A role for Wnt signaling genes in the pathogenesis of impaired lung function in asthma

The contribution of the WNT pathway to the therapeutic effects of montelukast in experimental murine airway inflammation induced by ovalbumin and lipopolysaccharide

The wingless/integrase-1 (WNT) pathway involved in the pathogenesis of inflammatory airway diseases has recently generated considerable research interest. Montelukast, a leukotriene receptor antagonist, provides therapeutic benefits in allergic asthma involving eosinophils. We aimed to investigate the role of the WNT pathway in the therapeutic actions of montelukast (MT) in a mixed type of allergic-acute airway inflammation model induced by ovalbumin (OVA) and lipopolysaccharide (LPS) in mice. Female mice were sensitized with intraperitoneal OVA-Al(OH)3 administration in the initiation phase and intranasal OVA followed by LPS administration in the challenge phase. The mice were divided into eight groups: control, asthmatic, and control/asthmatic treated with XAV939 (inhibitor of the canonical WNT pathway), LGK-974 (inhibitor of the secretion of WNT ligands), or MT at different doses. The inhibition of the WNT pathway prevented tracheal 5-HT and bradykinin hyperreactivity, while only the inhibition of the canonical WNT pathway partially reduced 5-HT and bradykinin contractions compared to the inflammation group. Therefore, MT treatment hindered 5-HT and bradykinin hyperreactivity associated with airway inflammation. Furthermore, MT prevented the increases in the phosphorylated GSK-3β and WNT5A levels, which had been induced by airway inflammation, in a dose-dependent manner. Conversely, the MT application caused a further increase in the fibronectin levels, while there was no significant alteration in the phosphorylation of the Smad-2 levels in the isolated lungs of the mice. The MT treatment reversed the increase in the mRNA expression levels of interleukin-17A. An increase in eosinophil and neutrophil counts was observed in bronchoalveolar lavage fluid samples obtained from the mice in the inflammation group, which was hampered by the MT treatment. The inhibition of the WNT pathway did not alter inflammatory cytokine expression or cell infiltration. The WNT pathway mediated the therapeutic effects of MT due to the inhibition of GSK-3β phosphorylation as well as the reduction of WNT5A levels in a murine airway inflammation model.

WISP1 induces the expression of macrophage migration inhibitory factor in human lung fibroblasts through Src kinases and EGFR-activated signaling pathways

Wnt1-inducible signaling protein 1 (WISP1/CCN4) is a secreted matricellular protein that is implicated in lung and airway remodeling. The macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine that has been associated with chronic lung diseases. In this study, we aimed to investigate the WISP1 signaling pathway and its ability to induce the expression of MIF in primary cultures of fibroblasts from normal human lungs (HLFs). Our results showed that WISP1 significantly stimulated the expression of MIF in a concentration- and time-dependent fashion. In WISP1-induced expression of MIF, αvβ5-integrin and chondroitin sulfate proteoglycans as well as Src tyrosine kinases, MAP kinases, phosphatidylinositol 3-kinase/Akt, PKC, and NF-κB were involved. WISP1-induced expression of MIF was attenuated in the presence of the Src kinase inhibitor PP2 or the MIF tautomerase activity inhibitor ISO-1. Moreover, WISP1 significantly increased the phosphorylation and activation of EGF receptor (EGFR) through transactivation by Src kinases. WISP1 also induced the expression of MIF receptor CD74 and coreceptor CD44, through which MIF exerts its effects on HLFs. In addition, it was found that MIF induced its own expression, as well as its receptors CD74/CD44, acting in an autocrine manner. Finally, WISP1-induced MIF promoted the expression of cyclooxygenase 2, prostaglandin E2, IL-6, and matrix metalloproteinase-2 demonstrating the regulatory role of WISP1-MIF axis in lung inflammation and remodeling involving mainly integrin αvβ5, Src kinases, PKC, NF-κB, and EGFR. The specific signaling pathways involved in WISP1-induced expression of MIF may prove to be excellent candidates for novel targets to control inflammation in chronic lung diseases.NEW & NOTEWORTHY The present study demonstrates for the first time that Wnt1-inducible signaling protein 1 (WISP1) regulates migration inhibitory factor (MIF) expression and activity and identifies the main signaling pathways involved. The newly discovered WISP1-MIF axis may drive lung inflammation and could result in the design of novel targeted therapies in inflammatory lung diseases.

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.

