Differential gene expression in the kidney of sickle cell transgenic mice: upregulated genes

The S+S-Antilles transgenic mouse used in this study has renal defects similar to those seen in sickle cell anemia patients: congested glomeruli, medullary fibrosis, renal enlargement, vasoocclusion, and a urine concentrating defect. We used gene expression microarrays to identify genes highly up-regulated in the kidneys of these mice and validated their expression by real-time PCR. Kidney hypoxia, as demonstrated by the presence of deoxyhemoglobin, was detected by blood oxygen dependent magnetic resonance imaging (BOLD-MRI). Some of the up-regulated genes included cytochrome P450 4a14, glutathione-S-transferase alpha-1, mitochondrial hydroxymethylglutaryl CoA synthase, cytokine inducible SH-2 containing protein, retinol dehydrogenase type III, arginase II, glycolate oxidase, Na/K ATPase, renin-1, and alkaline phosphatase 2. An increase in enzyme activity was also demonstrated for one of the up-regulated genes (arginase II). These genes can be integrated into several different pathophysiological processes: a hypoxia cascade, a replacement cascade, or an ameliorating cascade, one or all of which may explain the phenotype of this disease. We conclude that microarray technology is a powerful tool to identify genes involved in renal disease in sickle cell anemia and that the identification of various metabolic pathways may open new avenues for therapeutic interventions.