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Zhao Y, Yue R. Aging adipose tissue, insulin resistance, and type 2 diabetes. Biogerontology 2024; 25:53-69. [PMID: 37725294 DOI: 10.1007/s10522-023-10067-6] [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: 06/18/2023] [Accepted: 08/28/2023] [Indexed: 09/21/2023]
Abstract
With the increase of population aging, the prevalence of type 2 diabetes (T2D) is also rising. Aging affects the tissues and organs of the whole body, which is the result of various physiological and pathological processes. Adipose tissue has a high degree of plasticity and changes with aging. Aging changes the distribution of adipose tissue, affects adipogenesis, browning characteristics, inflammatory status and adipokine secretion, and increases lipotoxicity. These age-dependent changes in adipose tissue are an important cause of insulin resistance and T2D. Understanding adipose tissue changes can help promote healthy aging process. This review summarizes changes in adipose tissue ascribable to aging, with a focus on the role of aging adipose tissue in insulin resistance and T2D.
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Affiliation(s)
- Yixuan Zhao
- Hospital of Chengdu University of Traditional Chinese Medicine, NO. 39 Shi-Er-Qiao Road, Chengdu, 610072, Sichuan Province, People's Republic of China
| | - Rensong Yue
- Hospital of Chengdu University of Traditional Chinese Medicine, NO. 39 Shi-Er-Qiao Road, Chengdu, 610072, Sichuan Province, People's Republic of China.
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2
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Bogard G, Barthelemy J, Hantute-Ghesquier A, Sencio V, Brito-Rodrigues P, Séron K, Robil C, Flourens A, Pinet F, Eberlé D, Trottein F, Duterque-Coquillaud M, Wolowczuk I. SARS-CoV-2 infection induces persistent adipose tissue damage in aged golden Syrian hamsters. Cell Death Dis 2023; 14:75. [PMID: 36725844 PMCID: PMC9891765 DOI: 10.1038/s41419-023-05574-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 01/04/2023] [Accepted: 01/09/2023] [Indexed: 02/03/2023]
Abstract
Coronavirus disease 2019 (COVID-19, caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2)) is primarily a respiratory illness. However, various extrapulmonary manifestations have been reported in patients with severe forms of COVID-19. Notably, SARS-CoV-2 was shown to directly trigger white adipose tissue (WAT) dysfunction, which in turn drives insulin resistance, dyslipidemia, and other adverse outcomes in patients with COVID-19. Although advanced age is the greatest risk factor for COVID-19 severity, published data on the impact of SARS-CoV-2 infection on WAT in aged individuals are scarce. Here, we characterized the response of subcutaneous and visceral WAT depots to SARS-CoV-2 infection in young adult and aged golden hamsters. In both age groups, infection was associated with a decrease in adipocyte size in the two WAT depots; this effect was partly due to changes in tissue's lipid metabolism and persisted for longer in aged hamsters than in young-adult hamsters. In contrast, only the subcutaneous WAT depot contained crown-like structures (CLSs) in which dead adipocytes were surrounded by SARS-CoV-2-infected macrophages, some of them forming syncytial multinucleated cells. Importantly, older age predisposed to a unique manifestation of viral disease in the subcutaneous WAT depot during SARS-CoV-2 infection; the persistence of very large CLSs was indicative of an age-associated defect in the clearance of dead adipocytes by macrophages. Moreover, we uncovered age-related differences in plasma lipid profiles during SARS-CoV-2 infection. These data suggest that the WAT's abnormal response to SARS-CoV-2 infection may contribute to the greater severity of COVID-19 observed in elderly patients.
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Affiliation(s)
- Gemma Bogard
- Univ. Lille, Institut National de la Santé et de la Recherche Médicale (Inserm), Centre National de la Recherche Scientifique (CNRS), Centre Hospitalier Universitaire de Lille (CHU Lille), Institut Pasteur de Lille, U1019-UMR9017-Center for Infection and Immunity of Lille (CIIL), F-59000, Lille, France
| | - Johanna Barthelemy
- Univ. Lille, Institut National de la Santé et de la Recherche Médicale (Inserm), Centre National de la Recherche Scientifique (CNRS), Centre Hospitalier Universitaire de Lille (CHU Lille), Institut Pasteur de Lille, U1019-UMR9017-Center for Infection and Immunity of Lille (CIIL), F-59000, Lille, France
| | - Aline Hantute-Ghesquier
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000, Lille, France
| | - Valentin Sencio
- Univ. Lille, Institut National de la Santé et de la Recherche Médicale (Inserm), Centre National de la Recherche Scientifique (CNRS), Centre Hospitalier Universitaire de Lille (CHU Lille), Institut Pasteur de Lille, U1019-UMR9017-Center for Infection and Immunity of Lille (CIIL), F-59000, Lille, France
| | - Patricia Brito-Rodrigues
- Univ. Lille, Institut National de la Santé et de la Recherche Médicale (Inserm), Centre National de la Recherche Scientifique (CNRS), Centre Hospitalier Universitaire de Lille (CHU Lille), Institut Pasteur de Lille, U1019-UMR9017-Center for Infection and Immunity of Lille (CIIL), F-59000, Lille, France
| | - Karin Séron
- Univ. Lille, Institut National de la Santé et de la Recherche Médicale (Inserm), Centre National de la Recherche Scientifique (CNRS), Centre Hospitalier Universitaire de Lille (CHU Lille), Institut Pasteur de Lille, U1019-UMR9017-Center for Infection and Immunity of Lille (CIIL), F-59000, Lille, France
| | - Cyril Robil
- Univ. Lille, Institut National de la Santé et de la Recherche Médicale (Inserm), Centre National de la Recherche Scientifique (CNRS), Centre Hospitalier Universitaire de Lille (CHU Lille), Institut Pasteur de Lille, U1019-UMR9017-Center for Infection and Immunity of Lille (CIIL), F-59000, Lille, France
| | - Anne Flourens
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000, Lille, France
| | - Florence Pinet
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE-Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, F-59000, Lille, France
| | - Delphine Eberlé
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F-59000, Lille, France
| | - François Trottein
- Univ. Lille, Institut National de la Santé et de la Recherche Médicale (Inserm), Centre National de la Recherche Scientifique (CNRS), Centre Hospitalier Universitaire de Lille (CHU Lille), Institut Pasteur de Lille, U1019-UMR9017-Center for Infection and Immunity of Lille (CIIL), F-59000, Lille, France
| | - Martine Duterque-Coquillaud
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000, Lille, France
| | - Isabelle Wolowczuk
- Univ. Lille, Institut National de la Santé et de la Recherche Médicale (Inserm), Centre National de la Recherche Scientifique (CNRS), Centre Hospitalier Universitaire de Lille (CHU Lille), Institut Pasteur de Lille, U1019-UMR9017-Center for Infection and Immunity of Lille (CIIL), F-59000, Lille, France.
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3
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Ou MY, Zhang H, Tan PC, Zhou SB, Li QF. Adipose tissue aging: mechanisms and therapeutic implications. Cell Death Dis 2022; 13:300. [PMID: 35379822 PMCID: PMC8980023 DOI: 10.1038/s41419-022-04752-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/03/2022] [Accepted: 03/18/2022] [Indexed: 01/10/2023]
Abstract
Adipose tissue, which is the crucial energy reservoir and endocrine organ for the maintenance of systemic glucose, lipid, and energy homeostasis, undergoes significant changes during aging. These changes cause physiological declines and age-related disease in the elderly population. Here, we review the age-related changes in adipose tissue at multiple levels and highlight the underlying mechanisms regulating the aging process. We also discuss the pathogenic pathways of age-related fat dysfunctions and their systemic negative consequences, such as dyslipidemia, chronic general inflammation, insulin resistance, and type 2 diabetes (T2D). Age-related changes in adipose tissue involve redistribution of deposits and composition, in parallel with the functional decline of adipocyte progenitors and accumulation of senescent cells. Multiple pathogenic pathways induce defective adipogenesis, inflammation, aberrant adipocytokine production, and insulin resistance, leading to adipose tissue dysfunction. Changes in gene expression and extracellular signaling molecules regulate the aging process of adipose tissue through various pathways. In addition, adipose tissue aging impacts other organs that are infiltrated by lipids, which leads to systemic inflammation, metabolic system disruption, and aging process acceleration. Moreover, studies have indicated that adipose aging is an early onset event in aging and a potential target to extend lifespan. Together, we suggest that adipose tissue plays a key role in the aging process and is a therapeutic target for the treatment of age-related disease, which deserves further study to advance relevant knowledge.
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Affiliation(s)
- Min-Yi Ou
- Department of Plastic & Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China
| | - Hao Zhang
- Department of Plastic & Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China
| | - Poh-Ching Tan
- Department of Plastic & Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China
| | - Shuang-Bai Zhou
- Department of Plastic & Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China.
| | - Qing-Feng Li
- Department of Plastic & Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China.
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Thakkar N, Shin YB, Sung HK. Nutritional Regulation of Mammary Tumor Microenvironment. Front Cell Dev Biol 2022; 10:803280. [PMID: 35186923 PMCID: PMC8847692 DOI: 10.3389/fcell.2022.803280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 01/12/2022] [Indexed: 12/12/2022] Open
Abstract
The mammary gland is a heterogeneous organ comprising of immune cells, surrounding adipose stromal cells, vascular cells, mammary epithelial, and cancer stem cells. In response to nutritional stimuli, dynamic interactions amongst these cell populations can be modulated, consequently leading to an alteration of the glandular function, physiology, and ultimately disease pathogenesis. For example, obesity, a chronic over-nutritional condition, is known to disrupt homeostasis within the mammary gland and increase risk of breast cancer development. In contrast, emerging evidence has demonstrated that fasting or caloric restriction can negatively impact mammary tumorigenesis. However, how fasting induces phenotypic and functional population differences in the mammary microenvironment is not well understood. In this review, we will provide a detailed overview on the effect of nutritional conditions (i.e., overnutrition or fasting) on the mammary gland microenvironment and its impact on mammary tumor progression.
