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Shi V, Morgan EF. Estrogen and estrogen receptors mediate the mechanobiology of bone disease and repair. Bone 2024; 188:117220. [PMID: 39106937 PMCID: PMC11392539 DOI: 10.1016/j.bone.2024.117220] [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: 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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Ismail OM, El-Omar OM, Said UN. Exploring the Role of Urocortin in Osteoporosis. Cureus 2023; 15:e38978. [PMID: 37313093 PMCID: PMC10259878 DOI: 10.7759/cureus.38978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2023] [Indexed: 06/15/2023] Open
Abstract
Osteoporosis is a debilitating disease that affects over 200 million people worldwide. Overactive osteoclast activity leads to micro-architectural defects and low bone mass. This culminates in fragility fractures, such as femoral neck fractures. Treatments currently available either are not completely effective or have considerable side effects; thus, there is a need for more effective treatments. The urocortin (Ucn) family, composed of urocortin 1 (Ucn1), urocortin 2 (Ucn2), urocortin 3 (Ucn3), corticotropin-releasing factor (CRF) and corticotropin-releasing factor-binding protein (CRF-BP), exerts a wide range of effects throughout the body. Ucn1 has been shown to inhibit murine osteoclast activity. This review article will aim to bridge the gap between existing knowledge of Ucn and whether it can affect human osteoclasts.
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Affiliation(s)
- Omar M Ismail
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, GBR
| | - Omar M El-Omar
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, GBR
| | - Umar N Said
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, GBR
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3
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Hao D, Liu R, Fernandez TG, Pivetti C, Jackson JE, Kulubya ES, Jiang HJ, Ju HY, Liu WL, Panitch A, Lam KS, Leach JK, Farmer DL, Wang A. A bioactive material with dual integrin-targeting ligands regulates specific endogenous cell adhesion and promotes vascularized bone regeneration in adult and fetal bone defects. Bioact Mater 2023; 20:179-193. [PMID: 35663336 PMCID: PMC9160290 DOI: 10.1016/j.bioactmat.2022.05.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 05/19/2022] [Accepted: 05/19/2022] [Indexed: 12/18/2022] Open
Abstract
Significant progress has been made in designing bone materials capable of directing endogenous cells to promote vascularized bone regeneration. However, current strategies lack regulation of the specific endogenous cell populations for vascularized bone regeneration, thus leading to adverse tissue formation and decreased regenerative efficiency. Here, we engineered a biomaterial to regulate endogenous cell adhesion and promote vascularized bone regeneration. The biomaterial works by presenting two synthetic ligands, LLP2A and LXW7, explicitly targeting integrins α4β1 and αvβ3, respectively, expressed on the surfaces of the cells related to bone formation and vascularization, such as mesenchymal stem cells (MSCs), osteoblasts, endothelial progenitor cells (EPCs), and endothelial cells (ECs). In vitro, the LLP2A/LXW7 modified biomaterial improved the adhesion of MSCs, osteoblasts, EPCs, and ECs via integrin α4β1 and αvβ3, respectively. In an adult rat calvarial bone defect model, the LLP2A/LXW7 modified biomaterial enhanced bone formation and vascularization by synergistically regulating endogenous cells with osteogenic and angiogenic potentials, such as DLX5+ cells, osteocalcin+ cells, CD34+/CD45- cells and CD31+ cells. In a fetal sheep spinal bone defect model, the LLP2A/LXW7 modified biomaterial augmented bone formation and vascularization without any adverse effects. This innovative biomaterial offers an off-the-shelf, easy-to-use, and biologically safe product suitable for vascularized bone regeneration in both fetal and adult disease environments. Two integrin-binding ligands for constructing vascularized bone biomaterial. Extracellular matrix (ECM)-mimicking collagen-based biomaterial with specific integrin binding sites for cell adhesion. Biomaterial regulates adhesion of endogenous stem cells with osteogenic and angiogenic potentials. Biomaterial promotes vascularized bone formation in adult and fetal bone defects without safety issues. An easy-to-make and off-the-shelf biomaterial for treatment of clinical bone diseases.
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Affiliation(s)
- Dake Hao
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA, 95817, United States
| | - Ruiwu Liu
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
| | - Tomas Gonzalez Fernandez
- Department of Biomedical Engineering, University of California Davis, Davis, CA, 95616, United States
| | - Christopher Pivetti
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA, 95817, United States
| | - Jordan Elizabeth Jackson
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
| | - Edwin Samuel Kulubya
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
| | - Hong-Jiang Jiang
- Wendeng Orthopaedic Hospital, No. 1 Fengshan Road, Wendeng, 264400, Shandong, China
| | - Hai-Yang Ju
- Wendeng Orthopaedic Hospital, No. 1 Fengshan Road, Wendeng, 264400, Shandong, China
| | - Wen-Liang Liu
- Wendeng Orthopaedic Hospital, No. 1 Fengshan Road, Wendeng, 264400, Shandong, China
| | - Alyssa Panitch
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
- Department of Biomedical Engineering, University of California Davis, Davis, CA, 95616, United States
| | - Kit S. Lam
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
| | - J. Kent Leach
- Department of Orthopaedic Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
| | - Diana L. Farmer
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA, 95817, United States
| | - Aijun Wang
- Department of Surgery, School of Medicine, University of California Davis, Sacramento, CA, 95817, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA, 95817, United States
- Department of Biomedical Engineering, University of California Davis, Davis, CA, 95616, United States
- Corresponding author. Center for Surgical Bioengineering, Department of Surgery, School of Medicine, University of California, Davis, 4625 2nd Ave., Research II, Suite 3005, Sacramento, CA, 95817, USA.
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4
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Calejo I, Reis RL, Domingues RMA, Gomes ME. Texturing Hierarchical Tissues by Gradient Assembling of Microengineered Platelet-Lysates Activated Fibers. Adv Healthc Mater 2022; 11:e2102076. [PMID: 34927396 DOI: 10.1002/adhm.202102076] [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: 09/28/2021] [Revised: 11/14/2021] [Indexed: 11/07/2022]
Abstract
The heterogeneity of hierarchical tissues requires designing multipart engineered constructs as suitable tissue replacements. Herein, the incorporation of platelet lysate (PL) within an electrospun fiber core is proposed aiming for the fabrication of functionally graded 3D scaffolds for heterotypic tissues regeneration, such as tendon-to-bone interfaces. First, anisotropic yarns (A-Yarns) and isotropic threads with nanohydroxyapatite (I-Threads/PL@nHAp) are fabricated to recreate the tendon- and bone-microstructures and both incorporated with PL using emulsion electrospinning for a sustained and local delivery of growth factors, cytokines, and chemokines. Biological performance using human adipose-derived stem cells demonstrates that A-Yarns/PL induce a higher expression of scleraxis, a tenogenic-marker, while in I-Threads/PL@nHAp, higher alkaline phosphatase activity and matrix mineralization suggest an osteogenic commitment without the need for biochemical supplementation compared to controls. As a proof-of-concept, functional 3D gradient scaffolds are fabricated using a weaving technique, resulting in 3D textured hierarchical constructs with gradients in composition and topography. Additionally, the precise delivery of bioactive cues together with in situ biophysical features guide the commitment into a phenotypic gradient exhibiting chondrogenic and osteochondrogenic profiles in the interface of scaffolds. Overall, a promising patch solution for the regeneration of tendon-to-bone tissue interface through the fabrication of PL-functional 3D gradient constructs is demonstrated.
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Affiliation(s)
- Isabel Calejo
- 3B's Research Group i3Bs – Research Institute on Biomaterials, Biodegradables and Biomimetics University of Minho Barco Guimarães 4805‐017 Portugal
| | - Rui L. Reis
- 3B's Research Group i3Bs – Research Institute on Biomaterials, Biodegradables and Biomimetics University of Minho Barco Guimarães 4805‐017 Portugal
| | - Rui M. A. Domingues
- 3B's Research Group i3Bs – Research Institute on Biomaterials, Biodegradables and Biomimetics University of Minho Barco Guimarães 4805‐017 Portugal
| | - Manuela E. Gomes
- 3B's Research Group i3Bs – Research Institute on Biomaterials, Biodegradables and Biomimetics University of Minho Barco Guimarães 4805‐017 Portugal
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5
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Cerqueni G, Scalzone A, Licini C, Gentile P, Mattioli-Belmonte M. Insights into oxidative stress in bone tissue and novel challenges for biomaterials. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2021; 130:112433. [PMID: 34702518 DOI: 10.1016/j.msec.2021.112433] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/08/2021] [Accepted: 09/11/2021] [Indexed: 12/28/2022]
Abstract
The presence of Reactive Oxygen Species (ROS) in bone can influence resident cells behaviour as well as the extra-cellular matrix composition and the tissue architecture. Aging, in addition to excessive overloads, unbalanced diet, smoking, predisposing genetic factors, lead to an increase of ROS and, if it is accompanied with an inappropriate production of scavengers, promotes the generation of oxidative stress that encourages bone catabolism. Furthermore, bone injuries can be triggered by numerous events such as road and sports accidents or tumour resection. Although bone tissue possesses a well-known repair and regeneration capacity, these mechanisms are inefficient in repairing large size defects and bone grafts are often necessary. ROS play a fundamental role in response after the implant introduction and can influence its success. This review provides insights on the mechanisms of oxidative stress generated by an implant in vivo and suitable ways for its modulation. The local delivery of active molecules, such as polyphenols, enhanced bone biomaterial integration evidencing that the management of the oxidative stress is a target for the effectiveness of an implant. Polyphenols have been widely used in medicine for cardiovascular, neurodegenerative, bone disorders and cancer, thanks to their antioxidant and anti-inflammatory properties. In addition, the perspective of new smart biomaterials and molecular medicine for the oxidative stress modulation in a programmable way, by the use of ROS responsive materials or by the targeting of selective molecular pathways involved in ROS generation, will be analysed and discussed critically.
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Affiliation(s)
- Giorgia Cerqueni
- Department of Clinical and Molecular Sciences (DISCLIMO), Università Politecnica delle Marche, Via Tronto 10/a, Ancona 60126, Italy
| | - Annachiara Scalzone
- School of Engineering, Newcastle University, Stephenson Building, Claremont Road, Newcastle upon Tyne NE1 7RU, UK
| | - Caterina Licini
- Department of Clinical and Molecular Sciences (DISCLIMO), Università Politecnica delle Marche, Via Tronto 10/a, Ancona 60126, Italy; Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 204, 10129 Torino, Italy
| | - Piergiorgio Gentile
- School of Engineering, Newcastle University, Stephenson Building, Claremont Road, Newcastle upon Tyne NE1 7RU, UK
| | - Monica Mattioli-Belmonte
- Department of Clinical and Molecular Sciences (DISCLIMO), Università Politecnica delle Marche, Via Tronto 10/a, Ancona 60126, Italy.
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6
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Kim J, Kigami H, Adachi T. Comparative gene expression analysis for pre-osteoblast MC3T3-E1 cells under non-adhesive culture toward osteocyte differentiation. J Biosci Bioeng 2021; 132:651-656. [PMID: 34556421 DOI: 10.1016/j.jbiosc.2021.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/02/2021] [Accepted: 09/02/2021] [Indexed: 12/26/2022]
Abstract
Osteocytes play an important role to modulate the bone remodeling and are also known as terminally differentiated cells originated from the osteoblast precursor cells, but its differentiation mechanism remains unclear. Since an efficient in vitro method to evoke the osteocyte differentiation from the osteoblast precursor cells has not been established, we conducted the comparative gene expression analysis for mouse pre-osteoblast MC3T3-E1 cells in order to elucidate the key factors to induce the osteocyte differentiation from the pre-osteoblast cells. In this study, we prepared four different culture environments by modulating their cell-substrate interaction and cell-cell interaction; (i) low and (ii) high cell density on the adhesive culture models, and (iii) low and (iv) high cell density on the non-adhesive floating culture models. By comparing these conditions in terms of cell-substrate and cell-cell interaction, we showed that the elimination of cell-substrate interaction under non-adhesive floating culture greatly up-regulated the gene expression of osteocyte markers in the pre-osteoblast cells. Moreover, the presence of moderate cell-cell interaction in the non-adhesive spheroid culture further enhanced the up-regulation of osteocyte markers for the pre-osteoblast cells. The results altogether suggest the most appropriate culture environment to induce the in vitro osteocyte differentiation of pre-osteoblast cells.
