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Zhao Z, Yan K, Guan Q, Guo Q, Zhao C. Mechanism and physical activities in bone-skeletal muscle crosstalk. Front Endocrinol (Lausanne) 2024; 14:1287972. [PMID: 38239981 PMCID: PMC10795164 DOI: 10.3389/fendo.2023.1287972] [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: 09/03/2023] [Accepted: 12/05/2023] [Indexed: 01/22/2024] Open
Abstract
Bone and skeletal muscle work in coordination to maintain the function of the musculoskeletal system, in which skeletal muscle contraction drives the movement of the bone lever system while bone provides insert sites for skeletal muscle through the bone-muscle junction. Existing evidence suggests that factors secreted by skeletal muscle and bone mediate the interaction between the two tissues. Herein, we focused on the relationship between skeletal muscle and bone and the underlying mechanism of the interaction. Exercise can promote bone strength and secrete osteocalcin and insulin-like growth factor I into the blood, thus improving muscle quality. In addition, exercise can also promote myostatin, interleukin-6, Irisin, and apelin in muscles to enter the blood so that they can act on bones to maintain the balance between bone absorption and bone formation. There is a special regulatory axis interleukin-6/osteocalcin between myokines and osteokines, which is mainly influenced by exercise. Therefore, we pay attention to the important factors in the bone-muscle intersection that are affected by exercise, which were found or their functions were expanded, which strengthened the connection between organs of the whole body, highlighting the importance of exercise and contributing to the diagnosis, prevention, and treatment of osteoporosis and sarcopenia in the clinic.
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Affiliation(s)
- Zhonghan Zhao
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Kai Yan
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Qiao Guan
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Qiang Guo
- Department of Orthopaedics, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Can Zhao
- College of Athletic Performance, Shanghai University of Sport, Shanghai, China
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2
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Zhang L, Guan Q, Wang Z, Feng J, Zou J, Gao B. Consequences of Aging on Bone. Aging Dis 2023:AD.2023.1115. [PMID: 38029404 DOI: 10.14336/ad.2023.1115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 11/16/2023] [Indexed: 12/01/2023] Open
Abstract
With the aging of the global population, the incidence of musculoskeletal diseases has been increasing, seriously affecting people's health. As people age, the microenvironment within skeleton favors bone resorption and inhibits bone formation, accompanied by bone marrow fat accumulation and multiple cellular senescence. Specifically, skeletal stem/stromal cells (SSCs) during aging tend to undergo adipogenesis rather than osteogenesis. Meanwhile, osteoblasts, as well as osteocytes, showed increased apoptosis, decreased quantity, and multiple functional limitations including impaired mechanical sensing, intercellular modulation, and exosome secretion. Also, the bone resorption function of macrophage-lineage cells (including osteoclasts and preosteoclasts) was significantly enhanced, as well as impaired vascularization and innervation. In this study, we systematically reviewed the effect of aging on bone and the within microenvironment (including skeletal cells as well as their intracellular structure variations, vascular structures, innervation, marrow fat distribution, and lymphatic system) caused by aging, and mechanisms of osteoimmune regulation of the bone environment in the aging state, and the causal relationship with multiple musculoskeletal diseases in addition with their potential therapeutic strategy.
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Affiliation(s)
- Lingli Zhang
- College of Athletic Performance, Shanghai University of Sport, Shanghai, China
| | - Qiao Guan
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Zhikun Wang
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Jie Feng
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Jun Zou
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Bo Gao
- Department of Orthopedic Surgery, Xijing Hospital, Air Force Medical University, Xi'an, China
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3
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Lee BS, Murray C, Liu J, Kim M, Hwang MS, Yueh T, Mansour M, Qamar S, Agarwal G, Kim DG. The myosin and RhoGAP MYO9B influences osteocyte dendrite growth and responses to mechanical stimuli. Front Bioeng Biotechnol 2023; 11:1243303. [PMID: 37675403 PMCID: PMC10477788 DOI: 10.3389/fbioe.2023.1243303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/11/2023] [Indexed: 09/08/2023] Open
Abstract
Introduction: Myosin IXB (MYO9B) is an unconventional myosin with RhoGAP activity and thus is a regulator of actin cytoskeletal organization. MYO9B was previously shown to be necessary for skeletal growth and health and to play a role in actin-based functions of both osteoblasts and osteoclasts. However, its role in responses to mechanical stimulation of bone cells has not yet been described. Therefore, experiments were undertaken to determine the role of MYO9B in bone cell responses to mechanical stress both in vitro and in vivo. Methods: MYO9B expression was knocked down in osteoblast and osteocyte cell lines using RNA interference and the resulting cells were subjected to mechanical stresses including cyclic tensile strain, fluid shear stress, and plating on different substrates (no substrate vs. monomeric or polymerized collagen type I). Osteocytic cells were also subjected to MYO9B regulation through Slit-Robo signaling. Further, wild-type or Myo9b -/- mice were subjected to a regimen of whole-body vibration (WBV) and changes in bone quality were assessed by micro-CT. Results: Unlike control cells, MYO9B-deficient osteoblastic cells subjected to uniaxial cyclic tensile strain were unable to orient their actin stress fibers perpendicular to the strain. Osteocytic cells in which MYO9B was knocked down exhibited elongated dendrites but were unable to respond normally to treatments that increase dendrite length such as fluid shear stress and Slit-Robo signaling. Osteocytic responses to mechanical stimuli were also found to be dependent on the polymerization state of collagen type I substrates. Wild-type mice responded to WBV with increased bone tissue mineral density values while Myo9b -/- mice responded with bone loss. Discussion: These results demonstrate that MYO9B plays a key role in mechanical stress-induced responses of bone cells in vitro and in vivo.
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Affiliation(s)
- Beth S. Lee
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Cynthia Murray
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Jie Liu
- Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH, United States
| | - Minji Kim
- Department of Orthodontics, Graduate School of Clinical Dentistry, Ewha Womans University, Seoul, Republic of Korea
| | - Min Sik Hwang
- Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH, United States
| | - Tina Yueh
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Myrna Mansour
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Sana Qamar
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Gunjan Agarwal
- Department of Mechanical and Aerospace Engineering, College of Engineering, The Ohio State University, Columbus, OH, United States
| | - Do-Gyoon Kim
- Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH, United States
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4
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Wong SK, Mohamad NV, Jayusman PA, Ibrahim N‘I. A Review on the Crosstalk between Insulin and Wnt/β-Catenin Signalling for Bone Health. Int J Mol Sci 2023; 24:12441. [PMID: 37569816 PMCID: PMC10419059 DOI: 10.3390/ijms241512441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023] Open
Abstract
A positive association between insulin resistance and osteoporosis has been widely established. However, crosstalk between the signalling molecules in insulin and Wingless (Wnt)/beta-(β-)catenin transduction cascades orchestrating bone homeostasis remains not well understood. The current review aims to collate the existing evidence, reporting (a) the expression of insulin signalling molecules involved in bone-related disorders and (b) the expression of Wnt/β-catenin signalling molecules involved in governing insulin homeostasis. The downstream effector molecule, glycogen synthase kinase-3 beta (GSK3β), has been identified to be a point of convergence linking the two signal transduction networks. This review highlights that GSK3β may be a drug target in the development of novel anabolic agents and the potential use of GSK3β inhibitors to treat bone-related disorders.
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Affiliation(s)
- Sok Kuan Wong
- Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Bandar Tun Razak, Cheras, Kuala Lumpur 56000, Malaysia;
| | - Nur Vaizura Mohamad
- Centre for Drug and Herbal Development, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia;
| | - Putri Ayu Jayusman
- Department of Craniofacial Diagnostics and Biosciences, Faculty of Dentistry, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia;
| | - Nurul ‘Izzah Ibrahim
- Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Bandar Tun Razak, Cheras, Kuala Lumpur 56000, Malaysia;
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5
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Krasnova O, Neganova I. Assembling the Puzzle Pieces. Insights for in Vitro Bone Remodeling. Stem Cell Rev Rep 2023; 19:1635-1658. [PMID: 37204634 DOI: 10.1007/s12015-023-10558-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2023] [Indexed: 05/20/2023]
Abstract
As a highly dynamic organ, bone changes during throughout a person's life. This process is referred to as 'bone remodeling' and it involves two stages - a well-balanced osteoclastic bone resorption and an osteoblastic bone formation. Under normal physiological conditions bone remodeling is highly regulated that ensures tight coupling between bone formation and resorption, and its disruption results in a bone metabolic disorder, most commonly osteoporosis. Though osteoporosis is one of the most prevalent skeletal ailments that affect women and men aged over 40 of all races and ethnicities, currently there are few, if any safe and effective therapeutic interventions available. Developing state-of-the-art cellular systems for bone remodeling and osteoporosis can provide important insights into the cellular and molecular mechanisms involved in skeletal homeostasis and advise better therapies for patients. This review describes osteoblastogenesis and osteoclastogenesis as two vital processes for producing mature, active bone cells in the context of interactions between cells and the bone matrix. In addition, it considers current approaches in bone tissue engineering, pointing out cell sources, core factors and matrices used in scientific practice for modeling bone diseases and testing drugs. Finally, it focuses on the challenges that bone regenerative medicine is currently facing.
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Affiliation(s)
- O Krasnova
- Institute of Cytology, Russian Academy of Sciences, Saint-Petersburg, Russia
| | - I Neganova
- Institute of Cytology, Russian Academy of Sciences, Saint-Petersburg, Russia.
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6
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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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7
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Bi R, Luo X, Li Q, Li P, Li H, Fan Y, Ying B, Zhu S. Igf1 Regulates Fibrocartilage Stem Cells, Cartilage Growth, and Homeostasis in the Temporomandibular Joint of Mice. J Bone Miner Res 2023; 38:556-567. [PMID: 36722289 DOI: 10.1002/jbmr.4782] [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: 06/07/2022] [Revised: 01/19/2023] [Accepted: 01/27/2023] [Indexed: 02/02/2023]
Abstract
Temporomandibular joint (TMJ) growth requires orchestrated interactions between various cell types. Recent studies revealed that fibrocartilage stem cells (FCSCs) in the TMJ cartilage play critical roles as cell resources for joint development and repair. However, the detailed molecular network that influences FCSC fate during TMJ cartilage development remains to be elucidated. Here, we investigate the functional role of Igf1 in FCSCs for TMJ cartilage growth and homeostasis by lineage tracing using Gli1-CreER+ ; Tmflfl mice and conditional Igf1 deletion using Gli1-/Col2-CreER+ ; Igf1fl/fl mice. In Gli1-CreER+ ; Tmflfl mice, red fluorescence+ (RFP+ ) FCSCs show a favorable proliferative capacity. Igf1 deletion in Gli1+ /Col2+ cell lineages leads to distinct pathological changes in TMJ cartilage. More serious cartilage thickness and cell density reductions are found in the superficial layers in Gli1-CreER+ ; Igf1fl/fl mice. After long-term Igf1 deletion, a severe disordered cell arrangement is found in both groups. When Igf1 is conditionally deleted in vivo, the red fluorescent protein-labeled Gli1+ FCSC shows a significant disruption of chondrogenic differentiation, cell proliferation, and apoptosis leading to TMJ cartilage disarrangement and subchondral bone loss. Immunostaining shows that pAkt signaling is blocked in all cartilage layers after the Gli1+ -specific deletion of Igf1. In vitro, Igf1 deletion disrupts FCSC capacities, including proliferation and chondrogenesis. Moreover, the deletion of Igf1 in FCSCs significantly aggravates the joint osteoarthritis phenotype in the unilateral anterior crossbite mouse model, characterized by decreased cartilage thickness and cell numbers as well as a loss of extracellular matrix secretions. These findings uncover Igf1 as a regulator of TMJ cartilage growth and repair. The deletion of Igf1 disrupts the progenitor capacity of FCSCs, leading to a disordered cell distribution and exaggerating TMJ cartilage dysfunction. © 2023 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Ruiye Bi
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthognathic and TMJ Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xueting Luo
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthognathic and TMJ Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qianli Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthognathic and TMJ Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Peiran Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthognathic and TMJ Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Haohan Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthognathic and TMJ Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yi Fan
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthognathic and TMJ Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Binbin Ying
- Department of Stomatology, Ningbo First Hospital, Ningbo, China
| | - Songsong Zhu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthognathic and TMJ Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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8
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Kalyanaraman H, China SP, Cabriales JA, Moininazeri J, Casteel DE, Garcia JJ, Wong VW, Chen A, Sah RL, Boss GR, Pilz RB. Protein Kinase G2 Is Essential for Skeletal Homeostasis and Adaptation to Mechanical Loading in Male but Not Female Mice. J Bone Miner Res 2023; 38:171-185. [PMID: 36371651 PMCID: PMC9825661 DOI: 10.1002/jbmr.4746] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 11/04/2022] [Accepted: 11/10/2022] [Indexed: 11/14/2022]
Abstract
We previously showed that the NO/cGMP/protein kinase G (PKG) signaling pathway positively regulates osteoblast proliferation, differentiation, and survival in vitro, and that cGMP-elevating agents have bone-anabolic effects in mice. Here, we generated mice with an osteoblast-specific (OB) knockout (KO) of type 2 PKG (gene name Prkg2) using a Col1a1(2.3 kb)-Cre driver. Compared to wild type (WT) littermates, 8-week-old male OB Prkg2-KO mice had fewer osteoblasts, reduced bone formation rates, and lower trabecular and cortical bone volumes. Female OB Prkg2-KO littermates showed no bone abnormalities, despite the same degree of PKG2 deficiency in bone. Expression of osteoblast differentiation- and Wnt/β-catenin-related genes was lower in primary osteoblasts and bones of male KO but not female KO mice compared to WT littermates. Osteoclast parameters were unaffected in both sexes. Since PKG2 is part of a mechano-sensitive complex in osteoblast membranes, we examined its role during mechanical loading. Cyclical compression of the tibia increased cortical thickness and induced mechanosensitive and Wnt/β-catenin-related genes to a similar extent in male and female WT mice and female OB Prkg2-KO mice, but loading had a minimal effect in male KO mice. We conclude that PKG2 drives bone acquisition and adaptation to mechanical loading via the Wnt/β-catenin pathway in male mice. The striking sexual dimorphism of OB Prkg2-KO mice suggests that current U.S. Food and Drug Administration-approved cGMP-elevating agents may represent novel effective treatment options for male osteoporosis. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Hema Kalyanaraman
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- These two authors contributed equally to the work
| | - Shyamsundar Pal China
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- These two authors contributed equally to the work
| | - Justin A. Cabriales
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jafar Moininazeri
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Darren E. Casteel
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Julian J. Garcia
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Van W. Wong
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Albert Chen
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Robert L. Sah
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Gerry R. Boss
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Renate B. Pilz
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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9
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Gao L, Xu T, Zhang L, Li Y, Yan T, Yu G, Chen F. Midpalatal Suture: Single-Cell RNA-Seq Reveals Intramembrane Ossification and Piezo2 Chondrogenic Mesenchymal Cell Involvement. Cells 2022; 11:cells11223585. [PMID: 36429014 PMCID: PMC9688242 DOI: 10.3390/cells11223585] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/07/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
The midpalatal suture is mainly responsible for the growth and development of the maxillary and resistance to rapid maxillary expansion (RME). It is essential for clinical researchers to explore the intramembrane ossification and to elucidate the underlying mechanism of the maturation and ossification process of the midpalatal suture to help identify the optimum time and force of RME. However, mechanistic studies associated with the midpalatal suture are rare. The aim of this present study is to create an intramembrane osteogenesis model for the midpalatal suture region of mice. Interestingly, we discovered a type of chondrogenic mesenchymal cell expressing Piezo2, which might be related to the detection of mechanical and external stimuli. This result provides a potential molecular and cellular mechanism that explains why the midpalatal suture is not closed until adulthood. We depict a landscape of mesenchymal cells that might play an important role in the intramembrane osteogenesis of the midpalatal suture and provide new perspectives on midpalate suture maturation and ossification, which might lead to further possibilities for clinical operations.
