Polymorphisms in the 5-lipoxygenase activating protein (ALOX5AP) gene are not associated with asthma in an Australian population

BACKGROUND: The cysteinyl-leukotrienes (cys-LTs) are important pro-inflammatory mediators in asthma, and have been shown to have a role in specific disease subtypes, including asthma severity. Few studies have investigated the role of polymorphisms in the ALOX5AP gene, encoding 5-lipoxygenase activating protein (FLAP), and asthma. We hypothesized that polymorphisms in this gene are associated with asthma and in particular, with asthma severity, in an Australian population. OBJECTIVE: To screen the coding region of the ALOX5AP gene for polymorphisms and to determine the association between previously described polymorphisms and asthma and asthma severity in an Australian population. METHODS: We used PCR-SSCP and PCR-RFLP analysis to examine a previously described promoter polyA variable repeat polymorphism and two intronic polymorphisms (IVS2+12C>A, IVS2+105T>C), and to screen all five exons of the gene for new polymorphisms, in a large Australian population of randomly selected, non-asthmatic controls (n=457), mild asthmatics (n=274), moderate asthmatics (n=231) and severe asthmatics (n=79). RESULTS: We confirmed the presence of two polymorphisms in intron 2 and found no association between these polymorphisms and asthma or asthma severity, nor between a promoter polymorphism in the ALOX5AP gene and asthma or asthma severity. Gene fragment analysis of the promoter polymorphism revealed novel, conserved repeat numbers in our population, and no new polymorphisms were found in the coding region of the gene. CONCLUSION: These findings in a large, well characterized asthma population, reveal that, while FLAP is an important enzyme in cys-LTs biosynthesis, polymorphisms in the ALOX5AP gene are not likely to be functionally associated with the asthma phenotype.     

The role of LTA4H and ALOX5AP polymorphism in asthma and allergy susceptibility

Background: Leukotrienes (LTs) have been identified as central mediators in asthma and allergy. Pharmacological inhibition of cysteinyl‐LT activity improves asthma symptoms and control. Accumulating evidence suggests a role for the dihydroxy leukotriene LTB₄ in airway disease. LTA₄ hydrolase and 5‐lipoxygenase activating protein have key roles in LTB₄ production. Single nucleotide polymorphism (SNPs) and haplotypes spanning the LTA4H and ALOX5AP genes have been associated with LTB₄ production and myocardial infarction (MI). Objective: To assess the contribution of LTA4H and ALOX5AP polymorphism to asthma and allergy susceptibility. Methods: Three hundred and forty‐one Caucasian families (two asthmatic siblings) were genotyped for eight SNPs spanning ALOX5AP and five SNPs spanning LTA4H. Association analyses of asthma and related phenotypes (total IgE, atopy, bronchial hyper‐responsiveness, FEV₁) were undertaken using the Family Based Association Test. Results: Single point analyses identified association (P < 0.05) between SNPs SG13S114, SG13S89, SG13S41 (ALOX5AP), rs1978331 (LTA4H) and asthma and/or related phenotypes. Haplotype analyses using all LTA4H SNPs identified a single key risk haplotype for the development of asthma (P = 0.006) and related phenotypes (P = 0.042–0.005). Haplotype analyses using all ALOX5AP SNPs identified several asthma and atopy risk and protective haplotypes. There was limited correlation with previously identified MI risk haplotypes in both genes. Carriers of both ALOX5AP SG13S41 and LTA4H rs1978331 alleles had an increased risk of developing asthma (OR 2.17, CI 1.41–3.32). Conclusions: These data provide evidence for the role of SNPs spanning the ALOX5AP and LTA4H genes in asthma and atopy susceptibility in the Caucasian population and support a role for LTB₄ in disease pathogenesis.     

