Association study between hypertension and A/G polymorphism at codon 637 of the transporter associated with antigen processing 1 gene

Mitochondrial related variants associated with cardiovascular traits

Introduction

Cardiovascular disease (CVD) is responsible for over 30% of mortality worldwide. CVD arises from the complex influence of molecular, clinical, social, and environmental factors. Despite the growing number of autosomal genetic variants contributing to CVD, the cause of most CVDs is still unclear. Mitochondria are crucial in the pathophysiology, development and progression of CVDs; the impact of mitochondrial DNA (mtDNA) variants and mitochondrial haplogroups in the context of CVD has recently been highlighted.

Aims

We investigated the role of genetic variants in both mtDNA and nuclear-encoded mitochondrial genes (NEMG) in CVD, including coronary artery disease (CAD), hypertension, and serum lipids in the UK Biobank, with sub-group analysis for diabetes.

Methods

We investigated 371,542 variants in 2,527 NEMG, along with 192 variants in 32 mitochondrial genes in 381,994 participants of the UK Biobank, stratifying by presence of diabetes.

Results

Mitochondrial variants showed associations with CVD, hypertension, and serum lipids. Mitochondrial haplogroup J was associated with CAD and serum lipids, whereas mitochondrial haplogroups T and U were associated with CVD. Among NEMG, variants within Nitric Oxide Synthase 3 (NOS3) showed associations with CVD, CAD, hypertension, as well as diastolic and systolic blood pressure. We also identified Translocase Of Outer Mitochondrial Membrane 40 (TOMM40) variants associated with CAD; Solute carrier family 22 member 2 (SLC22A2) variants associated with CAD and CVD; and HLA-DQA1 variants associated with hypertension. Variants within these three genes were also associated with serum lipids.

Conclusion

Our study demonstrates the relevance of mitochondrial related variants in the context of CVD. We have linked mitochondrial haplogroup U to CVD, confirmed association of mitochondrial haplogroups J and T with CVD and proposed new markers of hypertension and serum lipids in the context of diabetes. We have also evidenced connections between the etiological pathways underlying CVDs, blood pressure and serum lipids, placing NOS3, SLC22A2, TOMM40 and HLA-DQA1 genes as common nexuses.

Transporter Associated with Antigen Processing 1 Gene Polymorphisms Increase the Susceptibility to Tuberculosis

Purpose

Tuberculosis (TB) is known to result from a complex interaction between the host immune response and Mycobacterium infection. The transporter associated with antigen processing (TAP) plays an important role in the processing and presentation pathways for the Mycobacterium tuberculosis (M. tb) antigen. To investigate the possible association of the TAP1 and TAP2 genes with TB.

Patients and Methods

A total of 449 TB patients and 435 control subjects were included in this study, and single nucleotide polymorphisms (SNPs) in the TAP gene, as well as TAP1 and TAP2 alleles, were genotyped.

Results

TAP gene association analysis of TB diseases showed that rs41551515-T in the TAP1 gene was significantly associated with susceptibility to TB (P=7.96E-04, OR=4.124, 95% CI: 1.683-10.102), especially pulmonary TB (PTB, P=6.84E-04, OR=4.350, 95% CI: 1.727-10.945), and the combination of rs1057141-T-rs1135216-C in the TAP1 gene significantly increased the risk of TB susceptibility (P=5.51E-05, OR=10.899, 95% CI: 2.555-46.493). Five novel TAP1 alleles were detected in Yunnan Han people, and the allele frequency of TAP1*unknown_3 (rs41555220-rs41549617-rs1057141-rs1135216-rs1057149-rs41551515: C-A-T-C-C-T) was notably increased in all TB patients, including in the PTB and EPTB subgroups, and was significantly associated with the risk of susceptibility to TB. However, no association between the TAP2 gene and TB was found in this study.

Conclusion

Host genetic variants of rs41551515-T and the combination rs1057141-T-rs1135216-C, as well as TAP1*unknown_3 may play a critical role in susceptibility to TB disease.

Association of TAP 1 and 2 gene polymorphisms with human immunodeficiency virus-tuberculosis co-infection

Major histocompatibility complex (MHC) class I binding peptides are carried from cytosol to the lumen of the endoplasmic reticulum (ER) by transporter associated with antigen processing (TAP), an integral ER membrane protein composed of two subunits, TAP1 and TAP2. Polymorphism in TAP genes may influence these proteins further affecting the antigen peptide presentation, indirectly resulting in the viral escape mechanism from cell-mediated immunity in human immunodeficiency virus (HIV). Our aim was to study the influence of these polymorphism in study groups with HIV-tuberculosis (TB) (n = 110), TB (n = 105), and HIV (n = 130) compared with healthy controls (n = 183), using the tetraprimer amplification refractory mutation system (ARMS)-polymerase chain reaction method. Our results demonstrated that the GG genotype at TAP1 position 333 and GA genotype at TAP1 position 637 were positively associated with HIV-TB co-infection and these genotypes may act as a risk factor for developing TB co-infection in HIV-positive individuals.