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Machireddy M, Oberman AG, DeBiase L, Stephens M, Li J, Littlepage LE, Niebur GL. Controlled mechanical loading affects the osteocyte transcriptome in porcine trabecular bone in situ. Bone 2024; 181:117028. [PMID: 38309412 PMCID: PMC10923013 DOI: 10.1016/j.bone.2024.117028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 01/09/2024] [Accepted: 01/29/2024] [Indexed: 02/05/2024]
Abstract
INTRODUCTION Osteocytes modulate bone adaptation in response to mechanical stimuli imparted by the deforming bone tissue in which they are encased by communicating with osteoclasts and osteoblasts as well as other osteocytes in the lacuna-canalicular network through secreted cytokines and chemokines. Understanding the transcriptional response of osteocytes to mechanical stimulation in situ could identify new targets to inhibit bone loss or enhance bone formation in the presence of diseases like osteoporosis or metastatic cancer. We compared the mechanically regulated transcriptional response of osteocytes in trabecular bone following one or three days of controlled mechanical loading. METHODS Porcine trabecular bone explants were cultured in a bioreactor for 48 h and subsequently loaded twice a day for one day or 3 days. RNA was isolated and sequenced, and the Tuxedo suite was used to identify differentially expressed genes and pathway analysis was conducted using Ingenuity Pathway Analysis (IPA). RESULTS There were about 4000 differentially expressed genes following in situ culture relative to fresh bone. One hundred six genes were differentially expressed between the loaded and non-loaded groups following one day of loading compared to 913 genes after 3 d of loading. Only 45 of these were coincident between the two time points, indicating an evolving transcriptome. Clustering and principal component analysis indicated differences between the loaded and non-loaded groups after 3 d of loading. DISCUSSION With sustained loading, there was a nine-fold increase in the number of differentially expressed genes, suggesting that osteocytes respond to loading through sequential activation of downstream genes in the same pathways. The differentially expressed genes were related to osteoarthritis, osteocyte, and chondrocyte signaling pathways. We noted that NFkB and TNF signaling are affected by early loading and this may drive downstream effects on the mechanobiological response. Moreover, these genes may regulate catabolic effects of mechanical disuse through their actions on pre-osteoclasts in the bone marrow niche.
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Affiliation(s)
- Meghana Machireddy
- Tissue Mechanics Laboratory, Bioengineering Graduate Program, University of Notre Dame, IN 46556, USA
| | - Alyssa G Oberman
- Tissue Mechanics Laboratory, Bioengineering Graduate Program, University of Notre Dame, IN 46556, USA
| | - Lucas DeBiase
- Dept. of Aerospace and Mechanical Engineering, University of Notre Dame, IN 46556, USA
| | - Melissa Stephens
- Genomics and Bioinformatics Core Facility, University of Notre Dame, IN 46556, USA
| | - Jun Li
- Dept. of Applied Mathematics, Computations, and Statistics, University of Notre Dame, IN 46556, USA
| | - Laurie E Littlepage
- Dept. of Chemistry and Biochemistry, University of Notre Dame, IN 46556, USA; Harper Cancer Research Institute, University of Notre Dame, IN 46556, USA
| | - Glen L Niebur
- Tissue Mechanics Laboratory, Bioengineering Graduate Program, University of Notre Dame, IN 46556, USA; Harper Cancer Research Institute, University of Notre Dame, IN 46556, USA; Dept. of Aerospace and Mechanical Engineering, University of Notre Dame, IN 46556, USA.
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2
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Nile M, Folwaczny M, Wichelhaus A, Baumert U, Janjic Rankovic M. Fluid flow shear stress and tissue remodeling-an orthodontic perspective: evidence synthesis and differential gene expression network analysis. Front Bioeng Biotechnol 2023; 11:1256825. [PMID: 37795174 PMCID: PMC10545883 DOI: 10.3389/fbioe.2023.1256825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 08/28/2023] [Indexed: 10/06/2023] Open
Abstract
Introduction: This study aimed to identify and analyze in vitro studies investigating the biological effect of fluid-flow shear stress (FSS) on cells found in the periodontal ligament and bone tissue. Method: We followed the PRISMA guideline for systematic reviews. A PubMed search strategy was developed, studies were selected according to predefined eligibility criteria, and the risk of bias was assessed. Relevant data related to cell source, applied FSS, and locus-specific expression were extracted. Based on this evidence synthesis and, as an original part of this work, analysis of differential gene expression using over-representation and network-analysis was performed. Five relevant publicly available gene expression datasets were analyzed using gene set enrichment analysis (GSEA). Result: A total of 6,974 articles were identified. Titles and abstracts were screened, and 218 articles were selected for full-text assessment. Finally, 120 articles were included in this study. Sample size determination and statistical analysis related to methodological quality and the ethical statement item in reporting quality were most frequently identified as high risk of bias. The analyzed studies mostly used custom-made fluid-flow apparatuses (61.7%). FSS was most frequently applied for 0.5 h, 1 h, or 2 h, whereas FSS magnitudes ranged from 6 to 20 dyn/cm2 depending on cell type and flow profile. Fluid-flow frequencies of 1 Hz in human cells and 1 and 5 Hz in mouse cells were mostly applied. FSS upregulated genes/metabolites responsible for tissue formation (AKT1, alkaline phosphatase, BGLAP, BMP2, Ca2+, COL1A1, CTNNB1, GJA1, MAPK1/MAPK3, PDPN, RUNX2, SPP1, TNFRSF11B, VEGFA, WNT3A) and inflammation (nitric oxide, PGE-2, PGI-2, PTGS1, PTGS2). Protein-protein interaction networks were constructed and analyzed using over-representation analysis and GSEA to identify shared signaling pathways. Conclusion: To our knowledge, this is the first review giving a comprehensive overview and discussion of methodological technical details regarding fluid flow application in 2D cell culture in vitro experimental conditions. Therefore, it is not only providing valuable information about cellular molecular events and their quantitative and qualitative analysis, but also confirming the reproducibility of previously published results.
