Regulation of heat shock protein synthesis in human skin fibroblasts in response to oxidative stress: role of vitamin E

Skin plays an important role in protection against oxidative stressors such as ultraviolet radiation, ozone and chemicals. Chronic sun exposure causes degenerative changes in the skin that are recognized as photoaging. Oxidative stress has been shown to alter the expression of mammalian antioxidant enzymes as well as to enhance numerous transcription factors, including nuclear factor κB, stress-activated protein kinase and heat shock factor. This latter is the transcription factor for the synthesis of heat shock proteins, which have been known to protect against a wide variety of toxic conditions, including extreme temperatures, oxidative stress and cytotoxic drugs. In this study we investigated the role of oxidative stress in the induction of heat shock protein (HSP) 70 in human skin fibroblasts and the effect of vitamin E. We found that significant HSP70 induction occurred after exposure to HOOH and that this was associated with a significant pertubation in protein and nonprotein sulfhydryl groups, and with a significant increase in protein carbonyl levels. Treatment with vitamin E conferred significant protection against stress-induced modifications of cellular sulfhydryl and carbonyl content, while maintaining functional levels of cytoprotective HSP70. Our results point to the possible involvement of redox mechanisms in the heat shock signal transduction pathway, which may play an important regulatory role in the genetic mechanisms of tolerance to oxidative stress. Exogenous antioxidant supplementation with vitamin E could have cosmetic benefits and may be an efficient tool to mitigate the consequences of free radical-induced skin damage.