A tagging SNP in ALOX5AP and risk of stroke: a haplotype-based analysis among eastern Chinese Han population

Stroke Genomics: Current Knowledge, Clinical Applications and Future Possibilities

The pathophysiology of stoke involves many complex pathways and risk factors. Though there are several ongoing studies on stroke, treatment options are limited, and the prevalence of stroke is continuing to increase. Understanding the genomic variants and biological pathways associated with stroke could offer novel therapeutic alternatives in terms of drug targets and receptor modulations for newer treatment methods. It is challenging to identify individual causative mutations in a single gene because many alleles are responsible for minor effects. Therefore, multiple factorial analyses using single nucleotide polymorphisms (SNPs) could be used to gain new insight by identifying potential genetic risk factors. There are many studies, such as Genome-Wide Association Studies (GWAS) and Phenome-Wide Association Studies (PheWAS) which have identified numerous independent loci associated with stroke, which could be instrumental in developing newer drug targets and novel therapies. Additionally, using analytical techniques, such as meta-analysis and Mendelian randomization could help in evaluating stroke risk factors and determining treatment priorities. Combining SNPs into polygenic risk scores and lifestyle risk factors could detect stroke risk at a very young age and help in administering preventive interventions.

Association between the polymorphism (rs17222919, -1316T/G) of 5-lipoxygenase-activating protein gene (ALOX5AP) and the risk of stroke: A meta analysis

BACKGROUND

The objective of this study was to evalutate the relationship between 5-lipoxygenase-activating protein gene (ALOX5AP) -rs17222919-1316T/G polymorphisms and the risk of stroke.

METHODS

Relative studies were searched in January 2018. Case-control studies with extractable data were selected. Four gene models were analyzed including, allele genetic model (G vs T), additive genetic model (GG vs TT, GT vs TT), recessive genetic model (GG vs GT + TT), and dominant genetic model (GG + GT vs TT). Effect sizes included odds ratio (OR) and 95% confidence interval (CI). Heterogeneity was assessed by using Q test and I test. Publication bias was evaluated by using Egger method. The reliability of the results was assessed with sensitivity analysis. All the data analysis was performed with R 3.10 software.

RESULTS

A total of 5 studies inclusing 8492 patients were included. There were significant relationship between ALOX5AP-rs17222919-1316T/G polymorphisms and stroke under all models (P < .05) except the additive genetic model GT versus TT (P > .05). No publication bias was noted. Sensitivity analysis indicated that the results were not stable.

CONCLUSION

This meta-analysis indicates that ALOX5AP-rs17222919-1316T/G may be a protective factor aginst stroke.

Lipoprotein lipase gene polymorphisms as risk factors for stroke: a computational and meta-analysis

OBJECTIVES

Stroke is the most common neurological disorder and genetic susceptibility has an important role in its etiology. Polymorphism in several genes such as lipoprotein lipase (LPL) is propounded as a risk for stroke. This meta-analysis investigated the association of rs285 and rs320 LPL polymorphism with stroke risk.

MATERIALS AND METHODS

We searched PubMed, Clarivate Analytics Web of Science, Google Scholar, and Science Direct databases for appropriate studies. The odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of this association. Also, the effects of four common polymorphisms (rs268, rs285, rs320, and rs328) on the molecular aspects of LPL were evaluated by in silico tools. Five studies were included in meta-analysis after screening.

RESULTS

Our data indicated that rs320 significantly decreased the risk of stroke (G vs. T: OR= 0.64, 95%CI=0.54-0.76; GG vs. TT: OR=0.47, 95%CI=0.29-0.75; TG vs. TT: OR=0.65, 95%CI=0.53-0.80; TG+GG vs. TT: OR=0.62, 95%CI=0.51-0.75; GG vs. TT+TG: OR=0.51, 95%CI=0.32-0.82). Moreover, a significant association between rs285 and diminution of stroke risk was seen (P- vs. P+: OR=0.72, 95%CI=0.58-0.91; P-P- vs. P+P+: OR=0.50, 95%CI=0.31-0.82; P+P-+P-P- vs. P+P+: OR=0.72, 95%CI=0.53-0.96; P-P- vs. P+P++P+P-: OR=0.581, 95%CI=0.369-0.916). Also, the same results were observed after stratifying, without any publication bias (PEgger>0.05). Furthermore, computational analysis revealed that rs268 and rs328 may affect the protein structure (prediction: non-neutral; score=19; expected accuracy=59%) while rs320 could affect the RNA structure (distance=0.2264, P-value=0.0534; P<0.2 is significant).

