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Zhu M, Zeiss C, Hamrick MW, Weinstein RS, Sun BH, Brotto M, Liu X, Siu E, Huttner A, Tommasini S, Simpson C, Insogna K. Mitofusin 2 plays a critical role in maintaining the functional integrity of the neuromuscular-skeletal axis. Bone 2024; 184:117086. [PMID: 38552893 DOI: 10.1016/j.bone.2024.117086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 03/22/2024] [Accepted: 03/23/2024] [Indexed: 05/12/2024]
Abstract
PURPOSE Mitofusin 2 (Mfn2) is one of two mitofusins involved in regulating mitochondrial size, shape and function, including mitophagy, an important cellular mechanism to limit oxidative stress. Reduced expression of Mfn2 has been associated with impaired osteoblast differentiation and function and a reduction in the number of viable osteocytes in bone. We hypothesized that the genetic absence of Mfn2 in these cells would increase their susceptibility to aging-associated metabolic stress, leading to a progressive impairment in skeletal homeostasis over time. METHODS Mfn2 was selectively deleted in vivo at three different stages of osteoblast lineage commitment by crossing mice in which the Mfn2 gene was floxed with transgenic mice expressing Cre under the control of the promoter for Osterix (OSX), collagen1a1, or DMP1 (Dentin Matrix Acidic Phosphoprotein 1). RESULTS Mice in which Mfn2 was deleted using DMP1-cre demonstrated a progressive and dramatic decline in bone mineral density (BMD) beginning at 10 weeks of age (n = 5 for each sex and each genotype from age 10 to 20 weeks). By 15 weeks, there was evidence for a functional decline in muscle performance as assessed using a rotarod apparatus (n = 3; 2 males/ 1 female for each genotype), accompanied by a decline in lean body mass. A marked reduction in trabecular bone mass was evident on bone histomorphometry, and biomechanical testing at 25 weeks (k/o: 2 male/1 female, control 2 male/2 female) revealed severely impaired femur strength. Extensive regional myofiber atrophy and degeneration was observed on skeletal muscle histology. Electron microscopy showed progressive disruption of cellular architecture, with disorganized sarcomeres and a bloated mitochondrial reticulum. There was also evidence of neurodegeneration within the ventral horn and roots of the lumbar spinal cord, which was accompanied by myelin loss and myofiber atrophy. Deletion of Mfn2 using OSX-cre or Col1a1-cre did not result in a musculoskeletal phenotype. Where possible, male and female animals were analyzed separately, but small numbers of animals in each group limited statistical power. For other outcomes, where sex was not considered, small sample sizes might still limit the strength of the observation. CONCLUSION Despite known functional overlap of Mfn1 and Mfn2 in some tissues, and their co-expression in bone, muscle and spinal cord, deletion of Mfn2 using the 8 kB DMP1 promoter uncovered an important non-redundant role for Mfn2 in maintaining the neuromuscular/bone axis.
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Affiliation(s)
- Meiling Zhu
- Yale School of Medicine, Section of Endocrinology, New Haven, CT, USA
| | - Caroline Zeiss
- Yale School of Medicine, Section of Comparative Medicine, New Haven, CT, USA
| | - Mark W Hamrick
- Department of Orthopaedic Surgery, Institute of Molecular Medicine & Genetics, Medical College of Georgia, Augusta, GA, USA
| | - Robert S Weinstein
- Division of Endocrinology, Metabolic Bone Diseases, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Ben-Hua Sun
- Yale School of Medicine, Section of Endocrinology, New Haven, CT, USA
| | - Marco Brotto
- Bone-Muscle Research Center, College of Nursing & Health Innovation, University of Texas at Arlington, Arlington, TX, USA
| | - Xinran Liu
- Yale School of Medicine, Center for Cellular and Molecular Imaging, New Haven, CT, USA
| | - Edwin Siu
- Yale School of Medicine, Section of Endocrinology, New Haven, CT, USA
| | - Anita Huttner
- Yale School of Medicine, Department of Pathology, New Haven, CT, USA
| | - Steven Tommasini
- Yale School of Medicine, Department of Orthopaedics & Rehabilitation, New Haven, CT, USA
| | - Christine Simpson
- Yale School of Medicine, Section of Endocrinology, New Haven, CT, USA
| | - Karl Insogna
- Yale School of Medicine, Section of Endocrinology, New Haven, CT, USA.
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Xie WQ, He M, Yu DJ, Li HZ, Jin HF, Ji BZ, Yang G, Chen LL, Rahmati M, Li YS. Correlation study between bone metabolic markers, bone mineral density, and sarcopenia. J Endocrinol Invest 2024; 47:1559-1572. [PMID: 38097848 DOI: 10.1007/s40618-023-02252-8] [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: 08/01/2023] [Accepted: 11/19/2023] [Indexed: 02/21/2024]
Abstract
OBJECTIVE To investigate the correlation between bone metabolism markers, bone mineral density (BMD), and sarcopenia. METHODS A total of 331 consecutive patients aged ≥ 60 years who were hospitalized between November 2020 and December 2021 were enrolled. Participants were divided into sarcopenia and non-sarcopenia groups according to the Asian Working Group on Sarcopenia criteria (AWGS, 2019). The clinical data, bone metabolism markers (β-CTX, N-MID, and TP1NP), and BMD were compared between the two groups. RESULTS Age, β-CTX, and N-MID of the sarcopenia group were higher than those of the non-sarcopenia group (P < 0.05), but the BMD T values were lower than those of the non-sarcopenia group (P < 0.05). Binary logistic regression analysis showed that increased femoral neck BMD (FNBMD) was a protective factor for sarcopenia, while increased β-CTX was a risk factor. Pearson/Spearman correlation analysis showed that the diagnostic indices of sarcopenia were positively correlated with FNBMD and negatively correlated with β-CTX and N-MID. Multiple linear regression analysis revealed that BMI and FNBMD significantly positively affected muscle strength and appendicular skeletal muscle mass (ASM). The FNBMD significantly positively affected physical performance, while β-CTX significantly negatively affected muscle strength, ASM, and physical performance. CONCLUSION Increased FNBMD may be a protective factor against sarcopenia, and increased β-CTX may be a risk factor. The FNBMD significantly positively affected the diagnostic indices of sarcopenia, while β-CTX significantly negatively affected them. BMD and bone metabolism marker levels may be considered in early screening for sarcopenia.
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Affiliation(s)
- W Q Xie
- Deparment of Orthopedics, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - M He
- Deparment of Orthopedics, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - D J Yu
- Deparment of Orthopedics, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - H Z Li
- Deparment of Orthopedics, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - H F Jin
- Deparment of Orthopedics, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - B Z Ji
- Deparment of Orthopedics, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - G Yang
- Deparment of Orthopedics, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - L L Chen
- Hunan Key Laboratory for Bioanalysis of Complex Matrix Samples, Changsha, 410000, Hunan, China
| | - M Rahmati
- Department of Physical Education and Sport Sciences, Faculty of Literature and Human Sciences, Lorestan University, Khorramabad, Iran
- Department of Physical Education and Sport Sciences, Faculty of Literature and Humanities, Vali-E-Asr University of Rafsanjan, Rafsanjan, Iran
| | - Y S Li
- Deparment of Orthopedics, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
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Rahmati M, Haffner M, Lee MA, Leach JK, Saiz AM. The critical impact of traumatic muscle loss on fracture healing: Basic science and clinical aspects. J Orthop Res 2024; 42:249-258. [PMID: 37990953 DOI: 10.1002/jor.25746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/05/2023] [Accepted: 11/20/2023] [Indexed: 11/23/2023]
Abstract
Musculoskeletal trauma, specifically fractures, is a leading cause of patient morbidity and disability worldwide. In approximately 20% of cases with fracture and related traumatic muscle loss, bone healing is impaired leading to fracture nonunion. Over the past few years, several studies have demonstrated that bone and the surrounding muscle tissue interact not only anatomically and mechanically but also through biochemical pathways and mediators. Severe damage to the surrounding musculature at the fracture site causes an insufficiency in muscle-derived osteoprogenitor cells that are crucial for fracture healing. As an endocrine tissue, skeletal muscle produces many myokines that act on different bone cells, such as osteoblasts, osteoclasts, osteocytes, and mesenchymal stem cells. Investigating how muscle influences fracture healing at cellular, molecular, and hormonal levels provides translational therapeutic solutions to this clinical challenge. This review provides an overview about the contributions of surrounding muscle tissue in directing fracture healing. The focus of the review is on describing the interactions between bone and muscle in both healthy and fractured environments. We discuss current progress in identifying the bone-muscle molecular pathways and strategies to harness these pathways as cues for accelerating fracture healing. In addition, we review the existing challenges and research opportunities in the field.
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Affiliation(s)
- Maryam Rahmati
- Department of Orthopaedic Surgery, University of California, Davis, Sacramento, California, USA
| | - Max Haffner
- Department of Orthopaedic Surgery, University of California, Davis, Sacramento, California, USA
| | - Mark A Lee
- Department of Orthopaedic Surgery, University of California, Davis, Sacramento, California, USA
| | - Jonathan Kent Leach
- Department of Orthopaedic Surgery, University of California, Davis, Sacramento, California, USA
- Department of Biomedical Engineering, University of California, Davis, Davis, California, USA
| | - Augustine M Saiz
- Department of Orthopaedic Surgery, University of California, Davis, Sacramento, California, USA
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Yang J, Liu P, Wang S, Jiang T, Zhang Y, Liu W. Causal relationship between sarcopenia and osteoarthritis: a bi-directional two-sample mendelian randomized study. Eur J Med Res 2023; 28:327. [PMID: 37689698 PMCID: PMC10492359 DOI: 10.1186/s40001-023-01322-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 08/27/2023] [Indexed: 09/11/2023] Open
Abstract
BACKGROUND Previous studies have shown that osteoarthritis (OA) and sarcopenia (SP) are closely related to each other, but the causal relationships between them have not been established. The aim of this study was to investigate the causal associations between OA and SP via a bi-directional Mendelian randomization (MR) approach. METHODS A bi-directional two-sample MR was adopted to research the causal relationship between SP and OA. The instrumental variables for SP and four types of OA: KOA, HOA, total knee replacement (TKR) and total hip replacement (THR) were derived from published large genome-wide association studies (GWAS). The inverse variance weighted (IVW), MR-Egger and weighted median estimator (WME) methods were used to estimate bi-directional causal effects. RESULTS Low grip strength (GS) did not have a causal effect on four types of OA (KOA: OR = 1.205, 95% CI 0.837-1.734, p = 0.316; HOA: OR = 1.090, 95% CI 0.924-1.609, p = 0.307; TKR: OR = 1.190, 95% CI 1.084-1.307, p = 0.058; THR: OR = 1.035, 95% CI 0.792-1.353, p = 0.798), while appendicular lean mass (ALM) had a causal effect on four types of OA (KOA: OR = 1.104, 95% CI 1.041-1.171, p = 0.001; HOA: OR = 1.151, 95% CI 1.071-1.237, p < 0.001; TKR: OR = 1.114, 95% CI 1.007-1.232, p < 0.001; THR: OR = 1.203, 95% CI 1.099-1.316, p < 0.001). In the reverse direction, KOA or HOA did not have a significant causal effect on both GS and ALM (KOA-GS: OR = 1.077, 95% CI 0.886-1.309, p = 0.458; KOA-ALM: Beta = 0.004, p = 0.892; HOA-GS: OR = 1.038, 95% CI 0.981-1.099, p = 0.209; HOA-ALM: Beta = - 0.017, p = 0.196; TKR-GS: OR = 0.999, 95% CI 0.739-1.351, p = 0.997; TKR-ALM: Beta = 0.018, p = 0.501; THR-GS: OR = 1.037, 95% CI 0.978-1.101, p = 0.222; THR-ALM: Beta = - 0.023, p = 0.081). CONCLUSIONS The present study suggests that SP may have a causal effect on OA through changes in muscle composition rather than muscle strength, while little evidence was provided for the causal effect of OA on SP.
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Affiliation(s)
- Jiyong Yang
- The Fifth Clinical College of Guangzhou, University of Chinese Medicine, Guangzhou, China
| | - Peng Liu
- The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Shuai Wang
- The Fifth Clinical College of Guangzhou, University of Chinese Medicine, Guangzhou, China
| | - Tao Jiang
- Department of Orthopedics, Guangdong Second Traditional Chinese Medicine Hospital, Guangzhou, China
| | - Yilong Zhang
- The Fifth Clinical College of Guangzhou, University of Chinese Medicine, Guangzhou, China
| | - Wengang Liu
- Department of Orthopedics, Guangdong Second Traditional Chinese Medicine Hospital, Guangzhou, China.
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Liu M, Wang Y, Shi W, Yang C, Wang Q, Chen J, Li J, Chen B, Sun G. PCDH7 as the key gene related to the co-occurrence of sarcopenia and osteoporosis. Front Genet 2023; 14:1163162. [PMID: 37476411 PMCID: PMC10354703 DOI: 10.3389/fgene.2023.1163162] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 04/06/2023] [Indexed: 07/22/2023] Open
Abstract
Sarcopenia and osteoporosis, two degenerative diseases in older patients, have become severe health problems in aging societies. Muscles and bones, the most important components of the motor system, are derived from mesodermal and ectodermal mesenchymal stem cells. The adjacent anatomical relationship between them provides the basic conditions for mechanical and chemical signals, which may contribute to the co-occurrence of sarcopenia and osteoporosis. Identifying the potential common crosstalk genes between them may provide new insights for preventing and treating their development. In this study, DEG analysis, WGCNA, and machine learning algorithms were used to identify the key crosstalk genes of sarcopenia and osteoporosis; this was then validated using independent datasets and clinical samples. Finally, four crosstalk genes (ARHGEF10, PCDH7, CST6, and ROBO3) were identified, and mRNA expression and protein levels of PCDH7 in clinical samples from patients with sarcopenia, with osteoporosis, and with both sarcopenia and osteoporosis were found to be significantly higher than those from patients without sarcopenia or osteoporosis. PCDH7 seems to be a key gene related to the development of both sarcopenia and osteoporosis.
