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Wang H, Li T, Jiang Y, Chen S, Wu Z, Zeng X, Yang K, Duan P, Zou S. Long non-coding RNA LncTUG1 regulates favourable compression force-induced cementocytes mineralization via PU.1/TLR4/SphK1 signalling. Cell Prolif 2024; 57:e13604. [PMID: 38318762 DOI: 10.1111/cpr.13604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 12/18/2023] [Accepted: 01/09/2024] [Indexed: 02/07/2024] Open
Abstract
Orthodontic tooth movement (OTM) is a highly coordinated biomechanical response to orthodontic forces with active remodelling of alveolar bone but minor root resorption. Such antiresorptive properties of root relate to cementocyte mineralization, the mechanisms of which remain largely unknown. This study used the microarray analysis to explore long non-coding ribonucleic acids involved in stress-induced cementocyte mineralization. Gain- and loss-of-function experiments, including Alkaline phosphatase (ALP) activity and Alizarin Red S staining, quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, and immunofluorescence analyses of mineralization-associated factors, were conducted to verify long non-coding ribonucleic acids taurine-upregulated gene 1 (LncTUG1) regulation in stress-induced cementocyte mineralization, via targeting the Toll-like receptor 4 (TLR4)/SphK1 axis. The luciferase reporter assays, chromatin immunoprecipitation assays, RNA pull-down, RNA immunoprecipitation, and co-localization assays were performed to elucidate the interactions between LncTUG1, PU.1, and TLR4. Our findings indicated that LncTUG1 overexpression attenuated stress-induced cementocyte mineralization, while blocking the TLR4/SphK1 axis reversed the inhibitory effect of LncTUG1 on stress-induced cementocyte mineralization. The in vivo findings also confirmed the involvement of TLR4/SphK1 signalling in cementocyte mineralization during OTM. Mechanistically, LncTUG1 bound with PU.1 subsequently enhanced TLR4 promotor activity and thus transcriptionally elevated the expression of TLR4. In conclusion, our data revealed a critical role of LncTUG1 in regulating stress-induced cementocyte mineralization via PU.1/TLR4/SphK1 signalling, which might provide further insights for developing novel therapeutic strategies that could protect roots from resorption during OTM.
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Affiliation(s)
- Han Wang
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Tiancheng Li
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Yukun Jiang
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Shuo Chen
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Zuping Wu
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou, China
| | - Xinyi Zeng
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Kuan Yang
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Peipei Duan
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Shujuan Zou
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Smit A, Meijer O, Winter E. The multi-faceted nature of age-associated osteoporosis. Bone Rep 2024; 20:101750. [PMID: 38566930 PMCID: PMC10985042 DOI: 10.1016/j.bonr.2024.101750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 03/03/2024] [Accepted: 03/04/2024] [Indexed: 04/04/2024] Open
Abstract
Age-associated osteoporosis (AAOP) poses a significant health burden, characterized by increased fracture risk due to declining bone mass and strength. Effective prevention and early treatment strategies are crucial to mitigate the disease burden and the associated healthcare costs. Current therapeutic approaches effectively target the individual contributing factors to AAOP. Nonetheless, the management of AAOP is complicated by the multitude of variables that affect its development. Main intrinsic and extrinsic factors contributing to AAOP risk are reviewed here, including mechanical unloading, nutrient deficiency, hormonal disbalance, disrupted metabolism, cognitive decline, inflammation and circadian disruption. Furthermore, it is discussed how these can be targeted for prevention and treatment. Although valuable as individual targets for intervention, the interconnectedness of these risk factors result in a unique etiology for every patient. Acknowledgement of the multifaceted nature of AAOP will enable the development of more effective and sustainable management strategies, based on a holistic, patient-centered approach.
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Affiliation(s)
- A.E. Smit
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden, the Netherlands
| | - O.C. Meijer
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden, the Netherlands
| | - E.M. Winter
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, the Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden, the Netherlands
- Department of Medicine, Center for Bone Quality, Leiden University Medical Center, Leiden, the Netherlands
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3
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Sarazin BA, Liu B, Goldman E, Whitefield AN, Lynch ME. Bone-homing metastatic breast cancer cells impair osteocytes' mechanoresponse in a 3D loading model. Heliyon 2023; 9:e20248. [PMID: 37767467 PMCID: PMC10520780 DOI: 10.1016/j.heliyon.2023.e20248] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/23/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
Breast cancer predominantly metastasizes to the skeleton. Mechanical loading is reliably anabolic in bone, and also inhibits bone metastatic tumor formation and bone loss in vivo. To study the underlying mechanisms, we developed a 3D culture model for osteocytes, the primary bone mechanosensor. We verified that MLO-Y4s responded to perfusion by reducing their rankl and rankl:opg gene expression. We next cultured MLO-Y4s with tumor-conditioned media (TCM) collected from human breast cancer cells (MDA-MB-231s) and a corresponding bone-homing subclone to test the impacts on osteocytes' mechanosensation. We found that TCM from the bone-homing subclone was more detrimental to MLO-Y4 growth and viability, and it abrogated loading-induced changes to rankl:opg. Our studies demonstrate that MLO-Y4s, including their mechanoresponse to perfusion, were more negatively impacted by soluble factors from bone-homing breast cancer cells compared to those from parental cells.
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Affiliation(s)
- Blayne A. Sarazin
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, 80309, USA
| | - Boyuan Liu
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, 80309, USA
| | - Elaine Goldman
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, 80309, USA
| | - Ashlyn N. Whitefield
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, 80309, USA
| | - Maureen E. Lynch
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, 80309, USA
- BioFrontiers Institute, University of Colorado, Boulder, CO, 80309, USA
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4
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Frost K, Naylor AJ, McGettrick HM. The Ying and Yang of Sphingosine-1-Phosphate Signalling within the Bone. Int J Mol Sci 2023; 24:ijms24086935. [PMID: 37108099 PMCID: PMC10139073 DOI: 10.3390/ijms24086935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/28/2023] [Accepted: 04/04/2023] [Indexed: 04/29/2023] Open
Abstract
Bone remodelling is a highly active and dynamic process that involves the tight regulation of osteoblasts, osteoclasts, and their progenitors to allow for a balance of bone resorption and formation to be maintained. Ageing and inflammation are risk factors for the dysregulation of bone remodelling. Once the balance between bone formation and resorption is lost, bone mass becomes compromised, resulting in disorders such as osteoporosis and Paget's disease. Key molecules in the sphingosine-1-phosphate signalling pathway have been identified for their role in regulating bone remodelling, in addition to its more recognised role in inflammatory responses. This review discusses the accumulating evidence for the different, and, in certain circumstances, opposing, roles of S1P in bone homeostasis and disease, including osteoporosis, Paget's disease, and inflammatory bone loss. Specifically, we describe the current, often conflicting, evidence surrounding S1P function in osteoblasts, osteoclasts, and their precursors in health and disease, concluding that S1P may be an effective biomarker of bone disease and also an attractive therapeutic target for disease.
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Affiliation(s)
- Kathryn Frost
- Rheumatology Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2TT, UK
| | - Amy J Naylor
- Rheumatology Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2TT, UK
| | - Helen M McGettrick
- Rheumatology Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2TT, UK
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Mechanical Forces Govern Interactions of Host Cells with Intracellular Bacterial Pathogens. Microbiol Mol Biol Rev 2022; 86:e0009420. [PMID: 35285720 PMCID: PMC9199418 DOI: 10.1128/mmbr.00094-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
To combat infectious diseases, it is important to understand how host cells interact with bacterial pathogens. Signals conveyed from pathogen to host, and vice versa, may be either chemical or mechanical. While the molecular and biochemical basis of host-pathogen interactions has been extensively explored, relatively less is known about mechanical signals and responses in the context of those interactions. Nevertheless, a wide variety of bacterial pathogens appear to have developed mechanisms to alter the cellular biomechanics of their hosts in order to promote their survival and dissemination, and in turn many host responses to infection rely on mechanical alterations in host cells and tissues to limit the spread of infection. In this review, we present recent findings on how mechanical forces generated by host cells can promote or obstruct the dissemination of intracellular bacterial pathogens. In addition, we discuss how in vivo extracellular mechanical signals influence interactions between host cells and intracellular bacterial pathogens. Examples of such signals include shear stresses caused by fluid flow over the surface of cells and variable stiffness of the extracellular matrix on which cells are anchored. We highlight bioengineering-inspired tools and techniques that can be used to measure host cell mechanics during infection. These allow for the interrogation of how mechanical signals can modulate infection alongside biochemical signals. We hope that this review will inspire the microbiology community to embrace those tools in future studies so that host cell biomechanics can be more readily explored in the context of infection studies.