CONCLUSION

This meta-analysis indicated that risk of stroke was decreased in rs320 and rs285 polymorphisms in the LPL gene.

Cysteinyl Leukotrienes and Their Receptors: Emerging Therapeutic Targets in Central Nervous System Disorders

Cysteinyl leukotrienes are a group of the inflammatory lipid molecules well known as mediators of inflammatory signaling in the allergic diseases. Although they are traditionally known for their role in allergic asthma, allergic rhinitis, and others, recent advances in the field of biomedical research highlighted the role of these inflammatory mediators in a broader range of diseases such as in the inflammation associated with the central nervous system (CNS) disorders, vascular inflammation (atherosclerotic), and in cancer. Among the CNS diseases, they, along with their synthesis precursor enzyme 5-lipoxygenase and their receptors, have been shown to be associated with brain injury, Multiple sclerosis, Alzheimer's disease, Parkinson's disease, brain ischemia, epilepsy, and others. However, a lot more remains elusive as the research in these areas is emerging and only a little has been discovered. Herein, through this review, we first provided a general up-to-date information on the synthesis pathway and the receptors for the molecules. Next, we summarized the current findings on their role in the brain disorders, with an insight given to the future perspectives.

Association of ALOX5AP with ischemic stroke in eastern Chinese

BACKGROUND

5-lipoxygenase protein (ALOX5AP) has been recognized as a susceptibility gene for stroke and coronary artery diseases. The present study was to explore the role of this gene in the eastern Chinese patients with ischemic stroke.

METHODS

Using a case-control design, we studied 658 patients with ischemic stroke and 704 unrelated population-based controls who were age- and sex-matched. The 658 patients were classified by the Trial of Org 10172 in Acute Stroke Treatment (TOAST). Two single-nucleotide polymorphisms (SNPs) covering ALOX5AP were genotyped.

RESULTS

The genotype frequencies of TG of the SNPs rs17222919 located in the promoter of the ALOX5AP gene were significantly higher in patients with ischemic stroke than in controls (OR (*)=1.34, 95%CI(*)=1.02-1.75), especially in patients with ischemic stroke caused by small-artery occlusion (SAO) (OR (*)=1.40, 95%CI(*)=1.02-1.93). Meanwhile, the genotype frequencies of TG and TG/GG were higher in female patients than in the controls. After specification, the genotype frequencies of TG and TG/GG were higher in the patients than in controls with hypertension. The genotype frequencies of AG and AG/GG of the SNPs rs9579646 located in the intron of the ALOX5AP gene were higher in the controls than in the patients. After specification, the genotype frequencies of TG were higher in the controls than patients without hypertension.

CONCLUSION

The present study suggests that sequence variants in the ALOX5AP gene are significantly associated with ischemic stroke.

Arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene rs4073259 polymorphism not associated with ischemic stroke in the northeastern Chinese Han population

OBJECTIVE

Although recent evidence has implicated that 5-lipoxygenase activating protein (ALOX5AP) gene is associated with ischemic stroke (IS) risk, the underlying molecular mechanism remains to be defined. This study aimed to investigate the role of ALOX5AP rs4073259 in ischemic stroke in a Northeastern Chinese Han population.

METHODS

A total of 501 IS patients and 497 healthy controls were enrolled for polymerase chain reaction (PCR) and ligase detection reaction (LDR) analysis of ALOX5AP rs4073259 single nucleotide polymorphism (SNP).

RESULTS

There were no statistically significant differences in ALOX5AP rs4073259 allele and genotype frequencies between IS or subtypes of IS and controls. There was no significant difference in genotype and allele frequencies of atherosclerosis degree between ischemic subjects with carotid artery plaque or absence. However, total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) in women patients were significantly higher than those in men (p=0.015, 0.000, and 0.008, respectively). Total homocysteine (tHcy) was higher in men patients than that in women (p=0.021).

