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McGrath C, Little-Letsinger SE, Pagnotti GM, Sen B, Xie Z, Uzer G, Uzer GB, Zong X, Styner MA, Rubin J, Styner M. Diet-Stimulated Marrow Adiposity Fails to Worsen Early, Age-Related Bone Loss. Obes Facts 2024; 17:145-157. [PMID: 38224679 PMCID: PMC10987189 DOI: 10.1159/000536159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 01/04/2024] [Indexed: 01/17/2024] Open
Abstract
INTRODUCTION Longitudinal effect of diet-induced obesity on bone is uncertain. Prior work showed both no effect and a decrement in bone density or quality when obesity begins prior to skeletal maturity. We aimed to quantify long-term effects of obesity on bone and bone marrow adipose tissue (BMAT) in adulthood. METHODS Skeletally mature, female C57BL/6 mice (n = 70) aged 12 weeks were randomly allocated to low-fat diet (LFD; 10% kcal fat; n = 30) or high-fat diet (HFD; 60% kcal fat; n = 30), with analyses at 12, 15, 18, and 24 weeks (n = 10/group). Tibial microarchitecture was analyzed by µCT, and volumetric BMAT was quantified via 9.4T MRI/advanced image analysis. Histomorphometry of adipocytes and osteoclasts, and qPCR were performed. RESULTS Body weight and visceral white adipose tissue accumulated in response to HFD started in adulthood. Trabecular bone parameters declined with advancing experimental age. BV/TV declined 22% in LFD (p = 0.0001) and 17% in HFD (p = 0.0022) by 24 weeks. HFD failed to appreciably alter BV/TV and had negligible impact on other microarchitecture parameters. Both dietary intervention and age accounted for variance in BMAT, with regional differences: distal femoral BMAT was more responsive to diet, while proximal femoral BMAT was more attenuated by age. BMAT increased 60% in the distal metaphysis in HFD at 18 and 24 weeks (p = 0.0011). BMAT in the proximal femoral diaphysis, unchanged by diet, decreased 45% due to age (p = 0.0002). Marrow adipocyte size via histomorphometry supported MRI quantification. Osteoclast number did not differ between groups. Tibial qPCR showed attenuation of some adipose, metabolism, and bone genes. A regulator of fatty acid β-oxidation, cytochrome C (CYCS), was 500% more abundant in HFD bone (p < 0.0001; diet effect). CYCS also increased due to age, but to a lesser extent. HFD mildly increased OCN, TRAP, and SOST. CONCLUSIONS Long-term high fat feeding after skeletal maturity, despite upregulation of visceral adiposity, body weight, and BMAT, failed to attenuate bone microarchitecture. In adulthood, we found aging to be a more potent regulator of microarchitecture than diet-induced obesity.
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Affiliation(s)
- Cody McGrath
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Sarah E. Little-Letsinger
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Gabriel M. Pagnotti
- Department of Endocrine, Neoplasia and Hormonal Disorders, MD Anderson Cancer Center, Houston, TX, USA
| | - Buer Sen
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Zhihui Xie
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Gunes Uzer
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Guniz B. Uzer
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Xiaopeng Zong
- Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Martin A. Styner
- Departments of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Psychiatry, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Janet Rubin
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Maya Styner
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Wen ZQ, Lin J, Xie WQ, Shan YH, Zhen GH, Li YS. Insights into the underlying pathogenesis and therapeutic potential of endoplasmic reticulum stress in degenerative musculoskeletal diseases. Mil Med Res 2023; 10:54. [PMID: 37941072 PMCID: PMC10634069 DOI: 10.1186/s40779-023-00485-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 10/09/2023] [Indexed: 11/10/2023] Open
Abstract
Degenerative musculoskeletal diseases are structural and functional failures of the musculoskeletal system, including osteoarthritis, osteoporosis, intervertebral disc degeneration (IVDD), and sarcopenia. As the global population ages, degenerative musculoskeletal diseases are becoming more prevalent. However, the pathogenesis of degenerative musculoskeletal diseases is not fully understood. Previous studies have revealed that endoplasmic reticulum (ER) stress is a stress response that occurs when impairment of the protein folding capacity of the ER leads to the accumulation of misfolded or unfolded proteins in the ER, contributing to degenerative musculoskeletal diseases. By affecting cartilage degeneration, synovitis, meniscal lesion, subchondral bone remodeling of osteoarthritis, bone remodeling and angiogenesis of osteoporosis, nucleus pulposus degeneration, annulus fibrosus rupture, cartilaginous endplate degeneration of IVDD, and sarcopenia, ER stress is involved in the pathogenesis of degenerative musculoskeletal diseases. Preclinical studies have found that regulation of ER stress can delay the progression of multiple degenerative musculoskeletal diseases. These pilot studies provide foundations for further evaluation of the feasibility, efficacy, and safety of ER stress modulators in the treatment of musculoskeletal degenerative diseases in clinical trials. In this review, we have integrated up-to-date research findings of ER stress into the pathogenesis of degenerative musculoskeletal diseases. In a future perspective, we have also discussed possible directions of ER stress in the investigation of degenerative musculoskeletal disease, potential therapeutic strategies for degenerative musculoskeletal diseases using ER stress modulators, as well as underlying challenges and obstacles in bench-to-beside research.
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Affiliation(s)
- Ze-Qin Wen
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, 410008, China
- Xiangya School of Medicine, Central South University, Changsha, 410013, China
| | - Jun Lin
- Department of Orthopaedics, Suzhou Dushu Lake Hospital, Dushu Lake Hospital Affiliated to Soochow University, Medical Center of Soochow University, Suzhou, 215001, China
| | - Wen-Qing Xie
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Yun-Han Shan
- Xiangya School of Medicine, Central South University, Changsha, 410013, China
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Ge-Hua Zhen
- Department of Orthopaedic Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.
| | - Yu-Sheng Li
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, 410008, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, China.
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Zhong M, Wu Z, Chen Z, Ren Q, Zhou J. Advances in the interaction between endoplasmic reticulum stress and osteoporosis. Biomed Pharmacother 2023; 165:115134. [PMID: 37437374 DOI: 10.1016/j.biopha.2023.115134] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 07/04/2023] [Accepted: 07/07/2023] [Indexed: 07/14/2023] Open
Abstract
The endoplasmic reticulum (ER) is the main site for protein synthesis, folding, and secretion, and accumulation of the unfolded/misfolded proteins in the ER may induce ER stress. ER stress is an important participant in various intracellular signaling pathways. Prolonged- or high-intensity ER stress may induce cell apoptosis. Osteoporosis, characterized by imbalanced bone remodeling, is a global disease caused by many factors, such as ER stress. ER stress stimulates osteoblast apoptosis, increases bone loss, and promotes osteoporosis development. Many factors, such as the drug's adverse effects, metabolic disorders, calcium ion imbalance, bad habits, and aging, have been reported to activate ER stress, resulting in the pathological development of osteoporosis. Increasing evidence shows that ER stress regulates osteogenic differentiation, osteoblast activity, and osteoclast formation and function. Various therapeutic agents have been developed to counteract ER stress and thereby suppress osteoporosis development. Thus, inhibition of ER stress has become a potential target for the therapeutic management of osteoporosis. However, the in-depth understanding of ER stress in the pathogenesis of osteoporosis still needs more effort.
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Affiliation(s)
- Mingliang Zhong
- College of Rehabilitation, Gannan Medical University, Ganzhou 341000, China
| | - Zhenyu Wu
- First Affiliated Hospital of Gannan Medical University, Ganzhou 341000, China
| | - Zhixi Chen
- College of Pharmacy, Gannan Medical University, Ganzhou 341000, China
| | - Qun Ren
- College of Pharmacy, Gannan Medical University, Ganzhou 341000, China
| | - Jianguo Zhou
- Department of Joint Surgery, Ganzhou People's Hospital, Ganzhou 341000, China.
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Smith N, Shirazi S, Cakouros D, Gronthos S. Impact of Environmental and Epigenetic Changes on Mesenchymal Stem Cells during Aging. Int J Mol Sci 2023; 24:ijms24076499. [PMID: 37047469 PMCID: PMC10095074 DOI: 10.3390/ijms24076499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/22/2023] [Accepted: 03/28/2023] [Indexed: 03/31/2023] Open
Abstract
Many crucial epigenetic changes occur during early skeletal development and throughout life due to aging, disease and are heavily influenced by an individual’s lifestyle. Epigenetics is the study of heritable changes in gene expression as the result of changes in the environment without any mutation in the underlying DNA sequence. The epigenetic profiles of cells are dynamic and mediated by different mechanisms, including histone modifications, non-coding RNA-associated gene silencing and DNA methylation. Given the underlining role of dysfunctional mesenchymal tissues in common age-related skeletal diseases such as osteoporosis and osteoarthritis, investigations into skeletal stem cells or mesenchymal stem cells (MSC) and their functional deregulation during aging has been of great interest and how this is mediated by an evolving epigenetic landscape. The present review describes the recent findings in epigenetic changes of MSCs that effect growth and cell fate determination in the context of aging, diet, exercise and bone-related diseases.
