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Baroi S, Czernik PJ, Khan MP, Letson J, Crowe E, Chougule A, Griffin PR, Rosen CJ, Lecka-Czernik B. PPARG in osteocytes controls cell bioenergetics and systemic energy metabolism independently of sclerostin levels in circulation. Mol Metab 2024; 88:102000. [PMID: 39074536 DOI: 10.1016/j.molmet.2024.102000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 07/25/2024] [Accepted: 07/26/2024] [Indexed: 07/31/2024] Open
Abstract
OBJECTIVE The skeleton is one of the largest organs in the body, wherein metabolism is integrated with systemic energy metabolism. However, the bioenergetic programming of osteocytes, the most abundant bone cells coordinating bone metabolism, is not well defined. Here, using a mouse model with partial penetration of an osteocyte-specific PPARG deletion, we demonstrate that PPARG controls osteocyte bioenergetics and their contribution to systemic energy metabolism independently of circulating sclerostin levels, which were previously correlated with metabolic status of extramedullary fat depots. METHODS In vivo and in vitro models of osteocyte-specific PPARG deletion, i.e. Dmp1CrePparγflfl male and female mice (γOTKO) and MLO-Y4 osteocyte-like cells with either siRNA-silenced or CRISPR/Cas9-edited Pparγ. As applicable, the models were analyzed for levels of energy metabolism, glucose metabolism, and metabolic profile of extramedullary adipose tissue, as well as the osteocyte transcriptome, mitochondrial function, bioenergetics, insulin signaling, and oxidative stress. RESULTS Circulating sclerostin levels of γOTKO male and female mice were not different from control mice. Male γOTKO mice exhibited a high energy phenotype characterized by increased respiration, heat production, locomotion and food intake. This high energy phenotype in males did not correlate with "beiging" of peripheral adipose depots. However, both sexes showed a trend for reduced fat mass and apparent insulin resistance without changes in glucose tolerance, which correlated with decreased osteocytic responsiveness to insulin measured by AKT activation. The transcriptome of osteocytes isolated from γOTKO males suggested profound changes in cellular metabolism, fuel transport, mitochondria dysfunction, insulin signaling and increased oxidative stress. In MLO-Y4 osteocytes, PPARG deficiency correlated with highly active mitochondria, increased ATP production, and accumulation of reactive oxygen species (ROS). CONCLUSIONS PPARG in male osteocytes acts as a molecular break on mitochondrial function, and protection against oxidative stress and ROS accumulation. It also regulates osteocyte insulin signaling and fuel usage to produce energy. These data provide insight into the connection between osteocyte bioenergetics and their sex-specific contribution to the balance of systemic energy metabolism. These findings support the concept that the skeleton controls systemic energy expenditure via osteocyte metabolism.
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Affiliation(s)
- Sudipta Baroi
- Department of Orthopaedic Surgery, University of Toledo, College of Medicine and Life Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA; Center for Diabetes and Endocrine Research, University of Toledo, College of Medicine and Life Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA.
| | - Piotr J Czernik
- Department of Orthopaedic Surgery, University of Toledo, College of Medicine and Life Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA; Center for Diabetes and Endocrine Research, University of Toledo, College of Medicine and Life Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA.
| | - Mohd Parvez Khan
- Department of Orthopaedic Surgery, University of Toledo, College of Medicine and Life Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA; Center for Diabetes and Endocrine Research, University of Toledo, College of Medicine and Life Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA.
| | - Joshua Letson
- Department of Orthopaedic Surgery, University of Toledo, College of Medicine and Life Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA; Center for Diabetes and Endocrine Research, University of Toledo, College of Medicine and Life Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA.
| | - Emily Crowe
- Department of Orthopaedic Surgery, University of Toledo, College of Medicine and Life Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA; Center for Diabetes and Endocrine Research, University of Toledo, College of Medicine and Life Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA.
| | - Amit Chougule
- Department of Orthopaedic Surgery, University of Toledo, College of Medicine and Life Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA; Center for Diabetes and Endocrine Research, University of Toledo, College of Medicine and Life Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA.
| | - Patrick R Griffin
- The Wertheim UF Scripps Institute, University of Florida, Jupiter, FL 33458, USA.
| | | | - Beata Lecka-Czernik
- Department of Orthopaedic Surgery, University of Toledo, College of Medicine and Life Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA; Center for Diabetes and Endocrine Research, University of Toledo, College of Medicine and Life Sciences, 3000 Arlington Avenue, Toledo, OH 43614, USA.
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Qian J, Li Q, Song Y, Gong X, Hu K, Ge G, Sun Y. Pectolinarigenin ameliorates osteoporosis via enhancing Wnt signaling cascade in PPARβ-dependent manner. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 129:155587. [PMID: 38608598 DOI: 10.1016/j.phymed.2024.155587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 10/03/2023] [Accepted: 04/02/2024] [Indexed: 04/14/2024]
Abstract
BACKGROUND Osteoporosis is a prevalent metabolic bone disease in older adults. Peroxisome proliferator-activated receptor β (PPARβ), the most abundant PPAR isotype expressed in bone tissues, plays a critical role in regulating the energy metabolism of osteoblasts. However, the botanical compounds targeting PPARβ for the treatment of osteoporosis remain largely unexplored. PURPOSE To discover a potent PPARβ agonist from botanical compounds, as well as to investigate the anti-osteoporosis effects and to elucidate the underlying mechanisms of the newly identified PPARβ agonist. METHODS The PPARβ agonist effects of botanical compounds were screened by an in vitro luciferase reporter gene assay. The PPARβ agonist effects of pectolinarigenin (PEC) in bone marrow mesenchymal stromal cells (BMSCs) were validated by Western blotting. RNA-seq transcriptome analyses were conducted to reveal the underlying osteoporosis mechanisms of PEC in BMSCs. The PPARβ antagonist (GSK0660) and Wnt signaling inhibitor (XAV969) were used to explore the role of the PPARβ and Wnt signaling cascade in the anti-osteoporosis effects of PEC. PEC or the PEG-PLGA nanoparticles of PEC (PEC-NP) were intraperitoneally administrated in both wild-type mice and ovariectomy-induced osteoporosis mice to examine its anti-osteoporotic effects in vivo. RESULTS PEC, a newly identified naturally occurring PPARβ agonist, significantly promotes osteogenic differentiation and up-regulates the osteogenic differentiation-related genes (Runx2, Osterix, and Bmp2) in BMSCs. RNA sequencing and functional gene enrichment analysis suggested that PEC could activate osteogenic-related signaling pathways, including Wnt and PPAR signaling pathways. Further investigations suggested that PEC could enhance Wnt/β-catenin signaling in a PPARβ-dependent manner in BMSCs. Animal tests showed that PEC-NP promoted bone mass and density, increased the bone cell matrix protein, and accelerated bone formation in wild-type mice, while PEC-NP also played a preventive role in ovariectomy-induced osteoporosis mice via maintaining the expression level of bone cell matrix protein, balancing the rate of bone formation, and slowing down bone loss. Additionally, PEC-NP did not cause any organ injury and body weight loss after long-term use (11 weeks). CONCLUSION PEC significantly promotes bone formation and reduces bone loss in both BMSCs and ovariectomy-induced osteoporosis mice via enhancing the Wnt signaling cascade in a PPARβ-dependent manner, providing a new alternative therapy for preventing estrogen deficiency-induced osteoporotic diseases.
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Affiliation(s)
- Jun Qian
- Engineering Research Center of Tooth Restoration and Regeneration & Tongji Research Institute of Stomatology & Department of Oral Implantology, Stomatological Hospital and Dental School, Tongji University, Shanghai, China
| | - Qian Li
- Shanghai Frontiers Science Center of TCM Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, PR China; School of Public Health, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, PR China
| | - Yangjie Song
- Shanghai Frontiers Science Center of TCM Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, PR China
| | - Xuyan Gong
- Engineering Research Center of Tooth Restoration and Regeneration & Tongji Research Institute of Stomatology & Department of Oral Implantology, Stomatological Hospital and Dental School, Tongji University, Shanghai, China
| | - Kaili Hu
- Shanghai Frontiers Science Center of TCM Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, PR China.
| | - Guangbo Ge
- Shanghai Frontiers Science Center of TCM Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, PR China.
| | - Yao Sun
- Engineering Research Center of Tooth Restoration and Regeneration & Tongji Research Institute of Stomatology & Department of Oral Implantology, Stomatological Hospital and Dental School, Tongji University, Shanghai, China.
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Lecka-Czernik B, Khan MP, Letson J, Baroi S, Chougule A. Regulatory Effect of Osteocytes on Extramedullary and Bone Marrow Adipose Tissue Development and Function. Curr Osteoporos Rep 2024; 22:301-307. [PMID: 38625510 PMCID: PMC11186862 DOI: 10.1007/s11914-024-00871-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/05/2024] [Indexed: 04/17/2024]
Abstract
PURPOSE OF REVIEW This review summarizes evidence on osteocyte support of extramedullary and bone marrow adipocyte development and discusses the role of endogenous osteocyte activities of nuclear receptors peroxisome proliferator-activated receptor gamma (PPARG) and alpha (PPARA) in this support. RECENT FINDINGS PPARG and PPARA proteins, key regulators of glucose and fatty acid metabolism, are highly expressed in osteocytes. They play significant roles in the regulation of osteocyte secretome and osteocyte bioenergetics; both activities contributing to the levels of systemic energy metabolism in part through an effect on metabolic function of extramedullary and bone marrow adipocytes. The PPARs-controlled osteocyte endocrine/paracrine activities, including sclerostin expression, directly regulate adipocyte function, while the PPARs-controlled osteocyte fuel utilization and oxidative phosphorylation contribute to the skeletal demands for glucose and fatty acids, whose availability is under the control of adipocytes. Bone is an inherent element of systemic energy metabolism with PPAR nuclear receptors regulating osteocyte-adipocyte metabolic axes.