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Affiliation(s)
- Nikita Thakkar
- Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Ye Bin Shin
- Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Hoon-Ki Sung
- Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- *Correspondence: Hoon-Ki Sung,
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AlSudais H, Wiper-Bergeron N. From quiescence to repair: C/EBPβ as a regulator of muscle stem cell function in health and disease. FEBS J 2021; 289:6518-6530. [PMID: 34854237 DOI: 10.1111/febs.16307] [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: 08/13/2021] [Revised: 10/21/2021] [Accepted: 11/30/2021] [Indexed: 11/26/2022]
Abstract
CCAAT/Enhancer Binding protein beta (C/EBPβ) is a transcriptional regulator involved in numerous physiological processes. Herein, we describe a role for C/EBPβ as a regulator of skeletal muscle stem cell function. In particular, C/EBPβ is expressed in muscle stem cells in healthy muscle where it inhibits myogenic differentiation. Downregulation of C/EBPβ expression at the protein and transcriptional level allows for differentiation. Persistence of C/EBPβ promotes stem cell self-renewal and C/EBPβ expression is required for mitotic quiescence in this cell population. As a critical regulator of skeletal muscle homeostasis, C/EBPβ expression is stimulated in pathological conditions such as cancer cachexia, which perturbs muscle regeneration and promotes myofiber atrophy in the context of systemic inflammation. C/EBPβ is also an important regulator of cytokine expression and immune response genes, a mechanism by which it can influence muscle stem cell function. In this viewpoint, we describe a role for C/EBPβ in muscle stem cells and propose a functional intersection between C/EBPβ and NF-kB action in the regulation of cancer cachexia.
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Affiliation(s)
- Hamood AlSudais
- Graduate Program in Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Canada.,Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Saudi Arabia
| | - Nadine Wiper-Bergeron
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Canada
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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: 30] [Impact Index Per Article: 10.0] [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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Sadie-Van Gijsen H. Is Adipose Tissue the Fountain of Youth? The Impact of Adipose Stem Cell Aging on Metabolic Homeostasis, Longevity, and Cell-Based Therapies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1286:225-250. [PMID: 33725357 DOI: 10.1007/978-3-030-55035-6_16] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Aging is driven by four interlinked processes: (1) low-grade sterile inflammation; (2) macromolecular and organelle dysfunction, including DNA damage, telomere erosion, and mitochondrial dysfunction; (3) stem cell dysfunction; and (4) an accumulation of senescent cells in tissues. Adipose tissue is not immune to the effects of time, and all four of these processes contribute to a decline of adipose tissue function with advanced age. This decline is associated with an increase in metabolic disorders. Conversely, optimally functioning adipose tissue generates signals that promote longevity. As tissue-resident progenitor cells that actively participate in adipose tissue homeostasis and dysregulation, adipose stem cells (ASCs) have emerged as a key feature in the relationship between age and adipose tissue function. This review will give a mechanistic overview of the myriad ways in which age affects ASC function and, conversely, how ASC function contribute to healthspan and lifespan. A central mediator in this relationship is the degree of resilience of ASCs to maintain stemness into advanced age and the consequent preservation of adipose tissue function, in particular subcutaneous fat. The last sections of this review will discuss therapeutic options that target senescent ASCs to extend healthspan and lifespan, as well as ASC-based therapies that can be used to treat age-related pathologies, and collectively, these therapeutic applications may transform the way we age.
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Affiliation(s)
- Hanél Sadie-Van Gijsen
- Centre for Cardiometabolic Research in Africa (CARMA), Division of Medical Physiology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg Campus, Parow, South Africa.
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Loss of Malat1 does not modify age- or diet-induced adipose tissue accretion and insulin resistance in mice. PLoS One 2018; 13:e0196603. [PMID: 29746487 PMCID: PMC5944987 DOI: 10.1371/journal.pone.0196603] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 04/16/2018] [Indexed: 12/18/2022] Open
Abstract
Several studies have suggested that signals emerging from white adipose tissue can contribute to the control of longevity. In turn, aging is associated with perturbed regulation and partitioning of fat depots and insulin resistance. However, the exact mechanisms involved in these relationships remain undetermined. Using RAP-PCR on adipose tissue of young and old male mice coupled with qPCR validation, we have uncovered the long non-coding RNA Malat1 as a gene robustly downregulated in visceral white adipose tissue (vWAT) during normal aging in male mice and men. Reductions in Malat1 expression in subcutaneous WAT (scWAT) were also observed in genetic (ob and db) as well as diet-induced models of obesity. Based on these findings, Malat1+/+ and Malat1-/- mouse littermates were thus probed to detect whether loss of Malat1 would impact age or diet-induced gain in fat mass and development of glucose intolerance. Contrary to this hypothesis, male and female Malat1-deficient mice gained as much weight, and developed insulin resistance to a similar extent as their Malat1+/+ littermates when studied up to eight months old on regular chow or a high-fat, high-sucrose diet. Moreover, we observed no marked difference in oxygen consumption, food intake, or lipid profiles between Malat1+/+ and Malat1-/- mice. Therefore, we conclude that the overall metabolic impact of the absence of Malat1 on adipose tissue accretion and glucose intolerance is either physiologically not relevant upon aging and obesity, or that it is masked by as yet unknown compensatory mechanisms.
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Nutter CA, Kuyumcu-Martinez MN. Emerging roles of RNA-binding proteins in diabetes and their therapeutic potential in diabetic complications. WILEY INTERDISCIPLINARY REVIEWS-RNA 2017; 9. [PMID: 29280295 DOI: 10.1002/wrna.1459] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/19/2017] [Accepted: 11/05/2017] [Indexed: 12/11/2022]
Abstract
Diabetes is a debilitating health care problem affecting 422 million people around the world. Diabetic patients suffer from multisystemic complications that can cause mortality and morbidity. Recent advancements in high-throughput next-generation RNA-sequencing and computational algorithms led to the discovery of aberrant posttranscriptional gene regulatory programs in diabetes. However, very little is known about how these regulatory programs are mis-regulated in diabetes. RNA-binding proteins (RBPs) are important regulators of posttranscriptional RNA networks, which are also dysregulated in diabetes. Human genetic studies provide new evidence that polymorphisms and mutations in RBPs are linked to diabetes. Therefore, we will discuss the emerging roles of RBPs in abnormal posttranscriptional gene expression in diabetes. Questions that will be addressed are: Which posttranscriptional mechanisms are disrupted in diabetes? Which RBPs are responsible for such changes under diabetic conditions? How are RBPs altered in diabetes? How does dysregulation of RBPs contribute to diabetes? Can we target RBPs using RNA-based methods to restore gene expression profiles in diabetic patients? Studying the evolving roles of RBPs in diabetes is critical not only for a comprehensive understanding of diabetes pathogenesis but also to design RNA-based therapeutic approaches for diabetic complications. WIREs RNA 2018, 9:e1459. doi: 10.1002/wrna.1459 This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > Splicing Regulation/Alternative Splicing Translation > Translation Regulation.
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Affiliation(s)
- Curtis A Nutter
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas
| | - Muge N Kuyumcu-Martinez
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas.,Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas.,Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas
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Stout MB, Justice JN, Nicklas BJ, Kirkland JL. Physiological Aging: Links Among Adipose Tissue Dysfunction, Diabetes, and Frailty. Physiology (Bethesda) 2017; 32:9-19. [PMID: 27927801 DOI: 10.1152/physiol.00012.2016] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Advancing age is associated with progressive declines in physiological function that lead to overt chronic disease, frailty, and eventual mortality. Importantly, age-related physiological changes occur in cellularity, insulin-responsiveness, secretory profiles, and inflammatory status of adipose tissue, leading to adipose tissue dysfunction. Although the mechanisms underlying adipose tissue dysfunction are multifactorial, the consequences result in secretion of proinflammatory cytokines and chemokines, immune cell infiltration, an accumulation of senescent cells, and an increase in senescence-associated secretory phenotype (SASP). These processes synergistically promote chronic sterile inflammation, insulin resistance, and lipid redistribution away from subcutaneous adipose tissue. Without intervention, these effects contribute to age-related systemic metabolic dysfunction, physical limitations, and frailty. Thus adipose tissue dysfunction may be a fundamental contributor to the elevated risk of chronic disease, disability, and adverse health outcomes with advancing age.
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Affiliation(s)
- Michael B Stout
- Department of Nutritional Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.,Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Jamie N Justice
- Department of Internal Medicine-Geriatrics, Sticht Center on Aging, Wake Forest School of Medicine, Winston-Salem, North Carolina; and
| | - Barbara J Nicklas
- Department of Internal Medicine-Geriatrics, Sticht Center on Aging, Wake Forest School of Medicine, Winston-Salem, North Carolina; and
| | - James L Kirkland
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, Minnesota
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Prostek A, Gajewska M, Bałasińska B. The influence of eicosapentaenoic acid and docosahexaenoic acid on expression of genes connected with metabolism and secretory functions of ageing 3T3-L1 adipocytes. Prostaglandins Other Lipid Mediat 2016; 125:48-56. [DOI: 10.1016/j.prostaglandins.2016.04.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 11/29/2022]
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12
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Cathelicidin suppresses lipid accumulation and hepatic steatosis by inhibition of the CD36 receptor. Int J Obes (Lond) 2016; 40:1424-34. [PMID: 27163748 PMCID: PMC5014693 DOI: 10.1038/ijo.2016.90] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 04/27/2016] [Accepted: 04/30/2016] [Indexed: 01/29/2023]
Abstract
BACKGROUND AND OBJECTIVES Obesity is a global epidemic which increases the risk of the metabolic syndrome. Cathelicidin (LL-37 and mCRAMP) is an antimicrobial peptide with an unknown role in obesity. We hypothesize that cathelicidin expression correlates with obesity and modulates fat mass and hepatic steatosis. MATERIALS AND METHODS Male C57BL/6 J mice were fed a high-fat diet. Streptozotocin was injected into mice to induce diabetes. Experimental groups were injected with cathelicidin and CD36 overexpressing lentiviruses. Human mesenteric fat adipocytes, mouse 3T3-L1 differentiated adipocytes and human HepG2 hepatocytes were used in the in vitro experiments. Cathelicidin levels in non-diabetic, prediabetic and type II diabetic patients were measured by enzyme-linked immunosorbent assay. RESULTS Lentiviral cathelicidin overexpression reduced hepatic steatosis and decreased the fat mass of high-fat diet-treated diabetic mice. Cathelicidin overexpression reduced mesenteric fat and hepatic fatty acid translocase (CD36) expression that was reversed by lentiviral CD36 overexpression. Exposure of adipocytes and hepatocytes to cathelicidin significantly inhibited CD36 expression and reduced lipid accumulation. Serum cathelicidin protein levels were significantly increased in non-diabetic and prediabetic patients with obesity, compared with non-diabetic patients with normal body mass index (BMI) values. Prediabetic patients had lower serum cathelicidin protein levels than non-diabetic subjects. CONCLUSIONS Cathelicidin inhibits the CD36 fat receptor and lipid accumulation in adipocytes and hepatocytes, leading to a reduction of fat mass and hepatic steatosis in vivo. Circulating cathelicidin levels are associated with increased BMI. Our results demonstrate that cathelicidin modulates the development of obesity.
