolysis during treatment, brite adipocytes exhibited lower basal lipolytic rates and enhanced responses to β-adrenergic agonists or atrial natriuretic peptide. Transcriptome analysis identified induction of both breakdown and biosynthesis of lipids in brite adipocytes. After 60+ days in culture, lipid droplet size increased to ~50 microns, becoming almost unilocular in control adipocytes, and after browning, they acquired paucilocular morphology, clusters of small lipid droplets (1-2 micron) surrounded by mitochondria appearing on the periphery of the central large one. CONCLUSIONS Metabolic and structural remodeling during browning of primary human adipocytes is similar to previous findings in human adipocytes in vivo, supporting their uses for mechanical studies investigating browning with translational relevance.
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Affiliation(s)
- Mi-Jeong Lee
- Department of Human Nutrition, Food and Animal Sciences, University of Hawaii at Manoa, Honolulu, Hawaii, USA
- Obesity Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Vishwajeet Puri
- Obesity Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Biomedical Sciences and Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, USA
| | - Susan K Fried
- Obesity Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine, New York, New York, USA
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Jagtap U, Paul A. UCP1 activation: Hottest target in the thermogenesis pathway to treat obesity using molecules of synthetic and natural origin. Drug Discov Today 2023; 28:103717. [PMID: 37467882 DOI: 10.1016/j.drudis.2023.103717] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 07/03/2023] [Accepted: 07/12/2023] [Indexed: 07/21/2023]
Abstract
Uncoupling protein 1 (UCP1) has been discovered as a possible target for obesity treatment because of its widespread distribution in the inner mitochondrial membrane of brown adipose tissue (BAT) and high energy expenditure capabilities to burn calories as heat. UCP1 is dormant and does not produce heat without activation as it is inhibited by purine nucleotides. However, activation of UCP1 via either direct interaction with the UCP1 protein, an increase in the expression of UCP1 genes or the physiological production of fatty acids can lead to a rise in the thermogenesis phenomenon. Hence, activation of UCP1 through small molecules of synthetic and natural origin can be considered as a promising strategy to mitigate obesity.
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Affiliation(s)
- Utkarsh Jagtap
- Laboratory of Natural Product Chemistry, Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India
| | - Atish Paul
- Laboratory of Natural Product Chemistry, Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India.
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Guerrero SC, Panettieri RA, Rastogi D. Mechanistic Links Between Obesity and Airway Pathobiology Inform Therapies for Obesity-Related Asthma. Paediatr Drugs 2023; 25:283-299. [PMID: 36656428 PMCID: PMC11071627 DOI: 10.1007/s40272-022-00554-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/27/2022] [Indexed: 01/20/2023]
Abstract
Obesity-related asthma is associated with a high disease burden and a poor response to existent asthma therapies, suggesting that it is a distinct asthma phenotype. The proposed mechanisms that contribute to obesity-related asthma include the effects of the mechanical load of obesity, adipokine perturbations, and immune dysregulation. Each of these influences airway smooth muscle function. Mechanical fat load alters airway smooth muscle stretch affecting airway wall geometry, airway smooth muscle contractility, and agonist delivery; weight loss strategies, including medically induced weight loss, counter these effects. Among the metabolic disturbances, insulin resistance and free fatty acid receptor activation influence distinct signaling pathways in the airway smooth muscle downstream of both the M2 muscarinic receptor and the β2 adrenergic receptor, such as phospholipase C and the extracellular signal-regulated kinase signaling cascade. Medications that decrease insulin resistance and dyslipidemia are associated with a lower asthma disease burden. Leptin resistance is best understood to modulate muscarinic receptors via the neural pathways but there are no specific therapies for leptin resistance. From the immune perspective, monocytes and T helper cells are involved in systemic pro-inflammatory profiles driven by obesity, notably associated with elevated levels of interleukin-6. Clinical trials on tocilizumab, an anti-interleukin antibody, are ongoing for obesity-related asthma. This armamentarium of therapies is distinct from standard asthma medications, and once investigated for its efficacy and safety among children, will serve as a novel therapeutic intervention for pediatric obesity-related asthma. Irrespective of the directionality of the association between asthma and obesity, airway-specific mechanistic studies are needed to identify additional novel therapeutic targets for obesity-related asthma.
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Affiliation(s)
- Silvia Cabrera Guerrero
- Division of Pediatric Pulmonary and Sleep Medicine, Children's National Hospital, George Washington University, 111 Michigan Ave NW, Washington, DC, 20010, USA
| | - Reynold A Panettieri
- Rutgers Institute for Translational Medicine and Science, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA
| | - Deepa Rastogi
- Division of Pediatric Pulmonary and Sleep Medicine, Children's National Hospital, George Washington University, 111 Michigan Ave NW, Washington, DC, 20010, USA.