Oropharyngeal Microbiota Clusters in Children with Asthma or Wheeze Associate with Allergy, Blood Transcriptomic Immune Pathways, and Exacerbation Risk

Rationale: Children with preschool wheezing or school-age asthma are reported to have airway microbial imbalances. Objectives: To identify clusters in children with asthma or wheezing using oropharyngeal microbiota profiles. Methods: Oropharyngeal swabs from the U-BIOPRED (Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes) pediatric asthma or wheezing cohort were characterized using 16S ribosomal RNA gene sequencing, and unsupervised hierarchical clustering was performed on the Bray-Curtis β-diversity. Enrichment scores of the Molecular Signatures Database hallmark gene sets were computed from the blood transcriptome using gene set variation analysis. Children with severe asthma or severe wheezing were followed up for 12-18 months, with assessment of the frequency of exacerbations. Measurements and Main Results: Oropharyngeal samples from 241 children (age range, 1-17 years; 40% female) revealed four taxa-driven clusters dominated by Streptococcus, Veillonella, Rothia, and Haemophilus. The clusters showed significant differences in atopic dermatitis, grass pollen sensitization, FEV1% predicted after salbutamol, and annual asthma exacerbation frequency during follow-up. The Veillonella cluster was the most allergic and included the highest percentage of children with two or more exacerbations per year during follow-up. The oropharyngeal clusters were different in the enrichment scores of TGF-β (transforming growth factor-β) (highest in the Veillonella cluster) and Wnt/β-catenin signaling (highest in the Haemophilus cluster) transcriptomic pathways in blood (all q values <0.05). Conclusions: Analysis of the oropharyngeal microbiota of children with asthma or wheezing identified four clusters with distinct clinical characteristics (phenotypes) that associate with risk for exacerbation and transcriptomic pathways involved in airway remodeling. This suggests that further exploration of the oropharyngeal microbiota may lead to novel pathophysiologic insights and potentially new treatment approaches.

Intrauterine Smoke Exposure, microRNA Expression during Human Lung Development, and Childhood Asthma

Intrauterine smoke (IUS) exposure during early childhood has been associated with a number of negative health consequences, including reduced lung function and asthma susceptibility. The biological mechanisms underlying these associations have not been established. MicroRNAs regulate the expression of numerous genes involved in lung development. Thus, investigation of the impact of IUS on miRNA expression during human lung development may elucidate the impact of IUS on post-natal respiratory outcomes. We sought to investigate the effect of IUS exposure on miRNA expression during early lung development. We hypothesized that miRNA-mRNA networks are dysregulated by IUS during human lung development and that these miRNAs may be associated with future risk of asthma and allergy. Human fetal lung samples from a prenatal tissue retrieval program were tested for differential miRNA expression with IUS exposure (measured using placental cotinine concentration). RNA was extracted and miRNA-sequencing was performed. We performed differential expression using IUS exposure, with covariate adjustment. We also considered the above model with an additional sex-by-IUS interaction term, allowing IUS effects to differ by male and female samples. Using paired gene expression profiles, we created sex-stratified miRNA-mRNA correlation networks predictive of IUS using DIABLO. We additionally evaluated whether miRNAs were associated with asthma and allergy outcomes in a cohort of childhood asthma. We profiled pseudoglandular lung miRNA in n = 298 samples, 139 (47%) of which had evidence of IUS exposure. Of 515 miRNAs, 25 were significantly associated with intrauterine smoke exposure (q-value < 0.10). The IUS associated miRNAs were correlated with well-known asthma genes (e.g., ORM1-Like Protein 3, ORDML3) and enriched in disease-relevant pathways (oxidative stress). Eleven IUS-miRNAs were also correlated with clinical measures (e.g., Immunoglobulin E andlungfunction) in children with asthma, further supporting their likely disease relevance. Lastly, we found substantial differences in IUS effects by sex, finding 95 significant IUS-miRNAs in male samples, but only four miRNAs in female samples. The miRNA-mRNA correlation networks were predictive of IUS (AUC = 0.78 in males and 0.86 in females) and suggested that IUS-miRNAs are involved in regulation of disease-relevant genes (e.g., A disintegrin and metalloproteinase domain 19 (ADAM19), LBH regulator of WNT signaling (LBH)) and sex hormone signaling (Coactivator associated methyltransferase 1(CARM1)). Our study demonstrated differential expression of miRNAs by IUS during early prenatal human lung development, which may be modified by sex. Based on their gene targets and correlation to clinical asthma and atopy outcomes, these IUS-miRNAs may be relevant for subsequent allergy and asthma risk. Our study provides insight into the impact of IUS in human fetal lung transcriptional networks and on the developmental origins of asthma and allergic disorders.

Wingless/integrase-1 signaling in allergic asthma and pediatric lung diseases

PURPOSE OF REVIEW

To provide an update on the current understanding of the role of wingless/integrase-1 (Wnt) signaling in pediatric allergic asthma and other pediatric lung diseases.

RECENT FINDINGS

The Wnt signaling pathway is critical for normal lung development. Genetic and epigenetic human studies indicate a link between Wnt signaling and the development and severity of asthma in children. Mechanistic studies using animal models of allergic asthma demonstrate a key role for Wnt signaling in allergic airway inflammation and remodeling. More recently, data on bronchopulmonary dysplasia (BPD) pathogenesis points to the Wnt signaling pathway as an important regulator.

