Selenite protects Caenorhabditis elegans from oxidative stress via DAF-16 and TRXR-1

Abstract

Scope: Selenium is an essential micronutrient. In the present study, trace amount of selenite (0.01 μM) was evaluated for oxidative stress resistance and potential associated factors in Caenorhabditis elegans.

Methods and results: Selenite-treated C. elegans showed an increased survival under oxidative stress and thermal stress compared to untreated controls. Further studies demonstrated that the significant stress resistance of selenite on C. elegans could be attributed to its in vivo free radical-scavenging ability. We also found that the oxidative and thermal stress resistance phenotypes by selenite were absent from the forkhead transcription factor daf-16 mutant worms. Moreover, selenite influenced the subcellular distribution of DAF-16 in C. elegans. Furthermore, selenite increased mRNA levels of stress-resistance-related proteins, including superoxide dismutase-3 and heat shock protein-16.2. Additionally, selenite (0.01 μM) upregulated expressions of transgenic C. elegans carrying sod-3::green fluorescent protein (GFP) and hsp-16.2::GFP, whereas this effect was abolished by feeding daf-16 RNA interference in C. elegans. Finally, unlike the wild-type N2 worms, the oxidative stress resistance phenotypes by selenite were both absent from the C. elegans selenoprotein trxr-1 mutant worms and trxr-1 mutants feeding with daf-16 RNA interference.

Conclusion: These findings suggest that the antioxidant effects of selenite in C. elegans are mediated via DAF-16 and TRXR-1.

Keywords: Caenorhabditis elegans; DAF-16; Oxidative stress; Selenium; TRXR-1.