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Choi JUA, Kijas AW, Lauko J, Rowan AE. The Mechanosensory Role of Osteocytes and Implications for Bone Health and Disease States. Front Cell Dev Biol 2022; 9:770143. [PMID: 35265628 PMCID: PMC8900535 DOI: 10.3389/fcell.2021.770143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 12/13/2021] [Indexed: 12/14/2022] Open
Abstract
Bone homeostasis is a dynamic equilibrium between bone-forming osteoblasts and bone-resorbing osteoclasts. This process is primarily controlled by the most abundant and mechanosensitive bone cells, osteocytes, that reside individually, within chambers of porous hydroxyapatite bone matrix. Recent studies have unveiled additional functional roles for osteocytes in directly contributing to local matrix regulation as well as systemic roles through endocrine functions by communicating with distant organs such as the kidney. Osteocyte function is governed largely by both biochemical signaling and the mechanical stimuli exerted on bone. Mechanical stimulation is required to maintain bone health whilst aging and reduced level of loading are known to result in bone loss. To date, both in vivo and in vitro approaches have been established to answer important questions such as the effect of mechanical stimuli, the mechanosensors involved, and the mechanosensitive signaling pathways in osteocytes. However, our understanding of osteocyte mechanotransduction has been limited due to the technical challenges of working with these cells since they are individually embedded within the hard hydroxyapatite bone matrix. This review highlights the current knowledge of the osteocyte functional role in maintaining bone health and the key regulatory pathways of these mechanosensitive cells. Finally, we elaborate on the current therapeutic opportunities offered by existing treatments and the potential for targeting osteocyte-directed signaling.
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Affiliation(s)
- Jung Un Ally Choi
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Amanda W Kijas
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Jan Lauko
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Alan E Rowan
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
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7
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Leser JM, Harriot A, Buck HV, Ward CW, Stains JP. Aging, Osteo-Sarcopenia, and Musculoskeletal Mechano-Transduction. FRONTIERS IN REHABILITATION SCIENCES 2021; 2:782848. [PMID: 36004321 PMCID: PMC9396756 DOI: 10.3389/fresc.2021.782848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/10/2021] [Indexed: 11/13/2022]
Abstract
The decline in the mass and function of bone and muscle is an inevitable consequence of healthy aging with early onset and accelerated decline in those with chronic disease. Termed osteo-sarcopenia, this condition predisposes the decreased activity, falls, low-energy fractures, and increased risk of co-morbid disease that leads to musculoskeletal frailty. The biology of osteo-sarcopenia is most understood in the context of systemic neuro-endocrine and immune/inflammatory alterations that drive inflammation, oxidative stress, reduced autophagy, and cellular senescence in the bone and muscle. Here we integrate these concepts to our growing understanding of how bone and muscle senses, responds and adapts to mechanical load. We propose that age-related alterations in cytoskeletal mechanics alter load-sensing and mechano-transduction in bone osteocytes and muscle fibers which underscores osteo-sarcopenia. Lastly, we examine the evidence for exercise as an effective countermeasure to osteo-sarcopenia.
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Affiliation(s)
| | | | | | | | - Joseph P. Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States
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8
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Abstract
Bone fragility fractures remain an important worldwide health and economic problem due to increased morbidity and mortality. The current methods for predicting fractures are largely based on the measurement of bone mineral density and the utilization of mathematical risk calculators based on clinical risk factors for bone fragility. Despite these approaches, many bone fractures remain undiagnosed. Therefore, current research is focused on the identification of new factors such as bone turnover markers (BTM) for risk calculation. BTM are a group of proteins and peptides released during bone remodeling that can be found in serum or urine. They derive from bone resorptive and formative processes mediated by osteoclasts and osteoblasts, respectively. Potential use of BTM in monitoring these phenomenon and therefore bone fracture risk is limited by physiologic and pathophysiologic factors that influence BTM. These limitations in predicting fractures explain why their inclusion in clinical guidelines remains limited despite the large number of studies examining BTM.
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Affiliation(s)
- Lisa Di Medio
- Department of Surgery and Translational Medicine, University Hospital of Florence, Florence, Italy.
| | - Maria Luisa Brandi
- Department of Surgery and Translational Medicine, University Hospital of Florence, Florence, Italy
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9
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Mäkitie RE, Blouin S, Välimäki VV, Pihlström S, Määttä K, Pekkinen M, Fratzl-Zelman N, Mäkitie O, Hartmann MA. Abnormal Bone Tissue Organization and Osteocyte Lacunocanalicular Network in Early-Onset Osteoporosis Due to SGMS2 Mutations. JBMR Plus 2021; 5:e10537. [PMID: 34761145 PMCID: PMC8567487 DOI: 10.1002/jbm4.10537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 08/05/2021] [Indexed: 11/08/2022] Open
Abstract
Pathological variants in SGMS2, encoding sphingomyelin synthase 2 (SMS2), result in a rare autosomal dominant skeletal disorder with cranial doughnut lesions. The disease manifests as early-onset osteoporosis or a more severe skeletal dysplasia with low bone mineral density, frequent fractures, long-bone deformities, and multiple sclerotic cranial lesions. The exact underlying molecular features and skeletal consequences, however, remain elusive. This study investigated bone tissue characteristics in two adult males with a heterozygous SGMS2 mutation p.Arg50* and significant bone fragility. Transiliac bone biopsy samples from both (patient 1: 61 years; patient 2: 29 years) were analyzed by bone histomorphometry, confocal laser scanning microscopy, and quantitative backscattered electron imaging (qBEI). Bone histomorphometry portrayed largely normal values for structural and turnover parameters, but in both patient 1 and patient 2, respectively, osteoid thickness (-1.80 SD, -1.37 SD) and mineralizing surface (-1.03 SD, -2.73 SD) were reduced and osteoid surface increased (+9.03 SD, +0.98 SD), leading to elevated mineralization lag time (+8.16 SD, +4.10 SD). qBEI showed low and heterogeneous matrix mineralization (CaPeak -2.41 SD, -3.72 SD; CaWidth +7.47 SD, +4.41 SD) with a chaotic arrangement of collagenous fibrils under polarized light. Last, osteocyte lacunae appeared abnormally large and round in shape and the canalicular network severely disturbed with short-spanned canaliculi lacking any orderliness or continuity. Taken together, these data underline a central role for functional SMS2 in bone matrix organization and mineralization, lacunocanalicular network, and in maintaining skeletal strength and integrity. These data bring new knowledge on changes in bone histology resulting from abnormal sphingomyelin metabolism and aid en route to better understanding of sphingolipid-related skeletal disorders. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Riikka E Mäkitie
- Folkhälsan Institute of Genetics Helsinki Finland.,Research Program for Clinical and Molecular Metabolism, Faculty of Medicine University of Helsinki Helsinki Finland.,Department of Otorhinolaryngology-Head and Neck Surgery Helsinki University Hospital and University of Helsinki Helsinki Finland
| | - Stéphane Blouin
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital Vienna Austria.,Vienna Bone and Growth Center Vienna Austria
| | | | - Sandra Pihlström
- Folkhälsan Institute of Genetics Helsinki Finland.,Research Program for Clinical and Molecular Metabolism, Faculty of Medicine University of Helsinki Helsinki Finland
| | - Kirsi Määttä
- Folkhälsan Institute of Genetics Helsinki Finland.,Research Program for Clinical and Molecular Metabolism, Faculty of Medicine University of Helsinki Helsinki Finland
| | - Minna Pekkinen
- Folkhälsan Institute of Genetics Helsinki Finland.,Research Program for Clinical and Molecular Metabolism, Faculty of Medicine University of Helsinki Helsinki Finland.,Children's Hospital, University of Helsinki and Helsinki University Hospital Helsinki Finland
| | - Nadja Fratzl-Zelman
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital Vienna Austria.,Vienna Bone and Growth Center Vienna Austria
| | - Outi Mäkitie
- Folkhälsan Institute of Genetics Helsinki Finland.,Research Program for Clinical and Molecular Metabolism, Faculty of Medicine University of Helsinki Helsinki Finland.,Children's Hospital, University of Helsinki and Helsinki University Hospital Helsinki Finland.,Department of Molecular Medicine and Surgery and Center for Molecular Medicine Karolinska Institutet Stockholm Sweden
| | - Markus A Hartmann
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital Vienna Austria.,Vienna Bone and Growth Center Vienna Austria
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10
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Mechanisms of sphingosine-1-phosphate (S1P) signaling on excessive stress-induced root resorption during orthodontic molar intrusion. Clin Oral Investig 2021; 26:1003-1016. [PMID: 34363103 DOI: 10.1007/s00784-021-04084-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 07/15/2021] [Indexed: 12/16/2022]
Abstract
OBJECTIVES The aim of this study was to investigate cementocyte mechanotransduction during excessive orthodontic intrusive force-induced root resorption and the role of S1P signaling in this process. MATERIALS AND METHODS Fifty-four 12-week-old male Wistar rats were randomly divided into 3 groups: control group (Control), intrusive stress application group (Stress), and intrusive stress together with S1PR2-specific antagonist injection group (Stress + JTE). A rat molar intrusion model was established on animals in the Stress and the Stress + JTE groups. The animals in the Stress + JTE group received daily intraperitoneal (i.p.) injection of S1PR2 antagonist JTE-013, while the Control and Stress groups received only the vehicle. Histomorphometric, immunohistochemical, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analyses were performed after euthanizing of the rats. RESULTS Root resorption was promoted in the Stress group with increased volumes of resorption pits and amounts of molar intrusion compared with the Control group. The expression levels of cementogenic- and cementoclastic-related factors were affected under excessive intrusive force. Immunohistochemical staining and qRT-PCR analysis showed promoted S1P signaling activities during molar intrusion. Western blot analysis indicated decreased nuclear translocation of β-catenin under excessive intrusive force. Through the administration of JTE-013, S1P signaling activity was suppressed and excessive intrusive force-induced root resorption was reversed. The regulation of S1P signaling could also influence the nuclear translocation of β-catenin and the expressions of cementogenic- and cementoclastic-related factors. CONCLUSIONS Root resorption was promoted under excessive orthodontic intrusive force due to the disruption of cementum homeostasis. S1P signaling pathway might play an important role in cementocyte mechanotransduction in this process. CLINICAL RELEVANCE The S1P signaling might be a promising therapeutic target for novel therapeutic approaches to prevent external root resorption caused by excessive orthodontic intrusive force.
