Bioinformatic Evaluation of Transcriptional Regulation of WNT Pathway Genes with reference to Diabetic Nephropathy

Abstract

Objective.WNT/β-catenin pathway members have been implicated in interstitial fibrosis and glomerular sclerosis disease processes characteristic of diabetic nephropathy (DN), processes partly controlled by transcription factors (TFs) that bind to gene promoter regions attenuating regulation. We sought to identify predictedcis-acting transcription factor binding sites (TFBSs) overrepresented within WNT pathway members.Methods.We assessed 62 TFBS motif frequencies from the JASPAR databases in 65 WNT pathway genes.Pvalues were estimated on the hypergeometric distribution for each TF. Gene expression profiles of enriched motifs were examined in DN-related datasets to assess clinical significance.Results.Transcription factor AP-2 alpha (TFAP2A), myeloid zinc finger 1 (MZF1), and specificity protein 1 (SP1) were significantly enriched within WNT pathway genes (Pvalues < 6.83 × 10−29, 1.34 × 10−11, and 3.01 × 10−6, resp.).MZF1expression was significantly increased in DN in a whole kidney dataset (fold change = 1.16; 16% increase;P=0.03).TFAP2Aexpression was decreased in an independent dataset (fold change = −1.02;P=0.03). No differential expression ofSP1was detected.Conclusions.Three TFBS profiles are significantly enriched within WNT pathway genes highlighting the potential ofin silicoanalyses for identification of pathway regulators. Modification of TF binding may possibly limit DN progression, offering potential therapeutic benefit.