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Raj RR, Lofquist S, Lee MJ. Remodeling of Adipose Tissues by Fatty Acids: Mechanistic Update on Browning and Thermogenesis by n-3 Polyunsaturated Fatty Acids. Pharm Res 2023; 40:467-480. [PMID: 36050546 DOI: 10.1007/s11095-022-03377-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 08/18/2022] [Indexed: 11/24/2022]
Abstract
Enhancing thermogenesis by increasing the amount and activity of brown and brite adipocytes is a potential therapeutic target for obesity and its associated diseases. Diet plays important roles in energy metabolism and a myriad of dietary components including lipids are known to regulate thermogenesis through recruitment and activation of brown and brite adipocytes. Depending on types of fatty acids (FAs), the major constituent in lipids, their health benefits differ. Long-chain polyunsaturated FAs (PUFAs), especially n-3 PUFAs remodel adipose tissues in a healthier manner with reduced inflammation and enhanced thermogenesis, while saturated FAs exhibit contrasting effects. Lipid mediators derived from FAs act as autocrine/paracrine as well as endocrine factors to regulate thermogenesis. We discuss lipid mediators that may contribute to the differential effects of FAs on adipose tissue remodeling and hence, cardiometabolic diseases. We also discuss current understanding of molecular and cellular mechanisms through which n-3 PUFAs enhance thermogenesis. Elucidating molecular details of beneficial effects of n-3 PUFAs on thermogenesis is expected to provide information that can be used for development of novel therapeutics for obesity and its associated diseases.
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Affiliation(s)
- Radha Raman Raj
- Department of Human Nutrition, Food and Animal Sciences, University of Hawaii at Manoa, 1955 East West Road, Honolulu, HI, 98622, USA
| | - Sydney Lofquist
- Department of Human Nutrition, Food and Animal Sciences, University of Hawaii at Manoa, 1955 East West Road, Honolulu, HI, 98622, USA
| | - Mi-Jeong Lee
- Department of Human Nutrition, Food and Animal Sciences, University of Hawaii at Manoa, 1955 East West Road, Honolulu, HI, 98622, USA.
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Liang XZ, Liu XC, Li S, Wen MT, Chen YR, Luo D, Xu B, Li NH, Li G. IRF8 and its related molecules as potential diagnostic biomarkers or therapeutic candidates and immune cell infiltration characteristics in steroid-induced osteonecrosis of the femoral head. J Orthop Surg Res 2023; 18:27. [PMID: 36627660 PMCID: PMC9832881 DOI: 10.1186/s13018-022-03381-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 11/02/2022] [Indexed: 01/12/2023] Open
Abstract
PURPOSE Steroid-induced osteonecrosis of the femoral head (SONFH) was a refractory orthopedic hip joint disease in the young and middle-aged people, but the pathogenesis of SONFH remained unclear. We aimed to identify the potential genes and screen potential therapeutic compounds for SONFH. METHODS The microarray was obtained for blood tissue from the GEO database, and then it identifies differentially expressed genes (DEGs). The DEGs were analyzed to obtain the differences in immune cell infiltration. The gene functional enrichment analysis of SONFH was analyzed. The PPI of DEGs was identified through the STRING database, and the cluster modules and hub genes were ascertained using MCODE and CytoHubba, and the ROC curve of hub genes was analyzed, and the tissues distribution of hub genes was understood by the HPA, Bgee and BioGPS databases. The hub genes and target miRNAs and corresponding upstream lncRNAs were predicted by TargetScan, miRDB and ENCORI database. Subsequently, we used CMap, DGIdb and L1000FWD databases to identify several potential therapeutic molecular compounds for SONFH. Finally, the AutoDockTools Vina, PyMOL and Discovery Studio were employed for molecular docking analyses between compounds and hub genes. RESULTS The microarray dataset GSE123568 was obtained related to SONFH. There were 372 DEGs including 197 upregulated genes and 175 downregulated genes by adjusted P value < 0.01 and |log2FC|> 1. Several significant GSEA enrichment analysis and biological processes and KEGG pathway associated with SONFH were identified, which were significantly related to cytoskeleton organization, nucleobase-containing compound catabolic process, NOD-like receptor signaling pathway, MAPK signaling pathway, FoxO signaling pathway, neutrophil-mediated immunity, neutrophil degranulation and neutrophil activation involved in immune response. Activated T cells CD4 memory, B cells naïve, B cells memory, T cells CD8 and T cells gamma delta might be involved in the occurrence and development of SONFH. Three cluster modules were identified in the PPI network, and eleven hub genes including FPR2, LILRB2, MNDA, CCR1, IRF8, TYROBP, TLR1, HCK, TLR8, TLR2 and CCR2 were identified by Cytohubba, which were differed in bone marrow, adipose tissue and blood, and which had good diagnostic performance in SONFH. We identified IRF8 and 10 target miRNAs that was utilized including Targetsan, miRDB and ENCORI databases and 8 corresponding upstream lncRNAs that was revealed by ENCORI database. IRF8 was detected with consistent expression by qRT-PCR. Based on the CMap, DGIdb and L1000FWD databases, the 11 small molecular compounds that were most strongly therapeutic correlated with SONFH were estradiol, genistein, domperidone, lovastatin, myricetin, fenbufen, rosiglitazone, sirolimus, phenformin, vorinostat and vinblastine. All of 11 small molecules had good binding affinity with the IRF8 in molecular docking. CONCLUSION The occurrence of SONFH was associated with a "multi-target" and "multi-pathway" pattern, especially related to immunity, and IRF8 and its noncoding RNA were closely related to the development of SONFH. The CMap, DGIdb and L1000FWD databases could be effectively used in a systematic manner to predict potential drugs for the prevention and treatment of SONFH. However, additional clinical and experimental research is warranted.