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Affiliation(s)
- Beata Lecka-Czernik
- Department of Orthopaedic Surgery, Center for Diabetes and Endocrine Research, University of Toledo, Toledo, OH, 43614, USA.
| | - Mohd Parvez Khan
- Department of Orthopaedic Surgery, Center for Diabetes and Endocrine Research, University of Toledo, Toledo, OH, 43614, USA
| | - Joshua Letson
- Department of Orthopaedic Surgery, Center for Diabetes and Endocrine Research, University of Toledo, Toledo, OH, 43614, USA
| | - Sudipta Baroi
- Department of Orthopaedic Surgery, Center for Diabetes and Endocrine Research, University of Toledo, Toledo, OH, 43614, USA
- Harvard University, School of Dental Medicine, Boston, MA, 02115, USA
| | - Amit Chougule
- Department of Orthopaedic Surgery, Center for Diabetes and Endocrine Research, University of Toledo, Toledo, OH, 43614, USA
- University of Michigan, Ann Arbor, MI, 48109, USA
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Zhou M, An YZ, Guo Q, Zhou HY, Luo XH. Energy homeostasis in the bone. Trends Endocrinol Metab 2024; 35:439-451. [PMID: 38242815 DOI: 10.1016/j.tem.2023.12.009] [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: 11/01/2023] [Revised: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 01/21/2024]
Abstract
The bone serves as an energy reservoir and actively engages in whole-body energy metabolism. Numerous studies have determined fuel requirements and bioenergetic properties of bone under physiological conditions as well as the dysregulation of energy metabolism associated with bone metabolic diseases. Here, we review the main sources of energy in bone cells and their regulation, as well as the endocrine role of the bone in systemic energy homeostasis. Moreover, we discuss metabolic changes that occur as a result of osteoporosis. Exploration in this area will contribute to an enhanced comprehension of bone energy metabolism, presenting novel possibilities to address metabolic diseases.
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Affiliation(s)
- Min Zhou
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, Hunan 410008, PR China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan 410008, PR China; Key Laboratory of Aging-Related Bone and Joint Diseases Prevention and Treatment, Ministry of Education, Xiangya Hospital, Central South University, Changsha, PR China; Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Hunan 410008, PR China
| | - Yu-Ze An
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, Hunan 410008, PR China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan 410008, PR China; Key Laboratory of Aging-Related Bone and Joint Diseases Prevention and Treatment, Ministry of Education, Xiangya Hospital, Central South University, Changsha, PR China; Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Hunan 410008, PR China
| | - Qi Guo
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, Hunan 410008, PR China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan 410008, PR China; Key Laboratory of Aging-Related Bone and Joint Diseases Prevention and Treatment, Ministry of Education, Xiangya Hospital, Central South University, Changsha, PR China; Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Hunan 410008, PR China
| | - Hai-Yan Zhou
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, Hunan 410008, PR China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan 410008, PR China; Key Laboratory of Aging-Related Bone and Joint Diseases Prevention and Treatment, Ministry of Education, Xiangya Hospital, Central South University, Changsha, PR China; Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Hunan 410008, PR China.
| | - Xiang-Hang Luo
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, Hunan 410008, PR China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan 410008, PR China; Key Laboratory of Aging-Related Bone and Joint Diseases Prevention and Treatment, Ministry of Education, Xiangya Hospital, Central South University, Changsha, PR China; Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Hunan 410008, PR China.
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Baroi S, Czernik PJ, Khan MP, Letson J, Crowe E, Chougule A, Griffin PR, Rosen CJ, Lecka-Czernik B. PPARG in osteocytes controls cell bioenergetics and systemic energy metabolism independently of sclerostin levels in circulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.04.588029. [PMID: 38645043 PMCID: PMC11030235 DOI: 10.1101/2024.04.04.588029] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Objective The skeleton is one of the largest organs in the body, wherein metabolism is integrated with systemic energy metabolism. However, the bioenergetic programming of osteocytes, the most abundant bone cells coordinating bone metabolism, is not well defined. Here, using a mouse model with partial penetration of an osteocyte-specific PPARG deletion, we demonstrate that PPARG controls osteocyte bioenergetics and their contribution to systemic energy metabolism independently of circulating sclerostin levels. Methods In vivo and in vitro models of osteocyte-specific PPARG deletion, i.e. Dmp 1 Cre Pparγ flfl male and female mice (γOT KO ) and MLO-Y4 osteocyte-like cells with either siRNA-silenced or CRISPR/Cas9-edited Pparγ . As applicable, the models were analyzed for levels of energy metabolism, glucose metabolism, and metabolic profile of extramedullary adipose tissue, as well as the osteocyte transcriptome, mitochondrial function, bioenergetics, insulin signaling, and oxidative stress. Results Circulating sclerostin levels of γOT KO male and female mice were not different from control mice. Male γOT KO mice exhibited a high energy phenotype characterized by increased respiration, heat production, locomotion and food intake. This high energy phenotype in males did not correlate with "beiging" of peripheral adipose depots. However, both sexes showed a trend for reduced fat mass and apparent insulin resistance without changes in glucose tolerance, which correlated with decreased osteocytic responsiveness to insulin measured by AKT activation. The transcriptome of osteocytes isolated from γOT KO males suggested profound changes in cellular metabolism, fuel transport and usage, mitochondria dysfunction, insulin signaling and increased oxidative stress. In MLO-Y4 osteocytes, PPARG deficiency correlated with highly active mitochondria, increased ATP production, shifts in fuel utilization, and accumulation of reactive oxygen species (ROS). Conclusions PPARG in male osteocytes acts as a molecular break on mitochondrial function, and protection against oxidative stress and ROS accumulation. It also regulates osteocyte insulin signaling and fuel usage to produce energy. These data provide insight into the connection between osteocyte bioenergetics and their sex-specific contribution to the balance of systemic energy metabolism. These findings support the concept that the skeleton controls systemic energy expenditure via osteocyte metabolism. Highlights Osteocytes function as a body energostat via their bioenergeticsPPARG protein acts as a "molecular break" of osteocyte mitochondrial activityPPARG deficiency activates TCA cycle, oxidative stress and ROS accumulationPPARG controls osteocyte insulin signaling and fuel utilization.
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Zhang Y, Chen Q. Novel insights into osteocyte and inter-organ/tissue crosstalk. Front Endocrinol (Lausanne) 2024; 14:1308408. [PMID: 38685911 PMCID: PMC11057460 DOI: 10.3389/fendo.2023.1308408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 12/14/2023] [Indexed: 05/02/2024] Open
Abstract
Osteocyte, a cell type living within the mineralized bone matrix and connected to each other by means of numerous dendrites, appears to play a major role in body homeostasis. Benefiting from the maturation of osteocyte extraction and culture technique, many cross-sectional studies have been conducted as a subject of intense research in recent years, illustrating the osteocyte-organ/tissue communication not only mechanically but also biochemically. The present review comprehensively evaluates the new research work on the possible crosstalk between osteocyte and closely situated or remote vital organs/tissues. We aim to bring together recent key advances and discuss the mutual effect of osteocyte and brain, kidney, vascular calcification, muscle, liver, adipose tissue, and tumor metastasis and elucidate the therapeutic potential of osteocyte.
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Affiliation(s)
- Yan Zhang
- Department of Pediatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qingchang Chen
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Clinical Research Center for Medical Imaging in Hubei Province, Wuhan, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, China
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Wu K, Wang P, Deng L, Li Y, Zhang Q, Hou H, Zhu Y, Ye H, Mei S, Cui L. Analysis of bone metabolic alterations linked with osteoporosis progression in type 2 diabetic db/db mice. Exp Gerontol 2024; 185:112347. [PMID: 38097054 DOI: 10.1016/j.exger.2023.112347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 12/04/2023] [Accepted: 12/11/2023] [Indexed: 12/21/2023]
Abstract
Type 2 diabetes (T2D) is a common chronic disease, characterized by persistent hyperglycemia and insulin resistance. This disorder is associated with decreased bone quality and an elevated risk of bone fractures. However, evidence on the relationship between systemic metabolic change and the development of type 2 diabetic osteoporosis (T2DOP) remains elusive. Herein, we investigate the changes of bone metabolites with bone loss in db/db mice (an animal model of T2DOP exhibited bone loss with age progression), and explore the potential metabolic mechanism underlying type 2 diabetes and osteoporosis. C57BKS male mice were distributed in four groups, consisting six mice in each group: 8w m/m, 24w m/m, 8w db/db and 24w db/db. Bone morphometric and biomechanical parameters of db/db mice were analyzed by micro-CT and materials tester, it was found that 24w db/db mice showed severe bone loss and decreased bone tissue hardness compared with misty/misty littermates. The tibia of misty/misty mice (8 weeks, 24 weeks) and db/db mice (8 weeks, 24 weeks) were screened for differential metabolites by UPLC-Orbitrap MS. Ninety-eight metabolites were identified (35 and 63 metabolites are associated with early staged and late staged, respectively), consisting of amino acids, fatty acyls, and nucleotides. Notably, fatty acyls (such as 18-HEPE, 16(17)-EpDPE, arachidonic acid) and glycerophospholipids (such as phosphocholines (PC) (O-10:1(9E)/0:0), PC (O-16:1(9E)/0:0) [U] and phosphatidylethanolamines (PE) (P-16:0/0:0)) were significantly increased, and metabolites of amino acid pathway (such as l-glutamine, proline, phenylalanine) showed a downregulation trend. Dysregulation of lipid and glutathione pathways is the major contributor to progression of T2DOP in C57BKS mice.
