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Challa AA, Vidal P, Maurya SK, Maurya CK, Baer LA, Wang Y, James NM, Pardeshi PJ, Fasano M, Carley AN, Stanford KI, Lewandowski ED. UCP1-dependent brown adipose activation accelerates cardiac metabolic remodeling and reduces initial hypertrophic and fibrotic responses to pathological stress. FASEB J 2024; 38:e23709. [PMID: 38809700 PMCID: PMC11163965 DOI: 10.1096/fj.202400922r] [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: 04/22/2024] [Revised: 05/06/2024] [Accepted: 05/16/2024] [Indexed: 05/31/2024]
Abstract
Brown adipose tissue (BAT) is correlated to cardiovascular health in rodents and humans, but the physiological role of BAT in the initial cardiac remodeling at the onset of stress is unknown. Activation of BAT via 48 h cold (16°C) in mice following transverse aortic constriction (TAC) reduced cardiac gene expression for LCFA uptake and oxidation in male mice and accelerated the onset of cardiac metabolic remodeling, with an early isoform shift of carnitine palmitoyltransferase 1 (CPT1) toward increased CPT1a, reduced entry of long chain fatty acid (LCFA) into oxidative metabolism (0.59 ± 0.02 vs. 0.72 ± 0.02 in RT TAC hearts, p < .05) and increased carbohydrate oxidation with altered glucose transporter content. BAT activation with TAC reduced early hypertrophic expression of β-MHC by 61% versus RT-TAC and reduced pro-fibrotic TGF-β1 and COL3α1 expression. While cardiac natriuretic peptide expression was yet to increase at only 3 days TAC, Nppa and Nppb expression were elevated in Cold TAC versus RT TAC hearts 2.7- and 2.4-fold, respectively. Eliminating BAT thermogenic activation with UCP1 KO mice eliminated differences between Cold TAC and RT TAC hearts, confirming effects of BAT activation rather than autonomous cardiac responses to cold. Female responses to BAT activation were blunted, with limited UCP1 changes with cold, partly due to already activated BAT in females at RT compared to thermoneutrality. These data reveal a previously unknown physiological mechanism of UCP1-dependent BAT activation in attenuating early cardiac hypertrophic and profibrotic signaling and accelerating remodeled metabolic activity in the heart at the onset of cardiac stress.
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Affiliation(s)
- Azariyas A. Challa
- Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
| | - Pablo Vidal
- Davis Heart and Lung Research Institute and Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University. Columbus, OH., 43210, USA
- Department of Surgery, General and Gastrointestinal Surgery, College of Medicine, The Ohio State University. Columbus, OH., 43210, USA
| | - Santosh K. Maurya
- Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
- Davis Heart and Lung Research Institute and Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
| | - Chandan K. Maurya
- Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
- Davis Heart and Lung Research Institute and Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
| | - Lisa A. Baer
- Davis Heart and Lung Research Institute and Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University. Columbus, OH., 43210, USA
- Department of Surgery, General and Gastrointestinal Surgery, College of Medicine, The Ohio State University. Columbus, OH., 43210, USA
| | - Yang Wang
- Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
- Davis Heart and Lung Research Institute and Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
| | - Natasha Maria James
- Davis Heart and Lung Research Institute and Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University. Columbus, OH., 43210, USA
- Department of Surgery, General and Gastrointestinal Surgery, College of Medicine, The Ohio State University. Columbus, OH., 43210, USA
| | - Parth J. Pardeshi
- Davis Heart and Lung Research Institute and Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University. Columbus, OH., 43210, USA
- Department of Surgery, General and Gastrointestinal Surgery, College of Medicine, The Ohio State University. Columbus, OH., 43210, USA
| | - Matthew Fasano
- Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
- Davis Heart and Lung Research Institute and Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
| | - Andrew N. Carley
- Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
- Davis Heart and Lung Research Institute and Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
