1
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Zhang X, Wang Q, Wang Y, Ma C, Zhao Q, Yin H, Li L, Wang D, Huang Y, Zhao Y, Shi X, Li X, Huang C. Interleukin-6 promotes visceral adipose tissue accumulation during aging via inhibiting fat lipolysis. Int Immunopharmacol 2024; 132:111906. [PMID: 38593501 DOI: 10.1016/j.intimp.2024.111906] [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: 11/03/2023] [Revised: 03/06/2024] [Accepted: 03/18/2024] [Indexed: 04/11/2024]
Abstract
BACKGROUND Age-related visceral obesity could contribute to the development of cardiometabolic complications. The pathogenesis of visceral fat mass accumulation during the aging process remains complex and largely unknown. Interleukin-6 (IL-6) has emerged as one of the prominent inflammaging markers which are elevated in circulation during aging. However, the precise role of IL-6 in regulating age-related visceral adipose tissue accumulation remains uncertain. RESULTS A cross-sectional study including 77 older adults (≥65 years of age) was initially conducted. There was a significant positive association between serum IL-6 levels and visceral fat mass. We subsequently validated a modest but significant elevation in serum IL-6 levels in aged mice. Furthermore, we demonstrated that compared to wildtype control, IL-6 deficiency (IL-6 KO) significantly attenuated the accumulation of visceral adipose tissue during aging. Further metabolic characterization suggested that IL-6 deficiency resulted in improved lipid metabolism parameters and energy expenditure in aged mice. Moreover, histological examinations of adipose depots revealed that the absence of IL-6 ameliorated adipocyte hypertrophy in visceral adipose tissue of aged mice. Mechanically, the ablation of IL-6 could promote the PKA-mediated lipolysis and consequently mitigate lipid accumulation in adipose tissue in aged mice. CONCLUSION Our findings identify a detrimental role of IL-6 during the aging process by promoting visceral adipose tissue accumulation through inhibition of lipolysis. Therefore, strategies aimed at preventing or reducing IL-6 levels may potentially ameliorate age-related obesity and improve metabolism during aging.
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Affiliation(s)
- Xiaofang Zhang
- Department of Endocrinology and Diabetes, Xiamen Diabetes Institute, Fujian Key Laboratory of Translational Research for Diabetes, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361003, China
| | - Qingxuan Wang
- Department of Endocrinology and Diabetes, Xiamen Diabetes Institute, Fujian Key Laboratory of Translational Research for Diabetes, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361003, China
| | - Yaru Wang
- Department of Endocrinology and Diabetes, Xiamen Diabetes Institute, Fujian Key Laboratory of Translational Research for Diabetes, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361003, China
| | - Chen Ma
- Department of Endocrinology and Diabetes, Xiamen Diabetes Institute, Fujian Key Laboratory of Translational Research for Diabetes, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361003, China
| | - Qing Zhao
- Department of Endocrinology and Diabetes, Xiamen Diabetes Institute, Fujian Key Laboratory of Translational Research for Diabetes, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361003, China
| | - Hongyan Yin
- Department of Endocrinology and Diabetes, Xiamen Diabetes Institute, Fujian Key Laboratory of Translational Research for Diabetes, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361003, China
| | - Long Li
- Department of Endocrinology and Diabetes, Xiamen Diabetes Institute, Fujian Key Laboratory of Translational Research for Diabetes, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361003, China; Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China
| | - Dongmei Wang
- Department of Endocrinology and Diabetes, Xiamen Diabetes Institute, Fujian Key Laboratory of Translational Research for Diabetes, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361003, China; Department of Public Health and Medical Technology, Xiamen Medical College, Xiamen 361023, China
| | - Yinxiang Huang
- Department of Endocrinology and Diabetes, Xiamen Diabetes Institute, Fujian Key Laboratory of Translational Research for Diabetes, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361003, China
| | - Yan Zhao
- Department of Endocrinology and Diabetes, Xiamen Diabetes Institute, Fujian Key Laboratory of Translational Research for Diabetes, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361003, China
| | - Xiulin Shi
- Department of Endocrinology and Diabetes, Xiamen Diabetes Institute, Fujian Key Laboratory of Translational Research for Diabetes, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361003, China
| | - Xuejun Li
- Department of Endocrinology and Diabetes, Xiamen Diabetes Institute, Fujian Key Laboratory of Translational Research for Diabetes, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361003, China.
| | - Caoxin Huang
- Department of Endocrinology and Diabetes, Xiamen Diabetes Institute, Fujian Key Laboratory of Translational Research for Diabetes, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361003, China.
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2
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Carey A, Nguyen K, Kandikonda P, Kruglov V, Bradley C, Dahlquist KJV, Cholensky S, Swanson W, Badovinac VP, Griffith TS, Camell CD. Age-associated accumulation of B cells promotes macrophage inflammation and inhibits lipolysis in adipose tissue during sepsis. Cell Rep 2024; 43:113967. [PMID: 38492219 PMCID: PMC11014686 DOI: 10.1016/j.celrep.2024.113967] [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: 09/26/2023] [Revised: 02/14/2024] [Accepted: 02/29/2024] [Indexed: 03/18/2024] Open
Abstract
Non-canonical lipolysis induced by inflammatory cytokines or Toll-like receptor ligands is required for the regulation of inflammation during endotoxemia and sepsis. Canonical lipolysis induced by catecholamines declines during aging due to factors including an expansion of lymphocytes, pro-inflammatory macrophage polarization, and an increase in chronic low-grade inflammation; however, the extent to which the non-canonical pathway of lipolysis is active and impacted by immune cells during aging remains unclear. Therefore, we aimed to define the extent to which immune cells from old mice influence non-canonical lipolysis during sepsis. We identified age-associated impairments of non-canonical lipolysis and an accumulation of dysfunctional B1 B cells in the visceral white adipose tissue (vWAT) of old mice. Lifelong deficiency of B cells results in restored non-canonical lipolysis and reductions in pro-inflammatory macrophage populations. Our study suggests that targeting the B cell-macrophage signaling axis may resolve metabolic dysfunction in aged vWAT and attenuate septic severity in older individuals.
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Affiliation(s)
- Anna Carey
- Molecular Pharmacology and Therapeutics Graduate Program, Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA; Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Katie Nguyen
- Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Pranathi Kandikonda
- Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Victor Kruglov
- Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Claire Bradley
- Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Korbyn J V Dahlquist
- Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Stephanie Cholensky
- Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Whitney Swanson
- Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA; Department of Urology, University of Minnesota, Minneapolis, MN 55455, USA
| | | | - Thomas S Griffith
- Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA; Department of Urology, University of Minnesota, Minneapolis, MN 55455, USA; Minneapolis VA Health Care System, Minneapolis, MN 55417, USA
| | - Christina D Camell
- Molecular Pharmacology and Therapeutics Graduate Program, Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA; Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA.
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3
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Geppert J, Rohm M. Cancer cachexia: biomarkers and the influence of age. Mol Oncol 2024. [PMID: 38414161 DOI: 10.1002/1878-0261.13590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 12/01/2023] [Accepted: 01/15/2024] [Indexed: 02/29/2024] Open
Abstract
Cancer cachexia (Ccx) is a complex metabolic condition characterized by pronounced muscle and fat wasting, systemic inflammation, weakness and fatigue. Up to 30% of cancer patients succumb directly to Ccx, yet therapies that effectively address this perturbed metabolic state are rare. In recent decades, several characteristics of Ccx have been established in mice and humans, of which we here highlight adipose tissue dysfunction, muscle wasting and systemic inflammation, as they are directly linked to biomarker discovery. To counteract cachexia pathogenesis as early as possible and mitigate its detrimental impact on anti-cancer treatments, identification and validation of clinically endorsed biomarkers assume paramount importance. Ageing was recently shown to affect both the validity of Ccx biomarkers and Ccx development, but the underlying mechanisms are still unknown. Thus, unravelling the intricate interplay between ageing and Ccx can help to counteract Ccx pathogenesis and tailor diagnostic and treatment strategies to individual needs.
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Affiliation(s)
- Julia Geppert
- Institute for Diabetes and Cancer, Helmholtz Munich, Neuherberg, Germany
- Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Maria Rohm
- Institute for Diabetes and Cancer, Helmholtz Munich, Neuherberg, Germany
- Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
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4
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Maestri A, Garagnani P, Pedrelli M, Hagberg CE, Parini P, Ehrenborg E. Lipid droplets, autophagy, and ageing: A cell-specific tale. Ageing Res Rev 2024; 94:102194. [PMID: 38218464 DOI: 10.1016/j.arr.2024.102194] [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: 10/14/2023] [Revised: 12/22/2023] [Accepted: 01/08/2024] [Indexed: 01/15/2024]
Abstract
Lipid droplets are the essential organelle for storing lipids in a cell. Within the variety of the human body, different cells store, utilize and release lipids in different ways, depending on their intrinsic function. However, these differences are not well characterized and, especially in the context of ageing, represent a key factor for cardiometabolic diseases. Whole body lipid homeostasis is a central interest in the field of cardiometabolic diseases. In this review we characterize lipid droplets and their utilization via autophagy and describe their diverse fate in three cells types central in cardiometabolic dysfunctions: adipocytes, hepatocytes, and macrophages.
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Affiliation(s)
- Alice Maestri
- Division of Cardiovascular Medicine, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Paolo Garagnani
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy; IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Matteo Pedrelli
- Cardio Metabolic Unit, Department of Laboratory Medicine, and Department of Medicine (Huddinge), Karolinska Institutet, Stockholm, Sweden; Medicine Unit of Endocrinology, Theme Inflammation and Ageing, Karolinska University Hospital, Stockholm, Sweden
| | - Carolina E Hagberg
- Division of Cardiovascular Medicine, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Paolo Parini
- Cardio Metabolic Unit, Department of Laboratory Medicine, and Department of Medicine (Huddinge), Karolinska Institutet, Stockholm, Sweden; Medicine Unit of Endocrinology, Theme Inflammation and Ageing, Karolinska University Hospital, Stockholm, Sweden
| | - Ewa Ehrenborg
- Division of Cardiovascular Medicine, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.
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5
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Brícola RS, Cordeiro AV, Crisol BM, Braga RR, de Melo DG, Rocha MB, Gaspar RC, Nakandakari SCBR, Silva VRR, Anaruma CP, Katashima CK, Canciglieri RDS, Munõz VR, Pavan ICB, Pinto AP, Simabuco FM, Silva ASRD, Moura LP, Pauli JR, Cintra DE, Ropelle ER. Aging reduces ABHD5 protein content in the adipose tissue of mice: The reversal effect of exercise. Cell Biochem Funct 2023; 41:128-137. [PMID: 36515301 DOI: 10.1002/cbf.3770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/28/2022] [Accepted: 11/19/2022] [Indexed: 12/15/2022]
Abstract
Dysfunction of the adipose tissue metabolism is considered as a significant hallmark of aging. It has been proposed that α-β hydrolase domain containing 5 (ABHD5) plays a critical role in the control of lipolysis. However, the role of ABHD5 in the control of lipolysis during aging or exercise is unknown. Here we combined the experimental mouse model with transcriptomic analyzes by using murine and human databases to explore the role of ABHD5 in the adipose tissue during aging and in response to exercise. Transcriptomic data revealed a downregulation of Abhd5 messenger RNA levels in the subcutaneous white adipose tissue (scWAT) over time in individuals from 20 to 69 years old. Aged mice displayed dramatic reduction of ABHD5 protein content and lipolytic-related proteins in the scWAT. Interestingly, 4 weeks of high-intensity interval training increased ABHD5 protein level and restored the lipolytic pathway in the scWAT of aged mice. Altogether, our findings demonstrated that aging affects ABHD5 content in the adipose tissue of mice and humans. Conversely, exercise increases ABHD5 activity, recovering the lipolytic activity in aged mice.
