Association of ATP8B3 gene polymorphisms with aspirin-exacerbated respiratory disease in asthmatics.

BACKGROUND: Aspirin-exacerbated respiratory disease (AERD), an asthma phenotype, often presents with severe manifestations and it remains widely underdiagnosed because of insufficient awareness of the relationship between the ingestion of nonsteroidal anti-inflammatory drugs, including acetylsalicylic acid (ASA), and asthma exacerbation. Our previous genome-wide association study demonstrated an association between a single nucleotide polymorphism (SNP) of the ATP8B3 gene and the risk of AERD. This study examined AERD-related SNPs of the ATP8B3 gene in a large population. METHODS: Twenty-five SNPs of ATP8B3 were genotyped with the GoldenGate assay using VeraCode microbeads in 141 asthmatics with AERD and 995 Aspirin-tolerant asthma (ATA). The genotype distribution was analyzed using logistic regression models. The declines in forced expiratory volume in 1 second (FEV1)following an ASA challenge were compared among the genotypes and haplotypes using a type III generalized linear model. RESULTS: The minor allele frequencies (MAFs) of rs10421558 A>G in the 5'UTR and rs10403288 G>A in the intron were significantly lower in the AERD than the ATA [34.0% vs. 43.8%, OR = 0.66 (0.62-0.92), Pcorr = 0.03 and 28.4% vs. 35.4%, OR = 0.62 (0.59-0.89), Pcorr = 0.016, respectively]. BL1ht5 was significantly higher in the AERD [7.6% vs. 1.6%, OR = 12.23 (0.2-0.51), P = 4.7 × 10 -4 , Pcorr = 0.001]. Among them, rs10421558 A>G and BL1ht5 were associated with the percent decline in FEV1 on the oral ASA challenge test. CONCLUSION: The minor allele of rs10421558 A>G in the 5'UTR may protect against the development of AERD via the increased production of ATP8B3.

Epigenetic Changes in Asthma: Role of DNA CpG Methylation.

For the past three decades, more than a thousand of genetic studies have been performed to find out the genetic variants responsible for the risk of asthma. Until now, all of the discovered single nucleotide polymorphisms have explained genetic effects less than initially expected. Thus, clarification of environmental factors has been brought up to overcome the 'missing' heritability. The most exciting solution is epigenesis because it intervenes at the junction between the genome and the environment. Epigenesis is an alteration of genetic expression without changes of DNA sequence caused by environmental factors such as nutrients, allergens, cigarette smoke, air pollutants, use of drugs and infectious agents during pre- and post-natal periods and even in adulthood. Three major forms of epigenesis are composed of DNA methylation, histone modifications, and specific microRNA. Recently, several studies have been published on epigenesis in asthma and allergy as a powerful tool for research of genetic heritability in asthma albeit epigenetic changes are at the starting point to obtain the data on specific phenotypes of asthma. In this presentation, we mainly review the potential role of DNA CpG methylation in the risk of asthma and its sub-phenotypes including nonsteroidal anti-inflammatory exacerbated respiratory diseases.

Prevalence of Respiratory Viral Infections in Korean Adult Asthmatics With Acute Exacerbations: Comparison With Those With Stable State.

