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Centrone M, Saltarella I, D'Agostino M, Ranieri M, Venneri M, Di Mise A, Simone L, Pisani F, Valenti G, Frassanito MA, Tamma G. RhoB plays a central role in hyperosmolarity-induced cell shrinkage in renal cells. J Cell Physiol 2024. [PMID: 38946197 DOI: 10.1002/jcp.31343] [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: 11/28/2023] [Revised: 06/06/2024] [Accepted: 06/11/2024] [Indexed: 07/02/2024]
Abstract
The small Rho GTP-binding proteins are important cell morphology, function, and apoptosis regulators. Unlike other Rho proteins, RhoB can be subjected to either geranylgeranylation (RhoB-GG) or farnesylation (RhoB-F), making that the only target of the farnesyltransferase inhibitor (FTI). Fluorescence resonance energy transfer experiments revealed that RhoB is activated by hyperosmolarity. By contrast, hyposmolarity did not affect RhoB activity. Interestingly, treatment with farnesyltransferase inhibitor-277 (FTI-277) decreased the cell size. To evaluate whether RhoB plays a role in volume reduction, renal collecting duct MCD4 cells and Human Kidney, HK-2 were transiently transfected with RhoB-wildtype-Enhance Green Fluorescence Protein (RhoB-wt-EGFP) and RhoB-CLLL-EGFP which cannot undergo farnesylation. A calcein-based fluorescent assay revealed that hyperosmolarity caused a significant reduction of cell volume in mock and RhoB-wt-EGFP-expressing cells. By contrast, cells treated with FTI-277 or expressing the RhoB-CLLL-EGFP mutant did not properly respond to hyperosmolarity with respect to mock and RhoB-wt-EGFP expressing cells. These findings were further confirmed by 3D-LSCM showing that RhoB-CLLL-EGFP cells displayed a significant reduction in cell size compared to cells expressing RhoB-wt-EGFP. Moreover, flow cytometry analysis revealed that RhoB-CLLL-EGFP expressing cells as well as FTI-277-treated cells showed a significant increase in cell apoptosis. Together, these data suggested that: (i) RhoB is sensitive to hyperosmolarity and not to hyposmolarity; (ii) inhibition of RhoB farnesylation associates with an increase in cell apoptosis, likely suggesting that RhoB might be a paramount player controlling apoptosis by interfering with responses to cell volume change.
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Affiliation(s)
- Mariangela Centrone
- Department of Biosciences Biotechnologies and Environment, University of Bari Aldo Moro, Bari, Italy
| | - Ilaria Saltarella
- Department of Precision and Regenerative Medicine and Ionian Area, Section of Pharmacology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Mariagrazia D'Agostino
- Department of Biosciences Biotechnologies and Environment, University of Bari Aldo Moro, Bari, Italy
| | - Marianna Ranieri
- Department of Biosciences Biotechnologies and Environment, University of Bari Aldo Moro, Bari, Italy
| | - Maria Venneri
- Istituti Clinici Scientifici Maugeri SPA SB IRCCS, Bari, Italy
| | - Annarita Di Mise
- Department of Biosciences Biotechnologies and Environment, University of Bari Aldo Moro, Bari, Italy
| | - Laura Simone
- Fondazione IRCCS Casa Sollievo della Sofferenza, Cancer Stem Cells Unit, San Giovanni Rotondo, Italy
| | - Francesco Pisani
- Department of Biosciences Biotechnologies and Environment, University of Bari Aldo Moro, Bari, Italy
| | - Giovanna Valenti
- Department of Biosciences Biotechnologies and Environment, University of Bari Aldo Moro, Bari, Italy
| | - Maria A Frassanito
- Department of Precision and Regenerative Medicine and Ionian Area, Section of Clinical Pathology, University of Bari Aldo Moro, Bari, Italy
| | - Grazia Tamma
- Department of Biosciences Biotechnologies and Environment, University of Bari Aldo Moro, Bari, Italy
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Jia Y, Le H, Wang X, Zhang J, Liu Y, Ding J, Zheng C, Chang F. Double-edged role of mechanical stimuli and underlying mechanisms in cartilage tissue engineering. Front Bioeng Biotechnol 2023; 11:1271762. [PMID: 38053849 PMCID: PMC10694366 DOI: 10.3389/fbioe.2023.1271762] [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: 08/02/2023] [Accepted: 10/11/2023] [Indexed: 12/07/2023] Open
Abstract
Mechanical stimuli regulate the chondrogenic differentiation of mesenchymal stem cells and the homeostasis of chondrocytes, thus affecting implant success in cartilage tissue engineering. The mechanical microenvironment plays fundamental roles in the maturation and maintenance of natural articular cartilage, and the progression of osteoarthritis Hence, cartilage tissue engineering attempts to mimic this environment in vivo to obtain implants that enable a superior regeneration process. However, the specific type of mechanical loading, its optimal regime, and the underlying molecular mechanisms are still under investigation. First, this review delineates the composition and structure of articular cartilage, indicating that the morphology of chondrocytes and components of the extracellular matrix differ from each other to resist forces in three top-to-bottom overlapping zones. Moreover, results from research experiments and clinical trials focusing on the effect of compression, fluid shear stress, hydrostatic pressure, and osmotic pressure are presented and critically evaluated. As a key direction, the latest advances in mechanisms involved in the transduction of external mechanical signals into biological signals are discussed. These mechanical signals are sensed by receptors in the cell membrane, such as primary cilia, integrins, and ion channels, which next activate downstream pathways. Finally, biomaterials with various modifications to mimic the mechanical properties of natural cartilage and the self-designed bioreactors for experiment in vitro are outlined. An improved understanding of biomechanically driven cartilage tissue engineering and the underlying mechanisms is expected to lead to efficient articular cartilage repair for cartilage degeneration and disease.
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Affiliation(s)
- Yao Jia
- Department of Orthopedics, The Second Hospital of Jilin University, Jilin, China
- The Second Bethune Clinical Medical College of Jilin University, Jilin, China
| | - Hanxiang Le
- Department of Orthopedics, The Second Hospital of Jilin University, Jilin, China
- The Fourth Treatment Area of Trauma Hip Joint Surgery Department, Tianjin Hospital, Tianjin, China
| | - Xianggang Wang
- Department of Orthopedics, The Second Hospital of Jilin University, Jilin, China
| | - Jiaxin Zhang
- Department of Orthopedics, The Second Hospital of Jilin University, Jilin, China
| | - Yan Liu
- The Second Bethune Clinical Medical College of Jilin University, Jilin, China
| | - Jiacheng Ding
- The Second Bethune Clinical Medical College of Jilin University, Jilin, China
| | - Changjun Zheng
- Department of Orthopedics, The Second Hospital of Jilin University, Jilin, China
| | - Fei Chang
- Department of Orthopedics, The Second Hospital of Jilin University, Jilin, China
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Vágó J, Takács R, Kovács P, Hajdú T, van der Veen DR, Matta C. Combining biomechanical stimulation and chronobiology: a novel approach for augmented chondrogenesis? Front Bioeng Biotechnol 2023; 11:1232465. [PMID: 37456723 PMCID: PMC10349586 DOI: 10.3389/fbioe.2023.1232465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 06/20/2023] [Indexed: 07/18/2023] Open
Abstract
The unique structure and composition of articular cartilage is critical for its physiological function. However, this architecture may get disrupted by degeneration or trauma. Due to the low intrinsic regeneration properties of the tissue, the healing response is generally poor. Low-grade inflammation in patients with osteoarthritis advances cartilage degradation, resulting in pain, immobility, and reduced quality of life. Generating neocartilage using advanced tissue engineering approaches may address these limitations. The biocompatible microenvironment that is suitable for cartilage regeneration may not only rely on cells and scaffolds, but also on the spatial and temporal features of biomechanics. Cell-autonomous biological clocks that generate circadian rhythms in chondrocytes are generally accepted to be indispensable for normal cartilage homeostasis. While the molecular details of the circadian clockwork are increasingly well understood at the cellular level, the mechanisms that enable clock entrainment by biomechanical signals, which are highly relevant in cartilage, are still largely unknown. This narrative review outlines the role of the biomechanical microenvironment to advance cartilage tissue engineering via entraining the molecular circadian clockwork, and highlights how application of this concept may enhance the development and successful translation of biomechanically relevant tissue engineering interventions.
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Affiliation(s)
- Judit Vágó
- Department of Anatomy, Faculty of Medicine, Histology and Embryology, University of Debrecen, Debrecen, Hungary
| | - Roland Takács
- Department of Anatomy, Faculty of Medicine, Histology and Embryology, University of Debrecen, Debrecen, Hungary
| | - Patrik Kovács
- Department of Anatomy, Faculty of Medicine, Histology and Embryology, University of Debrecen, Debrecen, Hungary
| | - Tibor Hajdú
- Department of Anatomy, Faculty of Medicine, Histology and Embryology, University of Debrecen, Debrecen, Hungary
| | - Daan R. van der Veen
- Chronobiology Section, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Csaba Matta
- Department of Anatomy, Faculty of Medicine, Histology and Embryology, University of Debrecen, Debrecen, Hungary
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Stam LB, Clark AL. Chondrocyte primary cilia lengthening and shortening in response to mediators of osteoarthritis; a role for integrin α1β1 and focal adhesions. OSTEOARTHRITIS AND CARTILAGE OPEN 2023; 5:100357. [PMID: 37008821 PMCID: PMC10063384 DOI: 10.1016/j.ocarto.2023.100357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 03/14/2023] [Indexed: 03/29/2023] Open
Abstract
Objective Integrin α1β1 protects against osteoarthritis when it is upregulated in the early stages of disease, however, the mechanism behind this is currently unknown. Hypo-osmotic stress, interleukin-1 (IL-1) and transforming growth factor β (TGFβ) influence chondrocyte signaling and are important mediators of osteoarthritis. Evidence for primary cilia as a signaling hub for these factors and the involvement of the F-actin cytoskeleton in this response is growing. The purpose of this study was to investigate the role of integrin α1β1 in the response of primary cilia and the F-actin cytoskeleton to these osteoarthritic mediators. Design Primary cilia length and the number of F-actin peaks were measured in ex vivo wild type and itga1-null chondrocytes in response to hypo-osmotic stress, IL-1, and TGFβ alone or in combination, and with or without focal adhesion kinase inhibitor. Results We show that integrin α1β1 and focal adhesions are necessary for cilial lengthening and increases in F-actin peaks with hypo-osmotic stress and IL-1, but are not required for cilial shortening with TGFβ. Furthermore, we established that the chondrocyte primary cilium has a resting length of 2.4 μm, a minimum length of 2.1 μm corresponding to the thickness of the pericellular matrix, and a maximum length of 3.0 μm. Conclusions While integrin α1β1 is not necessary for the formation of chondrocyte primary cilia and cilial shortening in response to TGFβ, it is necessary for the mediation of cilial lengthening and the formation of F-actin peaks in response to hypo-osmotic stress and IL-1.
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Mechanotransduction pathways in articular chondrocytes and the emerging role of estrogen receptor-α. Bone Res 2023; 11:13. [PMID: 36869045 PMCID: PMC9984452 DOI: 10.1038/s41413-023-00248-x] [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: 09/06/2022] [Revised: 12/05/2022] [Accepted: 01/06/2023] [Indexed: 03/05/2023] Open
Abstract
In the synovial joint, mechanical force creates an important signal that influences chondrocyte behavior. The conversion of mechanical signals into biochemical cues relies on different elements in mechanotransduction pathways and culminates in changes in chondrocyte phenotype and extracellular matrix composition/structure. Recently, several mechanosensors, the first responders to mechanical force, have been discovered. However, we still have limited knowledge about the downstream molecules that enact alterations in the gene expression profile during mechanotransduction signaling. Recently, estrogen receptor α (ERα) has been shown to modulate the chondrocyte response to mechanical loading through a ligand-independent mechanism, in line with previous research showing that ERα exerts important mechanotransduction effects on other cell types, such as osteoblasts. In consideration of these recent discoveries, the goal of this review is to position ERα into the mechanotransduction pathways known to date. Specifically, we first summarize our most recent understanding of the mechanotransduction pathways in chondrocytes on the basis of three categories of actors, namely mechanosensors, mechanotransducers, and mechanoimpactors. Then, the specific roles played by ERα in mediating the chondrocyte response to mechanical loading are discussed, and the potential interactions of ERα with other molecules in mechanotransduction pathways are explored. Finally, we propose several future research directions that may advance our understanding of the roles played by ERα in mediating biomechanical cues under physiological and pathological conditions.
