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Luo Y, Zheng S, Xiao W, Zhang H, Li Y. Pannexins in the musculoskeletal system: new targets for development and disease progression. Bone Res 2024; 12:26. [PMID: 38705887 PMCID: PMC11070431 DOI: 10.1038/s41413-024-00334-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 03/04/2024] [Accepted: 04/01/2024] [Indexed: 05/07/2024] Open
Abstract
During cell differentiation, growth, and development, cells can respond to extracellular stimuli through communication channels. Pannexin (Panx) family and connexin (Cx) family are two important types of channel-forming proteins. Panx family contains three members (Panx1-3) and is expressed widely in bone, cartilage and muscle. Although there is no sequence homology between Panx family and Cx family, they exhibit similar configurations and functions. Similar to Cxs, the key roles of Panxs in the maintenance of physiological functions of the musculoskeletal system and disease progression were gradually revealed later. Here, we seek to elucidate the structure of Panxs and their roles in regulating processes such as osteogenesis, chondrogenesis, and muscle growth. We also focus on the comparison between Cx and Panx. As a new key target, Panxs expression imbalance and dysfunction in muscle and the therapeutic potentials of Panxs in joint diseases are also discussed.
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Affiliation(s)
- Yan Luo
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- Department of Clinical Medicine, Xiangya Medicine School, Central South University, Changsha, Hunan, 410008, China
| | - Shengyuan Zheng
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- Department of Clinical Medicine, Xiangya Medicine School, Central South University, Changsha, Hunan, 410008, China
| | - Wenfeng Xiao
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Hang Zhang
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.
| | - Yusheng Li
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China.
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2
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Ma L, Wang W, Xu G, Li H, Liu F, Shao H, Zhang X, Ma Y, Li G, Li H, Gao S, Ling P. Connexin 43 in the function and homeostasis of osteocytes: a narrative review. ANNALS OF JOINT 2023; 9:10. [PMID: 38529291 PMCID: PMC10929443 DOI: 10.21037/aoj-23-65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 11/29/2023] [Indexed: 03/27/2024]
Abstract
Background and Objective Connexin 43 (Cx43) is the main gap junction (GJ) protein and hemichannel protein in bone tissue. It is involved in the formation of hemichannels and GJs and establishes channels that can communicate directly to exchange substances and signals, affecting the structure and function of osteocytes. CX43 is very important for the normal development of bone tissue and the establishment and balance of bone reconstruction. However, the molecular mechanisms by which CX43 regulates osteoblast function and homeostasis have been less well studied, and this article provides a review of research in this area. Methods We searched the PubMed, EMBASE, Cochrane Library, and Web of Science databases for studies published up to June 2023 using the keywords Connexin 43/Cx43 and Osteocytes. Screening of literatures according to inclusion and exclusion guidelines and summarized the results. Key Content and Findings Osteocytes, osteoblasts, and osteoclasts all express Cx43 and form an overall network through the interaction between GJs. Cx43 is not only involved in the mechanical response of bone tissue but also in the regulation of signal transduction, which could provide new molecular markers and novel targets for the treatment of certain bone diseases. Conclusions Cx43 is expressed in osteoblasts, osteoclasts, and osteoclasts and plays an important role in regulating the function, signal transduction, and mechanotransduction of osteocytes. This review offers a new contribution to the literature by summarizing the relationship between Cx43, a key protein of bone tissue, and osteoblasts.
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Affiliation(s)
- Liang Ma
- Department of Orthopedics, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
- Post-doctoral Station of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Wenzhao Wang
- Department of Orthopedics, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Guixuan Xu
- Department of Pathology and Medical Research Center, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Hao Li
- Department of Joint Surgery, Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Fei Liu
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
| | - Huarong Shao
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
| | - Xiuhua Zhang
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
| | - Yuxia Ma
- Post-doctoral Station of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Gang Li
- Department of Orthopedics, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Hui Li
- Department of Operating Room, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Shuzhong Gao
- Post-doctoral Station of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Peixue Ling
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
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Feher B, Kampleitner C, Heimel P, Tangl S, Helms JA, Kuchler U, Gruber R. The effect of osteocyte-derived RANKL on bone graft remodeling: An in vivo experimental study. Clin Oral Implants Res 2023; 34:1417-1427. [PMID: 37792417 DOI: 10.1111/clr.14187] [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: 06/10/2023] [Revised: 09/11/2023] [Accepted: 09/17/2023] [Indexed: 10/05/2023]
Abstract
OBJECTIVES Autologous bone is considered the gold standard for grafting, yet it suffers from a tendency to undergo resorption over time. While the exact mechanisms of this resorption remain elusive, osteocytes have been shown to play an important role in stimulating osteoclastic activity through their expression of receptor activator of NF-κB (RANK) ligand (RANKL). The aim of this study was to assess the function of osteocyte-derived RANKL in bone graft remodeling. MATERIALS AND METHODS In Tnfsf11fl/fl ;Dmp1-Cre mice without osteocyte-specific RANKL as well as in Dmp1-Cre control mice, 2.6 mm calvarial bone disks were harvested and transplanted into mice with matching genetic backgrounds either subcutaneously or subperiosteally, creating 4 groups in total. Histology and micro-computed tomography of the grafts and the donor regions were performed 28 days after grafting. RESULTS Histology revealed marked resorption of subcutaneous control Dmp1-Cre grafts and new bone formation around subperiosteal Dmp1-Cre grafts. In contrast, Tnfsf11fl/fl ;Dmp1-Cre grafts showed effectively neither signs of bone resorption nor formation. Quantitative micro-computed tomography revealed a significant difference in residual graft area between subcutaneous and subperiosteal Dmp1-Cre grafts (p < .01). This difference was not observed between subcutaneous and subperiosteal Tnfsf11fl/fl ;Dmp1-Cre grafts (p = .17). Residual graft volume (p = .08) and thickness (p = .13) did not differ significantly among the groups. Donor area regeneration was comparable between Tnfsf11fl/fl ;Dmp1-Cre and Dmp1-Cre mice and restricted to the defect margins. CONCLUSIONS The results suggest an active function of osteocyte-derived RANKL in bone graft remodeling.
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Affiliation(s)
- Balazs Feher
- Department of Oral Biology, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
- Department of Oral Surgery, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
- Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Carina Kampleitner
- Karl Donath Laboratory for Hard Tissue and Biomaterial Research, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
- Austrian Cluster for Tissue Regeneration, Vienna, Austria
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, Vienna, Austria
| | - Patrick Heimel
- Karl Donath Laboratory for Hard Tissue and Biomaterial Research, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
- Austrian Cluster for Tissue Regeneration, Vienna, Austria
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, Vienna, Austria
| | - Stefan Tangl
- Karl Donath Laboratory for Hard Tissue and Biomaterial Research, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
- Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Jill A Helms
- Department of Surgery, School of Medicine, Stanford University, Palo Alto, California, USA
| | - Ulrike Kuchler
- Department of Oral Surgery, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
| | - Reinhard Gruber
- Department of Oral Biology, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
- Austrian Cluster for Tissue Regeneration, Vienna, Austria
- Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland
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4
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Kerberger R, Brunello G, Drescher D, van Rietbergen B, Becker K. Micro finite element analysis of continuously loaded mini-implants - A micro-CT study in the rat tail model. Bone 2023; 177:116912. [PMID: 37739299 DOI: 10.1016/j.bone.2023.116912] [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: 07/08/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 09/24/2023]
Abstract
Implant migration has been described as a minor displacement of orthodontic mini-implants (OMIs) when subjected to constant forces. Aim of this study was to evaluate the impact of local stresses on implant migration and bone remodelling around constantly loaded OMIs. Two mini-implants were placed in one caudal vertebra of 61 rats, connected by a nickel‑titanium contraction spring, and loaded with different forces (0.0, 0.5, 1.0, 1.5 N). In vivo micro-CT scans were taken immediately and 1, 2 (n = 61), 4, 6 and 8 (n = 31) weeks post-op. Nine volumes of interest (VOIs) around each implant were defined. To analyse stress values, micro-finite element models were created. Bone remodelling was analysed by calculating the bone volume change between scans performed at consecutive time points. Statistical analysis was performed using a linear mixed model and likelihood-ratio-tests, followed by Tuckey post hoc tests when indicated. The highest stresses were observed in the proximal top VOI. In all VOIs, stress values tended to reach their maximum after two weeks and decreased thereafter. Bone remodelling analysis revealed initial bone loss within the first two weeks and bone gain up to week eight, which was noted especially in the highest loading group. The magnitude of local stresses influenced bone remodelling and it can be speculated that the stress related bone resorption favoured implant migration. After a first healing phase with a high degree of bone resorption, net bone gain representing consolidation was observed.