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Xu M, Palmer AK, Ding H, Weivoda MM, Pirtskhalava T, White TA, Sepe A, Johnson KO, Stout MB, Giorgadze N, Jensen MD, LeBrasseur NK, Tchkonia T, Kirkland JL. Targeting senescent cells enhances adipogenesis and metabolic function in old age. eLife 2015; 4:e12997. [PMID: 26687007 PMCID: PMC4758946 DOI: 10.7554/elife.12997] [Citation(s) in RCA: 394] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 12/18/2015] [Indexed: 12/22/2022] Open
Abstract
Senescent cells accumulate in fat with aging. We previously found genetic clearance of senescent cells from progeroid INK-ATTAC mice prevents lipodystrophy. Here we show that primary human senescent fat progenitors secrete activin A and directly inhibit adipogenesis in non-senescent progenitors. Blocking activin A partially restored lipid accumulation and expression of key adipogenic markers in differentiating progenitors exposed to senescent cells. Mouse fat tissue activin A increased with aging. Clearing senescent cells from 18-month-old naturally-aged INK-ATTAC mice reduced circulating activin A, blunted fat loss, and enhanced adipogenic transcription factor expression within 3 weeks. JAK inhibitor suppressed senescent cell activin A production and blunted senescent cell-mediated inhibition of adipogenesis. Eight weeks-treatment with ruxolitinib, an FDA-approved JAK1/2 inhibitor, reduced circulating activin A, preserved fat mass, reduced lipotoxicity, and increased insulin sensitivity in 22-month-old mice. Our study indicates targeting senescent cells or their products may alleviate age-related dysfunction of progenitors, adipose tissue, and metabolism. DOI:http://dx.doi.org/10.7554/eLife.12997.001 The likelihood of developing metabolic diseases such as diabetes increases with age. This is, in part, because the cells within fat and other tissues become less sensitive to the hormone insulin as people and other animals get older. Also, the stem cells that give rise to new, insulin-responsive fat cells become dysfunctional with increasing age. This is related to the accumulation of “senescent” cells, which, unlike normal fat cell progenitors, release molecules that are toxic to nearby and distant cells. Xu, Palmer et al. have now investigated if senescent cells interfere with the activity of stem cells from human fat tissue, and if getting rid of these senescent cells might restore the normal activity and insulin responsiveness of aged fat tissue. The experiments revealed that human senescent fat cell progenitors release a protein called activin A, which impedes the normal function of stem cells and fat tissue. Additionally, older mice had higher levels of activin A in both their blood and fat tissue than young mice. Xu, Palmer et al. then analyzed older mice that had been engineered to have senescent fat cells that could be triggered to essentially kill themselves when the mice were treated with a drug. Eliminating the senescent cells from these mice led to lower levels of activin A and more fat tissue (due to improved stem cell capacity to become fully functional fat cells) that expressed genes required for insulin responsiveness. This showed that senescent cells are a cause of age-related fat tissue loss and metabolic disease in older mice. Next, Xu, Palmer et al. treated older mice with drugs called JAK inhibitors, which they found reduce the production of activin A by senescent cells isolated from fat tissue. After two months of treatment, the levels of activin A in the blood and in fat tissue were indeed reduced. The fat tissue in treated mice also showed fewer features associated with the development of diabetes than the fat tissue of untreated mice. As such, these results paralleled those after selectively eliminating the senescent cells. Together these findings suggest that JAK inhibitors or drugs (called senolytics) that selectively eliminate senescent cells may have clinical benefits in treating age-related conditions such as diabetes and stem cell dysfunction. DOI:http://dx.doi.org/10.7554/eLife.12997.002
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Affiliation(s)
- Ming Xu
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Allyson K Palmer
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Husheng Ding
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Megan M Weivoda
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Tamar Pirtskhalava
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Thomas A White
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Anna Sepe
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Kurt O Johnson
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Michael B Stout
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Nino Giorgadze
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Michael D Jensen
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Nathan K LeBrasseur
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Tamar Tchkonia
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - James L Kirkland
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
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Pulido-Salgado M, Vidal-Taboada JM, Saura J. C/EBPβ and C/EBPδ transcription factors: Basic biology and roles in the CNS. Prog Neurobiol 2015; 132:1-33. [PMID: 26143335 DOI: 10.1016/j.pneurobio.2015.06.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 05/08/2015] [Accepted: 06/16/2015] [Indexed: 02/01/2023]
Abstract
CCAAT/enhancer binding protein (C/EBP) β and C/EBPδ are transcription factors of the basic-leucine zipper class which share phylogenetic, structural and functional features. In this review we first describe in depth their basic molecular biology which includes fascinating aspects such as the regulated use of alternative initiation codons in the C/EBPβ mRNA. The physical interactions with multiple transcription factors which greatly opens the number of potentially regulated genes or the presence of at least five different types of post-translational modifications are also remarkable molecular mechanisms that modulate C/EBPβ and C/EBPδ function. In the second part, we review the present knowledge on the localization, expression changes and physiological roles of C/EBPβ and C/EBPδ in neurons, astrocytes and microglia. We conclude that C/EBPβ and C/EBPδ share two unique features related to their role in the CNS: whereas in neurons they participate in memory formation and synaptic plasticity, in glial cells they regulate the pro-inflammatory program. Because of their role in neuroinflammation, C/EBPβ and C/EBPδ in microglia are potential targets for treatment of neurodegenerative disorders. Any strategy to reduce C/EBPβ and C/EBPδ activity in neuroinflammation needs to take into account its potential side-effects in neurons. Therefore, cell-specific treatments will be required for the successful application of this strategy.
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Affiliation(s)
- Marta Pulido-Salgado
- Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, planta 3, 08036 Barcelona, Spain
| | - Jose M Vidal-Taboada
- Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, planta 3, 08036 Barcelona, Spain
| | - Josep Saura
- Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, planta 3, 08036 Barcelona, Spain.
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15
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Yu H, He K, Wang L, Hu J, Gu J, Zhou C, Lu R, Jin Y. Stk40 represses adipogenesis through translational control of CCAAT/enhancer-binding proteins. J Cell Sci 2015; 128:2881-90. [PMID: 26065429 DOI: 10.1242/jcs.170282] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Accepted: 06/04/2015] [Indexed: 01/08/2023] Open
Abstract
A better understanding of molecular regulation in adipogenesis might help the development of efficient strategies to cope with obesity-related diseases. Here, we report that CCAAT/enhancer-binding protein (C/EBP) β and C/EBPδ, two crucial pro-adipogenic transcription factors, are controlled at a translational level by serine/threonine kinase 40 (Stk40). Genetic knockout (KO) or knockdown (KD) of Stk40 leads to increased protein levels of C/EBP proteins and adipocyte differentiation in mouse embryonic fibroblasts (MEFs), fetal liver stromal cells, and mesenchymal stem cells (MSCs). In contrast, overexpression of Stk40 abolishes the enhanced C/EBP protein translation and adipogenesis observed in Stk40-KO and -KD cells. Functionally, knockdown of C/EBPβ eliminates the enhanced adipogenic differentiation in Stk40-KO and -KD cells substantially. Mechanistically, deletion of Stk40 enhances phosphorylation of eIF4E-binding protein 1, leading to increased eIF4E-dependent translation of C/EBPβ and C/EBPδ. Knockdown of eIF4E in MSCs decreases translation of C/EBP proteins. Moreover, Stk40-KO fetal livers display an increased adipogenic program and aberrant lipid and steroid metabolism. Collectively, our study uncovers a new repressor of C/EBP protein translation as well as adipogenesis and provides new insights into the molecular mechanism underpinning the adipogenic program.
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Affiliation(s)
- Hongyao Yu
- Laboratory of Molecular Developmental Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Ke He
- Laboratory of Molecular Developmental Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Lina Wang
- Laboratory of Molecular Developmental Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Jing Hu
- Laboratory of Molecular Developmental Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Junjie Gu
- Laboratory of Molecular Developmental Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Chenlin Zhou
- Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Rui Lu
- Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Ying Jin
- Laboratory of Molecular Developmental Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
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16
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Growth hormone action predicts age-related white adipose tissue dysfunction and senescent cell burden in mice. Aging (Albany NY) 2015; 6:575-86. [PMID: 25063774 PMCID: PMC4153624 DOI: 10.18632/aging.100681] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The aging process is associated with the development of several chronic diseases. White adipose tissue (WAT) may play a central role in age-related disease onset and progression due to declines in adipogenesis with advancing age. Recent reports indicate that the accumulation of senescent progenitor cells may be involved in age-related WAT dysfunction. Growth hormone (GH) action has profound effects on adiposity and metabolism and is known to influence lifespan. In the present study we tested the hypothesis that GH activity would predict age-related WAT dysfunction and accumulation of senescent cells. We found that long-lived GH-deficient and -resistant mice have reduced age-related lipid redistribution. Primary preadipocytes from GH-resistant mice also were found to have greater differentiation capacity at 20 months of age when compared to controls. GH activity was also found to be positively associated with senescent cell accumulation in WAT. Our results demonstrate an association between GH activity, age-related WAT dysfunction, and WAT senescent cell accumulation in mice. Further studies are needed to determine if GH is directly inducing cellular senescence in WAT or if GH actions on other target organs or alternative downstream alterations in insulin-like growth factor-1, insulin or glucose levels are responsible.
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17
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Fu D, Lala-Tabbert N, Lee H, Wiper-Bergeron N. Mdm2 promotes myogenesis through the ubiquitination and degradation of CCAAT/enhancer-binding protein β. J Biol Chem 2015; 290:10200-7. [PMID: 25720496 DOI: 10.1074/jbc.m115.638577] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Indexed: 01/05/2023] Open
Abstract
Myogenesis is a tightly regulated differentiation process during which precursor cells express in a coordinated fashion the myogenic regulatory factors, while down-regulating the satellite cell marker Pax7. CCAAT/Enhancer-binding protein β (C/EBPβ) is also expressed in satellite cells and acts to maintain the undifferentiated state by stimulating Pax7 expression and by triggering a decrease in MyoD protein expression. Herein, we show that C/EBPβ protein is rapidly down-regulated upon induction of myogenesis and this is not due to changes in Cebpb mRNA expression. Rather, loss of C/EBPβ protein is accompanied by an increase in Mdm2 expression, an E3 ubiquitin ligase. We demonstrate that Mdm2 interacts with, ubiquitinates and targets C/EBPβ for degradation by the 26 S proteasome, leading to increased MyoD expression. Knockdown of Mdm2 expression in myoblasts using a shRNA resulted in high C/EBPβ levels and a blockade of myogenesis, indicating that Mdm2 is necessary for myogenic differentiation. Primary myoblasts expressing the shMdm2 construct were unable to contribute to muscle regeneration when grafted into cardiotoxin-injured muscle. The differentiation defect imposed by loss of Mdm2 could be partially rescued by loss of C/EBPβ, suggesting that the regulation of C/EBPβ turnover is a major role for Mdm2 in myoblasts. Taken together, we provide evidence that Mdm2 regulates entry into myogenesis by targeting C/EBPβ for degradation by the 26 S proteasome.
