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Shi V, Morgan EF. Estrogen and estrogen receptors mediate the mechanobiology of bone disease and repair. Bone 2024:117220. [PMID: 39106937 DOI: 10.1016/j.bone.2024.117220] [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: 06/08/2024] [Revised: 07/28/2024] [Accepted: 07/30/2024] [Indexed: 08/09/2024]
Abstract
It is well understood that the balance of bone formation and resorption is dependent on both mechanical and biochemical factors. In addition to cell-secreted cytokines and growth factors, sex hormones like estrogen are critical to maintaining bone health. Although the direct osteoprotective function of estrogen and estrogen receptors (ERs) has been reported extensively, evidence that estrogen signaling also has a role in mediating the effects of mechanical loading on maintenance of bone mass and healing of bone injuries has more recently emerged. Recent studies have underscored the role of estrogen and ERs in many pathways of bone mechanosensation and mechanotransduction. Estrogen and ERs have been shown to augment integrin-based mechanotransduction as well as canonical Wnt/b-catenin, RhoA/ROCK, and YAP/TAZ pathways. Estrogen and ERs also influence the mechanosensitivity of not only osteocytes but also osteoblasts, osteoclasts, and marrow stromal cells. The current review will highlight these roles of estrogen and ERs in cellular mechanisms underlying bone mechanobiology and discuss their implications for management of osteoporosis and bone fractures. A greater understanding of the mechanisms behind interactions between estrogen and mechanical loading may be crucial to addressing the shortcomings of current hormonal and pharmaceutical therapies. A combined therapy approach including high-impact exercise therapy may mitigate adverse side effects and allow an effective long-term solution for the prevention, treatment, and management of bone fragility in at-risk populations. Furthermore, future implications to novel local delivery mechanisms of hormonal therapy for osteoporosis treatment, as well as the effects on bone health of applications of sex hormone therapy outside of bone disease, will be discussed.
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Affiliation(s)
- Vivian Shi
- Boston University, Department of Biomedical Engineering, 44 Cummington St, Boston 02215, MA, USA; Center for Multiscale and Translational Mechanobiology, Boston University, 44 Cummington St, Boston 02215, MA, USA
| | - Elise F Morgan
- Boston University, Department of Biomedical Engineering, 44 Cummington St, Boston 02215, MA, USA; Center for Multiscale and Translational Mechanobiology, Boston University, 44 Cummington St, Boston 02215, MA, USA.
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2
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Ebrahim T, Ebrahim AS, Kandouz M. Diversity of Intercellular Communication Modes: A Cancer Biology Perspective. Cells 2024; 13:495. [PMID: 38534339 DOI: 10.3390/cells13060495] [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: 01/05/2024] [Revised: 02/27/2024] [Accepted: 03/10/2024] [Indexed: 03/28/2024] Open
Abstract
From the moment a cell is on the path to malignant transformation, its interaction with other cells from the microenvironment becomes altered. The flow of molecular information is at the heart of the cellular and systemic fate in tumors, and various processes participate in conveying key molecular information from or to certain cancer cells. For instance, the loss of tight junction molecules is part of the signal sent to cancer cells so that they are no longer bound to the primary tumors and are thus free to travel and metastasize. Upon the targeting of a single cell by a therapeutic drug, gap junctions are able to communicate death information to by-standing cells. The discovery of the importance of novel modes of cell-cell communication such as different types of extracellular vesicles or tunneling nanotubes is changing the way scientists look at these processes. However, are they all actively involved in different contexts at the same time or are they recruited to fulfill specific tasks? What does the multiplicity of modes mean for the overall progression of the disease? Here, we extend an open invitation to think about the overall significance of these questions, rather than engage in an elusive attempt at a systematic repertory of the mechanisms at play.
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Affiliation(s)
- Thanzeela Ebrahim
- Department of Pathology, Wayne State University School of Medicine, Detroit, MI 48202, USA
| | - Abdul Shukkur Ebrahim
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48202, USA
| | - Mustapha Kandouz
- Department of Pathology, Wayne State University School of Medicine, Detroit, MI 48202, USA
- Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48202, USA
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3
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Wang W, Zheng X, Wang H, Zuo B, Chen S, Li J. Mechanical Unloading Promotes Osteoclastic Differentiation and Bone Resorption by Modulating the MSC Secretome to Favor Inflammation. Cell Transplant 2024; 33:9636897241236584. [PMID: 38501500 PMCID: PMC10953070 DOI: 10.1177/09636897241236584] [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: 10/22/2023] [Revised: 02/11/2024] [Accepted: 02/13/2024] [Indexed: 03/20/2024] Open
Abstract
Aging, space flight, and prolonged bed rest have all been linked to bone loss, and no effective treatments are clinically available at present. Here, with the rodent hindlimb unloading (HU) model, we report that the bone marrow (BM) microenvironment was significantly altered, with an increased number of myeloid cells and elevated inflammatory cytokines. In such inflammatory BM, the osteoclast-mediated bone resorption was greatly enhanced, leading to a shifted bone remodeling balance that ultimately ends up with disuse-induced osteoporosis. Using Piezo1 conditional knockout (KO) mice (Piezo1fl/fl;LepRCre), we proved that lack of mechanical stimuli on LepR+ mesenchymal stem cells (MSCs) is the main reason for the pathological BM inflammation. Mechanically, the secretome of MSCs was regulated by mechanical stimuli. Inadequate mechanical load leads to increased production of inflammatory cytokines, such as interleukin (IL)-1α, IL-6, macrophage colony-stimulating factor 1 (M-CSF-1), and so on, which promotes monocyte proliferation and osteoclastic differentiation. Interestingly, transplantation of 10% cyclic mechanical stretch (CMS)-treated MSCs into HU animals significantly alleviated the BM microenvironment and rebalanced bone remodeling. In summary, our research revealed a new mechanism underlying mechanical unloading-induced bone loss and suggested a novel stem cell-based therapy to potentially prevent disuse-induced osteoporosis.
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Affiliation(s)
- Wanyuji Wang
- Department of Cell Biology, Zunyi Medical University, Zunyi, China
| | - Xueling Zheng
- Department of Cell Biology, Zunyi Medical University, Zunyi, China
| | - Hehe Wang
- Department of Cell Biology, Zunyi Medical University, Zunyi, China
| | - Bin Zuo
- Department of Orthopedic Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Sisi Chen
- Department of Orthopedic Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jiao Li
- Department of Cell Biology, Zunyi Medical University, Zunyi, China
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4
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Yu X, Dong M, Wang L, Yang Q, Wang L, Han W, Dong J, Liu T, Kong Y, Niu W. Nanotherapy for bone repair: milk-derived small extracellular vesicles delivery of icariin. Drug Deliv 2023; 30:2169414. [PMID: 36714914 PMCID: PMC9888478 DOI: 10.1080/10717544.2023.2169414] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Icariin (ICA) played an important role in the treatment of inflammatory bone defects. However, pharmacokinetic studies have shown that its poor bioavailability limited its application. In this context, we isolated bovine milk-derived sEV and prepared sEV-ICA to improve the osteogenic effect of ICA. In this study, we successfully constructed sEV-ICA. sEV-ICA was found to have significantly higher osteogenic efficiency than ICA in cell culture and cranial bone defect models. Mechanistically, bioinformatics analysis predicted that signal transducers and activators of transcription 5 (STAT5a) may bind to the GJA1 promoter, while luciferase activity assays and chromatin immunoprecipitation (ChIP) experiments confirmed that STAT5a directly binded to the GJA1 promoter to promote osteogenesis. We proved that compared with ICA, sEV-ICA showed a better effect of promoting bone repair in vivo and in vitro. In addition, sEV-ICA could promote osteogenesis by promoting the combination of STAT5a and GJA1 promoter. In summary, as a complex drug delivery system, sEV-ICA constituted a rapid and effective method for the treatment of bone defects and could improve the osteogenic activity of ICA.
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Affiliation(s)
- Xinxin Yu
- School of Stomatology, Dalian Medical University, Dalian, Liaoning, China
| | - Ming Dong
- School of Stomatology, Dalian Medical University, Dalian, Liaoning, China
| | - Lina Wang
- School of Stomatology, Dalian Medical University, Dalian, Liaoning, China
| | - Qian Yang
- School of Stomatology, Dalian Medical University, Dalian, Liaoning, China
| | - Long Wang
- School of Stomatology, Dalian Medical University, Dalian, Liaoning, China
| | - Wenqing Han
- School of Stomatology, Dalian Medical University, Dalian, Liaoning, China
| | - Juhong Dong
- School of Stomatology, Dalian Medical University, Dalian, Liaoning, China
| | - Tingjiao Liu
- Department of Basic Science of Stomatology, Shanghai Stomatological Hospital, Fudan University, Shanghai, China,Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Fudan University, Shanghai, China,Tingjiao Liu Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Fudan University, Shanghai200003, China; Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Fudan University, Shanghai200003, China
| | - Ying Kong
- Department Biochemistry and Molecular Biology, College of Basic Medical Sciences, Dalian Medical University, Dalian, Liaoning, China,Ying Kong Department Biochemistry and Molecular Biology, College of Basic Medical Sciences, Dalian Medical University, Dalian116044, Liaoning, China;
| | - Weidong Niu
- School of Stomatology, Dalian Medical University, Dalian, Liaoning, China,CONTACT Weidong Niu School of Stomatology, Dalian Medical University, Dalian116044, Liaoning, China;
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5
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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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Conformational changes in the human Cx43/GJA1 gap junction channel visualized using cryo-EM. Nat Commun 2023; 14:931. [PMID: 36805660 PMCID: PMC9938869 DOI: 10.1038/s41467-023-36593-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 02/07/2023] [Indexed: 02/20/2023] Open
Abstract
Connexin family proteins assemble into hexameric hemichannels in the cell membrane. The hemichannels dock together between two adjacent membranes to form gap junction intercellular channels (GJIChs). We report the cryo-electron microscopy structures of Cx43 GJICh, revealing the dynamic equilibrium state of various channel conformations in detergents and lipid nanodiscs. We identify three different N-terminal helix conformations of Cx43-gate-covering (GCN), pore-lining (PLN), and flexible intermediate (FIN)-that are randomly distributed in purified GJICh particles. The conformational equilibrium shifts to GCN by cholesteryl hemisuccinates and to PLN by C-terminal truncations and at varying pH. While GJIChs that mainly comprise GCN protomers are occluded by lipids, those containing conformationally heterogeneous protomers show markedly different pore sizes. We observe an α-to-π-helix transition in the first transmembrane helix, which creates a side opening to the membrane in the FIN and PLN conformations. This study provides basic structural information to understand the mechanisms of action and regulation of Cx43 GJICh.
