Unique Allergic Asthma Phenotypes in Offspring of House Dust Mite-exposed Mice

Maternal asthma during pregnancy and risks of allergy and asthma in progeny: A systematic review and meta-analysis

BACKGROUND

Clinical and preclinical evidence indicate that in utero maternal asthma exposure increases progeny asthma risk. Whether maternal asthma also increases the risks of progeny allergy is unclear.

OBJECTIVES

To synthesise the available evidence on the relationship between in utero exposure to maternal asthma and postnatal asthma, wheezing and allergic diseases (Prospero: CRD42020201538).

SEARCH STRATEGY

We systematically searched MEDLINE [PubMed], Embase [Ovid], Web of Science, Informit Health, the Cochrane Library, CINAHL [EBSCOhost], MedNar [Deep Web Technologies], ProQuest Theses and Dissertations, Scopus [Elsevier] and Trove, to the end of 2023.

SELECTION CRITERIA

Studies reporting asthma, wheeze and/or allergic disease in progeny of women with and without asthma or with asthma classified by control, exacerbation or severity.

DATA COLLECTION AND ANALYSIS

Double screening, selection, data extraction and quality assessment were performed, using Joanna Briggs Institute (JBI) scoring.

MAIN RESULTS

Of 134 non-overlapping studies, 127 were included in ≥1 meta-analysis. Maternal asthma ever was associated with greater risks of asthma (65 studies, risk ratio [95% confidence interval] 1.76 [1.57-1.96]), wheeze (35 studies, 1.59 [1.52-1.66]), food allergy (5 studies, 1.32 [1.23-1.40]), allergic rhinitis (7 studies, 1.18 [1.06-1.31]) and allergic dermatitis (14 studies, 1.17 [1.11-1.23]) ever in progeny. Asthma during the pregnancy, more severe, and uncontrolled maternal asthma were each associated with greater risks of progeny asthma.

CONCLUSIONS

Children of mothers with asthma are at increased risk for the development of allergic diseases. Whether improved maternal asthma control reduces risks of child allergy as well as asthma requires further investigation.

The Prevention of House Dust Mite Allergies in Pediatric Asthma

This review provides a concise overview of preventive measures against dust mite allergies in pediatric populations, emphasizing the need for a comprehensive and evolving approach. Dust mites, ubiquitous microscopic arachnids, pose a significant threat to children's health, triggering allergies and asthma. Traditional preventive strategies such as regular cleaning, mattress covers, and humidity control are essential but warrant refinement. Empowering children through personalized hygiene education and exploring innovative bedding solutions showcase a forward-thinking paradigm. Collaboration with healthcare professionals and embracing technology-driven solutions ensures a holistic and adaptable approach to safeguarding pediatric health against dust mite-related ailments. This abstract underscores the importance of continually reassessing and innovating preventive measures to create resilient and health-conscious living environments for children.

Preclinical models of maternal asthma and progeny outcomes: a scoping review

There is an increased risk of adverse perinatal outcomes in the ∼17% of women with asthma during pregnancy. The mechanisms linking maternal asthma and adverse outcomes are largely unknown, but reflect joint effects of genetics and prenatal exposure to maternal asthma. Animal models are essential to understand the underlying mechanisms independent of genetics and comorbidities, and enable safe testing of interventions. This scoping review aimed to explore the methodology, phenotype, characteristics, outcomes and quality of published studies using preclinical maternal asthma models. MEDLINE (PubMed), Embase (Elsevier) and Web of Science were systematically searched using previously validated search strings for maternal asthma and for animal models. Two reviewers independently screened titles and abstracts, full texts, and then extracted and assessed the quality of each study using the Animal Research: Reporting of In Vivo Experiments (ARRIVE) 2.0 guidelines. Out of 3618 studies identified, 39 were eligible for extraction. Most studies were in rodents (86%) and all were models of allergic asthma. Maternal and progeny outcomes included airway hyperresponsiveness, airway resistance, inflammation, lung immune cells, lung structure and serum immunoglobulins and cytokines. Experimental design (100%), procedural details (97%) and rationale (100%) were most often reported. Conversely, data exclusion (21%), blinding (18%) and adverse events (8%) were reported in a minority of studies. Species differences in physiology and timing of development, the use of allergens not relevant to humans and a lack of comparable outcome measures may impede clinical translation. Future studies exploring models of maternal asthma should adhere to the minimum core outcomes set presented in this review.

The impact of maternal asthma on the fetal lung: Outcomes, mechanisms and interventions

Maternal asthma affects up to 17% of pregnancies and is associated with adverse infant, childhood, and adult respiratory outcomes, including increased risks of neonatal respiratory distress syndrome, childhood wheeze and asthma. In addition to genetics, these poor outcomes are likely due to the mediating influence of maternal asthma on the in-utero environment, altering fetal lung and immune development and predisposing the offspring to later lung disease. Maternal asthma may impair glucocorticoid signalling in the fetus, a process critical for lung maturation, and increase fetal exposure to proinflammatory cytokines. Therefore, interventions to control maternal asthma, increase glucocorticoid signalling in the fetal lung, or Vitamin A, C, and D supplementation to improve alveologenesis and surfactant production may be beneficial for later lung function. This review highlights potential mechanisms underlying maternal asthma and offspring respiratory morbidities and describes how pregnancy interventions can promote optimal fetal lung development in babies of asthmatic mothers.