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Affiliation(s)
- Robert Kerberger
- Department of Orthodontics, University Hospital Düsseldorf, Moorenstraße 5, 40225 Düsseldorf, Germany; Department of Orthodontics and Dentofacial Orthopedics, Charité, Charité Centrum CC03, Institute for Dental and Craniofacial Sciences, Aßmannshauser Straße 4-6, 14197 Berlin, Germany.
| | - Giulia Brunello
- Department of Oral Surgery, University Hospital Düsseldorf, Moorenstraße 5, 40225 Düsseldorf, Germany; Department of Neurosciences, School of Dentistry, University of Padova, Via Giustiniani 2, 35128 Padova, Italy.
| | - Dieter Drescher
- Department of Orthodontics, University Hospital Düsseldorf, Moorenstraße 5, 40225 Düsseldorf, Germany.
| | - Bert van Rietbergen
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Groene Loper 3, 5612 AE Eindhoven, the Netherlands.
| | - Kathrin Becker
- Department of Orthodontics, University Hospital Düsseldorf, Moorenstraße 5, 40225 Düsseldorf, Germany; Department of Orthodontics and Dentofacial Orthopedics, Charité, Charité Centrum CC03, Institute for Dental and Craniofacial Sciences, Aßmannshauser Straße 4-6, 14197 Berlin, Germany.
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5
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Kim K, Su Y, Kucine AJ, Cheng K, Zhu D. Guided Bone Regeneration Using Barrier Membrane in Dental Applications. ACS Biomater Sci Eng 2023; 9:5457-5478. [PMID: 37650638 DOI: 10.1021/acsbiomaterials.3c00690] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Guided bone regeneration (GBR) is a widely used technique in preclinical and clinical studies due to its predictability. Its main purpose is to prevent the migration of soft tissue into the osseous wound space, while allowing osseous cells to migrate to the site. GBR is classified into two main categories: resorbable and non-resorbable membranes. Resorbable membranes do not require a second surgery but tend to have a short resorption period. Conversely, non-resorbable membranes maintain their mechanical strength and prevent collapse. However, they require removal and are susceptible to membrane exposure. GBR is often used with bone substitute graft materials to fill the defect space and protect the bone graft. The membrane can also undergo various modifications, such as surface modification and biological factor loading, to improve barrier functions and bone regeneration. In addition, bone regeneration is largely related to osteoimmunology, a new field that focuses on the interactions between bone and the immune system. Understanding these interactions can help in developing new treatments for bone diseases and injuries. Overall, GBR has the potential to be a powerful tool in promoting bone regeneration. Further research in this area could lead to advancements in the field of bone healing. This review will highlight resorbable and non-resorbable membranes with cellular responses during bone regeneration, provide insights into immunological response during bone remodeling, and discuss antibacterial features.
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Affiliation(s)
- Kakyung Kim
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York 11794, United States
| | - Yingchao Su
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York 11794, United States
| | - Allan J Kucine
- Department of Oral and Maxillofacial Surgery, Stony Brook University, Stony Brook, New York 11794, United States
| | - Ke Cheng
- Department of Biomedical Engineering, Columbia University, New York City, New York 10027, United States
| | - Donghui Zhu
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York 11794, United States
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6
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Hoppock GA, Buettmann EG, Denisco JA, Goldscheitter GM, Condyles SN, Juhl OJ, Friedman MA, Zhang Y, Donahue HJ. Connexin 43 and cell culture substrate differentially regulate OCY454 osteocytic differentiation and signaling to primary bone cells. Am J Physiol Cell Physiol 2023; 325:C907-C920. [PMID: 37602413 PMCID: PMC10635658 DOI: 10.1152/ajpcell.00220.2023] [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: 06/07/2023] [Revised: 08/10/2023] [Accepted: 08/12/2023] [Indexed: 08/22/2023]
Abstract
Connexin 43 (Cx43), the predominate gap junction protein in bone, is essential for intercellular communication and skeletal homeostasis. Previous work suggests that osteocyte-specific deletion of Cx43 leads to increased bone formation and resorption; however, the cell-autonomous role of osteocytic Cx43 in promoting increased bone remodeling is unknown. Recent studies using three-dimensional (3D) culture substrates in OCY454 cells suggest that 3D cultures may offer increased bone remodeling factor expression and secretion, such as sclerostin and receptor activator of nuclear factor-κB ligand (RANKL). In this study, we compared culturing OCY454 osteocytes on 3D Alvetex scaffolds with traditional 2D tissue culture, both with [wild-type (WT)] and without Cx43 (Cx43 KO). Conditioned media from OCY454 cell cultures were used to determine soluble signaling to differentiate primary bone marrow cells into osteoblasts and osteoclasts. OCY454 cells cultured on 3D portrayed a mature osteocytic phenotype, relative to cells on 2D, shown by increased osteocytic gene expression and reduced cell proliferation. In contrast, OCY454 differentiation based on these same markers was not affected by Cx43 deficiency in 3D. Interestingly, increased sclerostin secretion was found in 3D cultured WT cells compared with that of Cx43 KO cells. Conditioned media from Cx43 KO cells promoted increased osteoblastogenesis and osteoclastogenesis, with maximal effects from 3D cultured Cx43 KO cells. These results suggest that Cx43 deficiency promotes increased bone remodeling in a cell-autonomous manner with minimal changes in osteocyte differentiation. Finally, 3D cultures appear better suited to study mechanisms from Cx43-deficient OCY454 osteocytes in vitro due to their ability to promote osteocyte differentiation, limit proliferation, and increase bone remodeling factor secretion.NEW & NOTEWORTHY 3D cell culture of OCY454 cells promoted increased differentiation compared with traditional 2D culture. Although Cx43 deficiency did not affect OCY454 differentiation, it resulted in increased signaling, promoting osteoblastogenesis and osteoclastogenesis. Our results suggest that Cx43 deficiency promotes increased bone remodeling in a cell-autonomous manner with minimal changes in osteocyte differentiation. Also, 3D cultures appear better suited to study mechanisms in Cx43-deficient OCY454 osteocytes.