SUMMARY

Current data indicates that the Wnt signaling pathway is an important mediator in allergic asthma and BPD pathogenesis. Further studies are needed to characterize the roles of individual Wnt signals in childhood disease, and to identify potential novel therapeutic targets to slow or prevent disease processes.

Is IIIG9 a New Protein with Exclusive Ciliary Function? Analysis of Its Potential Role in Cancer and Other Pathologies

The identification of new proteins that regulate the function of one of the main cellular phosphatases, protein phosphatase 1 (PP1), is essential to find possible pharmacological targets to alter phosphatase function in various cellular processes, including the initiation and development of multiple diseases. IIIG9 is a regulatory subunit of PP1 initially identified in highly polarized ciliated cells. In addition to its ciliary location in ependymal cells, we recently showed that IIIG9 has extraciliary functions that regulate the integrity of adherens junctions. In this review, we perform a detailed analysis of the expression, localization, and function of IIIG9 in adult and developing normal brains. In addition, we provide a 3D model of IIIG9 protein structure for the first time, verifying that the classic structural and conformational characteristics of the PP1 regulatory subunits are maintained. Our review is especially focused on finding evidence linking IIIG9 dysfunction with the course of some pathologies, such as ciliopathies, drug dependence, diseases based on neurological development, and the development of specific high-malignancy and -frequency brain tumors in the pediatric population. Finally, we propose that IIIG9 is a relevant regulator of PP1 function in physiological and pathological processes in the CNS.

Aerosol inhalation of Mycobacterium vaccae ameliorates airway structural remodeling in chronic asthma mouse model

Background: Airway remodeling is accepted to be a determining component within the natural history of asthma. Nebulized inhalation of Mycobacterium vaccae (M. vaccae) has a protective effect on asthmatic mice. However, little is known regarding the effect of M. vaccae on airway structural remodeling in asthmatic mice. The purpose of this study was to explore the effect and the underlying mechanism of M. vaccae aerosol inhalation on airway structural remodeling in an asthma mouse model. Methods: Chronic asthma mouse models were established by ovalbumin induction. The number of inflammatory cells in bronchoalveolar lavage fluid (BALF), pathological alterations in lung tissue, and levels of associated cytokines (IL-5, IL-13, TNF-α, and ovalbumin-specific immunoglobulin E [OVA-sIgE]) were all assessed after M. vaccae therapy. The relative expression of interleukin (IL)-1β, tumor necrosis factor-alpha (TNF-α), nuclear factor kappa B (NF-κB), and Wnt1-induced signaling protein 1 (WISP1) mRNA were detected. Western blotting and immunohistochemistry detected the expression of Wnt/β-catenin pathway-related proteins in lung tissue. Results: M. vaccae aerosol inhalation relieved airway inflammation, airway hyper-responsiveness, and airway remodeling. M. vaccae reduced the levels of IL-5, IL-13, TNF-α, and OVA-sIgE in and downregulated the expression of IL-1β, TNF-α, NF-κB, and WISP1 mRNA in the pulmonary. In addition, M. vaccae inhibited the expression of β-catenin, WISP1, and Wnt1 protein and upregulated the expression of glycogen synthase kinase-3beta (GSK-3β). Conclusion: Nebulized inhalation of M. vaccae can reduce airway remodeling during asthma.

Newborn DNA methylation and asthma acquisition across adolescence and early adulthood

BACKGROUND

Little is known about the association of newborn DNA methylation (DNAm) with asthma acquisition across adolescence and early adult life.

OBJECTIVE

We aim to identify epigenetic biomarkers in newborns for asthma acquisition during adolescence or young adulthood.

METHODS

The Isle of Wight Birth Cohort (IOWBC) (n = 1456) data at ages 10, 18 and 26 years were assessed. To screen cytosine-phosphate-guanine site (CpGs) potentially associated with asthma acquisition, at the genome scale, we examined differentially methylated regions (DMR) using dmrff R package and individual CpG sites using linear regression on such associations. For CpGs that passed screening, we examined their enrichment in biological pathways using their mapping genes and tested their associations with asthma acquisitions using logistic regressions. Findings in IOWBC were tested in an independent cohort, the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort.

RESULTS

In total, 2636 unique CpGs passed screening, based on which we identified one biological pathway linked to asthma acquisition during adolescence in females (FDR adjusted p-value = .003 in IOWBC). Via logistic regressions, for females, four CpGs were shown to be associated with asthma acquisition during adolescence, and another four CpGs with asthma acquisition in young adulthood (FDR adjusted p-value < .05 in IOWBC) and these eight CpGs were replicated in ALSPAC (all p-values < .05). DNAm at all the identified CpGs was shown to be temporally consistent, and at six of the CpGs was associated with expressions of adjacent or mapping genes in females (all p-values < .05). For males, 622 CpGs were identified in IOWBC (FDR = 0.01), but these were not tested in ALSPAC due to small sample sizes.

