A decade of research on the 17q12-21 asthma locus: Piecing together the puzzle

Asthma-Genomic Advances Toward Risk Prediction

Asthma is a common complex airway disease whose prediction of disease risk and most severe outcomes is crucial in clinical practice for adequate clinical management. This review discusses the latest findings in asthma genomics and current obstacles faced in moving forward to translational medicine. While genome-wide association studies have provided valuable insights into the genetic basis of asthma, there are challenges that must be addressed to improve disease prediction, such as the need for diverse representation, the functional characterization of genetic variants identified, variant selection for genetic testing, and refining prediction models using polygenic risk scores.

Association between polymorphisms on chromosome 17q12-q21 and rhinovirus-induced interferon responses

BACKGROUND

Single nucleotide polymorphisms (SNPs) in genes on chromosome 17q12-q21 are associated with childhood-onset asthma and rhinovirus-induced wheeze. There are few mechanistic data linking chromosome 17q12-q21 to wheezing illness.

OBJECTIVE

We investigated whether 17q12-q21 risk alleles were associated with impaired interferon responses to rhinovirus.

METHODS

In a population-based birth cohort of European ancestry, we stimulated peripheral blood mononuclear cells with rhinovirus A1 (RV-A1) and rhinovirus A16 (RV-A16) and measured IFN and IFN-induced C-X-C motif chemokine ligand 10 (aka IP10) responses in supernatants. We investigated associations between virus-induced cytokines and 6 SNPs in 17q12-q21. Bayesian profile regression was applied to identify clusters of individuals with different immune response profiles and genetic variants.

RESULTS

Five SNPs (in high linkage disequilibrium, r2 ≥ 0.8) were significantly associated with RV-A1-induced IFN-β (rs9303277, P = .010; rs11557467, P = .012; rs2290400, P = .006; rs7216389, P = .008; rs8079416, P = .005). A reduction in RV-A1-induced IFN-β was observed among individuals with asthma risk alleles. There were no significant associations for RV-A1-induced IFN-α or CXCL10, or for any RV-A16-induced IFN/CXCL10. Bayesian profile regression analysis identified 3 clusters that differed in IFN-β induction to RV-A1 (low, medium, high). The typical genetic profile of the cluster associated with low RV-A1-induced IFN-β responses was characterized by a very high probability of being homozygous for the asthma risk allele for all SNPs. Children with persistent wheeze were almost 3 times more likely to be in clusters with reduced/average RV-A1-induced IFN-β responses than in the high immune response cluster.

CONCLUSIONS

Polymorphisms on chromosome 17q12-q21 are associated with rhinovirus-induced IFN-β, suggesting a novel mechanism-impaired IFN-β induction-links 17q12-q21 risk alleles with asthma/wheeze.

Pyroptosis, gasdermins and allergic diseases

Pyroptosis is an inflammatory form of programmed cell death that is distinct from necrosis and apoptosis. Pyroptosis is primarily mediated by the gasdermin family of proteins (GSDMA-E and PVJK), which, when activated by proteolytic cleavage, form pores in the plasma membrane, leading to cell death. While much of the past research on pyroptosis has focused on its role in cancer, metabolic disorders, and infectious diseases, recent experimental and observational studies have begun to implicate pyroptosis in allergic diseases. These studies suggest that gasdermin-mediated pyroptosis contributes to the development of allergic conditions and could offer novel targets for therapy. Here, we review our current understanding of pyroptosis with an emphasis on the role of gasdermins as executioners of pyroptosis and potential mediators to allergic disease. We highlight new discoveries that establish a mechanistic link between the biochemical actions of gasdermins and the onset of allergic diseases. Additionally, we discuss how pyroptosis and gasdermins might contribute to the dysfunction of epithelial barrier, a key factor believed to initiate the progression of various allergic diseases.

PGAP3 regulates human bronchial epithelial cell mRNAs present in asthma and respiratory virus reference data sets

PGAP3 is a glycosylphosphatidylinositol (GPI) phospholipase gene localized within chromosome 17q12-21, a region highly linked to asthma. Although much is known about the function of other chromosome 17q12-21 genes expressed at increased levels in bronchial epithelium such as ORMDL3 and GSDMB, little is known about the function of increased PGAP3 expression in bronchial epithelium in the context of asthma. The aim of this study was therefore to determine whether increased PGAP3 expression in human bronchial epithelial cells regulated expression of mRNA pathways important to the pathogenesis of asthma by utilizing RNA-sequencing and bioinformatic analysis. We performed RNA-sequencing on normal human bronchial epithelial cells transfected with PGAP3 for 24 and 48 hours. PGAP3 regulated genes were compared to asthma and respiratory virus (influenza A, rhinovirus, respiratory syncytial virus) reference data sets to identify PGAP3 target genes and pathways. Approximately 9% of the upregulated PGAP3-induced genes were found in an asthma reference data set, 41% in a rhinovirus reference data set, 33% in an influenza A reference data set, and 3% in a respiratory syncytial virus reference data set. PGAP3 significantly upregulated the expression of several genes associated with the innate immune response and viral signatures of respiratory viruses associated with asthma exacerbations. Two of the highest expressed genes induced by PGAP3 are RSAD2, OASL, and IFN-λ, which are anti-viral genes associated with asthma. PGAP3 also upregulated the antiviral gene BST2, which like PGAP3 is a GPI-anchored protein. We conclude that PGAP3 expression in human bronchial epithelial cells regulates expression of genes known to be linked to asthma, and also regulates the bronchial epithelial expression of genes pertinent to the pathogenesis of respiratory viral triggered asthma exacerbations.

Gasdermin-B (GSDMB) takes center stage in antibacterial defense, inflammatory diseases, and cancer

One of the hottest topics in biomedical research is to decipher the functional implications of the Gasdermin (GSDM) protein family in human pathologies. These proteins are the key effectors of a lytic and pro-inflammatory cell death type termed pyroptosis (also known as "Gasdermin-mediated programmed cell death"). However, ever-growing evidence showed that GSDMs can play multiple and complex roles in a context-dependent manner. In this sense, Gasdermin-B (GSDMB; the only GSDM gene absent in mice and rats) has been implicated in antibacterial defense, numerous inflammatory pathologies (e.g., asthma, ulcerative colitis), and cancer, but both cell death-dependent and -independent functions have been reported in these diseases, fueling the debate on whether GSDMB has genuine pyroptotic capacity. Recently, a series of seminal papers cast light on the GSDMB multitasking capacity by showing that different GSDMB transcriptional isoforms have distinct biological activities. Nonetheless, there are still obscure areas to be clarified on the precise functional involvement of GSDMB translated variants in physiological and pathological conditions. In this viewpoint, we critically discuss the most recent and exciting data on this topic and propose a series of relevant challenges that need to be overcome before GSDMB-driven biomedical applications (as a biomarker of disease risk/progression/outcome or as specific therapeutic target) become a reality in clinical settings.

17q21 Variants Disturb Mucosal Host Defense in Childhood Asthma

Rationale: The strongest genetic risk factor for childhood-onset asthma, the 17q21 locus, is associated with increased viral susceptibility and disease-promoting processes.Objectives: To identify biological targets underlying the escalated viral susceptibility associated with the clinical phenotype mediated by the 17q21 locus.Methods: Genome-wide transcriptome analysis of nasal brush samples from 261 children (78 healthy, 79 with wheezing at preschool age, 104 asthmatic) within the ALLIANCE (All-Age-Asthma) cohort, with a median age of 10.0 (range, 1.0-20.0) years, was conducted to explore the impact of their 17q21 genotype (SNP rs72163891). Concurrently, nasal secretions from the same patients and visits were collected, and high-sensitivity mesoscale technology was employed to measure IFN protein levels.Measurements and Main Results: This study revealed that the 17q21 risk allele induces a genotype- and asthma/wheeze phenotype-dependent enhancement of mucosal GSDMB expression as the only relevant 17q21-encoded gene in children with preschool wheeze. Increased GSDMB expression correlated with the activation of a type-1 proinflammatory, cell-lytic immune, and natural killer signature, encompassing key genes linked to an IFN type-2-signature (IFNG, CXCL9, CXCL10, KLRC1, CD8A, GZMA). Conversely, there was a reduction in IFN type 1 and type 3 expression signatures at the mRNA and protein levels.Conclusions: This study demonstrates a novel disease-driving mechanism induced by the 17q21 risk allele. Increased mucosal GSDMB expression is associated with a cell-lytic immune response coupled with compromised airway immunocompetence. These findings suggest that GSDMB-related airway cell death and perturbations in the mucosal IFN signature account for the increased vulnerability of 17q21 risk allele carriers to respiratory viral infections during early life, opening new options for future biological interventions.The All-Age-Asthma (ALLIANCE) cohort is registered at www.clinicaltrials.gov (pediatric arm, NCT02496468).

