Quercetin Alleviates Cerebral Ischemia-Induced Neuroinflammation by Inhibiting Microglia-Mediated NLRP3/Caspase-1/GSDMD Pathway

TL;DR

Quercetin reduces brain inflammation after ischemia by blocking a key pathway involving microglia and the NLRP3 protein.

Contribution

This study provides direct molecular evidence that quercetin inhibits the NLRP3/Caspase-1/GSDMD pyroptosis axis in cerebral ischemia.

Findings

Quercetin ameliorates OGD-induced injury in BV2 microglia and reduces pyroptosis and inflammation markers.

Quercetin relieves motor dysfunction and cortical injury in PT mice by inhibiting the pyroptosis axis.

Molecular simulations show quercetin binds to the NACHT domain of NLRP3, stabilizing the complex via van der Waals interactions.

Abstract

In the pathological cascade of cerebral ischemia, the pyroptosis axis mediated by the NLRP3 inflammasome in activated microglia is a core link driving neuroinflammation and secondary brain injury. Quercetin has been proven to possess multi-target neuroprotective activity, and its anti-inflammatory effect has attracted particular attention. However, direct molecular evidence is lacking regarding how quercetin precisely regulates the NLRP3/Caspase-1/GSDMD core pyroptosis axis in microglia in cerebral ischemia models and whether it can directly target NLRP3 to inhibit this axis, thereby alleviating cerebral ischemic injury. This study aimed to investigate the molecular mechanism by which quercetin alleviates cerebral ischemic injury through inhibiting the pyroptosis axis, combining cellular and animal models with molecular docking and molecular dynamics simulations. The oxygen-glucose deprivation (OGD) model of BV2 microglia and the photothrombotic (PT) model of focal cortical ischemia in male C57BL/6 mice were used to detect the ameliorative effect of quercetin on cerebral ischemia-related injury through cellular and animal experiments. AutoDock Vina 1.5.7 and GROMACS 2025.3 software were employed for molecular docking and molecular dynamics simulations, respectively, to analyze the binding mode and complex stability between quercetin and the NLRP3 protein. The results showed that quercetin could significantly ameliorate OGD-induced injury in BV2 cells and downregulate the expression of pyroptosis and inflammation-related proteins and factors. Meanwhile, it relieved motor dysfunction in PT mice, attenuated cortical neuronal injury, and inhibited the activation of the cerebral pyroptosis axis. At the molecular level, molecular simulation predictions indicated that quercetin might specifically bind to the NACHT domain of the NLRP3 protein, forming a complex with a stable conformation, and van der Waals interactions served as the main driving force for binding. This study confirmed that quercetin can directly bind to the NLRP3 protein and alleviate cerebral ischemia-induced inflammatory injury by inhibiting the activation of the NLRP3/Caspase-1/GSDMD pyroptosis axis and the release of downstream inflammatory factors. Combined with the molecular simulation results, a predictive hypothesis is proposed: direct binding of quercetin to the NLRP3 protein is one of its core mechanisms of action. These findings provide direct experimental evidence for the development of NLRP3-based drugs against ischemic brain injury.

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