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Affiliation(s)
- Mustafa Nile
- Department of Orthodontics and Dentofacial Orthopedics, LMU University Hospital, LMU Munich, Munich, Germany
| | - Matthias Folwaczny
- Department of Conservative Dentistry and Periodontology, LMU University Hospital, LMU Munich, Munich, Germany
| | - Andrea Wichelhaus
- Department of Orthodontics and Dentofacial Orthopedics, LMU University Hospital, LMU Munich, Munich, Germany
| | - Uwe Baumert
- Department of Orthodontics and Dentofacial Orthopedics, LMU University Hospital, LMU Munich, Munich, Germany
| | - Mila Janjic Rankovic
- Department of Orthodontics and Dentofacial Orthopedics, LMU University Hospital, LMU Munich, Munich, Germany
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Tetrault E, Swenson J, Aaronson B, Marcho C, Albertson RC. The transcriptional state and chromatin landscape of cichlid jaw shape variation across species and environments. Mol Ecol 2023; 32:3922-3941. [PMID: 37160741 PMCID: PMC10524807 DOI: 10.1111/mec.16975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 04/17/2023] [Accepted: 04/24/2023] [Indexed: 05/11/2023]
Abstract
Adaptive phenotypes are shaped by a combination of genetic and environmental forces, but how they interact remains poorly understood. Here, we utilize the cichlid oral jaw apparatus to better understand these gene-by-environment effects. First, we employed RNA-seq in bony and ligamentous tissues important for jaw opening to identify differentially expressed genes between species and across foraging environments. We used two Lake Malawi species adapted to different foraging habitats along the pelagic-benthic ecomorphological axis. Our foraging treatments were designed to force animals to employ either suction or biting/scraping, which broadly mimic pelagic or benthic modes of feeding. We found a large number of differentially expressed genes between species, and while we identified relatively few differences between environments, species differences were far more pronounced when they were challenged with a pelagic versus benthic foraging mode. Expression data carried the signature of genetic assimilation, and implicated cell cycle regulation in shaping the jaw across species and environments. Next, we repeated the foraging experiment and performed ATAC-seq procedures on nuclei harvested from the same tissues. Cross-referencing results from both analyses revealed subsets of genes that were both differentially expressed and differentially accessible. This reduced dataset implicated notable candidate genes including the Hedgehog effector, KIAA0586 and the ETS transcription factor, etv4, which connects environmental stress and craniofacial morphogenesis. Taken together, these data provide novel insights into the epigenetic, genetic and cellular bases of species- and environment-specific bone shapes.
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Affiliation(s)
- Emily Tetrault
- Graduate Program in Molecular and Cell Biology, University of Massachusetts, Amherst MA, 01003, U.S.A
| | - John Swenson
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst MA, 01003, U.S.A
| | - Ben Aaronson
- Biology Department, University of Massachusetts, Amherst MA, 01003, U.S.A
| | - Chelsea Marcho
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst MA, 01003, U.S.A
| | - R. Craig Albertson
- Biology Department, University of Massachusetts, Amherst MA, 01003, U.S.A
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Resveratrol protects osteocytes against oxidative stress in ovariectomized rats through AMPK/JNK1-dependent pathway leading to promotion of autophagy and inhibition of apoptosis. Cell Death Dis 2023; 9:16. [PMID: 36681672 PMCID: PMC9867734 DOI: 10.1038/s41420-023-01331-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/09/2023] [Accepted: 01/11/2023] [Indexed: 01/22/2023]
Abstract
A large number of studies in recent years indicate that osteocytes are the orchestrators of bone remodeling by regulating both osteoblast and osteoclast activities. Oxidative stress-induced osteocyte apoptosis plays critical roles in the pathological processes of postmenopausal osteoporosis. Resveratrol is a natural polyphenolic compound that ameliorates postmenopausal osteoporosis. However, whether resveratrol regulates osteocyte apoptosis via autophagy remains largely unknown. The effects of resveratrol on regulating osteocyte apoptosis and autophagy were analyzed both in vivo and in vitro. In vitro, cultured MLO-Y4 cells were exposed to H2O2 with or without resveratrol. In vivo, an ovariectomy-induced osteoporosis model was constructed in rats with or without daily intraperitoneal injection of 10 mg/kg body weight resveratrol. It was found that resveratrol attenuated H2O2-induced apoptosis through activating autophagy in cultured MLO-Y4 cells, which was mediated by the dissociation of Beclin-1/Bcl-2 complex in AMPK/JNK1-dependent pathway, ultimately regulating osteocytes function. Furthermore, it was shown that resveratrol treatment reduced osteocytes oxidative stress, inhibited osteocytes apoptosis and promoted autophagy in ovariectomized rats. Our study suggests that resveratrol protects against oxidative stress by restoring osteocytes autophagy and alleviating apoptosis via AMPK/JNK1 activation, therefore dissociating Bcl-2 from Beclin-1.
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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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6
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Xu H, Xia M, Sun L, Wang H, Zhang WB. Osteocytes Enhance Osteogenesis by Autophagy-Mediated FGF23 Secretion Under Mechanical Tension. Front Cell Dev Biol 2022; 9:782736. [PMID: 35174158 PMCID: PMC8841855 DOI: 10.3389/fcell.2021.782736] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 12/01/2021] [Indexed: 01/08/2023] Open
Abstract
Mechanical stimuli control cell behaviors that are crucial for bone tissue repair. Osteocytes sense extracellular mechanical stimuli then convert them into biochemical signals to harmonize bone remodeling. However, the mechanisms underlying this process remain unclear. Autophagy, which is an evolutionarily preserved process, that occurs at a basal level when stimulated by multiple environmental stresses. We postulated that mechanical stimulation upregulates osteocyte autophagy via AMPK-associated signaling, driving osteocyte-mediated osteogenesis. Using a murine model of orthodontic tooth movement, we show that osteocyte autophagy is triggered by mechanical tension, increasing the quantity of LC3B-positive osteocytes by 4-fold in the tension side. Both in vitro mechanical tension as well as the chemical autophagy agonist enhanced osteocyte Fibroblast growth factor 23 (FGF23) secretion, which is an osteogenenic related cytokine, by 2-and 3-fold, respectively. Conditioned media collected from tensioned osteocytes enhanced osteoblast viability. These results indicate that mechanical tension drives autophagy-mediated FGF23 secretion from osteocytes and promotes osteogenesis. Our findings highlight a potential strategy for accelerating osteogenesis in orthodontic clinical settings.