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Affiliation(s)
- Xue-Zhen Liang
- grid.479672.9Orthopaedic Microsurgery, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, 16369 Jingshi Road, Jinan City, 250014 Shandong Province China ,grid.464402.00000 0000 9459 9325The First Clinical Medical School, Shandong University of Traditional Chinese Medicine, Jinan, 250355 Shandong China
| | - Xiao-Chen Liu
- grid.479672.9Orthopaedic Microsurgery, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, 16369 Jingshi Road, Jinan City, 250014 Shandong Province China
| | - Song Li
- grid.464402.00000 0000 9459 9325Library, Shandong University of Traditional Chinese Medicine, Jinan, 250355 Shandong China
| | - Ming-Tao Wen
- grid.464402.00000 0000 9459 9325The First Clinical Medical School, Shandong University of Traditional Chinese Medicine, Jinan, 250355 Shandong China
| | - Yan-Rong Chen
- grid.479672.9Orthopaedic Microsurgery, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, 16369 Jingshi Road, Jinan City, 250014 Shandong Province China
| | - Di Luo
- grid.479672.9Orthopaedic Microsurgery, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, 16369 Jingshi Road, Jinan City, 250014 Shandong Province China
| | - Bo Xu
- grid.464402.00000 0000 9459 9325The First Clinical Medical School, Shandong University of Traditional Chinese Medicine, Jinan, 250355 Shandong China
| | - Nian-Hu Li
- grid.464402.00000 0000 9459 9325The First Clinical Medical School, Shandong University of Traditional Chinese Medicine, Jinan, 250355 Shandong China ,grid.479672.9Spinal Orthopedics, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, 16369 Jingshi Road, Jinan City, 250014 Shandong Province China
| | - Gang Li
- grid.479672.9Orthopaedic Microsurgery, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, 16369 Jingshi Road, Jinan City, 250014 Shandong Province China ,grid.464402.00000 0000 9459 9325The First Clinical Medical School, Shandong University of Traditional Chinese Medicine, Jinan, 250355 Shandong China
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Gou W, Wei H, Swaby L, Green E, Wang H. Deletion of Spinophilin Promotes White Adipocyte Browning. Pharmaceuticals (Basel) 2023; 16:91. [PMID: 36678589 PMCID: PMC9864510 DOI: 10.3390/ph16010091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/05/2023] [Accepted: 01/05/2023] [Indexed: 01/11/2023] Open
Abstract
Browning of white adipose tissue (WAT) is suggested as a promising therapeutic approach to induce energy expenditure and counteract obesity and its associated complications. Systemic depletion of spinophilin (SPL) increases metabolism and improves energy balance in mice. In this study, we explored the mechanistic insight of SPL action in WAT browning. Gene expression and mitochondria tracker staining showed that visceral white adipose tissue (vWAT) harvested from SPL KO mice had a higher expression of classic browning-related genes, including uncoupling protein 1 (UCP1), Cell death inducing DFFA like effector A (CIDEA) and PR domain containing 16 (PRDM16), as well as a higher mtDNA level compared to vWAT from wild type (WT) control mice. When adipogenesis was induced in pre-adipocytes harvested from KO and WT mice ex vivo using the PPAR-γ agonist rosiglitazone (Rosi), SPL KO cells showed increased browning marker gene expression and mitochondria function compared to cells from WT mice. Increased PPAR-γ protein expression and nucleus retention in vWAT from SPL KO mice after Rosi treatment were also observed. The effect of SPL on vWAT browning was further confirmed in vivo when WT and KO mice were treated with Rosi. As a result, SPL KO mice lost body weight, which was associated with increased expression of browning maker genes in vWAT. In summary, our data demonstrate the critical role of SPL in the regulation of WAT browning.
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Affiliation(s)
- Wenyu Gou
- Department of Surgery, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Hua Wei
- Department of Surgery, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Lindsay Swaby
- Department of Surgery, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Erica Green
- Department of Surgery, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Hongjun Wang
- Department of Surgery, Medical University of South Carolina, Charleston, SC 29425, USA
- Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC 29401, USA
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13
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Lin C, He X, Chen X, Liu L, Guan H, Xiao H, Li Y. miR-1275 Inhibits Human Omental Adipose-Derived Stem Cells Differentiation Toward the Beige Phenotype via PRDM16. Stem Cells Dev 2022; 31:799-809. [PMID: 36128801 DOI: 10.1089/scd.2022.0176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Beige adipocytes have recently attracted attention for their potential as new therapeutic targets in the management of obesity and related metabolic disorders. MicroRNAs (miRNAs) have been reported as transcriptional regulators or biomarkers of brown and beige adipogenesis. Nevertheless, the effects of miRNAs involved in beige differentiation of human visceral adipocytes remain to be investigated. In this study, microarray screening showed that miR-1275 was significantly decreased during the differentiation of beige adipocytes induced by human omental adipose-derived stem cells (hASCs). Overexpression of miR-1275 suppressed the "brown-like" differentiation of hASCs by inhibiting the key transcriptional factor PR domain containing 16 (PRDM16) without affecting the proliferation. Adipogenesis and mitochondrial biogenesis of beige adipocytes derived from hASCs were impaired by miR-1275 overexpression. The regulatory effect of miR-1275 was determined by direct binding to the 3'-untranslated region of PRDM16, which was demonstrated by a dual-luciferase assay. Taken together, this study identified miR-1275 as a negative regulator of beige cell development in hASCs by inhibiting PRDM16. Thus, miR-1275 might be a potential target in the management of visceral obesity and related metabolic diseases.
