Allicin alleviates cerebral ischemia/reperfusion injury by inhibiting neuronal mitochondrial oxidative stress via OTUD1/NRF2 axis.

BACKGROUND

Allicin, (diallyl thiosulfinate), the major contributor to the odor of freshly crushed garlic (Allium sativum L.), exhibits antioxidant and anti-inflammatory effects. The exact role of allicin in alleviating cerebral ischemia/reperfusion injury (CIRI) remains unclear.

PURPOSE: To elucidate the role and underlying mechanisms of allicin in alleviating CIRI.

METHODS

Male C57BL/6J mice were subjected to middle cerebral artery occlusion followed by reperfusion to trigger CIRI. Neurological function and histological analysis of allicin-treated mice were evaluated after CIRI induction. Allicin-upregulated OTU deubiquitinase 1 (OTUD1) was detected in mice with CIRI using RNA-sequencing. Data-independent acquisition based on quantitative proteomics was used to characterize the differential protein expression profiles in the ischemic cerebral tissues of mice following CIRI. OTUD1 was further upregulated to explore its role in oxidative stress in the mitochondria in allicin-treated mice and oxygen-glucose deprivation/reoxygenation-induced neuronal cells. The regulatory mechanism of OTUD1 on nuclear factor erythroid 2-related factor 2 (NRF2) was evaluated using immunoprecipitation, denatured immunoprecipitation, and nuclear-cytoplasmic fractionation assays. The OTUD1/NRF2 axis in allicin-treated neuronal mitochondrial oxidative stress was determined in vivo and in vitro.

RESULTS

Allicin treatment improved neurological function, reduced cerebral infarct volume, and attenuated brain edema in mice with CIRI. RNA-sequencing revealed OTUD1 as the downstream gene in allicin-treated mice after CIRI. Differential protein expression profiles revealed that the protective role of allicin correlated with neuronal mitochondrial oxidative stress. In vitro findings demonstrated that allicin suppressed CIRI-induced mitochondrial oxidative stress by enhancing OTUD1 expression. Mechanistic studies revealed that allicin inhibited NRF2 degradation via OTUD1-mediated deubiquitination and that OTUD1 promoted the nuclear translocation of NRF2. Allicin could also inhibit neuronal mitochondrial oxidative stress via the OTUD1/NRF2 axis both in vivo and in vitro.

CONCLUSION

Our findings demonstrate the neuroprotective role of allicin in CIRI. Furthermore, it is the first study to provide evidence that allicin exerts its neuroprotective effects primarily through activation of the OTUD1/NRF2 axis.