Regional variations in allergen-induced airway inflammation correspond to changes in soluble guanylyl cyclase heme and expression of heme oxygenase-1

Asthma is characterized by airway remodeling and hyperreactivity. Our earlier studies determined that the nitric oxide (NO)-soluble guanylyl cyclase (sGC)-cGMP pathway plays a significant role in human lung bronchodilation. However, this bronchodilation is dysfunctional in asthma due to high NO levels, which cause sGC to become heme-free and desensitized to its natural activator, NO. In order to determine how asthma impacts the various lung segments/lobes, we mapped the inflammatory regions of lungs to determine whether such regions coincided with molecular signatures of sGC dysfunction. We demonstrate using murine models of asthma (OVA and CFA/HDM) that the inflamed segments of these murine lungs can be tracked by upregulated expression of HO1 and these regions in turn overlap with regions of heme-free sGC as evidenced by a decreased sGC-α1β1 heterodimer and an increased response to heme-independent sGC activator, BAY 60-2770, relative to naïve uninflamed regions. We also find that NO generated from iNOS upregulation in the inflamed segments has a higher impact on developing heme-free sGC as increasing iNOS activity correlates linearly with elevated heme-independent sGC activation. This excess NO works by affecting the epithelial lung hemoglobin (Hb) to become heme-free in asthma, thereby causing the Hb to lose its NO scavenging function and exposing the underlying smooth muscle sGC to excess NO, which in turn becomes heme-free. Recognition of these specific lung segments enhances our understanding of the inflamed lungs in asthma with the ultimate aim to evaluate potential therapies and suggest that regional and not global inflammation impacts lung function in asthma.

Genetic and T2 biomarkers linked to the efficacy of HDM sublingual immunotherapy in asthma

BACKGROUND

Hypersensitivity to house dust mite (HDM) allergens is a common cause of allergic asthma symptoms and can be effectively treated with allergy immunotherapy (AIT).

OBJECTIVE

To investigate whether genetic and type 2 (T2) inflammatory biomarkers correlate with disease severity in subjects with allergic asthma, and whether this can be modified by AIT.

METHODS

MITRA (NCT01433523) was a phase III, randomised, double-blind, placebo-controlled trial of HDM sublingual immunotherapy (SLIT)-tablets in adults with HDM allergic asthma. Post hoc analyses of the study population (N=742) evaluated associations between T2 inflammatory (blood eosinophils, eosinophil cationic protein (ECP), total IgE and tryptase) and genetic (single-nucleotide polymorphisms, SNP) biomarkers (n=582) for the primary study endpoint (time to first moderate/severe asthma exacerbation). SNP associations were verified in HDM-positive subgroup from an independent 3-year Severe Asthma Research Programme (SARP3) subject cohort.

RESULTS

An increased asthma exacerbation risk in subjects homozygous for SNP rs7216389 (chromosomal locus 17q12-21) was reduced (p=0.037) by treatment with HDM SLIT (HR=0.37 (95% CI 0.22 to 0.64), p<0.001). The associations between exacerbation risk and 17q12-21 SNPs were replicated in the SARP3 HDM-positive subgroup. High levels of T2 biomarkers were associated with increased risk of asthma exacerbations in the placebo group. HDM SLIT-tablet treatment reduced this risk (blood eosinophils: HR=0.50 (95% CI 0.30 to 0.85); ECP: HR=0.45 (95% CI 0.29 to 0.87); tryptase: HR=0.45 (95% CI 0.25 to 0.80)). The treatment effect was higher (p=0.006) for subjects with a higher number of elevated T2 biomarkers.

CONCLUSIONS

HDM SLIT-tablet AIT is efficacious in HDM-sensitised asthma subjects with a genetic asthma predisposition and/or an underlying T2 endotype.

TRIAL REGISTRATION NUMBER

NCT01433523.

The Asthma Risk Gene, GSDMB, Promotes Mitochondrial DNA-induced ISGs Expression

Released mitochondrial DNA (mtDNA) in cells activates cGAS-STING pathway, which induces expression of interferon-stimulated genes (ISGs) and thereby promotes inflammation, as frequently seen in asthmatic airways. However, whether the genetic determinant, Gasdermin B (GSDMB), the most replicated asthma risk gene, regulates this pathway remains unknown. We set out to determine whether and how GSDMB regulates mtDNA-activated cGAS-STING pathway and subsequent ISGs induction in human airway epithelial cells. Using qPCR, ELISA, native polyacrylamide gel electrophoresis, co-immunoprecipitation and immunofluorescence assays, we evaluated the regulation of GSDMB on cGAS-STING pathway in both BEAS-2B cells and primary normal human bronchial epithelial cells (nHBEs). mtDNA was extracted in plasma samples from human asthmatics and the correlation between mtDNA levels and eosinophil counts was analyzed. GSDMB is significantly associated with RANTES expression in asthmatic nasal epithelial brushing samples from the Genes-environments and Admixture in Latino Americans (GALA) II study. Over-expression of GSDMB promotes DNA-induced IFN and ISGs expression in bronchial epithelial BEAS-2B cells and nHBEs. Conversely, knockout of GSDMB led to weakened induction of interferon (IFNs) and ISGs in BEAS-2B cells. Mechanistically, GSDMB interacts with the C-terminus of STING, promoting the translocation of STING to Golgi, leading to the phosphorylation of IRF3 and induction of IFNs and ISGs. mtDNA copy number in serum from asthmatics was significantly correlated with blood eosinophil counts especially in male subjects. GSDMB promotes the activation of mtDNA and poly (dA:dT)-induced activation of cGAS-STING pathway in airway epithelial cells, leading to enhanced induction of ISGs.

Omics approaches in asthma research: Challenges and opportunities

Asthma, a chronic respiratory disease with a global prevalence of approximately 300 million individuals, presents a significant societal and economic burden. This multifaceted syndrome exhibits diverse clinical phenotypes and pathogenic endotypes influenced by various factors. The advent of omics technologies has revolutionized asthma research by delving into the molecular foundation of the disease to unravel its underlying mechanisms. Omics technologies are employed to systematically screen for potential biomarkers, encompassing genes, transcripts, methylation sites, proteins, and even the microbiome components. This review provides an insightful overview of omics applications in asthma research, with a special emphasis on genetics, transcriptomics, epigenomics, and the microbiome. We explore the cutting-edge methods, discoveries, challenges, and potential future directions in the realm of asthma omics research. By integrating multi-omics and non-omics data through advanced statistical techniques, we aspire to advance precision medicine in asthma, guiding diagnosis, risk assessment, and personalized treatment strategies for this heterogeneous condition.

Sphingolipid classes and the interrelationship with pediatric asthma and asthma risk factors

BACKGROUND

While dysregulated sphingolipid metabolism has been associated with risk of childhood asthma, the specific sphingolipid classes and/or mechanisms driving this relationship remain unclear. We aimed to understand the multifaceted role between sphingolipids and other established asthma risk factors that complicate this relationship.

METHODS

We performed targeted LC-MS/MS-based quantification of 77 sphingolipids in plasma from 997 children aged 6 years from two independent cohorts (VDAART and COPSAC2010 ). We examined associations of circulatory sphingolipids with childhood asthma, lung function, and three asthma risk factors: functional SNPs in ORMDL3, low vitamin D levels, and reduced gut microbial maturity. Given racial differences between these cohorts, association analyses were performed separately and then meta-analyzed together.

RESULTS

We observed elevations in circulatory sphingolipids with asthma phenotypes and risk factors; however, there were differential associations of sphingolipid classes with clinical outcomes and/or risk factors. While elevations from metabolites involved in ceramide recycling and catabolic pathways were associated with asthma and worse lung function [meta p-value range: 1.863E-04 to 2.24E-3], increased ceramide levels were associated with asthma risk factors [meta p-value range: 7.75E-5 to .013], but not asthma. Further investigation identified that some ceramides acted as mediators while some interacted with risk factors in the associations with asthma outcomes.

CONCLUSION

This study demonstrates the differential role that sphingolipid subclasses may play in asthma and its risk factors. While overall elevations in sphingolipids appeared to be deleterious overall; elevations in ceramides were uniquely associated with increases in asthma risk factors only; while elevations in asthma phenotypes were associated with recycling sphingolipids. Modification of asthma risk factors may play an important role in regulating sphingolipid homeostasis via ceramides to affect asthma. Further function work may validate the observed associations.

