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Smith C, Lin X, Parker L, Yeap BB, Hayes A, Levinger I. The role of bone in energy metabolism: A focus on osteocalcin. Bone 2024; 188:117238. [PMID: 39153587 DOI: 10.1016/j.bone.2024.117238] [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: 04/08/2024] [Revised: 08/06/2024] [Accepted: 08/14/2024] [Indexed: 08/19/2024]
Abstract
Understanding the mechanisms involved in whole body glucose regulation is key for the discovery of new treatments for type 2 diabetes (T2D). Historically, glucose regulation was largely focused on responses to insulin and glucagon. Impacts of incretin-based therapies, and importance of muscle mass, are also highly relevant. Recently, bone was recognized as an endocrine organ, with several bone proteins, known as osteokines, implicated in glucose metabolism through their effects on the liver, skeletal muscle, and adipose tissue. Research efforts mostly focused on osteocalcin (OC) as a leading example. This review will provide an overview on this role of bone by discussing bone turnover markers (BTMs), the receptor activator of nuclear factor kB ligand (RANKL), osteoprotegerin (OPG), sclerostin (SCL) and lipocalin 2 (LCN2), with a focus on OC. Since 2007, some, but not all, research using mostly OC genetically modified animal models suggested undercarboxylated (uc) OC acts as a hormone involved in energy metabolism. Most data generated from in vivo, ex vivo and in vitro models, indicate that exogenous ucOC administration improves whole-body and skeletal muscle glucose metabolism. Although data in humans are generally supportive, findings are often discordant likely due to methodological differences and observational nature of that research. Overall, evidence supports the concept that bone-derived factors are involved in energy metabolism, some having beneficial effects (ucOC, OPG) others negative (RANKL, SCL), with the role of some (LCN2, other BTMs) remaining unclear. Whether the effect of osteokines on glucose regulation is clinically significant and of therapeutic value for people with insulin resistance and T2D remains to be confirmed.
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Affiliation(s)
- Cassandra Smith
- Nutrition & Health Innovation Research Institute, School of Health and Medical Sciences, Edith Cowan University, Perth, Western Australia, Australia; Medical School, The University of Western Australia, Perth, Western Australia, Australia; Institute for Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia; Australian Institute for Musculoskeletal Science (AIMSS), Victoria University and Western Health, St Albans, VIC, Australia
| | - Xuzhu Lin
- Centre for Cancer Research, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Lewan Parker
- Institute for Physical Activity and Nutrition (IPAN), Deakin University, Geelong, VIC, Australia
| | - Bu B Yeap
- Medical School, The University of Western Australia, Perth, Western Australia, Australia; Department of Endocrinology and Diabetes, Fiona Stanley Hospital, Perth, Australia
| | - Alan Hayes
- Institute for Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia; Australian Institute for Musculoskeletal Science (AIMSS), Victoria University and Western Health, St Albans, VIC, Australia; Department of Medicine - Western Health, The University of Melbourne, Footscray, VIC, Australia
| | - Itamar Levinger
- Institute for Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia; Australian Institute for Musculoskeletal Science (AIMSS), Victoria University and Western Health, St Albans, VIC, Australia; Department of Medicine - Western Health, The University of Melbourne, Footscray, VIC, Australia.
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Martiniakova M, Biro R, Kovacova V, Babikova M, Zemanova N, Mondockova V, Omelka R. Current knowledge of bone-derived factor osteocalcin: its role in the management and treatment of diabetes mellitus, osteoporosis, osteopetrosis and inflammatory joint diseases. J Mol Med (Berl) 2024; 102:435-452. [PMID: 38363329 PMCID: PMC10963459 DOI: 10.1007/s00109-024-02418-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 12/21/2023] [Accepted: 01/10/2024] [Indexed: 02/17/2024]
Abstract
Osteocalcin (OC) is the most abundant non-collagenous and osteoblast-secreted protein in bone. It consists of two forms such as carboxylated OC (cOC) and undercarboxylated OC (ucOC). While cOC promotes bone mineralization and increases bone strength, ucOC is regarded an endocrinologically active form that may have several functions in multiple end organs and tissues. Total OC (tOC) includes both of these forms (cOC and ucOC) and is considered a marker of bone turnover in clinical settings. Most of the data on OC is limited to preclinical studies and therefore may not accurately reflect the situation in clinical conditions. For the stated reason, the aim of this review was not only to summarize current knowledge of all forms of OC and characterize its role in diabetes mellitus, osteoporosis, osteopetrosis, inflammatory joint diseases, but also to provide new interpretations of its involvement in the management and treatment of aforementioned diseases. In this context, special emphasis was placed on available clinical trials. Significantly lower levels of tOC and ucOC could be associated with the risk of type 2 diabetes mellitus. On the contrary, tOC level does not seem to be a good indicator of high bone turnover status in postmenopausal osteoporosis, osteoarthritis and rheumatoid arthritis. The associations between several pharmacological drugs used to treat all disorders mentioned above and OC levels have also been provided. From this perspective, OC may serve as a medium through which certain medications can influence glucose metabolism, body weight, adiponectin secretion, and synovial inflammation.
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Affiliation(s)
- Monika Martiniakova
- Department of Zoology and Anthropology, Faculty of Natural Sciences and Informatics, Constantine the Philosopher University in Nitra, Tr. A. Hlinku 1, 949 01, Nitra, Slovakia
| | - Roman Biro
- Department of Zoology and Anthropology, Faculty of Natural Sciences and Informatics, Constantine the Philosopher University in Nitra, Tr. A. Hlinku 1, 949 01, Nitra, Slovakia
| | - Veronika Kovacova
- Department of Zoology and Anthropology, Faculty of Natural Sciences and Informatics, Constantine the Philosopher University in Nitra, Tr. A. Hlinku 1, 949 01, Nitra, Slovakia
| | - Martina Babikova
- Department of Botany and Genetics, Faculty of Natural Sciences and Informatics, Constantine the Philosopher University in Nitra, Tr. A. Hlinku 1, 949 01, Nitra, Slovakia
| | - Nina Zemanova
- Department of Botany and Genetics, Faculty of Natural Sciences and Informatics, Constantine the Philosopher University in Nitra, Tr. A. Hlinku 1, 949 01, Nitra, Slovakia
| | - Vladimira Mondockova
- Department of Botany and Genetics, Faculty of Natural Sciences and Informatics, Constantine the Philosopher University in Nitra, Tr. A. Hlinku 1, 949 01, Nitra, Slovakia
| | - Radoslav Omelka
- Department of Botany and Genetics, Faculty of Natural Sciences and Informatics, Constantine the Philosopher University in Nitra, Tr. A. Hlinku 1, 949 01, Nitra, Slovakia.
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Zheng WB, Hu J, Zhao DC, Zhou BN, Wang O, Jiang Y, Xia WB, Xing XP, Li M. The role of osteocalcin in regulation of glycolipid metabolism and muscle function in children with osteogenesis imperfecta. Front Endocrinol (Lausanne) 2022; 13:898645. [PMID: 35983511 PMCID: PMC9378831 DOI: 10.3389/fendo.2022.898645] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 07/05/2022] [Indexed: 12/04/2022] Open
Abstract
OBJECTIVE Osteoblasts are discovered to secrete hormones with endocrine effects on metabolism, and osteocalcin (OC) is the most abundant non-collagenous protein in bone. We investigate the relationship between serum OC levels and glycolipid metabolism and muscle function in children with osteogenesis imperfecta (OI). METHODS A total of 225 children with OI and 80 healthy controls matched in age and gender were included in this single center study. Serum levels of fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TC), low- and high-density lipoprotein cholesterol (LDL-C, HDL-C) were measured by automated analyzers. Serum levels of fasting insulin (FINS) were measured using an automated electrochemiluminescence system. Serum levels of OC and undercarboxylated osteocalcin (ucOC) were measured by enzyme-linked immunosorbent assay. Grip strength and timed-up-and-go (TUG) test were measured. Bone mineral density (BMD) and body composition were measured using dual-energy X-ray absorptiometry. RESULTS OI patients had significantly higher body mass index (BMI), FBG, and HOMA-IR, but lower HDL-C levels, lower grip strength and longer TUG than control group (all P<0.05). Serum OC, ucOC levels, and ucOC/OC in OI type III patients were significantly lower than those in OI patients with type I and IV. Serum levels of OC, ucOC, and ucOC/OC were negatively correlated to BMI, FBG, insulin levels, and HOMA-IR (all P<0.05). The ratio of ucOC/OC was positively correlated to grip strength (r=0.512, P=0.036), lean mass percentage (%LM) of the total body and limbs, and negatively correlated to fat mass percentage (%FM) of the total body, %FM and fat mass index (FMI) of the trunk (all P<0.05). CONCLUSIONS Obesity, glucolipid metabolic abnormalities, and reduced grip strength were common in children with OI. Circulating osteocalcin and ucOC may play an important role in the regulation of glucose metabolism, as well as the muscle function of children with OI.
