# Mitophagy Activation via the YAP/Parkin Pathway Underlies the Neuroprotective Action of Tetramethylpyrazine in Cerebral Ischemia/Reperfusion Injury

## TL;DR

Tetramethylpyrazine protects the brain from injury by boosting mitophagy through the YAP/Parkin pathway.

## Contribution

This study reveals a novel mechanism by which tetramethylpyrazine activates mitophagy via the YAP/Parkin pathway to protect against brain injury.

## Key findings

- Tetramethylpyrazine reduces infarct volume and improves neurological outcomes in mice with cerebral ischemia/reperfusion injury.
- Tetramethylpyrazine promotes mitophagy by enhancing YAP nuclear localization and Parkin expression.
- Blocking mitophagy or YAP/Parkin signaling negates the protective effects of tetramethylpyrazine.

## Abstract

Background: Mitophagy is a critical mitochondrial quality control mechanism that limits neuronal injury following cerebral ischemia/reperfusion injury (CI/RI). Tetramethylpyrazine (TMP), a bioactive alkaloid from Ligusticum chuanxiong Hort., exhibits neuroprotective effects in cerebrovascular disorders. However, whether these effects involve mitophagy regulation remains unclear. Methods: CI/RI was induced using a middle cerebral artery occlusion/reperfusion (MCAO/R) model in mice and an oxygen–glucose deprivation/reoxygenation (OGD/R) model in HT22 cells. Neurological function, infarct volume, mitochondrial function, and mitophagy-related markers were assessed. Pharmacological inhibitors and genetic manipulation of YAP and Parkin were used to investigate underlying mechanisms. Results: TMP treatment significantly reduced infarct volume and improved neurological deficits in MCAO/R mice, accompanied by enhanced mitophagy, as indicated by increased mitochondrial LC3 recruitment and Parkin expression. In OGD/R-injured HT22 cells, TMP promoted mitophagosome and mitolysosome formation, reduced mitochondrial reactive oxygen species, and restored mitochondrial membrane potential. Inhibition of mitophagy with Mdivi-1 attenuated TMP-mediated neuroprotection. Mechanistically, TMP promoted YAP nuclear localization, and inhibition of YAP or silencing of Parkin abolished TMP-induced mitophagy, while Parkin overexpression restored mitophagy under YAP inhibition. Conclusions: TMP alleviates CI/RI by promoting mitophagy through the YAP/Parkin signaling pathway, suggesting mitophagy modulation as a potential therapeutic strategy for ischemic brain injury.