Effect of cadmium on kitl pre-mRNA alternative splicing in murine ovarian granulosa cells and its associated regulation by miRNAs.

In this study, we established an in vitro exposure model of murine ovarian granulosa cells to observe the effect of Cd on alternative splicing of the kitl pre-mRNA and subsequently to explore the role of kitl gene expression regulation-related miRNAs through miRNA prediction, miRNA chip, bioinformatics and real-time quantitative polymerase chain reaction analyses. Our results showed that the kitl1/kitl2 mRNA ratio was significantly different (P < 0.05) at different dosages and times. The miRNA chip analysis showed that the miRNA expression profiles for the Cd treatment were significantly changed, and the expression of 29 miRNAs involved in alternative splicing of the kitl pre-mRNA was changed. The gene ontology analysis showed that the target gene functions of these 29 miRNAs were mainly enriched in the biological processes of cell metabolism regulation, post-transcriptional regulation of mRNA, interleukin-6-mediated signal transduction, cell cycle, cell proliferation, differentiation and migration. The pathway enrichment analysis showed that the target genes of the differentially expressed miRNAs were mainly enriched in the Ras signaling pathway, the Rap1 signaling pathway, the Foxo signaling pathway, the Hippo signaling pathway, the MAPK signaling pathway and the carcinogenic pathway. Polymerase chain reaction verification results showed that compared to the control group, the variation trends in the expression of mmu-miR-27a-3p, mmu-miR-34b-5p, mmu-miR-297a-3p, mmu-miR-129-5p and mmu-miR-107-3p in the 4 hour 10 μm Cd treatment group were basically the same as that of the chip result. Our results indicate that Cd exposure can affect alternative splicing of the kitl pre-mRNA in ovarian granulosa cells, and miRNAs play regulatory roles in the alternative splicing of kitl.