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Affiliation(s)
- Lu Gao
- Central Laboratory, National Clinical Research Center for Oral Diseases, Peking University School and Hospital of Stomatology, Beijing 100081, China
- Department of Stomatology, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing 100045, China
| | - Tiansong Xu
- Central Laboratory, National Clinical Research Center for Oral Diseases, Peking University School and Hospital of Stomatology, Beijing 100081, China
| | - Liqi Zhang
- Central Laboratory, National Clinical Research Center for Oral Diseases, Peking University School and Hospital of Stomatology, Beijing 100081, China
| | - Yuchen Li
- Central Laboratory, National Clinical Research Center for Oral Diseases, Peking University School and Hospital of Stomatology, Beijing 100081, China
| | - Tianxing Yan
- Central Laboratory, National Clinical Research Center for Oral Diseases, Peking University School and Hospital of Stomatology, Beijing 100081, China
| | - Guoxia Yu
- Department of Stomatology, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing 100045, China
- Correspondence: (G.Y.); (F.C.)
| | - Feng Chen
- Central Laboratory, National Clinical Research Center for Oral Diseases, Peking University School and Hospital of Stomatology, Beijing 100081, China
- Correspondence: (G.Y.); (F.C.)
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10
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Bolamperti S, Villa I, Rubinacci A. Bone remodeling: an operational process ensuring survival and bone mechanical competence. Bone Res 2022; 10:48. [PMID: 35851054 PMCID: PMC9293977 DOI: 10.1038/s41413-022-00219-8] [Citation(s) in RCA: 91] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 05/02/2022] [Accepted: 05/15/2022] [Indexed: 12/12/2022] Open
Abstract
Bone remodeling replaces old and damaged bone with new bone through a sequence of cellular events occurring on the same surface without any change in bone shape. It was initially thought that the basic multicellular unit (BMU) responsible for bone remodeling consists of osteoclasts and osteoblasts functioning through a hierarchical sequence of events organized into distinct stages. However, recent discoveries have indicated that all bone cells participate in BMU formation by interacting both simultaneously and at different differentiation stages with their progenitors, other cells, and bone matrix constituents. Therefore, bone remodeling is currently considered a physiological outcome of continuous cellular operational processes optimized to confer a survival advantage. Bone remodeling defines the primary activities that BMUs need to perform to renew successfully bone structural units. Hence, this review summarizes the current understanding of bone remodeling and future research directions with the aim of providing a clinically relevant biological background with which to identify targets for therapeutic strategies in osteoporosis.
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Affiliation(s)
- Simona Bolamperti
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy
| | - Isabella Villa
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy
| | - Alessandro Rubinacci
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy.
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11
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Charoenphandhu N, Sooksawanwit S, Aeimlapa R, Thonapan N, Upanan P, Adulyaritthikul P, Krungchanuchat S, Panupinthu N, Teerapornpuntakit J, Rojviriya C, Lertsuwan K, Svasti S, Wongdee K. Mild-intensity physical activity prevents cardiac and osseous iron deposition without affecting bone mechanical property or porosity in thalassemic mice. Sci Rep 2022; 12:5959. [PMID: 35396390 PMCID: PMC8993875 DOI: 10.1038/s41598-022-09997-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 03/30/2022] [Indexed: 02/07/2023] Open
Abstract
Thalassemia causes anemia, ineffective erythropoiesis, bone loss and iron accumulation in several tissues, e.g., liver, bone and heart, the last of which leads to lethal cardiomyopathy and arrhythmia. Although exercise reportedly improves bone density in thalassemic mice, exercise performance is compromised and might pose risk of cardiovascular accident in thalassemic patients. Therefore, we sought to explore whether mild-intensity physical activity (MPA) with 30–50% of maximal oxygen consumption was sufficient to benefit the heart and bone. Herein, male hemizygous β-globin knockout (BKO) mice and wild-type littermates were subjected to voluntary wheel running 1 h/day, 5 days/week for 3 months (MPA group) or kept sedentary (SDN; control). As determined by atomic absorption spectroscopy, BKO-MPA mice had less iron accumulation in heart and bone tissues compared with BKO-SDN mice. Meanwhile, the circulating level of fibroblast growth factor-23—a factor known to reduce serum iron and intestinal calcium absorption—was increased early in young BKO-MPA mice. Nevertheless, MPA did not affect duodenal calcium transport or body calcium retention. Although MPA restored the aberrant bone calcium-phosphorus ratio to normal range, it did not change vertebral calcium content or femoral mechanical properties. Microstructural porosity in tibia of BKO-MPA mice remained unaltered as determined by synchrotron radiation X-ray tomographic microscopy. In conclusion, MPA prevents cardiac and bone iron accumulation, which is beneficial to thalassemic patients with limited physical fitness or deteriorated cardiac performance. However, in contrast to moderate-intensity exercise, MPA does not improve bone mechanical properties or reduce bone porosity.
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Affiliation(s)
- Narattaphol Charoenphandhu
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, 73170, Thailand.,The Academy of Science, The Royal Society of Thailand, Bangkok, 10300, Thailand
| | - Supagarn Sooksawanwit
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Ratchaneevan Aeimlapa
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Natchayaporn Thonapan
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Molecular Medicine Graduate Program, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Pornpailin Upanan
- Faculty of Allied Health Sciences, Burapha University, Long-Hard Bangsaen Road, Chonburi, 20131, Thailand
| | - Punyanuch Adulyaritthikul
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Saowalak Krungchanuchat
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Nattapon Panupinthu
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Jarinthorn Teerapornpuntakit
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand
| | - Catleya Rojviriya
- Synchrotron Light Research Institute (Public Organization), Nakhon Ratchasima, 30000, Thailand
| | - Kornkamon Lertsuwan
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Saovaros Svasti
- Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, 73170, Thailand
| | - Kannikar Wongdee
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand. .,Faculty of Allied Health Sciences, Burapha University, Long-Hard Bangsaen Road, Chonburi, 20131, Thailand.
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12
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Ledwon JK, Vaca EE, Huang CC, Kelsey LJ, McGrath JL, Topczewski J, Gosain AK, Topczewska JM. Langerhans cells and SFRP2/Wnt/beta-catenin signalling control adaptation of skin epidermis to mechanical stretching. J Cell Mol Med 2022; 26:764-775. [PMID: 35019227 PMCID: PMC8817127 DOI: 10.1111/jcmm.17111] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 10/08/2021] [Accepted: 10/29/2021] [Indexed: 12/01/2022] Open
Abstract
Skin can be mechanically stimulated to grow through a clinical procedure called tissue expansion (TE). Using a porcine TE model, we determined that expansion promptly activates transcription of SFRP2 in skin and we revealed that in the epidermis, this protein is secreted by Langerhans cells (LCs). Similar to well‐known mechanosensitive genes, the increase in SFRP2 expression was proportional to the magnitude of tension, showing a spike at the apex of the expanded skin. This implies that SFRP2 might be a newly discovered effector of mechanotransduction pathways. In addition, we found that acute stretching induces accumulation of b‐catenin in the nuclei of basal keratinocytes (KCs) and LCs, indicating Wnt signalling activation, followed by cell proliferation. Moreover, TE‐activated LCs proliferate and migrate into the suprabasal layer of skin, suggesting that LCs rebuild their steady network within the growing epidermis. We demonstrated that in vitro hrSFRP2 treatment on KCs inhibits Wnt/b‐catenin signalling and stimulates KC differentiation. In parallel, we observed an accumulation of KRT10 in vivo in the expanded skin, pointing to TE‐induced, SFRP2‐augmented KC maturation. Overall, our results reveal that a network of LCs delivers SFRP2 across the epidermis to fine‐tune Wnt/b‐catenin signalling to restore epidermal homeostasis disrupted by TE.
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Affiliation(s)
- Joanna K Ledwon
- Department of Surgery, Plastic Surgery Division, Northwestern University Feinberg School of Medicine, Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
| | - Elbert E Vaca
- Department of Surgery, Plastic Surgery Division, Northwestern University Feinberg School of Medicine, Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
| | - Chiang C Huang
- University of Wisconsin, Joseph J Zilber School of Public Health, Milwaukee, Illinois, USA
| | - Lauren J Kelsey
- Department of Surgery, Plastic Surgery Division, Northwestern University Feinberg School of Medicine, Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
| | - Jennifer L McGrath
- Department of Surgery, Plastic Surgery Division, Northwestern University Feinberg School of Medicine, Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
| | - Jacek Topczewski
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
| | - Arun K Gosain
- Department of Surgery, Plastic Surgery Division, Northwestern University Feinberg School of Medicine, Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
| | - Jolanta M Topczewska
- Department of Surgery, Plastic Surgery Division, Northwestern University Feinberg School of Medicine, Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.,Department of Pediatrics, Northwestern University Feinberg School of Medicine, Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
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13
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Aguirre JI, Castillo EJ, Kimmel DB. Biologic and pathologic aspects of osteocytes in the setting of medication-related osteonecrosis of the jaw (MRONJ). Bone 2021; 153:116168. [PMID: 34487892 PMCID: PMC8478908 DOI: 10.1016/j.bone.2021.116168] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/02/2021] [Accepted: 08/31/2021] [Indexed: 02/08/2023]
Abstract
Medication-related osteonecrosis of the jaw (MRONJ) is a potentially severe, debilitating condition affecting patients with cancer and patients with osteoporosis who have been treated with powerful antiresorptives (pARs) or angiogenesis inhibitors (AgIs). Oral risk factors associated with the development of MRONJ include tooth extraction and inflammatory dental disease (e.g., periodontitis, periapical infection). In bone tissues, osteocytes play a bidirectional role in which they not only act as the "receiver" of systemic signals from blood vessels, such as hormones and drugs, or local signals from the mineralized matrix as it is deformed, but they also play a critical role as "transmitter" of signals to the cells that execute bone modeling and remodeling (osteoclasts, osteoblasts and lining cells). When the survival capacity of osteocytes is overwhelmed, they can die. Osteocyte death has been associated with several pathological conditions. Whereas the causes and mechanisms of osteocyte death have been studied in conditions like osteonecrosis of the femoral head (ONFH), few studies of the causes and mechanisms of osteocyte death have been done in MRONJ. The three forms of cell death that affect most of the different cells in the body (apoptosis, autophagy, and necrosis) have been recognized in osteocytes. Notably, necroptosis, a form of regulated cell death with "a necrotic cell death phenotype," has also been identified as a form of cell death in osteocytes under certain pathologic conditions. Improving the understanding of osteocyte death in MRONJ may be critical for preventing disease and developing treatment approaches. In this review, we intend to provide insight into the biology of osteocytes, cell death, in general, and osteocyte death, in particular, and discuss hypothetical mechanisms involved in osteocyte death associated with MRONJ.