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Affiliation(s)
- Jeonghyun Kim
- Department of Mechanical Systems Engineering, Nagoya University, Nagoya 464-8603, Japan.
| | - Hiroyuki Kigami
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Kyoto 606-8507, Japan
| | - Taiji Adachi
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Kyoto 606-8507, Japan; Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
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7
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Wakamatsu T, Iwasaki Y, Yamamoto S, Matsuo K, Goto S, Narita I, Kazama JJ, Tanaka K, Ito A, Ozasa R, Nakano T, Miyakoshi C, Onishi Y, Fukuma S, Fukuhara S, Yamato H, Fukagawa M, Akizawa T. Type I Angiotensin II Receptor Blockade Reduces Uremia-Induced Deterioration of Bone Material Properties. J Bone Miner Res 2021; 36:67-79. [PMID: 32786093 PMCID: PMC9328427 DOI: 10.1002/jbmr.4159] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 07/15/2020] [Accepted: 07/27/2020] [Indexed: 12/19/2022]
Abstract
Chronic kidney disease (CKD) is associated with a high incidence of fractures. However, the pathophysiology of this disease is not fully understood, and limited therapeutic interventions are available. This study aimed to determine the impact of type 1 angiotensin II receptor blockade (AT-1RB) on preventing CKD-related fragility fractures and elucidate its pharmacological mechanisms. AT-1RB use was associated with a lower risk of hospitalization due to fractures in 3276 patients undergoing maintenance hemodialysis. In nephrectomized rats, administration of olmesartan suppressed osteocyte apoptosis, skeletal pentosidine accumulation, and apatite disorientation, and partially inhibited the progression of the bone elastic mechanical properties, while the bone mass was unchanged. Olmesartan suppressed angiotensin II-dependent oxidation stress and apoptosis in primary cultured osteocytes in vitro. In conclusion, angiotensin II-dependent intraskeletal oxidation stress deteriorated the bone elastic mechanical properties by promoting osteocyte apoptosis and pentosidine accumulation. Thus, AT-1RB contributes to the underlying pathogenesis of abnormal bone quality in the setting of CKD, possibly by oxidative stress. © 2020 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Takuya Wakamatsu
- Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yoshiko Iwasaki
- Department of Health Sciences, Oita University of Nursing and Health Sciences, Oita, Japan
| | - Suguru Yamamoto
- Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Koji Matsuo
- Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Shin Goto
- Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Ichiei Narita
- Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Junichiro J Kazama
- Department of Nephrology and Hypertension, Fukushima Medical University, Fukushima, Japan
| | - Kennichi Tanaka
- Department of Nephrology and Hypertension, Fukushima Medical University, Fukushima, Japan
| | - Akemi Ito
- Ito Bone Histomorphometry Institute, Niigata, Japan
| | - Ryosuke Ozasa
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Suita, Japan
| | - Takayoshi Nakano
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Suita, Japan
| | - Chisato Miyakoshi
- Department of Healthcare Epidemiology, School of Public Health in the Graduate School of Medicine, Kyoto University, Kyoto, Japan.,Department of Pediatrics, Kobe City Medical Center General Hospital, Kobe, Japan.,Institute for Health Outcomes and Process Evaluation Research (iHope International), Kyoto, Japan
| | - Yoshihiro Onishi
- Department of Pediatrics, Kobe City Medical Center General Hospital, Kobe, Japan
| | - Shingo Fukuma
- Department of Healthcare Epidemiology, School of Public Health in the Graduate School of Medicine, Kyoto University, Kyoto, Japan.,The Keihanshin Consortium for Fostering the Next Generation of Global Leaders in Research (K-CONNEX), Kyoto, Japan
| | - Shunichi Fukuhara
- Department of Healthcare Epidemiology, School of Public Health in the Graduate School of Medicine, Kyoto University, Kyoto, Japan.,Institute for Health Outcomes and Process Evaluation Research (iHope International), Kyoto, Japan
| | - Hideyuki Yamato
- Division of Nephrology, Endocrinology, and Metabolism, Tokai University School of Medicine, Isehara, Japan
| | - Masafumi Fukagawa
- Division of Nephrology, Endocrinology, and Metabolism, Tokai University School of Medicine, Isehara, Japan
| | - Tadao Akizawa
- Division of Nephrology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan
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8
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Ferreira SA, Young G, Jones JR, Rankin S. Bioglass/carbonate apatite/collagen composite scaffold dissolution products promote human osteoblast differentiation. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 118:111393. [PMID: 33254998 DOI: 10.1016/j.msec.2020.111393] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/10/2020] [Accepted: 08/12/2020] [Indexed: 12/30/2022]
Abstract
OssiMend® Bioactive (Collagen Matrix Inc., NJ) is a three-component porous composite bone graft device of 45S5 Bioglass/carbonate apatite/collagen. Our in vitro studies showed that conditioned media of the dissolution products of OssiMend Bioactive stimulated primary human osteoblasts to form mineralized bone-like nodules in vitro in one week, in basal culture media (no osteogenic supplements). Osteoblast differentiation was followed by gene expression analysis and a mineralization assay. In contrast, the dissolution products from commercial OssiMend (Bioglass-free carbonate apatite/collagen scaffolds), or from 45S5 Bioglass particulate alone, did not induce the mineralization of the extracellular matrix, but did induce osteoblast differentiation to mature osteoblasts, evidenced by the strong upregulation of BGLAP and IBSP mRNA levels. The calcium ions and soluble silicon species released from 45S5 Bioglass particles and additional phosphorus release from OssiMend mediated the osteostimulatory effects. Medium conditioned with OssiMend Bioactive dissolution had a much higher concentration of phosphorus and silicon than media conditioned with OssiMend and 45S5 Bioglass alone. While OssiMend and OssiMend Bioactive led to calcium precipitation in cell culture media, OssiMend Bioactive produced a higher concentration of soluble silicon than 45S5 Bioglass and higher dissolution of phosphorus than OssiMend. These in vitro results suggest that adding 45S5 Bioglass to OssiMend produces a synergistic osteostimulation effect on primary human osteoblasts. In summary, dissolution products of a Bioglass/carbonate apatite/collagen composite scaffold (OssiMend® Bioactive) stimulate human osteoblast differentiation and mineralization of extracellular matrix in vitro without any osteogenic supplements. The mineralization was faster than for dissolution products of ordinary Bioglass.
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Affiliation(s)
- Silvia A Ferreira
- National Heart & Lung Institute, Imperial College London, London, UK.
| | - Gloria Young
- Department of Materials, Imperial College London, London, UK.
| | - Julian R Jones
- Department of Materials, Imperial College London, London, UK.
| | - Sara Rankin
- National Heart & Lung Institute, Imperial College London, London, UK.
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9
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Abstract
Osteocytes are an ancient cell, appearing in fossilized skeletal remains of early fish and dinosaurs. Despite its relative high abundance, even in the context of nonskeletal cells, the osteocyte is perhaps among the least studied cells in all of vertebrate biology. Osteocytes are cells embedded in bone, able to modify their surrounding extracellular matrix via specialized molecular remodeling mechanisms that are independent of the bone forming osteoblasts and bone-resorbing osteoclasts. Osteocytes communicate with osteoclasts and osteoblasts via distinct signaling molecules that include the RankL/OPG axis and the Sost/Dkk1/Wnt axis, among others. Osteocytes also extend their influence beyond the local bone environment by functioning as an endocrine cell that controls phosphate reabsorption in the kidney, insulin secretion in the pancreas, and skeletal muscle function. These cells are also finely tuned sensors of mechanical stimulation to coordinate with effector cells to adjust bone mass, size, and shape to conform to mechanical demands.
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Affiliation(s)
- Alexander G Robling
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA;
| | - Lynda F Bonewald
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA;
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10
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Isolation of Murine and Human Osteocytes. Methods Mol Biol 2020. [PMID: 32979194 DOI: 10.1007/978-1-0716-0989-7_1] [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: 09/01/2023]
Abstract
Osteocytes are thought to be the mechanosensors of bone by sensing mechanical loads imposed upon the bone and transmitting these signals to the other bone cells to initiate bone modeling and remodeling. The location of osteocytes deep within bone is ideal for their function. However, this location makes the study of osteocytes in vivo technically difficult. There are several methods for obtaining and culturing primary osteocytes for in vitro experiments and ex vivo observation. In this chapter, several proven methods are discussed including the isolation of avian osteocytes from chicks and osteocytes from calvaria and long bones of young mice. A detailed protocol for the isolation of osteocytes from hypermineralized bone of mature and aged animals is provided. In addition, a modified version of this protocol that can be used to isolate osteocytes from human trabecular bone is described.
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11
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Simfia I, Schiavi J, McNamara LM. ROCK-II inhibition suppresses impaired mechanobiological responses in early estrogen deficient osteoblasts. Exp Cell Res 2020; 396:112264. [PMID: 32898551 DOI: 10.1016/j.yexcr.2020.112264] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/27/2020] [Accepted: 08/30/2020] [Indexed: 12/22/2022]
Abstract
Mechanobiological responses by osteoblasts are governed by downstream Rho-ROCK signalling through actin cytoskeleton re-arrangements but whether these responses are influenced by estrogen deficiency during osteoporosis remains unknown. The objective of this study was to determine alterations in the mechanobiological responses of estrogen-deficient osteoblasts and investigate whether an inhibitor of the Rho-ROCK signalling can revert these changes. MC3T3-E1 cells were pre-treated with 10 nM 17-β estradiol for 7 days and further cultured with or without estradiol for next 2 days. These cells were treated with or without ROCK-II inhibitor, Y-27632, and oscillatory fluid flow (OFF, 1Pa, 0.5 Hz, 1 h) was applied. Here, we report that Prostaglandin E2 release, Runt-related transcription factor 2 and Osteopontin gene expression were significantly enhanced in response to OFF in estrogen-deficient cells than in cells with estrogen (3.73 vs 1.63 pg/ng DNA; 13.5 vs 2.6 fold, 2.1 vs 0.4 fold respectively). Upon ROCK-II inhibition, these enhanced effects of estrogen deficiency were downregulated. OFF increased the fibril anisotropy in cells pre-treated with estrogen and this increase was suppressed upon ROCK-II inhibition. This study is the first to demonstrate altered mechanobiological responses by osteoblasts during early estrogen deficiency and that these responses to OFF can be suppressed upon ROCK inhibition.
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Affiliation(s)
- Irene Simfia
- Mechanobiology and Medical Device Research Group, Biomechanics Research Centre, Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
| | - Jessica Schiavi
- Mechanobiology and Medical Device Research Group, Biomechanics Research Centre, Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
| | - Laoise M McNamara
- Mechanobiology and Medical Device Research Group, Biomechanics Research Centre, Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland.
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12
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Naqvi SM, Panadero Pérez JA, Kumar V, Verbruggen ASK, McNamara LM. A Novel 3D Osteoblast and Osteocyte Model Revealing Changes in Mineralization and Pro-osteoclastogenic Paracrine Signaling During Estrogen Deficiency. Front Bioeng Biotechnol 2020; 8:601. [PMID: 32656194 PMCID: PMC7326002 DOI: 10.3389/fbioe.2020.00601] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 05/18/2020] [Indexed: 11/13/2022] Open
Abstract
Recent in vitro studies have revealed that the mechanobiological responses of osteoblasts and osteocytes are fundamentally impaired during estrogen deficiency. However, these two-dimensional (2D) cell culture studies do not account for in vivo biophysical cues. Thus, the objectives of this study are to (1) develop a three-dimensional (3D) osteoblast and osteocyte model integrated into a bioreactor and (2) apply this model to investigate whether estrogen deficiency leads to changes in osteoblast to osteocyte transition, mechanosensation, mineralization, and paracrine signaling associated with bone resorption by osteoclasts. MC3T3-E1s were expanded in media supplemented with estrogen (17β-estradiol). These cells were encapsulated in gelatin-mtgase before culture in (1) continued estrogen (E) or (2) no further estrogen supplementation. Constructs were placed in gas permeable and water impermeable cell culture bags and maintained at 5% CO2 and 37°C. These bags were either mechanically stimulated in a custom hydrostatic pressure (HP) bioreactor or maintained under static conditions (control). We report that osteocyte differentiation, characterized by the presence of dendrites and staining for osteocyte marker dentin matrix acidic phosphoprotein 1 (DMP1), was significantly greater under estrogen withdrawal (EW) compared to under continuous estrogen treatment (day 21). Mineralization [bone sialoprotein (BSP), osteopontin (OPN), alkaline phosphatase (ALP), calcium] and gene expression associated with paracrine signaling for osteoclastogenesis [receptor activator of nuclear factor kappa-β ligand (RANKL)/osteoprotegerin OPG ratio] were significantly increased in estrogen deficient and mechanically stimulated cells. Interestingly, BSP and DMP-1 were also increased at day 1 and day 21, respectively, which play a role in regulation of biomineralization. Furthermore, the increase in pro-osteoclastogenic signaling may be explained by altered mechanoresponsiveness of osteoblasts or osteocytes during EW. These findings highlight the impact of estrogen deficiency on bone cell function and provide a novel in vitro model to investigate the mechanisms underpinning changes in bone cells after estrogen deficiency.
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Affiliation(s)
| | | | | | | | - Laoise M. McNamara
- Mechanobiology and Medical Device Research Group, Department of Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
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13
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Enhancement of osteoblast cells osteogenic differentiation and bone regeneration by hydroxyapatite/phosphoester modified poly(amino acid). MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 111:110769. [PMID: 32279769 DOI: 10.1016/j.msec.2020.110769] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 01/27/2020] [Accepted: 02/21/2020] [Indexed: 12/14/2022]
Abstract
Hydroxyapatite/poly(amino acid) (HA/PAA) has been used to treat a variety of long bone and vertebral bony defects, and a further biocompatibility improvement is a key for better application. Phosphoester (PE) contained materials are highly biocompatible but could hardly treat massive bone defects due to its fast-degradation-derived mechanical instability. To address the problems of the two materials, we have incorporated PE molecule into the main chain of PAA by chemical bonding. As a result, the compressive strength of HA/PAA with 1 wt% and 2.5 wt% PE maintained in the range of 80-150 MPa after soaking in PBS for 12 weeks, which could be attributed to the amplified hydrogen-bonding inside composites. Besides, the PE-containing HA/PAAs with increased hydrophilic function groups (O=P-O bonds and O=P-N), created a more favourable surface for cell adhesion. Meanwhile, compared with HA/PAA, the PE-containing HA/PAAs had a fast minerlization speed and promoted cell osteogenic differentiation. Furthermore, the in vivo study indicated that PE-containing HA/PAAs could facilitate bone formation (4 weeks), and form a complete bone bridging (12 weeks) in a rabbit cranial bone defect. In summary, the HA/PE-m-PAAs possessed good mechanical stability, improved cytocompatibility and osteoconductivity, so the composites have a great potential for massive bone defect treatment.
