The NAD+/NADH ratio was reduced and sirtuin activity was impaired. We identified alpha tubulin as the major acetylated protein from DRG homogenates whose levels were increased in FXNI151F mice compared to WT mice. In the mitochondria, superoxide dismutase (SOD2), a SirT3 substrate, displayed increased acetylation in frataxin-deficient DRG neurons. Since SOD2 acetylation inactivates the enzyme, and higher levels of mitochondrial superoxide anion were detected, oxidative stress markers were analyzed. Elevated levels of hydroxynonenal bound to proteins and mitochondrial Fe2+ accumulation was detected when frataxin decreased. Honokiol, a SirT3 activator, restores mitochondrial respiration, decreases SOD2 acetylation and reduces mitochondrial superoxide levels. Altogether, these results provide data at the molecular level of the consequences of electron transport chain dysfunction, which starts negative feedback, contributing to neuron lethality. This is especially important in sensory neurons which have greater susceptibility to frataxin deficiency compared to other tissues.
Tuesday, December 26, 2023
Mitochondrial impairment, decreased sirtuin activity and protein acetylation in dorsal root ganglia in Friedreich Ataxia models
Arabela Sanz-Alcázar, Elena Britti, Fabien Delaspre, Marta Medina-Carbonero, Maria Pazos-Gil, Jordi Tamarit, Joaquim Ros & Elisa Cabiscol. Mitochondrial impairment, decreased sirtuin activity and protein acetylation in dorsal root ganglia in Friedreich Ataxia models. Cell. Mol. Life Sci. 81, 12 (2024). doi:10.1007/s00018-023-05064-4
