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Fu Y, Batushansky A, Kinter M, Huebner JL, Kraus VB, Griffin TM. Effects of Leptin and Body Weight on Inflammation and Knee Osteoarthritis Phenotypes in Female Rats. JBMR Plus 2023; 7:e10754. [PMID: 37457883 PMCID: PMC10339097 DOI: 10.1002/jbm4.10754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/22/2023] [Accepted: 04/13/2023] [Indexed: 07/18/2023] Open
Abstract
Leptin is a proinflammatory adipokine that contributes to obesity-associated osteoarthritis (OA), especially in women. However, the extent to which leptin causes knee OA separate from the effect of increased body weight is not clear. We hypothesized that leptin is necessary to induce knee OA in obese female rats but not sufficient to induce knee OA in lean rats lacking systemic metabolic inflammation. The effect of obesity without leptin signaling was modeled by comparing female lean Zucker rats to pair fed obese Zucker rats, which possess mutant fa alleles of the leptin receptor gene. The effect of leptin without obesity was modeled in female F344BN F1 hybrid rats by systemically administering recombinant rat leptin versus saline for 23 weeks via osmotic pumps. Primary OA outcomes included cartilage histopathology and subchondral bone micro-computed tomography. Secondary outcomes included targeted cartilage proteomics, serum inflammation, and synovial fluid inflammation following an acute intra-articular challenge with interleukin-1β (IL-1β). Compared to lean Zucker rats, obese Zucker rats developed more severe tibial osteophytes and focal cartilage lesions in the medial tibial plateau, with modest changes in proximal tibial epiphysis trabecular bone structure. In contrast, exogenous leptin treatment, which increased plasma leptin sixfold without altering body weight, caused mild generalized cartilage fibrillation and reduced Safranin O staining compared to vehicle-treated animals. Leptin also significantly increased subchondral and trabecular bone volume and bone mineral density in the proximal tibia. Cartilage metabolic and antioxidant enzyme protein levels were substantially elevated with leptin deficiency and minimally suppressed with leptin treatment. In contrast, leptin treatment induced greater changes in systemic and local inflammatory mediators compared to leptin receptor deficiency, including reduced serum IL-6 and increased synovial fluid IL-1β. In conclusion, rat models that separately elevate leptin or body weight develop distinct OA-associated phenotypes, revealing how obesity increases OA pathology through both leptin-dependent and independent pathways. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Yao Fu
- Aging and Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOklahomaUSA
| | - Albert Batushansky
- Aging and Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOklahomaUSA
| | - Michael Kinter
- Aging and Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOklahomaUSA
- Oklahoma Center for GeroscienceUniversity of Oklahoma Health Sciences CenterOklahoma CityOklahomaUSA
| | - Janet L. Huebner
- Duke Molecular Physiology InstituteDuke University, School of Medicine, Duke UniversityDurhamNorth CarolinaUSA
| | - Virginia B. Kraus
- Duke Molecular Physiology InstituteDuke University, School of Medicine, Duke UniversityDurhamNorth CarolinaUSA
- Division of Rheumatology, Department of MedicineDuke University, School of Medicine, Duke UniversityDurhamNorth CarolinaUSA
| | - Timothy M. Griffin
- Aging and Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOklahomaUSA
- Oklahoma Center for GeroscienceUniversity of Oklahoma Health Sciences CenterOklahoma CityOklahomaUSA
- Department of Biochemistry and Molecular BiologyUniversity of Oklahoma Health Sciences CenterOklahoma CityOklahomaUSA
- Veterans Affairs Medical CenterOklahoma CityOklahomaUSA
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Stranahan AM, Guo DH, Yamamoto M, Hernandez CM, Khodadadi H, Baban B, Zhi W, Lei Y, Lu X, Ding K, Isales CM. Sex Differences in Adipose Tissue Distribution Determine Susceptibility to Neuroinflammation in Mice With Dietary Obesity. Diabetes 2023; 72:245-260. [PMID: 36367881 PMCID: PMC9871229 DOI: 10.2337/db22-0192] [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: 03/02/2022] [Accepted: 11/08/2022] [Indexed: 11/13/2022]
Abstract