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Affiliation(s)
- J I Aguirre
- Department of Physiological Sciences, University of Florida (UF), Gainesville, FL, United States of America.
| | - E J Castillo
- Department of Physiological Sciences, University of Florida (UF), Gainesville, FL, United States of America.
| | - D B Kimmel
- Department of Physiological Sciences, University of Florida (UF), Gainesville, FL, United States of America
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14
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McCarthy C, Camci-Unal G. Low Intensity Pulsed Ultrasound for Bone Tissue Engineering. MICROMACHINES 2021; 12:1488. [PMID: 34945337 PMCID: PMC8707172 DOI: 10.3390/mi12121488] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 11/24/2021] [Accepted: 11/28/2021] [Indexed: 12/16/2022]
Abstract
As explained by Wolff's law and the mechanostat hypothesis, mechanical stimulation can be used to promote bone formation. Low intensity pulsed ultrasound (LIPUS) is a source of mechanical stimulation that can activate the integrin/phosphatidylinositol 3-OH kinase/Akt pathway and upregulate osteogenic proteins through the production of cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2). This paper analyzes the results of in vitro and in vivo studies that have evaluated the effects of LIPUS on cell behavior within three-dimensional (3D) titanium, ceramic, and hydrogel scaffolds. We focus specifically on cell morphology and attachment, cell proliferation and viability, osteogenic differentiation, mineralization, bone volume, and osseointegration. As shown by upregulated levels of alkaline phosphatase and osteocalcin, increased mineral deposition, improved cell ingrowth, greater scaffold pore occupancy by bone tissue, and superior vascularization, LIPUS generally has a positive effect and promotes bone formation within engineered scaffolds. Additionally, LIPUS can have synergistic effects by producing the piezoelectric effect and enhancing the benefits of 3D hydrogel encapsulation, growth factor delivery, and scaffold modification. Additional research should be conducted to optimize the ultrasound parameters and evaluate the effects of LIPUS with other types of scaffold materials and cell types.
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Affiliation(s)
- Colleen McCarthy
- Department of Chemical Engineering, University of Massachusetts Lowell, One University Avenue, Lowell, MA 01854, USA;
| | - Gulden Camci-Unal
- Department of Chemical Engineering, University of Massachusetts Lowell, One University Avenue, Lowell, MA 01854, USA;
- Department of Surgery, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01605, USA
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15
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Smit TH. Closing the osteon: Do osteocytes sense strain rate rather than fluid flow? Bioessays 2021; 43:e2000327. [PMID: 34111316 DOI: 10.1002/bies.202000327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 05/28/2021] [Accepted: 06/02/2021] [Indexed: 11/05/2022]
Abstract
Osteons are cylindrical structures of bone created by matrix resorbing osteoclasts, followed by osteoblasts that deposit new bone. Osteons align with the principal loading direction and it is thought that the osteoclasts are directed by osteocytes, the mechanosensitive cells that reside inside the bone matrix. These osteocytes are presumably controlled by interstitial fluid flow, induced by the physiological loading of bones. Here I consider the stimulation of osteocytes while the osteon is closed by osteoblasts. In a conceptual finite element model, bone is considered a poro-elastic material and subjected to locomotion-induced loading conditions. It appears that the magnitude of flow is constant along the closing cone, while shear strain rate in the bone matrix diminishes linearly with the deposition of bone. This suggests that shear strain rate, rather than fluid flow, is the physical cue that controls osteocytes and bone deposition in newly formed osteons.
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Affiliation(s)
- Theodoor H Smit
- Department of Medical Biology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands.,Department of Orthopaedic Surgery, Amsterdam University Medical Centers, Amsterdam Movement Sciences Research Institute, Amsterdam, The Netherlands
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16
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Sun Y, Yuan Y, Wu W, Lei L, Zhang L. The effects of locomotion on bone marrow mesenchymal stem cell fate: insight into mechanical regulation and bone formation. Cell Biosci 2021; 11:88. [PMID: 34001272 PMCID: PMC8130302 DOI: 10.1186/s13578-021-00601-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 05/04/2021] [Indexed: 02/06/2023] Open
Abstract
Bone marrow mesenchymal stem cells (BMSCs) refer to a heterogeneous population of cells with the capacity for self-renewal. BMSCs have multi-directional differentiation potential and can differentiate into chondrocytes, osteoblasts, and adipocytes under specific microenvironment or mechanical regulation. The activities of BMSCs are closely related to bone quality. Previous studies have shown that BMSCs and their lineage-differentiated progeny (for example, osteoblasts), and osteocytes are mechanosensitive in bone. Thus, a goal of this review is to discuss how these ubiquious signals arising from mechanical stimulation are perceived by BMSCs and then how the cells respond to them. Studies in recent years reported a significant effect of locomotion on the migration, proliferation and differentiation of BMSCs, thus, contributing to our bone mass. This regulation is realized by the various intersecting signaling pathways including RhoA/Rock, IFG, BMP and Wnt signalling. The mechanoresponse of BMSCs also provides guidance for maintaining bone health by taking appropriate exercises. This review will summarize the regulatory effects of locomotion/mechanical loading on BMSCs activities. Besides, a number of signalling pathways govern MSC fate towards osteogenic or adipocytic differentiation will be discussed. The understanding of mechanoresponse of BMSCs makes the foundation for translational medicine.
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Affiliation(s)
- Yuanxiu Sun
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang, China
| | - Yu Yuan
- School of Sport and Health, Guangzhou Sport University, Guangzhou, 510500, Guangdong, China
| | - Wei Wu
- School of Kinesiology, Shanghai University of Sport, Shanghai, 200438, China
| | - Le Lei
- School of Kinesiology, Shanghai University of Sport, Shanghai, 200438, China
| | - Lingli Zhang
- School of Physical Education & Sports Science, South China Normal University, 55 Zhongshan Road West, Tianhe District, Guangzhou, 510631, Guangdong, China.
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17
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Dodington DW, Yumol JL, Yang J, Pollock-Tahiri E, Sivasubramaniyam T, Sacco SM, Schroer SA, Li YE, Le H, Ward WE, Woo M. JAK2-IGF1 axis in osteoclasts regulates postnatal growth in mice. JCI Insight 2021; 6:137045. [PMID: 33682794 PMCID: PMC8021113 DOI: 10.1172/jci.insight.137045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 01/20/2021] [Indexed: 11/30/2022] Open
Abstract
Osteoclasts are specialized cells of the hematopoietic lineage that are responsible for bone resorption and play a critical role in musculoskeletal disease. JAK2 is a key mediator of cytokine and growth factor signaling; however, its role in osteoclasts in vivo has yet to be investigated. To elucidate the role of JAK2 in osteoclasts, we generated an osteoclast-specific JAK2-KO (Oc-JAK2-KO) mouse using the Cre/Lox-P system. Oc-JAK2-KO mice demonstrated marked postnatal growth restriction; however, this was not associated with significant changes in bone density, microarchitecture, or strength, indicating that the observed phenotype was not due to alterations in canonical osteoclast function. Interestingly, Oc-JAK2-KO mice had reduced osteoclast-specific expression of IGF1, suggesting a role for osteoclast-derived IGF1 in determination of body size. To directly assess the role of osteoclast-derived IGF1, we generated an osteoclast-specific IGF1-KO mouse, which showed a similar growth-restricted phenotype. Lastly, overexpression of circulating IGF1 by human transgene rescued the growth defects in Oc-JAK2-KO mice, in keeping with a causal role of IGF1 in these models. Together, our data show a potentially novel role for Oc-JAK2 and IGF1 in the determination of body size, which is independent of osteoclast resorptive function.
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Affiliation(s)
- David W. Dodington
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | | | - Jiaqi Yang
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Evan Pollock-Tahiri
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Tharini Sivasubramaniyam
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | | | - Stephanie A. Schroer
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Yujin E. Li
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Helen Le
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Wendy E. Ward
- Department of Kinesiology and
- Department of Health Sciences, Brock University, St. Catharines, Ontario, Canada
| | - Minna Woo
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Institute of Medical Science and Department of Immunology and
- Division of Endocrinology and Metabolism, Department of Medicine, University Health Network/Sinai Health System, University of Toronto, Toronto, Ontario, Canada
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18
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Pei F, Liu J, Zhang L, Pan X, Huang W, Cen X, Huang S, Jin Y, Zhao Z. The functions of mechanosensitive ion channels in tooth and bone tissues. Cell Signal 2020; 78:109877. [PMID: 33296740 DOI: 10.1016/j.cellsig.2020.109877] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/02/2020] [Accepted: 12/03/2020] [Indexed: 02/08/2023]
Abstract
Tooth and bone are independent tissues with a close relationship. Both are composed of a highly calcified outer structure and soft inner tissue, and both are constantly under mechanical stress. In particular, the alveolar bone and tooth constitute an occlusion system and suffer from masticatory and occlusal force. Thus, mechanotransduction is a key process in many developmental, physiological and pathological processes in tooth and bone. Mechanosensitive ion channels such as Piezo1 and Piezo2 are important participants in mechanotransduction, but their functions in tooth and bone are poorly understood. This review summarizes our current understanding of mechanosensitive ion channels and their roles in tooth and bone tissues. Research in these areas may shed new light on the regulation of tooth and bone tissues and potential treatments for diseases affecting these tissues.
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Affiliation(s)
- Fang Pei
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, PR China
| | - Jialing Liu
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, PR China
| | - Lan Zhang
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, PR China
| | - Xuefeng Pan
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, PR China
| | - Wei Huang
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, PR China
| | - Xiao Cen
- Department of the Temporomandibular Joint, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China
| | - Shishu Huang
- Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital, Sichuan University, Chengdu, PR China.
| | - Ying Jin
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, PR China.
| | - Zhihe Zhao
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, PR China.
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19
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Cao W, Helder MN, Bravenboer N, Wu G, Jin J, Ten Bruggenkate CM, Klein-Nulend J, Schulten EAJM. Is There a Governing Role of Osteocytes in Bone Tissue Regeneration? Curr Osteoporos Rep 2020; 18:541-550. [PMID: 32676786 PMCID: PMC7532966 DOI: 10.1007/s11914-020-00610-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE OF REVIEW Bone regeneration plays an important role in contemporary clinical treatment. Bone tissue engineering should result in successful bone regeneration to restore congenital or acquired bone defects in the human skeleton. Osteocytes are thought to have a governing role in bone remodeling by regulating osteoclast and osteoblast activity, and thus bone loss and formation. In this review, we address the so far largely unknown role osteocytes may play in bone tissue regeneration. RECENT FINDINGS Osteocytes release biochemical signaling molecules involved in bone remodeling such as prostaglandins, nitric oxide, Wnts, and insulin-like growth factor-1 (IGF-1). Treatment of mesenchymal stem cells in bone tissue engineering with prostaglandins (e.g., PGE2, PGI2, PGF2α), nitric oxide, IGF-1, or Wnts (e.g., Wnt3a) improves osteogenesis. This review provides an overview of the functions of osteocytes in bone tissue, their interaction with other bone cells, and their role in bone remodeling. We postulate that osteocytes may have a pivotal role in bone regeneration as well, and consequently that the bone regeneration process may be improved effectively and rapidly if osteocytes are optimally used and stimulated.
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Affiliation(s)
- Wei Cao
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
- Department of Oral and Maxillofacial Surgery/Oral Pathology, Amsterdam University Medical Centers and Academic Centre for Dentistry Amsterdam (ACTA), Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Marco N Helder
- Department of Oral and Maxillofacial Surgery/Oral Pathology, Amsterdam University Medical Centers and Academic Centre for Dentistry Amsterdam (ACTA), Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Nathalie Bravenboer
- Department of Clinical Chemistry, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Gang Wu
- Department of Oral Implantology and Prosthetic Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Jianfeng Jin
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
- Laboratory for Myology, Faculty of Behavioral and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Christiaan M Ten Bruggenkate
- Department of Oral and Maxillofacial Surgery/Oral Pathology, Amsterdam University Medical Centers and Academic Centre for Dentistry Amsterdam (ACTA), Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Jenneke Klein-Nulend
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Engelbert A J M Schulten
- Department of Oral and Maxillofacial Surgery/Oral Pathology, Amsterdam University Medical Centers and Academic Centre for Dentistry Amsterdam (ACTA), Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
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20
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3D Biomimetic Porous Titanium (Ti 6Al 4V ELI) Scaffolds for Large Bone Critical Defect Reconstruction: An Experimental Study in Sheep. Animals (Basel) 2020; 10:ani10081389. [PMID: 32796533 PMCID: PMC7459697 DOI: 10.3390/ani10081389] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 08/07/2020] [Accepted: 08/08/2020] [Indexed: 01/10/2023] Open
Abstract
Simple Summary The authors propose a new reconstructive technique that proved to be suitable to reach this purpose through the use of a custom-made biomimetic porous titanium scaffold. An in vivo study was undertaken where a complete critical defect was experimentally created in the diaphysis of the right tibia of twelve sheep and replaced with a five-centimeter porous scaffold of electron beam melting (EBM)-manufactured titanium alloy or a porous hydroxyapatite scaffold. Our results show that EBM-formed titanium devices, if used to repair critical bone defects in a large animal model, can guarantee immediate body weight-bearing, a rapid functional recovery, and a good osseointegration. The porous hydroxyapatite scaffolds proved to be not suitable in this model of large bone defect due to their known poor mechanical properties. Abstract The main goal in the treatment of large bone defects is to guarantee a rapid loading of the affected limb. In this paper, the authors proposed a new reconstructive technique that proved to be suitable to reach this purpose through the use of a custom-made biomimetic porous titanium scaffold. An in vivo study was undertaken where a complete critical defect was experimentally created in the diaphysis of the right tibia of twelve sheep and replaced with a five-centimeter porous scaffold of electron beam melting (EBM)-sintered titanium alloy (EBM group n = 6) or a porous hydroxyapatite scaffold (CONTROL group, n = 6). After surgery, the sheep were allowed to move freely in the barns. The outcome was monitored for up to 12 months by periodical X-ray and clinical examination. All animals in the CONTROL group were euthanized for humane reasons within the first month after surgery due to the onset of plate bending due to mechanical overload. Nine months after surgery, X-ray imaging showed the complete integration of the titanium implant in the tibia diaphysis and remodeling of the periosteal callus, with a well-defined cortical bone. At 12 months, sheep were euthanized, and the tibia were harvested and subjected to histological analysis. This showed bone tissue formations with bone trabeculae bridging titanium trabeculae, evidencing an optimal tissue-metal interaction. Our results show that EBM-sintered titanium devices, if used to repair critical bone defects in a large animal model, can guarantee immediate body weight-bearing, a rapid functional recovery, and a good osseointegration. The porous hydroxyapatite scaffolds proved to be not suitable in this model of large bone defect due to their known poor mechanical properties.
