Cr(VI), a well-known environmental chemical, is reported to cause various adverse effects on exposed organisms including
genomic instability and
carcinogenesis. Despite available information on the underlying mechanism of
Cr(VI) induced toxicity, studies regarding toxicity modulation by epigenetic mechanisms are limited. It was therefore, hypothesized that the global
miRNA profiling in
Cr(VI) exposed Drosophila, a genetically tractable model organism, will provide information about mis-regulated
miRNAs along with their targeted genes and relevant processes. Third instar larvae of Drosophila melanogaster (Oregon R(+)) were exposed to 5.0-20.0 μg/ml of
Cr(VI) for 24 and 48 h. Following
miRNA profile analysis on an Agilent platform, 28 of the 36 differentially expressed
miRNAs were found to be significantly mis-regulated targeting major biological processes viz., DNA damage repair, oxidation-reduction processes, development and differentiation. Down-regulation of mus309 and mus312 under DNA repair, acon to oxidation-reduction and pyd to stress activated MAPK cascade respectively belonging to these gene ontology classes concurrent with up-regulation of dme-miR-314-3p, dme-miR-79-3p and dme-miR-12-5p confirm their functional involvement against
Cr(VI) exposure. These findings assume significance since majority of the target genes in Drosophila have functional homologues in humans. The study further recommends Drosophila as a model to explore the role of
miRNAs in
xenobiotic induced toxicity.