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Affiliation(s)
- Dechen Fu
- From the Department of Cellular and Molecular Medicine and
| | - Neena Lala-Tabbert
- Graduate Program in Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Hwabin Lee
- Graduate Program in Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
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18
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Ageing, adipose tissue, fatty acids and inflammation. Biogerontology 2014; 16:235-48. [PMID: 25367746 DOI: 10.1007/s10522-014-9536-x] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 10/20/2014] [Indexed: 12/22/2022]
Abstract
A common feature of ageing is the alteration in tissue distribution and composition, with a shift in fat away from lower body and subcutaneous depots to visceral and ectopic sites. Redistribution of adipose tissue towards an ectopic site can have dramatic effects on metabolic function. In skeletal muscle, increased ectopic adiposity is linked to insulin resistance through lipid mediators such as ceramide or DAG, inhibiting the insulin receptor signalling pathway. Additionally, the risk of developing cardiovascular disease is increased with elevated visceral adipose distribution. In ageing, adipose tissue becomes dysfunctional, with the pathway of differentiation of preadipocytes to mature adipocytes becoming impaired; this results in dysfunctional adipocytes less able to store fat and subsequent fat redistribution to ectopic sites. Low grade systemic inflammation is commonly observed in ageing, and may drive the adipose tissue dysfunction, as proinflammatory cytokines are capable of inhibiting adipocyte differentiation. Beyond increased ectopic adiposity, the effect of impaired adipose tissue function is an elevation in systemic free fatty acids (FFA), a common feature of many metabolic disorders. Saturated fatty acids can be regarded as the most detrimental of FFA, being capable of inducing insulin resistance and inflammation through lipid mediators such as ceramide, which can increase risk of developing atherosclerosis. Elevated FFA, in particular saturated fatty acids, maybe a driving factor for both the increased insulin resistance, cardiovascular disease risk and inflammation in older adults.
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Cardani R, Giagnacovo M, Rossi G, Renna LV, Bugiardini E, Pizzamiglio C, Botta A, Meola G. Progression of muscle histopathology but not of spliceopathy in myotonic dystrophy type 2. Neuromuscul Disord 2014; 24:1042-53. [PMID: 25139674 DOI: 10.1016/j.nmd.2014.06.435] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/07/2014] [Accepted: 06/17/2014] [Indexed: 12/25/2022]
Abstract
Myotonic dystrophy type 2 (DM2) is an autosomal dominant progressive disease involving skeletal and cardiac muscle and brain. It is caused by a tetranucleotide repeat within the first intron of the CNBP gene that leads to an alteration of the alternative splicing of several genes. To understand the molecular mechanisms that play a role in DM2 progression, the evolution of skeletal muscle histopathology and biomolecular findings in successive biopsies have been studied. Biceps brachii biopsies from 5 DM2 patients who underwent two successive biopsies at different years of age have been used. Muscle histopathology has been assessed on sections immunostained with fast or slow myosin. FISH in combination with MBNL1-immunofluorescence has been performed to evaluate ribonuclear inclusion and MBNL1 foci dimensions in myonuclei. Gene and protein expression and alteration of alternative splicing of several genes have been evaluated over time. All DM2 patients examined show a worsening of muscle histopathology and an increase of foci dimensions over time. The progressive worsening of myotonia in DM2 patients may be due to the decrease of CLCN1 mRNA observed in all patients examined. However, a worsening of alternative splicing alterations has not been evidenced over time. The data obtained in this study confirm that DM2 is a slow progression disease since histological and biomolecular alterations observed in skeletal muscle are minimal even after 10-year interval. The data indicate that muscle morphological alterations evolve more rapidly over time than the molecular changes thus indicating that muscle biopsy is a more sensitive tool than biomolecular markers to assess disease progression at muscle level.
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Affiliation(s)
- Rosanna Cardani
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, Milan, Italy
| | - Marzia Giagnacovo
- Department of Biology and Biotechnologies, University of Pavia, Pavia, Italy
| | - Giulia Rossi
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
| | - Laura V Renna
- Department of Biosciences, University of Milan, Milan, Italy
| | - Enrico Bugiardini
- Department of Neurology, University of Milan, IRCCS-Policlinico San Donato, Milan, Italy
| | - Chiara Pizzamiglio
- Department of Neurology, University of Milan, IRCCS-Policlinico San Donato, Milan, Italy
| | - Annalisa Botta
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
| | - Giovanni Meola
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, Milan, Italy; Department of Neurology, University of Milan, IRCCS-Policlinico San Donato, Milan, Italy.
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20
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Zamboni M, Rossi AP, Fantin F, Zamboni G, Chirumbolo S, Zoico E, Mazzali G. Adipose tissue, diet and aging. Mech Ageing Dev 2013; 136-137:129-37. [PMID: 24321378 DOI: 10.1016/j.mad.2013.11.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 11/14/2013] [Accepted: 11/27/2013] [Indexed: 12/25/2022]
Abstract
Age related increase in body fat mass, visceral adipose tissue (AT), and ectopic fat deposition are strongly related to worse health conditions in the elderly. Moreover, with aging higher inflammation in adipose tissue may be observed and may contribute to inflammaging. Aging may significantly affect AT function by modifying the profile of adipokines produced by adipose cells, reducing preadipocytes number and their function and increasing AT macrophages infiltration. The initiating events of the inflammatory cascade promoting a greater AT inflammatory profile are not completely understood. Nutrients may determine changes in the amount of body fat, in its distribution as well as in AT function with some nutrients showing a pro-inflammatory effect on AT. Evidences are sparse and quite controversial with only a few studies performed in older subjects. Different dietary patterns are the result of the complex interaction of foods and nutrients, thus more studies are needed to evaluate the association between dietary patterns and changes in adipose tissue structure, distribution and function in the elderly.
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Affiliation(s)
- Mauro Zamboni
- Department of Medicine, Geriatric Medicine, University of Verona, Italy.
| | - Andrea P Rossi
- Department of Medicine, Geriatric Medicine, University of Verona, Italy
| | - Francesco Fantin
- Department of Medicine, Geriatric Medicine, University of Verona, Italy
| | | | | | - Elena Zoico
- Department of Medicine, Geriatric Medicine, University of Verona, Italy
| | - Gloria Mazzali
- Department of Medicine, Geriatric Medicine, University of Verona, Italy
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Carter S, Caron A, Richard D, Picard F. Role of leptin resistance in the development of obesity in older patients. Clin Interv Aging 2013; 8:829-44. [PMID: 23869170 PMCID: PMC3706252 DOI: 10.2147/cia.s36367] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Obesity is a global epidemic associated with aging-like cellular processes; in both aging and obesity, resistance to hormones such as insulin and leptin can be observed. Leptin is a circulating hormone/cytokine with central and peripheral effects that is released mainly by subcutaneous white adipose tissue. Centrally, leptin controls food intake, energy expenditure, and fat distribution, whereas it controls (among several others) insulin sensitivity, free fatty acids (FFAs) oxidation, and lipolysis in the periphery. Aging is associated with important changes in both the distribution and the composition of adipose tissue. Fat is redistributed from the subcutaneous to the visceral depot and increased inflammation participates in adipocyte dysfunction. This redistribution of adipose tissue in favor of visceral fat influences negatively both longevity and healthy aging as shown in numerous animal models. These modifications observed during aging are also associated with leptin resistance. This resistance blunts normal central and peripheral functions of leptin, which leads to a decrease in neuroendocrine function and insulin sensitivity, an imbalance in energy regulation, and disturbances in lipid metabolism. Here, we review how age-related leptin resistance triggers metabolic disturbances and affects the longevity of obese patients. Furthermore, we discuss the potential impacts of leptin resistance on the decline of brown adipose tissue thermogenesis observed in elderly individuals.
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Affiliation(s)
- Sophie Carter
- Faculty of Pharmacy, Department of Anatomy and Physiology, Université Laval, Québec, QC, Canada
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22
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Gaya M, Repetto V, Toneatto J, Anesini C, Piwien-Pilipuk G, Moreno S. Antiadipogenic effect of carnosic acid, a natural compound present in Rosmarinus officinalis, is exerted through the C/EBPs and PPARγ pathways at the onset of the differentiation program. Biochim Biophys Acta Gen Subj 2013; 1830:3796-806. [DOI: 10.1016/j.bbagen.2013.03.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 02/21/2013] [Accepted: 03/20/2013] [Indexed: 01/24/2023]
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Mitterberger MC, Lechner S, Mattesich M, Zwerschke W. Adipogenic differentiation is impaired in replicative senescent human subcutaneous adipose-derived stromal/progenitor cells. J Gerontol A Biol Sci Med Sci 2013; 69:13-24. [PMID: 23657974 DOI: 10.1093/gerona/glt043] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We demonstrate that adipose-derived stromal/progenitor cells isolated from abdominal subcutaneous fat pads of adult donors successively enter replicative senescence after long-term cultivation. This is characterized by enlarged cell size, flattened morphology, and upregulated senescence-associated β-galactosidase activity. Moreover, the senescence- associated cyclin-dependent kinase inhibitors p16(Ink4A) and p21(Cip1) were induced correlating with activation of the G1/S cell cycle inhibitor retinoblastoma protein and terminal proliferation arrest. The number of cells in the adipose-derived stromal/progenitor cell population with high adipogenic capacity declined inversely with the increase of senescent cells. Adipogenic hormone cocktail induced expression of the adipogenic key regulators peroxisome proliferator-activated receptor-γ2 and CCAAT/enhancer-binding protein α was significantly reduced in senescent adipose-derived stromal/ progenitor cells. Furthermore, the expression of the adipogenic differentiation genes fatty acid binding protein-4, adiponectin, and leptin and the formation of fat droplets were impaired. We conclude cellular senescence contributes to dysfunctions in adipose-derived stromal/progenitor cell replication, adipogenesis, triglyceride storage, and adipokine secretion.
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24
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MicroRNA regulation of adipose derived stem cells in aging rats. PLoS One 2013; 8:e59238. [PMID: 23516615 PMCID: PMC3597632 DOI: 10.1371/journal.pone.0059238] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 02/14/2013] [Indexed: 12/11/2022] Open
Abstract
Background Perturbations in abdominal fat secreted adipokines play a key role in metabolic syndrome. This process is further altered during the aging process, probably due to alterations in the preadipocytes (aka. stromal vascular fraction cells-SVF cells or adipose derived stem cells-ASCs) composition and/or function. Since microRNAs regulate genes involved both in development and aging processes, we hypothesized that the impaired adipose function with aging is due to altered microRNA regulation of adipogenic pathways in SVF cells. Methodology and Principal Findings Alterations in mRNA and proteins associated with adipogenic differentiation (ERK5 and PPARg) but not osteogenic (RUNX2) pathways were observed in SVF cells isolated from visceral adipose tissue with aging (6 to 30 mo) in female Fischer 344 x Brown Norway Hybrid (FBN) rats. The impaired differentiation capacity with aging correlated with altered levels of miRNAs involved in adipocyte differentiation (miRNA-143) and osteogenic pathways (miRNA-204). Gain and loss of function studies using premir or antagomir-143 validated the age associated adipocyte dysfunction. Conclusions and Significance Our studies for the first time indicate a role for miRNA mediated regulation of SVF cells with aging. This discovery is important in the light of the findings that dysfunctional adipose derived stem cells contribute to age related chronic diseases.