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21
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Bahamonde M, Misra M. Potential applications for rhIGF-I: Bone disease and IGFI. Growth Horm IGF Res 2020; 52:101317. [PMID: 32252004 PMCID: PMC7231643 DOI: 10.1016/j.ghir.2020.101317] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 03/09/2020] [Accepted: 03/21/2020] [Indexed: 12/18/2022]
Abstract
Growth hormone (GH) and insulin like growth factor-I (IGFI) are key bone trophic hormones, whose rising levels during puberty are critical for pubertal bone accrual. Conditions of GH deficiency and genetic resistance impact cortical and trabecular bone deleteriously with reduced estimates of bone strength. In humans, conditions of undernutrition (as in anorexia nervosa (AN), or subsequent to chronic illnesses) are associated with low IGF-I levels, which correlate with disease severity, and also with lower bone mineral density (BMD), impaired bone structure and lower strength estimates. In adolescents and adults with AN, studies have demonstrated a nutritionally acquired GH resistance with low IGF-I levels despite high concentrations of GH. IGF-I levels go up with increasing body weight, and are associated with rising levels of bone turnover markers. In short-term studies lasting 6-10 days, recombinant human IGF-I (rhIGF-I) administration in physiologic replacement doses normalized IGF-I levels and increased levels of bone formation markers in both adults and adolescents with AN. In a randomized controlled trial in adults with AN in which participants were randomized to one of four arms: (i) rhIGF-I with oral estrogen-progesterone (EP), (ii) rhIGF-I alone, (iii) EP alone, or (iv) neither for 9 months, a significant increase in bone formation markers was noted in the groups that received rhIGF-I, and a significant decrease in bone resorption markers in the groups that received EP. The group that received both rhIGF-I and EP had a significant increase in bone density at the spine and hip compared to the group that received neither. Side effects were minimal, with no documented fingerstick glucose of <50 mg/dl. These data thus suggest a potential role for rhIGF-I administration in optimizing bone accrual in states of undernutrition associated with low IGF-I.
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Affiliation(s)
- Marisol Bahamonde
- Department of Pediatrics, Universidad San Francisco de Quito (USFQ), Cumbayá, Ecuador
| | - Madhusmita Misra
- Division of Pediatric Endocrinology, Massachusetts General Hospital for Children, USA; Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA, USA.
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22
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Molina ER, Chim LK, Barrios S, Ludwig JA, Mikos AG. Modeling the Tumor Microenvironment and Pathogenic Signaling in Bone Sarcoma. TISSUE ENGINEERING. PART B, REVIEWS 2020; 26:249-271. [PMID: 32057288 PMCID: PMC7310212 DOI: 10.1089/ten.teb.2019.0302] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/07/2020] [Indexed: 12/17/2022]
Abstract
Investigations of cancer biology and screening of potential therapeutics for efficacy and safety begin in the preclinical laboratory setting. A staple of most basic research in cancer involves the use of tissue culture plates, on which immortalized cell lines are grown in monolayers. However, this practice has been in use for over six decades and does not account for vital elements of the tumor microenvironment that are thought to aid in initiation, propagation, and ultimately, metastasis of cancer. Furthermore, information gleaned from these techniques does not always translate to animal models or, more crucially, clinical trials in cancer patients. Osteosarcoma (OS) and Ewing sarcoma (ES) are the most common primary tumors of bone, but outcomes for patients with metastatic or recurrent disease have stagnated in recent decades. The unique elements of the bone tumor microenvironment have been shown to play critical roles in the pathogenesis of these tumors and thus should be incorporated in the preclinical models of these diseases. In recent years, the field of tissue engineering has leveraged techniques used in designing scaffolds for regenerative medicine to engineer preclinical tumor models that incorporate spatiotemporal control of physical and biological elements. We herein review the clinical aspects of OS and ES, critical elements present in the sarcoma microenvironment, and engineering approaches to model the bone tumor microenvironment. Impact statement The current paradigm of cancer biology investigation and therapeutic testing relies heavily on monolayer, monoculture methods developed over half a century ago. However, these methods often lack essential hallmarks of the cancer microenvironment that contribute to tumor pathogenesis. Tissue engineers incorporate scaffolds, mechanical forces, cells, and bioactive signals into biological environments to drive cell phenotype. Investigators of bone sarcomas, aggressive tumors that often rob patients of decades of life, have begun to use tissue engineering techniques to devise in vitro models for these diseases. Their efforts highlight how critical elements of the cancer microenvironment directly affect tumor signaling and pathogenesis.
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Affiliation(s)
- Eric R. Molina
- Department of Bioengineering, Rice University, Houston, Texas
| | - Letitia K. Chim
- Department of Bioengineering, Rice University, Houston, Texas
| | - Sergio Barrios
- Department of Bioengineering, Rice University, Houston, Texas
| | - Joseph A. Ludwig
- Division of Cancer Medicine, Department of Sarcoma Medical Oncology, MD Anderson Cancer Center, The University of Texas, Houston, Texas
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Yan Y, Wang L, Ge L, Pathak JL. Osteocyte-Mediated Translation of Mechanical Stimuli to Cellular Signaling and Its Role in Bone and Non-bone-Related Clinical Complications. Curr Osteoporos Rep 2020; 18:67-80. [PMID: 31953640 DOI: 10.1007/s11914-020-00564-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW Osteocytes comprise > 95% of the cellular component in bone tissue and produce a wide range of cytokines and cellular signaling molecules in response to mechanical stimuli. In this review, we aimed to summarize the molecular mechanisms involved in the osteocyte-mediated translation of mechanical stimuli to cellular signaling, and discuss their role in skeletal (bone) diseases and extra-skeletal (non-bone) clinical complications. RECENT FINDINGS Two decades before, osteocytes were assumed as a dormant cells buried in bone matrix. In recent years, emerging evidences have shown that osteocytes are pivotal not only for bone homeostasis but also for vital organ functions such as muscle, kidney, and heart. Osteocyte mechanotransduction regulates osteoblast and osteoclast function and maintains bone homeostasis. Mechanical stimuli modulate the release of osteocyte-derived cytokines, signaling molecules, and extracellular cellular vesicles that regulate not only the surrounding bone cell function and bone homeostasis but also the distant organ function in a paracrine and endocrine fashion. Mechanical loading and unloading modulate the osteocytic release of NO, PGE2, and ATPs that regulates multiple cellular signaling such as Wnt/β-catenin, RANKL/OPG, BMPs, PTH, IGF1, VEGF, sclerostin, and others. Therefore, the in-depth study of the molecular mechanism of osteocyte mechanotransduction could unravel therapeutic targets for various bone and non-bone-related clinical complications such as osteoporosis, sarcopenia, and cancer metastasis to bone.
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Affiliation(s)
- Yongyong Yan
- Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, 510140, China
| | - Liping Wang
- Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, 510140, China
| | - Linhu Ge
- Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, 510140, China.
| | - Janak L Pathak
- Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, 510140, China.
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Pathak JL, Bravenboer N, Klein-Nulend J. The Osteocyte as the New Discovery of Therapeutic Options in Rare Bone Diseases. Front Endocrinol (Lausanne) 2020; 11:405. [PMID: 32733380 PMCID: PMC7360678 DOI: 10.3389/fendo.2020.00405] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 05/20/2020] [Indexed: 01/18/2023] Open
Abstract
Osteocytes are the most abundant (~95%) cells in bone with the longest half-life (~25 years) in humans. In the past osteocytes have been regarded as vestigial cells in bone, since they are buried inside the tough bone matrix. However, during the last 30 years it has become clear that osteocytes are as important as bone forming osteoblasts and bone resorbing osteoclasts in maintaining bone homeostasis. The osteocyte cell body and dendritic processes reside in bone in a complex lacuno-canalicular system, which allows the direct networking of osteocytes to their neighboring osteocytes, osteoblasts, osteoclasts, bone marrow, blood vessels, and nerves. Mechanosensing of osteocytes translates the applied mechanical force on bone to cellular signaling and regulation of bone adaptation. The osteocyte lacuno-canalicular system is highly efficient in transferring external mechanical force on bone to the osteocyte cell body and dendritic processes via displacement of fluid in the lacuno-canalicular space. Osteocyte mechanotransduction regulates the formation and function of the osteoblasts and osteoclasts to maintain bone homeostasis. Osteocytes produce a variety of proteins and signaling molecules such as sclerostin, cathepsin K, Wnts, DKK1, DMP1, IGF1, and RANKL/OPG to regulate osteoblast and osteoclast activity. Various genetic abnormality-associated rare bone diseases are related to disrupted osteocyte functions, including sclerosteosis, van Buchem disease, hypophosphatemic rickets, and WNT1 and plastin3 mutation-related disorders. Meticulous studies during the last 15 years on disrupted osteocyte function in rare bone diseases guided for the development of various novel therapeutic agents to treat bone diseases. Studies on genetic, molecular, and cellular mechanisms of sclerosteosis and van Buchem disease revealed a role for sclerostin in bone homeostasis, which led to the development of the sclerostin antibody to treat osteoporosis and other bone degenerative diseases. The mechanism of many other rare bone diseases and the role of the osteocyte in the development of such conditions still needs to be investigated. In this review, we mainly discuss the knowledge obtained during the last 30 years on the role of the osteocyte in rare bone diseases. We speculate about future research directions to develop novel therapeutic drugs targeting osteocyte functions to treat both common and rare bone diseases.
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Affiliation(s)
- Janak L. Pathak
- Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Nathalie Bravenboer
- Department of Clinical Chemistry, Amsterdam University Medical Centers, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Jenneke Klein-Nulend
- Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam, Amsterdam Movement Sciences, University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- *Correspondence: Jenneke Klein-Nulend
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25
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Forceful mastication activates osteocytes and builds a stout jawbone. Sci Rep 2019; 9:4404. [PMID: 30890758 PMCID: PMC6424982 DOI: 10.1038/s41598-019-40463-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 02/14/2019] [Indexed: 12/13/2022] Open
Abstract
Bone undergoes a constant reconstruction process of resorption and formation called bone remodeling, so that it can endure mechanical loading. During food ingestion, masticatory muscles generate the required masticatory force. The magnitude of applied masticatory force has long been believed to be closely correlated with the shape of the jawbone. However, both the mechanism underlying this correlation and evidence of causation remain largely to be determined. Here, we established a novel mouse model of increased mastication in which mice were fed with a hard diet (HD) to elicit greater masticatory force. A novel in silico computer simulation indicated that the masticatory load onto the jawbone leads to the typical bone profile seen in the individuals with strong masticatory force, which was confirmed by in vivo micro-computed tomography (micro-CT) analyses. Mechanistically, increased mastication induced Insulin–like growth factor (IGF)-1 and suppressed sclerostin in osteocytes. IGF-1 enhanced osteoblastogenesis of the cells derived from tendon. Together, these findings indicate that the osteocytes balance the cytokine expression upon the mechanical loading of increased mastication, in order to enhance bone formation. This bone formation leads to morphological change in the jawbone, so that the bone adapts to the mechanical environment to which it is exposed.
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26
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Metzger CE, Narayanan SA. The Role of Osteocytes in Inflammatory Bone Loss. Front Endocrinol (Lausanne) 2019; 10:285. [PMID: 31139147 PMCID: PMC6527760 DOI: 10.3389/fendo.2019.00285] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 04/18/2019] [Indexed: 01/18/2023] Open
Abstract
Osteoimmunology investigations to-date have demonstrated the significant interactions between bone surface cells, osteoclasts and osteoblasts, and immune cells. However, there is a paucity of knowledge on osteocytes, cells embedded in the bone matrix, and their role in inflammation and inflammatory bone loss. Osteocytes communicate through various mechanisms; directly via dendritic processes and through secretion of proteins that can influence the formation and activity of osteoblasts and osteoclasts. Some osteocyte proteins (e.g., interleukin-6 and RANKL) also have roles within the immune system. In the context of mechanical loading/unloading, the regulatory role of osteocytes is well understood. More recent data on osteocytes in various inflammatory models suggest they may also aid in orchestrating inflammation-induced changes in bone turnover. In inflammatory conditions, osteocytes express multiple pro-inflammatory cytokines which are associated with increases in bone resorption and declines in bone formation. Cytokines are known to also influence cell population growth, maturation, and responsiveness via various signaling modalities, but how they influence osteocytes has not been greatly explored. Furthermore, osteocytes may play regulatory roles in orchestrating bone's response to immunological changes in inflammatory conditions. This review will address what is known about osteocyte biology in physiological conditions and in response to varying immunological conditions, as well as highlight key areas of interest for future investigations.