No association of ALOX5AP polymorphisms with risk of MRI-defined brain infarcts

The arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene has been associated with stroke. The majority of the reported ALOX5AP associations have considered non-radiologically confirmed infarcts as the stroke phenotype. We assessed the association of genetic variants in ALOX5AP with stroke defined by the presence of infarcts on brain magnetic resonance imaging (MRI). We studied 202 persons with MRI-defined brain infarcts and 487 healthy individuals of Caribbean Hispanic ancestry. Another sample of European ancestry comprised 1823 persons with MRI-defined brain infarct and 7578 control subjects. Subjects were genotyped for the 4 single nucleotide polymorphisms (SNPs) that define ALOX5AP HapA haplotype. No association was found between SNPs and MRI-defined brain infarcts. Our data do not support the hypothesis that variants in ALOX5AP are associated with risk of MRI-defined brain infarcts.     

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 LTA4H and ALOX5AP genes in the risk for asthma in Latinos

Background Leukotrienes play an important role in allergic and inflammatory diseases, but reports on the involvement of arachidonate 5‐lipoxygenase‐activating protein (ALOX5AP) and leukotriene A₄ hydrolase (LTA4H) in asthma have been inconclusive. Objective To determine whether polymorphisms in ALOX5AP and LTA4H genes are risk factors for asthma in two different Latino groups: Mexicans and Puerto Ricans. Methods The LTA4H gene was sequenced in individuals from both groups to identify novel polymorphisms. Single‐nucleotide polymorphisms (SNPs) in the ALOX5AP and LTA4H genes were analysed for associations with asthma and asthma‐related phenotypes in 687 parent–child trios of Mexican and Puerto Rican origin. Results In LTA4H, five previously unknown polymorphisms were identified. Two SNPs within LTA4H (rs17525488 and rs2540493) were protective for asthma in Latinos (P=0.007 and 0.05, respectively). Among the Mexican patients, LTA4H polymorphisms were associated with baseline lung function and IgE levels. For ALOX5AP, the minor allele at SNP rs10507391 was associated with protection from asthma (odds ratio=0.78, P=0.02) and baseline lung function (P=0.018) in Puerto Ricans. A gene–gene interaction was identified between LTA4H (rs17525488) and ALOX5AP (rs10507391), (P=0.003, in the combined sample). Conclusion Our results support the role of LTA4H and ALOX5AP variants as risk factors for asthma in Latino populations. Cite this as: M. Via, A. De Giacomo, H. Corvol, C. Eng, M. A. Seibold, C. Gillett, J. Galanter, S. Sen, H. Tcheurekdjian, R. Chapela, J. R. Rodríguez‐Santana, W. Rodríguez‐Cintrón, S. Thyne, P. C. Avila, S. Choudhry and E. González Burchard on behalf of the Genetics of Asthma in Latino Americans (GALA) Study, Clinical & Experimental Allergy, 2010 (40) 582–589.     

ALOX5AP基因SG13S114A/T多态性与颈动脉粥样硬化斑块稳定性的相关性

目的 探讨花生四烯酸5-脂氧合酶激活蛋白(arachidonate 5-lipoxygenase acttvating protein,ALOX5AP)基因SG13S114 A/T的多态性与颈动脉粥样硬化斑块稳定程度的关系.方法 应用聚合酶链反应-限制性片段长度多态性分析法检测132例颈动脉易损斑块及152例稳定斑块的急性脑梗死者ALOX5AP基因SG13S114 A/T基因型,比较两组间该位点多态性的差异.结果 易损斑块组ALOX5AP基因SG13S114 AA基因型和A等位基因频率高于稳定斑块组,两组差异有统计学意义(P＜0.01),其中男性和女性上述基因型和等位基因频率的比较,易损斑块组均高于稳定斑块组,两组差异有统计学意义(P＜0.01).结论 ALOX5AP基因SG13S114 A/T多态性可能与动脉粥样斑块的稳定性有关,其中SG13S114 A等位基因可能是易损斑块的风险因素.     