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Affiliation(s)
- Kefeng Wu
- Marine Biomedical Research Institution of Guangdong Medical University, Guangdong Medical University, Zhanjiang 524023, PR China; Guangdong (Zhanjiang) provincial laboratory of Southern Marine Science and Engineering, Zhanjiang 524023, PR China.
| | - Pan Wang
- Marine Biomedical Research Institution of Guangdong Medical University, Guangdong Medical University, Zhanjiang 524023, PR China
| | - Luming Deng
- Marine Biomedical Research Institution of Guangdong Medical University, Guangdong Medical University, Zhanjiang 524023, PR China
| | - Yancai Li
- Marine Biomedical Research Institution of Guangdong Medical University, Guangdong Medical University, Zhanjiang 524023, PR China
| | - Qian Zhang
- Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang 524023, PR China
| | - Haiyan Hou
- Marine Biomedical Research Institution of Guangdong Medical University, Guangdong Medical University, Zhanjiang 524023, PR China
| | - Yuzhen Zhu
- Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang 524023, PR China; Guangdong (Zhanjiang) provincial laboratory of Southern Marine Science and Engineering, Zhanjiang 524023, PR China
| | - Hua Ye
- Marine Biomedical Research Institution of Guangdong Medical University, Guangdong Medical University, Zhanjiang 524023, PR China; Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang 524023, PR China
| | - Si Mei
- Marine Biomedical Research Institution of Guangdong Medical University, Guangdong Medical University, Zhanjiang 524023, PR China
| | - Liao Cui
- Marine Biomedical Research Institution of Guangdong Medical University, Guangdong Medical University, Zhanjiang 524023, PR China; Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang 524023, PR China.
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Kim SP, Seward AH, Garcia-Diaz J, Alekos N, Gould NR, Aja S, Stains JP, Wolfgang MJ, Riddle RC. Peroxisome proliferator activated receptor-γ in osteoblasts controls bone formation and fat mass by regulating sclerostin expression. iScience 2023; 26:106999. [PMID: 37534168 PMCID: PMC10391670 DOI: 10.1016/j.isci.2023.106999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/01/2023] [Accepted: 05/25/2023] [Indexed: 08/04/2023] Open
Abstract
The nuclear receptor peroxisome proliferator activated receptor-γ (PPARγ) is a key contributor to metabolic function via its adipogenic and insulin-sensitizing functions, but it has negative effects on skeletal homeostasis. Here, we questioned whether the skeletal and metabolic actions of PPARγ are linked. Ablating Pparg expression in osteoblasts and osteocytes produced a high bone mass phenotype, secondary to increased osteoblast activity, and a reduction in subcutaneous fat mass because of reduced fatty acid synthesis and increased fat oxidation. The skeletal and metabolic phenotypes in Pparg mutants proceed from the regulation of sclerostin production by PPARγ. Mutants exhibited reductions in skeletal Sost expression and serum sclerostin levels while increasing production normalized both phenotypes. Importantly, disrupting the production of sclerostin synergized with the insulin-sensitizing actions of a PPARγ agonist while preventing bone loss. These data suggest that modulating sclerostin action may prevent bone loss associated with anti-diabetic therapies and augment their metabolic actions.
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Affiliation(s)
- Soohyun P. Kim
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Avery H. Seward
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jean Garcia-Diaz
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Nathalie Alekos
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Nicole R. Gould
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Susan Aja
- Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Joseph P. Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Michael J. Wolfgang
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ryan C. Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Research and Development Service, Baltimore Veterans Administration Medical Center, Baltimore, MD 21201, USA
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Kitase Y, Prideaux M. Regulation of the Osteocyte Secretome with Aging and Disease. Calcif Tissue Int 2023; 113:48-67. [PMID: 37148298 DOI: 10.1007/s00223-023-01089-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 04/21/2023] [Indexed: 05/08/2023]
Abstract
As the most numerous and long-lived of all bone cells, osteocytes have essential functions in regulating skeletal health. Through the lacunar-canalicular system, secreted proteins from osteocytes can reach cells throughout the bone. Furthermore, the intimate connectivity between the lacunar-canalicular system and the bone vasculature allows for the transport of osteocyte-secreted factors into the circulation to reach the entire body. Local and endocrine osteocyte signaling regulates physiological processes such as bone remodeling, bone mechanoadaptation, and mineral homeostasis. However, these processes are disrupted by impaired osteocyte function induced by aging and disease. Dysfunctional osteocyte signaling is now associated with the pathogenesis of many disorders, including chronic kidney disease, cancer, diabetes mellitus, and periodontitis. In this review, we focus on the targeting of bone and extraskeletal tissues by the osteocyte secretome. In particular, we highlight the secreted osteocyte proteins, which are known to be dysregulated during aging and disease, and their roles during disease progression. We also discuss how therapeutic or genetic targeting of osteocyte-secreted proteins can improve both skeletal and systemic health.
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Affiliation(s)
- Yukiko Kitase
- Indiana Center for Musculoskeletal Health, School of Medicine, Indiana University, Indianapolis, IN, 46202, USA
- Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN, 46202, USA
| | - Matthew Prideaux
- Indiana Center for Musculoskeletal Health, School of Medicine, Indiana University, Indianapolis, IN, 46202, USA.
- Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN, 46202, USA.
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The Dopamine D1 Receptor Attenuates Titanium Particle-Induced Inhibition of Osteogenesis by Activating the Wnt Signaling Pathway. Mediators Inflamm 2023; 2023:6331650. [PMID: 36700172 PMCID: PMC9870688 DOI: 10.1155/2023/6331650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 12/20/2022] [Accepted: 12/31/2022] [Indexed: 01/18/2023] Open
Abstract
Periprosthetic osteolysis (PPO), caused by wear particles, has become a major cause of joint replacement failure. Secondary surgery after joint replacement poses a serious threat to public health worldwide. Therefore, determining how to effectively inhibit wear particle-induced PPO has become an urgent issue. Recently, the interaction between osteogenic inhibition and wear particles at the biological interface of the implant has been found to be an important factor in the pathological process. Previous studies have found that the central nervous system plays an important role in the regulation of bone formation and bone remodeling. Dopamine (DA), an important catecholamine neurotransmitter, plays an integral role in the physiological and pathological processes of various tissues through its corresponding receptors. Our current study found that upregulation of dopamine first receptors could be achieved by activating the Wnt/β-catenin pathway, improving osteogenesis in vivo and in vitro, and significantly reducing the inhibition of titanium particle-induced osteogenesis. Overall, these findings suggest that dopamine first receptor (D1R) may be a plausible target to promote osteoblast function and resist wear particle-induced PPO.
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Yao S, Du Z, Xiao L, Yan F, Ivanovski S, Xiao Y. Morphometric Changes of Osteocyte Lacunar in Diabetic Pig Mandibular Cancellous Bone. Biomolecules 2022; 13:biom13010049. [PMID: 36671434 PMCID: PMC9856050 DOI: 10.3390/biom13010049] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/12/2022] [Accepted: 12/13/2022] [Indexed: 12/29/2022] Open
Abstract
Osteocytes play an important role in bone metabolism. The interactions of osteocytes with the surrounding microenvironment can alter cellular and lacunar morphological changes. However, objective quantification of osteocyte lacunae is challenging due to their deep location in the bone matrix. This project established a novel method for the analytical study of osteocytes/lacunae, which was then used to evaluate the osteocyte morphological changes in diabetic pig mandibular bone. Eight miniature pigs were sourced, and diabetes was randomly induced in four animals using streptozotocin (STZ) administration. The mandibular tissues were collected and processed. The jawbone density was evaluated with micro-CT. Osteocyte lacunae were effectively acquired and identified using backscattered electron scanning microscopy (BSE). A significantly decreased osteocyte lacunae size was found in the diabetic group. Using the acid etching method, it was demonstrated that the area of osteocyte and lacunae, and the pericellular areas were both significantly reduced in the diabetes group. In conclusion, a standard and relatively reliable method for analyzing osteocyte/lacunae morphological changes under compromised conditions has been successfully established. This method demonstrates that diabetes can significantly decrease osteocyte/lacunae size in a pig's mandibular cancellous bone.
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Affiliation(s)
- Sheng Yao
- School of Mechanical, Medical and Process Engineering, Center of Biomedical Technology, Queensland University of Technology, Brisbane, QLD 4059, Australia
- The First Hospital of Wuhan, Wuhan 430033, China
| | - Zhibin Du
- School of Mechanical, Medical and Process Engineering, Center of Biomedical Technology, Queensland University of Technology, Brisbane, QLD 4059, Australia
| | - Lan Xiao
- School of Mechanical, Medical and Process Engineering, Center of Biomedical Technology, Queensland University of Technology, Brisbane, QLD 4059, Australia
- Australia-China Centre for Tissue Engineering and Regenerative Medicine, Queensland University of Technology, Brisbane, QLD 4059, Australia
| | - Fuhua Yan
- Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing 210008, China
| | - Saso Ivanovski
- School of Dentistry, The University of Queensland, Brisbane, QLD 4006, Australia
| | - Yin Xiao
- School of Mechanical, Medical and Process Engineering, Center of Biomedical Technology, Queensland University of Technology, Brisbane, QLD 4059, Australia
- Australia-China Centre for Tissue Engineering and Regenerative Medicine, Queensland University of Technology, Brisbane, QLD 4059, Australia
- School of Medicine and Dentistry & Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD 4222, Australia
- Correspondence:
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12
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Vadivalagan C, Krishnan A, Chen SJ, Hseu YC, Muthu S, Dhar R, Aljabali AAA, Tambuwala MM. The Warburg effect in osteoporosis: Cellular signaling and epigenetic regulation of energy metabolic events to targeting the osteocalcin for phenotypic alteration. Cell Signal 2022; 100:110488. [PMID: 36208706 DOI: 10.1016/j.cellsig.2022.110488] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 09/30/2022] [Accepted: 10/01/2022] [Indexed: 02/08/2023]
Abstract
Osteoporosis is a silent disease of skeletal morphology that induces fragility and fracture risk in aged persons irrespective of gender. Juvenile secondary osteoporosis is rare and is influenced by familial genetic abnormalities. Despite the currently available therapeutic options, more-acute treatments are in need. Women suffer from osteoporosis after menopause, which is characterized by a decline in the secretion of sex hormones in the later phase of life. Several studies in the past two decades emphasized hormone-related pathways to combat osteoporosis. Some studies partially examined energy-related pathways, but achieving a more vivid picture of metabolism and bone remodeling in terms of the Warburg phenomenon is still warranted. Each cell requires sufficient energy for cellular propagation and growth; in particular, osteoporosis is an energy-dependent mechanism affected by a decreased cellular mass of the bone morphology. Energy utilization is the actual propagation of such diseases, and narrowing down these criteria will hopefully provide clues to formulate better therapeutic strategies. Oxidative glycolysis is a particular type of energy metabolic pathway in cancer cells that influences cellular proliferation. Therefore, the prospect of utilizing collective glucose metabolism by inducing the Warburg effect may improve cell propagation. The benefits of utilizing the energy from the Warburg effect may be a difficult task. However, it seems to improve their effectiveness in the osteoblast phenotype by connecting the selected pathways such as WNT, Notch, AKT, and Insulin signaling by targeting osteocalcin resulting in phenotypic alteration. Osteocalcin directs ATP utilization through the sclerostin SOST gene in the bone microenvironment. Thus, selective activation of ATP production involved in osteoblast maturation remains a prime strategy to fight osteoporosis.
