Genome-wide pathways analysis of nickel ion-induced differential genes expression in fibroblasts

To reveal molecular mechanisms of the interaction between Ni2+ and cells, cDNA microarray technology and GenMAPP analysis were utilized to investigate changes of gene expression profile and identify significant biological pathways in mouse fibroblast cells (L-929) treated by 100 microm Ni2+ for 12, 24, 48 and 72 h, respectively. The microarray data was validated by real-time PCR. Methylthiazoltetrazolium (MTT) analysis and flow cytometry experiment were used to assess the cellular response of L-929 cells to Ni2+. It was found that six main biological pathways were affected by Ni2+ with 118 differentially expressed genes involved. Further analysis illuminated that the exposure of cells to Ni2+ may evoke series of cellular responses to hypoxia by regulating hypoxia-inducible gene expression and cause irreversible DNA damage. Cell cycle pathway analysis results showed DNA replication in S phase could be inhibited by Ni2+ which was consistent with the data gained from flow cytometry experiment. Compared to previous researches based on conventional molecular biology experiments, the present work has not only indirectly validated the findings of other groups but also obtained several discoveries related to cell-Ni2+ interaction, such as inhibition of electron transport chain and accumulation of extracellular matrix (ECM) collagens. The routine of the present study not only can analyze gene expression profile but also may provide a more convenient and efficient approach to explain molecular mechanisms of cell-biomaterial interaction.