CONCLUSION AND CLINICAL RELEVANCE

Eight CpGs on LHX5, IL22RA2, SOX11, CBX4, ACPT, CFAP46, MUC4, and ATP1B2 genes have the potential to serve as candidate epigenetic biomarkers in newborns for asthma acquisition in females during adolescence or young adulthood.

The Role of Secreted Frizzled Related Protein-1 in Allergic Asthma

Although allergic asthma is a highly prevalent chronic inflammatory condition, the underlying pathogenesis driving Th2 type inflammation is not well understood. Wnt/β-catenin signaling has been implicated, but the influence of individual members of the pathway is not clear. We hypothesized that Secreted Frizzled Related Protein-1 (SFRP-1), a Wnt signaling modulator, plays an important role in the development of allergic inflammation in asthma. Using an in vivo house dust mite asthma model, SFRP-1-/- mice were sensitized, and their bronchoalveolar lavage fluid was collected for evaluation of airway inflammation. SFRP-1-/- mice exhibited less inflammation, with reduced cellular infiltration and concentration of IL-5 in bronchoalveolar lavage fluid, compared to wild type (WT) mice. Similar findings were observed in WT mice treated with SFRP-1 inhibitor, WAY316606. Alveolar macrophages from sensitized SFRP-1-/- mice demonstrated reduced alternative polarization compared to wild WT, indicating that macrophages could mediate the alteration in inflammation seen in these mice. These findings suggest that SFRP-1 is an important potentiator of asthmatic airway inflammation.

Role of Non-Coding RNAs in Post-Transcriptional Regulation of Lung Diseases

Non-coding RNAs (ncRNAs), notably microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), have recently gained increasing consideration because of their versatile role as key regulators of gene expression. They adopt diverse mechanisms to regulate transcription and translation, and thereby, the function of the protein, which is associated with several major biological processes. For example, proliferation, differentiation, apoptosis, and metabolic pathways demand fine-tuning for the precise development of a specific tissue or organ. The deregulation of ncRNA expression is concomitant with multiple diseases, including lung diseases. This review highlights recent advances in the post-transcriptional regulation of miRNAs and lncRNAs in lung diseases such as asthma, chronic obstructive pulmonary disease, cystic fibrosis, and idiopathic pulmonary fibrosis. Further, we also discuss the emerging role of ncRNAs as biomarkers as well as therapeutic targets for lung diseases. However, more investigations are required to explore miRNAs and lncRNAs interaction, and their function in the regulation of mRNA expression. Understanding these mechanisms might lead to early diagnosis and the development of novel therapeutics for lung diseases.

The Effects of WISP1 Polymorphisms on the Prognosis of Lung Cancer Patients with Platinum-Based Chemotherapy

Purpose

To investigate the relationships between Wnt1 inducible signaling pathway protein 1 (WISP1) polymorphisms and the prognosis of platinum-based chemotherapy in lung cancer patients.

Patients and Methods

A total of 363 lung cancer patients were recruited in this study. All of them received at least two cycles of platinum-based chemotherapy. We used unconditional logistic regression analysis to assess the associations of 39 single nucleotide polymorphisms in WISP1 gene with platinum-based chemotherapy prognosis.

Results

The results indicated that patients carried rs2929973 GT or GG genotypes had increased risk of disease progression (HR = 0.712, 95% CI = 0.553–0.916, P = 0.015). Patients with rs2977551 TT genotype had a significantly decreased risk of progression-free survival than patients carrying CT or CC genotype (HR = 0.723, 95% CI = 0.561–0.932, P = 0.032) and overall survival (HR = 0.725, 95% CI = 0.552–0.913, P = 0.045). For rs2977549, patients carrying TT genotype had a significantly longer progression-free survival than patients with CC or CT genotypes (HR = 0.708, 95% CI = 0.550–0.912, P = 0.017). Among of them, rs16904853, rs10956697, rs2929965, rs2929973, rs7828685, rs2977551 and rs2977549 were related to progression-free survival, and rs10956697 and rs2977551 were related to overall survival in subgroup analyses, respectively.

Conclusion

WISP1 rs2929973, rs2977551 and rs2977549 may be contributed to a potential candidate biomarker for prediction of platinum-based chemotherapy prognosis in lung cancer patients.

