Circulating let-7g-5p and miR-191-5p Are Independent Predictors of Chronic Kidney Disease in Hypertensive Patients

Abstract

Background: Hypertension (HTN) is associated with target organ damage such as cardiac, vascular, and kidney injury. Several studies have investigated circulating microRNAs (miRNAs) as biomarkers of cardiovascular disease, but few have examined them as biomarker of target organ damage in HTN. We aimed to identify circulating miRNAs that could serve as biomarkers of HTN-induced target organ damage using an unbiased approach.

Methods and results: Fifteen normotensive subjects, 16 patients with HTN, 15 with HTN associated with other features of the metabolic syndrome (MetS), and 16 with HTN or chronic kidney disease (CKD) were studied. Circulating RNA extracted from platelet-poor plasma was used for small RNA sequencing. Differentially expressed (DE) genes were identified with a threshold of false discovery rate <0.1. DE miRNAs were identified uniquely associated with HTN, MetS, or CKD. However, only 2 downregulated DE miRNAs (let-7g-5p and miR-191-5p) could be validated by reverse transcription-quantitative PCR. Let-7g-5p was associated with large vessel stiffening, miR-191-5p with MetS, and both miRNAs with estimated glomerular filtration rate (eGFR) and neutrophil and lymphocyte fraction or number and neutrophil-to-lymphocyte ratio. Using the whole population, stepwise multiple linear regression generated a model showing that let-7g-5p, miR-191-5p, and urinary albumin/creatinine ratio predicted eGFR with an adjusted R2 of 0.46 (P = 8.5e-7).

Conclusions: We identified decreased circulating let-7g-5p and miR-191-5p as independent biomarkers of CKD among patients with HTN, which could have pathophysiological and therapeutic implications.

Keywords: biomarker; blood pressure; hypertension; microRNA; target organ damage.

Figure 1.

Circulating let-7g-5p and miR-191-5p are decreased in chronic kidney disease (CKD) patients, and let-7g-5p, miR-191-5p, and urinary albumin/creatinine ratio (UACR) are independent predictors of the estimated glomerular filtration rate (eGFR). (a) Two of the top 11 most abundant differentially expressed microRNAs were validated by reverse transcription-quantitative PCR (RT-qPCR). RNA sequencing (RNA-seq) data are presented in the left panels and the RT-qPCR data in the right panels. Means ± SD and individual value of the normotensive subjects (NTN), and patients with hypertension (HTN) associated or not with other features of the metabolic syndrome (MetS) or with CKD are presented, n = 13–15 for RNA-seq data and 12–14 for RT-qPCR data. The geometric mean of miR-92b-3p, let-7f-5p, and miR-126-5p was used for normalization of RT-qPCR results. RNA-seq data were analyzed using an analysis of variance (ANOVA) one-way like test in EdgeR based on generalized linear models with a threshold of false discovery rate (q) <0.1. RT-qPCR log₂ fold change data were analyzed using one-way ANOVA followed by a Student–Newman–Keuls post hoc test with a threshold of P < 0.05. *q < 0.1, **q < 0.05, and ^†P < 0.05 vs. NTN. (b) Stepwise multiple linear regression was used to determine the best model to predict the eGFR using the let-7g-5p and miR-191-5p log₂ fold change determined by RT-qPCR and clinical parameters (age, UACR, carotid distensibility, neutrophil and lymphocyte fractions, neutrophil number, and neutrophil-to-lymphocyte ratio) that are correlated with eGFR. The best model of 3 is shown that included let-7g-5p (P = 0.001), UACR (P = 0.006), and miR-191-5p (P = 0.014). n = 49.