379 Targeting SIRT2 Sensitizes Microglia to Ferroptosis by Promoting Mitophagy and Inhibiting GPX4 in Subarachnoid Hemorrhage

INTRODUCTION: A large amount of iron ions are released after aneurysmal subarachnoid hemorrhage, causing neuroinflammatory damage and triggering ferroptosis. At the same time, mitochondria are crucial for iron metabolism and ferroptosis. SIRT2 is an NAD+-dependent deacetylase that regulates mitochondrial autophagy. METHODS: ELISA, qPCR and western blot detected the expression level of SIRT2, western blot and immunofluorescence detected the expression levels of ferroptosis-related genes and proteins, transmission electron microscopy observed mitochondrial damage, and also detected changes in ferroptosis-related indicators such as MDA and ROS. RESULTS: We found that the expression of SIRT2 in the cerebrospinal fluid of SAH patients was higher than those of healthy patients in clinical work, and it was related to the patient's prognosis. Further bioinformatics analysis found that the ferroptosis-related GPX4 protein is closely related to SIRT2. When ferroptosis is induced in cells, SIRT2 expression is upregulated, and inhibition of SIRT2 leads to the accumulation of ferrous iron and ROS in mitochondria, triggering mitophagy. In addition, the mitophagy pathway was upregulated while GPX4 was downregulated after SIRT2 was knockdown. Forced expression of GPX4 in SAH with SIRT2 knockdown restored cellular cystine uptake and consequently the cellular GSH level, thereby partially rescuing cell viability upon RSL3 treatment. Furthermore, SIRT2 regulates GPX4 transcription through NRF2 in SAH. CONCLUSIONS: In conclusion, our results elucidated a novel mechanism of the ability of targeting SIRT2 to protect against ferroptosis after SAH and provided insights into a potential combination approach to target SIRT2 and induce SAH to treat ferroptosis.