Hideyasu Yamada

Asthma Phenotypes in Japanese Adults - Their Associations with the CCL5 and ADRB2 Genotypes

BACKGROUND Cluster analyses were previously performed to identify asthma phenotypes underlying asthma syndrome. Although a large number of patients with asthma develop the disease later in life, these previous cluster analyses focused mainly patients with younger-onset asthma. METHODS Cluster analysis examined the existence of distinct phenotypes of late-onset asthma in Japanese patients with adult asthma. We then associated genotypes at the CCL5, TSLP, IL4, and ADRB2 genes with the clusters of asthma identified. RESULTS Using the 8 variables of age, sex, age at onset of the disease, smoking status, total serum IgE, %FEV(1), FEV(1)/FVC, and specific IgE responsiveness to common inhaled allergens, two-step cluster analysis of 880 Japanese adult asthma patients identified 6 phenotypes: cluster A (n = 155): older age at onset, no airflow obstruction; cluster B (n = 170): childhood onset, normal-to-mild airflow obstruction; cluster C (n = 119): childhood onset, the longest disease duration, and moderate-to-severe airflow obstruction; cluster D (n = 108): older age at onset, severe airflow obstruction; cluster E (n = 130): middle-age at onset, no airflow obstruction; and cluster F (n = 198): older age at onset, mild-to-moderate airflow obstruction. The CCL5-28C>G genotype was significantly associated with clusters A, B and D (OR 1.65, p = 0.0021; 1.67, 0.018; and 1.74, 0.011, respectively). The ADRB2 Arg16Gly genotype was also associated with clusters B and D (OR 0.47, p = 0.0004; and 0.63, 0.034, respectively). CONCLUSIONS The current cluster analysis identified meaningful adult asthma phenotypes linked to the functional CCL5 and ADRB2 genotypes. Genetic and phenotypic data have the potential to elucidate the phenotypic heterogeneity and pathophysiology of asthma.BACKGROUND Cluster analyses were previously performed to identify asthma phenotypes underlying asthma syndrome. Although a large number of patients with asthma develop the disease later in life, these previous cluster analyses focused mainly patients with younger-onset asthma. METHODS Cluster analysis examined the existence of distinct phenotypes of late-onset asthma in Japanese patients with adult asthma. We then associated genotypes at the CCL5, TSLP, IL4, and ADRB2 genes with the clusters of asthma identified. RESULTS Using the 8 variables of age, sex, age at onset of the disease, smoking status, total serum IgE, %FEV1, FEV1/FVC, and specific IgE responsiveness to common inhaled allergens, two-step cluster analysis of 880 Japanese adult asthma patients identified 6 phenotypes: cluster A (n = 155): older age at onset, no airflow obstruction; cluster B (n = 170): childhood onset, normal-to-mild airflow obstruction; cluster C (n = 119): childhood onset, the longest disease duration, and moderate-to-severe airflow obstruction; cluster D (n = 108): older age at onset, severe airflow obstruction; cluster E (n = 130): middle-age at onset, no airflow obstruction; and cluster F (n = 198): older age at onset, mild-to-moderate airflow obstruction. The CCL5-28C>G genotype was significantly associated with clusters A, B and D (OR 1.65, p = 0.0021; 1.67, 0.018; and 1.74, 0.011, respectively). The ADRB2 Arg16Gly genotype was also associated with clusters B and D (OR 0.47, p = 0.0004; and 0.63, 0.034, respectively). CONCLUSIONS The current cluster analysis identified meaningful adult asthma phenotypes linked to the functional CCL5 and ADRB2 genotypes. Genetic and phenotypic data have the potential to elucidate the pheno- typic heterogeneity and pathophysiology of asthma.

The search for common pathways underlying asthma and COPD

Recently, several genes and genetic loci associated with both asthma and chronic obstructive pulmonary disease (COPD) have been described as common susceptibility factors for the two diseases. In complex diseases such as asthma and COPD, a large number of molecular and cellular components may interact through complex networks involving gene–gene and gene–environment interactions. We sought to understand the functional and regulatory pathways that play central roles in the pathobiology of asthma and COPD and to understand the overlap between these pathways. We searched the PubMed database up to September 2012 to identify genes found to be associated with asthma, COPD, tuberculosis, or essential hypertension in at least two independent reports of candidate-gene associations or in genome-wide studies. To learn how the identified genes interact with each other and other cellular proteins, we conducted pathway-based analysis using Ingenuity Pathway Analysis software. We identified 108 genes and 58 genes that were significantly associated with asthma and COPD in at least two independent studies, respectively. These susceptibility genes were grouped into networks based on functional annotation: 12 (for asthma) and eleven (for COPD) networks were identified. Analysis of the networks for overlap between the two diseases revealed that the networks form a single complex network with 229 overlapping molecules. These overlapping molecules are significantly involved in canonical pathways including the “aryl hydrocarbon receptor signaling,” “role of cytokines in mediating communication between immune cells,” “glucocorticoid receptor signaling,” and “IL-12 signaling and production in macrophages” pathways. The Jaccard similarity index for the comparison between asthma and COPD was 0.81 for the network-level comparison, and the odds ratio was 3.62 (P < 0.0001) for the asthma/COPD pair in comparison with the tuberculosis/ essential hypertension pair. In conclusion, although the identification of asthma and COPD networks is still far from complete, these networks may be used as frameworks for integrating other genome-scale information including expression profiling and phenotypic analysis. Network overlap between asthma and COPD may indicate significant overlap between the pathobiology of these two diseases, which are thought to be genetically related.