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Vlasova-St Louis I, Dickson AM, Bohjanen PR, Wilusz CJ. CELFish ways to modulate mRNA decay. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:695-707. [PMID: 23328451 DOI: 10.1016/j.bbagrm.2013.01.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 01/03/2013] [Accepted: 01/05/2013] [Indexed: 12/14/2022]
Abstract
The CELF family of RNA-binding proteins regulates many steps of mRNA metabolism. Although their best characterized function is in pre-mRNA splice site choice, CELF family members are also powerful modulators of mRNA decay. In this review we focus on the different modes of regulation that CELF proteins employ to mediate mRNA decay by binding to GU-rich elements. After starting with an overview of the importance of CELF proteins during development and disease pathogenesis, we then review the mRNA networks and cellular pathways these proteins regulate and the mechanisms by which they influence mRNA decay. Finally, we discuss how CELF protein activity is modulated during development and in response to cellular signals. We conclude by highlighting the priorities for new experiments in this field. This article is part of a Special Issue entitled: RNA Decay mechanisms.
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Jones K, Timchenko L, Timchenko NA. The role of CUGBP1 in age-dependent changes of liver functions. Ageing Res Rev 2012; 11:442-9. [PMID: 22446383 DOI: 10.1016/j.arr.2012.02.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/09/2012] [Accepted: 02/10/2012] [Indexed: 12/14/2022]
Abstract
Aging liver is characterized by alterations of liver biology and by a reduction of many functions which are important for the maintenance of body homeostasis. The main dysfunctions include appearance of enlarged hepatocytes, impaired liver regeneration after partial hepatectomy (PH), development of hepatic steatosis, reduction of secretion of proteins and alterations in the hepatic sinusoid. RNA binding proteins are involved in the regulation of gene expression in all tissues including regulation of biological processes in the liver. This review is focused on the role of a conserved, multi-functional RNA-binding protein, CUGBP1, in the development of aging phenotype in the liver. CUGBP1 has been identified as a protein which binds to RNA CUG repeats expanded in Myotonic Dystrophy type 1 (DM1). CUGBP1 is highly expressed in the liver and regulates translation of proteins which are critical for maintenance of liver functions. In livers of young mice, CUGBP1 forms complexes with eukaryotic translation initiation factor eIF2 and supports translation of C/EBPβ and HDAC1 proteins, which are involved in liver growth, differentiation and liver cancer. Aging changes several signaling pathways which lead to the elevation of the CUGBP1-eIF2α complex and to an increase of translation of C/EBPβ and HDAC1. These proteins form multi-protein complexes with additional transcription factors and with chromatin remodeling proteins causing epigenetic alterations of gene expression in livers of old mice. It appears that CUGBP1-mediated translational elevation of HDAC1 is one of the key events in the epigenetic changes in livers of old mice, leading to the development of age-associated dysfunctions of the liver. This review will also discuss a possible role of CUGBP1 in liver dysfunction in patients affected with DM1.
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Karagiannides I, Bakirtzi K, Kokkotou E, Stavrakis D, Margolis KG, Thomou T, Giorgadze N, Kirkland JL, Pothoulakis C. Role of substance P in the regulation of glucose metabolism via insulin signaling-associated pathways. Endocrinology 2011; 152:4571-80. [PMID: 22009727 PMCID: PMC3230056 DOI: 10.1210/en.2011-1170] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Substance P (SP), encoded by the tachykinin 1 (Tac1) gene, is the most potent tachykinin ligand for the high-affinity neurokinin-1 receptor (NK-1R). We previously reported that NK-1R-deficient mice show less weight gain and reduced circulating levels of leptin and insulin in response to a high-fat diet (HFD) and demonstrated the presence of functional NK-1R in isolated human preadipocytes. Here we assessed the effects of SP on weight gain in response to HFD and determined glucose metabolism in Tac1-deficient (Tac1(-/-)) mice. The effect of SP on the expression of molecules that may predispose to reduced glucose uptake was also determined in isolated human mesenteric, omental, and sc preadipocytes. We show that although weight accumulation in response to HFD was similar between Tac1(-/-) mice and wild-type littermates, Tac1(-/-) mice demonstrated lower glucose and leptin and increased adiponectin blood levels and showed improved responses to insulin challenge after HFD. SP stimulated phosphorylation of c-Jun N-terminal kinase, protein kinase C, mammalian target of rapamycin, and inhibitory serine insulin receptor substrate-1 phosphorylation in human preadipocytes in vitro. Preincubation of human mesenteric preadipocytes with the protein kinase C pseudosubstrate inhibitor reduced insulin receptor substrate 1 phosphorylation in response to SP. Lastly, SP also induced insulin receptor substrate-1 phosphorylation in mature human sc adipocytes. Our results demonstrate an important role for SP in adipose tissue responses and obesity-associated pathologies. These novel SP effects on molecules that enhance insulin resistance at the adipocyte level may reflect an important role for this peptide in the pathophysiology of type 2 diabetes.
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Affiliation(s)
- Iordanes Karagiannides
- Inflammatory Bowel Disease Center, Division of Digestive Diseases, David Geffen School of Medicine, University of California at Los Angeles, 675 Charles E. Young Drive, Los Angeles, CA 90095, USA
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George SK, Jiao Y, Bishop CE, Lu B. Mitochondrial peptidase IMMP2L mutation causes early onset of age-associated disorders and impairs adult stem cell self-renewal. Aging Cell 2011; 10:584-94. [PMID: 21332923 DOI: 10.1111/j.1474-9726.2011.00686.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mitochondrial reactive oxygen species (ROS) are proposed to play a central role in aging and age-associated disorders, although direct in vivo evidence is lacking. We recently generated a mouse mutant with mutated inner mitochondrial membrane peptidase 2-like (Immp2l) gene, which impairs the signal peptide sequence processing of mitochondrial proteins cytochrome c1 and glycerol phosphate dehydrogenase 2. The mitochondria from mutant mice generate elevated levels of superoxide ion and cause impaired fertility in both sexes. Here, we design experiments to examine the effects of excessive mitochondrial ROS generation on health span. We show that Immp2l mutation increases oxidative stress in multiple organs such as the brain and the kidney, although expression of superoxide dismutases in these tissues of the mutants is also increased. The mutants show multiple aging-associated phenotypes, including wasting, sarcopenia, loss of subcutaneous fat, kyphosis, and ataxia, with female mutants showing earlier onset and more severe age-associated disorders than male mutants. The loss of body weight and fat was unrelated to food intake. Adipose-derived stromal cells (ADSC) from mutant mice showed impaired proliferation capability, formed significantly less and smaller colonies in colony formation assays, although they retained adipogenic differentiation capability in vitro. This functional impairment was accompanied by increased levels of oxidative stress. Our data showed that mitochondrial ROS is the driving force of accelerated aging and suggested that ROS damage to adult stem cells could be one of the mechanisms for age-associated disorders.
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Affiliation(s)
- Sunil K George
- Institute for Regenerative Medicine, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157, USA
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29
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Llamusí B, Artero R. Molecular Effects of the CTG Repeats in Mutant Dystrophia Myotonica Protein Kinase Gene. Curr Genomics 2011; 9:509-16. [PMID: 19516957 PMCID: PMC2694559 DOI: 10.2174/138920208786847944] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Revised: 06/18/2008] [Accepted: 06/24/2008] [Indexed: 11/22/2022] Open
Abstract
Myotonic Dystrophy type 1 (DM1) is a multi-system disorder characterized by muscle wasting, myotonia, cardiac conduction defects, cataracts, and neuropsychological dysfunction. DM1 is caused by expansion of a CTG repeat in the 3´untranslated region (UTR) of the Dystrophia Myotonica Protein Kinase (DMPK) gene. A body of work demonstrates that DMPK mRNAs containing abnormally expanded CUG repeats are toxic to several cell types. A core mechanism underlying symptoms of DM1 is that mutant DMPK RNA interferes with the developmentally regulated alternative splicing of defined pre-mRNAs. Expanded CUG repeats fold into ds(CUG) hairpins that sequester nuclear proteins including human Muscleblind-like (MBNL) and hnRNP H alternative splicing factors. DM1 cells activate CELF family member CUG-BP1 protein through hyperphosphorylation and stabilization in the cell nucleus. CUG-BP1 and MBNL1 proteins act antagonistically in exon selection in several pre-mRNA transcripts, thus MBNL1 sequestration and increase in nuclear activity of CUG-BP1 both act synergistically to missplice defined transcripts. Mutant DMPK-mediated effect on subcellular localization, and defective phosphorylation of cytoplasmic CUG-BP1, have additionally been linked to defective translation of p21 and MEF2A in DM1, possibly explaining delayed differentiation of DM1 muscle cells. Mutant DMPK transcripts bind and sequester transcription factors such as Specificity protein 1 leading to reduced transcription of selected genes. Recently, transcripts containing long hairpin structures of CUG repeats have been shown to be a Dicer ribonuclease target and Dicer-induced downregulation of the mutant DMPK transcripts triggers silencing effects on RNAs containing long complementary repeats. In summary, mutant DMPK transcripts alter gene transcription, alternative splicing, and translation of specific gene transcripts, and have the ability to trigger gene-specific silencing effects in DM1 cells. Therapies aimed at reversing these gene expression alterations should prove effective ways to treat DM1.
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Affiliation(s)
- Beatriz Llamusí
- Department of Genetics, University of Valencia, Doctor Moliner, 50, E46100 Burjasot, Valencia, Spain
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Abstract
To fulfill its role as the major energy-storing tissue, adipose has several unique properties that cannot be seen in any other organ, including an almost unlimited capacity to expand in a non-transformed state. As such, the tissue requires potent mechanisms to remodel, acutely and chronically. Adipocytes can rapidly reach the diffusional limit of oxygen during growth; hypoxia is therefore an early determinant that limits healthy expansion. Proper expansion requires a highly coordinated response among many different cell types, including endothelial precursor cells, immune cells, and preadipocytes. There are therefore remarkable similarities between adipose expansion and growth of solid tumors, a phenomenon that presents both an opportunity and a challenge, since pharmacological interventions supporting healthy adipose tissue adaptation can also facilitate tumor growth.