CONCLUSION

There was no statistically significant association of ALOX5AP rs4073259 SNP with ischemic stroke in this northeastern Chinese Han population living in Heilongjiang province, China.

A novel risk haplotype of ALOX5AP gene is associated with ischemic stroke in Chinese Han population

Previous studies have implicated that two at-risk haplotypes (HapA and HapB) of gene-encoding 5-lipoxygenase-activating protein (ALOX5AP) were significantly associated with stroke. The aim of this study was to explore the association between haplotypes of ALOX5AP gene and risk for ischemic stroke (IS) in Chinese Han population. A total of 492 patients with IS and 490 matched control subjects were recruited. Six ALOX5AP SNPs (SG13S377, SG13S114, SG13S41, SG13S89, SG13S32 and SG13S35) were genotyped by SNaPshot minisequence technique. A common genetic variant SG13S114/AA in the ALOX5AP gene was associated with IS in this Chinese cohort (OR = 2.514, 95 % CI = 1.667 ~ 3.790). HapA (TGA) and HapB (AAAG) had no significant difference in the patients (36.3 and 18.5 %, respectively) and controls (37.6 and 16.3 %, respectively) (P = 0.631 and P = 0.375, respectively). But, the frequency of Hap (GAAG) was significantly higher in the patients than that in the controls after Bonferroni's adjustment (P = 0.006). To conclude, SG13S114/AA of the ALOX5AP gene was associated with an increased risk for IS. A novel risk haplotype, Hap (GAAG) was a genetic risk factor for IS in this Chinese population.

Variants of the arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene and risk of ischemic stroke in Han Chinese of eastern China

Variants of the arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene have been suggested to play an important role in the pathogenesis of atherosclerosis and ischemic stroke. This study was aimed to explore the association of ALOX5AP variants with ischemic stroke risk in Han Chinese of eastern China. A total of 690 ischemic stroke cases and 767 controls were recruited. The subjects were further subtyped according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria. On the basis of that, two polymorphisms of the ALOX5AP gene (rs10507391 and rs12429692) were determined by TaqMan genotyping assay. In addition, plasma leukotriene B4 (LTB4) levels were analyzed in these subjects. There was no evidence of association between the two variants of ALOX5AP and the risk of ischemic stroke or its TOAST-subtypes. Haplotype analysis and stratification analysis according to sex, age, body mass index, hypertension, and diabetes also showed negative association. Analysis of LTB4 levels in a subset of cases and controls revealed that LTB4 levels were significantly higher in ischemic stroke cases than in the controls (70.06±14.75 ng/L vs 57.34±10.93 ng/L; P = 0.000) and carriers of the T allele of the rs10507391 variant were associated with higher plasma LTB4 levels (P = 0.000). The present study suggests there is no association of the two polymorphisms in the ALOX5AP gene with ischemic stroke risk in Han Chinese of eastern China.

Correlation between cerebral infarction and ALOX5AP gene expression

Linkage/linkage-disequilibrium analysis studies, based on positional information and gene function, indicated that ALOX5AP gene was an independent risk factor of cerebral infarction in humans; however, this needs to be verified among different populations. Herein, we verified whether ALOX5AP was a risk factor of cerebral infarction in the Chinese Han population. For this purpose, 547 cerebral infarction patients were enrolled as the case group; the control group comprised 794 healthy, age-matched individuals unrelated to case group and had no history of cerebral infarction/transient ischemic attack. Regarding single-nucleotide polymorphism (SNP) selection and ALOX5AP genotyping, we selected four SNP loci (SG13S25, SG13S114, SG13S89, and SG13S32) and determined allelic frequencies. Genotyping of SG13S114 and SG13S32 adopted a method of combining real-time quantitative PCR and allele-specific PCR. A linkage-disequilibrium analysis of ALOX5AP was also performed. We found that the allelic frequencies of SG13S25 and SG13S89 were below 5% and those of SG13S114 and SG13S32 were above 5%. We did not find any differences between the case and control groups regarding allele, allele types, and haplotype gene frequencies of two SNP loci. The results indicate that the two genetic polymorphisms of ALOX5AP, SG13S114 and SG13S32, are not associated with cerebral infarction in Chinese Han population.