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Affiliation(s)
- Huiyue Xu
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China
| | - Meng Xia
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China
| | - Lian Sun
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China
- Department of Orthodontics, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China
| | - Hua Wang
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China
- Department of Orthodontics, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China
| | - Wei-Bing Zhang
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China
- Department of Orthodontics, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China
- Department of Stomatology, Dushu Lake Hospital Affiliated to Soochow University, Suzhou, China
- Department of Stomatology, Medical Center of Soochow University, Suzhou, China
- *Correspondence: Wei-Bing Zhang,
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Mechanical loading activates the YAP/TAZ pathway and chemokine expression in the MLO-Y4 osteocyte-like cell line. J Transl Med 2021; 101:1597-1604. [PMID: 34521992 DOI: 10.1038/s41374-021-00668-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 11/08/2022] Open
Abstract
Osteocytes are mechanosensitive cells that control bone remodeling in response to mechanical loading. To date, specific signaling pathways modulated by mechanical loading in osteocytes are not well understood. Yes associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), the main effectors of the Hippo pathway, are reported to play a role in mechanotransduction and during osteoblastogenesis. Here, we hypothesized that YAP/TAZ signaling mediates osteocyte mechanosensing to target genes of the bone remodeling process. We aimed to investigate the contribution of YAP/TAZ in modulating the gene expression in an osteocyte-like cell line MLO-Y4. We developed a 3D osteocyte compression culture model from an MLO-Y4 osteocyte cell line embedded in concentrated collagen hydrogel. 3D-mechanical loading led to the increased expression of mechanosensitive genes and a subset of chemokines, including M-csf, Cxcl1, Cxcl2, Cxcl3, Cxcl9, and Cxcl10. The transcription regulators YAP and TAZ translocated to the nucleus and upregulated their target genes and proteins. RNAseq analysis revealed that YAP/TAZ knockdown mediated the regulation of several genes including osteocyte dendrite formation. Use of YAP/TAZ knockdown partially blunted the increase in M-csf and Cxcl3 levels in response to MLO-Y4 compression. These findings demonstrate that YAP/TAZ signaling is required for osteocyte-like cell mechano-transduction, regulates the gene expression profiles and controls chemokine expression.
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Rauner M, Foessl I, Formosa MM, Kague E, Prijatelj V, Lopez NA, Banerjee B, Bergen D, Busse B, Calado Â, Douni E, Gabet Y, Giralt NG, Grinberg D, Lovsin NM, Solan XN, Ostanek B, Pavlos NJ, Rivadeneira F, Soldatovic I, van de Peppel J, van der Eerden B, van Hul W, Balcells S, Marc J, Reppe S, Søe K, Karasik D. Perspective of the GEMSTONE Consortium on Current and Future Approaches to Functional Validation for Skeletal Genetic Disease Using Cellular, Molecular and Animal-Modeling Techniques. Front Endocrinol (Lausanne) 2021; 12:731217. [PMID: 34938269 PMCID: PMC8686830 DOI: 10.3389/fendo.2021.731217] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 09/30/2021] [Indexed: 12/26/2022] Open
Abstract
The availability of large human datasets for genome-wide association studies (GWAS) and the advancement of sequencing technologies have boosted the identification of genetic variants in complex and rare diseases in the skeletal field. Yet, interpreting results from human association studies remains a challenge. To bridge the gap between genetic association and causality, a systematic functional investigation is necessary. Multiple unknowns exist for putative causal genes, including cellular localization of the molecular function. Intermediate traits ("endophenotypes"), e.g. molecular quantitative trait loci (molQTLs), are needed to identify mechanisms of underlying associations. Furthermore, index variants often reside in non-coding regions of the genome, therefore challenging for interpretation. Knowledge of non-coding variance (e.g. ncRNAs), repetitive sequences, and regulatory interactions between enhancers and their target genes is central for understanding causal genes in skeletal conditions. Animal models with deep skeletal phenotyping and cell culture models have already facilitated fine mapping of some association signals, elucidated gene mechanisms, and revealed disease-relevant biology. However, to accelerate research towards bridging the current gap between association and causality in skeletal diseases, alternative in vivo platforms need to be used and developed in parallel with the current -omics and traditional in vivo resources. Therefore, we argue that as a field we need to establish resource-sharing standards to collectively address complex research questions. These standards will promote data integration from various -omics technologies and functional dissection of human complex traits. In this mission statement, we review the current available resources and as a group propose a consensus to facilitate resource sharing using existing and future resources. Such coordination efforts will maximize the acquisition of knowledge from different approaches and thus reduce redundancy and duplication of resources. These measures will help to understand the pathogenesis of osteoporosis and other skeletal diseases towards defining new and more efficient therapeutic targets.