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Affiliation(s)
- Corinne E. Metzger
- Department of Health and Kinesiology, Texas A&M University, College Station, TX, United States
- *Correspondence: Corinne E. Metzger
| | - S. Anand Narayanan
- Department of Medical Physiology, Texas A&M Health Science Center, Bryan, TX, United States
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27
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Gao X, Lu A, Tang Y, Schneppendahl J, Liebowitz AB, Scibetta AC, Morris ER, Cheng H, Huard C, Amra S, Wang B, Hall MA, Lowe WR, Huard J. Influences of donor and host age on human muscle-derived stem cell-mediated bone regeneration. Stem Cell Res Ther 2018; 9:316. [PMID: 30463597 PMCID: PMC6249775 DOI: 10.1186/s13287-018-1066-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/14/2018] [Accepted: 11/05/2018] [Indexed: 01/08/2023] Open
Abstract
Background Human muscle-derived stem cells (hMDSCs) have been shown to regenerate bone efficiently when they were transduced with Lenti-viral bone morphogenetic protein 2 (LBMP2). However, whether the age of hMDSCs and the animal host affect the bone regeneration capacity of hMDSCs and mechanism are unknown which prompted the current study. Methods We isolated three gender-matched young and old populations of skeletal muscle stem cells, and tested the influence of cells’ age on in vitro osteogenic differentiation using pellet culture before and after Lenti-BMP2/green fluorescent protein (GFP) transduction. We further investigated effects of the age of hMDSCs and animal host on hMDSC-mediated bone regeneration in a critical-size calvarial bone defect model in vivo. Micro-computer tomography (CT), histology, and immunohistochemistry were used to evaluate osteogenic differentiation and mineralization in vitro and bone regeneration in vivo. Western blot, quantitative polymerase chain reaction (PCR), and oxidative stress assay were performed to detect the effects of age of hMDSCs on cell survival and osteogenic-related genes. Serum insulin-like growth factor 1 (IGF1) and receptor activator of nuclear factor-kappa B ligand (RANKL) were measured with an enzyme-linked immunosorbent assay (ELISA). Results We found LBMP2/GFP transduction significantly enhanced osteogenic differentiation of hMDSCs in vitro, regardless of donor age. We also found old were as efficient as young LBMP2/GFP-transduced hMDSCs for regenerating functional bone in young and old mice. These findings correlated with lower phosphorylated p38MAPK expression and similar expression levels of cell survival genes and osteogenic-related genes in old hMDSCs relative to young hMDSCs. Old cells exhibited equivalent resistance to oxidative stress. However, both young and old donor cells regenerated less bone in old than young hosts. Impaired bone regeneration in older hosts was associated with high bone remodeling due to higher serum levels of RANKL and lower level of IGF-1. Conclusion hMDSC-mediated bone regeneration was not impaired by donor age when hMDSCs were transduced with LBMP2/GFP, but the age of the host adversely affected hMDSC-mediated bone regeneration. Regardless of donor and host age, hMDSCs formed functional bone, suggesting a promising cell resource for bone regeneration. Electronic supplementary material The online version of this article (10.1186/s13287-018-1066-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xueqin Gao
- Department of Orthopaedic Surgery, University of Texas Health Science Center at Houston, Houston, TX, 77054, USA.,Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, 77054, USA.,Steadman Philippon Research Institute, Vail, CO, 81657, USA
| | - Aiping Lu
- Department of Orthopaedic Surgery, University of Texas Health Science Center at Houston, Houston, TX, 77054, USA.,Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, 77054, USA.,Steadman Philippon Research Institute, Vail, CO, 81657, USA
| | - Ying Tang
- Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, 15219, USA
| | | | | | | | | | - Haizi Cheng
- Department of Orthopaedic Surgery, University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
| | - Charles Huard
- Department of Orthopaedic Surgery, University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
| | - Sarah Amra
- Department of Orthopaedic Surgery, University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
| | - Bing Wang
- Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, 15219, USA
| | - Mary A Hall
- Department of Orthopaedic Surgery, University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
| | - Walter R Lowe
- Department of Orthopaedic Surgery, University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
| | - Johnny Huard
- Department of Orthopaedic Surgery, University of Texas Health Science Center at Houston, Houston, TX, 77054, USA. .,Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, 77054, USA. .,Steadman Philippon Research Institute, Vail, CO, 81657, USA.
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28
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Liu H, Zhu R, Wang L, Liu C, Ma R, Qi B, Chen B, Li L, Guo Y, Shi S, Jia Q, Niu J, Zhao D, Mo F, Gao S, Zhang D. Radix Salviae miltiorrhizae
improves bone microstructure and strength through Wnt/β-catenin and osteoprotegerin/receptor activator for nuclear factor-κB ligand/cathepsin K signaling in ovariectomized rats. Phytother Res 2018; 32:2487-2500. [DOI: 10.1002/ptr.6188] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 07/16/2018] [Accepted: 08/13/2018] [Indexed: 12/17/2022]
Affiliation(s)
- Haixia Liu
- Diabetes Research Center; Beijing University of Chinese Medicine; Beijing China
- Traditional Chinese Medicine School; Beijing University of Chinese Medicine; Beijing China
| | - Ruyuan Zhu
- Diabetes Research Center; Beijing University of Chinese Medicine; Beijing China
- Traditional Chinese Medicine School; Beijing University of Chinese Medicine; Beijing China
| | - Lili Wang
- Diabetes Research Center; Beijing University of Chinese Medicine; Beijing China
- Traditional Chinese Medicine School; Beijing University of Chinese Medicine; Beijing China
- Chinese Materia Medica School; Beijing University of Chinese Medicine; Beijing China
| | - Chenyue Liu
- Chinese Materia Medica School; Beijing University of Chinese Medicine; Beijing China
| | - Rufeng Ma
- Diabetes Research Center; Beijing University of Chinese Medicine; Beijing China
- Guang'anmen Hospital; China Academy of Chinese Medical Sciences; Beijing China
| | - Bowen Qi
- Chinese Materia Medica School; Beijing University of Chinese Medicine; Beijing China
| | - Beibei Chen
- Traditional Chinese Medicine School; Beijing University of Chinese Medicine; Beijing China
| | - Lin Li
- Traditional Chinese Medicine School; Beijing University of Chinese Medicine; Beijing China
| | - Yubo Guo
- Diabetes Research Center; Beijing University of Chinese Medicine; Beijing China
- The Third Affiliated Clinical Hospital; Beijing University of Chinese Medicine; Beijing China
| | - Shepo Shi
- Chinese Materia Medica School; Beijing University of Chinese Medicine; Beijing China
| | - Qiangqiang Jia
- Traditional Chinese Medicine School; Beijing University of Chinese Medicine; Beijing China
| | - Jianzhao Niu
- Traditional Chinese Medicine School; Beijing University of Chinese Medicine; Beijing China
| | - Dandan Zhao
- Diabetes Research Center; Beijing University of Chinese Medicine; Beijing China
- Traditional Chinese Medicine School; Beijing University of Chinese Medicine; Beijing China
| | - Fangfang Mo
- Diabetes Research Center; Beijing University of Chinese Medicine; Beijing China
- Traditional Chinese Medicine School; Beijing University of Chinese Medicine; Beijing China
| | - Sihua Gao
- Diabetes Research Center; Beijing University of Chinese Medicine; Beijing China
- Traditional Chinese Medicine School; Beijing University of Chinese Medicine; Beijing China
| | - Dongwei Zhang
- Diabetes Research Center; Beijing University of Chinese Medicine; Beijing China
- Traditional Chinese Medicine School; Beijing University of Chinese Medicine; Beijing China
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29
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Lindsey RC, Rundle CH, Mohan S. Role of IGF1 and EFN-EPH signaling in skeletal metabolism. J Mol Endocrinol 2018; 61:T87-T102. [PMID: 29581239 PMCID: PMC5966337 DOI: 10.1530/jme-17-0284] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 03/26/2018] [Indexed: 01/11/2023]
Abstract
Insulin-like growth factor 1(IGF1) and ephrin ligand (EFN)-receptor (EPH) signaling are both crucial for bone cell function and skeletal development and maintenance. IGF1 signaling is the major mediator of growth hormone-induced bone growth, but a host of different signals and factors regulate IGF1 signaling at the systemic and local levels. Disruption of the Igf1 gene results in reduced peak bone mass in both experimental animal models and humans. Additionally, EFN-EPH signaling is a complex system which, particularly through cell-cell interactions, contributes to the development and differentiation of many bone cell types. Recent evidence has demonstrated several ways in which the IGF1 and EFN-EPH signaling pathways interact with and depend upon each other to regulate bone cell function. While much remains to be elucidated, the interaction between these two signaling pathways opens a vast array of new opportunities for investigation into the mechanisms of and potential therapies for skeletal conditions such as osteoporosis and fracture repair.
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Affiliation(s)
- Richard C Lindsey
- Musculoskeletal Disease CenterVA Loma Linda Healthcare System, Loma Linda, California, USA
- Division of BiochemistryDepartment of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, California, USA
- Center for Health Disparities and Molecular MedicineDepartment of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, California, USA
| | - Charles H Rundle
- Musculoskeletal Disease CenterVA Loma Linda Healthcare System, Loma Linda, California, USA
- Department of MedicineLoma Linda University, Loma Linda, California, USA
| | - Subburaman Mohan
- Musculoskeletal Disease CenterVA Loma Linda Healthcare System, Loma Linda, California, USA
- Division of BiochemistryDepartment of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, California, USA
- Center for Health Disparities and Molecular MedicineDepartment of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, California, USA
- Department of MedicineLoma Linda University, Loma Linda, California, USA
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30
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Yakar S, Werner H, Rosen CJ. Insulin-like growth factors: actions on the skeleton. J Mol Endocrinol 2018; 61:T115-T137. [PMID: 29626053 PMCID: PMC5966339 DOI: 10.1530/jme-17-0298] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 04/06/2018] [Indexed: 12/20/2022]
Abstract
The discovery of the growth hormone (GH)-mediated somatic factors (somatomedins), insulin-like growth factor (IGF)-I and -II, has elicited an enormous interest primarily among endocrinologists who study growth and metabolism. The advancement of molecular endocrinology over the past four decades enables investigators to re-examine and refine the established somatomedin hypothesis. Specifically, gene deletions, transgene overexpression or more recently, cell-specific gene-ablations, have enabled investigators to study the effects of the Igf1 and Igf2 genes in temporal and spatial manners. The GH/IGF axis, acting in an endocrine and autocrine/paracrine fashion, is the major axis controlling skeletal growth. Studies in rodents have clearly shown that IGFs regulate bone length of the appendicular skeleton evidenced by changes in chondrocytes of the proliferative and hypertrophic zones of the growth plate. IGFs affect radial bone growth and regulate cortical and trabecular bone properties via their effects on osteoblast, osteocyte and osteoclast function. Interactions of the IGFs with sex steroid hormones and the parathyroid hormone demonstrate the significance and complexity of the IGF axis in the skeleton. Finally, IGFs have been implicated in skeletal aging. Decreases in serum IGFs during aging have been correlated with reductions in bone mineral density and increased fracture risk. This review highlights many of the most relevant studies in the IGF research landscape, focusing in particular on IGFs effects on the skeleton.
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Affiliation(s)
- Shoshana Yakar
- David B. Kriser Dental Center, Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010-4086, USA
| | - Haim Werner
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Clifford J Rosen
- Maine Medical Center Research Institute, Scarborough, Maine 04074, USA
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31
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Agostini G, Holt BM, Relethford JH. Bone functional adaptation does not erase neutral evolutionary information. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 166:708-729. [DOI: 10.1002/ajpa.23460] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 02/26/2018] [Accepted: 03/01/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Gina Agostini
- Mayo Clinic/ASU Obesity Solutions, School of Human Evolution and Social ChangeArizona State UniversityTempe Arizona
| | - Brigitte M. Holt
- Department of AnthropologyUniversity of Massachusetts AmherstAmherst Massachusetts
| | - John H. Relethford
- Department of AnthropologyState University of New York at OneontaOneonta New York
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32
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Tian F, Wang Y, Bikle DD. IGF-1 signaling mediated cell-specific skeletal mechano-transduction. J Orthop Res 2018; 36:576-583. [PMID: 28980721 PMCID: PMC5839951 DOI: 10.1002/jor.23767] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 09/27/2017] [Indexed: 02/04/2023]
Abstract
Mechanical loading preserves bone mass and stimulates bone formation, whereas skeletal unloading leads to bone loss. In addition to osteocytes, which are considered the primary sensor of mechanical load, osteoblasts, and bone specific mesenchymal stem cells also are involved. The skeletal response to mechanical signals is a complex process regulated by multiple signaling pathways including that of insulin-like growth factor-1 (IGF-1). Conditional osteocyte deletion of IGF-1 ablates the osteogenic response to mechanical loading. Similarly, osteocyte IGF-1 receptor (IGF-1R) expression is necessary for reloading-induced periosteal bone formation. Transgenic overexpression of IGF-1 in osteoblasts results in enhanced responsiveness to in vivo mechanical loading in mice, a response which is eliminated by osteoblastic conditional disruption of IGF-1 in vivo. Bone marrow derived stem cells (BMSC) from unloaded bone fail to respond to IGF-1 in vitro. IGF-1R is required for the transduction of a mechanical stimulus to downstream effectors, transduction which is lost when the IGF-1R is deleted. Although the molecular mechanisms are not yet fully elucidated, the IGF signaling pathway and its interactions with potentially interlinked signaling cascades involving integrins, the estrogen receptor, and wnt/β-catenin play an important role in regulating adaptive response of cancer bone cells to mechanical stimuli. In this review, we discuss recent advances investigating how IGF-1 and other interlinked molecules and signaling pathways regulate skeletal mechano-transduction involving different bone cells, providing an overview of the IGF-1 signaling mediated cell-specific response to mechanical stimuli. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:576-583, 2018.