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Affiliation(s)
- Kai Sun
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8549, USA
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31
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Lee EK, Lee MJ, Abdelmohsen K, Kim W, Kim MM, Srikantan S, Martindale JL, Hutchison ER, Kim HH, Marasa BS, Selimyan R, Egan JM, Smith SR, Fried SK, Gorospe M. miR-130 suppresses adipogenesis by inhibiting peroxisome proliferator-activated receptor gamma expression. Mol Cell Biol 2011; 31:626-38. [PMID: 21135128 PMCID: PMC3028659 DOI: 10.1128/mcb.00894-10] [Citation(s) in RCA: 282] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 09/01/2010] [Accepted: 11/18/2010] [Indexed: 01/04/2023] Open
Abstract
Adipose tissue development is tightly regulated by altering gene expression. MicroRNAs are strong posttranscriptional regulators of mammalian differentiation. We hypothesized that microRNAs might influence human adipogenesis by targeting specific adipogenic factors. We identified microRNAs that showed varying abundance during the differentiation of human preadipocytes into adipocytes. Among them, miR-130 strongly affected adipocyte differentiation, as overexpressing miR-130 impaired adipogenesis and reducing miR-130 enhanced adipogenesis. A key effector of miR-130 actions was the protein peroxisome proliferator-activated receptor γ (PPARγ), a major regulator of adipogenesis. Interestingly, miR-130 potently repressed PPARγ expression by targeting both the PPARγ mRNA coding and 3' untranslated regions. Adipose tissue from obese women contained significantly lower miR-130 and higher PPARγ mRNA levels than that from nonobese women. Our findings reveal that miR-130 reduces adipogenesis by repressing PPARγ biosynthesis and suggest that perturbations in this regulation is linked to human obesity.
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Affiliation(s)
- Eun Kyung Lee
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
| | - Mi Jeong Lee
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
| | - Kotb Abdelmohsen
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
| | - Wook Kim
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
| | - Mihee M. Kim
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
| | - Subramanya Srikantan
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
| | - Jennifer L. Martindale
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
| | - Emmette R. Hutchison
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
| | - Hyeon Ho Kim
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
| | - Bernard S. Marasa
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
| | - Roza Selimyan
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
| | - Josephine M. Egan
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
| | - Steven R. Smith
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
| | - Susan K. Fried
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
| | - Myriam Gorospe
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, Maryland 21224, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, Laboratory of Clinical Investigation, NIA-IRP, NIH, Baltimore, Maryland 21224, Laboratory of Neurosciences, NIA-IRP, NIH, Baltimore, Maryland 21224, Translational Research Institute, Florida Hospital-Burnham Institute, Winter Park, Florida 32789
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Tchkonia T, Morbeck DE, Von Zglinicki T, Van Deursen J, Lustgarten J, Scrable H, Khosla S, Jensen MD, Kirkland JL. Fat tissue, aging, and cellular senescence. Aging Cell 2010; 9:667-84. [PMID: 20701600 PMCID: PMC2941545 DOI: 10.1111/j.1474-9726.2010.00608.x] [Citation(s) in RCA: 740] [Impact Index Per Article: 52.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Fat tissue, frequently the largest organ in humans, is at the nexus of mechanisms involved in longevity and age-related metabolic dysfunction. Fat distribution and function change dramatically throughout life. Obesity is associated with accelerated onset of diseases common in old age, while fat ablation and certain mutations affecting fat increase life span. Fat cells turn over throughout the life span. Fat cell progenitors, preadipocytes, are abundant, closely related to macrophages, and dysdifferentiate in old age, switching into a pro-inflammatory, tissue-remodeling, senescent-like state. Other mesenchymal progenitors also can acquire a pro-inflammatory, adipocyte-like phenotype with aging. We propose a hypothetical model in which cellular stress and preadipocyte overutilization with aging induce cellular senescence, leading to impaired adipogenesis, failure to sequester lipotoxic fatty acids, inflammatory cytokine and chemokine generation, and innate and adaptive immune response activation. These pro-inflammatory processes may amplify each other and have systemic consequences. This model is consistent with recent concepts about cellular senescence as a stress-responsive, adaptive phenotype that develops through multiple stages, including major metabolic and secretory readjustments, which can spread from cell to cell and can occur at any point during life. Senescence could be an alternative cell fate that develops in response to injury or metabolic dysfunction and might occur in nondividing as well as dividing cells. Consistent with this, a senescent-like state can develop in preadipocytes and fat cells from young obese individuals. Senescent, pro-inflammatory cells in fat could have profound clinical consequences because of the large size of the fat organ and its central metabolic role.
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Affiliation(s)
- Tamara Tchkonia
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA
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Zhou QG, Peng X, Hu LL, Xie D, Zhou M, Hou FF. Advanced oxidation protein products inhibit differentiation and activate inflammation in 3T3-L1 preadipocytes. J Cell Physiol 2010; 225:42-51. [DOI: 10.1002/jcp.22189] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Sepe A, Tchkonia T, Thomou T, Zamboni M, Kirkland JL. Aging and regional differences in fat cell progenitors - a mini-review. Gerontology 2010; 57:66-75. [PMID: 20110661 PMCID: PMC3031153 DOI: 10.1159/000279755] [Citation(s) in RCA: 158] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Accepted: 12/02/2009] [Indexed: 12/14/2022] Open
Abstract
Fat mass and fat tissue distribution change dramatically throughout life. In old age, fat becomes dysfunctional and is redistributed from subcutaneous to intra-abdominal visceral depots as well as other ectopic sites, including bone marrow, muscle and the liver. These changes are associated with increased risk of metabolic syndrome. Fat tissue is a nutrient storage, endocrine and immune organ that undergoes renewal throughout the lifespan. Preadipocytes, which account for 15-50% of cells in fat tissue, give rise to new fat cells. With aging, declines in preadipocyte proliferation and differentiation likely contribute to increased systemic exposure to lipotoxic free fatty acids. Age-related fat tissue inflammation is related to changes that occur in preadipocytes and macrophages in a fat depot-dependent manner. Fat tissue inflammation frequently leads to further reduction in adipogenesis with aging, more lipotoxicity and activation of cellular stress pathways that, in turn, exacerbate inflammatory responses of preadipocytes and immune cells, establishing self-perpetuating cycles that lead to systemic dysfunction. In this review, we will consider how inherent, age-related, depot-dependent alterations in preadipocyte function contribute to age-related fat tissue redistribution and metabolic dysfunction.
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Affiliation(s)
- Anna Sepe
- Department of Biomedical and Surgical Sciences, Division of Geriatrics, University of Verona, Verona, Italy
- Mayo Clinic Robert and Arlene Kogod Center on Aging, Rochester, Minn., USA
| | - Tamara Tchkonia
- Mayo Clinic Robert and Arlene Kogod Center on Aging, Rochester, Minn., USA
| | - Thomas Thomou
- Mayo Clinic Robert and Arlene Kogod Center on Aging, Rochester, Minn., USA
| | - Mauro Zamboni
- Department of Biomedical and Surgical Sciences, Division of Geriatrics, University of Verona, Verona, Italy
| | - James L. Kirkland
- Department of Biomedical and Surgical Sciences, Division of Geriatrics, University of Verona, Verona, Italy
- Mayo Clinic Robert and Arlene Kogod Center on Aging, Rochester, Minn., USA
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35
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Miard S, Dombrowski L, Carter S, Boivin L, Picard F. Aging alters PPARgamma in rodent and human adipose tissue by modulating the balance in steroid receptor coactivator-1. Aging Cell 2009; 8:449-59. [PMID: 19485965 DOI: 10.1111/j.1474-9726.2009.00490.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Age is an important risk factor for the development of metabolic diseases (e.g. obesity, diabetes and atherosclerosis). Yet, little is known about the molecular mechanisms occurring upon aging that affect energy metabolism. Although visceral white adipose tissue (vWAT) is known for its key impact on metabolism, recent studies have indicated it could also be a key regulator of lifespan, suggesting that it can serve as a node for age-associated fat accretion. Here we show that aging triggers changes in the transcriptional milieu of the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma) in vWAT, which leads to a modified potential for transactivation of target genes upon ligand treatment. We found that in vWAT of mice, rats and men, aging induced a specific decrease in the expression of steroid receptor coactivator-1 (SRC-1), whose recruitment to PPARgamma is associated with improved insulin sensitivity and low adipogenic activity. In contrast, aging and oxidative stress did not impact on PPARgamma expression and PPARgamma ligand production. Age-induced loss of PPARgamma/SRC-1 interactions increased the binding of PPARgamma to the promoter of the adipogenic gene aP2. These findings suggest that strategies aimed at increasing SRC-1 expression and recruitment to PPARgamma upon aging might help improve age-associated metabolic disorders.
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Affiliation(s)
- Stéphanie Miard
- Laval Hospital Research Center, Laval University, Québec, QC, Canada
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36
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Zoico E, Di Francesco V, Olioso D, Fratta Pasini AM, Sepe A, Bosello O, Cinti S, Cominacini L, Zamboni M. In vitro aging of 3T3-L1 mouse adipocytes leads to altered metabolism and response to inflammation. Biogerontology 2009; 11:111-22. [PMID: 19526322 DOI: 10.1007/s10522-009-9236-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Accepted: 05/28/2009] [Indexed: 11/29/2022]
Affiliation(s)
- Elena Zoico
- Division of Geriatric Medicine, University of Verona, Ospedale Maggiore-Piazzale Stefani 1, Verona, Italy.
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37
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Kim JY, Kim DH, Choi J, Park JK, Jeong KS, Leeuwenburgh C, Yu BP, Chung HY. Changes in lipid distribution during aging and its modulation by calorie restriction. AGE (DORDRECHT, NETHERLANDS) 2009; 31:127-142. [PMID: 19277901 PMCID: PMC2693731 DOI: 10.1007/s11357-009-9089-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Accepted: 02/17/2009] [Indexed: 05/27/2023]
Abstract
Adipogenesis and ectopic lipid accumulation during aging have a great impact on the aging process and the pathogenesis of chronic diseases with age. However, at present, information on the age-related molecular changes in lipid redistribution patterns and their potential nutritional interventions is sparse. We investigated the mechanism underlying age-related lipid redistribution and its modulation using 5-, 17-, and 24-month-old male Fischer 344 rats fed ad libitum (AL) or a 3-week-long CR (40% less than AL) diet. Results revealed that the activities of adipogenic transcription factors were decreased in the white adipose tissue (WAT) of aged AL rats. In contrast, the skeletal muscle of aged AL rats showed increased fat accumulation through decreased carnitine palmitoyltransferase-1 activity, which was blunted by short-term CR. This study suggests an age-related shift in lipid distribution by reducing the adipogenesis of WAT while increasing intramyocellular lipid accumulation, and that CR can modulate age-related adipogenesis and ectopic lipid accumulation.
