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Knowles HJ, Chanalaris A, Koutsikouni A, Cribbs AP, Grover LM, Hulley PA. Mature primary human osteocytes in mini organotypic cultures secrete FGF23 and PTH1-34-regulated sclerostin. Front Endocrinol (Lausanne) 2023; 14:1167734. [PMID: 37223031 PMCID: PMC10200954 DOI: 10.3389/fendo.2023.1167734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/03/2023] [Indexed: 05/25/2023] Open
Abstract
Introduction For decades, functional primary human osteocyte cultures have been crucially needed for understanding their role in bone anabolic processes and in endocrine phosphate regulation via the bone-kidney axis. Mature osteocyte proteins (sclerostin, DMP1, Phex and FGF23) play a key role in various systemic diseases and are targeted by successful bone anabolic drugs (anti-sclerostin antibody and teriparatide (PTH1-34)). However, cell lines available to study osteocytes produce very little sclerostin and low levels of mature osteocyte markers. We have developed a primary human 3D organotypic culture system that replicates the formation of mature osteocytes in bone. Methods Primary human osteoblasts were seeded in a fibrinogen / thrombin gel around 3D-printed hanging posts. Following contraction of the gel around the posts, cells were cultured in osteogenic media and conditioned media was collected for analysis of secreted markers of osteocyte formation. Results The organoids were viable for at least 6 months, allowing co-culture with different cell types and testing of bone anabolic drugs. Bulk RNAseq data displayed the developing marker trajectory of ossification and human primary osteocyte formation in vitro over an initial 8- week period. Vitamin D3 supplementation increased mineralization and sclerostin secretion, while hypoxia and PTH1-34 modulated sclerostin. Our culture system also secreted FGF23, enabling the future development of a bone-kidney-parathyroid-vascular multi-organoid or organ-on-a-chip system to study disease processes and drug effects using purely human cells. Discussion This 3D organotypic culture system provides a stable, long-lived, and regulated population of mature human primary osteocytes for a variety of research applications.
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Affiliation(s)
- Helen J. Knowles
- Botnar Institute for Musculoskeletal Sciences, Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Anastasios Chanalaris
- Botnar Institute for Musculoskeletal Sciences, Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Argyro Koutsikouni
- School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Adam P. Cribbs
- Botnar Institute for Musculoskeletal Sciences, Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Translational Myeloma Research, Botnar Institute for Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Liam M. Grover
- Healthcare Technologies Institute, School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom
| | - Philippa A. Hulley
- Botnar Institute for Musculoskeletal Sciences, Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
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Kim J, Tomida K, Matsumoto T, Adachi T. Spheroid culture for chondrocytes triggers early stage of endochondral ossification. Biotechnol Bioeng 2022; 119:3311-3318. [PMID: 35923099 DOI: 10.1002/bit.28203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 07/07/2022] [Accepted: 07/30/2022] [Indexed: 11/11/2022]
Abstract
Endochondral ossification is the process of bone formation derived from growing cartilage during the development of the skeletal system. In previous studies, we have attempted to evoke the osteocyte differentiation of osteoblast precursor cells under a three-dimensional (3D) culture model. In order to recapitulate the endochondral ossification, the present study utilized the self-organized scaffold-free spheroid model reconstructed by pre-chondrocyte cells. Within 2-day cultivation in the absence of the chemically induced chondrogenesis supplements, the chondrocyte marker was greatly expressed in the inner region of the spheroid, whereas the hypertrophic chondrocyte marker was strongly detected in the surface region of the spheroid. Notably, we found out that the gene expression levels of osteocyte markers were also greatly up-regulated compared to the conventional 2D monolayer. Moreover, there was a hypertrophied morphologic change in the pre-chondrocyte spheroid from 4-day to 28-day cultivation. In this study, we highlighted the potentials of the 3D culture method to acquire the hypertrophic chondrocyte differentiation of the pre-chondrocyte cells to recapitulate the early stage of the endochondral ossification. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jeonghyun Kim
- Department of Mechanical Systems Engineering, Nagoya University, Nagoya, 464-8603, Japan
| | - Kosei Tomida
