3-Hydroxydehydroleucodin ameliorates neuroinflammation and ischemic brain injury by blocking the TRIM21-PRDX1 interaction.

Ischemic stroke triggers profound neuroinflammation and autophagic stress, driven predominantly by microglial overactivation. However, effective therapies targeting this pathogenesis remain elusive. Here, we report the use of 3-hydroxydehydroleucodin (3-Hyd), the primary active component from Kudiezi injection used in China for ischemic stroke patients, as a potent neuroprotective agent that markedly reduces the cerebral infarct area and improves neurological deficits in a mouse model of transient middle cerebral artery occlusion (tMCAO). Integrated bulk RNA sequencing and in vitro assays revealed that 3-Hyd significantly suppressed the microglial proinflammatory phenotype and excessive autophagic flux. Mechanistically, through chemical biology approaches, we discovered that 3-Hyd directly binds to the V51 and R128 residues of peroxiredoxin 1 (PRDX1), which physically disrupts the pathological binding of PRDX1 to its E3 ubiquitin ligase TRIM21, thus preventing the polyubiquitination of PRDX1 at the K109 residue and its subsequent proteasome degradation. Consequently, stabilized PRDX1 impedes TRAF6 ubiquitination, effectively blocking the downstream NF-κB signaling cascade. Strikingly, the anti-neuroinflammatory and cerebroprotective effects of 3-Hyd were largely abolished in microglia-specific Prdx1 conditional knockdown (Cx3cr1Cre/ERT2) mice. Together, our findings elucidate a novel TRIM21-PRDX1-TRAF6 signaling axis that governs microglial homeostasis and highlight the pharmacological stabilization of PRDX1 by 3-Hyd to block the binding of TRIM21 with PRDX1 as a promising therapeutic strategy for ischemic stroke.