Palmitic Acid Regulates miRNA-3148 via Insulin Receptor Substrate-1 and is Involved in Insulin Resistance

Abstract

Previous studies reported that saturated fatty acid palmitic acid (PA) is closely related to insulin resistance. miR-3148 regulates insulin receptor substrate-1 (IRS1) predicted by MiRDB analysis. However, whether PA regulates IRS1 via miR-3148 remains to be elucidated. Therefore, in this work, we assessed whether PA regulates miRNA-3148 via IRS1 in insulin resistance. We cultured HepG2 cells in vitro and classified them into control group (NC group), miR-3148 Mimics group, and miR-3148 Mimics+ pFBD-IRS1 group. We used qRT-PCR to detect miR-3148 and IRS1 mRNA; used Dual-Luciferase Reporter Assays to detect miR-3148 with 3′-UTR region of IRS1 mRNA; and utilized Western blot (WB) to detect IRS1, p-AKT, AKT and Tubulin. Our results showed that PA could increase miR-3148 and decrease IRS1 which is a target protein of miR-3148, as shown by Dual-Luciferase Reporter assays. miR-3148 significantly inhibited the impact of insulin on p-AKT level (P < 0.01) and over-expression of IRS1 by pFBD-IRS1 can partially alleviate the inhibitory effect of miR-3148 mimics on p-AKT. In HepG2 cells, PA regulates miR-3148. Via targeting IRS1 mRNA, miR-3148 impairs insulin signaling pathway, leading to insulin resistance. Over-expression of IRS1 by pFBD-IRS1 alleviates miR-3148-induced insulin resistance.