Hypo-osmotic stress induces calcium-dependent actin reorganization in articular chondrocytes

G. R. Erickson, D. L. Northrup, Farshid Guilak

Research output: Contribution to journalArticle

69 Scopus citations

Abstract

Objective: The aim of this study was to investigate the effects of hypo-osmotically induced calcium (Ca2+) transients on the organization of the actin cytoskeleton in articular chondrocytes. The secondary hypothesis tested was that actin restructuring following hypo-osmotic stress is mediated by gelsolin. Methods: Isolated porcine chondrocytes were exposed to hypo-osmotic stress, and [Ca2+]i was monitored using laser scanning microscopy. Calcium transients were monitored using fluorescent ratiometric imaging. The intracellular distribution of actin was examined using fluorescent immunohistochemistry and transient transfection with the pEGFP-actin plasmid. The intracellular distribution of gelsolin was investigated using fluorescent immunohistochemistry. Results: Osmotic stress induced transient increases in [Ca2+]i caused reorganization of intracellular actin through a mechanism that required Ca2+ in the extracellular media. Fluorescence microscopy revealed that gelsolin was colocalized with F-actin immediately following hypo-osmotic stress but dissociated over time. Conclusion: These results indicate that hypo-osmotic stress induces a gelsolin-mediated reorganization of actin through a transient increase in [Ca2+]i.

Original languageEnglish
Pages (from-to)187-197
Number of pages11
JournalOsteoarthritis and Cartilage
Volume11
Issue number3
DOIs
StatePublished - Mar 1 2003
Externally publishedYes

Keywords

  • Ca
  • Cartilage
  • Chondrocyte
  • F-actin
  • Gelsolin
  • Inositol triphosphate
  • Osmotic
  • Osteoarthritis

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