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Affiliation(s)
- Wen-bin Zheng
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Hu
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Di-Chen Zhao
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Bing-Na Zhou
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ou Wang
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yan Jiang
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wei-Bo Xia
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiao-ping Xing
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Mei Li
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- *Correspondence: Mei Li,
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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: 5] [Impact Index Per Article: 1.7] [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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Salau VF, Erukainure OL, Olofinsan KA, Ijomone OM, Msomi NZ, Islam MS. Vanillin modulates activities linked to dysmetabolism in psoas muscle of diabetic rats. Sci Rep 2021; 11:18724. [PMID: 34548565 PMCID: PMC8455626 DOI: 10.1038/s41598-021-98158-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 09/06/2021] [Indexed: 01/16/2023] Open
Abstract
Skeletal muscles are important in glucose metabolism and are affected in type 2 diabetes (T2D) and its complications. This study investigated the effect of vanillin on redox imbalance, cholinergic and purinergic dysfunction, and glucose-lipid dysmetabolism in muscles of rats with T2D. Male albino rats (Sprague-Dawley strain) were fed 10% fructose ad libitum for 2 weeks before intraperitoneally injecting them with 40 mg/kg streptozotocin to induce T2D. Low (150 mg/kg bodyweight (BW)) and high (300 mg/kg BW) doses of vanillin were orally administered to diabetic rats. Untreated diabetic rats and normal rats made up the diabetic control (DC) and normal control (NC) groups, respectively. The standard antidiabetic drug was metformin. The rats were humanely put to sleep after 5 weeks of treatment and their psoas muscles were harvested. There was suppression in the levels of glutathione, activities of SOD, catalase, ENTPDase, 5'Nucleotidase and glycogen levels on T2D induction. This was accompanied by concomitantly elevated levels of malondialdehyde, serum creatine kinase-MB, nitric oxide, acetylcholinesterase, ATPase, amylase, lipase, glucose-6-phosphatase (G6Pase), fructose-1,6-biphophastase (FBPase) and glycogen phosphorylase activities. T2D induction further resulted in the inactivation of fatty acid biosynthesis, glycerolipid metabolism, fatty acid elongation in mitochondria and fatty acid metabolism pathways. There were close to normal and significant reversals in these activities and levels, with concomitant reactivation of the deactivated pathways following treatment with vanillin, which compared favorably with the standard drug (metformin). Vanillin also significantly increased muscle glucose uptake ex vivo. The results suggest the therapeutic effect of vanillin against muscle dysmetabolism in T2D as portrayed by its ability to mitigate redox imbalance, inflammation, cholinergic and purinergic dysfunctions, while modulating glucose-lipid metabolic switch and maintaining muscle histology.
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Affiliation(s)
- Veronica F Salau
- Department of Biochemistry, University of KwaZulu-Natal, Westville Campus, Durban, 4000, South Africa
- Department of Biochemistry, Veritas University, Bwari, Abuja, Nigeria
| | - Ochuko L Erukainure
- Department of Pharmacology, University of the Free State, Bloemfontein, 9300, South Africa
| | - Kolawole A Olofinsan
- Department of Biochemistry, University of KwaZulu-Natal, Westville Campus, Durban, 4000, South Africa
| | - Omamuyovwi M Ijomone
- Department of Human Anatomy, School of Health and Health Technology, Federal University of Technology, Akure, Nigeria
| | - Nontokozo Z Msomi
- Department of Biochemistry, University of KwaZulu-Natal, Westville Campus, Durban, 4000, South Africa
| | - Md Shahidul Islam
- Department of Biochemistry, University of KwaZulu-Natal, Westville Campus, Durban, 4000, South Africa.
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Erukainure OL, Salau VF, Atolani O, Ravichandran R, Banerjee P, Preissner R, Koorbanally NA, Islam MS. L-leucine stimulation of glucose uptake and utilization involves modulation of glucose - lipid metabolic switch and improved bioenergetic homeostasis in isolated rat psoas muscle ex vivo. Amino Acids 2021; 53:1135-1151. [PMID: 34152488 DOI: 10.1007/s00726-021-03021-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/16/2021] [Indexed: 12/21/2022]
Abstract
The antidiabetic effect of l-leucine has been attributed to its modulatory effect on glucose uptake and lipid metabolism in muscles. However, there is a dearth on its effect on glucose metabolism in muscles. Thus, the present study investigated the effect of l-leucine - stimulated glucose uptake on glucose metabolism, dysregulated lipid metabolic pathways, redox and bioenergetic homeostasis, and proteolysis in isolated psoas muscle from Sprague Dawley male rats. Isolated psoas muscles were incubated with l-leucine (30-240 μg/mL) in the presence of 11.1 mMol glucose at 37 ˚C for 2 h. Muscles incubated in only glucose served as the control, while muscles not incubated in l-leucine and/or glucose served as the normal control. Metformin (6.04 mM) was used as the standard antidiabetic drug. Incubation with l-leucine caused a significant increase in muscle glucose uptake, with an elevation of glutathione levels, superoxide dismutase, catalase, E-NTPDase and 5'nucleotidase activities. It also led to the depletion of malondialdehyde and nitric oxide levels, ATPase, chymotrypsin, acetylcholinesterase, glycogen phosphorylase, glucose-6-phosphatase, fructose-1,6-bisphosphatase and lipase activities. There was an alteration in lipid metabolites, with concomitant activation of glycerolipid metabolism, fatty acid metabolism, and fatty acid elongation in mitochondria in the glucose-incubated muscle (negative control). Incubation with l-leucine reversed these alterations, and concomitantly deactivated the pathways. These results indicate that l-leucine-enhanced muscle glucose uptake involves improved redox and bioenergetic homeostasis, with concomitant suppressed proteolytic, glycogenolytic and gluconeogenetic activities, while modulating glucose - lipid metabolic switch.
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Affiliation(s)
- Ochuko L Erukainure
- Department of Pharmacology, School of Clinical Medicine, Faculty of Health Sciences, University of the Free State, Bloemfontein, 9301, South Africa.
| | - Veronica F Salau
- Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban, 4000, South Africa
| | | | - Rahul Ravichandran
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100, Caserta, Italy
| | - Priyanka Banerjee
- Institute for Physiology, Charité - University Medicine Berlin, Berlin, Germany
| | - Robert Preissner
- Institute for Physiology, Charité - University Medicine Berlin, Berlin, Germany
| | - Neil A Koorbanally
- School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, Durban, 4000, South Africa
| | - Md Shahidul Islam
- School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, Durban, 4000, South Africa
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Endocrine role of bone in the regulation of energy metabolism. Bone Res 2021; 9:25. [PMID: 34016950 PMCID: PMC8137703 DOI: 10.1038/s41413-021-00142-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 12/20/2020] [Accepted: 01/12/2021] [Indexed: 02/06/2023] Open
Abstract
Bone mainly functions as a supportive framework for the whole body and is the major regulator of calcium homeostasis and hematopoietic function. Recently, an increasing number of studies have characterized the significance of bone as an endocrine organ, suggesting that bone-derived factors regulate local bone metabolism and metabolic functions. In addition, these factors can regulate global energy homeostasis by altering insulin sensitivity, feeding behavior, and adipocyte commitment. These findings may provide a new pathological mechanism for related metabolic diseases or be used in the diagnosis, treatment, and prevention of metabolic diseases such as osteoporosis, obesity, and diabetes mellitus. In this review, we summarize the regulatory effect of bone and bone-derived factors on energy metabolism and discuss directions for future research.