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11
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Li MCM, Chow SKH, Wong RMY, Qin L, Cheung WH. The role of osteocytes-specific molecular mechanism in regulation of mechanotransduction - A systematic review. J Orthop Translat 2021; 29:1-9. [PMID: 34036041 PMCID: PMC8138679 DOI: 10.1016/j.jot.2021.04.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/15/2021] [Accepted: 04/11/2021] [Indexed: 11/29/2022] Open
Abstract
Background Osteocytes, composing over 90% of bone cells, are well known for their mechanosensing abilities. Aged osteocytes with impaired morphology and function are less efficient in mechanotransduction which will disrupt bone turnover leading to osteoporosis. The aim of this systematic review is to delineate the mechanotransduction mechanism at different stages in order to explore potential target for therapeutic drugs. Methods A systematic literature search was performed in PubMed and Web of Science. Original animal, cell and clinical studies with available English full-text were included. Information was extracted from the included studies for review. Results The 26 studies included in this review provided evidence that mechanical loading are sensed by osteocytes via various sensing proteins and transduced to different signaling molecules which later initiate various biochemical responses. Studies have shown that osteocyte plasma membrane and cytoskeletons are emerging key players in initiating mechanotransduction. Bone regulating genes expressions are altered in response to load sensed by osteocytes, but the genes involved different signaling pathways and the spatiotemporal expression pattern had made mechanotransduction mechanism complicated. Most of the included studies described the important role of osteocytes in pathways that regulate mechanosensing and bone remodeling. Conclusions This systematic review provides an up-to-date insight to different steps of mechanotransduction. A better understanding of the mechanotransduction mechanism is beneficial in search of new potential treatment for osteoporotic patients. By delineating the unique morphology of osteocytes and their interconnected signaling network new targets can be discovered for drug development. Translational potential of this article This systematic review provides an up-to-date sequential overview and highlights the different osteocyte-related pathways and signaling molecules during mechanotransduction. This allows a better understanding of mechanotransduction for future development of new therapeutic interventions to treat patients with impaired mechanosensitivity.
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Affiliation(s)
- Meng Chen Michelle Li
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
| | - Simon Kwoon Ho Chow
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
- The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, PR China
| | - Ronald Man Yeung Wong
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
| | - Ling Qin
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
| | - Wing Hoi Cheung
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, China
- The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, PR China
- Corresponding author.Department of Orthopaedics and Traumatology, 5/F, Clinical Sciences Building, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
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12
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Sigdel I, Gupta N, Faizee F, Khare VM, Tiwari AK, Tang Y. Biomimetic Microfluidic Platforms for the Assessment of Breast Cancer Metastasis. Front Bioeng Biotechnol 2021; 9:633671. [PMID: 33777909 PMCID: PMC7992012 DOI: 10.3389/fbioe.2021.633671] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/05/2021] [Indexed: 12/27/2022] Open
Abstract
Of around half a million women dying of breast cancer each year, more than 90% die due to metastasis. Models necessary to understand the metastatic process, particularly breast cancer cell extravasation and colonization, are currently limited and urgently needed to develop therapeutic interventions necessary to prevent breast cancer metastasis. Microfluidic approaches aim to reconstitute functional units of organs that cannot be modeled easily in traditional cell culture or animal studies by reproducing vascular networks and parenchyma on a chip in a three-dimensional, physiologically relevant in vitro system. In recent years, microfluidics models utilizing innovative biomaterials and micro-engineering technologies have shown great potential in our effort of mechanistic understanding of the breast cancer metastasis cascade by providing 3D constructs that can mimic in vivo cellular microenvironment and the ability to visualize and monitor cellular interactions in real-time. In this review, we will provide readers with a detailed discussion on the application of the most up-to-date, state-of-the-art microfluidics-based breast cancer models, with a special focus on their application in the engineering approaches to recapitulate the metastasis process, including invasion, intravasation, extravasation, breast cancer metastasis organotropism, and metastasis niche formation.
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Affiliation(s)
- Indira Sigdel
- Biofluidics Laboratory, Department of Bioengineering, College of Engineering, University of Toledo, Toledo, OH, United States
| | - Niraj Gupta
- Biofluidics Laboratory, Department of Bioengineering, College of Engineering, University of Toledo, Toledo, OH, United States
| | - Fairuz Faizee
- Biofluidics Laboratory, Department of Bioengineering, College of Engineering, University of Toledo, Toledo, OH, United States
| | - Vishwa M Khare
- Eurofins Lancaster Laboratories, Philadelphia, PA, United States
| | - Amit K Tiwari
- Department of Pharmacology and Experimental Therapeutics, College of Pharmacy & Pharmaceutical Sciences, University of Toledo, Toledo, OH, United States
| | - Yuan Tang
- Biofluidics Laboratory, Department of Bioengineering, College of Engineering, University of Toledo, Toledo, OH, United States
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13
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Mansoorifar A, Gordon R, Bergan R, Bertassoni LE. Bone-on-a-chip: microfluidic technologies and microphysiologic models of bone tissue. ADVANCED FUNCTIONAL MATERIALS 2021; 31:2006796. [PMID: 35422682 PMCID: PMC9007546 DOI: 10.1002/adfm.202006796] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Indexed: 05/07/2023]
Abstract
Bone is an active organ that continuously undergoes an orchestrated process of remodeling throughout life. Bone tissue is uniquely capable of adapting to loading, hormonal, and other changes happening in the body, as well as repairing bone that becomes damaged to maintain tissue integrity. On the other hand, diseases such as osteoporosis and metastatic cancers disrupt normal bone homeostasis leading to compromised function. Historically, our ability to investigate processes related to either physiologic or diseased bone tissue has been limited by traditional models that fail to emulate the complexity of native bone. Organ-on-a-chip models are based on technological advances in tissue engineering and microfluidics, enabling the reproduction of key features specific to tissue microenvironments within a microfabricated device. Compared to conventional in-vitro and in-vivo bone models, microfluidic models, and especially organs-on-a-chip platforms, provide more biomimetic tissue culture conditions, with increased predictive power for clinical assays. In this review, we will report microfluidic and organ-on-a-chip technologies designed for understanding the biology of bone as well as bone-related diseases and treatments. Finally, we discuss the limitations of the current models and point toward future directions for microfluidics and organ-on-a-chip technologies in bone research.
