Paper 132

Abstract Title:

EFFECTS OF BETACAROTENE ON UVA-INDUCED MMP1 EXPRESSION IN HACAT CELLS

Authors:

R. Goralczyk, N. Seifert, K. Wertz, P. Buchwald and G. Riss

Institutions:

F. Hoffmann-La Roche, Vitamins, CH-4070 Basel, Switzerland

Key Words:

Abstract:

Solar-light has a strong oxidative component in the UVA/near visible spectrum of 320 to 400nm. Antioxidant compounds, including carotenoids as powerful singlet oxygen quenchers, have been suggested to protect against oxidative stress caused by UV light. To address this hypothesis, we studied the effects of betacarotene in HaCat skin keratinocytes on UVA- and singlet oxygen inducible genes such as collagenase 1 (metalloprotease 1, MMP1).
HaCat cells were cultured with up to 3.05mol/L betacarotene alone or in the presence of 505Mol/L vitamin E in the culture medium. Uptake of betacarotene into the cells was assayed by HPLC. Cells were exposed to UVA with a Hvnle solar lamp by filtering UVB with a glass plate. MMP1 response to UVA was measured on the RNA level by TaqMan. Realtime quantitative RT-PCR as well as on the protein level by ELISA.
Uptake of betacarotene by HaCat cells was time- and dose-dependent. Betacarotene concentrations in cells were significantly reduced after UVA irradiation. Supplementation of cells with betacarotene before and after UVA exposure, alone or in combination with vitamin E, prevented UVA-induced MMP1 upregulation (approx. 50% reduction compared to vehicle treated cells). Vitamin E alone also reduced MMP1, however, a clear synergistic effect betacarotene was not observed. In summary, this shows that antioxidants can downregulate collagenase in skin cells which implicates a possible role in photoaging.