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Affiliation(s)
- Rafael S Brícola
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil
| | - André V Cordeiro
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil
| | - Barbara M Crisol
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil
| | - Renata R Braga
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil
| | - Diego G de Melo
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil
| | - Matheus B Rocha
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil
| | - Rafael C Gaspar
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil
| | - Susana C B R Nakandakari
- Laboratory of Nutritional Genomics (LabGeN), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil
| | - Vagner R R Silva
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil
| | - Chadi P Anaruma
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil
| | - Carlos K Katashima
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil
| | - Raphael D S Canciglieri
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil
| | - Vitor R Munõz
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil
| | - Isadora C B Pavan
- Multidisciplinary Laboratory of Food and Health, School of Applied Sciences, State University of Campinas, Limeira, São Paulo, Brazil
| | - Ana P Pinto
- Ribeirão Preto Medical School, School of Physical Education and Sport of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Fernando M Simabuco
- Multidisciplinary Laboratory of Food and Health, School of Applied Sciences, State University of Campinas, Limeira, São Paulo, Brazil
| | - Adelino S R da Silva
- Ribeirão Preto Medical School, School of Physical Education and Sport of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Leandro P Moura
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil.,CEPECE-Center of Research in Sport Sciences, School of Applied Sciences, University of Campinas (UNICAMP), Limeira, São Paulo, Brazil
| | - José R Pauli
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil.,CEPECE-Center of Research in Sport Sciences, School of Applied Sciences, University of Campinas (UNICAMP), Limeira, São Paulo, Brazil.,Laboratory of Cell Signaling-Obesity and Comorbidities Research Center, University of Campinas, Campinas, São Paulo, Brazil
| | - Dennys E Cintra
- Laboratory of Nutritional Genomics (LabGeN), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil.,Laboratory of Cell Signaling-Obesity and Comorbidities Research Center, University of Campinas, Campinas, São Paulo, Brazil
| | - Eduardo R Ropelle
- Laboratory of Molecular Biology of Exercise (LaBMEx), School of Applied Sciences, University of Campinas, Limeira, São Paulo, Brazil.,CEPECE-Center of Research in Sport Sciences, School of Applied Sciences, University of Campinas (UNICAMP), Limeira, São Paulo, Brazil.,Laboratory of Cell Signaling-Obesity and Comorbidities Research Center, University of Campinas, Campinas, São Paulo, Brazil.,Department of Internal Medicine, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
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6
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Cai Z, He B. Adipose tissue aging: An update on mechanisms and therapeutic strategies. Metabolism 2023; 138:155328. [PMID: 36202221 DOI: 10.1016/j.metabol.2022.155328] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 09/20/2022] [Accepted: 09/29/2022] [Indexed: 11/06/2022]
Abstract
Aging is a complex biological process characterized by a progressive loss of physiological integrity and increased vulnerability to age-related diseases. Adipose tissue plays central roles in the maintenance of whole-body metabolism homeostasis and has recently attracted significant attention as a biological driver of aging and age-related diseases. Here, we review the most recent advances in our understanding of the molecular and cellular mechanisms underlying age-related decline in adipose tissue function. In particular, we focus on the complex inter-relationship between metabolism, immune, and sympathetic nervous system within adipose tissue during aging. Moreover, we discuss the rejuvenation strategies to delay aging and extend lifespan, including senescent cell ablation (senolytics), dietary intervention, physical exercise, and heterochronic parabiosis. Understanding the pathological mechanisms that underlie adipose tissue aging will be critical for the development of new intervention strategies to slow or reverse aging and age-related diseases.
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Affiliation(s)
- Zhaohua Cai
- Heart Center, Shanghai Chest Hospital, Shanghai Jiaotong University, Shanghai 200030, China
| | - Ben He
- Heart Center, Shanghai Chest Hospital, Shanghai Jiaotong University, Shanghai 200030, China.
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7
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Wang G, Song A, Bae M, Wang QA. Adipose Tissue Plasticity in Aging. Compr Physiol 2022; 12:4119-4132. [PMID: 36214190 DOI: 10.1002/cphy.c220005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
As a dynamic endocrine organ, white adipose tissue (WAT) stores lipids and plays a critical role in maintaining whole-body energy homeostasis and insulin sensitivity. A large group of the population over 65 years old suffer from increased WAT mass, especially in the visceral location. Visceral adiposity accelerates aging through promoting age-associated chronic conditions, significantly shortening life expectancy. Unlike WAT, brown adipose tissue (BAT) functions as an effective energy sink that burns and disposes of excess lipids and glucose upon activation of thermogenesis. Unfortunately, the thermogenic activity of BAT declines during aging. New appreciation of cellular and functional remodeling of WAT and BAT during aging has emerged in recent years. Efforts are underway to explore the potential underlying mechanisms behind these age-associated alterations in WAT and BAT and the impact of these alterations on whole-body metabolism. Lastly, it is intriguing to translate our knowledge obtained from animal models to the clinic to prevent and treat age-associated metabolic disorders. © 2022 American Physiological Society. Compr Physiol 12: 4119-4132, 2022.
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Affiliation(s)
- Guan Wang
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Medical Center, Duarte, California, USA
| | - Anying Song
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Medical Center, Duarte, California, USA
| | - Marie Bae
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Medical Center, Duarte, California, USA
| | - Qiong A Wang
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Medical Center, Duarte, California, USA.,Comprehensive Cancer Center, Beckman Research Institute, City of Hope Medical Center, Duarte, California, USA
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8
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Shang L, Aughey E, Kim H, Heden TD, Wang L, Najt CP, Esch N, Brunko S, Abrahante JE, Macchietto M, Mashek MT, Fairbanks T, Promislow DEL, Neufeld TP, Mashek DG. Systemic lipolysis promotes physiological fitness in Drosophila melanogaster. Aging (Albany NY) 2022; 14:6481-6506. [PMID: 36044277 PMCID: PMC9467406 DOI: 10.18632/aging.204251] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 08/15/2022] [Indexed: 11/25/2022]
Abstract
Since interventions such as caloric restriction or fasting robustly promote lipid catabolism and improve aging-related phenotypical markers, we investigated the direct effect of increased lipid catabolism via overexpression of bmm (brummer, FBgn0036449), the major triglyceride hydrolase in Drosophila, on lifespan and physiological fitness. Comprehensive characterization was carried out using RNA-seq, lipidomics and metabolomics analysis. Global overexpression of bmm strongly promoted numerous markers of physiological fitness, including increased female fecundity, fertility maintenance, preserved locomotion activity, increased mitochondrial biogenesis and oxidative metabolism. Increased bmm robustly upregulated the heat shock protein 70 (Hsp70) family of proteins, which equipped the flies with higher resistance to heat, cold, and ER stress via improved proteostasis. Despite improved physiological fitness, bmm overexpression did not extend lifespan. Taken together, these data show that bmm overexpression has broad beneficial effects on physiological fitness, but these effects did not impact lifespan.
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Affiliation(s)
- Linshan Shang
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Elizabeth Aughey
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Huiseon Kim
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Timothy D Heden
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Lu Wang
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98105, USA
| | - Charles P Najt
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Nicholas Esch
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Sophia Brunko
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Juan E Abrahante
- University of Minnesota Informatics Institute, Minneapolis, MN 55455, USA
| | - Marissa Macchietto
- Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455, USA
| | - Mara T Mashek
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Todd Fairbanks
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Daniel E L Promislow
- Department of Biology, University of Washington, Seattle, WA 98195, USA.,Department of Lab Medicine and Pathology, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Thomas P Neufeld
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Douglas G Mashek
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.,Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, University of Minnesota, Minneapolis, MN 55455, USA
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9
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Thiagarajan D, Quadri N, Jawahar S, Zirpoli H, Del Pozo CH, López-Díez R, Hasan SN, Yepuri G, Gugger PF, Finlin BS, Kern PA, Gabbay K, Schmidt AM, Ramasamy R. Aldose reductase promotes diet-induced obesity via induction of senescence in subcutaneous adipose tissue. Obesity (Silver Spring) 2022; 30:1647-1658. [PMID: 35894077 DOI: 10.1002/oby.23496] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 05/09/2022] [Accepted: 05/12/2022] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Aldose reductase (AKR1B1 in humans; Akr1b3 in mice), a key enzyme of the polyol pathway, mediates lipid accumulation in the murine heart and liver. The study objective was to explore potential roles for AKR1B1/Akr1b3 in the pathogenesis of obesity and its complications. METHODS The study employed mice treated with an inhibitor of aldose reductase or mice devoid of Akr1b3 were used to determine their response to a high-fat diet. The study used subcutaneous adipose tissue-derived adipocytes to investigate mechanisms by which AKR1B1/Akr1b3 promotes diet-induced obesity. RESULTS Increased expression of aldose reductase and senescence in the adipose tissue of humans and mice with obesity were demonstrated. Genetic deletion of Akr1b3 or pharmacological blockade of AKRIB3 with zopolrestat reduced high-fat-diet-induced obesity, attenuated markers of adipose tissue senescence, and increased lipolysis. CONCLUSIONS AKR1B1/Akr1b3 modulation of senescence in subcutaneous adipose tissue contributes to aberrant metabolic responses to high-fat feeding. These data unveil new opportunities to target these pathways to combat obesity.
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Affiliation(s)
- Devi Thiagarajan
- Diabetes Research Program, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
- Saha Cardiovascular Research Center, Department of Physiology, University of Kentucky, Lexington, Kentucky, USA
| | - Nosirudeen Quadri
- Diabetes Research Program, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
| | - Shabnam Jawahar
- Diabetes Research Program, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
| | - Hylde Zirpoli
- Diabetes Research Program, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
| | - Carmen Hurtado Del Pozo
- Diabetes Research Program, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
| | - Raquel López-Díez
- Diabetes Research Program, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
| | - Syed Nurul Hasan
- Diabetes Research Program, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
| | - Gautham Yepuri
- Diabetes Research Program, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
| | - Paul F Gugger
- Diabetes Research Program, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
| | - Brian S Finlin
- Center for Clinical and Translational Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Philip A Kern
- Center for Clinical and Translational Sciences, University of Kentucky, Lexington, Kentucky, USA
| | | | - Ann Marie Schmidt
- Diabetes Research Program, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
| | - Ravichandran Ramasamy
- Diabetes Research Program, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
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10
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Katz MS, Davis PJ. Robert I. Gregerman, MD (1930-2021). An Editorial Reminiscence. Endocr Res 2022; 47:95-103. [PMID: 36101979 DOI: 10.1080/07435800.2022.2120893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Michael S Katz
- Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Paul J Davis
- Department of Medicine, Albany Medical College, Albany, NY, USA
- Pharmaceutical Research Institute, Albany College of Pharmacy and Health Sciences, Rensselaer, NY, USA
- NanoPharmaceuticals LLC, Rensselaer, NY, USA
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11
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Peng W, Zhou R, Sun ZF, Long JW, Gong YQ. Novel Insights into the Roles and Mechanisms of GLP-1 Receptor Agonists against Aging-Related Diseases. Aging Dis 2022; 13:468-490. [PMID: 35371594 PMCID: PMC8947838 DOI: 10.14336/ad.2021.0928] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/16/2021] [Indexed: 11/01/2022] Open
Abstract
Aging and aging-related diseases have emerged as increasingly severe health and social problems. Therefore, it is imperative to discover novel and effective therapeutics to delay the aging process and to manage aging-related diseases. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs), one of the classes of antihyperglycemic drugs, have been recommended to manage type 2 diabetes mellitus (T2DM). Moreover, GLP-1 RAs have been shown to protect against oxidative stress, cellular senescence and chronic inflammation, which are widely accepted as the major risk factors of aging. However, their significance in aging or aging-related diseases has not been elucidated. Herein, we explain the underlying mechanisms and protective roles of GLP-1 RAs in aging from a molecular, cellular and phenotypic perspective. We provide novel insights into the broad prospect of GLP-1 RAs in preventing and treating aging-related diseases. Additionally, we highlight the gaps for further studies in clinical applications of GLP-1 RAs in aging-related diseases. This review forms a basis for further studies on the relationship between aging-related diseases and GLP-1 RAs.