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7
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Zeitz MJ, Smyth JW. Gap Junctions and Ageing. Subcell Biochem 2023; 102:113-137. [PMID: 36600132 DOI: 10.1007/978-3-031-21410-3_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Gap junctions, comprising connexin proteins, create conduits directly coupling the cytoplasms of adjacent cells. Expressed in essentially all tissues, dynamic gap junction structures enable the exchange of small molecules including ions and second messengers, and are central to maintenance of homeostasis and synchronized excitability. With such diverse and critical roles throughout the body, it is unsurprising that alterations to gap junction and/or connexin expression and function underlie a broad array of age-related pathologies. From neurological dysfunction to cardiac arrhythmia and bone loss, it is hard to identify a human disease state that does not involve reduced, or in some cases inappropriate, intercellular communication to affect organ function. With a complex life cycle encompassing several key regulatory steps, pathological gap junction remodeling during ageing can arise from alterations in gene expression, translation, intracellular trafficking, and posttranslational modification of connexins. Connexin proteins are now known to "moonlight" and perform a variety of non-junctional functions in the cell, independent of gap junctions. Furthermore, connexin "hemichannels" on the cell surface can communicate with the extracellular space without ever coupling to an adjacent cell to form a gap junction channel. This chapter will focus primarily on gap junctions in ageing, but such non-junctional connexin functions will be referred to where appropriate and the full spectrum of connexin biology should be noted as potentially causative/contributing to some findings in connexin knockout animals, for example.
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Affiliation(s)
- Michael J Zeitz
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA.,FBRI Center for Vascular and Heart Research, Roanoke, VA, USA
| | - James W Smyth
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA. .,FBRI Center for Vascular and Heart Research, Roanoke, VA, USA. .,Department of Biological Sciences, College of Science, Virginia Tech, Blacksburg, VA, USA. .,Department of Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA.
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8
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Zeng Y, Riquelme MA, Hua R, Zhang J, Acosta FM, Gu S, Jiang JX. Mechanosensitive piezo1 calcium channel activates connexin 43 hemichannels through PI3K signaling pathway in bone. Cell Biosci 2022; 12:191. [PMID: 36457052 PMCID: PMC9716748 DOI: 10.1186/s13578-022-00929-w] [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: 07/25/2022] [Accepted: 11/11/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Mechanical loading promotes bone formation and osteocytes are a major mechanosensory cell in the bone. Both Piezo1 channels and connexin 43 hemichannels (Cx43 HCs) in osteocytes are important players in mechanotransduction and anabolic function by mechanical loading. However, the mechanism underlying mechanotransduction involving Piezo1 channels and Cx43 HCs in osteocytes and bone remains unknown. RESULTS We showed that, like mechanical loading, Piezo1 specific agonist Yoda1 was able to increase intracellular Ca2+ signaling and activate Cx43 HCs, while Yoda1 antagonist Dooku1 inhibited Ca2+ and Cx43 HC activation induced by both mechanical loading and Yoda1. Moreover, the intracellular Ca2+ signal activated by Yoda1 was reduced by the inhibition of Cx43 HCs and pannexin1 (Panx1) channels, as well as ATP-P2X receptor signaling. Piezo1 and Cx43 HCs were co-localized on the osteocyte cell surface, and Yoda1-activated PI3K-Akt signaling regulated the opening of Cx43 HCs. Furthermore, Cx43 HCs opening by mechanical loading on tibias was ablated by inhibition of Piezo1 activation in vivo. CONCLUSION We demonstrated that upon mechanical stress, increased intracellular Ca2+ activated by Piezo1 regulates the opening of HCs through PI3K-Akt and opened Cx43 HCs, along with Panx1 channels, and ATP-P2X signaling sustain the intracellular Ca2+ signal, leading to bone anabolic function.
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Affiliation(s)
- Yan Zeng
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA ,grid.452708.c0000 0004 1803 0208The Second Xiangya Hospital, Central South University, Changsha, Hunan China
| | - Manuel A. Riquelme
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
| | - Rui Hua
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
| | - Jingruo Zhang
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
| | - Francisca M. Acosta
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
| | - Sumin Gu
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
| | - Jean X. Jiang
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
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IL-6 is involved in thoracic ossification of the ligamentum flavum. PLoS One 2022; 17:e0272357. [PMID: 35905126 PMCID: PMC9337630 DOI: 10.1371/journal.pone.0272357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 07/18/2022] [Indexed: 11/19/2022] Open
Abstract
Thoracic ossification of the ligamentum flavum (TOLF) is a heterotopic ossification of spinal ligaments. TOLF is the major cause of thoracic spinal canal stenosis and myelopathy, and its underlying mechanisms are not clear. Bone formation is a complex developmental process involving the differentiation of mesenchymal stem cells to osteoblasts, and regulated by BMP2, RUNX2, Osterix (OSX), etc. In this study, we continue to further characterize properties of TOLF. Our immunohistochemistry experiments showed that expressions of osteoblastic factors such as BMP2 and RUNX2 increased in TOLF. According to flow cytometry analysis the proportion of S phase of cell cycle in primary TOLF cells was 9% higher than the control. Alizarin red staining and ALP staining observations were consistent with immunohistochemistry results. It was also observed that inflammatory cytokine IL-6 level dramatically increased in the culture supernatant of primary TOLF cells. We propose the hypothesis that IL-6 is involved in TOLF. To testify the hypothesis, we examined the effect of IL-6. Our results showed that IL-6 was able to activate expressions of osteoblastic factors such as BMP2, RUNX2, OSX, OCN and ALP, and that expressions of cell proliferation factors cyclin D1 and cyclin C increased in the presence of IL-6. Moreover, IL-6-induced BMP2 expression was inhibited by p38 inhibitor SB203580, indicating that IL-6 regulated the osteogenic BMP2 activation through p38 MAPK pathway. These data suggest that IL-6 is involved in TOLF.
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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: 98] [Impact Index Per Article: 49.0] [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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Spasic M, Duffy MP, Jacobs CR. Fenoldopam Sensitizes Primary Cilia-Mediated Mechanosensing to Promote Osteogenic Intercellular Signaling and Whole Bone Adaptation. J Bone Miner Res 2022; 37:972-982. [PMID: 35230705 PMCID: PMC9098671 DOI: 10.1002/jbmr.4536] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 02/01/2022] [Accepted: 02/12/2022] [Indexed: 11/05/2022]
Abstract
Bone cells actively respond to mechanical stimuli to direct bone formation, yet there is no current treatment strategy for conditions of low bone mass and osteoporosis designed to target the inherent mechanosensitivity of bone. Our group has previously identified the primary cilium as a critical mechanosensor within bone, and that pharmacologically targeting the primary cilium with fenoldopam can enhance osteocyte mechanosensitivity. Here, we demonstrate that potentiating osteocyte mechanosensing with fenoldopam in vitro promotes pro-osteogenic paracrine signaling to osteoblasts. Conversely, impairing primary cilia formation and the function of key ciliary mechanotransduction proteins attenuates this intercellular signaling cascade. We then utilize an in vivo model of load-induced bone formation to demonstrate that fenoldopam treatment sensitizes bones of both healthy and osteoporotic mice to mechanical stimulation. Furthermore, we show minimal adverse effects of this treatment and demonstrate that prolonged treatment biases trabecular bone adaptation. This work is the first to examine the efficacy of targeting primary cilia-mediated mechanosensing to enhance bone formation in osteoporotic animals. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Milos Spasic
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Michael P Duffy
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
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12
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Liu Y, Duan M, Guo D, Kan S, Zhang L, Aili M, Zhang D, Du W, Xie J. PDGF-AA promotes cell-to-cell communication in osteocytes through PI3K/Akt signaling pathway. Acta Biochim Biophys Sin (Shanghai) 2021; 53:1640-1649. [PMID: 34586354 DOI: 10.1093/abbs/gmab136] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/24/2021] [Accepted: 09/23/2021] [Indexed: 02/05/2023] Open
Abstract
Osteocytes are the main sensitive cells in bone remodeling due to their potent functional cell processes from the mineralized bone matrix to the bone surface and the bone marrow. Neighboring osteocytes communicate with each other by these cell processes to achieve molecular exchange through gap junction channels. Platelet-derived growth factor-AA (PDGF-AA) has been reported to enhance bone tissue remodeling by promoting cell proliferation, migration, and autocrine secretion in osteoid cell linage. However, the effect of PDGF-AA on intercellular communication between osteocytes is still unclear. In the present study, we elucidated that PDGF-AA could enhance the formation of dendritic processes of osteocytes and the gap junctional intercellular communication by promoting the expression of connexin43 (Cx43). This modulation process was mainly dependent on the activation of phosphorylation of Akt protein by phosphatidylinositol 3-kinase (PI3K)/Akt (also known as protein kinase B, PKB) signaling. Inhibition of PI3K/Akt signaling decreased the Cx43 expression induced by PDGF-AA. These results establish a bridge between PDGF-AA and cell-cell communication in osteocytes, which could help us understand the molecular exchange between bone cells and fracture healing.
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Affiliation(s)
- Yang Liu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Mengmeng Duan
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Daimo Guo
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Shiyi Kan
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Li Zhang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Munire Aili
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Demao Zhang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Wei Du
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
- National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
- Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Jing Xie
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
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13
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Moharrer Y, Boerckel JD. Tunnels in the rock: Dynamics of osteocyte morphogenesis. Bone 2021; 153:116104. [PMID: 34245936 PMCID: PMC8478866 DOI: 10.1016/j.bone.2021.116104] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 06/11/2021] [Accepted: 06/28/2021] [Indexed: 11/27/2022]
Abstract
Osteocytes are dynamic, bone matrix-remodeling cells that form an intricate network of interconnected projections through the bone matrix, called the lacunar-canalicular system. Osteocytes are the dominant mechanosensory cells in bone and their mechanosensory and mechanotransductive functions follow their morphological form. During osteocytogenesis and development of the osteocyte lacunar-canalicular network, osteocytes must dramatically remodel both their cytoskeleton and their extracellular matrix. In this review, we summarize our current understanding of the mechanisms that govern osteocyte differentiation, cytoskeletal morphogenesis, mechanotransduction, and matrix remodeling. We postulate that the physiologic activation of matrix remodeling in adult osteocytes, known as perilacunar/canalicular remodeling (PLR) represents a re-activation of the developmental program by which the osteocyte network is first established. While much of osteocyte biology remains unclear, new tools and approaches make the present moment a particularly fruitful and exciting time to study the development of these remarkable cells.
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Affiliation(s)
- Yasaman Moharrer
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States of America; Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Joel D Boerckel
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States of America; Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, United States of America; Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States of America.
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14
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The mechanosensory and mechanotransductive processes mediated by ion channels and the impact on bone metabolism: A systematic review. Arch Biochem Biophys 2021; 711:109020. [PMID: 34461086 DOI: 10.1016/j.abb.2021.109020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 02/06/2023]
Abstract
Mechanical environments were associated with alterations in bone metabolism. Ion channels present on bone cells are indispensable for bone metabolism and can be directly or indirectly activated by mechanical stimulation. This review aimed to discuss the literature reporting the mechanical regulatory effects of ion channels on bone cells and bone tissue. An electronic search was conducted in PubMed, Embase and Web of Science. Studies about mechanically induced alteration of bone cells and bone tissue by ion channels were included. Ion channels including TRP family channels, Ca2+ release-activated Ca2+ channels (CRACs), Piezo1/2 channels, purinergic receptors, NMDA receptors, voltage-sensitive calcium channels (VSCCs), TREK2 potassium channels, calcium- and voltage-dependent big conductance potassium (BKCa) channels, small conductance, calcium-activated potassium (SKCa) channels and epithelial sodium channels (ENaCs) present on bone cells and bone tissue participate in the mechanical regulation of bone development in addition to contributing to direct or indirect mechanotransduction such as altered membrane potential and ionic flux. Physiological (beneficial) mechanical stimulation could induce the anabolism of bone cells and bone tissue through ion channels, but abnormal (harmful) mechanical stimulation could also induce the catabolism of bone cells and bone tissue through ion channels. Functional expression of ion channels is vital for the mechanotransduction of bone cells. Mechanical activation (opening) of ion channels triggers ion influx and induces the activation of intracellular modulators that can influence bone metabolism. Therefore, mechanosensitive ion channels provide new insights into therapeutic targets for the treatment of bone-related diseases such as osteopenia and aseptic implant loosening.
