Cytokine induced expression of porcine inhibitor of apoptosis protein (iap) family member is regulated by NF-(κ)B

The inhibitor of apoptosis (iap) proteins belong to a gene family that protect certain cell to undergo programmed cell death in response to a variety of stimuli. By differential screening we have identified a cDNA clone, designated piap, in porcine aortic endothelial cells (PAEC) that turned out by sequence comparison to be a porcine member of the lap family, The expression of piap is strongly up-regulated upon treatment of endothelial cells (EC) with inflammatory cytokines TNF-α, IL-1β, and LPS. In EC these stimuli lead to the activation of nuclear transcription factor kappa B (NF-κB) that plays a role in countering TNF-α induced apoptosis. We demonstrate that adenovirus mediated overexpression of IκBα, an inhibitor of NF-κB suppresses the expression of piap in response to TNF-α suggesting that piap is one of the NF-κB regulated genes that operates to prevent programmed cell death of EC in inflammation.