Hydrogen Peroxide Induces Adaptive Response and Differential Gene Expression in Human Embryo Lung Fibroblast Cells

摘要

Hydrogen peroxide (H_2O_2), a substance involved in cellular oxidative stress, has been observed to induce an adaptive response, which is characterized by a protection against the toxic effect of H_2O_2 at higher concentrations. However, the molecular mechanism for the adaptive response remains unclear. In particular, the existing reports on H_2O_2-induced adaptive response are limited to animal cells and human tumor cells, and relatively normal human cells have never been observed for an adaptive response to H_2O_2. In this study, a human embryo lung fibroblast (MRC-5) cell line was used to model an adaptive response to H_2O_2, and the relevant differential gene expressions by using fluoro mRNA differential display RT-PCR. The results showed significant suppression of cytotoxicity of H_2O_2 (1100 μM, 1 h) after pretreatment of the cells with H_2O_2 at lower concentrations (0.088-8.8 μM, 24 h), as indicated by cell survival, lactate dehydrogenase release, and the rate of apoptotic cells. Totally 60 mRNA components were differentially expressed compared to untreated cells, and five of them (sizing 400-600 bp) which demonstrated the greatest increase in expression were cloned and sequenced. They showed identity with known genes, such as BCL-2, elF3S5, NDUFS4, and RPS10. Real time RT-PCR analysis of the five genes displayed a pattern of differential expression consistent with that by the last method. These five genes may be involved in the induction of adaptive response by H_2O_2 in human cells, at least in this particular cell type.