HSPA8 lactylation attenuates neuronal pyroptosis via E3 ligase-mediated NLRP3 degradation after ischemic stroke

Pyroptosis contributes significantly to neuronal death following ischemic stroke. This study investigated whether lactylation of heat shock protein family A member 8 (HSPA8) modulates neuronal pyroptosis after ischemic/reperfusion injury.

Both in vitro oxygen-glucose deprivation/reperfusion (OGD/R) models and in vivo transient middle cerebral artery occlusion (tMCAO) mouse models were established to assess the functional significance of HSPA8 lactylation at lysine 524 (K524).

HSPA8 expression and lactylation increased following ischemic/reperfusion injury both in vitro and in vivo. K524 was the predominant lactylation site, regulated by p300 acetyltransferase and histone deacetylases. The lactylation-mimetic K524Q mutant significantly reduced pyroptosis markers (NLRP3, GSDMD, cleaved caspase-1) and pyroptotic cell death compared to wild-type or K524R mutant. In tMCAO mice, neuronal expression of HSPA8-K524Q reduced infarct volume and suppressed pyroptosis more effectively than K524R. Mechanistically, HSPA8 lactylation at K524 enhanced its interaction with the E3 ubiquitin ligases PARK2 and ARIH2, promoting NLRP3 ubiquitination and degradation.

HSPA8 lactylation at K524 is a critical regulator of neuronal pyroptosis and ischemic brain injury. This modification facilitates E3 ligase-mediated NLRP3 degradation and suppression of inflammasome activation. Targeting protein lactylation pathways may offer a promising therapeutic strategy for neuroprotection in ischemic stroke.