PHB2 perturbation is associated with NDUFS2-linked mitochondrial phenotypes, GPX4 abundance, and ferroptosis-related responses in experimental parkinsonian models

Ferroptosis-related lipid damage and mitochondrial complex I dysfunction have both been implicated in dopaminergic neurodegeneration, but their relationship remains incompletely defined. We examined whether modulation of prohibitin 2 (PHB2), an inner mitochondrial membrane scaffold, was associated with lipid-peroxidation/redox responses and explored its relationships with NDUFS2-linked mitochondrial phenotypes and GPX4 abundance in cellular and acute toxin models of parkinsonism. In MPP⁺-treated undifferentiated SH-SY5Y cells, PHB2 overexpression was associated with lower lipid-peroxidation-related readouts, higher GSH and GPX4 abundance, preserved mitochondrial membrane potential and complex I activity, and a higher CCK-8 metabolic signal; PHB2 knockdown showed generally opposite associations. In male mice given striatal AAV9-PHB2 before acute MPTP exposure, PHB2 overexpression was associated with smaller locomotor and tissue-redox abnormalities and a smaller reduction in the TH-positive neuronal-profile measure. PHB2 and NDUFS2 were biochemically co-recovered. One NDUFS2 shRNA attenuated several PHB2-overexpression-associated phenotypes, whereas NDUFS2-Flag co-expression in PHB2-knockdown cells produced partial reciprocal shifts. Additional four-condition immunoblots documented PHB2 and NDUFS2 abundance in molecular-control samples, but complete functional controls remained absent. These designs did not distinguish a specific PHB2–NDUFS2 relationship from an independent mitochondrial effect of NDUFS2 perturbation. GPX4 abundance changed during CHX exposure and proteasome inhibition, and PHB2 and OTUB1 were detected in GPX4 immunoprecipitates. The original Fig. 6 ubiquitination assays were not normalized to recovered GPX4. In a separate OTUB1 WT/C91S/D88A experiment, GPX4-associated ubiquitin signals were normalized to same-IP recovered GPX4 and differed among re-expression conditions, but this did not establish direct enzymatic deubiquitination. PHB2 abundance was associated with NDUFS2-linked mitochondrial phenotypes, proteasome-sensitive changes in GPX4 abundance, and ferroptosis-related cellular responses during experimental parkinsonian stress. The findings define testable associations and do not establish a linear PHB2–NDUFS2/OTUB1–GPX4 pathway, a direct OTUB1-dependent deubiquitination mechanism, ferroptotic cell death, neuronal survival, a cell-autonomous dopaminergic-neuron mechanism, or efficacy after disease onset.