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Affiliation(s)
- Nicholas Smith
- Mesenchymal Stem Cell Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5001, Australia
- Precision Medicine Theme, South Australian Health and Medical Research Institute, Adelaide, SA 5001, Australia
| | - Suzanna Shirazi
- Mesenchymal Stem Cell Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5001, Australia
- Precision Medicine Theme, South Australian Health and Medical Research Institute, Adelaide, SA 5001, Australia
| | - Dimitrios Cakouros
- Mesenchymal Stem Cell Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5001, Australia
- Precision Medicine Theme, South Australian Health and Medical Research Institute, Adelaide, SA 5001, Australia
- Correspondence: (D.C.); (S.G.); Tel.: +61-8-8128-4395 (S.G.)
| | - Stan Gronthos
- Mesenchymal Stem Cell Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5001, Australia
- Precision Medicine Theme, South Australian Health and Medical Research Institute, Adelaide, SA 5001, Australia
- Correspondence: (D.C.); (S.G.); Tel.: +61-8-8128-4395 (S.G.)
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Little-Letsinger SE, Rubin J, Diekman B, Rubin CT, McGrath C, Pagnotti GM, Klett EL, Styner M. Exercise to Mend Aged-tissue Crosstalk in Bone Targeting Osteoporosis & Osteoarthritis. Semin Cell Dev Biol 2022; 123:22-35. [PMID: 34489173 PMCID: PMC8840966 DOI: 10.1016/j.semcdb.2021.08.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 08/16/2021] [Accepted: 08/19/2021] [Indexed: 12/16/2022]
Abstract
Aging induces alterations in bone structure and strength through a multitude of processes, exacerbating common aging- related diseases like osteoporosis and osteoarthritis. Cellular hallmarks of aging are examined, as related to bone and the marrow microenvironment, and ways in which these might contribute to a variety of age-related perturbations in osteoblasts, osteocytes, marrow adipocytes, chondrocytes, osteoclasts, and their respective progenitors. Cellular senescence, stem cell exhaustion, mitochondrial dysfunction, epigenetic and intracellular communication changes are central pathways and recognized as associated and potentially causal in aging. We focus on these in musculoskeletal system and highlight knowledge gaps in the literature regarding cellular and tissue crosstalk in bone, cartilage, and the bone marrow niche. While senolytics have been utilized to target aging pathways, here we propose non-pharmacologic, exercise-based interventions as prospective "senolytics" against aging effects on the skeleton. Increased bone mass and delayed onset or progression of osteoporosis and osteoarthritis are some of the recognized benefits of regular exercise across the lifespan. Further investigation is needed to delineate how cellular indicators of aging manifest in bone and the marrow niche and how altered cellular and tissue crosstalk impact disease progression, as well as consideration of exercise as a therapeutic modality, as a means to enhance discovery of bone-targeted therapies.
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Affiliation(s)
- SE Little-Letsinger
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina at Chapel Hill
| | - J Rubin
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina at Chapel Hill,North Carolina Diabetes Research Center (NCDRC), University of North Carolina at Chapel Hill,Department of Medicine, Thurston Arthritis Research Center (TARC), University of North Carolina at Chapel Hill
| | - B Diekman
- Department of Medicine, Thurston Arthritis Research Center (TARC), University of North Carolina at Chapel Hill,Joint Departments of Biomedical Engineering NC State & University of North Carolina at Chapel Hill
| | - CT Rubin
- Department of Biomedical Engineering, State University of New York at Stony Brook
| | - C McGrath
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina at Chapel Hill
| | - GM Pagnotti
- Dept of Endocrine, Neoplasia, and Hormonal Disorders, University Texas MD Anderson Cancer Center, Houston
| | - EL Klett
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina at Chapel Hill,Department of Nutrition, School of Public Health, University of North Carolina at Chapel Hill
| | - M Styner
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina at Chapel Hill,North Carolina Diabetes Research Center (NCDRC), University of North Carolina at Chapel Hill,Department of Medicine, Thurston Arthritis Research Center (TARC), University of North Carolina at Chapel Hill
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6
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McGrath C, Little-Letsinger SE, Sankaran JS, Sen B, Xie Z, Styner MA, Zong X, Chen W, Rubin J, Klett EL, Coleman RA, Styner M. Exercise Increases Bone in SEIPIN Deficient Lipodystrophy, Despite Low Marrow Adiposity. Front Endocrinol (Lausanne) 2021; 12:782194. [PMID: 35145475 PMCID: PMC8822583 DOI: 10.3389/fendo.2021.782194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/20/2021] [Indexed: 01/12/2023] Open
Abstract
Exercise, typically beneficial for skeletal health, has not yet been studied in lipodystrophy, a condition characterized by paucity of white adipose tissue, with eventual diabetes, and steatosis. We applied a mouse model of global deficiency of Bscl2 (SEIPIN), required for lipid droplet formation. Male twelve-week-old B6 knockouts (KO) and wild type (WT) littermates were assigned six-weeks of voluntary, running exercise (E) versus non-exercise (N=5-8). KO weighed 14% less than WT (p=0.01) and exhibited an absence of epididymal adipose tissue; KO liver Plin1 via qPCR was 9-fold that of WT (p=0.04), consistent with steatosis. Bone marrow adipose tissue (BMAT), unlike white adipose, was measurable, although 40.5% lower in KO vs WT (p=0.0003) via 9.4T MRI/advanced image analysis. SEIPIN ablation's most notable effect marrow adiposity was in the proximal femoral diaphysis (-56% KO vs WT, p=0.005), with relative preservation in KO-distal-femur. Bone via μCT was preserved in SEIPIN KO, though some quality parameters were attenuated. Running distance, speed, and time were comparable in KO and WT. Exercise reduced weight (-24% WT-E vs WT p<0.001) but not in KO. Notably, exercise increased trabecular BV/TV in both (+31%, KO-E vs KO, p=0.004; +14%, WT-E vs WT, p=0.006). The presence and distribution of BMAT in SEIPIN KO, though lower than WT, is unexpected and points to a uniqueness of this depot. That trabecular bone increases were achievable in both KO and WT, despite a difference in BMAT quantity/distribution, points to potential metabolic flexibility during exercise-induced skeletal anabolism.
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Affiliation(s)
- Cody McGrath
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Sarah E. Little-Letsinger
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Jeyantt Srinivas Sankaran
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Buer Sen
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Zhihui Xie
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Martin A. Styner
- Department of Psychiatry, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Xiaopeng Zong
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Weiqin Chen
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Janet Rubin
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- North Carolina Diabetes Research Center (NCDRC), Chapel Hill, NC, United States
| | - Eric L. Klett
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- North Carolina Diabetes Research Center (NCDRC), Chapel Hill, NC, United States
- Department of Nutrition, Gillings School of Global Public Health, UNC, Chapel Hill, NC, United States
| | - Rosalind A. Coleman
- Department of Nutrition, Gillings School of Global Public Health, UNC, Chapel Hill, NC, United States
| | - Maya Styner
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- North Carolina Diabetes Research Center (NCDRC), Chapel Hill, NC, United States
- *Correspondence: Maya Styner,
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Little-Letsinger SE, Pagnotti GM, McGrath C, Styner M. Exercise and Diet: Uncovering Prospective Mediators of Skeletal Fragility in Bone and Marrow Adipose Tissue. Curr Osteoporos Rep 2020; 18:774-789. [PMID: 33068251 PMCID: PMC7736569 DOI: 10.1007/s11914-020-00634-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/29/2020] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW To highlight recent basic, translational, and clinical works demonstrating exercise and diet regulation of marrow adipose tissue (MAT) and bone and how this informs current understanding of the relationship between marrow adiposity and musculoskeletal health. RECENT FINDINGS Marrow adipocytes accumulate in the bone in the setting of not only hypercaloric intake (calorie excess; e.g., diet-induced obesity) but also with hypocaloric intake (calorie restriction; e.g., anorexia), despite the fact that these states affect bone differently. With hypercaloric intake, bone quantity is largely unaffected, whereas with hypocaloric intake, bone quantity and quality are greatly diminished. Voluntary running exercise in rodents was found to lower MAT and promote bone in eucaloric and hypercaloric states, while degrading bone in hypocaloric states, suggesting differential modulation of MAT and bone, dependent upon whole-body energy status. Energy status alters bone metabolism and bioenergetics via substrate availability or excess, which plays a key role in the response of bone and MAT to mechanical stimuli. Marrow adipose tissue (MAT) is a fat depot with a potential role in-as well as responsivity to-whole-body energy metabolism. Understanding the localized function of this depot in bone cell bioenergetics and substrate storage, principally in the exercised state, will aid to uncover putative therapeutic targets for skeletal fragility.