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Affiliation(s)
- Mingchong Liu
- Department of Traumatic Surgery, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yongheng Wang
- Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Wentao Shi
- Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Chensong Yang
- Department of Traumatic Surgery, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Qidong Wang
- Department of Traumatic Surgery, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Jingyao Chen
- Institute for Regenerative Medicine, Shanghai East Hospital, The Institute for Biomedical Engineering and Nano Science, Tongji University School of Medicine, Shanghai, China
| | - Jun Li
- Institute for Regenerative Medicine, Shanghai East Hospital, The Institute for Biomedical Engineering and Nano Science, Tongji University School of Medicine, Shanghai, China
| | - Bingdi Chen
- Institute for Regenerative Medicine, Shanghai East Hospital, The Institute for Biomedical Engineering and Nano Science, Tongji University School of Medicine, Shanghai, China
| | - Guixin Sun
- Department of Traumatic Surgery, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
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Zhao D, Wu J, Acosta FM, Xu H, Jiang JX. Connexin 43 hemichannels and prostaglandin E 2 release in anabolic function of the skeletal tissue to mechanical stimulation. Front Cell Dev Biol 2023; 11:1151838. [PMID: 37123401 PMCID: PMC10133519 DOI: 10.3389/fcell.2023.1151838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 04/05/2023] [Indexed: 05/02/2023] Open
Abstract
Bone adapts to changes in the physical environment by modulating remodeling through bone resorption and formation to maintain optimal bone mass. As the most abundant connexin subtype in bone tissue, connexin 43 (Cx43)-forming hemichannels are highly responsive to mechanical stimulation by permitting the exchange of small molecules (<1.2 kDa) between bone cells and the extracellular environment. Upon mechanical stimulation, Cx43 hemichannels facilitate the release of prostaglandins E2 (PGE2), a vital bone anabolic factor from osteocytes. Although most bone cells are involved in mechanosensing, osteocytes are the principal mechanosensitive cells, and PGE2 biosynthesis is greatly enhanced by mechanical stimulation. Mechanical stimulation-induced PGE2 released from osteocytic Cx43 hemichannels acts as autocrine effects that promote β-catenin nuclear accumulation, Cx43 expression, gap junction function, and protects osteocytes against glucocorticoid-induced osteoporosis in cultured osteocytes. In vivo, Cx43 hemichannels with PGE2 release promote bone formation and anabolism in response to mechanical loading. This review summarizes current in vitro and in vivo understanding of Cx43 hemichannels and extracellular PGE2 release, and their roles in bone function and mechanical responses. Cx43 hemichannels could be a significant potential new therapeutic target for treating bone loss and osteoporosis.
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Affiliation(s)
- Dezhi Zhao
- School of Medicine, Northwest University, Xi’an, China
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, United States
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, China
| | - Jiawei Wu
- School of Medicine, Northwest University, Xi’an, China
| | - Francisca M. Acosta
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, United States
| | - Huiyun Xu
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, China
| | - Jean X. Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, United States
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Abstract
Changes in bone architecture and metabolism with aging increase the likelihood of osteoporosis and fracture. Age-onset osteoporosis is multifactorial, with contributory extrinsic and intrinsic factors including certain medical problems, specific prescription drugs, estrogen loss, secondary hyperparathyroidism, microenvironmental and cellular alterations in bone tissue, and mechanical unloading or immobilization. At the histological level, there are changes in trabecular and cortical bone as well as marrow cellularity, lineage switching of mesenchymal stem cells to an adipogenic fate, inadequate transduction of signals during skeletal loading, and predisposition toward senescent cell accumulation with production of a senescence-associated secretory phenotype. Cumulatively, these changes result in bone remodeling abnormalities that over time cause net bone loss typically seen in older adults. Age-related osteoporosis is a geriatric syndrome due to the multiple etiologies that converge upon the skeleton to produce the ultimate phenotypic changes that manifest as bone fragility. Bone tissue is dynamic but with tendencies toward poor osteoblastic bone formation and relative osteoclastic bone resorption with aging. Interactions with other aging physiologic systems, such as muscle, may also confer detrimental effects on the aging skeleton. Conversely, individuals who maintain their BMD experience a lower risk of fractures, disability, and mortality, suggesting that this phenotype may be a marker of successful aging. © 2023 American Physiological Society. Compr Physiol 13:4355-4386, 2023.
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Affiliation(s)
- Robert J Pignolo
- Department of Medicine, Divisions of Geriatric Medicine and Gerontology, Endocrinology, and Hospital Internal Medicine, Mayo Clinic, Rochester, Minnesota, USA.,The Department of Physiology and Biomedical Engineering, and the Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, Minnesota, USA
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Molecular mechanisms of exercise contributing to tissue regeneration. Signal Transduct Target Ther 2022; 7:383. [PMID: 36446784 PMCID: PMC9709153 DOI: 10.1038/s41392-022-01233-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 10/03/2022] [Accepted: 10/17/2022] [Indexed: 12/03/2022] Open
Abstract
Physical activity has been known as an essential element to promote human health for centuries. Thus, exercise intervention is encouraged to battle against sedentary lifestyle. Recent rapid advances in molecular biotechnology have demonstrated that both endurance and resistance exercise training, two traditional types of exercise, trigger a series of physiological responses, unraveling the mechanisms of exercise regulating on the human body. Therefore, exercise has been expected as a candidate approach of alleviating a wide range of diseases, such as metabolic diseases, neurodegenerative disorders, tumors, and cardiovascular diseases. In particular, the capacity of exercise to promote tissue regeneration has attracted the attention of many researchers in recent decades. Since most adult human organs have a weak regenerative capacity, it is currently a key challenge in regenerative medicine to improve the efficiency of tissue regeneration. As research progresses, exercise-induced tissue regeneration seems to provide a novel approach for fighting against injury or senescence, establishing strong theoretical basis for more and more "exercise mimetics." These drugs are acting as the pharmaceutical alternatives of those individuals who cannot experience the benefits of exercise. Here, we comprehensively provide a description of the benefits of exercise on tissue regeneration in diverse organs, mainly focusing on musculoskeletal system, cardiovascular system, and nervous system. We also discuss the underlying molecular mechanisms associated with the regenerative effects of exercise and emerging therapeutic exercise mimetics for regeneration, as well as the associated opportunities and challenges. We aim to describe an integrated perspective on the current advances of distinct physiological mechanisms associated with exercise-induced tissue regeneration on various organs and facilitate the development of drugs that mimics the benefits of exercise.
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Tarantino U, Greggi C, Visconti VV, Cariati I, Bonanni R, Gasperini B, Nardone I, Gasbarra E, Iundusi R. Sarcopenia and bone health: new acquisitions for a firm liaison. Ther Adv Musculoskelet Dis 2022; 14:1759720X221138354. [PMID: 36465879 PMCID: PMC9716454 DOI: 10.1177/1759720x221138354] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/23/2022] [Indexed: 11/15/2023] Open
Abstract
Osteosarcopenia (OS) is a newly defined condition represented by the simultaneous presence of osteopenia/osteoporosis and sarcopenia, the main age-related diseases. The simultaneous coexistence of the two phenotypes derives from the close connection of the main target tissues involved in their pathogenesis: bone and muscle. These two actors constitute the bone-muscle unit, which communicates through a biochemical and mechanical crosstalk which involves multiple factors. Altered pattern of molecular pathways leads to an impairment of both the functionality of the tissue itself and the communication with the complementary tissue, composing the OS pathogenesis. Recent advances in the genetics field have provided the opportunity to delve deeper into the complex biological and molecular mechanisms underlying OS. Unfortunately, there are still many gaps in our understanding of these pathways, but it has proven essential to apply strategies such as exercise and nutritional intervention to counteract OS. New therapeutic strategies that simultaneously target bone and muscle tissue are limited, but recently new targets for the development of dual-action drug therapies have been identified. This narrative review aims to provide an overview of the latest scientific evidence associated with OS, a complex disorder that will pave the way for future research aimed at understanding the bone-muscle-associated pathogenetic mechanisms.
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Affiliation(s)
- Umberto Tarantino
- Department of Clinical Sciences and
Translational Medicine, University of Rome ‘Tor Vergata’, Rome, Italy
- Department of Orthopedics and Traumatology, PTV
Foundation, Rome, Italy
| | - Chiara Greggi
- Department of Clinical Sciences and
Translational Medicine, University of Rome ‘Tor Vergata’, Rome, Italy
| | - Virginia Veronica Visconti
- Department of Clinical Sciences and
Translational Medicine, University of Rome ‘Tor Vergata’, Via Montpellier 1,
00133 Rome, Italy
| | - Ida Cariati
- Department of Biomedicine and Prevention,
University of Rome ‘Tor Vergata’, Rome, Italy
| | - Roberto Bonanni
- Department of Biomedicine and Prevention,
University of Rome ‘Tor Vergata’, Rome, Italy
| | - Beatrice Gasperini
- Department of Biomedicine and Prevention,
University of Rome ‘Tor Vergata’, Rome, Italy
| | - Italo Nardone
- Department of Orthopedics and Traumatology, PTV
Foundation, Rome, Italy
| | - Elena Gasbarra
- Department of Orthopedics and Traumatology, PTV
Foundation, Rome, Italy
| | - Riccardo Iundusi
- Department of Orthopedics and Traumatology,
PTV Foundation, Rome, Italy
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Li G, Zhang L, Lu Z, Yang B, Yang H, Shang P, Jiang JX, Wang D, Xu H. Connexin 43 Channels in Osteocytes Are Necessary for Bone Mass and Skeletal Muscle Function in Aged Male Mice. Int J Mol Sci 2022; 23:13506. [PMID: 36362291 PMCID: PMC9654692 DOI: 10.3390/ijms232113506] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/24/2022] [Accepted: 11/03/2022] [Indexed: 09/26/2023] Open
Abstract
Osteoporosis and sarcopenia (termed "Osteosarcopenia"), the twin-aging diseases, are major contributors to reduced bone mass and muscle weakness in the elderly population. Connexin 43 (Cx43) in osteocytes has been previously reported to play vital roles in bone homeostasis and muscle function in mature mice. The Cx43-formed gap junctions (GJs) and hemichannels (HCs) in osteocytes are important portals for the exchange of small molecules in cell-to-cell and cell-to-extracellular matrix, respectively. However, the roles of Cx43-based GJs and HCs in both bone and muscle aging are still unclear. Here, we used two transgenic mouse models with overexpression of the dominant negative Cx43 mutants primarily in osteocytes driven by the 10-kb Dmp1 promoter, R76W mice (inhibited gap junctions but enhanced hemichannels) and Δ130-136 mice (both gap junction and hemichannels are inhibited), to determine the actions of Cx43-based hemichannels (HCs) and gap junctions (GJs) in the regulation of bone and skeletal muscle from aged mice (18 months) as compared with those from adult mice (10 months). We demonstrated that enhancement of Cx43 HCs reduces bone mass due to increased osteoclast surfaces while the impairment of Cx43 HCs increases osteocyte apoptosis in aged mice caused by reduced PGE2 levels. Furthermore, altered mitochondrial homeostasis with reduced expression of Sirt-1, OPA-1, and Drp-1 resulted in excessive ROS level in muscle soleus (SL) of aged transgenic mice. In vitro, the impairment of Cx43 HCs in osteocytes from aged mice also promoted muscle collagen synthesis through activation of TGFβ/smad2/3 signaling because of reduced PGE2 levels in the PO CM. These findings indicate that the enhancement of Cx43 HCs while GJs are inhibited reduces bone mass, and the impairment of Cx43 HCs inhibits PGE2 level in osteocytes and this reduction promotes muscle collagen synthesis in skeletal muscle through activation of TGFβ/smad2/3 signaling, which together with increased ROS level contributes to reduced muscle force in aged mice.
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Affiliation(s)
- Guobin Li
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
- College of Life Sciences, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Lan Zhang
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
| | - Zhe Lu
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
| | - Baoqiang Yang
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
| | - Hui Yang
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
| | - Peng Shang
- Key Laboratory for Space Bioscience and Biotechnology, Research and Development Institute in Shenzhen, Northwestern Polytechnical University, Shenzhen 518057, China
| | - Jean X. Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Dong’en Wang
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
| | - Huiyun Xu
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China
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Chen J, Shen J, Yang X, Tan H, Yang R, Mo C, Wang Y, Luan X, Huang W, Chen G, Xu X. Exploring the Temporal Correlation of Sarcopenia with Bone Mineral Density and the Effects of Osteoblast-Derived Exosomes on Myoblasts through an Oxidative Stress-Related Gene. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:9774570. [PMID: 36160702 PMCID: PMC9499799 DOI: 10.1155/2022/9774570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/30/2022] [Accepted: 08/05/2022] [Indexed: 11/17/2022]
Abstract
Sarcopenia is an age-related accelerated loss of muscle strength and mass. Bone and muscle are closely related as they are physically adjacent, and bone can influence muscle. However, the temporal association between bone mineral density (BMD) and muscle mass in different regions of the body after adjustment for potential indicators and the mechanisms by which bone influences muscle in sarcopenia remain unclear. Therefore, this study aimed to explore the temporal association between muscle mass and BMD in different regions of the body and mechanisms by which bone regulates muscle in sarcopenia. Here, cross-lagged models were utilized to analyze the temporal association between BMD and muscle mass. We found that low-density lipoprotein (LDL-C) positively predicted appendicular lean mass. Mean whole-body BMD (WBTOT BMD), lumbar spine BMD (LS BMD), and pelvic BMD (PELV BMD) temporally and positively predicted appendicular lean mass, and appendicular lean mass temporally and positively predicted WBTOT BMD, LS BMD, and PELV BMD. Moreover, this study revealed that primary mice femur osteoblasts, but not primary mice skull osteoblasts, induced differentiation of C2C12 myoblasts through exosomes. Furthermore, the level of long noncoding RNA (lncRNA) taurine upregulated 1 (TUG1) was decreased, and the level of lncRNA differentiation antagonizing nonprotein coding RNA (DANCR) was increased in skull osteoblast-derived exosomes, the opposite of femur osteoblast-secreted exosomes. In addition, lncRNA TUG1 enhanced and lncRNA DANCR suppressed the differentiation of myoblasts through regulating the transcription of oxidative stress-related myogenin (Myog) gene by modifying the binding of myogenic factor 5 (Myf5) to the Myog gene promoter via affecting the nuclear translocation of Myf5. The results of the present study may provide novel diagnostic biomarkers and therapeutic targets for sarcopenia.
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Affiliation(s)
- Jingsong Chen
- Department of Endocrinology, The First People's Hospital of Foshan, Foshan, Guangdong 528000, China
| | - Jie Shen
- Department of Endocrinology, Shunde Hospital of Southern Medical University (The First People's Hospital of Shunde), Foshan, Guangdong 528399, China
| | - Xili Yang
- Department of Cardiology, The First People's Hospital of Foshan, Guangdong 528000, China
| | - Huiting Tan
- Department of Endocrinology, The First People's Hospital of Foshan, Foshan, Guangdong 528000, China
| | - Ronghua Yang
- Department of Burn and Plastic Surgery, Guangzhou First People's Hospital, South China University of Technology, Guangzhou, Guangdong, China
| | - Cuiying Mo
- Department of Endocrinology, The First People's Hospital of Foshan, Foshan, Guangdong 528000, China
| | - Ying Wang
- Department of Nuclear Medicine, The First People's Hospital of Foshan, Foshan, Guangdong 528000, China
| | - Xiaojun Luan
- Department of Endocrinology, The First People's Hospital of Foshan, Foshan, Guangdong 528000, China
| | - Wenhua Huang
- Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, Guangdong Provincial Key Laboratory of Medical Biomechanics, National Key Discipline of Human Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong 510515, China
- Guangdong Medical Innovation Platform for Translation of 3D Printing Application, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong 510000, China
| | - Guoqiang Chen
- Department of Rheumatology, The First People's Hospital of Foshan, Foshan, Guangdong 528000, China
| | - Xuejuan Xu
- Department of Endocrinology, The First People's Hospital of Foshan, Foshan, Guangdong 528000, China
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12
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Ko E, Aydin O, Li Z, Gapinske L, Huang KY, Saif T, Bashir R, Kong H. Empowering engineered muscle in biohybrid pump by extending connexin 43 duration with reduced graphene oxides. Biomaterials 2022; 287:121643. [PMID: 35772349 DOI: 10.1016/j.biomaterials.2022.121643] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 06/08/2022] [Accepted: 06/17/2022] [Indexed: 11/20/2022]
Abstract
Engineered skeletal muscle act as therapeutics invaluable to treat injured or diseased muscle and a "living" material essential to assemble biological machinery. For normal development, skeletal myoblasts should express connexin 43, one of the gap junction proteins that promote myoblast fusion and myogenesis, during the early differentiation stage. However, myoblasts cultured in vitro often down-regulate connexin 43 before differentiation, limiting myogenesis and muscle contraction. This study demonstrates that tethering myoblasts with reduced graphene oxide (rGO) slows connexin 43 regression during early differentiation and increases myogenic mRNA synthesis. The whole RNA sequencing also confirms that the rGO on cells increases regulator genes for myogenesis, including troponin, while decreasing negative regulator genes. The resulting myotubes generated a three-fold larger contraction force than the rGO-free myotubes. Accordingly, a valveless biohybrid pump assembled with the rGO-tethered muscle increased the fluid velocity and flow rate considerably. The results of this study would provide an important foundation for developing physiologically relevant muscle and powering up biomachines that will be used for various bioscience studies and unexplored applications.
