Polycystin-1 (PC1), encoded by the PKD1 gene, is a large transmembrane glycoprotein that orchestrates critical cellular processes—including cell–cell and cell–matrix interactions, calcium signaling, and mechanosensation—in renal tubular epithelial cells. PC1 regulates various aspects of cellular function, including signal transduction, cytoskeletal remodeling, and cell adhesion. It forms a functional complex with Polycystin-2 (PC2), the product of the PKD2 gene, to maintain intracellular calcium homeostasis and facilitate mechanotransduction ^[1]. Disruption of PC1 signaling, due to PKD1 mutations—which account for approximately 85% of autosomal dominant polycystic kidney disease (ADPKD) cases—undermines these regulatory pathways, promoting abnormal cell proliferation and cyst formation ^[2]. Clinically, ADPKD is characterized by the progressive development of multiple fluid-filled cysts, renal enlargement, hypertension, and eventual progression to end-stage kidney disease (ESKD). With a global incidence estimated at 1 in 400 to 1 in 1000 individuals, ADPKD affects nearly 500,000 people in the United States alone and frequently involves extra-renal manifestations, including the heart, liver, pancreas, spleen, and arachnoid membrane ^[3]. Notably, genotypic heterogeneity exists, with PKD1 mutations often associated with an earlier onset and more aggressive disease course ^[2-3].

Traditional systemic Pkd1 knockout models are typically embryonically lethal, precluding long-term pathogenesis studies. In contrast, inducible, kidney-specific conditional knockout models using the Cre-LoxP system recapitulate the clinical features of human ADPKD and permit the investigation of disease progression in adult mice ^[4-5]. Chronic-PKD mice are an inducible conditional Pkd1 knockout model generated by crossing Pkd1-flox mice with kidney-specific, tamoxifen-inducible Cre mice (Cdh16-MerCreMer mice). Preliminary data show that palpable renal enlargement occurs at 6 weeks after tamoxifen induction. At 10 weeks post-induction, a polycystic kidney phenotype is visible upon dissection, with no mortality observed and a more pronounced phenotype in male mice. We will continue monitoring this model to characterize late-stage phenotypes and the overall disease progression.