KLF3 impacts insulin sensitivity and glucose uptake in skeletal muscle

Skeletal muscle is one of the predominant sites involved in glucose disposal, accounting for ∼80% of postprandial glucose uptake, and plays a critical role in maintaining glycemic homeostasis. Dysregulation of energy metabolism in skeletal muscle is involved in developing insulin resistance and type 2 diabetes (T2D). Transcriptomic responses of skeletal muscle to exercise found that the expression of <i>Klf3</i> was increased in T2D Goto-Kakizaki (GK) rats and decreased after exercise with improved hyperglycemia and insulin resistance, implying that <i>Klf3</i> might be associated with insulin sensitivity and glucose metabolism. We also found that knockdown of <i>Klf3</i> promoted basal and insulin-stimulated glucose uptake in L6 myotubes, whereas overexpression of <i>Klf3</i> resulted in the opposite. Through pairwise comparisons of L6 myotubes transcriptome, we identified 2,256 and 1,988 differentially expressed genes in <i>Klf3</i> knockdown and overexpression groups, respectively. In insulin signaling, the expression of <i>Slc2a4</i>, <i>Akt2</i>, <i>Insr</i>, and <i>Sorbs1</i> was significantly increased by <i>Klf3</i> knockdown and decreased with <i>Klf3</i> overexpression; <i>Ptprf</i> and <i>Fasn</i> were markedly downregulated in <i>Klf3</i> reduced group and upregulated in <i>Klf3</i> overexpressed group. Moreover, downregulation of <i>Klf3</i> promoted the expression of glucose transporter 4 (GLUT4) and protein kinase B (AKT) proteins, as well as the translocation of GLUT4 to the cell membrane in the basal situation, and enhanced insulin sensitivity, characterized by increased insulin-stimulated GLUT4 translocation and AKT, TBC1 domain family member 1 (TBC1D1) and TBC1 domain family member 4 (TBC1D4) phosphorylation, whereas overexpression of <i>Klf3</i> showed contrary results. These results suggest that <i>Klf3</i> affects glucose uptake and insulin sensitivity via insulin signal transduction and intracellular metabolism, offering a novel potential treatment strategy for T2D.<b>NEW & NOTEWORTHY</b> The knockdown of <i>Klf3</i> increased glucose uptake and improved insulin sensitivity in L6 myotubes, whereas its overexpression had the opposite effect. To explore the underlying mechanisms, we evaluated the transcriptional profiles of L6 myotubes after <i>Klf3</i> knockdown and overexpression and revealed that metabolism and insulin-related pathways were significantly impacted. <i>Klf3</i> also influenced the expression or modification of glucose transporter 4 (GLUT4), protein kinase B (AKT), TBC1 domain family member 1 (TBC1D1), and TBC1 domain family member 4 (TBC1D4) in the insulin signaling pathway, affecting insulin sensitivity and glucose uptake.