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Affiliation(s)
- Gabriel A Hoppock
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Evan G Buettmann
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Joseph A Denisco
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Galen M Goldscheitter
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Sebastian N Condyles
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Otto J Juhl
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Michael A Friedman
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Yue Zhang
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Henry J Donahue
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
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7
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Hoppock GA, Buettmann EG, Denisco JA, Goldscheitter GM, Condyles SN, Juhl OJ, Friedman MA, Zhang Y, Donahue HJ. Connexin 43 and Cell Culture Substrate Differentially Regulate OCY454 Osteocytic Differentiation and Signaling to Primary Bone Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.23.546276. [PMID: 37425674 PMCID: PMC10326966 DOI: 10.1101/2023.06.23.546276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Connexin 43 (Cx43), the predominate gap junction protein in bone, is essential for intercellular communication and skeletal homeostasis. Previous work suggests osteocyte-specific deletion of Cx43 leads to increased bone formation and resorption, however the cell-autonomous role of osteocytic Cx43 in promoting increased bone remodeling is unknown. Recent studies using 3D culture substrates in OCY454 cells suggest 3D cultures may offer increased bone remodeling factor expression and secretion, such as sclerostin and RANKL. In this study, we compared culturing OCY454 osteocytes on 3D Alvetex scaffolds to traditional 2D tissue culture, both with (WT) and without Cx43 (Cx43 KO). Conditioned media from OCY454 cell cultures was used to determine soluble signaling to differentiate primary bone marrow stromal cells into osteoblasts and osteoclasts. OCY454 cells cultured on 3D portrayed a mature osteocytic phenotype, relative to cells on 2D, shown by increased osteocytic gene expression and reduced cell proliferation. In contrast, OCY454 differentiation based on these same markers was not affected by Cx43 deficiency in 3D. Interestingly, increased sclerostin secretion was found in 3D cultured WT cells compared to Cx43 KO cells. Conditioned media from Cx43 KO cells promoted increased osteoblastogenesis and increased osteoclastogenesis, with maximal effects from 3D cultured Cx43 KO cells. These results suggest Cx43 deficiency promotes increased bone remodeling in a cell autonomous manner with minimal changes in osteocyte differentiation. Finally, 3D cultures appear better suited to study mechanisms from Cx43-deficient OCY454 osteocytes in vitro due to their ability to promote osteocyte differentiation, limit proliferation, and increase bone remodeling factor secretion. New and Noteworthy 3D cell culture of OCY454 cells promoted increased differentiation compared to traditional 2D culture. While Cx43 deficiency did not affect OCY454 differentiation, it resulted in increased signaling, promoting osteoblastogenesis and osteoclastogenesis. Our results suggest Cx43 deficiency promotes increased bone remodeling in a cell autonomous manner with minimal changes in osteocyte differentiation. Also, 3D cultures appear better suited to study mechanisms in Cx43-deficient OCY454 osteocytes.
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8
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Marahleh A, Kitaura H, Ohori F, Noguchi T, Mizoguchi I. The osteocyte and its osteoclastogenic potential. Front Endocrinol (Lausanne) 2023; 14:1121727. [PMID: 37293482 PMCID: PMC10244721 DOI: 10.3389/fendo.2023.1121727] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 04/07/2023] [Indexed: 06/10/2023] Open
Abstract
The skeleton is an organ of dual functionality; on the one hand, it provides protection and structural competence. On the other hand, it participates extensively in coordinating homeostasis globally given that it is a mineral and hormonal reservoir. Bone is the only tissue in the body that goes through strategically consistent bouts of bone resorption to ensure its integrity and organismal survival in a temporally and spatially coordinated process, known as bone remodeling. Bone remodeling is directly enacted by three skeletal cell types, osteoclasts, osteoblasts, and osteocytes; these cells represent the acting force in a basic multicellular unit and ensure bone health maintenance. The osteocyte is an excellent mechanosensory cell and has been positioned as the choreographer of bone remodeling. It is, therefore, not surprising that a holistic grasp of the osteocyte entity in the bone is warranted. This review discusses osteocytogenesis and associated molecular and morphological changes and describes the osteocytic lacunocanalicular network (LCN) and its organization. We highlight new knowledge obtained from transcriptomic analyses of osteocytes and discuss the regulatory role of osteocytes in promoting osteoclastogenesis with an emphasis on the case of osteoclastogenesis in anosteocytic bones. We arrive at the conclusion that osteocytes exhibit several redundant means through which osteoclast formation can be initiated. However, whether osteocytes are true "orchestrators of bone remodeling" cannot be verified from the animal models used to study osteocyte biology in vivo. Results from studying osteocyte biology using current animal models should come with the caveat that these models are not osteocyte-specific, and conclusions from these studies should be interpreted cautiously.
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Affiliation(s)
- Aseel Marahleh
- Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, Sendai, Japan
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Japan
| | - Hideki Kitaura
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Japan
| | - Fumitoshi Ohori
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Japan
| | - Takahiro Noguchi
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Japan
| | - Itaru Mizoguchi
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Japan
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9
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Wang JS, Tokavanich N, Wein MN. SP7: from Bone Development to Skeletal Disease. Curr Osteoporos Rep 2023; 21:241-252. [PMID: 36881265 PMCID: PMC10758296 DOI: 10.1007/s11914-023-00778-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/18/2023] [Indexed: 03/08/2023]
Abstract
PURPOSE OF REVIEW The purpose of this review is to summarize the different roles of the transcription factor SP7 in regulating bone formation and remodeling, discuss current studies in investigating the causal relationship between SP7 mutations and human skeletal disease, and highlight potential therapeutic treatments that targeting SP7 and the gene networks that it controls. RECENT FINDINGS Cell-type and stage-specific functions of SP7 have been identified during bone formation and remodeling. Normal bone development regulated by SP7 is strongly associated with human bone health. Dysfunction of SP7 results in common or rare skeletal diseases, including osteoporosis and osteogenesis imperfecta with different inheritance patterns. SP7-associated signaling pathways, SP7-dependent target genes, and epigenetic regulations of SP7 serve as new therapeutic targets in the treatment of skeletal disorders. This review addresses the importance of SP7-regulated bone development in studying bone health and skeletal disease. Recent advances in whole genome and exome sequencing, GWAS, multi-omics, and CRISPR-mediated activation and inhibition have provided the approaches to investigate the gene-regulatory networks controlled by SP7 in bone and the therapeutic targets to treat skeletal disease.
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Affiliation(s)
- Jialiang S Wang
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Nicha Tokavanich
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, USA
| | - Marc N Wein
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Harvard Stem Cell Institute, Cambridge, MA, USA
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10
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Puts R, Khaffaf A, Shaka M, Zhang H, Raum K. Focused Low-Intensity Pulsed Ultrasound (FLIPUS) Mitigates Apoptosis of MLO-Y4 Osteocyte-like Cells. Bioengineering (Basel) 2023; 10:bioengineering10030387. [PMID: 36978778 PMCID: PMC10045139 DOI: 10.3390/bioengineering10030387] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/01/2023] [Accepted: 03/15/2023] [Indexed: 03/30/2023] Open
Abstract
Long cytoplasmic processes of osteocytes orchestrate bone activity by integration of biochemical and mechanical signals and regulate load-induced bone adaptation. Low-Intensity Pulsed Ultrasound (LIPUS) is a clinically used technique for fracture healing that delivers mechanical impulses to the damaged bone tissue in a non-invasive and non-ionizing manner. The mechanism of action of LIPUS is still controversially discussed in the scientific community. In this study, the effect of focused LIPUS (FLIPUS) on the survival of starved MLO-Y4 osteocytes was investigated in vitro. Osteocytes stimulated for 10 min with FLIPUS exhibited extended dendrites, which formed frequent connections to neighboring cells and spanned longer distances. The sonicated cells displayed thick actin bundles and experienced increase in expression of connexin 43 (Cx43) proteins, especially on their dendrites, and E11 glycoprotein, which is responsible for the elongation of cellular cytoplasmic processes. After stimulation, expression of cell growth and survival genes as well as genes related to cell-cell communication was augmented. In addition, cell viability was improved after the sonication, and a decrease in ATP release in the medium was observed. In summary, FLIPUS mitigated apoptosis of starved osteocytes, which is likely related to the formation of the extensive dendritic network that ensured cell survival.
