Mechanisms of metformin in alleviating neurological deficits in stroke patients: Involving Ndufa11-mediated mitochondrial protection, enhanced neuronal electrophysiology, and inhibition of disulfidptosis

Ischemic stroke (IS) remains a leading global cause of disability and mortality, with limited therapeutic options beyond the narrow time window of recanalization. There is a pressing clinical need for neuroprotective agents that can be administered beyond this window to directly preserve neuronal function.Metformin (MET), a widely used antidiabetic drug with a favorable safety profile, has shown neuroprotective potential in observational studies. However, its precise mechanisms, particularly concerning the recovery of neuronal electrophysiological function and its interaction with newly identified cell death pathways like disulfidptosis, are unclear, hindering its repurposing for stroke therapy. This study aims to bridge this critical knowledge gap. A retrospective analysis of 865 IS patients with type 2 diabetes revealed that MET use was independently associated with milder neurological deficits (assessed by NIHSS scores) across acute, convalescent, and sequela stages. In vitro, using an oxygen-glucose deprivation/reperfusion (OGD/R) model in primary cortical neurons, MET pretreatment significantly enhanced neuronal survival. Crucially, patch-clamp recordings revealed that MET restored action potential amplitude, thereby identifying the restoration of electrophysiological function as a novel neuroprotective mechanism. Mechanistically, MET upregulated the mitochondrial complex I subunit Ndufa11, enhanced its interaction with Ndufs1, and increased the abundance of the Ndufs1-Ndufa11 complex. Furthermore, MET significantly suppressed key markers of disulfidptosis, including xCT expression, the NADP⁺/NADPH ratio, and cystine uptake. Lentivirus-mediated overexpression of Ndufa11 replicated all the protective effects of MET, including enhanced complex formation, improved survival, restored action potential amplitude, and suppression of disulfidptosis. In conclusion, our findings demonstrate that MET protects against ischemic injury by enhancing mitochondrial function via the Ndufs1-Ndufa11 axis and concurrently inhibiting disulfidptosis. This work not only identifies Ndufa11 as a key mediator of MET's effects but also provides a compelling mechanistic rationale for repositioning MET as a multifaceted therapeutic strategy for ischemic stroke.