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Affiliation(s)
- Amin Mansoorifar
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - Ryan Gordon
- Division of Hematology/Oncology, Knight Cancer Institute, Oregon Health & Science University, Portland, OR, USA
| | - Raymond Bergan
- Division of Hematology/Oncology, Knight Cancer Institute, Oregon Health & Science University, Portland, OR, USA
| | - Luiz E. Bertassoni
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
- Center for Regenerative Medicine, School of Medicine, Oregon Health & Science University, Portland, OR, USA
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, OR, USA
- Cancer Early Detection Advanced Research Center (CEDAR), Knight Cancer Institute, Portland, OR, USA
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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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15
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Targeting Mechanotransduction in Osteosarcoma: A Comparative Oncology Perspective. Int J Mol Sci 2020; 21:ijms21207595. [PMID: 33066583 PMCID: PMC7589883 DOI: 10.3390/ijms21207595] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022] Open
Abstract
Mechanotransduction is the process in which cells can convert extracellular mechanical stimuli into biochemical changes within a cell. While this a normal process for physiological development and function in many organ systems, tumour cells can exploit this process to promote tumour progression. Here we summarise the current state of knowledge of mechanotransduction in osteosarcoma (OSA), the most common primary bone tumour, referencing both human and canine models and other similar mesenchymal malignancies (e.g., Ewing sarcoma). Specifically, we discuss the mechanical properties of OSA cells, the pathways that these cells utilise to respond to external mechanical cues, and mechanotransduction-targeting strategies tested in OSA so far. We point out gaps in the literature and propose avenues to address them. Understanding how the physical microenvironment influences cell signalling and behaviour will lead to the improved design of strategies to target the mechanical vulnerabilities of OSA cells.
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16
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Lewis KJ, Yi X, Wright CS, Pemberton EZ, Bullock WA, Thompson WR, Robling AG. The mTORC2 Component Rictor Is Required for Load-Induced Bone Formation in Late-Stage Skeletal Cells. JBMR Plus 2020; 4:e10366. [PMID: 32666017 PMCID: PMC7340445 DOI: 10.1002/jbm4.10366] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 03/17/2020] [Indexed: 12/14/2022] Open
Abstract
Bone relies on mechanical cues to build and maintain tissue composition and architecture. Our understanding of bone cell mechanotransduction continues to evolve, with a few key signaling pathways emerging as vital. Wnt/β‐catenin, for example, is essential for proper anabolic response to mechanical stimulation. One key complex that regulates β‐catenin activity is the mammalian target of rapamycin complex 2 (mTORc2). mTORc2 is critical for actin cytoskeletal reorganization, an indispensable component in mechanotransduction in certain cell types. In this study, we probed the impact of the mTORc2 signaling pathway in osteocyte mechanotransduction by conditionally deleting the mTORc2 subunit Rictor in Dmp1‐expressing cells of C57BL/6 mice. Conditional deletion of the Rictor was achieved using the Dmp1–Cre driver to recombine Rictor floxed alleles. Rictor mutants exhibited a decrease in skeletal properties, as measured by DXA, μCT, and mechanical testing, compared with Cre‐negative floxed littermate controls. in vivo axial tibia loading conducted in adult mice revealed a deficiency in the osteogenic response to loading among Rictor mutants. Histological measurements of osteocyte morphology indicated fewer, shorter cell processes in Rictor mutants, which might explain the compromised response to mechanical stimulation. In summary, inhibition of the mTORc2 pathway in late osteoblasts/osteocytes leads to decreased bone mass and mechanically induced bone formation. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Karl J Lewis
- Department of Anatomy & Cell Biology Indiana University School of Medicine Indianapolis IN USA
| | - Xin Yi
- Department of Physical Therapy Indiana University School of Health & Human Sciences Indianapolis IN USA
| | - Christian S Wright
- Department of Physical Therapy Indiana University School of Health & Human Sciences Indianapolis IN USA
| | - Emily Z Pemberton
- Department of Anatomy & Cell Biology Indiana University School of Medicine Indianapolis IN USA
| | - Whitney A Bullock
- Department of Anatomy & Cell Biology Indiana University School of Medicine Indianapolis IN USA
| | - William R Thompson
- Department of Physical Therapy Indiana University School of Health & Human Sciences Indianapolis IN USA.,Indiana Center for Musculoskeletal Health Indianapolis IN USA
| | - Alexander G Robling
- Department of Anatomy & Cell Biology Indiana University School of Medicine Indianapolis IN USA.,Indiana Center for Musculoskeletal Health Indianapolis IN USA.,Department of Biomedical Engineering Indiana University-Purdue University at Indianapolis Indianapolis IN USA.,Richard L. Roudebush VA Medical Center Indianapolis IN USA
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17
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Yan Y, Wang L, Ge L, Pathak JL. Osteocyte-Mediated Translation of Mechanical Stimuli to Cellular Signaling and Its Role in Bone and Non-bone-Related Clinical Complications. Curr Osteoporos Rep 2020; 18:67-80. [PMID: 31953640 DOI: 10.1007/s11914-020-00564-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW Osteocytes comprise > 95% of the cellular component in bone tissue and produce a wide range of cytokines and cellular signaling molecules in response to mechanical stimuli. In this review, we aimed to summarize the molecular mechanisms involved in the osteocyte-mediated translation of mechanical stimuli to cellular signaling, and discuss their role in skeletal (bone) diseases and extra-skeletal (non-bone) clinical complications. RECENT FINDINGS Two decades before, osteocytes were assumed as a dormant cells buried in bone matrix. In recent years, emerging evidences have shown that osteocytes are pivotal not only for bone homeostasis but also for vital organ functions such as muscle, kidney, and heart. Osteocyte mechanotransduction regulates osteoblast and osteoclast function and maintains bone homeostasis. Mechanical stimuli modulate the release of osteocyte-derived cytokines, signaling molecules, and extracellular cellular vesicles that regulate not only the surrounding bone cell function and bone homeostasis but also the distant organ function in a paracrine and endocrine fashion. Mechanical loading and unloading modulate the osteocytic release of NO, PGE2, and ATPs that regulates multiple cellular signaling such as Wnt/β-catenin, RANKL/OPG, BMPs, PTH, IGF1, VEGF, sclerostin, and others. Therefore, the in-depth study of the molecular mechanism of osteocyte mechanotransduction could unravel therapeutic targets for various bone and non-bone-related clinical complications such as osteoporosis, sarcopenia, and cancer metastasis to bone.
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Affiliation(s)
- Yongyong Yan
- Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, 510140, China
| | - Liping Wang
- Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, 510140, China
| | - Linhu Ge
- Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, 510140, China.
| | - Janak L Pathak
- Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, 510140, China.
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18
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Wang H, Li T, Wang X, Yin X, Zhao N, Zou S, Duan P, Bonewald LF. The role of sphingosine-1-phosphate signaling pathway in cementocyte mechanotransduction. Biochem Biophys Res Commun 2020; 523:595-601. [PMID: 31941604 DOI: 10.1016/j.bbrc.2020.01.003] [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: 12/13/2019] [Accepted: 01/02/2020] [Indexed: 02/08/2023]
Abstract
Iatrogenic external root resorption can become a serious pathological condition with clinical tooth movement. Little is known regarding how cementum responds to mechanical loading in contrast to bone, especially under compressive stress. In the field of bone biology, several studies have established the contribution of sphingosine-1-phosphate (S1P) signaling in bone remodeling, mechanical transduction and homeostasis. As osteocytes and cementocytes share similar morphological and functional characteristics, this study aimed to investigate the mechanotransduction ability of cementocytes and to explore the contribution of S1P signaling under compressive stress induced mechanotransduction. We found that compressive stress inhibited major S1P signaling and promoted the expression of anabolic factors in IDG-CM6 cells, a novel immortalized murine cementocyte cell line. By inhibiting S1P signaling, we verified that S1P signaling played a vital role in regulating the expression of the mechanotransduction factors prostaglandin E2 (PGE2) and β-catenin, as well as factors responsible for cementogenesis and cementoclastogenesis in IDG-CM6 cells. These results support the hypothesis that cementocytes act as key mechanically responsive cells in cementum, responding to compressive stress and directing local cementum metabolism.