Preferential energy storage in subcutaneous adipose tissue (SAT) confers protection against obesity-induced pathophysiology in females. Females also exhibit distinct immunological responses, relative to males. These differences are often attributed to sex hormones, but reciprocal interactions between metabolism, immunity, and gonadal steroids remain poorly understood. We systematically characterized adipose tissue hypertrophy, sex steroids, and inflammation in male and female mice after increasing durations of high-fat diet (HFD)-induced obesity. After observing that sex differences in adipose tissue distribution before HFD were correlated with lasting protection against inflammation in females, we hypothesized that a priori differences in the ratio of subcutaneous to visceral fat might mediate this relationship. To test this, male and female mice underwent SAT lipectomy (LPX) or sham surgery before HFD challenge, followed by analysis of glial reactivity, adipose tissue inflammation, and reproductive steroids. Because LPX eliminated female resistance to the proinflammatory effects of HFD without changing circulating sex hormones, we conclude that sexually dimorphic organization of subcutaneous and visceral fat determines susceptibility to inflammation in obesity.
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Affiliation(s)
- Alexis M. Stranahan
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA
| | - De-Huang Guo
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA
| | - Masaki Yamamoto
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA
| | - Caterina M. Hernandez
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Hesam Khodadadi
- Department of Oral Biology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Babak Baban
- Department of Oral Biology, Medical College of Georgia, Augusta University, Augusta, GA
- Plastic Surgery Section, Department of Surgery, Medical College of Georgia, Augusta University, Augusta, GA
| | - Wenbo Zhi
- Department of Obstetrics and Gynecology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Yun Lei
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA
| | - Xinyun Lu
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA
| | - Kehong Ding
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA
| | - Carlos M. Isales
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA
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Griffin TM, Batushansky A, Hudson J, Lopes EBP. Correlation network analysis shows divergent effects of a long-term, high-fat diet and exercise on early stage osteoarthritis phenotypes in mice. JOURNAL OF SPORT AND HEALTH SCIENCE 2020; 9:119-131. [PMID: 32099720 PMCID: PMC7031811 DOI: 10.1016/j.jshs.2019.05.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/02/2019] [Accepted: 04/23/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Obesity increases knee osteoarthritis (OA) risk through metabolic, inflammatory, and biomechanical factors, but how these systemic and local mediators interact to drive OA pathology is not well understood. We tested the effect of voluntary running exercise after chronic diet-induced obesity on knee OA-related cartilage and bone pathology in mice. We then used a correlation-based network analysis to identify systemic and local factors associated with early-stage knee OA phenotypes among the different diet and exercise groups. METHODS Male C57BL/6J mice were fed a defined control (10% kcal fat) or high fat (HF) (60% kcal fat) diet from 6 to 37 weeks of age. At 25 weeks, one-half of the mice from each diet group were housed in cages with running wheels for the remainder of the study. Histology, micro computed tomography, and magnetic resonance imaging were used to evaluate changes in joint tissue structure and OA pathology. These local variables were then compared to systemic metabolic (body mass, body fat, and glucose tolerance), inflammatory (serum adipokines and inflammatory mediators), and functional (mechanical tactile sensitivity and grip strength) outcomes using a correlation-based network analysis. Diet and exercise effects were evaluated by two-way analysis of variance. RESULTS An HF diet increased the infrapatellar fat pad size and posterior joint osteophytes, and wheel running primarily altered the subchondral cortical and trabecular bone. Neither HF diet nor exercise altered average knee cartilage OA scores compared to control groups. However, the coefficient of variation was ≥25% for many outcomes, and some mice in both diet groups developed moderate OA (≥33% maximum score). This supported using correlation-based network analyses to identify systemic and local factors associated with early-stage knee OA phenotypes. In wheel-running cohorts, an HF diet reduced the network size compared to the control diet group despite similar running distances, suggesting that diet-induced obesity dampens the effects of exercise on systemic and local OA-related factors. Each of the 4 diet and activity groups showed mostly unique networks of local and systemic factors correlated with early-stage knee OA. CONCLUSION Despite minimal group-level effects of chronic diet-induced obesity and voluntary wheel running on knee OA pathology under the current test durations, diet and exercise substantially altered the relationships among systemic and local variables associated with early-stage knee OA. These results suggest that distinct pre-OA phenotypes may exist prior to the development of disease.
