Epithelial Vasopressin Type-2 Receptors Regulate Myofibroblasts by a YAP-CCN2–Dependent Mechanism in Polycystic Kidney Disease

Significance Statement In autosomal dominant polycystic kidney disease (ADPKD), progressive fibrosis contributes to renal failure, leading to ESKD. The vasopressin type-2 receptor (V2R) helps to regulate renal water homeostasis and stimulates cyst expansion in ADPKD. We discovered a novel pathogenic pathway behind V2R regulation of fibrosis in ADPKD kidneys. Epithelial V2R stimulation activates interstitial myofibroblasts, in a paracrine manner, in Pkd1 gene knockout (KO) mice. Pharmacologic inhibition and gene knockout studies indicated that V2R regulates myofibroblast activation by a yes-associated protein (YAP)– and connective tissue growth factor (CCN2)–dependent mechanism. The V2R-YAP-CCN2 molecular axis may present novel pharmacologic targets for control of fibrosis in ADPKD. Background Fibrosis is a major cause of loss of renal function in autosomal dominant polycystic kidney disease (ADPKD). In this study, we examined whether vasopressin type-2 receptor (V2R) activity in cystic epithelial cells can stimulate interstitial myofibroblasts and fibrosis in ADPKD kidneys. Methods We treated Pkd1 gene knockout ( Pkd1 KO) mice with dDAVP, a V2R agonist, for 3 days and evaluated the effect on myofibroblast deposition of extracellular matrix (ECM). We also analyzed the effects of conditioned media from primary cultures of human ADPKD cystic epithelial cells on myofibroblast activation. Because secretion of the profibrotic connective tissue growth factor (CCN2) increased significantly in dDAVP-treated Pkd1 KO mouse kidneys, we examined its role in V2R-dependent fibrosis in ADPKD as well as that of yes-associated protein (YAP). Results V2R stimulation using dDAVP increased the renal interstitial myofibroblast population and ECM deposition. Similarly, conditioned media from human ADPKD cystic epithelial cells increased myofibroblast activation in vitro , suggesting a paracrine mechanism. Renal collecting duct–specific gene deletion of CCN2 significantly reduced cyst growth and myofibroblasts in Pkd1 KO mouse kidneys. We found that YAP regulates CCN2 , and YAP inhibition or gene deletion reduces renal fibrosis in Pkd1 KO mouse kidneys. Importantly, YAP inactivation blocks the dDAVP-induced increase in myofibroblasts in Pkd1 KO kidneys. Further in vitro studies showed that V2R regulates YAP by an ERK1/2-dependent mechanism in human ADPKD cystic epithelial cells. Conclusions Our results demonstrate a novel mechanism by which cystic epithelial cells stimulate myofibroblasts in the pericystic microenvironment, leading to fibrosis in ADPKD. The V2R-YAP-CCN2 cell signaling pathway may present a potential therapeutic target for fibrosis in ADPKD.