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Affiliation(s)
- Wei Peng
- Department of Gastrointestinal Surgery, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha, Hunan, China
| | - Rui Zhou
- Hunan Normal University School of Medicine, Changsha, Hunan, China.
| | - Ze-Fang Sun
- Hunan Normal University School of Medicine, Changsha, Hunan, China.
| | - Jia-Wei Long
- Hunan Normal University School of Medicine, Changsha, Hunan, China.
| | - Yong-Qiang Gong
- Department of Gastrointestinal Surgery, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha, Hunan, China,Correspondence should be addressed to: Dr. Yong-Qiang Gong, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University, Hunan, China. E-mail:
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12
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Camell CD. Adipose tissue microenvironments during aging: Effects on stimulated lipolysis. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159118. [PMID: 35131468 PMCID: PMC8986088 DOI: 10.1016/j.bbalip.2022.159118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 10/17/2021] [Accepted: 01/20/2022] [Indexed: 12/15/2022]
Abstract
Adipose tissue is a critical organ for nutrient sensing, energy storage and maintaining metabolic health. The failure of adipose tissue homeostasis leads to metabolic disease that is seen during obesity or aging. Local metabolic processes are coordinated by interacting microenvironments that make up the complexity and heterogeneity of the adipose tissue. Catecholamine-induced lipolysis, a critical pathway in adipocytes that drives the release of stored triglyceride as free fatty acid after stimulation, is impaired during aging. The impairment of this pathway is associated with a failure to maintain a healthy body weight, core body-temperature during cold stress or mount an immune response. Along with impairments in aged adipocytes, aging is associated with an accumulation of inflammation, immune cell activation, and increased dysfunction in the nervous and lymphatic systems within the adipose tissue. Together these microenvironments support the initiation of stimulated lipolysis and the transport of free fatty acid under conditions of metabolic homeostasis. However, during aging, the defects in these cellular systems result in a reduction in ability to stimulate lipolysis. This review will focus on how the immune, nervous and lymphatic systems interact during tissue homeostasis, review areas that are impaired with aging and discuss areas of research that are currently unclear.
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Affiliation(s)
- Christina D Camell
- Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, United States of America.
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13
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Ma Y, Liu S, Jun H, Wu J. CHRNA2: a new paradigm in beige thermoregulation and metabolism. Trends Cell Biol 2021; 32:479-489. [PMID: 34952750 DOI: 10.1016/j.tcb.2021.11.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/19/2021] [Accepted: 11/25/2021] [Indexed: 02/07/2023]
Abstract
The contribution of thermogenic adipocytes to maintain systemic metabolic homeostasis has been increasingly appreciated in recent years. It is now recognized that different types (e.g., brown, beige) and subtypes of thermogenic adipocytes may arise from various developmental origins. In addition to the adrenergic pathway, other signals can activate thermogenesis, including paracrine communication between immune cells within the adipose tissue niche and thermogenic adipocytes. In this opinion article we highlight the recently discovered beige-selective signaling between acetylcholine from immune cells and cholinergic receptor nicotinic alpha 2 subunit (CHRNA2) in activated beige adipocytes. We present our current knowledge of how this previously unrecognized adipose non-neuronal cholinergic signaling pathway mediates beige thermoregulation, and discuss its impact on whole-body fitness and its therapeutic potential as a novel target for combating metabolic disease.
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Affiliation(s)
- Yingxu Ma
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Shanshan Liu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Heejin Jun
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jun Wu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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14
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Age and Sex: Impact on adipose tissue metabolism and inflammation. Mech Ageing Dev 2021; 199:111563. [PMID: 34474078 DOI: 10.1016/j.mad.2021.111563] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 08/19/2021] [Accepted: 08/26/2021] [Indexed: 02/08/2023]
Abstract
Age associated chronic inflammation is a major contributor to diseases with advancing age. Adipose tissue function is at the nexus of processes contributing to age-related metabolic disease and mediating longevity. Hormonal fluctuations in aging potentially regulate age-associated visceral adiposity and metabolic dysfunction. Visceral adiposity in aging is linked to aberrant adipogenesis, insulin resistance, lipotoxicity and altered adipokine secretion. Age-related inflammatory phenomena depict sex differences in macrophage polarization, changes in T and B cell numbers, and types of dendritic cells. Sex differences are also observed in adipose tissue remodeling and cellular senescence suggesting a role for sex steroid hormones in the regulation of the adipose tissue microenvironment. It is crucial to investigate sex differences in aging clinical outcomes to identify and better understand physiology in at-risk individuals. Early interventions aimed at targets involved in adipose tissue adipogenesis, remodeling and inflammation in aging could facilitate a profound impact on health span and overcome age-related functional decline.
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15
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Shi Y, Pizzini J, Wang H, Das F, Abdul Azees PA, Ghosh Choudhury G, Barnes JL, Zang M, Weintraub ST, Yeh CK, Katz MS, Kamat A. β2-Adrenergic receptor agonist induced hepatic steatosis in mice: modeling nonalcoholic fatty liver disease in hyperadrenergic states. Am J Physiol Endocrinol Metab 2021; 321:E90-E104. [PMID: 34029162 PMCID: PMC8321826 DOI: 10.1152/ajpendo.00651.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 04/23/2021] [Accepted: 05/08/2021] [Indexed: 12/11/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a spectrum of disorders ranging from hepatic steatosis [excessive accumulation of triglycerides (TG)] to nonalcoholic steatohepatitis, which can progress to cirrhosis and hepatocellular carcinoma. The molecular pathogenesis of steatosis and progression to more severe NAFLD remains unclear. Obesity and aging, two principal risk factors for NAFLD, are associated with a hyperadrenergic state. β-Adrenergic responsiveness in liver increases in animal models of obesity and aging, and in both is linked to increased hepatic expression of β2-adrenergic receptors (β2-ARs). We previously showed that in aging rodents intracellular signaling from elevated hepatic levels of β2-ARs may contribute to liver steatosis. In this study we demonstrate that injection of formoterol, a highly selective β2-AR agonist, to mice acutely results in hepatic TG accumulation. Further, we have sought to define the intrahepatic mechanisms underlying β2-AR mediated steatosis by investigating changes in hepatic expression and cellular localization of enzymes, transcription factors, and coactivators involved in processes of lipid accrual and disposition-and also functional aspects thereof-in livers of formoterol-treated animals. Our results suggest that β2-AR activation by formoterol leads to increased hepatic TG synthesis and de novo lipogenesis, increased but incomplete β-oxidation of fatty acids with accumulation of potentially toxic long-chain acylcarnitine intermediates, and reduced TG secretion-all previously invoked as contributors to fatty liver disease. Experiments are ongoing to determine whether sustained activation of hepatic β2-AR signaling by formoterol might be utilized to model fatty liver changes occurring in hyperadrenergic states of obesity and aging, and thereby identify novel molecular targets for the prevention or treatment of NAFLD.NEW & NOTEWORTHY Results of our study suggest that β2-adrenergic receptor (β2-AR) activation by agonist formoterol leads to increased hepatic TG synthesis and de novo lipogenesis, incomplete β-oxidation of fatty acids with accumulation of long-chain acylcarnitine intermediates, and reduced TG secretion. These findings may, for the first time, implicate a role for β2-AR responsive dysregulation of hepatic lipid metabolism in the pathogenetic processes underlying NAFLD in hyperadrenergic states such as obesity and aging.
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Affiliation(s)
- Yun Shi
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Jason Pizzini
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Hanzhou Wang
- Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Falguni Das
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Parveez Ahamed Abdul Azees
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
- Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Goutam Ghosh Choudhury
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Jeffrey L Barnes
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Mengwei Zang
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, Texas
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, Texas
| | - Susan T Weintraub
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Chih-Ko Yeh
- Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, Texas
| | - Michael S Katz
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, Texas
| | - Amrita Kamat
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, Texas
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16
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De Luca M, Mandala M, Rose G. Towards an understanding of the mechanoreciprocity process in adipocytes and its perturbation with aging. Mech Ageing Dev 2021; 197:111522. [PMID: 34147549 DOI: 10.1016/j.mad.2021.111522] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 05/29/2021] [Accepted: 06/15/2021] [Indexed: 12/25/2022]
Abstract
Adipose tissue (AT) is a complex organ, with multiple functions that are essential for maintaining metabolic health. A feature of AT is its capability to expand in response to physiological challenges, such as pregnancy and aging, and during chronic states of positive energy balance occurring throughout life. AT grows through adipogenesis and/or an increase in the size of existing adipocytes. One process that is required for healthy AT growth is the remodeling of the extracellular matrix (ECM), which is a necessary step to restore mechanical homeostasis and maintain tissue integrity and functionality. While the relationship between mechanobiology and adipogenesis is now well recognized, less is known about the role of adipocyte mechanosignaling pathways in AT growth. In this review article, we first summarize evidence linking ECM remodelling to AT expansion and how its perturbation is associated to a metabolically unhealthy phenotype. Subsequently, we highlight findings suggesting that molecules involved in the dynamic, bidirectional process (mechanoreciprocity) enabling adipocytes to sense changes in the mechanical properties of the ECM are interconnected to pathways regulating lipid metabolism. Finally, we discuss processes through which aging may influence the ability of adipocytes to appropriately respond to alterations in ECM composition.
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Affiliation(s)
- Maria De Luca
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Maurizio Mandala
- Department of Biology, Ecology and Earth Science, University of Calabria, Rende, 87036, Italy
| | - Giuseppina Rose
- Department of Biology, Ecology and Earth Science, University of Calabria, Rende, 87036, Italy
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17
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Nrf2 contributes to the weight gain of mice during space travel. Commun Biol 2020; 3:496. [PMID: 32901092 PMCID: PMC7479603 DOI: 10.1038/s42003-020-01227-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 08/13/2020] [Indexed: 12/27/2022] Open
Abstract
Space flight produces an extreme environment with unique stressors, but little is known about how our body responds to these stresses. While there are many intractable limitations for in-flight space research, some can be overcome by utilizing gene knockout-disease model mice. Here, we report how deletion of Nrf2, a master regulator of stress defense pathways, affects the health of mice transported for a stay in the International Space Station (ISS). After 31 days in the ISS, all flight mice returned safely to Earth. Transcriptome and metabolome analyses revealed that the stresses of space travel evoked ageing-like changes of plasma metabolites and activated the Nrf2 signaling pathway. Especially, Nrf2 was found to be important for maintaining homeostasis of white adipose tissues. This study opens approaches for future space research utilizing murine gene knockout-disease models, and provides insights into mitigating space-induced stresses that limit the further exploration of space by humans. Using Nrf2 knockout mice, Suzuki, Uruno, Yumoto et al. show that space travel activates Nrf2 signaling, which contributes to the weight gain of mice by regulating fat metabolism of white adipose tissues. This study provides insights into potential interventions to mitigate stresses that accompany space travels.
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18
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Frasca D, Blomberg BB. Adipose tissue, immune aging, and cellular senescence. Semin Immunopathol 2020; 42:573-587. [PMID: 32785750 DOI: 10.1007/s00281-020-00812-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/28/2020] [Indexed: 12/14/2022]
Abstract
Obesity represents a serious health problem as it is rapidly increasing worldwide. Obesity is associated with reduced healthspan and lifespan, decreased responses to infections and vaccination, and increased frequency of inflammatory conditions typical of old age. Obesity is characterized by increased fat mass and remodeling of the adipose tissue (AT). In this review, we summarize published data on the different types of AT present in mice and humans, and their roles as fat storage as well as endocrine and immune tissues. We review the age-induced changes, including those in the distribution of fat in the body, in abundance and function of adipocytes and their precursors, and in the infiltration of immune cells from the peripheral blood. We also show that cells with a senescent-associated secretory phenotype accumulate in the AT of mice and humans with age, where they secrete several factors involved in the establishment and maintenance of local inflammation, oxidative stress, cell death, tissue remodeling, and infiltration of pro-inflammatory immune cells. Not only adipocytes and pre-adipocytes but also immune cells show a senescent phenotype in the AT. With the increase in human lifespan, it is crucial to identify strategies of intervention and target senescent cells in the AT to reduce local and systemic inflammation and the development of age-associated diseases. Several studies have indeed shown that senescent cells can be effectively targeted in the AT by selectively removing them or by inhibiting the pathways that lead to the secretion of pro-inflammatory factors.
