PHD3 regulates glucose metabolism by suppressing stress-induced signalling and optimising gluconeogenesis and insulin signalling in hepatocytes

Sci Rep. 2018 Sep 24;8(1):14290. doi: 10.1038/s41598-018-32575-z.

Abstract

Glucagon-mediated gene transcription in the liver is critical for maintaining glucose homeostasis. Promoting the induction of gluconeogenic genes and blocking that of insulin receptor substrate (Irs)2 in hepatocytes contributes to the pathogenesis of type 2 diabetes. However, the molecular mechanism by which glucagon signalling regulates hepatocyte metabolism is not fully understood. We previously showed that a fasting-inducible signalling module consisting of general control non-repressed protein 5, co-regulator cAMP response element-binding protein binding protein/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2, and protein kinase A is required for glucagon-induced transcription of gluconeogenic genes. The present study aimed to identify the downstream effectors of this module in hepatocytes by examining glucagon-induced potential target genes. One of these genes was prolyl hydroxylase domain (PHD)3, which suppressed stress signalling through inhibition of the IκB kinase-nuclear factor-κB pathway in a proline hydroxylase-independent manner to maintain insulin signalling. PHD3 was also required for peroxisome proliferator-activated receptor γ coactivator 1α-induced gluconeogenesis, which was dependent on proline hydroxylase activity, suggesting that PHD3 regulates metabolism in response to glucagon as well as insulin. These findings demonstrate that glucagon-inducible PHD3 regulates glucose metabolism by suppressing stress signalling and optimising gluconeogenesis and insulin signalling in hepatocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cyclic AMP / metabolism
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Enzyme Activation
  • Gene Expression Regulation
  • Glucagon / metabolism
  • Gluconeogenesis*
  • Glucose / metabolism*
  • Hepatocytes / metabolism*
  • Humans
  • Inflammation / genetics
  • Inflammation / pathology
  • Insulin / metabolism*
  • Interleukin-6 / metabolism
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Male
  • Mice, Inbred C57BL
  • Models, Biological
  • NF-kappa B / metabolism
  • Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha / metabolism
  • Procollagen-Proline Dioxygenase / genetics
  • Procollagen-Proline Dioxygenase / metabolism*
  • Prolyl Hydroxylases / metabolism
  • Repressor Proteins / metabolism
  • STAT3 Transcription Factor / metabolism
  • STAT6 Transcription Factor / metabolism
  • Signal Transduction*
  • Stress, Physiological*
  • Trans-Activators / metabolism
  • Unfolded Protein Response
  • p300-CBP Transcription Factors / metabolism

Substances

  • Cited2 protein, mouse
  • Insulin
  • Interleukin-6
  • NF-kappa B
  • Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha
  • Repressor Proteins
  • STAT3 Transcription Factor
  • STAT6 Transcription Factor
  • Trans-Activators
  • Glucagon
  • Cyclic AMP
  • Prolyl Hydroxylases
  • PHD3 protein, mouse
  • Procollagen-Proline Dioxygenase
  • p300-CBP Transcription Factors
  • p300-CBP-associated factor
  • Cyclic AMP-Dependent Protein Kinases
  • JNK Mitogen-Activated Protein Kinases
  • Glucose