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14
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Zhou Y, Lin J, Shao J, Zuo Q, Wang S, Wolff A, Nguyen DT, Rintoul L, Du Z, Gu Y, Peng YY, Ramshaw JAM, Long X, Xiao Y. Aberrant activation of Wnt signaling pathway altered osteocyte mineralization. Bone 2019; 127:324-333. [PMID: 31260814 DOI: 10.1016/j.bone.2019.06.027] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 06/27/2019] [Accepted: 06/27/2019] [Indexed: 12/20/2022]
Abstract
Mineralization of bone is a dynamic process, involving a complex interplay between cells, secreted macromolecules, signaling pathways, and enzymatic reactions; the dysregulation of bone mineralization may lead to serious skeletal disorders, including hypophosphatemic rickets, osteoporosis, and rheumatoid arthritis. Very few studies have reported the role of osteocytes - the most abundant bone cells in the skeletal system and the major orchestrators of bone remodeling in bone mineralization, which is owed to their nature of being deeply embedded in the mineralized bone matrix. The Wnt/β-catenin signaling pathway is actively involved in various life processes including osteogenesis; however, the role of Wnt/β-catenin signaling in the terminal mineralization of bone, especially in the regulation of osteocytes, is largely unknown. This research demonstrates that during the terminal mineralization process, the Wnt/β-catenin pathway is downregulated, and when Wnt/β-catenin signaling is activated in osteocytes, dendrite development is suppressed and the expression of dentin matrix protein 1 (DMP1) is inhibited. Aberrant activation of Wnt/β-catenin signaling in osteocytes leads to the spontaneous deposition of extra-large mineralized nodules on the surface of collagen fibrils. The altered mineral crystal structure and decreased bonding force between minerals and the organic matrix indicate the inferior integration of minerals and collagen. In conclusion, Wnt/β-catenin signaling plays a critical role in the terminal differentiation of osteocytes and as such, targeting Wnt/β-catenin signaling in osteocytes may serve as a potential therapeutic approach for the management of bone-related diseases.
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Affiliation(s)
- Yinghong Zhou
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia; Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 51050, China; School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia; The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia.
| | - Jinying Lin
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China; Department of Implantology, Affiliated Stomatological Hospital of Xiamen Medical College, Fujian 361000, China; The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia
| | - Jin Shao
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia; School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia; The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia.
| | - Qiliang Zuo
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China; Department of Implantology, Affiliated Stomatological Hospital of Xiamen Medical College, Fujian 361000, China; The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia
| | - Shengfang Wang
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia; School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia; The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia.
| | - Annalena Wolff
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia.
| | - Dung Trung Nguyen
- Department of Engineering and Computer Science, Seattle Pacific University, Seattle, WA 98119, USA.
| | - Llew Rintoul
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia.
| | - Zhibin Du
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia; School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia; The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia.
| | - Yuantong Gu
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia; The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia.
| | - Yong Y Peng
- CSIRO Manufacturing, Bayview Avenue, Clayton, VIC 3168, Australia.
| | - John A M Ramshaw
- CSIRO Manufacturing, Bayview Avenue, Clayton, VIC 3168, Australia
| | - Xing Long
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China; The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia.
| | - Yin Xiao
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China; Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia; Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 51050, China; School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia; The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia.
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15
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Alternating Differentiation and Dedifferentiation between Mature Osteoblasts and Osteocytes. Sci Rep 2019; 9:13842. [PMID: 31554848 PMCID: PMC6761144 DOI: 10.1038/s41598-019-50236-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 09/09/2019] [Indexed: 12/22/2022] Open
Abstract
Osteocytes are terminally differentiated osteoblasts embedded in the bone matrix. Evidence indicates that cells in the mesenchymal lineage possess plasticity. However, whether or not osteocytes have the capacity to dedifferentiate back into osteoblasts is unclear. This study aimed to clarify the dedifferentiation potential of osteocytes. Mouse calvarial osteoblasts were isolated and maintained in normal two-dimensional (2D) or collagen gel three-dimensional (3D) cultures. In 2D cultures, osteoblasts exhibited a typical fibroblast-like shape with high Alpl and minimal Sost, Fgf23, and Dmp1 expression and osteoblasts formed mineralised nodules. When these osteoblasts were transferred into 3D cultures, they showed a stellate shape with diminished cytoplasm and numerous long processes and expression of Alpl decreased while Sost, Fgf23, and Dmp1 were significantly increased. These cells were in cell cycle arrest and showed suppressed mineralisation, indicating that they were osteocytes. When these osteocytes were recovered from 3D cultures and cultured two-dimensionally again, they regained adequate cytoplasm and lost the long processes, resulting in a fibroblast-like shape. These cells showed high Alpl and low Sost, Fgf23, and Dmp1 expression with a high mineralisation capability, indicating that they were osteoblasts. This report shows that osteocytes possess the capacity to dedifferentiate back into mature osteoblasts without gene manipulation.
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16
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Abstract
PURPOSE OF REVIEW Osteocytes are responsible for mechanosensing and mechanotransduction in bone and play a crucial role in bone homeostasis. They are embedded in a calcified collagenous matrix and connected with each other through the lacuno-canalicular network. Due to this specific native environment, it is a challenge to isolate primary osteocytes without losing their specific characteristics in vitro. This review summarizes the commonly used and recently established models to study the function of osteocytes in vitro. RECENT FINDINGS Osteocytes are mostly studied in monolayer culture, but recently, 3D models of osteocyte-like cells and primary osteocytes in vitro have been established as well. These models mimic the native environment of osteocytes and show superior osteocyte morphology and behavior, enabling the development of human disease models. Osteocyte-like cell lines as well as primary osteocytes isolated from bone are widely used to study the role of osteocytes in bone homeostasis. Both cells lines and primary cells are cultured in 2D-monolayer and 3D-models. The use of these models and their advantages and shortcomings are discussed in this review.
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Affiliation(s)
- Chen Zhang
- Department of Oral Cell Biology, Amsterdam Movement Sciences, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Department of Clinical Chemistry, Amsterdam Movement Sciences, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Astrid D Bakker
- Department of Oral Cell Biology, Amsterdam Movement Sciences, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Jenneke Klein-Nulend
- Department of Oral Cell Biology, Amsterdam Movement Sciences, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Nathalie Bravenboer
- Department of Clinical Chemistry, Amsterdam Movement Sciences, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
- Department of Internal Medicine, Division of Endocrinology and Center for Bone Quality, Leiden University Medical Center, Leiden, The Netherlands.
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17
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Werner SL, Sharma R, Woodruff K, Horn D, Harris SE, Gorin Y, Lee DY, Hua R, Gu S, Fajardo RJ, Habib SL, Jiang JX. CSF-1 in Osteocytes Inhibits Nox4-mediated Oxidative Stress and Promotes Normal Bone Homeostasis. JBMR Plus 2019; 4:e10080. [PMID: 32666016 DOI: 10.1002/jbm4.10080] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 08/28/2018] [Accepted: 08/30/2018] [Indexed: 12/12/2022] Open
Abstract
CSF-1 is a key factor in regulating bone remodeling; osteocytes express CSF-1 and its receptor. Viable osteocytes are essential for bone remodeling through cell-cell contact and secretion of factors that regulate osteoblasts and osteoclasts. Increased oxidative stress contributes to osteocyte death and correlates with bone loss during aging. The NADPH oxidase Nox4 is a major source of ROS in bone. CSF-1 decreases Nox4, suggesting that CSF-1 protects against oxidative stress. Here, we show that osteocyte apoptosis previously reported in our global CSF-1KO mice is associated with increased Nox4, as well as 4-HNE expression in osteocytes. Osteocytes isolated from CSF-1KO mice were less viable and showed increased intracellular ROS, elevated NADPH oxidase activity/Nox4 protein, activation of mTOR/S6K, and downstream apoptosis signals compared with WT osteocytes. Nox4 expression was also increased in CSF-1KO osteocytes and colocalized with MitoTracker Red in mitochondria. Notably, CSF-1 inhibited Nox4 expression and apoptosis cascade signals. In additional studies, shNox4 decreased these signals in CSF-1KO osteocytes, whereas overexpression of Nox4 in WT osteocytes activated the apoptosis pathway. To determine the role of CSF-1 in osteocytes, DMP1Cre-CSF-1cKO (CSF-1cKO) mice that lack CSF-1 in osteocytes/late osteoblasts were developed. Osteocyte defects in CSF-1cKO mice overlapped with those in CSF-1KO mice, including increased apoptosis, Nox4, and 4-HNE-expressing osteocytes. CSF-1cKO mice showed unbalanced cancellous bone remodeling with decreased bone formation and resorption. Continued exposure to high Nox4/ROS levels may further compromise bone formation and predispose to bone loss and skeletal fragility. Taken together, our findings suggest a novel link between CSF-1, Nox4-derived ROS, and osteocyte survival/function that is crucial for osteocyte-mediated bone remodeling. Results reveal new mechanisms by which CSF-1/oxidative stress regulate osteocyte homeostasis, which may lead to therapeutic strategies to improve skeletal health in aging. © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
- Sherry L Werner
- Department of Pathology University of Texas Health Science Center at San Antonio TX USA
| | - Ramaswamy Sharma
- Department of Cell Systems and Anatomy University of Texas Health Science Center at San Antonio TX USA
| | - Kathleen Woodruff
- Department of Pathology University of Texas Health Science Center at San Antonio TX USA
| | - Diane Horn
- Department of Pathology University of Texas Health Science Center at San Antonio TX USA
| | - Stephen E Harris
- Department of Periodontics University of Texas Health Science Center at San Antonio TX USA
| | - Yves Gorin
- Department of Medicine/Nephrology University of Texas Health Science Center at San Antonio TX USA
| | - Doug-Yoon Lee
- Department of Medicine/Nephrology University of Texas Health Science Center at San Antonio TX USA
| | - Rui Hua
- Department of Biochemistry and Structural Biology University of Texas Health Science Center at San Antonio TX USA
| | - Sumin Gu
- Department of Biochemistry and Structural Biology University of Texas Health Science Center at San Antonio TX USA
| | - Roberto J Fajardo
- Department of Orthopedics University of Texas Health Science Center at San Antonio TX USA
| | - Samy L Habib
- South Texas Veterans Health Care and Department of Cell Systems and Anatomy University of Texas Health Science Center at San Antonio TX USA
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology University of Texas Health Science Center at San Antonio TX USA
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18
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Liu H, Yang M, Wu G, Yang L, Cao Y, Liu C, Tan Z, Jin Y, Guo J, Zhu L. Effects of different oxygen concentrations on the proliferation, survival, migration, and osteogenic differentiation of MC3T3-E1 cells. Connect Tissue Res 2019; 60:240-253. [PMID: 29916278 DOI: 10.1080/03008207.2018.1487413] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In physiological and pathological environments, the concentration of oxygen around osteoblasts varies widely. No studies have systematically evaluated the effects of different oxygen concentrations on the proliferation, survival, migration, and osteogenic differentiation of osteoblasts. In this study, we cultured the osteoblast precursor cell line MC3T3-E1 in small individual chambers with oxygen concentrations of 1%, 3%, 6%, 9%, and 21%. Cell proliferation was evaluated by the proliferation index test and EdU staining. To test cell survival, a live/dead assay was performed. A tablet scratch assay was performed to detect the migratory ability of the cells. Bone nodule formation experiments and immunofluorescence and Western blotting analyses of osteogenic-related proteins were performed to assess the osteogenic differentiation of the cells. We found that the proliferation and osteogenic differentiation ability of MC3T3-E1 cells in different oxygen concentrations were both approximately bell-shaped curves and that the optimal oxygen concentrations were approximately 6% and 9%, respectively. The live/dead assay showed that the survival of MC3T3-E1 cells in different oxygen concentrations was affected by the amount of serum. The tablet scratch experiment showed that there was greater cell migration with oxygen concentrations of 1%, 3%, and 21% than with oxygen concentrations of 6% and 9%. Our results have significant reference value for the intervention of the pathological processes involving osteoblasts, such as fracture, osteoporosis, and some vascular diseases. These results also have an important guiding role for the new scientific idea that osteoblasts can function as treatment cells to repair bone defects.
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Affiliation(s)
- Haixin Liu
- a Department of Spine Orthopedics , Zhujiang Hospital, Southern Medical University , Guangzhou , China
| | - Minsheng Yang
- a Department of Spine Orthopedics , Zhujiang Hospital, Southern Medical University , Guangzhou , China
| | - Guofeng Wu
- b Department of Orthopedics , Jingzhou First People's Hospital, The First Affiliated Hospital of Yangtze University , Jingzhou , China
| | - Lianjun Yang
- c Department of Spine Orthopedics , The Third Affiliated Hospital, Southern Medical University , Guangzhou , China
| | - Yanlin Cao
- a Department of Spine Orthopedics , Zhujiang Hospital, Southern Medical University , Guangzhou , China
| | - Chun Liu
- a Department of Spine Orthopedics , Zhujiang Hospital, Southern Medical University , Guangzhou , China
| | - Zhiwen Tan
- a Department of Spine Orthopedics , Zhujiang Hospital, Southern Medical University , Guangzhou , China
| | - Yanglei Jin
- a Department of Spine Orthopedics , Zhujiang Hospital, Southern Medical University , Guangzhou , China
| | - Jiasong Guo
- d Department of Histology and Embryology , Southern Medical University , Guangzhou , China.,e Key Laboratory of Tissue Construction and Detection of Guangdong Province , Guangzhou , China.,f Institute of Bone Biology, Academy of Orthopaedics, Guangdong Province , Guangzhou , China
| | - Lixin Zhu
- a Department of Spine Orthopedics , Zhujiang Hospital, Southern Medical University , Guangzhou , China
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19
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Gooi JH, Chia LY, Vrahnas C, Sims NA. Isolation, Purification, Generation, and Culture of Osteocytes. Methods Mol Biol 2019; 1914:39-51. [PMID: 30729459 DOI: 10.1007/978-1-4939-8997-3_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Osteocytes reside within bone matrix and produce both paracrine and endocrine factors that influence the skeleton and other tissues. Despite their abundance and physiological importance, osteocytes have been difficult to study in vitro because they are difficult to extract and purify, and do not retain their phenotype in standard culture conditions. However, new techniques for this purpose are emerging. This chapter will describe three methods we use to study osteocytes: (1) isolating and purifying primary osteocytes from murine bone, with and without hematopoietic-lineage depletion, (2) differentiating cultured osteoblasts (or osteoblast cell lines) until they reach a stage of osteocytic gene expression, and (3) using the Ocy454 osteocyte-like cell line.
