Signal transduction of β2m-induced expression of VCAM-1 and COX-2 in synovial fibroblasts

Neal X. Chen, Kalisha D. O’Neill, Toshimitsu Niwa, Sharon M. Moe

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

Background. β2 microglobulin (β2m) amyloidosis is a destructive articular disease affecting dialysis patients. We have demonstrated that β2m increases the expression of vascular cell adhesion molecule (VCAM-1) and cyclooxygenase-2 (COX-2) in human osteoarthritic synovial fibroblasts (SFLs). Methods. To determine the cell signaling pathways, SFLs were incubated with β2m in the presence or absence of various inhibitors for 24 hours. Intracellular calcium ([Ca2+]i) was measured by fluorometric techniques and vascular cell adhesion molecule-1 (VCAM-1) and cyclooxygenase-2 (COX-2) expression was determined by immunohistochemistry and Western blotting. Results. β2 increased [Ca2+]i levels in a dose dependent manner (P < 0.05) in SFLs. BAPTA-AM, a [Ca2+]i chelator, completely inhibited β2m-induced expression of VCAM-1 and COX-2. U73122 [phospholipase C (PLC) inhibitor] or 2-APB [specific inhibitor of inositol 1,4,5-trisphosphate (IP3)-induced [Ca2+]i release] completely blocked the β2m-induced increase in [Ca2+]i and the up-regulation of VCAM-1 and COX-2. However, pretreatment with staurosporin, a protein kinase C inhibitor, had no effect. Disruption of the actin cytoskeleton by treatment with cytochalasin D or latrunculin A blocked β2m up-regulation of VCAM-1 and COX-2. Finally, cells treated with phosphatidylinositol-3 kinase (PI-3 kinase) inhibitors wortmannin or LY294002 also failed to express VCAM-1 and COX-2. Conclusions. These results demonstrate that IP3-mediated [Ca2+]i release, PI-3 kinase, and actin cytoskeleton reorganizatio are involved in β2m-induced expression of VCAM-1 and COX-2 in human SFLs. Understanding the potential pathways by which β2m exerts its inflammatory-like effects may lead to the development of future therapies.

Original languageEnglish (US)
Pages (from-to)414-424
Number of pages11
JournalKidney international
Volume61
Issue number2
DOIs
StatePublished - Jan 1 2002

Keywords

  • Actin cytoskeleton
  • Articular disease
  • Cell signaling
  • Gene expression
  • Intracellular calcium
  • Phosphatidylinositol-3 kinase

ASJC Scopus subject areas

  • Nephrology

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