Pyroptosis: a double-edged sword in lung cancer and other respiratory diseases

Pyroptosis is an active cell death process mediated by gasdermin family proteins including Gasdermin A (GSDMA), Gasdermin B (GSDMB), Gasdermin C (GSDMC), Gasdermin D (GSDMD), Gasdermin E (GSDME, DFNA5), and DFNB59. Emerging evidences have shown that pyroptosis contributes to many pulmonary diseases, especially lung cancer, and pneumonia. The exact roles of pyroptosis and gasdermin family proteins are tremendously intricate. Besides, there are evidences that pyroptosis contributes to these respiratory diseases. However, it often plays a dual role in these diseases which is a cause for concern and makes it difficult for clinical translation. This review will focus on the multifaceted roles of pyroptosis in respiratory diseases.

Genetics of preschool wheeze and its progression to childhood asthma

Wheezing is a common and heterogeneous condition in preschool children. In some countries, the prevalence can be as high as 30% and up to 50% of all children experience wheezing before the age of 6. Asthma often starts with preschool wheeze, but not all wheezing children will develop asthma at school age. At this moment, it is not possible to accurately predict which wheezing children will develop asthma. Recently, studying the genetics of wheeze and the childhood-onset of asthma have grown in interest. Childhood-onset asthma has a stronger heritability in comparison with adult-onset asthma. In early childhood asthma exacerbations, CDHR3, which encodes the receptor for Rhinovirus C, was identified, as well as IL33, and the 17q locus that includes GSDMB and ORMDL3 genes. The 17q locus is the strongest wheeze and childhood-onset asthma locus, and was shown to interact with many environmental factors, including smoking and infections. Finally, ANXA1 was recently associated with early-onset, persistent wheeze. ANXA1 may help resolve eosinophilic inflammation. Overall, despite its complexities, genetic approaches to unravel the early-onset of wheeze and asthma are promising, since these shed more light on mechanisms of childhood asthma-onset. Implicated genes point toward airway epithelium and its response to external factors, such as viral infections. However, the heterogeneity of wheeze phenotypes complicates genetic studies. It is therefore important to define accurate wheezing phenotypes and forge larger international collaborations to gain a better understanding of the pathways underlying early-onset asthma.

Association of childhood asthma with Gasdermin B (GSDMB) and Oromucoid-like 3 (ORMDL3) genes

OBJECTIVE

Genome-length association studies have shown that Gasdermin B (GSDMB) and Orosomucoid-like 3 (ORMDL3) genes located on the long arm of chromosome 17 are associated with asthma. In this study, it was aimed to determine the possible relationship between asthma control test (ACT), exercise provocation test (ECT), and fractional nitric oxide (FENO) levels and GSDMB and ORMDL3 gene expressions.

METHODS

59 asthmatic and 38 non-asthmatic children were included in the study. We divided the patient group into two subgroups as mild persistent asthma (29 patients) and moderate persistent asthma (30 patients). ORMDL3, GSDMB gene expression levels, ECT, total IgE levels, and eosinophil counts were measured in all cases. In addition, ACT and FeNO levels were measured in children with asthma. Afterward, the relationship of ORMDL3 and GSDMB gene expression coefficient changes with ECT, ACT, and FeNO was examined.

RESULTS

When patients with ACT ≤15 were compared with patients with ACT ≥20, ORMDL3 and GSDMB gene expressions were increased 6.74 and 11.74 times, respectively. Comparing patients with ACT ≥20 and ACT ≤15 in terms of coefficient changes (ΔCq), higher change values were observed for ΔCq ORMDL3 in patients with ACT ≤15 (p=0.015). Similarly, when patients with FENO ≤25 ppb were compared with patients with FENO >25 ppb, ORMDL3 and GSDMB gene expressions were increased by 2.93 and 3.56 times, respectively. When the coefficient changes were compared, no significant difference was found between FENO≤25 and FENO >25 patients. There was a slight negative correlation between ΔCq values and ACT score (p=0.003, r=-0.418 for ORMDL3, and p=0.016, r=-0.345 for GSDMB). In addition, we observed a statistically significant positive correlation between ORMDL3 and GSDMB gene expressions (r=0.80, p<0.001).

CONCLUSION

We showed that increased ORMDL3 and GSDMB gene expression levels may be associated with ACT scores, FeNO and ECT in asthma. These findings may encourage future studies with larger numbers of subjects that can use gene expression levels in various asthma phenotypes for prognostic prediction.

Sphingolipids in Childhood Asthma and Obesity (SOAP Study): A Protocol of a Cross-Sectional Study

Asthma and obesity are two of the most common chronic conditions in children and adolescents. There is increasing evidence that sphingolipid metabolism is altered in childhood asthma and is linked to airway hyperreactivity. Dysregulated sphingolipid metabolism is also reported in obesity. However, the functional link between sphingolipid metabolism, asthma, and obesity is not completely understood. This paper describes the protocol of an ongoing study on sphingolipids that aims to examine the pathophysiology of sphingolipids in childhood asthma and obesity. In addition, this study aims to explore the novel biomarkers through a comprehensive multi-omics approach including genomics, genome-wide DNA methylation, RNA-Seq, microRNA (miRNA) profiling, lipidomics, metabolomics, and cytokine profiling. This is a cross-sectional study aiming to recruit 440 children from different groups: children with asthma and normal weight (n = 100), asthma with overweight or obesity (n = 100), overweight or obesity (n = 100), normal weight (n = 70), and siblings of asthmatic children with normal weight, overweight, or obesity (n = 70). These participants will be recruited from the pediatric pulmonology, pediatric endocrinology, and general pediatric outpatient clinics at Sidra Medicine, Doha, Qatar. Information will be obtained from self-reported questionnaires on asthma, quality of life, food frequency (FFQ), and a 3-day food diary that are completed by the children and their parents. Clinical measurements will include anthropometry, blood pressure, biochemistry, bioelectrical impedance, and pulmonary function tests. Blood samples will be obtained for sphingolipid analysis, serine palmitoyltransferase (SPT) assay, whole-genome sequencing (WGS), genome-wide DNA methylation study, RNA-Seq, miRNA profiling, metabolomics, lipidomics, and cytokine analysis. Group comparisons of continuous outcome variables will be carried out by a one-way analysis of variance or the Kruskal-Wallis test using an appropriate pairwise multiple comparison test. The chi-squared test or a Fisher's exact test will be used to test the associations between categorical variables. Finally, multivariate analysis will be carried out to integrate the clinical data with multi-omics data. This study will help us to understand the role of dysregulated sphingolipid metabolism in obesity and asthma. In addition, the multi-omics data from the study will help to identify novel genetic and epigenetic signatures, inflammatory markers, and mechanistic pathways that link asthma and obesity in children. Furthermore, the integration of clinical and multi-omics data will help us to uncover the potential interactions between these diseases and to offer a new paradigm for the treatment of pediatric obesity-associated asthma.

Early-immune development in asthma: A review of the literature

This review presents a comprehensive examination of the various factors contributing to the immunopathogenesis of asthma from the prenatal to preschool period. We focus on the contributions of genetic and environmental components as well as the role of the nasal and gut microbiome on immune development. Predisposing genetic factors, including inherited genes associated with increased susceptibility to asthma, are discussed alongside environmental factors such as respiratory viruses and pollutant exposure, which can trigger or exacerbate asthma symptoms. Furthermore, the intricate interplay between the nasal and gut microbiome and the immune system is explored, emphasizing their influence on allergic immune development and response to environmental stimuli. This body of literature underscores the necessity of a comprehensive approach to comprehend and manage asthma, as it emphasizes the interactions of multiple factors in immune development and disease progression.

Association of Asthma Risk Alleles With Acute Respiratory Tract Infections and Wheezing Illnesses in Young Children

BACKGROUND

Genome-wide association studies have identified several risk alleles for early childhood asthma, particularly in the 17q21 locus and in the cadherin-related family member 3 (CDHR3) gene. Contribution of these alleles to the risk of acute respiratory tract infections (ARI) in early childhood is unclear.

METHODS

We analyzed data from the STEPS birth-cohort study of unselected children and the VINKU and VINKU2 studies on children with severe wheezing illness. Genome-wide genotyping was performed on 1011 children. We analyzed the association between 11 preselected asthma risk alleles and the risk of ARIs and wheezing illnesses of various viral etiologies.

