Epigallocatechin gallate induces GLUT4 translocation in skeletal muscle through both PI3K- and AMPK-dependent pathways

Food Funct. 2018 Aug 15;9(8):4223-4233. doi: 10.1039/c8fo00807h.

Abstract

Our previous report demonstrated that epigallocatechin gallate (EGCg) promotes translocation of glucose transporter 4 (GLUT4) in skeletal muscle. In this study, we investigated the molecular mechanism of GLUT4 translocation by EGCg at the physiological concentration range. In L6 cells, EGCg induced phosphorylation of phosphatidylinositide 3'-kinase (PI3K) and downstream protein kinase C (PKC) λ/ξ without affecting the phosphorylation of insulin receptor and Akt. EGCg-induced GLUT4 translocation was suppressed by RNA interference-mediated knockdown of PI3K and treatment with PKC inhibitor Go6983. Moreover, EGCg increased Rac1 activity and actin remodelling as downstream events of PKCλ/ξ. These results indicate that EGCg induced GLUT4 translocation through a PI3K-dependent pathway, but its mode of action differed from that of insulin. EGCg also induced GLUT4 translocation through a 5'-adenosine monophosphate-activated protein kinase (AMPK)-dependent pathway. 67 kDa laminin receptor, which is a target molecule of EGCg, was not involved in EGCg-induced glucose uptake in L6 cells. The oral administration of EGCg suppressed postprandial hyperglycaemia accompanied by GLUT4 translocation through both PI3K- and AMPK-dependent pathways, and promoted glycogen accumulation in skeletal muscle of ICR mice. EGCg promotes GLUT4 translocation through both PI3K- and AMPK-dependent pathways and glycogen accumulation in skeletal muscle.

MeSH terms

  • AMP-Activated Protein Kinases / genetics
  • AMP-Activated Protein Kinases / metabolism*
  • Animals
  • Catechin / analogs & derivatives*
  • Catechin / pharmacology
  • Cell Line
  • Cell Membrane
  • Gene Expression Regulation / drug effects
  • Glucose / metabolism
  • Glucose Transporter Type 4 / metabolism*
  • Insulin
  • Isoenzymes / metabolism
  • Male
  • Mice
  • Mice, Inbred ICR
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / metabolism*
  • Phosphatidylinositol 3-Kinases / genetics
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Phosphorylation
  • Protein Kinase C / metabolism
  • Protein Transport / drug effects

Substances

  • Glucose Transporter Type 4
  • Insulin
  • Isoenzymes
  • Slc2a4 protein, mouse
  • Catechin
  • epigallocatechin gallate
  • Phosphatidylinositol 3-Kinases
  • protein kinase C zeta
  • Protein Kinase C
  • protein kinase C lambda
  • AMP-Activated Protein Kinases
  • Glucose