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Affiliation(s)
- Sarah E Little-Letsinger
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina, Chapel Hill, NC, USA.
| | - Gabriel M Pagnotti
- Department of Medicine, Division of Endocrinology, Indiana University, Indianapolis, IN, USA
| | - Cody McGrath
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina, Chapel Hill, NC, USA
| | - Maya Styner
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina, Chapel Hill, NC, USA
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Alcorta-Sevillano N, Macías I, Rodríguez CI, Infante A. Crucial Role of Lamin A/C in the Migration and Differentiation of MSCs in Bone. Cells 2020; 9:cells9061330. [PMID: 32466483 PMCID: PMC7348862 DOI: 10.3390/cells9061330] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/22/2020] [Accepted: 05/25/2020] [Indexed: 12/17/2022] Open
Abstract
Lamin A/C, intermediate filament proteins from the nuclear lamina encoded by the LMNA gene, play a central role in mediating the mechanosignaling of cytoskeletal forces into nucleus. In fact, this mechanotransduction process is essential to ensure the proper functioning of other tasks also mediated by lamin A/C: the structural support of the nucleus and the regulation of gene expression. In this way, lamin A/C is fundamental for the migration and differentiation of mesenchymal stem cells (MSCs), the progenitors of osteoblasts, thus affecting bone homeostasis. Bone formation is a complex process regulated by chemical and mechanical cues, coming from the surrounding extracellular matrix. MSCs respond to signals modulating the expression levels of lamin A/C, and therefore, adapting their nuclear shape and stiffness. To promote cell migration, MSCs need soft nuclei with low lamin A content. Conversely, during osteogenic differentiation, lamin A/C levels are known to be increased. Several LMNA mutations present a negative impact in the migration and osteogenesis of MSCs, affecting bone tissue homeostasis and leading to pathological conditions. This review aims to describe these concepts by discussing the latest state-of-the-art in this exciting area, focusing on the relationship between lamin A/C in MSCs' function and bone tissue from both, health and pathological points of view.
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McGrath C, Sankaran JS, Misaghian‐Xanthos N, Sen B, Xie Z, Styner MA, Zong X, Rubin J, Styner M. Exercise Degrades Bone in Caloric Restriction, Despite Suppression of Marrow Adipose Tissue (MAT). J Bone Miner Res 2020; 35:106-115. [PMID: 31509274 PMCID: PMC6980282 DOI: 10.1002/jbmr.3872] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 08/13/2019] [Accepted: 08/30/2019] [Indexed: 01/06/2023]
Abstract
Marrow adipose tissue (MAT) and its relevance to skeletal health during caloric restriction (CR) is unknown: It remains unclear whether exercise, which is anabolic to bone in a calorie-replete state, alters bone or MAT in CR. We hypothesized that response of bone and MAT to exercise in CR differs from the calorie-replete state. Ten-week-old female B6 mice fed a regular diet (RD) or 30% CR diet were allocated to sedentary (RD, CR, n = 10/group) or running exercise (RD-E, CR-E, n = 7/group). After 6 weeks, CR mice weighed 20% less than RD, p < 0.001; exercise did not affect weight. Femoral bone volume (BV) via 3D MRI was 20% lower in CR versus RD (p < 0.0001). CR was associated with decreased bone by μCT: Tb.Th was 16% less in CR versus RD, p < 0.003, Ct.Th was 5% less, p < 0.07. In CR-E, Tb.Th was 40% less than RD-E, p < 0.0001. Exercise increased Tb.Th in RD (+23% RD-E versus RD, p < 0.003) but failed to do so in CR. Cortical porosity increased after exercise in CR (+28%, p = 0.04), suggesting exercise during CR is deleterious to bone. In terms of bone fat, metaphyseal MAT/ BV rose 159% in CR versus RD, p = 0.003 via 3D MRI. Exercise decreased MAT/BV by 52% in RD, p < 0.05, and also suppressed MAT in CR (-121%, p = 0.047). Histomorphometric analysis of adipocyte area correlated with MAT by MRI (R2 = 0.6233, p < 0.0001). With respect to bone, TRAP and Sost mRNA were reduced in CR. Intriguingly, the repressed Sost in CR rose with exercise and may underlie the failure of CR-bone quantity to increase in response to exercise. Notably, CD36, a marker of fatty acid uptake, rose 4088% in CR (p < 0.01 versus RD), suggesting that basal increases in MAT during calorie restriction serve to supply local energy needs and are depleted during exercise with a negative impact on bone. © 2019 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.
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Affiliation(s)
- Cody McGrath
- Department of Medicine, Division of EndocrinologyUniversity of North CarolinaChapel HillNCUSA
| | - Jeyantt S Sankaran
- Department of Medicine, Division of EndocrinologyUniversity of North CarolinaChapel HillNCUSA
| | - Negin Misaghian‐Xanthos
- Department of Medicine, Division of EndocrinologyUniversity of North CarolinaChapel HillNCUSA
| | - Buer Sen
- Department of Medicine, Division of EndocrinologyUniversity of North CarolinaChapel HillNCUSA
| | - Zhihui Xie
- Department of Medicine, Division of EndocrinologyUniversity of North CarolinaChapel HillNCUSA
| | - Martin A Styner
- Department of Computer ScienceUniversity of North CarolinaChapel HillNCUSA
- Department of PsychiatryUniversity of North CarolinaChapel HillNCUSA
| | - Xiaopeng Zong
- Biomedical Research Imaging CenterUniversity of North CarolinaChapel HillNCUSA
| | - Janet Rubin
- Department of Medicine, Division of EndocrinologyUniversity of North CarolinaChapel HillNCUSA
| | - Maya Styner
- Department of Medicine, Division of EndocrinologyUniversity of North CarolinaChapel HillNCUSA
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10
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Curtis KJ, Oberman AG, Niebur GL. Effects of mechanobiological signaling in bone marrow on skeletal health. Ann N Y Acad Sci 2019; 1460:11-24. [PMID: 31508828 DOI: 10.1111/nyas.14232] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/09/2019] [Accepted: 08/15/2019] [Indexed: 01/27/2023]
Abstract
Bone marrow is a cellular tissue that forms within the pore space and hollow diaphysis of bones. As a tissue, its primary function is to support the hematopoietic progenitor cells that maintain the populations of both erythroid and myeloid lineage cells in the bone marrow, making it an essential element of normal mammalian physiology. However, bone's primary function is load bearing, and deformations induced by external forces are transmitted to the encapsulated marrow. Understanding the effects of these mechanical inputs on marrow function and adaptation requires knowledge of the material behavior of the marrow at multiple scales, the loads that are applied, and the mechanobiology of the cells. This paper reviews the current state of knowledge of each of these factors. Characterization of the marrow mechanical environment and its role in skeletal health and other marrow functions remains incomplete, but research on the topic is increasing, driven by interest in skeletal adaptation and the mechanobiology of cancer metastasis.
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Affiliation(s)
- Kimberly J Curtis
- Tissue Mechanics Laboratory, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, Indiana.,Advanced Diagnostics and Therapeutics Initiative, University of Notre Dame, Notre Dame, Indiana
| | - Alyssa G Oberman
- Tissue Mechanics Laboratory, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, Indiana
| | - Glen L Niebur
- Tissue Mechanics Laboratory, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, Indiana.,Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana.,Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana
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11
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Qin M, Zou Y, Zhong K, Guo Y, Zou X. Expression of S100A8 is induced by interleukin‑1α in TR146 epithelial cells through a mechanism involving CCAAT/enhancer binding protein β. Mol Med Rep 2019; 19:2413-2420. [PMID: 30664211 DOI: 10.3892/mmr.2019.9864] [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: 07/06/2018] [Accepted: 12/11/2018] [Indexed: 11/06/2022] Open
Abstract
Calprotectin in mucosal epidermal keratinocytes has an important role in fighting microbial infections. S100A8 belongs to the S100 protein family and is a subunit of calprotectin (heterodimer complex of S100A8/A9). Interleukin‑1α (IL‑1α) is one of the cytokines produced by oral keratinocytes. The primary aims of the present study were to investigate the effect of IL‑1α on the expression of S100A8 and its underlying molecular mechanism in oral epithelial cells. Determining the molecular mechanism of the induced expression of S100A8 by IL‑1α aims to improve current understanding of the roles of calprotectin during the infection of mucosal epithelial cells. The expression analysis indicated that IL‑1α significantly induced the expression of S100A8 in human TR146 epithelial cells at the mRNA and protein levels, respectively. The reporter assay demonstrated that the upregulatory effect of S100A8 induced by IL‑1α was dependent on the S100A8 promoter specific region (‑165/‑111). The results of electrophoresis mobility shift assay and chromatin immunoprecipitation assay also demonstrated that the CCAAT/enhancer binding protein β (C/EBPβ) binding site (‑113/‑109) in the S100A8 promoter region was involved into the upregulatory effect on the expression of S100A8 induced by IL‑1α. Taken together, these results suggested that the activation of the expression of S100A8 induced by IL‑1α in TR146 epithelial cells involves a mechanism by which the binding activity of C/EBPβ to the specific site (‑113/‑109) of the S100A8 promoter is increased.
