A direct requirement of nuclear factor-kappa B for suppression of apoptosis in ventricular myocytes

Faculty of Medicine, Department of Physiology, Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, University of Manitoba, Winnipeg, Manitoba, Canada R2H 2A6 Nuclear factor- B (NF- B) is a ubiquitously expressed cellular factor regulated by the cytoplasmic factor inhibitor protein B (I B ). Activation of NF- B by cytokines, including tumor necrosis factor- (TNF- ), requires the phosphorylation and degradation of I B . An anti-apoptotic role for NF- B has recently been suggested. In the present study, we ascertained whether death-promoting signals and apoptosis mediated by TNF- are suppressed by NF- B in postnatal ventricular myocytes. Stimulation of myocytes with TNF- resulted in a 12.1-fold increase ( P