Adipocyte exosome miR-4472 inhibits glucose uptake in skeletal muscle through downregulation of MEF2D

Abstract

Aims/introduction: Previous studies have found that miR-4472 is overexpressed in the serum of individuals with obesity and type 2 diabetes mellitus (T2DM), which may participate in the process of obesity-induced T2DM. However, a role for miR-4472 in the process has not been demonstrated. Here, we aim to investigate whether the increased content of miR-4472 in adipose tissue derived from exosomes inhibits glucose uptake in skeletal muscle by downregulating the expression of its target gene. Materials and methods: In vitro C2C12 and 3T3-L1 cells, and in vivo diet-induced obesity mouse models and AT-Dicer KO mice were used to assess the impact of miR-4472 on glucose uptake and insulin sensitivity. We also evaluated the effects of serum exosomes from normal and obese individuals on insulin sensitivity in mice and the expression of miR-4472 and target genes in skeletal muscle. Results: miR-4472 exhibits a strong positive correlation with BMI, waist circumference, hip circumference, and FPG. The content of miR-4472 derived from adipose tissue exosomes increases in the circulation in a state of obesity, which can induce insulin resistance by targeting the expression of MEF2D/GLUT4, inhibiting the glucose consumption and uptake ability of skeletal muscle cells. Both exosome inhibitors and miR-4472 inhibitors can reverse the inhibitory effect of miR-4472 on MEF2D/GLUT4 expression and glucose intake and uptake ability. Additionally, they can improve insulin resistance caused by increased miR-4472 levels in mice with obesity. Conclusions: Adipocyte exosome miR-4472 inhibits glucose uptake in skeletal muscle through downregulating the expression of MEF2D/GLUT4.