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Affiliation(s)
- Faming Tian
- Department of Medicine, Endocrine Research Unit, University of California San Francisco and VA Medical Center, San Francisco,Medical Research Center, North China University of Science and Technology, Tangshan, 063210, P. R. China
| | - Yongmei Wang
- Department of Medicine, Endocrine Research Unit, University of California San Francisco and VA Medical Center, San Francisco
| | - Daniel D. Bikle
- Department of Medicine, Endocrine Research Unit, University of California San Francisco and VA Medical Center, San Francisco,Corresponding author: 1700 Owens St, San Francisco, CA 94158, , Tel: 415-575-0557, FAX: 415-575-0593
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Metzger CE, Brezicha JE, Elizondo JP, Narayanan SA, Hogan HA, Bloomfield SA. Differential responses of mechanosensitive osteocyte proteins in fore- and hindlimbs of hindlimb-unloaded rats. Bone 2017; 105:26-34. [PMID: 28782619 DOI: 10.1016/j.bone.2017.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 07/12/2017] [Accepted: 08/02/2017] [Indexed: 12/28/2022]
Abstract
Osteocytes are believed to be the primary mechanosensors of bone tissue, signaling to osteoblasts and osteoclasts by releasing specific proteins. Sclerostin, interleukin-6 (IL-6), and insulin-like growth factor-I (IGF-I) are osteocyte proteins that signal to osteoblasts. The primary objective of this study was to determine if osteocyte protein response to mechanical unloading is restricted to the unloaded bone using the hindlimb unloading (HU) rodent model. We also examined tumor necrosis factor-α (TNF-α) due to its interactions with all three osteocyte proteins. We hypothesized that unloaded hindlimb cancellous bone would have an altered osteocyte protein (sclerostin, IL-6, and IGF-I) response compared to controls, while the response in the weight-bearing forelimb would not differ from ambulating controls. Male Sprague Dawley rats (7-mo old) experienced either HU (n=7) or normal cage activity (CON; n=7) for 28days. The unloaded distal femur and the weight-bearing proximal humerus were compared in HU vs CON. Metaphyseal bone density was reduced in the HU rats' hindlimb, but not in the proximal humerus, compared to CON values. Osteocyte density was 30% lower in the HU distal femur, but not different from CON in the proximal humerus. %Sclerostin+osteocytes in the distal femur were higher in HU compared to CON, but lower in the proximal humerus. Both %IGF-I+ and %IL-6+ osteocytes were lower in the distal femur for HU, but higher in the proximal humerus for HU. Osterix surface, a marker of osteoblasts, was lower in HU in the distal femur; however, the proximal humerus had more %osterix+surface in HU. In HU %Cathepsin K+ surface, a marker of osteoclasts, was higher in the distal femur and lower in the proximal humerus. %TNF-α+osteocytes were no different from CON in either bone site. HU proximal humerus osteocyte protein responses of sclerostin, IL-6, and IGF-I changed in the opposite direction as observed in the distal femur within the same animal. The opposite response of osteocyte proteins and osteoblast surface in hind- and forelimb bones within the same animal suggests that, while osteocytes in the unloaded hindlimb sense a lack of mechanical strain, osteocytes in the weight-bearing forelimb in HU animals sense some increase in local strain and generate molecular signaling to osteoblasts.
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Affiliation(s)
- Corinne E Metzger
- Department of Health and Kinesiology, Texas A&M University, College Station, TX 77843, United States
| | - Jessica E Brezicha
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, United States
| | - Jon P Elizondo
- Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, United States
| | - S Anand Narayanan
- Department of Medical Physiology, Texas A&M University Health Science Center, Temple, TX 76504, United States
| | - Harry A Hogan
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, United States; Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, United States
| | - Susan A Bloomfield
- Department of Health and Kinesiology, Texas A&M University, College Station, TX 77843, United States.
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Ortinau LC, Linden MA, Dirkes RK, Rector RS, Hinton PS. Exercise initiated after the onset of insulin resistance improves trabecular microarchitecture and cortical bone biomechanics of the tibia in hyperphagic Otsuka Long Evans Tokushima Fatty rats. Bone 2017; 103:188-199. [PMID: 28711659 DOI: 10.1016/j.bone.2017.07.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 06/13/2017] [Accepted: 07/06/2017] [Indexed: 12/25/2022]
Abstract
The present study extends our previous findings that exercise, which prevents the onset of insulin resistance and type 2 diabetes (T2D), also prevents the detrimental effects of T2D on whole-bone and tissue-level strength. Our objective was to determine whether exercise improves bone's structural and material properties if insulin resistance is already present in the Otsuka Long-Evans Tokushima Fatty (OLETF) rat. The OLETF rat is hyperphagic due to a loss-of-function mutation in cholecystokinin-1 receptor (CCK-1 receptor), which leads to progressive obesity, insulin resistance and T2D after the majority of skeletal growth is complete. Because exercise reduces body mass, which is a significant determinant of bone strength, we used a body-mass-matched caloric-restricted control to isolate body-mass-independent effects of exercise on bone. Eight-wk old, male OLETF rats were fed ad libitum until onset of hyperglycemia (20weeks of age), at which time they were randomly assigned to three groups: ad libitum fed, sedentary (O-SED); ad libitum fed, treadmill running (O-EX); or, sedentary, mild caloric restriction to match body mass of O-EX (O-CR). Long-Evans Tokushima Otsuka rats served as the normophagic, normoglycemic controls (L-SED). At 32weeks of age, O-SED rats had T2D as evidenced by hyperglycemia and a significant reduction in fasting insulin compared to OLETFs at 20weeks of age. O-SED rats also had reduced total body bone mineral content (BMC), increased C-terminal telopeptide of type I collagen (CTx)/tartrate resistant acid phosphatase isoform 5b (TRAP5b), decreased N-terminal propeptide of type I procollagen (P1NP), reduced percent cancellous bone volume (BV/TV), trabecular number (Tb.N) and increased trabecular separation (Tb.Sp) and structural model index (SMI) of the proximal tibia compared to L-SED. T2D also adversely affected biomechanical properties of the tibial diaphysis, and serum sclerostin was increased and β-catenin, runt-related transcription factor 2 (Runx2) and insulin-like growth factor-I (IGF-I) protein expression in bone were reduced in O-SED vs. L-SED. O-EX or O-CR had greater total body bone mineral density (BMD) and BMC, and BV/TV, Tb.N, Tb.Sp, and SMI compared to O-SED. O-EX had lower CTx and CR greater P1NP relative to O-SED. O-EX, not O-CR, had greater cortical thickness and area, and improved whole-bone and tissue-level biomechanical properties associated with a 4-fold increase in cortical bone β-catenin protein expression vs. O-SED. In summary, EX or CR initiated after the onset of insulin resistance preserved cancellous bone volume and structure, and EX elicited additional benefits in cortical bone.
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Affiliation(s)
- Laura C Ortinau
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States
| | - Melissa A Linden
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States; Research Service-Harry S. Truman Memorial Veterans Medical Center, Columbia, MO, United States
| | - Rebecca K Dirkes
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States
| | - R Scott Rector
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States; Department of Medicine, Gastroenterology and Hepatology, University of Missouri, Columbia, MO, United States; Research Service-Harry S. Truman Memorial Veterans Medical Center, Columbia, MO, United States
| | - Pamela S Hinton
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States.
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Abstract
PURPOSE OF REVIEW Over the past decades, osteocytes have emerged as mechano-sensors of bone and master regulators of bone homeostasis. This article summarizes latest research and progress made in understanding osteocyte mechanobiology and critically reviews tools currently available to study these cells. RECENT FINDINGS Whereas increased mechanical forces promote bone formation, decrease loading is always associated with bone loss and skeletal fragility. Recent studies identified cilia, integrins, calcium channels, and G-protein coupled receptors as important sensors of mechanical forces and Ca2+ and cAMP signaling as key effectors. Among transcripts regulated by mechanical forces, sclerostin and RANKL have emerged as potential therapeutic targets for disuse-induced bone loss. In this paper, we review the mechanisms by which osteocytes perceive and transduce mechanical cues and the models available to study mechano-transduction. Future directions of the field are also discussed.
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Affiliation(s)
- Yuhei Uda
- Molecular and Cell Biology, Boston University Henry M. Goldman School of Dental Medicine, Boston, MA, USA
| | - Ehab Azab
- Molecular and Cell Biology, Boston University Henry M. Goldman School of Dental Medicine, Boston, MA, USA
| | - Ningyuan Sun
- Molecular and Cell Biology, Boston University Henry M. Goldman School of Dental Medicine, Boston, MA, USA
| | - Chao Shi
- Molecular and Cell Biology, Boston University Henry M. Goldman School of Dental Medicine, Boston, MA, USA
- Department of Orthopaedics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China
| | - Paola Divieti Pajevic
- Molecular and Cell Biology, Boston University Henry M. Goldman School of Dental Medicine, Boston, MA, USA.
- , 700 Albany Street, W201C, Boston, MA, 02118, USA.
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Ortinau LC, Linden MA, Rector RS, Hinton PS. Exercise improves femoral whole-bone and tissue-level biomechanical properties in hyperphagic OLETF rats. Appl Physiol Nutr Metab 2017; 42:884-892. [PMID: 28460190 DOI: 10.1139/apnm-2017-0077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
An often-overlooked comorbidity of type 2 diabetes (T2D) is increased fracture risk. Since traditional T2D therapies focus solely on glucose homeostasis, there is an increased need for effective treatment strategies that improve both metabolic and bone health. The current study evaluated if previously reported protective effects of exercise (EX) on cortical bone geometry and biomechanical properties are due to the prevention of obesity compared with obese Otsuka Long-Evans Tokushima Fatty (OLETF) rats or the unique skeletal effects of exercise. Four-week-old male OLETF rats were randomly assigned to 1 of 3 groups, each fed a standard rodent chow diet until 40 weeks of age: ad libitum-fed sedentary (O-SED), ad libitum-fed EX (O-EX), or a control group body-weight-matched to the O-EX group by caloric restriction (O-CR). Ad libitum-fed sedentary Long-Evans Tokushima Otsuka (L-SED) rats were used as a lean control. EX or CR prevented the excess body mass accumulation and elevated HbA1c observed in O-SED. Total-body bone mineral density was greater in O-EX than O-CR, but similar to L-SED and O-SED. O-EX and O-CR had lower osteocalcin and TRAP5b than O-SED and L-SED. EX or CR prevented the ∼3-fold increase in CTx in O-SED versus L-SED. EX increased femoral cortical mass accumulation and expansion at the mid-diaphysis compared with O-CR. EX or CR significantly increased tissue-level stiffness and strength compared with O-SED and L-SED, but O-EX had greater whole-bone stiffness than all other groups. In summary, EX has distinct advantages over CR for improving bone biomechanical properties in hyperphagic OLETF rats.
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Affiliation(s)
- Laura C Ortinau
- a Department of Nutrition and Exercise Physiology, University of Missouri-Columbia, 204 Gwynn Hall, Columbia, MO 65211, USA
| | - Melissa A Linden
- a Department of Nutrition and Exercise Physiology, University of Missouri-Columbia, 204 Gwynn Hall, Columbia, MO 65211, USA.,b Research Service-Harry S. Truman Memorial Veterans Medical Center, Columbia, MO, USA
| | - R Scott Rector
- a Department of Nutrition and Exercise Physiology, University of Missouri-Columbia, 204 Gwynn Hall, Columbia, MO 65211, USA.,b Research Service-Harry S. Truman Memorial Veterans Medical Center, Columbia, MO, USA.,c Department of Medicine, Gastroenterology and Hepatology, University of Missouri, Columbia, MO, USA
| | - Pamela S Hinton
- a Department of Nutrition and Exercise Physiology, University of Missouri-Columbia, 204 Gwynn Hall, Columbia, MO 65211, USA
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Metzger CE, Narayanan A, Zawieja DC, Bloomfield SA. Inflammatory Bowel Disease in a Rodent Model Alters Osteocyte Protein Levels Controlling Bone Turnover. J Bone Miner Res 2017; 32:802-813. [PMID: 27796050 DOI: 10.1002/jbmr.3027] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/26/2016] [Accepted: 10/28/2016] [Indexed: 12/30/2022]
Abstract
Bone loss is a common comorbidity of inflammatory bowel disease (IBD), leading to elevated fracture risk in these patients. Inflammatory factors associated with IBD cause increased bone resorption and decreased bone formation with multiple factors implicated as instigators of these alterations. In this project, we examined the influence of IBD on osteocyte proteins in male rats (2 months old) divided into two groups: induced gut inflammation via 2,4,6-trinitrobenzenesulfonic acid (TNBS) enema, and vehicle control. We examined the prevalence of two pro-inflammatory cytokines, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), an anti-inflammatory cytokine, interleukin-10 (IL-10), the anabolic factor insulin-like growth factor-I (IGF-I), osteoclastogenesis regulators RANKL and OPG, and the bone formation inhibitor sclerostin in osteocytes in three bone compartments 4 weeks after initiation of gut inflammation. Histomorphometry of the proximal tibia and fourth lumbar vertebra revealed lower bone volume, lower bone formation rate (BFR), lower osteoid surface (OS), and higher osteoclast surface (Oc.S) with TNBS. Tibial mid-shaft periosteal BFR was also lower with TNBS. Immunohistochemical staining of the distal femur demonstrated that %TNF-α+ , %IL-6+ , %RANKL+ , and %OPG+ osteocytes were elevated in cancellous bone in TNBS animals compared to vehicle. These changes were coincident with increased bone resorption. With regression analysis, %RANKL+ osteocytes statistically predicted the increase in cancellous Oc.S (R2 = 0.565). Increased %sclerostin+ osteocytes observed in the TNBS treatment predicted declines in cancellous OS (R2 = 0.581) as well as BFR in cancellous and cortical bone (R2 = 0.674, R2 = 0.908, respectively). Contrary to our hypothesis, %IGF-I+ osteocytes increased in TNBS animals. In conclusion, the IBD model produced a systemic inflammation that altered the regulatory protein profile in osteocytes that control bone resorption and bone formation, likely contributing to IBD-induced bone loss. These data highlight a potential mechanistic role of osteocytes in inflammatory bone loss associated with IBD and systemic inflammation. © 2017 American Society for Bone and Mineral Research.