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Affiliation(s)
- Eunkyung Ko
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Onur Aydin
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Zhengwei Li
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Lauren Gapinske
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Kai-Yu Huang
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Taher Saif
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Rashid Bashir
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
| | - Hyunjoon Kong
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seongbuk-gu, Seoul 02841, South Korea.
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13
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Wei Z, Ge F, Che Y, Wu S, Dong X, Song D. Metabolomics Coupled with Pathway Analysis Provides Insights into Sarco-Osteoporosis Metabolic Alterations and Estrogen Therapeutic Effects in Mice. Biomolecules 2021; 12:41. [PMID: 35053189 PMCID: PMC8773875 DOI: 10.3390/biom12010041] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/13/2021] [Accepted: 12/20/2021] [Indexed: 12/15/2022] Open
Abstract
Postmenopausal osteoporosis (PMOP) and sarcopenia are common diseases that predominantly affect postmenopausal women. In the occurrence and development of these two diseases, they are potentially pathologically connected with each other at various molecular levels. However, the application of metabolomics in sarco-osteoporosis and the metabolic rewiring happening throughout the estrogen loss-replenish process have not been reported. To investigate the metabolic alteration of sarco-osteoporosis and the possible therapeutical effects of estradiol, 24 mice were randomly divided into sham surgery, ovariectomy (OVX), and estradiol-treated groups. Three-dimensional reconstructions and histopathology examination showed significant bone loss after ovariectomy. Estrogen can well protect against OVX-induced bone loss deterioration. UHPLC-Q-TOF/MS was preformed to profile semi- polar metabolites of skeletal muscle samples from all groups. Metabolomics analysis revealed metabolic rewiring occurred in OVX group, most of which can be reversed by estrogen supplementation. In total, 65 differential metabolites were identified, and pathway analysis revealed that sarco-osteoporosis was related to the alterations in purine metabolism, glycerophospholipid metabolism, arginine biosynthesis, tryptophan metabolism, histidine metabolism, oxidative phosphorylation, and thermogenesis, which provided possible explanations for the metabolic mechanism of sarco-osteoporosis. This study indicates that an UHPLC-Q-TOF/MS-based metabolomics approach can elucidate the metabolic reprogramming mechanisms of sarco-osteoporosis and provide biological evidence of the therapeutical effects of estrogen on sarco-osteoporosis.
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Affiliation(s)
- Ziheng Wei
- Department of Orthopedics, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 201620, China;
| | - Fei Ge
- School of Medicine, Shanghai University, Shanghai 200444, China; (F.G.); (Y.C.)
- College of Sciences, Shanghai University, Shanghai 200444, China
| | - Yanting Che
- School of Medicine, Shanghai University, Shanghai 200444, China; (F.G.); (Y.C.)
- College of Sciences, Shanghai University, Shanghai 200444, China
- Institute of Translational Medicine, Shanghai University, Shanghai 200444, China
| | - Si Wu
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Xin Dong
- School of Medicine, Shanghai University, Shanghai 200444, China; (F.G.); (Y.C.)
- Institute of Translational Medicine, Shanghai University, Shanghai 200444, China
| | - Dianwen Song
- Department of Orthopedics, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 201620, China;
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14
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Berger JM, Karsenty G. Osteocalcin and the Physiology of Danger. FEBS Lett 2021; 596:665-680. [PMID: 34913486 PMCID: PMC9020278 DOI: 10.1002/1873-3468.14259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 11/29/2021] [Accepted: 12/07/2021] [Indexed: 12/02/2022]
Abstract
Bone biology has long been driven by the question as to what molecules affect cell differentiation or the functions of bone. Exploring this issue has been an extraordinarily powerful way to improve our knowledge of bone development and physiology. More recently, a second question has emerged: does bone have other functions besides making bone? Addressing this conundrum revealed that the bone-derived hormone osteocalcin affects a surprisingly large number of organs and physiological processes, including acute stress response. This review will focus on this emerging aspect of bone biology taking osteocalcin as a case study and will show how classical and endocrine functions of bone help to define a new functional identity for this tissue.
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Affiliation(s)
- Julian Meyer Berger
- Department of Genetics and Development, Vagelos College of Physicians and Surgeons, Columbia University, NY, 10032, USA
| | - Gerard Karsenty
- Department of Genetics and Development, Vagelos College of Physicians and Surgeons, Columbia University, NY, 10032, USA
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15
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Lu W, Xiao W, Xie W, Fu X, Pan L, Jin H, Yu Y, Zhang Y, Li Y. The Role of Osteokines in Sarcopenia: Therapeutic Directions and Application Prospects. Front Cell Dev Biol 2021; 9:735374. [PMID: 34650980 PMCID: PMC8505767 DOI: 10.3389/fcell.2021.735374] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/07/2021] [Indexed: 12/14/2022] Open
Abstract
Sarcopenia is an age-related disease in which muscle mass, strength and function may decline with age or can be secondary to cachexia or malnutrition and can lead to weakness, falls and even death. With the increase in life expectancy, sarcopenia has become a major threat to the health of the elderly. Currently, our understanding of bone-muscle interactions is not limited to their mechanical coupling. Bone and muscle have been identified as secretory endocrine organs, and their interaction may affect the function of each. Both muscle-derived factors and osteokines can play a role in regulating muscle and bone metabolism via autocrine, paracrine and endocrine mechanisms. Herein, we comprehensively summarize the latest research progress on the effects of the osteokines FGF-23, IGF-1, RANKL and osteocalcin on muscle to explore whether these cytokines can be utilized to treat and prevent sarcopenia.
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Affiliation(s)
- Wenhao Lu
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Wenfeng Xiao
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Wenqing Xie
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Xin Fu
- Xiangya School of Medicine, Central South University, Changsha, China
| | - Linyuan Pan
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Hongfu Jin
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Yongle Yu
- Xiangya School of Medicine, Central South University, Changsha, China
| | - Yi Zhang
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Yusheng Li
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
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16
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Youlten SE, Kemp JP, Logan JG, Ghirardello EJ, Sergio CM, Dack MRG, Guilfoyle SE, Leitch VD, Butterfield NC, Komla-Ebri D, Chai RC, Corr AP, Smith JT, Mohanty ST, Morris JA, McDonald MM, Quinn JMW, McGlade AR, Bartonicek N, Jansson M, Hatzikotoulas K, Irving MD, Beleza-Meireles A, Rivadeneira F, Duncan E, Richards JB, Adams DJ, Lelliott CJ, Brink R, Phan TG, Eisman JA, Evans DM, Zeggini E, Baldock PA, Bassett JHD, Williams GR, Croucher PI. Osteocyte transcriptome mapping identifies a molecular landscape controlling skeletal homeostasis and susceptibility to skeletal disease. Nat Commun 2021; 12:2444. [PMID: 33953184 PMCID: PMC8100170 DOI: 10.1038/s41467-021-22517-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 03/11/2021] [Indexed: 12/17/2022] Open
Abstract
Osteocytes are master regulators of the skeleton. We mapped the transcriptome of osteocytes from different skeletal sites, across age and sexes in mice to reveal genes and molecular programs that control this complex cellular-network. We define an osteocyte transcriptome signature of 1239 genes that distinguishes osteocytes from other cells. 77% have no previously known role in the skeleton and are enriched for genes regulating neuronal network formation, suggesting this programme is important in osteocyte communication. We evaluated 19 skeletal parameters in 733 knockout mouse lines and reveal 26 osteocyte transcriptome signature genes that control bone structure and function. We showed osteocyte transcriptome signature genes are enriched for human orthologs that cause monogenic skeletal disorders (P = 2.4 × 10-22) and are associated with the polygenic diseases osteoporosis (P = 1.8 × 10-13) and osteoarthritis (P = 1.6 × 10-7). Thus, we reveal the molecular landscape that regulates osteocyte network formation and function and establish the importance of osteocytes in human skeletal disease.
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Affiliation(s)
- Scott E Youlten
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
| | - John P Kemp
- University of Queensland Diamantina Institute, UQ, Brisbane, QLD, Australia
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
| | - John G Logan
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Elena J Ghirardello
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Claudio M Sergio
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Michael R G Dack
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Siobhan E Guilfoyle
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Victoria D Leitch
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
- RMIT Centre for Additive Manufacturing, School of Engineering, RMIT University, Melbourne, VIC, UK
| | - Natalie C Butterfield
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Davide Komla-Ebri
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Ryan C Chai
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Alexander P Corr
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
- Faculty of Science, University of Bath, Bath, UK
| | - James T Smith
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
- Faculty of Science, University of Bath, Bath, UK
| | - Sindhu T Mohanty
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - John A Morris
- New York Genome Center, New York, NY, USA
- Faculty of Arts and Science, Department of Biology, New York University, New York, NY, USA
| | - Michelle M McDonald
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
| | - Julian M W Quinn
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Amelia R McGlade
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Nenad Bartonicek
- Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Darlinghurst, Sydney, NSW, Australia
| | - Matt Jansson
- Viapath Genetics Laboratory, Viapath Analytics LLP, Guy's Hospital, London, UK
- Department of Clinical Genetics, Guy's Hospital, London, UK
| | - Konstantinos Hatzikotoulas
- Institute of Translational Genomics, Helmholtz Zentrum München - German Research Center for Environmental Health, Phoenix, AZ, USA
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Melita D Irving
- Department of Clinical Genetics, Guy's and St Thomas' NHS Trust, London, UK
| | | | | | - Emma Duncan
- Faculty of Life Sciences and Medicine, Department of Twin Research & Genetic Epidemiology, School of Life Course Sciences, King's College London, London, UK
- Australian Translational Genomics Centre, Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology, Brisbane, QLD, Australia
- Faculty of Medicine, University of Queensland, St Lucia, QLD, Australia
| | - J Brent Richards
- Faculty of Life Sciences and Medicine, Department of Twin Research & Genetic Epidemiology, School of Life Course Sciences, King's College London, London, UK
- Faculty of Medicine, McGill University, Quebec, Canada
| | | | | | - Robert Brink
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
- Division of Immunology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Tri Giang Phan
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
- Division of Immunology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - John A Eisman
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia
- School of Medicine Sydney, University of Notre Dame Australia, Fremantle, Australia
| | - David M Evans
- University of Queensland Diamantina Institute, UQ, Brisbane, QLD, Australia
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
| | - Eleftheria Zeggini
- Institute of Translational Genomics, Helmholtz Zentrum München - German Research Center for Environmental Health, Phoenix, AZ, USA
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Paul A Baldock
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - J H Duncan Bassett
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.
| | - Graham R Williams
- Molecular Endocrinology Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.
| | - Peter I Croucher
- Bone Biology, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia.
- St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, NSW, Australia.
- School of Biotechnology and Biomolecular Sciences, UNSW Australia, Sydney, Australia.
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17
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Smith C, Lin X, Scott D, Brennan-Speranza TC, Al Saedi A, Moreno-Asso A, Woessner M, Bani Hassan E, Eynon N, Duque G, Levinger I. Uncovering the Bone-Muscle Interaction and Its Implications for the Health and Function of Older Adults (the Wellderly Project): Protocol for a Randomized Controlled Crossover Trial. JMIR Res Protoc 2021; 10:e18777. [PMID: 33835038 PMCID: PMC8065561 DOI: 10.2196/18777] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 11/29/2020] [Accepted: 12/01/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Bone and muscle are closely linked anatomically, biochemically, and metabolically. Acute exercise affects both bone and muscle, implying a crosstalk between the two systems. However, how these two systems communicate is still largely unknown. We will explore the role of undercarboxylated osteocalcin (ucOC) in this crosstalk. ucOC is involved in glucose metabolism and has a potential role in muscle maintenance and metabolism. OBJECTIVE The proposed trial will determine if circulating ucOC levels in older adults at baseline and following acute exercise are associated with parameters of muscle function and if the ucOC response to exercise varies between older adults with low muscle quality and those with normal or high muscle quality. METHODS A total of 54 men and women aged 60 years or older with no history of diabetes and warfarin and vitamin K use will be recruited. Screening tests will be performed, including those for functional, anthropometric, and clinical presentation. On the basis of muscle quality, a combined equation of lean mass (leg appendicular skeletal muscle mass in kg) and strength (leg press; one-repetition maximum), participants will be stratified into a high or low muscle function group and randomized into the controlled crossover acute intervention. Three visits will be performed approximately 7 days apart, and acute aerobic exercise, acute resistance exercise, and a control session (rest) will be completed in any order. Our primary outcome for this study is the effect of acute exercise on ucOC in older adults with low muscle function and those with high muscle function. RESULTS The trial is active and ongoing. Recruitment began in February 2018, and 38 participants have completed the study as of May 26, 2019. CONCLUSIONS This study will provide novel insights into bone and muscle crosstalk in older adults, potentially identifying new clinical biomarkers and mechanistic targets for drug treatments for sarcopenia and other related musculoskeletal conditions. TRIAL REGISTRATION Australia New Zealand Clinical Trials Registry ACTRN12618001756213; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375925. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID) DERR1-10.2196/18777.