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Affiliation(s)
- Mingqun Qin
- Laboratory of Mucosal Immunology, Guilin Medical University, Guilin, Guangxi 541100, P.R. China
| | - Yantao Zou
- Laboratory of Mucosal Immunology, Guilin Medical University, Guilin, Guangxi 541100, P.R. China
| | - Kanghua Zhong
- Laboratory of Mucosal Immunology, Guilin Medical University, Guilin, Guangxi 541100, P.R. China
| | - Yong Guo
- Laboratory of Mucosal Immunology, Guilin Medical University, Guilin, Guangxi 541100, P.R. China
| | - Xianqiong Zou
- Laboratory of Mucosal Immunology, Guilin Medical University, Guilin, Guangxi 541100, P.R. China
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12
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Kim HK, Kang YG, Jeong SH, Park N, Marquez J, Ko KS, Rhee BD, Shin JW, Han J. Cyclic stretch increases mitochondrial biogenesis in a cardiac cell line. Biochem Biophys Res Commun 2018; 505:768-774. [PMID: 30297109 DOI: 10.1016/j.bbrc.2018.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 10/01/2018] [Indexed: 11/27/2022]
Abstract
Unlike stable and immobile cell line conditions, animal hearts contract and relax to pump blood throughout the body. Mitochondria play an essential role by producing biological energy molecules to maintain heart function. In this study, we assessed the effect of heart mimetic cyclic stretch on mitochondria in a cardiac cell line. To mimic the geometric and biomechanical conditions surrounding cells in vivo, cyclic stretching was performed on HL-1 murine cardiomyocytes seeded onto an elastic micropatterned substrate (10% elongation, 0.5 Hz, 4 h/day). Cell viability, semi-quantitative Q-PCR, and western blot analyses were performed in non-stimulated control and cyclic stretch stimulated HL-1 cell lines. Cyclic stretch significantly increased the expression of mitochondria biogenesis-related genes (TUFM, TFAM, ERRα, and PGC1-α) and mitochondria oxidative phosphorylation-related genes (PHB1 and CYTB). Western blot analysis confirmed that cyclic stretch increased protein levels of mitochondria biogenesis-related proteins (TFAM, and ERRα) and oxidative phosphorylation-related proteins (NDUFS1, UQCRC, and PHB1). Consequently, cyclic stretch increased mitochondrial mass and ATP production in treated cells. Our results suggest that cyclic stretch transcriptionally enhanced mitochondria biogenesis and oxidative phosphorylation without detrimental effects in a cultured cardiac cell line.
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Affiliation(s)
- Hyoung Kyu Kim
- Cardiovascular and Metabolic Disease Center, Department of Physiology, Department of Health Sciences and Technology, BK21 Plus Project Team, College of Medicine, Bokji-ro 75, Busanjin-gu, Busan, 47392, South Korea; Department of Integrated Biomedical Science, College of Medicine, Inje University, Busanjin-gu, Busan, 47392, South Korea
| | - Yun Gyeong Kang
- Department of Biomedical Engineering, Inje University, Gimhae, Gyeongsangnam-do, 50834, South Korea
| | - Seung Hun Jeong
- Cardiovascular and Metabolic Disease Center, Department of Physiology, Department of Health Sciences and Technology, BK21 Plus Project Team, College of Medicine, Bokji-ro 75, Busanjin-gu, Busan, 47392, South Korea
| | - Nammi Park
- Cardiovascular and Metabolic Disease Center, Department of Physiology, Department of Health Sciences and Technology, BK21 Plus Project Team, College of Medicine, Bokji-ro 75, Busanjin-gu, Busan, 47392, South Korea
| | - Jubert Marquez
- Cardiovascular and Metabolic Disease Center, Department of Physiology, Department of Health Sciences and Technology, BK21 Plus Project Team, College of Medicine, Bokji-ro 75, Busanjin-gu, Busan, 47392, South Korea
| | - Kyung Soo Ko
- Cardiovascular and Metabolic Disease Center, Department of Physiology, Department of Health Sciences and Technology, BK21 Plus Project Team, College of Medicine, Bokji-ro 75, Busanjin-gu, Busan, 47392, South Korea
| | - Byoung Doo Rhee
- Cardiovascular and Metabolic Disease Center, Department of Physiology, Department of Health Sciences and Technology, BK21 Plus Project Team, College of Medicine, Bokji-ro 75, Busanjin-gu, Busan, 47392, South Korea
| | - Jung-Woog Shin
- Department of Biomedical Engineering, Inje University, Gimhae, Gyeongsangnam-do, 50834, South Korea.
| | - Jin Han
- Cardiovascular and Metabolic Disease Center, Department of Physiology, Department of Health Sciences and Technology, BK21 Plus Project Team, College of Medicine, Bokji-ro 75, Busanjin-gu, Busan, 47392, South Korea.
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13
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Rubin J, Styner M, Uzer G. Physical Signals May Affect Mesenchymal Stem Cell Differentiation via Epigenetic Controls. Exerc Sport Sci Rev 2018; 46:42-47. [PMID: 28795956 DOI: 10.1249/jes.0000000000000129] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Marrow mesenchymal stem cells supply bone osteoblasts and adipocytes. Exercise effects to increase bone and decrease fat involve transfer of signals from the cytoplasm into the nucleus to regulate gene expression. We propose that exercise control of stem cell fate relies on structural connections that terminate in the nucleus and involve intranuclear actin structures that regulate epigenetic gene expression.
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Affiliation(s)
- Janet Rubin
- Department of Medicine, University of North Carolina, Chapel Hill, NC
| | - Maya Styner
- Department of Medicine, University of North Carolina, Chapel Hill, NC
| | - Gunes Uzer
- Department of Medicine, University of North Carolina, Chapel Hill, NC
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14
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Ding S, Gan T, Song M, Dai Q, Huang H, Xu Y, Zhong C. C/EBPB-CITED4 in Exercised Heart. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1000:247-259. [PMID: 29098625 DOI: 10.1007/978-981-10-4304-8_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
C/EBPB is a crucial transcription factor, participating in a variety of biological processes including cell proliferation, differentiation and development. In the cardiovascular system, C/EBPB-CITED4 signaling is known as a signaling pathway mediating exercise-induced cardiac growth. After its exact role in exercised heart firstly reported in 2010, more and more evidence confirmed that. MicroRNA (e.g. miR-222) and many molecules (e.g. Alpha-lipoic acid) can regulate this pathway and then involve in the cardiac protection effect induced by endurance exercise training. In addition, in cardiac growth during pregnancy, C/EBPB is also a required regulator. This chapter will give an introduction of the C/EBPB-CITED4 signaling and the regulatory network based on this signaling pathway in exercised heart.
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Affiliation(s)
- Shengguang Ding
- Department of Thoracic and Cardiovascular Surgery, The Second Affiliated Hospital of Nantong University, Nantong, 226001, China
| | - Tianyi Gan
- State Key Laboratory of Cardiovascular Disease, Heart Failure Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China
| | - Meiyi Song
- Division of Gastroenterology and Hepatology, Digestive Disease Institute, Shanghai Tongji Hospital, Tongji University School of Medicine, 389 Xin Cun Road, Shanghai, 200065, China
| | - Qiying Dai
- Metrowest Medical Center, Framingham, 01702, MA, USA.,Department of Cardiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Haitao Huang
- Department of Thoracic and Cardiovascular Surgery, The Second Affiliated Hospital of Nantong University, Nantong, 226001, China
| | - Yiming Xu
- Department of Thoracic and Cardiovascular Surgery, The Second Affiliated Hospital of Nantong University, Nantong, 226001, China
| | - Chongjun Zhong
- Department of Thoracic and Cardiovascular Surgery, The Second Affiliated Hospital of Nantong University, Nantong, 226001, China.
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15
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RUBIN JANET, SEN BUER. Actin up in the Nucleus: Regulation of Actin Structures Modulates Mesenchymal Stem Cell Differentiation. TRANSACTIONS OF THE AMERICAN CLINICAL AND CLIMATOLOGICAL ASSOCIATION 2017; 128:180-192. [PMID: 28790502 PMCID: PMC5525393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Stem cells respond to environmental signals that induce their differentiation to cells that make up specialized tissues and organs. Our laboratory has focused on bone marrow mesenchymal stem cells (MSCs) that supply bone osteoblasts and marrow adipocytes, an output that appears to be reciprocal. Case in point: exercise promotes osteogenesis and bone formation, and inhibits marrow adipose accrual. A mechanically induced signal pathway concentrating on preserving β-catenin also causes increased structure of the actin cytoskeleton, both of which inhibit adipogenesis. Recently we showed that intranuclear actin is as important to MSC lineage decisions as cytoplasmic actin. This opens up new areas for understanding gene expression in stem cells.
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Affiliation(s)
- JANET RUBIN
- Correspondence and reprint requests: Janet Rubin, UNC School of Medicine,
5030 Burnette-Womack, CB #7170, Chapel Hill, North Carolina 27599919-966-6744
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16
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Yang Y, Cheung HH, Tu J, Miu KK, Chan WY. New insights into the unfolded protein response in stem cells. Oncotarget 2016; 7:54010-54027. [PMID: 27304053 PMCID: PMC5288239 DOI: 10.18632/oncotarget.9833] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 05/29/2016] [Indexed: 12/15/2022] Open
Abstract
The unfolded protein response (UPR) is an evolutionarily conserved adaptive mechanism to increase cell survival under endoplasmic reticulum (ER) stress conditions. The UPR is critical for maintaining cell homeostasis under physiological and pathological conditions. The vital functions of the UPR in development, metabolism and immunity have been demonstrated in several cell types. UPR dysfunction activates a variety of pathologies, including cancer, inflammation, neurodegenerative disease, metabolic disease and immune disease. Stem cells with the special ability to self-renew and differentiate into various somatic cells have been demonstrated to be present in multiple tissues. These cells are involved in development, tissue renewal and certain disease processes. Although the role and regulation of the UPR in somatic cells has been widely reported, the function of the UPR in stem cells is not fully known, and the roles and functions of the UPR are dependent on the stem cell type. Therefore, in this article, the potential significances of the UPR in stem cells, including embryonic stem cells, tissue stem cells, cancer stem cells and induced pluripotent cells, are comprehensively reviewed. This review aims to provide novel insights regarding the mechanisms associated with stem cell differentiation and cancer pathology.
