Integrin beta 4 is involved in apoptotic signal transduction in endothelial cells

To clarify the signal transduction in vascular endothelial cells (VEC) apoptosis induced by deprivation of FGF and serum, we investigated the function of integrin beta 4 by using the monoclonal antibody (mAb) of this integrin. We added anti-beta 4 integrin mAb at the concentration of 5 mu g/ml to the cells deprived of FGF and serum, apoptosis of these cells were completely inhibited 24 h after the treatment. Furthermore we plated the cells onto untreated bacterial culture plates on which the cells cannot adhere and spread in MCDB medium without FGF and serum; however, when antip 4 integrin mAb was present at 5 mu g/ml in the seeding medium, the cells rapidly adhered and spread. Our results first demonstrated that integrin beta 4 participated in apoptotic signaling in VEC, and our findings indicate that hemidesmosome structures and keratin filament system might be important in regulation of apoptotic signaling. (C) 1997 Academic Press.