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Affiliation(s)
- Chithravel Vadivalagan
- Department of Cosmeceutics, College of Biopharmaceutical and Food Sciences, China Medical University, Taichung 40402, Taiwan.
| | - Anand Krishnan
- Department of Chemical Pathology, School of Pathology, Faculty of Health Sciences, University of the Free State, Bloemfontein 9300, South Africa.
| | - Siang-Jyun Chen
- Institute of Nutrition, College of Health Care, China Medical University, Taichung, 406040, Taiwan
| | - You-Cheng Hseu
- Department of Cosmeceutics, College of Biopharmaceutical and Food Sciences, China Medical University, Taichung 40402, Taiwan; Department of Health and Nutrition Biotechnology, Asia University, 41354, Taiwan; Chinese Medicine Research Center, China Medical University, Taichung 40402, Taiwan; Research Center of Chinese Herbal Medicine, China Medical University, Taichung 40402, Taiwan.
| | - Sathish Muthu
- Department of Orthopaedics, Government Medical College and Hospital, Dindigul-624003, Tamil Nadu, India
| | - Rajib Dhar
- Department of Genetic Engineering, SRM Institute of Science and Technology, Kattankulathur, -603203, Tamilnadu, India
| | - Alaa A A Aljabali
- Department of Pharmaceutics and Pharmaceutical Technology, Yarmouk University, Irbid, 21163, Jordan
| | - Murtaza M Tambuwala
- Lincoln Medical School, University of Lincoln, Brayford Pool Campus, Lincoln LN6 7TS, UK.
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13
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Abstract
Osteocytes, former osteoblasts encapsulated by mineralized bone matrix, are far from being passive and metabolically inactive bone cells. Instead, osteocytes are multifunctional and dynamic cells capable of integrating hormonal and mechanical signals and transmitting them to effector cells in bone and in distant tissues. Osteocytes are a major source of molecules that regulate bone homeostasis by integrating both mechanical cues and hormonal signals that coordinate the differentiation and function of osteoclasts and osteoblasts. Osteocyte function is altered in both rare and common bone diseases, suggesting that osteocyte dysfunction is directly involved in the pathophysiology of several disorders affecting the skeleton. Advances in osteocyte biology initiated the development of novel therapeutics interfering with osteocyte-secreted molecules. Moreover, osteocytes are targets and key distributors of biological signals mediating the beneficial effects of several bone therapeutics used in the clinic. Here we review the most recent discoveries in osteocyte biology demonstrating that osteocytes regulate bone homeostasis and bone marrow fat via paracrine signaling, influence body composition and energy metabolism via endocrine signaling, and contribute to the damaging effects of diabetes mellitus and hematologic and metastatic cancers in the skeleton.
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Affiliation(s)
- Jesus Delgado-Calle
- 1Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas,2Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Teresita Bellido
- 1Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas,2Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas,3Central Arkansas Veterans Healthcare System, Little Rock, Arkansas
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14
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Abstract
PURPOSE OF REVIEW In this review, we provide a recent update on bioenergetic pathways in osteocytes and identify potential future areas of research interest. Studies have identified a role for regulation of bone formation and bone resorption through osteocyte mechanosensing and osteocyte secreted factors. Nevertheless, there is a paucity of studies on the bioenergetics and energy metabolism of osteocytes, which are required for the regulation of bone remodeling. RECENT FINDINGS Osteocytes are cells of the osteoblast lineage embedded in bone. The osteocyte lacunocanalicular network within the skeletal matrix is exposed to a unique hypoxic environment. Therefore, the bioenergetic requirements of these cells could differ from other bone cells due to its location in the ossified matrix and its role in bone regulation transduced by mechanical signals. Recent findings highlighted in this review provide some evidence that metabolism of these cells is dependent on their location due to the substrates present in the microenvironment and metabolic cues from stress pathways. Both glycolysis (glucose metabolism) and oxidative phosphorylation (mitochondrial dynamics, ROS generation) affect osteocyte function and viability. In this review, we provide evidence that is currently available about information regarding bioenergetics pathways in osteocytes. We discuss published studies showing a role for hypoxia-driven glucose metabolism in regulating osteocyte bioenergetics. We also provide information on various substrates that osteocytes could utilize to fuel energetic needs, namely pyruvate, amino acids, and fatty acids. This is based on some preliminary experimental evidence that is available in literature. The role of parathyroid hormone PTH and parathryoid hormone-related peptide PTHrP in bone anabolism and resorption, along with regulation of metabolic pathways in the cells of the skeletal niche, needs to be explored further. Mitochondrial metabolism has a role in osteocyte bioenergetics through substrate utilization, location of the osteocyte in the bone cortex, and mitochondrial biogenesis. While there are limitations in studying metabolic flux in traditional cell lines, there are now novel cell lines and sophisticated tools available to study osteocyte bioenergetics to help harness its potential in vivo in the future.
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Affiliation(s)
- Vivin Karthik
- Center for Molecular Medicine, Maine Medical Center Research Institute, 81 Research Drive, Scarborough, ME, 04074, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
| | - Anyonya R Guntur
- Center for Molecular Medicine, Maine Medical Center Research Institute, 81 Research Drive, Scarborough, ME, 04074, USA.
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA.
- Tufts University School of Medicine, Tufts University, Boston, MA, USA.
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15
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Nováková S, Danchenko M, Okajčeková T, Baranovičová E, Kováč A, Grendár M, Beke G, Pálešová J, Strnádel J, Janíčková M, Halašová E, Škovierová H. Comparative Proteomic and Metabolomic Analysis of Human Osteoblasts, Differentiated from Dental Pulp Stem Cells, Hinted Crucial Signaling Pathways Promoting Osteogenesis. Int J Mol Sci 2021; 22:ijms22157908. [PMID: 34360674 PMCID: PMC8347416 DOI: 10.3390/ijms22157908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/18/2021] [Accepted: 07/20/2021] [Indexed: 12/11/2022] Open
Abstract
Population aging has been a global trend for the last decades, which increases the pressure to develop new cell-based or drug-based therapies, including those that may cure bone diseases. To understand molecular processes that underlie bone development and turnover, we followed osteogenic differentiation of human dental pulp stem cells (DPSCs) using a specific induction medium. The differentiation process imitating in vivo osteogenesis is triggered by various signaling pathways and is associated with massive proteome and metabolome changes. Proteome was profiled by ultrahigh-performance liquid chromatography and comprehensively quantified by ion mobility-enhanced mass spectrometry. From 2667 reproducibly quantified and identified proteins, 432 were differentially abundant by strict statistic criteria. Metabolome profiling was carried out by nuclear magnetic resonance. From 27 detected metabolites, 8 were differentially accumulated. KEGG and MetaboAnalyst hinted metabolic pathways that may be involved in the osteogenic process. Enrichment analysis of differentially abundant proteins highlighted PPAR, FoxO, JAK-STAT, IL-17 signaling pathways, biosynthesis of thyroid hormones and steroids, mineral absorption, and fatty acid metabolism as processes with prominent impact on osteoinduction. In parallel, metabolomic data showed that aminoacyl-tRNA biosynthesis, as well as specific amino acids, likely promote osteodifferentiation. Targeted immunoassays validated and complemented omic results. Our data underlined the complexity of the osteogenic mechanism. Finally, we proposed promising targets for future validation in patient samples, a step toward the treatment of bone defects.
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Affiliation(s)
- Slavomíra Nováková
- Biomedical Centre Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava (JFM CU), Malá Hora 4C, 036 01 Martin, Slovakia; (T.O.); (E.B.); (M.G.); (J.P.); (J.S.); (E.H.)
- Correspondence: (S.N.); (H.Š.); Tel.: +421-43-2633-904 (S.N.); +421-43-2633-904 (H.Š.)
| | - Maksym Danchenko
- Plant Science and Biodiversity Center, Slovak Academy of Sciences, Dúbravská cesta 9, 845 23 Bratislava, Slovakia;
| | - Terézia Okajčeková
- Biomedical Centre Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava (JFM CU), Malá Hora 4C, 036 01 Martin, Slovakia; (T.O.); (E.B.); (M.G.); (J.P.); (J.S.); (E.H.)
| | - Eva Baranovičová
- Biomedical Centre Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava (JFM CU), Malá Hora 4C, 036 01 Martin, Slovakia; (T.O.); (E.B.); (M.G.); (J.P.); (J.S.); (E.H.)
| | - Andrej Kováč
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dúbravská cesta 9, 845 10 Bratislava, Slovakia;
| | - Marián Grendár
- Biomedical Centre Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava (JFM CU), Malá Hora 4C, 036 01 Martin, Slovakia; (T.O.); (E.B.); (M.G.); (J.P.); (J.S.); (E.H.)
| | - Gábor Beke
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia;
| | - Janka Pálešová
- Biomedical Centre Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava (JFM CU), Malá Hora 4C, 036 01 Martin, Slovakia; (T.O.); (E.B.); (M.G.); (J.P.); (J.S.); (E.H.)
| | - Ján Strnádel
- Biomedical Centre Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava (JFM CU), Malá Hora 4C, 036 01 Martin, Slovakia; (T.O.); (E.B.); (M.G.); (J.P.); (J.S.); (E.H.)
| | - Mária Janíčková
- Department of Stomatology and Maxillofacial Surgery, University Hospital in Martin and JFM CU, Kollárova 2, 036 01 Martin, Slovakia;
| | - Erika Halašová
- Biomedical Centre Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava (JFM CU), Malá Hora 4C, 036 01 Martin, Slovakia; (T.O.); (E.B.); (M.G.); (J.P.); (J.S.); (E.H.)