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Affiliation(s)
- Yanzhou Yang
- Key Laboratory of Fertility Preservation and Maintenance, Ministry of Education, Key Laboratory of Reproduction and Genetics in Ningxia, Department of Histology and Embryology, Ningxia Medical University, Yinchuan, Ningxia, P.R. China
- The Chinese University of Hong Kong–Shandong University Joint Laboratory on Reproductive Genetics, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, HKSAR, China
| | - Hoi Hung Cheung
- The Chinese University of Hong Kong–Shandong University Joint Laboratory on Reproductive Genetics, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, HKSAR, China
| | - JiaJie Tu
- The Chinese University of Hong Kong–Shandong University Joint Laboratory on Reproductive Genetics, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, HKSAR, China
| | - Kai Kei Miu
- The Chinese University of Hong Kong–Shandong University Joint Laboratory on Reproductive Genetics, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, HKSAR, China
| | - Wai Yee Chan
- The Chinese University of Hong Kong–Shandong University Joint Laboratory on Reproductive Genetics, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, HKSAR, China
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17
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Meyer MB, Benkusky NA, Sen B, Rubin J, Pike JW. Epigenetic Plasticity Drives Adipogenic and Osteogenic Differentiation of Marrow-derived Mesenchymal Stem Cells. J Biol Chem 2016; 291:17829-47. [PMID: 27402842 DOI: 10.1074/jbc.m116.736538] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Indexed: 12/11/2022] Open
Abstract
Terminal differentiation of multipotent stem cells is achieved through a coordinated cascade of activated transcription factors and epigenetic modifications that drive gene transcription responsible for unique cell fate. Within the mesenchymal lineage, factors such as RUNX2 and PPARγ are indispensable for osteogenesis and adipogenesis, respectively. We therefore investigated genomic binding of transcription factors and accompanying epigenetic modifications that occur during osteogenic and adipogenic differentiation of mouse bone marrow-derived mesenchymal stem cells (MSCs). As assessed by ChIP-sequencing and RNA-sequencing analyses, we found that genes vital for osteogenic identity were linked to RUNX2, C/EBPβ, retinoid X receptor, and vitamin D receptor binding sites, whereas adipocyte differentiation favored PPARγ, retinoid X receptor, C/EBPα, and C/EBPβ binding sites. Epigenetic marks were clear predictors of active differentiation loci as well as enhancer activities and selective gene expression. These marrow-derived MSCs displayed an epigenetic pattern that suggested a default preference for the osteogenic pathway; however, these patterns were rapidly altered near the Adipoq, Cidec, Fabp4, Lipe, Plin1, Pparg, and Cebpa genes during adipogenic differentiation. Surprisingly, we found that these cells also exhibited an epigenetic plasticity that enabled them to trans-differentiate from adipocytes to osteoblasts (and vice versa) after commitment, as assessed by staining, gene expression, and ChIP-quantitative PCR analysis. The osteogenic default pathway may be subverted during pathological conditions, leading to skeletal fragility and increased marrow adiposity during aging, estrogen deficiency, and skeletal unloading. Taken together, our data provide an increased mechanistic understanding of the epigenetic programs necessary for multipotent differentiation of MSCs that may prove beneficial in the development of therapeutic strategies.
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Affiliation(s)
- Mark B Meyer
- From the Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706 and
| | - Nancy A Benkusky
- From the Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706 and
| | - Buer Sen
- the Department of Medicine, University of North Carolina, Chapel Hill, North Carolina 27514
| | - Janet Rubin
- the Department of Medicine, University of North Carolina, Chapel Hill, North Carolina 27514
| | - J Wesley Pike
- From the Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706 and
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18
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Pagnotti GM, Styner M. Exercise Regulation of Marrow Adipose Tissue. Front Endocrinol (Lausanne) 2016; 7:94. [PMID: 27471493 PMCID: PMC4943947 DOI: 10.3389/fendo.2016.00094] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 07/04/2016] [Indexed: 12/20/2022] Open
Abstract
Despite association with low bone density and skeletal fractures, marrow adipose tissue (MAT) remains poorly understood. The marrow adipocyte originates from the mesenchymal stem cell (MSC) pool that also gives rise to osteoblasts, chondrocytes, and myocytes, among other cell types. To date, the presence of MAT has been attributed to preferential biasing of MSC into the adipocyte rather than osteoblast lineage, thus negatively impacting bone formation. Here, we focus on understanding the physiology of MAT in the setting of exercise, dietary interventions, and pharmacologic agents that alter fat metabolism. The beneficial effect of exercise on musculoskeletal strength is known: exercise induces bone formation, encourages growth of skeletally supportive tissues, inhibits bone resorption, and alters skeletal architecture through direct and indirect effects on a multiplicity of cells involved in skeletal adaptation. MAT is less well studied due to the lack of reproducible quantification techniques. In recent work, osmium-based 3D quantification shows a robust response of MAT to both dietary and exercise intervention in that MAT is elevated in response to high-fat diet and can be suppressed following daily exercise. Exercise-induced bone formation correlates with suppression of MAT, such that exercise effects might be due to either calorie expenditure from this depot or from mechanical biasing of MSC lineage away from fat and toward bone, or a combination thereof. Following treatment with the anti-diabetes drug rosiglitazone - a PPARγ-agonist known to increase MAT and fracture risk - mice demonstrate a fivefold higher femur MAT volume compared to the controls. In addition to preventing MAT accumulation in control mice, exercise intervention significantly lowers MAT accumulation in rosiglitazone-treated mice. Importantly, exercise induction of trabecular bone volume is unhindered by rosiglitazone. Thus, despite rosiglitazone augmentation of MAT, exercise significantly suppresses MAT volume and induces bone formation. That exercise can both suppress MAT volume and increase bone quantity, notwithstanding the skeletal harm induced by rosiglitazone, underscores exercise as a powerful regulator of bone remodeling, encouraging marrow stem cells toward the osteogenic lineage to fulfill an adaptive need for bone formation. Thus, exercise represents an effective strategy to mitigate the deleterious effects of overeating and iatrogenic etiologies on bone and fat.
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Affiliation(s)
- Gabriel M. Pagnotti
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Maya Styner
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
- *Correspondence: Maya Styner,
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19
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Morton TL, Galior K, McGrath C, Wu X, Uzer G, Uzer GB, Sen B, Xie Z, Tyson D, Rubin J, Styner M. Exercise Increases and Browns Muscle Lipid in High-Fat Diet-Fed Mice. Front Endocrinol (Lausanne) 2016; 7:80. [PMID: 27445983 PMCID: PMC4928595 DOI: 10.3389/fendo.2016.00080] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 06/20/2016] [Indexed: 12/25/2022] Open
Abstract
Muscle lipid increases with high-fat feeding and diabetes. In trained athletes, increased muscle lipid is not associated with insulin resistance, a phenomenon known as the athlete's paradox. To understand if exercise altered the phenotype of muscle lipid, female C57BL/6 mice fed CTL or high-fat diet (HFD for 6 or 18 weeks) were further divided into sedentary or exercising groups (CTL-E or HFD-E) with voluntary access to running wheels for the last 6 weeks of experiments, running 6 h/night. Diet did not affect running time or distance. HFD mice weighed more than CTL after 18 weeks (p < 0.01). Quadriceps muscle TG was increased in running animals and in sedentary mice fed HFD for 18 weeks (p < 0.05). In exercised animals, markers of fat, Plin1, aP2, FSP27, and Fasn, were increased significantly in HFD groups. Ucp1 and Pgc1a, markers for brown fat, increased with exercise in the setting of high fat feeding. Fndc5, which encodes irisin, and CytC were sensitive to exercise regardless of diet. Plin5 was increased with HFD and unaffected by exercise; the respiratory exchange ratio was 15% lower in the 18-week HFD group compared with CTL (p < 0.001) and 10% lower in 18 weeks HFD-E compared with CTL-E (p < 0.001). Increased Ucp1 and Pgc1a in exercised muscle of running mice suggests that a beige/brown fat phenotype develops, which differs from the fat phenotype that induces insulin resistance in high fat feeding. This suggests that increased muscle lipid may develop a "brown" phenotype in the setting of endurance exercise training, a shift that is further promoted by HFD.
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Affiliation(s)
- Tiffany L. Morton
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kornelia Galior
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Cody McGrath
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Xin Wu
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Gunes Uzer
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Guniz Bas Uzer
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Buer Sen
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Zhihui Xie
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - David Tyson
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Janet Rubin
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Maya Styner
- Department of Medicine, Division of Endocrinology and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- *Correspondence: Maya Styner,
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20
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Poulos SP, Dodson MV, Culver MF, Hausman GJ. The increasingly complex regulation of adipocyte differentiation. Exp Biol Med (Maywood) 2015; 241:449-56. [PMID: 26645953 DOI: 10.1177/1535370215619041] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 10/29/2015] [Indexed: 01/31/2023] Open
Abstract
Adipose (AD) tissue development and function relies on the ability of adipocytes to proliferate and differentiate into lipid-containing cells that also have endocrine function. Research suggests that certain conditions can induce AD tissue stem cells to differentiate into various cell types and that the microenvironment of the cell, including the extracellular matrix (ECM), is essential in maintaining cell and tissue function. This review provides an overview of factors involved in the proliferation and differentiation of adipocytes. A brief review of the numerous factors that influence PPARγ, the transcription factor thought to be the master regulator of adipocyte differentiation, provides context of established pathways that regulate adipogenesis. Thought provoking findings from research with hypoxia that is supported by earlier research that vascular development is related to adipogenesis are reviewed. Finally, our understanding of the critical role of the ECM and environment in adipogenesis is discussed and compared with studies that suggest that adipocytes may dedifferentiate and can convert into other cell types.