WISP-1 induced by mechanical stress contributes to fibrosis and hypertrophy of the ligamentum flavum through Hedgehog-Gli1 signaling

Ongoing chronic fibrosis and hypertrophy of the ligamentum flavum (LF) is an important cause of lumbar spinal canal stenosis (LSCS). Our previous work showed that WNT1-inducible signaling pathway protein 1 (WISP-1) is a critical driver of LF fibrosis. However, the potential mechanism has not been explored. Here, we found that Gli1 was upregulated in hypertrophic LF tissues and required for fibrogenesis in fibroblasts. Moreover, mechanical stretching increased the expression of WISP-1 in LF fibroblasts. Furthermore, WISP-1 induced fibrogenesis in vitro through the Hedgehog-Gli1 pathway. This conclusion was supported by the fact that WISP-1 activated the Hedgehog-Gli1 pathway in LF fibroblasts and that cyclopamine attenuated the effect of WISP-1-induced fibrogenesis. WISP-1 also promoted the transition of fibroblasts into myofibroblasts via the Hedgehog pathway. Importantly, a hypertrophic LF rabbit model induced by mechanical stress also showed pathological changes in fibrosis and elevated expression of WISP-1, Gli1, and α-SMA. Therapeutic administration of cyclopamine reduced collagen expression, fibroblast proliferation, and myofibroblast differentiation and ameliorated fibrosis in the mechanical stress-induced rabbit model. Collectively, our findings show mechanical stress/WISP-1/Hedgehog signaling as a new fibrotic axis contributing to LF hypertrophy and identify Hedgehog signaling as a therapeutic target for the prevention and treatment of LF fibrosis.

COPD-associated miR-145-5p is downregulated in early-decline FEV1 trajectories in childhood asthma

BACKGROUND

Many microRNAs (miRNAs) have been associated with asthma and chronic obstructive pulmonary disease (COPD). Longitudinal lung function growth trajectories of children with asthma-normal growth, reduced growth (RG), early decline (ED), and RG with an ED (RGED)-have been observed, with RG and RGED associated with adverse outcomes, including COPD.

OBJECTIVE

Our aim was to determine whether circulating miRNAs from an early age in children with asthma would be prognostic of reduced lung function growth patterns over the next 16 years.

METHODS

We performed small RNA sequencing on sera from 492 children aged 5 to 12 years with mild-to-moderate asthma from the CAMP clinical trial, who were subsequently followed for 12 to 16 years. miRNAs were assessed for differential expression between previously assigned lung function growth patterns.

RESULTS

We had 448 samples and 259 miRNAs for differential analysis. In a comparison of the normal and the most severe group (ie, normal growth compared with RGED), we found 1 strongly dysregulated miRNA, hsa-miR-145-5p (P < 8.01E-05). This miR was downregulated in both ED groups (ie, ED and RGED). We verified that miR-145-5p was strongly associated with airway smooth muscle cell growth in vitro.

CONCLUSION

Our results showed that miR-145-5p is associated with the ED patterns of lung function growth leading to COPD in children with asthma and additionally increases airway smooth muscle cell proliferation. This represents a significant extension of our understanding of the role of miR-145-5p in COPD and suggests that reduced expression of miR-145-5p is a risk factor for ED of long-term lung function.

Genome-wide association study of asthma exacerbations despite inhaled corticosteroid use

RATIONALE

Substantial variability in response to asthma treatment with inhaled corticosteroids (ICS) has been described among individuals and populations, suggesting the contribution of genetic factors. Nonetheless, only a few genes have been identified to date. We aimed to identify genetic variants associated with asthma exacerbations despite ICS use in European children and young adults and to validate the findings in non-Europeans. Moreover, we explored whether a gene-set enrichment analysis could suggest potential novel asthma therapies.

METHODS

A genome-wide association study (GWAS) of asthma exacerbations was tested in 2681 children of European descent treated with ICS from eight studies. Suggestive association signals were followed up for replication in 538 European asthma patients. Further evaluation was performed in 1773 non-Europeans. Variants revealed by published GWAS were assessed for replication. Additionally, gene-set enrichment analysis focused on drugs was performed.

RESULTS

10 independent variants were associated with asthma exacerbations despite ICS treatment in the discovery phase (p≤5×10-6). Of those, one variant at the CACNA2D3-WNT5A locus was nominally replicated in Europeans (rs67026078; p=0.010), but this was not validated in non-European populations. Five other genes associated with ICS response in previous studies were replicated. Additionally, an enrichment of associations in genes regulated by trichostatin A treatment was found.

CONCLUSIONS

The intergenic region of CACNA2D3 and WNT5A was revealed as a novel locus for asthma exacerbations despite ICS treatment in European populations. Genes associated were related to trichostatin A, suggesting that this drug could regulate the molecular mechanisms involved in treatment response.