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8
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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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9
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Mohammad Rahimi GR, Niyazi A, Alaee S. The effect of exercise training on osteocalcin, adipocytokines, and insulin resistance: a systematic review and meta-analysis of randomized controlled trials. Osteoporos Int 2021; 32:213-224. [PMID: 32803318 DOI: 10.1007/s00198-020-05592-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 08/07/2020] [Indexed: 02/07/2023]
Abstract
Recently, it has been reported that osteocalcin (OC), in particular its undercarboxylated (ucOC) form, is not only a bone remodeling marker but also an active hormone that intercedes glucose metabolism in humans. This study aimed to determine the impact of an exercise intervention on ucOC, adiponectin, leptin, and insulin resistance (measured by HOMA-IR). PubMed, CINAHL, Medline, Google Scholar, and Scopus databases and reference lists of included studies were searched. Twenty-two randomized controlled trials (RCTs) of exercise training impact in adults were included in the analysis. Results showed an overall significant increase in serum ucOC (MD: 0.15 ng/ml; 95% CI: 0.05 to 0.25) and adiponectin (MD: 2.83 mg/ml; 95% CI: 1.67 to 3.98), a significant decline in leptin (MD: - 4.89 pg/ml; 95% CI: - 6.94 to - 2.84), fasting glucose (MD: - 2.29 mg/dl; 95% CI: - 4.04 to - 0.54), fasting insulin (MD, - 8.90 μIU/ml; 95% CI: - 13.81 to - 3.98), and HOMA-IR (MD: - 1.96; 95% CI: - 3.11 to - 0.80). However, after removal of studies that had prescribed a balanced diet along with exercise intervention, total OC (TOC) levels also increased in the exercise group compared with the control group (MD: 0.36 ng/ml; 95% CI: 0.07 to 0.65). Our findings demonstrate that exercise-induced increases in ucOC are the probable cause of increased adiponectin. Additionally, increases in ucOC itself are probably due to changes in leptin levels and other factors, rather than its direct impact on bone and its osteoblastic activity. Further studies are required to clarify the mechanisms underlying the impact of exercise training on ucOC, adipocytokines, and insulin resistance.
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Affiliation(s)
- Gh R Mohammad Rahimi
- Department of Sports Sciences, Vahdat Institute of Higher Education, Torbat-e-Jam, Iran.
| | | | - S Alaee
- Department of Physical Education, Islamic Azad University, Neyshabur Branch, Neyshabur, Iran
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10
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Kirk B, Feehan J, Lombardi G, Duque G. Muscle, Bone, and Fat Crosstalk: the Biological Role of Myokines, Osteokines, and Adipokines. Curr Osteoporos Rep 2020; 18:388-400. [PMID: 32529456 DOI: 10.1007/s11914-020-00599-y] [Citation(s) in RCA: 231] [Impact Index Per Article: 57.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW Skeletal muscle and bone are connected anatomically and physiologically, and play a crucial role in human locomotion and metabolism. Historically, the coupling between muscle and bone has been viewed in light of mechanotransduction, which dictates that the mechanical forces applied to muscle are transmitted to the skeleton to initiate bone formation. However, these organs also communicate through the endocrine system, orchestrated by a family of cytokines namely myokines (derived from myocytes) and osteokines (derived from bone cells). A third player in this biochemical crosstalk is adipose tissue and the secretion of adipokines (derived from adipocytes). In this review, we discuss the bidirectional effects of myokines and osteokines on muscle and bone metabolism, and the impact of adipokines on both of these secretory organs. RECENT FINDINGS Several myokines, notably, IL6, irisin, IGF-1, BDNF, myostatin, and FGF2 exert anabolic/catabolic effects on bone, while the osteokines osteocalcin and sclerostin have shown to induce muscle anabolism and catabolism, respectively. Adipokines, such as leptin, resistin, adiponectin, and TNFα (released from adipose tissue), can also modulate muscle and bone metabolism. Contrarily, exercise-mediated release of lipolytic myokines (IL6, irisin, and LIF) stimulates thermogenesis by promoting the browning of adipocytes. Myokines, osteokines, and adipokines exert autocrine/paracrine effects locally as well as through the endocrine system, to regulate muscle, bone, and fat metabolism. Reductions in physical activity and increases in energy intake, both linked with aging, leads to adipocyte hypertrophy and the recruitment of immunological cells (macrophages). In turn, this releases pro-inflammatory adipokines which induces chronic low-grade inflammation (LGI), a key player in the pathology of several diseases. However, exercise-induced stimulation of bioactive cytokines, through muscle-bone-fat crosstalk, increases muscle anabolism, bone formation, mitochondrial biogenesis, glucose utilization, and fatty acid oxidation, and attenuates chronic LGI.
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Affiliation(s)
- Ben Kirk
- Department of Medicine-Western Health, Melbourne Medical School, University of Melbourne, St Albans, VIC, Australia
- Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia
| | - Jack Feehan
- Department of Medicine-Western Health, Melbourne Medical School, University of Melbourne, St Albans, VIC, Australia
- Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia
| | - Giovanni Lombardi
- Laboratory of Experimental Biochemistry & Molecular Biology, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
- Department of Athletics, Strength and Conditioning, Poznań University of Physical Education, Poznań, Poland
| | - Gustavo Duque
- Department of Medicine-Western Health, Melbourne Medical School, University of Melbourne, St Albans, VIC, Australia.
- Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia.
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11
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Karsenty G. The facts of the matter: What is a hormone? PLoS Genet 2020; 16:e1008938. [PMID: 32589668 PMCID: PMC7319275 DOI: 10.1371/journal.pgen.1008938] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 06/17/2020] [Indexed: 12/17/2022] Open
Affiliation(s)
- Gerard Karsenty
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, New York, United States of America
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12
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Lin X, Onda DA, Yang CH, Lewis JR, Levinger I, Loh K. Roles of bone-derived hormones in type 2 diabetes and cardiovascular pathophysiology. Mol Metab 2020; 40:101040. [PMID: 32544571 PMCID: PMC7348059 DOI: 10.1016/j.molmet.2020.101040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/28/2020] [Accepted: 06/11/2020] [Indexed: 02/07/2023] Open
Abstract
Background Emerging evidence demonstrates that bone is an endocrine organ capable of influencing multiple physiological and pathological processes through the secretion of hormones. Recent research suggests complex crosstalk between the bone and other metabolic and cardiovascular tissues. It was uncovered that three of these bone-derived hormones—osteocalcin, lipocalin 2, and sclerostin—are involved in the endocrine regulations of cardiometabolic health and play vital roles in the pathophysiological process of developing cardiometabolic syndromes such as type 2 diabetes and cardiovascular disease. Chronic low-grade inflammation is one of the hallmarks of cardiometabolic diseases and a major contributor to disease progression. Novel evidence also implicates important roles of bone-derived hormones in the regulation of chronic inflammation. Scope of review In this review, we provide a detailed overview of the physiological and pathological roles of osteocalcin, lipocalin 2, and sclerostin in cardiometabolic health regulation and disease development, with a focus on the modulation of chronic inflammation. Major conclusions Evidence supports that osteocalcin has a protective role in cardiometabolic health, and an increase of lipocalin 2 contributes to the development of cardiometabolic diseases partly via pro-inflammatory effects. The roles of sclerostin appear to be complicated: It exerts pro-adiposity and pro-insulin resistance effects in type 2 diabetes and has an anti-calcification effect during cardiovascular disease. A better understanding of the actions of these bone-derived hormones in the pathophysiology of cardiometabolic diseases will provide crucial insights to help further research develop new therapeutic strategies to treat these diseases.