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Affiliation(s)
- Daniela Frasca
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, USA. .,Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA.
| | - Bonnie B Blomberg
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, USA.,Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA
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19
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Associations of GlycA and high-sensitivity C-reactive protein with measures of lipolysis in adults with obesity. J Clin Lipidol 2020; 14:667-674. [PMID: 32863171 DOI: 10.1016/j.jacl.2020.07.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/21/2020] [Accepted: 07/28/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Obesity-associated inflammation promotes metabolic dysfunction. However, it is unclear how different inflammatory biomarkers predict dysregulation in specific tissues/organs, particularly adipose tissue. OBJECTIVE The aim of our study was to examine whether GlycA, a nuclear magnetic resonance-measured biomarker of inflammation, is a better predictor of insulin-suppressible lipolysis and other measures of metabolic dysfunction compared with high-sensitivity C-reactive protein (hsCRP) in human obesity. METHODS This was a cross-sectional study of 58 nondiabetic adults with obesity (body mass index: 39.8 ± 7.0 kg/m2, age 46.5 ± 12.2 years, 67.2% female) who underwent a frequently sampled intravenous glucose tolerance test in the fasted state. Noninsulin-suppressible (l0), insulin-suppressible (l2), and maximal (l0+l2) lipolysis rates, as well as insulin sensitivity and acute insulin response to glucose, were calculated by minimal model analysis. Nuclear magnetic resonance was used to measure GlycA. Body composition was determined by dual-energy X-ray absorptiometry. RESULTS GlycA was strongly correlated with hsCRP (r = +0.46; P < .001). GlycA and hsCRP were positively associated with l2, l0+l2, and fat mass (Ps < .01). In linear regression models accounting for age, race, sex, and fat mass, GlycA remained significantly associated with l2 and l0+l2 (Ps < .05), whereas hsCRP did not (Ps ≥ .20). Neither GlycA nor hsCRP was associated with l0, insulin sensitivity, or acute insulin response to glucose. CONCLUSIONS GlycA was associated with elevated lipolysis, independent of adiposity, in adults with obesity. Our findings suggest that GlycA and hsCRP have distinct inflammation-mediated metabolic effects, with GlycA having a greater association with adipose tissue dysfunction. Further studies are warranted to investigate the mechanisms underlying these associations.
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20
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Gao H, Arner P, Beauchef G, Guéré C, Vie K, Dahlman I, Mejhert N, Rydén M. Age-Induced Reduction in Human Lipolysis: A Potential Role for Adipocyte Noradrenaline Degradation. Cell Metab 2020; 32:1-3. [PMID: 32589948 DOI: 10.1016/j.cmet.2020.06.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/26/2020] [Accepted: 06/10/2020] [Indexed: 12/13/2022]
Abstract
Gao et al. report that the observed reduction in adipose lipolysis with age in women could be explained by an upregulation of the catecholamine-degradation pathway in subcutaneous adipocytes. However, in contrast to findings in mice, these pathways are enriched in adipocytes and not in immune cells, suggesting species-specific differences in aging mechanisms.
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Affiliation(s)
- Hui Gao
- Department of Biosciences and Nutrition (H2), Karolinska Institutet, Huddinge 141 83, Sweden
| | - Peter Arner
- Department of Medicine (H7), Karolinska Institutet, Karolinska University Hospital, Huddinge, 141 86 Stockholm, Sweden
| | | | | | - Katell Vie
- CLARINS Laboratoires, 95300 Pontoise, France
| | - Ingrid Dahlman
- Department of Medicine (H7), Karolinska Institutet, Karolinska University Hospital, Huddinge, 141 86 Stockholm, Sweden
| | - Niklas Mejhert
- Department of Medicine (H7), Karolinska Institutet, Karolinska University Hospital, Huddinge, 141 86 Stockholm, Sweden
| | - Mikael Rydén
- Department of Medicine (H7), Karolinska Institutet, Karolinska University Hospital, Huddinge, 141 86 Stockholm, Sweden.
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21
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Spitler KM, Davies BSJ. Aging and plasma triglyceride metabolism. J Lipid Res 2020; 61:1161-1167. [PMID: 32586846 DOI: 10.1194/jlr.r120000922] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/11/2020] [Indexed: 12/16/2022] Open
Abstract
The risk for metabolic disease, including metabolic syndrome, insulin resistance, and diabetes, increases with age. Altered plasma TG metabolism and changes in fatty acid partitioning are also major contributors to metabolic disease. Plasma TG metabolism itself is altered by age in humans and rodents. As discussed in this review, the age-induced changes in human TG metabolism include increased plasma TG levels, reduced postprandial plasma TG clearance rates, reduced postheparin LPL activity, decreased adipose tissue lipolysis, and elevated ectopic fat deposition, all of which could potentially contribute to age-associated metabolic diseases. Similar observations have been made in aged rats. We highlight the limitations of currently available data and propose that mechanistic studies are needed to understand the extent to which age-induced alterations in TG metabolism contribute to metabolic disease. Such mechanistic insights could aid in therapeutic strategies for preventing or managing metabolic disease in older individuals.
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Affiliation(s)
- Kathryn M Spitler
- Department of Biochemistry, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa Carver College of Medicine, Iowa City, IA 52242
| | - Brandon S J Davies
- Department of Biochemistry, Fraternal Order of Eagles Diabetes Research Center, and Obesity Research and Education Initiative, University of Iowa Carver College of Medicine, Iowa City, IA 52242
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22
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Jun H, Ma Y, Chen Y, Gong J, Liu S, Wang J, Knights AJ, Qiao X, Emont MP, Xu XZS, Kajimura S, Wu J. Adrenergic-Independent Signaling via CHRNA2 Regulates Beige Fat Activation. Dev Cell 2020; 54:106-116.e5. [PMID: 32533922 DOI: 10.1016/j.devcel.2020.05.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 03/17/2020] [Accepted: 05/14/2020] [Indexed: 11/28/2022]
Abstract
Maintaining energy homeostasis upon environmental challenges, such as cold or excess calorie intake, is essential to the fitness and survival of mammals. Drug discovery efforts targeting β-adrenergic signaling have not been fruitful after decades of intensive research. We recently identified a new beige fat regulatory pathway mediated via the nicotinic acetylcholine receptor subunit CHRNA2. Here, we generated fat-specific Chrna2 KO mice and observed thermogenic defects in cold and metabolic dysfunction upon dietary challenges caused by adipocyte-autonomous regulation in vivo. We found that CHRNA2 signaling is activated after acute high fat diet feeding and this effect is manifested through both UCP1- and creatine-mediated mechanisms. Furthermore, our data suggested that CHRNA2 signaling may activate glycolytic beige fat, a subpopulation of beige adipocytes mediated by GABPα emerging in the absence of β-adrenergic signaling. These findings reveal the biological significance of the CHRNA2 pathway in beige fat biogenesis and energy homeostasis.
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Affiliation(s)
- Heejin Jun
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yingxu Ma
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Cardiology, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410013, China
| | - Yong Chen
- UCSF Diabetes Center, San Francisco, CA, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA; Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA
| | - Jianke Gong
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Sciences and Technology, and Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Shanshan Liu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jine Wang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Xiaona Qiao
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Margo P Emont
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - X Z Shawn Xu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Shingo Kajimura
- UCSF Diabetes Center, San Francisco, CA, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA; Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA
| | - Jun Wu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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Myocardium Metabolism in Physiological and Pathophysiological States: Implications of Epicardial Adipose Tissue and Potential Therapeutic Targets. Int J Mol Sci 2020; 21:ijms21072641. [PMID: 32290181 PMCID: PMC7177518 DOI: 10.3390/ijms21072641] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/05/2020] [Accepted: 04/08/2020] [Indexed: 01/01/2023] Open
Abstract
The main energy substrate of adult cardiomyocytes for their contractility are the fatty acids. Its metabolism generates high ATP levels at the expense of high oxygen consumption in the mitochondria. Under low oxygen supply, they can get energy from other substrates, mainly glucose, lactate, ketone bodies, etc., but the mitochondrial dysfunction, in pathological conditions, reduces the oxidative metabolism. In consequence, fatty acids are stored into epicardial fat and its accumulation provokes inflammation, insulin resistance, and oxidative stress, which enhance the myocardium dysfunction. Some therapies focused on improvement the fatty acids entry into mitochondria have failed to demonstrate benefits on cardiovascular disorders. Oppositely, those therapies with effects on epicardial fat volume and inflammation might improve the oxidative metabolism of myocardium and might reduce the cardiovascular disease progression. This review aims at explain (a) the energy substrate adaptation of myocardium in physiological conditions, (b) the reduction of oxidative metabolism in pathological conditions and consequences on epicardial fat accumulation and insulin resistance, and (c) the reduction of cardiovascular outcomes after regulation by some therapies.
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Rydén M, Gao H, Arner P. Influence of Aging and Menstrual Status on Subcutaneous Fat Cell Lipolysis. J Clin Endocrinol Metab 2020; 105:5648098. [PMID: 31784744 DOI: 10.1210/clinem/dgz245] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 11/28/2019] [Indexed: 12/11/2022]
Abstract
CONTEXT Aging is accompanied by inhibited fat cell mobilization of fatty acids through lipolysis, which may contribute to decreased energy expenditure in elderly subjects. However, the influence of menstrual status is unknown. OBJECTIVE To investigate the role of menstrual status on changes in lipolysis induced by aging. DESIGN A longitudinal investigation with a mean 13-year interval. SETTING Ambulatory study at a clinical academic unit. PARTICIPANTS Eighty-two continuously recruited women between 24 and 62 years of age and with body mass index 21 to 48 kg/m2 at first examination. Twenty-nine women continued to have normal menstruation, 42 developed irregular menstruation/menopause, and 11 had a perimenstrual/menopausal phenotype already at the first examination. MAIN OUTCOME MEASURE Lipolysis measured as glycerol release from isolated subcutaneous fat cells incubated in vitro. RESULTS On average, body weight/body fat mass levels did not change over time. In all 3 groups, aging was associated with a similar decrease in spontaneous (basal) and catecholamine-stimulated lipolysis. The latter was due to decreased signal transduction through stimulatory beta adrenoceptors and increased alpha-2-adrenoceptor-mediated antilipolytic effects. Gene microarray data from adipose tissue at baseline and follow-up (n = 53) showed that a limited set of lipolysis-linked genes, including phosphodiesterase-3B, were altered over time, but this was independent of menstrual status. Fat cell size also decreased during aging, but this could not explain the decrease in lipolysis. CONCLUSIONS In women, the rate of fat cell lipolysis decreases during aging due to multiple alterations in spontaneous (basal) and catecholamine-induced lipolysis. This is independent of changes in menstrual status or fat cell size.
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Affiliation(s)
- Mikael Rydén
- Department of Medicine (H7), Karolinska Institutet at Karolinska University Hospital-Huddinge, Stockholm, Sweden
| | - Hui Gao
- Department of Medicine (H7), Karolinska Institutet at Karolinska University Hospital-Huddinge, Stockholm, Sweden
| | - Peter Arner
- Department of Medicine (H7), Karolinska Institutet at Karolinska University Hospital-Huddinge, Stockholm, Sweden
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Adipose tissue NAD + biosynthesis is required for regulating adaptive thermogenesis and whole-body energy homeostasis in mice. Proc Natl Acad Sci U S A 2019; 116:23822-23828. [PMID: 31694884 DOI: 10.1073/pnas.1909917116] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) is a critical coenzyme for cellular energy metabolism. The aim of the present study was to determine the importance of brown and white adipose tissue (BAT and WAT) NAD+ metabolism in regulating whole-body thermogenesis and energy metabolism. Accordingly, we generated and analyzed adipocyte-specific nicotinamide phosphoribosyltransferase (Nampt) knockout (ANKO) and brown adipocyte-specific Nampt knockout (BANKO) mice because NAMPT is the rate-limiting NAD+ biosynthetic enzyme. We found ANKO mice, which lack NAMPT in both BAT and WAT, had impaired gene programs involved in thermogenesis and mitochondrial function in BAT and a blunted thermogenic (rectal temperature, BAT temperature, and whole-body oxygen consumption) response to acute cold exposure, prolonged fasting, and administration of β-adrenergic agonists (norepinephrine and CL-316243). In addition, the absence of NAMPT in WAT markedly reduced adrenergic-mediated lipolytic activity, likely through inactivation of the NAD+-SIRT1-caveolin-1 axis, which limits an important fuel source fatty acid for BAT thermogenesis. These metabolic abnormalities were rescued by treatment with nicotinamide mononucleotide (NMN), which bypasses the block in NAD+ synthesis induced by NAMPT deficiency. Although BANKO mice, which lack NAMPT in BAT only, had BAT cellular alterations similar to the ANKO mice, BANKO mice had normal thermogenic and lipolytic responses. We also found NAMPT expression in supraclavicular adipose tissue (where human BAT is localized) obtained from human subjects increased during cold exposure, suggesting our finding in rodents could apply to people. These results demonstrate that adipose NAMPT-mediated NAD+ biosynthesis is essential for regulating adaptive thermogenesis, lipolysis, and whole-body energy metabolism.