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Affiliation(s)
| | - Michael V Dodson
- Department of Animal Science, Washington State University, Pullman, WA 99164, USA
| | | | - Gary J Hausman
- Animal and Dairy Science Department, University of Georgia, Athens, GA 30602, USA
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21
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Li R, Liang L, Dou Y, Huang Z, Mo H, Wang Y, Yu B. Mechanical stretch inhibits mesenchymal stem cell adipogenic differentiation through TGFβ1/Smad2 signaling. J Biomech 2015; 48:3665-71. [PMID: 26341460 DOI: 10.1016/j.jbiomech.2015.08.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 08/10/2015] [Accepted: 08/13/2015] [Indexed: 12/28/2022]
Abstract
Mesenchymal stem cells (MSCs) are the common precursors of several functionally disparate cell lineages. A plethora of chemical and physical stimuli contribute to lineage decisions and guidance, including mechanical stretch concomitant with physical movement. Here, we examined how stretch regulates MSC differentiation into adipocytes and the intracellular signaling pathways involved. MSCs were cultured under adipogenic conditions and divided into a control and an experimental group. Cultures in the experimental group were subjected to a sinusoidal stretch regimen delivered via flexible culture bottoms (5% magnitude, 10 times per min, 6h/day, 3 or 5 days). Expression levels of the adipocyte markers PPARγ-2, adiponectin, and C/EBPα were measured as indices of differentiation. Compared to controls, MSCs exposed to mechanical stretch exhibited downregulated PPARγ-2, adiponectin, and C/EBPα mRNA expression. Alternatively, stretch upregulated phosphorylation of Smad2. This stretch-induced increase in Smad2 phosphorylation was suppressed by pretreatment with the TGFβ1/Smad2 pathway antagonist SB-431542. Pretreatment with the TGFβ1/Smad2 signaling agonist TGFβ1 facilitated the inhibitory effect of stretch on the expression levels of PPARγ-2, adiponectin, and C/EBPα proteins, while pretreatment with SB-431542 reversed the inhibitory effects of subsequent stretch on the expression levels of these markers. These results strongly suggest that the anti-adipogenic effects of mechanical stretch on MSCs are mediated, at least in part, by activation of the TGFβ1/Smad2 signaling pathway.
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Affiliation(s)
- Runguang Li
- Department of Orthopedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Huiqiao Department, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Liang Liang
- Department of Orthopedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Yonggang Dou
- Department of Orthopedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Zeping Huang
- Department of Orthopedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Huiting Mo
- Department of Orthopedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Yaning Wang
- Department of Orthopedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Bin Yu
- Department of Orthopedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
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22
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Styner M, Pagnotti GM, Galior K, Wu X, Thompson WR, Uzer G, Sen B, Xie Z, Horowitz MC, Styner MA, Rubin C, Rubin J. Exercise Regulation of Marrow Fat in the Setting of PPARγ Agonist Treatment in Female C57BL/6 Mice. Endocrinology 2015; 156:2753-61. [PMID: 26052898 PMCID: PMC4511140 DOI: 10.1210/en.2015-1213] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The contribution of marrow adipose tissue (MAT) to skeletal fragility is poorly understood. Peroxisome proliferator-activated receptor (PPAR)γ agonists, associated with increased fractures in diabetic patients, increase MAT. Here, we asked whether exercise could limit the MAT accrual and increase bone formation in the setting of PPARγ agonist treatment. Eight-week-old female C57BL/6 mice were treated with 20-mg/kg · d rosiglitazone (Rosi) and compared with control (CTL) animals. Exercise groups ran 12 km/d when provided access to running wheels (CTL exercise [CTL-E], Rosi-E). After 6 weeks, femoral MAT (volume of lipid binder osmium) and tibial bone morphology were assessed by microcomputer tomography. Rosi was associated with 40% higher femur MAT volume compared with CTL (P < .0001). Exercise suppressed MAT volume by half in CTL-E mice compared with CTL (P < .01) and 19% in Rosi-E compared with Rosi (P < .0001). Rosi treatment increased fat markers perilipin and fatty acid synthase mRNA by 4-fold (P < .01). Exercise was associated with increased uncoupling protein 1 mRNA expression in both CTL-E and Rosi-E groups (P < .05), suggestive of increased brown fat. Rosi increased cortical porosity (P < .0001) but did not significantly impact trabecular or cortical bone quantity. Importantly, exercise induction of trabecular bone volume was not prevented by Rosi (CTL-E 21% > CTL, P < .05; Rosi-E 26% > Rosi, P < .01). In summary, despite the Rosi induction of MAT extending well into the femoral diaphysis, exercise was able to significantly suppress MAT volume and induce bone formation. Our results suggest that the impact of PPARγ agonists on bone and marrow health can be partially mitigated by exercise.
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Affiliation(s)
- Maya Styner
- Department of Medicine (M.S., K.G., X.W., G.U., B.S., Z.X., J.R.), University of North Carolina, Chapel Hill, North Carolina; Department of Physical Therapy (W.R.T.), Indiana University, Indianapolis, Indiana; Department of Computer Science (M.A.S.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry (M.A.S.), Image Analysis, University of North Carolina, Chapel Hill, North Carolina; Department of Biomedical Engineering (G.M.P., C.R.), Stony Brook University, Stony Brook, New York; and Department of Orthopedics and Rehabilitation (M.C.H.), Yale University, New Haven, Connecticut
| | - Gabriel M Pagnotti
- Department of Medicine (M.S., K.G., X.W., G.U., B.S., Z.X., J.R.), University of North Carolina, Chapel Hill, North Carolina; Department of Physical Therapy (W.R.T.), Indiana University, Indianapolis, Indiana; Department of Computer Science (M.A.S.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry (M.A.S.), Image Analysis, University of North Carolina, Chapel Hill, North Carolina; Department of Biomedical Engineering (G.M.P., C.R.), Stony Brook University, Stony Brook, New York; and Department of Orthopedics and Rehabilitation (M.C.H.), Yale University, New Haven, Connecticut
| | - Kornelia Galior
- Department of Medicine (M.S., K.G., X.W., G.U., B.S., Z.X., J.R.), University of North Carolina, Chapel Hill, North Carolina; Department of Physical Therapy (W.R.T.), Indiana University, Indianapolis, Indiana; Department of Computer Science (M.A.S.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry (M.A.S.), Image Analysis, University of North Carolina, Chapel Hill, North Carolina; Department of Biomedical Engineering (G.M.P., C.R.), Stony Brook University, Stony Brook, New York; and Department of Orthopedics and Rehabilitation (M.C.H.), Yale University, New Haven, Connecticut
| | - Xin Wu
- Department of Medicine (M.S., K.G., X.W., G.U., B.S., Z.X., J.R.), University of North Carolina, Chapel Hill, North Carolina; Department of Physical Therapy (W.R.T.), Indiana University, Indianapolis, Indiana; Department of Computer Science (M.A.S.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry (M.A.S.), Image Analysis, University of North Carolina, Chapel Hill, North Carolina; Department of Biomedical Engineering (G.M.P., C.R.), Stony Brook University, Stony Brook, New York; and Department of Orthopedics and Rehabilitation (M.C.H.), Yale University, New Haven, Connecticut
| | - William R Thompson
- Department of Medicine (M.S., K.G., X.W., G.U., B.S., Z.X., J.R.), University of North Carolina, Chapel Hill, North Carolina; Department of Physical Therapy (W.R.T.), Indiana University, Indianapolis, Indiana; Department of Computer Science (M.A.S.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry (M.A.S.), Image Analysis, University of North Carolina, Chapel Hill, North Carolina; Department of Biomedical Engineering (G.M.P., C.R.), Stony Brook University, Stony Brook, New York; and Department of Orthopedics and Rehabilitation (M.C.H.), Yale University, New Haven, Connecticut
| | - Gunes Uzer
- Department of Medicine (M.S., K.G., X.W., G.U., B.S., Z.X., J.R.), University of North Carolina, Chapel Hill, North Carolina; Department of Physical Therapy (W.R.T.), Indiana University, Indianapolis, Indiana; Department of Computer Science (M.A.S.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry (M.A.S.), Image Analysis, University of North Carolina, Chapel Hill, North Carolina; Department of Biomedical Engineering (G.M.P., C.R.), Stony Brook University, Stony Brook, New York; and Department of Orthopedics and Rehabilitation (M.C.H.), Yale University, New Haven, Connecticut
| | - Buer Sen