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Affiliation(s)
- Cassandra Smith
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia.,Australian Institute for Musculoskeletal Science, University of Melbourne and Western Health, Melbourne, VIC, Australia
| | - Xuzhu Lin
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia
| | - David Scott
- Australian Institute for Musculoskeletal Science, University of Melbourne and Western Health, Melbourne, VIC, Australia.,Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia.,Department of Medicine, School of Clinical Sciences at Monash Health, Monash University, Clayton, VIC, Australia
| | - Tara C Brennan-Speranza
- School of Medical Sciences and School of Public Health, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia
| | - Ahmed Al Saedi
- Australian Institute for Musculoskeletal Science, University of Melbourne and Western Health, Melbourne, VIC, Australia.,Department of Medicine-Western Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Alba Moreno-Asso
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia.,Australian Institute for Musculoskeletal Science, University of Melbourne and Western Health, Melbourne, VIC, Australia
| | - Mary Woessner
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia
| | - Ebrahim Bani Hassan
- Australian Institute for Musculoskeletal Science, University of Melbourne and Western Health, Melbourne, VIC, Australia.,Department of Medicine-Western Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Nir Eynon
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia
| | - Gustavo Duque
- Australian Institute for Musculoskeletal Science, University of Melbourne and Western Health, Melbourne, VIC, Australia.,Department of Medicine-Western Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Itamar Levinger
- Australian Institute for Musculoskeletal Science, University of Melbourne and Western Health, Melbourne, VIC, Australia.,Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia
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18
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Smith C, Lewis JR, Sim M, Lim WH, Lim EM, Blekkenhorst LC, Brennan-Speranza TC, Adams L, Byrnes E, Duque G, Levinger I, Prince RL. Higher Undercarboxylated to Total Osteocalcin Ratio Is Associated With Reduced Physical Function and Increased 15-Year Falls-Related Hospitalizations: The Perth Longitudinal Study of Aging Women. J Bone Miner Res 2021; 36:523-530. [PMID: 33615560 DOI: 10.1002/jbmr.4208] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 10/20/2020] [Accepted: 11/02/2020] [Indexed: 11/07/2022]
Abstract
Evidence from animal models suggests that undercarboxylated osteocalcin (ucOC) is involved in muscle mass maintenance and strength. In humans, the ucOC to total (t)OC ratio may be related to muscle strength and perhaps physical function and falls risk, but data are limited. We tested the hypothesis that ucOC and ucOC/tOC ratio are associated with muscle function (muscle strength and physical function) in older women and 15-year falls-related hospitalizations. Serum tOC and ucOC were assessed in 1261 older women (mean age 75.2 ± 2.7 years) forming the Perth Longitudinal Study of Aging Women (1998 to 2013). Timed-up-and-go (TUG) and grip strength were assessed at baseline and at 5 years. Falls-related hospitalizations (14.5-year follow-up) were captured by the Hospital Morbidity Data Collection, via the Western Australian Data Linkage System. At baseline, women with higher ucOC/tOC ratio (quartile 4) had slower TUG performance compared with quartile 1 (~0.68 seconds, p < .01). Grip strength and 5-year change of TUG and grip were not different (p > .05) between quartiles. Fear of falling limiting house, outdoor, and combined activities was significantly different across quartiles (p < .05). Higher ucOC/tOC was significantly associated with poorer TUG performance at baseline and 5-year change in performance, increased walking aid use, and fear of falling (all p < .05). Higher ucOC was related to lower grip strength at baseline (p < .05) but not 5-year change in strength. Those with the highest ucOC/tOC had greater falls-related hospitalizations (unadjusted log rank, p = .004) remaining significant after adjusting for key variables (hazard ratio [HR] = 1.31, 95% confidence interval [CI] 1.09-1.57, p = .004). We identified a large proportion of older women with high ucOC/tOC ratio who had reduced physical function, including its long-term decline and increased risk of falls-related hospitalizations. Early identification of women at higher risk can enable prevention and intervention strategies to occur, reducing risk for injurious falls. © 2020 American Society for Bone and Mineral Research (ASBMR)..
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Affiliation(s)
- Cassandra Smith
- Institute for Health and Sport (IHES), Victoria University, Melbourne, Australia.,Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St. Albans, Australia
| | - Joshua R Lewis
- School of Medical and Health Sciences, Edith Cowan University, Perth, Australia.,Centre for Kidney Research, Children's Hospital at Westmead, School of Public Health, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia.,Medical School, University Western Australia, Perth, Australia
| | - Marc Sim
- School of Medical and Health Sciences, Edith Cowan University, Perth, Australia.,Medical School, University Western Australia, Perth, Australia
| | - Wai H Lim
- Medical School, University Western Australia, Perth, Australia.,Department of Renal Medicine, Sir Charles Gairdner Hospital, Perth, Australia
| | - Ee Mun Lim
- Department of Clinical Biochemistry, PathWest Laboratory Medicine, Queen Elizabeth II Medical Centre, Perth, Australia.,Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Australia
| | - Lauren C Blekkenhorst
- School of Medical and Health Sciences, Edith Cowan University, Perth, Australia.,Medical School, University Western Australia, Perth, Australia
| | - Tara C Brennan-Speranza
- Department of Physiology, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, Australia.,School of Public Health, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
| | - Leon Adams
- Medical School, University Western Australia, Perth, Australia.,Department of Hepatology, Sir Charles Gairdner Hospital, Nedlands, Australia
| | - Elizabeth Byrnes
- Department of Clinical Biochemistry, PathWest Laboratory Medicine, Queen Elizabeth II Medical Centre, Perth, Australia
| | - Gustavo Duque
- Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St. Albans, Australia.,Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, Australia
| | - Itamar Levinger
- Institute for Health and Sport (IHES), Victoria University, Melbourne, Australia.,Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St. Albans, Australia
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19
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Smith C, Tacey A, Mesinovic J, Scott D, Lin X, Brennan-Speranza TC, Lewis JR, Duque G, Levinger I. The effects of acute exercise on bone turnover markers in middle-aged and older adults: A systematic review. Bone 2021; 143:115766. [PMID: 33227507 DOI: 10.1016/j.bone.2020.115766] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 11/08/2020] [Accepted: 11/18/2020] [Indexed: 11/25/2022]
Abstract
BACKGROUND Bone turnover is the cellular machinery responsible for bone integrity and strength and, in the clinical setting, it is assessed using bone turnover markers (BTMs). Acute exercise can induce mechanical stress on bone which is needed for bone remodelling, but to date, there are conflicting results in regards to the effects of varying mechanical stimuli on BTMs. OBJECTIVES This systematic review examines the effects of acute aerobic, resistance and impact exercises on BTMs in middle and older-aged adults and examines whether the responses are determined by the exercise mode, intensity, age and sex. METHODS We searched PubMed, SCOPUS, Web of Science and EMBASE up to 22nd April 2020. Eligibility criteria included randomised controlled trials (RCTs) and single-arm studies that included middle-aged (50 to 65 years) and older adults (>65 years) and, a single-bout, acute-exercise (aerobic, resistance, impact) intervention with measurement of BTMs. PROSPERO registration number CRD42020145359. RESULTS Thirteen studies were included; 8 in middle-aged (n = 275, 212 women/63 men, mean age = 57.9 ± 1.5 years) and 5 in older adults (n = 93, 50 women/43 men, mean age = 68.2 ± 2.2 years). Eleven studies included aerobic exercise (AE, 7 middle-aged/4 older adults), and two included resistance exercise (RE, both middle-aged). AE significantly increased C-terminal telopeptide (CTX), alkaline phosphatase (ALP) and bone-ALP in middle-aged and older adults. AE also significantly increased total osteocalcin (tOC) in middle-aged men and Procollagen I Carboxyterminal Propeptide and Cross-Linked Carboxyterminal Telopeptide of Type I Collagen in older women. RE alone decreased ALP in older adults. In middle-aged adults, RE with impact had no effect on tOC or BALP, but significantly decreased CTX. Impact (jumping) exercise alone increased Procollagen Type 1 N Propeptide and tOC in middle-aged women. CONCLUSION Acute exercise is an effective tool to modify BTMs, however, the response appears to be exercise modality-, intensity-, age- and sex-specific. There is further need for higher quality and larger RCTs in this area.
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Affiliation(s)
- Cassandra Smith
- Institute for Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia; Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia
| | - Alexander Tacey
- Institute for Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia; Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia
| | - Jakub Mesinovic
- School of Clinical Sciences at Monash Health, Monash University, Melbourne, VIC, Australia
| | - David Scott
- Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia; School of Clinical Sciences at Monash Health, Monash University, Melbourne, VIC, Australia; Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria, Australia
| | - Xuzhu Lin
- Diabetes & Metabolic Disease Laboratory, St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia
| | - Tara C Brennan-Speranza
- Department of Physiology, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, Australia; School of Public Health, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Joshua R Lewis
- School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia; Centre for Kidney Research, Children's Hospital at Westmead, School of Public Health, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia; Medical School, University Western Australia, Perth, WA, Australia
| | - Gustavo Duque
- Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia; Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia
| | - Itamar Levinger
- Institute for Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia; Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia.
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20
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Osteocytic Connexin43 Channels Regulate Bone-Muscle Crosstalk. Cells 2021; 10:cells10020237. [PMID: 33530465 PMCID: PMC7911162 DOI: 10.3390/cells10020237] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 02/01/2023] Open
Abstract
Bone–muscle crosstalk plays an important role in skeletal biomechanical function, the progression of numerous pathological conditions, and the modulation of local and distant cellular environments. Previous work has revealed that the deletion of connexin (Cx) 43 in osteoblasts, and consequently, osteocytes, indirectly compromises skeletal muscle formation and function. However, the respective roles of Cx43-formed gap junction channels (GJs) and hemichannels (HCs) in the bone–muscle crosstalk are poorly understood. To this end, we used two Cx43 osteocyte-specific transgenic mouse models expressing dominant negative mutants, Δ130–136 (GJs and HCs functions are inhibited), and R76W (only GJs function is blocked), to determine the effect of these two types of Cx43 channels on neighboring skeletal muscle. Blockage of osteocyte Cx43 GJs and HCs in Δ130–136 mice decreased fast-twitch muscle mass with reduced muscle protein synthesis and increased muscle protein degradation. Both R76W and Δ130–136 mice exhibited decreased muscle contractile force accompanied by a fast-to-slow fiber transition in typically fast-twitch muscles. In vitro results further showed that myotube formation of C2C12 myoblasts was inhibited after treatment with the primary osteocyte conditioned media (PO CM) from R76W and Δ130–136 mice. Additionally, prostaglandin E2 (PGE2) level was significantly reduced in both the circulation and PO CM of the transgenic mice. Interestingly, the injection of PGE2 to the transgenic mice rescued fast-twitch muscle mass and function; however, this had little effect on protein synthesis and degradation. These findings indicate a channel-specific response: inhibition of osteocytic Cx43 HCs decreases fast-twitch skeletal muscle mass alongside reduced protein synthesis and increased protein degradation. In contrast, blockage of Cx43 GJs results in decreased fast-twitch skeletal muscle contractile force and myogenesis, with PGE2 partially accounting for the measured differences.
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21
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Moore AC, Wu J, Jewlal E, Barr K, Laird DW, Willmore KE. Effects of Reduced Connexin43 Function on Mandibular Morphology and Osteogenesis in Mutant Mouse Models of Oculodentodigital Dysplasia. Calcif Tissue Int 2020; 107:611-624. [PMID: 32902679 DOI: 10.1007/s00223-020-00753-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 08/29/2020] [Indexed: 10/23/2022]
Abstract
Mutations in the gene encoding the gap-junctional protein connexin43 (Cx43) are the cause of the human disease oculodentodigital dysplasia (ODDD). The mandible is often affected in this disease, with clinical reports describing both mandibular overgrowth and conversely, retrognathia. These seemingly opposing observations underscore our relative lack of understanding of how ODDD affects mandibular morphology. Using two mutant mouse models that mimic the ODDD phenotype (I130T/+ and G60S/+), we sought to uncover how altered Cx43 function may affect mandibular development. Specifically, mandibles of newborn mice were imaged using micro-CT, to enable statistical comparisons of shape. Tissue-level comparisons of key regions of the mandible were conducted using histomorphology, and we quantified the mRNA expression of several cartilage and bone cell differentiation markers. Both G60S/+ and I130T/+ mutant mice had altered mandibular morphology compared to their wildtype counterparts, and the morphological effects were similarly localized for both mutants. Specifically, the biggest phenotypic differences in mutant mice were focused in regions exposed to mechanical forces, such as alveolar bone, muscular attachment sites, and articular surfaces. Histological analyses revealed differences in ossification of the intramembranous bone of the mandibles of both mutant mice compared to their wildtype littermates. However, chondrocyte organization within the secondary cartilages of the mandible was unaffected in the mutant mice. Overall, our results suggest that the morphological differences seen in G60S/+ and I130T/+ mouse mandibles are due to delayed ossification and suggest that mechanical forces may exacerbate the effects of ODDD on the skeleton.
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Affiliation(s)
- Alyssa C Moore
- Department of Anatomy & Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
| | - Jessica Wu
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
| | - Elizabeth Jewlal
- Department of Anatomy & Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
| | - Kevin Barr
- Department of Anatomy & Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
| | - Dale W Laird
- Department of Anatomy & Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
| | - Katherine E Willmore
- Department of Anatomy & Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada.
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22
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Shen H, Schwartz AG, Civitelli R, Thomopoulos S. Connexin 43 Is Necessary for Murine Tendon Enthesis Formation and Response to Loading. J Bone Miner Res 2020; 35:1494-1503. [PMID: 32227614 PMCID: PMC7725385 DOI: 10.1002/jbmr.4018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 03/08/2020] [Accepted: 03/21/2020] [Indexed: 12/28/2022]
Abstract
The enthesis is a mineralized fibrocartilage transition that attaches tendon to bone and is vital for musculoskeletal function. Despite recent studies demonstrating the necessity of muscle loading for enthesis formation, the mechanisms that regulate enthesis formation and mechanoresponsiveness remain unclear. Therefore, the current study investigated the role of the gap junction protein connexin 43 in these processes by deleting Gja1 (the Cx43 gene) in the tendon and enthesis. Compared with their wild-type (WT) counterparts, mice lacking Cx43 showed disrupted entheseal cell alignment, reduced mineralized fibrocartilage, and impaired biomechanical properties of the supraspinatus tendon entheses during postnatal development. Cx43-deficient mice also exhibited reduced ability to complete a treadmill running protocol but no apparent deficits in daily activity, metabolic indexes, shoulder muscle size, grip strength, and major trabecular bone properties of the adjacent humeral head. To examine enthesis mechanoresponsiveness, young adult mice were subjected to modest treadmill exercise. Gja1 deficiency in the tendon and enthesis reduced entheseal anabolic responses to treadmill exercise: WT mice had increased expression of Sox9, Ihh, and Gli1 and increased Brdu incorporation, whereas Cx43-deficient mice showed no changes or decreased levels with exercise. Collectively, the results demonstrated an essential role for Cx43 in postnatal tendon enthesis formation, function, and response to loading; results further provided evidence implicating a link between Cx43 function and the hedgehog signaling pathway. © 2020 American Society for Bone and Mineral Research.
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Affiliation(s)
- Hua Shen
- Department of Orthopaedic Surgery, Washington University, St. Louis, MO, USA
| | - Andrea G Schwartz
- Department of Orthopaedic Surgery, Washington University, St. Louis, MO, USA
| | - Roberto Civitelli
- Department of Internal Medicine, Division of Bone and Mineral Disease, Washington University, St. Louis, MO, USA
| | - Stavros Thomopoulos
- Department of Orthopedic Surgery, Columbia University, New York, NY, USA.,Department of Biomedical Engineering, Columbia University, New York, NY, USA
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23
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Herrmann M, Engelke K, Ebert R, Müller-Deubert S, Rudert M, Ziouti F, Jundt F, Felsenberg D, Jakob F. Interactions between Muscle and Bone-Where Physics Meets Biology. Biomolecules 2020; 10:biom10030432. [PMID: 32164381 PMCID: PMC7175139 DOI: 10.3390/biom10030432] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/27/2020] [Accepted: 03/05/2020] [Indexed: 02/06/2023] Open
Abstract
Muscle and bone interact via physical forces and secreted osteokines and myokines. Physical forces are generated through gravity, locomotion, exercise, and external devices. Cells sense mechanical strain via adhesion molecules and translate it into biochemical responses, modulating the basic mechanisms of cellular biology such as lineage commitment, tissue formation, and maturation. This may result in the initiation of bone formation, muscle hypertrophy, and the enhanced production of extracellular matrix constituents, adhesion molecules, and cytoskeletal elements. Bone and muscle mass, resistance to strain, and the stiffness of matrix, cells, and tissues are enhanced, influencing fracture resistance and muscle power. This propagates a dynamic and continuous reciprocity of physicochemical interaction. Secreted growth and differentiation factors are important effectors of mutual interaction. The acute effects of exercise induce the secretion of exosomes with cargo molecules that are capable of mediating the endocrine effects between muscle, bone, and the organism. Long-term changes induce adaptations of the respective tissue secretome that maintain adequate homeostatic conditions. Lessons from unloading, microgravity, and disuse teach us that gratuitous tissue is removed or reorganized while immobility and inflammation trigger muscle and bone marrow fatty infiltration and propagate degenerative diseases such as sarcopenia and osteoporosis. Ongoing research will certainly find new therapeutic targets for prevention and treatment.
