Dataset Information

Global gene expression profiling in PPAR-γ agonist-treated kidneys in an orthologous rat model of human autosomal recessive polycystic kidney disease

ABSTRACT: Kidneys are enlarged by aberrant proliferation of tubule epithelial cells leading to the formation of numerous cysts, nephron loss, and interstitial fibrosis in polycystic kidney disease (PKD). Pioglitazone (PIO), a PPAR-γ agonist, decreased cell proliferation, interstitial fibrosis and inflammation, and ameliorated PKD progression in PCK rats. To examine the genetic mechanisms in this efficacy, we analyzed changes in global gene expression. By Gene Set Enrichment Analysis of 30655 genes, 13 of the top 20 down-regulated gene ontology biological process gene sets, and six of the top 20 curated gene set canonical pathways identified to be down-regulated by PIO-treatment were related to cell cycle and proliferation, including EGF, PDGF and JNK pathways. Their relevant pathways were identified using the Kyoto Encyclopedia of Gene and Genomes database. Stearoyl-Coenzyme A desaturase 1 is a key enzyme in fatty acid metabolism found in the top 5 genes down-regulated by PIO treatment. Immunohistochemical analysis revealed that the gene product of this enzyme was highly expressed in PCK kidneys, and decreased by PIO. These data show that PIO alters the expression of genes involved in cell cycle progression, cell proliferation, and fatty acid metabolism.

ORGANISM(S): Rattus norvegicus

PROVIDER: GSE35167 | GEO | 2012/03/22

SECONDARY ACCESSION(S): PRJNA150801

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Project description:Kidneys are enlarged by aberrant proliferation of tubule epithelial cells leading to the formation of numerous cysts, nephron loss, and interstitial fibrosis in polycystic kidney disease (PKD). Pioglitazone (PIO), a PPAR-M-NM-3 agonist, decreased cell proliferation, interstitial fibrosis and inflammation, and ameliorated PKD progression in PCK rats. To examine the genetic mechanisms in this efficacy, we analyzed changes in global gene expression. By Gene Set Enrichment Analysis of 30655 genes, 13 of the top 20 down-regulated gene ontology biological process gene sets, and six of the top 20 curated gene set canonical pathways identified to be down-regulated by PIO-treatment were related to cell cycle and proliferation, including EGF, PDGF and JNK pathways. Their relevant pathways were identified using the Kyoto Encyclopedia of Gene and Genomes database. Stearoyl-Coenzyme A desaturase 1 is a key enzyme in fatty acid metabolism found in the top 5 genes down-regulated by PIO treatment. Immunohistochemical analysis revealed that the gene product of this enzyme was highly expressed in PCK kidneys, and decreased by PIO. These data show that PIO alters the expression of genes involved in cell cycle progression, cell proliferation, and fatty acid metabolism. RNA was extracted from kidneys of rats with or without PIO treatment using a monophasic solution of phenol/guanidine isothiocyanate and TRIzol reagent (Invitrogen Co., Carlsbad, CA, USA) in accordance with their manual, and the samples were incubated with RNase-free DNase I (Ambion, TX, USA). The quality and concentration of each sample was confirmed by spectrophotometry (NanoDropTM ND-1000; Asahi glass Co. Ltd., Tokyo, Japan). Total RNA obtained from five females were pooled in each PIO-treated or control vehicle-treated (CONT) group. Briefly, 500 ng aliquots of total RNA obtained from kidneys of three rats were labeled using an Quick Amp Labeling Kit, one-color (Agilent Technologies, Inc., Santa Clara, CA, USA) according to the manufacturerM-bM-^@M-^Ys instructions. The pooled renal RNA of PIO- or vehicle-treated rats were labeled with the Cy3-fluorescence dye. After determination of labeling efficiency, 1.65 M-NM-<g aliquots of Cy3-labeled RNA were hybridized using the Gene Expression hybridization kit (Agilent Technologies) onto Rat Oligo Microarrays (Agilent Technologies, product no. G4130A) according to the manufacturerM-bM-^@M-^Ys hybridization protocol. The microarray slides were examined with an Agilent microarray scanner and software. Data analysis was performed with Agilent Feature Extraction software (version 10.7.3.1).

Project description:Autosomal recessive polycystic kidney disease (ARPKD) is caused by mutations in the PKHD1 gene in both humans and the orthologous PCK rat model. Although ARPKD results solely from PKHD1 mutations, the disease onset and severity are highly variable, indicating that other unknown genetic risk factor(s) modify ARPKD-associated phenotypes. To identify genetic modifiers of ARPKD severity, we created two genetically distinct Pkhd1 congenic rat strains on the Fawn-Hooded Hypertensive (FHH) and the Dahl S (SS) rat backgrounds (denoted FHH.Pkhd1 and SS.Pkhd1, respectively) that harbor the PCK-derived Pkhd1 allele. The FHH.Pkhd1 and SS.Pkhd1 strains had lower renal cyst formation at 30 days-of-age (5±2% and 8±2% cystic, respectively; P<0.001) compared to the PCK kidneys (26±4% cystic), which coincided with significantly reduced kidney weights in the FHH.Pkhd1 and SS.Pkhd1. Liver cyst formation and liver weight did not differ between PCK, FHH.Pkhd1, and SS.Pkhd1. These data indicated that the PCK genome harbors genetic modifier(s) of ARPKD severity that are not present in the FHH and SS genomes. Using high density SNP array genotyping and microarray expression analysis, we identified 50 potential modifiers of ARPKD severity in the PCK rat. Of these candidates, a damaging nonsynonymous variant in Nphp4 stood out as the most likely candidate based on variant segregation, protein modeling, network analysis, and gene ontology. Nphp4 is widely associated with the autosomal recessive cilliopathy and nephronopthisis, but had not been previously implicated in the molecular or cellular pathophysiology of ARPKD. Collectively, these data provide genetic evidence of disease modifier(s) in the PCK model of ARPKD and prioritized multiple candidates, including NPHP4, for further investigation in ARPKD pathogenesis. In this study, we used microarray to analyze transcript expression in the kidneys of 30 day old SD (n=4), PCK (n=4), FHH (n=4), FHH.Pkhd1 (n=4), SS (n=4), and SS.Pkhd1 (n=4). Samples were pooled and the pooled samples were run in triplicate. The 30 day timepoint was chosen because the differences in renal cyst formation between PCK, FHH.Pkhd1, and SS.Pkhd1 were greatest at this timepoint. To account for genetic strain differences that do not contribute to ARPKD severity, gene expression of each cystic rat strain was compared to its parental strain.

Dataset Information

Global gene expression profiling in PPAR-γ agonist-treated kidneys in an orthologous rat model of human autosomal recessive polycystic kidney disease

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets