P2RX7 and triple-A syndrome: Previously, another study reported that Pannexin-1 (Panx1) on vascular endothelial cells, a channel that releases ATP, stimulated macrophage activation by activating P2X7 receptor and mitochondrial DNA (mtDNA) release to increase the secretion of IL-1β as well as high-mobility group protein B1 (HMGB1, a notable late-stage inflammatory mediator), followed by promoting the formation of AAA [47].