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Affiliation(s)
- Martina Rauner
- Department of Medicine III, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- University Hospital Carl Gustav Carus, Dresden, Germany
| | - Ines Foessl
- Department of Internal Medicine, Division of Endocrinology and Diabetology, Endocrine Lab Platform, Medical University of Graz, Graz, Austria
| | - Melissa M. Formosa
- Department of Applied Biomedical Science, Faculty of Health Sciences, University of Malta, Msida, Malta
- Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Erika Kague
- School of Physiology, Pharmacology, and Neuroscience, Faculty of Life Sciences, University of Bristol, Bristol, United Kingdom
| | - Vid Prijatelj
- Department of Oral and Maxillofacial Surgery, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
- The Generation R Study, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Nerea Alonso Lopez
- Rheumatology and Bone Disease Unit, CGEM, Institute of Genetics and Cancer (IGC), Edinburgh, United Kingdom
| | - Bodhisattwa Banerjee
- Musculoskeletal Genetics Laboratory, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Dylan Bergen
- School of Physiology, Pharmacology, and Neuroscience, Faculty of Life Sciences, University of Bristol, Bristol, United Kingdom
- Musculoskeletal Research Unit, Translational Health Sciences, Bristol Medical School, Faculty of Health Sciences, University of Bristol, Bristol, United Kingdom
| | - Björn Busse
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ângelo Calado
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Centro Académico de Medicina de Lisboa, Lisbon, Portugal
| | - Eleni Douni
- Department of Biotechnology, Agricultural University of Athens, Athens, Greece
- Institute for Bioinnovation, B.S.R.C. “Alexander Fleming”, Vari, Greece
| | - Yankel Gabet
- Department of Anatomy & Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Natalia García Giralt
- Musculoskeletal Research Group, IMIM (Hospital del Mar Medical Research Institute), Centro de Investigación Biomédica en Red en Fragilidad y Envejecimiento Saludable (CIBERFES), ISCIII, Barcelona, Spain
| | - Daniel Grinberg
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, Universitat de Barcelona, CIBERER, IBUB, IRSJD, Barcelona, Spain
| | - Nika M. Lovsin
- Department of Clinical Biochemistry, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Xavier Nogues Solan
- Musculoskeletal Research Group, IMIM (Hospital del Mar Medical Research Institute), Centro de Investigación Biomédica en Red en Fragilidad y Envejecimiento Saludable (CIBERFES), ISCIII, Barcelona, Spain
| | - Barbara Ostanek
- Department of Clinical Biochemistry, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Nathan J. Pavlos
- Bone Biology & Disease Laboratory, School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
| | | | - Ivan Soldatovic
- Institute of Medical Statistics and Informatic, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Jeroen van de Peppel
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Bram van der Eerden
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Wim van Hul
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | - Susanna Balcells
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, Universitat de Barcelona, CIBERER, IBUB, IRSJD, Barcelona, Spain
| | - Janja Marc
- Department of Clinical Biochemistry, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Sjur Reppe
- Unger-Vetlesen Institute, Lovisenberg Diaconal Hospital, Oslo, Norway
- Department of Plastic and Reconstructive Surgery, Oslo University Hospital, Oslo, Norway
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Kent Søe
- Clinical Cell Biology, Department of Pathology, Odense University Hospital, Odense, Denmark
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
- Department of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - David Karasik
- Azrieli Faculty of Medicine, Bar-Ilan University, Ramat Gan, Israel
- Marcus Research Institute, Hebrew SeniorLife, Boston, MA, United States
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Genetic variability affects the skeletal response to immobilization in founder strains of the diversity outbred mouse population. Bone Rep 2021; 15:101140. [PMID: 34761080 PMCID: PMC8566767 DOI: 10.1016/j.bonr.2021.101140] [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: 08/04/2021] [Revised: 09/28/2021] [Accepted: 10/04/2021] [Indexed: 12/13/2022] Open
Abstract
Mechanical unloading decreases bone volume and strength. In humans and mice, bone mineral density is highly heritable, and in mice the response to changes in loading varies with genetic background. Thus, genetic variability may affect the response of bone to unloading. As a first step to identify genes involved in bones' response to unloading, we evaluated the effects of unloading in eight inbred mouse strains: C57BL/6J, PWK/PhJ, WSB/EiJ, A/J, 129S1/SvImJ, NOD/ShiLtJ, NZO/HlLtJ, and CAST/EiJ. C57BL/6J and NOD/ShiLtJ mice had the greatest unloading-induced loss of diaphyseal cortical bone volume and strength. NZO/HlLtJ mice had the greatest metaphyseal trabecular bone loss, and C57BL/6J, WSB/EiJ, NOD/ShiLtJ, and CAST/EiJ mice had the greatest epiphyseal trabecular bone loss. Bone loss in the epiphyses displayed the highest heritability. With immobilization, mineral:matrix was reduced, and carbonate:phosphate and crystallinity were increased. A/J mice displayed the greatest unloading-induced loss of mineral:matrix. Changes in gene expression in response to unloading were greatest in NOD/ShiLtJ and CAST/EiJ mice. The most upregulated genes in response to unloading were associated with increased collagen synthesis and extracellular matrix formation. Our results demonstrate a strong differential response to unloading as a function of strain. Diversity outbred (DO) mice are a high-resolution mapping population derived from these eight inbred founder strains. These results suggest DO mice will be highly suited for examining the genetic basis of the skeletal response to unloading. Mouse strain affects bone's response to immobilization. Magnitude of bone loss from immobilization is heritable. Bone transcriptomic response to immobilization is influenced by genetic variation.
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10
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Matsuzaka T, Matsugaki A, Nakano T. Control of osteoblast arrangement by osteocyte mechanoresponse through prostaglandin E2 signaling under oscillatory fluid flow stimuli. Biomaterials 2021; 279:121203. [PMID: 34717197 DOI: 10.1016/j.biomaterials.2021.121203] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 10/07/2021] [Accepted: 10/20/2021] [Indexed: 01/04/2023]
Abstract
Anisotropic collagen/apatite microstructure is a prominent determinant of bone tissue functionalization; in particular, bone matrix modulates its anisotropic microstructure depending on the surrounding mechanical condition. Although mechanotransduction in bones is governed by osteocyte function, the precise mechanisms linking mechanical stimuli and anisotropic formation of collagen/apatite microstructure are poorly understood. Here we developed a novel anisotropic mechano-coculture system which enables the understanding of the biological mechanisms regulating the oriented bone matrix formation, which is constructed by aligned osteoblasts. The developed model provides bone-mimetic coculture platform that enables simultaneous control of mechanical condition and osteoblast-osteocyte communication with an anisotropic culture scaffold. The engineered coculture device helps in understanding the relationship between osteocyte mechanoresponses and osteoblast arrangement, which is a significant contributor to anisotropic organization of bone tissue. Our study showed that osteocyte responses to oscillatory flow stimuli regulated osteoblast arrangement through soluble molecular interactions. Importantly, we found that prostaglandin E2 is a novel determinant for oriented collagen/apatite organization of bone matrix, through controlling osteoblast arrangement.
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Affiliation(s)
- Tadaaki Matsuzaka
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Aira Matsugaki
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Takayoshi Nakano
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan.
