Publications by authors named "Ma'en Obeidat"

75 Publications

Prioritization of candidate causal genes for asthma in susceptibility loci derived from UK Biobank.

Commun Biol 2021 06 8;4(1):700. Epub 2021 Jun 8.

Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Quebec, QC, Canada.

To identify candidate causal genes of asthma, we performed a genome-wide association study (GWAS) in UK Biobank on a broad asthma definition (n = 56,167 asthma cases and 352,255 controls). We then carried out functional mapping through transcriptome-wide association studies (TWAS) and Mendelian randomization in lung (n = 1,038) and blood (n = 31,684) tissues. The GWAS reveals 72 asthma-associated loci from 116 independent significant variants (P < 5.0E-8). The most significant lung TWAS gene on 17q12-q21 is GSDMB (P = 1.42E-54). Other TWAS genes include TSLP on 5q22, RERE on 1p36, CLEC16A on 16p13, and IL4R on 16p12, which all replicated in GTEx lung (n = 515). We demonstrate that the largest fold enrichment of regulatory and functional annotations among asthma-associated variants is in the blood. We map 485 blood eQTL-regulated genes associated with asthma and 50 of them are causal by Mendelian randomization. Prioritization of druggable genes reveals known (IL4R, TSLP, IL6, TNFSF4) and potentially new therapeutic targets for asthma.
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http://dx.doi.org/10.1038/s42003-021-02227-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8187656PMC
June 2021

Variants associated with expression have sex-differential effects on lung function.

Wellcome Open Res 2020 24;5:111. Epub 2021 May 24.

Centre for Genomic and Experimental Medicine, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, EH4 2XU, UK.

Lung function is highly heritable and differs between the sexes throughout life. However, little is known about sex-differential genetic effects on lung function. We aimed to conduct the first genome-wide genotype-by-sex interaction study on lung function to identify genetic effects that differ between males and females. We tested for interactions between 7,745,864 variants and sex on spirometry-based measures of lung function in UK Biobank (N=303,612), and sought replication in 75,696 independent individuals from the SpiroMeta consortium. Five independent single-nucleotide polymorphisms (SNPs) showed genome-wide significant (P<5x10 ) interactions with sex on lung function, and 21 showed suggestive interactions (P<1x10 ). The strongest signal, from rs7697189 (chr4:145436894) on forced expiratory volume in 1 second (FEV ) (P=3.15x10 ), was replicated (P=0.016) in SpiroMeta. The C allele increased FEV more in males (untransformed FEV β=0.028 [SE 0.0022] litres) than females (β=0.009 [SE 0.0014] litres), and this effect was not accounted for by differential effects on height, smoking or pubertal age. rs7697189 resides upstream of the hedgehog-interacting protein ( ) gene and was previously associated with lung function and lung expression. We found expression was significantly different between the sexes (P=6.90x10 ), but we could not detect sex differential effects of rs7697189 on expression. We identified a novel genotype-by-sex interaction at a putative enhancer region upstream of the gene. Establishing the mechanism by which SNPs have different effects on lung function in males and females will be important for our understanding of lung health and diseases in both sexes.
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http://dx.doi.org/10.12688/wellcomeopenres.15846.2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7938335.2PMC
May 2021

Macrophages with reduced expressions of classical M1 and M2 surface markers in human bronchoalveolar lavage fluid exhibit pro-inflammatory gene signatures.

Sci Rep 2021 04 15;11(1):8282. Epub 2021 Apr 15.

St Paul's Hospital, The University of British Columbia (UBC) Centre for Heart Lung Innovation (HLI), Vancouver, BC, Canada.

The classical M1/M2 polarity of macrophages may not be applicable to inflammatory lung diseases including chronic obstructive pulmonary disease (COPD) due to the complex microenvironment in lungs and the plasticity of macrophages. We examined macrophage sub-phenotypes in bronchoalveolar lavage (BAL) fluid in 25 participants with CD40 (a M1 marker) and CD163 (a M2 marker). Of these, we performed RNA-sequencing on each subtype in 10 patients using the Illumina NextSeq 500. Approximately 25% of the macrophages did not harbor classical M1 or M2 surface markers (double negative, DN), and these cells were significantly enriched in COPD patients compared with non-COPD patients (46.7% vs. 14.5%, p < 0.001). 1886 genes were differentially expressed in the DN subtype compared with  all other subtypes at a 10% false discovery rate. The 602 up-regulated genes included 15 mitochondrial genes and were enriched in 86 gene ontology (GO) biological processes including inflammatory responses. Modules associated with cellular functions including oxidative phosphorylation were significantly down-regulated in the DN subtype. Macrophages in the human BAL fluid, which were negative for both M1/M2 surface markers, harbored a gene signature that was pro-inflammatory and suggested dysfunction in cellular homeostasis. These macrophages may contribute to the pathogenesis and manifestations of inflammatory lung diseases such as COPD.
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http://dx.doi.org/10.1038/s41598-021-87720-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8050093PMC
April 2021

Genome-wide association meta-analysis identifies pleiotropic risk loci for aerodigestive squamous cell cancers.

PLoS Genet 2021 03 5;17(3):e1009254. Epub 2021 Mar 5.

University of Salzburg, Department of Biosciences and Cancer Cluster Salzburg, Salzburg, Austria.

