Quercetin attenuates UV- and H2O2-induced decrease of collagen type I in cultured human lens epithelial cells

Ultraviolet (UV) radiation is related to cataract formation. The dynamics of matrix proteins play crucial roles in cell proliferation, cell migration, and the remodeling of lens capsule and, possibly, cataract formation. However, the change of dynamics of matrix proteins, such as collagens, in lens cells in response to UV radiation has not been investigated. Using cultured human lens epithelial cells, we, for the first time, demonstrate that UV radiation induces a decrease of collagen type I in a time- and dose-dependent manner. Hydrogen peroxide (H2O2) also induces a collagen type I decrease in a similar pattern. We observed that UV and H2O2 induce JNK and its downstream component, c-Jun, activation in both a time- and dose-dependent manner. The pharmacologic inhibitor of JNK or JNKi inhibits UV-induced JNK and c-Jun activation and attenuates a UV-induced decrease of collagen type I. Quercetin, a well known antioxidant, also protects against a UV- and H2O2-induced decrease of collagen type I in a dose-dependent manner. Quercetin inhibits UV- and H2O2-induced JNK and c-Jun activation. Collectively, we conclude that quercetin attenuates both a UV- and H2O2-induced decrease of collagen type I via the inhibiting of JNK/c-Jun activity. Understanding the cellular-signaling pathways involved in the UV- and H2O2-induced decrease of collagen type I may reveal potential therapeutic targets for the UV-induced cataract.