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Affiliation(s)
- Han Wang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Tiancheng Li
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Xin Wang
- Oral Diagnosis and Treatment Center, Aviation General Hospital, China Medical University, Beijing, China
| | - Xing Yin
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Ning Zhao
- Department of Orthodontics, Shanghai Key Laboratory of Stomatology, Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shujuan Zou
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Peipei Duan
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
| | - Lynda F Bonewald
- Departments of Anatomy, Cell Biology & Physiology and Orthopaedic Surgery, Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States
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19
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Pathak JL, Bravenboer N, Klein-Nulend J. The Osteocyte as the New Discovery of Therapeutic Options in Rare Bone Diseases. Front Endocrinol (Lausanne) 2020; 11:405. [PMID: 32733380 PMCID: PMC7360678 DOI: 10.3389/fendo.2020.00405] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 05/20/2020] [Indexed: 01/18/2023] Open
Abstract
Osteocytes are the most abundant (~95%) cells in bone with the longest half-life (~25 years) in humans. In the past osteocytes have been regarded as vestigial cells in bone, since they are buried inside the tough bone matrix. However, during the last 30 years it has become clear that osteocytes are as important as bone forming osteoblasts and bone resorbing osteoclasts in maintaining bone homeostasis. The osteocyte cell body and dendritic processes reside in bone in a complex lacuno-canalicular system, which allows the direct networking of osteocytes to their neighboring osteocytes, osteoblasts, osteoclasts, bone marrow, blood vessels, and nerves. Mechanosensing of osteocytes translates the applied mechanical force on bone to cellular signaling and regulation of bone adaptation. The osteocyte lacuno-canalicular system is highly efficient in transferring external mechanical force on bone to the osteocyte cell body and dendritic processes via displacement of fluid in the lacuno-canalicular space. Osteocyte mechanotransduction regulates the formation and function of the osteoblasts and osteoclasts to maintain bone homeostasis. Osteocytes produce a variety of proteins and signaling molecules such as sclerostin, cathepsin K, Wnts, DKK1, DMP1, IGF1, and RANKL/OPG to regulate osteoblast and osteoclast activity. Various genetic abnormality-associated rare bone diseases are related to disrupted osteocyte functions, including sclerosteosis, van Buchem disease, hypophosphatemic rickets, and WNT1 and plastin3 mutation-related disorders. Meticulous studies during the last 15 years on disrupted osteocyte function in rare bone diseases guided for the development of various novel therapeutic agents to treat bone diseases. Studies on genetic, molecular, and cellular mechanisms of sclerosteosis and van Buchem disease revealed a role for sclerostin in bone homeostasis, which led to the development of the sclerostin antibody to treat osteoporosis and other bone degenerative diseases. The mechanism of many other rare bone diseases and the role of the osteocyte in the development of such conditions still needs to be investigated. In this review, we mainly discuss the knowledge obtained during the last 30 years on the role of the osteocyte in rare bone diseases. We speculate about future research directions to develop novel therapeutic drugs targeting osteocyte functions to treat both common and rare bone diseases.
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Affiliation(s)
- Janak L. Pathak
- Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Nathalie Bravenboer
- Department of Clinical Chemistry, Amsterdam University Medical Centers, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Jenneke Klein-Nulend
- Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam, Amsterdam Movement Sciences, University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- *Correspondence: Jenneke Klein-Nulend
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20
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El Jamal A, Briolay A, Mebarek S, Le Goff B, Blanchard F, Magne D, Brizuela L, Bougault C. Cytokine-Induced and Stretch-Induced Sphingosine 1-Phosphate Production by Enthesis Cells Could Favor Abnormal Ossification in Spondyloarthritis. J Bone Miner Res 2019; 34:2264-2276. [PMID: 31373726 DOI: 10.1002/jbmr.3844] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 07/11/2019] [Accepted: 07/19/2019] [Indexed: 12/12/2022]
Abstract
Spondyloarthritis (SpA) is a common rheumatic disease characterized by enthesis inflammation (enthesitis) and ectopic ossification (enthesophytes). The current pathogenesis model suggests that inflammation and mechanical stress are both strongly involved in SpA pathophysiology. We have previously observed that the levels of sphingosine 1-phosphate (S1P), a bone anabolic molecule, were particularly high in SpA patients' serum compared to healthy donors. Therefore, we wondered how this deregulation was related to SpA molecular mechanisms. Mouse primary osteoblasts, chondrocytes, and tenocytes were used as cell culture models. The sphingosine kinase 1 (Sphk1) gene expression and S1P secretion were significantly enhanced by cyclic stretch in osteoblasts and chondrocytes. Further, TNF-α and IL-17, cytokines implicated in enthesitis, increased Sphk1 mRNA in chondrocytes in an additive manner when combined to stretch. The immunochemistry on mouse ankles showed that sphingosine kinase 1 (SK1) was localized in some chondrocytes; the addition of a pro-inflammatory cocktail augmented Sphk1 expression in cultured ankles. Subsequently, fingolimod was used to block S1P metabolism in cell cultures. It inhibited S1P receptors (S1PRs) signaling and SK1 and SK2 activity in both osteoblasts and chondrocytes. Fingolimod also reduced S1PR-induced activation by SpA patients' synovial fluid (SF), demonstrating that the stimulation of chondrocytes by SFs from SpA patients involves S1P. In addition, when the osteogenic culture medium was supplemented with fingolimod, alkaline phosphatase activity, matrix mineralization, and bone formation markers were significantly reduced in osteoblasts and hypertrophic chondrocytes. Osteogenic differentiation was accompanied by an increase in S1prs mRNA, especially S1P1/3 , but their contribution to S1P-impact on mineralization seemed limited. Our results suggest that S1P might be overproduced in SpA enthesis in response to cytokines and mechanical stress, most likely by chondrocytes. Moreover, S1P could locally favor the abnormal ossification of the enthesis; therefore, blocking the S1P metabolic pathway could be a potential therapeutic approach for the treatment of SpA. © 2019 American Society for Bone and Mineral Research.
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Affiliation(s)
- Alaeddine El Jamal
- Univ Lyon, Univ Claude Bernard Lyon 1 (UCBL), CNRS, UMR5246, Lyon, France
| | - Anne Briolay
- Univ Lyon, Univ Claude Bernard Lyon 1 (UCBL), CNRS, UMR5246, Lyon, France
| | - Saida Mebarek
- Univ Lyon, Univ Claude Bernard Lyon 1 (UCBL), CNRS, UMR5246, Lyon, France
| | - Benoit Le Goff
- INSERM UMR1238, Nantes University, Nantes, France.,Rheumatology Department, Nantes University, Nantes, France
| | | | - David Magne
- Univ Lyon, Univ Claude Bernard Lyon 1 (UCBL), CNRS, UMR5246, Lyon, France
| | - Leyre Brizuela
- Univ Lyon, Univ Claude Bernard Lyon 1 (UCBL), CNRS, UMR5246, Lyon, France
| | - Carole Bougault
- Univ Lyon, Univ Claude Bernard Lyon 1 (UCBL), CNRS, UMR5246, Lyon, France
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21
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Mei X, Middleton K, Shim D, Wan Q, Xu L, Ma YHV, Devadas D, Walji N, Wang L, Young EWK, You L. Microfluidic platform for studying osteocyte mechanoregulation of breast cancer bone metastasis. Integr Biol (Camb) 2019; 11:119-129. [DOI: 10.1093/intbio/zyz008] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/27/2019] [Accepted: 05/02/2019] [Indexed: 11/12/2022]
Abstract
AbstractBone metastasis is a common, yet serious, complication of breast cancer. Breast cancer cells that extravasate from blood vessels to the bone devastate bone quality by interacting with bone cells and disrupting the bone remodeling balance. Although exercise is often suggested as a cancer intervention strategy and mechanical loading during exercise is known to regulate bone remodeling, its role in preventing bone metastasis remains unknown. We developed a novel in vitro microfluidic tissue model to investigate the role of osteocytes in the mechanical regulation of breast cancer bone metastasis. Metastatic MDA-MB-231 breast cancer cells were cultured inside a 3D microfluidic lumen lined with human umbilical vein endothelial cells (HUVECs), which is adjacent to a channel seeded with osteocyte-like MLO-Y4 cells. Physiologically relevant oscillatory fluid flow (OFF) (1 Pa, 1 Hz) was applied to mechanically stimulate the osteocytes. Hydrogel-filled side channels in-between the two channels allowed real-time, bi-directional cellular signaling and cancer cell extravasation over 3 days. The applied OFF was capable of inducing intracellular calcium responses in osteocytes (82.3% cells responding with a 3.71 fold increase average magnitude). Both extravasation distance and percentage of extravasated side-channels were significantly reduced with mechanically stimulated osteocytes (32.4% and 53.5% of control, respectively) compared to static osteocytes (102.1% and 107.3% of control, respectively). This is the first microfluidic device that has successfully integrated stimulatory bone fluid flow, and demonstrated that mechanically stimulated osteocytes reduced breast cancer extravasation. Future work with this platform will determine the specific mechanisms involved in osteocyte mechanoregulation of breast cancer bone metastasis, as well as other types of cancer metastasis and diseases.
