Discovery of a novel mitophagy inducer attenuating postoperative cognitive dysfunction through structure-based...

Postoperative cognitive dysfunction (POCD), a prevalent complication following surgery and anesthesia, currently lacks effective therapeutics. Given the crucial regulatory role of the PTEN-induced kinase 1 (PINK1)/Parkin-mediated mitophagy in maintaining mitochondrial homeostasis and suppressing neuroinflammatory responses, we aimed to identify novel mitophagy inducers as potential therapeutic interventions for POCD. Employing structure-based virtual screening of a small-molecule library of compounds, we identified tamarixetin as a potent and selective PINK1 activator. Comprehensive molecular dynamics simulations and cellular thermal shift assays validated its stable binding interaction with PINK1. Treatment with tamarixetin significantly enhanced mitophagic activity in the hippocampal region of surgically treated mice, concurrently reducing cytosolic mitochondrial DNA accumulation and reactive oxygen species levels, attenuating neuroinflammatory responses, and improving cognitive function in behavioral tests. Mechanistically, tamarixetin treatment promoted PINK1 stabilization and strengthened PINK1-Translocase Of Outer Mitochondrial Membrane 40 interactions, while facilitating Parkin recruitment to mitochondria and enhancing mitofusin 2 ubiquitination, ultimately promoting mitophagic flux in both lipopolysaccharide-stimulated HT22 neuronal and BV2 microglial cell lines. Our study identifies tamarixetin as a novel pharmacological activator of PINK1-dependent mitophagy and elucidates its therapeutic potential in POCD by counteracting mitochondrial dysfunction and neuroinflammation. These findings provide a promising foundation for developing mitophagy-targeted therapies for POCD.