Angiotensinogen Gene Missense Polymorphisms (rs699 and rs4762): The Association of End-Stage Renal Failure Risk with Type 2 Diabetes and Hypertension in Egyptians

Association of rs5051 and rs699 polymorphisms in angiotensinogen with coronary artery disease in Iranian population: A case-control study

Coronary artery disease (CAD) is the third most common cause of mortality globally (with 17.8 million deaths annually). Angiotensinogen (AGT) and polymorphisms in this gene can be considered as susceptibility factors for CAD. We performed a retrospective case-control study to determine the correlation of AGT rs5051 and rs699 polymorphisms with CAD in an Iranian population. We genotyped 310 CAD patients and 310 healthy subjects using polymerase chain reaction-based methods. To confirm the accuracy of the screening approach, 10% of genotyped subjects were validated using gold-standard Sanger Sequencing. To evaluate the effect of the candidate polymorphisms, white blood cells were randomly purified from the subjects and AGT expression was measured by quantitative reverse transcriptase-polymerase chain reaction. Sex stratification indicated a significant correlation between CAD and male sex (P = .0101). We found a significant association between the rs5051 A allele (P = .002) and the rs699 C allele, and CAD (P = .0122) in recessive and dominant models. Moreover, our findings showed a significant association of the haplotype, including the rs5051 A/A and rs699 T/C genotypes, with CAD (P = .0405). Finally, AGT mRNA levels were significantly decreased in patients harboring the candidate polymorphisms (P = .03). According to our findings The AGT rs5051 A and AGT rs699 C alleles are predisposing variants of CAD risk and severity in the Iranian population.

Tetra-ARMS-PCR assay development for genotyping of AGT rs699 T/C polymorphism, its comparison with PCR-RFLP and application in a case-control association study of cardiovascular disease patients

Genetic variations in the AGT gene play a significant role in controlling the plasma concentration of angiotensinogen (precursor protein of bioactive octapeptide angiotensin II) and the efficacy of antihypertensive drugs. In the current study, Tetra-Amplification Refractory Mutation System-Polymerase Chain Reaction (T-ARMS-PCR) was developed for genotyping of AGT rs699 T/C polymorphism and validated through Sanger DNA sequencing. Its efficiency was also tested using 474 human DNA samples [control, n = 181; cardiovascular disease (CVD) patients, n = 293]. Results showed that T-ARMS-PCR is superior to the commonly used PCR-Restriction Fragment Length Polymorphism (PCR-RFLP). Statistical analysis revealed that the AGT rs699 CC genotype is more prevalent in the CVD patient group (37% vs. 28%) and AGT rs699 C allele and CC genotype increased the risk of CVD by 1.4 and 1.9 fold, respectively. In summary, T-ARMS-PCR is the most suitable approach for quick and efficient genotyping of AGT rs699 T/C polymorphism in a large population in resource-limited countries, Furthermore, AGT rs699 T/C polymorphism is associated with the risk of CVD in the Punjabi Pakistani population.

Genetic Variations in Angiotensinogen Gene and Risk of Preeclampsia: A Pilot Study

Preeclampsia (PE) is a typical hypertensive disorders of pregnancy (HDP) which can cause substantial morbidity and mortality in both pregnant women and fetuses. The renin-angiotensin system (RAS) genes are the main HDP-causing genes, and Angiotensinogen (AGT) as the initial substrate can directly reflect the activity of the entire RAS. However, the association between AGT SNPs and PE risk has rarely been confirmed. This study was carried out to determine whether AGT SNPs could affect the risk of PE in 228 cases and 358 controls. The genotyping result revealed that the AGT rs7079 TT carrier was related to increased PE risk. Further stratified analysis illustrated that the rs7079 TT genotype significantly increased the PE risk in subgroups of Age < 35, BMI < 25, Albumin (ALB) ≥ 30 and Aspartate aminotransferase (AST) < 30. These findings demonstrated that the rs7079 might be a promising candidate SNP strongly associated with PE susceptibility.