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Affiliation(s)
- Chenhong Lin
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Xiaoying He
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Xueying Chen
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Liehua Liu
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Hongyu Guan
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Haipeng Xiao
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Yanbing Li
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
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AlZaim I, Eid AH, Abd-Elrahman KS, El-Yazbi AF. Adipose Tissue Mitochondrial Dysfunction and Cardiometabolic Diseases: On the Search for Novel Molecular Targets. Biochem Pharmacol 2022; 206:115337. [DOI: 10.1016/j.bcp.2022.115337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 10/17/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022]
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15
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Preventing White Adipocyte Browning during Differentiation In Vitro: The Effect of Differentiation Protocols on Metabolic and Mitochondrial Phenotypes. Stem Cells Int 2022; 2022:3308194. [PMID: 35422865 PMCID: PMC9005291 DOI: 10.1155/2022/3308194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 03/01/2022] [Indexed: 11/29/2022] Open
Abstract
Mitochondrial dysfunction in white adipose tissue is strongly associated with obesity and its metabolic complications, which are important health challenges worldwide. Human adipose-derived stromal/stem cells (hASCs) are a promising tool to investigate the underlying mechanisms of such mitochondrial dysfunction and to subsequently provide knowledge for the development of treatments for obesity-related pathologies. A substantial obstacle in using hASCs is that the key compounds for adipogenic differentiation in vitro increase mitochondrial uncoupling, biogenesis, and activity, which are the signature features of brown adipocytes, thus altering the white adipocyte phenotype towards brown-like cells. Additionally, commonly used protocols for hASC adipogenic differentiation exhibit high variation in their composition of media, and a systematic comparison of their effect on mitochondria is missing. Here, we compared the five widely used adipogenic differentiation protocols for their effect on metabolic and mitochondrial phenotypes to identify a protocol that enables in vitro differentiation of white adipocytes and can more faithfully recapitulate the white adipocyte phenotype observed in human adipose tissue. We developed a workflow that included functional assays and morphological analysis of mitochondria and lipid droplets. We observed that triiodothyronine- or indomethacin-containing media and commercially available adipogenic media induced browning during in vitro differentiation of white adipocytes. However, the differentiation protocol containing 1 μM of the peroxisome proliferator-activated receptor gamma (PPARγ) agonist rosiglitazone prevented the browning effect and would be proposed for adipogenic differentiation protocol for hASCs to induce a white adipocyte phenotype. Preserving the white adipocyte phenotype in vitro is a crucial step for the study of obesity and associated metabolic diseases, adipose tissue pathologies, such as lipodystrophies, possible therapeutic compounds, and basic adipose tissue physiology.
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16
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Xie J, Liu H, Wandi Y, Ge S, Jin Z, Zheng M, Dan C, Liu M, Liu J. Zeaxanthin Remodels Cytoplasmic Lipid Droplets via β3-Adrenergic Receptor Signaling and Enhances Perilipin 5-Mediated Lipid Droplet–Mitochondria Interactions in Adipocytes. Food Funct 2022; 13:8892-8906. [DOI: 10.1039/d2fo01094a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cytoplasmic lipid droplets (LDs), which are remarkably dynamic, neutral lipid storage organelles, play fundamental roles in lipid metabolism and energy homeostasis. Both the dynamic remodeling of LDs and LD–mitochondria interactions...