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15
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Yamamoto T, Hasegawa T, Fraitas PHLD, Hongo H, Zhao S, Yamamoto T, Nasoori A, Abe M, Maruoka H, Kubota K, Morimoto Y, Haraguchi M, Shimizu T, Takahata M, Iwasaki N, Li M, Amizuka N. Histochemical characteristics on minimodeling-based bone formation induced by anabolic drugs for osteoporotic treatment. Biomed Res 2021; 42:161-171. [PMID: 34544992 DOI: 10.2220/biomedres.42.161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Modeling, the changes of bone size and shape, often takes place at the developmental stages, whereas bone remodeling-replacing old bone with new bone-predominantly occurs in adults. Unlike bone remodeling, bone formation induced by modeling i.e., minimodeling (microscopic modeling in cancellous bone) is independent of osteoclastic bone resorption. Although recently-developed drugs for osteoporotic treatment could induce minimodeling-based bone formation in addition to remodeling-based bone formation, few reports have demonstrated the histological aspects of minimodeling-based bone formation. After administration of eldecalcitol or romosozumab, unlike teriparatide treatment, mature osteoblasts formed new bone by minimodeling, without developing thick preosteoblastic layers. The histological characteristics of minimodeling-based bone formation is quite different from remodeling, as it is not related to osteoclastic bone resorption, resulting in convex-shaped new bone and smooth cement lines called arrest lines. In this review, we will show histological properties of minimodeling-based bone formation by osteoporotic drugs.
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Affiliation(s)
- Tomomaya Yamamoto
- Developmental Biology of Hard Tissue, Graduate School of Dental Medicine, and Faculty of Dental Medicine, Hokkaido University.,Northern Army Medical Unit, Camp Makomanai, Japan Ground Self-Defense Forces
| | - Tomoka Hasegawa
- Developmental Biology of Hard Tissue, Graduate School of Dental Medicine, and Faculty of Dental Medicine, Hokkaido University
| | | | - Hiromi Hongo
- Developmental Biology of Hard Tissue, Graduate School of Dental Medicine, and Faculty of Dental Medicine, Hokkaido University
| | - Shen Zhao
- National Clinical Research Center of Stomatology, Department of Endodontics, School of Medicine, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Ninth People's Hospital, Shanghai Jiaotong University
| | - Tsuneyuki Yamamoto
- Oral Functional Anatomy, Graduate School of Dental Medicine, and Faculty of Dental Medicine, Hokkaido University
| | - Alireza Nasoori
- Developmental Biology of Hard Tissue, Graduate School of Dental Medicine, and Faculty of Dental Medicine, Hokkaido University
| | - Miki Abe
- Developmental Biology of Hard Tissue, Graduate School of Dental Medicine, and Faculty of Dental Medicine, Hokkaido University
| | - Haruhi Maruoka
- Orthodontics, Graduate School of Dental Medicine, and Faculty of Dental Medicine, Hokkaido University
| | - Keisuke Kubota
- Oral Functional Prosthodontics, Graduate School of Dental Medicine, and Faculty of Dental Medicine, Hokkaido University
| | - Yasuhito Morimoto
- Periodontology and Endodontology, Graduate School of Dental Medicine, and Faculty of Dental Medicine, Hokkaido University
| | - Mai Haraguchi
- Developmental Biology of Hard Tissue, Graduate School of Dental Medicine, and Faculty of Dental Medicine, Hokkaido University
| | - Tomohiro Shimizu
- Department of Orthopedic Surgery, Graduate School of Dental Medicine, and Faculty of Dental Medicine, Hokkaido University
| | - Masahiko Takahata
- Department of Orthopedic Surgery, Graduate School of Dental Medicine, and Faculty of Dental Medicine, Hokkaido University
| | - Norimasa Iwasaki
- Department of Orthopedic Surgery, Graduate School of Dental Medicine, and Faculty of Dental Medicine, Hokkaido University
| | - Minqi Li
- Shandong Provincial Key Laboratory of Oral Biomedicine, The School of Stomatology, Shandong University
| | - Norio Amizuka
- Developmental Biology of Hard Tissue, Graduate School of Dental Medicine, and Faculty of Dental Medicine, Hokkaido University
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16
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Gould NR, Torre OM, Leser JM, Stains JP. The cytoskeleton and connected elements in bone cell mechano-transduction. Bone 2021; 149:115971. [PMID: 33892173 PMCID: PMC8217329 DOI: 10.1016/j.bone.2021.115971] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/30/2021] [Accepted: 04/17/2021] [Indexed: 02/07/2023]
Abstract
Bone is a mechano-responsive tissue that adapts to changes in its mechanical environment. Increases in strain lead to increased bone mass acquisition, whereas decreases in strain lead to a loss of bone mass. Given that mechanical stress is a regulator of bone mass and quality, it is important to understand how bone cells sense and transduce these mechanical cues into biological changes to identify druggable targets that can be exploited to restore bone cell mechano-sensitivity or to mimic mechanical load. Many studies have identified individual cytoskeletal components - microtubules, actin, and intermediate filaments - as mechano-sensors in bone. However, given the high interconnectedness and interaction between individual cytoskeletal components, and that they can assemble into multiple discreet cellular structures, it is likely that the cytoskeleton as a whole, rather than one specific component, is necessary for proper bone cell mechano-transduction. This review will examine the role of each cytoskeletal element in bone cell mechano-transduction and will present a unified view of how these elements interact and work together to create a mechano-sensor that is necessary to control bone formation following mechanical stress.
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Affiliation(s)
- Nicole R Gould
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Olivia M Torre
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jenna M Leser
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Joseph P Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA..
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17
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Jewlal E, Barr K, Laird DW, Willmore KE. Connexin 43 contributes to phenotypic robustness of the mouse skull. Dev Dyn 2021; 250:1810-1827. [PMID: 34091987 DOI: 10.1002/dvdy.381] [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: 03/26/2021] [Revised: 05/13/2021] [Accepted: 06/02/2021] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND We compared skull shape and variation among genetically modified mice that exhibit different levels of connexin43 (Cx43) channel function, to determine whether Cx43 contributes to craniofacial phenotypic robustness. Specifically, we used two heterozygous mutant mouse models (G60S/+ and I130T/+) that, when compared to their wildtype counterparts, have an ~80% and ~50% reduction in Cx43 function, respectively. RESULTS Both mutant strains showed significant differences in skull shape compared to wildtype littermates and while these differences were more severe in the G60S/+ mouse, shape differences were localized to similar regions of the skull in both mutants. However, increased skull shape variation was observed in G60S/+ mutants only. Additionally, covariation of skull structures was disrupted in the G60S/+ mutants only, indicating that while a 50% reduction in Cx43 function is sufficient to cause a shift in mean skull shape, the threshold for Cx43 function for disrupting craniofacial phenotypic robustness is lower. CONCLUSIONS Collectively, our results indicate Cx43 can contribute to phenotypic robustness of the skull through a nonlinear relationship between Cx43 gap junctional function and phenotypic outcomes.
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Affiliation(s)
- Elizabeth Jewlal
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Kevin Barr
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Dale W Laird
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada.,Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Katherine E Willmore
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
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18
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Adhikari M, Delgado-Calle J. Role of Osteocytes in Cancer Progression in the Bone and the Associated Skeletal Disease. Curr Osteoporos Rep 2021; 19:247-255. [PMID: 33818732 PMCID: PMC8486016 DOI: 10.1007/s11914-021-00679-7] [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: 03/17/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE OF REVIEW The goal of this manuscript is to review the current knowledge on the role of osteocytes in cancer in the bone, discuss the potential of osteocytes as a therapeutic target, and propose future research needed to understand the crosstalk between cancer cells and osteocytes in the tumor niche. RECENT FINDINGS Numerous studies have established that cancer cells manipulate osteocytes to facilitate invasion and tumor progression in bone. Moreover, cancer cells dysregulate osteocyte function to disrupt physiological bone remodeling, leading to the development of bone disease. Targeting osteocytes and their derived factors has proven to effectively interfere with the progression of cancer in the bone and the associated bone disease. Osteocytes communicate with cancer cells and are also part of the vicious cycle of cancer in the bone. Additional studies investigating the role of osteocytes on metastases to the bone and the development of drug resistance are needed.
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Affiliation(s)
- Manish Adhikari
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Jesús Delgado-Calle
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA.
- Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA.
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19
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Lira Dos Santos EJ, Salmon CR, Chavez MB, de Almeida AB, Tan MH, Chu EY, Sallum EA, Casati MZ, Ruiz KGS, Kantovitz KR, Foster BL, Nociti Júnior FH. Cementocyte alterations associated with experimentally induced cellular cementum apposition in hyp mice. J Periodontol 2021; 92:116-127. [PMID: 34003518 DOI: 10.1002/jper.21-0119] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 05/10/2021] [Accepted: 05/10/2021] [Indexed: 02/05/2023]
Abstract
BACKGROUND Cellular cementum, a mineralized tissue covering apical tooth roots, grows by apposition to maintain the tooth in its occlusal position. We hypothesized that resident cementocytes would show morphological changes in response to cementum apposition, possibly implicating a role in cementum biology. METHODS Mandibular first molars were induced to super-erupt (EIA) by extraction of maxillary molars, promoting rapid new cementum formation. Tissue and cell responses were analyzed at 6 and/or 21 days post-procedure (dpp). RESULTS High-resolution micro-computed tomography (micro-CT) and confocal laser scanning microscopy showed increased cellular cementum by 21 dpp. Transmission electron microscopy (TEM) revealed that cementocytes under EIA were 50% larger than control cells, supported by larger pore sizes detected by micro-CT. Cementocytes under EIA displayed ultrastructural changes consistent with increased activity, including increased cytoplasm and nuclear size. We applied EIA to Hyp mutant mice, where cementocytes have perilacunar hypomineralization defects, to test cell and tissue responses in an altered mechanoresponsive milieu. Hyp and WT molars displayed similar super-eruption, with Hyp molars exhibiting 28% increased cellular cementum area versus 22% in WT mice at 21 dpp. Compared to control, Hyp cementocytes featured well-defined, disperse euchromatin and a thick layer of peripherally condensed heterochromatin in nuclei, indicating cellular activity. Immunohistochemistry (IHC) for cementum markers revealed intense dentin matrix protein-1 expression and abnormal osteopontin deposition in Hyp mice. Both WT and Hyp cementocytes expressed gap junction protein, connexin 43. CONCLUSION This study provides new insights into the EIA model and cementocyte activity in association with new cementum formation.