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Segarra-Queralt M, Piella G, Noailly J. Network-based modelling of mechano-inflammatory chondrocyte regulation in early osteoarthritis. Front Bioeng Biotechnol 2023; 11:1006066. [PMID: 36815875 PMCID: PMC9936426 DOI: 10.3389/fbioe.2023.1006066] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 01/16/2023] [Indexed: 02/05/2023] Open
Abstract
Osteoarthritis (OA) is a debilitating joint disease characterized by articular cartilage degradation, inflammation and pain. An extensive range of in vivo and in vitro studies evidences that mechanical loads induce changes in chondrocyte gene expression, through a process known as mechanotransduction. It involves cascades of complex molecular interactions that convert physical signals into cellular response(s) that favor either chondroprotection or cartilage destruction. Systematic representations of those interactions can positively inform early strategies for OA management, and dynamic modelling allows semi-quantitative representations of the steady states of complex biological system according to imposed initial conditions. Yet, mechanotransduction is rarely integrated. Hence, a novel mechano-sensitive network-based model is proposed, in the form of a continuous dynamical system: an interactome of a set of 118 nodes, i.e., mechano-sensitive cellular receptors, second messengers, transcription factors and proteins, related among each other through a specific topology of 358 directed edges is developed. Results show that under physio-osmotic initial conditions, an anabolic state is reached, whereas initial perturbations caused by pro-inflammatory and injurious mechanical loads leads to a catabolic profile of node expression. More specifically, healthy chondrocyte markers (Sox9 and CITED2) are fully expressed under physio-osmotic conditions, and reduced under inflammation, or injurious loadings. In contrast, NF-κB and Runx2, characteristic of an osteoarthritic chondrocyte, become activated under inflammation or excessive loading regimes. A literature-based evaluation shows that the model can replicate 94% of the experiments tested. Sensitivity analysis based on a factorial design of a treatment shows that inflammation has the strongest influence on chondrocyte metabolism, along with a significant deleterious effect of static compressive loads. At the same time, anti-inflammatory therapies appear as the most promising ones, though the restoration of structural protein production seems to remain a major challenge even in beneficial mechanical environments. The newly developed mechano-sensitive network model for chondrocyte activity reveals a unique potential to reflect load-induced chondroprotection or articular cartilage degradation in different mechano-chemical-environments.
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Broeders M, van Rooij J, Oussoren E, van Gestel T, Smith C, Kimber S, Verdijk R, Wagenmakers M, van den Hout J, van der Ploeg A, Narcisi R, Pijnappel W. Modeling cartilage pathology in mucopolysaccharidosis VI using iPSCs reveals early dysregulation of chondrogenic and metabolic gene expression. Front Bioeng Biotechnol 2022; 10:949063. [PMID: 36561048 PMCID: PMC9763729 DOI: 10.3389/fbioe.2022.949063] [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: 05/20/2022] [Accepted: 11/09/2022] [Indexed: 12/12/2022] Open
Abstract
Mucopolysaccharidosis type VI (MPS VI) is a metabolic disorder caused by disease-associated variants in the Arylsulfatase B (ARSB) gene, resulting in ARSB enzyme deficiency, lysosomal glycosaminoglycan accumulation, and cartilage and bone pathology. The molecular response to MPS VI that results in cartilage pathology in human patients is largely unknown. Here, we generated a disease model to study the early stages of cartilage pathology in MPS VI. We generated iPSCs from four patients and isogenic controls by inserting the ARSB cDNA in the AAVS1 safe harbor locus using CRISPR/Cas9. Using an optimized chondrogenic differentiation protocol, we found Periodic acid-Schiff positive inclusions in hiPSC-derived chondrogenic cells with MPS VI. Genome-wide mRNA expression analysis showed that hiPSC-derived chondrogenic cells with MPS VI downregulated expression of genes involved in TGF-β/BMP signalling, and upregulated expression of inhibitors of the Wnt/β-catenin signalling pathway. Expression of genes involved in apoptosis and growth was upregulated, while expression of genes involved in glycosaminoglycan metabolism was dysregulated in hiPSC-derived chondrogenic cells with MPS VI. These results suggest that human ARSB deficiency in MPS VI causes changes in the transcriptional program underlying the early stages of chondrogenic differentiation and metabolism.
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Affiliation(s)
- M. Broeders
- Department of Pediatrics, Erasmus MC University Medical Center, Rotterdam, Netherlands
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, Netherlands
- Center for Lysosomal and Metabolic Diseases, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - Jgj van Rooij
- Department of Internal Medicine, Erasmus MC Medical Center, Rotterdam, Netherlands
| | - E. Oussoren
- Department of Pediatrics, Erasmus MC University Medical Center, Rotterdam, Netherlands
- Center for Lysosomal and Metabolic Diseases, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - Tjm van Gestel
- Department of Pediatrics, Erasmus MC University Medical Center, Rotterdam, Netherlands
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, Netherlands
- Center for Lysosomal and Metabolic Diseases, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - Ca Smith
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Sj Kimber
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Rm Verdijk
- Department of Pathology, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - Maem Wagenmakers
- Center for Lysosomal and Metabolic Diseases, Erasmus MC University Medical Center, Rotterdam, Netherlands
- Department of Internal Medicine, Erasmus MC Medical Center, Rotterdam, Netherlands
| | - Jmp van den Hout
- Department of Pediatrics, Erasmus MC University Medical Center, Rotterdam, Netherlands
- Center for Lysosomal and Metabolic Diseases, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - At van der Ploeg
- Department of Pediatrics, Erasmus MC University Medical Center, Rotterdam, Netherlands
- Center for Lysosomal and Metabolic Diseases, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - R. Narcisi
- Department of Orthopaedics and Sports Medicine, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - Wwmp Pijnappel
- Department of Pediatrics, Erasmus MC University Medical Center, Rotterdam, Netherlands
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, Netherlands
- Center for Lysosomal and Metabolic Diseases, Erasmus MC University Medical Center, Rotterdam, Netherlands
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Li W, Zhou Y, Han L, Wang L, Lucas Lu X. Calcium signaling of primary chondrocytes and ATDC5 chondrogenic cells under osmotic stress and mechanical stimulation. J Biomech 2022; 145:111388. [PMID: 36413831 PMCID: PMC10472919 DOI: 10.1016/j.jbiomech.2022.111388] [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: 08/18/2022] [Accepted: 11/11/2022] [Indexed: 11/18/2022]
Abstract
Calcium signaling plays an essential role in chondrocyte mechanotransduction. Guilak and colleagues have revealed the roles of TRPV4 and Piezo channels in chondrocyte calcium signaling and metabolism. This study compared the calcium responses of primary chondrocytes and ATDC5 cells induced by two different stimuli: osmotic stress and intense mechanical stimulus. Roles of three essential calcium signaling pathways, including extracellular calcium source, intracellular ER calcium store and mechanical-sensitive ion channels, were also investigated and compared between cells. Primary chondrocytes showed more vigorous calcium peaks under osmotic stress than under mechanical stimuli, while an opposite trend was found for ATDC5 cells. Extracellular calcium source, intracellular ER store, and PLC/IP3 pathway each played significant roles in the calcium responses of ATDC5 cells under both osmotic and mechanical stimuli. However, high level shear stress can directly cause ER release in primary cells without the presence of extracellular Ca2+ or involvement of PLC-IP3 pathway. TRPV4 channel is essential for the responses of ATDC5 cells, but not for primary chondrocytes. In contrast, inhibition of mechano-sensitive channels had no significant effects on the ATDC5 cells. Therefore, primary chondrocytes and ATDC5 cells rely on distinct calcium sources and ion channels to initiate intracellular calcium signaling. Together, these results contribute to our understanding of stimulation-induced calcium signaling in primary chondrocytes and ATDC5 cells, and the different roles of three essential pathways between the two cell types.
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Affiliation(s)
- Wen Li
- Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
| | - Yilu Zhou
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Lin Han
- School of Biomedical Engineering, Science & Health Systems, Drexel University, Philadelphia, PA 19104, United States
| | - Liyun Wang
- Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
| | - X Lucas Lu
- Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States.
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Xu W, Zhu J, Hu J, Xiao L. Engineering the biomechanical microenvironment of chondrocytes towards articular cartilage tissue engineering. Life Sci 2022; 309:121043. [DOI: 10.1016/j.lfs.2022.121043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/24/2022] [Accepted: 10/02/2022] [Indexed: 11/28/2022]
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Mechanosignalling in cartilage: an emerging target for the treatment of osteoarthritis. Nat Rev Rheumatol 2021; 18:67-84. [PMID: 34934171 DOI: 10.1038/s41584-021-00724-w] [Citation(s) in RCA: 102] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2021] [Indexed: 12/12/2022]
Abstract
Mechanical stimuli have fundamental roles in articular cartilage during health and disease. Chondrocytes respond to the physical properties of the cartilage extracellular matrix (ECM) and the mechanical forces exerted on them during joint loading. In osteoarthritis (OA), catabolic processes degrade the functional ECM and the composition and viscoelastic properties of the ECM produced by chondrocytes are altered. The abnormal loading environment created by these alterations propagates cell dysfunction and inflammation. Chondrocytes sense their physical environment via an array of mechanosensitive receptors and channels that activate a complex network of downstream signalling pathways to regulate several cell processes central to OA pathology. Advances in understanding the complex roles of specific mechanosignalling mechanisms in healthy and OA cartilage have highlighted molecular processes that can be therapeutically targeted to interrupt pathological feedback loops. The potential for combining these mechanosignalling targets with the rapidly expanding field of smart mechanoresponsive biomaterials and delivery systems is an emerging paradigm in OA treatment. The continued advances in this field have the potential to enable restoration of healthy mechanical microenvironments and signalling through the development of precision therapeutics, mechanoregulated biomaterials and drug systems in the near future.