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MESH Headings
- Adipokines/blood
- Animals
- Cartilage, Articular/pathology
- Cartilage, Articular/physiopathology
- Diet, High-Fat/adverse effects
- Disease Models, Animal
- Hand Strength
- Hyperalgesia/physiopathology
- Inflammation Mediators/blood
- Male
- Mice, Inbred C57BL
- Obesity/complications
- Obesity/physiopathology
- Osteoarthritis, Knee/etiology
- Osteoarthritis, Knee/metabolism
- Osteoarthritis, Knee/pathology
- Osteoarthritis, Knee/physiopathology
- Physical Conditioning, Animal
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Affiliation(s)
- Timothy M Griffin
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation (OMRF), Oklahoma City, OK 73104, USA; Reynolds Oklahoma Center on Aging and Departments of Biochemistry and Molecular Biology, Physiology, and Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Albert Batushansky
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation (OMRF), Oklahoma City, OK 73104, USA
| | - Joanna Hudson
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation (OMRF), Oklahoma City, OK 73104, USA
| | - Erika Barboza Prado Lopes
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation (OMRF), Oklahoma City, OK 73104, USA
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Vargas VE, Gurung S, Grant B, Hyatt K, Singleton K, Myers SM, Saunders D, Njoku C, Towner R, Myers DA. Gestational hypoxia disrupts the neonatal leptin surge and programs hyperphagia and obesity in male offspring in the Sprague-Dawley rat. PLoS One 2017; 12:e0185272. [PMID: 28957383 PMCID: PMC5619766 DOI: 10.1371/journal.pone.0185272] [Citation(s) in RCA: 7] [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: 04/06/2017] [Accepted: 09/08/2017] [Indexed: 12/04/2022] Open
Abstract
The effect of gestational hypoxia on the neonatal leptin surge, development of hypothalamic arcuate nuclei (ARH) projections and appetite that could contribute to the programming of offspring obesity is lacking. We examined the effect of 12% O2 from gestational days 15–19 in the Sprague-Dawley rat on post-weaning appetite, fat deposition by MRI, adipose tissue cytokine expression, the neonatal leptin surge, ARH response to exogenous leptin, and αMSH projections to the paraventricular nucleus (PVN) in response to a high fat (HFD) or control diet (CD) in male offspring. Normoxia (NMX) and Hypoxia (HPX) offspring exhibited increased food intake when fed a HFD from 5–8 weeks post-birth; HPX offspring on the CD had increased food intake from weeks 5–7 vs. NMX offspring on a CD. HPX offspring on a HFD remained hyperphagic through 23 weeks. Body weight were the same between offspring from HPX vs. NMX dams from 4–12 weeks of age fed a CD or HFD. By 14–23 weeks of age, HPX offspring fed the CD or HFD as well as male NMX offspring fed the HFD were heavier vs. NMX offspring fed the CD. HPX offspring fed a CD exhibited increased abdominal adiposity (MRI) that was amplified by a HFD. HPX offspring fed a HFD exhibited the highest abdominal fat cytokine expression. HPX male offspring had higher plasma leptin from postnatal day (PN) 6 through 14 vs. NMX pups. HPX offspring exhibited increased basal c-Fos labeled cells in the ARH vs. NMX pups on PN16. Leptin increased c-Fos staining in the ARH in NMX but not HPX offspring at PN16. HPX offspring had fewer αMSH fibers in the PVN vs. NMX offspring on PN16. In conclusion, gestational hypoxia impacts the developing ARH resulting in hyperphagia contributing to adult obesity on a control diet and exacerbated by a HFD.