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26
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Adipose lipid turnover and long-term changes in body weight. Nat Med 2019; 25:1385-1389. [DOI: 10.1038/s41591-019-0565-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 07/30/2019] [Indexed: 01/08/2023]
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27
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Sugimoto D, Tamura Y, Takeno K, Kaga H, Someya Y, Kakehi S, Funayama T, Furukawa Y, Suzuki R, Kadowaki S, Nishitani-Yokoyama M, Shimada K, Daida H, Aoki S, Kanazawa A, Kawamori R, Watada H. Clinical Features of Nonobese, Apparently Healthy, Japanese Men With Reduced Adipose Tissue Insulin Sensitivity. J Clin Endocrinol Metab 2019; 104:2325-2333. [PMID: 30689902 DOI: 10.1210/jc.2018-02190] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 01/18/2019] [Indexed: 12/23/2022]
Abstract
CONTEXT Adipose tissue insulin resistance has been observed in obese subjects and is considered an early metabolic defect that precedes insulin resistance in muscle and liver. Although Asians can readily develop metabolic disease without obesity, the clinical features of nonobese, apparently healthy, Asians with reduced adipose tissue insulin sensitivity (ATIS) have not been elucidated. OBJECTIVE To investigate the clinical parameters associated with reduced ATIS in nonobese, apparently healthy (body mass index <25 kg/m2), Japanese men. METHODS We studied 52 nonobese Japanese men without cardiometabolic risk factors. Using a two-step hyperinsulinemic euglycemic clamp with a glucose tracer, we evaluated the insulin sensitivity in muscle, liver, and adipose tissue. ATIS was calculated as the percentage of free fatty acid (FFA) suppression/insulin concentration during the first step of the glucose clamp. RESULTS Using the median ATIS value, the subjects were divided into low- and high-FFA suppression groups. The low-FFA suppression group had moderate fat accumulation in the abdominal subcutaneous adipose tissue and liver. Compared with the high-FFA group, they also had a lower fitness level, decreased insulin clearance, impaired insulin sensitivity in muscle, moderately elevated triglycerides, and lowered high-density lipoprotein cholesterol levels. All these factors correlated significantly with ATIS. Hepatic insulin sensitivity was comparable between the two groups. CONCLUSIONS In nonobese, apparently healthy, Japanese men, reduced ATIS was associated with moderate fat accumulation in subcutaneous fat and liver, lower insulin clearance, muscle insulin resistance, and moderate lipedema. These data suggest that reduced ATIS can occur early in the development of the metabolic syndrome, even in nonobese, apparently healthy, men.
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Affiliation(s)
- Daisuke Sugimoto
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yoshifumi Tamura
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Sportology Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Kageumi Takeno
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Sportology Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Hideyoshi Kaga
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yuki Someya
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Sportology Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Saori Kakehi
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Sportology Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Takashi Funayama
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yasuhiko Furukawa
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Ruriko Suzuki
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Satoshi Kadowaki
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | | | - Kazunori Shimada
- Sportology Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Department of Cardiology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Hiroyuki Daida
- Sportology Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Department of Cardiology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Shigeki Aoki
- Sportology Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Department of Radiology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Akio Kanazawa
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Ryuzo Kawamori
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Sportology Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Hirotaka Watada
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Sportology Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Center for Identification of Diabetic Therapeutic Targets, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Center for Molecular Diabetology, Juntendo University Graduate School of Medicine, Tokyo, Japan
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28
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Muo IM, MacDonald SD, Madan R, Park SJ, Gharib AM, Martinez PE, Walter MF, Yang SB, Rodante JA, Courville AB, Walter PJ, Cai H, Glicksman M, Guerrieri GM, Ben-Dor RR, Ouwerkerk R, Mao S, Chung JH. Early effects of roflumilast on insulin sensitivity in adults with prediabetes and overweight/obesity involve age-associated fat mass loss - results of an exploratory study. Diabetes Metab Syndr Obes 2019; 12:743-759. [PMID: 31213865 PMCID: PMC6542328 DOI: 10.2147/dmso.s182953] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Roflumilast (Daliresp, Daxas) is a FDA-approved phosphodiesterase 4 (PDE4) inhibitor for the treatment of moderate-to-severe chronic obstructive pulmonary disease. In mice and in limited human studies, this oral medication can cause weight loss and improve insulin sensitivity. We set out to determine the mechanism of its effect on insulin sensitivity. PATIENTS AND METHODS Eight adults with overweight/obesity and prediabetes received roflumilast for 6 weeks. Before and after roflumilast, subjects underwent tests of insulin sensitivity, mixed meal test, body composition, markers of inflammation, and mitochondria function. Dietary intake and physical activity were also assessed. Our primary outcome was the change in peripheral insulin sensitivity, as assessed by the hyper-insulinemic euglycemic clamp. RESULTS This study was underpowered for the primary outcome. Pre- and post-roflumilast mean peripheral insulin sensitivity were 48.7 and 70.0 mg/g fat free mass/minute, respectively, (P-value=0.18), respectively. Among the mixed meal variables, roflumilast altered glucagon-like peptide 1 (GLP-1) hormone the most, although the average effect was not statistically significant (P=0.18). Roflumilast induced a trend toward significance in 1) decreased energy intake (from 11,095 KJ to 8,4555 KJ, P=0.07), 2) decreased fat mass (from 34.53 to 32.97 kg, P=0.06), 3) decreased total and LDL cholesterol (P=0.06 for both variables), and 4) increased plasma free fatty acids (from 0.40 to 0.50 mEq/L, P=0.09) The interval changes in adiposity and free fatty acid were significantly associated with the subject's age (P-value range= <0.001 to 0.02 for the correlations). Inflammatory and adhesion markers, though unchanged, significantly correlated with one another and with incretin hormones only after roflumilast. CONCLUSION We demonstrate, for the first time in humans, increasing percentage of fat mass loss from roflumilast with increasing age in adults with prediabetes and overweight/obesity. We also demonstrate novel associations among roflumilast-induced changes in incretin hormones, inflammatory markers, peripheral insulin sensitivity, and adiposity. We conclude that roflumilast's early effects on insulin sensitivity is indirect and likely mediated through roflumilast's prioritization of lipid over glucose handling. CLINICAL TRIALS REGISTRATION NCT01862029.
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Affiliation(s)
- Ijeoma M Muo
- Laboratory of Obesity and Aging Research NHLBI, National Institutes of Health, Bethesda, MD 20892, USA, ,
| | - Sandra D MacDonald
- NHLBI Pulmonary Branch, Laboratory of Chronic Airway Infections, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ritu Madan
- Diabetes Endocrinology and Obesity Branch, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sung-Jun Park
- Laboratory of Obesity and Aging Research NHLBI, National Institutes of Health, Bethesda, MD 20892, USA, ,
| | - Ahmed M Gharib
- Biomedical and Metabolic Imaging Branch NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Pedro E Martinez
- Section on Behavioral Endocrinology, NIMH, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mary F Walter
- Diabetes Endocrinology and Obesity Branch, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shanna B Yang
- Clinical Center Nutrition Department, National Institutes of Health, Bethesda, MD 20892, USA
| | - Justin A Rodante
- Laboratory of Inflammation and Cardiometabolic Diseases, NHLBI, National Institutes of Health, Bethesda, MD 20892, USA
| | - Amber B Courville
- Clinical Center Nutrition Department, National Institutes of Health, Bethesda, MD 20892, USA
| | - Peter J Walter
- Mass Spectrometry Clinical Core, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hongyi Cai
- Mass Spectrometry Clinical Core, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Michael Glicksman
- Diabetes Endocrinology and Obesity Branch, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gioia M Guerrieri
- Section on Behavioral Endocrinology, NIMH, National Institutes of Health, Bethesda, MD 20892, USA
| | - Rivka R Ben-Dor
- NIMH, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ronald Ouwerkerk
- Biomedical and Metabolic Imaging Branch NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Stephanie Mao
- Laboratory of Obesity and Aging Research NHLBI, National Institutes of Health, Bethesda, MD 20892, USA, ,
| | - Jay H Chung
- Laboratory of Obesity and Aging Research NHLBI, National Institutes of Health, Bethesda, MD 20892, USA, ,
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29
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NLRP3 inflammasome activation in inflammaging. Semin Immunol 2018; 40:61-73. [PMID: 30268598 DOI: 10.1016/j.smim.2018.09.001] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/17/2018] [Accepted: 09/18/2018] [Indexed: 02/06/2023]
Abstract
The process of aging is associated with the appearance of low-grade subclinical inflammation, termed inflammaging, that can accelerate age-related diseases. In Western societies the age-related inflammatory response can additionally be aggravated by an inflammatory response related to modern lifestyles and excess calorie consumption, a pathophysiologic inflammatory response that was coined metaflammation. Here, we summarize the current knowledge of mechanisms that drive both of these processes and focus our discussion the emerging concept that a key innate immune pathway, the NLRP3 inflammasome, is centrally involved in the recognition of triggers that appear during physiological aging and during metabolic stress. We further discuss how these processes are involved in the pathogenesis of common age-related pathologies and highlight potential strategies by which the detrimental inflammatory responses could be pharmacologically addressed.
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30
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Abstract
Aging and diabetes mellitus are 2 well-known risk factors for cardiovascular disease (CVD). During the past 50 years, there has been an dramatic increase in life expectancy with a simultaneous increase in the prevalence of diabetes mellitus in the older population. This large number of older individuals with diabetes mellitus is problematic given that CVD risk associated with aging and diabetes mellitus. In this review, we summarize epidemiological data relating to diabetes mellitus and CVD, with an emphasis on the aging population. We then present data on hyperglycemia as a risk factor for CVD and review the current knowledge of age-related changes in glucose metabolism. Next, we review the role of obesity in the pathogenesis of age-related glucose dysregulation, followed by a summary of the results from major randomized controlled trials that focus on cardiovascular risk reduction through glycemic control, with a special emphasis on older adults. We then conclude with our proposed model of aging that body composition changes and insulin resistance link possible dysregulation of physiological pathways leading to obesity and diabetes mellitus-both forms of accelerated aging-and risks for CVD.
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Affiliation(s)
- Chee W Chia
- From the Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Josephine M Egan
- From the Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Luigi Ferrucci
- From the Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD
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31
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Arner P, Andersson DP, Bäckdahl J, Dahlman I, Rydén M. Weight Gain and Impaired Glucose Metabolism in Women Are Predicted by Inefficient Subcutaneous Fat Cell Lipolysis. Cell Metab 2018; 28:45-54.e3. [PMID: 29861390 DOI: 10.1016/j.cmet.2018.05.004] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/13/2018] [Accepted: 05/03/2018] [Indexed: 12/14/2022]
Abstract
Adipocyte mobilization of fatty acids (lipolysis) is instrumental for energy expenditure. Lipolysis displays both spontaneous (basal) and hormone-stimulated activity. It is unknown if lipolysis is important for future body weight gain and associated disturbed glucose metabolism, and this was presently investigated in subcutaneous adipocytes from two female cohorts before and after ≥10-year follow-up. High basal and low stimulated lipolysis at baseline predicted future weight gain (odds ratios ≥4.6) as well as development of insulin resistance and impaired fasting glucose/type 2 diabetes (odds ratios ≥3.2). At baseline, weight gainers displayed lower adipose expression of several established lipolysis-regulating genes. Thus, inefficient lipolysis (high basal/low stimulated) involving altered gene expression is linked to future weight gain and impaired glucose metabolism and may constitute a treatment target. Finally, low stimulated lipolysis could be accurately estimated in vivo by simple clinical/biochemical measures and may be used to identify risk individuals for intensified preventive measures.