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Inflammatory signaling sensitizes Piezo1 mechanotransduction in articular chondrocytes as a pathogenic feed-forward mechanism in osteoarthritis. Proc Natl Acad Sci U S A 2021; 118:2001611118. [PMID: 33758095 PMCID: PMC8020656 DOI: 10.1073/pnas.2001611118] [Citation(s) in RCA: 93] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Osteoarthritis is a global health problem that affects load-bearing joints, causing loss of mobility and enormous healthcare costs. However, disease-modifying approaches are lacking. Here, we report a cellular mechanism of inflammatory signaling in chondrocytes, the cellular component of cartilage. We show how osteoarthritis-relevant levels of interleukin-1α reprogram articular chondrocytes so that they become more susceptible to mechanical trauma, which chondrocytes sense via Piezo1/2-mechanosensitive ion channels. We uncover that IL-1α enhances gene expression of Piezo1 in primary articular chondrocytes underlying Piezo1 enhanced function. We elucidate signaling from membrane to nucleus, including transcription factors that enhance Piezo1 expression. We also define consequences of increased expression of Piezo1, for mechanotransduction and at rest, that implicate this reprogramming mechanism in osteoarthritis pathogenesis. Osteoarthritis (OA) is a painful and debilitating condition of synovial joints without any disease-modifying therapies [A. M. Valdes, T. D. Spector, Nat. Rev. Rheumatol. 7, 23–32 (2011)]. We previously identified mechanosensitive PIEZO channels, PIEZO1 and PIEZO2, both expressed in articular cartilage, to function in chondrocyte mechanotransduction in response to injury [W. Lee et al., Proc. Natl. Acad. Sci. U.S.A. 111, E5114–E5122 (2014); W. Lee, F. Guilak, W. Liedtke, Curr. Top. Membr. 79, 263–273 (2017)]. We therefore asked whether interleukin-1–mediated inflammatory signaling, as occurs in OA, influences Piezo gene expression and channel function, thus indicative of maladaptive reprogramming that can be rationally targeted. Primary porcine chondrocyte culture and human osteoarthritic cartilage tissue were studied. We found that interleukin-1α (IL-1α) up-regulated Piezo1 in porcine chondrocytes. Piezo1 expression was significantly increased in human osteoarthritic cartilage. Increased Piezo1 expression in chondrocytes resulted in a feed-forward pathomechanism whereby increased function of Piezo1 induced excess intracellular Ca2+ at baseline and in response to mechanical deformation. Elevated resting state Ca2+ in turn rarefied the F-actin cytoskeleton and amplified mechanically induced deformation microtrauma. As intracellular substrates of this OA-related inflammatory pathomechanism, in porcine articular chondrocytes exposed to IL-1α, we discovered that enhanced Piezo1 expression depended on p38 MAP-kinase and transcription factors HNF4 and ATF2/CREBP1. CREBP1 directly bound to the proximal PIEZO1 gene promoter. Taken together, these signaling and genetic reprogramming events represent a detrimental Ca2+-driven feed-forward mechanism that can be rationally targeted to stem the progression of OA.
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Guilak F, Hayes AJ, Melrose J. Perlecan in Pericellular Mechanosensory Cell-Matrix Communication, Extracellular Matrix Stabilisation and Mechanoregulation of Load-Bearing Connective Tissues. Int J Mol Sci 2021; 22:2716. [PMID: 33800241 PMCID: PMC7962540 DOI: 10.3390/ijms22052716] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/04/2021] [Accepted: 03/05/2021] [Indexed: 12/14/2022] Open
Abstract
In this study, we review mechanoregulatory roles for perlecan in load-bearing connective tissues. Perlecan facilitates the co-acervation of tropoelastin and assembly of elastic microfibrils in translamellar cross-bridges which, together with fibrillin and elastin stabilise the extracellular matrix of the intervertebral disc annulus fibrosus. Pericellular perlecan interacts with collagen VI and XI to define and stabilize this matrix compartment which has a strategic position facilitating two-way cell-matrix communication between the cell and its wider extracellular matrix. Cues from the extracellular matrix are fed through this pericellular matrix back to the chondrocyte, allowing it to perceive and respond to subtle microenvironmental changes to regulate tissue homeostasis. Thus perlecan plays a key regulatory role in chondrocyte metabolism, and in chondrocyte differentiation. Perlecan acts as a transport proteoglycan carrying poorly soluble, lipid-modified proteins such as the Wnt or Hedgehog families facilitating the establishment of morphogen gradients that drive tissue morphogenesis. Cell surface perlecan on endothelial cells or osteocytes acts as a flow sensor in blood and the lacunar canalicular fluid providing feedback cues to smooth muscle cells regulating vascular tone and blood pressure, and the regulation of bone metabolism by osteocytes highlighting perlecan's multifaceted roles in load-bearing connective tissues.
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Affiliation(s)
- Farshid Guilak
- Department of Orthopaedic Surgery, Washington University, St. Louis, MO 63110, USA;
- Shriners Hospitals for Children—St. Louis, St. Louis, MO 63110, USA
| | - Anthony J. Hayes
- Bioimaging Research Hub, Cardiff School of Biosciences, Cardiff University, Cardiff, Wales CF10 3AX, UK;
| | - James Melrose
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW 2052, Australia
- Raymond Purves Laboratory, Institute of Bone and Joint Research, Kolling Institute, Northern Sydney Local Health District, Royal North Shore Hospital, St. Leonards, NSW 2065, Australia
- Sydney Medical School, Northern, University of Sydney at Royal North Shore Hospital, St. Leonards, NSW 2065, Australia
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Takeda Y, Niki Y, Fukuhara Y, Fukuda Y, Udagawa K, Shimoda M, Kikuchi T, Kobayashi S, Harato K, Miyamoto T, Matsumoto M, Nakamura M. Compressive mechanical stress enhances susceptibility to interleukin-1 by increasing interleukin-1 receptor expression in 3D-cultured ATDC5 cells. BMC Musculoskelet Disord 2021; 22:238. [PMID: 33648469 PMCID: PMC7923672 DOI: 10.1186/s12891-021-04095-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 02/17/2021] [Indexed: 12/31/2022] Open
Abstract
Background Mechanical overload applied on the articular cartilage may play an important role in the pathogenesis of osteoarthritis. However, the mechanism of chondrocyte mechanotransduction is not fully understood. The purpose of this study was to assess the effects of compressive mechanical stress on interleukin-1 receptor (IL-1R) and matrix-degrading enzyme expression by three-dimensional (3D) cultured ATDC5 cells. In addition, the implications of transient receptor potential vanilloid 4 (TRPV4) channel regulation in promoting effects of compressive mechanical loading were elucidated. Methods ATDC5 cells were cultured in alginate beads with the growth medium containing insulin-transferrin-selenium and BMP-2 for 6 days. The cultured cell pellet was seeded in collagen scaffolds to produce 3D-cultured constructs. Cyclic compressive loading was applied on the 3D-cultured constructs at 0.5 Hz for 3 h. The mRNA expressions of a disintegrin and metalloproteinases with thrombospondin motifs 4 (ADAMTS4) and IL-1R were determined with or without compressive loading, and effects of TRPV4 agonist/antagonist on mRNA expressions were examined. Immunoreactivities of reactive oxygen species (ROS), TRPV4 and IL-1R were assessed in 3D-cultured ATDC5 cells. Results In 3D-cultured ATDC5 cells, ROS was induced by cyclic compressive loading stress. The mRNA expression levels of ADAMTS4 and IL-1R were increased by cyclic compressive loading, which was mostly prevented by pyrollidine dithiocarbamate. Small amounts of IL-1β upregulated ADAMTS4 and IL-1R mRNA expressions only when combined with compressive loading. TRPV4 agonist suppressed ADAMTS4 and IL-1R mRNA levels induced by the compressive loading, whereas TRPV4 antagonist enhanced these levels. Immunoreactivities to TRPV4 and IL-1R significantly increased in constructs with cyclic compressive loading. Conclusion Cyclic compressive loading induced mRNA expressions of ADAMTS4 and IL-1R through reactive oxygen species. TRPV4 regulated these mRNA expressions, but excessive compressive loading may impair TRPV4 regulation. These findings suggested that TRPV4 regulates the expression level of IL-1R and subsequent IL-1 signaling induced by cyclic compressive loading and participates in cartilage homeostasis. Supplementary Information The online version contains supplementary material available at 10.1186/s12891-021-04095-x.
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Affiliation(s)
- Yuki Takeda
- Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Yasuo Niki
- Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
| | - Yusuke Fukuhara
- Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Yoshitsugu Fukuda
- Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Kazuhiko Udagawa
- Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Masayuki Shimoda
- Department of Pathology, School of Medicine, Keio University, Tokyo, Japan
| | - Toshiyuki Kikuchi
- Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Shu Kobayashi
- Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Kengo Harato
- Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Takeshi Miyamoto
- Department of Orthopaedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Morio Matsumoto
- Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Masaya Nakamura
- Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
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Krogman W, Sparks JA, Blancaflor EB. Cell Type-Specific Imaging of Calcium Signaling in Arabidopsis thaliana Seedling Roots Using GCaMP3. Int J Mol Sci 2020; 21:ijms21176385. [PMID: 32887481 PMCID: PMC7503278 DOI: 10.3390/ijms21176385] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 02/07/2023] Open
Abstract
Cytoplasmic calcium ([Ca2+]cyt) is a well-characterized second messenger in eukaryotic cells. An elevation in [Ca2+]cyt levels is one of the earliest responses in plant cells after exposure to a range of environmental stimuli. Advances in understanding the role of [Ca2+]cyt in plant development has been facilitated by the use of genetically-encoded reporters such as GCaMP. Most of these studies have relied on promoters such as Cauliflower Mosaic Virus (35S) and Ubiquitin10 (UBQ10) to drive expression of GCaMP in all cell/tissue types. Plant organs such as roots consist of various cell types that likely exhibit unique [Ca2+]cyt responses to exogenous and endogenous signals. However, few studies have addressed this question. Here, we introduce a set of Arabidopsis thaliana lines expressing GCaMP3 in five root cell types including the columella, endodermis, cortex, epidermis, and trichoblasts. We found similarities and differences in the [Ca2+]cyt signature among these root cell types when exposed to adenosine tri-phosphate (ATP), glutamate, aluminum, and salt, which are known to trigger [Ca2+]cyt increases in root cells. These cell type-targeted GCaMP3 lines provide a new resource that should enable more in depth studies that address how a particular environmental stimulus is linked to specific root developmental pathways via [Ca2+]cyt.
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Okada Y, Okada T, Sato-Numata K, Islam MR, Ando-Akatsuka Y, Numata T, Kubo M, Shimizu T, Kurbannazarova RS, Marunaka Y, Sabirov RZ. Cell Volume-Activated and Volume-Correlated Anion Channels in Mammalian Cells: Their Biophysical, Molecular, and Pharmacological Properties. Pharmacol Rev 2019; 71:49-88. [PMID: 30573636 DOI: 10.1124/pr.118.015917] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
There are a number of mammalian anion channel types associated with cell volume changes. These channel types are classified into two groups: volume-activated anion channels (VAACs) and volume-correlated anion channels (VCACs). VAACs can be directly activated by cell swelling and include the volume-sensitive outwardly rectifying anion channel (VSOR), which is also called the volume-regulated anion channel; the maxi-anion channel (MAC or Maxi-Cl); and the voltage-gated anion channel, chloride channel (ClC)-2. VCACs can be facultatively implicated in, although not directly activated by, cell volume changes and include the cAMP-activated cystic fibrosis transmembrane conductance regulator (CFTR) anion channel, the Ca2+-activated Cl- channel (CaCC), and the acid-sensitive (or acid-stimulated) outwardly rectifying anion channel. This article describes the phenotypical properties and activation mechanisms of both groups of anion channels, including accumulating pieces of information on the basis of recent molecular understanding. To that end, this review also highlights the molecular identities of both anion channel groups; in addition to the molecular identities of ClC-2 and CFTR, those of CaCC, VSOR, and Maxi-Cl were recently identified by applying genome-wide approaches. In the last section of this review, the most up-to-date information on the pharmacological properties of both anion channel groups, especially their half-maximal inhibitory concentrations (IC50 values) and voltage-dependent blocking, is summarized particularly from the standpoint of pharmacological distinctions among them. Future physiologic and pharmacological studies are definitely warranted for therapeutic targeting of dysfunction of VAACs and VCACs.