Squamous cell carcinomas (SqCC) of the aerodigestive tract have similar etiological risk factors. Although genetic risk variants for individual cancers have been identified, an agnostic, genome-wide search for shared genetic susceptibility has not been performed. To identify novel and pleotropic SqCC risk variants, we performed a meta-analysis of GWAS data on lung SqCC (LuSqCC), oro/pharyngeal SqCC (OSqCC), laryngeal SqCC (LaSqCC) and esophageal SqCC (ESqCC) cancers, totaling 13,887 cases and 61,961 controls of European ancestry. We identified one novel genome-wide significant (Pmeta<5x10-8) aerodigestive SqCC susceptibility loci in the 2q33.1 region (rs56321285, TMEM273). Additionally, three previously unknown loci reached suggestive significance (Pmeta<5x10-7): 1q32.1 (rs12133735, near MDM4), 5q31.2 (rs13181561, TMEM173) and 19p13.11 (rs61494113, ABHD8). Multiple previously identified loci for aerodigestive SqCC also showed evidence of pleiotropy in at least another SqCC site, these include: 4q23 (ADH1B), 6p21.33 (STK19), 6p21.32 (HLA-DQB1), 9p21.33 (CDKN2B-AS1) and 13q13.1(BRCA2). Gene-based association and gene set enrichment identified a set of 48 SqCC-related genes rel to DNA damage and epigenetic regulation pathways. Our study highlights the importance of cross-cancer analyses to identify pleiotropic risk loci of histology-related cancers arising at distinct anatomical sites.
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http://dx.doi.org/10.1371/journal.pgen.1009254DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7968735PMC
March 2021

Aryl hydrocarbon receptor deficiency causes the development of chronic obstructive pulmonary disease through the integration of multiple pathogenic mechanisms.

FASEB J 2021 03;35(3):e21376

Research Institute of the McGill University Health Centre, Montreal, QC, Canada.

Emphysema, a component of chronic obstructive pulmonary disease (COPD), is characterized by irreversible alveolar destruction that results in a progressive decline in lung function. This alveolar destruction is caused by cigarette smoke, the most important risk factor for COPD. Only 15%-20% of smokers develop COPD, suggesting that unknown factors contribute to disease pathogenesis. We postulate that the aryl hydrocarbon receptor (AHR), a receptor/transcription factor highly expressed in the lungs, may be a new susceptibility factor whose expression protects against COPD. Here, we report that Ahr-deficient mice chronically exposed to cigarette smoke develop airspace enlargement concomitant with a decline in lung function. Chronic cigarette smoke exposure also increased cleaved caspase-3, lowered SOD2 expression, and altered MMP9 and TIMP-1 levels in Ahr-deficient mice. We also show that people with COPD have reduced expression of pulmonary and systemic AHR, with systemic AHR mRNA levels positively correlating with lung function. Systemic AHR was also lower in never-smokers with COPD. Thus, AHR expression protects against the development of COPD by controlling interrelated mechanisms involved in the pathogenesis of this disease. This study identifies the AHR as a new, central player in the homeostatic maintenance of lung health, providing a foundation for the AHR as a novel therapeutic target and/or predictive biomarker in chronic lung disease.
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http://dx.doi.org/10.1096/fj.202002350RDOI Listing
March 2021

Genetic regulation of gene expression of MIF family members in lung tissue.

Sci Rep 2020 10 12;10(1):16980. Epub 2020 Oct 12.

Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, Groningen, The Netherlands.

Macrophage migration inhibitory factor (MIF) is a cytokine found to be associated with chronic obstructive pulmonary disease (COPD). However, there is no consensus on how MIF levels differ in COPD compared to control conditions and there are no reports on MIF expression in lung tissue. Here we studied gene expression of members of the MIF family MIF, D-Dopachrome Tautomerase (DDT) and DDT-like (DDTL) in a lung tissue dataset with 1087 subjects and identified single nucleotide polymorphisms (SNPs) regulating their gene expression. We found higher MIF and DDT expression in COPD patients compared to non-COPD subjects and found 71 SNPs significantly influencing gene expression of MIF and DDTL. Furthermore, the platform used to measure MIF (microarray or RNAseq) was found to influence the splice variants detected and subsequently the direction of the SNP effects on MIF expression. Among the SNPs found to regulate MIF expression, the major LD block identified was linked to rs5844572, a SNP previously found to be associated with lower diffusion capacity in COPD. This suggests that MIF may be contributing to the pathogenesis of COPD, as SNPs that influence MIF expression are also associated with symptoms of COPD. Our study shows that MIF levels are affected not only by disease but also by genetic diversity (i.e. SNPs). Since none of our significant eSNPs for MIF or DDTL have been described in GWAS for COPD or lung function, MIF expression in COPD patients is more likely a consequence of disease-related factors rather than a cause of the disease.
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http://dx.doi.org/10.1038/s41598-020-74121-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7552402PMC
October 2020

TWIST1 DNA methylation is a cell marker of airway and parenchymal lung fibroblasts that are differentially methylated in asthma.

Clin Epigenetics 2020 10 2;12(1):145. Epub 2020 Oct 2.

Centre for Heart Lung Innovation, University of British Columbia, Vancouver, Canada.

Background: Mesenchymal fibroblasts are ubiquitous cells that maintain the extracellular matrix of organs. Within the lung, airway and parenchymal fibroblasts are crucial for lung development and are altered with disease, but it has been difficult to understand their roles due to the lack of distinct molecular markers. We studied genome-wide DNA methylation and gene expression in airway and parenchymal lung fibroblasts from healthy and asthmatic donors, to identify a robust cell marker and to determine if these cells are molecularly distinct in asthma.

Results: Airway (N = 8) and parenchymal (N = 15) lung fibroblasts from healthy individuals differed in the expression of 158 genes, and DNA methylation of 3936 CpGs (Bonferroni adjusted p value < 0.05). Differential DNA methylation between cell types was associated with differential expression of 42 genes, but no single DNA methylation CpG feature (location, effect size, number) defined the interaction. Replication of gene expression and DNA methylation in a second cohort identified TWIST1 gene expression, DNA methylation and protein expression as a cell marker of airway and parenchymal lung fibroblasts, with DNA methylation having 100% predictive discriminatory power. DNA methylation was differentially altered in parenchymal (112 regions) and airway fibroblasts (17 regions) with asthmatic status, with no overlap between regions.