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Affiliation(s)
- Corinne E Metzger
- Department of Health and Kinesiology, Texas A&M University Health Science Center, College Station, TX, USA
| | - Anand Narayanan
- Department of Medical Physiology, College of Medicine, Texas A&M University, College Station, TX, USA
| | - David C Zawieja
- Department of Medical Physiology, College of Medicine, Texas A&M University, College Station, TX, USA
| | - Susan A Bloomfield
- Department of Health and Kinesiology, Texas A&M University Health Science Center, College Station, TX, USA.,Graduate Faculty of Nutrition, Texas A&M University, College Station, TX, USA
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Galea GL, Lanyon LE, Price JS. Sclerostin's role in bone's adaptive response to mechanical loading. Bone 2017; 96:38-44. [PMID: 27742499 PMCID: PMC5340132 DOI: 10.1016/j.bone.2016.10.008] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/27/2016] [Accepted: 10/10/2016] [Indexed: 01/08/2023]
Abstract
Mechanical loading is the primary functional determinant of bone mass and architecture, and osteocytes play a key role in translating mechanical signals into (re)modelling responses. Although the precise mechanisms remain unclear, Wnt signalling pathway components, and the anti-osteogenic canonical Wnt inhibitor Sost/sclerostin in particular, play an important role in regulating bone's adaptive response to loading. Increases in loading-engendered strains down-regulate osteocyte sclerostin expression, whereas reduced strains, as in disuse, are associated with increased sclerostin production and bone loss. However, while sclerostin up-regulation appears to be necessary for the loss of bone with disuse, the role of sclerostin in the osteogenic response to loading is more complex. While mice unable to down-regulate sclerostin do not gain bone with loading, Sost knockout mice have an enhanced osteogenic response to loading. The molecular mechanisms by which osteocytes sense and transduce loading-related stimuli into changes in sclerostin expression remain unclear but include several, potentially interlinked, signalling cascades involving periostin/integrin, prostaglandin, estrogen receptor, calcium/NO and Igf signalling. Deciphering the mechanisms by which changes in the mechanical environment regulate sclerostin production may lead to the development of therapeutic strategies that can reverse the skeletal structural deterioration characteristic of disuse and age-related osteoporosis and enhance bones' functional adaptation to loading. By enhancing the osteogenic potential of the context in which individual therapies such as sclerostin antibodies act it may become possible to both prevent and reverse the age-related skeletal structural deterioration characteristic of osteoporosis.
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Affiliation(s)
- Gabriel L Galea
- Newlife Birth Defects Research Centre, Institute of Child Health, University College London, London WC1N 1EH, United Kingdom; School of Veterinary Sciences, University of Bristol, Langford House, Langford, Bristol BS40 5DU, United Kingdom.
| | - Lance E Lanyon
- School of Veterinary Sciences, University of Bristol, Langford House, Langford, Bristol BS40 5DU, United Kingdom
| | - Joanna S Price
- School of Veterinary Sciences, University of Bristol, Langford House, Langford, Bristol BS40 5DU, United Kingdom
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Hinton PS, Nigh P, Thyfault J. Serum sclerostin decreases following 12months of resistance- or jump-training in men with low bone mass. Bone 2017; 96:85-90. [PMID: 27744012 PMCID: PMC5328803 DOI: 10.1016/j.bone.2016.10.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 09/07/2016] [Accepted: 10/10/2016] [Indexed: 12/17/2022]
Abstract
PURPOSE We previously reported that 12months of resistance training (RT, 2×/wk, N=19) or jump training (JUMP, 3×/wk, N=19) increased whole body and lumbar spine BMD and increased serum bone formation markers relative to resorption in physically active (≥4h/wk) men (mean age: 44±2y; median: 44y) with osteopenia of the hip or spine. The purpose of this secondary analysis was to examine the effects of the RT or JUMP intervention on potential endocrine mediators of the exercise effects on bone, specifically IGF-I, PTH and sclerostin. METHODS Fasting blood samples were collected after a 24-h period of no exercise at baseline and after 12months of RT or JUMP. IGF-I, PTH and sclerostin were measured in serum by ELISA. The effects of RT or JUMP on IGF-I, PTH and sclerostin were evaluated using 2×2 repeated measures ANOVA (time, group). This study was conducted in accordance with the Declaration of Helsinki and was approved by the University of Missouri IRB. RESULTS Sclerostin concentrations in serum significantly decreased and IGF-I significantly increased after 12months of RT or JUMP; while PTH remained unchanged. CONCLUSION The beneficial effects of long-term, progressive-intensity RT or JUMP on BMD in moderately active men with low bone mass are associated with decreased sclerostin and increased IGF-I.
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Affiliation(s)
- Pamela S Hinton
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211, United States.
| | - Peggy Nigh
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211, United States
| | - John Thyfault
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211, United States; Internal Medicine - Division of GI and Hepatology, University of Missouri, Columbia, MO 65211, United States
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Lau KHW, Rundle CH, Zhou XD, Baylink DJ, Sheng MHC. Conditional deletion of IGF-I in osteocytes unexpectedly accelerates bony union of the fracture gap in mice. Bone 2016; 92:18-28. [PMID: 27519969 DOI: 10.1016/j.bone.2016.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 08/03/2016] [Accepted: 08/08/2016] [Indexed: 01/14/2023]
Abstract
This study evaluated the effects of deficient IGF-I expression in osteocytes on fracture healing. Transgenic mice with conditional knockout (cKO) of Igf1 in osteocytes were generated by crossing Dmp1-Cre mice with Igf1 flox mice. Fractures were created on the mid-shaft of tibia of 12-week-old male cKO mice and wild-type (WT) littermates by three-point bending. At 21 and 28days post-fracture healing, the increases in cortical bone mineral density, mineral content, bone area, and thickness, as well as sub-cortical bone mineral content at the fracture site were each greater in cKO calluses than in WT calluses. There were 85% decrease in the cartilage area and >2-fold increase in the number of osteoclasts in cKO calluses at 14days post-fracture, suggesting a more rapid remodeling of endochondral bone. The upregulation of mRNA levels of osteoblast marker genes (cbfa1, alp, Opn, and Ocn) was greater in cKO calluses than in WT calluses. μ-CT analysis suggested an accelerated bony union of the fracture gap in cKO mice. The Sost mRNA level was reduced by 50% and the Bmp2 mRNA level was increased 3-fold in cKO fractures at 14days post-fracture, but the levels of these two mRNAs in WT fractures were unchanged, suggesting that the accelerated fracture repair may in part act through the Wnt and/or BMP signaling. In conclusion, conditional deletion of Igf1 in osteocytes not only did not impair, but unexpectedly enhanced, bony union of the fracture gap. The accelerated bony union was due in part to upregulation of the Wnt and BMP2 signaling in response to deficient osteocyte-derived IGF-I expression, which in turn favors intramembranous over endochondral bone repair.
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Affiliation(s)
- Kin-Hing W Lau
- Division of Regenerative Medicine, Department of Medicine, Loma Linda University School of Medicine, Loma Linda, CA, USA; Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, CA, USA
| | - Charles H Rundle
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, CA, USA
| | - Xiao-Dong Zhou
- Division of Regenerative Medicine, Department of Medicine, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - David J Baylink
- Division of Regenerative Medicine, Department of Medicine, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Matilda H-C Sheng
- Division of Regenerative Medicine, Department of Medicine, Loma Linda University School of Medicine, Loma Linda, CA, USA.
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Lindsey RC, Mohan S. Skeletal effects of growth hormone and insulin-like growth factor-I therapy. Mol Cell Endocrinol 2016; 432:44-55. [PMID: 26408965 PMCID: PMC4808510 DOI: 10.1016/j.mce.2015.09.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 09/21/2015] [Accepted: 09/22/2015] [Indexed: 10/23/2022]
Abstract
The growth hormone/insulin-like growth factor (GH/IGF) axis is critically important for the regulation of bone formation, and deficiencies in this system have been shown to contribute to the development of osteoporosis and other diseases of low bone mass. The GH/IGF axis is regulated by a complex set of hormonal and local factors which can act to regulate this system at the level of the ligands, receptors, IGF binding proteins (IGFBPs), or IGFBP proteases. A combination of in vitro studies, transgenic animal models, and clinical human investigations has provided ample evidence of the importance of the endocrine and local actions of both GH and IGF-I, the two major components of the GH/IGF axis, in skeletal growth and maintenance. GH- and IGF-based therapies provide a useful avenue of approach for the prevention and treatment of diseases such as osteoporosis.
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Affiliation(s)
- Richard C Lindsey
- Musculoskeletal Disease Center, Loma Linda VA Healthcare System, Loma Linda, CA 92357, USA; Department of Medicine, Loma Linda University, Loma Linda, CA 92354, USA; Department of Biochemistry, Loma Linda University, Loma Linda, CA 92354, USA
| | - Subburaman Mohan
- Musculoskeletal Disease Center, Loma Linda VA Healthcare System, Loma Linda, CA 92357, USA; Department of Medicine, Loma Linda University, Loma Linda, CA 92354, USA; Department of Biochemistry, Loma Linda University, Loma Linda, CA 92354, USA.
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Laurent MR, Dubois V, Claessens F, Verschueren SMP, Vanderschueren D, Gielen E, Jardí F. Muscle-bone interactions: From experimental models to the clinic? A critical update. Mol Cell Endocrinol 2016; 432:14-36. [PMID: 26506009 DOI: 10.1016/j.mce.2015.10.017] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/13/2015] [Accepted: 10/20/2015] [Indexed: 02/06/2023]
Abstract
Bone is a biomechanical tissue shaped by forces from muscles and gravitation. Simultaneous bone and muscle decay and dysfunction (osteosarcopenia or sarco-osteoporosis) is seen in ageing, numerous clinical situations including after stroke or paralysis, in neuromuscular dystrophies, glucocorticoid excess, or in association with vitamin D, growth hormone/insulin like growth factor or sex steroid deficiency, as well as in spaceflight. Physical exercise may be beneficial in these situations, but further work is still needed to translate acceptable and effective biomechanical interventions like vibration therapy from animal models to humans. Novel antiresorptive and anabolic therapies are emerging for osteoporosis as well as drugs for sarcopenia, cancer cachexia or muscle wasting disorders, including antibodies against myostatin or activin receptor type IIA and IIB (e.g. bimagrumab). Ideally, increasing muscle mass would increase muscle strength and restore bone loss from disuse. However, the classical view that muscle is unidirectionally dominant over bone via mechanical loading is overly simplistic. Indeed, recent studies indicate a role for neuronal regulation of not only muscle but also bone metabolism, bone signaling pathways like receptor activator of nuclear factor kappa-B ligand (RANKL) implicated in muscle biology, myokines affecting bone and possible bone-to-muscle communication. Moreover, pharmacological strategies inducing isolated myocyte hypertrophy may not translate into increased muscle power because tendons, connective tissue, neurons and energy metabolism need to adapt as well. We aim here to critically review key musculoskeletal molecular pathways involved in mechanoregulation and their effect on the bone-muscle unit as a whole, as well as preclinical and emerging clinical evidence regarding the effects of sarcopenia therapies on osteoporosis and vice versa.
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Affiliation(s)
- Michaël R Laurent
- Gerontology and Geriatrics, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Centre for Metabolic Bone Diseases, University Hospitals Leuven, 3000 Leuven, Belgium.
| | - Vanessa Dubois
- Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Frank Claessens
- Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Sabine M P Verschueren
- Research Group for Musculoskeletal Rehabilitation, Department of Rehabilitation Science, KU Leuven, 3000 Leuven, Belgium
| | - Dirk Vanderschueren
- Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Evelien Gielen
- Gerontology and Geriatrics, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Centre for Metabolic Bone Diseases, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Ferran Jardí
- Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
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Hughes JM, Popp KL, Yanovich R, Bouxsein ML, Matheny RW. The role of adaptive bone formation in the etiology of stress fracture. Exp Biol Med (Maywood) 2016; 242:897-906. [PMID: 27496801 DOI: 10.1177/1535370216661646] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Stress fractures are common injuries with load-bearing activities. Stress fractures have been reported in the scientific literature for over a century; however, the etiology continues to be investigated with important distinctions made between the contributions of the tissue-level processes of bone remodeling and modeling. In response to novel repetitive loading, increased bone remodeling may serve to replace fatigue-damaged bone while at the same time creating temporary porosity. Much attention has been given to the role of remodeling in the etiology of stress fracture; however, the role of bone modeling has received less attention. Modest increases in modeling, via bone formation on the periosteal surface of long bones in response to mechanical loading, greatly increases the fatigue resistance of bone. Thus, enhancing this adaptive bone formation is a promising target for stress fracture prevention, and a focus on adaptive bone formation may reveal novel risk factors for stress fracture.