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Affiliation(s)
- Yasunobu Okada
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Toshiaki Okada
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Kaori Sato-Numata
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Md Rafiqul Islam
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Yuhko Ando-Akatsuka
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Tomohiro Numata
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Machiko Kubo
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Takahiro Shimizu
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Ranohon S Kurbannazarova
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Yoshinori Marunaka
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Ravshan Z Sabirov
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
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Molecular Identities and ATP Release Activities of Two Types of Volume-Regulatory Anion Channels, VSOR and Maxi-Cl. CURRENT TOPICS IN MEMBRANES 2018; 81:125-176. [PMID: 30243431 DOI: 10.1016/bs.ctm.2018.07.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
An elaborate volume regulation system based on interplay of ion channels and transporters was evolved to cope with constant osmotic challenges caused by intensive metabolism, transport and other physiological/pathophysiological events. In animal cells, two types of anion channels are directly activated by cell swelling and involved in the regulatory volume decrease (RVD): volume-sensitive outwardly rectifying anion channel (VSOR), also called volume-regulated anion channel (VRAC), and Maxi-Cl which is the most major type of maxi-anion channel (MAC). These two channels have very different biophysical profiles and exhibit opposite dependence on intracellular ATP. After several decades of verifying many false-positive candidates for VSOR and Maxi-Cl, LRRC8 family proteins emerged as major VSOR components, and SLCO2A1 protein as a core of Maxi-Cl. Still, neither of these proteins alone can fully reproduce the native channel phenotypes suggesting existence of missing components. Although both VSOR and Maxi-Cl have pores wide enough to accommodate bulky ATP4- and MgATP2- anions, evidence accumulated hitherto, based on pharmacological and gene silencing experiments, suggests that Maxi-Cl, but not VSOR, serves as one of the major pathways for the release of ATP from swollen and ischemic/hypoxic cells. Relations of VSOR and Maxi-Cl with diseases and their selective pharmacology are the topics promoted by recent advance in molecular identification of the two volume-activated, volume-regulatory anion channels.
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Abstract
Microfluidics is an interdisciplinary field intersecting many areas in engineering. Utilizing a combination of physics, chemistry, biology, and biotechnology, along with practical applications for designing devices that use low volumes of fluids to achieve high-throughput screening, is a major goal in microfluidics. Microfluidic approaches allow the study of cells growth and differentiation using a variety of conditions including control of fluid flow that generates shear stress. Recently, Piezo1 channels were shown to respond to fluid shear stress and are crucial for vascular development. This channel is ideal for studying fluid shear stress applied to cells using microfluidic devices. We have developed an approach that allows us to analyze the role of Piezo channels on any given cell and serves as a high-throughput screen for drug discovery. We show that this approach can provide detailed information about the inhibitors of Piezo channels.
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Haase K, Shendruk TN, Pelling AE. Rapid dynamics of cell-shape recovery in response to local deformations. SOFT MATTER 2017; 13:567-577. [PMID: 27942684 DOI: 10.1039/c6sm02560a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
It is vital that cells respond rapidly to mechanical cues within their microenvironment through changes in cell shape and volume, which rely upon the mechanical properties of cells' highly interconnected cytoskeletal networks and intracellular fluid redistributions. While previous research has largely investigated deformation mechanics, we now focus on the immediate cell-shape recovery response following mechanical perturbation by inducing large, local, and reproducible cellular deformations using AFM. By continuous imaging within the plane of deformation, we characterize the membrane and cortical response of HeLa cells to unloading, and model the recovery via overdamped viscoelastic dynamics. Importantly, the majority (90%) of HeLa cells recover their cell shape in <1 s. Despite actin remodelling on this time scale, we show that cell-shape recovery time is not affected by load duration, nor magnitude for untreated cells. To further explore this rapid recovery response, we expose cells to cytoskeletal destabilizers and osmotic shock conditions, which uncovers the interplay between actin and osmotic pressure. We show that the rapid dynamics of recovery depend crucially on intracellular pressure, and provide strong evidence that cortical actin is the key regulator in the cell-shape recovery processes, in both cancerous and non-cancerous epithelial cells.
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Affiliation(s)
- Kristina Haase
- Department of Physics, University of Ottawa, MacDonald Hall, 150 Louis Pasteur, Canada.
| | - Tyler N Shendruk
- The Rudolf Peierls Centre for Theoretical Physics, Department of Physics, University of Oxford, 1 Keble Road, Oxford, OX1 3NP, UK
| | - Andrew E Pelling
- Department of Physics, University of Ottawa, MacDonald Hall, 150 Louis Pasteur, Canada. and Department of Biology, University of Ottawa, Gendron Hall, 30 Marie Curie, Canada and Institute for Science, Society and Policy, University of Ottawa, Simard Hall, 60 University, Ottawa, ON K1N 6N5, Canada and SymbioticA, School of Anatomy, Physiology and Human Biology, University of Western Australia, Perth WA 6009, Australia
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Itokazu M, Wakitani S, Mera H, Tamamura Y, Sato Y, Takagi M, Nakamura H. Transplantation of Scaffold-Free Cartilage-Like Cell-Sheets Made from Human Bone Marrow Mesenchymal Stem Cells for Cartilage Repair: A Preclinical Study. Cartilage 2016; 7:361-72. [PMID: 27688844 PMCID: PMC5029565 DOI: 10.1177/1947603515627342] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVE The object of this study was to determine culture conditions that create stable scaffold-free cartilage-like cell-sheets from human bone marrow-derived mesenchymal stem cells (hBMSCs) and to assess their effects after transplantation into osteochondral defects in nude rats. DESIGN (Experiment 1) The hBMSCs were harvested from 3 males, the proliferative and chondrogenic capacities were assessed at passage 1, and the cells were expanded in 3 different culture conditions: (1) 5% fetal bovine serum (FBS), (2) 10% FBS, and (3) 5% FBS with fibroblast growth factor 2 (FGF-2). The cells were harvested and made chondrogenic pellet culture. The cell proliferation rate, glycosaminoglycan/DNA ratio, and safranin-O staining intensity of pellets cultured condition 3 were higher than those of conditions 1 and 2. (Experiment 2) The hBMSCs were expanded and passaged 3 times under culture condition 3, and fabricate the cell-sheets in chondrogenic medium either with or without FBS. The cell-sheets fabricated with FBS maintained their size with flat edges. (Experiment 3) The cell-sheets were transplanted into osteochondral defects in nude rats. Histological analysis was performed at 2, 4, and 12 weeks after surgery. RESULTS The osteochondral repair was better after sheet transplantation than in the control group and significantly improved Wakitani score. Immunostaining with human-specific vimentin antibody showed that the transplanted cells became fewer and disappeared at 12 weeks. CONCLUSIONS These results indicate that culture with FGF-2 may help to quickly generate sufficient numbers of cells to create stable and reliable scaffold-free cartilage-like cell-sheets, which contribute to the regeneration of osteochondral defects.
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Affiliation(s)
- Maki Itokazu
- Department of Orthopedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan,School of Health and Sports Science, Mukogawa Women’s University, Nishinomiya, Japan
| | - Shigeyuki Wakitani
- School of Health and Sports Science, Mukogawa Women’s University, Nishinomiya, Japan,Department of Artificial Joint & Biomaterials Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan,Shigeyuki Wakitani, Department of Artificial Joint & Biomaterials Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan, 1-2-3 Kasumi, Minami-ku, Hiroshima 739-8553, Japan.
| | - Hisashi Mera
- School of Health and Sports Science, Mukogawa Women’s University, Nishinomiya, Japan,International Medical Device Alliance, Foundation for Biomedical Research and Innovation, Kobe, Japan
| | - Yoshihiro Tamamura
- School of Health and Sports Science, Mukogawa Women’s University, Nishinomiya, Japan
| | - Yasushi Sato
- Laboratory of Cell Processing Engineering, Division of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo, Japan
| | - Mutsumi Takagi
- Laboratory of Cell Processing Engineering, Division of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo, Japan
| | - Hiroaki Nakamura
- Department of Orthopedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan
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Wang Z, Wann A, Thompson C, Hassen A, Wang W, Knight M. IFT88 influences chondrocyte actin organization and biomechanics. Osteoarthritis Cartilage 2016; 24:544-54. [PMID: 26493329 PMCID: PMC4769095 DOI: 10.1016/j.joca.2015.10.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 10/06/2015] [Accepted: 10/12/2015] [Indexed: 02/07/2023]
Abstract
OBJECTIVES Primary cilia are microtubule based organelles which control a variety of signalling pathways important in cartilage development, health and disease. This study examines the role of the intraflagellar transport (IFT) protein, IFT88, in regulating fundamental actin organisation and mechanics in articular chondrocytes. METHODS The study used an established chondrocyte cell line with and without hypomorphic mutation of IFT88 (IFT88(orpk)). Confocal microscopy was used to quantify F-actin and myosin IIB organisation. Viscoelastic cell and actin cortex mechanics were determined using micropipette aspiration with actin dynamics visualised in live cells transfected with LifeACT-GFP. RESULTS IFT88(orpk) cells exhibited a significant increase in acto-myosin stress fibre organisation relative to wild-type (WT) cells in monolayer and an altered response to cytochalasin D. Rounded IFT88(orpk) cells cultured in suspension exhibited reduced cortical actin expression with reduced cellular equilibrium modulus. Micropipette aspiration resulted in reduced membrane bleb formation in IFT88(orpk) cells. Following membrane blebbing, IFT88(orpk) cells exhibited slower reformation of the actin cortex. IFT88(orpk) cells showed increased actin deformability and reduced cortical tension confirming that IFT regulates actin cortex mechanics. The reduced cortical tension is also consistent with the reduced bleb formation. CONCLUSIONS This study demonstrates for the first time that the ciliary protein IFT88 regulates fundamental actin organisation and the stiffness of the actin cortex leading to alterations in cell deformation, mechanical properties and blebbing in an IFT88 chondrocyte cell line. This adds to the growing understanding of the role of primary cilia and IFT in regulating cartilage biology.
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Affiliation(s)
- Z. Wang
- Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
| | - A.K.T. Wann
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
| | - C.L. Thompson
- Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom,Address correspondence and reprint requests to: C.L. Thompson, School of Engineering and Materials Science, Queen Mary University of London, Mile end Rd, London, E1 4NS, United Kingdom. Tel: 44-(0)20-7882-8868.
| | - A. Hassen
- Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
| | - W. Wang
- Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
| | - M.M. Knight
- Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
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Changes in Ultrastructure and Cytoskeletal Aspects of Human Normal and Osteoarthritic Chondrocytes Exposed to Interleukin-1β and Cyclical Hydrostatic Pressure. Int J Mol Sci 2015; 16:26019-34. [PMID: 26528971 PMCID: PMC4661795 DOI: 10.3390/ijms161125936] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/03/2015] [Accepted: 10/21/2015] [Indexed: 12/23/2022] Open
Abstract
The aim of this study was to examine the ultrastructure and cytoskeletal organization in human normal and Osteoarhritic (OA) chondrocytes, exposed to interleukin-1β (IL-1β) and cyclic hydrostatic pressure (HP). Morphological examination by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) revealed differences between normal and OA chondrocytes at the nuclear and cytoplasmic level. IL-1β (5 ng/mL) induced a decrease of the number of mitochondria and Golgi bodies and a significant increase on the percentage of cells rich in vacuolization and in marginated chromatin. Cyclical HP (1–5 MPa, 0.25 Hz, for 3 h) did not change the morphology of normal chondrocytes, but had a beneficial effect on OA chondrocytes increasing the number of organelles. Normal and OA cells subjected to IL-1β and HP recovered cytoplasmic ultrastructure. Immunofluorescence (IF) examination of normal chondrocytes showed an actin signal polarized on the apical sides of the cytoplasm, tubulin and vimentin uniformly distributed throughout cytoplasm and vinculin revealed a punctuated pattern under the plasma membrane. In OA chondrocytes, these proteins partially lost their organization. Stimulation with IL-1β caused, in both type of cells, modification in the cytoskeletal organization; HP counteracted the negative effects of IL-1β. Our results showed structural differences at nuclear, cytoplasmic and cytoskeletal level between normal and OA chondrocytes. IL-1β induced ultrastructural and cytoskeletal modifications, counteracted by a cyclical low HP.