Grandmaternal allergen sensitization reprograms epigenetic and airway responses to allergen in second-generation offspring

Asthma susceptibility is influenced by environmental, genetic, and epigenetic factors. DNA methylation is one form of epigenetic modification that regulates gene expression and is both inherited and modified by environmental exposures throughout life. Prenatal development is a particularly vulnerable time period during which exposure to maternal asthma increases asthma risk in offspring. How maternal asthma affects DNA methylation in offspring and what the consequences of differential methylation are in subsequent generations are not fully known. In this study, we tested the effects of grandmaternal house dust mite (HDM) allergen sensitization during pregnancy on airway physiology and inflammation in HDM-sensitized and challenged second-generation mice. We also tested the effects of grandmaternal HDM sensitization on tissue-specific DNA methylation in allergen-naïve and -sensitized second-generation mice. Descendants of both allergen- and vehicle-exposed grandmaternal founders exhibited airway hyperreactivity after HDM sensitization. However, grandmaternal allergen sensitization significantly potentiated airway hyperreactivity and altered the epigenomic trajectory in second-generation offspring after HDM sensitization compared with HDM-sensitized offspring from vehicle-exposed founders. As a result, biological processes and signaling pathways associated with epigenetic modifications were distinct between lineages. A targeted analysis of pathway-associated gene expression found that Smad3 was significantly dysregulated as a result of grandmaternal allergen sensitization. These data show that grandmaternal allergen exposure during pregnancy establishes a unique epigenetic trajectory that reprograms allergen responses in second-generation offspring and may contribute to asthma risk.NEW & NOTEWORTHY Asthma susceptibility is influenced by environmental, genetic, and epigenetic factors. This study shows that maternal allergen exposure during pregnancy promotes unique epigenetic trajectories in second-generation offspring at baseline and in response to allergen sensitization, which is associated with the potentiation of airway hyperreactivity. These effects are one mechanism by which maternal asthma may influence the inheritance of asthma risk.

Illuminating Airway Nerve Structure and Function in Chronic Cough

Airway nerves regulate vital airway functions including bronchoconstriction, cough, and control of respiration. Dysregulation of airway nerves underlies the development and manifestations of airway diseases such as chronic cough, where sensitization of neural pathways leads to excessive cough triggering. Nerves are heterogeneous in both expression and function. Recent advances in confocal imaging and in targeted genetic manipulation of airway nerves have expanded our ability to visualize neural organization, study neuro-immune interactions, and selectively modulate nerve activation. As a result, we have an unprecedented ability to quantitatively assess neural remodeling and its role in the development of airway disease. This review highlights our existing understanding of neural heterogeneity and how advances in methodology have illuminated airway nerve morphology and function in health and disease.

Preclinical models of maternal asthma and progeny outcomes: a scoping review protocol

OBJECTIVE

This scoping review will describe the methodology, phenotype, and characteristics of maternal asthma models used in preclinical studies and the outcomes that have been measured in the mother and progeny. The review This will identify gaps in knowledge of maternal and progeny outcomes following maternal asthma in pregnancy.

INTRODUCTION

Maternal asthma affects up to 17% of pregnancies worldwide and is associated with adverse perinatal outcomes in mothers and babies, including pre-eclampsia, gestational diabetes, cesarean section, preterm birth, small for gestational age, nursery admission, and neonatal death. While the associations are well established, the mechanisms linking maternal asthma and adverse perinatal outcomes are largely unknown due to the difficulties of human mechanistic studies. The appropriate selection of animal models is vital to understanding the mechanisms underlying associations between human maternal asthma and adverse perinatal outcomes.

INCLUSION CRITERIA

This review will include primary studies published in English where outcomes have been studied in vivo in non-human mammalian species.

METHODS

This review will follow the JBI methodology for scoping reviews. We will search MEDLINE (PubMed), Embase, and Web of Science to identify papers published before the end of 2022. Initial keywords will include pregnancy, gestation, asthma , and wheeze , as well as validated search strings to identify papers that describe animal models. Extracted data will include information on methods used to induce maternal asthma; asthmatic phenotypes and characteristics; and maternal, pregnancy, placental, and progeny outcomes. The characteristics of each study will be presented in summary tables and a core outcome list to assist researchers in developing, reporting, and comparing future animal studies of maternal asthma.

REVIEW REGISTRATION

Open Science Framework osf.io/trwk5.

DOCK2 Promotes Asthma Development by Eliciting Airway Epithelial-Mesenchymal Transition

Epithelial-mesenchymal transition (EMT) contributes to airway remodeling, a predominant feature of asthma. DOCK2 (dedicator of cytokinesis 2) is an innate immune signaling molecule involved in vascular remodeling. However, it is unknown if DOCK2 plays a role in airway remodeling during asthma development. In this study, we found that DOCK2 is highly induced in both normal human bronchial epithelial cells treated with house dust mite (HDM) extract and human asthmatic airway epithelium. DOCK2 is also upregulated by TGF-β1 (transforming growth factor β1) during EMT of human bronchial epithelial cells. Importantly, knockdown of DOCK2 inhibits, and overexpression of DOCK2 promotes, TGF-β1-induced EMT. Consistently, DOCK2 deficiency suppresses the EMT of airway epithelium, attenuates the subepithelial fibrosis, and improves pulmonary function in HDM-induced asthmatic lungs. These data suggest that DOCK2 plays an important role in EMT and asthma development. Mechanistically, DOCK2 interacts with transcription factor FoxM1 (forkhead box M1), which enhances FoxM1 binding to mesenchymal marker gene promoters and further promotes mesenchymal marker gene transcription and expression, leading to EMT. Taken together, our study identifies DOCK2 as a novel regulator for airway EMT in an HDM-induced asthma model, thus providing a potential therapeutic target for treatment of asthma.