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Affiliation(s)
- Marietta Herrmann
- Orthopedic Department, Bernhard-Heine-Center for Locomotion Research, IZKF Research Group Tissue regeneration in musculoskeletal diseases, University Hospital Würzburg, University of Wuerzburg, 97070 Würzburg, Germany;
| | - Klaus Engelke
- Department of Medicine 3, FAU University Erlangen-Nürnberg and Universitätsklinikum Erlangen, 91054 Erlangen, Germany;
| | - Regina Ebert
- Orthopedic Department, Bernhard-Heine-Center for Locomotion Research, University of Würzburg, IGZ, 97076 Würzburg, Germany; (R.E.)
| | - Sigrid Müller-Deubert
- Orthopedic Department, Bernhard-Heine-Center for Locomotion Research, University of Würzburg, IGZ, 97076 Würzburg, Germany; (R.E.)
| | - Maximilian Rudert
- Orthopedic Department, Bernhard-Heine-Center for Locomotion Research, University of Würzburg, 97074 Würzburg, Germany;
| | - Fani Ziouti
- Department of Internal Medicine II, University Hospital Würzburg, 97080 Würzburg, Germany; (F.Z.); (F.J.)
| | - Franziska Jundt
- Department of Internal Medicine II, University Hospital Würzburg, 97080 Würzburg, Germany; (F.Z.); (F.J.)
| | - Dieter Felsenberg
- Privatpraxis für Muskel- und Knochenkrankheiten, 12163 Berlin Germany;
| | - Franz Jakob
- Orthopedic Department, Bernhard-Heine-Center for Locomotion Research, University of Würzburg, IGZ, 97076 Würzburg, Germany; (R.E.)
- Orthopedic Department, Bernhard-Heine-Center for Locomotion Research, University of Würzburg, 97074 Würzburg, Germany;
- Correspondence:
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24
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Active acetylcholine receptors prevent the atrophy of skeletal muscles and favor reinnervation. Nat Commun 2020; 11:1073. [PMID: 32103010 PMCID: PMC7044284 DOI: 10.1038/s41467-019-14063-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 12/10/2019] [Indexed: 12/17/2022] Open
Abstract
Denervation of skeletal muscles induces severe muscle atrophy, which is preceded by cellular alterations such as increased plasma membrane permeability, reduced resting membrane potential and accelerated protein catabolism. The factors that induce these changes remain unknown. Conversely, functional recovery following denervation depends on successful reinnervation. Here, we show that activation of nicotinic acetylcholine receptors (nAChRs) by quantal release of acetylcholine (ACh) from motoneurons is sufficient to prevent changes induced by denervation. Using in vitro assays, ACh and non-hydrolysable ACh analogs repressed the expression of connexin43 and connexin45 hemichannels, which promote muscle atrophy. In co-culture studies, connexin43/45 hemichannel knockout or knockdown increased innervation of muscle fibers by dorsal root ganglion neurons. Our results show that ACh released by motoneurons exerts a hitherto unknown function independent of myofiber contraction. nAChRs and connexin hemichannels are potential molecular targets for therapeutic intervention in a variety of pathological conditions with reduced synaptic neuromuscular transmission. Denervation of muscle fibres induces muscle atrophy, via mechanisms that remain unclear. Here, the authors show that binding of acetylcoline to its receptor at the neuromuscular junction represses the expression of connexins 43 and 45, which promote atrophy, and is sufficient to prevent denervation-induced loss of myofibre mass.
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25
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Wang T, Yu X, He C. Pro-inflammatory Cytokines: Cellular and Molecular Drug Targets for Glucocorticoid-induced-osteoporosis via Osteocyte. Curr Drug Targets 2020; 20:1-15. [PMID: 29618305 DOI: 10.2174/1389450119666180405094046] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/11/2018] [Accepted: 03/21/2018] [Indexed: 02/08/2023]
Abstract
Glucocorticoids are widely used to treat varieties of allergic and autoimmune diseases, however, long-term application results in glucocorticoid-induced osteoporosis (GIOP). Inflammatory cytokines: tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) play important regulatory roles in bone metabolism, but their roles in GIOP remain largely unknown. Osteocytes can modulate the formation and function of both osteoblasts and osteoclasts, directly via gap junctions, or indirectly by transferring molecule signaling. Apoptotic osteocytes release RANKL, HMGB1 and pro-inflammatory cytokines to stimulate osteoclastogenesis. Moreover, osteocytes can secrete FGF23 to regulate bone metabolism. Exposure to high levels of GCs can drive osteocyte apoptosis and influence gap junctions, leading to bone loss. GCs treatment is regarded to produce more FGF23 to inhibit bone mineralization. GCs also disrupt the vascular to decrease osteocyte feasibility and mineral appositional rate, resulting in a decline in bone strength. Apoptotic bodies from osteocytes induced by GCs treatment can enhance production of TNF-α and IL-6. On the other hand, TNF-α and IL-6 show synergistic effects by altering osteocytes signaling towards osteoclasts and osteoblasts. In addition, TNF-α can induce osteocyte apoptosis and attribute to a worsened bone quality in GCs. IL-6 and osteocytes may interact with each other. Therefore, we hypothesize that GCs regulate osteocyteogenesis through TNF-α and IL-6, which are highly expressed around osteocyte undergoing apoptosis. In the present review, we summarized the roles of osteocytes in regulating osteoblasts and osteoclasts. Furthermore, the mechanism of GCs altered relationship between osteocytes and osteoblasts/osteoclasts. In addition, we discussed the roles of TNF-α and IL-6 in GIOP by modulating osteocytes. Lastly, we discussed the possibility of using pro-inflammatory signaling pathway as therapeutic targets to develop drugs for GIOP.
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Affiliation(s)
- Tiantian Wang
- Department of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.,Key Laboratory of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.,Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Key Laboratory of Biotherapy/Collaborative Innovation Center of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, China
| | - Xijie Yu
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Key Laboratory of Biotherapy/Collaborative Innovation Center of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, China
| | - Chengqi He
- Department of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.,Key Laboratory of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
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26
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Kobayashi F, Uehara O, Ito C, Furusawa M, Abiko Y, Muramatsu T. DNA methylation of GJA1, BMP2 and BMP4 in a human cementoblast cell line induced by lipopolysaccharide. Int Endod J 2020; 53:804-811. [PMID: 32011747 DOI: 10.1111/iej.13275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 01/30/2020] [Accepted: 01/30/2020] [Indexed: 11/26/2022]
Abstract
AIM To examine DNA methylation of GJA1, BMP2 and BMP4 in human cementoblasts (HCEM) induced by lipopolysaccharide (LPS). METHODOLOGY HCEM were cultured in osteoinduction medium. After 24 h, Escherichia coli LPS (1 μg/mL) was added to the medium, which was changed every 2-3 days. Untreated samples were used as controls. Messenger RNA was extracted after 4 weeks, and quantitative real-time polymerase chain reaction (qRT-PCR) for GJA1, BMP2, BMP4 and DNMT1 was performed. Genomic DNA was extracted after 4 weeks, and quantitative methylation-specific polymerase chain reaction was carried out for GJA1, BMP2 and BMP4. To detect mineralization, alizarin red and alkaline phosphatase staining were performed. The cells were also treated with the DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine (5Aza) and examined. The significance of differences amongst groups was assessed using a two-way analysis of variance (ANOVA) followed by Bonferroni's multiple comparison test with P < 0.05 being significant. RESULTS Decreased expression of mRNA was seen in GJA1, BMP2 and BMP4 after 4 weeks (P < 0.05). DNA hypermethylation was detected in GJA1, BMP2 and BMP4 (P < 0.05). Alizarin red staining and alkaline phosphatase staining revealed decreased mineralization levels in HCEM stimulated with LPS. 5Aza abolished the effects of DNA methylation in HCEM stimulated with LPS. CONCLUSIONS These results suggest that long-term LPS stimulation induces DNA methylation of GJA1, BMP2 and BMP4 in HCEM.
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Affiliation(s)
- F Kobayashi
- Department of Endodontics, Tokyo Dental College, Tokyo, Japan
| | - O Uehara
- Division of Disease Control and Molecular Epidemiology, Department of Oral Growth and Development, Health Sciences University of Hokkaido, Tobetsu, Japan
| | - C Ito
- Oral Health Science Center, Tokyo Dental College, Tokyo, Japan
| | - M Furusawa
- Department of Endodontics, Tokyo Dental College, Tokyo, Japan
| | - Y Abiko
- Division of Oral Medicine and Pathology, Department of Human Biology and Pathophysiology, School of Dentistry, Health Sciences University of Hokkaido, Tobetsu, Japan
| | - T Muramatsu
- Department of Operative Dentistry, Cariology and Pulp Biology, Tokyo Dental College, Tokyo, Japan
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27
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Smith C, Voisin S, Al Saedi A, Phu S, Brennan-Speranza T, Parker L, Eynon N, Hiam D, Yan X, Scott D, Blekkenhorst LC, Lewis JR, Seeman E, Byrnes E, Flicker L, Duque G, Yeap BB, Levinger I. Osteocalcin and its forms across the lifespan in adult men. Bone 2020; 130:115085. [PMID: 31622778 DOI: 10.1016/j.bone.2019.115085] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 02/02/2023]
Abstract
PURPOSE Osteocalcin (OC), an osteoblast-specific secreted protein expressed by mature osteoblasts, is used in clinical practice and in research as a marker of bone turnover. The carboxylated (cOC) and undercarboxylated (ucOC) forms may have a different biological function but age-specific reference ranges for these components are not established. Given the different physiological roles, development of reference ranges may help to identify people at risk for bone disease. METHODS Blood was collected in the morning after an overnight fast from 236 adult men (18 to 92 years old) free of diabetes, antiresorptive, warfarin or glucocorticoid use. Serum was analyzed for total osteocalcin (tOC) and the ucOC fraction using the hydroxyapatite binding method. cOC, ucOC/tOC and cOC/tOC ratios were calculated. Reference intervals were established by polynomial quantile regression analysis. RESULTS The normal ranges for young men (≤30 years) were: tOC 17.9-56.8 ng/mL, ucOC 7.1-22.0 ng/mL, cOC 8.51-40.3 ng/mL (2.5th to 97.5th quantiles). Aging was associated with a "U" shaped pattern for tOC, cOC and ucOC levels. ucOC/tOC ratio was higher, while cOC/tOC ratio was lower in men of advanced age. Age explained ∼31%, while body mass index explained ∼4%, of the variance in the ratios. CONCLUSIONS We have defined normal reference ranges for the OC forms in Australian men and demonstrated that the OC ratios may be better measures, than the absolute values, to identify the age-related changes on OC in men. These ratios may be incorporated into future research and clinical trials, and their associations with prediction of events, such as fracture or diabetes risk, should be determined.
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Affiliation(s)
- Cassandra Smith
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, VIC, Australia; Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia
| | - Sarah Voisin
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, VIC, Australia
| | - Ahmed Al Saedi
- Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia; Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia
| | - Steven Phu
- Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia; Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia
| | - Tara Brennan-Speranza
- Department of Physiology and Bosch Institute for Medical Research, University of Sydney, New South Wales, Australia
| | - Lewan Parker
- Institute for Physical Activity and Nutrition (IPAN), Deakin University, Geelong, VIC, Australia
| | - Nir Eynon
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, VIC, Australia; Murdoch Childrens Research Institute, Melbourne, Australia
| | - Danielle Hiam
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, VIC, Australia
| | - Xu Yan
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, VIC, Australia
| | - David Scott
- Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia; School of Clinical Sciences at Monash Health, Monash University, Melbourne, VIC, Australia
| | - Lauren C Blekkenhorst
- School of Medical and Health Sciences, Edith Cowan University, Perth, Australia; Medical School, University of Western Australia, Perth, Australia
| | - Joshua R Lewis
- School of Medical and Health Sciences, Edith Cowan University, Perth, Australia; Medical School, University of Western Australia, Perth, Australia; Centre for Kidney Research, Children's Hospital at Westmead School of Public Health, Sydney Medical School, The University of Sydney, Sydney, Australia
| | - Ego Seeman
- University of Melbourne and the Department of Endocrinology, Austin Health and the Mary Mackillop Institute of Healthy Aging, Australian Catholic University, Melbourne, Australia
| | - Elizabeth Byrnes
- Department of Biochemistry, PathWest Laboratory Medicine, Queen Elizabeth II Medical Centre, Perth, Australia
| | - Leon Flicker
- Medical School, University of Western Australia, Perth, Australia; Western Australian Centre for Health & Ageing, University of Western Australia, Perth, Australia
| | - Gustavo Duque
- Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia; Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia
| | - Bu B Yeap
- Medical School, University of Western Australia, Perth, Australia; Department of Endocrinology and Diabetes, Fiona Stanley Hospital, Perth, Australia
| | - Itamar Levinger
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, VIC, Australia; Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia; Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia.
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Lewis JR, Brennan-Speranza TC, Levinger I, Byrnes E, Lim EM, Blekkenhorst LC, Sim M, Hodgson JM, Zhu K, Lim WH, Adams LA, Prince RL. Effects of calcium supplementation on circulating osteocalcin and glycated haemoglobin in older women. Osteoporos Int 2019; 30:2065-2072. [PMID: 31342138 DOI: 10.1007/s00198-019-05087-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 07/09/2019] [Indexed: 01/18/2023]
Abstract
UNLABELLED One year of calcium supplementation in older women led to modest reductions in total osteocalcin and undercarboxylated osteocalcin (ucOC), with no changes in muscle or fat mass, or glycated haemoglobin. Future studies should explore whether treatments with more profound effects of suppressing ucOC may lead to impaired glycaemic control. INTRODUCTION Total osteocalcin (TOC) is a marker of bone turnover, while its undercarboxylated form has beneficial effects on glucose metabolism in mice. This post hoc analysis of a randomised double-blind, placebo-controlled trial examined whether 1 year of calcium supplementation affected circulating TOC, undercarboxylated osteocalcin (ucOC) or glycated haemoglobin (HbA1c) in 1368 older community-dwelling women (mean age 75.2 ± 2.7 years). METHODS Women enrolled in the Calcium Intake Fracture Outcome Study trial (1998-2003) were supplemented with 1.2 g/d of elemental calcium (in the form of calcium carbonate) or placebo. Circulating TOC, ucOC and HbA1c was measured at 1 year (1999). RESULTS After 1 year of calcium supplementation, TOC and ucOC levels were 17% and 22% lower compared with placebo (mean 22.7 ± 9.1 vs. 27.3 ± 10.9 μg/L and 11.1 ± 4.9 vs. 13.0 ± 5.7 μg/L, both P < 0.001). Carboxylated osteocalcin/ucOC was 6% lower after calcium supplementation (P < 0.05). Despite this, no differences in HbA1c were observed (calcium, 5.2 ± 0.6 vs. placebo, 5.3 ± 0.8%; P = 0.08). Calcium supplementation did not affect BMI, whole body lean or fat mass. In exploratory analyses, total calcium (dietary and supplemental) was inversely related to TOC and ucOC, indicating calcium intake is an important dietary determinant of osteocalcin levels. CONCLUSION One year of calcium supplementation in older women led to modest reductions in TOC and ucOC, with no changes in muscle or fat mass, or HbA1c. Future studies should explore whether treatments with more profound effects of suppressing ucOC may lead to impaired glycaemic control.