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Zhou Y, David MA, Chen X, Wan LQ, Duncan RL, Wang L, Lu XL. Effects of Osmolarity on the Spontaneous Calcium Signaling of In Situ Juvenile and Adult Articular Chondrocytes. Ann Biomed Eng 2015. [PMID: 26219403 DOI: 10.1007/s10439-015-1406-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Calcium is a universal second messenger that mediates the metabolic activity of chondrocytes in articular cartilage. Spontaneous intracellular calcium ([Ca(2+)]i) oscillations, similar to those in neurons and myocytes, have recently been observed in chondrocytes. This study analyzed and compared the effects of different osmotic environments (hypertonic, hypotonic, and isotonic) on the spontaneous [Ca(2+)]i signaling of in situ chondrocytes residing in juvenile and adult cartilage explants. In spite of a lower cell density, a significantly higher percentage of chondrocytes in adult cartilage under all osmotic environments demonstrated spontaneous [Ca(2+)]i oscillations than chondrocytes in juvenile cartilage. For both juvenile and adult chondrocytes, hypotonic stress increased while hypertonic stress decreased the response rates. Furthermore, the spatiotemporal characteristics of the [Ca(2+)]i peaks vary in an age-dependent manner. In the hypotonic environment, the [Ca(2+)]i oscillation frequency of responsive adult cells is almost tripled whereas the juvenile cells respond with an increased duration and magnitude of each [Ca(2+)]i peak. Both juvenile and adult chondrocytes demonstrated significantly slower [Ca(2+)]i oscillations with longer rising and recovery time under the hypertonic condition. Taken together, these results shed new insights into the interplay between age and osmotic environment that may regulate the fundamental metabolism of chondrocytes.
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Affiliation(s)
- Yilu Zhou
- Department of Mechanical Engineering, University of Delaware, 130 Academy Street SPL126, Newark, DE, 19716, USA
| | - Michael A David
- Department of Biomedical Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Xingyu Chen
- Department of Mechanical Engineering, University of Delaware, 130 Academy Street SPL126, Newark, DE, 19716, USA
| | - Leo Q Wan
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Randall L Duncan
- Department of Biological Sciences, University of Delaware, Newark, DE, 19716, USA
| | - Liyun Wang
- Department of Mechanical Engineering, University of Delaware, 130 Academy Street SPL126, Newark, DE, 19716, USA
| | - X Lucas Lu
- Department of Mechanical Engineering, University of Delaware, 130 Academy Street SPL126, Newark, DE, 19716, USA.
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Zelenski NA, Leddy HA, Sanchez-Adams J, Zhang J, Bonaldo P, Liedtke W, Guilak F. Type VI Collagen Regulates Pericellular Matrix Properties, Chondrocyte Swelling, and Mechanotransduction in Mouse Articular Cartilage. Arthritis Rheumatol 2015; 67:1286-94. [PMID: 25604429 DOI: 10.1002/art.39034] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/13/2015] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Mechanical factors play a critical role in the physiology and pathology of articular cartilage, although the mechanisms of mechanical signal transduction are not fully understood. We undertook this study to test the hypothesis that type VI collagen is necessary for mechanotransduction in articular cartilage by determining the effects of type VI collagen knockout on the activation of the mechano-osmosensitive, calcium-permeable channel TRPV4 (transient receptor potential vanilloid channel 4) as well as on osmotically induced chondrocyte swelling and pericellular matrix (PCM) mechanical properties. METHODS Confocal laser scanning microscopy was used to image TRPV4-mediated calcium signaling and osmotically induced cell swelling in intact femora from 2- and 9-month-old wild-type (WT) and type VI collagen-deficient (Col6a1(-/-)) mice. Immunofluorescence-guided atomic force microscopy was used to map PCM mechanical properties based on the presence of perlecan. RESULTS Hypo-osmotic stress-induced TRPV4-mediated calcium signaling was increased in Col6a1(-/-) mice relative to WT controls at 2 months. Col6a1(-/-) mice exhibited significantly increased osmotically induced cell swelling and decreased PCM moduli relative to WT controls at both ages. CONCLUSION In contrast to our original hypothesis, type VI collagen was not required for TRPV4-mediated Ca(2+) signaling; however, knockout of type VI collagen altered the mechanical properties of the PCM, which in turn increased the extent of cell swelling and osmotically induced TRPV4 signaling in an age-dependent manner. These findings emphasize the role of the PCM as a transducer of mechanical and physicochemical signals, and they suggest that alterations in PCM properties, as may occur with aging or osteoarthritis, can influence mechanotransduction via TRPV4 or other ion channels.
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McNulty AL, Leddy HA, Liedtke W, Guilak F. TRPV4 as a therapeutic target for joint diseases. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2015; 388:437-50. [PMID: 25519495 PMCID: PMC4361386 DOI: 10.1007/s00210-014-1078-x] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 12/04/2014] [Indexed: 02/07/2023]
Abstract
Biomechanical factors play a critical role in regulating the physiology as well as the pathology of multiple joint tissues and have been implicated in the pathogenesis of osteoarthritis. Therefore, the mechanisms by which cells sense and respond to mechanical signals may provide novel targets for the development of disease-modifying osteoarthritis drugs (DMOADs). Transient receptor potential vanilloid 4 (TRPV4) is a Ca(2+)-permeable cation channel that serves as a sensor of mechanical or osmotic signals in several musculoskeletal tissues, including cartilage, bone, and synovium. The importance of TRPV4 in joint homeostasis is apparent in patients harboring TRPV4 mutations, which result in the development of a spectrum of skeletal dysplasias and arthropathies. In addition, the genetic knockout of Trpv4 results in the development of osteoarthritis and decreased osteoclast function. In engineered cartilage replacements, chemical activation of TRPV4 can reproduce many of the anabolic effects of mechanical loading to accelerate tissue growth and regeneration. Overall, TRPV4 plays a key role in transducing mechanical, pain, and inflammatory signals within joint tissues and thus is an attractive therapeutic target to modulate the effects of joint diseases. In pathological conditions in the joint, when the delicate balance of TRPV4 activity is altered, a variety of different tools could be utilized to directly or indirectly target TRPV4 activity.
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Affiliation(s)
- Amy L. McNulty
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC 27710
| | - Holly A. Leddy
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC 27710
| | - Wolfgang Liedtke
- Department of Neurology and Duke University Clinics for Pain and Palliative Care, Duke University Medical Center, Durham, NC 27710
| | - Farshid Guilak
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC 27710
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The rate of hypo-osmotic challenge influences regulatory volume decrease (RVD) and mechanical properties of articular chondrocytes. Osteoarthritis Cartilage 2015; 23:289-99. [PMID: 25450844 DOI: 10.1016/j.joca.2014.11.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 10/23/2014] [Accepted: 11/03/2014] [Indexed: 02/02/2023]
Abstract
OBJECTIVES Osteoarthritis (OA) is associated with a gradual reduction in the interstitial osmotic pressure within articular cartilage. The aim of this study was to compare the effects of sudden and gradual hypo-osmotic challenge on chondrocyte morphology and biomechanics. METHODS Bovine articular chondrocytes were exposed to a reduction in extracellular osmolality from 327 to 153 mOsmol/kg applied either suddenly (<5 s) or gradually (over 180 min). Temporal changes in cell diameter and the existence of regulatory volume decrease (RVD) were quantified along with changes in cortical actin and chromatin condensation. The cellular viscoelastic mechanical properties were determined by micropipette aspiration. RESULTS In response to a sudden hypo-osmotic stress, 66% of chondrocytes exhibited an increase in diameter followed by RVD, whilst 25% showed no RVD. By contrast, cells exposed to gradual hypo-osmotic stress exhibited reduced cell swelling without subsequent RVD. There was an increase in the equilibrium modulus for cells exposed to sudden hypo-osmotic stress. However, gradual hypo-osmotic challenge had no effect on cell mechanical properties. This cell stiffening response to sudden hypo-osmotic challenge was abolished when actin organization was disrupted with cytochalasin D or RVD inhibited with REV5901. Both sudden and gradual hypo-osmotic challenge reduced cortical F-actin distribution and caused chromatin decondensation. CONCLUSIONS Sudden hypo-osmotic challenge increases chondrocyte mechanics by activation of RVD and interaction with the actin cytoskeleton. Moreover, the rate of hypo-osmotic challenge is shown to have a profound effect on chondrocyte morphology and biomechanics. This important phenomenon needs to be considered when studying the response of chondrocytes to pathological hypo-osmotic stress.
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Hdud IM, Mobasheri A, Loughna PT. Effect of osmotic stress on the expression of TRPV4 and BKCa channels and possible interaction with ERK1/2 and p38 in cultured equine chondrocytes. Am J Physiol Cell Physiol 2014; 306:C1050-7. [DOI: 10.1152/ajpcell.00287.2013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The metabolic activity of articular chondrocytes is influenced by osmotic alterations that occur in articular cartilage secondary to mechanical load. The mechanisms that sense and transduce mechanical signals from cell swelling and initiate volume regulation are poorly understood. The purpose of this study was to investigate how the expression of two putative osmolyte channels [transient receptor potential vanilloid 4 (TRPV4) and large-conductance Ca2+-activated K+ (BKCa)] in chondrocytes is modulated in different osmotic conditions and to examine a potential role for MAPKs in this process. Isolated equine articular chondrocytes were subjected to anisosmotic conditions, and TRPV4 and BKCa channel expression and ERK1/2 and p38 MAPK protein phosphorylation were investigated using Western blotting. Results indicate that the TRPV4 channel contributes to the early stages of hypo-osmotic stress, while the BKCa channel is involved in responding to elevated intracellular Ca2+ and mediating regulatory volume decrease. ERK1/2 is phosphorylated by hypo-osmotic stress ( P < 0.001), and p38 MAPK is phosphorylated by hyperosmotic stress ( P < 0.001). In addition, this study demonstrates the importance of endogenous ERK1/2 phosphorylation in TRPV4 channel expression, where blocking ERK1/2 by a specific inhibitor (PD98059) prevented increased levels of the TRPV4 channel in cells exposed to hypo-osmotic stress and decreased TRPV4 channel expression to below control levels in iso-osmotic conditions ( P < 0.001).
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Affiliation(s)
- Ismail M. Hdud
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, The University of Nottingham, Sutton Bonington Campus, Leicestershire, United Kingdom
| | - Ali Mobasheri
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, The University of Nottingham, Sutton Bonington Campus, Leicestershire, United Kingdom
- Medical Research Council-Arthritis Research UK Centre for Musculoskeletal Ageing Research, Nottingham, United Kingdom
- Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, Arthritis Research UK Pain Centre, Queen's Medical Centre, Nottingham, United Kingdom; and
- Center of Excellence in Genomic Medicine Research (CEGMR), King Fahd Medical Research Center (KFMRC), King AbdulAziz University, Jeddah, Kingdom of Saudi Arabia
| | - Paul T. Loughna
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, The University of Nottingham, Sutton Bonington Campus, Leicestershire, United Kingdom
- Medical Research Council-Arthritis Research UK Centre for Musculoskeletal Ageing Research, Nottingham, United Kingdom
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Madden RMJ, Han SK, Herzog W. The effect of compressive loading magnitude on in situ chondrocyte calcium signaling. Biomech Model Mechanobiol 2014; 14:135-42. [PMID: 24853775 PMCID: PMC4282695 DOI: 10.1007/s10237-014-0594-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 05/06/2014] [Indexed: 12/19/2022]
Abstract
Chondrocyte metabolism is stimulated by deformation and is associated with structural changes in the cartilage extracellular matrix (ECM), suggesting that these cells are involved in maintaining tissue health and integrity. Calcium signaling is an initial step in chondrocyte mechanotransduction that has been linked to many cellular processes. Previous studies using isolated chondrocytes proposed loading magnitude as an important factor regulating this response. However, calcium signaling in the intact cartilage differs compared to isolated cells. The purpose of this study was to investigate the effect of loading magnitude on chondrocyte calcium signaling in intact cartilage. We hypothesized that the percentage of cells exhibiting at least one calcium signal increases with increasing load. Fully intact rabbit femoral condyle and patellar bone/cartilage samples were incubated in calcium-sensitive dyes and imaged continuously under compressive loads of 10-40 % strain. Calcium signaling was primarily associated with the dynamic loading phase and greatly increased beyond a threshold deformation of about 10 % nominal tissue strain. There was a trend toward more cells exhibiting calcium signaling as loading magnitude increased (p = 0.133). These results provide novel information toward identifying mechanisms underlying calcium-dependent signaling pathways related to cartilage homeostasis and possibly the onset and progression of osteoarthritis.