PURPOSE: Viral infections are involved in ~50% of exacerbations among Caucasian adult asthmatics. However, there have been few reports on the causative virus of exacerbations in Korean adult asthmatics. Thus, we compared frequencies and types of viruses between lower respiratory tract illnesses (LRTIs) with exacerbations (exacerbated LRTIs) and those without exacerbations (stable LRTIs) to evaluate contribution of respiratory viruses to exacerbations. METHODS: Viral RNA was extracted from sputum using the Viral Gene-spin™ Kit. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to detect adenovirus (ADV), metapneumovirus (MPV), parainfluenza virus (PIV) 1/2/3, influenza virus (IFV) A, IFV B, respiratory syncytial virus (RSV) A/B, and rhinovirus (RV) A. RESULTS: Among the 259 patients, 210 underwent a single sputum examination, and the remaining 49 underwent 2 to 4 sputum examinations. Virus was detected in 68 of the 259 exacerbated episodes and in 11 of the 64 stable episodes. Among the exacerbated episodes, RV was the most frequently detected virus, followed by influenza A, parainfluenza, RSV A/B, and ADV. Among the 11 stable episodes, RV was most frequently detected. Detection rates of these viruses did not differ between the 2 groups (P>0.05). Thirty-five patients underwent the virus examination at 2 episodes of exacerbation, while 14 patients underwent at each time of exacerbated and stable episodes. Virus detection rate at the second examination was significantly higher in cases with 2 exacerbation episodes than in those with initial exacerbation and sequential stable episodes (P=0.003). A seasonal pattern was noted in the detection rates of RV (September to December), IFV (January to April), PIV (May to September), and RSV A/B (September to April). CONCLUSIONS: Respiratory viruses were identified in approximately 20% of LRTI irrespective of the presence of asthma exacerbation. RV and IFV A/B were most frequently detected. A group of patients experienced frequent viral infections followed by asthma exacerbations.

Upregulation of interleukin-33 and thymic stromal lymphopoietin levels in the lungs of idiopathic pulmonary fibrosis.

BACKGROUND: Innate T helper type 2 (Th2) immune responses mediated by interleukin (IL)-33, thymic stromal lymphopoietin (TSLP), and IL-25 have been shown to play an important role in pulmonary fibrosis of animal models; however, their clinical implications remain poorly understood. METHODS: TSLP, IL-25, and IL-33 concentrations were measured in bronchoalveolar lavage fluids obtained from normal controls (NCs; n = 40) and from patients with idiopathic pulmonary fibrosis (IPF; n = 100), non-specific interstitial pneumonia (NSIP; n = 22), hypersensitivity pneumonitis (HP; n = 20), and sarcoidosis (n = 19). RESULTS: The TSLP and IL-33 levels were significantly higher in patients with IPF relative to the NCs (p = 0.01 and p = 0.0001, respectively), NSIP (p = 4.95E - 7 and p = 0.0002, respectively), HP (p = 0.00003 and p = 0.000005, respectively), and sarcoidosis groups (p = 0.003 and p = 0.0001, respectively). However, the IL-25 levels were not significantly different between NC and IPF group (p = 0.432). Receiver operating characteristic curves of the TSLP and IL-33 levels revealed clear differences between the IPF and NC groups (AUC = 0.655 and 0.706, respectively), as well as between the IPF and the other lung disease groups (AUC = 0.786 and 0.781, respectively). Cut-off values of 3.52 pg/µg TSLP and 3.77 pg/µg IL-33 were shown to differentiate between the IPF and NC groups with 99.2 and 94.3% accuracy. Cut-off values of 4.66 pg/µg TSLP and 2.52 pg/µg IL-33 possessed 99.4 and 93.2% accuracy for differentiating among the IPF and other interstitial lung disease groups. CONCLUSIONS: Innate immune responses may be associated with the development of IPF. Furthermore, the IL-33 and TSLP levels in BAL fluids may be useful for differentiating IPF from other chronic interstitial lung diseases.

Association of interleukin-25 levels with development of aspirin induced respiratory diseases.

BACKGROUND: Aspirin-exacerbated respiratory diseases (AERD) are caused by ingestion of non-steroidal anti-inflammatory drugs and are characterized by acute bronchospasms and marked infiltration of eosinophils, the latter being attributable to altered synthesis of cysteinyl leukotrienes (LT) and prostaglandins (PG). Recently, the innate Th2 response is revealed to induce eosinophil infiltration in allergic inflammation, however the role of the innate Th2 response has not been studies in AERD. Thus, we evaluated the relationship between the innate Th2 cytokines including IL-25, thymic stromal lymphopoietin (TSLP) and IL-33 and the development of AERD. METHODS AND MATERIALS: Plasma IL-25, IL-33, and TSLP levels were measured before and after aspirin challenge in subjects with AERD (n = 25) and aspirin-tolerant asthma (ATA, n = 25) by enzyme-linked immunosorbent assay (ELISA). Pre and post-aspirin challenge levels of LTC4 and PGD2 were measured using ELISA. RESULTS: Basal plasma IL-25 levels were significantly higher in AERD group than in normal controls and in ATA group (p = 0.025 and 0.031, respectively). IL-33 and TSLP levels were comparable in the AERD and ATA groups. After the aspirin challenge, the IL-25 levels were markedly decreased in the ATA group (p = 0.024), while not changed in the AERD group. The post-challenge IL-25 levels of all asthmatic subjects were significantly correlated with aspirin challenge - induced declines in FEV1 (r = 0.357, p = 0.011), but not with basal and post challenge LTC4 and PGD2 levels. CONCLUSIONS: IL-25 is associated with bronchospasm after aspirin challenge, possibly via mechanisms other than altered LTC4 and PGD2 production.