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Affiliation(s)
- Xueting Mei
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Kevin Middleton
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Dongsub Shim
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Qianqian Wan
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Liangcheng Xu
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Yu-Heng Vivian Ma
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Deepika Devadas
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Noosheen Walji
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Liyun Wang
- Department of Mechanical Engineering, University of Delaware
| | - Edmond W K Young
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Lidan You
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
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22
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Ma YHV, Xu L, Mei X, Middleton K, You L. Mechanically stimulated osteocytes reduce the bone-metastatic potential of breast cancer cells in vitro by signaling through endothelial cells. J Cell Biochem 2019; 120:7590-7601. [PMID: 30417549 DOI: 10.1002/jcb.28034] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 10/15/2018] [Indexed: 01/24/2023]
Abstract
Bone metastases occur in 65% to 75% of patients with advanced breast cancer and significantly worsen their survival and quality of life. We previously showed that conditioned medium (CM) from osteocytes stimulated with oscillatory fluid flow, mimicking bone mechanical loading during routine physical activities, reduced the transendothelial migration of breast cancer cells. Endothelial cells are situated at an ideal location to mediate signals between osteocytes in the bone matrix and metastasizing cancer cells in the blood vessels. In this study, we investigated the specific effects of flow-stimulated osteocytes on the interaction between endothelial cells and breast cancer cells in vitro. We observed that CM from flow-stimulated osteocytes reduced endothelial permeability by 15% and breast cancer cell adhesion onto endothelial monolayers by 18%. The difference in adhesion was abolished with anti-intercellular adhesion molecule 1 (ICAM-1) neutralizing antibodies. Furthermore, CM from endothelial cells conditioned in CM from flow-stimulated osteocytes significantly altered the gene expression in bone-metastatic breast cancer cells, as shown by RNA sequencing. Specifically, breast cancer cell expression of matrix metallopeptidase 9 (MMP-9) was downregulated by 62%, and frizzled-4 (FZD4) by 61%, when the osteocytes were stimulated with flow. The invasion of these breast cancer cells across Matrigel was also reduced by 47%, and this difference was abolished by MMP-9 inhibitors. In conclusion, we demonstrated that flow-stimulated osteocytes downregulate the bone-metastatic potential of breast cancer cells by signaling through endothelial cells. This provides insights into the capability of bone mechanical regulation in preventing bone metastases; and may assist in prescribing exercise or bone-loading regimens to patients with breast cancers.
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Affiliation(s)
- Yu-Heng Vivian Ma
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Liangcheng Xu
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Xueting Mei
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Kevin Middleton
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Lidan You
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.,Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
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23
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Peltier L, Bendavid C, Cavey T, Island ML, Doyard M, Leroyer P, Allain C, De Tayrac M, Ropert M, Loréal O, Guggenbuhl P. Iron excess upregulates SPNS2 mRNA levels but reduces sphingosine-1-phosphate export in human osteoblastic MG-63 cells. Osteoporos Int 2018; 29:1905-1915. [PMID: 29721575 DOI: 10.1007/s00198-018-4531-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 04/11/2018] [Indexed: 02/06/2023]
Abstract
UNLABELLED We aimed to study the mechanisms involved in bone-related iron impairment by using the osteoblast-like MG-63 cell line. Our results indicate that iron impact the S1P/S1PR signalizing axis and suggest that iron can affect the S1P process and favor the occurrence of osteoporosis during chronic iron overload. INTRODUCTION Systemic iron excess favors the development of osteoporosis, especially during genetic hemochromatosis. The cellular mechanisms involved are still unclear despite numerous data supporting a direct effect of iron on bone biology. Therefore, the aim of this study was to characterize mechanisms involved in the iron-related osteoblast impairment. METHODS We studied, by using the MG-63 cell lines, the effect of iron excess on SPNS2 gene expression which was previously identified by us as potentially iron-regulated. Cell-type specificity was investigated with hepatoma HepG2 and enterocyte-like Caco-2 cell lines as well as in iron-overloaded mouse liver. The SPNS2-associated function was also investigated in MG-63 cells by fluxomic strategy which led us to determinate the S1P efflux in iron excess condition. RESULTS We showed in MG-63 cells that iron exposure strongly increased the mRNA level of the SPNS2 gene. This was not observed in HepG2, in Caco-2 cells, and in mouse livers. Fluxomic study performed concomitantly on MG-63 cells revealed an unexpected decrease in the cellular capacity to export S1P. Iron excess did not modulate SPHK1, SPHK2, SGPL1, or SGPP1 gene expression, but decreased COL1A1 and S1PR1 mRNA levels, suggesting a functional implication of low extracellular S1P concentration on the S1P/S1PR signalizing axis. CONCLUSIONS Our results indicate that iron impacts the S1P/S1PR signalizing axis in the MG-63 cell line and suggest that iron can affect the bone-associated S1P pathway and favor the occurrence of osteoporosis during chronic iron overload.
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Affiliation(s)
- L Peltier
- Service de Biochimie - Toxicologie, CHU Rennes, F-35033, Rennes, France
- INSERM, INRA, Univ Rennes1, Univ Bretagne Loire, Nutrition, Metabolism, and Cancer, Rennes, France
- Faculté de Médecine, Université Rennes 1, F-35043, Rennes, France
| | - C Bendavid
- Service de Biochimie - Toxicologie, CHU Rennes, F-35033, Rennes, France
- INSERM, INRA, Univ Rennes1, Univ Bretagne Loire, Nutrition, Metabolism, and Cancer, Rennes, France
- Faculté de Médecine, Université Rennes 1, F-35043, Rennes, France
| | - T Cavey
- Service de Biochimie - Toxicologie, CHU Rennes, F-35033, Rennes, France
- INSERM, INRA, Univ Rennes1, Univ Bretagne Loire, Nutrition, Metabolism, and Cancer, Rennes, France
- Faculté de Médecine, Université Rennes 1, F-35043, Rennes, France
| | - M-L Island
- INSERM, INRA, Univ Rennes1, Univ Bretagne Loire, Nutrition, Metabolism, and Cancer, Rennes, France
| | - M Doyard
- INSERM, INRA, Univ Rennes1, Univ Bretagne Loire, Nutrition, Metabolism, and Cancer, Rennes, France
| | - P Leroyer
- INSERM, INRA, Univ Rennes1, Univ Bretagne Loire, Nutrition, Metabolism, and Cancer, Rennes, France
| | - C Allain
- INSERM, INRA, Univ Rennes1, Univ Bretagne Loire, Nutrition, Metabolism, and Cancer, Rennes, France
| | - M De Tayrac
- Faculté de Médecine, Université Rennes 1, F-35043, Rennes, France
- CNRS, UMR 6290, Institut de Génétique et Développement de Rennes (IGdR), F-35043, Rennes, France
- Service de Génétique Moléculaire et Génomique, CHU Rennes, F-35033, Rennes, France
| | - M Ropert
- Service de Biochimie - Toxicologie, CHU Rennes, F-35033, Rennes, France
- INSERM, INRA, Univ Rennes1, Univ Bretagne Loire, Nutrition, Metabolism, and Cancer, Rennes, France
| | - O Loréal
- INSERM, INRA, Univ Rennes1, Univ Bretagne Loire, Nutrition, Metabolism, and Cancer, Rennes, France
| | - P Guggenbuhl
- INSERM, INRA, Univ Rennes1, Univ Bretagne Loire, Nutrition, Metabolism, and Cancer, Rennes, France.
- Faculté de Médecine, Université Rennes 1, F-35043, Rennes, France.
- Service de Rhumatologie, CHU Rennes, F-35203, Rennes, France.