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Affiliation(s)
- Jonathan H Gooi
- Department of Medicine, St. Vincent's Hospital Melbourne, The University of Melbourne, Melbourne, VIC, Australia
| | - Ling Yeong Chia
- Department of Medicine, St. Vincent's Hospital Melbourne, The University of Melbourne, Melbourne, VIC, Australia
- St. Vincent's Institute of Medical Research, Melbourne, VIC, Australia
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Clayton, VIC, Australia
| | - Christina Vrahnas
- Department of Medicine, St. Vincent's Hospital Melbourne, The University of Melbourne, Melbourne, VIC, Australia
- St. Vincent's Institute of Medical Research, Melbourne, VIC, Australia
- MRC Protein Phosphorylation & Ubiquitylation Unit, University of Dundee, Sir James Black Centre, Dundee, UK
| | - Natalie A Sims
- Department of Medicine, St. Vincent's Hospital Melbourne, The University of Melbourne, Melbourne, VIC, Australia.
- St. Vincent's Institute of Medical Research, Melbourne, VIC, Australia.
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20
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Iijima K, Ishikawa S, Sasaki K, Hashizume M, Kawabe M, Otsuka H. Osteogenic Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells in Electrospun Silica Nonwoven Fabrics. ACS OMEGA 2018; 3:10180-10187. [PMID: 31459146 PMCID: PMC6645240 DOI: 10.1021/acsomega.8b01139] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/20/2018] [Indexed: 05/12/2023]
Abstract
Silica nonwoven fabrics (SNFs) with enough mechanical strength are candidates as implantable scaffolds. Culture of cells therein is expected to affect the proliferation and differentiation of the cells through cell-cell and cell-SNF interactions. In this study, we examined three-dimensional (3D) SNFs as a scaffold of mesenchymal stem cells (MSCs) for bone tissue engineering applications. The interconnected highly porous microstructure of 3D SNFs is expected to allow omnidirectional cell-cell interactions, and the morphological similarity of a silica nanofiber to that of a fibrous extracellular matrix can contribute to the promotion of cell functions. 3D SNFs were prepared by the sol-gel process, and their mechanical properties were characterized by the compression test and rheological analysis. In the compression test, SNFs showed a compressive elastic modulus of over 1 MPa and a compressive strength of about 200 kPa. These values are higher than those of porous polystyrene disks used for in vitro 3D cell culture. In rheological analysis, the elastic modulus and fracture stress were 3.27 ± 0.54 kPa and 25.9 ± 8.3 Pa, respectively. Then, human bone marrow-derived MSCs were cultured on SNFs, and the effects on proliferation and osteogenic differentiation were evaluated. The MSCs seeded on SNF proliferated, and the thickness of the cell layer became over 80 μm after 14 days of culture. The osteogenic differentiation of MSCs on SNFs was induced by the culture in the commercial osteogenic differentiation medium. The alkaline phosphatase activity of MSCs on SNFs increased rapidly and remained high up to 14 days and was much higher than that on two-dimensional tissue culture-treated polystyrene. The high expression of RUNX2 and intense staining by alizarin red s after differentiation supported that SNFs enhanced the osteogenic differentiation of MSCs. Furthermore, permeation analysis of SNFs using fluorescein isothiocyanate-dextran suggested a sufficient permeability of SNFs for oxygen, minerals, nutrients, and secretions, which is important for maintaining the cell viability and vitality. These results suggested that SNFs are promising scaffolds for the regeneration of bone defects using MSCs, originated from highly porous and elastic SNF characters.
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Affiliation(s)
- Kazutoshi Iijima
- Department
of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, 12-1 Ichigayafunagawara-machi,
Shinjuku-ku, Tokyo 162-0826, Japan
| | - Shohei Ishikawa
- Graduate School of Science and Department of
Applied Chemistry, Faculty of
Science, Tokyo University of Science, 1-3 Kagurazaka,
Shinjuku-ku, Tokyo 162-8601, Japan
| | - Kohei Sasaki
- Japan
Vilene Company Ltd., 7 kita-Tone, Koga, Ibaraki 306-0213, Japan
| | - Mineo Hashizume
- Department
of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, 12-1 Ichigayafunagawara-machi,
Shinjuku-ku, Tokyo 162-0826, Japan
| | - Masaaki Kawabe
- Japan
Vilene Company Ltd., 7 kita-Tone, Koga, Ibaraki 306-0213, Japan
| | - Hidenori Otsuka
- Graduate School of Science and Department of
Applied Chemistry, Faculty of
Science, Tokyo University of Science, 1-3 Kagurazaka,
Shinjuku-ku, Tokyo 162-8601, Japan
- E-mail: . Phone: +81-3-5228-8265. Fax: +81-3-5261-4631 (H.O.)
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21
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IGF-I induced phosphorylation of PTH receptor enhances osteoblast to osteocyte transition. Bone Res 2018; 6:5. [PMID: 29507819 PMCID: PMC5827661 DOI: 10.1038/s41413-017-0002-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 04/25/2017] [Accepted: 05/02/2017] [Indexed: 02/05/2023] Open
Abstract
Parathyroid hormone (PTH) regulates bone remodeling by activating PTH type 1 receptor (PTH1R) in osteoblasts/osteocytes. Insulin-like growth factor type 1 (IGF-1) stimulates mesenchymal stem cell differentiation to osteoblasts. However, little is known about the signaling mechanisms that regulates the osteoblast-to-osteocyte transition. Here we report that PTH and IGF-I synergistically enhance osteoblast-to-osteocyte differentiation. We identified that a specific tyrosine residue, Y494, on the cytoplasmic domain of PTH1R can be phosphorylated by insulin-like growth factor type I receptor (IGF1R) in vitro. Phosphorylated PTH1R localized to the barbed ends of actin filaments and increased actin polymerization during morphological change of osteoblasts into osteocytes. Disruption of the phosphorylation site reduced actin polymerization and dendrite length. Mouse models with conditional ablation of PTH1R in osteoblasts demonstrated a reduction in the number of osteoctyes and dendrites per osteocyte, with complete overlap of PTH1R with phosphorylated-PTH1R positioning in osteocyte dendrites in wild-type mice. Thus, our findings reveal a novel signaling mechanism that enhances osteoblast-to-osteocyte transition by direct phosphorylation of PTH1R by IGF1R. A key hormone and growth factor work together to help turn bone-forming cells into mature bone. Janet Crane and colleagues from Johns Hopkins University School of Medicine in Baltimore, Maryland, USA, tested the effects of parathyroid hormone (PTH) and insulin like-growth factor type 1 (IGF-1) signaling on the differentiation of bone-forming osteoblasts by modulating the activity of their receptors in genetically engineered mice. They found a specific part of the PTH type 1 receptor has a phosphate group added to it by the IGF-1 receptor. This chemical tagging leads to changes in the cytoskeleton of osteoblasts that enhance the formation of mature bone cells known as osteocytes. Mice without this PTH receptor had reduced numbers of osteocytes in their bone. The findings reveal a novel signaling mechanism behind this cellular transition during bone building.
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Shao J, Zhou Y, Lin J, Nguyen TD, Huang R, Gu Y, Friis T, Crawford R, Xiao Y. Notch expressed by osteocytes plays a critical role in mineralisation. J Mol Med (Berl) 2018; 96:333-347. [PMID: 29455246 DOI: 10.1007/s00109-018-1625-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 01/04/2018] [Accepted: 02/05/2018] [Indexed: 12/21/2022]
Abstract
Notch is actively involved in various life processes including osteogenesis; however, the role of Notch signalling in the terminal mineralisation of bone is largely unknown. In this study, it was noted that Hey1, a downstream target of Notch signalling was highly expressed in mature osteocytes compared to osteoblasts, indicating a potential role of Notch in osteocytes. Using a recently developed thermosensitive cell line (IDG-SW3), we demonstrated that dentin matrix acidic phosphoprotein 1 (DMP1) expression was inhibited and mineralisation process was significantly altered when Notch pathway was inactivated via administration of N-[N-(3,5-Difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT), an inhibitor of Notch. Dysregulation of Notch in osteocyte differentiation can result in spontaneous deposition of calcium phosphate on collagen fibrils, disturbed transportation of intracellular mineral vesicles, alteration of mineral crystal structure, decreased bonding force between minerals and organic matrix, and suppression of dendrite development coupled with decreased expression of E11. In conclusion, the evidence presented here suggests that Notch plays a critical role in osteocyte differentiation and biomineralisation process. KEY MESSAGES Notch plays a regulatory role in osteocyte phenotype. Notch modulates the mineralisation mediated by osteocytes. Notch activity influences the ultrastructural properties of bone mineralisation.
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Affiliation(s)
- Jin Shao
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, QLD, 4059, Australia
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Yinghong Zhou
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, QLD, 4059, Australia
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Jinying Lin
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia
- Department of Implantology, Xiamen Stomatological Research Institute, Xiamen Stomatological Hospital, Fujian, 361000, China
| | - Trung Dung Nguyen
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, 4059, Australia
- Department of Aerospace and Mechanical Engineering, College of Engineering, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Rong Huang
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, QLD, 4059, Australia
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Yuantong Gu
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Thor Friis
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, QLD, 4059, Australia
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Ross Crawford
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, QLD, 4059, Australia
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia
- The Prince Charles Hospital, Brisbane, QLD, 4059, Australia
| | - Yin Xiao
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, QLD, 4059, Australia.
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia.
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23
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Chen X, Wang L, Zhao K, Wang H. Osteocytogenesis: Roles of Physicochemical Factors, Collagen Cleavage, and Exogenous Molecules. TISSUE ENGINEERING PART B-REVIEWS 2018; 24:215-225. [PMID: 29304315 DOI: 10.1089/ten.teb.2017.0378] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Osteocytes, the most abundant cell type in mammalian bone, are generally considered as the terminally differentiated cells of osteoblasts that are progressively self-buried or passively embedded in bone matrix. Emerging evidence reveals the essential functions of osteocytes in bone homeostasis and mechanotransduction. However, our knowledge on osteocytes, especially their formation, remains scarce. In this regard, the current review mainly focuses on several key factors that drive the osteocytic differentiation of osteoblasts, that is, osteocytogenesis. Available literature has demonstrated the involvement of physicochemical factors such as matrix composition, oxygen tension, and mechanical stress in the osteoblast-to-osteocyte transition. During cell migration and matrix remodeling, the matrix metalloproteinase-dependent collagen cleavage would play an "active" role in maturation and maintenance of the osteocytes. Besides, some in vitro methodologies are also established to induce the transformation of osteoblastic cell lines and primary mesenchymal cells to preosteocytes through cell transfection or addition of exogenous molecules (e.g., fibroblast growth factor-2, retinoic acid), which could potentiate the effort to form functional bone substitutes through elevated osteocytogenesis. Thus, advances of new technologies would enable comprehensive and in-depth understanding of osteocytes and their development, which in turn help promote the research on osteocyte biology and osteopathology.
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Affiliation(s)
- Xuening Chen
- 1 National Engineering Research Center for Biomaterials, Sichuan University , Chengdu, China
| | - Lichen Wang
- 2 Department of Biomedical Engineering, Chemistry and Biological Sciences, Stevens Institute of Technology , Hoboken, New Jersey
| | - Kaitao Zhao
- 2 Department of Biomedical Engineering, Chemistry and Biological Sciences, Stevens Institute of Technology , Hoboken, New Jersey
| | - Hongjun Wang
- 2 Department of Biomedical Engineering, Chemistry and Biological Sciences, Stevens Institute of Technology , Hoboken, New Jersey
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24
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Oya K, Ishida K, Nishida T, Sato S, Kishino M, Hirose K, Ogawa Y, Ikebe K, Takeshige F, Yasuda H, Komori T, Toyosawa S. Immunohistochemical analysis of dentin matrix protein 1 (Dmp1) phosphorylation by Fam20C in bone: implications for the induction of biomineralization. Histochem Cell Biol 2016; 147:341-351. [PMID: 27614627 DOI: 10.1007/s00418-016-1490-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2016] [Indexed: 01/03/2023]
Abstract
Dmp1 is an acidic phosphoprotein that is specifically expressed in osteocytes. During the secretory process, the full-length, precursor Dmp1 is cleaved into N- and C-terminal fragments. C-terminal Dmp1 is phosphorylated, becoming a highly negatively charged domain that may assist in bone mineralization by recruiting calcium ions and influencing subsequent mineral deposition. It has been recently reported that the Golgi-localized protein kinase Fam20C phosphorylates Dmp1 in vitro. To investigate this phosphorylation in situ, we determined the locations of phosphorylated Dmp1 and Fam20C in rat bones using immunohistochemistry. During osteocytogenesis, osteoblastic, osteoid, and young osteocytes (but not old osteocytes) express Dmp1 mRNA and contain Dmp1 protein in the Golgi apparatus. These Dmp1-producing cells were distributed across the surface layer of cortical bone. Using immunofluorescence, we found that N- and C-terminal Dmp1 fragments were predominantly distributed along the lacunar walls and canaliculi of mineralized bone, respectively, but were not present in the osteoid matrix. We also found that Fam20C and its substrate, C-terminal Dmp1, colocalized in the Golgi of osteoblastic, osteoid, and young osteocytes. Furthermore, phosphorylated C-terminal Dmp1 was present in the Golgi of young osteocytes. Double-labeling immunoelectron microscopy revealed that phosphorylated C-terminal Dmp1 localized to the canalicular wall in mineralized bone. These findings suggest that C-terminal Dmp1 is phosphorylated within osteocytes and then secreted into the pericanalicular matrix of mineralized bone. Phosphorylated, negatively charged C-terminal Dmp1 in the pericanalicular matrix may play an important role in bone mineralization by recruiting calcium ions.
