Inflammation, a hallmark of atherosclerosis and other vascular diseases, is characterized by the activation of several genes including cytokines, adhesion molecules, cyclooxygenases, and nitric oxide synthase. The long term goal of these studies is to identify the critical determinants required for the initiation and propagation of vascular inflammation. Our approach to unraveling the molecular mechanisms underlying vascular inflammation is to identify the transcription factors that regulate these responses. The NF-kappa B family of transcription factors are known to be critical mediators of these events. We have identified a novel Ets transcription factor ESE- 1, that is induced in response to interleukin- 1 beta, tumor necrosis factor alpha, and endotoxin in vascular smooth muscle cells, endothelial cells and monocytes. This induction is at least in part mediated by NF-kappa B. ESE-1 is unique among Ets factors in that it has two DNA binding domains, a classical Ets domain and an A/T hook domain found in HMG proteins. Our results demonstrate that both DNA binding domains of ESE-1 can bind to the p50 subunit of NF-kappa B. We have identified the inducible form of nitric oxide synthase (NOS2) as a target for ESE-l. ESE-1 is a strong transactivator of the NOS2 gene promoter and introduction of ESE-1 into cells can activate NOS2 gene expression. In a rat model of endotoxemia associated with acute vascular inflammation, ESE- 1 is strongly induced in vascular smooth muscle cells and endothelial cells. The hypothesis for these studies is that the Ets factor ESE-1 is a transcriptional mediator of vascular inflammation.
The specific aims of the study are to: I. Define the biological role of ESE-1 as a transcriptional activator of the NOS2 gene and other genes associated with vascular inflammation. II. Determine the DNA binding specificity and the functional importance of the two ESE-1 DNA binding domains. III. Determine the biological effect of ESE-1 expression on vascular cell function. The methods and models used to achieve these goals include electrophoretic mobility shift assays, immunohistochemistry, transcriptional profiling, animal models of vascular inflammation, and transgenic models. The results of these studies should provide new insights into the molecular mechanisms involved in regulating vascular inflammation and provide potential new therapeutic avenues for treatment of vascular diseases such as atherosclerosis, restenosis, and the vasculopathy associated with transplantation.
