Neurological abnormalities are included in the main effects of chronic lower level arsenic exposure in humans due to the consumption of contaminated drinking water. Recently, epigenetic mechanisms may explain the effects of xenobiotics. Arsenic exposure alters DNA methyltransferase (DNMT) enzyme expression and activity. It was interesting to determine if arsenic can modify other epigenetic mediators. Recently, the microRNA has been shown to regulatory effects at several molecular targets and

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... ulate physiological processes. We performed a study to determine whether hVM1 cells exposed to arsenic during differentiation have altered expression levels of miR-125b,-148a and -132, and if these changes are associated with gene expression changes in nestin, CREB, BNDF and DNMT3b using real time RT-PCR. Statistically significant changes were observed in miR-125b and miR-148a expression. Although hVM1 cells exposed to arsenic showed a trend to downregulate miR-132, this was not significant. Nestin, an important marker of diminished differentiation, was negatively correlated with miR-125b and showed a trend for increased expression that may have a physiological interpretation. In conclusion, these results show that arsenic exposure could lead changes in the expression of key microRNA and therefore could affect neural differentiation in hVM1 cells.