Authors: M Y Kim S H Jo J M Park T H Kim S S Im Y H Ahn
Publish Date: 2012/12/27
Volume: 56, Issue: 3, Pages: 635-643
Abstract
Transcription factor E3 TFE3 has been shown to increase insulin sensitivity by activating insulinsignalling pathways However the role of TFE3 in glucose homeostasis is not fully understood Here we explored the possible therapeutic potential of TFE3 for the control of hyperglycaemia using a streptozotocininduced mouse model of diabetesWe achieved overabundance of TFE3 in streptozotocin mice by administering an adenovirus Ad or adenoassociated virus serotype 2 AAV2 We also performed an oral glucose tolerance test OGTT and insulin tolerance test ITT To explore molecular mechanisms of blood glucose control by TFE3 transcriptional studies on the regulation of genes involved in hepatic glucose metabolism were performed using quantitative realtime PCR and chromatin immunoprecipitation assay The binding site of TFE3 in the liver Gck gene promoter was identified using deletion and sitespecific mutation studiesOverabundance of TFE3 resulted in reduced hyperglycaemia as shown by the OGTT and ITT in streptozotocintreated mice We observed that TFE3 can upregulate Gck in a state of insulin deficiency However glucose6phosphatase and cytosolic phosphoenolpyruvate carboxykinase mRNA levels were decreased by Admediated overexpression of Tcfe3 Biochemical studies revealed that the antihyperglycaemic effect of TFE3 is due to the upregulation of Gck In primary cultured hepatocytes TFE3 increased expression of Gck mRNA Conversely small interfering RNAmediated knockdown of TFE3 resulted in a decrease in Gck mRNA
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