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Affiliation(s)
- Peter Arner
- Department of Medicine (H7), Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm 141 86, Sweden.
| | - Daniel P Andersson
- Department of Medicine (H7), Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm 141 86, Sweden
| | - Jesper Bäckdahl
- Department of Medicine (H7), Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm 141 86, Sweden
| | - Ingrid Dahlman
- Department of Medicine (H7), Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm 141 86, Sweden
| | - Mikael Rydén
- Department of Medicine (H7), Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm 141 86, Sweden.
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32
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Yardley JE, Brockman NK, Bracken RM. Could Age, Sex and Physical Fitness Affect Blood Glucose Responses to Exercise in Type 1 Diabetes? Front Endocrinol (Lausanne) 2018; 9:674. [PMID: 30524371 PMCID: PMC6262398 DOI: 10.3389/fendo.2018.00674] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/29/2018] [Indexed: 12/17/2022] Open
Abstract
Closed-loop systems for patients with type 1 diabetes are progressing rapidly. Despite these advances, current systems may struggle in dealing with the acute stress of exercise. Algorithms to predict exercise-induced blood glucose changes in current systems are mostly derived from data involving relatively young, fit males. Little is known about the magnitude of confounding variables such as sex, age, and fitness level-underlying, uncontrollable factors that might influence blood glucose control during exercise. Sex-related differences in hormonal responses to physical exercise exist in studies involving individuals without diabetes, and result in altered fuel metabolism during exercise. Increasing age is associated with attenuated catecholamine responses and lower carbohydrate oxidation during activity. Furthermore, higher fitness levels can alter hormonal and fuel selection responses to exercise. Compounding the limited research on these factors in the metabolic response to exercise in type 1 diabetes is a limited understanding of how these variables affect blood glucose levels during different types, timing and intensities of activity in individuals with type 1 diabetes (T1D). Thus, there is currently insufficient information to model a closed-loop system that can predict them accurately and consistently prevent hypoglycemia. Further, studies involving both sexes, along with a range of ages and fitness levels, are needed to create a closed-loop system that will be more precise in regulating blood glucose during exercise in a wide variety of individuals with T1D.
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Affiliation(s)
- Jane E. Yardley
- Augustana Faculty, University of Alberta, Camrose, AB, Canada
- Physical Activity and Diabetes Laboratory, Alberta Diabetes Institute, Edmonton, AB, Canada
- Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, AB, Canada
- *Correspondence: Jane E. Yardley
| | | | - Richard M. Bracken
- Diabetes Research Unit and School of Sport and Exercise Science, Swansea University, Swansea, United Kingdom
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Camell CD, Sander J, Spadaro O, Lee A, Nguyen KY, Wing A, Goldberg EL, Youm YH, Brown CW, Elsworth J, Rodeheffer MS, Schultze JL, Dixit VD. Inflammasome-driven catecholamine catabolism in macrophages blunts lipolysis during ageing. Nature 2017; 550:119-123. [PMID: 28953873 PMCID: PMC5718149 DOI: 10.1038/nature24022] [Citation(s) in RCA: 296] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 08/21/2017] [Indexed: 12/19/2022]
Abstract
Catecholamine-induced lipolysis, the first step in generation of energy substrates through hydrolysis of triglycerides (TGs) 1, declines with age 2,3. The defect in mobilization of free fatty acids (FFA) in elderly is accompanied with increased visceral adiposity, lower exercise capacity, failure to maintain core body temperature during cold stress, and reduced ability to survive starvation. While catecholamine signaling in adipocytes is normal in elderly, how lipolysis is impaired in aging remains unknown 2,4. Here we uncover that the adipose tissue macrophages (ATMs) regulate age-related reduction in adipocyte lipolysis by lowering the bioavailability of norepinephrine (NE). Unexpectedly, unbiased whole transcriptome analyses of adipose macrophages revealed that aging upregulates genes controlling catecholamine degradation in an NLRP3 inflammasome-dependent manner. Deletion of NLRP3 in aging restored catecholamine-induced lipolysis through downregulation of growth differentiation factor-3 (GDF3) and monoamine oxidase-a (MAOA) that is known to degrade NE. Consistent with this, deletion of GDF3 in inflammasome-activated macrophages improved lipolysis by decreasing MAOA and caspase-1. Furthermore, inhibition of MAOA reversed age-related reduction in adipose tissue NE concentration and restored lipolysis with increased levels of key lipolytic enzymes, adipose triglyceride lipase (ATGL) and hormone sensitive lipase (HSL). Our study reveals that targeting neuro-innate signaling between sympathetic nervous system and macrophages may offer new approaches to mitigate chronic inflammation-induced metabolic impairment and functional decline.
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Affiliation(s)
- Christina D Camell
- Department of Comparative Medicine, Yale School of Medicine, New Haven, Connecticut 06520, USA.,Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Jil Sander
- Genomics and Immunoregulation, LIMES-Institute, University of Bonn, 53115, Bonn, Germany
| | - Olga Spadaro
- Department of Comparative Medicine, Yale School of Medicine, New Haven, Connecticut 06520, USA.,Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Aileen Lee
- Department of Comparative Medicine, Yale School of Medicine, New Haven, Connecticut 06520, USA.,Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Kim Y Nguyen
- Department of Comparative Medicine, Yale School of Medicine, New Haven, Connecticut 06520, USA.,Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Allison Wing
- Department of Molecular, Cellular and Developmental Biology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Emily L Goldberg
- Department of Comparative Medicine, Yale School of Medicine, New Haven, Connecticut 06520, USA.,Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Yun-Hee Youm
- Department of Comparative Medicine, Yale School of Medicine, New Haven, Connecticut 06520, USA.,Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Chester W Brown
- Genetics Division, Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
| | - John Elsworth
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Matthew S Rodeheffer
- Department of Comparative Medicine, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Joachim L Schultze
- Genomics and Immunoregulation, LIMES-Institute, University of Bonn, 53115, Bonn, Germany.,Single Cell Genomics and Epigenomics Unit at the University of Bonn and the German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Vishwa Deep Dixit
- Department of Comparative Medicine, Yale School of Medicine, New Haven, Connecticut 06520, USA.,Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut 06520, USA.,Yale Center for Research on Aging, Yale School of Medicine, New Haven, Connecticut 06520, USA
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34
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Søndergaard E, Espinosa De Ycaza AE, Morgan-Bathke M, Jensen MD. How to Measure Adipose Tissue Insulin Sensitivity. J Clin Endocrinol Metab 2017; 102:1193-1199. [PMID: 28323973 PMCID: PMC5460729 DOI: 10.1210/jc.2017-00047] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 01/23/2017] [Indexed: 02/05/2023]
Abstract
CONTEXT AND OBJECTIVE Adipose tissue insulin resistance may cause hepatic and skeletal muscle insulin resistance by releasing excess free fatty acids (FFAs). Because no consensus exists on how to quantify adipose tissue insulin sensitivity we compared three methods for measuring adipose tissue insulin sensitivity: the single step insulin clamp, the multistep pancreatic clamp, and the adipose tissue insulin resistance index (Adipo-IR). DESIGN AND PARTICIPANTS We studied insulin sensitivity in 25 adults by measuring the insulin concentration resulting in 50% suppression of palmitate flux (IC50) using both a multistep pancreatic clamp and a one-step hyperinsulinemic-euglycemic clamp. Palmitate kinetics were measured using a continuous infusion of [U-13C]palmitate. Adipo-IR was calculated from fasting insulin and fasting FFA concentrations. RESULTS Adipo-IR was reproducible (sample coefficient of variability, 10.0%) and correlated with the IC50 measured by the multistep pancreatic clamp technique (r, 0.86; P < 0.001). Age and physical fitness were significant predictors of the residual variation between Adipo-IR and IC50, with a positive relationship with age (r, 0.47; P = 0.02) and a negative association with VO2 peak (r, -0.46; P = 0.02). Likewise, IC50 measured by the multistep pancreatic clamp technique correlated with IC50 measured using the one-step hyperinsulinemic-euglycemic clamp technique (r, 0.73; P < 0.001). CONCLUSION Adipo-IR and the one-step hyperinsulinemic-euglycemic clamp technique using a palmitate tracer are good predictors of a gold standard measure of adipose tissue insulin sensitivity. However, age and physical fitness systematically affect the predictive values. Although Adipo-IR is suitable for larger population studies, the multistep pancreatic clamp technique is probably needed for mechanistic studies of adipose tissue insulin action.
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Affiliation(s)
- Esben Søndergaard
- Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55905
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, 8000 Aarhus C, Denmark
- The Danish Diabetes Academy, 5000 Odense C, Denmark
| | - Ana Elena Espinosa De Ycaza
- Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55905
- Facultad de Medicina, Universidad de Panamá, Panama City, Republic of Panama
| | - Maria Morgan-Bathke
- Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55905
- Nutrition and Dietetics, Viterbo University, La Crosse, Wisconsin 54601
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Abstract
The demonstration of the presence of metabolically active brown adipose tissue (BAT) in adult humans using positron emission tomography (PET) over the past decade has lead to the rapid development of our knowledge regarding the role of BAT in energy metabolism in animal models and in humans. Although animal models continue to provide highly valuable information regarding the mechanisms regulating BAT development, mass and metabolic functions, these studies led to many assumptions that have been at best only partially verified in humans so far. Combined to some limitations of the current investigation approaches used in humans, this has lead to speculation on the potential role of BAT dysfunction in the development of cardiometabolic disorders and on the potential of BAT metabolic activation to treat these conditions. Here we propose a critical review of the evidence for the implication of BAT in cardiometabolic health.
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Affiliation(s)
- Denis P Blondin
- Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
| | - André C Carpentier
- Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada.
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Shi Y, Shu ZJ, Xue X, Yeh CK, Katz MS, Kamat A. β2-Adrenergic receptor ablation modulates hepatic lipid accumulation and glucose tolerance in aging mice. Exp Gerontol 2016; 78:32-8. [PMID: 26952573 DOI: 10.1016/j.exger.2016.03.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 01/10/2023]
Abstract
Catecholamines acting through β-adrenergic receptors (β(1)-, β(2)-, β(3)-AR subtypes) modulate important biological responses in various tissues. Our previous studies suggest a role for increased hepatic β-AR-mediated signaling during aging as a mediator of hepatic steatosis, liver glucose output, and insulin resistance in rodents. In the current study, we have utilized β(2)-AR knockout (KO) and wildtype (WT) control mice to define further the role of β(2)-AR signaling during aging on lipid and glucose metabolism. Our results demonstrate for the first time that age-related increases in hepatic triglyceride accumulation and body weight are attenuated upon β(2)-AR ablation. Although no differences in plasma triglyceride, non-esterified fatty acids or insulin levels were detected between old WT and KO animals, an age-associated increase in hepatic expression of lipid homeostasis regulator Cidea was significantly reduced in old KO mice. Interestingly, we also observed a shift from reduced glucose tolerance in young adult KO animals to significantly improved glucose tolerance in old KO when compared to age-matched WT mice. These results provide evidence for an important role played by β(2)-ARs in the regulation of lipid and glucose metabolism during aging. The effect of β(2)-AR ablation on caloric intake during aging is currently not known and requires investigation. Future studies are also warranted to delineate the β(2)-AR-mediated mechanisms involved in the control of lipid and glucose homeostasis, especially in the context of a growing aging population.
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Affiliation(s)
- Yun Shi
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, TX 78229, USA; Department of Medicine, University of Texas Health Science Center at San Antonio, TX 78229, USA.
| | - Zhen-Ju Shu
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, TX 78229, USA; Department of Medicine, University of Texas Health Science Center at San Antonio, TX 78229, USA.
| | - Xiaoling Xue
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, TX 78229, USA; Department of Medicine, University of Texas Health Science Center at San Antonio, TX 78229, USA.
| | - Chih-Ko Yeh
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, TX 78229, USA; Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio, TX 78229, USA; Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, TX 78229, USA.
| | - Michael S Katz
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, TX 78229, USA; Department of Medicine, University of Texas Health Science Center at San Antonio, TX 78229, USA; Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio, TX 78229, USA.
| | - Amrita Kamat
- Geriatric Research, Education and Clinical Center, Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, TX 78229, USA; Department of Medicine, University of Texas Health Science Center at San Antonio, TX 78229, USA; Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, TX 78229, USA.