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Affiliation(s)
- Xuzhu Lin
- St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia.
| | - Danise-Ann Onda
- St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia
| | - Chieh-Hsin Yang
- St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia
| | - Joshua R Lewis
- School of Medical and Health Sciences, Edith Cowan University, Perth, Australia; Medical School, University of Western Australia, Perth, Australia
| | - Itamar Levinger
- Institute for Health and Sport (IHES), Victoria University, Footscray, VIC, Australia; Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, Australia
| | - Kim Loh
- St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia; Department of Medicine, University of Melbourne, Parkville, VIC, Australia.
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13
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Uncarboxylated osteocalcin decreases insulin-stimulated glucose uptake without affecting insulin signaling and regulators of mitochondrial biogenesis in myotubes. J Physiol Biochem 2020; 76:169-178. [DOI: 10.1007/s13105-020-00732-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 02/07/2020] [Indexed: 01/28/2023]
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14
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Ala M, Jafari RM, Dehpour AR. Diabetes Mellitus and Osteoporosis Correlation: Challenges and Hopes. Curr Diabetes Rev 2020; 16:984-1001. [PMID: 32208120 DOI: 10.2174/1573399816666200324152517] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 02/02/2020] [Accepted: 02/24/2020] [Indexed: 01/14/2023]
Abstract
Diabetes and osteoporosis are two common diseases with different complications. Despite different therapeutic strategies, managing these diseases and reducing their burden have not been satisfactory, especially when they appear one after the other. In this review, we aimed to clarify the similarity, common etiology and possible common adjunctive therapies of these two major diseases and designate the known molecular pattern observed in them. Based on different experimental findings, we want to illuminate that interestingly similar pathways lead to diabetes and osteoporosis. Meanwhile, there are a few drugs involved in the treatment of both diseases, which most of the time act in the same line but sometimes with opposing results. Considering the correlation between diabetes and osteoporosis, more efficient management of both diseases, in conditions of concomitant incidence or cause and effect condition, is required.
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Affiliation(s)
- Moein Ala
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, 13145-784, Tehran, Iran
| | - Razieh Mohammad Jafari
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Reza Dehpour
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, 13145-784, Tehran, Iran
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15
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Qaradakhi T, Gadanec LK, Tacey AB, Hare DL, Buxton BF, Apostolopoulos V, Levinger I, Zulli A. The Effect of Recombinant Undercarboxylated Osteocalcin on Endothelial Dysfunction. Calcif Tissue Int 2019; 105:546-556. [PMID: 31485687 DOI: 10.1007/s00223-019-00600-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 08/19/2019] [Indexed: 01/05/2023]
Abstract
Low circulating levels of undercarboxylated osteocalcin (ucOC) is associated with a higher risk of cardiovascular disease, yet whether ucOC has a direct effect on endothelium-dependent vasorelaxation, or in proximity to its postulated receptor, the class CG protein-coupled receptor (GPCR6A), in blood vessels remains unclear. Immunohistochemistry and proximity ligation assays were used to localize the presence of ucOC and GPRC6A and to determine the physical proximity (< 40 nm) in radial artery segments collected from patients undergoing coronary artery bypass surgery (n = 6) which exhibited calcification (determined by Von Kossa) and aorta from New Zealand white rabbits exhibiting atherosclerotic plaques. Endothelium-dependent vasorelaxation was assessed using cumulative doses of acetylcholine in vitro on abdominal aorta of rabbits fed a normal chow diet (n = 10) and a 4-week atherogenic diet (n = 9) pre-incubated with ucOC (10 ng/mL) or vehicle. Both ucOC and GPRC6A were localized in human and rabbit diseased-blood vessels. Proximity ligation assay staining demonstrated physical proximity of ucOC with GPRC6A only within plaques in rabbit arteries and the endothelium layer of rabbit arterioles. Endothelium-dependent vasorelaxation was impaired in atherogenic abdominal aorta compared to healthy aorta and ucOC attenuated this impairment. ucOC attenuated impaired endothelium-dependent vasorelaxation in rabbit abdominal aorta following an atherogenic diet, however, this effect may be independent of GPRC6A. It is important that future studies determine the underlying cellular mechanisms by which ucOC effects blood vessels as well as whether it can be used as a therapeutic agent against the progression of atherosclerosis.
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Affiliation(s)
- Tawar Qaradakhi
- Institute for Health and Sport, Victoria University, Melbourne, VIC, 8001, Australia.
| | - Laura K Gadanec
- Institute for Health and Sport, Victoria University, Melbourne, VIC, 8001, Australia
| | - Alexander B Tacey
- Institute for Health and Sport, Victoria University, Melbourne, VIC, 8001, Australia
- Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, 3021, Australia
| | - David L Hare
- Department of Cardiology, Austin Health, University of Melbourne, Heidelberg, VIC, 3084, Australia
| | - Brian F Buxton
- University of Melbourne, Consultant in Cardiac Surgery, Melbourne, VIC, Australia
| | - Vasso Apostolopoulos
- Institute for Health and Sport, Victoria University, Melbourne, VIC, 8001, Australia
| | - Itamar Levinger
- Institute for Health and Sport, Victoria University, Melbourne, VIC, 8001, Australia
- Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St Albans, VIC, 3021, Australia
| | - Anthony Zulli
- Institute for Health and Sport, Victoria University, Melbourne, VIC, 8001, Australia
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16
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Lin X, Parker L, McLennan E, Hayes A, McConell G, Brennan-Speranza TC, Levinger I. Undercarboxylated Osteocalcin Improves Insulin-Stimulated Glucose Uptake in Muscles of Corticosterone-Treated Mice. J Bone Miner Res 2019; 34:1517-1530. [PMID: 30908701 DOI: 10.1002/jbmr.3731] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/18/2019] [Accepted: 03/20/2019] [Indexed: 01/05/2023]
Abstract
Short-term administration of glucocorticoids (GCs) impairs muscle insulin sensitivity at least in part via the reduction of undercarboxylated osteocalcin (ucOC). However, whether ucOC treatment reverses the GC-induced muscle insulin resistance remains unclear. To test the hypothesis that ucOC directly ameliorates impaired insulin-stimulated glucose uptake (ISGU) induced by short-term GC administration in mice muscle and to identify the molecular mechanisms, mice were implanted with placebo or corticosterone (CS) slow-release pellets. Two days post-surgery, insulin-tolerance tests (ITTs) were performed. On day 3, serum was collected and extensor digitorum longus (EDL) and soleus muscles were isolated and treated ex vivo with vehicle, ucOC (30 ng/mL), insulin (60 µU/mL), or both. Circulating hormone levels, muscle glucose uptake, and muscle signaling proteins were assessed. CS administration reduced both serum osteocalcin and ucOC levels, whole-body insulin sensitivity, and muscle ISGU in EDL. Ex vivo ucOC treatment restored ISGU in CS-affected muscle, without increasing non-insulin-stimulated glucose uptake. In CS-affected EDL muscle, ucOC enhanced insulin action on phosphorylated (p-)protein kinase B (Akt)Ser473 and the p-extracellular signal-regulated kinase isoform 2 (ERK2)Thr202/Tyr204 /total (t)ERK2 ratio, which correlated with ISGU. In CS-affected soleus muscle, ucOC enhanced insulin action on p-mammalian target of rapamycin (mTOR)Ser2481 , the p-mTORSer2481 /tmTOR ratio, p-Akt substrate of 160kD (AS160)Thr642 , and p-protein kinase C (PKC) (pan)Thr410 , which correlated with ISGU. Furthermore, p-PKC (pan)Thr410 correlated with p-AktSer473 and p-AS160Thr642 . ucOC exerts direct insulin-sensitizing effects on CS-affected mouse muscle, likely through an enhancement in activity of key proteins involved in both insulin and ucOC signaling pathways. Furthermore, these effects are muscle type-dependent. © 2019 American Society for Bone and Mineral Research.