- Department of Medical Biology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava (JFM CU), Malá Hora 4C, 036 01 Martin, Slovakia
| | - Henrieta Škovierová
- Biomedical Centre Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava (JFM CU), Malá Hora 4C, 036 01 Martin, Slovakia; (T.O.); (E.B.); (M.G.); (J.P.); (J.S.); (E.H.)
- Correspondence: (S.N.); (H.Š.); Tel.: +421-43-2633-904 (S.N.); +421-43-2633-904 (H.Š.)
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16
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Wang D, Zhao T, Zhao Y, Yin Y, Huang Y, Cheng Z, Wang B, Liu S, Pan M, Sun D, Wang Z, Zhu G. PPARγ Mediates the Anti-Epithelial-Mesenchymal Transition Effects of FGF1 ΔHBS in Chronic Kidney Diseases via Inhibition of TGF-β1/SMAD3 Signaling. Front Pharmacol 2021; 12:690535. [PMID: 34149434 PMCID: PMC8209477 DOI: 10.3389/fphar.2021.690535] [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: 04/03/2021] [Accepted: 05/21/2021] [Indexed: 02/06/2023] Open
Abstract
Podocytes are essential components of the glomerular basement membrane. Epithelial-mesenchymal-transition (EMT) in podocytes results in proteinuria. Fibroblast growth factor 1 (FGF1) protects renal function against diabetic nephropathy (DN). In the present study, we showed that treatment with an FGF1 variant with decreased mitogenic potency (FGF1ΔHBS) inhibited podocyte EMT, depletion, renal fibrosis, and preserved renal function in two nephropathy models. Mechanistic studies revealed that the inhibitory effects of FGF1ΔHBS podocyte EMT were mediated by decreased expression of transforming growth factor β1 via upregulation of PPARγ. FGF1ΔHBS enhanced the interaction between PPARγ and SMAD3 and suppressed SMAD3 nuclei translocation. We found that the anti-EMT activities of FGF1ΔHBS were independent of glucose-lowering effects. These findings expand the potential uses of FGF1ΔHBS in the treatment of diseases associated with EMT.
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Affiliation(s)
- Dezhong Wang
- Institute of Life Sciences and Engineering Laboratory of Zhejiang Province for Pharmaceutical Development of Growth Factors, Wenzhou University, Wenzhou, China.,The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Tianyang Zhao
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Yushuo Zhao
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Yuan Yin
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Yuli Huang
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Zizhao Cheng
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Beibei Wang
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Sidan Liu
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Minling Pan
- Institute of Life Sciences and Engineering Laboratory of Zhejiang Province for Pharmaceutical Development of Growth Factors, Wenzhou University, Wenzhou, China
| | - Difei Sun
- Institute of Life Sciences and Engineering Laboratory of Zhejiang Province for Pharmaceutical Development of Growth Factors, Wenzhou University, Wenzhou, China
| | - Zengshou Wang
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Guanghui Zhu
- The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.,The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
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17
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Baroi S, Czernik PJ, Chougule A, Griffin PR, Lecka-Czernik B. PPARG in osteocytes controls sclerostin expression, bone mass, marrow adiposity and mediates TZD-induced bone loss. Bone 2021; 147:115913. [PMID: 33722775 PMCID: PMC8076091 DOI: 10.1016/j.bone.2021.115913] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/05/2021] [Accepted: 03/06/2021] [Indexed: 01/07/2023]
Abstract
The peroxisome proliferator activated receptor gamma (PPARG) nuclear receptor regulates energy metabolism and insulin sensitivity. In this study, we present novel evidence for an essential role of PPARG in the regulation of osteocyte function, and support for the emerging concept of the conjunction between regulation of energy metabolism and bone mass. We report that PPARG is essential for sclerostin production, a recently approved target to treat osteoporosis. Our mouse model of osteocyte-specific PPARG deletion (Dmp1CrePparγflfl or γOTKO) is characterized with increased bone mass and reduced bone marrow adiposity, which is consistent with upregulation of WNT signaling and increased bone forming activity of endosteal osteoblasts. An analysis of osteocytes derived from γOTKO and control mice showed an excellent correlation between PPARG and SOST/sclerostin at the transcript and protein levels. The 8 kb sequence upstream of Sost gene transcription start site possesses multiple PPARG binding elements (PPREs) with at least two of them binding PPARG with dynamics reflecting its activation with full agonist rosiglitazone and correlating with increased levels of Sost transcript and sclerostin protein expression (Pearson's r = 0.991, p = 0.001). Older γOTKO female mice are largely protected from TZD-induced bone loss providing proof of concept that PPARG in osteocytes can be pharmacologically targeted. These findings demonstrate that transcriptional activities of PPARG are essential for sclerostin expression in osteocytes and support consideration of targeting PPARG activities with selective modulators to treat osteoporosis.
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Affiliation(s)
- Sudipta Baroi
- Department of Orthopaedic Surgery, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America; Center for Diabetes and Endocrine Research, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America
| | - Piotr J Czernik
- Department of Physiology and Pharmacology, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America
| | - Amit Chougule
- Department of Orthopaedic Surgery, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America; Center for Diabetes and Endocrine Research, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America
| | - Patrick R Griffin
- The Scripps Research Institute, Jupiter, FL, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America
| | - Beata Lecka-Czernik
- Department of Orthopaedic Surgery, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America; Department of Physiology and Pharmacology, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America; Center for Diabetes and Endocrine Research, University of Toledo, College of Medicine and Life Sciences, Toledo, OH, United States of America.
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18
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Osteocytes as main responders to low-intensity pulsed ultrasound treatment during fracture healing. Sci Rep 2021; 11:10298. [PMID: 33986415 PMCID: PMC8119462 DOI: 10.1038/s41598-021-89672-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/29/2021] [Indexed: 12/11/2022] Open
Abstract
Ultrasound stimulation is a type of mechanical stress, and low-intensity pulsed ultrasound (LIPUS) devices have been used clinically to promote fracture healing. However, it remains unclear which skeletal cells, in particular osteocytes or osteoblasts, primarily respond to LIPUS stimulation and how they contribute to fracture healing. To examine this, we utilized medaka, whose bone lacks osteocytes, and zebrafish, whose bone has osteocytes, as in vivo models. Fracture healing was accelerated by ultrasound stimulation in zebrafish, but not in medaka. To examine the molecular events induced by LIPUS stimulation in osteocytes, we performed RNA sequencing of a murine osteocytic cell line exposed to LIPUS. 179 genes reacted to LIPUS stimulation, and functional cluster analysis identified among them several molecular signatures related to immunity, secretion, and transcription. Notably, most of the isolated transcription-related genes were also modulated by LIPUS in vivo in zebrafish. However, expression levels of early growth response protein 1 and 2 (Egr1, 2), JunB, forkhead box Q1 (FoxQ1), and nuclear factor of activated T cells c1 (NFATc1) were not altered by LIPUS in medaka, suggesting that these genes are key transcriptional regulators of LIPUS-dependent fracture healing via osteocytes. We therefore show that bone-embedded osteocytes are necessary for LIPUS-induced promotion of fracture healing via transcriptional control of target genes, which presumably activates neighboring cells involved in fracture healing processes.
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19
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Mukherjee S, Yun JW. Novel regulatory roles of UCP1 in osteoblasts. Life Sci 2021; 276:119427. [PMID: 33785331 DOI: 10.1016/j.lfs.2021.119427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/17/2021] [Accepted: 03/22/2021] [Indexed: 11/28/2022]
Abstract
AIMS The bone-adipose axis requires complex homeostasis in energy and global metabolism. The bioenergetics of bone establishes the necessary energy balance to coordinate endocrine functions that are affected by various factors and is not limited to matrix proteins only. UCP1 is an uncoupling protein of adipocytes, commonly known for its unique feature of promoting thermogenesis, mainly in brown fat; however, the effects of UCP1 in other cell types remain unreported. MAIN METHODS In the current study, we determined the roles of UCP1 in osteoblasts by silencing the Ucp1 gene in MC-3T3-E1 cells, as well as C3H10T1/2 mesenchymal stem cells, and explored its functional activities. KEY FINDINGS Our results demonstrate for the first time the presence of UCP1 in osteoblast cells. We identified that UCP1 regulates ATP and oxidative phosphorylation in MC-3T3-E1 cells. In addition, our data reveal that the lack of Ucp1 results in reduced expressions of regulatory proteins involved in scavenging of ROS by enhancing an autophagic event to balance osteogenic differentiation. SIGNIFICANCE In conclusion, this study highlights a novel perspective on the importance of UCP1 in bone cells.
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Affiliation(s)
- Sulagna Mukherjee
- Department of Biotechnology, Daegu University, Gyeongsan, Gyeongbuk 38453, Republic of Korea
| | - Jong Won Yun
- Department of Biotechnology, Daegu University, Gyeongsan, Gyeongbuk 38453, Republic of Korea.
