Protocatechuic Acid Protects Neural Stem Cells against Cerebral Ischemia-Reperfusion Injury by Suppressing JAK2/STAT3 Signaling and Restoring Mitophagy.

Background

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Objectives

Neural stem cells (NSCs) are important for endogenous brain repair but are highly vulnerable to mitochondrial dysfunction during cerebral ischemia-reperfusion injury (CIRI). Preliminary bioinformatics analysis suggested that immune microenvironment remodeling and JAK/STAT signaling activation are involved in CIRI pathology. This study investigated whether protocatechuic acid (PCA) protects NSCs after ischemia-reperfusion injury and explored the underlying mechanisms focusing on the JAK2/STAT3 pathway and mitophagy.

Results

Bioinformatics analysis identified JAK/STAT signaling as a potential regulatory node in CIRI. Transcriptome sequencing further showed that PCA markedly altered the gene expression profile of NSCs, with differentially expressed genes enriched in the JAK/STAT pathway. In vitro, PCA suppressed OGD/R-induced JAK2/STAT3 activation, restored mitochondrial membrane potential, reduced DCFH-DA and MitoSOX Red oxidation-sensitive fluorescence signals, promoted TOMM20/LC3 colocalization, enhanced PINK1/Parkin-related mitophagy, and improved NSC survival. Co-treatment with the JAK2 inhibitor AG490 further supported the protective and pro-mitophagic effects of PCA, whereas co-treatment with the JAK/STAT pathway activator RO8191 weakened PCA-mediated mitochondrial protection and mitophagy restoration. In vivo, PCA improved neurological function, reduced infarct volume, attenuated hippocampal neuronal injury, preserved endogenous NSCs and NeuN-positive cells, and enhanced mitophagy-related signals in MCAO/R rats. Importantly, in vivo Western blot analysis showed that PCA suppressed MCAO/R-induced JAK2/STAT3 phosphorylation, whereas RO8191 co-treatment attenuated this inhibitory effect and weakened the protective effects of PCA, supporting the involvement of JAK2/STAT3 inhibition in PCA-mediated neuroprotection.

Conclusion

PCA alleviates CIRI and protects NSCs partly by suppressing JAK2/STAT3 activation, restoring mitochondrial function, and promoting PINK1/Parkin-mediated mitophagy. These findings provide experimental evidence supporting mitochondrial quality control and NSC protection as potential therapeutic targets for ischemic stroke.