TRIM27 promotes microglial M2 polarization and neuroprotection via TBK1-dependent autophagy in cerebral ischemia-reperfusion injury.

Microglial activation and dysfunction play pivotal roles in the pathogenesis of ischemic stroke, yet the molecular mechanisms governing their phenotypic plasticity and protective functions remain incompletely understood. Here, we integrated transcriptomic profiling with functional validation to identify TRIM27 as a novel regulator of microglial autophagy and polarization following cerebral ischemia-reperfusion injury. RNA sequencing of CD11b+ microglia isolated from mice subjected to middle cerebral artery occlusion (MCAO) revealed significant downregulation of Trim27, which was associated with impaired autophagy pathways. In vivo overexpression of TRIM27 via AAV9 delivery markedly attenuated infarct volume, neuronal degeneration, and apoptosis after MCAO. This neuroprotection was accompanied by a shift in microglial phenotype from pro-inflammatory M1 toward anti-inflammatory M2 states, along with enhanced autophagic flux. In vitro, TRIM27 overexpression in oxygen-glucose deprivation/reoxygenation (OGD/R)-treated microglia suppressed mitochondrial reactive oxygen species production and lipid peroxidation, improving cell survival. Mechanistically, TRIM27 physically interacted with and stabilized TANK-binding kinase 1 (TBK1) by inhibiting its ubiquitin-mediated degradation. Notably, genetic ablation of Tbk1 abolished the beneficial effects of TRIM27 on microglial polarization, autophagy, oxidative stress, and neuroprotection both in vivo and in vitro. Our findings establish a TRIM27-TBK1 axis as a critical modulator of microglial function in ischemic stroke, highlighting its potential as a therapeutic target for promoting brain repair through autophagy-dependent immunomodulation.