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Affiliation(s)
- Ji Young Kim
- Department of Pharmacy, College of Pharmacy, Pusan National University, Gumjung-gu, Busan, 609-735 Korea
- Longevity Life Science and Technology Institutes, College of Pharmacy, Pusan National University, Busan, 609-735 South Korea
| | - Dae Hyun Kim
- Department of Pharmacy, College of Pharmacy, Pusan National University, Gumjung-gu, Busan, 609-735 Korea
| | - Jaehun Choi
- Department of Pharmacy, College of Pharmacy, Pusan National University, Gumjung-gu, Busan, 609-735 Korea
| | - Jin-Kyu Park
- Department of Veterinary Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 702-701 South Korea
| | - Kyu-Shik Jeong
- Department of Veterinary Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 702-701 South Korea
| | - Christiaan Leeuwenburgh
- Department of Aging and Geriatrics, College of Medicine, Institute on Aging, University of Florida, Gainesville, FL 32610-0267 USA
| | - Byung Pal Yu
- Department of Pharmacy, College of Pharmacy, Pusan National University, Gumjung-gu, Busan, 609-735 Korea
- Longevity Life Science and Technology Institutes, College of Pharmacy, Pusan National University, Busan, 609-735 South Korea
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900 USA
| | - Hae Young Chung
- Department of Pharmacy, College of Pharmacy, Pusan National University, Gumjung-gu, Busan, 609-735 Korea
- Longevity Life Science and Technology Institutes, College of Pharmacy, Pusan National University, Busan, 609-735 South Korea
- Department of Aging and Geriatrics, College of Medicine, Institute on Aging, University of Florida, Gainesville, FL 32610-0267 USA
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38
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Timchenko NA. Aging and liver regeneration. Trends Endocrinol Metab 2009; 20:171-6. [PMID: 19359195 DOI: 10.1016/j.tem.2009.01.005] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Revised: 01/14/2009] [Accepted: 01/15/2009] [Indexed: 12/12/2022]
Abstract
The loss of regenerative capacity is the most dramatic age-associated alteration in the liver. Although this phenomenon was reported over 50 years ago, the molecular basis for the loss of regenerative capacity of aged livers has not been fully elucidated. Aging causes alterations of several signal-transduction pathways and changes in the expression of CCAAT/enhancer-binding protein (C/EBP) and chromatin-remodeling proteins. Consequently, aging livers accumulate a multi-protein C/EBPalpha-Brm-HDAC1 complex that occupies and silences E2F-dependent promoters, reducing the regenerative capacity of livers in older mice. Recent studies have provided evidence for the crucial role of epigenetic silencing in the age-dependent inhibition of liver proliferation. This review focuses on mechanisms of age-dependent inhibition of liver proliferation and approaches for correcting liver regeneration in the elderly.
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Affiliation(s)
- Nikolai A Timchenko
- Department of Pathology and Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA.
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39
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Gupta V, Bhasin S, Guo W, Singh R, Miki R, Chauhan P, Choong K, Tchkonia T, Lebrasseur NK, Flanagan JN, Hamilton JA, Viereck JC, Narula NS, Kirkland JL, Jasuja R. Effects of dihydrotestosterone on differentiation and proliferation of human mesenchymal stem cells and preadipocytes. Mol Cell Endocrinol 2008; 296:32-40. [PMID: 18801408 PMCID: PMC2873614 DOI: 10.1016/j.mce.2008.08.019] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 07/29/2008] [Accepted: 08/10/2008] [Indexed: 10/21/2022]
Abstract
UNLABELLED The mechanisms by which androgens regulate fat mass are poorly understood. Although testosterone has been reported to increase lipolysis and inhibit lipid uptake, androgen effects on proliferation and differentiation of human mesenchymal stem cells (hMSCs) and preadipocytes have not been studied. Here, we investigated whether dihydrotestosterone (DHT) regulates proliferation, differentiation, or functional maturation of hMSCs and human preadipocytes from different fat depots. DHT (0-30 nM) dose-dependently inhibited lipid accumulation in adipocytes differentiated from hMSCs and downregulated expression of aP2, PPARgamma, leptin, and C/EBPalpha. Bicalutamide attenuated DHT's inhibitory effects on adipogenic differentiation of hMSCs. Adipocytes differentiated in presence of DHT accumulated smaller oil droplets suggesting reduced extent of maturation. DHT decreased the incorporation of labeled fatty acid into triglyceride, and downregulated acetyl CoA carboxylase and DGAT2 expression in adipocytes derived from hMSCs. DHT also inhibited lipid accumulation and downregulated aP2 and C/EBPalpha in human subcutaneous, mesenteric and omental preadipocytes. DHT stimulated forskolin-stimulated lipolysis in subcutaneous and mesenteric preadipocytes and inhibited incorporation of fatty acid into triglyceride in adipocytes differentiated from preadipocytes from all fat depots. CONCLUSIONS DHT inhibits adipogenic differentiation of hMSCs and human preadipocytes through an AR-mediated pathway, but it does not affect the proliferation of either hMSCs or preadipocytes. Androgen effects on fat mass represent the combined effect of decreased differentiation of fat cell precursors, increased lipolysis, and reduced lipid accumulation.
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Affiliation(s)
- Vandana Gupta
- Department of Medicine, Boston University, School of Medicine, Boston Medical Center, Boston, MA 02118, United States
| | - Shalender Bhasin
- Department of Medicine, Boston University, School of Medicine, Boston Medical Center, Boston, MA 02118, United States
| | - Wen Guo
- Department of Medicine, Boston University, School of Medicine, Boston Medical Center, Boston, MA 02118, United States
| | - Rajan Singh
- Charles R. Drew University, Los Angeles, CA 90059, United States
| | - Rika Miki
- Charles R. Drew University, Los Angeles, CA 90059, United States
| | - Pratibha Chauhan
- Department of Medicine, Boston University, School of Medicine, Boston Medical Center, Boston, MA 02118, United States
| | - Karen Choong
- Department of Medicine, Boston University, School of Medicine, Boston Medical Center, Boston, MA 02118, United States
| | - Tamara Tchkonia
- Department of Medicine, Boston University, School of Medicine, Boston Medical Center, Boston, MA 02118, United States
| | - Nathan K. Lebrasseur
- Department of Medicine, Boston University, School of Medicine, Boston Medical Center, Boston, MA 02118, United States
| | - John N. Flanagan
- Department of Medicine, Boston University, School of Medicine, Boston Medical Center, Boston, MA 02118, United States
| | - James A. Hamilton
- Department of Biophysics, Boston University, School of Medicine, Boston Medical Center, Boston, MA 02118, United States
| | - Jason C. Viereck
- Department of Biophysics, Boston University, School of Medicine, Boston Medical Center, Boston, MA 02118, United States
| | - Navjot S. Narula
- Department of Medicine, Boston University, School of Medicine, Boston Medical Center, Boston, MA 02118, United States
| | - James L. Kirkland
- Department of Medicine, Boston University, School of Medicine, Boston Medical Center, Boston, MA 02118, United States
| | - Ravi Jasuja
- Department of Medicine, Boston University, School of Medicine, Boston Medical Center, Boston, MA 02118, United States
- Charles R. Drew University, Los Angeles, CA 90059, United States
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40
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Ectopic expression of cyclin D3 corrects differentiation of DM1 myoblasts through activation of RNA CUG-binding protein, CUGBP1. Exp Cell Res 2008; 314:2266-78. [PMID: 18570922 DOI: 10.1016/j.yexcr.2008.04.018] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 04/02/2008] [Accepted: 04/22/2008] [Indexed: 11/20/2022]
Abstract
Differentiation of myocytes is impaired in patients with myotonic dystrophy type 1, DM1. CUG repeat binding protein, CUGBP1, is a key regulator of translation of proteins that are involved in muscle development and differentiation. In this paper, we present evidence that RNA-binding activity of CUGBP1 and its interactions with initiation translation complex eIF2 are differentially regulated during myogenesis by specific phosphorylation and that this regulation is altered in DM1. In normal myoblasts, Akt kinase phosphorylates CUGBP1 at Ser28 and increases interactions of CUGBP1 with cyclin D1 mRNA. During differentiation, CUGBP1 is phosphorylated by cyclinD3-cdk4/6 at Ser302, which increases CUGBP1 binding with p21 and C/EBPbeta mRNAs. While cyclin D3 and cdk4 are elevated in normal myotubes; DM1 differentiating cells do not increase these proteins. In normal myotubes, CUGBP1 interacts with cyclin D3/cdk4/6 and eIF2; however, interactions of CUGBP1 with eIF2 are reduced in DM1 differentiating cells and correlate with impaired muscle differentiation in DM1. Ectopic expression of cyclin D3 in DM1 cells increases the CUGBP1-eIF2 complex, corrects expression of differentiation markers, myogenin and desmin, and enhances fusion of DM1 myoblasts. Thus, normalization of cyclin D3 might be a therapeutic approach to correct differentiation of skeletal muscle in DM1 patients.
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41
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Tchkonia T, Pirtskhalava T, Thomou T, Cartwright MJ, Wise B, Karagiannides I, Shpilman A, Lash TL, Becherer JD, Kirkland JL. Increased TNFalpha and CCAAT/enhancer-binding protein homologous protein with aging predispose preadipocytes to resist adipogenesis. Am J Physiol Endocrinol Metab 2007; 293:E1810-9. [PMID: 17911345 DOI: 10.1152/ajpendo.00295.2007] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fat depot sizes peak in middle age but decrease by advanced old age. This phenomenon is associated with ectopic fat deposition, decreased adipocyte size, impaired differentiation of preadipocytes into fat cells, decreased adipogenic transcription factor expression, and increased fat tissue inflammatory cytokine generation. To define the mechanisms contributing to impaired adipogenesis with aging, we examined the release of TNFalpha, which inhibits adipogenesis, and the expression of CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP), which blocks activity of adipogenic C/EBP family members, in preadipocytes cultured from young, middle-aged, and old rats. Medium conditioned by fat tissue, as well as preadipocytes, from old rats impeded lipid accumulation by preadipocytes from young animals. More TNFalpha was released by preadipocytes from old than young rats. Differences in TNFalpha-converting enzyme, TNFalpha degradation, or the presence of macrophages in cultures were not responsible. TNFalpha induced rat preadipocyte CHOP expression. CHOP was higher in undifferentiated preadipocytes from old than younger animals. Overexpression of CHOP in young rat preadipocytes inhibited lipid accumulation. TNFalpha short interference RNA reduced CHOP and partially restored lipid accumulation in old rat preadipocytes. CHOP normally increases during late differentiation, potentially modulating the process. This late increase in CHOP was not affected substantially by aging: CHOP was similar in differentiating preadipocytes and fat tissue from old and young animals. Hypoglycemia, which normally causes an adaptive increase in CHOP, was less effective in inducing CHOP in preadipocytes from old than younger animals. Thus increased TNFalpha release by undifferentiated preadipocytes with elevated basal CHOP contributes to impaired adipogenesis with aging.
