Echinocystic acid alleviates cerebral ischemia-reperfusion injury through PPARγ-dependent modulation of microglial polarization and pyroptotic signaling.

Abstract

Cerebral ischemia-reperfusion injury (CIRI) worsens outcomes after ischemic stroke, yet effective pharmacological interventions remain limited. Echinocystic acid (EA), a pentacyclic triterpenoid isolated from the fruits of Gleditsia sinensis Lam., has shown neuroprotective activity in CIRI, but its direct molecular target and underlying mechanism remain unclear. In this study, using network pharmacology, molecular docking, surface plasmon resonance, and subsequent validation in middle cerebral artery occlusion (MCAO) mice and oxygen-glucose deprivation/reoxygenation (OGD/R)-treated BV2 cells, we identified peroxisome proliferator-activated receptor γ (PPARγ) as a potential target of EA and provided evidence supporting direct binding between EA and PPARγ. EA significantly reduced infarct volume and brain edema while improving neurological outcomes in MCAO mice, and also attenuated OGD/R-induced injury in BV2 cells. Mechanistically, EA restored PPARγ expression, promoted microglial M2 polarization, reduced IL-1β, IL-6, and TNF-α levels, increased IL-10 production, and attenuated NLRP3/Caspase-1/GSDMD-associated pyroptotic signaling in both in vivo and in vitro models. These effects were largely reversed by the PPARγ antagonist GW9662. Collectively, these findings indicate that EA protects against CIRI, at least in part, through a PPARγ-dependent mechanism involving promotion of microglial M2 polarization and attenuation of NLRP3/Caspase-1/GSDMD-associated pyroptotic signaling, highlighting the therapeutic potential of EA in CIRI.