Regulation of IFN-beta induction by P2X7 purinergic receptor signaling

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DESCRIPTION (provided by applicant): Goals: My long-term research goal is to gain a greater understanding of the regulation of type I IFN production by macrophages, cells that are key players in inflammation. As a physician-scientist, it is my hope that these studies will eventually contribute to the improved treatment of inflammatory and autoimmune conditions. My immediate career goal is to develop a viable independent research program. Research project: During inflammation, the occurrence of tissue damage leads to sufficient release of extracellular purine nucleotides to stimulate immune cells via purinergic receptors such as P2X7. Stimulation of P2X7 by ATP is well known to increase the production of inflammatory cytokines (e.g. IL-1¿) by macrophages stimulated with endotoxin (LPS). We have found that co-stimulation of macrophages with LPS and the ATP analogue BzATP greatly augments the induction of IFN- ¿ by LPS. Type I IFNs play important roles in diverse aspects of innate and adaptive immunity. As both IFN- ¿ and purinergic receptor signaling have been implicated in bacterial sepsis and bone morphogenesis, it is critical to understand the mechanism of how P2X7 modulates the induction of IFN- ¿. To begin dissecting the mechanism of how P2X7 exerts its effect, a multi-pronged approach is proposed: We will examine the effect of P2X7 ligation on IFN- ¿ induction by different infectious stimuli (e.g. LPS, dsRNA etc.) to determine whether P2X7 enhancement is LPS specific. P2X7 ligation is known to initiate multiple signal transduction pathways: the contribution of calcium and MAP-kinase signaling pathways to the effect of BzATP on IFN- ¿ induction will be analyzed. Finally, we will examine the recruitment of transcription factors to the IFN- ¿ gene promoter by chromatin immunoprecipitation to test our underlying hypothesis that P2X7 ligation leads to increased transcription factor occupancy of the ifnb1 promoter. Modification of transcription factor recruitment by P2X7 mediated signaling has ramifications for the enhancement of immune responses and bone biology. Career development plan: The two key components are close collaboration with Paul Bertics and more formal oversight by a mentoring committee. Paul Bertics has abundant expertise in my area of interest and an excellent track record in training junior faculty. In addition to Dr. Bertics, my committee is composed of three other very supportive and successful physician scientists. Research environment: Through the department of Pediatrics, I have been accorded lab space, protected time and initial start-up funds. The breadth of expertise present at the University of Wisconsin, through the Medical and Graduate schools, is tremendous. Any equipment or technical assistance I should require will be available. There are ample forums for intellectual exchange as well as continuing education in the clinical and basic sciences. RELEVANCE: Macrophages participate in many inflammatory processes including responses to infections and autoimmune diseases by secreting cytokines. My research proposes to study how substances that are released by tissue damage called "purines" regulate the production of the inflammatory cytokine IFN- ¿ by macrophages. Greater understanding of inflammatory processes may ultimately lead to the better treatment of disease.