HIF-1α/STOML2 mediated PINK1-dependent mitophagy activation against hypoxia-induced neuronal injury

Abstract

Hypoxia contributes to brain disorders by causing neuronal injury. However, in the early stage of stress, neurons initiate a series of compensatory pathways to resist cell damage, but the underlying mechanisms have not been fully elucidated. In this study, we found that hypoxia transiently activates PTEN-induced kinase 1 (PINK1)-dependent mitophagy in the early stage before cell damage and neurological dysfunction. PINK1 overexpression protects neurons and it knockdown exacerbates neuronal damage, highlighting the key role of PINK1-dependent mitophagy in hypoxic adaptation. Mechanistically, hypoxia promotes HIF-1 nuclear translocation, inducing transcription of stomatin like 2 (STOML2). STOML2 relocates to the mitochondrial membrane, aiding phosphoglycerate mutase 5 (PGAM5) cleavage, which triggers PINK1-dependent mitophagy. Silencing HIF-1, STOML2, or PGAM5 inhibits PINK1-dependent mitophagy and worsens neurological function under hypoxia. Notably, intermittent hypoxia, a hypoxic conditioning strategy for improving hypoxic tolerance, enhances PINK1-dependent mitophagy by activating HIF-1/STOML2 axis, and protects neurons against hypoxia. In conclusion, our study reveals a new "self-protection" mechanism of neurons against hypoxic stress and discovers that intermittent hypoxia is a potential therapeutic strategy against hypoxia-induced injury.