Gene Expression Changes Induced by Unilateral Ureteral Obstruction in Mice

Department of Urology, Stanford University School of Medicine, Stanford, California 94305-5118, USA.
The Journal of urology (Impact Factor: 4.47). 07/2012; 188(3):1033-41. DOI: 10.1016/j.juro.2012.05.004
Source: PubMed


Loss of renal function is often the impetus for operative intervention in renal obstruction cases. Obstructive nephropathy is characterized by discrete morphological and physiological changes, including tubular dilatation, apoptosis and atrophy as well as interstitial cellular infiltration and progressive interstitial fibrosis. We hypothesized that gene expression alterations correlate with obstructive nephropathy and could serve as biomarkers for early intervention.
C57BL/6 mice were subjected to unilateral ureteral obstruction or sham surgery at postnatal day 21. Kidneys were harvested 1, 2, 5 and 9 days postoperatively. RNA was extracted from kidneys and comprehensive gene expression profiling was performed with microarrays. IPA® pathway analysis software was used to analyze the biological function and gene networks of gene expression data.
Microarray analysis revealed more than 1,800 transcripts that were up-regulated or down-regulated during days 1 through 9 after obstruction, including many previously reported transcripts (FOS, CD44, CLU, SPP1 and EGF). Pathway analysis showed significant enrichment of transcripts in cell activation/differentiation, immune/inflammatory responses, cell cycle, metabolic process and transport. Network analysis using IPA showed that transcriptional regulatory pathways involving CEBPB and HNF4A are involved in obstructive nephropathy.
This data set provides a foundation for development of biomarkers for obstructive nephropathy.

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Available from: James D Brooks, Aug 05, 2014
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    • "CD44 is one the proteins downregulated by miR-328 in human cells [20], and its expression is reported to be associated with EMT in nasopharyngeal carcinoma [40]. Wu et al. reported that UUO in mice resulted in significantly increased RNA expression of CD44 postoperatively [41]. These results inspired us to study the role of CD44 in pressure-induced EMT. "
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    ABSTRACT: Epithelial-mesenchymal transition (EMT) occurs in stressed tubular epithelial cells, contributing to renal fibrosis. Initial mechanisms promoting EMT are unknown. Pressure force is an important mechanism contributing to the induction and progression of renal fibrogenesis in ureteric obstruction. In our study of cultured rat renal tubular cells (NRK-52E) under 60 mmHg of pressure, we found that the epithelial marker E-cadherin decreased and mesenchymal markers, e.g., α-smooth muscle actin, fibronectin and Snail, increased. Pressure also induced the expression of connective tissue growth factor and transforming growth factor-β. MicroRNA array assays showed that pressure reduced miR-328 at the initial stage of pressurization. We identified a potential target sequence of miR-328 in rat CD44 3'-untranslated regions. In contrast with the miR-328 expression, CD44 expression was up-regulated at the initial pressurization stage. We also found that miR-328 expression decreased and CD44 increased in ureteric obstruction kidneys in the animal study. CD44 siRNA transfection significantly increased E-cadherin expression and inhibited pressure-induced EMT. Both hyaluronan binding peptide pep-1 and osteopontin neutralizing antibody inhibited pressure-induced EMT. Our results suggest that miR-328-mediated CD44 transient upregulation is an important trigger of the pressure-induced EMT in renal fibrosis.
    Full-text · Article · Jun 2014 · PLoS ONE