Gene Expression Profiling Reveals Renin mRNA Overexpression in Human Hypertensive Kidneys and a Role for MicroRNAs

Abstract

Abstract-The kidney has long been invoked in the etiology of essential hypertension. This could involve alterations in expression of specific genes and microRNAs (miRNAs). The aim of the present study was to identify, at the transcriptome-wide level, mRNAs and miRNAs that were differentially expressed between kidneys of 15 untreated hypertensive and 7 normotensive white male subjects of white European ancestry. By microarray technology we found 14 genes and 11 miRNAs that were differentially expressed in the medulla. We then selected and confirmed by real-time quantitative PCR expression differences for NR4A1, NR4A2, NR4A3, PER1, and SIK1 mRNAs and for the miRNAs hsa-miR-638 and hsa-let-7c. Luciferase reporter gene experiments in human kidney (HEK293) cells confirmed the predicted binding of hsa-let-7c to the 3Ј untranslated region of NR4A2 mRNA. In the renal cortex we found differential expression of 46 genes and 13 miRNAs. We then confirmed expression differences for AIFM1, AMBP, APOE, CD36, EFNB1, NDUFAF1, PRDX5, REN, RENBP, SLC13A1, STX4,. Functional experiments in HEK293 cells demonstrated that hsa-miR-663 can bind to the REN and APOE 3Ј untranslated regions and can regulate REN and APOE mRNA levels, whereas hsa-miR-181a regulated REN and AIFM1 mRNA. Our data demonstrated for the first time that miRNAs can regulate renin expression. The observed downregulation of 2 miRNAs in hypertension could explain the elevation in intrarenal renin mRNA. Renin, CD36, and other mRNAs, as well as miRNAs and associated pathways identified in the present study, provide novel insights into hypertension etiology. (Hypertension. 2011;58:1093-1098.) • Online Data SupplementKey Words: microarrays Ⅲ microRNAs Ⅲ renin angiotensin system Ⅲ kidney Ⅲ hypertension S olving the molecular etiology of essential hypertension has been challenging. 1 Studies of selected blood pressure (BP) genes and large genome-wide association studies have identified only a handful of gene variants of small effect sizes. The interplay between genetic and environmental factors that contributes to the heterogeneity of hypertension has made the identification of causative alleles, genes, and transcripts difficult. 1 A further impediment has been the difficulty in obtaining suitable human tissue samples other than blood.Guyton and colleagues 2,3 theorized that hypertension is caused by a primary defect in the kidney. This idea has gained support from rare monogenic forms of hypertension, in which single mutations in genes responsible for renal sodium reabsorption 4 result in BP elevation. 3 MicroRNAs (miRNAs) are important for physiological and pathophysiological processes in various diseases. 5 These 18 to 30 nucleotides noncoding RNAs regulate the expression and translation of half of protein-coding mRNAs in humans by binding to target sites in the 3Ј untranslated region (UTR) to destabilize them or impede translation. 5 If miRNAs modulate mRNAs for BP genes, they could form the basis for novel antihypertensive therapies. 6,7 Knowledge of effects of miRNAs ...

Circulating microRNAs and hypertension—from new insights into blood pressure regulation to biomarkers of cardiovascular risk

“…[17] Importantly, binding of miR-181a to the 3'UTR of the renin gene was demonstrated using luciferase reporter assays transfected into HEK293 kidney cells. This clearly explains how miR181a may lead to decreased renin mRNA levels.…”

High intensity interval training favourably affects antioxidant and inflammation mRNA expression in early-stage chronic kidney disease

“…(Table 1 -republished with permission [19]) Tissue used for analyses were chosen based on tissue-specific transcriptomic work performed in SHRs [20]. Renal tissue specifically consisted of renal cortex as mRNA is differentially expressed dependant on the type of renal tissue [21]. Approximately 100 mg (± 10 mg) of renal tissue was homogenised in 1 ml of TRI-reagent, using the TRI-reagent method (Sigma Aldrich, St. Louis, MO, USA).…”

A Novel Interaction Between Sympathetic Overactivity and Aberrant Regulation of Renin by miR-181a in BPH/2J Genetically Hypertensive Mice

“…15 Marques et al 15 showed that hypertensive individuals have marked underexpression of miR-181a in the kidney, accompanied by marked overexpression of renin mRNA. Such a pattern was seen in BPH/2J mice in our study.…”

“…14 We also measured the micro-RNA (miRNA) miR-181a because its human homolog has been shown to negatively regulate human renin mRNA and is reduced in the kidney in human hypertension. 15 Tyrosine hydroxylase (TH) staining, a marker of sympathetic innervation, 16 was used to quantify renal innervation.…”

“…15 Tyrosine hydroxylase (TH) staining, a marker of sympathetic innervation, 16 was used to quantify renal innervation.…”