Supplementary data for: IRG1/itaconate inhibits microglial senescence-like transition by modulating mitochondrial dynamics through RhoA alkylation in subarachnoid hemorrhage

This study investigates the immunometabolic regulation of the microglial senescence-like transition following SAH, focusing on the immune-responsive gene 1 (IRG1)/itaconate axis. We observed that the endogenous upregulation of IRG1 and itaconate is a protective response to hemorrhagic stress that is significantly blunted in aged mice.

Microglia-specific IRG1 deficiency exacerbated SAH-induced brain injury, characterized by an accelerated senescence-like transition and the secretion of senescence-associated secretory phenotype (SASP) factors. Mechanistically, we demonstrate that IRG1 deficiency leads to excessive mitochondrial fission and dysfunction via the hyperactivity of Dynamin-related protein 1 (Drp1). Using click chemistry-based proteomics and site-directed mutagenesis, we identified that itaconate exerts its neuroprotective effects by directly alkylating the small GTPase RhoA at the cysteine 107 (C107) residue.