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17
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Acín-Perez R, Petcherski A, Veliova M, Benador IY, Assali EA, Colleluori G, Cinti S, Brownstein AJ, Baghdasarian S, Livhits MJ, Yeh MW, Krishnan KC, Vergnes L, Winn NC, Padilla J, Liesa M, Sacks HS, Shirihai OS. Recruitment and remodeling of peridroplet mitochondria in human adipose tissue. Redox Biol 2021; 46:102087. [PMID: 34411987 PMCID: PMC8377484 DOI: 10.1016/j.redox.2021.102087] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/21/2021] [Accepted: 07/27/2021] [Indexed: 01/31/2023] Open
Abstract
Beige adipocyte mitochondria contribute to thermogenesis by uncoupling and by ATP-consuming futile cycles. Since uncoupling may inhibit ATP synthesis, it is expected that expenditure through ATP synthesis is segregated to a disparate population of mitochondria. Recent studies in mouse brown adipocytes identified peridroplet mitochondria (PDM) as having greater ATP synthesis and pyruvate oxidation capacities, while cytoplasmic mitochondria have increased fatty acid oxidation and uncoupling capacities. However, the occurrence of PDM in humans and the processes that result in their expansion have not been elucidated. Here, we describe a novel high-throughput assay to quantify PDM that is successfully applied to white adipose tissue from mice and humans. Using this approach, we found that PDM content varies between white and brown fat in both species. We used adipose tissue from pheochromocytoma (Pheo) patients as a model of white adipose tissue browning, which is characterized by an increase in the capacity for energy expenditure. In contrast with control subjects, PDM content was robustly increased in the periadrenal fat of Pheo patients. Remarkably, bioenergetic changes associated with browning were primarily localized to PDM compared to cytoplasmic mitochondria (CM). PDM isolated from periadrenal fat of Pheo patients had increased ATP-linked respiration, Complex IV content and activity, and maximal respiratory capacity. We found similar changes in a mouse model of re-browning where PDM content in whitened brown adipose tissue was increased upon re-browning induced by decreased housing temperature. Taken together, this study demonstrates the existence of PDM as a separate functional entity in humans and that browning in both mice and humans is associated with a robust expansion of peri-droplet mitochondria characterized by increased ATP synthesis linked respiration.
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Affiliation(s)
- Rebeca Acín-Perez
- Department of Medicine, Endocrinology, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Anton Petcherski
- Department of Medicine, Endocrinology, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Michaela Veliova
- Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA, 90095, USA
| | - Ilan Y Benador
- Department of Medicine, Endocrinology, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Nutrition and Metabolism, Graduate Medical Sciences, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Essam A Assali
- Department of Medicine, Endocrinology, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Department of Clinical Biochemistry, School of Medicine, Ben Gurion University of The Negev, Beer-Sheva, Israel
| | - Georgia Colleluori
- Department of Experimental and Clinical Medicine, Center of Obesity, Marche Polytechnic University, Ancona, 60020, Italy
| | - Saverio Cinti
- Department of Experimental and Clinical Medicine, Center of Obesity, Marche Polytechnic University, Ancona, 60020, Italy
| | - Alexandra J Brownstein
- Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Molecular Cellular Integrative Physiology, University of California, Los Angeles, CA, 90095, USA
| | - Siyouneh Baghdasarian
- Department of Medicine, Endocrinology, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Masha J Livhits
- Section of Endocrine Surgery, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Michael W Yeh
- Section of Endocrine Surgery, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Karthickeyan Chella Krishnan
- Department of Medicine, Division of Cardiology, University of California, Los Angeles, Los Angeles, CA, USA; Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, OH, USA
| | - Laurent Vergnes
- Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Nathan C Winn
- Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USA; Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Jaume Padilla
- Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USA; Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Marc Liesa
- Department of Medicine, Endocrinology, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA, 90095, USA; Molecular Cellular Integrative Physiology, University of California, Los Angeles, CA, 90095, USA.
| | - Harold S Sacks
- Department of Medicine, Endocrinology, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Endocrine and Diabetes Division, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA.
| | - Orian S Shirihai
- Department of Medicine, Endocrinology, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA; Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA, 90095, USA; Nutrition and Metabolism, Graduate Medical Sciences, Boston University School of Medicine, Boston, MA, 02118, USA; Molecular Cellular Integrative Physiology, University of California, Los Angeles, CA, 90095, USA.
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Tanigawa K, Luo Y, Kawashima A, Kiriya M, Nakamura Y, Karasawa K, Suzuki K. Essential Roles of PPARs in Lipid Metabolism during Mycobacterial Infection. Int J Mol Sci 2021; 22:ijms22147597. [PMID: 34299217 PMCID: PMC8304230 DOI: 10.3390/ijms22147597] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/13/2021] [Accepted: 07/13/2021] [Indexed: 12/25/2022] Open
Abstract
The mycobacterial cell wall is composed of large amounts of lipids with varying moieties. Some mycobacteria species hijack host cells and promote lipid droplet accumulation to build the cellular environment essential for their intracellular survival. Thus, lipids are thought to be important for mycobacteria survival as well as for the invasion, parasitization, and proliferation within host cells. However, their physiological roles have not been fully elucidated. Recent studies have revealed that mycobacteria modulate the peroxisome proliferator-activated receptor (PPAR) signaling and utilize host-derived triacylglycerol (TAG) and cholesterol as both nutrient sources and evasion from the host immune system. In this review, we discuss recent findings that describe the activation of PPARs by mycobacterial infections and their role in determining the fate of bacilli by inducing lipid metabolism, anti-inflammatory function, and autophagy.
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Affiliation(s)
- Kazunari Tanigawa
- Department of Molecular Pharmaceutics, Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan; (K.T.); (Y.N.); (K.K.)
| | - Yuqian Luo
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan; (Y.L.); (A.K.); (M.K.)
