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Int J Biol Sci. 2012;8(6):791-801. doi: 10.7150/ijbs.4568. Epub 2012 Jun 5.

Reduction in Tcf7l2 expression decreases diabetic susceptibility in mice.

Author information

1
Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201, USA.

Abstract

OBJECTIVE:

The WNT signaling pathway effector gene TCF7L2 has been associated with an increased risk of type 2 diabetes. However, it remains unclear how this gene affects diabetic pathogenesis. The goal of this study was to investigate the effects of Tcf7l2 haploinsufficiency on metabolic phenotypes in mice.

EXPERIMENTAL DESIGN:

Tcf7l2 knockout (Tcf7l⁻/⁻) mice were generated. Because of the early mortality of Tcf7l2⁻/⁻ mice, we characterized the metabolic phenotypes of heterozygous Tcf7l2⁺/⁻ mice in comparison to the wild-type controls. The mice were fed a normal chow diet or a high fat diet (HFD) for 9 weeks.

RESULTS:

The Tcf7l2⁺/⁻ mice showed significant differences from the wild-type mice with regards to body weight, fasting glucose and insulin levels. Tcf7l2⁺/⁻ mice displayed improved glucose tolerance. In the liver of Tcf7l2⁺/⁻ mice fed on the HFD, reduced lipogenesis and hepatic triglyceride levels were observed when compared with those of wild-type mice. Furthermore, the Tcf7l2⁺/⁻ mice fed on the HFD exhibited decreased peripheral fat deposition. Immunohistochemistry in mouse pancreatic islets showed that endogenous expression of Tcf7l2 was upregulated in the wild-type mice, but not in the Tcf7l2⁺/⁻ mice, after feeding with the HFD. However, the haploinsufficiency of Tcf7l2 in mouse pancreatic islets resulted in little changes in glucose-stimulated insulin secretion.

CONCLUSION:

These results suggest that decreased expression of Tcf7l2 confers reduction of diabetic susceptibility in mice via regulation on the metabolism of glucose and lipid.

KEYWORDS:

Tcf7l2; diabetes; gluconeogenesis; glucose tolerance; hepatic steatosis.; high fat diet

PMID:
22719219
PMCID:
PMC3372883
DOI:
10.7150/ijbs.4568
[Indexed for MEDLINE]
Free PMC Article

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