RESULTS

The asthma risk alleles in CDHR3, GSDMA, and GSDMB were associated with an increased rate of ARIs (for CDHR3, incidence rate ratio [IRR], 1.06; 95% confidence interval [CI], 1.01-1.12; P = .02), and risk allele in CDHR3 gene with rhinovirus infections (IRR, 1.10; 95% CI, 1.01-1.20, P = .03). Asthma risk alleles in GSDMA, GSDMB, IKZF3, ZPBP2, and ORMDL3 genes were associated with wheezing illnesses in early childhood, especially rhinovirus-positive wheezing illnesses.

CONCLUSIONS

Asthma risk alleles were associated with an increased rate of ARIs and an increased risk of viral wheezing illnesses. Nonwheezing and wheezing ARIs and asthma may have shared genetic risk factors. Clinical Trials Registration. NCT00494624 and NCT00731575.

Structural and functional insights into GSDMB isoforms complex roles in pathogenesis

SHADSGasdermins (GSDMs) have garnered significant scientific interest due to their protective and detrimental roles in innate immunity, host defense, inflammation, and cancer alongside with other pathologies. While GSDMs are mostly recognized as key effectors of a lytic type of pro-inflammatory cell death known as pyroptosis, they do also take part in other cell death processes (NETosis, secondary necrosis, or apoptosis) and exhibit cell-death independent functions depending on the cellular context. Among GSDMs, Gasdermin B (GSDMB) pyroptotic capacity has been a subject of conflicting findings in scientific literature even when its processing, and subsequent activation, by Granzyme A (GZMA) was decoded. Nevertheless, recent groundbreaking publications have shed light on the crucial role of alternative splicing in determining the pyroptotic capacity of GSDMB isoforms, which depends on the presence of exon 6-derived elements. This comprehensive review pays attention to the relevant structural differences among recently crystalized GSDMB isoforms. As a novelty, the structural aspects governing GSDMB isoform susceptibility to GZMA-mediated activation have been investigated. By elucidating the complex roles of GSDMB isoforms, this review aims to deepen the understanding of this multifunctional player and its potential implications in disease pathogenesis and therapeutic interventions. [Figure: see text].

In-silico identification and prioritization of therapeutic targets of asthma

Asthma is a "common chronic disorder that affects the lungs causing variable and recurring symptoms like repeated episodes of wheezing, breathlessness, chest tightness and underlying inflammation. The interaction of these features of asthma determines the clinical manifestations and severity of asthma and the response to treatment" [cited from: National Heart, Lung, and Blood Institute. Expert Panel 3 Report. Guidelines for the Diagnosis and Management of Asthma 2007 (EPR-3). Available at: https://www.ncbi.nlm.nih.gov/books/NBK7232/ (accessed on January 3, 2023)]. As per the WHO, 262 million people were affected by asthma in 2019 that leads to 455,000 deaths ( https://www.who.int/news-room/fact-sheets/detail/asthma ). In this current study, our aim was to evaluate thousands of scientific documents and asthma associated omics datasets to identify the most crucial therapeutic target for experimental validation. We leveraged the proprietary tool Ontosight® Discover to annotate asthma associated genes and proteins. Additionally, we also collected and evaluated asthma related patient datasets through bioinformatics and machine learning based approaches to identify most suitable targets. Identified targets were further evaluated based on the various biological parameters to scrutinize their candidature for the ideal therapeutic target. We identified 7237 molecular targets from published scientific documents, 2932 targets from genomic structured databases and 7690 dysregulated genes from the transcriptomics and 560 targets from genomics mutational analysis. In total, 18,419 targets from all the desperate sources were analyzed and evaluated though our approach to identify most promising targets in asthma. Our study revealed IL-13 as one of the most important targets for asthma with approved drugs on the market currently. TNF, VEGFA and IL-18 were the other top targets identified to be explored for therapeutic benefit in asthma but need further clinical testing. HMOX1, ITGAM, DDX58, SFTPD and ADAM17 were the top novel targets identified for asthma which needs to be validated experimentally.

Contributions of the early-life microbiome to childhood atopy and asthma development

The rapid rise in atopy and asthma in industrialized nations has led to the identification of early life environmental factors that promote these conditions and spurred research into how such exposures may mediate the trajectory to childhood disease development. Over the past decade, the human microbiome has emerged as a key determinant of human health. This is largely due to the increasing appreciation for the myriad of non-mutually exclusive mechanisms by which microbes tune and train host immunity. Microbiomes, particularly those in early life, are shaped by extrinsic and intrinsic factors, including many of the exposures known to influence allergy and asthma risk. This has led to the over-arching hypothesis that such exposures mediate their effect on childhood atopy and asthma by altering the functions and metabolic productivity of microbiomes that shape immune function during this critical developmental period. The capacity to study microbiomes at the genetic and molecular level in humans from the pre-natal period into childhood with well-defined clinical outcomes, offers an unprecedented opportunity to identify early-life and inter-generational determinants of atopy and asthma outcomes. Moreover, such studies provide an integrative microbiome research framework that can be applied to other chronic inflammatory conditions. This review attempts to capture key studies in the field that offer insights into the developmental origins of childhood atopy and asthma, providing novel insights into microbial mediators of maladaptive immunity and chronic inflammatory disease in childhood.

The Long Non-Coding RNA ANRIL in Cancers

ANRIL (Antisense Noncoding RNA in the INK4 Locus), a long non-coding RNA encoded in the human chromosome 9p21 region, is a critical factor for regulating gene expression by interacting with multiple proteins and miRNAs. It has been found to play important roles in various cellular processes, including cell cycle control and proliferation. Dysregulation of ANRIL has been associated with several diseases like cancers and cardiovascular diseases, for instance. Understanding the oncogenic role of ANRIL and its potential as a diagnostic and prognostic biomarker in cancer is crucial. This review provides insights into the regulatory mechanisms and oncogenic significance of the 9p21 locus and ANRIL in cancer.

Global Disease Burden and Attributable Risk Factor Analysis of Asthma in 204 Countries and Territories From 1990 to 2019

PURPOSE

Asthma is a common chronic inflammatory respiratory tract disease with high morbidity and mortality. The global trends in asthma burden remain poorly understood, and asthma incidence has increased during the worldwide coronavirus disease 2019 (COVID-19) pandemic. This study aimed to provide a comprehensive view of the global distribution of asthma burden and its attributable risk factors from 1990 to 2019.

METHODS

Based on the Global Burden of Disease Study 2019 Database, asthma incidence, deaths, disability-adjusted life years (DALYs), the corresponding age-standardized incidence rate (ASIR), age-standardized death rate (ASDR), age-standardized DALY rate, and estimated annual percentage change were analyzed according to age, sex, sociodemographic index (SDI) quintiles, and locations. Risk factors contributing to asthma deaths and DALYs were also investigated.

RESULTS

Globally, the asthma incidence increased by 15%, but deaths and DALYs decreased. The corresponding ASIR, ASDR, and age-standardized DALY rate also decreased. The high SDI region had the highest ASIR, and the low SDI region had the highest ASDR. The ASDR and age-standardized DALY rate were negatively correlated with the SDI. The low-middle SDI region, particularly South Asia, showed the highest asthma-related deaths and DALYs. The incidence peak was under 9 years old, and more than 70% of all deaths occurred in the population over 60 years old. Smoking, occupational asthmagens, and a high body mass index were the main risk factors for asthma-related mortality and DALYs, and their distributions varied between sexes.

CONCLUSIONS

Globally, the asthma incidence has increased since 1990. The greatest asthma burden is borne by the low-middle SDI region. The 2 groups that need special attention are those under 9 years old and those over 60 years old. Targeted strategies are needed to reduce the asthma burden based on geographic and sex-age characteristics. Our findings also provide a platform for further investigation into the asthma burden in the era of COVID-19.

The ERBB2 Exonic Variant Pro1170Ala Modulates Mitogen-Activated Protein Kinase Signaling Cascades and Associates with Allergic Asthma

INTRODUCTION

Previous studies have indicated the ERBB2 genetic variants in the 17q12 locus might be associated with asthma; however, the functional effects of these variants on asthma risk remain inconclusive. This study aimed to characterize the functional roles of asthma-associated ERBB2 single nucleotide polymorphisms (SNPs) in asthma pathogenesis by performing genetic association and functional analysis studies.

METHODS

This study belongs to a part of an ongoing Singapore/Malaysia cross-sectional genetics and epidemiological study (SMCSGES). Genotype-phenotype associations were assessed by performing a genotyping assay on n = 4,348 ethnic Chinese individuals from the SMCSGES cohort. The phosphorylation levels of receptors and signaling proteins in the MAPK signaling cascades, including ErbB2, EGFR, and ERK1/2, were compared across the genotypes of asthma-associated SNPs through in vitro and ex vivo approaches.