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11
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Adenylyl cyclase 3 regulates osteocyte mechanotransduction and primary cilium. Biochem Biophys Res Commun 2021; 573:145-150. [PMID: 34411897 DOI: 10.1016/j.bbrc.2021.08.033] [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: 07/09/2021] [Accepted: 08/11/2021] [Indexed: 11/23/2022]
Abstract
Osteocytes are accepted as the primary mechanosensing cell in bone, but how they translate mechanical signals into biochemical signals remains unclear. Adenylyl cyclases (AC) are enzymes that catalyze the production of second messenger cyclic adenosine monophosphate (cAMP). Osteocytes display a biphasic, cAMP response to fluid shear with an initial decrease in cAMP concentrations and then an increased concentration after sustained mechanical stimulation. To date, AC6, a calcium-inhibited AC, is the primary isoform studied in bone. Since osteocytes are calcium-responsive mechanosensors, we asked if a calcium-stimulated isoform contributes to mechanotransduction. Using a transcriptomic dataset of MLO-Y4 osteocyte-like cells from the NIH Gene Expression Omnibus, we identified AC3 as the only calcium-stimulated isoform expressed. We show that inhibiting AC3 in MLO-Y4 cells results in decreased cAMP-signaling with fluid shear and increased osteogenic response to fluid flow (measured as Ptgs2 expression) of longer durations, but not shorter. AC3 likely contributes to osteocyte mechanotransduction through a signaling axis involving the primary cilium and GSK3β. We demonstrate that AC3 localizes to the primary cilium, as well as throughout the cytosol and that fluid-flow regulation of primary cilia length is altered with an AC3 knockdown. Regulation of GSK3β is downstream of the primary cilium and cAMP signaling, and with western blots we found that GSK3β inhibition by phosphorylation is increased after fluid shear in AC3 knockdown groups. Our data show that AC3 contributes to osteocyte mechanotransduction and warrants further investigation to pave the way to identifying new therapeutic targets to treat bone disease like osteoporosis.
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12
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Gardinier JD. The Diminishing Returns of Mechanical Loading and Potential Mechanisms that Desensitize Osteocytes. Curr Osteoporos Rep 2021; 19:436-443. [PMID: 34216359 PMCID: PMC9306018 DOI: 10.1007/s11914-021-00693-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/27/2021] [Indexed: 11/30/2022]
Abstract
Adaptation to mechanical loading is critical to maintaining bone mass and offers therapeutic potential to preventing age-related bone loss and osteoporosis. However, increasing the duration of loading is met with "diminishing returns" as the anabolic response quickly becomes saturated. As a result, the anabolic response to daily activities and repetitive bouts of loading is limited by the underlying mechanisms that desensitize and render bone unresponsive at the cellular level. Osteocytes are the primary cells that respond to skeletal loading and facilitate the overall anabolic response. Although many of osteocytes' signaling mechanisms activated in response to loading are considered anabolic in nature, several of them can also render osteocytes insensitive to further stimuli and thereby creating a negative feedback loop that limits osteocytes' overall response. The purpose of this review is to examine the potential mechanisms that may contribute to the loss of mechanosensitivity. In particular, we examined the inactivation/desensitization of ion channels and signaling molecules along with the potential role of endocytosis and cytoskeletal reorganization. The significance in defining the negative feedback loop is the potential to identify unique targets for enabling osteocytes to maintain their sensitivity. In doing so, we can begin to cultivate new strategies that capitalize on the anabolic nature of daily activities that repeatedly load the skeleton.
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13
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Monteiro DA, Dole NS, Campos JL, Kaya S, Schurman CA, Belair CD, Alliston T. Fluid shear stress generates a unique signaling response by activating multiple TGFβ family type I receptors in osteocytes. FASEB J 2021; 35:e21263. [PMID: 33570811 PMCID: PMC7888383 DOI: 10.1096/fj.202001998r] [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: 08/25/2020] [Revised: 11/11/2020] [Accepted: 11/25/2020] [Indexed: 12/18/2022]
Abstract
Bone is a dynamic tissue that constantly adapts to changing mechanical demands. The transforming growth factor beta (TGFβ) signaling pathway plays several important roles in maintaining skeletal homeostasis by both coupling the bone‐forming and bone‐resorbing activities of osteoblasts and osteoclasts and by playing a causal role in the anabolic response of bone to applied loads. However, the extent to which the TGFβ signaling pathway in osteocytes is directly regulated by fluid shear stress (FSS) is unknown, despite work suggesting that fluid flow along canaliculi is a dominant physical cue sensed by osteocytes following bone compression. To investigate the effects of FSS on TGFβ signaling in osteocytes, we stimulated osteocytic OCY454 cells cultured within a microfluidic platform with FSS. We find that FSS rapidly upregulates Smad2/3 phosphorylation and TGFβ target gene expression, even in the absence of added TGFβ. Indeed, relative to treatment with TGFβ, FSS induced a larger increase in levels of pSmad2/3 and Serpine1 that persisted even in the presence of a TGFβ receptor type I inhibitor. Our results show that FSS stimulation rapidly induces phosphorylation of multiple TGFβ family R‐Smads by stimulating multimerization and concurrently activating several TGFβ and BMP type I receptors, in a manner that requires the activity of the corresponding ligand. While the individual roles of the TGFβ and BMP signaling pathways in bone mechanotransduction remain unclear, these results implicate that FSS activates both pathways to generate a downstream response that differs from that achieved by either ligand alone.
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Affiliation(s)
- David A Monteiro
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, San Francisco, CA, USA
| | - Neha S Dole
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA
| | - J Luke Campos
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA
| | - Serra Kaya
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA
| | - Charles A Schurman
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, San Francisco, CA, USA
| | - Cassandra D Belair
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, USA.,Department of Urology, University of California, San Francisco, CA, USA
| | - Tamara Alliston
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, San Francisco, CA, USA.,The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, USA
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14
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Li D, Yang C, Yin C, Zhao F, Chen Z, Tian Y, Dang K, Jiang S, Zhang W, Zhang G, Qian A. LncRNA, Important Player in Bone Development and Disease. Endocr Metab Immune Disord Drug Targets 2020; 20:50-66. [PMID: 31483238 DOI: 10.2174/1871530319666190904161707] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/26/2019] [Accepted: 08/20/2019] [Indexed: 02/08/2023]
Abstract
BACKGROUND Bone is an important tissue and its normal function requires tight coordination of transcriptional networks and signaling pathways, and many of these networks/ pathways are dysregulated in pathological conditions affecting cartilage and bones. Long non-coding RNA (lncRNA) refers to a class of RNAs with a length of more than 200 nucleotides, lack of protein-coding potential, and exhibiting a wide range of biological functions. Although studies on lcnRNAs are still in their infancy, they have emerged as critical players in bone biology and bone diseases. The functions and exact mechanism of bone-related lncRNAs have not been fully classified yet. OBJECTIVE The objective of this article is to summarize the current literature on lncRNAs on the basis of their role in bone biology and diseases, focusing on their emerging molecular mechanism, pathological implications and therapeutic potential. DISCUSSION A number of lncRNAs have been identified and shown to play important roles in multiple bone cells and bone disease. The function and mechanism of bone-related lncRNA remain to be elucidated. CONCLUSION At present, majority of knowledge is limited to cellular levels and less is known on how lncRNAs could potentially control the development and homeostasis of bone. In the present review, we highlight some lncRNAs in the field of bone biology and bone disease. We also delineate some lncRNAs that might have deep impacts on understanding bone diseases and providing new therapeutic strategies to treat these diseases.