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20
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Tangseefa P, Martin SK, Arthur A, Panagopoulos V, Page AJ, Wittert GA, Proud CG, Fitter S, Zannettino ACW. Deletion of Rptor in Preosteoblasts Reveals a Role for the Mammalian Target of Rapamycin Complex 1 (mTORC1) Complex in Dietary-Induced Changes to Bone Mass and Glucose Homeostasis in Female Mice. JBMR Plus 2021; 5:e10486. [PMID: 33977204 PMCID: PMC8101617 DOI: 10.1002/jbm4.10486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 02/22/2021] [Accepted: 02/28/2021] [Indexed: 12/11/2022] Open
Abstract
The mammalian target of rapamycin complex 1 (mTORC1) complex is the major nutrient sensor in mammalian cells that responds to amino acids, energy levels, growth factors, and hormones, such as insulin, to control anabolic and catabolic processes. We have recently shown that suppression of the mTORC1 complex in bone‐forming osteoblasts (OBs) improved glucose handling in male mice fed a normal or obesogenic diet. Mechanistically, this occurs, at least in part, by increasing OB insulin sensitivity leading to upregulation of glucose uptake and glycolysis. Given previously reported sex‐dependent differences observed upon antagonism of mTORC1 signaling, we investigated the metabolic and skeletal effects of genetic inactivation of preosteoblastic‐mTORC1 in female mice. Eight‐week‐old control diet (CD)‐fed Rptorob−/− mice had a low bone mass with a significant reduction in trabecular bone volume and trabecular number, reduced cortical bone thickness, and increased marrow adiposity. Despite no changes in body composition, CD‐fed Rptorob−/− mice exhibited significant lower fasting insulin and glucose levels and increased insulin sensitivity. Upon high‐fat diet (HFD) feeding, Rptorob−/− mice were resistant to a diet‐induced increase in whole‐body and total fat mass and protected from the development of diet‐induced insulin resistance. Notably, although 12 weeks of HFD increased marrow adiposity, with minimal changes in both trabecular and cortical bone in the female control mice, marrow adiposity was significantly reduced in HFD‐fed Rptorob−/− compared to both HFD‐fed control and CD‐fed Rptorob−/− mice. Collectively, our results demonstrate that mTORC1 function in preosteoblasts is crucial for skeletal development and skeletal regulation of glucose homeostasis in both male and female mice. Importantly, loss of mTORC1 function in OBs results in metabolic and physiological adaptations that mirror a caloric restriction phenotype (under CD) and protects against HFD‐induced obesity, associated insulin resistance, and marrow adiposity expansion. These results highlight the critical contribution of the skeleton in the regulation of whole‐body energy homeostasis. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Pawanrat Tangseefa
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia
| | - Sally K Martin
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia
| | - Agnieszka Arthur
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia
| | - Vasilios Panagopoulos
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia
| | - Amanda J Page
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Nutrition, Diabetes & Gut Health Program, Lifelong Health Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia
| | - Gary A Wittert
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Nutrition, Diabetes & Gut Health Program, Lifelong Health Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia.,Freemasons Foundation Centre for Men's Health University of Adelaide Adelaide South Australia Australia
| | - Christopher G Proud
- Nutrition, Diabetes & Gut Health Program, Lifelong Health Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia.,School of Biological Sciences, University of Adelaide Adelaide South Australia Australia
| | - Stephen Fitter
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia
| | - Andrew C W Zannettino
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia.,Central Adelaide Local Health Network Adelaide South Australia Australia
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21
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Chang B, Liu X. Osteon: Structure, Turnover, and Regeneration. TISSUE ENGINEERING PART B-REVIEWS 2021; 28:261-278. [PMID: 33487116 DOI: 10.1089/ten.teb.2020.0322] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bone is composed of dense and solid cortical bone and honeycomb-like trabecular bone. Although cortical bone provides the majority of mechanical strength for a bone, there are few studies focusing on cortical bone repair or regeneration. Osteons (the Haversian system) form structural and functional units of cortical bone. In recent years, emerging evidences have shown that the osteon structure (including osteocytes, lamellae, lacunocanalicular network, and Haversian canals) plays critical roles in bone mechanics and turnover. Therefore, reconstruction of the osteon structure is crucial for cortical bone regeneration. This article provides a systematic summary of recent advances in osteons, including the structure, function, turnover, and regenerative strategies. First, the hierarchical structure of osteons is illustrated and the critical functions of osteons in bone dynamics are introduced. Next, the modeling and remodeling processes of osteons at a cellular level and the turnover of osteons in response to mechanical loading and aging are emphasized. Furthermore, several bioengineering approaches that were recently developed to recapitulate the osteon structure are highlighted. Impact statement This review provides a comprehensive summary of recent advances in osteons, especially the roles in bone formation, remodeling, and regeneration. Besides introducing the hierarchical structure and critical functions of osteons, we elucidate the modeling and remodeling of osteons at a cellular level. Specifically, we highlight the bioengineering approaches that were recently developed to mimic the hierarchical structure of osteons. We expect that this review will provide informative insights and attract increasing attentions in orthopedic community, shedding light on cortical bone regeneration in the future.
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Affiliation(s)
- Bei Chang
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, USA
| | - Xiaohua Liu
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, USA
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22
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Xu X, Xu N, Wang Y, Chen J, Chen L, Zhang S, Chen J, Deng H, Luan X, Shen J. The longitudinal associations between bone mineral density and appendicular skeletal muscle mass in Chinese community-dwelling middle aged and elderly men. PeerJ 2021; 9:e10753. [PMID: 33552737 PMCID: PMC7821753 DOI: 10.7717/peerj.10753] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 12/19/2020] [Indexed: 11/20/2022] Open
Abstract
Background The present study aimed to investigate longitudinal associations between bone mineral densities (BMDs) and appendicular skeletal muscle (ASM) mass in different regions of the body using three different indicators, in Chinese community-dwelling middle-aged and elderly men. Methods A total of 1,343 men aged ≥ 40 years from a Chinese community were assessed at baseline (2014-2016), one-year follow-up (2016-2017; n = 648), two-year follow-up (2017-2018; n = 407), and three-year follow up (2018-2019; n = 208). At all the four time-points, measurements included ASM mass and BMDs for all regions of the body using dual-energy X-ray absorptiometry. A questionnaire was completed by patients and biochemical markers were assessed. We applied three different indicators to define ASM mass or lean mass respectively, including the appendicular skeletal muscle index (ASM adjusted by height, ASMI, according to the Asian Working Group for Sarcopenia), skeletal muscle index (ASM adjusted by weight, SMI, according to the International Working Group on Sarcopenia), and the appendicular skeletal muscle/body mass index (ratio of ASM and Body mass index (BMI), ASM/BMI, according to the Foundation for the National Institutes of Health). After adjusting for potential confounders, the generalized additive mixed model (GAMM) was used to analyze the trend in ASM mass over time, and to test the association between ASM mass and regional and whole-body BMDs. Results The incidence of low lean mass was 8.2% defined by ASMI, 16.3% defined by SMI, and 8.3% defined by ASM/BMI. There was a linear relationship between BMDs and ASM mass, and ASMI, ASM/BMI, and SMI gradually decreased with time. After adjusting for covariances, GAMM analysis determined longitudinal associations between BMDs and ASM mass by three indicators respectively: the skull BMD was negatively associated with ASM mass. For each unit increase in skull BMD, ASMI decreased by 0.28 kg/m2 (95% confidence interval (CI) [-0.39 to -0.16]), ASM/BMI decreased by 0.02 m2 (95% CI [-0.03 to -0.00]), and SMI decreased by 0.01% (95% CI[-0.01 to -0.00]). The remaining parameters (including whole-body mean BMD, thoracic spinal BMD, lumbar spinal BMD, hip BMD, femoral neck BMD, pelvic BMD, left arm BMD, right arm BMD, left leg BMD, right leg BMD) were positively correlated with ASM mass. The ASMI increased by 3.07 kg/m2for each unit increase in the femoral neck BMD (95% CI [2.31-3.84]). The ASM/BMI increased by 0.22 m2for each unit increase in the left arm BMD (95% CI [0.12-0.33]), and the SMI increased by 0.05% per unit increase in the left arm BMD (95% CI [0.02-0.08]). Conclusions Compared to ASMI and ASM/BMI, SMI was more sensitive to screen for the low lean mass. Skull BMD was negatively associated with ASM mass, while BMDs throughout the rest of the body were positively correlated with ASM mass among the middle-aged and elderly Chinese men.
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Affiliation(s)
- Xuejuan Xu
- Department of Endocrinology, Southern Medical University, Guangzhou, Guangdong, China.,Department of Endocrinology, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, China.,Department of Endocrinology, The First People's Hospital of Foshan, Foshan, Guangdong, China
| | - Nuo Xu
- Department of Endocrinology, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, Shandong, China
| | - Ying Wang
- Department of Nuclear Medicine, The First People's Hospital of Foshan, Foshan, Guangdong, China
| | - Jinsong Chen
- Department of Endocrinology, The First People's Hospital of Foshan, Foshan, Guangdong, China
| | - Lushi Chen
- Department of Health Care, The First People's Hospital of Foshan, Foshan, Guangdong, China
| | - Shengjian Zhang
- Department of Health Care, The First People's Hospital of Foshan, Foshan, Guangdong, China
| | - Jingxian Chen
- Department of Hematology, The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Hongwen Deng
- Center of Genomics and Bioinformatics, Tulane University, New Orleans, LA, United States of America.,Department of Biostatistics and Bioinformatics, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, United States of America
| | - Xiaojun Luan
- Department of Endocrinology, The First People's Hospital of Foshan, Foshan, Guangdong, China
| | - Jie Shen
- Department of Endocrinology, Southern Medical University, Guangzhou, Guangdong, China.,Department of Endocrinology, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, China
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23
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The mTORC1 complex in pre-osteoblasts regulates whole-body energy metabolism independently of osteocalcin. Bone Res 2021; 9:10. [PMID: 33551450 PMCID: PMC7868369 DOI: 10.1038/s41413-020-00123-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 09/23/2020] [Accepted: 10/26/2020] [Indexed: 12/13/2022] Open
Abstract
Overnutrition causes hyperactivation of mTORC1-dependent negative feedback loops leading to the downregulation of insulin signaling and development of insulin resistance. In osteoblasts (OBs), insulin signaling plays a crucial role in the control of systemic glucose homeostasis. We utilized mice with conditional deletion of Rptor to investigate how the loss of mTORC1 function in OB affects glucose metabolism under normal and overnutrition dietary states. Compared to the controls, chow-fed Rptorob−/− mice had substantially less fat mass and exhibited adipocyte hyperplasia. Remarkably, upon feeding with high-fat diet, mice with pre- and post-natal deletion of Rptor in OBs were protected from diet-induced obesity and exhibited improved glucose metabolism with lower fasting glucose and insulin levels, increased glucose tolerance and insulin sensitivity. This leanness and resistance to weight gain was not attributable to changes in food intake, physical activity or lipid absorption but instead was due to increased energy expenditure and greater whole-body substrate flexibility. RNA-seq revealed an increase in glycolysis and skeletal insulin signaling pathways, which correlated with the potentiation of insulin signaling and increased insulin-dependent glucose uptake in Rptor-knockout osteoblasts. Collectively, these findings point to a critical role for the mTORC1 complex in the skeletal regulation of whole-body glucose metabolism and the skeletal development of insulin resistance.
