Ultraviolet A(320-400 nm)modulation of ultraviolet B(290-320 nm)-induced immune suppression is mediated by carbon monoxide

摘要

Accumulating evidence suggests that suberythemogenic UVA exposure protects against the immunosuppressive effect of UVB radiation or its epidermal photoproduct,ris-urocanic acid(cis-UCA).In skin,UVA photoimmunoprotection is mediated by the inducible antioxidant stress enzyme heme oxygenase-1(HO-1),which degrades heme into carbon monoxide(CO),iron,and biliverdin(reduced to bilirubin),and is important for cell survival under conditions of oxidative stress.The identity of the HO enzymatic product(s)that provide the immunoprotec-tion is unknown.