Conclusions: Differential methylation of TWIST1 is a robust cell marker of airway and parenchymal lung fibroblasts. Airway and parenchymal fibroblast DNA methylation are differentially altered in individuals with asthma, and the role of both cell types should be considered in the pathogenesis of asthma.
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http://dx.doi.org/10.1186/s13148-020-00931-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7531162PMC
October 2020

Occurrence of Accelerated Epigenetic Aging and Methylation Disruptions in Human Immunodeficiency Virus Infection Before Antiretroviral Therapy.

J Infect Dis 2021 May;223(10):1681-1689

Centre for Heart Lung Innovation, University of British Columbia, Vancouver, British Columbia, Canada.

Background: Whether accelerated aging develops over the course of chronic human immunodeficiency virus (HIV) infection or can be observed before significant immunosuppression on is unknown. We studied DNA methylation in blood to estimate cellular aging in persons living with HIV (PLWH) before the initiation of antiretroviral therapy (ART).

Methods: A total of 378 ART-naive PLWH who had CD4 T-cell counts >500/µL and were enrolled in the Strategic Timing of Antiretroviral Therapy trial (Pulmonary Substudy) were compared with 34 HIV-negative controls. DNA methylation was performed using the Illumina MethylationEPIC BeadChip. Differentially methylated positions (DMPs) and differentially methylated regions (DMRs) in PLWH compared with controls were identified using a robust linear model. Methylation age was calculated using a previously described epigenetic clock.

Results: There were a total of 56 639 DMPs and 6103 DMRs at a false discovery rate of <0.1. The top 5 DMPs corresponded to genes NLRC5, VRK2, B2M, and GPR6 and were highly enriched for cancer-related pathways. PLWH had significantly higher methylation age than HIV-negative controls (P = .001), with black race, low CD4 and high CD8 T-cell counts, and duration of HIV being risk factors for age acceleration.

Conclusions: PLWH before the initiation of ART and with preserved immune status show evidence of advanced methylation aging.
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http://dx.doi.org/10.1093/infdis/jiaa599DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8161637PMC
May 2021

Chronic obstructive pulmonary disease and related phenotypes: polygenic risk scores in population-based and case-control cohorts.

Lancet Respir Med 2020 07;8(7):696-708

Division of Pulmonary, Critical Care, and Sleep Medicine, National Jewish Health, Denver, CO, USA.

Background: Genetic factors influence chronic obstructive pulmonary disease (COPD) risk, but the individual variants that have been identified have small effects. We hypothesised that a polygenic risk score using additional variants would predict COPD and associated phenotypes.

Methods: We constructed a polygenic risk score using a genome-wide association study of lung function (FEV and FEV/forced vital capacity [FVC]) from the UK Biobank and SpiroMeta. We tested this polygenic risk score in nine cohorts of multiple ethnicities for an association with moderate-to-severe COPD (defined as FEV/FVC <0·7 and FEV <80% of predicted). Associations were tested using logistic regression models, adjusting for age, sex, height, smoking pack-years, and principal components of genetic ancestry. We assessed predictive performance of models by area under the curve. In a subset of studies, we also studied quantitative and qualitative CT imaging phenotypes that reflect parenchymal and airway pathology, and patterns of reduced lung growth.

Findings: The polygenic risk score was associated with COPD in European (odds ratio [OR] per SD 1·81 [95% CI 1·74-1·88] and non-European (1·42 [1·34-1·51]) populations. Compared with the first decile, the tenth decile of the polygenic risk score was associated with COPD, with an OR of 7·99 (6·56-9·72) in European ancestry and 4·83 (3·45-6·77) in non-European ancestry cohorts. The polygenic risk score was superior to previously described genetic risk scores and, when combined with clinical risk factors (ie, age, sex, and smoking pack-years), showed improved prediction for COPD compared with a model comprising clinical risk factors alone (AUC 0·80 [0·79-0·81] vs 0·76 [0·75-0·76]). The polygenic risk score was associated with CT imaging phenotypes, including wall area percent, quantitative and qualitative measures of emphysema, local histogram emphysema patterns, and destructive emphysema subtypes. The polygenic risk score was associated with a reduced lung growth pattern.

Interpretation: A risk score comprised of genetic variants can identify a small subset of individuals at markedly increased risk for moderate-to-severe COPD, emphysema subtypes associated with cigarette smoking, and patterns of reduced lung growth.

Funding: US National Institutes of Health, Wellcome Trust.
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http://dx.doi.org/10.1016/S2213-2600(20)30101-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7429152PMC
July 2020

Phenotypic and functional translation of IL33 genetics in asthma.

J Allergy Clin Immunol 2021 01 19;147(1):144-157. Epub 2020 May 19.

Department of Health Sciences, University of Leicester, Leicester, United Kingdom; National Institute for Health Research Leicester Respiratory Biomedical Research Centre, Leicester, United Kingdom.

Background: Asthma is a complex disease with multiple phenotypes that may differ in disease pathobiology and treatment response. IL33 single nucleotide polymorphisms (SNPs) have been reproducibly associated with asthma. IL33 levels are elevated in sputum and bronchial biopsies of patients with asthma. The functional consequences of IL33 asthma SNPs remain unknown.

Objective: This study sought to determine whether IL33 SNPs associate with asthma-related phenotypes and with IL33 expression in lung or bronchial epithelium. This study investigated the effect of increased IL33 expression on human bronchial epithelial cell (HBEC) function.

Methods: Association between IL33 SNPs (Chr9: 5,815,786-6,657,983) and asthma phenotypes (Lifelines/DAG [Dutch Asthma GWAS]/GASP [Genetics of Asthma Severity & Phenotypes] cohorts) and between SNPs and expression (lung tissue, bronchial brushes, HBECs) was done using regression modeling. Lentiviral overexpression was used to study IL33 effects on HBECs.

