Beyond molecular chaperoning: AHA1 reprograms autophagy flux through direct ATP5A1 interaction in ischemic neuronal injury.

BACKGROUND: Mitochondrial dysfunction and excessive reactive oxygen species (ROS) generation play a pivotal role in ischemic neuronal injury. The Activator of 90kDa heat shock protein ATPase homolog 1 (AHSA1/AHA1) has been implicated in regulating ATP synthesis and energy metabolism. Yet, its role in neurological functional impairment and mitophagy under pathological conditions remains unclear. METHODS: We utilized in vivo middle cerebral artery occlusion/reperfusion (MCAO/R) mouse models and in vitro oxygen-glucose deprivation/reperfusion (OGD/R) neuronal cell models. The study integrated bioinformatics, molecular biology techniques, histological analyses, behavioral tests, and genetic knockdown (siRNA) to elucidate the underlying mechanisms. RESULTS: Our findings demonstrate that I/R stress induces the transcription factor STAT3 to upregulate AHA1 expression. AHA1 then translocates to the mitochondria and directly interacts with the ATP synthase subunit ATP5A1. This interaction disrupts the cellular ATP/AMP ratio and increases ROS production, leading to mitochondrial damage. The resulting energy stress triggers the aberrant activation of the AMPK/mTOR/ULK1 signaling pathway, culminating in an excessive and detrimental flux of PINK1/Parkin-mediated mitophagy. Critically, silencing of AHA1 reversed these effects, suppressing pathological mitophagy, reducing infarct volume, and improving neurological outcomes. CONCLUSION: This study reveals a novel, non-canonical function for AHA1 as a pathological driver in ischemic stroke. By directly interacting with ATP5A1, AHA1 links transcriptional stress responses to mitochondrial bioenergetic failure and excessive autophagy. Targeting the AHA1-ATP5A1 axis represents a promising therapeutic strategy to inhibit maladaptive mitophagy and protect against neurological outcomes.