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Affiliation(s)
- Elis J Lira Dos Santos
- Department of Prosthodontics and Periodontics, Division of Periodontics, Piracicaba Dental School, State University of Campinas, São Paulo, Brazil
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH
| | - Cristiane R Salmon
- Department of Prosthodontics and Periodontics, Division of Periodontics, Piracicaba Dental School, State University of Campinas, São Paulo, Brazil
- Faculty of Dentistry, N. Sra. do Patrocínio University Center, Itu, São Paulo, Brazil
| | - Michael B Chavez
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH
| | - Amanda B de Almeida
- Department of Prosthodontics and Periodontics, Division of Periodontics, Piracicaba Dental School, State University of Campinas, São Paulo, Brazil
| | - Michelle H Tan
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH
| | - Emily Y Chu
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD
| | - Enilson A Sallum
- Department of Prosthodontics and Periodontics, Division of Periodontics, Piracicaba Dental School, State University of Campinas, São Paulo, Brazil
| | - Marcio Z Casati
- Department of Prosthodontics and Periodontics, Division of Periodontics, Piracicaba Dental School, State University of Campinas, São Paulo, Brazil
| | - Karina G S Ruiz
- Department of Prosthodontics and Periodontics, Division of Periodontics, Piracicaba Dental School, State University of Campinas, São Paulo, Brazil
| | - Kamila R Kantovitz
- Department of Dental Materials, São Leopoldo Mandic Research Center, Campinas, São Paulo, Brazil
| | - Brian L Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH
| | - Francisco H Nociti Júnior
- Department of Prosthodontics and Periodontics, Division of Periodontics, Piracicaba Dental School, State University of Campinas, São Paulo, Brazil
- São Leopoldo Mandic Research Center, Campinas, São Paulo, Brazil
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20
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Li MCM, Chow SKH, Wong RMY, Qin L, Cheung WH. The role of osteocytes-specific molecular mechanism in regulation of mechanotransduction - A systematic review. J Orthop Translat 2021; 29:1-9. [PMID: 34036041 PMCID: PMC8138679 DOI: 10.1016/j.jot.2021.04.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/15/2021] [Accepted: 04/11/2021] [Indexed: 11/29/2022] Open
Abstract
Background Osteocytes, composing over 90% of bone cells, are well known for their mechanosensing abilities. Aged osteocytes with impaired morphology and function are less efficient in mechanotransduction which will disrupt bone turnover leading to osteoporosis. The aim of this systematic review is to delineate the mechanotransduction mechanism at different stages in order to explore potential target for therapeutic drugs. Methods A systematic literature search was performed in PubMed and Web of Science. Original animal, cell and clinical studies with available English full-text were included. Information was extracted from the included studies for review. Results The 26 studies included in this review provided evidence that mechanical loading are sensed by osteocytes via various sensing proteins and transduced to different signaling molecules which later initiate various biochemical responses. Studies have shown that osteocyte plasma membrane and cytoskeletons are emerging key players in initiating mechanotransduction. Bone regulating genes expressions are altered in response to load sensed by osteocytes, but the genes involved different signaling pathways and the spatiotemporal expression pattern had made mechanotransduction mechanism complicated. Most of the included studies described the important role of osteocytes in pathways that regulate mechanosensing and bone remodeling. Conclusions This systematic review provides an up-to-date insight to different steps of mechanotransduction. A better understanding of the mechanotransduction mechanism is beneficial in search of new potential treatment for osteoporotic patients. By delineating the unique morphology of osteocytes and their interconnected signaling network new targets can be discovered for drug development. Translational potential of this article This systematic review provides an up-to-date sequential overview and highlights the different osteocyte-related pathways and signaling molecules during mechanotransduction. This allows a better understanding of mechanotransduction for future development of new therapeutic interventions to treat patients with impaired mechanosensitivity.
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Affiliation(s)
- Meng Chen Michelle Li
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
| | - Simon Kwoon Ho Chow
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
- The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, PR China
| | - Ronald Man Yeung Wong
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
| | - Ling Qin
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
| | - Wing Hoi Cheung
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
- The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, PR China
- Corresponding author.Department of Orthopaedics and Traumatology, 5/F, Clinical Sciences Building, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
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21
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Kong Q, Quan Y, Tian G, Zhou J, Liu X. Purinergic P2 Receptors: Novel Mediators of Mechanotransduction. Front Pharmacol 2021; 12:671809. [PMID: 34025431 PMCID: PMC8138185 DOI: 10.3389/fphar.2021.671809] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 04/26/2021] [Indexed: 02/05/2023] Open
Abstract
Mechanosensing and mechanotransduction are vital processes in mechanobiology and play critical roles in regulating cellular behavior and fate. There is increasing evidence that purinergic P2 receptors, members of the purinergic family, play a crucial role in cellular mechanotransduction. Thus, information on the specific mechanism of P2 receptor-mediated mechanotransduction would be valuable. In this review, we focus on purinergic P2 receptor signaling pathways and describe in detail the interaction of P2 receptors with other mechanosensitive molecules, including transient receptor potential channels, integrins, caveolae-associated proteins and hemichannels. In addition, we review the activation of purinergic P2 receptors and the role of various P2 receptors in the regulation of various pathophysiological processes induced by mechanical stimuli.
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Affiliation(s)
- Qihang Kong
- Laboratory of Cardiovascular Diseases, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, China
| | - Yue Quan
- Laboratory of Cardiovascular Diseases, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, China
| | - Geer Tian
- Laboratory of Cardiovascular Diseases, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, China
| | - Junteng Zhou
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaojing Liu
- Laboratory of Cardiovascular Diseases, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, China.,Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China
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22
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Zou ML, Chen ZH, Teng YY, Liu SY, Jia Y, Zhang KW, Sun ZL, Wu JJ, Yuan ZD, Feng Y, Li X, Xu RS, Yuan FL. The Smad Dependent TGF-β and BMP Signaling Pathway in Bone Remodeling and Therapies. Front Mol Biosci 2021; 8:593310. [PMID: 34026818 PMCID: PMC8131681 DOI: 10.3389/fmolb.2021.593310] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 04/23/2021] [Indexed: 12/15/2022] Open
Abstract
Bone remodeling is a continuous process that maintains the homeostasis of the skeletal system, and it depends on the homeostasis between bone-forming osteoblasts and bone-absorbing osteoclasts. A large number of studies have confirmed that the Smad signaling pathway is essential for the regulation of osteoblastic and osteoclastic differentiation during skeletal development, bone formation and bone homeostasis, suggesting a close relationship between Smad signaling and bone remodeling. It is known that Smads proteins are pivotal intracellular effectors for the members of the transforming growth factor-β (TGF-β) and bone morphogenetic proteins (BMP), acting as transcription factors. Smad mediates the signal transduction in TGF-β and BMP signaling pathway that affects both osteoblast and osteoclast functions, and therefore plays a critical role in the regulation of bone remodeling. Increasing studies have demonstrated that a number of Smad signaling regulators have potential functions in bone remodeling. Therefore, targeting Smad dependent TGF-β and BMP signaling pathway might be a novel and promising therapeutic strategy against osteoporosis. This article aims to review recent advances in this field, summarizing the influence of Smad on osteoblast and osteoclast function, together with Smad signaling regulators in bone remodeling. This will facilitate the understanding of Smad signaling pathway in bone biology and shed new light on the modulation and potential treatment for osteoporosis.
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Affiliation(s)
- Ming-Li Zou
- Wuxi Clinical Medicine School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Wuxi, China.,Institute of Integrated Chinese and Western Medicine, The Hospital Affiliated to Jiangnan University, Wuxi, China
| | - Zhong-Hua Chen
- Institute of Integrated Chinese and Western Medicine, The Third Hospital Affiliated to Nantong University, Wuxi, China
| | - Ying-Ying Teng
- Institute of Integrated Chinese and Western Medicine, The Hospital Affiliated to Jiangnan University, Wuxi, China
| | - Si-Yu Liu
- Wuxi Clinical Medicine School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Wuxi, China.,Institute of Integrated Chinese and Western Medicine, The Hospital Affiliated to Jiangnan University, Wuxi, China
| | - Yuan Jia
- Wuxi Clinical Medicine School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Wuxi, China.,Institute of Integrated Chinese and Western Medicine, The Hospital Affiliated to Jiangnan University, Wuxi, China
| | - Kai-Wen Zhang
- Wuxi Clinical Medicine School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Wuxi, China.,Institute of Integrated Chinese and Western Medicine, The Hospital Affiliated to Jiangnan University, Wuxi, China
| | - Zi-Li Sun
- Wuxi Clinical Medicine School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Wuxi, China.,Institute of Integrated Chinese and Western Medicine, The Hospital Affiliated to Jiangnan University, Wuxi, China
| | - Jun-Jie Wu
- Institute of Integrated Chinese and Western Medicine, The Hospital Affiliated to Jiangnan University, Wuxi, China
| | - Zheng-Dong Yuan
- Institute of Integrated Chinese and Western Medicine, The Hospital Affiliated to Jiangnan University, Wuxi, China
| | - Yi Feng
- Institute of Integrated Chinese and Western Medicine, The Hospital Affiliated to Jiangnan University, Wuxi, China
| | - Xia Li
- Institute of Integrated Chinese and Western Medicine, The Hospital Affiliated to Jiangnan University, Wuxi, China
| | - Rui-Sheng Xu
- Institute of Integrated Chinese and Western Medicine, The Hospital Affiliated to Jiangnan University, Wuxi, China
| | - Feng-Lai Yuan
- Institute of Integrated Chinese and Western Medicine, The Hospital Affiliated to Jiangnan University, Wuxi, China
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23
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Li D, Li L, Chen X, Zhou C, Hao B, Cao Y. Dysregulation of lncRNA-CCRR contributes to brain metastasis of breast cancer by intercellular coupling via regulating connexin 43 expression. J Cell Mol Med 2021; 25:4826-4834. [PMID: 33793070 PMCID: PMC8107087 DOI: 10.1111/jcmm.16455] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 02/19/2021] [Accepted: 03/01/2021] [Indexed: 01/05/2023] Open
Abstract
Cardiac conduction regulatory RNA (CCRR) is down‐regulated in the pathogenesis of heart failure (HF), which accordingly suppresses cardiac conduction while promoting arrhythmogenicity. Meanwhile, CX43 was reported to play a role in the pathogenesis of metastatic breast cancer and melanoma brain colonization. In this study, we studied the role of long non‐coding RNA CCRR and its interaction with CX43 in brain metastasis of breast cancer. Breast cancer patients were grouped according to the metastasis status. Real‐time PCR and IHC assay were used to measure the expression of lncRNA‐CCRR and CX43 in patients. Western blot was conducted to observe the effect of lncRNA‐CCRR on the expression of CX43 in MDA‐MB‐231BR and BT‐474BR cells. Compared with the non‐metastasis group, the mRNA expression of tissue lncRNA‐CCRR, cerebrospinal fluid (CSF) lncRNA‐CCRR, tissue CX43 and tissue protein expression of CX43 were both evidently up‐regulated in metastasis patients, especially in patients with brain metastasis. The expression of lncRNA‐CCRR was positively correlated with the up‐regulated expression of CX43. Moreover, CX43 expression was significantly lower in MDA‐MB‐231WT cells compared with that in MDA‐MB‐231BR cells. Also, the overexpression of lncRNA‐CCRR evidently increased dye transfer rate from astrocytes to MDA‐MB‐231BR/BT‐474BR cells but reduced lncRNA‐CCRR expression and suppressed the transmigration of MDA‐MB‐231BR/BT‐474BR cells in a blood‐brain barrier (BBB) model. In this study, we demonstrated that the presence of lncRNA‐CCRR could up‐regulate the expression of CX43, which promoted gap junction formation in brain metastasis of breast cancer. Accordingly, the communication between breast cancer cells and astrocytes was also promoted.