Results: We found that 161 SNPs spanning the IL33 region associated with 1 or more asthma phenotypes after correction for multiple testing. We report a main independent signal tagged by rs992969 associating with blood eosinophil levels, asthma, and eosinophilic asthma. A second, independent signal tagged by rs4008366 presented modest association with eosinophilic asthma. Neither signal associated with FEV, FEV/forced vital capacity, atopy, and age of asthma onset. The 2 IL33 signals are expression quantitative loci in bronchial brushes and cultured HBECs, but not in lung tissue. IL33 overexpression in vitro resulted in reduced viability and reactive oxygen species-capturing of HBECs, without influencing epithelial cell count, metabolic activity, or barrier function.

Conclusions: We identify IL33 as an epithelial susceptibility gene for eosinophilia and asthma, provide mechanistic insight, and implicate targeting of the IL33 pathway specifically in eosinophilic asthma.
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http://dx.doi.org/10.1016/j.jaci.2020.04.051DOI Listing
January 2021

Protein-altering germline mutations implicate novel genes related to lung cancer development.

Nat Commun 2020 05 11;11(1):2220. Epub 2020 May 11.

Radboud University Medical Center, Radboud Institute for Health Sciences, Nijmegen, The Netherlands.

Few germline mutations are known to affect lung cancer risk. We performed analyses of rare variants from 39,146 individuals of European ancestry and investigated gene expression levels in 7,773 samples. We find a large-effect association with an ATM L2307F (rs56009889) mutation in adenocarcinoma for discovery (adjusted Odds Ratio = 8.82, P = 1.18 × 10) and replication (adjusted OR = 2.93, P = 2.22 × 10) that is more pronounced in females (adjusted OR = 6.81 and 3.19 and for discovery and replication). We observe an excess loss of heterozygosity in lung tumors among ATM L2307F allele carriers. L2307F is more frequent (4%) among Ashkenazi Jewish populations. We also observe an association in discovery (adjusted OR = 2.61, P = 7.98 × 10) and replication datasets (adjusted OR = 1.55, P = 0.06) with a loss-of-function mutation, Q4X (rs150665432) of an uncharacterized gene, KIAA0930. Our findings implicate germline genetic variants in ATM with lung cancer susceptibility and suggest KIAA0930 as a novel candidate gene for lung cancer risk.
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http://dx.doi.org/10.1038/s41467-020-15905-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7214407PMC
May 2020

Phenotypic and functional translation of IL1RL1 locus polymorphisms in lung tissue and asthmatic airway epithelium.

JCI Insight 2020 04 23;5(8). Epub 2020 Apr 23.

Department of Human Development and.

The IL1RL1 (ST2) gene locus is robustly associated with asthma; however, the contribution of single nucleotide polymorphisms (SNPs) in this locus to specific asthma subtypes and the functional mechanisms underlying these associations remain to be defined. We tested for association between IL1RL1 region SNPs and characteristics of asthma as defined by clinical and immunological measures and addressed functional effects of these genetic variants in lung tissue and airway epithelium. Utilizing 4 independent cohorts (Lifelines, Dutch Asthma GWAS [DAG], Genetics of Asthma Severity and Phenotypes [GASP], and Manchester Asthma and Allergy Study [MAAS]) and resequencing data, we identified 3 key signals associated with asthma features. Investigations in lung tissue and primary bronchial epithelial cells identified context-dependent relationships between the signals and IL1RL1 mRNA and soluble protein expression. This was also observed for asthma-associated IL1RL1 nonsynonymous coding TIR domain SNPs. Bronchial epithelial cell cultures from asthma patients, exposed to exacerbation-relevant stimulations, revealed modulatory effects for all 4 signals on IL1RL1 mRNA and/or protein expression, suggesting SNP-environment interactions. The IL1RL1 TIR signaling domain haplotype affected IL-33-driven NF-κB signaling, while not interfering with TLR signaling. In summary, we identify that IL1RL1 genetic signals potentially contribute to severe and eosinophilic phenotypes in asthma, as well as provide initial mechanistic insight, including genetic regulation of IL1RL1 isoform expression and receptor signaling.
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http://dx.doi.org/10.1172/jci.insight.132446DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7205441PMC
April 2020

Immune-mediated genetic pathways resulting in pulmonary function impairment increase lung cancer susceptibility.

Nat Commun 2020 01 7;11(1):27. Epub 2020 Jan 7.

BC Cancer Agency, Vancouver, BC, Canada.

Impaired lung function is often caused by cigarette smoking, making it challenging to disentangle its role in lung cancer susceptibility. Investigation of the shared genetic basis of these phenotypes in the UK Biobank and International Lung Cancer Consortium (29,266 cases, 56,450 controls) shows that lung cancer is genetically correlated with reduced forced expiratory volume in one second (FEV: r = 0.098, p = 2.3 × 10) and the ratio of FEV to forced vital capacity (FEV/FVC: r = 0.137, p = 2.0 × 10). Mendelian randomization analyses demonstrate that reduced FEV increases squamous cell carcinoma risk (odds ratio (OR) = 1.51, 95% confidence intervals: 1.21-1.88), while reduced FEV/FVC increases the risk of adenocarcinoma (OR = 1.17, 1.01-1.35) and lung cancer in never smokers (OR = 1.56, 1.05-2.30). These findings support a causal role of pulmonary impairment in lung cancer etiology. Integrative analyses reveal that pulmonary function instruments, including 73 novel variants, influence lung tissue gene expression and implicate immune-related pathways in mediating the observed effects on lung carcinogenesis.
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http://dx.doi.org/10.1038/s41467-019-13855-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6946810PMC
January 2020

Widespread Sexual Dimorphism in the Transcriptome of Human Airway Epithelium in Response to Smoking.

Sci Rep 2019 11 26;9(1):17600. Epub 2019 Nov 26.

The University of British Columbia Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada.

