Taz/Wnt-Beta-Catenin/C-Myc Axis Regulates Cystogenesis In Polycystic Kidney Disease

Autosomal-dominant polycystic kidney disease (ADPKD) is the most common genetic renal disease, primarily caused by germline mutation of PKD1 or PKD2, leading to end-stage renal disease. The Hippo signaling pathway regulates organ growth and cell prolif-eration. Herein, we demonstrate the regulatory mechanism of cystogenesis in ADPKD by transcriptional coactivator with PDZ-binding motif (TAZ), a Hippo signaling effector. TAZ was highly expressed around the renal cyst-lining epithelial cells of Pkd1-deficient mice. Loss of Taz in Pkd1-deficient mice reduced cyst formation. In wild type, TAZ interacted with PKD1, which inactivated beta-catenin. In contrast, in PKD1-deficient cells, TAZ interacted with AXIN1, thus increasing beta-catenin activity. Interaction of TAZ with AXIN1 in PKD1-deficient cells resulted in nuclear accumulation of TAZ together with beta-catenin, which up-regulated c-MYC expression. Our findings suggest that the PKD1-TAZ-Wnt-beta-catenin-c-MYC signaling axis plays a critical role in cystogenesis and might be a potential therapeutic target against ADPKD.