Circulating MicroRNA: Incident Asthma Prediction and Vitamin D Effect Modification

Of children with recurrent wheezing in early childhood, approximately half go on to develop asthma. MicroRNAs have been described as excellent non-invasive biomarkers due to their prognostic utility. We hypothesized that circulating microRNAs can predict incident asthma and that that prediction might be modified by vitamin D. We selected 75 participants with recurrent wheezing at 3 years old from the Vitamin D Antenatal Asthma Reduction Trial (VDAART). Plasma samples were collected at age 3 and sequenced for small RNA-Seq. The read counts were normalized and filtered by depth and coverage. Logistic regression was employed to associate miRNAs at age 3 with asthma status at age 5. While the overall effect of miRNA on asthma occurrence was weak, we identified 38 miRNAs with a significant interaction effect with vitamin D and 32 miRNAs with a significant main effect in the high vitamin D treatment group in VDAART. We validated the VDAART results in Project Viva for both the main effect and interaction effect. Meta-analysis was performed on both cohorts to obtain the combined effect and a logistic regression model was used to predict incident asthma at age 7 in Project Viva. Of the 23 overlapped miRNAs in the stratified and interaction analysis above, 9 miRNAs were replicated in Project Viva with strong effect size and remained in the meta-analysis of the two populations. The target genes of the 9 miRNAs were enriched for asthma-related Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathways. Using logistic regression, microRNA hsa-miR-574-5p had a good prognostic ability for incident asthma prognosis with an area under the receiver operating characteristic (AUROC) of 0.83. In conclusion, miRNAs appear to be good biomarkers of incident asthma, but only when vitamin D level is considered.

Wnt Signaling Is Deranged in Asthmatic Bronchial Epithelium and Fibroblasts

Both canonical and non-canonical Wnt signaling pathway alterations have been documented in pulmonary disease pathogenesis and progression; therefore, they can be an attractive target for pharmaceutical management of severe asthma. Wnt/β-catenin signaling was shown to link early embryonic lung development impairment to later in life asthmatic airway remodeling. Here we explored the changes in Wnt signaling associated with asthma initiation and progression in epithelial and fibroblasts using a comprehensive approach based on in silico analysis and followed by in vitro validation. In summary, the in silico analysis showed that the bronchial epithelium of severe asthmatic patients showed a deranged balance between Wnt enhancer and Wnt inhibitors. A Th2-high phenotype is associated with upregulated Wnt-negative regulators, while inflammatory and neutrophilic severe asthmatics showed higher canonical Wnt signaling member enrichment. Most of these genes are regulators of healthy lung development early in life and, if disturbed, can make people susceptible to developing asthma early in life and prone to developing a severe phenotype. Most of the Wnt members are secreted, and their effect can be in an autocrine fashion on the bronchial epithelium, paracrine on nearby adjacent structural cells like fibroblasts and smooth muscles, or systemic in blood. Our results showed that canonical Wnt signaling is needed for the proper response of cells to proliferative stimuli, which puts cells under stress. Cells in response to this proliferative stress will activate the senescence mechanism, which is also dependent on Wnt signaling. Inhibition of Wnt signaling using FH535 inhibits both proliferation and senescence markers in bronchial fibroblasts compared to DMSO-treated cells. In fibroblasts from asthmatic patients, inhibition of Wnt signaling did not show that effect as the Wnt signaling is deranged besides other pathways that might be non-functional.

Cross-talk of Signaling Pathways in the Pathogenesis of Allergic Asthma and Cataract

Allergic asthma is a chronic inflammatory disease, which involves many cellular and cellular components. Cataract is a condition that affects the transparency of the lens, which the opacity of the lens caused by any innate or acquired factor degrades its transparency or changes in color. Both of them belong to diseases induced by immune disorders or inflammation. We want to confirm the signaling pathways involved in the regulation of asthma and cataract simultaneously, and provide reference for the later related experiments. So we conducted a scoping review of many databases and searched for studies (Academic research published in Wiley, Springer and Bentham from 2000 to 2019) about the possible relationship between asthma and cataract. It was found that during the onset of asthma and cataract, Rho/Rock signaling pathway, Notch signaling pathway, Wnt/β-catenin signaling pathway, PI3K/AKT signaling pathway, JAK/STAT signaling pathway, MAPK signaling pathway, TGF-β1/Smad signaling pathway and NF-κB signaling pathway are all active, so they may have a certain correlation in pathogenesis. Asthma may be associated with cataract through the eight signaling pathways, causing inflammation or immune imbalance based on allergy that can lead to cataract. According to these studies, we speculated that the three most likely signaling pathways are PI3K/AKT, MAPK and NF-κB signaling pathway.