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Affiliation(s)
- Dijie Li
- Lab for Bone Metabolism, Key Lab for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,Research Center for Special Medicine and Health Systems Engineering, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,NPU-UAB Joint Laboratory for Bone Metabolism, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Chaofei Yang
- Lab for Bone Metabolism, Key Lab for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,Research Center for Special Medicine and Health Systems Engineering, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,NPU-UAB Joint Laboratory for Bone Metabolism, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Chong Yin
- Lab for Bone Metabolism, Key Lab for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,Research Center for Special Medicine and Health Systems Engineering, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,NPU-UAB Joint Laboratory for Bone Metabolism, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Fan Zhao
- Lab for Bone Metabolism, Key Lab for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,Research Center for Special Medicine and Health Systems Engineering, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,NPU-UAB Joint Laboratory for Bone Metabolism, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Zhihao Chen
- Lab for Bone Metabolism, Key Lab for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,Research Center for Special Medicine and Health Systems Engineering, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,NPU-UAB Joint Laboratory for Bone Metabolism, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Ye Tian
- Lab for Bone Metabolism, Key Lab for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,Research Center for Special Medicine and Health Systems Engineering, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,NPU-UAB Joint Laboratory for Bone Metabolism, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Kai Dang
- Lab for Bone Metabolism, Key Lab for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,Research Center for Special Medicine and Health Systems Engineering, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,NPU-UAB Joint Laboratory for Bone Metabolism, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Shanfeng Jiang
- Lab for Bone Metabolism, Key Lab for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,Research Center for Special Medicine and Health Systems Engineering, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,NPU-UAB Joint Laboratory for Bone Metabolism, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Wenjuan Zhang
- Lab for Bone Metabolism, Key Lab for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,Research Center for Special Medicine and Health Systems Engineering, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,NPU-UAB Joint Laboratory for Bone Metabolism, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Ge Zhang
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, SAR, China.,Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, SAR, China
| | - Airong Qian
- Lab for Bone Metabolism, Key Lab for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,Research Center for Special Medicine and Health Systems Engineering, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,NPU-UAB Joint Laboratory for Bone Metabolism, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
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15
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Pei S, Parthasarathy S, Parajuli A, Martinez J, Lv M, Jiang S, Wu D, Wei S, Lu XL, Farach-Carson MC, Kirn-Safran CB, Wang L. Perlecan/Hspg2 deficiency impairs bone's calcium signaling and associated transcriptome in response to mechanical loading. Bone 2020; 131:115078. [PMID: 31715337 PMCID: PMC6945981 DOI: 10.1016/j.bone.2019.115078] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 09/24/2019] [Accepted: 09/24/2019] [Indexed: 10/25/2022]
Abstract
Perlecan, a heparan sulfate proteoglycan, acts as a mechanical sensor for bone to detect external loading. Deficiency of perlecan increases the risk of osteoporosis in patients with Schwartz-Jampel Syndrome (SJS) and attenuates loading-induced bone formation in perlecan deficient mice (Hypo). Considering that intracellular calcium [Ca2+]i is an ubiquitous messenger controlling numerous cellular processes including mechanotransduction, we hypothesized that perlecan deficiency impairs bone's calcium signaling in response to loading. To test this, we performed real-time [Ca2+]i imaging on in situ osteocytes of adult murine tibiae under cyclic loading (8N). Relative to wild type (WT), Hypo osteocytes showed decreases in the overall [Ca2+]i response rate (-58%), calcium peaks (-33%), cells with multiple peaks (-53%), peak magnitude (-6.8%), and recovery speed to baseline (-23%). RNA sequencing and pathway analysis of tibiae from mice subjected to one or seven days of unilateral loading demonstrated that perlecan deficiency significantly suppressed the calcium signaling, ECM-receptor interaction, and focal adhesion pathways following repetitive loading. Defects in the endoplasmic reticulum (ER) calcium cycling regulators such as Ryr1/ryanodine receptors and Atp2a1/Serca1 calcium pumps were identified in Hypo bones. Taken together, impaired calcium signaling may contribute to bone's reduced anabolic response to loading, underlying the osteoporosis risk for the SJS patients.
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Affiliation(s)
- Shaopeng Pei
- Center for Biomechanical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
| | | | - Ashutosh Parajuli
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19716, United States
| | - Jerahme Martinez
- Center for Biomechanical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
| | - Mengxi Lv
- Center for Biomechanical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
| | - Sida Jiang
- Center for Biomechanical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
| | - Danielle Wu
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, University of Texas Health Science Center, Houston, TX 77054, United States
| | - Shuo Wei
- Center for Biomechanical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
| | - X Lucas Lu
- Center for Biomechanical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
| | - Mary C Farach-Carson
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, University of Texas Health Science Center, Houston, TX 77054, United States
| | - Catherine B Kirn-Safran
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States; Department of Biology, Widener University, Chester, PA 19013, United States
| | - Liyun Wang
- Center for Biomechanical Engineering Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States; Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States; Department of Biomedical Engineering, University of Delaware, Newark, DE 19716, United States.
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16
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Abstract
PURPOSE OF REVIEW The goal of this paper is to review state-of-the-art transcriptome profiling methods and their recent applications in the field of skeletal biology. RECENT FINDINGS Next-generation sequencing of mRNA (RNA-seq) methods have been established and routinely used in skeletal biology research. RNA-seq has led to the identification of novel genes and transcription factors involved in skeletal development and disease, through its application in small and large animal models, as well as human tissue and cells. With the availability of advanced techniques such as single-cell RNA-seq, novel cell types in skeletal tissues are being identified. As the sequencing technologies are rapidly evolving, the exciting discoveries supported by transcriptomics will continue to emerge and improve our understanding of the biology of the skeleton.