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24
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Yan Z, Wang P, Wu J, Feng X, Cai J, Zhai M, Li J, Liu X, Jiang M, Luo E, Jing D. Fluid shear stress improves morphology, cytoskeleton architecture, viability, and regulates cytokine expression in a time-dependent manner in MLO-Y4 cells. Cell Biol Int 2018; 42:1410-1422. [DOI: 10.1002/cbin.11032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/13/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Zedong Yan
- Department of Biomedical Engineering; Fourth Military Medical University; Xi'an China
| | - Pan Wang
- Department of Biomedical Engineering; Fourth Military Medical University; Xi'an China
| | - Junjie Wu
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Clinical Research Center for Oral Diseases; Department of Orthodontics; School of Stomatology; Fourth Military Medical University; Xi'an China
| | - Xue Feng
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Clinical Research Center for Oral Diseases; Department of Orthodontics; School of Stomatology; Fourth Military Medical University; Xi'an China
| | - Jing Cai
- College of Basic Medicine; Shaanxi University of Chinese Medicine; Xianyang China
| | - Mingming Zhai
- Department of Biomedical Engineering; Fourth Military Medical University; Xi'an China
| | - Juan Li
- Department of Neurosurgery; Xijing Hospital; Fourth Military Medical University; Xi'an China
| | - Xiyu Liu
- Department of Biomedical Engineering; Fourth Military Medical University; Xi'an China
| | - Maogang Jiang
- Department of Biomedical Engineering; Fourth Military Medical University; Xi'an China
| | - Erping Luo
- Department of Biomedical Engineering; Fourth Military Medical University; Xi'an China
| | - Da Jing
- Department of Biomedical Engineering; Fourth Military Medical University; Xi'an China
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25
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Ma YV, Lam C, Dalmia S, Gao P, Young J, Middleton K, Liu C, Xu H, You L. Mechanical regulation of breast cancer migration and apoptosis via direct and indirect osteocyte signaling. J Cell Biochem 2018; 119:5665-5675. [DOI: 10.1002/jcb.26745] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 01/29/2018] [Indexed: 01/01/2023]
Affiliation(s)
- Yu‐Heng V. Ma
- Institute of Biomaterials and Biomedical EngineeringUniversity of TorontoTorontoOntarioCanada
| | - Candy Lam
- Institute of Biomaterials and Biomedical EngineeringUniversity of TorontoTorontoOntarioCanada
| | - Shreyash Dalmia
- Institute of Biomaterials and Biomedical EngineeringUniversity of TorontoTorontoOntarioCanada
| | - Peter Gao
- Institute of Biomaterials and Biomedical EngineeringUniversity of TorontoTorontoOntarioCanada
| | - Jacob Young
- Institute of Biomaterials and Biomedical EngineeringUniversity of TorontoTorontoOntarioCanada
| | - Kevin Middleton
- Institute of Biomaterials and Biomedical EngineeringUniversity of TorontoTorontoOntarioCanada
| | - Chao Liu
- Institute of Biomaterials and Biomedical EngineeringUniversity of TorontoTorontoOntarioCanada
| | - Henry Xu
- Institute of Biomaterials and Biomedical EngineeringUniversity of TorontoTorontoOntarioCanada
| | - Lidan You
- Institute of Biomaterials and Biomedical EngineeringUniversity of TorontoTorontoOntarioCanada
- Department of Mechanical and Industrial EngineeringUniversity of TorontoTorontoOntarioCanada
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26
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Middleton K, Kondiboyina A, Borrett M, Cui Y, Mei X, You L. Microfluidics approach to investigate the role of dynamic similitude in osteocyte mechanobiology. J Orthop Res 2018; 36:663-671. [PMID: 29027748 DOI: 10.1002/jor.23773] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 10/06/2017] [Indexed: 02/04/2023]
Abstract
Fluid flow is an important regulator of cell function and metabolism in many tissues. Fluid shear stresses have been used to level the mechanical stimuli applied in vitro with what occurs in vivo. However, these experiments often lack dynamic similarity, which is necessary to ensure the validity of the model. For interstitial fluid flow, the major requirement for dynamic similarity is the Reynolds number (Re), the ratio of inertial to viscous forces, is the same between the system and model. To study the necessity of dynamic similarity for cell mechanotransduction studies, we investigated the response of osteocyte-like MLO-Y4 cells to different Re flows at the same level of fluid shear stress. Osteocytes were chosen for this study as flows applied in vitro and in vivo have Re that are orders of magnitude different. We hypothesize that osteocytes' response to fluid flow is Re dependent. We observed that cells exposed to lower and higher Re flows developed rounded and triangular morphologies, respectively. Lower Re flows also reduced apoptosis rates compared to higher Re flows. Furthermore, MLO-Y4 cells exposed to higher Re flows had stronger calcium responses compared to lower Re flows. However, by also controlling for flow rate, the lower Re flows induced a stronger calcium response; while degradation of components of the osteocyte glycocalyx reversed this effect. This work suggests that osteocytes are highly sensitive to differences in Re, independent of just shear stresses, supporting the need for improved in vitro flow platforms that better recapitulate the physiological environment. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:663-671, 2018.
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Affiliation(s)
- Kevin Middleton
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Room 407, Toronto, Ontario, M5S 3G9, Canada
| | - Avinash Kondiboyina
- Division of Engineering Science, University of Toronto, 40 Saint George Street, Room 2110, Toronto, Ontario, M5S 2E4, Canada
| | - Michael Borrett
- Department of Biochemistry, McMaster University, 1280 Main Street West, Room 4N59, Hamilton, Ontario, L8S 4L8, Canada
| | - Yi Cui
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Room 105, Toronto, Ontario, M5S 3G8, Canada
| | - Xueting Mei
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Room 105, Toronto, Ontario, M5S 3G8, Canada
| | - Lidan You
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Room 407, Toronto, Ontario, M5S 3G9, Canada.,Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Room 105, Toronto, Ontario, M5S 3G8, Canada
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27
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Dobrosak C, Gooi JH. Increased sphingosine-1-phosphate production in response to osteocyte mechanotransduction. Bone Rep 2017; 7:114-120. [PMID: 29085869 PMCID: PMC5651498 DOI: 10.1016/j.bonr.2017.10.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/06/2017] [Accepted: 10/15/2017] [Indexed: 01/01/2023] Open
Abstract
Over the past few years interest has greatly increased in how the lipid mediator sphingosine-1-phosphate (S1P) influences bone homeostasis. Recent work has postulated multiple effects of S1P on osteoblasts and osteoclasts. Based on these findings, S1P has been proposed as a potential osteoporosis treatment. However, to date, there has been only a single study investigating S1P signalling in the cells that co-ordinate bone metabolism: osteocytes. This study aimed to elucidate the role of S1P signalling in osteocyte mechanotransduction. Utilising 3D cell culture we established the expression profile of all genes related to the S1P signalling system in the Ocy454 osteocyte cell line. Exposure to mechanical loading resulted in a downregulation in Sost, Spns2, the S1P transporter, Sgpl1 and Sgppl1 the enzymes responsible for degradation and dephosphorylation of S1P. These findings, in conjunction with fluid-flow induced upregulation of Sphk1, the kinase responsible for phosphorylation of sphingosine, suggest that mechanical stimulation of osteocytes leads to an increase in intracellular S1P. This was confirmed with mechanical loading of Ocy454 cells rapidly increasing S1P production in conditioned media and protein lysates. These findings strongly suggest an important role for S1P in the response to mechanical loading of bone. Osteocytes form a cellular network throughout bone ideally suited for sensing the needs of the skeleton and responding to them. Over the past few years interest has greatly increased in how S1P influences bone homeostasis. Exposure to mechanical loading significantly modifies osteocyte S1P signalling. This suggests an important role for S1P production in the response to mechanical loading of bone.
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Affiliation(s)
- Cale Dobrosak
- Department of Medicine, St. Vincent's Hospital Melbourne, University of Melbourne, Melbourne, VIC 3065, Australia
| | - Jonathan H Gooi
- Department of Medicine, St. Vincent's Hospital Melbourne, University of Melbourne, Melbourne, VIC 3065, Australia
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28
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Sphingosine 1-phosphate (S1P) signalling: Role in bone biology and potential therapeutic target for bone repair. Pharmacol Res 2017; 125:232-245. [PMID: 28855094 DOI: 10.1016/j.phrs.2017.08.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 08/22/2017] [Accepted: 08/23/2017] [Indexed: 12/30/2022]
Abstract
The lipid mediator sphingosine 1-phosphate (S1P) affects cellular functions in most systems. Interest in its therapeutic potential has increased following the discovery of its G protein-coupled receptors and the recent availability of agents that can be safely administered in humans. Although the role of S1P in bone biology has been the focus of much less research than its role in the nervous, cardiovascular and immune systems, it is becoming clear that this lipid influences many of the functions, pathways and cell types that play a key role in bone maintenance and repair. Indeed, S1P is implicated in many osteogenesis-related processes including stem cell recruitment and subsequent differentiation, differentiation and survival of osteoblasts, and coupling of the latter cell type with osteoclasts. In addition, S1P's role in promoting angiogenesis is well-established. The pleiotropic effects of S1P on bone and blood vessels have significant potential therapeutic implications, as current therapeutic approaches for critical bone defects show significant limitations. Because of the complex effects of S1P on bone, the pharmacology of S1P-like agents and their physico-chemical properties, it is likely that therapeutic delivery of S1P agents will offer significant advantages compared to larger molecular weight factors. Hence, it is important to explore novel methods of utilizing S1P agents therapeutically, and improve our understanding of how S1P and its receptors modulate bone physiology and repair.
