Identification of ATPAF1 as a novel candidate gene for asthma in children

Investigation of the shared biological mechanisms and common biomarker APTAF1 of sleep deprivation and mild cognitive impairment using integrated bioinformatics analysis

Introduction: The relationship between sleep loss and cognitive impairment has long been widely recognized, but there is still a lack of complete understanding of the underlying mechanisms and potential biomarkers. The purpose of this study is to further explore the shared biological mechanisms and common biomarkers between sleep loss and cognitive impairment. Methods: The mitochondria-related genes and gene expression data were downloaded from the MitoCarta3.0 and Gene Expression Omnibus (GEO) databases. We identified the differentially expressed mitochondrial-related genes by combing the differentially expressed genes (DEGs) in sleep deprivation (SD) and mild cognitive impairment (MCI) datasets with mitochondria-related gene lists. Shared DEGs were then further analyzed for enrichment analysis. Next, the common biomarker was identified using two machine learning techniques and further validated using two independent GEO datasets. Then GSEA and GSVA were conducted to analyze the functional categories and pathways enriched for the common biomarker. Finally, immune infiltration analysis was used to investigate the correlation of immune cell infiltration with the common biomarker in SD and MCI. Results: A total of 32 mitochondrial-related differentially expressed genes were identified in SD and MCI. GO analysis indicated that these genes were significantly enriched for mitochondrial transport, and KEGG analysis showed they were mainly involved in pathways of neurodegenerative diseases. In addition, ATPAF1, which was significantly down-regulated in both SD and MCI, was identified through machine learning algorithms as the common biomarker with favorable diagnostic performance. GSEA and GSVA revealed that ATPAF1 was mainly involved in metabolic pathways, such as oxidative phosphorylation, acetylcholine metabolic process, valine, leucine and isoleucine degradation. Immune infiltration analysis showed that the expression of ATPAF1 was correlated with changes in immune cells, especially those key immune cell types associated with SD and MCI. Discussion: This study firstly revealed that mitochondrial dysfunction may be the common pathogenesis of sleep loss and mild cognitive impairment and identified ATPAF1 as a possible biomarker and therapeutic target involved in SD and MCI.

LINC00115 promotes gastric cancer partly by the miR-212-5p/ATPAF1 axis

LncRNAs are known to be key regulators in the initiation and development of diverse cancers. Whether LINC00115 is involved in the regulation of gastric cancer (GC) progression remains unclear. Here, we aimed to show the function of LINC00115 in GC. RT-qPCR was used to measure gene expression in GC tissues and cells. Colony formation, EdU, TUNEL, and wound healing assays were used to analyze cellular processes in GC. The in vivo GC xenograft model was established. We observed that LINC00115 was highly expressed in GC. Functionally, silencing LINC00115 inhibited GC cell proliferation, and migration but facilitated GC apoptosis. Mechanistically, LINC00115 sponged miR-212-5p, while miR-212-5p targeted ATPAF1 in GC cells. Rescue assays showed ATPAF1 overexpression countervailed the inhibitory role of LINC00115 depletion in GC progression in vitro and in vivo. Overall, LINC00115 promoted GC progression by upregulating ATPAF1 via miR-212-5p.

In fission yeast, 65 non-essential mitochondrial proteins related to respiration and stress become essential in low-glucose conditions

Mitochondria perform critical functions, including respiration, ATP production, small molecule metabolism, and anti-oxidation, and they are involved in a number of human diseases. While the mitochondrial genome contains a small number of protein-coding genes, the vast majority of mitochondrial proteins are encoded by nuclear genes. In fission yeast Schizosaccharomyces pombe, we screened 457 deletion (del) mutants deficient in nuclear-encoded mitochondrial proteins, searching for those that fail to form colonies in culture medium containing low glucose (0.03-0.1%; low-glucose sensitive, lgs), but that proliferate in regular 2-3% glucose medium. Sixty-five (14%) of the 457 deletion mutants displayed the lgs phenotype. Thirty-three of them are defective either in dehydrogenases, subunits of respiratory complexes, the citric acid cycle, or in one of the nine steps of the CoQ10 biosynthetic pathway. The remaining 32 lgs mutants do not seem to be directly related to respiration. Fifteen are implicated in translation, and six encode transporters. The remaining 11 function in anti-oxidation, amino acid synthesis, repair of DNA damage, microtubule cytoskeleton, intracellular mitochondrial distribution or unknown functions. These 32 diverse lgs genes collectively maintain mitochondrial functions under low (1/20-1/60× normal) glucose concentrations. Interestingly, 30 of them have homologues associated with human diseases.