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Affiliation(s)
- Vladimir E. Vargas
- Departments of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Sunam Gurung
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Benjamin Grant
- Departments of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Kimberly Hyatt
- Departments of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Krista Singleton
- Departments of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Sarah M. Myers
- Departments of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Debra Saunders
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Charity Njoku
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Rheal Towner
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Dean A. Myers
- Departments of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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Meriga B, Naidu PB, Muniswamy G, Kumar GH, Naik RR, Pothani S. Ethanolic Fraction of Terminalia tomentosa Attenuates Biochemical and Physiological Derangements in Diet Induced Obese Rat Model by Regulating Key Lipid Metabolizing Enzymes and Adipokines. Pharmacogn Mag 2017; 13:385-392. [PMID: 28839361 PMCID: PMC5551354 DOI: 10.4103/0973-1296.208871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 02/17/2016] [Indexed: 12/15/2022] Open
Abstract
The prevalence of overweight-obesity and associated comorbidities have reached alarming levels necessitating the need to explore effective therapeutics. In the present work, we demonstrated the promising antiobesity activity of ethanolic fraction of Terminalia tomentosa bark (EFTT) in diet induced obese rat model. High Fat Diet (HFD)-fed obese rats were orally administered with EFTT (50, 100 and 200 mg/kg body weight). Changes in body weight, body composition, bone mineral concentration, bone mineral density, plasma glucose, insulin, leptin, adiponectin, circulatory and tissue lipid profiles, and the activities of liver antioxidant enzymes, key lipid metabolic enzymes and mRNA expressions of fatty acid synthase (FAS), peroxisome proliferator-activated receptor gamma (PPAR-γ), leptin and tumor necrosis factor alpha (TNF-α) were assessed in experimental rats in the presence and absence of EFTT. At a dose of 200 mg/kg b.wt, EFTT has substantially attenuated body weight and related patho-physiological alterations in HFD-induced obese rats. These findings were correlated with histological observations of adipose tissue. The therapeutic activity of EFTT could be possibly through restoration of antioxidants status, regulation of key lipid metabolizing enzymes, expression of FAS, leptin, PPAR-γ and by synchronized control of energy metabolism in liver and adipose tissue.
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Affiliation(s)
- Balaji Meriga
- Animal Physiology and Biochemistry Laboratory, Department of Biochemistry, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
| | - Parim Brahma Naidu
- Animal Physiology and Biochemistry Laboratory, Department of Biochemistry, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
| | - Ganjayi Muniswamy
- Animal Physiology and Biochemistry Laboratory, Department of Biochemistry, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
| | - Gen Hanuma Kumar
- Animal Physiology and Biochemistry Laboratory, Department of Biochemistry, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
| | - Ramavat Ravindar Naik
- National Center for Laboratory Animal Sciences, National Institute of Nutrition, Hyderabad, India
| | - Suresh Pothani
- National Center for Laboratory Animal Sciences, National Institute of Nutrition, Hyderabad, India
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Barboza E, Hudson J, Chang WP, Kovats S, Towner RA, Silasi-Mansat R, Lupu F, Kent C, Griffin TM. Profibrotic Infrapatellar Fat Pad Remodeling Without M1 Macrophage Polarization Precedes Knee Osteoarthritis in Mice With Diet-Induced Obesity. Arthritis Rheumatol 2017; 69:1221-1232. [PMID: 28141918 DOI: 10.1002/art.40056] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/24/2017] [Indexed: 12/22/2022]
