Hepatic miR-378 targets p110α and controls glucose and lipid homeostasis by modulating hepatic insulin signalling

Wei Liu, Hongchao Cao, Cheng Ye, Cunjie Chang, Minghua Lu, Yanyan Jing, Duo Zhang, Xuan Yao, Zhengjun Duan, Hongfeng Xia, Yu-cheng Wang, Jingjing Jiang (+3 others)
2014 Nature Communications  
Understanding the regulation of insulin signalling in tissues provides insights into carbohydrate and lipid metabolism in physiology and disease. Here we show that hepatic miR-378/378* expression changes in response to fasting and refeeding in mice. Mice overexpressing hepatic miR-378/378* exhibit pure hepatic insulin resistance. miR-378 inhibits hepatic insulin signalling through targeting p110a, a subunit of PI3K and hence a critical component of insulin signalling. Knockdown of hepatic p110a
more » ... wn of hepatic p110a mimics the effect of miR-378, while restoration of p110a expression abolishes the action of miR-378 on insulin signalling as well as its systemic effects on glucose and lipid homeostasis. miR-378/378* knockout mice display hypoglycemia and increased hepatic triglyceride level with enhanced insulin sensitivity. Inhibition of hepatic p110a in miR-378/378* knockout mice corrects the abnormal glucose tolerance. Finally, we show that overexpression of hepatic miR-378/378* ameliorates hepatic steatosis in ob/ob mice without exacerbating hyperglycemia. Our findings establish fasting-responsive miR-378 as a critical regulator of hepatic insulin signalling. Figure 1 | miR-378/378* overexpression dysregulates glucose/lipid homeostasis. (a) The levels of miR-378/378* in the liver of fed, fasted and refed mice (n ¼ 5). Means±s.e.m. are shown. **Po0.01 versus fed mice; # Po0.05 versus fasted mice; ## Po0.01 versus fasted mice. (b) Time course of random glucose levels of mice after Ad-null or Ad-378 infection (n ¼ 9-10). Blood glucose levels (c, n ¼ 15-17) and insulin levels (d, n ¼ 8-9) of mice infected with Ad-null or Ad-378 were examined under different feeding conditions. (e-g) Glucose-tolerance test (GTT; e, n ¼ 6-7), insulin-tolerance test (ITT; f, n ¼ 9-10) and pyruvate-tolerance test (PTT) (g, n ¼ 9-10) were performed in mice infected with Ad-null or Ad-378. Area under the curve (AUC) data for GTT (e), ITT (f) and PTT (g) tests were calculated, respectively. The expression of G6Pase, PEPCK, PGC-1a and SHP in the liver of mice (h, n ¼ 5) or mouse primary hepatocytes (i, n ¼ 3) infected with Ad-null or Ad-378 as indicated. PAS staining (j) and glycogen assay (k, n ¼ 7) were carried out to determine the glycogen storage in the liver of mice infected with Ad-null or Ad-378. Representative results of PAS staining were shown (j). Scale bar, 50 mm. The amount of glycogen was normalized based on protein weight (k). (l) The ratio of liver weight to body weight (LW/BW) was determined in mice infected with Ad-null or Ad-378 (n ¼ 10-11). (m) Liver and serum TG levels were measured in random fed state (n ¼ 10-11). (n) Representative images of H&E staining (left) and Oil-red O staining (right) of liver sections from ad libitum-fed mice infected with Ad-null (top) or Ad-378 (bottom). Scale bar, 50 mm. Image-Pro Plus was employed for quantification of lipid content. (o) Relative mRNA levels of ACC1, FASN, SCD1 and GCK in the liver of mice infected with Ad-null or Ad-378 (n ¼ 5). (p) Protein levels of ACC and FSAN were determined by western blot analysis and quantified. Each mouse received 1 Â 10 9 PFU of adenovirus. Means±s.e.m. are shown for all panels. *Po0.05 versus control; **Po0.01 versus control; ***Po0.001 versus control (Student's t-test). All experiments were repeated at least twice and representative results are shown. NATURE COMMUNICATIONS | Supplementary Information accompanies this paper at http://www.nature.com/ naturecommunications Competing financial interests: The authors declare no competing financial interests. Reprints and permission information is available online at http://npg.nature.com/ reprintsandpermissions/ How to cite this article: Liu, W. et al. Hepatic miR-378 targets p110a and controls glucose and lipid homeostasis by modulating hepatic insulin signalling. Nat. Commun. 5:5684
doi:10.1038/ncomms6684 pmid:25471065 fatcat:2iybvflsi5ewtefc5nxgfghv4e