- Department of Laboratory Medicine, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China
| | - Akira Kawashima
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan; (Y.L.); (A.K.); (M.K.)
| | - Mitsuo Kiriya
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan; (Y.L.); (A.K.); (M.K.)
| | - Yasuhiro Nakamura
- Department of Molecular Pharmaceutics, Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan; (K.T.); (Y.N.); (K.K.)
| | - Ken Karasawa
- Department of Molecular Pharmaceutics, Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan; (K.T.); (Y.N.); (K.K.)
| | - Koichi Suzuki
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Itabashi-ku, Tokyo 173-8605, Japan; (Y.L.); (A.K.); (M.K.)
- Correspondence: ; Tel.: +81-3-3964-1211
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Tanigawa K, Hayashi Y, Hama K, Yamashita A, Yokoyama K, Luo Y, Kawashima A, Maeda Y, Nakamura Y, Harada A, Kiriya M, Karasawa K, Suzuki K. Mycobacterium leprae promotes triacylglycerol de novo synthesis through induction of GPAT3 expression in human premonocytic THP-1 cells. PLoS One 2021; 16:e0249184. [PMID: 33770127 PMCID: PMC7997041 DOI: 10.1371/journal.pone.0249184] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 03/12/2021] [Indexed: 12/14/2022] Open
Abstract
Mycobacterium leprae (M. leprae) is the etiological agent of leprosy, and the skin lesions of lepromatous leprosy are filled with numerous foamy or xanthomatous histiocytes that are parasitized by M. leprae. Lipids are an important nutrient for the intracellular survival of M. leprae. In this study, we attempted to determine the intracellular lipid composition and underlying mechanisms for changes in host cell lipid metabolism induced by M. leprae infection. Using high-performance thin-layer chromatography (HPTLC), we demonstrated specific induction of triacylglycerol (TAG) production in human macrophage THP-1 cells following M. leprae infection. We then used [14C] stearic acid tracing to show incorporation of this newly synthesized host cell TAG into M. leprae. In parallel with TAG accumulation, expression of host glycerol-3-phosphate acyltransferase 3 (GPAT3), a key enzyme in de novo TAG synthesis, was significantly increased in M. leprae-infected cells. CRISPR/Cas9 genome editing of GPAT3 in THP-1 cells (GPAT3 KO) dramatically reduced accumulation of TAG following M. leprae infection, intracellular mycobacterial load, and bacteria viability. These results together suggest that M. leprae induces host GPAT3 expression to facilitate TAG accumulation within macrophages to maintain a suitable environment that is crucial for intracellular survival of these bacilli.
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Affiliation(s)
- Kazunari Tanigawa
- Department of Molecular Pharmaceutics, Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo, Japan
| | - Yasuhiro Hayashi
- Department of Biological Chemistry, Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo, Japan
| | - Kotaro Hama
- Department of Physical Pharmaceutics, Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo, Japan
| | - Atsushi Yamashita
- Department of Biological Chemistry, Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo, Japan
| | - Kazuaki Yokoyama
- Department of Physical Pharmaceutics, Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo, Japan
| | - Yuqian Luo
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Itabashi-ku, Tokyo, Japan
| | - Akira Kawashima
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Itabashi-ku, Tokyo, Japan
| | - Yumi Maeda
- Department of Mycobacteriology, Leprosy Research Center, National Institute of Infectious Diseases, Higashimurayama-shi, Tokyo, Japan
| | - Yasuhiro Nakamura
- Department of Molecular Pharmaceutics, Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo, Japan
| | - Ayako Harada
- Department of Molecular Pharmaceutics, Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo, Japan
| | - Mitsuo Kiriya
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Itabashi-ku, Tokyo, Japan
| | - Ken Karasawa
- Department of Molecular Pharmaceutics, Faculty of Pharma-Science, Teikyo University, Itabashi-ku, Tokyo, Japan
| | - Koichi Suzuki
- Department of Clinical Laboratory Science, Faculty of Medical Technology, Teikyo University, Itabashi-ku, Tokyo, Japan
- Department of Mycobacteriology, Leprosy Research Center, National Institute of Infectious Diseases, Higashimurayama-shi, Tokyo, Japan
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20
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Jia XW, Fang DL, Shi XY, Lu T, Yang C, Gao Y. Inducible beige adipocytes improve impaired glucose metabolism in interscapular BAT-removal mice. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1866:158871. [PMID: 33346159 DOI: 10.1016/j.bbalip.2020.158871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 11/08/2020] [Accepted: 12/14/2020] [Indexed: 11/20/2022]
Abstract
Inducible beige adipocytes are emerging as an interesting issue in obesity and metabolism research. There is a neglected possibility that brown adipocytes are equally activated when external stimuli induce the formation of beige adipocytes. Thus, the question is whether beige adipocytes have the same functions as brown adipocytes when brown adipose tissue (BAT) is lacking. This question has not been well studied. Therefore we determine the beneficial effects of beige adipocytes upon cold challenge or CL316243 treatments in animal models of interscapular BAT (iBAT) ablation by surgical denervation. We found that denervated iBAT were activated by cold exposure and CL316243 treatments. The data show that beige adipocytes partly contribute to the improvement of impaired glucose metabolism resulting from denervated iBAT. Thus, we further used iBAT-removal animal models to abolish iBAT functions completely. We found that beige adipocytes upon cold exposure or CL316243 treatments improved impaired glucose metabolism and enhanced glucose uptake in iBAT-removal mice. The insulin signaling was activated in iBAT-removal mice upon cold exposure. Both the activation of insulin signaling and up-regulation of glucose transporter expression were observed in iBAT-removal mice with CL316243 treatments. The data show that inducible beige adipocytes may have different mechanisms to improve impaired glucose metabolism. Inducible beige adipocytes can also enhance energy expenditure and lipolytic activity of white adipose tissues when iBAT is lacking. We provide direct evidences for the beneficial effect of inducible beige adipocytes in glucose metabolism and energy expenditure in the absence of iBAT in vivo.