Pathogenesis of allergic diseases and implications for therapeutic interventions

Allergic diseases such as allergic rhinitis (AR), allergic asthma (AAS), atopic dermatitis (AD), food allergy (FA), and eczema are systemic diseases caused by an impaired immune system. Accompanied by high recurrence rates, the steadily rising incidence rates of these diseases are attracting increasing attention. The pathogenesis of allergic diseases is complex and involves many factors, including maternal-fetal environment, living environment, genetics, epigenetics, and the body's immune status. The pathogenesis of allergic diseases exhibits a marked heterogeneity, with phenotype and endotype defining visible features and associated molecular mechanisms, respectively. With the rapid development of immunology, molecular biology, and biotechnology, many new biological drugs have been designed for the treatment of allergic diseases, including anti-immunoglobulin E (IgE), anti-interleukin (IL)-5, and anti-thymic stromal lymphopoietin (TSLP)/IL-4, to control symptoms. For doctors and scientists, it is becoming more and more important to understand the influencing factors, pathogenesis, and treatment progress of allergic diseases. This review aimed to assess the epidemiology, pathogenesis, and therapeutic interventions of allergic diseases, including AR, AAS, AD, and FA. We hope to help doctors and scientists understand allergic diseases systematically.

Mitochondria signaling pathways in allergic asthma

Mitochondria, as the powerhouse organelle of cells, are greatly involved in regulating cell signaling pathways, including those related to the innate and acquired immune systems, cellular differentiation, growth, death, apoptosis, and autophagy as well as hypoxic stress responses in various diseases. Asthma is a chronic complicated airway disease characterized by airway hyperresponsiveness, eosinophilic inflammation, mucus hypersecretion, and remodeling of airway. The asthma mortality and morbidity rates have increased worldwide, so understanding the molecular mechanisms underlying asthma progression is necessary for new anti-asthma drug development. The lung is an oxygen-rich organ, and mitochondria, by sensing and processing O₂, contribute to the generation of ROS and activation of pro-inflammatory signaling pathways. Asthma pathophysiology has been tightly associated with mitochondrial dysfunction leading to reduced ATP synthase activity, increased oxidative stress, apoptosis induction, and abnormal calcium homeostasis. Defects of the mitochondrial play an essential role in the pro-remodeling mechanisms of lung fibrosis and airway cells’ apoptosis. Identification of mitochondrial therapeutic targets can help repair mitochondrial biogenesis and dysfunction and reverse related pathological changes and lung structural remodeling in asthma. Therefore, we here overviewed the relationship between mitochondrial signaling pathways and asthma pathogenic mechanisms.

Tackling Dysfunction of Mitochondrial Bioenergetics in the Brain

Oxidative phosphorylation (OxPhos) is the basic function of mitochondria, although the landscape of mitochondrial functions is continuously growing to include more aspects of cellular homeostasis. Thanks to the application of -omics technologies to the study of the OxPhos system, novel features emerge from the cataloging of novel proteins as mitochondrial thus adding details to the mitochondrial proteome and defining novel metabolic cellular interrelations, especially in the human brain. We focussed on the diversity of bioenergetics demand and different aspects of mitochondrial structure, functions, and dysfunction in the brain. Definition such as 'mitoexome', 'mitoproteome' and 'mitointeractome' have entered the field of 'mitochondrial medicine'. In this context, we reviewed several genetic defects that hamper the last step of aerobic metabolism, mostly involving the nervous tissue as one of the most prominent energy-dependent tissues and, as consequence, as a primary target of mitochondrial dysfunction. The dual genetic origin of the OxPhos complexes is one of the reasons for the complexity of the genotype-phenotype correlation when facing human diseases associated with mitochondrial defects. Such complexity clinically manifests with extremely heterogeneous symptoms, ranging from organ-specific to multisystemic dysfunction with different clinical courses. Finally, we briefly discuss the future directions of the multi-omics study of human brain disorders.

Reslizumab and Eosinophilic Asthma: One Step Closer to Precision Medicine?