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Affiliation(s)
- Xuzhu Lin
- Institute of Health and Sport (IHES), Victoria University, Melbourne, Australia
| | - Lewan Parker
- Institute of Health and Sport (IHES), Victoria University, Melbourne, Australia.,Institute for Physical Activity and Nutrition (IPAN), Deakin University, Geelong, VIC, Australia
| | - Emma McLennan
- Institute of Health and Sport (IHES), Victoria University, Melbourne, Australia
| | - Alan Hayes
- Institute of Health and Sport (IHES), Victoria University, Melbourne, Australia.,College of Health and Biomedicine, Victoria University, Melbourne, VIC, Australia.,Department of Medicine-Western Health, Australian Institute for Musculoskeletal Science (AIMSS), Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia
| | - Glenn McConell
- Institute of Health and Sport (IHES), Victoria University, Melbourne, Australia
| | - Tara C Brennan-Speranza
- Department of Physiology and Bosch Institute for Medical Research, University of Sydney, Australia
| | - Itamar Levinger
- Institute of Health and Sport (IHES), Victoria University, Melbourne, Australia.,Department of Medicine-Western Health, Australian Institute for Musculoskeletal Science (AIMSS), Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia
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17
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Hiam D, Voisin S, Yan X, Landen S, Jacques M, Papadimitriou ID, Munson F, Byrnes E, Brennan-Speranza TC, Levinger I, Eynon N. The association between bone mineral density gene variants and osteocalcin at baseline, and in response to exercise: The Gene SMART study. Bone 2019; 123:23-27. [PMID: 30878522 DOI: 10.1016/j.bone.2019.03.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/27/2019] [Accepted: 03/12/2019] [Indexed: 01/03/2023]
Abstract
INTRODUCTION Osteocalcin (OC) is used as a surrogate marker for bone turnover in clinical settings. As bone mineral density (BMD) is largely heritable, we tested the hypothesis that a) bone-associated genetic variants previously identified in Genome-Wide Association Studies (GWAS) and combined into a genetic risk score (GRS) are associated with a) circulating levels of OC and b) the changes in OC following acute exercise. METHODS Total OC (tOC), undercarboxylated OC (ucOC), and carboxylated OC (cOC) were measured in serum of 73 healthy Caucasian males at baseline and after a single bout of high-intensity interval exercise. In addition, genotyping was conducted targeting GWAS variants previously reported to be associated with BMD and then combined into a GRS. Potential associations between the GRS and tOC, ucOC and cOC were tested with linear regressions adjusted for age. RESULTS At baseline none of the individual SNPs associated with tOC, ucOC and cOC. However, when combined, a higher GRS was associated with higher tOC (β = 0.193 ng/mL; p = 0.037; 95% CI = 0.012, 0.361) and cOC (β = 0.188 ng/mL; p = 0.04; 95% CI = 0.004, 0.433). Following exercise, GRS was associated with ucOC levels, (β = 3.864 ng/mL; p-value = 0.008; 95% CI = 1.063, 6.664) but not with tOC or cOC. CONCLUSION Screening for genetic variations may assist in identifying people at risk for abnormal circulating levels of OC at baseline/rest. Genetic variations in BMD predicted the ucOC response to acute exercise indicating that physiological functional response to exercise may be influenced by bone-related gene variants.
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Affiliation(s)
- Danielle Hiam
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia
| | - Sarah Voisin
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia
| | - Xu Yan
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia
| | - Shanie Landen
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia
| | - Macsue Jacques
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia
| | | | - Fiona Munson
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia
| | | | | | - Itamar Levinger
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia.; Science (AIMSS), Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia
| | - Nir Eynon
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia.; Murdoch Childrens Research Institute, Melbourne, Australia.
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18
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Parker L, Lin X, Garnham A, McConell G, Stepto NK, Hare DL, Byrnes E, Ebeling PR, Seeman E, Brennan-Speranza TC, Levinger I. Glucocorticoid-Induced Insulin Resistance in Men Is Associated With Suppressed Undercarboxylated Osteocalcin. J Bone Miner Res 2019; 34:49-58. [PMID: 30138543 DOI: 10.1002/jbmr.3574] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 08/05/2018] [Accepted: 08/08/2018] [Indexed: 12/15/2022]
Abstract
In mice, glucocorticoid-induced insulin resistance occurs largely through impaired osteoblast function and decreased circulating undercarboxylated osteocalcin (ucOC). Whether these mechanisms contribute to glucocorticoid-induced insulin resistance in humans has yet to be established. In addition, the effects of glucocorticoids on the exercise-induced increase in circulating ucOC and insulin sensitivity are also unknown. We hypothesized that acute glucocorticoid treatment would lead to basal and postexercise insulin resistance in part through decreased circulating ucOC and ucOC-mediated skeletal muscle protein signaling. Nine healthy men completed two separate cycling sessions 12 hours after ingesting either glucocorticoid (20 mg prednisolone) or placebo (20 mg Avicel). The homeostatic model assessment was used to assess basal insulin sensitivity and a 2-hour euglycemic-hyperinsulinemic clamp was commenced 3 hours after exercise to assess postexercise insulin sensitivity. Serum ucOC and skeletal muscle protein signaling were measured. Single-dose glucocorticoid ingestion increased fasting glucose (27%, p < 0.01) and insulin (83%, p < 0.01), and decreased basal insulin sensitivity (-47%, p < 0.01). Glucocorticoids reduced insulin sensitivity after cycling exercise (-34%, p < 0.01), reduced muscle GPRC6A protein content (16%, p < 0.05), and attenuated protein phosphorylation of mTORSer2481 , AktSer374 , and AS160Thr642 (59%, 61%, and 50%, respectively; all ps < 0.05). Serum ucOC decreased (-24%, p < 0.01) which correlated with lower basal insulin sensitivity (r = 0.54, p = 0.02), lower insulin sensitivity after exercise (r = 0.72, p < 0.05), and attenuated muscle protein signaling (r = 0.48-0.71, p < 0.05). Glucocorticoid-induced basal and postexercise insulin resistance in humans is associated with the suppression of circulating ucOC and ucOC-linked protein signaling in skeletal muscle. Whether ucOC treatment can offset glucocorticoid-induced insulin resistance in human subjects requires further investigation. © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
- Lewan Parker
- Institute for Physical Activity and Nutrition (IPAN), Deakin University, Geelong, VIC, Australia.,Institute of Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia
| | - Xuzhu Lin
- Institute of Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia
| | - Andrew Garnham
- Institute for Physical Activity and Nutrition (IPAN), Deakin University, Geelong, VIC, Australia.,Institute of Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia
| | - Glenn McConell
- Institute of Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia
| | - Nigel K Stepto
- Institute of Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia.,Australian Institute for Musculoskeletal Science (AIMSS), Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia.,Monash Centre of Health Research and Implementation (MCHRI), School of Public Health and Preventative Medicine, Monash University, Melbourne, VIC, Australia
| | - David L Hare
- University of Melbourne and the Department of Cardiology, Austin Health, Melbourne, VIC, Australia
| | | | - Peter R Ebeling
- Department of Medicine, School of Clinical Sciences, Monash University, Melbourne, VIC, Australia
| | - Ego Seeman
- Department of Endocrinology, Austin Health, University of Melbourne, Melbourne, VIC, Australia.,Mary Mackillop Institute of Health Research, Australian Catholic University, Melbourne, VIC, Australia
| | | | - Itamar Levinger
- Institute of Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia.,Australian Institute for Musculoskeletal Science (AIMSS), Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia.,University of Melbourne and the Department of Cardiology, Austin Health, Melbourne, VIC, Australia
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19
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Abstract
The skeleton shows an unconventional role in the physiology and pathophysiology of the human organism, not only as the target tissue for a number of systemic hormones, but also as endocrine tissue modulating some skeletal and extraskeletal systems. From this point of view, the principal cells in the skeleton are osteocytes. These cells primarily work as mechano-sensors and modulate bone remodeling. Mechanically unloaded osteocytes synthetize sclerostin, the strong inhibitor of bone formation and RANKL, the strong activator of bone resorption. Osteocytes also express hormonally active vitamin D (1,25(OH)2D) and phosphatonins, such as FGF23. Both 1,25(OH)2D and FGF23 have been identified as powerful regulators of the phosphate metabolism, including in chronic kidney disease. Further endocrine cells of the skeleton involved in bone remodeling are osteoblasts. While FGF23 targets the kidney and parathyroid glands to control metabolism of vitamin D and phosphates, osteoblasts express osteocalcin, which through GPRC6A receptors modulates beta cells of the pancreatic islets, muscle, adipose tissue, brain and testes. This article reviews some knowledge concerning the interaction between the bone hormonal network and phosphate or energy homeostasis and/or male reproduction.