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Affiliation(s)
- Regina Puts
- Center for Biomedicine, Charité-Universitätsmedizin, 12203 Berlin, Germany
- Berlin Institute of Health (BIH) Center for Regenerative Therapies, Charité-Universitätsmedizin, 13353 Berlin, Germany
| | - Aseel Khaffaf
- Center for Biomedicine, Charité-Universitätsmedizin, 12203 Berlin, Germany
| | - Maria Shaka
- Center for Biomedicine, Charité-Universitätsmedizin, 12203 Berlin, Germany
| | - Hui Zhang
- Center for Biomedicine, Charité-Universitätsmedizin, 12203 Berlin, Germany
| | - Kay Raum
- Center for Biomedicine, Charité-Universitätsmedizin, 12203 Berlin, Germany
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11
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Marcucci G, Domazetovic V, Nediani C, Ruzzolini J, Favre C, Brandi ML. Oxidative Stress and Natural Antioxidants in Osteoporosis: Novel Preventive and Therapeutic Approaches. Antioxidants (Basel) 2023; 12:antiox12020373. [PMID: 36829932 PMCID: PMC9952369 DOI: 10.3390/antiox12020373] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/27/2023] [Accepted: 01/30/2023] [Indexed: 02/09/2023] Open
Abstract
This review reports in detail the cellular and molecular mechanisms which regulate the bone remodeling process in relation to oxidative stress (OS), inflammatory factors, and estrogen deficiency. OS is considered an important pathogenic factor of osteoporosis, inducing osteocyte apoptosis and varying levels of specific factors, such as receptor activator κB ligand (RANKL), sclerostin, and, according to recent evidence, fibroblast growth factor 23, with consequent impairment of bone remodeling and high bone resorption. Bone loss increases the risk of fragility fractures, and the most commonly used treatments are antiresorptive drugs, followed by anabolic drugs or those with a double effect. In addition, recent data show that natural antioxidants contained in the diet are efficient in preventing and reducing the negative effects of OS on bone remodeling and osteocytes through the involvement of sirtuin type 1 enzyme. Indeed, osteocytes and some of their molecular factors are considered potential biological targets on which antioxidants can act to prevent and reduce bone loss, as well as to promote bone anabolic and regenerative processes by restoring physiological bone remodeling. Several data suggest including antioxidants in novel therapeutic approaches to develop better management strategies for the prevention and treatment of osteoporosis and OS-related bone diseases. In particular, anthocyanins, as well as resveratrol, lycopene, oleuropein, some vitamins, and thiol antioxidants, could have protective and therapeutic anti-osteoporotic effects.
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Affiliation(s)
- Gemma Marcucci
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy
| | - Vladana Domazetovic
- Department of Paediatric Haematology-Oncology, Meyer Children’s Hospital IRCCS, 50139 Florence, Italy
| | - Chiara Nediani
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy
- Correspondence:
| | - Jessica Ruzzolini
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy
| | - Claudio Favre
- Department of Paediatric Haematology-Oncology, Meyer Children’s Hospital IRCCS, 50139 Florence, Italy
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12
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Wakefield B, Penuela S. Potential Implications of Exercise Training on Pannexin Expression and Function. J Vasc Res 2022; 60:114-124. [PMID: 36366809 DOI: 10.1159/000527240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 09/14/2022] [Indexed: 09/05/2023] Open
Abstract
Pannexins (PANX1, 2, 3) are channel-forming glycoproteins that are expressed throughout the cardiovascular and musculoskeletal system. The canonical function of these proteins is to release nucleotides that act as purinergic signalling at the cell membrane or Ca2+ channels at the endoplasmic reticulum membrane. These two forms of signalling are essential for autocrine and paracrine signalling in health, and alterations in this signalling have been implicated in the pathogenesis of many diseases. Many musculoskeletal and cardiovascular diseases are largely the result of a lack of physical activity which causes altered gene expression. Considering exercise training has been shown to alter a wide array of gene expression in musculoskeletal tissues, understanding the interaction between exercise training, gene function and expression in relevant diseases is warranted. With regards to pannexins, multiple publications have shown that exercise training can influence pannexin expression and may influence the significance of its function in certain diseases. This review further discusses the potential interaction between exercise training and pannexin biology in relevant tissues and disease models. We propose that exercise training in relevant animal and human models will provide a more comprehensive understanding of the implications of pannexin biology in disease.
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Affiliation(s)
- Brent Wakefield
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
- Western's Bone and Joint Institute, The Dr. Sandy Kirkley Centre for Musculoskeletal Research, University Hospital, London, Ontario, Canada
| | - Silvia Penuela
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
- Western's Bone and Joint Institute, The Dr. Sandy Kirkley Centre for Musculoskeletal Research, University Hospital, London, Ontario, Canada
- Department of Oncology, Division of Experimental Oncology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
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13
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Sirisereephap K, Maekawa T, Tamura H, Hiyoshi T, Domon H, Isono T, Terao Y, Maeda T, Tabeta K. Osteoimmunology in Periodontitis: Local Proteins and Compounds to Alleviate Periodontitis. Int J Mol Sci 2022; 23:ijms23105540. [PMID: 35628348 PMCID: PMC9146968 DOI: 10.3390/ijms23105540] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 05/13/2022] [Accepted: 05/14/2022] [Indexed: 01/25/2023] Open
Abstract
Periodontitis is one of the most common oral diseases resulting in gingival inflammation and tooth loss. Growing evidence indicates that it results from dysbiosis of the oral microbiome, which interferes with the host immune system, leading to bone destruction. Immune cells activate periodontal ligament cells to express the receptor activator of nuclear factor kappa-B (NF-κB) ligand (RANKL) and promote osteoclast activity. Osteocytes have active roles in periodontitis progression in the bone matrix. Local proteins are involved in bone regeneration through functional immunological plasticity. Here, we discuss the current knowledge of cellular and molecular mechanisms in periodontitis, the roles of local proteins, and promising synthetic compounds generating a periodontal regeneration effect. It is anticipated that this may lead to a better perception of periodontitis pathophysiology.
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Affiliation(s)
- Kridtapat Sirisereephap
- Division of Periodontology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan; (K.S.); (H.T.); (K.T.)
- Center for Advanced Oral Science, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan; (T.H.); (T.M.)
- Faculty of Dentistry, Chulalongkorn University, Bangkok 10330, Thailand
| | - Tomoki Maekawa
- Center for Advanced Oral Science, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan; (T.H.); (T.M.)
- Correspondence: ; Tel.: +81-25-227-2828
| | - Hikaru Tamura
- Division of Periodontology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan; (K.S.); (H.T.); (K.T.)
| | - Takumi Hiyoshi
- Center for Advanced Oral Science, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan; (T.H.); (T.M.)
| | - Hisanori Domon
- Division of Microbiology and Infectious Disease, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan; (H.D.); (T.I.); (Y.T.)
| | - Toshihito Isono
- Division of Microbiology and Infectious Disease, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan; (H.D.); (T.I.); (Y.T.)
| | - Yutaka Terao
- Division of Microbiology and Infectious Disease, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan; (H.D.); (T.I.); (Y.T.)
| | - Takeyasu Maeda
- Center for Advanced Oral Science, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan; (T.H.); (T.M.)
| | - Koichi Tabeta
- Division of Periodontology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan; (K.S.); (H.T.); (K.T.)
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14
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Hoenig T, Ackerman KE, Beck BR, Bouxsein ML, Burr DB, Hollander K, Popp KL, Rolvien T, Tenforde AS, Warden SJ. Bone stress injuries. Nat Rev Dis Primers 2022; 8:26. [PMID: 35484131 DOI: 10.1038/s41572-022-00352-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/11/2022] [Indexed: 01/11/2023]
Abstract
Bone stress injuries, including stress fractures, are overuse injuries that lead to substantial morbidity in active individuals. These injuries occur when excessive repetitive loads are introduced to a generally normal skeleton. Although the precise mechanisms for bone stress injuries are not completely understood, the prevailing theory is that an imbalance in bone metabolism favours microdamage accumulation over its removal and replacement with new bone via targeted remodelling. Diagnosis is achieved by a combination of patient history and physical examination, with imaging used for confirmation. Management of bone stress injuries is guided by their location and consequent risk of healing complications. Bone stress injuries at low-risk sites typically heal with activity modification followed by progressive loading and return to activity. Additional treatment approaches include non-weight-bearing immobilization, medications or surgery, but these approaches are usually limited to managing bone stress injuries that occur at high-risk sites. A comprehensive strategy that integrates anatomical, biomechanical and biological risk factors has the potential to improve the understanding of these injuries and aid in their prevention and management.