Epidemiological studies have shown that female smokers are at higher risk of chronic obstructive pulmonary disease (COPD). Female patients have worse symptoms and health status and increased risk of exacerbations. We determined the differences in the transcriptome of the airway epithelium between males and females, as well the sex-by-smoking interaction. We processed public gene expression data of human airway epithelium into a discovery cohort of 211 subjects (never smokers n = 68; current smokers n = 143) and two replication cohorts of 104 subjects (21 never, 52 current, and 31 former smokers) and 238 subjects (99 current and 139 former smokers. We analyzed gene differential expression with smoking status, sex, and smoking-by-sex interaction and used network approaches for modules' level analyses. We identified and replicated two differentially expressed modules between the sexes in response to smoking with genes located throughout the autosomes and not restricted to sex chromosomes. The two modules were enriched in autophagy (up-regulated in female smokers) and response to virus and type 1 interferon signaling pathways which were down-regulated in female smokers compared to males. The results offer insights into the molecular mechanisms of the sexually dimorphic effect of smoking, potentially enabling a precision medicine approach to smoking related lung diseases.
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http://dx.doi.org/10.1038/s41598-019-54051-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6879662PMC
November 2019

Genome-Wide Association Study of Susceptibility to Idiopathic Pulmonary Fibrosis.

Am J Respir Crit Care Med 2020 03;201(5):564-574

Section of Pulmonary, Critical Care and Sleep Medicine, Yale School of Medicine, New Haven, Connecticut.

Idiopathic pulmonary fibrosis (IPF) is a complex lung disease characterized by scarring of the lung that is believed to result from an atypical response to injury of the epithelium. Genome-wide association studies have reported signals of association implicating multiple pathways including host defense, telomere maintenance, signaling, and cell-cell adhesion. To improve our understanding of factors that increase IPF susceptibility by identifying previously unreported genetic associations. We conducted genome-wide analyses across three independent studies and meta-analyzed these results to generate the largest genome-wide association study of IPF to date (2,668 IPF cases and 8,591 controls). We performed replication in two independent studies (1,456 IPF cases and 11,874 controls) and functional analyses (including statistical fine-mapping, investigations into gene expression, and testing for enrichment of IPF susceptibility signals in regulatory regions) to determine putatively causal genes. Polygenic risk scores were used to assess the collective effect of variants not reported as associated with IPF. We identified and replicated three new genome-wide significant ( < 5 × 10) signals of association with IPF susceptibility (associated with altered gene expression of , , and ) and confirmed associations at 11 previously reported loci. Polygenic risk score analyses showed that the combined effect of many thousands of as yet unreported IPF susceptibility variants contribute to IPF susceptibility. The observation that decreased expression associates with increased susceptibility to IPF supports recent studies demonstrating the importance of mTOR signaling in lung fibrosis. New signals of association implicating and suggest a possible role of mitotic spindle-assembly genes in IPF susceptibility.
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http://dx.doi.org/10.1164/rccm.201905-1017OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7047454PMC
March 2020

Transcriptome-wide association study reveals candidate causal genes for lung cancer.

Int J Cancer 2020 04 9;146(7):1862-1878. Epub 2019 Dec 9.

Epidemiology Division, Princess Margaret Cancer Center, Toronto, ON, Canada.

We have recently completed the largest GWAS on lung cancer including 29,266 cases and 56,450 controls of European descent. The goal of our study has been to integrate the complete GWAS results with a large-scale expression quantitative trait loci (eQTL) mapping study in human lung tissues (n = 1,038) to identify candidate causal genes for lung cancer. We performed transcriptome-wide association study (TWAS) for lung cancer overall, by histology (adenocarcinoma, squamous cell carcinoma and small cell lung cancer) and smoking subgroups (never- and ever-smokers). We performed replication analysis using lung data from the Genotype-Tissue Expression (GTEx) project. DNA damage assays were performed in human lung fibroblasts for selected TWAS genes. As expected, the main TWAS signal for all histological subtypes and ever-smokers was on chromosome 15q25. The gene most strongly associated with lung cancer at this locus using the TWAS approach was IREB2 (p = 1.09E-99), where lower predicted expression increased lung cancer risk. A new lung adenocarcinoma susceptibility locus was revealed on 9p13.3 and associated with higher predicted expression of AQP3 (p = 3.72E-6). Among the 45 previously described lung cancer GWAS loci, we mapped candidate target gene for 17 of them. The association AQP3-adenocarcinoma on 9p13.3 was replicated using GTEx (p = 6.55E-5). Consistent with the effect of risk alleles on gene expression levels, IREB2 knockdown and AQP3 overproduction promote endogenous DNA damage. These findings indicate genes whose expression in lung tissue directly influences lung cancer risk.
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http://dx.doi.org/10.1002/ijc.32771DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7008463PMC
April 2020

BMI is associated with FEV decline in chronic obstructive pulmonary disease: a meta-analysis of clinical trials.

Respir Res 2019 Oct 29;20(1):236. Epub 2019 Oct 29.

Centre for Heart Lung Innovation, St. Paul's Hospital & Division of Respiratory Medicine, University of British Columbia, Rm 166-1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada.

Background: There is considerable heterogeneity in the rate of lung function decline in chronic obstructive pulmonary disease (COPD), the determinants of which are largely unknown. Observational studies in COPD indicate that low body mass index (BMI) is associated with worse outcomes, and overweight/obesity has a protective effect - the so-called "obesity paradox". We aimed to determine the relationship between BMI and the rate of FEV decline in data from published clinical trials in COPD.

Methods: We performed a systematic review of the literature, and identified 5 randomized controlled trials reporting the association between BMI and FEV decline. Four of these were included in the meta-analyses. We analyzed BMI in 4 categories: BMI-I (< 18.5 or <  20 kg/m), BMI-II (18.5 or 20 to < 25 kg/m), BMI-III (25 to < 29 or < 30 kg/m) and BMI-IV (≥29 or ≥ 30 kg/m). We then performed a meta-regression of all the estimates against the BMI category.

