Immune Cell and Epithelial Cell Interactions in Autosomal Dominant Polycystic Kidney Disease

PROJECT SUMMARY Autosomal dominant polycystic kidney disease (ADPKD) is the most common, potentially lethal, monogenic disease. Affecting 1:400 to 1:1000 people, mutations in PKD1 and PKD2 genes encoding polycystin-1 (PC1) and polycystin-2, respectively, lead to development of fluid-filled cysts that progressively expand from renal epithelial cells. This expansion damages surrounding kidney tissue, causing fibrosis, and leads to worsening kidney function that ultimately requires dialysis or transplant. Half of the ADPKD population will experience renal failure by the age of 50, and there are few treatment options to prevent such pathogenesis. These preventative solutions are lacking due to limited understanding into the process of cystogenesis, meaning why cysts form and what makes them worsen over time. Immune cells may contribute to this process. Prior literature has suggested a role for macrophages in cyst initiation and expansion, and CD8+ T cells have recently emerged as exerting a potential anti-cystogenic role. Using a novel transgenic suppression model of ADPKD in which a portion of the C-terminal tail of PC1 is expressed, I will compare the immune cell populations present in a non-suppressed disease model and the suppression model with non-cystic controls. I hypothesize that the differential immune cell landscapes between disease models will reveal pro-cystogenic and anti-cystogenic factors that regulate renal epithelial cells in ADPKD pathogenesis. With the expertise in ADPKD from the Caplan Lab and in immunological investigation from the Craft Lab, I will investigate the role of immune cells in ADPKD pathogenesis in murine models using in vivo interventional strategies, and analyze these models by flow cytometry, immunofluorescence, and single-cell sequencing approaches. I seek to define immune cell signaling in ADPKD and to elucidate the implications of this signaling for ADPKD pathogenesis, expecting to identify immune- mediated factors implicated in cystogenesis. In addition to elucidating cellular signaling that modifies the cystic and fibrotic manifestations of ADPKD, this proposal simultaneously aims to identify immune cell properties that could serve as disease biomarkers and provide insight into treatment and monitoring strategies.