RESULTS

The ERBB2 tag-SNP rs1058808 was significantly associated with allergic asthma, with the allele "G" identified as protective against the disease (adjusted logistic p = 6.56 × 10-9, OR = 0.625, 95% CI: 0.544-0.718). The allele "G" of rs1058808 resulted in a Pro1170Ala mutation that results in lower phosphorylation levels of ErbB2 in HaCat cells (p < 0.001), whereas the overall ERBB2 mRNA expression and the phosphorylation levels of EGFR remained unaffected. In the SMCSGES cohort, individuals carrying the genotype "GG" of rs1058808 had lower phosphorylated ERK1/2 proteins in the MAPK signaling cascade. A lower phosphorylation level of ERK1/2 was also associated with reduced asthma risk.

CONCLUSIONS

The present findings highlighted the involvement of a functional exonic variant of ERBB2 in asthma development via modulating the MAPK signaling cascade.

The gasdermin protein family: emerging roles in gastrointestinal health and disease

Since the identification and characterization of gasdermin (GSDM) D as the main effector of inflammatory regulated cell death (or pyroptosis), literature on the GSDM family of pore-forming proteins is rapidly expanding, revealing novel mechanisms regulating their expression and functions that go beyond pyroptosis. Indeed, a growing body of evidence corroborates the importance of GSDMs within the gastrointestinal system, underscoring their critical contributions to the pathophysiology of gastrointestinal cancers, enteric infections and gut mucosal inflammation, such as inflammatory bowel disease. However, with this increase in knowledge, several important and controversial issues have arisen regarding basic GSDM biology and its role(s) during health and disease states. These include critical questions centred around GSDM-dependent lytic versus non-lytic functions, the biological activities of cleaved versus full-length proteins, the differential roles of GSDM-expressing mucosal immune versus epithelial cells, and whether GSDMs promote pathogenic or protective effects during specific disease settings. This Review provides a comprehensive summary and interpretation of the current literature on GSDM biology, specifically focusing on the gastrointestinal tract, highlighting the main controversial issues and their clinical implications, and addressing future areas of research to unravel the specific role(s) of this intriguing, yet enigmatic, family of proteins.

Gasdermins assemble; recent developments in bacteriology and pharmacology

The discovery of gasdermin D (GSDMD) as the terminal executioner of pyroptosis provided a large piece of the cell death puzzle, whilst simultaneously and firmly putting the gasdermin family into the limelight. In its purest form, GSDMD provides a connection between the innate alarm systems to an explosive, inflammatory form of cell death to jolt the local environment into immunological action. However, the gasdermin field has moved rapidly and significantly since the original seminal work and novel functions and mechanisms have been recently uncovered, particularly in response to infection. Gasdermins regulate and are regulated by mechanisms such as autophagy, metabolism and NETosis in fighting pathogen and protecting host. Importantly, activators and interactors of the other gasdermins, not just GSDMD, have been recently elucidated and have opened new avenues for gasdermin-based discovery. Key to this is the development of potent and specific tool molecules, so far a challenge for the field. Here we will cover some of these recently discovered areas in relation to bacterial infection before providing an overview of the pharmacological landscape and the challenges associated with targeting gasdermins.

Regulation of gasdermins in pyroptosis and cytokine release

Gasdermins are effectors of pyroptosis downstream of diverse signaling pathways. Emerging evidence suggests that a number of post-translational modifications regulate the function of gasdermins in pyroptosis, a highly inflammatory form of cell death, and lytic or non-lytic secretion of intracellular contents. These include processing by different caspases and other proteases that may activate or suppress pyroptosis, ubiquitination by a bacterial E3 ligase that suppresses pyroptosis as an immune evasion mechanism, modifications at Cys residues in mammalian or microbial gasdermins that promote or inhibit pyroptosis, and potential phosphorylation that represses pyroptosis. Such diverse regulatory mechanisms by host and microbial proteases, ubiquitin ligases, acyltransferases, kinases and phosphatases may underlie the divergent physiological and pathological functions of gasdermins, and furnish opportunities for therapeutic targeting of gasdermins in infectious diseases and inflammatory disorders.

What Have Mechanistic Studies Taught Us About Childhood Asthma?

Childhood asthma is a chronic heterogeneous syndrome consisting of different disease entities or phenotypes. The immunologic and cellular processes that occur during asthma development are still not fully understood but represent distinct endotypes. Mechanistic studies have examined the role of gene expression, protein levels, and cell types in early life development and the manifestation of asthma, many under the influence of environmental stimuli, which can be both protective and risk factors for asthma. Genetic variants can regulate gene expression, controlled partly by different epigenetic mechanisms. In addition, environmental factors, such as living space, nutrition, and smoking, can contribute to these mechanisms. All of these factors produce modifications in gene expression that can alter the development and function of immune and epithelial cells and subsequently different trajectories of childhood asthma. These early changes in a partially immature immune system can have dramatic effects (e.g., causing dysregulation), which in turn contribute to different disease endotypes and may help to explain differential responsiveness to asthma treatment. In this review, we summarize published studies that have aimed to uncover distinct mechanisms in childhood asthma, considering genetics, epigenetics, and environment. Moreover, a discussion of new, powerful tools for single-cell immunologic assays for phenotypic and functional analysis is included, which promise new mechanistic insights into childhood asthma development and therapeutic and preventive strategies.

Increased expression of ORMDL3 in allergic asthma: a case control and in vitro study

BACKGROUND

Asthma is the most frequent chronic disease in children. One of the most replicated genetic findings in childhood asthma is the ORMDL3 gene confirmed in several GWA studies in several pediatric populations.

OBJECTIVES

The purpose of this study was to analyze ORMDL3 variants and expression in childhood asthma in the Polish population.

METHODS

In the study we included 416 subject, 223 asthmatic children and 193 healthy control subjects. The analysis of two SNPs (rs3744246 and rs8076131) was performed using genotyping with TaqMan probes. The methylation of the ORMDL3 promoter was examined with Methylation Sensitive HRM (MS-HRM), covering 9 CpG sites. The expression of ORMDL3 was analyzed in PBMCs from pediatric patients diagnosed with allergic asthma and primary human bronchial epithelial cells derived from healthy subjects treated with IL-13, IL-4, or co-treatment with both cytokines to model allergic airway inflammation.

RESULTS

We found that ORMDL3 expression was increased in allergic asthma both in PBMCs from asthmatic patients as well as in human bronchial epithelial cells stimulated with the current cytokines. We did not observe significant differences between cases and controls either in the genotype distribution of analyzed SNPs (rs3744246 and rs8076131) nor in the level of promoter methylation.

CONCLUSIONS

Increased ORMDL3 expression is associated with pediatric allergic asthma and upregulated in the airways upon Th2-cytokines stimulation, but further functional studies are required to fully understand its role in this disease.

Genome-wide DNA methylation profiling after Ayurveda intervention to bronchial asthmatics identifies differential methylation in several transcription factors with immune process related function

BACKGROUND

The Indian traditional medicinal system, Ayurveda, describes several lifestyle practices, processes and medicines as an intervention to treat asthma. Rasayana therapy is one of them and although these treatment modules show improvement in bronchial asthma, their mechanism of action, particularly the effect on DNA methylation, is largely understudied.

OBJECTIVES

Our study aimed at identifying the contribution of DNA methylation changes in modulating bronchial asthma phenotype upon Ayurveda intervention.

MATERIALS AND METHODS

In this study, genome-wide methylation profiling in peripheral blood DNA of healthy controls and bronchial asthmatics before (BT) and after (AT) Ayurveda treatment was performed using array-based profiling of reference-independent methylation status (aPRIMES) coupled to microarray technique.

RESULTS

We identified 4820 treatment-associated DNA methylation signatures (TADS) and 11,643 asthma-associated DNA methylation signatures (AADS), differentially methylated [FDR (≤0.1) adjusted p-values] in AT and HC groups respectively, compared to BT group. Neurotrophin TRK receptor signaling pathway was significantly enriched for differentially methylated genes in bronchial asthmatics, compared to AT and HC subjects. Additionally, we identified over 100 differentially methylated immune-related genes located in the promoter/5'-UTR regions of TADS and AADS. Various immediate-early response and immune regulatory genes with functions such as transcription factor activity (FOXD1, FOXD2, GATA6, HOXA3, HOXA5, MZF1, NFATC1, NKX2-2, NKX2-3, RUNX1, KLF11), G-protein coupled receptor activity (CXCR4, PTGER4), G-protein coupled receptor binding (UCN), DNA binding (JARID2, EBF2, SOX9), SNARE binding (CAPN10), transmembrane signaling receptor activity (GP1BB), integrin binding (ITGA6), calcium ion binding (PCDHGA12), actin binding (TRPM7, PANX1, TPM1), receptor tyrosine kinase binding (PIK3R2), receptor activity (GDNF), histone methyltransferase activity (MLL5), and catalytic activity (TSTA3) were found to show consistent methylation status between AT and HC group in microarray data.