Results: The estimated rate of FEV decline decreased with increasing BMI. Meta-regression of the estimates showed that BMI was significantly associated with the rate of FEV decline (linear trend p = 1.21 × 10).

Conclusions: These novel findings support the obesity paradox in COPD: compared to normal BMI, low BMI is a risk factor for accelerated lung function decline, whilst high BMI has a protective effect. The relationship may be due to common but as-of-yet unknown causative factors; further investigation into which may reveal novel endotypes or targets for therapeutic intervention.
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http://dx.doi.org/10.1186/s12931-019-1209-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6819522PMC
October 2019

The pharmacogenomics of inhaled corticosteroids and lung function decline in COPD.

Eur Respir J 2019 12 4;54(6). Epub 2019 Dec 4.

The University of British Columbia Center for Heart Lung Innovation, St Paul's Hospital Vancouver, BC, Canada.

Inhaled corticosteroids (ICS) are widely prescribed for patients with chronic obstructive pulmonary disease (COPD), yet have variable outcomes and adverse reactions, which may be genetically determined. The primary aim of the study was to identify the genetic determinants for forced expiratory volume in 1 s (FEV) changes related to ICS therapy.In the Lung Health Study (LHS)-2, 1116 COPD patients were randomised to the ICS triamcinolone acetonide (n=559) or placebo (n=557) with spirometry performed every 6 months for 3 years. We performed a pharmacogenomic genome-wide association study for the genotype-by-ICS treatment effect on 3 years of FEV changes (estimated as slope) in 802 genotyped LHS-2 participants. Replication was performed in 199 COPD patients randomised to the ICS, fluticasone or placebo.A total of five loci showed genotype-by-ICS interaction at p<5×10; of these, single nucleotide polymorphism (SNP) rs111720447 on chromosome 7 was replicated (discovery p=4.8×10, replication p=5.9×10) with the same direction of interaction effect. ENCODE (Encyclopedia of DNA Elements) data revealed that in glucocorticoid-treated (dexamethasone) A549 alveolar cell line, glucocorticoid receptor binding sites were located near SNP rs111720447. In stratified analyses of LHS-2, genotype at SNP rs111720447 was significantly associated with rate of FEV decline in patients taking ICS (C allele β 56.36 mL·year, 95% CI 29.96-82.76 mL·year) and in patients who were assigned to placebo, although the relationship was weaker and in the opposite direction to that in the ICS group (C allele β -27.57 mL·year, 95% CI -53.27- -1.87 mL·year).The study uncovered genetic factors associated with FEV changes related to ICS in COPD patients, which may provide new insight on the potential biology of steroid responsiveness in COPD.
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http://dx.doi.org/10.1183/13993003.00521-2019DOI Listing
December 2019

Effect of short-term oral prednisone therapy on blood gene expression: a randomised controlled clinical trial.

Respir Res 2019 Aug 5;20(1):176. Epub 2019 Aug 5.

The University of British Columbia Centre for Heart Lung Innovation (HLI), St Paul's Hospital, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada.

Background: Effects of systemic corticosteroids on blood gene expression are largely unknown. This study determined gene expression signature associated with short-term oral prednisone therapy in patients with chronic obstructive pulmonary disease (COPD) and its relationship to 1-year mortality following an acute exacerbation of COPD (AECOPD).

Methods: Gene expression in whole blood was profiled using the Affymetrix Human Gene 1.1 ST microarray chips from two cohorts: 1) a prednisone cohort with 37 stable COPD patients randomly assigned to prednisone 30 mg/d + standard therapy for 4 days or standard therapy alone and 2) the Rapid Transition Program (RTP) cohort with 218 COPD patients who experienced AECOPD and were treated with systemic corticosteroids. All gene expression data were adjusted for the total number of white blood cells and their differential cell counts.

Results: In the prednisone cohort, 51 genes were differentially expressed between prednisone and standard therapy group at a false discovery rate of < 0.05. The top 3 genes with the largest fold-changes were KLRF1, GZMH and ADGRG1; and 21 genes were significantly enriched in immune system pathways including the natural killer cell mediated cytotoxicity. In the RTP cohort, 27 patients (12.4%) died within 1 year after hospitalisation of AECOPD; 32 of 51 genes differentially expressed in the prednisone cohort significantly changed from AECOPD to the convalescent state and were enriched in similar cellular immune pathways to that in the prednisone cohort. Of these, 10 genes including CX3CR1, KLRD1, S1PR5 and PRF1 were significantly associated with 1-year mortality.

Conclusions: Short-term daily prednisone therapy produces a distinct blood gene signature that may be used to determine and monitor treatment responses to prednisone in COPD patients during AECOPD.

Trial Registration: The prednisone cohort was registered at clinicalTrials.gov ( NCT02534402 ) and the RTP cohort was registered at ClinicalTrials.gov ( NCT02050022 ).
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http://dx.doi.org/10.1186/s12931-019-1147-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6683462PMC
August 2019

Precision health: treating the individual patient with chronic obstructive pulmonary disease.

Med J Aust 2019 05 11;210(9):424-428. Epub 2019 Apr 11.

University of British Columbia, Vancouver, Canada.