Genome-wide association study for levels of total serum IgE identifies HLA-C in a Japanese population.

Most of the previously reported loci for total immunoglobulin E (IgE) levels are related to Th2 cell-dependent pathways. We undertook a genome-wide association study (GWAS) to identify genetic loci responsible for IgE regulation. A total of 479,940 single nucleotide polymorphisms (SNPs) were tested for association with total serum IgE levels in 1180 Japanese adults. Fine-mapping with SNP imputation demonstrated 6 candidate regions: the PYHIN1/IFI16, MHC classes I and II, LEMD2, GRAMD1B, and chr13∶60576338 regions. Replication of these candidate loci in each region was assessed in 2 independent Japanese cohorts (n = 1110 and 1364, respectively). SNP rs3130941 in the HLA-C region was consistently associated with total IgE levels in 3 independent populations, and the meta-analysis yielded genome-wide significance (P = 1.07×10−10). Using our GWAS results, we also assessed the reproducibility of previously reported gene associations with total IgE levels. Nine of 32 candidate genes identified by a literature search were associated with total IgE levels after correction for multiple testing. Our findings demonstrate that SNPs in the HLA-C region are strongly associated with total serum IgE levels in the Japanese population and that some of the previously reported genetic associations are replicated across ethnic groups.

Genomewide association study identifies HAS2 as a novel susceptibility gene for adult asthma in a Japanese population

It is increasingly clear that asthma is not a single disease, but a disorder with vast heterogeneity in pathogenesis, severity, and treatment response. To date, 30 genomewide association studies (GWASs) of asthma have been performed, including by our group. However, most gene variants identified so far confer relatively small increments in risk and explain only a small proportion of familial clustering.

Role of Lung Function Genes in the Development of Asthma

Although our previous GWAS failed to identify SNPs associated with pulmonary function at the level of genomewide significance, it did show that the heritability for FEV1/FVC was 41.6% in a Japanese population, suggesting that the heritability of pulmonary function traits can be explained by the additive effects of multiple common SNPs. In addition, our previous study indicated that pulmonary function genes identified in previous GWASs in non-Japanese populations accounted for 4.3% to 12.0% of the entire estimated heritability of FEV1/FVC in a Japanese population. Therefore, given that many loci with individual weak effects may contribute to asthma risk, in this study, we created a quantitative score of genetic load based on 16 SNPs implicated in lower lung function in both Japanese and non-Japanese populations. This genetic risk score (GRS) for lower FEV1/FVC was consistently associated with the onset of asthma (P = 9.6 × 10−4) in 2 independent Japanese populations as well as with the onset of COPD (P = 0.042). Clustering of asthma patients based on GRS levels indicated that an increased GRS may be responsible for the development of a particular phenotype of asthma characterized by early onset, atopy, and severer airflow obstruction.

Heritability of pulmonary function estimated from genome-wide SNPs in healthy Japanese adults

BACKGROUND Pulmonary function is a heritable trait, and recent genome-wide association studies (GWASs) have identified a number of loci influencing the trait. Genome-wide Complex Trait Analysis (GCTA) is a novel method provided by a software package that estimates the total additive genetic influence caused by common single nucleotide polymorphisms (SNPs) on whole-genome arrays. We conducted a GWAS and assessed the heritability of pulmonary function in an adult Japanese population using this approach. METHODS We initially conducted a GWAS on %forced vital capacity (FVC), %forced expiratory volume (FEV1) and FEV1/FVC in healthy Japanese adults (N=967). We then examined the heritability of these traits using GCTA with a total of 480,026 SNPs. We also estimated the genetic impact of the 24 genes identified as susceptibility genes to FEV1/FVC in six previous GWASs on the heritability of FEV1/FVC in the Japanese population. RESULTS The heritabilities for %FVC, %FEV1, and FEV1/FVC were 71.2%, 51.9% and 41.6%, respectively. These results corresponded to previous heritability estimates for pulmonary function obtained by GCTA or by twin studies. The 24 previously reported pulmonary function genes accounted for 4.3-12.0% of the entire estimated heritability of FEV1/FVC. CONCLUSIONS This study demonstrated that the heritability of pulmonary function traits can be explained by the additive effects of multiple common SNPs in healthy Japanese adults. The pulmonary function genes reported in previous GWASs of non-Japanese populations showed a definite impact of the genes on FEV1/FVC, thus indicating the presence of common pathways related to this trait beyond ethnicity.

