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Extracellular and Intracellular Mechanisms of Mechanotransduction in Three-Dimensionally Embedded Rat Chondrocytes
PURPOSE: Articular cartilage homeostasis involves modulation of chondrocyte matrix synthesis in response to mechanical stress (MS). We studied extracellular and intracellular mechanotransduction pathways mediating this response. METHODS: We first confirmed rapid up-regulation of the putative chondro...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4257595/ https://www.ncbi.nlm.nih.gov/pubmed/25479057 http://dx.doi.org/10.1371/journal.pone.0114327 |
Sumario: | PURPOSE: Articular cartilage homeostasis involves modulation of chondrocyte matrix synthesis in response to mechanical stress (MS). We studied extracellular and intracellular mechanotransduction pathways mediating this response. METHODS: We first confirmed rapid up-regulation of the putative chondro-protective cytokine, interleukin (IL)-4, as an immediate response to MS. We then studied the role of IL-4 by investigating responses to exogenous IL-4 or a specific IL-4 inhibitor, combined with MS. Next we investigated the intracellular second messengers. Since chondrocyte phenotype alters according to the extracellular environment, we characterized the response to mechanotransduction in 3-dimensionally embedded chondrocytes. RESULTS: Expression of aggrecan and type II collagen was significantly up-regulated by exogenous IL-4 whereas MS-induced matrix synthesis was inhibited by an IL-4 blocker. Further, MS-induced matrix synthesis was completely blocked by a p38 MAPK inhibitor, while it was only partially blocked by inhibitors of other putative second messengers. CONCLUSION: IL-4 mediates an extracellular pathway of mechanotransduction, perhaps via an autocrine/paracrine loop, while p38 mediates an intracellular pathway prevalent only in a 3-dimensional environment. |
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