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Affiliation(s)
- Kaori Oya
- Department of Oral Pathology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Division for Interdisciplinary Dentistry, Osaka University Dental Hospital, Suita, Osaka, Japan
| | - Ken Ishida
- Department of Oral Pathology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Department of Prosthodontics and Oral Rehabilitation, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
| | - Tomoki Nishida
- Reserch Center for Ultra-High Voltage Electron Microscopy, Osaka University, Ibaraki, Osaka, Japan
| | - Sunao Sato
- Department of Oral Pathology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Mitsunobu Kishino
- Department of Oral Pathology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Katsutoshi Hirose
- Department of Oral Pathology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yuzo Ogawa
- Department of Oral Pathology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Kazunori Ikebe
- Department of Prosthodontics and Oral Rehabilitation, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
| | - Fumio Takeshige
- Division for Interdisciplinary Dentistry, Osaka University Dental Hospital, Suita, Osaka, Japan
| | - Hidehiro Yasuda
- Reserch Center for Ultra-High Voltage Electron Microscopy, Osaka University, Ibaraki, Osaka, Japan
| | - Toshihisa Komori
- Department of Cell Biology, Unit of Basic Medical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Satoru Toyosawa
- Department of Oral Pathology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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25
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Liu DM, Zhao L, Liu TT, Jiao PL, Zhao DD, Shih MS, Tao B, Sun LH, Zhao HY, Liu JM. Rictor/mTORC2 loss in osteoblasts impairs bone mass and strength. Bone 2016; 90:50-8. [PMID: 27262777 DOI: 10.1016/j.bone.2016.05.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 05/25/2016] [Accepted: 05/29/2016] [Indexed: 11/26/2022]
Abstract
Mammalian target of rapamycin (mTOR) is a Ser/Thr kinase conserved through evolution that coordinates extra cellular signals associated with cell growth. Main functions of mTOR present in the form of two complexes, namely mTORC1 and mTORC2, which are distinct in their unique components, raptor and rictor. In the current study, using a Cre/loxp system, we found an anabolic effect of mTORC2 signaling on skeleton. Osteoblast differentiation was reduced, with down-regulation of mTORC2 signaling activity in primary cultures of osteoblasts that did not contain rictor. Mice with a specific deletion of rictor in mature osteoblasts showed a significant reduction in lean mass and bone mineral density by dual energy x-ray absorptiometry analysis. Micro-computed tomography, histomorphometric, and molecular biological analyses revealed a marked impairment of the cortical bone mass and microarchitecture, as well as minor changes in trabecular bone, of the Rictorob(-/-) mice. Cortical bone mass and thickness of the femoral mid-shaft were dramatically reduced, with unusual increases in porosity and marrow area in Rictorob(-/-) mice. Thinner trabeculae were found in the L4 vertebrae with relatively normal structural indices of trabecular numbers and separation. A lower rate of bone turnover was observed, as the consequence of the decreased individual osteoblast activity and bone resorption. Furthermore, these changes were associated with significantly decreased bone biomechanical properties. In conclusion, expression of rictor in osteoblasts is essential for the maintenance of normal bone remodeling and microarchitecture, especially for the maintenance of the cortical bone.
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Affiliation(s)
- Dong-Mei Liu
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Lin Zhao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China; Department of Endocrine and Metabolic Diseases, ZhongShan Hospital, FuDan University, Shanghai, China
| | - Ting-Ting Liu
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Pei-Lin Jiao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Dian-Dian Zhao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Mei-Shu Shih
- PharmaLegacy Laboratories Co., Ltd., Shanghai, China
| | - Bei Tao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Li-Hao Sun
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Hong-Yan Zhao
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
| | - Jian-Min Liu
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China.
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26
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Iijima K, Suzuki R, Iizuka A, Ueno-Yokohata H, Kiyokawa N, Hashizume M. Surface functionalization of tissue culture polystyrene plates with hydroxyapatite under body fluid conditions and its effect on differentiation behaviors of mesenchymal stem cells. Colloids Surf B Biointerfaces 2016; 147:351-359. [PMID: 27559995 DOI: 10.1016/j.colsurfb.2016.08.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 08/10/2016] [Accepted: 08/17/2016] [Indexed: 11/28/2022]
Abstract
The surfaces of polystyrene (PS) cell culture plates were functionalized with hydroxyapatite (HAp) under body fluid conditions utilizing protein adsorption layers and a pretreatment with an alternate soaking process (ASP) using solutions containing calcium and phosphate ions. Adsorption layers of human serum albumin (HSA) formed on the surface of each well of commercial 24-well PS plates by solution processes. CaCl2 and K2HPO4 solutions were alternately added to the wells, the plates were incubated to form the precursors, and this was followed by the addition of simulated body fluid (SBF) and a further incubation for 24h. These treatments resulted in the surfaces of the PS cell culture plates being completely covered with bone-like HAp. The coating of PS plates with HAp promoted the adhesion of mesenchymal stem cells (MSCs) and maintained cell growth that was as fast as that on tissue culture-treated PS (TCPS) plates. Osteogenic differentiation was greater, whereas adipogenic and chondrogenic differentiation was less in the culture on HAp-coated PS plates than in that on TCPS plates. The present method is useful for preparing HAp-coated PS plates at clean benches without the need for any expensive apparatus. HAp coated on PS plates by this method was a bone-like apatite with high bioactivity; therefore, the present HAp-coated PS plates are promising materials for assays of bone-related cells in the bone remodeling process.
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Affiliation(s)
- Kazutoshi Iijima
- Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, 12-1 Ichigayafunagawara-machi, Shinjuku-ku, Tokyo 162-0826, Japan; Graduate School of Chemical Sciences and Technology, Tokyo University of Science, 12-1 Ichigayafunagawara-machi, Shinjuku-ku, Tokyo 162-0826, Japan
| | - Ryo Suzuki
- Graduate School of Chemical Sciences and Technology, Tokyo University of Science, 12-1 Ichigayafunagawara-machi, Shinjuku-ku, Tokyo 162-0826, Japan
| | - Ayako Iizuka
- Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, 12-1 Ichigayafunagawara-machi, Shinjuku-ku, Tokyo 162-0826, Japan
| | - Hitomi Ueno-Yokohata
- Department of Pediatric Hematology and Oncology Research, National Research Institute for Child Health and Development, 2-10-1, Okura, Setagaya-ku, Tokyo 157-8535, Japan
| | - Nobutaka Kiyokawa
- Department of Pediatric Hematology and Oncology Research, National Research Institute for Child Health and Development, 2-10-1, Okura, Setagaya-ku, Tokyo 157-8535, Japan
| | - Mineo Hashizume
- Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, 12-1 Ichigayafunagawara-machi, Shinjuku-ku, Tokyo 162-0826, Japan; Graduate School of Chemical Sciences and Technology, Tokyo University of Science, 12-1 Ichigayafunagawara-machi, Shinjuku-ku, Tokyo 162-0826, Japan.
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27
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Murali SK, Andrukhova O, Clinkenbeard EL, White KE, Erben RG. Excessive Osteocytic Fgf23 Secretion Contributes to Pyrophosphate Accumulation and Mineralization Defect in Hyp Mice. PLoS Biol 2016; 14:e1002427. [PMID: 27035636 PMCID: PMC4818020 DOI: 10.1371/journal.pbio.1002427] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 03/08/2016] [Indexed: 11/24/2022] Open
Abstract
X-linked hypophosphatemia (XLH) is the most frequent form of inherited rickets in humans caused by mutations in the phosphate-regulating gene with homologies to endopeptidases on the X-chromosome (PHEX). Hyp mice, a murine homologue of XLH, are characterized by hypophosphatemia, inappropriately low serum vitamin D levels, increased serum fibroblast growth factor-23 (Fgf23), and osteomalacia. Although Fgf23 is known to be responsible for hypophosphatemia and reduced vitamin D hormone levels in Hyp mice, its putative role as an auto-/paracrine osteomalacia-causing factor has not been explored. We recently reported that Fgf23 is a suppressor of tissue nonspecific alkaline phosphatase (Tnap) transcription via FGF receptor-3 (FGFR3) signaling, leading to inhibition of mineralization through accumulation of the TNAP substrate pyrophosphate. Here, we report that the pyrophosphate concentration is increased in Hyp bones, and that Tnap expression is decreased in Hyp-derived osteocyte-like cells but not in Hyp-derived osteoblasts ex vivo and in vitro. In situ mRNA expression profiling in bone cryosections revealed a ~70-fold up-regulation of Fgfr3 mRNA in osteocytes versus osteoblasts of Hyp mice. In addition, we show that blocking of increased Fgf23-FGFR3 signaling with anti-Fgf23 antibodies or an FGFR3 inhibitor partially restored the suppression of Tnap expression, phosphate production, and mineralization, and decreased pyrophosphate concentration in Hyp-derived osteocyte-like cells in vitro. In vivo, bone-specific deletion of Fgf23 in Hyp mice rescued the suppressed TNAP activity in osteocytes of Hyp mice. Moreover, treatment of wild-type osteoblasts or mice with recombinant FGF23 suppressed Tnap mRNA expression and increased pyrophosphate concentrations in the culture medium and in bone, respectively. In conclusion, we found that the cell autonomous increase in Fgf23 secretion in Hyp osteocytes drives the accumulation of pyrophosphate through auto-/paracrine suppression of TNAP. Hence, we have identified a novel mechanism contributing to the mineralization defect in Hyp mice. A novel mechanism involving autocrine and paracrine actions of fibroblast growth factor-23 contributes to the mineralization defect observed in Hyp, a mouse model for X-linked hypophosphatemia. X-linked hypophosphatemia (XLH) is the most frequent form of inherited rickets in humans. A mouse model of XLH, known as Hyp, is characterized by exceptionally low serum phosphate and vitamin D levels, increased serum levels of the hormone fibroblast growth factor-23 (Fgf23), and impaired bone mineralization. Fgf23 is secreted from two classes of bone cells known as osteoblasts and osteocytes. Fgf23 increases urinary phosphate excretion and suppresses vitamin D hormone production in the kidney. Although Fgf23 is known to be responsible for lower blood phosphate and vitamin D hormone levels in Hyp mice, its putative role as a signaling factor causing impaired mineralization has not been explored. We recently reported that Fgf23 is a suppressor of tissue nonspecific alkaline phosphatase (Tnap) gene expression via FGF receptor-3 (FGFR3) signaling in osteoblasts, leading to inhibition of mineralization through accumulation of the TNAP substrate pyrophosphate. Pyrophosphate is a potent inhibitor of mineralization. Using a combination of cell culture and animal models, we report that the increase in osteocyte Fgf23 secretion of Hyp mice leads to FGFR3-mediated suppression of TNAP with subsequent accumulation of pyrophosphate. Hence, we have identified a novel signaling mechanism by which excessive osteocytic secretion of Fgf23 contributes to the mineralization defect in Hyp mice.
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Affiliation(s)
- Sathish K. Murali
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Olena Andrukhova
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Erica L. Clinkenbeard
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Kenneth E. White
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Reinhold G. Erben
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
- * E-mail:
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28
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Namkoong B, Güven S, Ramesan S, Liaudanskaya V, Abzhanov A, Demirci U. Recapitulating cranial osteogenesis with neural crest cells in 3-D microenvironments. Acta Biomater 2016; 31:301-311. [PMID: 26675129 DOI: 10.1016/j.actbio.2015.12.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 11/11/2015] [Accepted: 12/02/2015] [Indexed: 01/20/2023]
Abstract
The experimental systems that recapitulate the complexity of native tissues and enable precise control over the microenvironment are becoming essential for the pre-clinical tests of therapeutics and tissue engineering. Here, we described a strategy to develop an in vitro platform to study the developmental biology of craniofacial osteogenesis. In this study, we directly osteo-differentiated cranial neural crest cells (CNCCs) in a 3-D in vitro bioengineered microenvironment. Cells were encapsulated in the gelatin-based photo-crosslinkable hydrogel and cultured up to three weeks. We demonstrated that this platform allows efficient differentiation of p75 positive CNCCs to cells expressing osteogenic markers corresponding to the sequential developmental phases of intramembranous ossification. During the course of culture, we observed a decrease in the expression of early osteogenic marker Runx2, while the other mature osteoblast and osteocyte markers such as Osterix, Osteocalcin, Osteopontin and Bone sialoprotein increased. We analyzed the ossification of the secreted matrix with alkaline phosphatase and quantified the newly secreted hydroxyapatite. The Field Emission Scanning Electron Microscope (FESEM) images of the bioengineered hydrogel constructs revealed the native-like osteocytes, mature osteoblasts, and cranial bone tissue morphologies with canaliculus-like intercellular connections. This platform provides a broadly applicable model system to potentially study diseases involving primarily embryonic craniofacial bone disorders, where direct diagnosis and adequate animal disease models are limited.