The Role of Angiotensinogen rs699 in Diabetic Nephropathy Among Type 2 Diabetes Mellitus Patients with Uncontrolled Postprandial Glucose Levels

Diabetic Nephropathy (DN) is the most common complication of Type 2 Diabetes Mellitus (T2DM), leading to the highest mortality rate of DM complications. However, its etiology is still questionable. Hyperglycemia, hypertension, and particular genetic susceptibility are associated with DN. Not all patients with uncontrolled hyperglycemia suffer DN. Thus, genetic susceptibility may be a risk factor for DN. The genetic variant of angiotensinogen rs699 is known to be associated with the risk of DN with inconsistent results between ethnicities. This study aims to reveal the correlation between the AGT rs699 with the incidence of diabetic nephropathy among type-2 diabetes mellitus patients with uncontrolled postprandial glucose levels in the Jambi Malay ethnicity. This study was observational analytic research with a cross-sectional design. It used 48 DNA samples from type-2 diabetes mellitus patients with uncontrolled postprandial glucose levels. The authors took 24 DNA samples from patients with DN and 24 without DN (as a control group). The genotyping method used ARMS-PCR specific for AGT rs699. Subjects with the CT genotype had a lower risk for diabetic nephropathy than the CC genotype, but it was not statistically significant (p=0.247; OR=0.508; 95%CI=0.160-1.607). In addition, subjects with the T allele (p=0.331; OR=0.621; 95%CI-0.237-1.630) had a lower risk for diabetic nephropathy than the C allele, but it was not statistically significant. In conclusion, Angiotensinogen rs699 is not a risk factor for diabetic nephropathy among type-2 diabetes mellitus patients with uncontrolled postprandial glucose levels in the Jambi Malay ethnicity.

Hypertension in African Populations: Review and Computational Insights

Hypertension (HTN) is a persistent public health problem affecting approximately 1.3 billion individuals globally. Treatment-resistant hypertension (TRH) is defined as high blood pressure (BP) in a hypertensive patient that remains above goal despite use of ≥3 antihypertensive agents of different classes including a diuretic. Despite a plethora of treatment options available, only 31.0% of individuals have their HTN controlled. Interindividual genetic variability to drug response might explain this disappointing outcome because of genetic polymorphisms. Additionally, the poor knowledge of pathophysiological mechanisms underlying hypertensive disease and the long-term interaction of antihypertensive drugs with blood pressure control mechanisms further aggravates the problem. Furthermore, in Africa, there is a paucity of pharmacogenomic data on the treatment of resistant hypertension. Therefore, identification of genetic signals having the potential to predict the response of a drug for a given individual in an African population has been the subject of intensive investigation. In this review, we aim to systematically extract and discuss African evidence on the genetic variation, and pharmacogenomics towards the treatment of HTN. Furthermore, in silico methods are utilized to elucidate biological processes that will aid in identifying novel drug targets for the treatment of resistant hypertension in an African population. To provide an expanded view of genetic variants associated with the development of HTN, this study was performed using publicly available databases such as PubMed, Scopus, Web of Science, African Journal Online, PharmGKB searching for relevant papers between 1984 and 2020. A total of 2784 articles were reviewed, and only 42 studies were included following the inclusion criteria. Twenty studies reported associations with HTN and genes such as AGT (rs699), ACE (rs1799752), NOS3 (rs1799983), MTHFR (rs1801133), AGTR1 (rs5186), while twenty-two studies did not show any association within the African population. Thereafter, an in silico predictive approach was utilized to identify several genes including CLCNKB, CYPB11B2, SH2B2, STK9, and TBX5 which may act as potential drug targets because they are involved in pathways known to influence blood pressure. Next, co-expressed genes were identified as they are controlled by the same transcriptional regulatory program and may potentially be more effective as multiple drug targets in the treatment regimens for HTN. Genes belonging to the co-expressed gene cluster, ACE, AGT, AGTR1, AGTR2, and NOS3 as well as CSK and ADRG1 showed enrichment of G-protein-coupled receptor activity, the classical targets of drug discovery, which mediate cellular signaling processes. The latter is of importance, as the targeting of co-regulatory gene clusters will allow for the development of more effective HTN drug targets that could decrease the prevalence of both controlled and TRH.