Epigenetic modification of TLE1 induce abnormal differentiation in diabetic mice intestinal epithelium.

The intestinal epithelium cells (IECs) in diabetes mellitus (DM) patients have been proven to be abnormally differentiated. During the differentiation of IECs, epigenetic modification acts as an important regulator. In this study, we aimed to examine the epigenetic alteration of Transducin-like Enhancer of Split 1 (TLE1), a multitask transcriptional co-repressor, contributing to the differentiation homeostasis in IECs of DM mice. The IECs of type 2 diabetic mice model were isolated and collected. Methylation states of whole genomic DNA promoter regions were investigated by microarray. Methylated-specific PCR was used to detect the methylation state of TLE1 promoter in DM mice IECs. The expression of TLE1, Hes1, and differentiated cell markers were measured through real-time PCR, Western blots, and immunohistochemistry; by transfection assay, TLE1 or Hes1 was independently down-regulated in intestinal epithelium cell line, IEC-6. Subsequent modulation on TLE1, Hes1, and differentiated intestinal cell markers were detected. Global gene promoter regions in DM intestinal epithelium were less methylated comparing to normal control. The expression of TLE1 was significantly increased via hypomethylated activation in DM mice IECs. Hes1 was significantly suppressed and the terminal cell markers abnormally expressed in DM mice IECs (P < 0.05). Inhibition or induction on the abundance of TLE1 in IEC-6 cell line resulted in the corresponding dysregulation of Hes1 and intestinal epithelium differentiation (P < 0.05). Demethylation of TLE1 promoter region activates the self-expression in diabetic mice IECs. Subsequently, TLE1, through the transcriptional suppression on expression of Hes1, contributes to the aberrant differentiation of IECs in DM mice.