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Affiliation(s)
- Bumjin Namkoong
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Sinan Güven
- Demirci BAMM Labs, Canary Center at Stanford for Early Cancer Detection, Department of Radiology, Department of Electrical Engineering (By courtesy), Stanford School of Medicine, Palo Alto, CA 94304, USA; Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Balcova, 35350 Izmir, Turkey
| | - Shwathy Ramesan
- Demirci BAMM Labs, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Volha Liaudanskaya
- Demirci BAMM Labs, Canary Center at Stanford for Early Cancer Detection, Department of Radiology, Department of Electrical Engineering (By courtesy), Stanford School of Medicine, Palo Alto, CA 94304, USA
| | - Arhat Abzhanov
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA; Current address: Department of Life Sciences, Imperial College London, Silwood Park Campus Buckhurst Road, Ascot, Berkshire SL5 7PY, United Kingdom; Current address: Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom.
| | - Utkan Demirci
- Demirci BAMM Labs, Canary Center at Stanford for Early Cancer Detection, Department of Radiology, Department of Electrical Engineering (By courtesy), Stanford School of Medicine, Palo Alto, CA 94304, USA; Demirci BAMM Labs, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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29
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Sun Q, Gu Y, Zhang W, Dziopa L, Zilberberg J, Lee W. Ex vivo 3D osteocyte network construction with primary murine bone cells. Bone Res 2015; 3:15026. [PMID: 26421212 PMCID: PMC4576492 DOI: 10.1038/boneres.2015.26] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 07/14/2015] [Accepted: 08/11/2015] [Indexed: 01/23/2023] Open
Abstract
Osteocytes reside as three-dimensionally (3D) networked cells in the lacunocanalicular structure of bones and regulate bone and mineral homeostasis. Despite of their important regulatory roles, in vitro studies of osteocytes have been challenging because: (1) current cell lines do not sufficiently represent the phenotypic features of mature osteocytes and (2) primary cells rapidly differentiate to osteoblasts upon isolation. In this study, we used a 3D perfusion culture approach to: (1) construct the 3D cellular network of primary murine osteocytes by biomimetic assembly with microbeads and (2) reproduce ex vivo the phenotype of primary murine osteocytes, for the first time to our best knowledge. In order to enable 3D construction with a sufficient number of viable cells, we used a proliferated osteoblastic population of healthy cells outgrown from digested bone chips. The diameter of microbeads was controlled to: (1) distribute and entrap cells within the interstitial spaces between the microbeads and (2) maintain average cell-to-cell distance to be about 19 µm. The entrapped cells formed a 3D cellular network by extending and connecting their processes through openings between the microbeads. Also, with increasing culture time, the entrapped cells exhibited the characteristic gene expressions (SOST and FGF23) and nonproliferative behavior of mature osteocytes. In contrast, 2D-cultured cells continued their osteoblastic differentiation and proliferation. This 3D biomimetic approach is expected to provide a new means of: (1) studying flow-induced shear stress on the mechanotransduction function of primary osteocytes, (2) studying physiological functions of 3D-networked osteocytes with in vitro convenience, and (3) developing clinically relevant human bone disease models.
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Affiliation(s)
- Qiaoling Sun
- Department of Materials Science and Chemical Engineering, Stevens Institute of Technology , Hoboken, NJ, USA
| | - Yexin Gu
- Department of Materials Science and Chemical Engineering, Stevens Institute of Technology , Hoboken, NJ, USA
| | - Wenting Zhang
- Department of Materials Science and Chemical Engineering, Stevens Institute of Technology , Hoboken, NJ, USA
| | - Leah Dziopa
- John Theurer Cancer Center, Hackensack University Medical Center , Hackensack, NJ, USA
| | - Jenny Zilberberg
- John Theurer Cancer Center, Hackensack University Medical Center , Hackensack, NJ, USA
| | - Woo Lee
- Department of Materials Science and Chemical Engineering, Stevens Institute of Technology , Hoboken, NJ, USA
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30
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Biology of Bone Tissue: Structure, Function, and Factors That Influence Bone Cells. BIOMED RESEARCH INTERNATIONAL 2015; 2015:421746. [PMID: 26247020 PMCID: PMC4515490 DOI: 10.1155/2015/421746] [Citation(s) in RCA: 931] [Impact Index Per Article: 103.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 04/30/2015] [Accepted: 05/04/2015] [Indexed: 02/06/2023]
Abstract
Bone tissue is continuously remodeled through the concerted actions of bone cells, which include bone resorption by osteoclasts and bone formation by osteoblasts, whereas osteocytes act as mechanosensors and orchestrators of the bone remodeling process. This process is under the control of local (e.g., growth factors and cytokines) and systemic (e.g., calcitonin and estrogens) factors that all together contribute for bone homeostasis. An imbalance between bone resorption and formation can result in bone diseases including osteoporosis. Recently, it has been recognized that, during bone remodeling, there are an intricate communication among bone cells. For instance, the coupling from bone resorption to bone formation is achieved by interaction between osteoclasts and osteoblasts. Moreover, osteocytes produce factors that influence osteoblast and osteoclast activities, whereas osteocyte apoptosis is followed by osteoclastic bone resorption. The increasing knowledge about the structure and functions of bone cells contributed to a better understanding of bone biology. It has been suggested that there is a complex communication between bone cells and other organs, indicating the dynamic nature of bone tissue. In this review, we discuss the current data about the structure and functions of bone cells and the factors that influence bone remodeling.
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Prideaux M, Staines KA, Jones ER, Riley GP, Pitsillides AA, Farquharson C. MMP and TIMP temporal gene expression during osteocytogenesis. Gene Expr Patterns 2015; 18:29-36. [PMID: 25982959 DOI: 10.1016/j.gep.2015.04.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 04/20/2015] [Accepted: 04/27/2015] [Indexed: 01/01/2023]
Abstract
Osteocytes within bone differentiate from osteoblast precursors which reside in a mineralised extracellular matrix (ECM). Fully differentiated osteocytes are critical for bone development and function but the factors that regulate this differentiation process are unknown. The enzymes primarily responsible for ECM remodelling are matrix metalloproteinases (MMP); however, the expression and role of MMPs during osteocytogenesis is undefined. Here we used MLO-A5 cells to determine the temporal gene expressions of the MMP family and their endogenous inhibitors--tissue inhibitors of metalloproteinases (TIMPs) during osteocytogenesis. RT-qPCR revealed expression of 14 Mmps and 3 Timps in MLO-A5 cells. Mmp2, Mmp23 and Mmp28 were decreased concurrent with mineralisation onset (P < 0.05*). Mmp14 and Mmp19 mRNAs were also significantly increased at day 3 (P < 0.05*) before returning to baseline levels at day 6. Decreased expressions of Timp1, Timp2 and Timp3 mRNA were observed by day 6 compared to day 0 (P < 0.05*). To examine whether these changes are linked to osteocytogenesis, we determined Mmp/Timp mRNA expressions in mineralisation-limited conditions. RT-qPCR revealed that the previously observed decreases in Mmp2, Mmp23 and Mmp28 were not observed in these mineralisation-limited cultures, therefore closely linking these MMPs with osteocyte differentiation. Similarly, we found differential expression of Timp1, Timp2 and Timp3 mRNA in mineralisation-restricted cultures (P < 0.05*). In conclusion, we have identified several members of the MMP/TIMP families as regulators of ECM remodelling necessary for the acquisition of the osteocyte phenotype.
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Affiliation(s)
- M Prideaux
- The University of Adelaide, North Terrace, Adelaide, SA 5005, Australia
| | - K A Staines
- Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG.
| | - E R Jones
- University of East Anglia, Norwich NR4 7TJ, UK
| | - G P Riley
- University of East Anglia, Norwich NR4 7TJ, UK
| | - A A Pitsillides
- Royal Veterinary College, Royal College Street, London NW1 0TU, UK
| | - C Farquharson
- Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG
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Yamazaki M, Kawai M, Miyagawa K, Ohata Y, Tachikawa K, Kinoshita S, Nishino J, Ozono K, Michigami T. Interleukin-1-induced acute bone resorption facilitates the secretion of fibroblast growth factor 23 into the circulation. J Bone Miner Metab 2015; 33:342-54. [PMID: 24996526 DOI: 10.1007/s00774-014-0598-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 05/01/2014] [Indexed: 12/12/2022]
Abstract
Fibroblast growth factor 23 (FGF23), a central regulator of phosphate and vitamin D metabolism, is mainly produced by osteocytes in bone and exerts its effects on distant organs. Despite its endocrine function, the mechanism controlling serum FGF23 levels is not fully understood. Here we tested the hypothesis that osteoclastic bone resorption may play a role in regulating circulating levels of FGF23, using a mouse model where injections of interleukin (IL)-1β into the subcutaneous tissue over the calvaria induced rapid bone resorption. A significant amount of FGF23 was detected in the extracts from mouse bones, which supports the idea that FGF23 stays in bone for a while after its production. IL-1β-induced bone resorption was associated with elevated serum FGF23 levels, an effect abolished by pre-treatment with pamidronate. Fgf23 expression was not increased in either the calvariae or tibiae of IL-1β-injected mice, which suggests that IL-1β facilitated the entry of FGF23 protein into circulation by accelerating bone resorption rather than increasing its gene expression. The direct effect of IL-1β on bone was confirmed when it increased FGF23 levels in the conditioned media of mouse calvariae in organ culture. Repeated treatment of the cultured calvariae with IL-1β led to a refractory phase, where FGF23 was not mobilized by IL-1β anymore. Consistent with the in vivo results, treatment with IL-1β failed to increase Fgf23 mRNA in isolated primary osteocytes and osteoblasts. These results suggest that FGF23 produced by osteocytes remains in bone, and that rapid bone resorption facilitates its entry into the bloodstream.
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Affiliation(s)
- Miwa Yamazaki
- Department of Bone and Mineral Research, Osaka Medical Center and Research Institute for Maternal and Child Health, Izumi, Osaka, 594-1101, Japan
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de Rooij KE, van der Velde M, de Wilt E, Deckers MML, Bezemer M, Waarsing JH, Que I, Chan AB, Kaijzel EL, Löwik CWGM. Identification of receptor-type protein tyrosine phosphatase μ as a new marker for osteocytes. Histochem Cell Biol 2015; 144:1-11. [PMID: 25850409 PMCID: PMC4468792 DOI: 10.1007/s00418-015-1319-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2015] [Indexed: 12/17/2022]
Abstract
Osteocytes are the predominant cells in bone, where they form a cellular network and display important functions in bone homeostasis, phosphate metabolism and mechanical transduction. Several proteins strongly expressed by osteocytes are involved in these processes, e.g., sclerostin, DMP-1, PHEX, FGF23 and MEPE, while others are upregulated during differentiation of osteoblasts into osteocytes, e.g., osteocalcin and E11. The receptor-type protein tyrosine phosphatase µ (RPTPμ) has been described to be expressed in cells which display a cellular network, e.g., endothelial and neuronal cells, and is implied in mechanotransduction. In a capillary outgrowth assay using metatarsals derived from RPTPμ-knock-out/LacZ knock-in mice, we observed that the capillary structures grown out of the metatarsals were stained blue, as expected. Surprisingly, cells within the metatarsal bone tissue were positive for LacZ activity as well, indicating that RPTPμ is also expressed by osteocytes. Subsequent histochemical analysis showed that within bone, RPTPμ is expressed exclusively in early-stage osteocytes. Analysis of bone marrow cell cultures revealed that osteocytes are present in the nodules and an enzymatic assay enabled the quantification of the amount of osteocytes. No apparent bone phenotype was observed when tibiae of RPTPμ-knock-out/LacZ knock-in mice were analyzed by μCT at several time points during aging, although a significant reduction in cortical bone was observed in RPTPμ-knock-out/LacZ knock-in mice at 20 weeks. Changes in trabecular bone were more subtle. Our data show that RPTPμ is a new marker for osteocytes.
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Affiliation(s)
- Karien E de Rooij
- Experimental Molecular Imaging, Department of Radiology, Leiden University Medical Center, Albinusdreef 2, PO Box 9600, 2300 RC, Leiden, The Netherlands,
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Rensberger JM, Martínez RN. Bone cells in birds show exceptional surface area, a characteristic tracing back to saurischian dinosaurs of the late Triassic. PLoS One 2015; 10:e0119083. [PMID: 25830561 PMCID: PMC4382344 DOI: 10.1371/journal.pone.0119083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 01/27/2015] [Indexed: 11/23/2022] Open
Abstract
Background Dinosaurs are unique among terrestrial tetrapods in their body sizes, which range from less than 3 gm in hummingbirds to 70,000 kg or more in sauropods. Studies of the microstructure of bone tissue have indicated that large dinosaurs, once believed to be slow growing, attained maturity at rates comparable to or greater than those of large mammals. A number of structural criteria in bone tissue have been used to assess differences in rates of osteogenesis in extinct taxa, including counts of lines of arrested growth and the density of vascular canals. Methodology/Principal Findings Here, we examine the density of the cytoplasmic surface of bone-producing cells, a feature which may set an upper limit to the rate of osteogenesis. Osteocyte lacunae and canaliculi, the cavities in bone containing osteocytes and their extensions, were measured in thin-sections of primary (woven and parallel fibered) bone in a diversity of tetrapods. The results indicate that bone cell surfaces are more densely organized in the Saurischia (extant birds, extinct Mesozoic Theropoda and Sauropodomorpha) than in other tetrapods, a result of denser branching of the cell extensions. The highest postnatal growth rates among extant tetrapods occur in modern birds, the only surviving saurischians, and the finding of exceptional cytoplasmic surface area of the cells that produce bone in this group suggests a relationship with bone growth rate. In support of this relationship is finding the lowest cell surface density among the saurischians examined in Dinornis, a member of a group of ratites that evolved in New Zealand in isolation from mammalian predators and show other evidence of lowered maturation rates.