Human eosinophils represent approximately 1% of peripheral blood leukocytes. However, these cells have the propensity to leave the blood stream and migrate into inflamed tissues. Eosinophilic inflammation is present in a significant proportion of patients with severe asthma. Asthma is a chronic inflammatory disorder that affects more than 315 million people worldwide, with 10% having severe uncontrolled disease. Although the majority of patients can be efficiently treated, severe asthmatics continue to be uncontrolled and are at risk of exacerbations and even death. Interleukin-5 (IL-5) plays a fundamental role in eosinophil differentiation, maturation, activation and inhibition of apoptosis. Therefore, targeting IL-5 is an appealing approach to the treatment of patients with severe eosinophilic asthma. Reslizumab, a humanized anti-IL-5 monoclonal antibody, binds with high affinity to amino acids 89–92 of IL-5 that are critical for binding to IL-5 receptor α. Two phase III studies have demonstrated that reslizumab administration in adult patients with severe asthma and eosinophilia (≥400 cells/μL) improved lung function, asthma control, and symptoms. Thus, the use of blood eosinophils as a baseline biomarker could help to select patients with severe uncontrolled asthma who are likely to achieve benefits in asthma control with reslizumab. In conclusion, targeted therapy with reslizumab represents one step closer to precision medicine in patients with severe eosinophilic asthma.

Combining genomewide association study and lung eQTL analysis provides evidence for novel genes associated with asthma

BACKGROUND

Genomewide association studies (GWASs) of asthma have identified single-nucleotide polymorphisms (SNPs) that modestly increase the risk for asthma. This could be due to phenotypic heterogeneity of asthma. Bronchial hyperresponsiveness (BHR) is a phenotypic hallmark of asthma. We aim to identify susceptibility genes for asthma combined with BHR and analyse the presence of cis-eQTLs among replicated SNPs. Secondly, we compare the genetic association of SNPs previously associated with (doctor's diagnosed) asthma to our GWAS of asthma with BHR.

METHODS

A GWAS was performed in 920 asthmatics with BHR and 980 controls. Top SNPs of our GWAS were analysed in four replication cohorts, and lung cis-eQTL analysis was performed on replicated SNPs. We investigated association of SNPs previously associated with asthma in our data.

RESULTS

A total of 368 SNPs were followed up for replication. Six SNPs in genes encoding ABI3BP, NAF1, MICA and the 17q21 locus replicated in one or more cohorts, with one locus (17q21) achieving genomewide significance after meta-analysis. Five of 6 replicated SNPs regulated 35 gene transcripts in whole lung. Eight of 20 asthma-associated SNPs from previous GWAS were significantly associated with asthma and BHR. Three SNPs, in IL-33 and GSDMB, showed larger effect sizes in our data compared to published literature.

CONCLUSIONS

Combining GWAS with subsequent lung eQTL analysis revealed disease-associated SNPs regulating lung mRNA expression levels of potential new asthma genes. Adding BHR to the asthma definition does not lead to an overall larger genetic effect size than analysing (doctor's diagnosed) asthma.

Long-term ambient particle exposures and blood DNA methylation age: findings from the VA normative aging study

BACKGROUND

Ambient particles have been shown to exacerbate measures of biological aging; yet, no studies have examined their relationships with DNA methylation age (DNAm-age), an epigenome-wide DNA methylation based predictor of chronological age.

OBJECTIVE

We examined the relationship of DNAm-age with fine particulate matter (PM2.5), a measure of total inhalable particle mass, and black carbon (BC), a measure of particles from vehicular traffic.

METHODS

We used validated spatiotemporal models to generate 1-year PM2.5 and BC exposure levels at the addresses of 589 older men participating in the VA Normative Aging Study with 1-3 visits between 2000 and 2011 (n = 1032 observations). Blood DNAm-age was calculated using 353 CpG sites from the Illumina HumanMethylation450 BeadChip. We estimated associations of PM2.5 and BC with DNAm-age using linear mixed effects models adjusted for age, lifestyle/environmental factors, and aging-related diseases.

RESULTS

After adjusting for covariates, a 1-µg/m3 increase in PM2.5 (95% CI: 0.30, 0.75, P<0.0001) was significantly associated with a 0.52-year increase in DNAm-age. Adjusted BC models showed similar patterns of association (β = 3.02, 95% CI: 0.48, 5.57, P = 0.02). Only PM2.5 (β = 0.54, 95% CI: 0.24, 0.84, P = 0.0004) remained significantly associated with DNAm-age in two-particle models. Methylation levels from 20 of the 353 CpGs contributing to DNAm-age were significantly associated with PM2.5 levels in our two-particle models. Several of these CpGs mapped to genes implicated in lung pathologies including LZTFL1, PDLIM5, and ATPAF1.