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Vigelsø A, Gram M, Wiuff C, Hansen CN, Prats C, Dela F, Helge JW. Effects of immobilization and aerobic training on proteins related to intramuscular substrate storage and metabolism in young and older men. Eur J Appl Physiol 2015; 116:481-94. [DOI: 10.1007/s00421-015-3302-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 11/16/2015] [Indexed: 12/12/2022]
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Exercise and sleep in aging: emphasis on serotonin. ACTA ACUST UNITED AC 2014; 62:276-83. [PMID: 25104243 DOI: 10.1016/j.patbio.2014.07.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 07/09/2014] [Indexed: 11/23/2022]
Abstract
Reductions in central serotonin activity with aging might be involved in sleep-related disorders in later life. Although the beneficial effects of aerobic exercise on sleep are not new, sleep represents a complex recurring state of unconsciousness involving many lines of transmitters which remains only partly clear despite intense ongoing research. It is known that serotonin released into diencephalon and cerebrum might play a key inhibitory role to help promote sleep, likely through an active inhibition of supraspinal neural networks. Several lines of evidence support the stimulatory effects of exercise on higher serotonergic pathways. Hence, exercise has proved to elicit acute elevations in forebrain serotonin concentrations, an effect that waned upon cessation of exercise. While adequate exercise training might lead to adaptations in higher serotonergic networks (desensitization of forebrain receptors), excessive training has been linked to serious brain serotonergic maladaptations accompanied by insomnia. Dietary supplementation of tryptophan (the only serotonin precursor) is known to stimulate serotonergic activity and promote sleep, whereas acute tryptophan depletion causes deleterious effects on sleep. Regarding sleep-wake regulation, exercise has proved to accelerate resynchronization of the biological clock to new light-dark cycles following imposition of phase shifts in laboratory animals. Noteworthy, the effect of increased serotonergic transmission on wake state appears to be biphasic, i.e. promote wake and thereafter drowsiness. Therefore, it might be possible that acute aerobic exercise would act on sleep by increasing activity of ascending brain serotonergic projections, though additional work is warranted to better understand the implication of serotonin in the exercise-sleep axis.
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Caligiuri SPB, Aukema HM, Ravandi A, Pierce GN. Elevated levels of pro-inflammatory oxylipins in older subjects are normalized by flaxseed consumption. Exp Gerontol 2014; 59:51-7. [PMID: 24747581 DOI: 10.1016/j.exger.2014.04.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 04/08/2014] [Accepted: 04/09/2014] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND AIMS Oxylipins, including eicosanoids, are highly bioactive molecules endogenously produced from polyunsaturated fatty acids. Oxylipins play a key role in chronic disease progression. It is possible, but unknown, if oxylipin concentrations change with the consumption of functional foods or differ with subject age. METHODS Therefore, in a parallel comparator trial, 20 healthy individuals were recruited into a younger (19-28years) or older (45-64years) age group (n=10/group). Participants ingested one muffin/day containing 30g of milled flaxseed (6g alpha-linolenic acid) for 4weeks. Plasma oxylipins were isolated through solid phase extraction, analyzed with HPLC-MS/MS targeted lipidomics, and quantified with the stable isotope dilution method. RESULTS At baseline, the older group exhibited 13 oxylipins ≥2-fold the concentration of the younger group. Specifically, pro-inflammatory oxylipins 5-hydroxyeicosatetraenoic acid, 9,10,13-trihydroxyoctadecenoic acid, and 9,12,13-trihydroxyoctadecenoic acid were significantly greater in the older (1.1±0.23nM, 5.6±0.84nM, and 4.5±0.58nM, respectively) versus the younger group (0.34±0.12nM, 3.5±0.33nM, and 3.0±0.24nM, respectively) (p<0.05). After 4weeks of flaxseed consumption the number of oxylipins that were ≥2-fold higher in the older versus the younger group was reduced to 3. 5-Hydroxyeicosatetraenoic acid, 9,10,13-trihydroxyoctadecenoic acid, and 9,12,13-trihydroxyoctadecenoic acid decreased in the older group to concentrations equivalent to the younger group after flaxseed consumption. CONCLUSION These data suggest a potential role for oxylipins in the aging process and how nutritional interventions like flaxseed can beneficially disrupt these biological changes associated with inflammation and aging.
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Affiliation(s)
- Stephanie P B Caligiuri
- Canadian Centre for Agri-food Research in Health and Medicine (CCARM), 351 Taché Avenue, Winnipeg, Manitoba R2H 2A6, Canada; The Institute of Cardiovascular Sciences, St. Boniface Hospital Research Centre, 351 Taché Avenue, Winnipeg, Manitoba R2H 2A6, Canada; Department of Physiology, 745 Bannatyne Avenue, Winnipeg, MB R3E 0J9, Canada
| | - Harold M Aukema
- Canadian Centre for Agri-food Research in Health and Medicine (CCARM), 351 Taché Avenue, Winnipeg, Manitoba R2H 2A6, Canada; Human Nutritional Sciences, W383 Duff Roblin Building, Winnipeg, MB R3T 2N2, Canada
| | - Amir Ravandi
- The Institute of Cardiovascular Sciences, St. Boniface Hospital Research Centre, 351 Taché Avenue, Winnipeg, Manitoba R2H 2A6, Canada; Internal Medicine, University of Manitoba, 820 Sherbrook Street, Winnipeg, MB R3E 0J9, Canada
| | - Grant N Pierce
- Canadian Centre for Agri-food Research in Health and Medicine (CCARM), 351 Taché Avenue, Winnipeg, Manitoba R2H 2A6, Canada; The Institute of Cardiovascular Sciences, St. Boniface Hospital Research Centre, 351 Taché Avenue, Winnipeg, Manitoba R2H 2A6, Canada; Department of Physiology, 745 Bannatyne Avenue, Winnipeg, MB R3E 0J9, Canada.
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Dobrosielski DA, Barone Gibbs B, Chaudhari S, Ouyang P, Silber HA, Stewart KJ. Effect of exercise on abdominal fat loss in men and women with and without type 2 diabetes. BMJ Open 2013; 3:e003897. [PMID: 24282247 PMCID: PMC3845055 DOI: 10.1136/bmjopen-2013-003897] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVE To examine the effect of exercise on abdominal adipose tissue in adults with and without type 2 diabetes mellitus (T2DM). DESIGN Post hoc analysis of two randomised controlled trials. SETTING Outpatient secondary prevention programme in Baltimore, Maryland, USA. PARTICIPANTS 97 men and women with prehypertension, stage 1 or medically controlled hypertension. 49% of the sample was also diagnosed with T2DM. INTERVENTION All participants completed a 26-week (6.5 months) supervised aerobic and resistance exercise programme following American College of Sports Medicine guidelines. PRIMARY AND SECONDARY OUTCOME MEASURES The main outcomes in this post hoc analysis were total abdominal adipose tissue (TAT), subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) measured by MRI. Secondary outcomes were to determine whether the magnitude of abdominal fat change differed by diabetes status in men and women and to identify the predictors of change in abdominal fat distribution with exercise. RESULTS Overall, participants (mean age 61±6 years; 45% women) significantly improved peak oxygen uptake by 15% (p<0.01) and reduced weight by 2% (p<0.01). No change in SAT was observed after training. The reduction in VAT following exercise was attenuated in participants with T2DM (-3%) compared with participants who were non-T2DM (-18%, p<0.001 for the difference in change). The magnitude of VAT loss was associated with a decrease in body weight (r=0.50, p<0.001). After adjustment for weight change using regression analysis, diabetes status remained an independent predictor of the change in VAT. CONCLUSIONS Although participants with and without T2DM attained an exercise training effect as evidenced by increased fitness, VAT was unchanged in T2DM compared to those without T2DM, suggesting that these individuals may be resistant to this important benefit of exercise. The strategies for reducing cardiovascular disease risk in T2DM may be most effective when they include a weight loss component. CLINICAL TRIALS REGISTRATION Clinicaltrials.gov Registry NCT00212303.
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Affiliation(s)
- Devon A Dobrosielski
- Department of Kinesiology, Towson University, Towson, Maryland, USA
- Division of Cardiology, Department of Medicine, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Bethany Barone Gibbs
- Department of Health and Physical Activity, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Sameer Chaudhari
- Division of Cardiology, Department of Medicine, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Pamela Ouyang
- Division of Cardiology, Department of Medicine, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Harry A Silber
- Division of Cardiology, Department of Medicine, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Kerry J Stewart
- Division of Cardiology, Department of Medicine, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
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Ghosh PM, Shu ZJ, Zhu B, Lu Z, Ikeno Y, Barnes JL, Yeh CK, Zhang BX, Katz MS, Kamat A. Role of β-adrenergic receptors in regulation of hepatic fat accumulation during aging. J Endocrinol 2012; 213:251-61. [PMID: 22457517 PMCID: PMC3539306 DOI: 10.1530/joe-11-0406] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Excessive fat accumulation in liver (hepatic steatosis) predisposes to hepatic functional and structural impairment and overall metabolic risk. Previous studies noted an association between hepatic steatosis and age in humans and rodents. However, the mechanisms leading to age-associated hepatic fat accumulation remain unknown. Earlier work from our group showed that β-adrenergic receptor (β-AR) levels and β-AR-stimulated adenylyl cyclase activity increase in rat liver during aging. Here we investigated whether age-associated increases in β-AR signaling play a role in augmenting hepatic lipid accumulation. We demonstrate an increase in hepatic lipid content during senescence and a significant correlation between hepatic fat content and stimulation of adenylyl cyclase activity by the β-AR agonist isoproterenol in rat liver. Isoproterenol administration to young and old rodents in vivo increased hepatic lipid accumulation. Furthermore, in vitro overexpression of β1- and β2-AR subtypes in hepatocytes from young rodents increased cellular lipid content, whereas inhibition of β-ARs by receptor subtype-specific inhibitors reduced lipid levels in hepatocytes from senescent animals. Isoproterenol-induced hepatic lipid accumulation in vivo was prevented by the β-AR nonselective blocker propranolol, suggesting a novel therapeutic effect of this class of drugs in hepatic steatosis. Acipimox, which inhibits adipose tissue lipolysis, did not alter isoproterenol-mediated hepatic fat accumulation; thus β-AR responsive hepatic lipid accumulation does not appear to be related primarily to altered lipolysis. These findings suggest that augmented hepatic β-AR signaling during aging may increase lipid accumulation in liver and advocate a possible role for β-adrenergic blockers in preventing or retarding the development of hepatic steatosis.
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MESH Headings
- Adenylyl Cyclases/metabolism
- Adrenergic beta-Agonists/pharmacology
- Adrenergic beta-Antagonists/pharmacology
- Aging
- Animals
- Cells, Cultured
- Enzyme Activation/drug effects
- Fats/metabolism
- Hepatocytes/drug effects
- Hepatocytes/metabolism
- Imidazoles/pharmacology
- Isoproterenol/pharmacology
- Lipids/analysis
- Liver/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Propanolamines/pharmacology
- Propranolol/pharmacology
- Rats
- Rats, Inbred F344
- Receptors, Adrenergic, beta/genetics
- Receptors, Adrenergic, beta/metabolism
- Receptors, Adrenergic, beta-1/genetics
- Receptors, Adrenergic, beta-1/metabolism
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Signal Transduction/drug effects
- Time Factors
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Affiliation(s)
- Paramita M Ghosh
- Geriatric Research, Education and Clinical Center (182), Audie L. Murphy Division, South Texas Veterans Health Care System, 7400 Merton Minter Boulevard, San Antonio, Texas 78229, USA
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Wohlers LM, Jackson KC, Spangenburg EE. Lipolytic signaling in response to acute exercise is altered in female mice following ovariectomy. J Cell Biochem 2012; 112:3675-84. [PMID: 21815195 DOI: 10.1002/jcb.23302] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Impaired ovarian function alters lipid metabolism, ultimately resulting in increased visceral fat mass. Currently, we have a poor understanding of alterations in signaling events regulating lipolysis after ovarian function declines. The purpose of this study was to determine if cellular mechanisms regulating lipolysis are altered in mice after ovariectomy (OVX) and if OVX mice exhibit impaired lipolytic signaling when stimulated by acute exercise. SHAM and OVX mice were divided into two groups: control (SHAM cont; OVX cont) or acute treadmill exercise (SHAM ex; OVX ex). The omental/mesenteric (O/M) fat mass of all OVX mice was significantly greater than the SHAM mice. Serum glycerol and blood glucose levels were significantly elevated in OVX cont compared to SHAM cont. Treadmill exercise increased serum glycerol levels only in SHAM mice, with no exercise-induced change detected in OVX mice. NEFA levels were significantly elevated by acute exercise in the SHAM and OVX groups. In O/M fat from both OVX groups there were significant increases in cytosolic ATGL and PLIN2 in the fat cake fraction with concurrent reductions in PLIN1 in the fat cake compared to SHAM. Further, exercise induced significant increases in HSL Ser660 phosphorylation in SHAM mice, but not OVX mice. This suggests that reduced ovarian function has significant effects on critical lipolytic cell signaling mechanisms in O/M adipose tissue.
