Chronic inflammation is a principal cause of atherosclerosis and other vascular diseases. Inflammation is an orchestrated response to trauma incited by tissue injury or microbial invasion of the host. The inflammatory response is initiated by cytokines that induce cascades of signaling events culminating in the expression of new gene products, some of them toxic to invading organisms. Uncontrolled production or accumulation of inflammatory products can be injurious to the host organism. Mechanisms have evolved that limit the production of these products and permit resolution of the inflammatory response. The central hypothesis of this continuing Program Project is that pro- and anti-inflammatory processes in vascular cells are tightly regulated by endogenous signaling pathways, and their dysregulation contributes to vascular diseases such as atherosclerosis. We will investigate this hypothesis through three highly focused, but well-integrated projects led by a team of accomplished experts in diverse areas of vascular inflammation. In Project 1, Dr. Xiaoxia Li investigates the macrophage signaling pathways initiated by the interleukin-1R (IL-1 receptor)/TLR (Toll-like receptor) superfamily which can lead to either a pro-inflammatory, transcriptional program of gene expression, or an anti-inflammatory, post-transcriptional program. The theme of pro- and anti-inflammation, and also post-transcriptional regulation, continues in Project 2, led by Dr. Paul Fox, which focuses on a distinct post-transcriptional mechanism in monocyte/macrophages in which interferon-??induces phosphorylation- dependent formation of a complex that binds select inflammatory transcripts and inhibits their translation. The goal of Project 3, led by Dr. Paul DiCorleto, is to understand the role of the tumor necrosis factor receptor p75 and the transcription factor HOXA9 in the transcriptional regulation of pro-inflammatory genes in endothelial cells. Three scientific cores (Cell Culture, Atherosclerosis and Lipoprotein Analysis, and Macromolecular Interaction) and an Administration Core will provide multi-project support, expertise, and service in a cost-effective manner, which will significantly strengthen each investigator's research effort.