CONCLUSION

Our results support an association of long-termambient particle levels with DNAm-age and suggest that DNAm-age is a biomarker of particle-related physiological processes.

Genes associated with RSV lower respiratory tract infection and asthma: the application of genetic epidemiological methods to understand causality

Infants with respiratory syncytial virus (RSV) lower respiratory tract infections (LRIs) are at increased risk for childhood asthma. The objectives of this article are to review the genes associated with both RSV LRI and asthma, review analytic approaches to assessing shared genetic risk and propose a future perspective on how these approaches can help us to understand the role of infant RSV infection as both an important risk factor for asthma and marker of shared genetic etiology between the two conditions. The review of shared genes and thus pathways associated with severity of response to RSV infection and asthma risk can help us to understand mechanisms of disease and ultimately propose new and novel targets for primary prevention of both diseases.

Contributing factors to the development of childhood asthma: working toward risk minimization

Asthma is the most common chronic disease in childhood, and considerable research has been undertaken to find ways to prevent its development and reduce its prevalence. For such interventions to be successful, risk factors for asthma emergence should be identified and clearly defined. Data are robust for some of them, including atopy, viral infections and exposure to airborne irritants, whereas it is less conclusive for others, such as aeroallergen exposure and bacterial infections. Several interventions for asthma prevention, including avoidance and pharmacotherapy, have been attempted. However, most of them have furnished equivocal results. Various issues hinder the establishment of risk factors for asthma development and reduce the effectiveness of interventions, including the complexity of the disease and the fluidity of the developing systems in childhood. In this review, we revisit the evidence on pediatric asthma risk factors and prevention and discuss issues that perplex this field.

Obesity, metabolic syndrome, and airway disease: a bioenergetic problem?

Multiple studies have determined that obesity increases asthma risk or severity. Metabolic changes of obesity, such as diabetes or insulin resistance, are associated with asthma and poorer lung function. Insulin resistance is also found to increase asthma risk independent of body mass. Conversely, asthma is associated with abnormal glucose and lipid metabolism, insulin resistance, and obesity. Here we review our current understanding of how dietary and lifestyle factors lead to changes in mitochondrial metabolism and cellular bioenergetics, inducing various components of the cardiometabolic syndrome and airway disease.

Introduction to genetics and genomics in asthma: genetics of asthma

While asthma is a heterogeneous disease, a strong genetic basis has been firmly established. Rather than being a single disease entity, asthma consists of related, overlapping syndromes [Barnes (Proc Am Thor Soc 8:143-148, 2011)] including three general domains: variable airway obstruction, airway hyper-responsiveness, and airway inflammation with a considerable proportion, but not all, of asthma being IgE-mediated further adding to its heterogeneity. This chapter reviews the approaches to the elucidation of genetics of asthma from the early evidence of familial clustering to the current state of knowledge with genome-wide approaches. The conclusion is that research efforts have led to a tremendous repository of genetic determinants of asthma, most of which fall into the above phenotypic domains of the syndrome. We now look to future integrative approaches of genetics, genomics (Chap. 10), and epigenetics (Chap. 11) to better understand the causal mechanism through which, these genetic loci act in manifesting asthma.

Asthma genetics and personalised medicine

Unbiased genetic approaches, especially genome-wide association studies, have identified novel genetic targets in the pathogenesis of asthma, but so far these targets account for only a small proportion of the heritability of asthma. Recognition of the importance of disease heterogeneity, the need for improved disease phenotyping, and the fact that genes involved in the inception of asthma are likely to be different from those involved in severity widens the scope of asthma genetics. The identification of genes implicated in several causal pathways suggests that genetic scores could be used to capture the effect of genetic variations on individuals. Gene-environment interaction adds another layer of complexity, which is being successfully explored by epigenetic approaches. Pharmacogenetics is one example of how gene-environment interactions are already being taken into account in the identification of drug responders and non-responders, and patients most susceptible to adverse effects. Such applications represent one component of personalised medicine, an approach that places the individual at the centre of health care.

Genome-wide association studies in asthma; perhaps, the end of the beginning

PURPOSE OF REVIEW

A large number of genetic loci contribute towards an individual's susceptibility to asthma and other complex diseases. Genome-wide association studies (GWASs) have provided us with a wealth of loci associated with asthma susceptibility, asthma endotypes and responsiveness to asthma medications. The reproducibility of these genetic loci across different studies highlights the interplay of general and population-specific risk alleles in asthma. Although GWASs have been successful in identifying disease-associated loci, there is still large potential for such studies to provide further insights into asthma pathogenesis.