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Affiliation(s)
- Ryan M J Madden
- Human Performance Laboratory, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada,
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28
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Weber JF, Waldman SD. Calcium signaling as a novel method to optimize the biosynthetic response of chondrocytes to dynamic mechanical loading. Biomech Model Mechanobiol 2014; 13:1387-97. [PMID: 24696123 DOI: 10.1007/s10237-014-0580-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 03/26/2014] [Indexed: 11/29/2022]
Abstract
Chondrocyte sensitization and desensitization to mechanical stimuli are complex phenomena that have not been fully described. In this study, we investigated the temporal response of chondrocytes to dynamic mechanical loading and whether changes in calcium signaling could be used a predictor of the biosynthetic response. Cell-seeded agarose gels pre-incubated with an intracellular [Formula: see text] dye (Fluo-4) were subjected to dynamic compressive loading under varying conditions (amplitude and duration). Induced changes in Ca(2+) signaling were determined by confocal imaging and matrix biosynthesis by radioisotope incorporation. It was observed that chondrocytes required a minimum amount of stimulation in order to elicit an anabolic response and they quickly became insensitive to the imposed stimulus. The response appeared to be amplitude dependent and could be predicted by measuring resultant changes in Ca(2+) signaling. A positive correlation between Ca(2+) signaling and matrix synthesis was achieved when changes in Ca(2+) signaling was expressed as a relative number of cells experiencing multiple transients. In addition, these changes in Ca(2+) signaling were effective at determining optimal recovery period between successive applications of intermittent mechanical loading, in which full mechanosensitivity was achieved when [Formula: see text] signaling was allowed to return to baseline (control) levels. The use of Ca(2+) signaling to predict the effectiveness of a particular mechanical stimulus as well as to determine optimal refractory periods appears to be advantageous over empirical-based approaches. Future work will investigate the process of Ca(2+) ion sequestration into intracellular stores to elucidate potential desensitization mechanisms to dynamic mechanical loading.
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Affiliation(s)
- Joanna F Weber
- Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON, Canada,
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29
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Drexler S, Wann A, Vincent TL. Are cellular mechanosensors potential therapeutic targets in osteoarthritis? ACTA ACUST UNITED AC 2014. [DOI: 10.2217/ijr.14.15] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Grzelak P, Domzalski M, Majos A, Podgórski M, Stefanczyk L, Krochmalski M, Polguj M. Thickening of the knee joint cartilage in elite weightlifters as a potential adaptation mechanism. Clin Anat 2014; 27:920-8. [PMID: 24648385 DOI: 10.1002/ca.22393] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Revised: 02/03/2014] [Accepted: 02/20/2014] [Indexed: 01/17/2023]
Abstract
Thickening and increase of area of cartilage have been proposed as two alternative mechanisms of cartilage functional adaptation. The latter has been reported in endurance sportsmen. In weightlifters, extreme strain applied to the articular surfaces can result in other forms of adaptation. The aim of this research is to determine whether cartilage thickness is greater in elite weightlifters than in physically inactive men. Weightlifters (13) and 20 controls [age and body mass index (BMI) matched] underwent knee Magnetic Resonance Imaging (MRI). A single sagittal slice of the knee was taken and cartilage thickness was measured in five and six regions of the medial and lateral femoral condyles, respectively. The analyzed segments represented weight-bearing and nonweight-bearing regions. The tibia cartilage in the weight-bearing area was also measured. The time of training onset and its duration in the weightlifter group were recorded. The cartilage was found to be significantly thicker in weightlifters in most of the analyzed regions. The distribution of cartilage thickness on the medial and lateral femoral condyles was similar in both groups. The duration of training was not associated with cartilage thickness, but the time of training onset correlated inversely with cartilage thickness. It is possible that in high-strain sports, joint cartilage can undergo functional adaptation by thickening. Thus, mechanical loading history could exert a postnatal influence on cartilage morphology.
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Affiliation(s)
- Piotr Grzelak
- Department of Radiology and Diagnostic Imaging, Medical University of Lodz, Poland
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31
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Widmyer MR, Utturkar GM, Leddy HA, Coleman JL, Spritzer CE, Moorman CT, DeFrate LE, Guilak F. High body mass index is associated with increased diurnal strains in the articular cartilage of the knee. ACTA ACUST UNITED AC 2014; 65:2615-22. [PMID: 23818303 DOI: 10.1002/art.38062] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 06/10/2013] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Obesity is an important risk factor for osteoarthritis (OA) and is associated with changes in both the biomechanical and inflammatory environments within the joint. However, the relationship between obesity and cartilage deformation is not fully understood. The goal of this study was to determine the effects of body mass index (BMI) on the magnitude of diurnal cartilage strain in the knee. METHODS Three-dimensional maps of knee cartilage thickness were developed from 3T magnetic resonance images of the knees of asymptomatic age- and sex-matched subjects with normal BMI (18.5-24.9 kg/m2) or high BMI (25-31 kg/m2). Site-specific magnitudes of diurnal cartilage strain were determined using aligned images recorded at 8:00 AM and 4:00 PM on the same day. RESULTS Subjects with high BMI had significantly thicker cartilage on both the patella and femoral groove, as compared to subjects with normal BMI. Diurnal cartilage strains were dependent on location in the knee joint, as well as BMI. Subjects with high BMI, compared to those with normal BMI, exhibited significantly higher compressive strains in the tibial cartilage. Cartilage thickness on both femoral condyles decreased significantly from the AM to the PM time point; however, there was no significant effect of BMI on diurnal cartilage strain in the femur. CONCLUSION Increased BMI is associated with increased diurnal strains in articular cartilage of both the medial and lateral compartments of the knee. The increased cartilage strains observed in individuals with high BMI may, in part, explain the elevated risk of OA associated with obesity or may reflect alterations in the cartilage mechanical properties in subjects with high BMI.
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Affiliation(s)
- Margaret R Widmyer
- Duke University and Duke University Medical Center, Durham, North Carolina
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Integrin α1β1 participates in chondrocyte transduction of osmotic stress. Biochem Biophys Res Commun 2014; 445:184-90. [PMID: 24495803 DOI: 10.1016/j.bbrc.2014.01.157] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 01/27/2014] [Indexed: 11/20/2022]
Abstract
BACKGROUND/PURPOSE The goal of this study was to determine the role of the collagen binding receptor integrin α1β1 in regulating osmotically induced [Ca(2+)]i transients in chondrocytes. METHOD The [Ca(2+)]i transient response of chondrocytes to osmotic stress was measured using real-time confocal microscopy. Chondrocytes from wildtype and integrin α1-null mice were imaged ex vivo (in the cartilage of intact murine femora) and in vitro (isolated from the matrix, attached to glass coverslips). Immunocytochemistry was performed to detect the presence of the osmosensor, transient receptor potential vanilloid-4 (TRPV4), and the agonist GSK1016790A (GSK101) was used to test for its functionality on chondrocytes from wildtype and integrin α1-null mice. RESULTS/INTERPRETATION Deletion of the integrin α1 subunit inhibited the ability of chondrocytes to respond to a hypo-osmotic stress with [Ca(2+)]i transients ex vivo and in vitro. The percentage of chondrocytes responding ex vivo was smaller than in vitro and of the cells that responded, more single [Ca(2+)]i transients were observed ex vivo compared to in vitro. Immunocytochemistry confirmed the presence of TRPV4 on wildtype and integrin α1-null chondrocytes, however application of GSK101 revealed that TRPV4 could be activated on wildtype but not integrin α1-null chondrocytes. Integrin α1β1 is a key participant in chondrocyte transduction of a hypo-osmotic stress. Furthermore, the mechanism by which integrin α1β1 influences osmotransduction is independent of matrix binding, but likely dependent on the chondrocyte osmosensor TRPV4.
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TRPV4-mediated mechanotransduction regulates the metabolic response of chondrocytes to dynamic loading. Proc Natl Acad Sci U S A 2014; 111:1316-21. [PMID: 24474754 DOI: 10.1073/pnas.1319569111] [Citation(s) in RCA: 309] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Mechanical loading of joints plays a critical role in maintaining the health and function of articular cartilage. The mechanism(s) of chondrocyte mechanotransduction are not fully understood, but could provide important insights into new physical or pharmacologic therapies for joint diseases. Transient receptor potential vanilloid 4 (TRPV4), a Ca(2+)-permeable osmomechano-TRP channel, is highly expressed in articular chondrocytes, and loss of TRPV4 function is associated with joint arthropathy and osteoarthritis. The goal of this study was to examine the hypothesis that TRPV4 transduces dynamic compressive loading in articular chondrocytes. We first confirmed the presence of physically induced, TRPV4-dependent intracellular Ca(2+) signaling in agarose-embedded chondrocytes, and then used this model system to study the role of TRPV4 in regulating the response of chondrocytes to dynamic compression. Inhibition of TRPV4 during dynamic loading prevented acute, mechanically mediated regulation of proanabolic and anticatabolic genes, and furthermore, blocked the loading-induced enhancement of matrix accumulation and mechanical properties. Furthermore, chemical activation of TRPV4 by the agonist GSK1016790A in the absence of mechanical loading similarly enhanced anabolic and suppressed catabolic gene expression, and potently increased matrix biosynthesis and construct mechanical properties. These findings support the hypothesis that TRPV4-mediated Ca(2+) signaling plays a central role in the transduction of mechanical signals to support cartilage extracellular matrix maintenance and joint health. Moreover, these insights raise the possibility of therapeutically targeting TRPV4-mediated mechanotransduction for the treatment of diseases such as osteoarthritis, as well as to enhance matrix formation and functional properties of tissue-engineered cartilage as an alternative to bioreactor-based mechanical stimulation.
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Irianto J, Swift J, Martins RP, McPhail GD, Knight MM, Discher DE, Lee DA. Osmotic challenge drives rapid and reversible chromatin condensation in chondrocytes. Biophys J 2013; 104:759-69. [PMID: 23442954 DOI: 10.1016/j.bpj.2013.01.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Revised: 08/20/2012] [Accepted: 01/07/2013] [Indexed: 02/02/2023] Open
Abstract
Changes in extracellular osmolality have been shown to alter gene expression patterns and metabolic activity of various cell types, including chondrocytes. However, mechanisms by which physiological or pathological changes in osmolality impact chondrocyte function remain unclear. Here we use quantitative image analysis, electron microscopy, and a DNase I assay to show that hyperosmotic conditions (>400 mOsm/kg) induce chromatin condensation, while hypoosmotic conditions (100 mOsm/kg) cause decondensation. Large density changes (p < 0.001) occur over a very narrow range of physiological osmolalities, which suggests that chondrocytes likely experience chromatin condensation and decondensation during a daily loading cycle. The effect of changes in osmolality on nuclear morphology (p < 0.01) and chromatin condensation (p < 0.001) also differed between chondrocytes in monolayer culture and three-dimensional agarose, suggesting a role for cell adhesion. The relationship between condensation and osmolality was accurately modeled by a polymer gel model which, along with the rapid nature of the chromatin condensation (<20 s), reveals the basic physicochemical nature of the process. Alterations in chromatin structure are expected to influence gene expression and thereby regulate chondrocyte activity in response to osmotic changes.
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Affiliation(s)
- Jerome Irianto
- Institute of Bioengineering, School of Engineering and Material Science, Queen Mary, University of London, London, United Kingdom.