- Department of Medicine (M.S., K.G., X.W., G.U., B.S., Z.X., J.R.), University of North Carolina, Chapel Hill, North Carolina; Department of Physical Therapy (W.R.T.), Indiana University, Indianapolis, Indiana; Department of Computer Science (M.A.S.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry (M.A.S.), Image Analysis, University of North Carolina, Chapel Hill, North Carolina; Department of Biomedical Engineering (G.M.P., C.R.), Stony Brook University, Stony Brook, New York; and Department of Orthopedics and Rehabilitation (M.C.H.), Yale University, New Haven, Connecticut
| | - Zhihui Xie
- Department of Medicine (M.S., K.G., X.W., G.U., B.S., Z.X., J.R.), University of North Carolina, Chapel Hill, North Carolina; Department of Physical Therapy (W.R.T.), Indiana University, Indianapolis, Indiana; Department of Computer Science (M.A.S.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry (M.A.S.), Image Analysis, University of North Carolina, Chapel Hill, North Carolina; Department of Biomedical Engineering (G.M.P., C.R.), Stony Brook University, Stony Brook, New York; and Department of Orthopedics and Rehabilitation (M.C.H.), Yale University, New Haven, Connecticut
| | - Mark C Horowitz
- Department of Medicine (M.S., K.G., X.W., G.U., B.S., Z.X., J.R.), University of North Carolina, Chapel Hill, North Carolina; Department of Physical Therapy (W.R.T.), Indiana University, Indianapolis, Indiana; Department of Computer Science (M.A.S.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry (M.A.S.), Image Analysis, University of North Carolina, Chapel Hill, North Carolina; Department of Biomedical Engineering (G.M.P., C.R.), Stony Brook University, Stony Brook, New York; and Department of Orthopedics and Rehabilitation (M.C.H.), Yale University, New Haven, Connecticut
| | - Martin A Styner
- Department of Medicine (M.S., K.G., X.W., G.U., B.S., Z.X., J.R.), University of North Carolina, Chapel Hill, North Carolina; Department of Physical Therapy (W.R.T.), Indiana University, Indianapolis, Indiana; Department of Computer Science (M.A.S.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry (M.A.S.), Image Analysis, University of North Carolina, Chapel Hill, North Carolina; Department of Biomedical Engineering (G.M.P., C.R.), Stony Brook University, Stony Brook, New York; and Department of Orthopedics and Rehabilitation (M.C.H.), Yale University, New Haven, Connecticut
| | - Clinton Rubin
- Department of Medicine (M.S., K.G., X.W., G.U., B.S., Z.X., J.R.), University of North Carolina, Chapel Hill, North Carolina; Department of Physical Therapy (W.R.T.), Indiana University, Indianapolis, Indiana; Department of Computer Science (M.A.S.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry (M.A.S.), Image Analysis, University of North Carolina, Chapel Hill, North Carolina; Department of Biomedical Engineering (G.M.P., C.R.), Stony Brook University, Stony Brook, New York; and Department of Orthopedics and Rehabilitation (M.C.H.), Yale University, New Haven, Connecticut
| | - Janet Rubin
- Department of Medicine (M.S., K.G., X.W., G.U., B.S., Z.X., J.R.), University of North Carolina, Chapel Hill, North Carolina; Department of Physical Therapy (W.R.T.), Indiana University, Indianapolis, Indiana; Department of Computer Science (M.A.S.), University of North Carolina, Chapel Hill, North Carolina; Department of Psychiatry (M.A.S.), Image Analysis, University of North Carolina, Chapel Hill, North Carolina; Department of Biomedical Engineering (G.M.P., C.R.), Stony Brook University, Stony Brook, New York; and Department of Orthopedics and Rehabilitation (M.C.H.), Yale University, New Haven, Connecticut
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23
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Thompson WR, Keller BV, Davis ML, Dahners LE, Weinhold PS. Low-Magnitude, High-Frequency Vibration Fails to Accelerate Ligament Healing but Stimulates Collagen Synthesis in the Achilles Tendon. Orthop J Sports Med 2015; 3. [PMID: 26086026 PMCID: PMC4467027 DOI: 10.1177/2325967115585783] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Background: Low-magnitude, high-frequency vibration accelerates fracture and wound healing and prevents disuse atrophy in musculoskeletal tissues. Purpose: To investigate the role of low-magnitude, high-frequency vibration as a treatment to accelerate healing of an acute ligament injury and to examine gene expression in the intact Achilles tendon of the injured limb after low-magnitude, high-frequency vibration. Study Design: Controlled laboratory study. Methods: Complete surgical transection of the medial collateral ligament (MCL) was performed in 32 Sprague-Dawley rats, divided into control and low-magnitude, high-frequency vibration groups. Low-magnitude, high-frequency vibration started on postoperative day 2, and rats received vibration for 30 minutes a day for 12 days. All rats were sacrificed 2 weeks after the operation, and their intact and injured MCLs were biomechanically tested or used for histological analysis. Intact Achilles tendons from the injured limb were evaluated for differences in gene expression. Results: Mechanical testing revealed no differences in the ultimate tensile load or the structural stiffness between the control and vibration groups for either the injured or intact MCL. Vibration exposure increased gene expression of collagen 1 alpha (3-fold), interleukin 6 (7-fold), cyclooxygenase 2 (5-fold), and bone morphogenetic protein 12 (4-fold) in the intact Achilles tendon when compared with control tendons (P < .05). Conclusion: While no differences were observed in the mechanical or histological properties of the fully transected MCL after low-magnitude, high-frequency vibration treatment, significant enhancements in gene expression were observed in the intact Achilles tendon. These included collagen, several inflammatory cytokines, and growth factors critical for tendons. Clinical Relevance: As low-magnitude, high-frequency vibration had no negative effects on ligament healing, vibration therapy may be a useful tool to accelerate healing of other tissues (bone) in multitrauma injuries without inhibiting ligament healing. Additionally, the enhanced gene expression in response to low-magnitude, high-frequency vibration in the intact Achilles tendon suggests the need to further study its potential to accelerate tendon healing in partial injury or repair models.
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Affiliation(s)
- William R Thompson
- Department of Physical Therapy, School of Health and Rehabilitation Sciences, Indiana University, Indianapolis, Indiana, USA
| | - Benjamin V Keller
- Department of Orthopedics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Matthew L Davis
- Department of Orthopedics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Laurence E Dahners
- Department of Orthopedics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Paul S Weinhold
- Department of Orthopedics, University of North Carolina, Chapel Hill, North Carolina, USA
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24
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Castañeda P, Muñoz M, García-Rojo G, Ulloa JL, Bravo JA, Márquez R, García-Pérez MA, Arancibia D, Araneda K, Rojas PS, Mondaca-Ruff D, Díaz-Véliz G, Mora S, Aliaga E, Fiedler JL. Association of N-cadherin levels and downstream effectors of Rho GTPases with dendritic spine loss induced by chronic stress in rat hippocampal neurons. J Neurosci Res 2015; 93:1476-91. [PMID: 26010004 DOI: 10.1002/jnr.23602] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 05/03/2015] [Accepted: 05/04/2015] [Indexed: 12/24/2022]
Abstract
Chronic stress promotes cognitive impairment and dendritic spine loss in hippocampal neurons. In this animal model of depression, spine loss probably involves a weakening of the interaction between pre- and postsynaptic cell adhesion molecules, such as N-cadherin, followed by disruption of the cytoskeleton. N-cadherin, in concert with catenin, stabilizes the cytoskeleton through Rho-family GTPases. Via their effector LIM kinase (LIMK), RhoA and ras-related C3 botulinum toxin substrate 1 (RAC) GTPases phosphorylate and inhibit cofilin, an actin-depolymerizing molecule, favoring spine growth. Additionally, RhoA, through Rho kinase (ROCK), inactivates myosin phosphatase through phosphorylation of the myosin-binding subunit (MYPT1), producing actomyosin contraction and probable spine loss. Some micro-RNAs negatively control the translation of specific mRNAs involved in Rho GTPase signaling. For example, miR-138 indirectly activates RhoA, and miR-134 reduces LIMK1 levels, resulting in spine shrinkage; in contrast, miR-132 activates RAC1, promoting spine formation. We evaluated whether N-cadherin/β-catenin and Rho signaling is sensitive to chronic restraint stress. Stressed rats exhibit anhedonia, impaired associative learning, and immobility in the forced swim test and reduction in N-cadherin levels but not β-catenin in the hippocampus. We observed a reduction in spine number in the apical dendrites of CA1 pyramidal neurons, with no effect on the levels of miR-132 or miR-134. Although the stress did not modify the RAC-LIMK-cofilin signaling pathway, we observed increased phospho-MYPT1 levels, probably mediated by RhoA-ROCK activation. Furthermore, chronic stress raises the levels of miR-138 in accordance with the observed activation of the RhoA-ROCK pathway. Our findings suggest that a dysregulation of RhoA-ROCK activity by chronic stress could potentially underlie spine loss in hippocampal neurons.
