SNPs in lncRNA KCNQ1OT1 Modulate Its Expression and Confer Susceptibility to Salt Sensitivity of Blood Pressure in a Chinese Han Population

Abstract

Long noncoding RNA (lncRNA) plays an important role in cardiovascular diseases, but the involvement of lncRNA in salt sensitivity of blood pressure (SSBP) is not well-known. We aimed to explore the association of sixteen single-nucleotide polymorphisms (SNPs) in five lncRNA genes (KCNQOT1, lnc-AGAP1-8:1, lnc-IGSF3-1:1, etc.) with their expression and susceptibility to SSBP. A two-stage association study was conducted among 2057 individuals. Quantified expression of the lncRNA was detected using real-time PCR. Genotyping was accomplished using the MassARRAY System. The expression quantitative tra2it loci test and the generalized linear model were utilized to explore the function of SNPs. One-sample Mendelian randomization was used to study the causal relationship between KCNQOT1 and SSBP. Significant effects were observed in KCNQ1OT1 expressions on the SSBP phenotype (p < 0.05). Rs10832417 and rs3782064 in KCNQ1OT1 may influence the secondary structure, miRNA binding, and expression of KCNQ1OT1. Rs10832417 and rs3782064 in KCNQ1OT1 were identified to be associated with one SSBP phenotype after multiple testing corrections and may be mediated by KCNQ1OT1. One-sample Mendelian randomization analyses showed a causal association between KCNQ1OT1 and SSBP. Our findings suggest that rs10832417 and rs3782064 might be associated with a lower risk of SSBP through influencing the KCNQ1OT1 secondary structure and miRNA binding, resulting in changes in KCNQ1OT1 expression.

Keywords: acute salt loading; blood pressure; lncRNA; salt sensitivity; single-nucleotide polymorphism.

Figure 1

Flow chart for two-stage analysis. The workflow of the analysis includes the screening criteria and the methods. SS, salt sensitivity; SSBP, salt sensitivity of blood pressure; SNP, single-nucleotide polymorphism; MAF, minor allele frequency; HWE, Hardy–Weinberg equilibrium; LD, linkage disequilibrium; eQTL, expression quantitative trait loci.

Figure 2

Linear regression analysis representing the association of lncRNAs with SSBP.

Figure 3

Comparison of SNP alleles regarding lncRNA KCNQ1OT1 expression level. * p < 0.05; ** p < 0.01; *** p < 0.001.

Figure 4

Minimum Free Energy (MFE) structure of the KCNQ1OT1. We used RNAfold. The predicted folding structures and MFE with (A) rs10832417 g or rs10832417-T; (B) rs3782064-A or rs3782064-G; (C) rs58956504-C or rs58956504-T; (D) rs11023582-A or rs11023582-G; (E) rs12577654-C or rs12577654-T. The structure is colored by base-pairing probabilities. For unpaired regions the color denotes the probability of being unpaired.

Figure 5

Association of observationally and genetically determined lncRNA KCNQ1OT1 and SSBP. Observational analyses used multiple linear regression multivariable adjusted for age and gender. One-sample Mendelian randomization analyses used instrumental variable analyses with two-stage least-squares regression.