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Affiliation(s)
- I. ZOFKOVA
- Institute of Endocrinology, Prague, Czech Republic
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20
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Kanazawa I, Takeno A, Tanaka KI, Notsu M, Sugimoto T. Osteoblast AMP-activated protein kinase regulates glucose metabolism and bone mass in adult mice. Biochem Biophys Res Commun 2018; 503:1955-1961. [DOI: 10.1016/j.bbrc.2018.07.141] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 07/27/2018] [Indexed: 01/07/2023]
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21
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Lin X, Parker L, Mclennan E, Zhang X, Hayes A, McConell G, Brennan-Speranza TC, Levinger I. Uncarboxylated Osteocalcin Enhances Glucose Uptake Ex Vivo in Insulin-Stimulated Mouse Oxidative But Not Glycolytic Muscle. Calcif Tissue Int 2018; 103:198-205. [PMID: 29427234 DOI: 10.1007/s00223-018-0400-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 01/31/2018] [Indexed: 01/14/2023]
Abstract
Uncarboxylated osteocalcin (ucOC) stimulates muscle glucose uptake in mice EDL and soleus muscles. However, whether ucOC also exerts a similar effect in insulin-stimulated muscles in a muscle type-specific manner is currently unclear. We aimed to test the hypothesis that, with insulin stimulation, ucOC per se has a greater effect on oxidative muscle compared with glycolytic muscle, and to explore the underlying mechanisms. Mouse (C57BL6, male 9-12 weeks) extensor digitorum longus (EDL) and soleus muscles were isolated and longitudinally split into halves. Muscle samples were treated with varying doses of recombinant ucOC (0, 0.3, 1, 3, 30 ng/ml), followed by insulin addition. Muscle glucose uptake, protein phosphorylation and total expression of protein kinase B (Akt), Akt substrate of 160 kDa (AS160), extracellular signal-regulated kinase isoform 2 (ERK2), and adenosine monophosphate-activated protein kinase subunit α (AMPKα) were assessed. ucOC treatment at 30 ng/ml enhanced muscle glucose uptake in insulin-stimulated soleus, a mainly oxidative muscle (17.5%, p < 0.05), but not in EDL-a mostly glycolytic muscle. In insulin-stimulated soleus only, ucOC treatment (3 and 30 ng/ml) increased phosphorylation of AS160 and ERK2, but not Akt or AMPKα. The ucOC-induced increase in ERK2 phosphorylation in soleus was not associated with the increase in glucose uptake or AS160 phosphorylation. ucOC enhances glucose uptake and AS160 phosphorylation in insulin-stimulated oxidative but not glycolytic muscle, via upstream mechanisms which appear to be independent of ERK or AMPK.
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Affiliation(s)
- Xuzhu Lin
- Institute of Health and Sport (IHES), Victoria University, Melbourne, Australia
| | - Lewan Parker
- Institute of Health and Sport (IHES), Victoria University, Melbourne, Australia
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Australia
| | - Emma Mclennan
- Institute of Health and Sport (IHES), Victoria University, Melbourne, Australia
| | - Xinmei Zhang
- Institute of Health and Sport (IHES), Victoria University, Melbourne, Australia
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Australia
| | - Alan Hayes
- Institute of Health and Sport (IHES), Victoria University, Melbourne, Australia
- College of Health and Biomedicine, Victoria University, Melbourne, Australia
- Australian Institute for Musculoskeletal Science, Victoria University, Melbourne, Australia
| | - Glenn McConell
- Institute of Health and Sport (IHES), Victoria University, Melbourne, Australia
| | - Tara C Brennan-Speranza
- Department of Physiology and Bosch Institute for Medical Research, University of Sydney, Sydney, Australia
| | - Itamar Levinger
- Institute of Health and Sport (IHES), Victoria University, Melbourne, Australia.
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Australia.
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22
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Undercarboxylated Osteocalcin: Experimental and Human Evidence for a Role in Glucose Homeostasis and Muscle Regulation of Insulin Sensitivity. Nutrients 2018; 10:nu10070847. [PMID: 29966260 PMCID: PMC6073619 DOI: 10.3390/nu10070847] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 06/22/2018] [Accepted: 06/25/2018] [Indexed: 12/13/2022] Open
Abstract
Recent advances have indicated that osteocalcin, and in particular its undercarboxylated form (ucOC), is not only a nutritional biomarker reflective of vitamin K status and an indicator of bone health but also an active hormone that mediates glucose metabolism in experimental studies. This work has been supported by the putative identification of G protein-coupled receptor, class C, group 6, member A (GPRC6A) as a cell surface receptor for ucOC. Of note, ucOC has been associated with diabetes and with cardiovascular risk in epidemiological studies, consistent with a pathophysiological role for ucOC in vivo. Limitations of existing knowledge include uncertainty regarding the underlying mechanisms by which ucOC interacts with GPRC6A to modulate metabolic and cardiovascular outcomes, technical issues with commonly used assays for ucOC in serum, and a paucity of clinical trials to prove causation and illuminate the scope for novel health interventions. A key emerging area of research is the role of ucOC in relation to expression of GPRC6A in muscle, and whether exercise interventions may modulate metabolic outcomes favorably in part via ucOC. Further research is warranted to clarify potential direct and indirect roles for ucOC in human health and cardiometabolic diseases.
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Zhang X, Hiam D, Hong YH, Zulli A, Hayes A, Rattigan S, McConell GK. Nitric oxide is required for the insulin sensitizing effects of contraction in mouse skeletal muscle. J Physiol 2017; 595:7427-7439. [PMID: 29071734 DOI: 10.1113/jp275133] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 10/18/2017] [Indexed: 01/15/2023] Open
Abstract
KEY POINTS People with insulin resistance or type 2 diabetes can substantially increase their skeletal muscle glucose uptake during exercise and insulin sensitivity after exercise. Skeletal muscle nitric oxide (NO) is important for glucose uptake during exercise, although how prior exercise increases insulin sensitivity is unclear. In the present study, we examined whether NO is necessary for normal increases in skeletal muscle insulin sensitivity after contraction ex vivo in mouse muscle. The present study uncovers, for the first time, a novel role for NO in the insulin sensitizing effects of ex vivo contraction, which is independent of blood flow. ABSTRACT The factors regulating the increase in skeletal muscle insulin sensitivity after exercise are unclear. We examined whether nitric oxide (NO) is required for the increase in insulin sensitivity after ex vivo contractions. Isolated C57BL/6J mouse EDL muscles were contracted for 10 min or remained at rest (basal) with or without the NO synthase (NOS) inhibition (NG -monomethyl-l-arginine; l-NMMA; 100 μm). Then, 3.5 h post contraction/basal, muscles were exposed to saline or insulin (120 μU ml-1 ) with or without l-NMMA during the last 30 min. l-NMMA had no effect on basal skeletal muscle glucose uptake. The increase in muscle glucose uptake with insulin (57%) was significantly (P < 0.05) greater after prior contraction (140% increase). NOS inhibition during the contractions had no effect on this insulin-sensitizing effect of contraction, whereas NOS inhibition during insulin prevented the increase in skeletal muscle insulin sensitivity post-contraction. Soluble guanylate cyclase inhibition, protein kinase G (PKG) inhibition or cyclic nucleotide phosphodiesterase inhibition each had no effect on the insulin-sensitizing effect of prior contraction. In conclusion, NO is required for increases in insulin sensitivity several hours after contraction of mouse skeletal muscle via a cGMP/PKG independent pathway.