| | - Kristin I. Stanford
- Davis Heart and Lung Research Institute and Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University. Columbus, OH., 43210, USA
- Department of Surgery, General and Gastrointestinal Surgery, College of Medicine, The Ohio State University. Columbus, OH., 43210, USA
| | - E. Douglas Lewandowski
- Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
- Davis Heart and Lung Research Institute and Department of Internal Medicine, College of Medicine, Ohio State University. Columbus, OH, 43210, USA
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Favero G, Golic I, Arnaboldi F, Cappella A, Korac A, Monsalve M, Stacchiotti A, Rezzani R. Cardiometabolic Changes in Sirtuin1-Heterozygous Mice on High-Fat Diet and Melatonin Supplementation. Int J Mol Sci 2024; 25:860. [PMID: 38255934 PMCID: PMC10815439 DOI: 10.3390/ijms25020860] [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: 12/06/2023] [Revised: 01/04/2024] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
A hypercaloric fatty diet predisposes an individual to metabolic syndrome and cardiovascular complications. Sirtuin1 (SIRT1) belongs to the class III histone deacetylase family and sustains anabolism, mitochondrial biogenesis, and fat distribution. Epididymal white adipose tissue (eWAT) is involved in inflammation, whilst interscapular brown adipose tissue (iBAT) drives metabolism in obese rodents. Melatonin, a pineal indoleamine, acting as a SIRT1 modulator, may alleviate cardiometabolic damage. In the present study, we morphologically characterized the heart, eWAT, and iBAT in male heterozygous SIRT1+/- mice (HET mice) on a high-fat diet (60%E lard) versus a standard rodent diet (8.5% E fat) and drinking melatonin (10 mg/kg) for 16 weeks. Wild-type (WT) male C57Bl6/J mice were similarly fed for comparison. Cardiomyocyte fibrosis and endoplasmic reticulum (ER) stress response worsened in HET mice on a high-fat diet vs. other groups. Lipid peroxidation, ER, and mitochondrial stress were assessed by 4 hydroxy-2-nonenal (4HNE), glucose-regulated protein78 (GRP78), CCAA/enhancer-binding protein homologous protein (CHOP), heat shock protein 60 (HSP60), and mitofusin2 immunostainings. Ultrastructural analysis indicated the prevalence of atypical inter-myofibrillar mitochondria with short, misaligned cristae in HET mice on a lard diet despite melatonin supplementation. Abnormal eWAT adipocytes, crown-like inflammatory structures, tumor necrosis factor alpha (TNFα), and iBAT whitening characterized HET mice on a hypercaloric fatty diet and were maintained after melatonin supply. All these data suggest that melatonin's mechanism of action is strictly linked to full SIRT1 expression, which is required for the exhibition of effective antioxidant and anti-inflammatory properties.
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Affiliation(s)
- Gaia Favero
- Anatomy and Physiopathology Division, Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11, 25123 Brescia, Italy; (G.F.); (R.R.)
- Interdipartimental University Center of Research “Adaption and Regeneration of Tissues and Organs (ARTO)”, University of Brescia, 25123 Brescia, Italy
| | - Igor Golic
- Center for Electron Microscopy, Faculty of Biology, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia; (I.G.); (A.K.)
| | - Francesca Arnaboldi
- Department of Biomedical Sciences for Health, University of Milan, Via Mangiagalli 31, 20133 Milan, Italy; (F.A.); (A.C.)
| | - Annalisa Cappella
- Department of Biomedical Sciences for Health, University of Milan, Via Mangiagalli 31, 20133 Milan, Italy; (F.A.); (A.C.)
- U.O. Laboratorio di Morfologia Umana Applicata, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy
| | - Aleksandra Korac
- Center for Electron Microscopy, Faculty of Biology, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia; (I.G.); (A.K.)
| | - Maria Monsalve
- Instituto de Investigaciones Biomedicas “Alberto Sols” (CSIC-UAM), 28029 Madrid, Spain;
| | - Alessandra Stacchiotti
- Department of Biomedical Sciences for Health, University of Milan, Via Mangiagalli 31, 20133 Milan, Italy; (F.A.); (A.C.)
- U.O. Laboratorio di Morfologia Umana Applicata, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy
| | - Rita Rezzani
- Anatomy and Physiopathology Division, Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11, 25123 Brescia, Italy; (G.F.); (R.R.)
