查看文章

MicroRNAs comprise a class of small (∼22 nucleotide) non-coding RNA species and they bind to their complementary sequence on the 3′UTR of target genes and cause translational repression. In the present study, we report that miR-29a levels are significantly elevated in the diabetic db/db mice liver. Further, we report the effects of such elevation on insulin action in HepG2 cells. Overexpression of miR-29a narrowed down insulin mediated Akt phosphorylation without altering the total Akt levels presumably due to another upstream mediator being directly targeted by miR-29a. This hunt led us to the discovery that the p85α subunit of PI3K (phosphoionositide-3-kinase), the upstream molecule in the insulin signaling cascade harbors the miR-29a binding site on its 3′UTR and a marked inhibition of PI3Kp85α was observed by this microRNA. This was consequently accompanied by attenuation of insulin inhibition …