Andrographolide attenuates microglial senescence in Alzheimer's disease mice by suppressing the STAT3 signaling

Andrographolide (AP), a diterpenoid extracted from Andrographis paniculata, has emerged as a promising treatment for Alzheimer's disease (AD) in preclinical studies, but the underlying mechanisms remain incompletely defined. Here, we demonstrated that AP treatment improved cognition performance and reduced amyloid-β (Aβ) plaque accumulation in 5×FAD transgenic mice of both sexes, by mitigating microglial senescence. Proteomic analysis revealed that AP markedly decreased cholesterol content in the cerebral cortex. Using an in vitro low-density lipoprotein-induced senescence model, we found that AP significantly alleviated senescence in BV2 microglia while enhancing their phagocytic capacity. Mechanistically, AP mitigated microglial senescence by inhibiting STAT3 signaling. Overall, these findings identify a previously unrecognized immunometabolic mechanism for AP in the treatment of AD.