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Affiliation(s)
- Xinmei Zhang
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, VIC, Australia.,School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - Danielle Hiam
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, VIC, Australia
| | - Yet-Hoi Hong
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, VIC, Australia
| | - Anthony Zulli
- College of Health and Biomedicine, Victoria University, Melbourne, VIC, Australia
| | - Alan Hayes
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, VIC, Australia.,College of Health and Biomedicine, Victoria University, Melbourne, VIC, Australia
| | - Stephen Rattigan
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Glenn K McConell
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, VIC, Australia.,College of Health and Biomedicine, Victoria University, Melbourne, VIC, Australia
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Brun J, Berthou F, Trajkovski M, Maechler P, Foti M, Bonnet N. Bone Regulates Browning and Energy Metabolism Through Mature Osteoblast/Osteocyte PPARγ Expression. Diabetes 2017; 66:2541-2554. [PMID: 28687706 DOI: 10.2337/db17-0116] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 06/29/2017] [Indexed: 11/13/2022]
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is a master regulator of energy metabolism. In bone, it is known to regulate osteoblast differentiation and osteoclast activity. Whether PPARγ expression in bone cells, particularly osteocytes, regulates energy metabolism remains unknown. Here, we show that mature osteoblast/osteocyte-specific ablation of PPARγ in mice (Ocy-PPARγ-/-) alters body composition with age, namely, to produce less fat and more lean mass, and enhances insulin sensitivity and energy expenditure compared with wild-type mice. In addition, Ocy-PPARγ-/- mice exhibit more bone density, structure, and strength by uncoupling bone formation from resorption. When challenged with a high-fat diet, Ocy-PPARγ-/- mice retain glycemic control, with increased browning of the adipose tissue, decreased gluconeogenesis, and less hepatic steatosis. Moreover, these metabolic effects, particularly an increase in fatty acid oxidation, cannot be explained by decarboxylated osteocalcin changes, suggesting existence of other osteokines that are under the control of PPARγ. We further identify bone morphogenetic protein 7 as one of them. Hence, osteocytes coregulate bone and glucose homeostasis through a PPARγ regulatory pathway, and its inhibition could be clinically relevant for the prevention of glucose metabolic disorders.
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Affiliation(s)
- Julia Brun
- Division of Bone Diseases, Department of Internal Medicine Specialties, Faculty of Medicine, Geneva University Hospital, Geneva, Switzerland
| | - Flavien Berthou
- Department of Cell Physiology and Metabolism, University of Geneva, and Faculty of Medicine, Centre Médical Universitaire, Geneva, Switzerland
| | - Mirko Trajkovski
- Department of Cell Physiology and Metabolism, University of Geneva, and Faculty of Medicine, Centre Médical Universitaire, Geneva, Switzerland
| | - Pierre Maechler
- Department of Cell Physiology and Metabolism, University of Geneva, and Faculty of Medicine, Centre Médical Universitaire, Geneva, Switzerland
| | - Michanlegelo Foti
- Department of Cell Physiology and Metabolism, University of Geneva, and Faculty of Medicine, Centre Médical Universitaire, Geneva, Switzerland
| | - Nicolas Bonnet
- Division of Bone Diseases, Department of Internal Medicine Specialties, Faculty of Medicine, Geneva University Hospital, Geneva, Switzerland
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Park YE, Musson DS, Naot D, Cornish J. Cell–cell communication in bone development and whole-body homeostasis and pharmacological avenues for bone disorders. Curr Opin Pharmacol 2017; 34:21-35. [DOI: 10.1016/j.coph.2017.04.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/07/2017] [Accepted: 04/06/2017] [Indexed: 12/11/2022]
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Levinger I, Yan X, Bishop D, Houweling PJ, Papadimitriou I, Munson F, Byrnes E, Vicari D, Brennan-Speranza TC, Eynon N. The influence of α-actinin-3 deficiency on bone remodelling markers in young men. Bone 2017; 98:26-30. [PMID: 28254467 DOI: 10.1016/j.bone.2017.02.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/27/2017] [Accepted: 02/21/2017] [Indexed: 11/28/2022]
Abstract
There is a large individual variation in the bone remodelling markers (BRMs) osteocalcin (OC), procollagen 1 N-terminal propeptide (P1NP) and β-isomerized C-terminal telopeptide (β-CTx), as well as undercarboxylated osteocalcin (ucOC), at rest and in response to exercise. α-actinin-3 (ACTN3), a sarcomeric protein, is expressed in skeletal muscle and osteoblasts and may influence BRM levels and the cross-talk between muscle and bone. We tested the levels of serum BRMs in α-actinin-3 deficient humans (ACTN3 XX) at baseline, and following a single bout of exercise. Forty-three healthy Caucasian individuals were divided into three groups (ACTN3 XX, n=13; ACTN3 RX, n=16; ACTN3 RR, n=14). Participants completed a single session of High Intensity Interval Exercise (HIIE) on a cycle ergometer (8×2-min intervals at 85% of maximal power). Blood samples were taken before, immediately after, and three hours post exercise to identify the peak changes in serum BRMs. There was a stepwise increase in resting serum BRMs across the ACTN3 genotypes (XX>RX>RR) with significantly higher levels of tOC ~26%, P1NP ~34%, and β-CTX (~33%) in those with ACTN3 XX compared to ACTN3 RR. Following exercise BRMs and ucOC were higher in all three ACTN3 genotypes, with no significant differences between groups. Serum levels of tOC, P1NP and β-CTX are higher in men with ACTN3 XX genotype (α-actinin-3 deficiency) compared to RR and RX. It appears that the response of BRMs and ucOC to exercise is not explained by the ACTN3 genotype.
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Affiliation(s)
- Itamar Levinger
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, Australia.
| | - Xu Yan
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, Australia; Murdoch Childrens Research Institute, Melbourne, Australia
| | - David Bishop
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, Australia; School of Medical and Health Sciences, Edith Cowan University, Perth, Australia
| | | | - Ioannis Papadimitriou
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, Australia
| | - Fiona Munson
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, Australia
| | | | - Daniele Vicari
- Department of Physiology, Bosch Institute for Medical Research, University of Sydney, Sydney, Australia
| | - Tara C Brennan-Speranza
- Department of Physiology, Bosch Institute for Medical Research, University of Sydney, Sydney, Australia
| | - Nir Eynon
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, Australia; Murdoch Childrens Research Institute, Melbourne, Australia.
