Mitochondria-Associated mRNAs Restore ATP During Oxidative Stress via Cytosolic Translation

Mitochondrial transplantation has been proposed as a strategy to restore cellular bioenergetics after oxidative injury, but the mechanisms governing ATP recovery remain unclear. Using placental mitochondria, we examined ATP restoration following H₂O₂-induced oxidative stress. Unmodified mitochondria modestly increased ATP under baseline conditions but failed to restore ATP after injury. In contrast, lipid-coated mitochondria (MitoCoat) and lipid-encapsulated mitochondria-associated mRNAs (MitoCoat-mRNA) significantly increased ATP levels in injured cells. Transcriptomic analyses revealed that ATP recovery occurred without the normalization of canonical glycolytic or oxidative phosphorylation (OXPHOS) gene programs. Instead, unmodified mitochondria induced broad transcriptional responses associated with immune activation and cellular stress, whereas MitoCoat elicited a more restricted transcriptional profile. Notably, mitochondria-associated mRNAs alone restored ATP without detectable changes in host transcriptional programs. The removal of mitochondrial surface-associated ribosomes or the inhibition of cytosolic but not mitochondrial translation attenuated ATP recovery. The restoration of key metabolic enzymes through cytosolic translation, including PFKP, pyruvate dehydrogenase, and ATP synthase subunit ATP5A suggests that mitochondria-associated mRNAs promote recovery by re-establishing coupling between glycolysis and mitochondrial OXPHOS. Together, these findings identify encapsulated mitochondria-associated mRNAs as a potential strategy to restore cellular bioenergetics under oxidative stress.