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Affiliation(s)
- Deheng Li
- Department of Neurosurgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Liangdong Li
- Department of Neurosurgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xin Chen
- Department of Neurosurgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Changshuai Zhou
- Department of Neurosurgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Bin Hao
- Department of Neurosurgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yiqun Cao
- Department of Neurosurgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
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24
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Costa V, De Fine M, Carina V, Conigliaro A, Raimondi L, De Luca A, Bellavia D, Salamanna F, Alessandro R, Pignatti G, Fini M, Giavaresi G. How miR-31-5p and miR-33a-5p Regulates SP1/CX43 Expression in Osteoarthritis Disease: Preliminary Insights. Int J Mol Sci 2021; 22:2471. [PMID: 33671114 PMCID: PMC7957523 DOI: 10.3390/ijms22052471] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/24/2021] [Accepted: 02/24/2021] [Indexed: 12/24/2022] Open
Abstract
Osteoarthritis (OA) is a degenerative bone disease that involved micro and macro-environment of joints. To date, there are no radical curative treatments for OA and novel therapies are mandatory. Recent evidence suggests the role of miRNAs in OA progression. In our previous studies, we demonstrated the role of miR-31-5p and miR-33a families in different bone regeneration signaling. Here, we investigated the role of miR-31-5p and miR-33a-5p in OA progression. A different expression of miR-31-5p and miR-33a-5p into osteoblasts and chondrocytes isolated from joint tissues of OA patients classified in based on different Kellgren and Lawrence (KL) grading was highlighted; and through a bioinformatic approach the common miRNAs target Specificity proteins (Sp1) were identified. Sp1 regulates the expression of gap junction protein Connexin43 (Cx43), which in OA drives the modification of i) osteoblasts and chondrocytes genes expression, ii) joint inflammation cytokines releases and iii) cell functions. Concerning this, thanks to gain and loss of function studies, the possible role of Sp1 as a modulator of CX43 expression through miR-31-5p and miR-33a-5p action was also evaluated. Finally, we hypothesize that both miRNAs cooperate to modulate the expression of SP1 in osteoblasts and chondrocytes and interfering, consequently, with CX43 expression, and they might be further investigated as new possible biomarkers for OA.
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Affiliation(s)
- Viviana Costa
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
| | - Marcello De Fine
- IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (M.D.F.); (G.P.)
| | - Valeria Carina
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
| | - Alice Conigliaro
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Section of Biology and Genetics, University of Palermo, 90133 Palermo, Italy; (A.C.); (R.A.)
| | - Lavinia Raimondi
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
| | - Angela De Luca
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
| | - Daniele Bellavia
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
| | - Francesca Salamanna
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
| | - Riccardo Alessandro
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Section of Biology and Genetics, University of Palermo, 90133 Palermo, Italy; (A.C.); (R.A.)
- Istituto per la Ricerca e l’Innovazione Biomedica (IRIB), 90133 Palermo, Italy
| | - Giovanni Pignatti
- IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (M.D.F.); (G.P.)
| | - Milena Fini
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
| | - Gianluca Giavaresi
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
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25
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Strauss RE, Gourdie RG. Cx43 and the Actin Cytoskeleton: Novel Roles and Implications for Cell-Cell Junction-Based Barrier Function Regulation. Biomolecules 2020; 10:E1656. [PMID: 33321985 PMCID: PMC7764618 DOI: 10.3390/biom10121656] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/07/2020] [Accepted: 12/07/2020] [Indexed: 12/13/2022] Open
Abstract
Barrier function is a vital homeostatic mechanism employed by epithelial and endothelial tissue. Diseases across a wide range of tissue types involve dynamic changes in transcellular junctional complexes and the actin cytoskeleton in the regulation of substance exchange across tissue compartments. In this review, we focus on the contribution of the gap junction protein, Cx43, to the biophysical and biochemical regulation of barrier function. First, we introduce the structure and canonical channel-dependent functions of Cx43. Second, we define barrier function and examine the key molecular structures fundamental to its regulation. Third, we survey the literature on the channel-dependent roles of connexins in barrier function, with an emphasis on the role of Cx43 and the actin cytoskeleton. Lastly, we discuss findings on the channel-independent roles of Cx43 in its associations with the actin cytoskeleton and focal adhesion structures highlighted by PI3K signaling, in the potential modulation of cellular barriers. Mounting evidence of crosstalk between connexins, the cytoskeleton, focal adhesion complexes, and junctional structures has led to a growing appreciation of how barrier-modulating mechanisms may work together to effect solute and cellular flux across tissue boundaries. This new understanding could translate into improved therapeutic outcomes in the treatment of barrier-associated diseases.
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Affiliation(s)
- Randy E. Strauss
- Virginia Tech, Translational Biology Medicine and Health (TBMH) Program, Roanoke, VA 24016, USA
| | - Robert G. Gourdie
- Center for Heart and Reparative Medicine Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
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26
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Moore AC, Wu J, Jewlal E, Barr K, Laird DW, Willmore KE. Effects of Reduced Connexin43 Function on Mandibular Morphology and Osteogenesis in Mutant Mouse Models of Oculodentodigital Dysplasia. Calcif Tissue Int 2020; 107:611-624. [PMID: 32902679 DOI: 10.1007/s00223-020-00753-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 08/29/2020] [Indexed: 10/23/2022]
Abstract
Mutations in the gene encoding the gap-junctional protein connexin43 (Cx43) are the cause of the human disease oculodentodigital dysplasia (ODDD). The mandible is often affected in this disease, with clinical reports describing both mandibular overgrowth and conversely, retrognathia. These seemingly opposing observations underscore our relative lack of understanding of how ODDD affects mandibular morphology. Using two mutant mouse models that mimic the ODDD phenotype (I130T/+ and G60S/+), we sought to uncover how altered Cx43 function may affect mandibular development. Specifically, mandibles of newborn mice were imaged using micro-CT, to enable statistical comparisons of shape. Tissue-level comparisons of key regions of the mandible were conducted using histomorphology, and we quantified the mRNA expression of several cartilage and bone cell differentiation markers. Both G60S/+ and I130T/+ mutant mice had altered mandibular morphology compared to their wildtype counterparts, and the morphological effects were similarly localized for both mutants. Specifically, the biggest phenotypic differences in mutant mice were focused in regions exposed to mechanical forces, such as alveolar bone, muscular attachment sites, and articular surfaces. Histological analyses revealed differences in ossification of the intramembranous bone of the mandibles of both mutant mice compared to their wildtype littermates. However, chondrocyte organization within the secondary cartilages of the mandible was unaffected in the mutant mice. Overall, our results suggest that the morphological differences seen in G60S/+ and I130T/+ mouse mandibles are due to delayed ossification and suggest that mechanical forces may exacerbate the effects of ODDD on the skeleton.
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Affiliation(s)
- Alyssa C Moore
- Department of Anatomy & Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
| | - Jessica Wu
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
| | - Elizabeth Jewlal
- Department of Anatomy & Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
| | - Kevin Barr
- Department of Anatomy & Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
| | - Dale W Laird
- Department of Anatomy & Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
| | - Katherine E Willmore
- Department of Anatomy & Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada.
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27
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Feng S, Bao L, Qiu G, Liao Z, Deng Z, Chen N, Chu Y, Luo Z, Jin Y, Li X, Yang Y, Zhao L. [Observation of dendrite osteocytes of mice at different developmental stages using Ploton silver staining and phalloidin staining]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2020; 40:1656-1661. [PMID: 33243734 DOI: 10.12122/j.issn.1673-4254.2020.11.19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To assess the value of Ploton silver staining and phalloidin-iFlour 488 staining in observation of the morphology of osteocyte dendrites of mice at different developmental stages. METHODS The humerus and femurs were harvested from mice at 0 (P0), 5 (P5), 15 (P15), 21 (P21), 28 (P28), and 35 days (P35) after birth to prepare cryo-sections and paraffin sections. HE staining of P35 mouse femur sections served as a reference for observing osteocytes in the trabecular bone and cortical bone. The humeral sections at different developmental stages were stained with Ploton silver staining to observe the morphology of osteocytes and canaliculi, and the canalicular lengths in the cortical and trabecular bones of the humerus of the mice in each developmental stage were recorded. The cryo-sections of the humerus from P10 and P15 mice were stained with phalloidin iFlour-488 to observe the morphology of osteocytes and measurement of the length of osteocyte dendrites in the cortical bone. RESULTS In the trabecular bone of the humerus of P0-P15 mice, Ploton silver staining only visualized the outline of the osteocytes, and the morphology of the canaliculi was poorly defined. In P21 or older mice, Ploton silver staining revealed the morphology of the trabecular bone osteocytes and the canaliculi, which were neatly arranged and whose lengths increased significantly with age (P21 vs P28, P < 0.05; P21 vs P35, P < 0.05). In the humeral cortical bone of P15 mice, the morphology of the osteocytes and canalicular could be observed with Ploton silver staining, and the length of the regularly arranged canaliculi of the osteocytes increased significantly with age (P15 vs P21, P < 0.005; P15 vs P28, P < 0.0001; P15 vs P35, P < 0.0001). Phalloidin iFlour-488 staining was capable of visualizing the complete morphology of the osteocytes at P10 and P15; the osteocyte dendrites elongated progressively with age (P10 vs P15, P < 0.01) to form connections with the surrounding osteocytes. CONCLUSIONS Mouse osteocyte dendrites elongate progressively and their arrangement gradually becomes regular with age. Ploton silver staining can clearly visualize the morphology of the osteocytes and the canaliculi in adult mice but not in mice in early stages of development. Phalloidin iFlour-488 staining for labeling the cytoskeleton can be applied for mouse osteocytes at all developmental stages and allows morphological observation of mouse osteocytes in early developmental stages.