WNT Signalling in Lung Physiology and Pathology

The main physiological function of the lung is gas exchange, mediated at the interface between the alveoli and the pulmonary microcapillary network and facilitated by conducting airway structures that regulate the transport of these gases from and to the alveoli. Exposure to microbial and environmental factors such as allergens, viruses, air pollution, and smoke contributes to the development of chronic lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and lung cancer. Respiratory diseases as a cluster are the commonest cause of chronic disease and of hospitalization in children and are among the three most common causes of morbidity and mortality in the adult population worldwide. Many of these chronic respiratory diseases are associated with inflammation and structural remodelling of the airways and/or alveolar tissues. They can often only be treated symptomatically with no disease-modifying therapies that normalize the pathological tissue destruction driven by inflammation and remodelling. In search for novel therapeutic strategies for these diseases, several lines of evidence revealed the WNT pathway as an emerging target for regenerative strategies in the lung. WNT proteins, their receptors, and signalling effectors have central regulatory roles under (patho)physiological conditions underpinning lung function and (chronic) lung diseases and we summarize these roles and discuss how pharmacological targeting of the WNT pathway may be utilized for the treatment of chronic lung diseases.

Effect of Intrauterine Smoke Exposure on microRNA-15a Expression in Human Lung Development and Subsequent Asthma Risk

Background: In utero smoke (IUS) exposure is associated with asthma susceptibility. Objective: We sought to test the hypothesis that changes in miRNA expression by IUS exposure during human lung development is associated with asthma susceptibility. Methods: Gene expression was profiled from 53 IUS unexposed and 51 IUS exposed human fetal lung tissues. We tested for the differential expression of miRNAs across post-conception age and by IUS using linear models with covariate adjustment. We tested the IUS-associated miRNAs for association with their gene expression targets using pair-wise inverse correlation. Using our mouse model, we investigated the persistence of the IUS-associated miRNA signature using RT-PCR from the lungs of mouse pups with and without IUS at postnatal day 14. MiRNAs were then tested for association with asthma and exacerbations using whole blood gene expression profiles from Asthma BRIDGE. Results: Five miRNAs were differentially expressed across post-conception age (adjusted p < 0.0002) including two that were differentially expressed by IUS exposure in human fetal lung (p < 0.05). MiR-15a was differentially expressed by post-conception age (p = 0.00002), IUS exposure in human fetal lung (p = 0.005), and in the post-natal mouse lung (p = 0.01). MiR-15a was also associated with the in utero expression of GSDMB (adjusted p = 0.0002), a known childhood asthma gene and with asthma exacerbations (p = 0.0009) in Asthma BRIDGE. Thus, miR-15a is expressed during human lung development, is impacted by IUS exposure, regulates the intrauterine expression of asthma genes, and is associated with asthma severity. Conclusions: These results provide evidence for the role of miR-15a in the fetal origin of asthma.

Emerging role of CCN family proteins in fibrosis

Fibrosis is a common pathological change characterized by the excessive accumulation of fibrous connective tissue. Once uncontrolled, this pathological progress can lead to irreversible damage to the structure and function of organs, which is a serious threat to human health and life. Actually, the disability and death of patients caused by many chronic diseases have a closed relationship with fibrosis. The CCN protein family, including six members, is a small group of matrix proteins exhibiting structurally similar features. In the past 20 years, different biological functions of CCN proteins have been identified in various diseases. Of note, it has been recently shown that they are implicated in the key pathological process of fibrosis. In this review, we summarize the current status of knowledge regarding the role of CCN proteins involved in the pathogenesis of fibrosis diseases in detail. Furthermore, we highlight some of the underlying interaction mechanisms of CCN protein acting in fibrosis that helps to develop new drugs and determine appropriate clinical strategies for fibrotic diseases.

Co-methylation analysis in lung tissue identifies pathways for fetal origins of COPD

COPD likely has developmental origins; however, the underlying molecular mechanisms are not fully identified. Investigation of lung tissue-specific epigenetic modifications such as DNA methylation using network approaches might facilitate insights linking in utero smoke (IUS) exposure and risk for COPD in adulthood.We performed genome-wide methylation profiling for adult lung DNA from 160 surgical samples and 78 fetal lung DNA samples isolated from discarded tissue at 8-18 weeks of gestation. Co-methylation networks were constructed to identify preserved modules that shared methylation patterns in fetal and adult lung tissues and associations with fetal IUS exposure, gestational age and COPD.Weighted correlation networks highlighted preserved and co-methylated modules for both fetal and adult lung data associated with fetal IUS exposure, COPD and lower adult lung function. These modules were significantly enriched for genes involved in embryonic organ development and specific inflammation-related pathways, including Hippo, phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT), Wnt, mitogen-activated protein kinase and transforming growth factor-β signalling. Gestational age-associated modules were remarkably preserved for COPD and lung function, and were also annotated to genes enriched for the Wnt and PI3K/AKT pathways.Epigenetic network perturbations in fetal lung tissue exposed to IUS and of early lung development recapitulated in adult lung tissue from ex-smokers with COPD. Overlapping fetal and adult lung tissue network modules highlighted putative disease pathways supportive of exposure-related and age-associated developmental origins of COPD.