RECENT FINDINGS

GWASs over the past year have extended study design well beyond the simple case-control and continuous phenotype association formats, for example, including interactions with environmental factors, integrating GWAS data with epigenetic data and GWASs in animal models, incorporating pathway analyses and utilising emerging sequencing technologies.

SUMMARY

Moving beyond traditional GWAS formats is likely to significantly enhance our understanding of the genetic basis for asthma. This review discusses where we are after half a decade of asthma GWASs, and focuses on advances over the past year that show where the GWAS field is headed in the future.

Expression data analysis to identify biomarkers associated with asthma in children

Asthma is characterized by recurrent episodes of wheezing, shortness of breath, chest tightness, and coughing. It is usually caused by a combination of complex and incompletely understood environmental and genetic interactions. We obtained gene expression data with high-throughput screening and identified biomarkers of children's asthma using bioinformatics tools. Next, we explained the pathogenesis of children's asthma from the perspective of gene regulatory networks: DAVID was applied to perform Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enriching analysis for the top 3000 pairs of relationships in differentially regulatory network. Finally, we found that HAND1, PTK1, NFKB1, ZIC3, STAT6, E2F1, PELP1, USF2, and CBFB may play important roles in children's asthma initiation. On account of regulatory impact factor (RIF) score, HAND1, PTK7, and ZIC3 were the potential asthma-related factors. Our study provided some foundations of a strategy for biomarker discovery despite a poor understanding of the mechanisms underlying children's asthma.

Ultrastructural changes of airway in murine models of allergy and diet-induced metabolic syndrome

Studying ultrastructural changes could reveal novel pathophysiology of obese-asthmatic condition as existing concepts in asthma pathogenesis are based on the histological changes of the diseased airway. While asthma is defined in functional terms, the potential of electron microscopy (EM) in providing cellular and subcellular detail is underutilized. With this view, we have performed transmission EM in the lungs from allergic mice that show key features of asthma and high-fat- or high-fructose-fed mice that mimicked metabolic syndrome to illustrate the ultrastructural changes. The primary focus was epithelial injury and metaplasia, which are cardinal features of asthma and initiate airway remodeling. EM findings of the allergically inflamed mouse lungs correlate with known features of human asthma such as increased mitochondria in airway smooth muscle, platelet activation and subepithelial myofibroblasts. Interestingly, we found a clear and unambiguous evidence to suggest that ciliated cells can become goblet cells using immunoelectron microscopy. Additionally, we show for the first time the stressed mitochondria in the bronchial epithelia of high-fat- or high-fructose-fed mice even without allergen exposure. These results may stimulate interest in using EM in understanding novel pathological mechanisms for different subtypes of asthma including obese asthma.

Genetics of onset of asthma

PURPOSE OF REVIEW

Most asthma starts early in life. Defining phenotypes of asthma at this age is difficult as many preschool children have asthma-like respiratory symptoms. This review discusses progress in defining early wheezing phenotypes and describes genetic factors associated with the age of onset of asthma.

RECENT FINDINGS

Latent class analyses confirmed transient and persistent wheezing phenotypes, and identified a novel intermediate-onset wheezing phenotype that was strongly associated with atopy and asthma at age 8 years. However, no single cross-sectional or longitudinal definition of respiratory symptoms in childhood strongly predicts asthma later in life. Genome-wide association (GWA) studies have identified a locus on chromosome 17q12-21 (encoding ORMDL3 and GSDMB) as a risk factor for predominantly childhood-onset asthma, but not for atopy, and overall not for adult-onset asthma. Other loci found by GWA studies appear to increase asthma risk both in children and adults. Atopy genes do not explain early-onset asthma.

SUMMARY

Although most asthma starts early in life, no valid test is able to identify asthma at that age period. GWA studies have provided more insight into the unique and common genetic origins of adult-onset and childhood-onset asthma. The 17q12-21 locus is predominantly associated with childhood-onset asthma.