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Affiliation(s)
- Ugur Ayturk
- Musculoskeletal Integrity Program, Hospital for Special Surgery, 515 East 71st St. Suite 403, New York, NY, 10021, USA.
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17
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Meng F, Murray GF, Kurgan L, Donahue HJ. Functional and structural characterization of osteocytic MLO-Y4 cell proteins encoded by genes differentially expressed in response to mechanical signals in vitro. Sci Rep 2018; 8:6716. [PMID: 29712973 PMCID: PMC5928037 DOI: 10.1038/s41598-018-25113-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/09/2018] [Indexed: 12/29/2022] Open
Abstract
The anabolic response of bone to mechanical load is partially the result of osteocyte response to fluid flow-induced shear stress. Understanding signaling pathways activated in osteocytes exposed to fluid flow could identify novel signaling pathways involved in the response of bone to mechanical load. Bioinformatics allows for a unique perspective and provides key first steps in understanding these signaling pathways. We examined proteins encoded by genes differentially expressed in response to fluid flow in murine osteocytic MLO-Y4 cells. We considered structural and functional characteristics including putative intrinsic disorder, evolutionary conservation, interconnectedness in protein-protein interaction networks, and cellular localization. Our analysis suggests that proteins encoded by fluid flow activated genes have lower than expected conservation, are depleted in intrinsic disorder, maintain typical levels of connectivity for the murine proteome, and are found in the cytoplasm and extracellular space. Pathway analyses reveal that these proteins are associated with cellular response to stress, chemokine and cytokine activity, enzyme binding, and osteoclast differentiation. The lower than expected disorder of proteins encoded by flow activated genes suggests they are relatively specialized.
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Affiliation(s)
- Fanchi Meng
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada
| | - Graeme F Murray
- Bone Engineering, Science and Technology (BEST) Laboratory, Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Lukasz Kurgan
- Department of Computer Science, Virginia Commonwealth University, Richmond, Virginia, United States of America.
| | - Henry J Donahue
- Bone Engineering, Science and Technology (BEST) Laboratory, Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States of America.
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18
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Amirhosseini M, Andersson G, Aspenberg P, Fahlgren A. Mechanical instability and titanium particles induce similar transcriptomic changes in a rat model for periprosthetic osteolysis and aseptic loosening. Bone Rep 2017; 7:17-25. [PMID: 28795083 PMCID: PMC5544474 DOI: 10.1016/j.bonr.2017.07.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 07/24/2017] [Accepted: 07/26/2017] [Indexed: 01/30/2023] Open
Abstract
Wear debris particles released from prosthetic bearing surfaces and mechanical instability of implants are two main causes of periprosthetic osteolysis. While particle-induced loosening has been studied extensively, mechanisms through which mechanical factors lead to implant loosening have been less investigated. This study compares the transcriptional profiles associated with osteolysis in a rat model for aseptic loosening, induced by either mechanical instability or titanium particles. Rats were exposed to mechanical instability or titanium particles. After 15 min, 3, 48 or 120 h from start of the stimulation, gene expression changes in periprosthetic bone tissue was determined by microarray analysis. Microarray data were analyzed by PANTHER Gene List Analysis tool and Ingenuity Pathway Analysis (IPA). Both types of osteolytic stimulation led to gene regulation in comparison to unstimulated controls after 3, 48 or 120 h. However, when mechanical instability was compared to titanium particles, no gene showed a statistically significant difference (fold change ≥ ± 1.5 and adjusted p-value ≤ 0.05) at any time point. There was a remarkable similarity in numbers and functional classification of regulated genes. Pathway analysis showed several inflammatory pathways activated by both stimuli, including Acute Phase Response signaling, IL-6 signaling and Oncostatin M signaling. Quantitative PCR confirmed the changes in expression of key genes involved in osteolysis observed by global transcriptomics. Inflammatory mediators including interleukin (IL)-6, IL-1β, chemokine (C-C motif) ligand (CCL)2, prostaglandin-endoperoxide synthase (Ptgs)2 and leukemia inhibitory factor (LIF) showed strong upregulation, as assessed by both microarray and qPCR. By investigating genome-wide expression changes we show that, despite the different nature of mechanical implant instability and titanium particles, osteolysis seems to be induced through similar biological and signaling pathways in this rat model for aseptic loosening. Pathways associated to the innate inflammatory response appear to be a major driver for osteolysis. Our findings implicate early restriction of inflammation to be critical to prevent or mitigate osteolysis and aseptic loosening of orthopedic implants.
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Affiliation(s)
- Mehdi Amirhosseini
- Division of Cell Biology, Department of Clinical and Experimental Medicine, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden
- Corresponding author.
| | - Göran Andersson
- Division of Pathology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden
| | - Per Aspenberg
- Orthopedics, Department of Clinical and Experimental Medicine, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden
| | - Anna Fahlgren
- Division of Cell Biology, Department of Clinical and Experimental Medicine, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden
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19
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Scheuren A, Wehrle E, Flohr F, Müller R. Bone mechanobiology in mice: toward single-cell in vivo mechanomics. Biomech Model Mechanobiol 2017; 16:2017-2034. [PMID: 28735414 DOI: 10.1007/s10237-017-0935-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Accepted: 07/11/2017] [Indexed: 01/27/2023]
Abstract
Mechanically driven bone (re)modeling is a multiscale process mediated through complex interactions between multiple cell types and their microenvironments. However, the underlying mechanisms of how cells respond to mechanical signals are still unclear and are at the focus of the field of bone mechanobiology. Traditionally, this complex process has been addressed by reducing the system to single scales and cell types. It is only recently that more integrative approaches have been established to study bone mechanobiology across multiple scales in which mechanical load at the organ level is related to molecular responses at the cellular level. The availability of mouse loading models and imaging techniques with improved spatial and temporal resolution has made it possible to track dynamic bone (re)modeling at the tissue and cellular level in vivo. Coupled with advanced computational models, the (re)modeling activities at the tissue scale can be associated with the mechanical microenvironment. However, methods are lacking to link the molecular responses of different cell types to their local mechanical microenvironment and bone (re)modeling activities occurring at the tissue scale. With recent improvements in "omics" technologies and single-cell molecular biology, it is now possible to sequence the complete genome and transcriptome of single cells. These technologies offer unique opportunities to comprehensively investigate the cellular transcriptional profiles within their specific microenvironment. By combining single-cell "omics" technologies with well-established tissue-scale models of bone mechanobiology, we propose a mechanomics approach to locally analyze the transcriptome of single cells with respect to their local 3D mechanical in vivo environment.