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Affiliation(s)
- Tamara Tchkonia
- Evans Department of Medicine, Boston Univ. Medical Center, 88 E. Newton St., Robinson 2, Boston, MA 02118, USA
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42
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Choi WT, Folsom MR, Azim MF, Meyer C, Kowarz E, Marschalek R, Timchenko NA, Naeem RC, Lee DA. C/EBPbeta suppression by interruption of CUGBP1 resulting from a complex rearrangement of MLL. ACTA ACUST UNITED AC 2007; 177:108-14. [PMID: 17854664 PMCID: PMC3311538 DOI: 10.1016/j.cancergencyto.2007.07.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Revised: 06/14/2007] [Accepted: 07/02/2007] [Indexed: 01/25/2023]
Abstract
Translocations involving the mixed-lineage leukemia gene (MLL) confer a poor prognosis in acute leukemias. In t(1;11)(q21;q23), MLL is fused reciprocally with AF1q. Here we describe a t(1;11)(q21;q23) with a secondary event involving insertion of the telomeric portion of MLL into the p arm of chromosome 11 (11p11). We show that this latter event interrupts the CUG triplet repeat binding protein-1 (CUGBP1) gene, a translational enhancer of C/EBPbeta. We then showed that these cells have reduced expression of CUGBP1 and C/EBPbeta when compared to other AML blasts. This is the first report to describe insertional disruption of the CUGBP1 gene and to suggest a role for the CUGBP1-C/EBPbeta pathway in leukemogenesis.
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MESH Headings
- Acute Disease
- Base Sequence
- Blotting, Western
- CCAAT-Enhancer-Binding Protein-beta/antagonists & inhibitors
- CCAAT-Enhancer-Binding Protein-beta/genetics
- CCAAT-Enhancer-Binding Protein-beta/metabolism
- CELF1 Protein
- Child
- Chromosomes, Human, Pair 1/genetics
- Chromosomes, Human, Pair 11/genetics
- Female
- Gene Expression Regulation, Neoplastic
- Gene Rearrangement
- Histone-Lysine N-Methyltransferase
- Humans
- In Situ Hybridization, Fluorescence
- Infant
- Karyotyping
- Leukemia, Myeloid/genetics
- Leukemia, Myeloid/metabolism
- Leukemia, Myeloid/pathology
- Molecular Sequence Data
- Myeloid-Lymphoid Leukemia Protein/genetics
- Nucleic Acid Hybridization
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Nucleic Acid
- Translocation, Genetic
- Zinc Fingers
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Affiliation(s)
- William T. Choi
- Division of Pediatrics, Cell Therapy Section, University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Pediatrics Research Unit #853, Houston, TX 77030-4009
| | - Matthew R. Folsom
- Department of Pediatrics, Hematology/Oncology Section, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030
- The Texas Children’s Cancer Center Cytogenetics Core Laboratory, Texas Children’s Hospital, 6621 Fannin, MC 3-3320, Houston, TX
| | - Mohammed F. Azim
- The Texas Children’s Cancer Center Cytogenetics Core Laboratory, Texas Children’s Hospital, 6621 Fannin, MC 3-3320, Houston, TX
| | - Claus Meyer
- Institute of Pharmaceutical Biology/ZAFES/Diagnostic Center of Acute Leukemia, University of Frankfurt, Max-von Laue-Str. 9, Frankfurt/Main, D-60438, Germany
| | - Eric Kowarz
- Institute of Pharmaceutical Biology/ZAFES/Diagnostic Center of Acute Leukemia, University of Frankfurt, Max-von Laue-Str. 9, Frankfurt/Main, D-60438, Germany
| | - Rolf Marschalek
- Institute of Pharmaceutical Biology/ZAFES/Diagnostic Center of Acute Leukemia, University of Frankfurt, Max-von Laue-Str. 9, Frankfurt/Main, D-60438, Germany
| | - Nikolai A. Timchenko
- Huffington Center on Aging and Department of Pathology, Baylor College of Medicine, Houston, TX
| | - Rizwan C. Naeem
- Department of Pediatrics, Hematology/Oncology Section, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030
- The Texas Children’s Cancer Center Cytogenetics Core Laboratory, Texas Children’s Hospital, 6621 Fannin, MC 3-3320, Houston, TX
| | - Dean A. Lee
- Division of Pediatrics, Cell Therapy Section, University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Pediatrics Research Unit #853, Houston, TX 77030-4009
- Corresponding author. Tel.: 713-563-5404; fax: 713-563-5406. (D.A. Lee)
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43
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Huichalaf CH, Sakai K, Wang GL, Timchenko NA, Timchenko L. Regulation of the promoter of CUG triplet repeat binding protein, Cugbp1, during myogenesis. Gene 2007; 396:391-402. [PMID: 17531403 DOI: 10.1016/j.gene.2007.04.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Revised: 04/04/2007] [Accepted: 04/09/2007] [Indexed: 11/18/2022]
Abstract
CUG triplet repeat binding protein, CUGBP1, plays a critical role in the development of skeletal muscle pathology in patients with Myotonic Dystrophy 1 (DM1). In this paper, we have characterized transcriptional regulation of mouse Cugbp1 gene during normal myogenesis. There are several Cugbp1 mRNA species with variable 5' ends. We found that these mRNA species have different patterns of expression during myogenesis. Isoforms 1 and 2 are mainly expressed in myotubes, while expression of isoform 3 is increased during transition of myoblasts to myotubes and during transition of myotubes to myofibers. We have cloned a short region of the Cugbp1 promoter, which is responsible for the regulation of the isoform 3, and have identified within this region three different transcription start sites. This promoter region exhibits high activity in myoblasts and the activity of this region is significantly increased in myotubes. The Cugbp1 promoter contains three E-box elements. A mutation of one of the E-boxes, E(3), significantly reduces activity of the Cugbp1 promoter. Gelshift and ChIP assays showed that E(3)-box is occupied by E12, CBP and p300 proteins in myoblasts, while in differentiated myotubes this element is occupied by myogenin, E12 and p300. The binding of myogenin to the Cugbp1 promoter correlates with activation of the promoter during differentiation. Our data show that myogenin is a key regulator of the Cugbp1 promoter since overexpression of myogenin increases the activity of the Cugbp1 promoter; while the inhibition of myogenin reduces activity of the Cugbp1 promoter. These data show that transcription of Cugbp1 gene in muscle is regulated by myogenin and E proteins and suggest that the co-operation of several transcription factors is important for the activation of the Cugbp1 promoter.
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Affiliation(s)
- Claudia H Huichalaf
- Department of Medicine, Section of Cardiovascular Sciences, Baylor College of Medicine, One Baylor Plaza, Houston Texas 77030, USA
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44
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Guo W, Pirtskhalava T, Tchkonia T, Xie W, Thomou T, Han J, Wang T, Wong S, Cartwright A, Hegardt FG, Corkey BE, Kirkland JL. Aging results in paradoxical susceptibility of fat cell progenitors to lipotoxicity. Am J Physiol Endocrinol Metab 2007; 292:E1041-51. [PMID: 17148751 DOI: 10.1152/ajpendo.00557.2006] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Aging is associated with metabolic syndrome, tissue damage by cytotoxic lipids, and altered fatty acid handling. Fat tissue dysfunction may contribute to these processes. This could result, in part, from age-related changes in preadipocytes, since they give rise to new fat cells throughout life. To test this hypothesis, preadipocytes cultured from rats of different ages were exposed to oleic acid, the most abundant fatty acyl moiety in fat tissue and the diet. At fatty acid concentrations at which preadipocytes from young animals remained viable, cells from old animals accumulated lipid in multiple small lipid droplets and died, with increased apoptotic index, caspase activity, BAX, and p53. Rather than inducing apoptosis, oleic acid promoted adipogenesis in preadipocytes from young animals, with appearance of large lipid droplets. CCAAT/enhancer-binding protein-alpha (C/EBPalpha) and peroxisome proliferator-activated receptor-gamma (PPARgamma) increased to a greater extent in cells from young than old animals after oleate exposure. Oleic acid, but not glucose, oxidation was impaired in preadipocytes and fat cells from old animals. Expression of carnitine palmitoyltransferase (CPT)-1, which catalyzes the rate-limiting step in fatty acid beta-oxidation, was not reduced in preadipocytes from old animals. At lower fatty acid levels, constitutively active CPT I expression enhanced beta-oxidation. At higher levels, CPT I was not as effective in enhancing beta-oxidation in preadipocytes from old as young animals, suggesting that mitochondrial dysfunction may contribute. Consistent with this, medium-chain acyl-CoA dehydrogenase expression was reduced in preadipocytes from old animals. Thus preadipocyte fatty acid handling changes with aging, with increased susceptibly to lipotoxicity and impaired fatty acid-induced adipogenesis and beta-oxidation.
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Affiliation(s)
- Wen Guo
- Evans Department of Medicine, Obesity Research Center, Boston University Medical Center, 88 E. Newton St., Boston, MA 02118, USA
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45
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Cartwright MJ, Tchkonia T, Kirkland JL. Aging in adipocytes: potential impact of inherent, depot-specific mechanisms. Exp Gerontol 2007; 42:463-71. [PMID: 17507194 PMCID: PMC1961638 DOI: 10.1016/j.exger.2007.03.003] [Citation(s) in RCA: 212] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 02/28/2007] [Accepted: 03/06/2007] [Indexed: 12/25/2022]
Abstract
Fat mass and tissue distribution change dramatically throughout life. Fat depot sizes reach a peak by middle or early old age, followed by a substantial decline, together with fat tissue dysfunction and redistribution in advanced old age. These changes are associated with health complications, including type 2 diabetes, atherosclerosis, dyslipidemia, thermal dysregulation, and skin ulcers, particularly in advanced old age. Fat tissue growth occurs through increases in size and number of fat cells. Fat cells turn over throughout the lifespan, with new fat cells developing from preadipocytes, which are of mesenchymal origin. The pool of preadipocytes comprises 15-50% of the cells in fat tissue. Since fat tissue turns over throughout life, characteristics of these cells very likely have a significant impact on fat tissue growth, plasticity, function, and distribution. The aims of this review are to highlight recent findings regarding changes in preadipocyte cell dynamics and function with aging, and to consider how inherent characteristics of these cells potentially contribute to age- and depot-dependent changes in fat tissue development and function.
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Affiliation(s)
- Mark J Cartwright
- Department of Medicine, Section of Geriatrics, Boston University Medical Center, 650 Albany St., Boston, MA 02118, USA
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