Mitochondrial dysfunction in metabolic syndrome and asthma

Though severe or refractory asthma merely affects less than 10% of asthma population, it consumes significant health resources and contributes significant morbidity and mortality. Severe asthma does not fell in the routine definition of asthma and requires alternative treatment strategies. It has been observed that asthma severity increases with higher body mass index. The obese-asthmatics, in general, have the features of metabolic syndrome and are progressively causing a significant burden for both developed and developing countries thanks to the westernization of the world. As most of the features of metabolic syndrome seem to be originated from central obesity, the underlying mechanisms for metabolic syndrome could help us to understand the pathobiology of obese-asthma condition. While mitochondrial dysfunction is the common factor for most of the risk factors of metabolic syndrome, such as central obesity, dyslipidemia, hypertension, insulin resistance, and type 2 diabetes, the involvement of mitochondria in obese-asthma pathogenesis seems to be important as mitochondrial dysfunction has recently been shown to be involved in airway epithelial injury and asthma pathogenesis. This review discusses current understanding of the overlapping features between metabolic syndrome and asthma in relation to mitochondrial structural and functional alterations with an aim to uncover mechanisms for obese-asthma.

Advances in pediatric asthma in 2011: moving forward

Last year's "Advances in pediatric asthma" concluded with the following statement: "Perhaps new directions in personalized medicine and improved health care access and communication will help maintain steady progress in alleviating the burden of this disease in children, especially young children." This year's summary will focus on recent advances in pediatric asthma that show significant accomplishments in reducing asthma morbidity and mortality over the last 10 years and discuss some pathways to further reduce asthma burden, as indicated in Journal of Allergy and Clinical Immunology publications in 2011. Some of the recent reports continue to shed light on methods to improve asthma management through steps to reduce asthma exacerbations, identify features of the disease in early childhood, alter asthma progression, intervene with nutrition, and more effectively implement the asthma guidelines. As new information evolves, it is also time to consider a revision of the asthma guidelines based on key studies that affect our management of the disease since the last revision in 2007. Now is also the time to use information recorded in electronic medical records to develop innovative disease management plans that will track asthma over time and enable timely decisions on interventions to maintain control that can lead to disease remission and prevention.

Advances in adult asthma diagnosis and treatment and health outcomes, education, delivery, and quality in 2011: what goes around comes around

Last year's review of research advances in adults with asthma emphasized the linear trajectory of translation: the initial studies translating bench findings to the first patients (T1) are connected to larger efficacy studies, including clinical trials studying subjects under tightly controlled conditions (T2), and these in turn are connected to research, including comparative effectiveness research, that tests how the efficacy findings of T2 research fare in the real world, diverse populations, and varied practice settings (T3). This year what was observed was a more interwoven relationship (rather than a linear one), in which each translational level informs the others and new approaches to answering old questions have led to new discoveries. Within this framework, the present review summarizes clinical research on asthma in adults that was reported in the Journal of Allergy and Clinical Immunology in 2011, with emphasis on health outcomes, education, delivery, and quality in terms of discoveries related to mechanisms of disease, environmental exposures, and management.

Human apolipoprotein E genotypes differentially modify house dust mite-induced airway disease in mice

Apolipoprotein E (apoE) is an endogenous negative regulator of airway hyperreactivity (AHR) and mucous cell metaplasia in experimental models of house dust mite (HDM)-induced airway disease. The gene encoding human apoE is polymorphic, with three common alleles (ε2, ε3, and ε4) reflecting single amino acid substitutions at amino acids 112 and 158. The objective of this study was to assess whether the human apoE alleles modify airway responses to repeated nasal HDM challenges. Mice expressing the human apoE ε2 (huApoE2), ε3 (huApoE3), or ε4 (huApoE4) alleles received nasal HDM challenges, and airway responses were compared with mice expressing the endogenous murine apoE gene (muApoE). huApoE3 mice displayed significant reductions in AHR, mucous cell metaplasia, and airway inflammation compared with muApoE mice. The attenuated severity of airway inflammation in huApoE3 mice was associated with reductions in lung mRNA levels of Th2 and Th17 cytokines, as well as chemokines (CCL7, CCL11, CCL24). huApoE4 mice had an intermediate phenotype, with attenuated AHR and IgE production, compared with muApoE mice, whereas airway inflammation and mucous cell metaplasia were not reduced. In contrast, HDM-induced airway responses were not modified in mice expressing the huApoE2 allele. We conclude that the polymorphic huApoE alleles differentially modulate HDM-induced airway disease, which can be stratified, in rank order of increasing disease severity, ε3 < ε4 < ε2. These results raise the possibility that the polymorphic apoE alleles may modify disease severity in human asthma.