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Affiliation(s)
- John M. Rensberger
- Department of Earth and Space Sciences, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| | - Ricardo N. Martínez
- Museo de Ciencias Naturales, Universidad Nacional de San Juan, San Juan, Argentina
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Chia LY, Walsh NC, Martin TJ, Sims NA. Isolation and gene expression of haematopoietic-cell-free preparations of highly purified murine osteocytes. Bone 2015; 72:34-42. [PMID: 25460578 DOI: 10.1016/j.bone.2014.11.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 10/14/2014] [Accepted: 11/11/2014] [Indexed: 10/24/2022]
Abstract
To define their gene expression and function, osteocytes are commonly isolated and purified by fluorescence-activated cell sorting (FACS) from mice expressing GFP directed by the dentin matrix protein 1 (Dmp1) promoter (DMP1-GFP). These cells express mRNA for osteocyte genes, including sclerostin (Sost) and Dmp1, and genes associated with the osteoclast phenotype: Dcstamp, Oscar, Cathepsin K (Ctsk), tartrate resistant acid phosphatase (TRAP/Acp5) and calcitonin receptor (Calcr). This suggests either that osteoclasts and osteocytes share genes and functions or that DMP1-GFP(+) preparations contain haematopoietic osteoclasts. To resolve this we stained DMP1-GFP cells for haematopoietic lineage (Lin) surface markers (CD2, CD3e, CD4, CD45, CD5, CD8, CD11b, B220, Gr1, Ter119) and CD31. Lin(-)CD31(-) (Lin(-)) and Lin(+)CD31(+) (Lin(+)) populations were analysed for GFP, and the four resulting populations assessed by quantitative real-time PCR. Lin(-)GFP(+) cells expressed mRNAs for Sost, Dmp1, and Mepe, confirming their osteocyte identity. Dcstamp and Oscar mRNAs were restricted to haematopoietic (Lin(+)) cells, but Calcr, Ctsk and Acp5 were readily detected in purified osteocytes (Lin(-)GFP(+)). The capacity of these purified osteocytes to support osteoclastogenesis was assessed: no TRAP+ cells with >2 nuclei were formed when purified osteocytes were cultured with bone marrow macrophages and stimulated with 1,25-dihydroxyvitamin-D3/prostaglandin E2. Lin(-)GFP(+) osteocytes also expressed lower levels of Tnfsf11 (RANKL) mRNA than the osteoblast-enriched population (Lin(-)GFP(-)). This demonstrates the importance of haematopoietic depletion in generating highly purified osteocytes and shows that osteocytes express Acp5, Ctsk and Calcr, but not other osteoclast markers, and do not fully support osteoclast formation in vitro.
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Affiliation(s)
- Ling Yeong Chia
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia; Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, Victoria, Australia
| | - Nicole C Walsh
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia; Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, Victoria, Australia
| | - T John Martin
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia; Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, Victoria, Australia
| | - Natalie A Sims
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia; Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, Victoria, Australia.
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Abstract
Osteocytes are thought to be the mechanosensors of bone by sensing mechanical loads imposed upon the bone and transmitting these signals to the other bone cells to initiate bone modeling and remodeling. The location of osteocytes deep within bone is ideal for their function. However, this location makes the study of osteocytes in vivo technically difficult. There are several methods for obtaining and culturing primary osteocytes for in vitro experiments and ex vivo observation. In this chapter, several proven methods are discussed including the isolation of avian osteocytes from chicks and osteocytes from calvaria and long bones of young mice. A detailed protocol for the isolation of osteocytes from hypermineralized bone of mature and aged animals is provided.
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Affiliation(s)
- Amber Rath Stern
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, 650 E 25th Street, Room 3144, Kansas City, MO, 64105, USA
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Castania VA, Silveira JWDSD, Issy AC, Pitol DL, Castania ML, Neto AD, Bel EAD, Defino HLA. Advantages of a combined method of decalcification compared to EDTA. Microsc Res Tech 2014; 78:111-8. [PMID: 25452153 DOI: 10.1002/jemt.22451] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 10/23/2014] [Indexed: 11/10/2022]
Abstract
Decalcification of mineralized tissues is an essential step during tissue processing in the routine histopathology. The time required for complete decalcification, and the effect of decalcifier on cellular and tissue morphology are important parameters which influence the selection of decalcifying agents. In this study, we compared a decalcifying solution (ETDA) composed of both acid and chelating agents to a classical and well-known decalcifying agent (EDTA). To this purpose, the optic density of bone radiographs, residual calcium analysis, bone sample weight, and histological and immunohistochemical analysis were performed. Our data suggest that, similarly to EDTA, the ETDA solution completely removes the calcium ions from the samples enabling easy sectioning. However, unlike the EDTA, this agent takes much less time. Furthermore, both agents showed comparable decalcification efficacy, and similarly, they did not produce cellular, tissue or antigenicity impairments. Therefore, ETDA may be a suitable option when it is necessary an association between a rapid and complete removal of calcium minerals, and a suitable preservation of structure and antigenicity of tissues.
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Affiliation(s)
- Vitor Aparecido Castania
- Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, School of Medicine of Ribeirão Preto, University of Sao Paulo, Ribeirao Preto/SP, Brazil
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Genetos DC, Wong A, Weber TJ, Karin NJ, Yellowley CE. Impaired osteoblast differentiation in annexin A2- and -A5-deficient cells. PLoS One 2014; 9:e107482. [PMID: 25222280 PMCID: PMC4164658 DOI: 10.1371/journal.pone.0107482] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/18/2014] [Indexed: 11/18/2022] Open
Abstract
Annexins are a class of calcium-binding proteins with diverse functions in the regulation of lipid rafts, inflammation, fibrinolysis, transcriptional programming and ion transport. Within bone, they are well-characterized as components of mineralizing matrix vesicles, although little else is known as to their function during osteogenesis. We employed shRNA to generate annexin A2 (AnxA2)- or annexin A5 (AnxA5)-knockdown pre-osteoblasts, and determined whether proliferation or osteogenic differentiation was altered in knockdown cells, compared to pSiren (Si) controls. We report that DNA content, a marker of proliferation, was significantly reduced in both AnxA2 and AnxA5 knockdown cells. Alkaline phosphatase expression and activity were also suppressed in AnxA2- or AnxA5-knockdown after 14 days of culture. The pattern of osteogenic gene expression was altered in knockdown cells, with Col1a1 expressed more rapidly in knock-down cells, compared to pSiren. In contrast, Runx2, Ibsp, and Bglap all revealed decreased expression after 14 days of culture. In both AnxA2- and AnxA5-knockdown, interleukin-induced STAT6 signaling was markedly attenuated compared to pSiren controls. These data suggest that AnxA2 and AnxA5 can influence bone formation via regulation of osteoprogenitor proliferation, differentiation, and responsiveness to cytokines in addition to their well-studied function in matrix vesicles.
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Affiliation(s)
- Damian C. Genetos
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America
| | - Alice Wong
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America
| | - Thomas J. Weber
- Systems Toxicology, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Norman J. Karin
- Systems Toxicology, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Clare E. Yellowley
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America
- * E-mail:
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Balaji Raghavendran HR, Puvaneswary S, Talebian S, Raman Murali M, Vasudevaraj Naveen S, Krishnamurithy G, McKean R, Kamarul T. A comparative study on in vitro osteogenic priming potential of electron spun scaffold PLLA/HA/Col, PLLA/HA, and PLLA/Col for tissue engineering application. PLoS One 2014; 9:e104389. [PMID: 25140798 PMCID: PMC4139278 DOI: 10.1371/journal.pone.0104389] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Accepted: 07/08/2014] [Indexed: 11/19/2022] Open
Abstract
A comparative study on the in vitro osteogenic potential of electrospun poly-L-lactide/hydroxyapatite/collagen (PLLA/HA/Col, PLLA/HA, and PLLA/Col) scaffolds was conducted. The morphology, chemical composition, and surface roughness of the fibrous scaffolds were examined. Furthermore, cell attachment, distribution, morphology, mineralization, extracellular matrix protein localization, and gene expression of human mesenchymal stromal cells (hMSCs) differentiated on the fibrous scaffolds PLLA/Col/HA, PLLA/Col, and PLLA/HA were also analyzed. The electrospun scaffolds with a diameter of 200–950 nm demonstrated well-formed interconnected fibrous network structure, which supported the growth of hMSCs. When compared with PLLA/H%A and PLLA/Col scaffolds, PLLA/Col/HA scaffolds presented a higher density of viable cells and significant upregulation of genes associated with osteogenic lineage, which were achieved without the use of specific medium or growth factors. These results were supported by the elevated levels of calcium, osteocalcin, and mineralization (P<0.05) observed at different time points (0, 7, 14, and 21 days). Furthermore, electron microscopic observations and fibronectin localization revealed that PLLA/Col/HA scaffolds exhibited superior osteoinductivity, when compared with PLLA/Col or PLLA/HA scaffolds. These findings indicated that the fibrous structure and synergistic action of Col and nano-HA with high-molecular-weight PLLA played a vital role in inducing osteogenic differentiation of hMSCs. The data obtained in this study demonstrated that the developed fibrous PLLA/Col/HA biocomposite scaffold may be supportive for stem cell based therapies for bone repair, when compared with the other two scaffolds.
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Affiliation(s)
- Hanumantha Rao Balaji Raghavendran
- Tissue Engineering Group (TEG), National Orthopaedic Centre of Excellence in Research and Learning (NOCERAL), Department of Orthopaedic Surgery, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- * E-mail: (HBR); (TK)
| | - Subramaniam Puvaneswary
- Tissue Engineering Group (TEG), National Orthopaedic Centre of Excellence in Research and Learning (NOCERAL), Department of Orthopaedic Surgery, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Sepehr Talebian
- Department of Mechanical Engineering, Engineering Faculty, University of Malaya, Kuala Lumpur, Malaysia
| | - Malliga Raman Murali
- Tissue Engineering Group (TEG), National Orthopaedic Centre of Excellence in Research and Learning (NOCERAL), Department of Orthopaedic Surgery, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Sangeetha Vasudevaraj Naveen
- Tissue Engineering Group (TEG), National Orthopaedic Centre of Excellence in Research and Learning (NOCERAL), Department of Orthopaedic Surgery, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - G. Krishnamurithy
- Tissue Engineering Group (TEG), National Orthopaedic Centre of Excellence in Research and Learning (NOCERAL), Department of Orthopaedic Surgery, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Robert McKean
- The Electrospinning Company Ltd, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire, United Kingdom
| | - Tunku Kamarul
- Tissue Engineering Group (TEG), National Orthopaedic Centre of Excellence in Research and Learning (NOCERAL), Department of Orthopaedic Surgery, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- Clinical Investigative Centre, Faculty of Medicine, University Malaya Medical Center, Kuala Lumpur, Malaysia
- * E-mail: (HBR); (TK)
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Ayala-Peña V, Santillán G, Scolaro L. Experimental in vitro infection of rat osteoblasts with measles virus stimulates osteogenic differentiation. Biochem Biophys Res Commun 2014; 451:609-14. [PMID: 25128831 DOI: 10.1016/j.bbrc.2014.08.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 08/06/2014] [Indexed: 10/24/2022]
Abstract
In this work we characterized the infection of a primary culture of rat osteoblastic lineage cells (OBCs) with measles virus (MeV) and the effect of infection on cell differentiation and maturation. Infection of OBCs with MeV led to high titers of infectivity released early after infection. Also, analysis of mRNAs corresponding to osteogenic differentiation markers like alkaline phosphatase (ALP), bone sialo-protein (BSP) and bone morphogenetic proteins (BMPs) 1-4-5-7 in OBCs revealed higher values (2-75-fold of increment) for infected cells in comparison with uninfected controls. Differentiation of OBCs in osteogenic medium prior to infection influenced the level of stimulation induced by MeV. Furthermore, treatment of OBCs with Ly294002, a PI3K/AKT inhibitor, increased viral titers, whereas treatment with 10μM or 100μM ATPγS diminished MeV multiplication. In addition, increments of osteogenic differentiation markers induced by MeV infection were not modified either by treatment with Ly294002 or ATPγS. These data provide the first evidence demonstrating that MeV can infect osteoblasts in vitro leading to osteoblastic differentiation, a key feature in bone pathogenic processes like otosclerosis.
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Affiliation(s)
- V Ayala-Peña
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, (B8000ICN) Bahía Blanca, Argentina
| | - G Santillán
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, (B8000ICN) Bahía Blanca, Argentina
| | - L Scolaro
- Laboratorio de Virología, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, Piso 4, Buenos Aires 1428, Argentina.
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Prideaux M, Wijenayaka AR, Kumarasinghe DD, Ormsby RT, Evdokiou A, Findlay DM, Atkins GJ. SaOS2 Osteosarcoma cells as an in vitro model for studying the transition of human osteoblasts to osteocytes. Calcif Tissue Int 2014; 95:183-93. [PMID: 24916279 DOI: 10.1007/s00223-014-9879-y] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 05/21/2014] [Indexed: 12/18/2022]
Abstract
The central importance of osteocytes in regulating bone homeostasis is becoming increasingly apparent. However, the study of these cells has been restricted by the relative paucity of cell line models, especially those of human origin. Therefore, we investigated the extent to which SaOS2 human osteosarcoma cells can differentiate into osteocyte-like cells. During culture under the appropriate mineralising conditions, SaOS2 cells reproducibly synthesised a bone-like mineralised matrix and temporally expressed the mature osteocyte marker genes SOST, DMP1, PHEX and MEPE and down-regulated expression of RUNX2 and COL1A1. SaOS2 cells cultured in 3D collagen gels acquired a dendritic morphology, characteristic of osteocytes, with multiple interconnecting cell processes. These findings suggest that SaOS2 cells have the capacity to differentiate into mature osteocyte-like cells under mineralising conditions. PTH treatment of SaOS2 cells resulted in strong down-regulation of SOST mRNA expression at all time points tested. Interestingly, PTH treatment resulted in the up-regulation of RANKL mRNA expression only at earlier stages of differentiation. These findings suggest that the response to PTH is dependent on the differentiation stage of the osteoblast/osteocyte. Together, our results demonstrate that SaOS2 cells can be used as a human model to investigate responses to osteotropic stimuli throughout differentiation to a mature osteocyte-like stage.