- Interdipartimental University Center of Research “Adaption and Regeneration of Tissues and Organs (ARTO)”, University of Brescia, 25123 Brescia, Italy
- Italian Society for the Study of Orofacial Pain (Società Italiana Studio Dolore Orofacciale—SISDO), 25123 Brescia, Italy
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Cypess AM. Does activating brown fat contribute to important metabolic benefits in humans? Yes! J Clin Invest 2023; 133:e175282. [PMID: 38038135 PMCID: PMC10688976 DOI: 10.1172/jci175282] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023] Open
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Alvarez-Artime A, Garcia-Soler B, Gonzalez-Menendez P, Fernandez-Vega S, Cernuda-Cernuda R, Hevia D, Mayo JC, Sainz RM. Castration promotes the browning of the prostate tumor microenvironment. Cell Commun Signal 2023; 21:267. [PMID: 37770940 PMCID: PMC10536697 DOI: 10.1186/s12964-023-01294-y] [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: 06/27/2023] [Accepted: 08/23/2023] [Indexed: 09/30/2023] Open
Abstract
BACKGROUND Adipose tissue has gained attention due to its potential paracrine role. Periprostatic adipose tissue surrounds the prostate and the prostatic urethra, and it is an essential player in prostate cancer progression. Since obesity is directly related to human tumor progression, and adipose tissue depots are one of the significant components of the tumor microenvironment, the molecular mediators of the communication between adipocytes and epithelial cells are in the spotlight. Although periprostatic white adipose tissue contributes to prostate cancer progression, brown adipose tissue (BAT), which has beneficial effects in metabolic pathologies, has been scarcely investigated concerning cancer progression. Given that adipose tissue is a target of androgen signaling, the actual role of androgen removal on the periprostatic adipose tissue was the aim of this work. METHODS Surgical castration of the transgenic adenocarcinoma of the mouse prostate (TRAMP) was employed. By histology examination and software analysis, WAT and BAT tissue was quantified. 3T3-like adipocytes were used to study the role of Casodex® in modifying adipocyte differentiation and to investigate the function of the secretome of adipocytes on the proliferation of androgen-dependent and independent prostate cancer cells. Finally, the role of cell communication was assayed by TRAMP-C1 xenograft implanted in the presence of 3T3-like adipocytes. RESULTS Androgen removal increases brown/beige adipose tissue in the fat immediately surrounding the prostate glands of TRAMP mice, concomitant with an adjustment of the metabolism. Castration increases body temperature, respiratory exchange rate, and energy expenditure. Also, in vitro, it is described that blocking androgen signaling by Casodex® increases the uncoupling protein 1 (UCP1) marker in 3T3-like adipocytes. Finally, the effect of brown/beige adipocyte secretome was studied on the proliferation of prostate cancer cells in vivo and in vitro. The secretome of brown/beige adipocytes reduces the proliferation of prostate cancer cells mediated partly by the secretion of extracellular vesicles. CONCLUSIONS Consequently, we concluded that hampering androgen signaling plays a crucial role in the browning of the periprostatic adipose tissue. Also, the presence of brown adipocytes exhibits the opposite effect to that of white adipocytes in vitro regulating processes that govern the mechanisms of cell proliferation of prostate cancer cells. And finally, promoting the browning of adipose tissue in the periprostatic adipose tissue might be a way to handle prostate cancer cell progression. Video Abstract.
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Affiliation(s)
- Alejandro Alvarez-Artime
- Departamento de Morfologia y Biologia Celular, Facultad de Medicina, University of Oviedo, Julian Claveria 6, 33006, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), 33006, Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Avda. Hospital Universitario, 33011, Oviedo, Spain
| | - Belen Garcia-Soler
- Departamento de Morfologia y Biologia Celular, Facultad de Medicina, University of Oviedo, Julian Claveria 6, 33006, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), 33006, Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Avda. Hospital Universitario, 33011, Oviedo, Spain
| | - Pedro Gonzalez-Menendez
- Departamento de Morfologia y Biologia Celular, Facultad de Medicina, University of Oviedo, Julian Claveria 6, 33006, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), 33006, Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Avda. Hospital Universitario, 33011, Oviedo, Spain
| | - Sheila Fernandez-Vega
- Departamento de Morfologia y Biologia Celular, Facultad de Medicina, University of Oviedo, Julian Claveria 6, 33006, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), 33006, Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Avda. Hospital Universitario, 33011, Oviedo, Spain
| | - Rafael Cernuda-Cernuda
- Departamento de Morfologia y Biologia Celular, Facultad de Medicina, University of Oviedo, Julian Claveria 6, 33006, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), 33006, Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Avda. Hospital Universitario, 33011, Oviedo, Spain
| | - David Hevia
- Departamento de Morfologia y Biologia Celular, Facultad de Medicina, University of Oviedo, Julian Claveria 6, 33006, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), 33006, Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Avda. Hospital Universitario, 33011, Oviedo, Spain
| | - Juan C Mayo
- Departamento de Morfologia y Biologia Celular, Facultad de Medicina, University of Oviedo, Julian Claveria 6, 33006, Oviedo, Spain.
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), 33006, Oviedo, Spain.
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Avda. Hospital Universitario, 33011, Oviedo, Spain.
| | - Rosa M Sainz
- Departamento de Morfologia y Biologia Celular, Facultad de Medicina, University of Oviedo, Julian Claveria 6, 33006, Oviedo, Spain.
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), 33006, Oviedo, Spain.
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Avda. Hospital Universitario, 33011, Oviedo, Spain.
