Abnormal purinergic signaling contributes to development of renal cysts in autosomal dominant polycystic kidney disease

Polycystic kidney diseases (PKD) are a group of inherited nephropathies marked by the formation of fluid-filled cysts along the nephron, which cause renal failure. Bulk RNA sequencing of microdissected renal cysts from Pkd1RC/ RC mice identifies 4,970 differentially expressed genes in comparison to intact collecting ducts. A poorly understood factor of cyst growth is the high ATP level in the cyst fluid, probably released by pannexin-1 hemichannels. Here, we evaluate a novel pannexin-1 inhibitor SIL14 as a potential therapeutic agent for cyst reduction and investigate proteins involved in cystogenesis, with a focus on purinergic signaling. In patch-clamp experiments, acute SIL14 application demonstrated strong, dose-dependent inhibition of Pannexin-1-dependent currents ( IC50 = 12.96 μM). Chronic treatment of renal collecting duct cells with 30 μM SIL14 significantly reduced cyst size in a Matrigel model of cyst formation. Notably, RNA sequencing reveals that purinergic receptors P2Y2 and P2Y4, normally expressed in collecting ducts, were downregulated, while P2X5, P2X7, P2Y6, and P2Y12 were upregulated in the cystic epithelium. Stimulation with α,βMe-ATP or Bz-ATP (P2X7 agonists) increased cyst size and pannexin-1 expression in Matrigel cultures. Our findings indicate that the transition of normal collecting ducts to cystic epithelium is accompanied by distorted purinergic signaling and propose inhibition of luminal ATP release via pannexin- 1 is a potential method to limit cystogenesis.