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Affiliation(s)
- J R Lewis
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
- Medical School, University of Western Australia, Perth, Australia.
- Centre for Kidney Research, Children's Hospital at Westmead School of Public Health, Sydney Medical School, The University of Sydney, Sydney, Australia.
| | - T C Brennan-Speranza
- Department of Physiology, Bosch Institute for Medical Research, University of Sydney, Sydney, Australia
| | - I Levinger
- Institute of Health and Sport (IHES), Victoria University, Melbourne, Victoria, Australia
- Australian Institute for Musculoskeletal Science (AIMSS), Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia
| | - E Byrnes
- PathWest Laboratory Medicine, Sir Charles Gairdner Hospital, Perth, Australia
| | - E M Lim
- PathWest Laboratory Medicine, Sir Charles Gairdner Hospital, Perth, Australia
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Perth, Australia
| | - L C Blekkenhorst
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
| | - M Sim
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
- Medical School, University of Western Australia, Perth, Australia
| | - J M Hodgson
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
- Medical School, University of Western Australia, Perth, Australia
| | - K Zhu
- Medical School, University of Western Australia, Perth, Australia
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Perth, Australia
| | - W H Lim
- Medical School, University of Western Australia, Perth, Australia
- Department of Renal Medicine, Sir Charles Gairdner Hospital, Perth, Australia
| | - L A Adams
- Medical School, University of Western Australia, Perth, Australia
- Department of Hepatology, Sir Charles Gairdner Hospital, Nedlands, Australia
| | - R L Prince
- Medical School, University of Western Australia, Perth, Australia
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Perth, Australia
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Expression profile analysis of long non-coding RNA in skeletal muscle of osteoporosis by microarray and bioinformatics. J Biol Eng 2019; 13:50. [PMID: 31164921 PMCID: PMC6544974 DOI: 10.1186/s13036-019-0180-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/15/2019] [Indexed: 12/02/2022] Open
Abstract
Background Osteoporosis (OP) is a condition featured by bone mass loss and bone tissue microarchitectural alterations due to impaired tissue homeostasis favoring excessive bone resorption versus deposition. The trigger of such an impairment and the downstream molecular pathways involved are yet to be clarified. Long non-coding RNA (lncRNA) plays a role in gene transcription, protein expression and epigenetic regulation; and altered expression results in immune or metabolism related desease development. To determine whether lncRNAs are involved in osteoporosis, we analyzed the expression profile of lncRNAs and mRNAs in osteoporosis. Method Three pairs of osteoporosis patients (OP group) and healthy people controls (NC group) were screened by microarray. Quantitative polymerase chain reaction (qRT-PCR) was performed to confirm dysregulated lncRNA expressions in 5 pairs of OP and NC group tissues samples. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to construct the lncRNA-mRNA co-expression network. Result Through co-expression analysis, differently expressed transcripts were divided into modules, and lncRNAs were functionally annotated. We further analyzed the clinical significance of crucial lncRNAs from modules in public data. Finally, the expression of five lncRNAs, CUST_44695_PI430048170-GeneSymbol:CTA-384D8.35;CUST_39447_PI430048170,CUST_73298_PI430048170,CUST_108340_PI430048170,CUST_118927_PI430048170,this four lncRNAs have not been annotation genes and have not found GeneSymbols, and by quantitative RT-PCR, which may be associated with osteoporosis patients’ overall survival. Conclusion Analysis of this study revealed that dysregulated lncRNAs and mRNAs in osteoporosis patients and health people controls could affect the immune or metabolism system and musculoskeletal cell differentiation. The biological functions of those lncRNAs need to be further validated.
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Li G, Zhang L, Wang D, AIQudsy L, Jiang JX, Xu H, Shang P. Muscle-bone crosstalk and potential therapies for sarco-osteoporosis. J Cell Biochem 2019; 120:14262-14273. [PMID: 31106446 DOI: 10.1002/jcb.28946] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 04/15/2019] [Accepted: 04/18/2019] [Indexed: 12/17/2022]
Abstract
The nature of muscle-bone crosstalk has been historically considered to be only mechanical, where the muscle is the load applier while bone provides the attachment sites. However, this dogma has been challenged with the emerging notion that bone and muscle act as secretory endocrine organs affect the function of each other. Biochemical crosstalk occurs through myokines such as myostatin, irisin, interleukin (IL)-6, IL-7, IL-15, insulin-like growth factor-1, fibroblast growth factor (FGF)-2, and β-aminoisobutyric acid and through bone-derived factors including FGF23, prostaglandin E2 , transforming growth factor β, osteocalcin, and sclerostin. Aside from the biochemical and mechanical interaction, additional factors including aging, circadian rhythm, nervous system network, nutrition intake, and exosomes also have effects on bone-muscle crosstalk. Here, we summarize the current research progress in the area, which may be conductive to identify potential novel therapies for the osteoporosis and sarcopenia, especially when they develop in parallel.
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Affiliation(s)
- GuoBin Li
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Lan Zhang
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - DongEn Wang
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Luban AIQudsy
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas
| | - HuiYun Xu
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Peng Shang
- Research & Development Institute in Shenzhen, Northwestern Polytechnical University, Shenzhen, Guangdong, China
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Bonewald L. Use it or lose it to age: A review of bone and muscle communication. Bone 2019; 120:212-218. [PMID: 30408611 PMCID: PMC6360108 DOI: 10.1016/j.bone.2018.11.002] [Citation(s) in RCA: 118] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 11/03/2018] [Accepted: 11/03/2018] [Indexed: 12/21/2022]
Abstract
Until recently, it was assumed that the only interaction between muscle and bone is mechanical, that the muscle acts as a pulley and the bone as a lever to move the organism. A relatively new concept is that muscle, especially contracted muscle, acts as a secretory organ, regulating metabolism. An even newer concept is that bone, especially the osteocytes in bone, act as endocrine cells targeting other organs such as kidney and more recently, muscle. These two new concepts logically led to the third concept: that muscle and bone communicate via soluble factors. Crosstalk occurs through muscle factors such as myostatin, irisin, and a muscle metabolite, β-aminoisobutyric acid, BAIBA, and through bone factors such as osteocalcin, transforming growth factor beta, TGFβ, Prostaglandin E2, PGE2 and Wnts. Some of these factors have positive and some negative effects on the opposing tissue. One feature both bone and muscle have in common is that their tissues are mechanically loaded and many of their secreted factors are regulated by load. This mechanical loading, also known as exercise, has beneficial effects on many systems leading to the hypothesis that muscle and bone factors can be responsible for the beneficial effects of exercise. Many of the characteristics of aging and diseases associated with aging such as sarcopenia and osteoporosis and neurological conditions such as Alzheimer's disease and dementia, are delayed by exercise. This beneficial effect has been ascribed to increased blood flow increasing oxygen and nutrients, but could also be due to the secretome of the musculoskeletal system as outlined in this review.
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Zhu Y, Ma Y, Elefteriou F. Cortical bone is an extraneuronal site of norepinephrine uptake in adult mice. Bone Rep 2018; 9:188-198. [PMID: 30581894 PMCID: PMC6296164 DOI: 10.1016/j.bonr.2018.11.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 10/23/2018] [Accepted: 11/21/2018] [Indexed: 12/30/2022] Open
Abstract
The sympathetic nervous system is a major efferent pathway through which the central nervous system controls the function of peripheral organs. Genetic and pharmacologic evidence in mice indicated that stimulation of the β2 adrenergic receptor (β2AR) in osteoblasts promotes bone loss, leading to the paradigm that high sympathetic nervous activity is deleterious to bone mass. However, considerably less data exist to understand the putative impact of endogenous norepinephrine (NE), released by sympathetic nerves, on bone homeostasis. In this study, we investigated the in vivo expression and activity of the norepinephrine transporter (NET), a membrane pump known to actively uptake NE from the extracellular space in presynaptic neurons. Consistent with previously published in vitro data showing NET uptake activity in differentiated osteoblasts, we were able to detect active NET-specific NE uptake in the mouse cortical bone compartment in vivo. This uptake was the highest in young mice and accordingly with an age-related reduction in NET uptake, NE bone content increased whereas Net RNA and protein expression decreased with age. Histologically, NET expression in adult mouse bones was detected in osteocytes via immunofluorescence. Lastly, taking advantage of tissue-specific fluorescent reporter mice, we used CLARITY imaging and light sheet microscopy to visualize the 3D distribution of sympathetic fibers in whole mount preparations of bone tissues. These analyses allowed us to detect tyrosine hydroxylase (TH)-positive sympathetic nerve fibers penetrating the cortical bone, where NET+ osteocytes reside. Together, these in vitro results support the existence of an age-dependent extraneuronal and osteocytic function of NET with potential to buffer the bone catabolic action of endogenous NE released by sympathetic nerves in vivo.
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Affiliation(s)
- Yuantee Zhu
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, United States
- Department of Orthopedics, Baylor College of Medicine, Houston, TX, United States
| | - Yun Ma
- Department of Orthopedics, Baylor College of Medicine, Houston, TX, United States
| | - Florent Elefteriou
- Department of Orthopedics, Baylor College of Medicine, Houston, TX, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
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Bettis T, Kim BJ, Hamrick MW. Impact of muscle atrophy on bone metabolism and bone strength: implications for muscle-bone crosstalk with aging and disuse. Osteoporos Int 2018; 29:1713-1720. [PMID: 29777277 PMCID: PMC7861141 DOI: 10.1007/s00198-018-4570-1] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 03/28/2018] [Indexed: 02/07/2023]
Abstract
Bone fractures in older adults are often preceded by a loss of muscle mass and strength. Likewise, bone loss with prolonged bed rest, spinal cord injury, or with exposure to microgravity is also preceded by a rapid loss of muscle mass. Recent studies using animal models in the setting of hindlimb unloading or botulinum toxin (Botox) injection also reveal that muscle loss can induce bone loss. Moreover, muscle-derived factors such as irisin and leptin can inhibit bone loss with unloading, and knockout of catabolic factors in muscle such as the ubiquitin ligase Murf1 or the myokine myostatin can reduce osteoclastogenesis. These findings suggest that therapies targeting muscle in the setting of disuse atrophy may potentially attenuate bone loss, primarily by reducing bone resorption. These potential therapies not only include pharmacological approaches but also interventions such as whole-body vibration coupled with resistance exercise and functional electric stimulation of muscle.
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Affiliation(s)
- T Bettis
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Laney Walker Blvd. CB2915, Augusta, GA, 30912, USA
| | - B-J Kim
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Laney Walker Blvd. CB2915, Augusta, GA, 30912, USA
- ASAN Medical Center, College of Medicine, University of Ulsan, Seoul, Republic of Korea
| | - M W Hamrick
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Laney Walker Blvd. CB2915, Augusta, GA, 30912, USA.
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Odagaki N, Ishihara Y, Wang Z, Ei Hsu Hlaing E, Nakamura M, Hoshijima M, Hayano S, Kawanabe N, Kamioka H. Role of Osteocyte-PDL Crosstalk in Tooth Movement via SOST/Sclerostin. J Dent Res 2018; 97:1374-1382. [PMID: 29863952 DOI: 10.1177/0022034518771331] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Sclerostin (Scl) negatively regulates bone formation and favors bone resorption. Osteocytes, the cells responsible for mechanosensing, are known as the primary source of Scl and are a key regulator of bone remodeling through the induction of receptor activator of NF-κB ligand (RANKL). However, the spatiotemporal patterns of Scl in response to mechanical stimuli and their regulatory mechanisms remain unknown. We investigated the regulatory dynamics of the SOST/Scl expression generated by orthodontic tooth movement (OTM) in vivo and in vitro. In 8-wk-old male mice, coil springs were used to move the first molar mesially for 0, 1, 5, or 10 d. A regional histogram and the distribution patterns of the Scl expression showed that the Scl expression in the alveolar bone was increased on the compression side and peaked on day 5, with a gradual increase in the degree of significance. On day 10, the expression around the periodontal ligament (PDL)-alveolar bone boundary returned to the control level. Conversely, the expression of Scl on the tension side was only significantly decreased on day 1. Compressive force biphasically modulated the SOST/Scl expression in the isolated human PDL and thereby upregulated osteocytic SOST via paracrine activation in an osteocyte-PDL co-culture system designed to mimic OTM. This system did not affect the RANKL or OPG expression in osteocytes, suggesting that the bone resorption pathways are acted upon in a PDL-dependent and osteocyte-independent manner through RANKL/OPG signaling. Moreover, sclerostin neutralizing antibody significantly attenuated the upregulation of SOST that was induced by compressive force. In conclusion, our results provide evidence to support that factors secreted by the PDL, including SOST/Scl, control alveolar bone remodeling through osteocytic SOST/Scl in OTM.
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Affiliation(s)
- N Odagaki
- 1 Department of Orthodontics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Y Ishihara
- 2 Department of Orthodontics, Okayama University Hospital, Okayama, Japan
| | - Z Wang
- 1 Department of Orthodontics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - E Ei Hsu Hlaing
- 1 Department of Orthodontics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - M Nakamura
- 2 Department of Orthodontics, Okayama University Hospital, Okayama, Japan
| | - M Hoshijima
- 1 Department of Orthodontics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - S Hayano
- 1 Department of Orthodontics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - N Kawanabe
- 1 Department of Orthodontics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - H Kamioka
- 1 Department of Orthodontics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
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The temporospatial pattern of energy metabolism coordinates the interactions between the bones and other organ systems. J Oral Biosci 2018. [DOI: 10.1016/j.job.2017.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Abstract
PURPOSE OF REVIEW This review assembles recent understanding of the profound loss of muscle and bone in spinal cord injury (SCI). It is important to try to understand these changes, and the context in which they occur, because of their impact on the wellbeing of SC-injured individuals, and the urgent need for viable preventative therapies. RECENT FINDINGS Recent research provides new understanding of the effects of age and systemic factors on the response of bone to loading, of relevance to attempts to provide load therapy for bone in SCI. The rapidly growing dataset describing the biochemical crosstalk between bone and muscle, and the cell and molecular biology of myokines signalling to bone and osteokines regulating muscle metabolism and mass, is reviewed. The ways in which this crosstalk may be altered in SCI is summarised. Therapeutic approaches to the catabolic changes in muscle and bone in SCI require a holistic understanding of their unique mechanical and biochemical context.