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Affiliation(s)
- Shuhao Feng
- Department of Joint and Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.,Department of Developmental Biology, Harvard School of Dental Medicine, Harvard University, Boston 02115, USA
| | - Liangxiao Bao
- Department of Joint and Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Gengtao Qiu
- Department of Joint and Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Zheting Liao
- Department of Joint and Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Zhonghao Deng
- Department of Joint and Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Nachun Chen
- Department of Joint and Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Yuhao Chu
- Department of Joint and Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Ziheng Luo
- Department of Joint and Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Yu Jin
- Department of Joint and Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Xiaoyu Li
- Department of Joint and Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Yingzi Yang
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard University, Boston 02115, USA
| | - Liang Zhao
- Department of Joint and Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
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28
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Carina V, Della Bella E, Costa V, Bellavia D, Veronesi F, Cepollaro S, Fini M, Giavaresi G. Bone's Response to Mechanical Loading in Aging and Osteoporosis: Molecular Mechanisms. Calcif Tissue Int 2020; 107:301-318. [PMID: 32710266 DOI: 10.1007/s00223-020-00724-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 07/08/2020] [Indexed: 02/07/2023]
Abstract
Mechanotransduction is pivotal in the maintenance of homeostasis in different tissues and involves multiple cell signaling pathways. In bone, mechanical stimuli regulate the balance between bone formation and resorption; osteocytes play a central role in this regulation. Dysfunctions in mechanotransduction signaling or in osteocytes response lead to an imbalance in bone homeostasis. This alteration is very relevant in some conditions such as osteoporosis and aging. Both are characterized by increased bone weakness due to different causes, for example, the increase of osteocyte apoptosis that cause an alteration of fluid space, or the alteration of molecular pathways. There are intertwined yet very different mechanisms involved among the cell-intrinsic effects of aging on bone, the cell-intrinsic and tissue-level effects of estrogen/androgen withdrawal on bone, and the effects of reduced mechanical loading on bone, which are all involved to some degree in how aged bone fails to respond properly to stress/strain compared to younger bone. This review aims at clarifying how the cellular and molecular pathways regulated and induced in bone by mechanical stimulation are altered with aging and in osteoporosis, to highlight new possible targets for antiresorptive or anabolic bone therapeutic approaches.
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Affiliation(s)
- Valeria Carina
- IRCCS Istituto Ortopedico Rizzoli, SC Scienze e Tecnologie Chirurgiche - SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, Via Di Barbiano, 1/10, 40136, Bologna, Italy.
| | | | - Viviana Costa
- IRCCS Istituto Ortopedico Rizzoli, SC Scienze e Tecnologie Chirurgiche - SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, Via Di Barbiano, 1/10, 40136, Bologna, Italy
| | - Daniele Bellavia
- IRCCS Istituto Ortopedico Rizzoli, SC Scienze e Tecnologie Chirurgiche - SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, Via Di Barbiano, 1/10, 40136, Bologna, Italy
| | - Francesca Veronesi
- IRCCS Istituto Ortopedico Rizzoli, SC Scienze e Tecnologie Chirurgiche - SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, Via Di Barbiano, 1/10, 40136, Bologna, Italy
| | - Simona Cepollaro
- IRCCS Istituto Ortopedico Rizzoli, SC Scienze e Tecnologie Chirurgiche - SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, Via Di Barbiano, 1/10, 40136, Bologna, Italy
| | - Milena Fini
- IRCCS Istituto Ortopedico Rizzoli, SC Scienze e Tecnologie Chirurgiche - SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, Via Di Barbiano, 1/10, 40136, Bologna, Italy
| | - Gianluca Giavaresi
- IRCCS Istituto Ortopedico Rizzoli, SC Scienze e Tecnologie Chirurgiche - SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, Via Di Barbiano, 1/10, 40136, Bologna, Italy
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29
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Shen H, Schwartz AG, Civitelli R, Thomopoulos S. Connexin 43 Is Necessary for Murine Tendon Enthesis Formation and Response to Loading. J Bone Miner Res 2020; 35:1494-1503. [PMID: 32227614 PMCID: PMC7725385 DOI: 10.1002/jbmr.4018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 03/08/2020] [Accepted: 03/21/2020] [Indexed: 12/28/2022]
Abstract
The enthesis is a mineralized fibrocartilage transition that attaches tendon to bone and is vital for musculoskeletal function. Despite recent studies demonstrating the necessity of muscle loading for enthesis formation, the mechanisms that regulate enthesis formation and mechanoresponsiveness remain unclear. Therefore, the current study investigated the role of the gap junction protein connexin 43 in these processes by deleting Gja1 (the Cx43 gene) in the tendon and enthesis. Compared with their wild-type (WT) counterparts, mice lacking Cx43 showed disrupted entheseal cell alignment, reduced mineralized fibrocartilage, and impaired biomechanical properties of the supraspinatus tendon entheses during postnatal development. Cx43-deficient mice also exhibited reduced ability to complete a treadmill running protocol but no apparent deficits in daily activity, metabolic indexes, shoulder muscle size, grip strength, and major trabecular bone properties of the adjacent humeral head. To examine enthesis mechanoresponsiveness, young adult mice were subjected to modest treadmill exercise. Gja1 deficiency in the tendon and enthesis reduced entheseal anabolic responses to treadmill exercise: WT mice had increased expression of Sox9, Ihh, and Gli1 and increased Brdu incorporation, whereas Cx43-deficient mice showed no changes or decreased levels with exercise. Collectively, the results demonstrated an essential role for Cx43 in postnatal tendon enthesis formation, function, and response to loading; results further provided evidence implicating a link between Cx43 function and the hedgehog signaling pathway. © 2020 American Society for Bone and Mineral Research.
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Affiliation(s)
- Hua Shen
- Department of Orthopaedic Surgery, Washington University, St. Louis, MO, USA
| | - Andrea G Schwartz
- Department of Orthopaedic Surgery, Washington University, St. Louis, MO, USA
| | - Roberto Civitelli
- Department of Internal Medicine, Division of Bone and Mineral Disease, Washington University, St. Louis, MO, USA
| | - Stavros Thomopoulos
- Department of Orthopedic Surgery, Columbia University, New York, NY, USA.,Department of Biomedical Engineering, Columbia University, New York, NY, USA
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30
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Qin L, Liu W, Cao H, Xiao G. Molecular mechanosensors in osteocytes. Bone Res 2020; 8:23. [PMID: 32550039 PMCID: PMC7280204 DOI: 10.1038/s41413-020-0099-y] [Citation(s) in RCA: 186] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 04/07/2020] [Accepted: 04/17/2020] [Indexed: 12/11/2022] Open
Abstract
Osteocytes, the most abundant and long-lived cells in bone, are the master regulators of bone remodeling. In addition to their functions in endocrine regulation and calcium and phosphate metabolism, osteocytes are the major responsive cells in force adaptation due to mechanical stimulation. Mechanically induced bone formation and adaptation, disuse-induced bone loss and skeletal fragility are mediated by osteocytes, which sense local mechanical cues and respond to these cues in both direct and indirect ways. The mechanotransduction process in osteocytes is a complex but exquisite regulatory process between cells and their environment, between neighboring cells, and between different functional mechanosensors in individual cells. Over the past two decades, great efforts have focused on finding various mechanosensors in osteocytes that transmit extracellular mechanical signals into osteocytes and regulate responsive gene expression. The osteocyte cytoskeleton, dendritic processes, Integrin-based focal adhesions, connexin-based intercellular junctions, primary cilium, ion channels, and extracellular matrix are the major mechanosensors in osteocytes reported so far with evidence from both in vitro and in vitro studies. This review aims to give a systematic introduction to osteocyte mechanobiology, provide details of osteocyte mechanosensors, and discuss the roles of osteocyte mechanosensitive signaling pathways in the regulation of bone homeostasis.
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Affiliation(s)
- Lei Qin
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
| | - Wen Liu
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
| | - Huiling Cao
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
| | - Guozhi Xiao
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and School of Medicine, Southern University of Science and Technology, Shenzhen, 518055 China
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31
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Morrell AE, Robinson ST, Silva MJ, Guo XE. Mechanosensitive Ca 2+ signaling and coordination is diminished in osteocytes of aged mice during ex vivo tibial loading. Connect Tissue Res 2020; 61:389-398. [PMID: 31931640 PMCID: PMC7785095 DOI: 10.1080/03008207.2020.1712377] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Purpose: The osteocyte is considered the major mechanosensor in bone, capable of detecting forces at a cellular level to coordinate bone formation and resorption. The pathology of age-related bone loss, a hallmark of osteoporosis, is attributed in part to impaired osteocyte mechanosensing. However, real-time evidence of the effect of aging on osteocyte responses to mechanical load is lacking. Intracellular calcium (Ca2+) oscillations have been characterized as an early mechanosensitive response in osteocytes in systems of multiple scales and thus can serve as a real-time measure of osteocyte mechanosensitivity. Our objective was to utilize an ex vivo model to investigate potentially altered mechanosensing in the osteocyte network with aging.Methods: Tibiae were explanted from young-adult (5 mo) and aged (22 mo) female mice and incubated with Fluo-8 AM to visualize osteocyte intracellular Ca2+. Whole tibiae were cyclically loaded while in situ osteocyte Ca2+ dynamics were simultaneously imaged with confocal microscopy. Responsive osteocyte percentage and Ca2+ peak characteristics were quantified, as well as signaling synchrony between paired cells in the field of view.Results: Fewer osteocytes responded to mechanical loading in aged mice compared to young-adult and did so in a delayed manner. Osteocytes from aged mice also lacked the well-correlated relationship between Ca2+ signaling synchrony and cell-cell distance exhibited by young-adult osteocytes.Conclusions: We have demonstrated, for the first time, real-time evidence of the diminished mechanosensing and lack of signaling coordination in aged osteocyte networks in tibial explants, which may contribute to pathology of age-induced bone loss.
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Affiliation(s)
- Andrea E. Morrell
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Samuel T. Robinson
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Matthew J. Silva
- Department of Orthopaedic Surgery, Musculoskeletal Research Center, Washington University, St. Louis, MO, USA,Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
| | - X. Edward Guo
- Department of Biomedical Engineering, Columbia University, New York, NY, USA,Corresponding author: X. Edward Guo, PhD, Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, Mail Code 8904,1210 Amsterdam Avenue, New York, NY 10027, USA.
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32
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Curtis KJ, Oberman AG, Niebur GL. Effects of mechanobiological signaling in bone marrow on skeletal health. Ann N Y Acad Sci 2019; 1460:11-24. [PMID: 31508828 DOI: 10.1111/nyas.14232] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/09/2019] [Accepted: 08/15/2019] [Indexed: 01/27/2023]
Abstract
Bone marrow is a cellular tissue that forms within the pore space and hollow diaphysis of bones. As a tissue, its primary function is to support the hematopoietic progenitor cells that maintain the populations of both erythroid and myeloid lineage cells in the bone marrow, making it an essential element of normal mammalian physiology. However, bone's primary function is load bearing, and deformations induced by external forces are transmitted to the encapsulated marrow. Understanding the effects of these mechanical inputs on marrow function and adaptation requires knowledge of the material behavior of the marrow at multiple scales, the loads that are applied, and the mechanobiology of the cells. This paper reviews the current state of knowledge of each of these factors. Characterization of the marrow mechanical environment and its role in skeletal health and other marrow functions remains incomplete, but research on the topic is increasing, driven by interest in skeletal adaptation and the mechanobiology of cancer metastasis.
