Abstract: FR-PO611

Transcriptional Regulation of Long Non-Coding RNA Tug1 in Diabetic Nephropathy

Session Information

Category: Diabetes

  • 501 Diabetes Mellitus and Obesity: Basic - Experimental

Authors

  • Long, Jianyin, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States
  • Danesh, Farhad R., The University of Texas MD Anderson Cancer Center, Houston, Texas, United States
Background

Long non-coding RNAs (lncRNAs) have been implicated in the pathogenesis of a myriad of diseases, including cancer, heart diseases and kidney diseases. We recently reported that lncRNA Tug1 (Taurine-upregulated gene-1) is a differentially repressed lncRNA in a mouse model of diabetic nephropathy (DN), and podocyte-specific Tug1 overexpression exerts a renoprotective phenotype. However, how the expression of Tug1 is regulated in the diabetic milieu is unknown.

Methods

Transcription factor binding prediction algorithms (rVista 2.0 and PROMO) were used to analyze Tug1 proximal promoter region. Standard PCR, site-directed mutagenesis techniques were used to generate mouse Tug1 promoter constructs. ChIP-qPCR, eletromobility shift assays (EMSA) and luciferase reporter assays were used to identify the elements responsible for glucose and/or TGF-β1-mediated transcriptional repression of Tug1.

Results

We have generated a series of Tug1 promoter reporter constructs which were used to study the transcriptional regulation of Tug1 by high glucose and TGF-β1 signaling. Bioinformatics analysis revealed several glucose responsive elements in the highly evolutionarily conserved 1kb Tug1 promoter fragment immediately upstream of the Tug1 TSS (transcription start site). Specifically, a consensus ChoRE (carbohydrate response element) motif (CAYGYGnnnnnCRCRTG), was identified in the proximal promoter region (CACGTGACCGGATCTTG, -324 to -307) of Tug1. This motif was reported as a specific peak in our recent publication about genome-wide ChIP-Seq of the glucose-responsive transcription factor ChREBP (carbohydrate response element–binding protein, also known as MLXIPL, MLX Interacting Protein Like) in mouse liver and fat. Binding of ChREBP to this motif in podocytes was further validated by ChIP-qPCR and EMSA. We are currently identifying the cofactors/corepressors for this ChREBP-mediated repression of Tug1 in podocytes.

Conclusion

We identified glucose-responsive transcription factor ChREBP binding to the evolutional conserved ChoRE in the proximal promoter, as the mechanism of Tug1 down-regulaton in diabetic milieu.

Funding

  • NIDDK Support