MiR‐103 modulates G1/S transition in IGF‐1 stimulated mouse intestinal crypt cell proliferation

Abstract

microRNAs play extensive roles in cellular development. Analysis of the microRNA expression pattern during intestinal cell proliferation in early life is likely to unravel molecular mechanisms behind intestinal development and have implications for therapeutic intervention. In this study, we examined differences in microRNA expression and identified miR‐103 as a regulator in IGF‐1 stimulated proliferation of mouse intestinal crypt cells. Mouse intestinal crypt cells were cultured and treated with IGF‐1 for 24 h, microRNA microarrays showed that multiple microRNAs are regulated by IGF‐1, and miR‐103 was the most sharply down‐regulated among these microRNAs. Expression of miR‐103 in mouse intestinal crypt cells was confirmed by real‐time Q‐PCR. Sequence analyses showed that, among the 1040 predicted miR‐103 target genes, CCNE1, CREB1, IGFBP1, and CDKL2 contain complementary sequences to the miR‐103 seed region and are conserved between human and mouse. We further demonstrated that miR‐103 directly controls the expression level of the four genes by luciferase assay and immunoblotting assay, respectively. Taken together, our data suggest that in mouse crypt cells, miR‐103 is part of the G1/S transition regulation network, which targets CCNE1, CREB1, and CDKL2 during IGF‐1 stimulated proliferation. (Supported by Mead Johnson Nutrition)