CONCLUSIONS

Our study reports the DNA methylation-regulated genes in bronchial asthmatics showing improvement in symptoms after Ayurveda intervention. DNA methylation regulation in the identified genes and pathways represents the Ayurveda intervention responsive genes and may be further explored as diagnostic, prognostic, and therapeutic biomarkers for bronchial asthma in peripheral blood.

Decoding the genetic and epigenetic basis of asthma

Asthma is a complex and heterogeneous chronic inflammatory disease of the airways. Alongside environmental factors, asthma susceptibility is strongly influenced by genetics. Given its high prevalence and our incomplete understanding of the mechanisms underlying disease susceptibility, asthma is frequently studied in genome-wide association studies (GWAS), which have identified thousands of genetic variants associated with asthma development. Virtually all these genetic variants reside in non-coding genomic regions, which has obscured the functional impact of asthma-associated variants and their translation into disease-relevant mechanisms. Recent advances in genomics technology and epigenetics now offer methods to link genetic variants to gene regulatory elements embedded within non-coding regions, which have started to unravel the molecular mechanisms underlying the complex (epi)genetics of asthma. Here, we provide an integrated overview of (epi)genetic variants associated with asthma, focusing on efforts to link these disease associations to biological insight into asthma pathophysiology using state-of-the-art genomics methodology. Finally, we provide a perspective as to how decoding the genetic and epigenetic basis of asthma has the potential to transform clinical management of asthma and to predict the risk of asthma development.

Dog ownership in infancy is protective for persistent wheeze in 17q21 asthma-risk carriers

BACKGROUND

Asthma-associated single nucleotide polymorphisms from large genome-wide association studies only explain a fraction of genetic heritability. Likely causes of the missing heritability include broad phenotype definitions and gene-environment interactions (GxE). The mechanisms underlying GxE in asthma are poorly understood. Previous GxE studies on pet ownership showed discordant results.

OBJECTIVES

We sought to study the GxE between the 17q12-21 locus and pet ownership in infancy in relation to wheeze.

METHODS

Wheezing classes derived from 5 UK-based birth cohorts (latent class analysis) were used to study GxE between the 17q12-21 asthma-risk variant rs2305480 and dog and cat ownership in infancy, using multinomial logistic regression. A total of 9149 children had both pet ownership and genotype data available. Summary statistics from individual analyses were meta-analyzed.

RESULTS

rs2305480 G allele was associated with increased risk of persistent wheeze (additive model odds ratio, 1.37; 95% CI, 1.25-1.51). There was no evidence of an association between dog or cat ownership and wheeze. We found significant evidence of a GxE interaction between rs2305480 and dog ownership (P = 8.3 × 10-4) on persistent wheeze; among dog owners, the G allele was no longer associated with an increased risk of persistent wheeze (additive model odds ratio, 0.95; 95% CI, 0.73-1.24). For those without pets, G allele was associated with increased risk of persistent wheeze (odds ratio, 1.61; 95% CI, 1.40-1.86). Among cat owners, no such dampening of the genetic effect was observed.

CONCLUSIONS

Among dog owners, rs2305480 G was no longer associated with an increased risk of persistent wheeze (or asthma). Early-life environmental exposures may therefore attenuate likelihood of asthma in those carrying 17q12-21 risk alleles.

FGF20 and PGM2 variants are associated with childhood asthma in family-based whole-genome sequencing studies

BACKGROUND

Asthma is a heterogeneous common respiratory disease that remains poorly understood. The established genetic associations fail to explain the high estimated heritability, and the prevalence of asthma differs between populations and geographic regions. Robust association analyses incorporating different genetic ancestries and whole-genome sequencing data may identify novel genetic associations.

METHODS

We performed family-based genome-wide association analyses of childhood-onset asthma based on whole-genome sequencing (WGS) data for the 'The Genetic Epidemiology of Asthma in Costa Rica' study (GACRS) and the Childhood Asthma Management Program (CAMP). Based on parent-child trios with children diagnosed with asthma, we performed a single variant analysis using an additive and a recessive genetic model and a region-based association analysis of low-frequency and rare variants.

RESULTS

Based on 1180 asthmatic trios (894 GACRS trios and 286 CAMP trios, a total of 3540 samples with WGS data), we identified three novel genetic loci associated with childhood-onset asthma: rs4832738 on 4p14 ($P=1.72\ast{10}^{-9}$, recessive model), rs1581479 on 8p22 ($P=1.47\ast{10}^{-8}$, additive model) and rs73367537 on 10q26 ($P=1.21\ast{10}^{-8}$, additive model in GACRS only). Integrative analyses suggested potential novel candidate genes underlying these associations: PGM2 on 4p14 and FGF20 on 8p22.

CONCLUSION

Our family-based whole-genome sequencing analysis identified three novel genetic loci for childhood-onset asthma. Gene expression data and integrative analyses point to PGM2 on 4p14 and FGF20 on 8p22 as linked genes. Furthermore, region-based analyses suggest independent potential low-frequency/rare variant associations on 8p22. Follow-up analyses are needed to understand the functional mechanisms and generalizability of these associations.

Genetic Variants Associated with Bronchial Asthma Specific to the Population of the Russian Federation

Bronchial asthma (BA) is a disease that still lacks an exhaustive treatment protocol. In this regard, the global medical community pays special attention to the genetic prerequisites for the occurrence of this disease. Therefore, the search for the genetic polymorphisms underlying bronchial asthma has expanded considerably. As the present study progressed, a significant amount of scientific medical literature was analyzed and 167 genes reported to be associated with the development of bronchial asthma were identified. A group of participants (n = 7,303) who had voluntarily provided their biomaterial (venous blood) to be used in the research conducted by the Federal Medical Biological Agency of Russia was formed to subsequently perform a bioinformatic verification of known associations and search for new ones. This group of participants was divided into four cohorts, including two sex-distinct cohorts of individuals with a history of asthma and two sex-distinct cohorts of apparently healthy individuals. A search for polymorphisms was made in each cohort among the selected genes, and genetic variants were identified whose difference in occurrence in the different cohorts was statistically significant (significance level less than 0.0001). The study revealed 11 polymorphisms that affect the development of asthma: four genetic variants (rs869106717, rs1461555098, rs189649077, and rs1199362453), which are more common in men with bronchial asthma compared to apparently healthy men; five genetic variants (rs1923038536, rs181066119, rs143247175, rs140597386, and rs762042586), which are more common in women with bronchial asthma compared to apparently healthy women; and two genetic variants (rs1219244986 and rs2291651) that are rare in women with a history of asthma.

The Association of Prenatal C-Reactive Protein Levels With Childhood Asthma and Atopy

BACKGROUND

The pathogenesis of childhood asthma is complex, and determinants of risk may begin in utero.

OBJECTIVE

To describe the association of systemic prenatal inflammation, measured by plasma C-reactive protein (CRP), with childhood asthma, eczema, and allergic rhinitis.

METHODS

A total of 522 maternal-offspring pairs from the Vitamin D Antenatal Asthma Reduction Trial were included. Prenatal plasma CRP level was measured between 10 and 18 weeks of gestation and between 32 and 38 weeks of gestation. Offspring asthma, eczema, and allergic rhinitis were assessed quarterly between birth and age 6 years. We performed mediation analyses of prenatal CRP on the association between several maternal characteristics and offspring asthma.

RESULTS

Elevated early and late prenatal CRP and an increase in CRP from early to late pregnancy were associated with asthma by age 6 years (early: adjusted odds ratio [aOR], 1.76, 95% CI, 1.12-2.82, P = .02; late: aOR, 2.45, 95% CI, 1.47-4.18, P < .001; CRP increase: aOR, 2.06, 95% CI, 1.26-3.39, P < .004). Prenatal CRP and childhood asthma associations were strengthened among offspring with atopic asthma (early: aOR, 3.78, 95% CI, 1.49-10.64, P = .008; late: aOR, 4.84, 95% CI, 1.68-15.50, P = .005; CRP increase: aOR, 3.01, 95% CI, 1.06-9.16, P = .04). Early and late prenatal CRP mediated 96% and 86% of the association between maternal prepregnancy body mass index and offspring asthma, respectively.