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Affiliation(s)
- Xiao-Wei Jia
- Beijing Key Laboratory of Cancer Invasion and Metastasis Research, Department of Human Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Dong-Liang Fang
- Beijing Key Laboratory of Cancer Invasion and Metastasis Research, Department of Human Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Xin-Yi Shi
- Beijing Key Laboratory of Cancer Invasion and Metastasis Research, Department of Human Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Tao Lu
- Beijing Key Laboratory of Cancer Invasion and Metastasis Research, Department of Human Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Chun Yang
- Beijing Key Laboratory of Cancer Invasion and Metastasis Research, Department of Human Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China; Department of Experimental Center for Basic Medical Teaching, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China.
| | - Yan Gao
- Beijing Key Laboratory of Cancer Invasion and Metastasis Research, Department of Human Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China.
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Morén B, Fryklund C, Stenkula K. Surface-associated lipid droplets: an intermediate site for lipid transport in human adipocytes? Adipocyte 2020; 9:636-648. [PMID: 33108251 PMCID: PMC7595579 DOI: 10.1080/21623945.2020.1838684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Adipose tissue plays a major role in regulating whole-body energy metabolism. While the biochemical processes regulating storage and release of excess energy are well known, the temporal organization of these events is much less defined. In this study, we have characterized the presence of small surface-associated lipid droplets, distinct from the central droplet, in primary human adipocytes. Based on microscopy analyses, we illustrate the distribution of mitochondria, endoplasmic reticulum and lysosomes in the vicinity of these specialized lipid droplets. Ultrastructure analysis confirmed the presence of small droplets in intact adipose tissue. Further, CIDEC, known to bind and regulate lipid droplet expansion, clearly localized at these lipid droplets. Neither acute or prolonged stimulation with insulin or isoprenaline, or pharmacologic intervention to suppress lipid flux, affected the presence of these lipid droplets. Still, phosphorylated perilipin and hormone-sensitive lipase accumulated at these droplets following adrenergic stimuli, which supports metabolic activity at these locations. Altogether, we propose these lipid droplet clusters represent an intermediate site involved in lipid transport in primary adipocytes.
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Affiliation(s)
- Björn Morén
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Claes Fryklund
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Karin Stenkula
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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22
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Wang X, Lu Y, Zhu L, Zhang H, Feng L. Inhibition of miR-27b Regulates Lipid Metabolism in Skeletal Muscle of Obese Rats During Hypoxic Exercise by Increasing PPARγ Expression. Front Physiol 2020; 11:1090. [PMID: 32982800 PMCID: PMC7489097 DOI: 10.3389/fphys.2020.01090] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 08/07/2020] [Indexed: 12/12/2022] Open
Abstract
Hypoxic exercise may represent a novel therapeutic strategy to reduce and prevent obesity through the regulation of lipid metabolism. During hypoxic exercise, the targeting of peroxisome proliferator-activated receptor gamma (PPARγ) by miR-27b has been proposed to be one of the mechanisms involved in the modulation of lipid metabolism. We have previously shown that miR-27b can repress PPARγ and lipid metabolism-associated factors, thereby affecting lipid metabolism during hypoxic exercise in a rat model of obesity. In the current study, we aimed to confirm the role of miR-27b in the regulation of lipid metabolism. First, miR-27b expression was either upregulated or downregulated through the injection of adeno-associated virus (AAV) 9 containing a miR-27b expression cassette or miR-27b-3p inhibitor, respectively, into the right gastrocnemius muscle of obese rats. The rats were then subjected to a 4-week program of hypoxic exercise, and a series of parameters related to lipid metabolism were systematically evaluated, including body composition, blood lipid levels, miR-27b RNA levels, and mRNA and protein levels of PPARγ and those of its downstream lipid metabolism-associated factors. No significant differences were found in body composition between rats expressing different levels of miR-27b. However, regarding blood lipids, miR-27b overexpression led to increased concentrations of triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and free fatty acids (FFAs), while inhibition of miR-27b decreased the total cholesterol (TC) level and increased that of high-density lipoprotein cholesterol (HDL-C). At the mRNA level, miR-27b overexpression downregulated the expression of Pparγ, but upregulated that of lipid metabolism-associated factors such as heart-type fatty acid-binding protein (H-FABP), fatty acid transport protein 1 (FATP1), adipose triglyceride lipase (ATGL), and lipoprotein lipase (LPL), whereas miR-27b inhibition elicited the opposite effect; however, inhibition of miR-27b led to elevated cholesterol 7 alpha-hydroxylase (CYP7A1) and fatty acid translocase 36 (CD36) levels. Similarly, at the protein level, miR-27b overexpression promoted a decrease in the concentration of PPARγ, whereas miR-27b inhibition led to an increase in PPARγ levels, as well as those of CYP7A1, CD36, ATGL, and LPL. Overall, our results indicated that hypoxic exercise regulates lipid metabolism via the miR-27b/PPARγ pathway and modulates ATGL and LPL expression through inducing their post-transcriptional modifications.
