Association and interaction of -58C>T and ±9 bp polymorphisms of BDKRB2 gene causing susceptibility to essential hypertension

Investigation of candidate genes and mechanisms underlying obesity associated type 2 diabetes mellitus using bioinformatics analysis and screening of small drug molecules

BACKGROUND

Obesity associated type 2 diabetes mellitus is a metabolic disorder ; however, the etiology of obesity associated type 2 diabetes mellitus remains largely unknown. There is an urgent need to further broaden the understanding of the molecular mechanism associated in obesity associated type 2 diabetes mellitus.

METHODS

To screen the differentially expressed genes (DEGs) that might play essential roles in obesity associated type 2 diabetes mellitus, the publicly available expression profiling by high throughput sequencing data (GSE143319) was downloaded and screened for DEGs. Then, Gene Ontology (GO) and REACTOME pathway enrichment analysis were performed. The protein - protein interaction network, miRNA - target genes regulatory network and TF-target gene regulatory network were constructed and analyzed for identification of hub and target genes. The hub genes were validated by receiver operating characteristic (ROC) curve analysis and RT- PCR analysis. Finally, a molecular docking study was performed on over expressed proteins to predict the target small drug molecules.

RESULTS

A total of 820 DEGs were identified between healthy obese and metabolically unhealthy obese, among 409 up regulated and 411 down regulated genes. The GO enrichment analysis results showed that these DEGs were significantly enriched in ion transmembrane transport, intrinsic component of plasma membrane, transferase activity, transferring phosphorus-containing groups, cell adhesion, integral component of plasma membrane and signaling receptor binding, whereas, the REACTOME pathway enrichment analysis results showed that these DEGs were significantly enriched in integration of energy metabolism and extracellular matrix organization. The hub genes CEBPD, TP73, ESR2, TAB1, MAP 3K5, FN1, UBD, RUNX1, PIK3R2 and TNF, which might play an essential role in obesity associated type 2 diabetes mellitus was further screened.

CONCLUSIONS

The present study could deepen the understanding of the molecular mechanism of obesity associated type 2 diabetes mellitus, which could be useful in developing therapeutic targets for obesity associated type 2 diabetes mellitus.

Genetics of Human Primary Hypertension: Focus on Hormonal Mechanisms

Increasingly, primary hypertension is being considered a syndrome and not a disease, with the individual causes (diseases) having a common sign-an elevated blood pressure. To determine these causes, genetic tools are increasingly employed. This review identified 62 proposed genes. However, only 21 of them met our inclusion criteria: (i) primary hypertension, (ii) two or more supporting cohorts from different publications or within a single publication or one supporting cohort with a confirmatory genetically modified animal study, and (iii) 600 or more subjects in the primary cohort; when including our exclusion criteria: (i) meta-analyses or reviews, (ii) secondary and monogenic hypertension, (iii) only hypertensive complications, (iv) genes related to blood pressure but not hypertension per se, (v) nonsupporting studies more common than supporting ones, and (vi) studies that did not perform a Bonferroni or similar multiassessment correction. These 21 genes were organized in a four-tiered structure: distant phenotype (hypertension); intermediate phenotype [salt-sensitive (18) or salt-resistant (0)]; subintermediate phenotypes under salt-sensitive hypertension [normal renin (4), low renin (8), and unclassified renin (6)]; and proximate phenotypes (specific genetically driven hypertensive subgroup). Many proximate hypertensive phenotypes had a substantial endocrine component. In conclusion, primary hypertension is a syndrome; many proposed genes are likely to be false positives; and deep phenotyping will be required to determine the utility of genetics in the treatment of hypertension. However, to date, the positive genes are associated with nearly 50% of primary hypertensives, suggesting that in the near term precise, mechanistically driven treatment and prevention strategies for the specific primary hypertension subgroups are feasible.

Impact of interactions between risk alleles on clinical endpoints in hypertension

OBJECTIVE

Impairment of the renin-angiotensinogen-aldosterone system (RAAS), one of the characteristics of essential hypertension (EH), imbalances vascular homeostasis. Despite inconsistent reports on individual single nucleotide polymorphisms (SNPs) as a major predictor of EH, interactions among RAAS genetic variants are rarely investigated.

METHODS

Using SNP markers, we studied potential interactions between angiotensin 1 converting enzyme (ACE), angiotensinogen (AGT), angiotensin II-type 1 receptor (AGTR1), and α adducin (ADD1) variants and their correlation with clinical endpoints in 545 individuals with hypertension and 400 age- and ethnicity-matched unrelated controls. Generalised multifactor dimensionality reduction (GMDR) analysis identified the models for genotype interaction.

