Hepatic miR-181b-5p Contributes to Glycogen Synthesis Through Targeting EGR1

• Published in: Digestive diseases and sciences 2019-06, Vol.64 (6), p.1548-1559
• Main Authors: Wang, Shuyue, Liang, Chen, Ai, Huihan, Yang, Meiting, Yi, Jingwen, Liu, Lei, Song, Zhenbo, Bao, Yongli, Li, Yuxin, Sun, Luguo, Zhao, Huiying
• Format: Article
• Language: English
• Subjects: Adult; Analysis; Animals; Biochemistry; Dextrose; Diabetes; Diabetes Mellitus, Type 2 - genetics; Diabetes Mellitus, Type 2 - metabolism; Disease Models, Animal; Early Growth Response Protein 1 - genetics; Early Growth Response Protein 1 - metabolism; Female; Gastroenterology; Glucose; Glycogen; Glycogen - biosynthesis; Hep G2 Cells; Hepatology; Humans; Insulin Resistance; Kinases; Liver - metabolism; Male; Medicine; Medicine & Public Health; Mice, Inbred C57BL; MicroRNAs - genetics; MicroRNAs - metabolism; Middle Aged; Oncology; Original Article; PTEN Phosphohydrolase - metabolism; Signal Transduction; Synthesis; Transplant Surgery; Type 2 diabetes
• ISSN: 0163-2116; 1573-2568
• DOI: 10.1007/s10620-018-5442-4

Background/Aim The miR-181 family plays an important role in the regulation of various cellular functions. However, whether miR-181b-5p mediates hepatic insulin resistance remains unknown. In this study, we investigated the effect of miR-181b-5p on the regulation of hepatic glycogen synthesis. Methods The miR-181b-5p levels in the livers of diabetic mice were detected by real-time PCR. The glycogen levels and AKT/GSK pathway activation were examined in human hepatic L02 cells and HepG2 cells transfected with miR-181b-5p mimic or inhibitor. The potential target genes of miR-181b-5p were evaluated using a luciferase reporter assay and Western blot analysis. EGR1-specific siRNA and pCMV-EGR1 were used to further determine the role of miR-181b-5p in hepatic glycogen synthesis in vitro. Hepatic inhibition of miR-181b-5p in mice was performed using adeno-associated virus 8 (AAV8) vectors by tail intravenous injection. Results The miR-181b-5p levels were significantly decreased in the serum and livers of diabetic mice as well as the serum of type 2 diabetes patients. Importantly, inhibition of miR-181b-5p expression impaired the AKT/GSK pathway and reduced glycogenesis in hepatocytes. Moreover, upregulation of miR-181b-5p reversed high-glucose-induced suppression of glycogenesis. Further analysis revealed that early growth response 1 (EGR1) was a downstream target of miR-181b-5p. Silencing of EGR1 expression rescued miR-181b-5p inhibition-reduced AKT/GSK pathway activation and glycogenesis in hepatocytes. Hepatic inhibition of miR-181b-5p led to insulin resistance in C57BL/6 J mice. Conclusion We demonstrated that miR-181b-5p contributes to glycogen synthesis by targeting EGR1, thereby regulating PTEN expression to mediate hepatic insulin resistance.