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

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 clinical and environmental determinants of airway transcriptional profiles in allergic asthma

RATIONALE

Gene expression profiling of airway epithelial and inflammatory cells can be used to identify genes involved in environmental asthma.

METHODS

Airway epithelia and inflammatory cells were obtained via bronchial brush and bronchoalveolar lavage (BAL) from 39 subjects comprising three phenotypic groups (nonatopic nonasthmatic, atopic nonasthmatic, and atopic asthmatic) 4 hours after instillation of LPS, house dust mite antigen, and saline in three distinct subsegmental bronchi. RNA transcript levels were assessed using whole genome microarrays.

MEASUREMENTS AND MAIN RESULTS

Baseline (saline exposure) differences in gene expression were related to airflow obstruction in epithelial cells (C3, ALOX5AP, CCL18, and others), and to serum IgE (innate immune genes and focal adhesion pathway) and allergic-asthmatic phenotype (complement genes, histone deacetylases, and GATA1 transcription factor) in inflammatory cells. LPS stimulation resulted in pronounced transcriptional response across all subjects in both airway epithelia and BAL cells, with strong association to nuclear factor-κB and IFN-inducible genes as well as signatures of other transcription factors (NRF2, C/EBP, and E2F1) and histone proteins. No distinct transcriptional profile to LPS was observed in the asthma and atopy phenotype. Finally, although no consistent expression changes were observed across all subjects in response to house dust mite antigen stimulation, we observed subtle differences in gene expression (e.g., GATA1 and GATA2) in BAL cells related to the asthma and atopy phenotype.

CONCLUSIONS

Our results indicate that among individuals with allergic asthma, transcriptional changes in airway epithelia and inflammatory cells are influenced by phenotype as well as environmental exposures.

Phosphodiesterase 4D and 5-lipoxygenase activating protein genes and risk of ischemic stroke in Sardinians

Genetic factors contribute to the risk of ischemic stroke (IS). The phosphodiesterase-4D (PDE4D) and the 5-lipoxygenase activating protein (ALOX5AP) genes were identified as contributors to stroke in an Icelandic population. In an attempt to better define the contributory role of PDE4D and ALOX5AP genes to the risk of IS in humans, we carried out the present association study in a well-characterized, earlier published, genetically homogenous population from the island of Sardinia, Italy. In this cohort, including 294 cases and 235 controls, age, hypertension, hypercholesterolemia, and atrial fibrillation represent risk factors for IS. The PDE4D gene was evaluated by four single nucleotide polymorphisms (SNP32, SNP45, SNP83, SNP87) and by the microsatellite AC008818-1; the ALOX5AP gene was characterized by three SNPs (SG13S32, SG13S89, ALO2A). The results of our study provide no evidence of association between any single PDE4D and ALOX5AP gene variant with the risk of IS in the Sardinian cohort. Haplotype analysis, including that constructed with allele 0 of microsatellite AC008818-1 and SNP45 of the PDE4D gene, was also negative. In conclusion, we found no evidence of association between PDE4D and ALOX5AP genes and the risk of IS in a genetically homogenous population from Sardinia.

Pharmacogenetics of asthma

Asthma is a common disease characterized by airway inflammation and bronchorestriction. There are several common categories of medications for treating asthma; however, not all asthmatics have the same response to these medications, some of which are adverse responses that are potentially life threatening. Because interindividual responses to asthma medications can vary considerably, the potential for genetic contributions to variable drug responses is significant. This chapter reviews the most common biological pathways targeted by asthma therapy and briefly discusses the genetic contribution to varied responses to asthma therapy for four common types of asthma medications: beta-agonists, anticholinergics, leukotriene modifiers, and corticosteroids.

Plasma C-reactive protein and 5-lipoxygenase-activating protein gene promoter poly-A polymorphism in patients with coronary artery disease

OBJECTIVES

The purpose of this study was to explore the possible associations of the 5-lipoxygenase-activating protein (FLAP) poly-A genotype, plasma high-sensitivity C-reactive protein (hsCRP) and the extent score of coronary artery disease (CAD).

METHODS

The 17A/21A genotypes and plasma hsCRP levels were determined in 555 Chinese patients, 424 with and 131 without CAD. The luciferase reporter assay was performed to explore the functional significance of promoter poly-A polymorphism.

RESULTS

CAD patients showed significantly higher plasma hsCRP (p = 0.007) than non-CAD subjects, but no differences in the 17A allele carriers and frequency. The extent score of CAD was significantly correlated with plasma hsCRP (p = 0.03). Furthermore, the 17A allele carriers showed significantly higher hsCRP than the 21A homozygotes (p = 0.02). Multiple linear regression analysis documented an impact of the poly-A genotype on plasma hsCRP (p = 0.03). In vitro, the 17A construct was found to have greater promoter activity than the 21A construct (p = 0.02).

CONCLUSIONS

The present study demonstrated a significant correlation of FLAP gene promoter 17A allele carriers with higher plasma hsCRP levels in patients with CAD. This association might be related to the increased transcriptional activity of the FLAP gene and the resulting pro-inflammatory effect on the 5-lipoxygenase pathway.