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Affiliation(s)
- Kimberly J Curtis
- Tissue Mechanics Laboratory, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, Indiana.,Advanced Diagnostics and Therapeutics Initiative, University of Notre Dame, Notre Dame, Indiana
| | - Alyssa G Oberman
- Tissue Mechanics Laboratory, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, Indiana
| | - Glen L Niebur
- Tissue Mechanics Laboratory, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, Indiana.,Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana.,Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana
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33
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Xie Y, Zhang L, Xiong Q, Gao Y, Ge W, Tang P. Bench-to-bedside strategies for osteoporotic fracture: From osteoimmunology to mechanosensation. Bone Res 2019; 7:25. [PMID: 31646015 PMCID: PMC6804735 DOI: 10.1038/s41413-019-0066-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 06/20/2019] [Accepted: 06/21/2019] [Indexed: 12/16/2022] Open
Abstract
Osteoporosis is characterized by a decrease in bone mass and strength, rendering people prone to osteoporotic fractures caused by low-energy forces. The primary treatment strategy for osteoporotic fractures is surgery; however, the compromised and comminuted bones in osteoporotic fracture sites are not conducive to optimum reduction and rigid fixation. In addition, these patients always exhibit accompanying aging-related disorders, including high inflammatory status, decreased mechanical loading and abnormal skeletal metabolism, which are disadvantages for fracture healing around sites that have undergone orthopedic procedures. Since the incidence of osteoporosis is expected to increase worldwide, orthopedic surgeons should pay more attention to comprehensive strategies for improving the poor prognosis of osteoporotic fractures. Herein, we highlight the molecular basis of osteoimmunology and bone mechanosensation in different healing phases of elderly osteoporotic fractures, guiding perioperative management to alleviate the unfavorable effects of insufficient mechanical loading, high inflammatory levels and pathogen infection. The well-informed pharmacologic and surgical intervention, including treatment with anti-inflammatory drugs and sufficient application of antibiotics, as well as bench-to-bedside strategies for bone augmentation and hardware selection, should be made according to a comprehensive understanding of bone biomechanical properties in addition to the remodeling status of osteoporotic bones, which is necessary for creating proper biological and mechanical environments for bone union and remodeling. Multidisciplinary collaboration will facilitate the improvement of overall osteoporotic care and reduction of secondary fracture incidence.
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Affiliation(s)
- Yong Xie
- Department of Orthopedics, Chinese PLA General Hospital, Beijing, China
| | - Licheng Zhang
- Department of Orthopedics, Chinese PLA General Hospital, Beijing, China
| | - Qi Xiong
- Department of Oncology, Chinese PLA General Hospital, Beijing, China
| | - Yanpan Gao
- State Key Laboratory of Medical Molecular Biology and Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China
| | - Wei Ge
- State Key Laboratory of Medical Molecular Biology and Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China
| | - Peifu Tang
- Department of Orthopedics, Chinese PLA General Hospital, Beijing, China
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Transforming growth factor-β1 up-regulates connexin43 expression in osteocytes via canonical Smad-dependent signaling pathway. Biosci Rep 2018; 38:BSR20181678. [PMID: 30482881 PMCID: PMC6294634 DOI: 10.1042/bsr20181678] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/20/2018] [Accepted: 11/23/2018] [Indexed: 02/05/2023] Open
Abstract
Connexin 43 (Cx43)-mediated gap junctional intercellular communication (GJIC) has been shown to be important in regulating multiple functions of bone cells. Transforming growth factor-β1 (TGF-β1) exhibited controversial effects on the expression of Cx43 in different cell types. To date, the effect of TGF-β1 on the Cx43 expression of osteocytes is still unknown. In the present study, we detected the expression of TGF-β1 in osteocytes and bone tissue, and then used recombinant mouse TGF-β1 to elucidate its effect on gap junctions (GJs) of osteocytes. Our data indicated that TGF-β1 up-regulated both mRNA and protein expression of Cx43 in osteocytes. Together with down-regulation of Cx43 expression after being treated with TGF-β type I receptor inhibitor Repsox, we deduced that TGF-β1 can positively regulate Cx43 expression in osteocytes. Thus we next focussed on the downstream signals of TGF-β and found that TGF-β1-mediated smads, Smad3 and Smad4, to translocate into nucleus. These translocated signal proteins bind to the promoter of Gja1 which was responsible for the changed expression of Cx43. The present study provides evidence that TGF-β1 can enhance GJIC between osteocytes through up-regulating Cx43 expression and the underlying mechanism involved in the activation of Smad-dependent pathway.
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Hinton PV, Rackard SM, Kennedy OD. In Vivo Osteocyte Mechanotransduction: Recent Developments and Future Directions. Curr Osteoporos Rep 2018; 16:746-753. [PMID: 30406580 DOI: 10.1007/s11914-018-0485-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
PURPOSE OF REVIEW Mechanical loading is an essential stimulus for skeletal tissues. Osteocytes are primarily responsible for sensing mechanical stimuli in bone and for orchestrating subsequent responses. This is critical for maintaining homeostasis, and responding to injury/disease. The osteocyte mechanotransduction pathway, and the downstream effects it mediates, is highly complex. In vivo models have proved invaluable in understanding this process. This review summarizes the commonly used models, as well as more recently developed ones, and describes how they are used to address emerging questions in the field. RECENT FINDINGS Minimally invasive animal models can be used to determine mechanisms of osteocyte mechanotransduction, at the cell and molecular level, while simultaneously reducing potentially confounding responses such as inflammation/wound-healing. The details of osteocyte mechanotransduction in bone are gradually becoming clearer. In vivo model systems are a key tool in pursing this question. Advances in this field are explored and discussed in this review.
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Affiliation(s)
- Paige V Hinton
- Department of Anatomy & Tissue Engineering Research Group, Royal College of Surgeons in Ireland, 123 St Stephens Green, Dublin 2, Ireland
| | - Susan M Rackard
- School of Veterinary Medicine, Veterinary Science Centre, University College Dublin, Dublin 4, Ireland
| | - Oran D Kennedy
- Department of Anatomy & Tissue Engineering Research Group, Royal College of Surgeons in Ireland, 123 St Stephens Green, Dublin 2, Ireland.
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Gago-Fuentes R, Bechberger JF, Varela-Eirin M, Varela-Vazquez A, Acea B, Fonseca E, Naus CC, Mayan MD. The C-terminal domain of connexin43 modulates cartilage structure via chondrocyte phenotypic changes. Oncotarget 2018; 7:73055-73067. [PMID: 27682878 PMCID: PMC5341963 DOI: 10.18632/oncotarget.12197] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 09/16/2016] [Indexed: 12/13/2022] Open
Abstract
Chondrocytes in cartilage and bone cells population express connexin43 (Cx43) and gap junction intercellular communication (GJIC) is essential to synchronize cells for coordinated electrical, mechanical, metabolic and chemical communication in both tissues. Reduced Cx43 connectivity decreases chondrocyte differentiation and defective Cx43 causes skeletal defects. The carboxy terminal domain (CTD) of Cx43 is located in the cytoplasmic side and is key for protein functions. Here we demonstrated that chondrocytes from the CTD-deficient mice, K258stop/Cx43KO and K258stop/K258stop, have reduced GJIC, increased rates of proliferation and reduced expression of collagen type II and proteoglycans. We observed that CTD-truncated mice were significantly smaller in size. Together these results demonstrated that the deletion of the CTD negatively impacts cartilage structure and normal chondrocyte phenotype. These findings suggest that the proteolytic cleavage of the CTD under pathological conditions, such as under the activation of metalloproteinases during tissue injury or inflammation, may account for the deleterious effects of Cx43 in cartilage and bone disorders such as osteoarthritis.
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Affiliation(s)
- Raquel Gago-Fuentes
- CellCOM-SB Research Group, Instituto de Investigación Biomédica de A Coruña (INIBIC), CH-Universitario A Coruña (XXIAC), University of A Coruña, Servizo Galego de Saúde (SERGAS), Xubias de Arriba, 84 15006 A Coruña, Spain
| | - John F Bechberger
- Department of Cellular and Physiological Sciences, The Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z3
| | - Marta Varela-Eirin
- CellCOM-SB Research Group, Instituto de Investigación Biomédica de A Coruña (INIBIC), CH-Universitario A Coruña (XXIAC), University of A Coruña, Servizo Galego de Saúde (SERGAS), Xubias de Arriba, 84 15006 A Coruña, Spain
| | - Adrian Varela-Vazquez
- CellCOM-SB Research Group, Instituto de Investigación Biomédica de A Coruña (INIBIC), CH-Universitario A Coruña (XXIAC), University of A Coruña, Servizo Galego de Saúde (SERGAS), Xubias de Arriba, 84 15006 A Coruña, Spain
| | - Benigno Acea
- CellCOM-SB Research Group, Instituto de Investigación Biomédica de A Coruña (INIBIC), CH-Universitario A Coruña (XXIAC), University of A Coruña, Servizo Galego de Saúde (SERGAS), Xubias de Arriba, 84 15006 A Coruña, Spain
| | - Eduardo Fonseca
- CellCOM-SB Research Group, Instituto de Investigación Biomédica de A Coruña (INIBIC), CH-Universitario A Coruña (XXIAC), University of A Coruña, Servizo Galego de Saúde (SERGAS), Xubias de Arriba, 84 15006 A Coruña, Spain
| | - Christian C Naus
- Department of Cellular and Physiological Sciences, The Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z3
| | - Maria D Mayan
- CellCOM-SB Research Group, Instituto de Investigación Biomédica de A Coruña (INIBIC), CH-Universitario A Coruña (XXIAC), University of A Coruña, Servizo Galego de Saúde (SERGAS), Xubias de Arriba, 84 15006 A Coruña, Spain
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Role of Cx43-Mediated NFкB Signaling Pathway in Ossification of Posterior Longitudinal Ligament: An In Vivo and In Vitro Study. Spine (Phila Pa 1976) 2017; 42:E1334-E1341. [PMID: 28338575 DOI: 10.1097/brs.0000000000002165] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN In vivo and in vitro experiments. OBJECTIVE To illustrate the further molecular mechanism of Cx43-mediated osteoblastic differentiation of ligament cells. SUMMARY OF BACKGROUND DATA Ossification of the posterior longitudinal ligament (OPLL) is one of the main causes of myelopathy in Asians, but its etiology has not been clarified. We have previously found the mechanical stress can upregulate Cx43 expression in ligament cells, which transduces mechanical signal to promote osteoblastic differentiation. METHODS The posterior longitudinal ligaments were collected intraoperatively. Ligament fibroblasts were isolated and cultured, and an in vitro mechanical loading model was established. In vivo and in vitro expression levels of Cx43 protein were compared between OPLL and non-OPLL patients. The activation of nuclear factor (NF)-κB (p65) signal and related inflammatory responses were detected in ligament cells under mechanical loading. The mechanical stress-induced inflammatory response and osteoblastic differentiation of OPLL cells were investigated after the treatment with Cx43 siRNA or NFкB (p65) inhibitor. RESULTS We first confirmed higher Cx43 levels in both in vivo ligament tissue from OPLL patients and in vitro cultured OPLL cells. We also found NFκB (p65) signal and related inflammatory response were activated by mechanical stimulation. The activation of NFκB (p65) signal was dependent upon Cx43, as its knockdown reduced signal. Moreover, treatment with Cx43 siRNA or NFкB (p65) inhibitor significantly decreased the mechanical-induced inflammation response, but partly attenuated mechanical-stimulated osteoblastic differentiation of OPLL cells. CONCLUSION Cx43-mediated NFкB (p65) signal played an important role in mechanical stress-induced OPLL by transduction of mechanical signal, while giving rise to the activation of inflammatory response in ligament fibroblastsLevel of Evidence: N/A.