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Affiliation(s)
- Julie M Hughes
- 1 Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, MA 01760, USA
| | - Kristin L Popp
- 2 Endocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Ran Yanovich
- 3 The Warrior Health Research Institute of Military Physiology, Israel Defense Forces' Medical Corps.,4 Heller Institute of Medical Research, Sheba Medical Center, Tel-Hashomer 52621, Israel
| | - Mary L Bouxsein
- 2 Endocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA.,5 Center for Advanced Orthopedic Studies, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.,6 Department of Orthopaedic Surgery, Harvard Medical School, Boston, MA 02215, USA
| | - Ronald W Matheny
- 1 Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, MA 01760, USA
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44
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Abstract
Skeletal muscle and bone rely on a number of growth factors to undergo development, modulate growth, and maintain physiological strength. A major player in these actions is insulin-like growth factor I (IGF-I). However, because this growth factor can directly enhance muscle mass and bone density, it alters the state of the musculoskeletal system indirectly through mechanical crosstalk between these two organ systems. Thus, there are clearly synergistic actions of IGF-I that extend beyond the direct activity through its receptor. This review will cover the production and signaling of IGF-I as it pertains to muscle and bone, the chemical and mechanical influences that arise from IGF-I activity, and the potential for therapeutic strategies based on IGF-I. This article is part of a Special Issue entitled "Muscle Bone Interactions".
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45
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Svensson J, Windahl SH, Saxon L, Sjögren K, Koskela A, Tuukkanen J, Ohlsson C. Liver-derived IGF-I regulates cortical bone mass but is dispensable for the osteogenic response to mechanical loading in female mice. Am J Physiol Endocrinol Metab 2016; 311:E138-44. [PMID: 27221117 DOI: 10.1152/ajpendo.00107.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/17/2016] [Indexed: 01/29/2023]
Abstract
Low circulating IGF-I is associated with increased fracture risk. Conditional depletion of IGF-I produced in osteoblasts or osteocytes inhibits the bone anabolic effect of mechanical loading. Here, we determined the role of endocrine IGF-I for the osteogenic response to mechanical loading in young adult and old female mice with adult, liver-specific IGF-I inactivation (LI-IGF-I(-/-) mice, serum IGF-I reduced by ≈70%) and control mice. The right tibia was subjected to short periods of axial cyclic compressive loading three times/wk for 2 wk, and measurements were performed using microcomputed tomography and mechanical testing by three-point bending. In the nonloaded left tibia, the LI-IGF-I(-/-) mice had lower cortical bone area and increased cortical porosity, resulting in reduced bone mechanical strength compared with the controls. Mechanical loading induced a similar response in LI-IGF-I(-/-) and control mice in terms of cortical bone area and trabecular bone volume fraction. In fact, mechanical loading produced a more marked increase in cortical bone mechanical strength, which was associated with a less marked increase in cortical porosity, in the LI-IGF-I(-/-) mice compared with the control mice. In conclusion, liver-derived IGF-I regulates cortical bone mass, cortical porosity, and mechanical strength under normal (nonloaded) conditions. However, despite an ∼70% reduction in circulating IGF-I, the osteogenic response to mechanical loading was not attenuated in the LI-IGF-I(-/-) mice.
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Affiliation(s)
- Johan Svensson
- Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden;
| | - Sara H Windahl
- Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; School of Veterinary Sciences, Bristol United Kingdom
| | - Leanne Saxon
- The Royal Veterinary College, London United Kingdom; and
| | - Klara Sjögren
- Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Antti Koskela
- Department of Anatomy and Cell Biology, Institute of Cancer Research and Translational Medicine, Medical Research Center, University of Oulu, Oulu, Finland
| | - Juha Tuukkanen
- Department of Anatomy and Cell Biology, Institute of Cancer Research and Translational Medicine, Medical Research Center, University of Oulu, Oulu, Finland
| | - Claes Ohlsson
- Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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46
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Polyzos SA, Anastasilakis AD, Kountouras J, Makras P, Papatheodorou A, Kokkoris P, Sakellariou GT, Terpos E. Circulating sclerostin and Dickkopf-1 levels in patients with nonalcoholic fatty liver disease. J Bone Miner Metab 2016; 34:447-56. [PMID: 26056025 DOI: 10.1007/s00774-015-0687-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 05/09/2015] [Indexed: 12/12/2022]
Abstract
There is increasing evidence for bone-liver interplay. The main aim of this study was to determine serum sclerostin and Dickkopf (DKK)-1 levels in patients with nonalcoholic fatty liver disease (NAFLD) and their association with the disease severity. Patients with biopsy-proven NAFLD, 13 with nonalcoholic simple steatosis (SS) and 14 with steatohepatitis (NASH), and 20 gender-, age-, body mass index- and waist circumference-matched controls were enrolled. Serum sclerostin, DKK-1, bone turnover markers, vitamin D, insulin and standard biochemical and hematologic parameters were measured; lumbar spinal dual-energy X-ray absorptiometry was performed. We observed that there was a progressive decline in serum sclerostin levels from the controls (76.1 ± 6.8) to SS (53.5 ± 6.4) and NASH (46.0 ± 8.1 pmol/l) patients (p = 0.009); in adjusted pairwise comparisons, sclerostin was significantly higher in the controls than in NASH patients (p = 0.012). Although serum DKK-1 did not differ between groups (p = 0.135), there was a trend toward U-shaped distribution (controls 35.8 ± 2.8; SS 27.3 ± 2.9; NASH 36.8 ± 4.4 pmol/l). Higher DKK-1 levels were independently associated with NASH. Regarding specific histological lesions, DKK-1 levels were marginally lower in NAFLD patients with lower (≤33 %) than higher (>33 %) steatosis grade (27.7 ± 3.1 and 38.8 ± 4.7 pmol/l, respectively; p = 0.049). No other significant difference was observed within histological lesions. In conclusion, serum sclerostin levels were lower in NASH patients than in controls. DKK-1 levels were independently associated with NASH in NAFLD patients. The potential importance of these findings indicates a possible bone-liver interaction and warrants further investigation.
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Affiliation(s)
- Stergios A Polyzos
- Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, 13 Simou Lianidi, 551 34, Thessaloniki, Macedonia, Greece.
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | | | - Jannis Kountouras
- Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, 13 Simou Lianidi, 551 34, Thessaloniki, Macedonia, Greece
| | - Polyzois Makras
- Department of Endocrinology and Diabetes, 251 Hellenic Air Force and VA General Hospital, Athens, Greece
| | | | - Panagiotis Kokkoris
- Department of Medical Research, 251 Hellenic Air Force and VA General Hospital, Athens, Greece
| | | | - Evangelos Terpos
- Department of Clinical Therapeutics, University of Athens School of Medicine, Athens, Greece
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47
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Gao X, Usas A, Lu A, Kozemchak A, Tang Y, Poddar M, Sun X, Cummins JH, Huard J. Cyclooxygenase-2 deficiency impairs muscle-derived stem cell-mediated bone regeneration via cellular autonomous and non-autonomous mechanisms. Hum Mol Genet 2016; 25:3216-3231. [PMID: 27354351 DOI: 10.1093/hmg/ddw172] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 04/26/2016] [Accepted: 05/31/2016] [Indexed: 01/10/2023] Open
Abstract
This study investigated the role of cyclooxygenase-2 (COX-2) expression by donor and host cells in muscle-derived stem cell (MDSC)-mediated bone regeneration utilizing a critical size calvarial defect model. We found that BMP4/green fluorescent protein (GFP)-transduced MDSCs formed significantly less bone in COX-2 knock-out (Cox-2KO) than in COX-2 wild-type (WT) mice. BMP4/GFP-transduced Cox-2KO MDSCs also formed significantly less bone than transduced WT MDSCs when transplanted into calvarial defects created in CD-1 nude mice. The impaired bone regeneration in the Cox-2KO MDSCBMP4/GFP group is associated with downregulation of BMP4-pSMAD1/5 signaling, decreased osteogenic differentiation and lowered proliferation capacity after transplantation, compared with WT MDSCBMP4/GFP cells. The Cox-2KO MDSCBMP4/GFP group demonstrated a reduction in cell survival and direct osteogenic differentiation in vitro These effects were mediated in part by the downregulation of Igf1 and Igf2. In addition, the Cox-2KO MDSCBMP4/GFP cells recruited fewer macrophages than the WT MDSC/BMP4/GFP cells in the early phase after injury. We concluded that the bone regeneration capacity of Cox-2KO MDSCs was impaired because of a reduction in cell proliferation and survival capacities, reduction in osteogenic differentiation and a decrease in the ability of the cells to recruit host cells to the injury site.
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Affiliation(s)
- Xueqin Gao
- Stem Cell Research Center, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Orthopaedic Surgery, Brown Institute for Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA.,Center for Regenerative Sports Medicine, Steadman Philippon Research Institute, Vail, CO, USA and
| | - Arvydas Usas
- Stem Cell Research Center, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.,Institute of Physiology and Pharmacology, Lithuanian University of Health Sciences, Medical Academy, Kaunas, Lithuania
| | - Aiping Lu
- Stem Cell Research Center, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Orthopaedic Surgery, Brown Institute for Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA.,Center for Regenerative Sports Medicine, Steadman Philippon Research Institute, Vail, CO, USA and
| | - Adam Kozemchak
- Stem Cell Research Center, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ying Tang
- Stem Cell Research Center, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Minakshi Poddar
- Stem Cell Research Center, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Xuying Sun
- Department of Orthopaedic Surgery, Brown Institute for Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - James H Cummins
- Stem Cell Research Center, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Orthopaedic Surgery, Brown Institute for Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA.,Center for Regenerative Sports Medicine, Steadman Philippon Research Institute, Vail, CO, USA and
| | - Johnny Huard
- Stem Cell Research Center, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA .,Department of Orthopaedic Surgery, Brown Institute for Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA.,Center for Regenerative Sports Medicine, Steadman Philippon Research Institute, Vail, CO, USA and
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48
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Yakar S, Isaksson O. Regulation of skeletal growth and mineral acquisition by the GH/IGF-1 axis: Lessons from mouse models. Growth Horm IGF Res 2016; 28:26-42. [PMID: 26432542 PMCID: PMC4809789 DOI: 10.1016/j.ghir.2015.09.004] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 09/16/2015] [Accepted: 09/24/2015] [Indexed: 12/31/2022]
Abstract
The growth hormone (GH) and its downstream mediator, the insulin-like growth factor-1 (IGF-1), construct a pleotropic axis affecting growth, metabolism, and organ function. Serum levels of GH/IGF-1 rise during pubertal growth and associate with peak bone acquisition, while during aging their levels decline and associate with bone loss. The GH/IGF-1 axis was extensively studied in numerous biological systems including rodent models and cell cultures. Both hormones act in an endocrine and autocrine/paracrine fashion and understanding their distinct and overlapping contributions to skeletal acquisition is still a matter of debate. GH and IGF-1 exert their effects on osteogenic cells via binding to their cognate receptor, leading to activation of an array of genes that mediate cellular differentiation and function. Both hormones interact with other skeletal regulators, such as sex-steroids, thyroid hormone, and parathyroid hormone, to facilitate skeletal growth and metabolism. In this review we summarized several rodent models of the GH/IGF-1 axis and described key experiments that shed new light on the regulation of skeletal growth by the GH/IGF-1 axis.
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Affiliation(s)
- Shoshana Yakar
- David B. Kriser Dental Center, Department of Basic Science and Craniofacial Biology New York University College of Dentistry New York, NY 10010-408
| | - Olle Isaksson
- Institute of Medicine, Sahlgrenska University Hospital, University of Gothenburg, SE-41345 Gothenburg, Sweden
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49
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Abstract
Mechanical loading is a potent anabolic regulator of bone mass, and the first line of defense for bone loss is weight-bearing exercise. Likewise, protected weight bearing is the first prescribed physical therapy following orthopedic reconstructive surgery. In both cases, enhancement of new bone formation is the goal. Our understanding of the physical cues, mechanisms of force sensation, and the subsequent cellular response will help identify novel physical and therapeutic treatments for age- and disuse-related bone loss, delayed- and nonunion fractures, and significant bony defects. This review highlights important new insights into the principles and mechanisms governing mechanical adaptation of the skeleton during homeostasis and repair and ends with a summary of clinical implications stemming from our current understanding of how bone adapts to biophysical force.
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50
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Bikle DD, Tahimic C, Chang W, Wang Y, Philippou A, Barton ER. Role of IGF-I signaling in muscle bone interactions. Bone 2015; 80:79-88. [PMID: 26453498 PMCID: PMC4600536 DOI: 10.1016/j.bone.2015.04.036] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 04/11/2015] [Accepted: 04/22/2015] [Indexed: 12/16/2022]
Abstract
Skeletal muscle and bone rely on a number of growth factors to undergo development, modulate growth, and maintain physiological strength. A major player in these actions is insulin-like growth factor I (IGF-I). However, because this growth factor can directly enhance muscle mass and bone density, it alters the state of the musculoskeletal system indirectly through mechanical crosstalk between these two organ systems. Thus, there are clearly synergistic actions of IGF-I that extend beyond the direct activity through its receptor. This review will cover the production and signaling of IGF-I as it pertains to muscle and bone, the chemical and mechanical influences that arise from IGF-I activity, and the potential for therapeutic strategies based on IGF-I. This article is part of a Special Issue entitled "Muscle Bone Interactions".
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Affiliation(s)
- Daniel D Bikle
- VA Medical Center and University of California San Francisco, San Francisco, CA, USA
| | - Candice Tahimic
- VA Medical Center and University of California San Francisco, San Francisco, CA, USA
| | - Wenhan Chang
- VA Medical Center and University of California San Francisco, San Francisco, CA, USA
| | - Yongmei Wang
- VA Medical Center and University of California San Francisco, San Francisco, CA, USA
| | - Anastassios Philippou
- National and Kapodistrian University of Athens, Department of Physiology, Medical School, Goudi-Athens, Greece
| | - Elisabeth R Barton
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA.
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