Intestinal SIRT3 overexpression in mice improves whole body glucose homeostasis independent of body weight

Mol Metab. 2017 Oct;6(10):1264-1273. doi: 10.1016/j.molmet.2017.07.009. Epub 2017 Jul 18.

Abstract

Objective: Intestinal metabolism might play a greater role in regulating whole body metabolism than previously believed. We aimed to enhance enterocyte metabolism in mice and investigate if it plays a role in diet-induced obesity (DIO) and its comorbidities.

Methods: Using the cre-loxP system, we overexpressed the mitochondrial NAD+ dependent protein deacetylase SIRT3 in enterocytes of mice (iSIRT3 mice). We chronically fed iSIRT3 mice and floxed-SIRT3 control (S3fl) mice a low-fat, control diet (CD) or a high-fat diet (HFD) and then phenotyped the mice.

Results: There were no genotype differences in any of the parameters tested when the mice were fed CD. Also, iSIRT3 mice were equally susceptible to the development of DIO as S3fl mice when fed HFD. They were, however, better able than S3fl mice to regulate their blood glucose levels in response to exogenous insulin and glucose, indicating that they were protected from developing insulin resistance. This improved glucose homeostasis was accompanied by an increase in enterocyte metabolic activity and an upregulation of ketogenic gene expression in the small intestine.

Conclusion: Enhancing enterocyte oxidative metabolism can improve whole body glucose homeostasis.

Keywords: Enterocytes; Gut; Insulin resistance; Ketone bodies; Oxidative metabolism; Sirtuins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Glucose / metabolism
  • Body Weight / physiology*
  • Energy Metabolism
  • Enterocytes / enzymology
  • Enterocytes / metabolism*
  • Glucose / metabolism*
  • Glucose Intolerance / metabolism
  • Homeostasis
  • Humans
  • Insulin / metabolism
  • Insulin Resistance / physiology
  • Intestinal Mucosa / enzymology
  • Intestinal Mucosa / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Obesity / genetics
  • Obesity / metabolism
  • Sirtuin 3 / biosynthesis*
  • Sirtuin 3 / genetics
  • Sirtuin 3 / metabolism

Substances

  • Blood Glucose
  • Insulin
  • Sirt3 protein, mouse
  • Sirtuin 3
  • Glucose