CONCLUSIONS

Higher prenatal CRP and an increase in CRP from early to late pregnancy are associated with childhood asthma. Systemic inflammation during pregnancy associated with modifiable maternal characteristics may be an important determinant of childhood asthma risk.

GSDM gene polymorphisms regulate the IgE level in asthmatic patients

Background

Gasdermin A (GSDMA) and gasdermin B (GSDMB) have been associated with childhood and adult asthma in many populations including the Jordanian population. It is also known that IgE plays a crucial role in various allergic disorders, such elevated levels of total serum IgE were detected in asthma and allergic rhinitis. IgE immunoglobulin is responsible for the release of numerous inflammatory mediators, such as histamine and prostaglandins, from mast cells in asthmatic patients.

Objective

In this study, single nucleotide polymorphisms of GSDMA (rs7212938, T/G) and GSDMB (rs7216389, T/C) in Jordanian population were investigated for their association with total IgE levels in serum of asthmatic children and adult subjects.

Methods

The genetic polymorphism analysis for SNPs was performed using the polymerase chain reaction (PCR)/restriction fragment length polymorphism method (RFLP). Three analysis models were applied to the genotype data: co-dominant, dominant and recessive.

Results

Our data demonstrate a significant correlation between GSDMB genetic SNP (rs7216389) and the total IgE serum level. Where one minor allele in the GSDMB gene is sufficient to induce significant changes in the IgE serum levels and plays a role in the pathogenesis of asthma in asthmatic children of the Jordanian population. Suggesting that this polymorphism might have a protective effect against asthma risk. While the presence of the GSDMB polymorphism alone might not be sufficient to associate with the high risk of developing asthma or responding to it in adults in Jordanian population.

Conclusion

In conclusion, the current study confirms the significant association of GSDMB genetic SNP (rs7216389) with IgE levels in asthma patients in Jordanian population, while no significant correlation of GSDMA and IgE level was found in both child and adult asthmatic patients.

New Insights Relating Gasdermin B to the Onset of Childhood Asthma

Chromosome 17q12-q21 is the most replicated genetic locus for childhood-onset asthma. Polymorphisms in this locus containing ∼10 genes interact with a variety of environmental exposures in the home and outdoors to modify asthma risk. However, the functional basis for these associations and their linkages to the environment have remained enigmatic. Within this extended region, regulation of GSDMB (gasdermin B) expression in airway epithelial cells has emerged as the primary mechanism underlying the 17q12-q21 genome-wide association study signal. Asthma-associated SNPs influence the abundance of GSDMB transcripts as well as the functional properties of GSDMB protein in airway epithelial cells. GSDMB is a member of the gasdermin family of proteins, which regulate pyroptosis and inflammatory responses to microbial infections. The aims of this review are to synthesize recent studies on the relationship of 17q12-q21 SNPs to childhood asthma and the evidence pointing to GSDMB gene expression or protein function as the underlying mechanism and to explore the potential functions of GSDMB that may influence the risk of developing asthma during childhood.

African-specific alleles modify risk for asthma at the 17q12-q21 locus in African Americans

BACKGROUND

Asthma is the most common chronic disease in children, occurring at higher frequencies and with more severe disease in children with African ancestry.

METHODS

We tested for association with haplotypes at the most replicated and significant childhood-onset asthma locus at 17q12-q21 and asthma in European American and African American children. Following this, we used whole-genome sequencing data from 1060 African American and 100 European American individuals to identify novel variants on a high-risk African American-specific haplotype. We characterized these variants in silico using gene expression and ATAC-seq data from airway epithelial cells, functional annotations from ENCODE, and promoter capture (pc)Hi-C maps in airway epithelial cells. Candidate causal variants were then assessed for correlation with asthma-associated phenotypes in African American children and adults.

RESULTS

Our studies revealed nine novel African-specific common variants, enriched on a high-risk asthma haplotype, which regulated the expression of GSDMA in airway epithelial cells and were associated with features of severe asthma. Using ENCODE annotations, ATAC-seq, and pcHi-C, we narrowed the associations to two candidate causal variants that are associated with features of T2 low severe asthma.

CONCLUSIONS

Previously unknown genetic variation at the 17q12-21 childhood-onset asthma locus contributes to asthma severity in individuals with African ancestries. We suggest that many other population-specific variants that have not been discovered in GWAS contribute to the genetic risk for asthma and other common diseases.

Genome-wide study of early and severe childhood asthma identifies interaction between CDHR3 and GSDMB

BACKGROUND

Asthma with severe exacerbation is one of the most common causes of hospitalization among young children. Exacerbations are typically triggered by respiratory infections, but the host factors causing recurrent infections and exacerbations in some children are poorly understood. As a result, current treatment options and preventive measures are inadequate.

OBJECTIVE

We sought to identify genetic interaction associated with the development of childhood asthma.

METHODS

We performed an exhaustive search for pairwise interaction between genetic single nucleotide polymorphisms using 1204 cases of a specific phenotype of early childhood asthma with severe exacerbations in patients aged 2 to 6 years combined with 5328 nonasthmatic controls. Replication was attempted in 3 independent populations, and potential underlying immune mechanisms were investigated in the COPSAC2010 and COPSAC2000 birth cohorts.

RESULTS

We found evidence of interaction, including replication in independent populations, between the known childhood asthma loci CDHR3 and GSDMB. The effect of CDHR3 was dependent on the GSDMB genotype, and this interaction was more pronounced for severe and early onset of disease. Blood immune analyses suggested a mechanism related to increased IL-17A production after viral stimulation.

CONCLUSIONS

We found evidence of interaction between CDHR3 and GSDMB in development of early childhood asthma, possibly related to increased IL-17A response to viral infections. This study demonstrates the importance of focusing on specific disease subtypes for understanding the genetic mechanisms of asthma.

Translational Analysis of Moderate to Severe Asthma GWAS Signals Into Candidate Causal Genes and Their Functional, Tissue-Dependent and Disease-Related Associations

Asthma affects more than 300 million people globally and is both under diagnosed and under treated. The most recent and largest genome-wide association study investigating moderate to severe asthma to date was carried out in 2019 and identified 25 independent signals. However, as new and in-depth downstream databases become available, the translational analysis of these signals into target genes and pathways is timely. In this study, unique (U-BIOPRED) and publicly available datasets (HaploReg, Open Target Genetics and GTEx) were investigated for the 25 GWAS signals to identify 37 candidate causal genes. Additional traits associated with these signals were identified through PheWAS using the UK Biobank resource, with asthma and eosinophilic traits amongst the strongest associated. Gene expression omnibus dataset examination identified 13 candidate genes with altered expression profiles in the airways and blood of asthmatic subjects, including MUC5AC and STAT6. Gene expression analysis through publicly available datasets highlighted lung tissue cell specific expression, with both MUC5AC and SLC22A4 genes showing enriched expression in ciliated cells. Gene enrichment pathway and interaction analysis highlighted the dominance of the HLA-DQA1/A2/B1/B2 gene cluster across many immunological diseases including asthma, type I diabetes, and rheumatoid arthritis. Interaction and prediction analyses found IL33 and IL18R1 to be key co-localization partners for other genes, predicted that CD274 forms co-expression relationships with 13 other genes, including the HLA-DQA1/A2/B1/B2 gene cluster and that MUC5AC and IL37 are co-expressed. Drug interaction analysis revealed that 11 of the candidate genes have an interaction with available therapeutics. This study provides significant insight into these GWAS signals in the context of cell expression, function, and disease relationship with the view of informing future research and drug development efforts for moderate-severe asthma.

Time-Specific Factors Influencing the Development of Asthma in Children

Susceptibility to asthma is complex and heterogeneous, as it involves both genetic and environmental insults (pre- and post-birth) acting in a critical window of development in early life. According to the Developmental Origins of Health and Disease, several factors, both harmful and protective, such as nutrition, diseases, drugs, microbiome, and stressors, interact with genotypic variation to change the capacity of the organism to successfully adapt and grow in later life. In this review, we aim to provide the latest evidence about predictive risk and protective factors for developing asthma in different stages of life, from the fetal period to adolescence, in order to develop strategic preventive and therapeutic interventions to predict and improve health later in life. Our study shows that for some risk factors, such as exposure to cigarette smoke, environmental pollutants, and family history of asthma, the evidence in favor of a strong association of those factors with the development of asthma is solid and widely shared. Similarly, the clear benefits of some protective factors were shown, providing new insights into primary prevention. On the contrary, further longitudinal studies are required, as some points in the literature remain controversial and a source of debate.

