RESUMO
OBJECTIVE To analyze trimethylation of genome-wide histone H3 lysine 4(H3K4met3) induced by silicon dioxide(SiO2)through chromatin immunoprecipitation linked to microarrays(ChIP-chip)in lung fibroblast(LF)of rats. METHODS A primary co-culture model of rat alveolar macrophages (AM)and LF in vitro. AM were exposed to 100 mg · L-1 free SiO2 for 24 h,before LF were collected and the phenotype of LF was determined after transdifferentiation by immunohistochemistry. ChIP-chip was used to profile the variations of trimethylation in H3K4 of lung fibroblasts in CpG island regions. ChIP-qPCR was used to validate the microarray results. The mRNA expression of nfib and kpna3 was analyzed by qRT-PCR. RESULTS Totally 1815 (518 increased and 1297 decreased) genes of H3K4met3 displayed significant differences in SiO2 100 mg·L-1 group compared with control group(Cy3/Cy5 value>2.0 or <0.5,NimbleScan V2.5 software). The results of ChIP-qPCR were quite consistent with those of microarray. CONCLUSION There are significant differences in methylation of genome-wide H3K4 between SiO2 100 mg·L-1 group and control group. These novel candidate genes may become potential biomarkers or new interfered targets.