Variants near the HLA complex group 22 gene (HCG22) confer increased susceptibility to late-onset asthma in Japanese populations

To the Editor: Asthma is not a single disease but rather a complex syndrome driven by various interactions among genetic and environmental factors. Recent genetic studies, including genome-wide association studies (GWASs), have successfully identified many genetic loci responsible for susceptibility to asthma. However, these loci explain only a small proportion of the heritability of asthma. This is due in part to the phenotypic heterogeneity of asthma. Several unbiased cluster analyses have classified its heterogeneous phenotypic groups; these cluster analyses, including ours, have shown that one of the strong predictors for the distinguishing features of the different phenotypic groups of asthma is age of asthma onset. In addition, we have reported that genes encoding CCL5/ RANTES, tissue factor, Clara cell secretory protein, or catalase were associatedwith adult/late-onset asthma in a Japanese population. In the current study, assuming that differentiating asthma on the basis of age of onset of the disease increases the power of genetic studies and enhances the understandingof its pathogenesis, we performed a GWAS focusing on late-onset asthma (age of onset, >_40 years) in 3 Japanese populations. We conducted a 2-stage genetic association study of 4933 Japanese adults (see Fig E1 in this article’s Online Repository at www.jacionline.org). The participants’ characteristics are shown in Table E1 in this article’s Online Repository at www.jacionline. org, and the methods are described in detail in the Methods section in this article’s Online Repository at www.jacionline. org. First, we performed a genome-widemeta-analysis of GWASs of the 2 discovery samples (see Fig E2 in this article’s Online Repository at www.jacionline.org). A total of 473,981 single nucleotide polymorphisms (SNPs) were meta-analyzed, and 14 SNPs with P values of less than 1.0 3 10 were selected (see Table

Effects of the common polymorphism in the human aldehyde dehydrogenase 2 (ALDH2) gene on the lung

BackgroundAldehyde dehydrogenases (ALDHs) play a major role in detoxification of aldehydes. High expression of ALDHs is a marker for stem cells of many organs including the lungs. A common polymorphism in ALDH2 gene (ALDH2*2) results in inactivation of the enzyme and is associated with alcohol flushing syndrome and increased risk for cardiovascular and Alzheimer’s diseases and some cancers. The effect of this ALDH2 polymorphism on the lung and its stem cells has not been thoroughly examined.MethodsWe examined the association between the ALDH2*2 allele and lung function parameters in a population of healthy individuals. We also examined its association with the incidence of asthma and COPD in patient cohorts. We used the in vitro colony forming assay to detect the effect of the polymorphism on lung epithelial stem cells from both primary human surgical samples and Aldh2*2 transgenic (Tg) and Aldh2−/− mice. Response to acute and chronic lung injuries was compared between wild type (WT), Aldh2*2 Tg and Aldh2−/− mice.ResultsIn humans, the ALDH2*2 allele was associated with lower FEV1/FVC in the general population, but not with the development of asthma or COPD. Both the bronchial and lung epithelium carrying the ALDH2*2 allele showed a tendency for lower colony forming efficiency (CFE) compared to ALDH2 allele. In mice, the tracheal epithelial thickness, nuclear density, and number of basal stem cells were significantly lower in Aldh2−/− and Aldh2*2 Tg adult mice than in WT. Electron microscopy showed significantly increased number of morphologically abnormal mitochondria in the trachea of Aldh2−/− mice. Aldh2−/− tracheal and lung cells showed higher ROS levels and fewer functional mitochondria than those from WT mice. No significant differences were detected when tracheal and lung epithelial stem cells were examined for their in vitro CFE. When exposed to chronic cigarette smoke, Aldh2*2 Tg mice were resistant to emphysema development, whereas influenza infection caused more epithelial damage in Aldh2−/− mice than in WT mice.ConclusionsALDH2 polymorphism has several subtle effects on the lungs, some of which are similar to changes observed during normal aging, suggesting a “premature lung aging” effect.

