Resveratrol Inhibits Ionising Irradiation-Induced Inflammation in MSCs by Activating SIRT1 and Limiting NLRP-3 Inflammasome Activation

IL-1 beta, a pro-inflammatory cytokine, has been shown to contribute to radiation injury. Sirt1, an NAD(+)-dependent class III protein deacetylase, plays an important role in the regulation of the proinflammatory cytokines involved in inflammation-associated diseases. The relationship between Sirt1 and IL-1 beta, however, has remained elusive. The present study was designed to explore the potential effect of Sirt1 on IL-1 beta expression induced by radiation and to provide a new target for the development of radiation protection drugs. Our results showed that radiation significantly increased IL-1 beta mRNA and protein expression and that pretreatment with resveratrol, a Sirt1 activator, inhibited the radiation-induced IL-1 beta expression in a concentration-dependent manner, whereas the knockdown or inhibition of Sirt1 by nicotinamide significantly enhanced radiation-induced IL-1 beta expression. This effect can likely be attributed to Sirt1-mediated inhibition of NLRP-3 inflammasome activation because Sirt1 inhibits the transactivation potential of NF-kappa b by deacetylation, which then suppresses NLRP3 transcription. Taken together, the results demonstrate that Sirt1 exerts anti-inflammatory effects by regulating NLRP3 expression partially through the NF-kappa b pathway in mesenchymal stem cells. More importantly, our findings suggest that resveratrol is an effective agent in protecting against radiation injury, and we provide a theoretical basis for developing a drug to protect against radiation injury by targeting Sirt1.