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Mercatali L, La Manna F, Miserocchi G, Liverani C, De Vita A, Spadazzi C, Bongiovanni A, Recine F, Amadori D, Ghetti M, Ibrahim T. Tumor-Stroma Crosstalk in Bone Tissue: The Osteoclastogenic Potential of a Breast Cancer Cell Line in a Co-Culture System and the Role of EGFR Inhibition. Int J Mol Sci 2017; 18:ijms18081655. [PMID: 28758931 PMCID: PMC5578045 DOI: 10.3390/ijms18081655] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 07/21/2017] [Accepted: 07/25/2017] [Indexed: 12/21/2022] Open
Abstract
Although bone metastases represent a major challenge in the natural history of breast cancer (BC), the complex interactions involved have hindered the development of robust in vitro models. The aim of this work is the development of a preclinical model of cancer and bone stromal cells to mimic the bone microenvironment. We studied the effects on osteoclastogenesis of BC cells and Mesenchymal stem cells (MSC) cultured alone or in combination. We also analyzed: (a) whether the blockade of the Epithelial Growth Factor Receptor (EGFR) pathway modified their influence on monocytes towards differentiation, and (b) the efficacy of bone-targeted therapy on osteoclasts. We evaluated the osteoclastogenesis modulation of human peripheral blood monocytes (PBMC) indirectly induced by the conditioned medium (CM) of the human BC cell line SCP2, cultured singly or with MSC. Osteoclastogenesis was evaluated by TRAP analysis. The effect of the EGFR blockade was assessed by treating the cells with gefitinib, and analyzed with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Western Blot (WB). We observed that SCP2 co-cultured with MSC increased the differentiation of PBMC. This effect was underpinned upon pre-treatment of the co-culture with gefitinib. Co-culture of SCP2 with MSC increased the expression of both the bone-related marker Receptor Activator of Nuclear Factor κB (RANK) and EGFR in BC cells. These upregulations were not affected by the EGFR blockade. The effects of the CM obtained by the cells treated with gefitinib in combination with the treatment of the preosteoclasts with the bone-targeted agents and everolimus enhanced the inhibition of the osteoclastogenesis. Finally, we developed a fully human co-culture system of BC cells and bone progenitor cells. We observed that the interaction of MSC with cancer cells induced in the latter molecular changes and a higher power of inducing osteoclastogenesis. We found that blocking EGFR signaling could be an efficacious strategy for breaking the interactions between cancer and bone cells in order to inhibit bone metastasis.
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Affiliation(s)
- Laura Mercatali
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy.
| | - Federico La Manna
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy.
| | - Giacomo Miserocchi
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy.
| | - Chiara Liverani
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy.
| | - Alessandro De Vita
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy.
| | - Chiara Spadazzi
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy.
| | - Alberto Bongiovanni
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy.
| | - Federica Recine
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy.
| | - Dino Amadori
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy.
| | - Martina Ghetti
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy.
- Biomedical and Neuromotor Sciences Department, University of Bologna, 40123 Bologna, Italy.
| | - Toni Ibrahim
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy.
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Abstract
The primary cilium is a mechanosensor in a variety of mammalian cell types, initiating and directing intracellular signalling cascades in response to external stimuli. When primary cilia formation is disrupted, cells have diminished mechanosensitivity and an abrogated response to mechanical stimulation. Due to this important role, we hypothesised that increasing primary cilia length would enhance the downstream response and therefore, mechanosensitivity. To test this hypothesis, we increased osteocyte primary cilia length with fenoldopam and lithium and found that cells with longer primary cilia were more mechanosensitive. Furthermore, fenoldopam treatment potentiated adenylyl cyclase activity and was able to recover primary cilia form and sensitivity in cells with impaired cilia. This work demonstrates that modulating the structure of the primary cilium directly impacts cellular mechanosensitivity. Our results implicate cilium length as a potential therapeutic target for combating numerous conditions characterised by impaired cilia function.
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Abstract
Osteocytes are differentiated osteoblasts that become surrounded by matrix during the process of bone formation. Acquisition of the osteocyte phenotype is achieved by profound changes in gene expression that facilitate adaptation to the changing cellular environment and constitute the molecular signature of osteocytes. During osteocytogenesis, the expression of genes that are characteristic of the osteoblast are altered and the expression of genes and/or proteins that impart dendritic cellular morphology, regulate matrix mineralization and control the function of cells at the bone surface are ordely modulated. The discovery of mutations in human osteocytic genes has contributed, in a large part, to our understanding of the role of osteocytes in bone homeostasis. Osteocytes are targets of the mechanical force imposed on the skeleton and have a critical role in integrating mechanosensory pathways with the action of hormones, which thereby leads to the orchestrated response of bone to environmental cues. Current, therapeutic approaches harness this accumulating knowledge by targeting osteocytic signalling pathways and messengers to improve skeletal health.
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Affiliation(s)
- Lilian I. Plotkin
- Department of Anatomy and Cell Biology, Indiana University School of Medicine
- Roudebush Veterans Administration Medical Center, Indianapolis, IN
| | - Teresita Bellido
- Department of Anatomy and Cell Biology, Indiana University School of Medicine
- Department of Medicine, Division of Endocrinology, Indiana University School of Medicine
- Roudebush Veterans Administration Medical Center, Indianapolis, IN
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Prideaux M, Findlay DM, Atkins GJ. Osteocytes: The master cells in bone remodelling. Curr Opin Pharmacol 2016; 28:24-30. [DOI: 10.1016/j.coph.2016.02.003] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 01/14/2016] [Accepted: 02/09/2016] [Indexed: 10/22/2022]
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Li H, Cui Y, Luan J, Zhang X, Li C, Zhou X, Shi L, Wang H, Han J. PRELP (proline/arginine-rich end leucine-rich repeat protein) promotes osteoblastic differentiation of preosteoblastic MC3T3-E1 cells by regulating the β-catenin pathway. Biochem Biophys Res Commun 2016; 470:558-562. [DOI: 10.1016/j.bbrc.2016.01.106] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 01/17/2016] [Indexed: 10/22/2022]
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Inada M, Takita M, Yokoyama S, Watanabe K, Tominari T, Matsumoto C, Hirata M, Maru Y, Maruyama T, Sugimoto Y, Narumiya S, Uematsu S, Akira S, Murphy G, Nagase H, Miyaura C. Direct Melanoma Cell Contact Induces Stromal Cell Autocrine Prostaglandin E2-EP4 Receptor Signaling That Drives Tumor Growth, Angiogenesis, and Metastasis. J Biol Chem 2015; 290:29781-93. [PMID: 26475855 DOI: 10.1074/jbc.m115.669481] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Indexed: 01/11/2023] Open
Abstract
The stromal cells associated with tumors such as melanoma are significant determinants of tumor growth and metastasis. Using membrane-bound prostaglandin E synthase 1 (mPges1(-/-)) mice, we show that prostaglandin E2 (PGE2) production by host tissues is critical for B16 melanoma growth, angiogenesis, and metastasis to both bone and soft tissues. Concomitant studies in vitro showed that PGE2 production by fibroblasts is regulated by direct interaction with B16 cells. Autocrine activity of PGE2 further regulates the production of angiogenic factors by fibroblasts, which are key to the vascularization of both primary and metastatic tumor growth. Similarly, cell-cell interactions between B16 cells and host osteoblasts modulate mPGES-1 activity and PGE2 production by the osteoblasts. PGE2, in turn, acts to stimulate receptor activator of NF-κB ligand expression, leading to osteoclast differentiation and bone erosion. Using eicosanoid receptor antagonists, we show that PGE2 acts on osteoblasts and fibroblasts in the tumor microenvironment through the EP4 receptor. Metastatic tumor growth and vascularization in soft tissues was abrogated by an EP4 receptor antagonist. EP4-null Ptger4(-/-) mice do not support B16 melanoma growth. In vitro, an EP4 receptor antagonist modulated PGE2 effects on fibroblast production of angiogenic factors. Our data show that B16 melanoma cells directly influence host stromal cells to generate PGE2 signals governing neoangiogenesis and metastatic growth in bone via osteoclast erosive activity as well as angiogenesis in soft tissue tumors.
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Affiliation(s)
- Masaki Inada
- From the Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan, the Global Innovation Research Organization, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan
| | - Morichika Takita
- From the Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan, the Department of Pharmacology, Tokyo Women's Medical University, Tokyo 162-8666, Japan
| | - Satoshi Yokoyama
- From the Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan
| | - Kenta Watanabe
- From the Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan
| | - Tsukasa Tominari
- From the Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan, the Global Innovation Research Organization, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan
| | - Chiho Matsumoto
- From the Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan
| | - Michiko Hirata
- From the Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan
| | - Yoshiro Maru
- the Department of Pharmacology, Tokyo Women's Medical University, Tokyo 162-8666, Japan
| | - Takayuki Maruyama
- the Minase Research Institutes, Ono Pharmaceutical Co. Ltd, Osaka 618-8585, Japan
| | - Yukihiko Sugimoto
- the Department of Pharmaceutical Biochemistry, Graduate School of Pharmaceutical Science, Kumamoto University, Kumamoto 862-0973, Japan
| | - Shuh Narumiya
- the Department of Pharmacology, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Satoshi Uematsu
- the Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan, the Department of Mucosal Immunology, School of Medicine, Chiba University, Chiba 260-8670, Japan, the Division of Innate Immune, Regulation, International Research, and Development, Center for Mucosal Vaccines, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Shizuo Akira
- the Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Gillian Murphy
- the Global Innovation Research Organization, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan, the Department of Oncology, University of Cambridge, Cancer Research UK, Cambridge Institute, Li Ka Shing Centre, Cambridge CB2 0RE, United Kingdom, and
| | - Hideaki Nagase
- the Global Innovation Research Organization, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan, the Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Oxford OX3 7FY, United Kingdom
| | - Chisato Miyaura
- From the Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan, the Global Innovation Research Organization, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan,
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Connexin 43 promotes ossification of the posterior longitudinal ligament through activation of the ERK1/2 and p38 MAPK pathways. Cell Tissue Res 2015; 363:765-73. [DOI: 10.1007/s00441-015-2277-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 08/06/2015] [Indexed: 11/25/2022]
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45
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Plotkin LI, Stains JP. Connexins and pannexins in the skeleton: gap junctions, hemichannels and more. Cell Mol Life Sci 2015; 72:2853-67. [PMID: 26091748 PMCID: PMC4503509 DOI: 10.1007/s00018-015-1963-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Accepted: 06/11/2015] [Indexed: 10/23/2022]
Abstract
Regulation of bone homeostasis depends on the concerted actions of bone-forming osteoblasts and bone-resorbing osteoclasts, controlled by osteocytes, cells derived from osteoblasts surrounded by bone matrix. The control of differentiation, viability and function of bone cells relies on the presence of connexins. Connexin43 regulates the expression of genes required for osteoblast and osteoclast differentiation directly or by changing the levels of osteocytic genes, and connexin45 may oppose connexin43 actions in osteoblastic cells. Connexin37 is required for osteoclast differentiation and its deletion results in increased bone mass. Less is known on the role of connexins in cartilage, ligaments and tendons. Connexin43, connexin45, connexin32, connexin46 and connexin29 are expressed in chondrocytes, while connexin43 and connexin32 are expressed in ligaments and tendons. Similarly, although the expression of pannexin1, pannexin2 and pannexin3 has been demonstrated in bone and cartilage cells, their function in these tissues is not fully understood.
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Affiliation(s)
- Lilian I Plotkin
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Dr., MS 5035, Indianapolis, IN, 46202, USA,
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