17q12-21 risk-variants influence cord blood immune regulation and multitrigger-wheeze

BACKGROUND

Childhood wheeze represents a first symptom of asthma. Early identification of children at risk for wheeze related to 17q12-21 variants and their underlying immunological mechanisms remain unknown. We aimed to assess the influence of 17q12-21 variants and mRNA expression at birth on the development of wheeze.

METHODS

Children were classified as multitrigger/viral/no wheeze until six years of age. The PAULINA/PAULCHEN birth cohorts were genotyped (n = 216; GSA-chip). mRNA expression of 17q21 and innate/adaptive genes was measured (qRT-PCR) in cord blood mononuclear cells. Expression quantitative trait loci (eQTL) and mediation analyses were performed. Genetic variation of 17q12-21 asthma-single nucleotide polymorphisms (SNPs) was summarized as the first principal component (PC1) and used to classify single SNP effects on gene expression as (locus)-dependent/independent eQTL SNPs.

RESULTS

Core region risk variants (IKZF3, ZPBP2, GSDMB, ORMDL3) were associated with multitrigger wheeze (OR: 3.05-5.43) and were locus-dependent eQTL SNPs with higher GSDMA, TLR2, TLR5, and lower TGFB1 expression. Increased risk of multitrigger wheeze with rs9303277 was in part mediated by TLR2 expression. Risk variants distal to the core region were mainly locus-independent eQTL SNPs with decreased CD209, CD86, TRAF6, RORA, and IL-9 expression. Distinct immune signatures in cord blood were associated either with multitrigger wheeze (increased innate genes, e.g., TLR2, IPS1, LY75) or viral wheeze (decreased NF-κB genes, e.g., TNFAIP3 and TNIP2).

CONCLUSION

Locus-dependent eQTL SNPs (core region) associated with increased inflammatory genes (primarily TLR2) at birth and subsequent multitrigger wheeze indicate that early priming and imbalance may be crucial for asthma pathophysiology. Locus-independent eQTL SNPs (mainly distal region, rs1007654) may be involved in the initiation of dendritic cell activation/maturation (TRAF6) and interaction with T cells (CD209, CD86). Identifying potential mechanistic pathways at birth may point to critical key points during early immune development predisposing to asthma.

Prenatal tobacco exposure and risk of asthma and allergy outcomes in childhood

BACKGROUND

Harmful effects of prenatal tobacco exposure and possible interaction with 17q12-21 genetic variants have been shown for some asthma outcomes in childhood, whereas findings related to allergy outcomes are more inconsistent. This study aimed to examine the effect of prenatal tobacco exposure and relation to 17q12-21 genotype on a wide array of asthma and allergy-related outcomes in early childhood.

METHODS

Prenatal tobacco exposure was determined by maternal smoking during the third trimester (yes/no) in 411 children from the phenotyped Copenhagen Prospective Studies on Asthma in Childhood 2000 (COPSAC2000) birth cohort with clinical follow-up to age 7 years. The rs7216389 single nucleotide polymorphism was used as main representative of the 17q12-21 locus. Asthma end-points included asthma diagnosis, exacerbations, episodes with troublesome lung symptoms and lower respiratory tract infections, spirometry, plethysmography, bronchial responsiveness to methacholine, exercise and cold dry air. Allergy-related endpoints included aeroallergen sensitisation, allergic rhinitis, fractional exhaled nitric oxide, blood eosinophil count and urine eosinophil protein X levels. Statistical analyses were done using Cox regression, linear regression, logistic regression and quasi-Poisson regression.

RESULTS

Prenatal tobacco exposure increased the risk of asthma (adjusted hazard ratio (aHR) 2.05, 95% CI 1.13-3.73; p=0.02), exacerbations (aHR 3.76, 95% CI 2.05-6.91; p<0.001), number of LRTIs (adjusted incidence rate ratio 1.87, 95% CI 1.34-2.55; p<0.001), and was associated with decreased spirometry indices (forced expiratory volume in 1 s (FEV1) adjusted mean difference (aMD) -0.07 L, 95% CI -0.13- -0.005 L, p=0.03; maximal mid-expiratory flow aMD -0.19 L·s-1, -0.34- -0.04 L·s-1, p=0.01) and increased bronchial responsiveness to methacholine (provocative dose of methacholine causing a 20% drop in FEV1 adjusted geometric mean ratio 0.55, 95% CI 0.31-0.96; p=0.04). In contrast, there was no association with any allergy-related end-points. The effect on asthma depended on 17q12-21 genotype with an increased risk only among children without risk alleles.

CONCLUSION

Prenatal tobacco exposure was associated with asthma dependent on 17q12-21 genotype and with exacerbations, lung function and bronchial responsiveness, but not with any allergy-related outcomes. This suggests that tobacco exposure in utero leads to adverse lung developmental/structural effects rather than susceptibility to develop allergy and type 2 inflammation.

GSDMB is increased in IBD and regulates epithelial restitution/repair independent of pyroptosis

Gasdermins are a family of structurally related proteins originally described for their role in pyroptosis. Gasdermin B (GSDMB) is currently the least studied, and while its association with genetic susceptibility to chronic mucosal inflammatory disorders is well established, little is known about its functional relevance during active disease states. Herein, we report increased GSDMB in inflammatory bowel disease, with single-cell analysis identifying epithelial specificity to inflamed colonocytes/crypt top colonocytes. Surprisingly, mechanistic experiments and transcriptome profiling reveal lack of inherent GSDMB-dependent pyroptosis in activated epithelial cells and organoids but instead point to increased proliferation and migration during in vitro wound closure, which arrests in GSDMB-deficient cells that display hyper-adhesiveness and enhanced formation of vinculin-based focal adhesions dependent on PDGF-A-mediated FAK phosphorylation. Importantly, carriage of disease-associated GSDMB SNPs confers functional defects, disrupting epithelial restitution/repair, which, altogether, establishes GSDMB as a critical factor for restoration of epithelial barrier function and the resolution of inflammation.

Multi-Omics Profiling Approach to Asthma: An Evolving Paradigm

Asthma is a complex multifactorial and heterogeneous respiratory disease. Although genetics is a strong risk factor of asthma, external and internal exposures and their interactions with genetic factors also play important roles in the pathophysiology of asthma. Over the past decades, the application of high-throughput omics approaches has emerged and been applied to the field of asthma research for screening biomarkers such as genes, transcript, proteins, and metabolites in an unbiased fashion. Leveraging large-scale studies representative of diverse population-based omics data and integrating with clinical data has led to better profiling of asthma risk. Yet, to date, no omic-driven endotypes have been translated into clinical practice and management of asthma. In this article, we provide an overview of the current status of omics studies of asthma, namely, genomics, transcriptomics, epigenomics, proteomics, exposomics, and metabolomics. The current development of the multi-omics integrations of asthma is also briefly discussed. Biomarker discovery following multi-omics profiling could be challenging but useful for better disease phenotyping and endotyping that can translate into advances in asthma management and clinical care, ultimately leading to successful precision medicine approaches.

Genome-wide association study identifies TNFSF15 associated with childhood asthma

BACKGROUND

Genome-wide association studies (GWASs) of asthma have identified several risk alleles and loci, but most have been conducted in individuals with European-ancestry. Studies in Asians, especially children, are still lacking. We aimed to identify susceptibility loci by performing the first GWAS of asthma in Korean children with persistent asthma.

METHODS

We used a discovery set of 741 children with persistent asthma as cases and 589 healthy children and 551 healthy adults as controls to perform a GWAS. We validated our GWAS findings using UK Biobank data. We then used the Genotype-Tissue Expression database to identify expression quantitative trait loci of candidate variants. Finally, we quantified proteins of genes associated with asthma.

RESULTS

Variants at the 17q12-21 locus and SNPs in CYBRD1 and TNFSF15 genes were associated with persistent childhood asthma at genome-wide thresholds of significance. Four SNPs in the TNFSF15 gene were also associated with childhood-onset asthma in British white participants in the UK Biobank data. The asthma-associated rs7856856-C allele, the lead SNP, was associated with decreased TNFSF15 expression in whole blood and in arteries. Korean children with asthma had lower serum TNFSF15 levels than controls, and those with the asthma risk rs7856856-CC genotype exhibited the lowest serum TNFSF15 levels overall, especially asthmatic children.

CONCLUSIONS

Our GWAS of persistent childhood asthma with allergic sensitization identified a new susceptibility gene, TNFSF15, and replicated associations at the 17q12-21 childhood-onset asthma locus. This novel association may be mediated by reduced expression of serum TNFSF15 and loss of suppression of angiogenesis.