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Abstract
Mechanical factors play a crucial role in the development of articular cartilage in vivo. In this regard, tissue engineers have sought to leverage native mechanotransduction pathways to enhance in vitro stem cell-based cartilage repair strategies. However, a thorough understanding of how individual mechanical factors influence stem cell fate is needed to predictably and effectively utilize this strategy of mechanically-induced chondrogenesis. This article summarizes some of the latest findings on mechanically stimulated chondrogenesis, highlighting several new areas of interest, such as the effects of mechanical stimulation on matrix maintenance and terminal differentiation, as well as the use of multifactorial bioreactors. Additionally, the roles of individual biophysical factors, such as hydrostatic or osmotic pressure, are examined in light of their potential to induce mesenchymal stem cell chondrogenesis. An improved understanding of biomechanically-driven tissue development and maturation of stem cell-based cartilage replacements will hopefully lead to the development of cell-based therapies for cartilage degeneration and disease.
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Guilak F. Biomechanical factors in osteoarthritis. Best Pract Res Clin Rheumatol 2013; 25:815-23. [PMID: 22265263 DOI: 10.1016/j.berh.2011.11.013] [Citation(s) in RCA: 353] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 11/24/2011] [Indexed: 12/20/2022]
Abstract
Biomechanical factors play an important role in the health of diarthrodial joints. Altered joint loading - associated to obesity, malalignment, trauma or joint instability - is a critical risk factor for joint degeneration, whereas exercise and weight loss have generally been shown to promote beneficial effects for osteoarthritic joints. The mechanisms by which mechanical stress alters the physiology or pathophysiology of articular cartilage or other joint tissues likely involve complex interactions with genetic and molecular influences, particularly local or systemic inflammation secondary to injury or obesity. Chondrocytes perceive physical signals from their environment using a variety of mechanisms, including ion channels, integrin-mediated connections to the extracellular matrix that involve membrane, cytoskeletal and intracellular deformation. An improved understanding of the biophysical and molecular pathways involved in chondrocyte mechanotransduction can provide insight into the development of novel therapeutic approaches for osteoarthritis.
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Affiliation(s)
- Farshid Guilak
- Departments of Orthopaedic Surgery and Biomedical Engineering, Duke University Medical Center, Durham, NC 27710, USA.
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Eleswarapu SV, Athanasiou KA. TRPV4 channel activation improves the tensile properties of self-assembled articular cartilage constructs. Acta Biomater 2013; 9:5554-61. [PMID: 23128162 DOI: 10.1016/j.actbio.2012.10.031] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Revised: 10/19/2012] [Accepted: 10/26/2012] [Indexed: 11/18/2022]
Abstract
A persistent hurdle in the field of tissue regeneration is to produce tissues with biochemical and biomechanical properties robust enough to meet the aggressive physiological demands of the native milieu. In an effort to improve these properties tissues grown in vitro are often subjected to mechanical stimuli that aim to recapitulate the in vivo physiology. These mechanical stimuli are thought to produce downstream alterations in intracellular ion concentrations, which ultimately give rise to increased biosynthesis. There is mounting evidence that these perturbations in the cellular microenvironment are regulated by the Ca(2+)-permeable transient receptor potential vanilloid 4 (TRPV4) channel. In this study we examined the effects of targeted TRPV4 activation on self-assembled articular cartilage constructs. The objectives of this study were: (i) to determine whether TRPV4 activation would enhance self-assembled constructs; (ii) to identify an optimal treatment time window for TRPV4 activation; and (iii) to compare TRPV4 activation which Na(+)/K(+) pump inhibition, which has previously been shown to improve the construct tensile properties. This study employed a two phase approach. In Phase I self-assembled constructs were grown for 4weeks and subjected to treatment with the TRPV4 agonist 4α-phorbol-12,13-didecanoate (4α-PDD) during three treatment time windows: t=6-10, t=10-14, and t=14-18days. Treatment for t=10-14days produced an 88% increase in collagen and a 153% increase in tensile stiffness. This treatment window was carried forward to Phase II. In Phase II we performed a head to head comparison between TRPV4 activation using 4α-PDD and Na(+)/K(+) pump inhibition using ouabain. Treatment with 4α-PDD produced improvements on a par with ouabain (91-107% increases in tensile stiffness). The results of this study demonstrate the effectiveness of ion channel modulation as a strategy for improving engineered tissues. To our knowledge this is the first study to examine TRPV4 channel activation in tissue engineering.
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Affiliation(s)
- Sriram V Eleswarapu
- Department of Biomedical Engineering, University of California, Davis, CA 95616, USA
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Chen J, Irianto J, Inamdar S, Pravincumar P, Lee DA, Bader DL, Knight MM. Cell mechanics, structure, and function are regulated by the stiffness of the three-dimensional microenvironment. Biophys J 2013; 103:1188-97. [PMID: 22995491 DOI: 10.1016/j.bpj.2012.07.054] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 07/06/2012] [Accepted: 07/27/2012] [Indexed: 11/17/2022] Open
Abstract
This study adopts a combined computational and experimental approach to determine the mechanical, structural, and metabolic properties of isolated chondrocytes cultured within three-dimensional hydrogels. A series of linear elastic and hyperelastic finite-element models demonstrated that chondrocytes cultured for 24 h in gels for which the relaxation modulus is <5 kPa exhibit a cellular Young's modulus of ∼5 kPa. This is notably greater than that reported for isolated chondrocytes in suspension. The increase in cell modulus occurs over a 24-h period and is associated with an increase in the organization of the cortical actin cytoskeleton, which is known to regulate cell mechanics. However, there was a reduction in chromatin condensation, suggesting that changes in the nucleus mechanics may not be involved. Comparison of cells in 1% and 3% agarose showed that cells in the stiffer gels rapidly develop a higher Young's modulus of ∼20 kPa, sixfold greater than that observed in the softer gels. This was associated with higher levels of actin organization and chromatin condensation, but only after 24 h in culture. Further studies revealed that cells in stiffer gels synthesize less extracellular matrix over a 28-day culture period. Hence, this study demonstrates that the properties of the three-dimensional microenvironment regulate the mechanical, structural, and metabolic properties of living cells.
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Affiliation(s)
- J Chen
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
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Diurnal variations in articular cartilage thickness and strain in the human knee. J Biomech 2012; 46:541-7. [PMID: 23102493 DOI: 10.1016/j.jbiomech.2012.09.013] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 09/26/2012] [Accepted: 09/28/2012] [Indexed: 11/21/2022]
Abstract
Due to the biphasic viscoelastic nature of cartilage, joint loading may result in deformations that require times on the order of hours to fully recover. Thus, cartilaginous tissues may exhibit cumulative strain over the course of each day. The goal of this study was to assess the magnitude and spatial distribution of strain in the articular cartilage of the knee with daily activity. Magnetic resonance (MR) images of 10 asymptomatic subjects (six males and four females) with mean age of 29 years were obtained at 8:00 AM and 4:00 PM on the same day using a 3T magnet. These images were used to create 3D models of the femur, tibia, and patella from which cartilage thickness distributions were quantified. Cartilage thickness generally decreased from AM to PM in all areas except the patellofemoral groove and was associated with significant compressive strains in the medial condyle and tibial plateau. From AM to PM, cartilage of the medial tibial plateau exhibited a compressive strain of -5.1±1.0% (mean±SEM) averaged over all locations, while strains in the lateral plateau were slightly lower (-3.1±0.6%). Femoral cartilage showed an average strain of -1.9±0.6%. The findings of this study show that human knee cartilage undergoes diurnal changes in strain that vary with site in the joint. Since abnormal joint loading can be detrimental to cartilage homeostasis, these data provide a baseline for future studies investigating the effects of altered biomechanics on diurnal cartilage strains and cartilage physiology.
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Influence of cell culture configuration on the post-cryopreservation viability of primary rat hepatocytes. Biomaterials 2012; 33:829-36. [DOI: 10.1016/j.biomaterials.2011.10.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 10/10/2011] [Indexed: 02/08/2023]
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Felipe-Pérez YE, Valencia J, Juárez-Mosqueda MDL, Pescador N, Roa-Espitia AL, Hernández-González EO. Cytoskeletal proteins F-actin and β-dystrobrevin are altered by the cryopreservation process in bull sperm. Cryobiology 2011; 64:103-9. [PMID: 22209823 DOI: 10.1016/j.cryobiol.2011.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 12/16/2011] [Accepted: 12/19/2011] [Indexed: 10/14/2022]
Abstract
The cryopreservation process has an important impact on sperm structure and physiology. The negative effects have been mainly observed on the plasma membrane, which is directly stabilized by the cytoskeleton. Since cytoskeleton proteins are osmosensitive and thermosensitive, the aim of this study was to evaluate the damage caused to the bull sperm cytoskeleton by cryopreservation (freezing-thawing). Fresh and frozen-thawed bull semen samples were exposed to a treatment with the neutral detergent Brij 36-T. Electron microscopy evidenced important damages at the sperm perinuclear theca after the protein extraction protocol; the perinuclear theca was partially solubilized, the perinuclear theca substructure disappeared in the cryopreserved samples. Furthermore, the sperm head's shape was significantly altered on the cryopreserved samples. Fluorescence analysis showed a decrease of the intensity of actin and dystrobrevin on the frozen-thawed samples. Western blot assays revealed a stronger signal for actin and β-dystrobrevin in the frozen-thawed sperm samples than in the fresh ones. Our results suggest that the cryopreservation process highly alters the sperm cytoskeleton stability, causing its proteins to become more fragile and therefore more susceptible to be extracted.
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Lewis R, Feetham CH, Barrett-Jolley R. Cell volume regulation in chondrocytes. Cell Physiol Biochem 2011; 28:1111-22. [PMID: 22179000 DOI: 10.1159/000335847] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/05/2011] [Indexed: 11/19/2022] Open
Abstract
Chondrocytes are the cells within cartilage which produce and maintain the extracellular matrix. Volume regulation in these cells is vital to their function and occurs in several different physiological and pathological contexts. Firstly, chondrocytes exist within an environment of changing osmolarity and compressive loads. Secondly, in osteoarthritic joint failure, cartilage water content changes and there is a notable increase in chondrocyte apoptosis. Thirdly, endochondral ossification requires chondrocyte swelling in association with hypertrophy. Regulatory volume decrease (RVD) and regulatory volume increase (RVI) have both been observed in articular chondrocytes and this review focuses on the mechanisms identified to account for these. There has been evidence so far to suggest TRPV4 is central to RVD; however other elements of the pathway have not yet been identified. Unlike RVD, RVI appears less robust in articular chondrocytes and there have been fewer mechanistic studies; the primary focus being on the Na(+)-K(+)-2Cl(-) co-transporter. The clinical significance of chondrocyte volume regulation remains unproven. Importantly however, transcript abundances of several ion channels implicated in volume control are changed in chondrocytes from osteoarthritic cartilage. A critical question is whether disturbances of volume regulation mechanisms lead to, result from or are simply coincidental to cartilage damage.
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Affiliation(s)
- Rebecca Lewis
- Department of Musculoskeletal Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
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Osmotic stress alters chromatin condensation and nucleocytoplasmic transport. Biochem Biophys Res Commun 2011; 408:230-5. [PMID: 21463604 DOI: 10.1016/j.bbrc.2011.03.131] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 03/30/2011] [Indexed: 11/22/2022]
Abstract
Osmotic stress is a potent regulator of biological function in many cell types, but its mechanism of action is only partially understood. In this study, we examined whether changes in extracellular osmolality can alter chromatin condensation and the rate of nucleocytoplasmic transport, as potential mechanisms by which osmotic stress can act. Transport of 10 kDa dextran was measured both within and between the nucleus and the cytoplasm using two different photobleaching methods. A mathematical model was developed to describe fluorescence recovery via nucleocytoplasmic transport. As osmolality increased, the diffusion coefficient of dextran decreased in the cytoplasm, but not the nucleus. Hyper-osmotic stress decreased nuclear size and increased nuclear lacunarity, indicating that while the nucleus was getting smaller, the pores and channels interdigitating the chromatin had expanded. The rate of nucleocytoplasmic transport was increased under hyper-osmotic stress but was insensitive to hypo-osmotic stress, consistent with the nonlinear osmotic properties of the nucleus. The mechanism of this osmotic sensitivity appears to be a change in the size and geometry of the nucleus, resulting in a shorter effective diffusion distance for the nucleus. These results may explain physical mechanisms by which osmotic stress can influence intracellular signaling pathways that rely on nucleocytoplasmic transport.
