ASC in Renal Collecting Duct Epithelial Cells Contributes to Inflammation and Injury after Unilateral Ureteral Obstruction

Inflammation plays a crucial role in the pathophysiologicat characteristics of chronic kidney disease; however, the inflammatory mechanisms underlying the chronic kidney disease process remain unclear. Recent evidence indicates that sterile inflammation triggered by tissue injury is mediated through a muttiprotein complex called the inflammasome. Therefore, we investigated the role of the inflammasome in the development of chronic kidney disease using a murine unilateral ureteral obstruction (UUO) model. Inflammasome-related molecules were up-regulated in the kidney after UUO. Apoptosis-associated speck-like protein containing a caspase recruitment domain deficiency significantly reduced inflammatory responses, such as inflammatory cell infiltration and cytokine expression, and improved subsequent renal injury and fibrosis. Furthermore, apoptosis-associated speck-like protein containing a caspase recruitment domain was specifically up-regulated in collecting duct (CD) epithelial cells of the UUO-treated kidney. In vitro experiments showed that extracellular adenosine triphosphate (ATP) induced inflammasome activation in CD epithelial cells through P2X(7)-potassium efflux and reactive oxygen species dependent pathways. These results demonstrate the molecular basis for the inflammatory response in the process of chronic kidney disease and suggest the CD inflammasome as a potential therapeutic target for preventing chronic kidney disease progression.