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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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Lin X, Parker L, Mclennan E, Zhang X, Hayes A, McConell G, Brennan-Speranza TC, Levinger I. Recombinant Uncarboxylated Osteocalcin Per Se Enhances Mouse Skeletal Muscle Glucose Uptake in both Extensor Digitorum Longus and Soleus Muscles. Front Endocrinol (Lausanne) 2017; 8:330. [PMID: 29204135 PMCID: PMC5698688 DOI: 10.3389/fendo.2017.00330] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 11/06/2017] [Indexed: 11/20/2022] Open
Abstract
Emerging evidence suggests that undercarboxylated osteocalcin (ucOC) improves muscle glucose uptake in rodents. However, whether ucOC can directly increase glucose uptake in both glycolytic and oxidative muscles and the possible mechanisms of action still need further exploration. We tested the hypothesis that ucOC per se stimulates muscle glucose uptake via extracellular signal-regulated kinase (ERK), adenosine monophosphate-activated protein kinase (AMPK), and/or the mechanistic target of rapamycin complex 2 (mTORC2)-protein kinase B (AKT)-AKT substrate of 160 kDa (AS160) signaling cascade. Extensor digitorum longus (EDL) and soleus muscles from male C57BL/6 mice were isolated, divided into halves, and then incubated with ucOC with or without the pretreatment of ERK inhibitor U0126. ucOC increased muscle glucose uptake in both EDL and soleus. It also enhanced phosphorylation of ERK2 (Thr202/Tyr204) and AS160 (Thr642) in both muscle types and increased mTOR phosphorylation (Ser2481) in EDL only. ucOC had no significant effect on the phosphorylation of AMPKα (Thr172). The inhibition of ucOC-induced ERK phosphorylation had limited effect on ucOC-stimulated glucose uptake and AS160 phosphorylation in both muscle types, but appeared to inhibit the elevation in AKT phosphorylation only in EDL. Taken together, ucOC at the physiological range directly increased glucose uptake in both EDL and soleus muscles in mouse. The molecular mechanisms behind this ucOC effect on muscle glucose uptake seem to be muscle type-specific, involving enhanced phosphorylation of AS160 but limitedly modulated by ERK phosphorylation. Our study suggests that, since ucOC increases muscle glucose uptake without insulin, it could be considered as a potential agent to improve muscle glucose uptake in insulin resistant conditions.
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Affiliation(s)
- Xuzhu Lin
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia
| | - Lewan Parker
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia
- School of Exercise and Nutrition Sciences, Institute for Physical Activity and Nutrition (IPAN), Deakin University, Melbourne, VIC, Australia
| | - Emma Mclennan
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia
| | - Xinmei Zhang
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia
| | - Alan Hayes
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia
- College of Health and Biomedicine, Victoria University, Geelong, VIC, Australia
- Australian Institute for Musculoskeletal Science, Western Health, Melbourne, VIC, Australia
| | - Glenn McConell
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia
| | - Tara C. Brennan-Speranza
- Department of Physiology, Bosch Institute for Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Itamar Levinger
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia
- Australian Institute for Musculoskeletal Science, Western Health, Melbourne, VIC, Australia
- *Correspondence: Itamar Levinger,
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Pi M, Nishimoto SK, Quarles LD. GPRC6A: Jack of all metabolism (or master of none). Mol Metab 2016; 6:185-193. [PMID: 28180060 PMCID: PMC5279936 DOI: 10.1016/j.molmet.2016.12.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 12/05/2016] [Accepted: 12/15/2016] [Indexed: 01/06/2023] Open
Abstract
Background GPRC6A, a widely expressed G-protein coupled receptor, is proposed to be a master regulator of complex endocrine networks and metabolic processes. GPRC6A is activated by multiple ligands, including osteocalcin (Ocn), testosterone (T), basic amino acids, and various cations. Scope of Review We review the controversy surrounding GPRC6A functions. In mice, GPRC6A is proposed to integrate metabolic functions through the coordinated secretion of hormones, including insulin, GLP-1, T, and IL-6, and direct effects of this receptor to control glucose and fat metabolism in the liver, skeletal muscle, and fat. Loss-of-GPRC6A results in metabolic syndrome (MetS), and activation of GPRC6A stimulates proliferation of β-cells, increases peripheral insulin sensitivity, and protects against high fat diet (HFD) induced metabolic abnormalities in most mouse models. Bone, cardiovascular, immune, and skin functions of GPRC6A have also been identified in mice. Expression of GPRC6A is increased in prostate cancer (PCa) cells, and inhibition of GPRC6A attenuates PCa progression in mouse models. The function of GPRC6A in humans, however, is not clear. During evolution, a unique polymorphism of GPRC6A emerged mainly in humans of Asian and European decent that has been proposed to alter membrane trafficking and function. In contrast, the ancestral allele found in all other species is retained in 1%, 15%, and 40% of people of Asian, European and African descent, respectively, suggesting GPRC6A gene variants may contribute to the racial disparities in the risk of developing MetS and PCa. Major Conclusions If the regulatory functions of GPRC6A identified in mice translate to humans, and polymorphisms in GPRC6A are found to predict racial disparities in human diseases, GPRC6A may be a new gene target to predict, prevent, and treat MetS, PCa, and other disorders impacted by GPRC6A.
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Affiliation(s)
- Min Pi
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Satoru Kenneth Nishimoto
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - L Darryl Quarles
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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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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Levinger I, Brennan-Speranza TC, Stepto NK, Jerums G, Parker L, McConell GK, Anderson M, Garnham A, Hare DL, Ebeling PR, Seeman E. A Single Dose of Prednisolone as a Modulator of Undercarboxylated Osteocalcin and Insulin Sensitivity Post-Exercise in Healthy Young Men: A Study Protocol. JMIR Res Protoc 2016; 5:e78. [PMID: 27259402 PMCID: PMC4912677 DOI: 10.2196/resprot.5119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 01/24/2016] [Accepted: 01/25/2016] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Undercarboxylated osteocalcin (ucOC) increases insulin sensitivity in mice. In humans, data are supportive, but the studies are mostly cross-sectional. Exercise increases whole-body insulin sensitivity, in part via ucOC, while acute glucocorticoid treatment suppresses ucOC in humans and mice. OBJECTIVES A single dose of prednisolone reduces the rise in ucOC produced by exercise, which partly accounts for the failed increase in insulin sensitivity following exercise. METHODS Healthy young men (n=12) aged 18 to 40 years will be recruited. Initial assessments will include analysis of fasting blood, body composition, aerobic power (VO2peak), and peak heart rate. Participants will then be randomly allocated, double-blind, to a single dose of 20 mg of prednisolone or placebo. The two experimental trials will involve 30 minutes of interval exercise (90%-95% peak heart rate), followed by 3 hours of recovery and 2 hours of euglycaemic- hyperinsulinaemic clamp (insulin clamp). Seven muscle biopsies and blood samples will be obtained at rest, following exercise and post-insulin clamps. RESULTS The study is funded by the National Heart Foundation of Australia and Victoria University. Enrollment has already commenced and data collection will be completed in 2016. CONCLUSION If the hypothesis is confirmed, the study will provide novel insights into the potential role of ucOC in insulin sensitivity in human subjects and will elucidate pathways involved in exercise-induced insulin sensitivity.
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Affiliation(s)
- Itamar Levinger
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Australia.
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Qi Z, Liu W, Lu J. The mechanisms underlying the beneficial effects of exercise on bone remodeling: Roles of bone-derived cytokines and microRNAs. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 122:131-139. [PMID: 27179638 DOI: 10.1016/j.pbiomolbio.2016.05.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 05/02/2016] [Accepted: 05/07/2016] [Indexed: 12/31/2022]
Abstract
Bone remodeling is highly dynamic and complex in response to mechanical loading, such as exercise. In this review, we concluded that a number of individual factors are disturbing the clinical effects of exercise on bone remodeling. We updated the progress made on the differentiation of osteoblasts and osteoclasts in response to mechanical loading, hoping to provide a theoretical basis to improve bone metabolism with exercise. Increasing evidences indicate that bone is not only a structural scaffold but also an endocrine organ, which secretes osteocalcin and FGF23. Both of them have been known as a circulating hormone to promote insulin sensitivity and reduce body fat mass. The effects of exercise on these bone-derived cytokines provide a better understanding of how exercise-induced "osteokine" affects the whole-body homeostasis. Additionally, we discussed recent studies highlighting the post-transcriptional regulation of microRNAs in bone remodeling. We focus on the involvement of the microRNAs in osteoblastogenesis and osteoclastogenesis, and suggest that microRNAs may be critical for exercise-induced bone remodeling.
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Affiliation(s)
- Zhengtang Qi
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (East China Normal University), Ministry of Education, Shanghai 200241, China; School of Physical Education and Health, East China Normal University, Shanghai 200241, China
| | - Weina Liu
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (East China Normal University), Ministry of Education, Shanghai 200241, China; School of Physical Education and Health, East China Normal University, Shanghai 200241, China.
| | - Jianqiang Lu
- School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China.
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