AdipoRon alleviates cerebral ischemic injury through AMPK-dependent microglial autophagy and phenotypic modulation

Ischemic stroke is a leading cause of death and disability with limited therapeutic options. Neuroinflammation, particularly microglial activation and phenotypic modulation, plays a crucial role in ischemic cerebral injury. AdipoRon (APR), an adiponectin receptor agonist, shows neuroprotective effects, but its role in modulating microglial phenotypic states after ischemic stroke remains unclear. Using a transient middle cerebral artery occlusion (tMCAO) model, we demonstrated that APR treatment significantly ameliorated neurological deficits caused by ischemic injury. Our findings revealed that APR markedly reduced CD16 expression while enhancing CD206 expression in microglia, suggesting its neuroprotective actions are closely associated with microglial phenotypic modulation. We further explored APR effects on autophagy, given its crucial role in regulating microglial phenotypic states. APR significantly enhanced autophagy, and this enhancement was partially reversed by 3-methyladenine (3-MA), concomitantly reversing APR-induced CD206-associated microglial phenotype and its anti-inflammatory effects. To delineate the underlying mechanism, we examined adiponectin receptor signaling and downstream AMPK pathway involvement. Using siRNA-mediated knockdown of AdipoR1 and AMPK inhibitor Compound C, we observed marked reduction in autophagy levels and impairment of APR regulatory effects on microglial phenotypic modulation and inflammation. Collectively, our findings indicate that AdipoRon alleviates ischemic cerebral injury by activating the AdipoR1-AMPK signaling pathway, which subsequently enhances autophagy to promote a microglial phenotypic shift characterized by decreased CD16 and increased CD206 expression. These findings provide novel insights into APR neuroprotective mechanisms and highlight its potential as a therapeutic agent for ischemic stroke.