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29
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Middleton K, Al-Dujaili S, Mei X, Günther A, You L. Microfluidic co-culture platform for investigating osteocyte-osteoclast signalling during fluid shear stress mechanostimulation. J Biomech 2017; 59:35-42. [PMID: 28552413 DOI: 10.1016/j.jbiomech.2017.05.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 05/12/2017] [Accepted: 05/13/2017] [Indexed: 11/30/2022]
Abstract
Bone cells exist in a complex environment where they are constantly exposed to numerous dynamic biochemical and mechanical stimuli. These stimuli regulate bone cells that are involved in various bone disorders, such as osteoporosis. Knowledge of how these stimuli affect bone cells have been utilised to develop various treatments, such as pharmaceuticals, hormone therapy, and exercise. To investigate the role that bone loading has on these disorders in vitro, bone cell mechanotransduction studies are typically performed using parallel plate flow chambers (PPFC). However, these chambers do not allow for dynamic cellular interactions among different cell populations to be investigated. We present a microfluidic approach that exposes different cell populations, which are located at physiologically relevant distances within adjacent channels, to different levels of fluid shear stress, and promotes cell-cell communication between the different channels. We employed this microfluidic system to assess mechanically regulated osteocyte-osteoclast communication. Osteoclast precursors (RAW264.7 cells) responded to cytokine gradients (e.g., RANKL, OPG, PGE-2) developed by both mechanically stimulated (fOCY) and unstimulated (nOCY) osteocyte-like MLO-Y4 cells simultaneously. Specifically, we observed increased osteoclast precursor cell densities and osteoclast differentiation towards nOCY. We also used this system to show an increased mechanoresponse of osteocytes when in co-culture with osteoclasts. We envision broad applicability of the presented approach for microfluidic perfusion co-culture of multiple cell types in the presence of fluid flow stimulation, and as a tool to investigate osteocyte mechanotransduction, as well as bone metastasis extravasation. This system could also be applied to any multi-cell population cross-talk studies that are typically performed using PPFCs (e.g. endothelial cells, smooth muscle cells, and fibroblasts).
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Affiliation(s)
- K Middleton
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
| | - S Al-Dujaili
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
| | - X Mei
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario M5S 3G8, Canada
| | - A Günther
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada; Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario M5S 3G8, Canada
| | - L You
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada; Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario M5S 3G8, Canada.
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30
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Gorski JP, Price JL. Bone muscle crosstalk targets muscle regeneration pathway regulated by core circadian transcriptional repressors DEC1 and DEC2. BONEKEY REPORTS 2016; 5:850. [PMID: 27867498 DOI: 10.1038/bonekey.2016.80] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Revised: 09/09/2016] [Accepted: 09/26/2016] [Indexed: 12/30/2022]
Abstract
Deletion of proprotein convertase Mbtps1 in bone osteocytes leads to a significant postnatal increase in skeletal muscle size and contractile function, while causing only a 25% increase in stiffness in long bones. Concerns about leakiness in skeletal muscle were discounted since Cre recombinase expression does not account for our findings, and, Mbtps1 protein and mRNA is not deleted. Interestingly, the response of normal skeletal muscle to exercise and the regenerative response of skeletal muscle to the deletion of Mbtps1 in bone share some key regulatory features including a preference for slow twitch muscle fibers. In addition, transcriptional regulators PPAR, PGC-1α, LXR, and repressors DEC1 and DEC2 all occupy central positions within these two pathways. We hypothesize that the age-dependent muscle phenotype in Dmp1-Cre Mbtps1 cKO mice is due to bone→muscle crosstalk. Many of the myogenic genes altered in this larger and functionally improved muscle are regulated by circadian core transcriptional repressors DEC1 and DEC2, and furthermore, display a temporal coordination with Dec1 and Dec2 expression consistent with a regulatory co-dependency. These considerations lead us to propose that Dmp1-Cre Mbtps1 cKO osteocytes activate myogenesis by increased release of an activator of muscle PPAR-gamma, for example, PGE2 or sphingosine-1-P, or, by diminished release of an inhibitor of LXR, for example, long-chain polyunsaturated fatty acids. We hope that further investigation of these interacting pathways in the Dmp1-Cre Mbtps1 cKO model will lead to clinically translatable findings applicable to age-related sarcopenia and other muscle wasting syndromes.
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Affiliation(s)
- Jeffrey P Gorski
- Department of Oral and Craniofacial Sciences, School of Dentistry , Kansas City, MO, USA
| | - Jeffrey L Price
- School of Biological Sciences University of Missouri-Kansas City , Kansas City, MO, USA
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31
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Liu C, Cui X, Ackermann TM, Flamini V, Chen W, Castillo AB. Osteoblast-derived paracrine factors regulate angiogenesis in response to mechanical stimulation. Integr Biol (Camb) 2016; 8:785-94. [PMID: 27332785 PMCID: PMC8274385 DOI: 10.1039/c6ib00070c] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Angiogenesis is a process by which new blood vessels emerge from existing vessels through endothelial cell sprouting, migration, proliferation, and tubule formation. Angiogenesis during skeletal growth, homeostasis and repair is a complex and incompletely understood process. As the skeleton adapts to mechanical loading, we hypothesized that mechanical stimulation regulates "osteo-angio" crosstalk in the context of angiogenesis. We showed that conditioned media (CM) from osteoblasts exposed to fluid shear stress enhanced endothelial cell proliferation and migration, but not tubule formation, relative to CM from static cultures. Endothelial cell sprouting was studied using a dual-channel collagen gel-based microfluidic device that mimics vessel geometry. Static CM enhanced endothelial cell sprouting frequency, whereas loaded CM significantly enhanced both frequency and length. Both sprouting frequency and length were significantly enhanced in response to factors released from osteoblasts exposed to fluid shear stress in an adjacent channel. Osteoblasts released angiogenic factors, of which osteopontin, PDGF-AA, IGBP-2, MCP-1, and Pentraxin-3 were upregulated in response to mechanical loading. These data suggest that in vivo mechanical forces regulate angiogenesis in bone by modulating "osteo-angio" crosstalk through release of paracrine factors, which we term "osteokines".
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Affiliation(s)
- Chao Liu
- Department of Mechanical and Aerospace Engineering, Tandon School of Engineering, New York University, Brooklyn, NY 11201, USA. and Department of Orthopaedic Surgery, New York University School of Medicine, New York, NY 10003, USA
| | - Xin Cui
- Department of Mechanical and Aerospace Engineering, Tandon School of Engineering, New York University, Brooklyn, NY 11201, USA.
| | - Thomas M Ackermann
- Department of Mechanical and Aerospace Engineering, Tandon School of Engineering, New York University, Brooklyn, NY 11201, USA.
| | - Vittoria Flamini
- Department of Mechanical and Aerospace Engineering, Tandon School of Engineering, New York University, Brooklyn, NY 11201, USA.
| | - Weiqiang Chen
- Department of Mechanical and Aerospace Engineering, Tandon School of Engineering, New York University, Brooklyn, NY 11201, USA.
| | - Alesha B Castillo
- Department of Mechanical and Aerospace Engineering, Tandon School of Engineering, New York University, Brooklyn, NY 11201, USA. and Department of Orthopaedic Surgery, New York University School of Medicine, New York, NY 10003, USA
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32
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Jacquot J, Delion M, Gangloff S, Braux J, Velard F. Bone disease in cystic fibrosis: new pathogenic insights opening novel therapies. Osteoporos Int 2016; 27:1401-1412. [PMID: 26431978 DOI: 10.1007/s00198-015-3343-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 09/24/2015] [Indexed: 01/17/2023]
Abstract
Mutations within the gene encoding for the chloride ion channel cystic fibrosis transmembrane conductance regulator (CFTR) results in cystic fibrosis (CF), the most common lethal autosomal recessive genetic disease that causes a number of long-term health problems, as the bone disease. Osteoporosis and increased vertebral fracture risk associated with CF disease are becoming more important as the life expectancy of patients continues to improve. The etiology of low bone density is multifactorial, most probably a combination of inadequate peak bone mass during puberty and increased bone losses in adults. Body mass index, male sex, advanced pulmonary disease, malnutrition and chronic therapies are established additional risk factors for CF-related bone disease (CFBD). Consistently, recent evidence has confirmed that CFTR plays a major role in the osteoprotegerin (OPG) and COX-2 metabolite prostaglandin E2 (PGE2) production, two key regulators in the bone formation and regeneration. Several others mechanisms were also recognized from animal and cell models contributing to malfunctions of osteoblast (cell that form bone) and indirectly of bone-resorpting osteoclasts. Understanding such mechanisms is crucial for the development of therapies in CFBD. Innovative therapeutic approaches using CFTR modulators such as C18 have recently shown in vitro capacity to enhance PGE2 production and normalized the RANKL-to-OPG ratio in human osteoblasts bearing the mutation F508del-CFTR and therefore potential clinical utility in CFBD. This review focuses on the recently identified pathogenic mechanisms leading to CFBD and potential future therapies for treating CFBD.
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Affiliation(s)
- J Jacquot
- EA 4691, Biomatériaux et Inflammation en Site Osseux (BIOS), SFR CAP-Santé (FED 4231), Université Reims Champagne Ardenne, 1, Avenue du Maréchal Juin, 51095, Reims, France.
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