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Affiliation(s)
- Tim Hoenig
- Department of Trauma and Orthopaedic Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Kathryn E Ackerman
- Wu Tsai Female Athlete Program, Boston Children's Hospital, Boston, MA, USA.,Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Belinda R Beck
- School of Health Sciences & Social Work, Griffith University, Gold Coast, Queensland, Australia.,Menzies Health Institute Queensland, Gold Coast, Queensland, Australia.,The Bone Clinic, Brisbane, Queensland, Australia
| | - Mary L Bouxsein
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.,Department of Orthopedic Surgery, Harvard Medical School and Center for Advanced Orthopedic Studies, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - David B Burr
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indiana University, Indianapolis, IN, USA.,Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indiana University, Indianapolis, IN, USA
| | - Karsten Hollander
- Institute of Interdisciplinary Exercise Science and Sports Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Kristin L Popp
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.,U.S. Army Research Institute of Environmental Medicine, Natick, MA, USA
| | - Tim Rolvien
- Department of Trauma and Orthopaedic Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Adam S Tenforde
- Spaulding Rehabilitation Hospital, Department of Physical Medicine and Rehabilitation, Harvard Medical School, Charlestown, MA, USA.
| | - Stuart J Warden
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indiana University, Indianapolis, IN, USA. .,Department of Physical Therapy, School of Health & Human Sciences, Indiana University, Indianapolis, IN, USA. .,La Trobe Sport and Exercise Medicine Research Centre, La Trobe University, Bundoora, Victoria, Australia.
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15
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Choi JUA, Kijas AW, Lauko J, Rowan AE. The Mechanosensory Role of Osteocytes and Implications for Bone Health and Disease States. Front Cell Dev Biol 2022; 9:770143. [PMID: 35265628 PMCID: PMC8900535 DOI: 10.3389/fcell.2021.770143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 12/13/2021] [Indexed: 12/14/2022] Open
Abstract
Bone homeostasis is a dynamic equilibrium between bone-forming osteoblasts and bone-resorbing osteoclasts. This process is primarily controlled by the most abundant and mechanosensitive bone cells, osteocytes, that reside individually, within chambers of porous hydroxyapatite bone matrix. Recent studies have unveiled additional functional roles for osteocytes in directly contributing to local matrix regulation as well as systemic roles through endocrine functions by communicating with distant organs such as the kidney. Osteocyte function is governed largely by both biochemical signaling and the mechanical stimuli exerted on bone. Mechanical stimulation is required to maintain bone health whilst aging and reduced level of loading are known to result in bone loss. To date, both in vivo and in vitro approaches have been established to answer important questions such as the effect of mechanical stimuli, the mechanosensors involved, and the mechanosensitive signaling pathways in osteocytes. However, our understanding of osteocyte mechanotransduction has been limited due to the technical challenges of working with these cells since they are individually embedded within the hard hydroxyapatite bone matrix. This review highlights the current knowledge of the osteocyte functional role in maintaining bone health and the key regulatory pathways of these mechanosensitive cells. Finally, we elaborate on the current therapeutic opportunities offered by existing treatments and the potential for targeting osteocyte-directed signaling.
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Affiliation(s)
- Jung Un Ally Choi
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Amanda W Kijas
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Jan Lauko
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Alan E Rowan
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
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16
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Domazetovic V, Falsetti I, Ciuffi S, Iantomasi T, Marcucci G, Vincenzini MT, Brandi ML. Effect of Oxidative Stress-Induced Apoptosis on Active FGF23 Levels in MLO-Y4 Cells: The Protective Role of 17-β-Estradiol. Int J Mol Sci 2022; 23:ijms23042103. [PMID: 35216216 PMCID: PMC8879671 DOI: 10.3390/ijms23042103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/10/2022] [Accepted: 02/11/2022] [Indexed: 12/04/2022] Open
Abstract
The discovery that osteocytes secrete phosphaturic fibroblast growth factor 23 (FGF23) has defined bone as an endocrine organ. However, the autocrine and paracrine functions of FGF23 are still unknown. The present study focuses on the cellular and molecular mechanisms involved in the complex control of FGF23 production and local bone remodeling functions. FGF23 was assayed using ELISA kit in the presence or absence of 17β–estradiol in starved MLO-Y4 osteocytes. In these cells, a relationship between oxidative stress-induced apoptosis and up-regulation of active FGF23 levels due to MAP Kinases activation with involvement of the transcriptional factor (NF-kB) has been demonstrated. The active FGF23 increase can be due to up-regulation of its expression and post-transcriptional modifications. 17β–estradiol prevents the increase of FGF23 by inhibiting JNK and NF-kB activation, osteocyte apoptosis and by the down-regulation of osteoclastogenic factors, such as sclerostin. No alteration in the levels of dentin matrix protein 1, a FGF23 negative regulator, has been determined. The results of this study identify biological targets on which drugs and estrogen may act to control active FGF23 levels in oxidative stress-related bone and non-bone inflammatory diseases.
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Affiliation(s)
- Vladana Domazetovic
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy; (V.D.); (I.F.); (S.C.); (T.I.); (G.M.); (M.T.V.)
| | - Irene Falsetti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy; (V.D.); (I.F.); (S.C.); (T.I.); (G.M.); (M.T.V.)
| | - Simone Ciuffi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy; (V.D.); (I.F.); (S.C.); (T.I.); (G.M.); (M.T.V.)
| | - Teresa Iantomasi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy; (V.D.); (I.F.); (S.C.); (T.I.); (G.M.); (M.T.V.)
| | - Gemma Marcucci
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy; (V.D.); (I.F.); (S.C.); (T.I.); (G.M.); (M.T.V.)
| | - Maria Teresa Vincenzini
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy; (V.D.); (I.F.); (S.C.); (T.I.); (G.M.); (M.T.V.)
| | - Maria Luisa Brandi
- Fondazione Italiana Ricerca sulle Malattie dell’Osso (FIRMO Onlus), 50141 Florence, Italy
- Correspondence:
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17
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Abstract
PURPOSE OF REVIEW Osteocytes are considered to be the cells responsible for mastering the remodeling process that follows the exposure to unloading conditions. Given the invasiveness of bone biopsies in humans, both rodents and in vitro culture systems are largely adopted as models for studies in space missions or in simulated microgravity conditions models on Earth. RECENT FINDINGS After a brief recall of the main changes in bone mass and osteoclastic and osteoblastic activities in space-related models, this review focuses on the potential role of osteocytes in directing these changes. The role of the best-known signalling molecules is questioned, in particular in relation to osteocyte apoptosis. The mechanotransduction actors identified in spatial conditions and the problems related to fluid flow and shear stress changes, probably enhanced by the alteration in fluid flow and lack of convection during spaceflight, are recalled and discussed.
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Affiliation(s)
- Donata Iandolo
- U1059 INSERM - SAINBIOSE (SAnté INgéniérie BIOlogie St-Etienne) Campus Santé Innovation, Université Jean Monnet, Saint-Priest-en-Jarez, France
| | - Maura Strigini
- U1059 INSERM - SAINBIOSE (SAnté INgéniérie BIOlogie St-Etienne) Campus Santé Innovation, Université Jean Monnet, Saint-Priest-en-Jarez, France
| | - Alain Guignandon
- U1059 INSERM - SAINBIOSE (SAnté INgéniérie BIOlogie St-Etienne) Campus Santé Innovation, Université Jean Monnet, Saint-Priest-en-Jarez, France
| | - Laurence Vico
- U1059 INSERM - SAINBIOSE (SAnté INgéniérie BIOlogie St-Etienne) Campus Santé Innovation, Université Jean Monnet, Saint-Priest-en-Jarez, France.