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Affiliation(s)
- Lindsay M Wohlers
- Department of Kinesiology, University of Maryland, School of Public Health, College Park, Maryland 21045, USA
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Zhang Y. Utility of transplantation in studying adipocyte biogenesis and function. Mol Cell Endocrinol 2010; 318:15-23. [PMID: 19733623 PMCID: PMC2826534 DOI: 10.1016/j.mce.2009.08.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 08/27/2009] [Accepted: 08/30/2009] [Indexed: 10/20/2022]
Abstract
Adipose tissue plays important roles in the regulation of energy homeostasis and metabolism. Two features distinguish adipose tissue from other organs--the ability to greatly expand its mass, via increases in cell size and/or number, and the wide anatomical distribution. While adipose tissue function is greatly affected by adipocyte size and anatomic location, regulations of adipocyte size, number, and body fat distribution are poorly understood. Transplantation of either mature adipose tissue or adipocyte progenitor cells has been used in studying adipocyte function and biogenesis. In this review, we will attempt to summarize methodological considerations for transplantation, including selections of donor material, transplantation site and the length of transplantation study, as well as effects of these factors and vascularization and innervation on the function of transplants. Specific studies are also reviewed to illustrate the utility of adipose tissue transplants in studying adipose tissue function and biogenesis. The focus is on studies in three areas: (1) use of transplants in demonstrating adipose tissue function, such as effects of adipose tissue transplants on metabolism and energy homeostasis of the recipient animals and depot-specific differences in adipose tissue function; (2) use of transplantation to dissect direct or cell-autonomous from indirect or non-cell-autonomous effects of leptin signaling and sex on adipocyte size; (3) use of transplantation in the identification of adipocyte progenitor cells and lineage analysis. Finally, future applications of transplantation in studying depot-specific adipocyte biogenesis, and genetic and hormonal effects of sex and age on adipocyte biogenesis and function are discussed.
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Affiliation(s)
- Yiying Zhang
- Division of Molecular Genetics, Department of Pediatrics, Columbia University, New York, NY 10032, USA.
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Goree LLT, Darnell BE, Oster RA, Brown MA, Gower BA. Associations of free fatty acids with insulin secretion and action among African-American and European-American girls and women. Obesity (Silver Spring) 2010; 18:247-53. [PMID: 19680231 PMCID: PMC2814008 DOI: 10.1038/oby.2009.248] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ethnic differences in insulin secretion and action between African Americans (AAs) and European Americans (EAs) may influence mobilization of free fatty acids (FFAs). We tested the hypotheses that FFA concentrations would be associated with measures of insulin secretion and action before and during a glucose challenge test. Subjects were 48 prepubertal girls, 60 premenopausal women, and 46 postmenopausal women. Fasting insulin (insulin(0)), the acute insulin response to glucose (AIR(g)), the insulin sensitivity index (S(I)), basal and nadir FFA (FFA(0), FFA(nadir)), and nadir time (TIME(nadir)) were determined during an intravenous glucose tolerance test (IVGTT). Stepwise multiple linear regression (MLR) analysis was conducted to identify associations of FFA(0), FFA(nadir), and TIME(nadir) with ethnicity, age group, insulin measures, indexes of body composition from dual-energy X-ray absorptiometry, and measures of fat distribution from computed tomography scan. In this population, insulin(0) and AIR(g) were higher among AAs vs. EAs, whereas S(I) was lower, independent of age group. MLR analyses indicated that FFA(0) was best predicted by lean tissue mass (LTM), leg fat mass, ethnicity (lower in AAs), S(I), and insulin(0). FFA(nadir) was best predicted by FFA(0), age group, and intra-abdominal adipose tissue (IAAT). TIME(nadir) was best predicted by leg fat mass, AIR(g), and S(I). In conclusion, indexes of insulin secretion and action were associated with FFA dynamics in healthy girls and women. Lower FFA(0) among AAs was independent of insulin(0) and S(I). Whether lower FFA(0) is associated with substrate oxidation or risk for obesity remains to be determined.
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Affiliation(s)
- Laura Lee T Goree
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama, USA.
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Mittendorfer B, Klein S. Physiological factors that regulate the use of endogenous fat and carbohydrate fuels during endurance exercise. Nutr Res Rev 2009; 16:97-108. [DOI: 10.1079/nrr200357] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Wang S, Soni KG, Semache M, Casavant S, Fortier M, Pan L, Mitchell GA. Lipolysis and the integrated physiology of lipid energy metabolism. Mol Genet Metab 2008; 95:117-26. [PMID: 18762440 DOI: 10.1016/j.ymgme.2008.06.012] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 06/30/2008] [Accepted: 06/30/2008] [Indexed: 11/18/2022]
Abstract
Fat cell lipolysis, the cleavage of triglycerides and release of fatty acids and glycerol, evolved to enable survival during prolonged food deprivation but is paradoxically increased in obesity, in which a surfeit of all energy metabolites is found. Essential, previously-unsuspected components have been discovered in the lipolytic machinery, at the protective interface of the lipid droplet surface and in the signaling pathways that control lipolysis. At least two adipocyte lipases are important for controlling lipolysis, hormone-sensitive lipase (HSL) and adipocyte triglyceride lipase (ATGL). Perilipin (PLIN) and possibly other proteins of the lipid droplet surface are master regulators of lipolysis, protecting or exposing the triglyceride core of the droplet to lipases. The prototypes for hormonal lipolytic control are beta adrenergic stimulation and suppression by insulin, both of which affect cyclic AMP levels and hence the protein kinase A-mediated phosphorylation of HSL and PLIN. Newly-recognized mediators of lipolysis include atrial natriuretic peptide, cyclic GMP, the ketone body 3-hydroxybutyrate, AMP kinase and mitogen-activated kinases. Lipolysis must be interpreted in its physiological context since similar rates of basal or stimulated lipolysis occur under different conditions and by different mechanisms. Age, sex, anatomical site, genotype and species differences are each important variables. Manipulation of lipolysis has therapeutic potential in several inborn errors and in the metabolic syndrome that frequently complicates obesity.
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Affiliation(s)
- Shupei Wang
- Division of Medical Genetics, CHU Sainte-Justine, Montréal, Quebec, Canada
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Kodama T, Ashitani JI, Matsumoto N, Kangawa K, Nakazato M. Ghrelin treatment suppresses neutrophil-dominant inflammation in airways of patients with chronic respiratory infection. Pulm Pharmacol Ther 2008; 21:774-9. [PMID: 18571961 DOI: 10.1016/j.pupt.2008.05.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 05/02/2008] [Accepted: 05/12/2008] [Indexed: 02/06/2023]
Abstract
BACKGROUND Persistent neutrophil influx into the airways is a characteristic of chronic respiratory infection and contributes to the deterioration of pulmonary function. Ghrelin is a novel growth hormone (GH)-releasing peptide with potential anti-inflammatory activities. The present study investigated whether or not ghrelin can reduce neutrophil-dominant inflammation in airways of patients with chronic respiratory infection. POPULATIONS AND METHODS Synthesized ghrelin was administered intravenously for 3 weeks to 7 cachectic patients with chronic respiratory infection to confirm ghrelin's effects on airway inflammation and nutrition state. Neutrophils, neutrophil products and inflammatory cytokines in sputum were used as markers of airway inflammation. Changes in serum protein levels were also evaluated along with plasma catecholamine levels. Exercise tolerance was assessed by measuring 6-min walking distance before and after 3 weeks of ghrelin treatment. RESULTS Three-week ghrelin administration decreased neutrophil density and inflammatory cytokine levels in sputum, reduced plasma norepinephrine level, and increased body weight, serum protein level, and 6-min walking distance. CONCLUSIONS Ghrelin administration suppressed airway inflammation by decreasing neutrophil accumulation in lungs and increased body weight. These findings may contribute to the development of supportive therapies for patients with refractory chronic respiratory infection.
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Affiliation(s)
- Tsuyoshi Kodama
- Third Department of Internal Medicine, Miyazaki University School of Medicine, Kihara 5200, Miyazaki 889-1692, Japan
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Bassami M, Ahmadizad S, Doran D, MacLaren DPM. Effects of exercise intensity and duration on fat metabolism in trained and untrained older males. Eur J Appl Physiol 2007; 101:525-32. [PMID: 17724610 DOI: 10.1007/s00421-007-0523-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2007] [Indexed: 11/29/2022]
Abstract
Advancing age is associated with changes in fat and carbohydrate (CHO) metabolism, which is considered a risk factor for cardiovascular disease and diabetes. The effects of exercise intensity and duration on fat and CHO metabolism in elderly male subjects were investigated in the present study. Seven trained (63.7+/-4.7 years) and six untrained (63.5+/-4.5 years) healthy males performed three 30 min trials on a cycle ergometer at 50, 60 and 70% VO2max and two other trials at 60 and 70% VO2max in which the total energy expenditure was equal to that for 30 min at 50% VO2max Respiratory measures were undertaken throughout the exercise and blood samples taken before and immediately after each trial. Statistical analyses revealed a significant effect of exercise intensity on fat oxidation when the exercise durations were equated as well as when the energy expenditure was held constant for the three trials, though no training effect was noted. Total carbohydrate oxidation increased significantly with exercise intensity (P<0.05) and with training. Significantly higher levels of non-esterified free fatty acid (NEFA) and glycerol were observed for trained compared with untrained though not for B-hydroxybutyrate (3-OH) or insulin. No differences in NEFA, glycerol, 3-OH were evident for increases in exercise intensity. Carbohydrate and fat oxidation are significantly affected by exercise intensity in elderly males, although only CHO oxidation is influenced by training. Furthermore, training-induced increases in the availability of NEFA and glycerol are not associated with an increase in fat oxidation, rather an increase in CHO oxidation.
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Affiliation(s)
- Minoo Bassami
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Henry Cotton Campus, 15-21 Webster Street, Liverpool, L3 2ET, UK
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Abstract
1. The aim of the present review is to outline: (i) the association between sleep and metabolism; (ii) how sleep duration influences the development of disease; and (iii) how sex differences, ageing and obesity may potentially influence the relationship between sleep, metabolic control and subsequent disease. 2. Sleep is associated with a number of endocrine changes, including a change in insulin action in healthy young individuals. Sleep duration shows a prospective U-shaped relationship with all-cause mortality, cardiovascular disease and Type 2 diabetes. 3. Chronic sleep restriction is becoming more common. Experimental sleep restriction impedes daytime glucose control and increases appetite. 4. The sex hormones oestrogen and testosterone influence sleep duration and quality and may account for sex differences in the prevalence of sleep-related disorders. 5. Ageing is associated with a decreased sleep duration, decreased muscle mass and impaired insulin action. 6. Obesity impairs insulin action and is associated with the incidence and severity of obstructive sleep apnoea. 7. Sleep plays an integral role in metabolic control. Consequently, insufficient sleep may represent a modifiable risk factor for the development of Type 2 diabetes. The challenge ahead is to identify how sex differences, ageing and obesity could potentially influence the relationship between sleep and metabolism.
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Affiliation(s)
- Michael I Trenell
- Sleep and Circadian Research Group, Woolcock Institute of Medical Research, Sydney, NSW, Australia
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