Gasdermin D serves as a key executioner of pyroptosis in experimental cerebral ischemia and reperfusion model both in vivo and in vitro

Abstract

Even though ischemic stroke is among the leading causes of death worldwide, the pathogenic mechanisms underlying ischemia reperfusion (I/R) brain injury remain unclear. Gasdermin D (GSDMD), as an important factor of pyroptotic death execution downstream of caspase-11 (noncanonical inflammasome) and caspase-1 (canonical inflammasome), may be implicated in I/R injury. The current study aimed to investigate the role and possible underlying mechanisms of GSDMD in pyroptosis during I/R injury. Results indicated that the nucleotide-binding oligomerization domain-like receptors (NLR family) pyrin domain containing 3 (NLRP3) inflammasomes were assembled and activated after middle cerebral artery occlusion/reperfusion (MCAO/R), leading to increased levels of IL-1β and IL-18. Additionally, GSDMD levels were elevated, and its N-terminal fragment (GSDMD-N) was cleaved to induce pyroptosis after MCAO/R, which was partly dependent on caspase-1 activation and its Asp280 amino acid site. Furthermore, it was found that GSDMD-N could bind to membrane lipids and exhibit membrane-disrupting cytotoxicity, depending on its Glu15 and Leu156 amino acid sites. Nevertheless, the C-terminal fragment of gasdermin (GSDMD-C) exhibited an auto-inhibitory effect on GSDMD-N-induced pyroptosis via binding to GSDMD in the cytoplasm. Taken together, this information suggests that GSDMD may participate in caspase-1-mediated pyroptosis during I/R injury both in vivo and in vitro, which could be a potential therapeutic target to reduce brain I/R injury.