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Affiliation(s)
- Patricia Castañeda
- Department of Biology, Faculty of Sciences, Universidad Metropolitana de Ciencias de la Educación, Santiago, Chile
| | - Mauricio Muñoz
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - Gonzalo García-Rojo
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - José L Ulloa
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - Javier A Bravo
- Grupo de NeuroGastroBioquímica, Laboratorio de Química Biológica, Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Ruth Márquez
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - M Alexandra García-Pérez
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - Damaris Arancibia
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - Karina Araneda
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - Paulina S Rojas
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - David Mondaca-Ruff
- Graduate Student PhD Program, Department of Pharmacology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - Gabriela Díaz-Véliz
- Laboratorio Farmacología del Comportamiento, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Sergio Mora
- Laboratorio Farmacología del Comportamiento, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Esteban Aliaga
- Escuela de Kinesiología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Jenny L Fiedler
- Laboratory of Neuroplasticity and Neurogenetics, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
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25
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Obiorah IE, Jordan VC. Differences in the rate of oestrogen-induced apoptosis in breast cancer by oestradiol and the triphenylethylene bisphenol. Br J Pharmacol 2015; 171:4062-72. [PMID: 24819221 DOI: 10.1111/bph.12762] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 04/16/2014] [Accepted: 04/25/2014] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND AND PURPOSE Triphenylethylene (TPE)-like compounds were the first agents to be used in the treatment of metastatic breast cancer in postmenopausal women. Although structurally related to the anti-oestrogen, 4-hydroxytamoxifen, TPEs possess oestrogenic properties in fully oestrogenized breast cancer cells but do not induce apoptosis with short-term treatment in long-term oestrogen-deprived breast cancer cells. This study determined the differential effects of bisphenol, a TPE, on growth and apoptosis based on the modulation of the shape of the ligand-oestrogen receptor complex. EXPERIMENTAL APPROACH Apoptotic flow cytometric studies were used to evaluate apoptosis over time. Proliferation of the breast cancer cells was assessed using DNA quantification and cell cycle analysis. Real-time PCR was performed to quantify mRNA levels of apoptotic genes. Regulation of cell cycle and apoptotic genes was determined using PCR-based arrays. KEY RESULTS Bisphenol induced an up-regulation of cell cycle genes similar to those induced by 17β oestradiol (E2 ). Unlike the changes induced by E2 that occur after 24 h, the apoptosis evoked by bisphenol occurred after 4 days, with quantifiable apoptotic changes noted at 6 days. A prolonged up-regulation of endoplasmic reticulum stress and inflammatory stress response genes was observed with subsequent activation of apoptosis-related genes in the second week of treatment with bisphenol. CONCLUSIONS AND IMPLICATIONS The bisphenol: ERα complex induces delayed biological effects on the growth and apoptosis of breast cancer cells. Both the shape of the complex and the duration of treatment control the initiation of apoptosis.
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Affiliation(s)
- I E Obiorah
- Tumor Biology Training Program, Georgetown University, Washington, DC, USA
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26
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Baker N, Boyette LB, Tuan RS. Characterization of bone marrow-derived mesenchymal stem cells in aging. Bone 2015; 70:37-47. [PMID: 25445445 DOI: 10.1016/j.bone.2014.10.014] [Citation(s) in RCA: 198] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 10/16/2014] [Accepted: 10/22/2014] [Indexed: 12/17/2022]
Abstract
Adult mesenchymal stem cells are a resource for autologous and allogeneic cell therapies for immune-modulation and regenerative medicine. However, patients most in need of such therapies are often of advanced age. Therefore, the effects of the aged milieu on these cells and their intrinsic aging in vivo are important considerations. Furthermore, these cells may require expansion in vitro before use as well as for future research. Their aging in vitro is thus also an important consideration. Here, we focus on bone marrow mesenchymal stem cells (BMSCs), which are unique compared to other stem cells due to their support of hematopoietic cells in addition to contributing to bone formation. BMSCs may be sensitive to age-related diseases and could perpetuate degenerative diseases in which bone remodeling is a contributory factor. Here, we review (1) the characterization of BMSCs, (2) the characterization of in vivo-aged BMSCs, (3) the characterization of in vitro-aged BMSCs, and (4) potential approaches to optimize the performance of aged BMSCs. This article is part of a Special Issue entitled "Stem Cells and Bone".
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Affiliation(s)
- Natasha Baker
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Lisa B Boyette
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Rocky S Tuan
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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27
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Styner M, Thompson WR, Galior K, Uzer G, Wu X, Kadari S, Case N, Xie Z, Sen B, Romaine A, Pagnotti GM, Rubin CT, Styner MA, Horowitz MC, Rubin J. Bone marrow fat accumulation accelerated by high fat diet is suppressed by exercise. Bone 2014; 64:39-46. [PMID: 24709686 PMCID: PMC4041820 DOI: 10.1016/j.bone.2014.03.044] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 02/17/2014] [Accepted: 03/25/2014] [Indexed: 01/14/2023]
Abstract
Marrow adipose tissue (MAT), associated with skeletal fragility and hematologic insufficiency, remains poorly understood and difficult to quantify. We tested the response of MAT to high fat diet (HFD) and exercise using a novel volumetric analysis, and compared it to measures of bone quantity. We hypothesized that HFD would increase MAT and diminish bone quantity, while exercise would slow MAT acquisition and promote bone formation. Eight week-old female C57BL/6 mice were fed a regular (RD) or HFD, and exercise groups were provided voluntary access to running wheels (RD-E, HFD-E). Femoral MAT was assessed by μCT (lipid binder osmium) using a semi-automated approach employing rigid co-alignment, regional bone masks and was normalized for total femoral volume (TV) of the bone compartment. MAT was 2.6-fold higher in HFD relative to RD mice. Exercise suppressed MAT in RD-E mice by more than half compared with RD. Running similarly inhibited MAT acquisition in HFD mice. Exercise significantly increased bone quantity in both diet groups. Thus, HFD caused significant accumulation of MAT; importantly running exercise limited MAT acquisition while promoting bone formation during both diets. That MAT is exquisitely responsive to diet and exercise, and its regulation by exercise appears to be inversely proportional to effects on exercise induced bone formation, is relevant for an aging and sedentary population.
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Affiliation(s)
- Maya Styner
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA.
| | - William R Thompson
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Kornelia Galior
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Gunes Uzer
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Xin Wu
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Sanjay Kadari
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Natasha Case
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Zhihui Xie
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Buer Sen
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Andrew Romaine
- Department of Psychiatry and Computer Science, University of North Carolina, Chapel Hill, NC, USA
| | - Gabriel M Pagnotti
- Department of Biomedical Engineering, State University of New York, Stony Brook, NY, USA
| | - Clinton T Rubin
- Department of Biomedical Engineering, State University of New York, Stony Brook, NY, USA
| | - Martin A Styner
- Department of Computer Science, University of North Carolina, Chapel Hill, NC, USA; Department of Psychiatry and Computer Science, University of North Carolina, Chapel Hill, NC, USA
| | - Mark C Horowitz
- Department of Orthopedics and Rehabilitation, Yale University, New Haven, CT, USA
| | - Janet Rubin
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
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28
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Obiorah IE, Fan P, Jordan VC. Breast cancer cell apoptosis with phytoestrogens is dependent on an estrogen-deprived state. Cancer Prev Res (Phila) 2014; 7:939-49. [PMID: 24894196 DOI: 10.1158/1940-6207.capr-14-0061] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Phytoestrogens have been investigated as natural alternatives to hormone replacement therapy and their potential as chemopreventive agents. We investigated the effects of equol, genistein, and coumestrol on cell growth in fully estrogenized MCF7 cells, simulating the perimenopausal state, and long-term estrogen-deprived MCF7:5C cells, which simulate the postmenopausal state of a woman after years of estrogen deprivation, and compared the effects with that of steroidal estrogens: 17β estradiol (E2) and equilin present in conjugated equine estrogen. Steroidal and phytoestrogens induce proliferation of MCF7 cells at physiologic concentrations but inhibit the growth and induce apoptosis of MCF7:5C cells. Although steroidal and phytoestrogens induce estrogen-responsive genes, their antiproliferative and apoptotic effects are mediated through the estrogen receptor. Knockdown of ERα using siRNA blocks all estrogen-induced apoptosis and growth inhibition. Phytoestrogens induce endoplasmic reticulum stress and inflammatory response stress-related genes in a comparable manner as the steroidal estrogens. Inhibition of inflammation using dexamethasone blocked both steroidal- and phytoestrogen-induced apoptosis and growth inhibition as well as their ability to induce apoptotic genes. Together, this suggests that phytoestrogens can potentially be used as chemopreventive agents in older postmenopausal women but caution should be exercised when used in conjunction with steroidal anti-inflammatory agents due to their antiapoptotic effects.
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Affiliation(s)
- Ifeyinwa E Obiorah
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC
| | - Ping Fan
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC
| | - V Craig Jordan
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC
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29
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Mechanical stress stimulates the osteo/odontoblastic differentiation of human stem cells from apical papilla via erk 1/2 and JNK MAPK pathways. BIOMED RESEARCH INTERNATIONAL 2014; 2014:494378. [PMID: 24826377 PMCID: PMC4009119 DOI: 10.1155/2014/494378] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 03/04/2014] [Accepted: 03/04/2014] [Indexed: 01/09/2023]
Abstract
BACKGROUND INFORMATION Stem cells from apical papilla (SCAPs) are a potent candidate for the apexogenesis/apexification due to their multiple differentiation capacity. During the orthodontic treatment of developing teeth, SCAPs in vivo are usually subjected to the cyclic stress induced by compression forces. However, it remains unclear whether mechanical stress can affect the proliferation and differentiation of human SCAPs. RESULTS Human SCAPs were isolated and stimulated by 200 g mechanical stimuli for 30 min and their proliferation and differentiation capacity were evaluated in vitro at different time points. MTT and FCM results demonstrated that cell proliferation was enhanced, while TEM findings showed the morphological and ultrastructural changes in stress-treated SCAPs. ALP activity and mineralization capacity of stress-treated SCAPs were upregulated . In the meantime, higher odontogenic and osteogenic differentiation were found in stress-treated SCAPs by real-time RT-PCR and Western blot, as indicated by the expression of related markers at both mRNA and protein levels. Moreover, the protein expressions of pJNK and pERK MAPK pathways were upregulated. CONCLUSION Together, these findings suggest that mechanical stress is an important factor affecting the proliferation and differentiation of SCAPs via the activation of ERK and JNK signaling pathway.
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