Altered metabolic gene expression in the brain of a triprolyl-human amylin transgenic mouse model of type 2 diabetes

Sci Rep. 2019 Oct 10;9(1):14588. doi: 10.1038/s41598-019-51088-x.

Abstract

Type 2 diabetes mellitus is a major health concern worldwide; however, the molecular mechanism underlying its development is poorly understood. The hormone amylin is postulated to be involved, as human amylin forms amyloid in the pancreases of diabetic patients, and oligomers have been shown to be cytotoxic to β-cells. As rodent amylin is non-amyloidogenic, mice expressing human amylin have been developed to investigate this hypothesis. However, it is not possible to differentiate the effects of amylin overexpression from β-cell loss in these models. We have developed transgenic mice that overexpress [25, 28, 29 triprolyl]human amylin, a non-amyloidogenic variant of amylin, designated the Line 44 model. This model allows us to investigate the effects of chronic overexpression of non-cytotoxic amylin. We characterised this model and found it developed obesity, hyperglycaemia and hyperinsulinaemia. This phenotype was associated with alterations in the expression of genes involved in the amylin, insulin and leptin signalling pathways within the brain. This included genes such as c-Fos (a marker of amylin activation); Socs3 (a leptin inhibitor); and Cart, Pomc and Npy (neuropeptides that control appetite). We also examined Socs3 protein expression and phosphorylated Stat3 to determine if changes at the mRNA level would be reflected at the protein level.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Glucose / analysis
  • Body Weight
  • Brain / metabolism
  • Diabetes Mellitus, Type 2 / genetics*
  • Disease Models, Animal
  • Gene Expression Profiling
  • Gene Expression Regulation*
  • Humans
  • Insulin / metabolism
  • Islet Amyloid Polypeptide / genetics*
  • Leptin / metabolism
  • Male
  • Mice
  • Mice, Transgenic
  • Nerve Tissue Proteins / metabolism
  • Neuropeptide Y / metabolism
  • Obesity
  • Phenotype
  • Phosphorylation
  • Pro-Opiomelanocortin / metabolism
  • Proto-Oncogene Proteins c-fos / metabolism
  • RNA, Messenger / metabolism
  • STAT3 Transcription Factor / metabolism
  • Signal Transduction
  • Suppressor of Cytokine Signaling 3 Protein / metabolism

Substances

  • Blood Glucose
  • Fos protein, mouse
  • Insulin
  • Islet Amyloid Polypeptide
  • Leptin
  • Nerve Tissue Proteins
  • Neuropeptide Y
  • Proto-Oncogene Proteins c-fos
  • RNA, Messenger
  • STAT3 Transcription Factor
  • Socs3 protein, mouse
  • Stat3 protein, mouse
  • Suppressor of Cytokine Signaling 3 Protein
  • cocaine- and amphetamine-regulated transcript protein
  • Pro-Opiomelanocortin