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Affiliation(s)
- Ariane Scheuren
- Institute for Biomechanics, ETH Zurich, Leopold-Ruzicka-Weg 4, 8093, Zurich, Switzerland
| | - Esther Wehrle
- Institute for Biomechanics, ETH Zurich, Leopold-Ruzicka-Weg 4, 8093, Zurich, Switzerland
| | - Felicitas Flohr
- Institute for Biomechanics, ETH Zurich, Leopold-Ruzicka-Weg 4, 8093, Zurich, Switzerland
| | - Ralph Müller
- Institute for Biomechanics, ETH Zurich, Leopold-Ruzicka-Weg 4, 8093, Zurich, Switzerland.
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20
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Mao R, Yang R, Chen X, Harhaj EW, Wang X, Fan Y. Regnase-1, a rapid response ribonuclease regulating inflammation and stress responses. Cell Mol Immunol 2017; 14:412-422. [PMID: 28194024 PMCID: PMC5423090 DOI: 10.1038/cmi.2016.70] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 11/17/2016] [Accepted: 11/17/2016] [Indexed: 02/07/2023] Open
Abstract
RNA-binding proteins (RBPs) are central players in post-transcriptional regulation and immune homeostasis. The ribonuclease and RBP Regnase-1 exerts critical roles in both immune cells and non-immune cells. Its expression is rapidly induced under diverse conditions including microbial infections, treatment with inflammatory cytokines and chemical or mechanical stimulation. Regnase-1 activation is transient and is subject to negative feedback mechanisms including proteasome-mediated degradation or mucosa-associated lymphoid tissue 1 (MALT1) mediated cleavage. The major function of Regnase-1 is promoting mRNA decay via its ribonuclease activity by specifically targeting a subset of genes in different cell types. In monocytes, Regnase-1 downregulates IL-6 and IL-12B mRNAs, thus mitigating inflammation, whereas in T cells, it restricts T-cell activation by targeting c-Rel, Ox40 and Il-2 transcripts. In cancer cells, Regnase-1 promotes apoptosis by inhibiting anti-apoptotic genes including Bcl2L1, Bcl2A1, RelB and Bcl3. Together with up-frameshift protein-1 (UPF1), Regnase-1 specifically cleaves mRNAs that are active during translation by recognizing a stem-loop (SL) structure within the 3'UTRs of these genes in endoplasmic reticulum-bound ribosomes. Through this mechanism, Regnase-1 rapidly shapes mRNA profiles and associated protein expression, restricts inflammation and maintains immune homeostasis. Dysregulation of Regnase-1 has been described in a multitude of pathological states including autoimmune diseases, cancer and cardiovascular diseases. Here, we provide a comprehensive update on the function, regulation and molecular mechanisms of Regnase-1, and we propose that Regnase-1 may function as a master rapid response gene for cellular adaption triggered by microenvironmental changes.
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Affiliation(s)
- Renfang Mao
- Basic Medical Research Center, School of Medicine, Nantong University, Nantong, Jiangsu 226001, People's Republic of China
| | - Riyun Yang
- Basic Medical Research Center, School of Medicine, Nantong University, Nantong, Jiangsu 226001, People's Republic of China
| | - Xia Chen
- Basic Medical Research Center, School of Medicine, Nantong University, Nantong, Jiangsu 226001, People's Republic of China
| | - Edward W Harhaj
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
| | - Xiaoying Wang
- Department of Immunology, School of Medicine, Nantong University, Nantong, Jiangsu 226001, People's Republic of China
| | - Yihui Fan
- Basic Medical Research Center, School of Medicine, Nantong University, Nantong, Jiangsu 226001, People's Republic of China
- Department of Immunology, School of Medicine, Nantong University, Nantong, Jiangsu 226001, People's Republic of China
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21
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Iwaniec UT, Turner RT. Influence of body weight on bone mass, architecture and turnover. J Endocrinol 2016; 230:R115-30. [PMID: 27352896 PMCID: PMC4980254 DOI: 10.1530/joe-16-0089] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 06/27/2016] [Indexed: 12/11/2022]
Abstract
Weight-dependent loading of the skeleton plays an important role in establishing and maintaining bone mass and strength. This review focuses on mechanical signaling induced by body weight as an essential mechanism for maintaining bone health. In addition, the skeletal effects of deviation from normal weight are discussed. The magnitude of mechanical strain experienced by bone during normal activities is remarkably similar among vertebrates, regardless of size, supporting the existence of a conserved regulatory mechanism, or mechanostat, that senses mechanical strain. The mechanostat functions as an adaptive mechanism to optimize bone mass and architecture based on prevailing mechanical strain. Changes in weight, due to altered mass, weightlessness (spaceflight), and hypergravity (modeled by centrifugation), induce an adaptive skeletal response. However, the precise mechanisms governing the skeletal response are incompletely understood. Furthermore, establishing whether the adaptive response maintains the mechanical competence of the skeleton has proven difficult, necessitating the development of surrogate measures of bone quality. The mechanostat is influenced by regulatory inputs to facilitate non-mechanical functions of the skeleton, such as mineral homeostasis, as well as hormones and energy/nutrient availability that support bone metabolism. Although the skeleton is very capable of adapting to changes in weight, the mechanostat has limits. At the limits, extreme deviations from normal weight and body composition are associated with impaired optimization of bone strength to prevailing body size.
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Affiliation(s)
- Urszula T Iwaniec
- Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA Center for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USA
| | - Russell T Turner
- Skeletal Biology LaboratorySchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA Center for Healthy Aging ResearchOregon State University, Corvallis, Oregon, USA
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