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18
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Wang JS, Kamath T, Mazur CM, Mirzamohammadi F, Rotter D, Hojo H, Castro CD, Tokavanich N, Patel R, Govea N, Enishi T, Wu Y, da Silva Martins J, Bruce M, Brooks DJ, Bouxsein ML, Tokarz D, Lin CP, Abdul A, Macosko EZ, Fiscaletti M, Munns CF, Ryder P, Kost-Alimova M, Byrne P, Cimini B, Fujiwara M, Kronenberg HM, Wein MN. Control of osteocyte dendrite formation by Sp7 and its target gene osteocrin. Nat Commun 2021; 12:6271. [PMID: 34725346 PMCID: PMC8560803 DOI: 10.1038/s41467-021-26571-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 10/12/2021] [Indexed: 02/05/2023] Open
Abstract
Some osteoblasts embed within bone matrix, change shape, and become dendrite-bearing osteocytes. The circuitry that drives dendrite formation during "osteocytogenesis" is poorly understood. Here we show that deletion of Sp7 in osteoblasts and osteocytes causes defects in osteocyte dendrites. Profiling of Sp7 target genes and binding sites reveals unexpected repurposing of this transcription factor to drive dendrite formation. Osteocrin is a Sp7 target gene that promotes osteocyte dendrite formation and rescues defects in Sp7-deficient mice. Single-cell RNA-sequencing demonstrates defects in osteocyte maturation in the absence of Sp7. Sp7-dependent osteocyte gene networks are associated with human skeletal diseases. Moreover, humans with a SP7R316C mutation show defective osteocyte morphology. Sp7-dependent genes that mark osteocytes are enriched in neurons, highlighting shared features between osteocytic and neuronal connectivity. These findings reveal a role for Sp7 and its target gene Osteocrin in osteocytogenesis, revealing that pathways that control osteocyte development influence human bone diseases.
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Affiliation(s)
- Jialiang S Wang
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Tushar Kamath
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Courtney M Mazur
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Fatemeh Mirzamohammadi
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Plastic and Reconstructive Surgery, Wright State University, Dayton, OH, USA
| | - Daniel Rotter
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- University of Applied Sciences Technikum Wien, Vienna, Austria
| | - Hironori Hojo
- Center for Disease Biology and Integrative Medicine, The University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Christian D Castro
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Nicha Tokavanich
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Rushi Patel
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Nicolas Govea
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Anesthesiology, Weill Cornell Medical School, New York, NY, USA
| | - Tetsuya Enishi
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Orthopedic Surgery, Tokushima Municipal Hospital, Tokushima, Japan
| | - Yunshu Wu
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | | | - Michael Bruce
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Daniel J Brooks
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Center for Advanced Orthopedic Studies, Department of Orthopedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MaA, USA
| | - Mary L Bouxsein
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Center for Advanced Orthopedic Studies, Department of Orthopedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MaA, USA
| | - Danielle Tokarz
- Advanced Microscopy Program, Center for Systems Biology and Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Chemistry, Saint Mary's University, Halifax, Canada
| | - Charles P Lin
- Advanced Microscopy Program, Center for Systems Biology and Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Abdul Abdul
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Evan Z Macosko
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Melissa Fiscaletti
- Pediatric Department, Sainte-Justine University Hospital Centre, Montreal, Canada
| | - Craig F Munns
- Institute of Endocrinology and Diabetes, The Children's Hospital at Westmead, Sydney, NSW, Australia
- Discipline of Paediatrics & Child Health, University of Sydney, Sydney, 2006, Australia
| | - Pearl Ryder
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Broad Institute of Harvard and MIT, Imaging Platform, Cambridge, MA, USA
| | - Maria Kost-Alimova
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Broad Institute of Harvard and MIT, Center for the Development of Therapeutics, Cambridge, MA, USA
| | - Patrick Byrne
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Broad Institute of Harvard and MIT, Center for the Development of Therapeutics, Cambridge, MA, USA
| | - Beth Cimini
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Broad Institute of Harvard and MIT, Imaging Platform, Cambridge, MA, USA
| | - Makoto Fujiwara
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Henry M Kronenberg
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Marc N Wein
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
- Broad Institute of Harvard and MIT, Cambridge, MA, USA.
- Harvard Stem Cell Institute, Cambridge, MA, USA.
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19
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Jähn-Rickert K, Zimmermann EA. Potential Role of Perilacunar Remodeling in the Progression of Osteoporosis and Implications on Age-Related Decline in Fracture Resistance of Bone. Curr Osteoporos Rep 2021; 19:391-402. [PMID: 34117624 DOI: 10.1007/s11914-021-00686-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/22/2021] [Indexed: 12/21/2022]
Abstract
PURPOSE OF REVIEW We took an interdisciplinary view to examine the potential contribution of perilacunar/canalicular remodeling to declines in bone fracture resistance related to age or progression of osteoporosis. RECENT FINDINGS Perilacunar remodeling is most prominent as a result of lactation; recent advances further elucidate the molecular players involved and their effect on bone material properties. Of these, vitamin D and calcitonin could be active during aging or osteoporosis. Menopause-related hormonal changes or osteoporosis therapies affect bone material properties and mechanical behavior. However, investigations of lacunar size or osteocyte TRAP activity with age or osteoporosis do not provide clear evidence for or against perilacunar remodeling. While the occurrence and potential role of perilacunar remodeling in aging and osteoporosis progression are largely under-investigated, widespread changes in bone matrix composition in OVX models and following osteoporosis therapies imply osteocytic maintenance of bone matrix. Perilacunar remodeling-induced changes in bone porosity, bone matrix composition, and bone adaptation could have significant implications for bone fracture resistance.
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Affiliation(s)
- Katharina Jähn-Rickert
- Heisenberg Research Group, Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 55a, 22529, Hamburg, Germany.
- Mildred Scheel Cancer Career Center Hamburg, University Cancer Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Elizabeth A Zimmermann
- Faculty of Dentistry, McGill University, Strathcona Anatomy and Dentistry Building, 3640 Rue University, Montreal, Canada.
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20
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Juhl OJ, Buettmann EG, Friedman MA, DeNapoli RC, Hoppock GA, Donahue HJ. Update on the effects of microgravity on the musculoskeletal system. NPJ Microgravity 2021; 7:28. [PMID: 34301942 PMCID: PMC8302614 DOI: 10.1038/s41526-021-00158-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 06/28/2021] [Indexed: 02/07/2023] Open
Abstract
With the reignited push for manned spaceflight and the development of companies focused on commercializing spaceflight, increased human ventures into space are inevitable. However, this venture would not be without risk. The lower gravitational force, known as microgravity, that would be experienced during spaceflight significantly disrupts many physiological systems. One of the most notably affected systems is the musculoskeletal system, where exposure to microgravity causes both bone and skeletal muscle loss, both of which have significant clinical implications. In this review, we focus on recent advancements in our understanding of how exposure to microgravity affects the musculoskeletal system. We will focus on the catabolic effects microgravity exposure has on both bone and skeletal muscle cells, as well as their respective progenitor stem cells. Additionally, we report on the mechanisms that underlie bone and muscle tissue loss resulting from exposure to microgravity and then discuss current countermeasures being evaluated. We reveal the gaps in the current knowledge and expound upon how current research is filling these gaps while also identifying new avenues of study as we continue to pursue manned spaceflight.
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Affiliation(s)
- Otto J Juhl
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Evan G Buettmann
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Michael A Friedman
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Rachel C DeNapoli
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Gabriel A Hoppock
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Henry J Donahue
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA.