- Department of Mechanical Systems Engineering, Nagoya University, Nagoya, 464-8603, Japan
| | - Takeo Matsumoto
- Department of Mechanical Systems Engineering, Nagoya University, Nagoya, 464-8603, Japan
| | - Taiji Adachi
- Institute for Life and Medical Sciences, Kyoto University, Kyoto, 606-8507, Japan
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Kim J, Inagaki T, Sunaga J, Adachi T, Matsumoto T. Effect of chemically induced osteogenesis supplements on multicellular behavior of osteocytic spheroids. Biochem Biophys Res Commun 2022; 622:79-85. [PMID: 35870328 DOI: 10.1016/j.bbrc.2022.07.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 07/07/2022] [Indexed: 11/30/2022]
Abstract
Understanding in multicellular behaviors in three-dimensional (3D) culture models such as organoids is important to help us better comprehend the mechanisms of the morphogenesis and functions of diverse organs in vivo cellular environment. In this study, we elucidated the multicellular behaviors of the osteocytic spheroids in response to the chemically induced osteogenesis supplements (OS). Particularly, we conducted 1) size change measurement, 2) fusion experiment, and 3) collagen embedding experiment of spheroids, in response to the OS. We found out that the OS alters the multicellular behaviors of the spheroid by greater reduction in the size change measurement and slowing down the speed of fusion experiment and collagen embedding experiment of the spheroids. We also highlighted that the driving force of these changes was the tight actin filaments generated on the surface of the spheroids. Hence, the results altogether indicate that the spheroid model exerted the different multicellular behaviors against the differentiation capability. This study will contribute to understanding the multicellular behaviors of the 3D culture model reconstructed by the cells with greater cell-cell interaction force.
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Affiliation(s)
- Jeonghyun Kim
- Department of Mechanical Systems Engineering, Nagoya University, Nagoya, 464-8603, Japan.
| | - Takashi Inagaki
- Department of Mechanical Systems Engineering, Nagoya University, Nagoya, 464-8603, Japan
| | - Junko Sunaga
- Institute for Life and Medical Sciences, Kyoto University, Kyoto, 606-8507, Japan
| | - Taiji Adachi
- Institute for Life and Medical Sciences, Kyoto University, Kyoto, 606-8507, Japan
| | - Takeo Matsumoto
- Department of Mechanical Systems Engineering, Nagoya University, Nagoya, 464-8603, Japan
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Brady RT, O’Brien FJ, Hoey DA. The Impact of the Extracellular Matrix Environment on Sost Expression by the MLO-Y4 Osteocyte Cell Line. BIOENGINEERING (BASEL, SWITZERLAND) 2022; 9:bioengineering9010035. [PMID: 35049744 PMCID: PMC8772728 DOI: 10.3390/bioengineering9010035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 12/27/2022]
Abstract
Bone is a dynamic organ that can adapt its structure to meet the demands of its biochemical and biophysical environment. Osteocytes form a sensory network throughout the tissue and orchestrate tissue adaptation via the release of soluble factors such as a sclerostin. Osteocyte physiology has traditionally been challenging to investigate due to the uniquely mineralized extracellular matrix (ECM) of bone leading to the development of osteocyte cell lines. Importantly, the most widely researched and utilized osteocyte cell line: the MLO-Y4, is limited by its inability to express sclerostin (Sost gene) in typical in-vitro culture. We theorised that culture in an environment closer to the in vivo osteocyte environment could impact on Sost expression. Therefore, this study investigated the role of composition and dimensionality in directing Sost expression in MLO-Y4 cells using collagen-based ECM analogues. A significant outcome of this study is that MLO-Y4 cells, when cultured on a hydroxyapatite (HA)-containing two-dimensional (2D) film analogue, expressed Sost. Moreover, three-dimensional (3D) culture within HA-containing collagen scaffolds significantly enhanced Sost expression, demonstrating the impact of ECM composition and dimensionality on MLO-Y4 behaviour. Importantly, in this bone mimetic ECM environment, Sost expression was found to be comparable to physiological levels. Lastly, MLO-Y4 cells cultured in these novel conditions responded accordingly to fluid flow stimulation with a decrease in expression. This study therefore presents a novel culture system for the MLO-Y4 osteocyte cell line, ensuring the expression of an important osteocyte specific gene, Sost, overcoming a major limitation of this model.
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Affiliation(s)
- Robert T. Brady
- Tissue Engineering Research Group, Department of Anatomy & Regenerative Medicine, Royal College of Surgeons in Ireland, D02 YN77 Dublin, Ireland; (R.T.B.); (F.J.O.)