Chronic obstructive pulmonary disease (COPD) is defined based on a reduced ratio of forced expiratory volume in one second (FEV ) to forced vital capacity (FVC) on spirometry. However, within this definition, there is significant heterogeneity of pathophysiological processes that lead to airflow obstruction and variation in phenotypic manifestations across patients. Current pharmacological treatments are based on large randomised clinical trials that apply to an "average" patient. Precision health enables tailoring of treatment for each individual patient by taking into account their unique characteristics. The number needed to treat (NNT) metric is often used to define implementation of precision health for specific interventions, with common endpoints requiring an NNT ≤ 5 to achieve precision therapy. Higher NNTs may be acceptable for rare but important endpoints such as mortality. Long-acting muscarinic antagonists and inhaled corticosteroids, which are commonly used in COPD, have 1-year treatment NNTs between 15 and 20 for exacerbation prevention in unselected patients with COPD. Subgroup identification using biomarkers or clinical traits may enable precision health. For example, NNT for inhaled corticosteroids is 9 in patients with a blood eosinophil count ≥ 300 cells/μL and 8 for long-acting muscarinic antagonists in patients with a body mass index ≤ 20 kg/m . Lung volume reduction surgery is associated with an NNT of 6 for survival over 5 years in patients with upper lobe-predominant disease and low exercise capacity (whereas the NNT is 245 when no bioimaging or exercise markers are used). Continuous domiciliary oxygen therapy (for at least 15 hours/day) has an NNT of 5 for survival over 5 years in patients with resting hypoxemia (PaO  < 60 mmHg on room air). Emerging areas of precision health in COPD with potential for low NNTs in specific circumstances include anti-interleukin-5 therapy for eosinophilic COPD, and immunoglobulin replacement therapy for patients with severe immunoglobulin deficiency.
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http://dx.doi.org/10.5694/mja2.50138DOI Listing
May 2019

Genetic landscape of chronic obstructive pulmonary disease identifies heterogeneous cell-type and phenotype associations.

Nat Genet 2019 03 25;51(3):494-505. Epub 2019 Feb 25.

Department of Internal Medicine and Environmental Health Center, School of Medicine, Kangwon National University, Chuncheon, South Korea.

Chronic obstructive pulmonary disease (COPD) is the leading cause of respiratory mortality worldwide. Genetic risk loci provide new insights into disease pathogenesis. We performed a genome-wide association study in 35,735 cases and 222,076 controls from the UK Biobank and additional studies from the International COPD Genetics Consortium. We identified 82 loci associated with P < 5 × 10; 47 of these were previously described in association with either COPD or population-based measures of lung function. Of the remaining 35 new loci, 13 were associated with lung function in 79,055 individuals from the SpiroMeta consortium. Using gene expression and regulation data, we identified functional enrichment of COPD risk loci in lung tissue, smooth muscle, and several lung cell types. We found 14 COPD loci shared with either asthma or pulmonary fibrosis. COPD genetic risk loci clustered into groups based on associations with quantitative imaging features and comorbidities. Our analyses provide further support for the genetic susceptibility and heterogeneity of COPD.
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http://dx.doi.org/10.1038/s41588-018-0342-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6546635PMC
March 2019

New genetic signals for lung function highlight pathways and chronic obstructive pulmonary disease associations across multiple ancestries.

Nat Genet 2019 03 25;51(3):481-493. Epub 2019 Feb 25.

Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK.

Reduced lung function predicts mortality and is key to the diagnosis of chronic obstructive pulmonary disease (COPD). In a genome-wide association study in 400,102 individuals of European ancestry, we define 279 lung function signals, 139 of which are new. In combination, these variants strongly predict COPD in independent populations. Furthermore, the combined effect of these variants showed generalizability across smokers and never smokers, and across ancestral groups. We highlight biological pathways, known and potential drug targets for COPD and, in phenome-wide association studies, autoimmune-related and other pleiotropic effects of lung function-associated variants. This new genetic evidence has potential to improve future preventive and therapeutic strategies for COPD.
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http://dx.doi.org/10.1038/s41588-018-0321-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6397078PMC
March 2019

Introduction to precision medicine in COPD.

Eur Respir J 2019 04 11;53(4). Epub 2019 Apr 11.

UBC Centre for Heart Lung Innovation, University of British Columbia and St. Paul's Hospital, Vancouver, BC, Canada.

Although there has been tremendous growth in our understanding of chronic obstructive pulmonary disease (COPD) and its pathophysiology over the past few decades, the pace of therapeutic innovation has been extremely slow. COPD is now widely accepted as a heterogeneous condition with multiple phenotypes and endotypes. Thus, there is a pressing need for COPD care to move from the current "one-size-fits-all" approach to a precision medicine approach that takes into account individual patient variability in genes, environment and lifestyle. Precision medicine is enabled by biomarkers that can: 1) accurately identify subgroups of patients who are most likely to benefit from therapeutics and those who will only experience harm (predictive biomarkers); 2) predict therapeutic responses to drugs at an individual level (response biomarkers); and 3) segregate patients who are at risk of poor outcomes from those who have relatively stable disease (prognostic biomarkers). In this essay, we will discuss the current concept of precision medicine and its relevance for COPD and explore ways to implement precision medicine for millions of patients across the world with COPD.
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http://dx.doi.org/10.1183/13993003.02460-2018DOI Listing
April 2019

Lung cancer susceptibility genetic variants modulate HOXB2 expression in the lung.

Int J Dev Biol 2018 ;62(11-12):857-864

Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada.

The HOX genes are transcription factors that are expressed in coordinated spatiotemporal patterns to ensure normal development. Ectopic expression may instead lead to the development and progression of tumors. Genetic polymorphisms in the regions of four HOX gene clusters were tested for association with lung cancer in 420 cases and 3,151 controls. The effect of these variants on lung gene expression (expression quantitative trait loci, eQTL) was tested in a discovery set of 409 non-tumor lung samples and validated in two lung eQTL replication sets (n = 287 and 342). The expression levels of HOXB2 were evaluated at the mRNA and protein levels by quantitative real-time PCR and immunohistochemistry in paired tumor and non-tumor lung tissue samples. The most significant SNP associated with lung cancer in the HOXB cluster was rs10853100 located upstream of the HOXB cluster. HOXB2 was the top eQTL-regulated gene with several polymorphisms associated with its mRNA expression levels in lung tissue. This includes the lung cancer SNP rs10853100 that was significantly associated with HOXB2 expression (P=3.39E-7). In the lung eQTL discovery and replication sets, the lung cancer risk allele (T) for rs10853100 was associated with lower HOXB2 expression levels. In paired normal-tumor samples, HOXB2 mRNA and protein levels were significantly reduced in tumors when compared to non-tumor lung tissues. Genetic variants in the HOXB cluster may confer susceptibility to lung cancer by modulating the expression of HOXB2 in the lung.
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http://dx.doi.org/10.1387/ijdb.180210ybDOI Listing
May 2019

Meta-analysis of exome array data identifies six novel genetic loci for lung function.

