A liver Hif-2α-Irs2 pathway sensitizes hepatic insulin signaling and is modulated by Vegf inhibition

Nat Med. 2013 Oct;19(10):1331-1337. doi: 10.1038/nm.3295. Epub 2013 Sep 15.

Abstract

Insulin initiates diverse hepatic metabolic responses, including gluconeogenic suppression and induction of glycogen synthesis and lipogenesis. The liver possesses a rich sinusoidal capillary network with a higher degree of hypoxia and lower gluconeogenesis in the perivenous zone as compared to the rest of the organ. Here, we show that diverse vascular endothelial growth factor (VEGF) inhibitors improved glucose tolerance in nondiabetic C57BL/6 and diabetic db/db mice, potentiating hepatic insulin signaling with lower gluconeogenic gene expression, higher glycogen storage and suppressed hepatic glucose production. VEGF inhibition induced hepatic hypoxia through sinusoidal vascular regression and sensitized liver insulin signaling through hypoxia-inducible factor-2α (Hif-2α, encoded by Epas1) stabilization. Notably, liver-specific constitutive activation of HIF-2α, but not HIF-1α, was sufficient to augment hepatic insulin signaling through direct and indirect induction of insulin receptor substrate-2 (Irs2), an essential insulin receptor adaptor protein. Further, liver Irs2 was both necessary and sufficient to mediate Hif-2α and Vegf inhibition effects on glucose tolerance and hepatic insulin signaling. These results demonstrate an unsuspected intersection between Hif-2α-mediated hypoxic signaling and hepatic insulin action through Irs2 induction, which can be co-opted by Vegf inhibitors to modulate glucose metabolism. These studies also indicate distinct roles in hepatic metabolism for Hif-1α, which promotes glycolysis, and Hif-2α, which suppresses gluconeogenesis, and suggest new treatment approaches for type 2 diabetes mellitus.

Publication types

  • Research Support, American Recovery and Reinvestment Act
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / physiology*
  • Diabetes Mellitus, Type 2 / therapy
  • Insulin / metabolism*
  • Insulin Receptor Substrate Proteins / physiology*
  • Liver / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Polymerase Chain Reaction
  • Signal Transduction*
  • Vascular Endothelial Growth Factor A / antagonists & inhibitors*

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • Insulin
  • Insulin Receptor Substrate Proteins
  • Irs2 protein, mouse
  • Vascular Endothelial Growth Factor A
  • endothelial PAS domain-containing protein 1

Associated data

  • GEO/GSE50519