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Affiliation(s)
- Jillian M Clark
- Discipline of Orthopaedics and Trauma, The University of Adelaide, North Terrace, Adelaide, South Australia, 5000, Australia.
| | - David M Findlay
- Discipline of Orthopaedics and Trauma, The University of Adelaide, North Terrace, Adelaide, South Australia, 5000, Australia
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Shen H, Lim C, Schwartz AG, Andreev-Andrievskiy A, Deymier AC, Thomopoulos S. Effects of spaceflight on the muscles of the murine shoulder. FASEB J 2017; 31:5466-5477. [PMID: 28821629 DOI: 10.1096/fj.201700320r] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 07/31/2017] [Indexed: 12/31/2022]
Abstract
Mechanical loading is necessary for the development and maintenance of the musculoskeletal system. Removal of loading via microgravity, paralysis, or bed rest leads to rapid loss of muscle mass and function; however, the molecular mechanisms that lead to these changes are largely unknown, particularly for the spaceflight (SF) microgravity environment. Furthermore, few studies have explored these effects on the shoulder, a dynamically stabilized joint with a large range of motion; therefore, we examined the effects of microgravity on mouse shoulder muscles for the 15-d Space Transportation System (STS)-131, 13-d STS-135, and 30-d Bion-M1 missions. Mice from STS missions were euthanized within 4 h after landing, whereas mice from the Bion-M1 mission were euthanized within 14 h after landing. The motion-generating deltoid muscle was more sensitive to microgravity than the joint-stabilizing rotator cuff muscles. Mice from the STS-131 mission exhibited reduced myogenic (Myf5 and -6) and adipogenic (Pparg, Cebpa, and Lep) gene expression, whereas either no change or an increased expression of these genes was observed in mice from the Bion-M1 mission. In summary, muscle responses to microgravity were muscle-type specific, short-duration SF caused dramatic molecular changes to shoulder muscles and responses to reloading upon landing were rapid.-Shen, H., Lim, C., Schwartz, A. G., Andreev-Andrievskiy, A., Deymier, A. C., Thomopoulos, S. Effects of spaceflight on the muscles of the murine shoulder.
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Affiliation(s)
- Hua Shen
- Department of Orthopaedic Surgery, Washington University, St. Louis, Missouri, USA
| | - Chanteak Lim
- Department of Orthopaedic Surgery, Washington University, St. Louis, Missouri, USA
| | - Andrea G Schwartz
- Department of Orthopaedic Surgery, Washington University, St. Louis, Missouri, USA
| | - Alexander Andreev-Andrievskiy
- Institute for Biomedical Problems, Russian Academy of Sciences, Moscow, Russia.,Biology Faculty, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Alix C Deymier
- Department of Orthopedic Surgery, Columbia University, New York, New York, USA
| | - Stavros Thomopoulos
- Department of Orthopedic Surgery, Columbia University, New York, New York, USA; .,Department of Biomedical Engineering, Columbia University, New York, New York, USA
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Abstract
PURPOSE OF REVIEW To discuss current knowledge on the role of connexins and pannexins in the musculoskeletal system. RECENT FINDINGS Connexins and pannexins are crucial for the development and maintenance of both bone and skeletal muscle. In bone, the presence of connexin and more recently of pannexin channels in osteoblasts, osteoclasts, and osteocytes has been described and shown to be essential for normal skeletal development and bone adaptation. In skeletal muscles, connexins and pannexins play important roles during development and regeneration through coordinated regulation of metabolic functions via cell-to-cell communication. Further, under pathological conditions, altered expression of these proteins can promote muscle atrophy and degeneration by stimulating inflammasome activity. In this review, we highlight the important roles of connexins and pannexins in the development, maintenance, and regeneration of musculoskeletal tissues, with emphasis on the mechanisms by which these molecules mediate chemical (e.g., ATP and prostaglandin E2) and physical (e.g., mechanical stimulation) stimuli that target the musculoskeletal system and their involvement in the pathophysiological changes in both genetic and acquired diseases.
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Affiliation(s)
- Lilian I Plotkin
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS5045, Indianapolis, IN, 46202, USA.
- Roudebush Veterans Administration Medical Center, Indianapolis, Indiana, USA.
- Indiana Center for Musculoskeletal Health, Indianapolis, Indiana, USA.
| | - Hannah M Davis
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS5045, Indianapolis, IN, 46202, USA
| | - Bruno A Cisterna
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Av. Alameda 340, Santiago, Chile
| | - Juan C Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Av. Alameda 340, Santiago, Chile.
- Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile.
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Buo AM, Tomlinson RE, Eidelman ER, Chason M, Stains JP. Connexin43 and Runx2 Interact to Affect Cortical Bone Geometry, Skeletal Development, and Osteoblast and Osteoclast Function. J Bone Miner Res 2017; 32:1727-1738. [PMID: 28419546 PMCID: PMC5550348 DOI: 10.1002/jbmr.3152] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 03/30/2017] [Accepted: 04/10/2017] [Indexed: 12/30/2022]
Abstract
The coupling of osteoblasts and osteocytes by connexin43 (Cx43) gap junctions permits the sharing of second messengers that coordinate bone cell function and cortical bone acquisition. However, details of how Cx43 converts shared second messengers into signals that converge onto essential osteogenic processes are incomplete. Here, we use in vitro and in vivo methods to show that Cx43 and Runx2 functionally interact to regulate osteoblast gene expression and proliferation, ultimately affecting cortical bone properties. Using compound hemizygous mice for the Gja1 (Cx43) and Runx2 genes, we observed a skeletal phenotype not visible in wild-type or singly hemizygous animals. Cortical bone analysis by micro-computed tomography (μCT) revealed that 8-week-old male, compound Gja1+/- Runx2+/- mice have a marked increase in cross-sectional area, endosteal and periosteal bone perimeter, and an increase in porosity compared to controls. These compound Gja1+/- Runx2+/- mice closely approximate the cortical bone phenotypes seen in osteoblast-specific Gja1-conditional knockout models. Furthermore, μCT analysis of skulls revealed an altered interparietal bone geometry in compound hemizygotes. Consistent with this finding, Alizarin red/Alcian blue staining of 2-day-old Gja1+/- Runx2+/- neonates showed a hypomorphic interparietal bone, an exacerbation of the open fontanelles, and a further reduction in the hypoplastic clavicles compared to Runx2+/- neonates. Expression of osteoblast genes, including osteocalcin, osterix, periostin, and Hsp47, was markedly reduced in tibial RNA extracts from compound hemizygous mice, and osteoblasts from compound hemizygous mice exhibited increased proliferative capacity. Further, the reduced osteocalcin expression and hyperproliferative nature of osteoblasts from Cx43 deficient mice was rescued by Runx2 expression. In summary, these findings provide evidence that Cx43 and Runx2 functionally intersect in vivo to regulate cortical bone properties and affect osteoblast differentiation and proliferation, and likely contributes to aspects of the skeletal phenotype of Cx43 conditional knockout mice. © 2017 American Society for Bone and Mineral Research.
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Affiliation(s)
- Atum M Buo
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Ryan E Tomlinson
- Department of Orthopedic Surgery, Johns Hopkins University, Baltimore, MD, USA
| | - Eric R Eidelman
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Max Chason
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Joseph P Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA
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40
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Ward LM, Kinnett K, Bonewald L. Proceedings of a Parent Project Muscular Dystrophy Bone Health Workshop: Morbidity due to osteoporosis in DMD: The Path Forward May 12-13, 2016, Bethesda, Maryland, USA. Neuromuscul Disord 2017; 28:64-76. [PMID: 28756052 DOI: 10.1016/j.nmd.2017.05.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 05/04/2017] [Accepted: 05/11/2017] [Indexed: 10/19/2022]
Affiliation(s)
- Leanne M Ward
- Division of Endocrinology and Metabolism, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, ON, Canada.
| | - Kathi Kinnett
- Parent Project Muscular Dystrophy, Middletown, OH, USA
| | - Lynda Bonewald
- Indiana Center for Musculoskeletal Health, Departments of Anatomy and Cell Biology and Orthopaedic Surgery, Indiana University, Indianapolis, IN, USA
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41
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McGee-Lawrence ME, Wenger KH, Misra S, Davis CL, Pollock NK, Elsalanty M, Ding K, Isales CM, Hamrick MW, Wosiski-Kuhn M, Arounleut P, Mattson MP, Cutler RG, Yu JC, Stranahan AM. Whole-Body Vibration Mimics the Metabolic Effects of Exercise in Male Leptin Receptor-Deficient Mice. Endocrinology 2017; 158:1160-1171. [PMID: 28323991 PMCID: PMC5460837 DOI: 10.1210/en.2016-1250] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 02/02/2017] [Indexed: 01/12/2023]
Abstract
Whole-body vibration (WBV) has gained attention as a potential exercise mimetic, but direct comparisons with the metabolic effects of exercise are scarce. To determine whether WBV recapitulates the metabolic and osteogenic effects of physical activity, we exposed male wild-type (WT) and leptin receptor-deficient (db/db) mice to daily treadmill exercise (TE) or WBV for 3 months. Body weights were analyzed and compared with WT and db/db mice that remained sedentary. Glucose and insulin tolerance testing revealed comparable attenuation of hyperglycemia and insulin resistance in db/db mice following TE or WBV. Both interventions reduced body weight in db/db mice and normalized muscle fiber diameter. TE or WBV also attenuated adipocyte hypertrophy in visceral adipose tissue and reduced hepatic lipid content in db/db mice. Although the effects of leptin receptor deficiency on cortical bone structure were not eliminated by either intervention, exercise and WBV increased circulating levels of osteocalcin in db/db mice. In the context of increased serum osteocalcin, the modest effects of TE and WBV on bone geometry, mineralization, and biomechanics may reflect subtle increases in osteoblast activity in multiple areas of the skeleton. Taken together, these observations indicate that WBV recapitulates the effects of exercise on metabolism in type 2 diabetes.
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MESH Headings
- Adipocytes/metabolism
- Adipocytes/pathology
- Animals
- Body Weight
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/therapy
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/therapy
- Energy Metabolism/genetics
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscular Atrophy/genetics
- Muscular Atrophy/metabolism
- Muscular Atrophy/prevention & control
- Physical Conditioning, Animal/physiology
- Receptors, Leptin/genetics
- Vibration/therapeutic use
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Affiliation(s)
- Meghan E. McGee-Lawrence
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Karl H. Wenger
- Department of Orthopedic Surgery, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Sudipta Misra
- Department of Pediatrics, Gastroenterology Division, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Catherine L. Davis
- Georgia Prevention Institute, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
- Physiology Department, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Norman K. Pollock
- Georgia Prevention Institute, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
- Physiology Department, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Mohammed Elsalanty
- Department of Oral Biology, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Kehong Ding
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Carlos M. Isales
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Mark W. Hamrick
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Marlena Wosiski-Kuhn
- Physiology Department, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Phonepasong Arounleut
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Mark P. Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland 21224
| | - Roy G. Cutler
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland 21224
| | - Jack C. Yu
- Department of Surgery, Plastic Surgery Division, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Alexis M. Stranahan
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
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42
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Wood CL, Pajevic PD, Gooi JH. Osteocyte secreted factors inhibit skeletal muscle differentiation. Bone Rep 2017; 6:74-80. [PMID: 28377986 PMCID: PMC5365311 DOI: 10.1016/j.bonr.2017.02.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 02/13/2017] [Accepted: 02/28/2017] [Indexed: 01/02/2023] Open
Abstract
It is generally accepted that bone and muscle possess the capacity to act in an autocrine, paracrine, or endocrine manner, with a growing body of evidence that suggests muscle can secrete muscle specific cytokines or "myokines", which influence bone metabolism. However, there has been little investigation into the identity of bone specific cytokines that modulate skeletal muscle differentiation and function. This study aimed to elucidate the influence of osteocytes on muscle progenitor cells in vitro and to identify potential bone specific cytokines or "osteokines". We treated C2C12 myoblasts with media collected from differentiated osteocytes (Ocy454 cells) grown in 3D, either under static or fluid flow culture conditions (2 dynes/cm2). C2C12 differentiation was significantly inhibited with a 75% reduction in the number of myofibers formed. mRNA analysis revealed a significant reduction in the expression of myogenic regulatory genes. Cytokine array analysis on the conditioned media demonstrated that osteocytes produce a significant number of cytokines "osteokines" capable of inhibiting myogenesis. Furthermore, we demonstrated that when osteocytes are mechanically activated they induce a greater inhibitory effect on myogenesis compared to a static state. Lastly, we identified the downregulation of numerous cytokines, including Il-6, Il-13, Il-1β, MIP-1α, and Cxcl9, involved in myogenesis, which may lead to future investigation of the role "osteokines" play in musculoskeletal health and pathology.
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Affiliation(s)
- Charles L Wood
- Department of Medicine, St. Vincent's Hospital Melbourne, The University of Melbourne, Melbourne, VIC 3065, Australia
| | - Paola Divieti Pajevic
- Molecular and Cell Biology, Goldman School of Dental Medicine, Boston University, Boston, MA, United States
| | - Jonathan H Gooi
- Department of Medicine, St. Vincent's Hospital Melbourne, The University of Melbourne, Melbourne, VIC 3065, Australia
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Abstract
When normal physiologic functions go awry, disorders and disease occur. This is universal; even for the osteocyte, a cell embedded within the mineralized matrix of bone. It was once thought that this cell was simply a placeholder in bone. Within the last decade, the number of studies of osteocytes has increased dramatically, leading to the discovery of novel functions of these cells. With the discovery of novel physiologic functions came the discoveries of how these cells can also be responsible for not only bone diseases and disorders, but also those of the kidney, heart, and potentially muscle.
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Affiliation(s)
- Lynda F Bonewald
- Indiana Center for Musculoskeletal Health, VanNuys Medical Science Building, MS 5055, 635 Barnhill Drive, Indianapolis, IN 46202, USA; Department of Anatomy and Cell Biology, VanNuys Medical Science Building, MS 5035, Indianapolis, IN 46202, USA; Department of Orthopaedic Surgery, 1120 West Michigan Street, Suite 600, Indianapolis, IN 46202, USA.
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Abstract
PURPOSE OF REVIEW The role of bone-derived factors in regulation of skeletal muscle function is an important emerging aspect of research into bone-muscle crosstalk. Implications for this area of research are far reaching and include understanding skeletal muscle weakness in cancer, osteoporosis, cachexia, rare diseases of bone, and aging. RECENT FINDINGS Recent research shows that bone-derived factors can lead to changes in the skeletal muscle. These changes can either be anabolic or catabolic, and we focus this review on the role of TGFβ in driving oxidative stress and skeletal muscle weakness in the setting of osteolytic cancer in the bone. The bone is a preferred site for breast cancer metastasis and leads to pathological bone loss. Osteolytic cancer in the bone leads to release of TGFβ from the bone via osteoclast-mediated bone destruction. Our appreciation of crosstalk between the muscle and bone has recently expanded beyond mechanical force-driven events to encompass a variety of signaling factors originating in one tissue and communicating to the other. This review summarizes some previously known mediators of bone-to-muscle signaling and also recent work identifying a new role for bone-derived TGFβ as a cause of skeletal muscle weakness in the setting of osteolytic cancer in the bone. Multiple points of potential therapeutic intervention are discussed.
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Affiliation(s)
- Jenna N Regan
- Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Trupti Trivedi
- Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Theresa A Guise
- Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - David L Waning
- The Pennsylvania State University College of Medicine, 500 University Drive, H166, Rm C4710E, Hershey, PA, 17033, USA.