Abstract
OBJECTIVE To test the hypothesis that high-fat (HF) diet-induced obesity increases proinflammatory cytokine expression, macrophage infiltration, and M1 polarization in the infrapatellar fat pad (IFP) prior to knee cartilage degeneration. METHODS We characterized the effect of HF feeding on knee OA pathology, body adiposity, and glucose intolerance in male C57BL/6J mice and identified a diet duration that induces metabolic dysfunction prior to cartilage degeneration. Magnetic resonance imaging and histomorphology were used to quantify changes in the epididymal, subcutaneous, and infrapatellar fat pads and in adipocyte sizes. Finally, we used targeted gene expression and protein arrays, immunohistochemistry, and flow cytometry to quantify differences in fat pad markers of inflammation and immune cell populations. RESULTS Twenty weeks of feeding with an HF diet induced marked obesity, glucose intolerance, and early osteoarthritis (OA), including osteophytes and cartilage tidemark duplication. This duration of HF feeding increased the IFP volume. However, it did not increase IFP inflammation, macrophage infiltration, or M1 macrophage polarization as observed in epididymal fat. Furthermore, leptin protein levels were reduced. This protection from obesity-induced inflammation corresponded to increased IFP fibrosis and the absence of adipocyte hypertrophy. CONCLUSION The IFP does not recapitulate classic abdominal adipose tissue inflammation during the early stages of knee OA in an HF diet-induced model of obesity. Consequently, these findings do not support the hypothesis that IFP inflammation is an initiating factor of obesity-induced knee OA. Furthermore, the profibrotic and antihypertrophic responses of IFP adipocytes to HF feeding suggest that intraarticular adipocytes are subject to distinct spatiotemporal structural and metabolic regulation among fat pads.
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Affiliation(s)
| | | | | | - Susan Kovats
- Oklahoma Medical Research Foundation, Oklahoma City
| | | | | | - Florea Lupu
- Oklahoma Medical Research Foundation, Oklahoma City
| | - Collin Kent
- Oklahoma Medical Research Foundation, Oklahoma City
| | - Timothy M Griffin
- Oklahoma Medical Research Foundation, Reynolds Oklahoma Center on Aging, and University of Oklahoma Health Sciences Center, Oklahoma City
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Hu HH, Chen J, Shen W. Segmentation and quantification of adipose tissue by magnetic resonance imaging. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2015; 29:259-76. [PMID: 26336839 DOI: 10.1007/s10334-015-0498-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 08/11/2015] [Accepted: 08/12/2015] [Indexed: 12/13/2022]
Abstract
In this brief review, introductory concepts in animal and human adipose tissue segmentation using proton magnetic resonance imaging (MRI) and computed tomography are summarized in the context of obesity research. Adipose tissue segmentation and quantification using spin relaxation-based (e.g., T1-weighted, T2-weighted), relaxometry-based (e.g., T1-, T2-, T2*-mapping), chemical-shift selective, and chemical-shift encoded water-fat MRI pulse sequences are briefly discussed. The continuing interest to classify subcutaneous and visceral adipose tissue depots into smaller sub-depot compartments is mentioned. The use of a single slice, a stack of slices across a limited anatomical region, or a whole body protocol is considered. Common image post-processing steps and emerging atlas-based automated segmentation techniques are noted. Finally, the article identifies some directions of future research, including a discussion on the growing topic of brown adipose tissue and related segmentation considerations.
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Affiliation(s)
- Houchun Harry Hu
- Department of Radiology, Phoenix Children's Hospital, 1919 East Thomas Road, Phoenix, AZ, 85016, USA.
