<scp>HIF</scp> ‐Regulated Pannexin‐1 Channel Drives Luminal <scp>ATP</scp> Accumulation in Kidney Cysts

Autosomal dominant polycystic kidney disease (ADPKD) is marked by the progressive development of bilateral kidney cysts, leading to compression of intact surrounding tissue and a subsequent decline in kidney function. Accumulation of ATP within the cyst fluid significantly drives cyst expansion by activating purinergic receptors, thereby promoting calcium-dependent chloride secretion. Moreover, the induction of hypoxia-inducible factor 1α (HIF-1α) in cyst-lining epithelial cells further enhances chloride conductance. However, the mechanisms underlying ATP release into the cyst fluid and the role of HIF-1α in cyst enlargement remain incompletely understood. Here, we demonstrate that the ATP-release channel Pannexin-1 is regulated by HIF-1α in kidney tubular cells, leading to its prominent localization at the apical membrane of kidney cysts in both human and murine ADPKD kidney tissue. Apical ATP release is elevated in PKD1-deficient cyst-forming cells following pharmacological induction of HIF-1α and attenuated by two Pannexin-1 inhibitors, Probenecid and Brilliant Blue FCF (BB-FCF). HIF-dependent cyst growth in vitro is inhibited by basolateral application of the cell-permeable Probenecid, whereas the cell-impermeable BB-FCF requires luminal application to exert its effect. In conclusion, HIF-1α promotes Pannexin-1 expression in cyst-lining cells, facilitating directional ATP release into the cyst lumen and driving ATP-dependent cyst expansion.