5-羟色胺转运体基因多态性与支气管哮喘及抑郁症易感性的研究

目的 检测5-羟色胺转运体(5-hydroxytryptamine transporter,5-HTT)基因的两种多态性(5-HTTLPR及Stin2),以探讨哮喘合并抑郁症的分子遗传学机制.方法 收集成人哮喘患者156例,采用汉密尔顿抑郁量表(Hamilton depression scale,HAMD)进行抑郁评分,将哮喘组分为哮喘合并抑郁组(HAMD≥8分)和单纯哮喘组(HAMD<8分).另设立两组对照,即抑郁症组(n=508)和健康对照组(n=433).采集所有受试者外周血,应用聚合酶链反应方法,扩增包括5-HTTLPR或Stin2多态区域的5-HTT基因片段,在琼脂糖凝胶电泳后使用全自动凝胶数码成像及分析系统分析扩增目的 基因片段.结果 Stin2多态性的基因型频率分布和等位基因频率分布显示,具有Stin2.12/Stin2.10基因型或Stin2.10等位基因型的男性发生哮喘的风险明显增加(Stin2.12/Stin2.10:OR=2.291,95%CI:1.195,4.390;Stin2.10:OR=1.942,95%CI:1.069-3.527),而5-HTTLPR的基因型和等位基因频率分布在哮喘(包括哮喘合并抑郁组和单纯哮喘组)或按性别分层的哮喘与健康对照之间的差异均无统计学意义(P均>0.05).结论 5-HTT基因Stin2多态位点可能在男性哮喘发病中发挥一定作用,该结果支持哮喘与抑郁之间可能存在一定遗传学发病机制相关性的假设.     

Polymorphisms in the interleukin-4 and interleukin-4 receptor α chain genes confer susceptibility to asthma and atopy in a Caucasian population

BACKGROUND : IL-4 by binding to its receptor (IL-4R) is essential for the development of airway inflammation present in asthma, through the induction of IgE synthesis in B cells and differentiation of T cells to a Th2 phenotype. OBJECTIVE : To investigate the role of four common polymorphisms in the IL-4 (IL4-34CT and IL4-589CT) and IL-4Ralpha chain (IL4RAI50V and IL4RAQ576R) genes in conferring susceptibility to the development of atopy and/or asthma. METHODS : Two polymorphisms in the IL-4 gene promoter, IL4-34CT and IL4-589CT, and two polymorphisms in the IL-4Ralpha chain gene, IL4RAI50V and IL4RAQ576R, have been genotyped using PCR-based methods in 341 asthmatic families and in 184 non-asthmatic adults recruited from the south of England. RESULTS : Case-control analysis did not reveal differences in the distribution of the four polymorphisms between asthmatics and controls. However, the transmission disequilibrium test showed that the IL4-589 T allele was preferentially transmitted to asthmatic children (P=0.036) and that the IL4RAQ576 was preferentially transmitted to children with atopic asthma (P=0.018). Haplotype analysis showed a strong association between the IL4-34T/-589T haplotype and asthma per se (P=0.041), and a strong association between the IL4RA I50/Q576 haplotype and atopic asthma (P=0.006). CONCLUSION : Our data suggest that polymorphisms in the IL-4 and IL-4Ralpha chain genes might play a role both conferring susceptibility to and modulating severity of atopy and asthma.     

Association of interleukin genes polymorphism with asthma susceptibility in Indian children: a case-control study

Background: Interleukins (IL) 4 and 13 genes and their receptors (R) are the key cytokines which amplify inflammatory reactions in asthma.

Objective: This study aimed to investigate the association of IL 4, 4?R, 13 and 13?R genes polymorphism with asthma in Indian children.

Methods: In this hospital-based case-control study, included were children aged 1–15 years recruited as diagnosed cases of bronchial asthma, according to EPR 2007 and excluded were subjects with other respiratory diseases. Children with no present or past history of asthma were enrolled as controls. Spirometry was done in cases age ≥ 6 years. Gene–gene interaction was evaluated using binary logistic regression.