RESULTS

Although the results on single genes were significant, gene-gene interactions were more reliable and promising as markers in predisposing hypertension. The best models to represent association of multi-locus interactions with augmented hypertension susceptibility were: (a) within gene 4-locus model comprised of AGT SNPs -217G/A, -20A/C, -6G/A and 235M/T (p=0.022, OR 6.1); and (b) between genes 5-locus model comprised of AGT -217G/A, -20A/C, -6G/A, 235M/T and ACE I/D (p=0.05, OR 4.6). Stratification of 4- and 5-locus GMDR models on the basis of risk alleles from ≤1 to ≥7 increased the ORs from 2.8 to 36.1 and from 0.9 to 16.1, respectively. Moreover, compared to ≤1 risk alleles the ≥7 interacting risk alleles in both 4- and 5-locus models showed an increment of 14.2% and 11.1% in systolic blood pressure, 7.7% and 1.1% in diastolic blood pressure, and 10.5% and 5.1% in mean arterial pressure, respectively, in patients.

CONCLUSIONS

Interactions among the genetic loci of RAAS components may be used as a predictor for susceptibility to hypertension.

Risk of bradykinin B2 receptor -58T/C gene polymorphism on hypertension: A meta-analysis

The risk of bradykinin B2 receptor (BDKRB2)-58T/C gene polymorphism on hypertension remains controversial. The Cochrane Library, Chinese Biomedical Database, EBSCO, Embase, ISI, MEDLINE, and PubMed were retrieved, and relevant articles were selected. The significant association between BDKRB2 -58T/C gene polymorphism and risk of hypertension were found under C-allele comparison (odds ratio (OR): 1.22, 95% confidential intervals (CI): 1.05-1.42), recessive model (OR: 1.32, 95% CI: 1.07-1.64), dominant model (OR: 0.74, 95% CI: 0.58-0.94), homozygote model (OR: 1.66, 95% CI: 1.11-2.47) and heterozygote model (OR: 1.23, 95% CI: 1.06-1.43). The magnitude of the association between the BDKRB2-58T/C gene polymorphism and risk of hypertension was substantiated in Asians under C-allele comparison (OR: 1.24, 95% CI: 1.04-1.49), recessive model (OR: 1.39, 95% CI: 1.04-1.86), dominant model (OR: 0.72, 95% CI: 0.56-0.93), homozygote model (OR: 1.78, 95% CI: 1.09-2.90) and heterozygote model (OR: 1.26, 95% CI: 1.07-1.49). No publication bias was found in the meta-analysis. The meta-analysis suggested -58C allele and -58CC genotype increase the risk of hypertension in Asians and African-Americans. Inversely, -58TT genotype decreases the risk of hypertension in Asians and African-Americans.

Association of the bradykinin receptors genes variants with hypertension: a case-control study and meta-analysis

BACKGROUND

The present study was to investigate the role of bradykinin receptors genes polymorphisms on hypertension risk in Northern Han Chinese population. We also carried out a meta-analysis on Chinese to derive a more full assessment of this association.

METHODS AND RESULTS

A total of 976 subjects from Northern Han Chinese and 7 studies with 1599 cases and 1425 controls were included in this case-control study and in the current meta-analysis, respectively. For the case-control study, we identified the genotypes of -58T/C and 1098A/G polymorphism in BDKRB2 and BDKRB1 genes, respectively, by TaqMan PCR method. Overall, we found significant association between the -58T/C polymorphism and the increased risk of hypertension in the allele comparison (p = 0.01, OR = 1.386, 95% CI [1.138-1.688]). Subgroup analysis by gender suggested that this obvious association could still be found in males, but not in females. For the 1098A/G polymorphism, no significant association was revealed in overall and subgroup analysis. For the meta-analysis involving the -58T/C polymorphism, a significant association between this polymorphism and hypertension was observed in the whole group. In Chinese Han subgroup, we found significant association with hypertension in allele comparison(C vs. T: p = 0.03, OR = 1.28, 95% CI 1.03-1.59, pheterogeneity = 0.05).

CONCLUSIONS

Our case-control study indicated that -58T/C might be significantly associated with the increased risk of hypertension in Northern Han Chinese population, which was partially confirmed by our meta-analysis.

Genetic manipulation and genetic variation of the kallikrein-kinin system: impact on cardiovascular and renal diseases

Genetic manipulation of the kallikrein-kinin system (KKS) in mice, with either gain or loss of function, and study of human genetic variability in KKS components which has been well documented at the phenotypic and genomic level, have allowed recognizing the physiological role of KKS in health and in disease. This role has been especially documented in the cardiovascular system and the kidney. Kinins are produced at slow rate in most organs in resting condition and/or inactivated quickly. Yet the KKS is involved in arterial function and in renal tubular function. In several pathological situations, kinin production increases, kinin receptor synthesis is upregulated, and kinins play an important role, whether beneficial or detrimental, in disease outcome. In the setting of ischemic, diabetic or hemodynamic aggression, kinin release by tissue kallikrein protects against organ damage, through B2 and/or B1 bradykinin receptor activation, depending on organ and disease. This has been well documented for the ischemic or diabetic heart, kidney and skeletal muscle, where KKS activity reduces oxidative stress, limits necrosis or fibrosis and promotes angiogenesis. On the other hand, in some pathological situations where plasma prekallikrein is inappropriately activated, excess kinin release in local or systemic circulation is detrimental, through oedema or hypotension. Putative therapeutic application of these clinical and experimental findings through current pharmacological development is discussed in the chapter.