PARP-1 is a Negative Modulator of the Heart Shock Response

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DESCRIPTION (provided by applicant): I am a junior faculty member in the Department of Critical Care Medicine at the University of Pittsburgh. I am trained in Pediatric Critical Care Medicine and I recently completed a T-32 training grant at Cincinnati Children's Hospital. My short-term goal is to acquire additional training in molecular biology and learn additional techniques relevant to my long term goal: conduct translational research related to the biology of sepsis to improve outcomes for critically ill children. With the guidance of my mentor Dr. Mitchell P. Fink, (Chairman of my department at University of Pittsburgh) and key co-mentors, I have developed a program of formal coursework and tutorials that will form the educational and training core necessary to achieve my goals. My research project "Poly (ADP-ribose) polymerase (PARP) -1 is a negative modulator of the heat shock response" is designed to both provide vital new information and serve as an educational opportunity that compliments the other components of my career development plan. PARP-1 is a nuclear enzyme that upon activation mediates progression of septic shock. Genetic deletion or pharmacological inhibition of PARP is protective in animal models of sepsis. Another major cytoprotective stress response that is upregulated in critical care illness is the heat shock response (HSR). My preliminary data suggests that PARP-1 inhibition or genetic absence of PARP-1 is associated with upregulation of the HSR. DNA binding by the main transcription factor responsible for the HSR, heat shock factor (HSF)-1 in wild type (wt) cells is increased when heat-shocked cells are pretreated with a PARP-1 inhibitor (DIQ). Heat shocked PARP-/- cells demonstrate abundant HSP-70 expression and HSP-70 promoter activity, hallmarks of the HSR. However, DNA binding of HSF-1 in heat-shocked PARP-1-/- cells is not detectable by electrophoretic mobility shift assay (EMSA). Some of the experiments outlined in the present proposal should shed some light on this paradox (i.e. increased transcription of a HSF-1-dependent gene but absent HSF-1 DNA binding in heat shocked PARP-1-/- cells). Thus, in Aim 1,1 will confirm the data obtained in PARP-/- cells by studying wt cells transfected with small interfering RNA (siRNA) directed against PARP-1. Aim 2 examines the effect of PARP-1 inhibition on HSF-1-mediated transactivation. Aim 3 seeks to study these phenomena in an in vivo setting, specifically examining the effects of heat shock in wt and PARP-/- animals.