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21
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Cibelli A, Veronica Lopez-Quintero S, Mccutcheon S, Scemes E, Spray DC, Stout RF, Suadicani SO, Thi MM, Urban-Maldonado M. Generation and Characterization of Immortalized Mouse Cortical Astrocytes From Wildtype and Connexin43 Knockout Mice. Front Cell Neurosci 2021; 15:647109. [PMID: 33790744 PMCID: PMC8005635 DOI: 10.3389/fncel.2021.647109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/18/2021] [Indexed: 11/17/2022] Open
Abstract
We transduced mouse cortical astrocytes cultured from four litters of embryonic wildtype (WT) and connexin43 (Cx43) null mouse pups with lentiviral vector encoding hTERT and measured expression of astrocyte-specific markers up to passage 10 (p10). The immortalized cell lines thus generated (designated IWCA and IKOCA, respectively) expressed biomarkers consistent with those of neonatal astrocytes, including Cx43 from wildtype but not from Cx43-null mice, lack of Cx30, and presence of Cx26. AQP4, the water channel that is found in high abundance in astrocyte end-feet, was expressed at moderately high levels in early passages, and its mRNA and protein declined to low but still detectable levels by p10. The mRNA levels of the astrocyte biomarkers aldehyde dehydrogenase 1L1 (ALDH1L1), glutamine synthetase (GS) and glial fibrillary acidic protein (GFAP) remained relatively constant during successive passages. GS protein expression was maintained while GFAP declined with cell passaging but was still detectable at p10. Both mRNA and protein levels of glutamate transporter 1 (GLT-1) declined with passage number. Immunostaining at corresponding times was consistent with the data from Western blots and provided evidence that these proteins were expressed at appropriate intracellular locations. Consistent with our goal of generating immortalized cell lines in which Cx43 was either functionally expressed or absent, IWCA cells were found to be well coupled with respect to intercellular dye transfer and similar to primary astrocyte cultures in terms of time course of junction formation, electrical coupling strength and voltage sensitivity. Moreover, barrier function was enhanced in co-culture of the IWCA cell line with bEnd.3 microvascular endothelial cells. In addition, immunostaining revealed oblate endogenous Cx43 gap junction plaques in IWCA that were similar in appearance to those plaques obtained following transfection of IKOCA cells with fluorescent protein tagged Cx43. Re-expression of Cx43 in IKOCA cells allows experimental manipulation of connexins and live imaging of interactions between connexins and other proteins. We conclude that properties of these cell lines resemble those of primary cultured astrocytes, and they may provide useful tools in functional studies by facilitating genetic and pharmacological manipulations in the context of an astrocyte-appropriate cellular environment.
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Affiliation(s)
- Antonio Cibelli
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States
| | | | - Sean Mccutcheon
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States
| | - Eliana Scemes
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States
| | - David C. Spray
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States,Department of Medicine (Cardiology), Albert Einstein College of Medicine, New York, NY, United States,*Correspondence: David C. Spray,
| | - Randy F. Stout
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States,Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, New York, NY, United States,Randy J. Stout Jr.,
| | - Sylvia O. Suadicani
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States,Department of Urology, Albert Einstein College of Medicine, New York, NY, United States,Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY, United States
| | - Mia M. Thi
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States,Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY, United States,Department of Orthopaedic Surgery, Albert Einstein College of Medicine, New York, NY, United States
| | - Marcia Urban-Maldonado
- Department of Urology, Albert Einstein College of Medicine, New York, NY, United States,Department of Orthopaedic Surgery, Albert Einstein College of Medicine, New York, NY, United States
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22
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Huang X, Xie M, Xie Y, Mei F, Lu X, Li X, Chen L. The roles of osteocytes in alveolar bone destruction in periodontitis. J Transl Med 2020; 18:479. [PMID: 33308247 PMCID: PMC7733264 DOI: 10.1186/s12967-020-02664-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/03/2020] [Indexed: 02/06/2023] Open
Abstract
Periodontitis, a bacterium-induced inflammatory disease that is characterized by alveolar bone loss, is highly prevalent worldwide. Elucidating the underlying mechanisms of alveolar bone loss in periodontitis is crucial for understanding its pathogenesis. Classically, bone cells, such as osteoclasts, osteoblasts and bone marrow stromal cells, are thought to dominate the development of bone destruction in periodontitis. Recently, osteocytes, the cells embedded in the mineral matrix, have gained attention. This review demonstrates the key contributing role of osteocytes in periodontitis, especially in alveolar bone loss. Osteocytes not only initiate physiological bone remodeling but also assist in inflammation-related changes in bone remodeling. The latest evidence suggests that osteocytes are involved in regulating bone anabolism and catabolism in the progression of periodontitis. The altered secretion of receptor activator of NF-κB ligand (RANKL), sclerostin and Dickkopf-related protein 1 (DKK1) by osteocytes affects the balance of bone resorption and formation and promotes bone loss. In addition, the accumulation of prematurely senescent and apoptotic osteocytes observed in alveolar bone may exacerbate local destruction. Based on their communication with the bloodstream, it is noteworthy that osteocytes may participate in the interaction between local periodontitis lesions and systemic diseases. Overall, further investigations of osteocytes may provide vital insights that improve our understanding of the pathophysiology of periodontitis.
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Affiliation(s)
- Xiaofei Huang
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, 430022, China
| | - Mengru Xie
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, 430022, China
| | - Yanling Xie
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, 430022, China
| | - Feng Mei
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, 430022, China
| | - Xiaofeng Lu
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, 430022, China
| | - Xiaoshuang Li
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China. .,Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, 430022, China.
| | - Lili Chen
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China. .,Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, 430022, China.
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23
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Lateral static overload on immediately restored implants decreases the osteocyte index in peri-implant bone: a secondary analysis of a pre-clinical study in dogs. Clin Oral Investig 2020; 25:3297-3303. [PMID: 33150510 DOI: 10.1007/s00784-020-03662-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 10/27/2020] [Indexed: 01/08/2023]
Abstract
OBJECTIVES This animal study was conducted to evaluate the osteocyte index in the peri-implant bone around immediately restored implants under static lateral overload. MATERIAL AND METHODS Seven mongrel dogs received three implants on each side of the mandible. Forty-two implants were distributed into three groups (14 implants per group); each animal received two implants connected to a 4.5-mm opened expansion device (experimental group); in the other mandible side, two implants were connected into an expansion device without activation (control group); one implant each side of the mandible was left submerged (unload group). After 4 months under daily mechanical and chemical plaque control, the animals were euthanized; dental implants and surrounding bone were removed and processed to obtain thin ground sections. Histomorphometry was used to evaluate the osteocyte index in the peri-implant bone contact to implant. RESULTS A higher, statistically significant mean number of osteocytes × 10-5 μm2 (54.74 ± 23.91) was found in the control group compared with the test group (22.57 ± 22.55) (p = 0.0221). The correlation between percentage of bone-implant contact and osteocyte index for submerged implants was not statistically significant (p = 0.2667), whereas the value for immediately loaded implants was statistically significant (p = 0.0480). CONCLUSION The lower number of osteocytes in the peri-implant bone around overloaded implants could be related to the need for functional adaptation of the bone tissue to overloading and to the hypothesized involvement of the osteocytes in the maintenance of the bone matrix in the control group. CLINICAL RELEVANCE Osteocytes play a pivotal role in bone adaptation to mechanical loading, and the osteocyte network has been regarded as being the main mechanosensory mechanism.