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Clark AL, Votta BJ, Kumar S, Liedtke W, Guilak F. Chondroprotective role of the osmotically sensitive ion channel transient receptor potential vanilloid 4: age- and sex-dependent progression of osteoarthritis in Trpv4-deficient mice. ACTA ACUST UNITED AC 2010; 62:2973-83. [PMID: 20583100 DOI: 10.1002/art.27624] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Mechanical loading significantly influences the physiology and pathology of articular cartilage, although the mechanisms of mechanical signal transduction are not fully understood. Transient receptor potential vanilloid 4 (TRPV4) is a Ca(++)-permeable ion channel that is highly expressed by articular chondrocytes and can be gated by osmotic and mechanical stimuli. The goal of this study was to determine the role of Trpv4 in the structure of the mouse knee joint and to determine whether Trpv4(-/-) mice exhibit altered Ca(++) signaling in response to osmotic challenge. METHODS Knee joints of Trpv4(-/-) mice were examined histologically and by microfocal computed tomography for osteoarthritic changes and bone structure at ages 4, 6, 9, and 12 months. Fluorescence imaging was used to quantify chondrocytic Ca(++) signaling within intact femoral cartilage in response to osmotic stimuli. RESULTS Deletion of Trpv4 resulted in severe osteoarthritic changes, including cartilage fibrillation, eburnation, and loss of proteoglycans, that were dependent on age and male sex. Subchondral bone volume and calcified meniscal volume were greatly increased, again in male mice. Chondrocytes from Trpv4(+/+) mice demonstrated significant Ca(++) responses to hypo-osmotic stress but not to hyperosmotic stress. The response to hypo-osmotic stress or to the TRPV4 agonist 4α-phorbol 12,13-didecanoate was eliminated in Trpv4(-/-) mice. CONCLUSION Deletion of Trpv4 leads to a lack of osmotically induced Ca(++) signaling in articular chondrocytes, accompanied by progressive, sex-dependent increases in bone density and osteoarthritic joint degeneration. These findings suggest a critical role for TRPV4-mediated Ca(++) signaling in the maintenance of joint health and normal skeletal structure.
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Raizman I, De Croos JNA, Pilliar R, Kandel RA. Calcium regulates cyclic compression-induced early changes in chondrocytes during in vitro cartilage tissue formation. Cell Calcium 2010; 48:232-42. [PMID: 20932575 DOI: 10.1016/j.ceca.2010.09.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 09/07/2010] [Accepted: 09/08/2010] [Indexed: 11/18/2022]
Abstract
A single application of cyclic compression (1kPa, 1Hz, 30min) to bioengineered cartilage results in improved tissue formation through sequential catabolic and anabolic changes mediated via cell shape changes that are regulated by α5β1 integrin and membrane-type metalloprotease (MT1-MMP). To determine if calcium was involved in this process, the role of calcium in regulating cell shape changes, MT1-MMP expression and integrin activity in response to mechanical stimulation was examined. Stimulation-induced changes in cell shape and MT1-MMP expression were abolished by chelation of extracellular calcium, and this effect was reversed by re-introduction of calcium. Spreading was inhibited by blocking stretch-activated channels (with gadolinium), while retraction was prevented by blocking the L-Type voltage-gated channel (with nifedipine); both compounds inhibited MT1-MMP upregulation. Calcium A23187 ionophore restored cellular response further supporting a role for these channels. Calcium regulated the integrin-mediated signalling pathway, which was facilitated through Src kinase. Both calcium- and integrin-mediated pathways converged on ERK-MAPK in response to stimulation. While both integrins and calcium signalling mediate chondrocyte mechanotransduction, calcium appears to play the major regulatory role. Understanding the underlying molecular mechanisms involved in chondrocyte mechanotransduction may lead to the development of improved bioengineered cartilage.
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Affiliation(s)
- Igal Raizman
- CIHR-BioEngineering of Skeletal Tissue Team, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada M5G 1X5
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Guilak F, Leddy HA, Liedtke W. Transient receptor potential vanilloid 4: The sixth sense of the musculoskeletal system? Ann N Y Acad Sci 2010; 1192:404-9. [PMID: 20392266 DOI: 10.1111/j.1749-6632.2010.05389.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The critical discovery in the past two decades of the transient receptor potential (TRP) superfamily of ion channels has revealed the potential mechanisms by which cells sense diverse stimuli beyond the prototypical "five senses," identifying ion channels that are gated by heat, cold, mechanical loading, osmolarity, and other physical and chemical stimuli. TRP vanilloid 4 (TRPV4) is a Ca(2+)-permeable nonselective cation channel that appears to play a mechanosensory or osmosensory role in several musculoskeletal tissues. In articular cartilage, TRPV4 exhibits osmotic sensitivity, controlling cellular volume recovery, and other physiologic responses to osmotic stress. TRPV4 is expressed in both osteoblasts and osteoclasts, and the absence of TRPV4 prevents disuse-induced bone loss. TRPV4 activation promotes chondrogenesis by inducing SOX9 transcription, whereas a TRPV4 gain-of-function mutation leads to a developmental skeletal dysplasia, suggesting a critical role for TRPV4 in skeletal development. These studies provide mounting evidence for a regulatory role for the sensory channel TRPV4 in control of musculoskeletal tissues.
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Affiliation(s)
- Farshid Guilak
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA.
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White R, Gibson JS. The effect of oxygen tension on calcium homeostasis in bovine articular chondrocytes. J Orthop Surg Res 2010; 5:27. [PMID: 20420658 PMCID: PMC2873548 DOI: 10.1186/1749-799x-5-27] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 04/26/2010] [Indexed: 01/11/2023] Open
Abstract
Background Articular chondrocytes normally experience a lower O2 tension compared to that seen by many other tissues. This level may fall further in joint disease. Ionic homeostasis is essential for chondrocyte function but, at least in the case of H+ ions, it is sensitive to changes in O2 levels. Ca2+ homeostasis is also critical but the effect of changes in O2 tension has not been investigated on this parameter. Here we define the effect of hypoxia on Ca2+ homeostasis in bovine articular chondrocytes. Methods Chondrocytes from articular cartilage slices were isolated enzymatically using collagenase. Cytoplasmic Ca2+ levels ([Ca2+]i) were followed fluorimetrically using Fura-2 to determine the effect of changes in O2 tension. The effects of ion substitution (replacing extracellular Na+ with NMDG+ and chelating Ca2+ with EGTA) were tested. Levels of reactive oxygen species (ROS) and the mitochondrial membrane potential were measured and correlated with [Ca2+]i. Results A reduction in O2 tension from 20% to 1% for 16-18 h caused [Ca2+]i to approximately double, reaching 105 ± 23 nM (p < 0.001). Ion substitutions indicated that Na+/Ca2+ exchange activity was not inhibited at low O2 levels. At 1% O2, ROS levels fell and mitochondria depolarised. Restoring ROS levels (with an oxidant H2O2, a non-specific ROS generator Co2+ or the mitochondrial complex II inhibitor antimycin A) concomitantly reduced [Ca2+]i. Conclusions O2 tension exerts a significant effect on [Ca2+]i. The proposed mechanism involves ROS from mitochondria. Findings emphasise the importance of using realistic O2 tensions when studying the physiology and pathology of articular cartilage and the potential interactions between O2, ROS and Ca2+.
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Affiliation(s)
- Rachel White
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 OES, UK.
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Haudenschild DR, Nguyen B, Chen J, D'Lima DD, Lotz MK. Rho kinase-dependent CCL20 induced by dynamic compression of human chondrocytes. ACTA ACUST UNITED AC 2010; 58:2735-42. [PMID: 18759278 DOI: 10.1002/art.23797] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
OBJECTIVE Mechanical stimulation of cartilage affects tissue homeostasis and chondrocyte function. The chondrocyte phenotype is dependent on cell shape, which is largely determined by the actin cytoskeleton. Reorganization of the actin cytoskeleton results from Rho GTPase activation. The purpose of this study was to examine the roles of both actin and Rho in mechanotransduction in chondrocytes. METHODS We embedded human articular chondrocytes in 2 x 6-mm agarose discs at 5 x 10(6) cells/ml and subjected the discs to unconfined dynamic compression at 0.5 Hz. By comparing samples with and without dynamic compression, we identified Rho activation according to the GTP-bound active RhoA measured in cell lysates. We identified rearrangements in filamentous actin structures using fluorescence-labeled phalloidin and confocal microscopy of fixed samples. We identified altered gene expression using TaqMan quantitative reverse transcription-polymerase chain reaction analysis. We tested for a requirement for Rho signaling by performing the dynamic compression in the presence of Rho kinase inhibitors. RESULTS RhoA activation occurred within 5-10 minutes of dynamic compression. Rho kinase-dependent actin reorganization occurred within 20 minutes after application of dynamic compression and was apparent as "punctate" F-actin structures that were visible under confocal microscopy. We identified early-phase mechanoresponsive genes (CCL20 and inducible nitric oxide synthase) that were highly up-regulated within 1 hour of dynamic compression in a Rho kinase-dependent and actin-dependent manner. CONCLUSION Together, these results are the first demonstration that the Rho-Rho kinase pathway and actin cytoskeletal reorganization are required for changes in the expression of genes involved in human chondrocyte mechanotransduction.
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Horvat-Gordon M, Praul C, Ramachandran R, Bartell P, Leach, R. Use of microarray analysis to study gene expression in the avian epiphyseal growth plate. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2010; 5:12-23. [DOI: 10.1016/j.cbd.2009.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Revised: 08/31/2009] [Accepted: 08/31/2009] [Indexed: 12/15/2022]
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Finan JD, Guilak F. The effects of osmotic stress on the structure and function of the cell nucleus. J Cell Biochem 2010; 109:460-7. [PMID: 20024954 PMCID: PMC3616882 DOI: 10.1002/jcb.22437] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Osmotic stress is a potent regulator of the normal function of cells that are exposed to osmotically active environments under physiologic or pathologic conditions. The ability of cells to alter gene expression and metabolic activity in response to changes in the osmotic environment provides an additional regulatory mechanism for a diverse array of tissues and organs in the human body. In addition to the activation of various osmotically- or volume-activated ion channels, osmotic stress may also act on the genome via a direct biophysical pathway. Changes in extracellular osmolality alter cell volume, and therefore, the concentration of intracellular macromolecules. In turn, intracellular macromolecule concentration is a key physical parameter affecting the spatial organization and pressurization of the nucleus. Hyper-osmotic stress shrinks the nucleus and causes it to assume a convoluted shape, whereas hypo-osmotic stress swells the nucleus to a size that is limited by stretch of the nuclear lamina and induces a smooth, round shape of the nucleus. These behaviors are consistent with a model of the nucleus as a charged core/shell structure pressurized by uneven partition of macromolecules between the nucleoplasm and the cytoplasm. These osmotically-induced alterations in the internal structure and arrangement of chromatin, as well as potential changes in the nuclear membrane and pores are hypothesized to influence gene transcription and/or nucleocytoplasmic transport. A further understanding of the biophysical and biochemical mechanisms involved in these processes would have important ramifications for a range of fields including differentiation, migration, mechanotransduction, DNA repair, and tumorigenesis.
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Affiliation(s)
- John D Finan
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
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