- Trinity Centre for Biomedical Engineering, School of Engineering, Trinity College Dublin, D02 PN40 Dublin, Ireland
- Advanced Materials and BioEngineering Research Centre (AMBER), Trinity College Dublin & Royal College of Surgeons in Ireland, D02 PN40 Dublin, Ireland
- Department of Mechanical, Manufacturing, and Biomedical Engineering, Trinity College Dublin, D02 PN40 Dublin, Ireland
| | - Fergal J. O’Brien
- Tissue Engineering Research Group, Department of Anatomy & Regenerative Medicine, Royal College of Surgeons in Ireland, D02 YN77 Dublin, Ireland; (R.T.B.); (F.J.O.)
- Trinity Centre for Biomedical Engineering, School of Engineering, Trinity College Dublin, D02 PN40 Dublin, Ireland
- Advanced Materials and BioEngineering Research Centre (AMBER), Trinity College Dublin & Royal College of Surgeons in Ireland, D02 PN40 Dublin, Ireland
| | - David A. Hoey
- Trinity Centre for Biomedical Engineering, School of Engineering, Trinity College Dublin, D02 PN40 Dublin, Ireland
- Advanced Materials and BioEngineering Research Centre (AMBER), Trinity College Dublin & Royal College of Surgeons in Ireland, D02 PN40 Dublin, Ireland
- Department of Mechanical, Manufacturing, and Biomedical Engineering, Trinity College Dublin, D02 PN40 Dublin, Ireland
- Correspondence:
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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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Cell-fate decision of mesenchymal stem cells toward osteocyte differentiation is committed by spheroid culture. Sci Rep 2021; 11:13204. [PMID: 34168224 PMCID: PMC8225633 DOI: 10.1038/s41598-021-92607-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/14/2021] [Indexed: 01/14/2023] Open
Abstract
Osteocytes are mechanosensory commander cells to regulate bone remodeling throughout the lifespan. While the osteocytes are known as terminally differentiated cells derived from mesenchymal stem cells, the detailed mechanisms of osteocyte differentiation remain unclear. In this study, we fabricated 3D self-organized spheroids using human mesenchymal stem cells (MSCs). Under the osteogenesis induction medium, the spheroid culture model exerted the osteocyte-likeness within 2 days compared to a conventional 2D monolayer model. Moreover, we showed that an inhibition of actin polymerization in the spheroid further up-regulated the osteocyte gene expressions. Notably, we represented that the cell condensed condition acquired in the 3D spheroid culture model determined a differentiation fate of MSCs to osteocytes. Taken together, we suggest that our self-organized spheroid model can be utilized as a new in vitro model to represent the osteocyte and to recapitulate an in vitro ossification process.
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Uniaxially fixed mechanical boundary condition elicits cellular alignment in collagen matrix with induction of osteogenesis. Sci Rep 2021; 11:9009. [PMID: 33907271 PMCID: PMC8079399 DOI: 10.1038/s41598-021-88505-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 04/13/2021] [Indexed: 02/08/2023] Open
Abstract
Osteocytes differentiated from osteoblasts play significant roles as mechanosensors in modulating the bone remodeling process. While the well-aligned osteocyte network along the trabeculae with slender cell processes perpendicular to the trabeculae surface is known to facilitate the sensing of mechanical stimuli by cells and the intracellular communication in the bone matrix, the mechanisms underlying osteocyte network formation remains unclear. Here, we developed a novel in vitro collagen matrix system exerting a uniaxially-fixed mechanical boundary condition on which mouse osteoblast-like MC3T3-E1 cells were subcultured, evoking cellular alignment along the uniaxial boundary condition. Using a myosin II inhibitor, blebbistatin, we showed that the intracellular tension via contraction of actin fibers contributed to the cellular alignment under the influence of isometric matrix condition along the uniaxially-fixed mechanical boundary condition. Furthermore, the cells actively migrated inside the collagen matrix and promoted the expression of osteoblast and osteocyte genes with their orientations aligned along the uniaxially-fixed boundary condition. Collectively, our results suggest that the intracellular tension of osteoblasts under a uniaxially-fixed mechanical boundary condition is one of the factors that determines the osteocyte alignment inside the bone matrix.
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