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24
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Yang J, Dong D, Luo X, Zhou J, Shang P, Zhang H. Iron Overload-Induced Osteocyte Apoptosis Stimulates Osteoclast Differentiation Through Increasing Osteocytic RANKL Production In Vitro. Calcif Tissue Int 2020; 107:499-509. [PMID: 32995951 DOI: 10.1007/s00223-020-00735-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/21/2020] [Indexed: 12/23/2022]
Abstract
Iron overload is closely associated with osteoporosis, the potential cellular mechanism involved in decreased osteoblast differentiation and increased osteoclast formation. However, the effect of iron overload on the biological behavior in osteocytes has not been reported. This study aims to investigate the changes of osteocytic activity, apoptosis, and its regulation on osteoclastogenesis in response to iron overload. MLO-Y4 osteocyte-like cells and primary osteocytes from mice were processed with ferric ammonium citrate (FAC) and deferoxamine (DFO), the conditioned medium (CM) was harvested and co-cultured with Raw264.7 cells and bone marrow-derived macrophages (BMDMs) to induce them to differentiate into osteoclasts. Osteocyte apoptosis, osteoclast differentiation, osteocytic gene expression and protein secretion of receptor activator of nuclear factor κB ligand (RANKL) and osteoprotegerin (OPG) was examined. Excessive iron has a toxic effect on MLO-Y4 osteocyte-like cells. Increased cell apoptosis in MLO-Y4 cells and primary osteocytes was induced by iron overload. The osteoclastic formation, differentiation-related gene expression, and osteoclastic bone-resorption capability were significantly increased after treated with the CM from iron overload-exposed osteocytes. Excessive iron exposure significantly promoted the gene expression and protein secretion of the RANKL in MLO-Y4 cells. Addition of RANKL-blocking antibody completely abolished the increase of osteoclast formation and bone resorption capacity induced by the CM from osteocytes exposed to excessive iron. Moreover, the pan-caspase apoptosis inhibitor, QVD (quinolyl-valyl-O-methylaspartyl-[-2,6-difluorophenoxy]-methylketone) was used to inhibit osteocyte apoptosis. The results showed osteocyte apoptosis induced by iron overload was reduced by QVD and accompanied by the decrease of soluble RANKL (sRANKL) in supernatant. The increase of osteoclast formation and bone resorption capacity induced by the CM from osteocytes exposed to excessive iron was significantly decreased by QVD. These results indicated that iron overload-induced osteocyte apoptosis is required to regulate osteoclast differentiation by increasing osteocytic RANKL production. This study, for the first time, reveals the indirect effect of iron overload on osteoclast differentiation through regulating osteocytes.
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Affiliation(s)
- Jiancheng Yang
- Department of Spine Surgery, People's Hospital of Longhua, Affiliated Hospital of Southern Medical University, No. 38, Jinglong Construction Road, Shenzhen, 518109, Guangdong, China
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, 127 West Youyi Road, Beilin District, Xi'an, 710072, Shaanxi, China
| | - Dandan Dong
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, 127 West Youyi Road, Beilin District, Xi'an, 710072, Shaanxi, China
| | - Xinle Luo
- Department of Spine Surgery, People's Hospital of Longhua, Affiliated Hospital of Southern Medical University, No. 38, Jinglong Construction Road, Shenzhen, 518109, Guangdong, China
- The Third School of Clinical Medicine, Southern Medical University, Shenzhen, China
| | - Jianhua Zhou
- Department of Spine Surgery, People's Hospital of Longhua, Affiliated Hospital of Southern Medical University, No. 38, Jinglong Construction Road, Shenzhen, 518109, Guangdong, China
| | - Peng Shang
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, 127 West Youyi Road, Beilin District, Xi'an, 710072, Shaanxi, China.
- Research & Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen, China.
| | - Hao Zhang
- Department of Spine Surgery, People's Hospital of Longhua, Affiliated Hospital of Southern Medical University, No. 38, Jinglong Construction Road, Shenzhen, 518109, Guangdong, China.
- The Third School of Clinical Medicine, Southern Medical University, Shenzhen, China.
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25
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Zhang S, Markey M, Pena CD, Venkatesh T, Vazquez M. A Micro-Optic Stalk (μOS) System to Model the Collective Migration of Retinal Neuroblasts. MICROMACHINES 2020; 11:mi11040363. [PMID: 32244321 PMCID: PMC7230939 DOI: 10.3390/mi11040363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 03/27/2020] [Accepted: 03/28/2020] [Indexed: 12/18/2022]
Abstract
Contemporary regenerative therapies have introduced stem-like cells to replace damaged neurons in the visual system by recapitulating critical processes of eye development. The collective migration of neural stem cells is fundamental to retinogenesis and has been exceptionally well-studied using the fruit fly model of Drosophila Melanogaster. However, the migratory behavior of its retinal neuroblasts (RNBs) has been surprisingly understudied, despite being critical to retinal development in this invertebrate model. The current project developed a new microfluidic system to examine the collective migration of RNBs extracted from the developing visual system of Drosophila as a model for the collective motile processes of replacement neural stem cells. The system scales with the microstructure of the Drosophila optic stalk, which is a pre-cursor to the optic nerve, to produce signaling fields spatially comparable to in vivo RNB stimuli. Experiments used the micro-optic stalk system, or μOS, to demonstrate the preferred sizing and directional migration of collective, motile RNB groups in response to changes in exogenous concentrations of fibroblast growth factor (FGF), which is a key factor in development. Our data highlight the importance of cell-to-cell contacts in enabling cell cohesion during collective RNB migration and point to the unexplored synergy of invertebrate cell study and microfluidic platforms to advance regenerative strategies.
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Affiliation(s)
- Stephanie Zhang
- Department of Biomedical Engineering, Binghamton University, 4400 Vestal Pkwy E, Binghamton, NY 13902, USA;
| | - Miles Markey
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Rd, Piscataway, NJ 08854, USA;
| | - Caroline D. Pena
- Department of Biomedical Engineering, City College of New York, New York City, NY 10031, USA;
| | - Tadmiri Venkatesh
- Department of Biology, City College of New York, New York City, NY 10031, USA;
| | - Maribel Vazquez
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Rd, Piscataway, NJ 08854, USA;
- Correspondence:
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26
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Creecy A, Damrath JG, Wallace JM. Control of Bone Matrix Properties by Osteocytes. Front Endocrinol (Lausanne) 2020; 11:578477. [PMID: 33537002 PMCID: PMC7848033 DOI: 10.3389/fendo.2020.578477] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 12/01/2020] [Indexed: 12/13/2022] Open
Abstract
Osteocytes make up 90-95% of the cellular content of bone and form a rich dendritic network with a vastly greater surface area than either osteoblasts or osteoclasts. Osteocytes are well positioned to play a role in bone homeostasis by interacting directly with the matrix; however, the ability for these cells to modify bone matrix remains incompletely understood. With techniques for examining the nano- and microstructure of bone matrix components including hydroxyapatite and type I collagen becoming more widespread, there is great potential to uncover novel roles for the osteocyte in maintaining bone quality. In this review, we begin with an overview of osteocyte biology and the lacunar-canalicular system. Next, we describe recent findings from in vitro models of osteocytes, focusing on the transitions in cellular phenotype as they mature. Finally, we describe historical and current research on matrix alteration by osteocytes in vivo, focusing on the exciting potential for osteocytes to directly form, degrade, and modify the mineral and collagen in their surrounding matrix.
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Affiliation(s)
- Amy Creecy
- Department of Biomedical Engineering, Indiana University-Purdue University at Indianapolis, Indianapolis, IN, United States
| | - John G. Damrath
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Joseph M. Wallace
- Department of Biomedical Engineering, Indiana University-Purdue University at Indianapolis, Indianapolis, IN, United States
- *Correspondence: Joseph M. Wallace,
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27
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Abstract
Bone is the most frequent site of breast cancer and prostate cancer metastasis, and one of the most common sites of metastasis for many solid tumors. Once cancer cells colonize in the bone, it imposes a major clinical challenge for the treatment of the disease, and fatality rates increase drastically. Bone, the largest organ in the body, provides a fertile microenvironment enriched with nutrients, growth factors and hormones, a generous reward for cancer cells. Dependent on cancer type, cancer cells can cause osteoblastic (bone forming) or osteolytic lesions to promote the net resorption and/or release of growth factors from the bone extracellular matrix. These processes activate a "vicious cycle", leading to disruption of bone integrity and promoting cancer cell growth and migration. Cancer cells influence the bone microenvironment favoring their colonization and growth. In order to metastasize to the bone, cancer cells must first migrate from the site of origin, and once established within the bone, they must overcome the dormant inducing effects of resident cells. If successful, cancer cells can then colonize and continually disrupt bone homeostasis that is primarily maintained by osteocytes, the most abundant bone cell type. For example, it has been shown that exercise induces osteocytes to release anabolic factors that inhibit osteoclast resorptive activity, promote dormancy and the release of anti-cancer factors that inhibit breast cancer cell metastasis. In this review, we will summarize recent research findings and provide mechanistic insights related to the role of osteocytes in osteolytic metastasis.
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