Wellcome Open Res 2018 12;3. Epub 2018 Jan 12.

Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, NC 27514, USA.

Over 90 regions of the genome have been associated with lung function to date, many of which have also been implicated in chronic obstructive pulmonary disease. We carried out meta-analyses of exome array data and three lung function measures: forced expiratory volume in one second (FEV ), forced vital capacity (FVC) and the ratio of FEV to FVC (FEV /FVC). These analyses by the SpiroMeta and CHARGE consortia included 60,749 individuals of European ancestry from 23 studies, and 7,721 individuals of African Ancestry from 5 studies in the discovery stage, with follow-up in up to 111,556 independent individuals. We identified significant (P<2·8x10 ) associations with six SNPs: a nonsynonymous variant in , which is predicted to be damaging, three intronic SNPs ( and ) and two intergenic SNPs near to and Expression quantitative trait loci analyses found evidence for regulation of gene expression at three signals and implicated several genes, including and . Further interrogation of these loci could provide greater understanding of the determinants of lung function and pulmonary disease.
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http://dx.doi.org/10.12688/wellcomeopenres.12583.3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6081985PMC
January 2018

Identification of susceptibility pathways for the role of chromosome 15q25.1 in modifying lung cancer risk.

Nat Commun 2018 08 13;9(1):3221. Epub 2018 Aug 13.

Clalit National Cancer Control Center, Carmel Medical Center, Haifa, 34361, Israel.

Genome-wide association studies (GWAS) identified the chromosome 15q25.1 locus as a leading susceptibility region for lung cancer. However, the pathogenic pathways, through which susceptibility SNPs within chromosome 15q25.1 affects lung cancer risk, have not been explored. We analyzed three cohorts with GWAS data consisting 42,901 individuals and lung expression quantitative trait loci (eQTL) data on 409 individuals to identify and validate the underlying pathways and to investigate the combined effect of genes from the identified susceptibility pathways. The KEGG neuroactive ligand receptor interaction pathway, two Reactome pathways, and 22 Gene Ontology terms were identified and replicated to be significantly associated with lung cancer risk, with P values less than 0.05 and FDR less than 0.1. Functional annotation of eQTL analysis results showed that the neuroactive ligand receptor interaction pathway and gated channel activity were involved in lung cancer risk. These pathways provide important insights for the etiology of lung cancer.
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http://dx.doi.org/10.1038/s41467-018-05074-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6089967PMC
August 2018

The Overlap of Lung Tissue Transcriptome of Smoke Exposed Mice with Human Smoking and COPD.

Sci Rep 2018 08 8;8(1):11881. Epub 2018 Aug 8.

The University of British Columbia Center for Heart Lung Innovation, St Paul's Hospital, Vancouver, Canada.

Genome-wide mRNA profiling in lung tissue from human and animal models can provide novel insights into the pathogenesis of chronic obstructive pulmonary disease (COPD). While 6 months of smoke exposure are widely used, shorter durations were also reported. The overlap of short term and long-term smoke exposure in mice is currently not well understood, and their representation of the human condition is uncertain. Lung tissue gene expression profiles of six murine smoking experiments (n = 48) were obtained from the Gene Expression Omnibus (GEO) and analyzed to identify the murine smoking signature. The "human smoking" gene signature containing 386 genes was previously published in the lung eQTL study (n = 1,111). A signature of mild COPD containing 7 genes was also identified in the same study. The lung tissue gene signature of "severe COPD" (n = 70) contained 4,071 genes and was previously published. We detected 3,723 differentially expressed genes in the 6 month-exposure mice datasets (FDR <0.1). Of those, 184 genes (representing 48% of human smoking) and 1,003 (representing 27% of human COPD) were shared with the human smoking-related genes and the COPD severity-related genes, respectively. There was 4-fold over-representation of human and murine smoking-related genes (P = 6.7 × 10) and a 1.4 fold in the severe COPD -related genes (P = 2.3 × 10). There was no significant enrichment of the mice and human smoking-related genes in mild COPD signature. These data suggest that murine smoke models are strongly representative of molecular processes of human smoking but less of COPD.
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http://dx.doi.org/10.1038/s41598-018-30313-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6082828PMC
August 2018

Multiethnic meta-analysis identifies ancestry-specific and cross-ancestry loci for pulmonary function.

Nat Commun 2018 07 30;9(1):2976. Epub 2018 Jul 30.

University of California Los Angeles, Los Angeles, CA, 90095, USA.

Nearly 100 loci have been identified for pulmonary function, almost exclusively in studies of European ancestry populations. We extend previous research by meta-analyzing genome-wide association studies of 1000 Genomes imputed variants in relation to pulmonary function in a multiethnic population of 90,715 individuals of European (N = 60,552), African (N = 8429), Asian (N = 9959), and Hispanic/Latino (N = 11,775) ethnicities. We identify over 50 additional loci at genome-wide significance in ancestry-specific or multiethnic meta-analyses. Using recent fine-mapping methods incorporating functional annotation, gene expression, and differences in linkage disequilibrium between ethnicities, we further shed light on potential causal variants and genes at known and newly identified loci. Several of the novel genes encode proteins with predicted or established drug targets, including KCNK2 and CDK12. Our study highlights the utility of multiethnic and integrative genomics approaches to extend existing knowledge of the genetics of lung function and clinical relevance of implicated loci.
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http://dx.doi.org/10.1038/s41467-018-05369-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6065313PMC
July 2018
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