| | - Jun Chen
- Obesity Research Center, Department of Medicine, Columbia University Medical Center, 1150 Saint Nicholas Avenue, New York, NY, 10032, USA
| | - Wei Shen
- Obesity Research Center, Department of Medicine and Institute of Human Nutrition, Columbia University Medical Center, 1150 Saint Nicholas Avenue, New York, NY, 10032, USA
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Zhao Y, Ling F, Griffin TM, He T, Towner R, Ruan H, Sun XH. Up-regulation of the Sirtuin 1 (Sirt1) and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) genes in white adipose tissue of Id1 protein-deficient mice: implications in the protection against diet and age-induced glucose intolerance. J Biol Chem 2014; 289:29112-22. [PMID: 25190816 DOI: 10.1074/jbc.m114.571679] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Id1, a helix-loop-helix (HLH) protein that inhibits the function of basic HLH E protein transcription factors in lymphoid cells, has been implicated in diet- and age-induced obesity by unknown mechanisms. Here we show that Id1-deficient mice are resistant to a high fat diet- and age-induced obesity, as revealed by reduced weight gain and body fat, increased lipid oxidation, attenuated hepatosteatosis, lower levels of lipid droplets in brown adipose tissue, and smaller white adipocytes after a high fat diet feeding or in aged animals. Id1 deficiency improves glucose tolerance, lowers serum insulin levels, and reduces TNFα gene expression in white adipose tissue. Id1 deficiency also increased expression of Sirtuin 1 and peroxisome proliferator-activated receptor γ coactivator 1α, regulators of mitochondrial biogenesis and energy expenditure, in the white adipose tissue. This effect was accompanied by the elevation of several genes encoding proteins involved in oxidative phosphorylation and fatty acid oxidation, such as cytochrome c, medium-chain acyl-CoA dehydrogenase, and adipocyte protein 2. Moreover, the phenotype for Id1 deficiency was similar to that of mice expressing an E protein dominant-positive construct, ET2, suggesting that the balance between Id and E proteins plays a role in regulating lipid metabolism and insulin sensitivity.
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Affiliation(s)
- Ying Zhao
- From the Program in Immunobiology and Cancer Research
| | - Flora Ling
- From the Program in Immunobiology and Cancer Research, Department of Cell Biology and
| | - Timothy M Griffin
- Program in Free Radical Biology and Aging, and Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, and
| | - Ting He
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Rheal Towner
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Hong Ruan
- Department of Physiology and Biophysics, Rutgers University, Piscataway, New Jersey 08854
| | - Xiao-Hong Sun
- From the Program in Immunobiology and Cancer Research, Department of Cell Biology and
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Yao L, Heuser-Baker J, Herlea-Pana O, Zhang N, Szweda LI, Griffin TM, Barlic-Dicen J. Deficiency in adipocyte chemokine receptor CXCR4 exacerbates obesity and compromises thermoregulatory responses of brown adipose tissue in a mouse model of diet-induced obesity. FASEB J 2014; 28:4534-50. [PMID: 25016030 DOI: 10.1096/fj.14-249797] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The chemokine receptor CXCR4 is expressed on adipocytes and macrophages in adipose tissue, but its role in this tissue remains unknown. We evaluated whether deficiency in either adipocyte or myeloid leukocyte CXCR4 affects body weight (BW) and adiposity in a mouse model of high-fat-diet (HFD)-induced obesity. We found that ablation of adipocyte, but not myeloid leukocyte, CXCR4 exacerbated obesity. The HFD-fed adipocyte-specific CXCR4-knockout (AdCXCR4ko) mice, compared to wild-type C57BL/6 control mice, had increased BW (average: 52.0 g vs. 35.5 g), adiposity (average: 49.3 vs. 21.0% of total BW), and inflammatory leukocyte content in white adipose tissue (WAT), despite comparable food intake. As previously reported, HFD feeding increased uncoupling protein 1 (UCP1) expression (fold increase: 3.5) in brown adipose tissue (BAT) of the C57BL/6 control mice. However, no HFD-induced increase in UCP1 expression was observed in the AdCXCR4ko mice, which were cold sensitive. Thus, our study suggests that adipocyte CXCR4 limits development of obesity by preventing excessive inflammatory cell recruitment into WAT and by supporting thermogenic activity of BAT. Since CXCR4 is conserved between mouse and human, the newfound role of CXCR4 in mouse adipose tissue may parallel the role of this chemokine receptor in human adipose tissue.
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Affiliation(s)
| | | | | | | | - Luke I Szweda
- Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Timothy M Griffin
- Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
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