Gene profile of fibroblasts identify relation of CCL8 with idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is characterized by the complex interaction of cells involved in chronic inflammation and fibrosis. Global gene expression of a homogenous cell population will identify novel candidate genes. METHODS: Gene expression of fibroblasts derived from lung tissues (8 IPF and 4 controls) was profiled, and ontology and functional pathway were analyzed in the genes exhibiting >2 absolute fold changes with p-values < 0.05. CCL8 mRNA and protein levels were quantified using real-time PCR and ELISA. CCL8 localization was evaluated by immunofluorescence staining. RESULTS: One hundred seventy eight genes differentially expressed and 15 genes exhibited >10-fold change. Among them, 13 were novel in relation with IPF. CCL8 expression was 22.8-fold higher in IPF fibroblasts. The levels of CCL8 mRNA and protein were 3 and 9-fold higher in 14 IPF fibroblasts than those in 10 control fibroblasts by real-time PCR and ELISA (p = 0.022 and p = 0.026, respectively). The CCL8 concentrations in BAL fluid was significantly higher in 86 patients with IPF than those in 41 controls, and other interstitial lung diseases including non-specific interstitial pneumonia (n = 22), hypersensitivity pneumonitis (n = 20) and sarcoidosis (n = 19) (p < 0.005, respectively). Cut-off values of 2.29 pg/mL and 0.43 pg/mL possessed 80.2 and 70.7% accuracy for the discrimination of IPF from NC and the other lung diseases, respectively. IPF subjects with CCL8 levels >28.61 pg/mL showed shorter survival compared to those with lower levels (p = 0.012). CCL8 was expressed by α-SMA-positive cells in the interstitium of IPF. CONCLUSIONS: Transcriptome analysis identified several novel IPF-related genes. Among them, CCL8 is a candidate molecule for the differential diagnosis and prediction of survival.

Circulating IL-33 level is associated with the progression of lung cancer.

OBJECTIVES: Interleukin (IL)-33 protects against infection and inflammation; however, few studies have explored the relevance of IL-33 in lung cancer patients. We evaluated relation of plasma IL-33 levels with development and progression of lung cancer. MATERIALS AND METHODS: A total of 160 patients with lung cancer and 160 controls with normal lungs were enrolled. Plasma IL-33 levels were measured using a specific sandwich ELISA; these levels were followed-up in 18 patients who underwent surgery and in 14 patients treated with chemotherapy. Malignant lesions and normal lung tissues from 10 cancer patients were subjected to immunohistochemical staining for IL-33. RESULTS: IL-33 levels were significantly lower in cancer patients than normal controls (0.08 vs. 0.38 ng/mL, p=0.005). Among cancer patients, IL-33 decreased in a stage-dependent manner from 0.76 ng/mL in stage I patients to 0.25 ng/mL in those with stage II, 0.08 ng/mL in those with stage III, and 0.08 ng/mL in those with stage IV (p=0.002). The levels were higher at stage I (p=0.041) and markedly lower at stages III and IV than those of controls (p=0.005 and p=0.001, respectively). A similar pattern was observed when IL-33 levels were analyzed by T stage; the levels were 0.39 ng/mL at T1/T2 vs. 0.08 ng/mL at T3/T4 (p=0.001). However, no difference was noted when stage N1 levels were compared with N2 and N3 levels (p=0.058), or between stage M0 and M1 levels (p=0.147). IL-33 levels gradually decreased after surgical resection of malignant lesions (from 1.075 to 0.756 ng/mL, p=0.006), but were unchanged after chemotherapy (0.705 vs. 0.829 ng/mL, p=0.875). On immunohistochemical staining, bronchial epithelial and vascular endothelial cells of normal lung tissues mainly expressed IL-33. CONCLUSIONS: Plasma IL-33 levels are associated inversely with progression of lung cancer. The observed decreases may be attributed to lung volume reduction containing bronchial epithelium and vascular endothelium as the sources of IL-33.