Results: From October 2010 to July 2013, 275 cases and 275 controls were recruited. Gene–gene interactions between C1112T in IL 13 and Ile50Val in IL 4?R gene polymorphisms were found to be statistically significant (OR?=?2.37, 95% CI?=?1.04–5.42, p?=?0.040). Individuals with CT and GG genotype of C1112T in IL 13 and Ile50Val in IL 4?R were at twice the risk for the development of asthma compared to individuals with both non-risk genotypes.

Conclusion: The data suggests that gene–gene interactions between IL 13 and IL 4?R genes may play an important role in asthma among Indian children.     

5-Lipoxygenase (ALOX5) and FLAP (ALOX5AP) gene polymorphisms as factors in vascular pathology and Alzheimer's disease

We first hypothesized in 2000 that a polymorphism of the human gene encoding the enzyme 5-lipoxygenase (5-LOX) might be associated with Alzheimer's disease. Only a little progress has been made in directly testing our proposal. However, additional important new data lead us to hypothesize that genetic variability not only in the 5-LOX gene, i.e., ALOX5, but also in polymorphism of the five-lipoxygenase activating protein (FLAP) gene, i.e., ALOX5AP, may be associated with Alzheimer's pathology. Studies in mice followed by several extensive clinical studies have identified ALOX5 and ALOX5AP polymorphisms as strong risk factors for atherosclerosis and cerebrovascular pathologies. New data point to a significant aggregation of vascular risk factors and risk of Alzheimer's disease. Preliminary findings in postmortem brain of Alzheimer's patients identified elevated 5-LOX immunostaining in this disease. We suggest that our hypothesis of a link between the ALOX5 and ALOX5AP gene polymorphisms and Alzheimer's disease could be tested in a clinical setting and in animal models, i.e., transgenic mice could be produced by crossing the available 5-LOX-deficient mice with the available transgenic mice models of Alzheimer's disease.     

Association between polymorphisms in serine protease inhibitor, kazal type 5 and asthma phenotypes in a large German population sample

BACKGROUND: Atopic diseases are characterized by immunoglobulin E (IgE)-mediated immune responses towards common allergens, many of which are proteases. Recently it has been suggested that a proteinase inhibitor gene, SPINK5, which is located on chromosome 5q31, may play a role in the pathogenesis of atopic diseases. OBJECTIVE: We investigated the association between the polymorphism G1258A leading to a putative amino acid change (Glu420Lys) in serine protease inhibitor, kazal type 5 (SPINK5) and phenotypes of atopic diseases in a large general population sample of German children. METHODS: Parental questionnaires were used and children underwent skin prick testing, pulmonary function testing and bronchial challenge. Blood was collected for serum IgE measurements and DNA extraction. In total, 1161 children were genotyped for the SPINK5 Glu420Lys polymorphism and association studies were performed. RESULTS: A significant association between SPINK5 420Lys and the development of asthma was observed (OR 1.77; 95%CI: 1.02-3.06, P=0.041 for 420Lys homocygotes). Atopic carriers of SPINK5 420Lys showed an increased risk for asthma and asthma symptoms (OR 2.06; 95%CI: 1.01-4.20, P=0.047). When children with a combination of asthma and atopic dermatitis were compared with normal controls, the SPINK5 420Lys genotype was more prevalent in the disease group (OR 4.56; 95%CI: 1.370-15.12, P=0.007). No association between SPINK5 420Lys genotypes and total serum IgE levels, skin prick test (SPT) reactivity or atopic dermatitis was observed. CONCLUSION: These results suggest that SPINK5 Glu420Lys polymorphism may be associated with certain asthma phenotypes characterized by the concomitant expression of asthma and atopic dermatitis or SPT reactivity.     