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24
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The muscle to bone axis (and viceversa): An encrypted language affecting tissues and organs and yet to be codified? Pharmacol Res 2021; 165:105427. [PMID: 33453372 DOI: 10.1016/j.phrs.2021.105427] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/20/2020] [Accepted: 01/10/2021] [Indexed: 12/15/2022]
Abstract
Skeletal muscles and bone tissue form the musculoskeletal apparatus, a complex system essential for the voluntary movement. The loss of muscle mass and muscle strength is often associated with a loss of bone mass, in a "hazardous duet" which implies the co-existence of sarcopenia-osteoporosis and exposes patients to a deterioration in quality of life and increased mortality. From the mechanostat theory to the recent definition of the osteosarcopenia syndrome, many aspects of muscle-bone interaction have been investigated in recent decades. The mechanical interaction is now accepted, considering the close anatomical relationship between the two tissues, however, much remains to be discovered regarding the biochemical muscle-bone interaction. Skeletal muscle has been defined as an endocrine organ capable of exerting an action on other tissues. Myokines, bioactive polypeptides released by the muscle, could represent the encrypted message in the communication between muscle and bone. These two tissues have a reciprocal influence on their metabolisms and respond in a similar way to the multiple external factors. The aim of this review is to stimulate the understanding of the encrypted language between muscle and bone, highlighting the role of catabolic pathways and oxidative stress in the musculoskeletal apparatus to elucidate the shared mechanisms and the similarity of response to the same stimuli by different tissues. Our understanding of muscle-bone interactions it could be useful to identify and develop new strategies to treat musculoskeletal diseases, together with pharmacological, nutritional and exercise-based approaches, which are already in use for the treatment of these pathologies.
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25
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Hou J, He C, He W, Yang M, Luo X, Li C. Obesity and Bone Health: A Complex Link. Front Cell Dev Biol 2020; 8:600181. [PMID: 33409277 PMCID: PMC7779553 DOI: 10.3389/fcell.2020.600181] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 11/30/2020] [Indexed: 12/12/2022] Open
Abstract
So far, the connections between obesity and skeleton have been extensively explored, but the results are inconsistent. Obesity is thought to affect bone health through a variety of mechanisms, including body weight, fat volume, bone formation/resorption, proinflammatory cytokines together with bone marrow microenvironment. In this review, we will mainly describe the effects of adipokines secreted by white adipose tissue on bone cells, as well as the interaction between brown adipose tissue, bone marrow adipose tissue, and bone metabolism. Meanwhile, this review also reviews the evidence for the effects of adipose tissue and its distribution on bone mass and bone-related diseases, along with the correlation between different populations with obesity and bone health. And we describe changes in bone metabolism in patients with anorexia nervosa or type 2 diabetes. In summary, all of these findings show that the response of skeleton to obesity is complex and depends on diversified factors, such as mechanical loading, obesity type, the location of adipose tissue, gender, age, bone sites, and secreted cytokines, and that these factors may exert a primary function in bone health.
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Affiliation(s)
- Jing Hou
- Department of Endocrinology, Endocrinology Research Center, The Xiangya Hospital of Central South University, Changsha, China
| | - Chen He
- Department of Endocrinology, Endocrinology Research Center, The Xiangya Hospital of Central South University, Changsha, China
| | - Wenzhen He
- Department of Endocrinology, Endocrinology Research Center, The Xiangya Hospital of Central South University, Changsha, China
| | - Mi Yang
- Department of Endocrinology, Endocrinology Research Center, The Xiangya Hospital of Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders (Xiangya Hospital), Changsha, China
- Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha, China
| | - Xianghang Luo
- Department of Endocrinology, Endocrinology Research Center, The Xiangya Hospital of Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders (Xiangya Hospital), Changsha, China
- Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha, China
| | - Changjun Li
- Department of Endocrinology, Endocrinology Research Center, The Xiangya Hospital of Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders (Xiangya Hospital), Changsha, China
- Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha, China
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26
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Almeida M, Kim H, Han L, Zhou D, Thostenson J, Porter RM, Ambrogini E, Manolagas SC, Jilka RL. Increased marrow adipogenesis does not contribute to age-dependent appendicular bone loss in female mice. Aging Cell 2020; 19:e13247. [PMID: 33048436 PMCID: PMC7681065 DOI: 10.1111/acel.13247] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 08/14/2020] [Accepted: 08/30/2020] [Indexed: 01/13/2023] Open
Abstract
Marrow adipocytes and osteoblasts differentiate from common mesenchymal progenitors in a mutually exclusive manner, and diversion of these progenitors toward adipocytes in old age has been proposed to account for the decline in osteoblasts and the development of involutional osteoporosis. This idea has been supported by evidence that thiazolidinedione (TZD)‐induced activation of PPARγ, the transcription factor required for adipocyte differentiation, increases marrow fat and causes bone loss. We functionally tested this hypothesis using C57BL/6J mice with conditional deletion of PPARγ from early mesenchymal progenitors targeted by the Prx1‐Cre transgene. Using a longitudinal littermate‐controlled study design, we observed that PPARγ is indispensable for TZD‐induced increase in marrow adipocytes in 6‐month‐old male mice, and age‐associated increase in marrow adipocytes in 22‐month‐old female mice. In contrast, PPARγ is dispensable for the loss of cortical and trabecular bone caused by TZD or old age. Instead, PPARγ restrains age‐dependent development of cortical porosity. These findings do not support the long‐standing hypothesis that increased marrow adipocyte differentiation contributes to bone loss in old age but reveal a novel role of mesenchymal cell PPARγ in the maintenance of cortical integrity.
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Affiliation(s)
- Maria Almeida
- Center for Osteoporosis and Metabolic Bone Diseases University of Arkansas for Medical Sciences Little Rock AR USA
| | - Ha‐Neui Kim
- Center for Osteoporosis and Metabolic Bone Diseases University of Arkansas for Medical Sciences Little Rock AR USA
| | - Li Han
- Center for Osteoporosis and Metabolic Bone Diseases University of Arkansas for Medical Sciences Little Rock AR USA
| | - Daohong Zhou
- Department of Pharmacodynamics College of Pharmacy University of Florida Gainesville FL USA
| | - Jeff Thostenson
- Department of Biostatistics University of Arkansas for Medical Sciences Little Rock AR USA
| | - Ryan M. Porter
- Center for Osteoporosis and Metabolic Bone Diseases University of Arkansas for Medical Sciences Little Rock AR USA
| | - Elena Ambrogini
- Center for Osteoporosis and Metabolic Bone Diseases University of Arkansas for Medical Sciences Little Rock AR USA
- The Central Arkansas Veterans Healthcare System Little Rock AR USA
| | - Stavros C. Manolagas
- Center for Osteoporosis and Metabolic Bone Diseases University of Arkansas for Medical Sciences Little Rock AR USA
- The Central Arkansas Veterans Healthcare System Little Rock AR USA
| | - Robert L. Jilka
- Center for Osteoporosis and Metabolic Bone Diseases University of Arkansas for Medical Sciences Little Rock AR USA
- The Central Arkansas Veterans Healthcare System Little Rock AR USA
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27
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Abstract
PURPOSE OF REVIEW The purpose of this review is to describe the current state of our thinking regarding bone-muscle interactions beyond the mechanical perspective. RECENT FINDINGS Recent and prior evidence has begun to dissect many of the molecular mechanisms that bone and muscle use to communicate with each other and to modify each other's function. Several signaling factors produced by muscle and bone have emerged as potential mediators of these biochemical/molecular interactions. These include muscle factors such as myostatin, Irisin, BAIBA, IL-6, and the IGF family and the bone factors FGF-23, Wnt1 and Wnt3a, PGE2, FGF9, RANKL, osteocalcin, and sclerostin. The identification of these signaling molecules and their underlying mechanisms offers the very real and exciting possibility that new pharmaceutical approaches can be developed that will permit the simultaneous treatments of diseases that often occur in combination, such as osteoporosis and sarcopenia.
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Affiliation(s)
- Nuria Lara-Castillo
- Department of Oral and Craniofacial Sciences, UMKC School of Dentistry, 650 East 25th Street, Kansas City, MO, 64108, USA
| | - Mark L Johnson
- Department of Oral and Craniofacial Sciences, UMKC School of Dentistry, 650 East 25th Street, Kansas City, MO, 64108, USA.
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28
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Alekos NS, Moorer MC, Riddle RC. Dual Effects of Lipid Metabolism on Osteoblast Function. Front Endocrinol (Lausanne) 2020; 11:578194. [PMID: 33071983 PMCID: PMC7538543 DOI: 10.3389/fendo.2020.578194] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 08/25/2020] [Indexed: 12/14/2022] Open
Abstract
The skeleton is a dynamic and metabolically active organ with the capacity to influence whole body metabolism. This newly recognized function has propagated interest in the connection between bone health and metabolic dysfunction. Osteoblasts, the specialized mesenchymal cells responsible for the production of bone matrix and mineralization, rely on multiple fuel sources. The utilization of glucose by osteoblasts has long been a focus of research, however, lipids and their derivatives, are increasingly recognized as a vital energy source. Osteoblasts possess the necessary receptors and catabolic enzymes for internalization and utilization of circulating lipids. Disruption of these processes can impair osteoblast function, resulting in skeletal deficits while simultaneously altering whole body lipid homeostasis. This article provides an overview of the metabolism of postprandial and stored lipids and the osteoblast's ability to acquire and utilize these molecules. We focus on the requirement for fatty acid oxidation and the pathways regulating this function as well as the negative impact of dyslipidemia on the osteoblast and skeletal health. These findings provide key insights into the nuances of lipid metabolism in influencing skeletal homeostasis which are critical to appreciate the extent of the osteoblast's role in metabolic homeostasis.