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Affiliation(s)
- Matthew Prideaux
- Bone Cell Biology Group, Centre for Orthopaedic and Trauma Research, The University of Adelaide, North Terrace, Adelaide, SA, 5005, Australia
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Dysregulated gene expression in the primary osteoblasts and osteocytes isolated from hypophosphatemic Hyp mice. PLoS One 2014; 9:e93840. [PMID: 24710520 PMCID: PMC3977859 DOI: 10.1371/journal.pone.0093840] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 03/07/2014] [Indexed: 12/27/2022] Open
Abstract
Osteocytes express multiple genes involved in mineral metabolism including PHEX, FGF23, DMP1 and FAM20C. In Hyp mice, a murine model for X-linked hypophosphatemia (XLH), Phex deficiency results in the overproduction of FGF23 in osteocytes, which leads to hypophosphatemia and impaired vitamin D metabolism. In this study, to further clarify the abnormality in osteocytes of Hyp mice, we obtained detailed gene expression profiles in osteoblasts and osteocytes isolated from the long bones of 20-week-old Hyp mice and wild-type (WT) control mice. The expression of Fgf23, Dmp1, and Fam20c was higher in osteocytic cells than in osteoblastic cells in both genotypes, and was up-regulated in Hyp cells. Interestingly, the up-regulation of these genes in Hyp bones began before birth. On the other hand, the expression of Slc20a1 encoding the sodium/phosphate (Na+/Pi) co-transporter Pit1 was increased in osteoblasts and osteocytes from adult Hyp mice, but not in Hyp fetal bones. The direct effects of extracellular Pi and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] on isolated osteoblastic and osteocytic cells were also investigated. Twenty-four-hour treatment with 10−8 M 1,25(OH)2D3 increased the expression of Fgf23 in WT osteoblastic cells but not in osteocytic cells. Dmp1 expression in osteocytic cells was increased due to the 24-hour treatment with 10 mM Pi and was suppressed by 10−8 M 1,25(OH)2D3 in WT osteocytic cells. We also found the up-regulation of the genes for FGF1, FGF2, their receptors, and Egr-1 which is a target of FGF signaling, in Hyp osteocytic cells, suggesting the activation of FGF/FGFR signaling. These results implicate the complex gene dysregulation in osteoblasts and osteocytes of Hyp mice, which might contribute to the pathogenesis.
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Yang J, Liu A, Han Y, Li Q, Tian J, Zhou C. Osteodifferentiation of mesenchymal stem cells on chitosan/hydroxyapatite composite films. J Biomed Mater Res A 2013; 102:1202-9. [DOI: 10.1002/jbm.a.34756] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 03/20/2013] [Accepted: 04/04/2013] [Indexed: 01/03/2023]
Affiliation(s)
- Julin Yang
- Department of Health Service and Management, Ningbo College of Health Sciences; Ningbo 315100 China
| | - Aiming Liu
- Department of Pharmacology, Medical School of Ningbo University; Ningbo 315211 China
| | - Yuanyuan Han
- Department of Materials Science and Engineering, Jinan University; Guangzhou 510632 China
| | - Qingning Li
- Department of Pharmacology, Medical School of Ningbo University; Ningbo 315211 China
| | - Jinhuan Tian
- Department of Materials Science and Engineering, Jinan University; Guangzhou 510632 China
| | - Changren Zhou
- Department of Materials Science and Engineering, Jinan University; Guangzhou 510632 China
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Mullen CA, Haugh MG, Schaffler MB, Majeska RJ, McNamara LM. Osteocyte differentiation is regulated by extracellular matrix stiffness and intercellular separation. J Mech Behav Biomed Mater 2013; 28:183-94. [PMID: 23994943 DOI: 10.1016/j.jmbbm.2013.06.013] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 06/14/2013] [Accepted: 06/28/2013] [Indexed: 01/04/2023]
Abstract
Osteocytes are terminally differentiated bone cells, derived from osteoblasts, which are vital for the regulation of bone formation and resorption. ECM stiffness and cell seeding density have been shown to regulate osteoblast differentiation, but the precise cues that initiate osteoblast-osteocyte differentiation are not yet understood. In this study, we cultured MC3T3-E1 cells on (A) substrates of different chemical compositions and stiffnesses, as well as, (B) substrates of identical chemical composition but different stiffnesses. The effect of cell separation was investigated by seeding cells at different densities on each substrate. Cells were evaluated for morphology, alkaline phosphatase (ALP), matrix mineralisation, osteoblast specific genes (Type 1 collagen, Osteoblast specific factor (OSF-2)), and osteocyte specific proteins (dentin matrix protein 1 (DMP-1), sclerostin (Sost)). We found that osteocyte differentiation (confirmed by dendritic morphology, mineralisation, reduced ALP, Col type 1 and OSF-2 and increased DMP-1 and Sost expression) was significantly increased on soft collagen based substrates, at low seeding densities compared to cells on stiffer substrates or those plated at high seeding density. We propose that the physical nature of the ECM and the necessity for cells to establish a communication network contribute substantially to a concerted shift toward an osteocyte-like phenotype by osteoblasts in vitro.
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Affiliation(s)
- C A Mullen
- Centre for Biomechanics Research (BMEC), Mechanical and Biomedical Engineering, NUI Galway, Ireland; National Centre for Biomedical Engineering Science (NCBES), NUI Galway, Ireland
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Kalajzic I, Matthews BG, Torreggiani E, Harris MA, Divieti Pajevic P, Harris SE. In vitro and in vivo approaches to study osteocyte biology. Bone 2013; 54:296-306. [PMID: 23072918 PMCID: PMC3566324 DOI: 10.1016/j.bone.2012.09.040] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 09/27/2012] [Accepted: 09/27/2012] [Indexed: 11/26/2022]
Abstract
Osteocytes, the most abundant cell population of the bone lineage, have been a major focus in the bone research field in recent years. This population of cells that resides within mineralized matrix is now thought to be the mechanosensory cell in bone and plays major roles in the regulation of bone formation and resorption. Studies of osteocytes had been impaired by their location, resulting in numerous attempts to isolate primary osteocytes and to generate cell lines representative of the osteocytic phenotype. Progress has been achieved in recent years by utilizing in vivo genetic technology and generation of osteocyte directed transgenic and gene deficiency mouse models. We will provide an overview of the current in vitro and in vivo models utilized to study osteocyte biology. We discuss generation of osteocyte-like cell lines and isolation of primary osteocytes and summarize studies that have utilized these cellular models to understand the functional role of osteocytes. Approaches that attempt to selectively identify and isolate osteocytes using fluorescent protein reporters driven by regulatory elements of genes that are highly expressed in osteocytes will be discussed. In addition, recent in vivo studies utilizing overexpression or conditional deletion of various genes using dentin matrix protein (Dmp1) directed Cre recombinase are outlined. In conclusion, evaluation of the benefits and deficiencies of currently used cell lines/genetic models in understanding osteocyte biology underlines the current progress in this field. The future efforts will be directed towards developing novel in vitro and in vivo models that would additionally facilitate in understanding the multiple roles of osteocytes.
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Affiliation(s)
- Ivo Kalajzic
- Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, Connecticut 06032, USA.
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Nanofiber-based polyethersulfone scaffold and efficient differentiation of human induced pluripotent stem cells into osteoblastic lineage. Mol Biol Rep 2013; 40:4287-94. [PMID: 23657591 DOI: 10.1007/s11033-013-2515-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 04/27/2013] [Indexed: 01/08/2023]
Abstract
Human induced pluripotent stem cells (iPSCs) have been shown to have promising potential for regenerative medicine and tissue engineering applications. In the present study, osteogenic differentiation of human iPSCs was evaluated on polyethersulfone (PES) nanofibrous scaffold. According to the results, higher significant expressions of common osteogenic-related genes such as runx2, collagen type I, osteocalcin and osteonectin was observed in PES seeded human iPSCs compared with control. Alizarin red staining and alkaline phosphatase activity of differentiated iPSCs demonstrated significant osteoblastic differentiation potential of these cells. In this study biocompatibility of PES nanofibrous scaffold confirmed by flattened and spreading morphology of iPSCs under osteoblastic differentiation inductive culture. Taking together, nanofiber-based PES scaffold seeded iPSCs showed the highest capacity for differentiation into osteoblasts-like cells. These cells and PES scaffold were demonstrated to have great efficiency for treatment of bone damages and lesions.
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Yalak G, Vogel V. Extracellular phosphorylation and phosphorylated proteins: not just curiosities but physiologically important. Sci Signal 2012; 5:re7. [PMID: 23250399 DOI: 10.1126/scisignal.2003273] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mining of the literature and high-throughput mass spectrometry data from both healthy and diseased tissues and from body fluids reveals evidence that various extracellular proteins can exist in phosphorylated states. Extracellular kinases and phosphatases (ectokinases and ectophosphatases) are active in extracellular spaces during times of sufficiently high concentrations of adenosine triphosphate. There is evidence for a role of extracellular phosphorylation in various physiological functions, including blood coagulation, immune cell activation, and the formation of neuronal networks. Ectokinase activity is increased in some diseases, including cancer, Alzheimer's disease, and some microbial infections. We summarize the literature supporting the physiological and pathological roles of extracellularly localized protein kinases, protein phosphatases, and phosphorylated proteins and provide an analysis of the available mass spectrometry data to annotate potential extracellular phosphorylated proteins.
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Affiliation(s)
- Garif Yalak
- Department of Health Sciences and Technology, ETH Zurich, Wolfgang Pauli Strasse 10, HCI F443, CH-8093 Zurich, Switzerland
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Osteocytic osteolysis: time for a second look? BONEKEY REPORTS 2012; 1:229. [PMID: 24363929 PMCID: PMC3868715 DOI: 10.1038/bonekey.2012.229] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 10/18/2012] [Accepted: 10/29/2012] [Indexed: 11/08/2022]
Abstract
Over 100 years ago it was suggested that osteocytes could remodel their surrounding environment by removing and replacing bone. In the 1960s and 1970s, many observations were made to suggest that osteocytes could resorb bone and increase the size of their lacunae. This concept became known as osteocytic osteolysis and studies suggested that it occurred in response to diverse stimuli such as parathyroid hormone, calcium restriction, hibernation and reproductive cycles. However, this concept fell out of favor in the late 1970s when it became clear that osteoclasts were the principal bone-resorbing cells in the skeleton. Over the past decade, we have increasingly appreciated that osteocytes are remarkably versatile cells and are involved in all aspects of skeletal biology, including the response to loading, the regulation of bone turnover and the control of mineral metabolism. Recent data have demonstrated that osteocytes remodel their perilacunar and canalicular matrix and participate in the liberation of skeletal calcium stores during lactation. In light of these new findings, it may be time to reassess the concept of osteocytic osteolysis and reconsider whether osteocyte lacunar and canalicular remodeling contributes more broadly to the maintenance of skeletal and mineral homeostasis.
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Influence of BONITmatrix® and OSSA NOVA on the expression of bone specific genes. Ann Anat 2012; 194:524-8. [DOI: 10.1016/j.aanat.2012.02.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 02/08/2012] [Accepted: 02/20/2012] [Indexed: 11/17/2022]
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Prideaux M, Loveridge N, Pitsillides AA, Farquharson C. Extracellular matrix mineralization promotes E11/gp38 glycoprotein expression and drives osteocytic differentiation. PLoS One 2012; 7:e36786. [PMID: 22586496 PMCID: PMC3346717 DOI: 10.1371/journal.pone.0036786] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 04/13/2012] [Indexed: 11/19/2022] Open
Abstract
Osteocytes are terminally differentiated osteoblasts which reside in a mineralized extracellular matrix (ECM). The factors that regulate this differentiation process are unknown. We have investigated whether ECM mineralization could promote osteocyte formation. To do this we have utilised MLO-A5 pre-osteocyte-like cells and western blotting and comparative RT-PCR to examine whether the expression of osteocyte-selective markers is elevated concurrently with the onset of ECM mineralization. Secondly, if mineralization of the ECM is indeed a driver of osteocyte formation, we reasoned that impairment of ECM mineralization would result in a reversible inhibition of osteocyte formation. Supplementation of MLO-A5 cell cultures with ascorbic acid and phosphate promoted progressive ECM mineralization as well as temporally associated increases in expression of the osteocyte-selective markers, E11/gp38 glycoprotein and sclerostin. Consistent with a primary role for ECM mineralization in osteocyte formation, we also found that inhibition of ECM mineralization, by omitting phosphate or adding sodium pyrophosphate, a recognized inhibitor of hydroxyapatite formation, resulted in a 15-fold decrease in mineral deposition that was closely accompanied by lower expression of E11 and other osteocyte markers such as Dmp1, Cd44 and Sost whilst expression of osteoblast markers Ocn and Col1a increased. To rule out the possibility that such restriction of ECM mineralization may produce an irreversible modification in osteoblast behaviour to limit E11 expression and osteocytogenesis, we also measured the capacity of MLO-A5 cells to re-enter the osteocyte differentiation programme. We found that the mineralisation process was re-initiated and closely allied to increased expression of E11 protein after re-administration of phosphate or omission of sodium pyrophosphate, indicating an ECM mineralization-induced restoration in osteocyte formation. These results emphasise the importance of cell-ECM interactions in regulating osteoblast behaviour and, more importantly, suggest that ECM mineralization exerts pivotal control during terminal osteoblast differentiation and acquisition of the osteocyte phenotype.
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Affiliation(s)
- Matthew Prideaux
- Division of Developmental Biology, The Roslin Institute, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
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