Association between TAAR6 polymorphisms and airway responsiveness to inhaled corticosteroids in asthmatic patients.

BACKGROUND: Genetic polymorphisms may be responsible for the wide variation in response to inhaled corticosteroids in asthmatic patients. We had previously reported that one polymorphism rs7772821, located on the 3'-UTR of trace amine-associated receptor 6 (TAAR6), is significantly associated with percentile changes in the forced expiratory volume in 1 s (%ΔFEV1) after inhaled corticosteroid treatment in asthmatics using a genome-wide association study. The aim of the present study was to validate the association between 15 single-nucleotide polymorphisms (SNPs) on the TAAR6 and airway responsiveness to inhaled corticosteroids in the asthmatics. METHODS: The %ΔFEV1 induced by 4 weeks' treatment with inhaled fluticasone propionate (1000 µg daily) was measured in 246 asthmatics. The 15 SNPs of TAAR6 were genotyped using a TaqMan assay. An association analysis between %ΔFEV1 and TAAR6 polymorphisms was carried out using a linear regression model controlling for age, sex, smoking status, presence of atopy, and baseline FEV1 as covariates. RESULTS: Among the 15 SNPs and seven haplotypes of TAAR6, rs7772821 (T>G) on the 3'-UTR showed the strongest correlation with inhaled corticosteroid-induced %ΔFEV1 (Pcorr=0.002 in the codominant model, Pcorr=0.03 in the dominant model, Pcorr=0.01 in the recessive model). The %ΔFEV1 of the rs7772821T>G minor homozygotes (60.77%) was higher than that of patients harboring either the rs7772821 T/G or T/T genotypes (21.32 and 31.60%, respectively). CONCLUSION: The TAAR6 rs7772821 polymorphism may be one of the important genetic factors for predicting the response to treatment with inhaled corticosteroids in asthmatics.

Exonic variants associated with development of aspirin exacerbated respiratory diseases.

Aspirin-exacerbated respiratory disease (AERD) is one phenotype of asthma, often occurring in the form of a severe and sudden attack. Due to the time-consuming nature and difficulty of oral aspirin challenge (OAC) for AERD diagnosis, non-invasive biomarkers have been sought. The aim of this study was to identify AERD-associated exonic SNPs and examine the diagnostic potential of a combination of these candidate SNPs to predict AERD. DNA from 165 AERD patients, 397 subjects with aspirin-tolerant asthma (ATA), and 398 normal controls were subjected to an Exome BeadChip assay containing 240K SNPs. 1,023 models (210-1) were generated from combinations of the top 10 SNPs, selected by the p-values in association with AERD. The area under the curve (AUC) of the receiver operating characteristic (ROC) curves was calculated for each model. SNP Function Portal and PolyPhen-2 were used to validate the functional significance of candidate SNPs. An exonic SNP, exm537513 in HLA-DPB1, showed the lowest p-value (p = 3.40×10-8) in its association with AERD risk. From the top 10 SNPs, a combination model of 7 SNPs (exm537513, exm83523, exm1884673, exm538564, exm2264237, exm396794, and exm791954) showed the best AUC of 0.75 (asymptotic p-value of 7.94×10-21), with 34% sensitivity and 93% specificity to discriminate AERD from ATA. Amino acid changes due to exm83523 in CHIA were predicted to be "probably damaging" to the structure and function of the protein, with a high score of '1'. A combination model of seven SNPs may provide a useful, non-invasive genetic marker combination for predicting AERD.