A Combined Transcriptome and Bioinformatics Approach to Unilateral Ureteral Obstructive Uropathy in the Fetal Sheep Model

Purpose: Fetal obstructive uropathy is a leading cause of loss of renal function. Characterizing the molecular fingerprint of cellular responses to obstruction in a fetal model of complete unilateral ureteral obstruction may help elucidate the activated mechanisms and suggest new therapeutic interventions. Material and Methods: Unilateral ureteral obstruction was created in 3 sheep fetuses at day 60 of gestation. For transcriptome analysis total RNA was extracted from vital renal biopsies 2 weeks after intervention from obstructed kidneys and from control kidneys of untreated twins. cDNA preparation, hybridization to the GeneChip (R) Bovine Genome Array and array scanning were done according to manufacturer protocols. Bioinformatics analysis was used to derive functional biological processes linked to obstructive uropathy. Quantitative reverse-transcriptase-polymerase chain reaction and immunohistochemistry were used to validate microarray results. Results: Seven biological processes were identified as significantly affected by differentially regulated features that characterize unilateral ureteral obstruction, namely protein metabolism and modification, other metabolism, neuronal activity, ligand mediated signaling, amino acid metabolism, coenzyme/prosthetic group metabolism and rRNA metabolism. Literature mining identified 17 candidate genes previously reported as key in the context of unilateral ureteral obstruction, related pathological mechanisms or other kidney diseases. Conclusions: Combined transcriptome and bioinformatics analysis allowed the identification of enriched processes in the fetal sheep model of unilateral ureteral obstruction that are likely associated with renal damage but to our knowledge have not been previously identified. Future clarification of these molecular fingerprints may eventually provide therapeutic targets and early predictive markers involved in the pathogenesis of fetal uropathy.