Osimertinib for an older de novo T790M patient with chronic kidney disease: Letters to the Editor

Osimertinib yielded significantly greater efficacy than did platinum therapy plus pemetrexed in patients with T790M-positive advanced non-small cell lung cancer (NSCLC; including those with central nervous system metastases) in whom the disease had progressed during first-line epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) therapy. Just 5% of the patients discontinued osimertinib owing to an adverse effect. Among the reported deaths, the only death possibly related to treatment as reported by the investigator was as a result of interstitial lung disease. An improvement or stability of the lung cancer symptoms and functioning domains of quality of life was observed with osimertinib. Owing to the increase in the incidence of lung cancer among older individuals, the efficacy and safety of EGFR-TKI for the treatment of older patients with NSCLC have recently garnered interest. Aging is associated with poor performance status. As osimertinib has finally been approved for clinical use, rebiopsies are often required in lung cancer patients who are positive for EGFR mutations and currently undergoing treatment. In this report, we present an advanced NSCLC patient who was unsuitable for chemotherapy because of chronic kidney disease (CKD) as a result of diabetes mellitus, and therefore was started on osimertinib at the standard dose of 80 mg/day. A 78-year-old woman, never smoker, was diagnosed as having stage IVA (T2aN0M1a) lung adenocarcinoma. The Eastern Cooperative Oncology Group performance status was 1. She visited our hospital for an examination of right pleural effusion. Lung adenocarcinoma was detected in the pleural effusion. The EGFR exon 21 L858R mutation and de novo T790M were identified. Treatment of patients with de novo T790M is difficult, and just a few cases have been reported. As there is no indication of osimertinib as the first-line treatment, gefitinib was selected as the initial treatment. The patient did not show any adverse effect during the initial therapy with gefitinib. After 6 months of gefitinib administration, the cancer became progressive. Before starting osimertinib (80 mg/day) when the patient was aged 79 years, the patient’s renal dysfunction was as follows: serum creatinine 1.5 mg/dL; blood urea nitrogen 24.6 mg/dL; and estimated glomerular filtration rate 26 mL/min. Twice-monthly renal function tests showed an estimated glomerular filtration rate range of between 22 and 33 mL/min (serum creatinine levels between 1.2 and 1.8 mg/dL). A total of 15 months after the start of osimertinib therapy, the patient was still well and had achieved a partial response. In the present case, the choice of EGFR-TKI was based on the need for palliative treatment. However, osimertinib therapy did not worsen the patient’s renal function, and no other severe toxicity, including rash or diarrhea, developed. Osimertinib was designed to bind covalently to EGFR, allowing it to achieve nanomolar cellular potency, and is primarily eliminated through the fecal route. To the best of our knowledge, this is the first report of an aged advanced NSCLC patient with CKD and de novo T790M resistance in whom osimertinib successfully controlled the disease. EGFR-TKI is the cornerstone for the treatment of advanced NSCLC patients with EGFR mutations. However, because most cancer drug trials exclude such patients, its utility in patients with CKD has largely been unknown. Osimertinib would not be excluded from treatment options just because of the presence of CKD.

Relationship between lung function and inhalation devices for LAMA/LABA therapy for chronic obstructive pulmonary disease:

Several devices are used for long-acting muscarinic antagonist (LAMA)/long-acting b2 agonist (LABA) inhalation therapy for chronic obstructive pulmonary disease (COPD) patients but what is the optimum device? On the basis of Bayesian network metaanalysis, all the LAMA/LABA fixed-dose combinations are at present evaluated as having similar efficacy in terms of forced expiratory volume in 1 second (FEV1). However, in recent years, the association between the residual volume and the symptoms of COPD has been drawing attention. In Japan, the devices available for LAMA/LABA are drypowder inhalers (DPIs) and soft-mist inhalers (SMIs). A previous report showed improvements in functional residual capacity and residual volume (RV) with an SMI-type LAMA/LABA over the same LABA or LAMA given as a single agent. Other researchers have reported that the deposition pattern within the lungs was more peripheral for SMI than for DPI. Since April 2015, among 9 patients in our hospital with COPD who sequentially used 2 kinds of LAMA/ LABA devices, 8 patients (mean age: 77.5 years; range: 67–87 years; mean pack years: 84.2; range: 33.8–144; all patients were male) initially took DPIglycopyrronium plus indacaterol for at least 8 weeks and then switched to SMI-tiotropium plus olodaterol. One patient switched from SMI to DPI. Because SMItiotropium plus olodaterol became commercially available 2 years after DPI-glycopyrronium plus indacaterol had become available in Japan, most patients in this study switched from DPI to SMI. All patients were using LAMA as a monotherapy before they started the combination treatment. We examined changes in lung function measures by comparing the measures taken before and after the switch to the SMI device. The first “before switch” lung function was measured on the day it was switched and the last “after switch” lung function was measured after 6 to 10 weeks. The lung function values were measured 2 to 8 hours after the last inhalation dose, and the time