Novel Approaches to Identifying and Targeting Sepsis-Associated Endothelial Dysfunction

PROJECT SUMMARY/ABSTRACT: The career development award will support Hilary Faust, MD, MTR, in becoming an independent physician- investigator focused on identifying mechanisms of sepsis-associated endothelial dysfunction. Sepsis causes >300,000 deaths a year in the US, predominantly due to sepsis-associated organ failure. Endothelial dysfunction is a major contributor to organ failure in sepsis, but difficulty accessing human endothelial tissue and preclinical models that incompletely replicate sepsis heterogeneity hinder development of clinically available diagnostic tools and targeted therapies. Dr. Faust has developed 2 complementary approaches to model human sepsis-associated endothelial dysfunction and test candidate therapies without risk to critically ill patients. Her endothelial microphysiological system (MPS) replicates sepsis plasma-associated endothelial dysfunction, while capture of circulating endothelial cells (CECs) from sepsis patients allows direct study of endothelial sepsis responses. To maximize insights from these approaches, Dr. Faust has set two career development goals: (1) master advanced human endothelial injury techniques using MPS and CEC capture and (2) gain transcriptomic expertise to identify novel endothelial dysfunction mechanisms. Dr. Faust will pursue these objectives through a 5-year career development plan involving structured didactics, experiential research, and intensive mentoring. Dr. Faust will be mentored by Dr. Lynn M. Schnapp MD, a physician- scientist with expertise in basic science investigations of lung injury and repair, with an outstanding record of mentorship and co-mentor Dr. Nuala J. Meyer, MD MTR, an expert in molecular phenotyping of sepsis patients who has mentored Dr. Faust for >6 years. Dr. Faust's career development will be supported by the exceptional institutional environment of the University of Wisconsin and strong research infrastructure of the Schnapp Laboratory and the team of mentors and collaborators. These skills will allow Dr. Faust to expand her research focus from her previous work identifying the association of mitochondrial DNA (mtDNA) with sepsis-associated organ failure to explore endothelial mtDNA signaling via Toll-like Receptor 9 (TLR9). By testing inhibition of TLR9 in the endothelial MPS, she will define the potential of this promising candidate pathway as a therapeutic target for sepsis-associated organ failure (Specific Aim 1a). She will also use the MPS to identify 1b) novel mechanisms of sepsis plasma-induced endothelial dysfunction using RNAseq. In Aim 2, she will capture CECs cells and perform the first detailed phenotyping of CECs in human sepsis through imaging flow cytometry and RNAseq. This will provide previously inaccessible insight into endothelial sepsis responses and determine whether CECs can serve as a noninvasive surrogate for evaluating endothelial injury. Ultimately, the career development activities and support of the NIGMS K08 will enable Dr. Faust to become a leading translational sepsis investigator committed to identifying effective, direly needed targeted therapies for sepsis patients.