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Affiliation(s)
- Xuebing Wang
- School of Kinesiology, Shanghai University of Sport, Shanghai, China.,College of Physical Education, Guangxi University, Nanning, China
| | - Yingli Lu
- Exercise Biology Research Center, China Institute of Sport Science, Beijing, China
| | - Lei Zhu
- School of Sports Science, Qufu Normal University, Qufu, China
| | - Haibo Zhang
- Exercise Biology Research Center, China Institute of Sport Science, Beijing, China
| | - Lianshi Feng
- Exercise Biology Research Center, China Institute of Sport Science, Beijing, China
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Overby H, Yang Y, Xu X, Wang S, Zhao L. Indomethacin promotes browning and brown adipogenesis in both murine and human fat cells. Pharmacol Res Perspect 2020; 8:e00592. [PMID: 32430973 PMCID: PMC7237299 DOI: 10.1002/prp2.592] [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: 11/13/2019] [Revised: 03/21/2020] [Accepted: 03/23/2020] [Indexed: 01/17/2023] Open
Abstract
Indomethacin (Indo), a nonsteroidal antiinflammatory drug, has been shown to promote murine brown adipogenesis both in vitro and in vivo, possibly due to its peroxisome proliferator-activated receptor gamma (PPARγ)-agonist activities. However, it is unclear whether Indo induces browning of white adipocytes from both murine and human origins or induces human brown adipogenesis. To bridge the gap, this study investigated the effects of increasing concentrations of Indo on murine 3T3-L1, human primary subcutaneous white adipocytes (HPsubQ), and human brown (HBr) adipocytes. The results show that Indo dose-dependently enhanced 3T3-L1 adipocyte differentiation and upregulated both mRNA and protein expression of brown and beige adipocyte markers, while simultaneously suppressing white adipocyte-specific marker mRNA expression. mRNA and protein expression of mitochondrial biogenesis and structural genes were dose-dependently enhanced in Indo treated 3T3-L1 adipocytes. This was accompanied by augmented mitochondrial DNA, enhanced oxygen consumption, proton leak, and maximal and spare respiratory capacity. Dose-dependent transactivation of PPARγ confirmed Indo's PPARγ-agonist activity in 3T3-L1 cells. Knockdown of PPARγ significantly attenuated Indo's activities in selective browning genes, demonstrating PPARγ dependence of these effects. Moreover, Indo enhanced mRNA and protein expression of brown markers in HPsubQ adipocytes. Interestingly, Indo-induced differential effects on individual PPARγ isoforms with significant dose-dependent induction of PPARγ-2 and suppression of PPARγ-1 protein expression. Finally, Indo significantly promoted brown adipogenesis in HBr cells. Taken together, these results demonstrate Indo to be a potent thermogenic compound in both murine and human fat cells and may be explored as a therapeutic agent for obesity treatment and prevention.
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Affiliation(s)
- Haley Overby
- Department of NutritionThe University of TennesseeKnoxvilleTNUSA
| | - Yang Yang
- Department of NutritionThe University of TennesseeKnoxvilleTNUSA
| | - Xinyun Xu
- Department of NutritionThe University of TennesseeKnoxvilleTNUSA
| | - Shu Wang
- Department of Nutritional SciencesTexas Tech UniversityLubbockTXUSA
| | - Ling Zhao
- Department of NutritionThe University of TennesseeKnoxvilleTNUSA
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The biology of lipid droplet-bound mitochondria. Semin Cell Dev Biol 2020; 108:55-64. [PMID: 32446655 DOI: 10.1016/j.semcdb.2020.04.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 04/17/2020] [Accepted: 04/18/2020] [Indexed: 12/12/2022]
Abstract
Proper regulation of cellular lipid storage and oxidation is indispensable for the maintenance of cellular energy homeostasis and health. Mitochondrial function has been shown to be a main determinant of functional lipid storage and oxidation, which is of particular interest for the adipose tissue, as it is the main site of triacylglyceride storage in lipid droplets (LDs). Recent studies have identified a subpopulation of mitochondria attached to LDs, peridroplet mitochondria (PDM) that can be separated from cytoplasmic mitochondria (CM) by centrifugation. PDM have distinct bioenergetics, proteome, cristae organization and dynamics that support LD build-up, however their role in adipose tissue biology remains largely unexplored. Therefore, understanding the molecular basis of LD homeostasis and their relationship to mitochondrial function and attachment in adipocytes is of major importance.
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