ADD1 Single Nucleotide Polymorphisms Are Associated With Essential Hypertension Among Han and Mongolian Population in Inner Mongolia Area

Maternally Inherited Essential Hypertension May Be Associated with the Mutations in Mitochondrial tRNAGlu Gene

Background

Mitochondrial DNA (mtDNA) mutations are associated with essential hypertension (EH), but the molecular mechanism remains largely unknown.

Objective

The aim of this study is to explore the association between mtDNA mutations and EH.

Methods

Two maternally inherited families with EH are underwent clinical, genetic and biochemical assessments. mtDNA mutations are screened by PCR-Sanger sequencing and phylogenetic, and bioinformatics analyses are performed to evaluate the pathogenicity of mtDNA mutations. We also generate cytoplasmic hybrid (cybrid) cell lines to analysis mitochondrial functions.

Results

Matrilineal relatives exhibit variable degree of clinical phenotypes. Molecular analysis reveals the presence of m.A14693G and m.A14696G mutations in two pedigrees. Notably, the m.A14693G mutation occurs at position 54 in the TψC loop of tRNAGlu, a position which is critical for post-transcriptionally modification of tRNAGlu. While the m.A14696G mutation creates a novel base-pairing (51C-64G). Bioinformatic analysis shows that these mutations alter tRNAGlu secondary structure. Additionally, patients with tRNAGlu mutations exhibit markedly decreased in mtDNA copy number, mitochondrial membrane potential (MMP) and ATP, whereas the levels of reactive oxygen species (ROS) increase significantly.

Conclusion

The m.A14696G and m.A14693G mutations lead to failure in tRNAGlu metabolism and cause mitochondrial dysfunction that is responsible for EH.

Alpha-adducin 1 (rs4961) gene and its expression associated with sodium sensitivity in hypertensive patients: a cohort study in the western Ukrainian population

Objective. The aim of this study was to evaluate the association of the α-adducin-1 gene (ADD1) (Gly460Trp [rs4961]) polymorphism and its expression in association with renal dysfunction and sodium sensitivity in hypertensive patients in western Ukrainian population. Methods. One-hundred patients with essential arterial hypertension (EAH) and hypertensive-mediated target organ damage (stage 2), moderate, high, and very high cardiovascular risk were enrolled in case-control study. Sixty healthy individuals were assigned as controls. Sodium sensitivity and sodium resistance were determined by salt load reaction. The ADD1 (rs4961) genotyping was performed in RT-PCR. Results. The expression of the quantitative trait loci (eQTL) of ADD1 gene (rs4961) (chr4:2906707 [hg19]) was confirmed in 37 tissues and organs with 23 phenotypic traits. Two hundred eQTL associations revealed - all cis-variants (cis-QTL); 73 methylation QTL (mQTL), 34 splicing QTL (sQTL), 14 histone modification QTL (hQTL), 2 protein QTL (pQTL), 23 transcript utilization QTL (tuQTL), and 4 loci of incorporated long noncoding areas of RNA (lncRNA). GG-genotype unreliably enhances EAH risk (OR=1.92; 95%CI: 0.90-4.10; p=0.066). Sodium sensitivity was observed in 54.0% of patients and in 20.0% of controls (c2=17.89; p<0.001). Sodium sensitivity in T-allele carriers of the ADD1 gene (1378G>T; rs4961) dominated 12-fold in general (OR 95%CI: 2.24-64.29; p=0.001), in women - 4.71 times (OR 95%CI: 1.92-11.56; p<0.001), and in men - 4.09 times (OR 95%CI: 1.03-16.28; p=0.041). Sodium sensitivity elevated the likelihood of severe EAH twice (OR=2.19; OR 95%CI: 1.00-5.05; p=0.049). Conclusion. T-allele associates with sodium sensitivity in essential arterial hypertension patients and increases the risk of hypertension regardless the gender. Sodium sensitivity enhances the probability of severe essential arterial hypertension in observed population.