Identification of angiotensin II-responsive genes in the kidney

In order to characterize gene expression networks linked to AT1 angiotensin receptors in the kidney, we carried out genome-wide transcriptional analysis of RNA from kidneys of wild-type (WT) and AT1A receptor-deficient mice (KOs) at baseline and after 2 days of angiotensin II infusion (1 ug/kg/min), using Affymetrix GeneChip Mouse Genome 430 2.0 Arrays. At baseline, 405 genes were differentially expressed (>1.5X) between WT and KO kidneys. Of these, more than 80% were up-regulated in the KO group including genes involved in inflammation, oxidative stress, and cell proliferation. After 2 days of angiotensin II infusion in WT mice, expression of ~805 genes was altered (18% up-regulated, 82% repressed). Genes in metabolism and ion transport pathways were up-regulated while there was attenuated expression of protective genes against oxidative stress including glutathione synthetase and mitochondrial SOD2. Angiotensin II infusion has little effect on blood pressure in KOs. Nonetheless, expression of more than 250 genes was altered in kidneys from KO mice during angiotensin II infusion; 14% were up-regulated, while 86% were repressed including genes involved in immune responses, angiogenesis, and glutathione metabolism. Between WT and KO kidneys during angiotensin II infusion, 728 genes were differentially expressed; 10% were increased and 90% were decreased in the WT group. Differentially regulated pathways included those involved in ion transport, immune responses, metabolism, apoptosis, cell proliferation, and oxidative stress. This genome-wide assessment should facilitate identification of critical distal pathways linked to blood pressure regulation.

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Makhanova NA, Crowley SD, Griffiths RC, Coffman TM