DESCRIPTION (provided by applicant): Though the role of genes in heart disease is appreciated, there is currently little understanding of the mechanism by which the transcription factor NF-kB contributes to the antithetical processes of cardioprotection and ischemia/reperfusion (I/R) injury. This Critical Gap In Knowledge prevents the successful development of therapies employing NF-kB inhibition or cytokine blockade in cardiovascular disease. The objective of the proposal is to fill this knowledge gap; to develop a comprehensive understanding of the mechanism by which NF-kB and NF-kB-dependent gene expression networks affect I/R injury, cardioprotection, post-I/R dysfunction and heart failure. We offer the central hypothesis that NF-kB mediates differential responses to different stimuli by regulating distinct sets of NF-kB-dependent genes. We propose three specific aims; 1) Delineate the sets of NF-kB-dependent genes that underlie the antithetical effects of NF-kB upon cell death after I/R and PO, 2) Determine the transcriptional mechanism by which NF-kB modulates gene expression to evoke cell death after I/R and cell survival after PO, 3) Determine the biological effects and therapeutic potential of PGAA polyplexes during acute and chronic post-ischemic disease in vivo. The approach is to employ an hypothesis-driven microarray strategy that takes advantage of our IkBDN mice (block NF-kB) to delineate NF-kB-dependent genes functionally associated with NF-kB-dependent pro-injury and cardioprotective effects. We will also employ an innovative non-viral polymeric nucleic acid delivery technology (PGAA) to block NF-kB activation (decoys) and to silence NF-kB-dependent genes (siRNA) in vivo. We expect that the results will provide a mechanistic understanding of how NF-kB-dependent genes underlie differential responses in the heart. Public Health Relevance: The proposed research is significant because it will lead to identification of new therapeutic targets and development of novel therapies for ischemic heart disease. The proposal develops a novel and innovative set of reagents for basic science that can be used for DNA and siRNA delivery in vivo. The proposal is highly translational in that it develops the therapeutic use of PGAA-mediated decoy and siRNA delivery in pre- clinical studies.