ABSTRACT Background Mitochondrial dysfunction is an initial event of the cascade reactions triggered by ischemic stroke, contributing to the pathogenesis of ischemic brain injury. DL ‐3‐n‐butylphthalide ( NBP ), a compound originally isolated from the seeds of Apium graveolens Linn, exerts neuroprotective effects by improving mitochondrial function in ischemic brain tissues; however, the exact molecular mechanisms underlying its action remain poorly understood. Methods The OGD ‐exposed neuronal cells and dMCAO mice were used to investigate the effects of ischemia/hypoxia on mitochondrial function and the protective action of NBP on mitochondrial damage. Co‐immunoprecipitation and immunofluorescence staining were performed to identify the interaction between Drp1 and GCN5L1 . Western blotting, immunofluorescence and immunohistochemical staining were conducted to detect the expression of GCN5L1 , Drp1, ERK1 /2, Bax, Bcl2, and caspase‐3. The mitochondrial function was analyzed by measuring mitochondrial ROS , ATP production, mitochondrial membrane potential ( MMP ) and mPTP opening. Results We observed that mitochondrial dysfunction occurs in OGD ‐treated neuronal cells and brain tissues of dMCAO mice, as evidenced by the alteration in the mPTP , MMP , ATP content, and ROS levels, which are accompanied by a significant increase in mitochondrial fission and neuronal apoptosis, as shown by TUNEL staining and the changes in Bcl‐2, Bax and caspase‐3 expression. Importantly, NBP intervention significantly attenuates ischemia/hypoxia‐induced mitochondrial dysfunction and cellular apoptosis in the neuron and mouse brains. Mechanistically, NBP not only reverses the upregulation of Drp1 and GCN5L1 expression by ischemia/hypoxia, but also inhibits the ischemia/hypoxia‐induced phosphorylation of Drp1 by blocking the ERK1 /2 signaling, which in turn suppresses the interaction between Drp1 and GCN5L1 , thereby decreasing Drp1 acetylation by GCN5L1 and excessive mitochondrial fission. Conclusion Our findings provide a novel insight into the molecular mechanism whereby NBP protects mitochondria against ischemia/hypoxia damage, offering a promising drug for mitochondria‐targeting therapeutics for ischemic stroke.
Zhang et al. (Sun,) studied this question.