Cascade-Type Microglial Pyroptosis Inhibitors for Enhanced Treatment of Cerebral Ischemia-Reperfusion Injury

Neuroinflammation is a critical factor in the progression of cerebral ischemia-reperfusion injury (CIRI). Pyroptosis, which is an inflammatory form of programmed cell death, greatly amplifies neuroinflammatory processes. It does so by promoting the release of various inflammatory contents that intensify the overall inflammatory response within the central nervous system. Therefore, targeting pyroptosis represents a promising therapeutic strategy for the treatment of CIRI. Excessive generation of reactive oxygen species (ROS) by overactivated microglia is considered to serve as the signal molecule that triggers NLRP3 inflammasome-mediated pyroptosis. However, current pyroptosis inhibitors that solely focus on eliminating existing ROS or inhibiting the NLRP3 inflammasome are not optimal. Here, by coating nanothylakoids (NTs) coengineered with fibrin-binding peptide and MG1 peptide onto dihydrotanshinone I (DT)-loaded nanocarriers, we have developed a cascade-type pyroptosis inhibitor (MDN-MC) that comprehensively regulates the ROS/NLRP3/pyroptosis axis. The incorporation of catalase on the surface of MDN-MC, along with the release of DT, facilitated cascade inhibition of pyroptosis by scavenging existing ROS and suppressing the expression of NLRP3. In the rat model of transient middle cerebral artery occlusion, enhanced behavioral recovery and facilitated neuronal repair were achieved through cascade targeting of inflammatory microglia at the lesion site and implementation of interventions to inhibit pyroptosis, thereby demonstrating promising therapeutic effects. Overall, this work emphasizes the importance of cascade-regulated pyroptosis in reducing neuroinflammation, offering an important mechanistic understanding and possible therapeutic approaches for CIRI.