Genetic variation in members of the leukotrienes biosynthesis pathway confers risk of ischemic stroke in Eastern Han Chinese

This study was aimed to explore the association of genetic variation in members of the leukotrienes biosynthesis pathway as potential mediators with ischemic stroke (IS) risk in Eastern Han Chinese. A case-control study of was conducted with five selected single nucleotide polymorphisms (SNPs). In the single-locus analysis, carriers of C allele of rs730012 in LTC4S were more susceptible to IS (OR, 1.28; 95% CI, 1.02-1.60; P=0.033). Under the recessive genetic model, ALOX5 rs2029253 variant reduced IS risk (adjusted OR, 0.78; 95% CI, 0.60-1.00; P=0.048) while LTA4H rs6538697 and LTC4S rs730012 variants increased (adjusted OR, 1.66; 95% CI, 1.04-2.64; P=0.032 and adjusted OR, 3.63; 95% CI, 1.01-13.05; P=0.048, respectively). However, there was no evidence of association between all five SNPs and IS risk after correction for multiple testing. In combined analysis of multiple genes and loci, individuals with ALOX5AP rs12429692 T allele, ALOX5 rs2029253 A allele, and LTA4H rs6538697 C allele suggested a significantly increased susceptibility to IS (adjusted OR, 1.70; 95% CI, 1.07-2.69; P=0.024). The present study suggested gene-gene interactions in leukotrienes pathway could exert influences on the risk of IS.

Association between arachidonate 5-lipoxygenase-activating protein (ALOX5AP) and lung function in a Korean population

Arachidonate 5-lipoxygenase-activating protein (ALOX5AP) plays a role in the 5-lipoxygenase (LO) pathway, which includes the LTC(4), LTD(4), LTE(4) and LTB(4). These leukotrienes are known causative factors of asthma, allergy, atopy and cardiovascular diseases. ALOX5AP lacks enzyme activity and acts by helping 5-LO function. In this study, healthy and general subjects who live in rural and urban areas of Korea were tested for the association of ALOX5AP polymorphisms with lung function. Lung function was also estimated by calculating the predicted values for forced expiratory volume in one second (FEV(1) _%PRED) and the proportion of the forced vital capacity exhaled in the first second (FEV(1) /FVC_PRED). The linear regression was adjusted for residence area, gender, age, height and smoking status. The analysis revealed associations between FEV(1) and the single-nucleotide polymorphism (SNP) rs9506352 and the haplotype TCAC (permuted P-value < 0.05). The linkage disequilibrium block that included the significant SNPs overlapped with SNPs that were revealed previously to associate with myocardial infarction and asthma and to affect lung function. This study is the first to demonstrate the association between lung function and ALOX5AP polymorphisms in a healthy and general population.

The role of PRKCH gene variants in coronary artery disease in a Chinese population

The aim of the present study was to assess the influences of PRKCH gene variants (1425G/A and _15) on the risk of coronary artery disease (CAD) in a Chinese population. Our study population consisted of 470 CAD patients and 434 control subjects. The alleles frequencies of the two variants were significantly higher among CAD patients than control subjects (P = 0.001 for 1425G/A and P = 0.001 for _15, respectively). In the CAD group, the A allele carriers of 1425G/A and _15 polymorphisms had higher low-density lipoprotein cholesterol (LDL-C) levels than homozygote G allele carriers (P = 0.001 and P = 0.021, respectively). In a multiple logistic regression model adjusted for age, sex, body mass index (BMI), etc., a markedly increased risk of developing CAD was found in subjects carrying GA or AA genotype (P = 0.005 and P = 0.018, respectively). In conclusion, we observed that there was a remarkable association of minor alleles (1425G/A and _15) in the PRKCH gene with an elevated risk of CAD and increased levels of LDL-C in this Chinese population.