Expression of β-catenin in oxidative stress-induced premature senescence of human skin fibroblasts

Abstract

Objective To observe the changes of β-catenin expression in human skin fibroblasts (HSFs) after induced by oxidative stress, and to explore its possible roles in oxidative stress-induced premature senescence (SIPS) of HSFs. Methods Fibroblasts were isolated from the foreskin of a child and subjected to a primary culture. The fibroblasts of second to fourth passage were treated with various concentrations of H2O2 for 2 hours to establish an optimized model of stress-induced premature senescence, β-galactosidase assay kit was used to detect the activity of β-galactosidase in H2O2rinduced HSFs, RT-PCR and Western blot to measure the mRNA and protein expressions of β-catenin in control and senescent HSFs. Results Premature senescence of HSFs could be induced by the treatment with H2O2 of 150 μmol/L for 2 hours. The proportion of β-galactosidase-positive cells was (2.97 ± 0.25)% in control HSFs and (37.67 ± 1.53)% in senescent HSFs (P< 0.01). A significant increase was observed in the β-catenin/GAPDH protein ratio and β-catenin/GAPDH mRNA ratio in control HSFs compared with the senescent HSFs (0.62 ± 0.03 vs. 0.31 ± 0.01, t = 14.97, P < 0.01; 0.59 ± 0.04 vs. 0.29 ± 0.30, t = 10.06, P < 0.01). Conclusions The two-hour treatment with H2O2 of 150 μmol/L could induce the premature senescence of HSFs, and there is a notable decrease in the expression of β-catenin in prematurely senescent HSFs induced by oxidative stress, implying that β-catenin is an important target gene for the regulation of skin aging. Key words: Fibroblasts; beta Catenin; Cell aging; beta-Galactosidase