Peroxiredoxin I plays a protective role against UVA irradiation through reduction of oxidative stress.

BACKGROUND: Exposure of skin to long-wave UV radiation (UVA) increases the cellular levels of reactive oxygen species (ROS), which have been linked to apoptosis induction through the damage of lipids, proteins, and nucleic acids. Peroxiredoxin I (Prx I) is one of a family of antioxidant proteins that plays a protective role against oxidative damage; however the role of Prx I in UVA-induced damage remains to be clarified.

OBJECTIVE: Here we investigated the protective role of Prx I against UVA-induced changes using mouse embryonic fibroblasts (MEFs) derived from Prx I homozygous knockout (Prx I (-/-)) mice.

METHODS: Prx I (-/-) and wild-type (Prx I (+/+)) MEFs were subjected to UVA irradiation, and the resulting apoptosis was analyzed using flow cytometry, quantitative real-time PCR, and western blotting.

RESULTS: Prx I (-/-) MEFs showed enhanced sensitivity to UVA treatment, exhibiting increased apoptosis and ROS production compared to Prx I (+/+) MEFs. Consistent with the increase in apoptosis, p53 expression was significantly higher, while Bcl-2, Bcl-xL, and Nrf2 expressions were all lower in Prx I (-/-) versus (+/+) MEFs. The UVA-induced inflammatory response was upregulated in Prx I (-/-) MEFs, as indicated by increased expressions of IκB, TNFα, and IL-6. Evidence was presented indicating that Prx I impacts these pathways by modifying critical signaling intermediates including p53, IκB, and Nrf2.

CONCLUSION: Our results indicate that Prx I plays a protective role against UVA-induced oxidative damage by controlling ROS accumulation. Both the UVA-induced apoptotic and inflammatory signals were found to be modulated by Prx I.