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Affiliation(s)
- Nathalie S. Alekos
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Megan C. Moorer
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Baltimore Veterans Administration Medical Center, Baltimore, MD, United States
| | - Ryan C. Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Baltimore Veterans Administration Medical Center, Baltimore, MD, United States
- *Correspondence: Ryan C. Riddle
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29
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Marofi F, Hassanzadeh A, Solali S, Vahedi G, Mousavi Ardehaie R, Salarinasab S, Aliparasti MR, Ghaebi M, Farshdousti Hagh M. Epigenetic mechanisms are behind the regulation of the key genes associated with the osteoblastic differentiation of the mesenchymal stem cells: The role of zoledronic acid on tuning the epigenetic changes. J Cell Physiol 2019; 234:15108-15122. [PMID: 30652308 DOI: 10.1002/jcp.28152] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 01/08/2019] [Indexed: 01/24/2023]
Abstract
Mesenchymal stem cells (MSCs) are multipotent stem cells and show distinct features such as capability for self-renewal and differentiation into several lineages of cells including osteoblasts, chondrocytes, and adipocytes. In this study, the methylation status of the promoter region of zinc finger and BTB domain containing 16 (ZBTB16), twist-related protein 1(Twist1), de novo DNA methyltransferases 3A (DNMT3A), SRY-box 9 (Sox9), osteocalcin (OCN), and peroxisome proliferator-activated receptor γ2 (PPARγ2) genes and their messenger RNA (mRNA) expression levels were evaluated during the osteoblastic differentiation of MSCs (ODMSCs). We planned two experimental groups including zoledronic acid (ZA)-treated and nontreated cells (negative control) which both were differentiated into the osteoblasts. Methylation level of DNA in the promoter regions was assayed by methylation-specific-quantitative polymerase chain reaction (MS-qPCR), and mRNA levels of the target inhibitory/stimulatory genes during osteoblastic differentiation of MSCs were measured using real-time PCR. During the experimental induction of ODMSCs, the mRNA expression of the OCN gene was upregulated and methylation level of its promoter region was decreased. Moreover, Sox9 and PPARγ2 mRNA levels were attenuated and their promoter regions methylation levels were significantly augmented. However, the mRNA expression of the DNMT3A was not affected during the ODMSCs though its methylation rate was increased. In addition, ZA could enhance the expression of the ZBTB16 and decrease its promoter regions methylation and on the opposite side, it diminished mRNA expression of Sox9, Twist1, and PPARγ2 genes and increased their methylation rates. Intriguingly, ZA did not show a significant impact on gene expression and methylation levels the OCN and DNMT3A. We found that methylation of the promoter regions of Sox9, OCN, and PPARγ2 genes might be one of the main mechanisms adjusting the genes expression during the ODMSCs. Furthermore, we noticed that ZA can accelerate the MSCs differentiation to the osteoblast cells via two regulatory processes; suppression of osteoblastic differentiation inhibitor genes including Sox9, Twist1, and PPARγ2, and through promotion of the ZBTB16 expression.
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Affiliation(s)
- Faroogh Marofi
- Department of Immunology, Division of Hematology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.,Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ali Hassanzadeh
- Department of Immunology, Division of Hematology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.,Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Saeed Solali
- Department of Immunology, Division of Hematology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.,Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ghasem Vahedi
- Department of Immunology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Reza Mousavi Ardehaie
- Department of Medical Genetic, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Sadegh Salarinasab
- Department of Biochemistry and Clinical Laboratories, Faculty of Medicine, Tabriz University of Medical Science, Tabriz, Iran
| | - Mohammad Reza Aliparasti
- Department of Immunology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mahnaz Ghaebi
- Department of Immunology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Majid Farshdousti Hagh
- Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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30
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Grammatiki M, Antonopoulou V, Kotsa K. Emerging incretin hormones actions: focus on bone metabolism. MINERVA ENDOCRINOL 2019; 44:264-272. [DOI: 10.23736/s0391-1977.19.03008-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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31
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Exercise-Dependent Modulation of Bone Metabolism and Bone Endocrine Function: New Findings and Therapeutic Perspectives. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/s42978-019-0010-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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32
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Kim SP, Da H, Li Z, Kushwaha P, Beil C, Mei L, Xiong WC, Wolfgang MJ, Clemens TL, Riddle RC. Lrp4 expression by adipocytes and osteoblasts differentially impacts sclerostin's endocrine effects on body composition and glucose metabolism. J Biol Chem 2019; 294:6899-6911. [PMID: 30842262 DOI: 10.1074/jbc.ra118.006769] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 02/23/2019] [Indexed: 01/10/2023] Open
Abstract
Sclerostin exerts profound local control over bone acquisition and also mediates endocrine communication between fat and bone. In bone, sclerostin's anti-osteoanabolic activity is enhanced by low-density lipoprotein receptor-related protein 4 (Lrp4), which facilitates its interaction with the Lrp5 and Lrp6 Wnt co-receptors. To determine whether Lrp4 similarly affects sclerostin's endocrine function, we examined body composition as well as glucose and fatty acid metabolism in mice rendered deficient of Lrp4 in the adipocyte (AdΔLrp4) or the osteoblast (ObΔLrp4). AdΔLrp4 mice exhibit a reduction in adipocyte hypertrophy and improved glucose and lipid homeostasis, marked by increased glucose and insulin tolerance and reduced serum fatty acids, and mirror the effect of sclerostin deficiency on whole-body metabolism. Indeed, epistasis studies place adipocyte-expressed Lrp4 and sclerostin in the same genetic cascade that regulates adipocyte function. Intriguingly, ObΔLrp4 mice, which exhibit dramatic increases in serum sclerostin, accumulate body fat and develop impairments in glucose tolerance and insulin sensitivity despite development of a high bone mass phenotype. These data indicate that expression of Lrp4 by both the adipocyte and osteoblast is required for normal sclerostin endocrine function and that the impact of sclerostin deficiency on adipocyte physiology is distinct from the effect on osteoblast function.
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Affiliation(s)
| | - Hao Da
- From the Departments of Orthopedic Surgery and
| | - Zhu Li
- From the Departments of Orthopedic Surgery and
| | | | - Conor Beil
- From the Departments of Orthopedic Surgery and
| | - Lin Mei
- the Department of Neuroscience, Case Western Reserve University Medical School, Cleveland, Ohio 44106, and
| | - Wen-Cheng Xiong
- the Department of Neuroscience, Case Western Reserve University Medical School, Cleveland, Ohio 44106, and
| | - Michael J Wolfgang
- Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Thomas L Clemens
- From the Departments of Orthopedic Surgery and.,the Baltimore Veterans Affairs Medical Center, Baltimore, Maryland 21201
| | - Ryan C Riddle
- From the Departments of Orthopedic Surgery and .,the Baltimore Veterans Affairs Medical Center, Baltimore, Maryland 21201
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33
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Promoting osteoblast proliferation on polymer bone substitutes with bone-like structure by combining hydroxyapatite and bioactive glass. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2019; 96:1-9. [DOI: 10.1016/j.msec.2018.11.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 08/14/2018] [Accepted: 11/03/2018] [Indexed: 12/30/2022]
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34
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Liu DM, Mosialou I, Liu JM. Bone: Another potential target to treat, prevent and predict diabetes. Diabetes Obes Metab 2018; 20:1817-1828. [PMID: 29687585 DOI: 10.1111/dom.13330] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/16/2018] [Accepted: 04/18/2018] [Indexed: 12/30/2022]
Abstract
Type 2 diabetes mellitus is now a worldwide health problem with increasing prevalence. Mounting efforts have been made to treat, prevent and predict this chronic disease. In recent years, increasing evidence from mice and clinical studies suggests that bone-derived molecules modulate glucose metabolism. This review aims to summarize our current understanding of the interplay between bone and glucose metabolism and to highlight potential new means of therapeutic intervention. The first molecule recognized as a link between bone and glucose metabolism is osteocalcin (OCN), which functions in its active form, that is, undercarboxylated OCN (ucOC). ucOC acts in promoting insulin expression and secretion, facilitating insulin sensitivity, and favouring glucose and fatty acid uptake and utilization. A second bone-derived molecule, lipocalin2, functions in suppressing appetite in mice through its action on the hypothalamus. Osteocytes, the most abundant cells in bone matrix, are suggested to act on the browning of white adipose tissue and energy expenditure through secretion of bone morphogenetic protein 7 and sclerostin. The involvement of bone resorption in glucose homeostasis has also been examined. However, there is evidence indicating the implication of the receptor activator of nuclear factor κ-B ligand, neuropeptide Y, and other known and unidentified bone-derived factors that function in glucose homeostasis. We summarize recent advances and the rationale for treating, preventing and predicting diabetes by skeleton intervention.
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Affiliation(s)
- Dong-Mei Liu
- Department of Rheumatology, ZhongShan Hospital, FuDan University, Shanghai, China
| | - Ioanna Mosialou
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Jian-Min Liu
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
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Abstract
Biological processes utilize energy and therefore must be prioritized based on fuel availability. Bone is no exception to this, and the benefit of remodeling when necessary outweighs the energy costs. Bone remodeling is important for maintaining blood calcium homeostasis, repairing micro cracks and fractures, and modifying bone structure so that it is better suited to withstand loading demands. Osteoclasts, osteoblasts, and osteocytes are the primary cells responsible for bone remodeling, although bone marrow adipocytes and other cells may also play an indirect role. There is a renewed interest in bone cell energetics because of the potential for these processes to be targeted for osteoporosis therapies. In contrast, due to the intimate link between bone and energy homeostasis, pharmaceuticals that treat metabolic disease or have metabolic side effects often have deleterious bone consequences. In this brief review, we will introduce osteoporosis, discuss how bone cells utilize energy to function, evidence for bone regulating whole body energy homeostasis, and some of the unanswered questions and opportunities for further research in the field.
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Affiliation(s)
- Katherine J Motyl
- 1 Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine, USA
| | - Anyonya R Guntur
- 2 Center for Clinical and Translational Research, Maine Medical Center Research Institute, Scarborough, Maine, USA
| | - Adriana Lelis Carvalho
- 3 Internal Medicine Department, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Clifford J Rosen
- 2 Center for Clinical and Translational Research, Maine Medical Center Research Institute, Scarborough, Maine, USA
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