TAZ/Wnt-β-catenin/c-MYC axis regulates cystogenesis in polycystic kidney disease

Abstract

Autosomal-dominant polycystic kidney disease (ADPKD) is the most common genetic renal disease, primarily caused by germline mutation of <i>PKD1</i> or <i>PKD2</i>, leading to end-stage renal disease. The Hippo signaling pathway regulates organ growth and cell proliferation. 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 <i>Pkd1</i>-deficient mice. Loss of <i>Taz</i> in <i>Pkd1</i>-deficient mice reduced cyst formation. In wild type, TAZ interacted with PKD1, which inactivated β-catenin. In contrast, in PKD1-deficient cells, TAZ interacted with AXIN1, thus increasing β-catenin activity. Interaction of TAZ with AXIN1 in PKD1-deficient cells resulted in nuclear accumulation of TAZ together with β-catenin, which up-regulated c-MYC expression. Our findings suggest that the PKD1-TAZ-Wnt-β-catenin-c-MYC signaling axis plays a critical role in cystogenesis and might be a potential therapeutic target against ADPKD.