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Peres Valgas Da Silva C, Shettigar VK, Baer LA, Abay E, Pinckard KM, Vinales J, Sturgill SL, Vidal P, Ziolo MT, Stanford KI. Exercise training after myocardial infarction increases survival but does not prevent adverse left ventricle remodeling and dysfunction in high-fat diet fed mice. Life Sci 2022; 311:121181. [PMID: 36372212 PMCID: PMC9712172 DOI: 10.1016/j.lfs.2022.121181] [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: 08/22/2022] [Revised: 11/04/2022] [Accepted: 11/07/2022] [Indexed: 11/13/2022]
Abstract
AIMS Aerobic exercise is an important component of rehabilitation after cardiovascular injuries including myocardial infarction (MI). In human studies, the beneficial effects of exercise after an MI are blunted in patients who are obese or glucose intolerant. Here, we investigated the effects of exercise on MI-induced cardiac dysfunction and remodeling in mice chronically fed a high-fat diet (HFD). MAIN METHODS C57Bl/6 male mice were fed either a standard (Chow; 21% kcal/fat) or HFD (60% kcal/fat) for 36 weeks. After 24 weeks of diet, the HFD mice were randomly subjected to an MI (MI) or a sham surgery (Sham). Following the MI or sham surgery, a subset of mice were subjected to treadmill exercise. KEY FINDINGS HFD resulted in obesity and glucose intolerance, and this was not altered by exercise or MI. MI resulted in decreased ejection fraction, increased left ventricle mass, increased end systolic and diastolic diameters, increased cardiac fibrosis, and increased expression of genes involved in cardiac hypertrophy and heart failure in the MI-Sed and MI-Exe mice. Exercise prevented HFD-induced cardiac fibrosis in Sham mice (Sham-Exe) but not in MI-Exe mice. Exercise did, however, reduce post-MI mortality. SIGNIFICANCE These data indicate that exercise significantly increased survival after MI in a model of diet-induced obesity independent of effects on cardiac function. These data have important translational ramifications because they demonstrate that environmental interventions, including diet, need to be carefully evaluated and taken into consideration to support the effects of exercise in the cardiac rehabilitation of patients who are obese.
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Affiliation(s)
- Carmem Peres Valgas Da Silva
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America; Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, United States of America
| | - Vikram K Shettigar
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America; Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, United States of America
| | - Lisa A Baer
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America; Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, United States of America
| | - Eaman Abay
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America; Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, United States of America
| | - Kelsey M Pinckard
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America; Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, United States of America
| | - Jorge Vinales
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America; Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, United States of America
| | - Sarah L Sturgill
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America; Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, United States of America
| | - Pablo Vidal
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America; Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, United States of America
| | - Mark T Ziolo
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America; Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, United States of America; Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, United States of America
| | - Kristin I Stanford
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America; Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, United States of America; Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, United States of America.
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Brown fat holds promise for addressing obesity and a host of related ills. Proc Natl Acad Sci U S A 2022; 119:e2216435119. [PMID: 36227944 PMCID: PMC9618075 DOI: 10.1073/pnas.2216435119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Differential Responses to Sigma-1 or Sigma-2 Receptor Ablation in Adiposity, Fat Oxidation, and Sexual Dimorphism. Int J Mol Sci 2022; 23:ijms231810846. [PMID: 36142759 PMCID: PMC9506228 DOI: 10.3390/ijms231810846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 09/09/2022] [Accepted: 09/13/2022] [Indexed: 11/20/2022] Open
Abstract
Obesity is increasing at epidemic rates across the US and worldwide, as are its co-morbidities, including type-2 diabetes and cardiovascular disease. Thus, targeted interventions to reduce the prevalence of obesity are of the utmost importance. The sigma-1 receptor (S1R) and sigma-2 receptor (S2R; encoded by Tmem97) belong to the same class of drug-binding sites, yet they are genetically distinct. There are multiple ongoing clinical trials focused on sigma receptors, targeting diseases ranging from Alzheimer’s disease through chronic pain to COVID-19. However, little is known regarding their gene-specific role in obesity. In this study, we measured body composition, used a comprehensive laboratory-animal monitoring system, and determined the glucose and insulin tolerance in mice fed a high-fat diet. Compared to Sigmar1+/+ mice of the same sex, the male and female Sigmar1−/− mice had lower fat mass (17% and 12% lower, respectively), and elevated lean mass (16% and 10% higher, respectively), but S1R ablation had no effect on their metabolism. The male Tmem97−/− mice exhibited 7% lower fat mass, 8% higher lean mass, increased volumes of O2 and CO2, a decreased respiratory exchange ratio indicating elevated fatty-acid oxidation, and improved insulin tolerance, compared to the male Tmem97+/+ mice. There were no changes in any of these parameters in the female Tmem97−/− mice. Together, these data indicate that the S1R ablation in male and female mice or the S2R ablation in male mice protects against diet-induced adiposity, and that S2R ablation, but not S1R deletion, improves insulin tolerance and enhances fatty-acid oxidation in male mice. Further mechanistic investigations may lead to translational strategies to target differential S1R/S2R regulations and sexual dimorphism for precision treatments of obesity.
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