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45
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Bonnet N. Bone-Derived Factors: A New Gateway to Regulate Glycemia. Calcif Tissue Int 2017; 100:174-183. [PMID: 27832316 DOI: 10.1007/s00223-016-0210-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 11/02/2016] [Indexed: 01/26/2023]
Abstract
Type 2 diabetes mellitus (T2DM) and osteoporosis are two major disorders which prevalence increases with aging and is predicted to worsen in the coming years. Preclinical investigations suggest common mechanisms implicated in the pathogenesis of both disorders. Recent evidence has established that there is a clear link between glucose and bone metabolism. The emergence of bone as an endocrine regulator through FGF23 and osteocalcin has led to the re-evaluation of the role of bone cells and bone-derived factors in the development of metabolic diseases such as T2DM. The development of bone morphogenetic proteins, fibroblast growth factor 23, and osteoprotegerin-deficient mice has allowed to elucidate their role in bone homeostasis, as well as revealed their potential important function in glucose homeostasis. This review proposes emerging perspectives for several bone-derived factors that may regulate glycemia through the activation or inhibition of bone remodeling or directly by regulating function of key organs such as pancreatic beta cell proliferation, insulin expression and secretion, storage and release of glucose from the liver, skeletal muscle contraction, and browning of the adipose tissue. Connections between organs including bone-derived factors should further be explored to understand the pathophysiology of glucose metabolism and diabetes.
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Affiliation(s)
- Nicolas Bonnet
- Division of Bone Diseases, Department of Internal Medicine Specialties, Geneva University Hospitals and Faculty of Medicine, 64 Av de la Roseraie, 1205, Geneva 14, Switzerland.
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46
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Shea MK, Dawson-Hughes B, Gundberg CM, Booth SL. Reducing Undercarboxylated Osteocalcin With Vitamin K Supplementation Does Not Promote Lean Tissue Loss or Fat Gain Over 3 Years in Older Women and Men: A Randomized Controlled Trial. J Bone Miner Res 2017; 32:243-249. [PMID: 27604070 PMCID: PMC5292074 DOI: 10.1002/jbmr.2989] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 08/24/2016] [Accepted: 09/02/2016] [Indexed: 01/06/2023]
Abstract
Osteocalcin (OC) is a vitamin K-dependent protein synthesized during bone formation. Mice injected with the undercarboxylated form of OC (ucOC) had more skeletal muscle mass and less fat mass than sham-treated controls, suggesting a unique metabolic role for ucOC. UcOC decreases in response to vitamin K supplementation. Our objective was to determine the effect of reducing ucOC on change in lean tissue and fat mass in older community-dwelling adults (n = 401, mean ± SD 69 ± 6 years) using data from a randomized controlled trial of vitamin K supplementation. Over 3 years, serum ucOC was reduced by 58% in women and by 61% in men randomized to vitamin K, whereas in the control group, ucOC decreased by 1% in women and 4% in men (supplementation*time p < 0.001 in men and women). However, there were no differences in the change in appendicular lean mass (calculated as arm lean mass + leg lean mass) or total body fat mass between women randomized to vitamin K and control over 3 years (supplementation*time p values all ≥ 0.18) or between men randomized to vitamin K and control (supplementation*time p values all ≥ 0.54). Consistent with these findings, ucOC was not associated cross-sectionally with appendicular lean mass or fat mass in men or women after adjustment for total OC at baseline (all p ≥ 0.12). These findings indicate the undercarboxylated form of OC is not implicated in age-related changes in skeletal muscle or adipose tissue mass in older community-dwelling adults. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- M Kyla Shea
- USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
| | - Bess Dawson-Hughes
- USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
| | | | - Sarah L Booth
- USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
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47
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Huovinen V, Ivaska KK, Kiviranta R, Bucci M, Lipponen H, Sandboge S, Raiko J, Eriksson JG, Parkkola R, Iozzo P, Nuutila P. Bone mineral density is increased after a 16-week resistance training intervention in elderly women with decreased muscle strength. Eur J Endocrinol 2016; 175:571-582. [PMID: 27634943 DOI: 10.1530/eje-16-0521] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Revised: 08/26/2016] [Accepted: 09/15/2016] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Non-pharmacological interventions are important in reducing risk for osteoporotic fractures. We investigated the effects of a 16-week individualized resistance training intervention on bone mineral density (BMD), bone turnover markers and 10-year relative risk (RR) for osteoporotic fracture. DESIGN Interventional study with a follow-up. METHODS In total, 37 elderly women (mean age 71.9 ± 3.1 years) with decreased muscle strength participated in the resistance training intervention three times per week with 60 min per session for 16 weeks under the supervision of a licensed physiotherapist. Total hip BMD with quantitative CT, bone markers (sclerostin, osteocalcin, CTX, PINP, IGF-1, 25(OH)-D) and 10-year RR for osteoporotic fracture were measured at baseline, post-intervention and at 1-year follow-up after the end of the intervention. Eleven age- and sex-matched controls did not participate in the intervention but were studied at baseline and at 1-year follow-up. RESULTS Resistance training seemed to increase total hip BMD by 6% (P = 0.005). Sclerostin (P < 0.001) and total osteocalcin (P = 0.04) increased while other bone markers remained unchanged. A 10-year RR for major osteoporotic and hip fracture remained unchanged. At follow-up total hip BMD (P < 0.001) decreased back to the baseline level with a simultaneous decrease in serum sclerostin (P = 0.045), CTX (P < 0.001) and an increase in 25(OH)-D (P < 0.001), 10-year RR for major osteoporotic (P = 0.002) and hip fracture (P = 0.01). CONCLUSIONS Our findings suggest an important role of continuous supervised resistance training for the prevention of osteoporotic fractures in elderly women with decreased muscle strength.
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Affiliation(s)
- Ville Huovinen
- Turku PET CentreUniversity of Turku, Turku, Finland
- Department of RadiologyUniversity of Turku and Turku University Hospital, Turku, Finland
| | - Kaisa K Ivaska
- Department of Cell Biology and AnatomyInstitute of Biomedicine, University of Turku, Turku, Finland
| | - Riku Kiviranta
- Department of EndocrinologyTurku University Hospital, Turku, Finland
- Departments of Medicine and Medical Biochemistry and GeneticsUniversity of Turku, Turku, Finland
| | - Marco Bucci
- Turku PET CentreUniversity of Turku, Turku, Finland
| | | | - Samuel Sandboge
- Folkhälsan Research CentreHelsinki, Finland
- Department of Chronic Disease PreventionNational Institute for Health and Welfare, Helsinki, Finland
| | - Juho Raiko
- Turku PET CentreUniversity of Turku, Turku, Finland
| | - Johan G Eriksson
- Folkhälsan Research CentreHelsinki, Finland
- Department of Chronic Disease PreventionNational Institute for Health and Welfare, Helsinki, Finland
- Department of General Practice and Primary Health CareUniversity of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Riitta Parkkola
- Turku PET CentreUniversity of Turku, Turku, Finland
- Department of RadiologyUniversity of Turku and Turku University Hospital, Turku, Finland
| | - Patricia Iozzo
- Turku PET CentreUniversity of Turku, Turku, Finland
- Institute of Clinical PhysiologyNational Research Council (CNR), Pisa, Italy
| | - Pirjo Nuutila
- Turku PET CentreUniversity of Turku, Turku, Finland
- Department of EndocrinologyTurku University Hospital, Turku, Finland
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48
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Lin X, Hanson E, Betik AC, Brennan-Speranza TC, Hayes A, Levinger I. Hindlimb Immobilization, But Not Castration, Induces Reduction of Undercarboxylated Osteocalcin Associated With Muscle Atrophy in Rats. J Bone Miner Res 2016; 31:1967-1978. [PMID: 27291707 DOI: 10.1002/jbmr.2884] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 06/01/2016] [Accepted: 06/04/2016] [Indexed: 11/10/2022]
Abstract
Undercarboxylated osteocalcin (ucOC) has been implicated in skeletal muscle insulin sensitivity and function. However, whether muscle mass and strength loss in atrophic conditions is related to a reduction in ucOC is not clear. We hypothesized that both immobilization and testosterone depletion would lead to reductions in ucOC, associated with not only the degree of muscle atrophy but also changes to atrophy signaling pathway(s) in male rats. We subjected 8-week-old male Fischer (F344) rats to 7 days of hindlimb immobilization 10 days after castration surgery. Hindlimb immobilization, but not castration, resulted in a significant reduction in ucOC (30%) and lower ucOC was correlated with the degree of muscle loss and muscle weakness. ucOC levels, the expression of ucOC-sensitive receptor G protein-coupled receptor, class C, group 6, member A (GPRC6A), as well as the activity of extracellular signal-regulated kinase (ERK) and 5' adenosine monophosphate-activated protein kinase (AMPK) were associated with the expression and activity of a number of proteins in the mammalian target of rapamycin complex 1 (mTORC1) and Forkhead Box O (FOXO) signaling pathways in a muscle type-specific manner. These data suggest that ucOC may have other effects on skeletal muscle in addition to its insulin sensitizing effect. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- Xuzhu Lin
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Australia
| | - Erik Hanson
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Australia.,College of Health and Biomedicine, Victoria University, Melbourne, Australia
| | - Andrew C Betik
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Australia.,College of Health and Biomedicine, Victoria University, Melbourne, Australia
| | - Tara C Brennan-Speranza
- Department of Physiology and Bosch Institute for Medical Research, University of Sydney, Australia
| | - Alan Hayes
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Australia.,College of Health and Biomedicine, Victoria University, Melbourne, Australia.,Australian Institute for Musculoskeletal Science, Western Health, Melbourne, Australia
| | - Itamar Levinger
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Australia
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49
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Laurent MR, Dubois V, Claessens F, Verschueren SMP, Vanderschueren D, Gielen E, Jardí F. Muscle-bone interactions: From experimental models to the clinic? A critical update. Mol Cell Endocrinol 2016; 432:14-36. [PMID: 26506009 DOI: 10.1016/j.mce.2015.10.017] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/13/2015] [Accepted: 10/20/2015] [Indexed: 02/06/2023]
Abstract
Bone is a biomechanical tissue shaped by forces from muscles and gravitation. Simultaneous bone and muscle decay and dysfunction (osteosarcopenia or sarco-osteoporosis) is seen in ageing, numerous clinical situations including after stroke or paralysis, in neuromuscular dystrophies, glucocorticoid excess, or in association with vitamin D, growth hormone/insulin like growth factor or sex steroid deficiency, as well as in spaceflight. Physical exercise may be beneficial in these situations, but further work is still needed to translate acceptable and effective biomechanical interventions like vibration therapy from animal models to humans. Novel antiresorptive and anabolic therapies are emerging for osteoporosis as well as drugs for sarcopenia, cancer cachexia or muscle wasting disorders, including antibodies against myostatin or activin receptor type IIA and IIB (e.g. bimagrumab). Ideally, increasing muscle mass would increase muscle strength and restore bone loss from disuse. However, the classical view that muscle is unidirectionally dominant over bone via mechanical loading is overly simplistic. Indeed, recent studies indicate a role for neuronal regulation of not only muscle but also bone metabolism, bone signaling pathways like receptor activator of nuclear factor kappa-B ligand (RANKL) implicated in muscle biology, myokines affecting bone and possible bone-to-muscle communication. Moreover, pharmacological strategies inducing isolated myocyte hypertrophy may not translate into increased muscle power because tendons, connective tissue, neurons and energy metabolism need to adapt as well. We aim here to critically review key musculoskeletal molecular pathways involved in mechanoregulation and their effect on the bone-muscle unit as a whole, as well as preclinical and emerging clinical evidence regarding the effects of sarcopenia therapies on osteoporosis and vice versa.
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Affiliation(s)
- Michaël R Laurent
- Gerontology and Geriatrics, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Centre for Metabolic Bone Diseases, University Hospitals Leuven, 3000 Leuven, Belgium.
| | - Vanessa Dubois
- Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Frank Claessens
- Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Sabine M P Verschueren
- Research Group for Musculoskeletal Rehabilitation, Department of Rehabilitation Science, KU Leuven, 3000 Leuven, Belgium
| | - Dirk Vanderschueren
- Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Evelien Gielen
- Gerontology and Geriatrics, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Centre for Metabolic Bone Diseases, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Ferran Jardí
- Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
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50
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Shen C, Kim MR, Noh JM, Kim SJ, Ka SO, Kim JH, Park BH, Park JH. Glucocorticoid Suppresses Connexin 43 Expression by Inhibiting the Akt/mTOR Signaling Pathway in Osteoblasts. Calcif Tissue Int 2016; 99:88-97. [PMID: 26914606 DOI: 10.1007/s00223-016-0121-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 02/15/2016] [Indexed: 11/25/2022]
Abstract
The inhibition of proliferation or functional alteration of osteoblasts by glucocorticoids (GCs) has been recognized as an important etiology of GC-induced osteoporosis (GIO). Connexin 43 (Cx43) is the most abundant connexin isoform in bone cells and plays important roles in bone remodeling. Despite the important role of Cx43 in bone homeostasis and the prevalence of GIO, the direct action of GCs on Cx43 expression in osteoblasts has been poorly described. The aim of the present study was to evaluate how GCs affect Cx43 expression in osteoblasts. Dexamethasone (Dex) treatment decreased expression of Cx43 RNA and protein in MC3T3-E1 mouse osteoblastic cells. Reduction of Cx43 expression by Dex was dependent on the glucocorticoid receptor (GR), as it was abolished by pretreatment with a GR blocker. Treatment with PTH (1-34), a medication used for GIO management, counteracted the suppression of Cx43 by Dex. Akt or mTOR signaling modulators revealed the involvement of the Akt/mTOR signaling pathway in Dex-induced reduction of Cx43 expression. Moreover, overexpression of Cx43 significantly attenuated Dex-inhibited cell viability and proliferation, as evidenced by MTT and bromodeoxyuridine (BrdU) incorporation assay of MC3T3-E1 cells. To account for possible species or cell type differences, human primary osteoblasts were treated with Dex and similar downregulation of Cx43 by Dex was observed. In addition, immunofluorescent staining for Cx43 further demonstrated an apparent decrease in Dex-treated human osteoblasts, while analysis of lucifer yellow propagation revealed reduced gap junction intercellular communication by Dex. Collectively, these findings indicate that GCs suppress Cx43 expression in osteoblasts via GR and the Akt/mTOR signaling pathway and overexpression of Cx43 may, at least in part, rescue osteoblasts from GC-induced reductions in proliferation.
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Affiliation(s)
- Chen Shen
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Chonbuk National University Medical School, Geonji-Ro 20, Deokjin-Gu, Jeonju, 561-712, Republic of Korea
| | - Mi Ran Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Chonbuk National University Medical School, Geonji-Ro 20, Deokjin-Gu, Jeonju, 561-712, Republic of Korea
| | - Jeong Mi Noh
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Chonbuk National University Medical School, Geonji-Ro 20, Deokjin-Gu, Jeonju, 561-712, Republic of Korea
| | - Su Jin Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Chonbuk National University Medical School, Geonji-Ro 20, Deokjin-Gu, Jeonju, 561-712, Republic of Korea
| | - Sun-O Ka
- Department of Internal Medicine, Presbyterian Medical Center, Jeonju, Republic of Korea
| | - Ji Hye Kim
- Department of Biochemistry, Chonbuk National University Medical School, Jeonju, Republic of Korea
| | - Byung-Hyun Park
- Department of Internal Medicine, Presbyterian Medical Center, Jeonju, Republic of Korea
| | - Ji Hyun Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Chonbuk National University Medical School, Geonji-Ro 20, Deokjin-Gu, Jeonju, 561-712, Republic of Korea.
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