Effects of MK-886, a 5-lipoxygenase activating protein (FLAP) inhibitor, and 5-lipoxygenase deficiency on the forced swimming behavior of mice

A common biological pathway may contribute to the comorbidity of atherosclerosis and depression. Increased activity of the enzymatic 5-lipoxygenase (5-LOX, 5LO) pathway is a contributing factor in atherosclerosis and a 5-LOX inhibitor, MK-886, is beneficial in animal models of atherosclerosis. In the brain, MK-886 increases phosphorylation of the glutamate receptor subunit GluR1, and the increased phosphorylation of this receptor has been associated with antidepressant treatment. In this work, we evaluated the behavioral effects of MK-886 in an automated assay of mouse forced swimming, which identifies antidepressant activity as increased climbing behavior and/or decreased rest time. Whereas a single injection of MK-886 (3 and 10 mg/kg) did not affect forced swimming behaviors assayed 30 min later, six daily injections of 3 mg/kg MK-886 slightly increased climbing and significantly reduced rest time in wild-type mice but not in 5-LOX-deficient mice. A diet delivery of MK-886, 4 micro/(100 mg(body-weight)day), required 3 weeks to affect forced swimming; it increased climbing behavior. Climbing behavior was also increased in naive 5-LOX-deficient mice compared to naive wild-type controls. These results suggest that 5-LOX inhibition and deficiency may be associated with antidepressant activity. Increased climbing in a forced swimming assay is a typical outcome of antidepressants that increase noradrenergic and dopaminergic activity. Interestingly, 5-LOX deficiency and MK-886 treatment have been shown to be capable of increasing the behavioral effects of a noradrenaline/dopamine-potentiating drug, cocaine. Future research is needed to evaluate the clinical relevance of our findings.     

Lack of association of HLA class I genes and TNF alpha-308 polymorphism in toluene diisocyanate-induced asthma

BACKGROUND: Toluene diisocyanate (TDI)-induced asthma is a common cause of occupational asthma and it affects 5-15% of the exposed population suggesting an underlying genetic susceptibility. METHODS: To investigate the role of genetic factors in the development of TDI-induced asthma, we analyzed the distribution of human leukocyte antigen (HLA) class I genes and of tumor necrosis factor (TNF)-alpha A-308G polymorphism in 142 patients with TDI-induced asthma and in 50 asymptomatic exposed subjects. RESULTS: Neither the distribution of HLA class I antigens nor the distribution of TNF-alpha A-308G polymorphism was different between patients with TDI-induced asthma and asymptomatic exposed subjects. CONCLUSIONS: These results suggest that HLA class I antigens and TNF-alpha A-308G are not associated with susceptibility or resistance to the development of TDI-induced asthma.     

TIM-4基因多态性与湖北地区汉族人群支气管哮喘易感性的研究

目的 探讨T细胞免疫球蛋白域及黏蛋白域蛋白-4(T cells immunoglobulindomain andmucindomain protein-4,TIM-4)基因外显子2区Lys65Lys(G/A)、外显子9区Val1365Met(G/A)的单核昔酸多态性(SNP)与湖北地区汉族人群支气管哮喘易感性的关系.方法 采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)的方法对湖北地区185例哮喘患者和162例健康者TIM-4基因外显子2区Lys65Lys(G/A)、外显子9区Vai365Met(G/A)的多态性进行分析,计算基因型和等位基因频率.结果 (1)湖北地区汉族人群健康者TIM-4基因外显子2区Lys65Lys(G/A)位G/G、G/A、A/A基因型频率分别为0.840、0.160、0,而哮喘人群其频率分别为0.859、0.141、0,其基因型和等位基因型频率与对照组相比差异均无统计学意义(P=0.603,P=0.618);(2)本试验未检测到TIM-4外显子9区Va1365Met(G/A)的多态性.结论 湖北地区汉族人群TIM-4基因外显子2区Lys65Lys(G/A)存在单核苷酸多态性变异,但该位点的变异与湖北地区汉族人群支气管哮喘易感性无关;TIM-4基因外显子9区Va1365Met(G/A)在湖北地区汉族人群中未发现单核苷酸多态性.