Association of circadian clock TIMELESS variants and expression with asthma risk in children

INTRODUCTION

Bronchial asthma is a chronic respiratory disease characterized by airway inflammation, allergen-induced hypersensitivity and dyspnea. Most asthmatic patients demonstrate oscillations of disease symptoms within 24 hours regulated by circadian clock genes. We hypothesized that these genes may be regulators of childhood asthma risk.

OBJECTIVES

The aim was to investigate whether single-nucleotide polymorphisms (SNPs) in the circadian clock genes are associated with childhood asthma risk. We also aimed to analyze the mRNA level of clock genes in the blood of asthmatic children and NHBE cells stimulated with IL-13.

MATERIALS AND METHODS

Peripheral blood was collected from 165 asthmatic and 138 healthy Polish children. NHBE cells were culture at the air-liquid interface (ALI) with IL-13 as an in vitro model of allergic inflammation. Using TaqMan probes, we genotyped 32 SNPs in: CLOCK, BMAL1, PER3 and TIMELESS. Expression analysis for TIMELESS was performed using real-time PCR with SYBR Green. For haplotype and genotype statistical analysis we used Haploview 4.2 and STATISTICA version 12, respectively. Gene expression analysis was performed in DataAssist v3.01.

RESULTS

We found that three polymorphisms in TIMELESS (rs2291739, rs10876890, rs11171856) and two haplotypes (TTTT and CTAC) were associated with asthma risk. We also found significantly decreased expression of TIMELESS in the blood of asthmatic children as compared to the healthy children (P = 0.0289) and in NHBE cells stimulated with IL-13 (P = 0.0302).

CONCLUSIONS

In our study, we showed for the first time that TIMELESS variants and expression may be associated with childhood asthma.

[Obesity and asthma: Mechanisms and therapeutic options]

Asthma and obesity are both common conditions, which lead to a substantial public health burden. The obese-asthma phenotype is characterized by poor asthma control, impaired lung function and decreased efficacy of inhaled treatment. However, this phenotype is highly heterogeneous and involves numerous mechanisms, including systemic inflammation and adipokines. A role for microbiota modifications and genetics has been suggested. Obese-asthma patient management currently consists in weight loss and usual anti-asthmatic treatment. New therapeutic options are being evaluated.

In utero exposure to cigarette smoke and effects across generations: A conference of animals on asthma

BACKGROUND

The prevalence of asthma and chronic obstructive pulmonary disease (COPD) has risen markedly over the last decades and is reaching epidemic proportions. However, underlying molecular mechanisms are not fully understood, hampering the urgently needed development of approaches to prevent these diseases. It is well established from epidemiological studies that prenatal exposure to cigarette smoke is one of the main risk factors for aberrant lung function development or reduced fetal growth, but also for the development of asthma and possibly COPD later in life. Of note, recent evidence suggests that the disease risk can be transferred across generations, that is, from grandparents to their grandchildren. While initial studies in mouse models on in utero smoke exposure have provided important mechanistic insights, there are still knowledge gaps that need to be filled.

OBJECTIVE

Thus, in this review, we summarize current knowledge on this topic derived from mouse models, while also introducing two other relevant animal models: the fruit fly Drosophila melanogaster and the zebrafish Danio rerio.

METHODS

This review is based on an intensive review of PubMed-listed transgenerational animal studies from 1902 to 2018 and focuses in detail on selected literature due to space limitations.

RESULTS

This review gives a comprehensive overview of mechanistic insights obtained in studies with the three species, while highlighting the remaining knowledge gaps. We will further discuss potential (dis)advantages of all three animal models.

CONCLUSION/CLINICAL RELEVANCE

Many studies have already addressed transgenerational inheritance of disease risk in mouse, zebrafish or fly models. We here propose a novel strategy for how these three model organisms can be synergistically combined to achieve a more detailed understanding of in utero cigarette smoke-induced transgenerational inheritance of disease risk.

Wnt-3a Induces Cytokine Release in Human Mast Cells

Mast cells are well known for their detrimental effects in allergies and asthma, and Wnt signaling has recently been implicated in asthma and other airway diseases. However, it is not known if or how Wnts affect human mast cells. Since Wnt expression is elevated in individuals with asthma and is linked to a Th2 profile, we hypothesized that mast cells could be affected by Wnts in the context of asthma. We therefore sought to investigate the role of Wnt signaling in human mast cell development and activation. We first examined the expression of the 10 main Wnt receptors, Frizzled 1–10 (FZD_1–10), and found expression of several FZDs in human mast cells. Treatment with purified recombinant Wnt-3a or Wnt-5a did not affect the proliferation or maturation of CD34⁺ progenitors into mast cells, as indicated by cellular expression of CD117 and FcεRI, activation by FcεRI crosslinking, and histamine and tryptase release. Furthermore, Wnt treatment did not change the phenotype from MC_T to MC_TC, since MrgX2 expression, compound 48/80-mediated activation, and carboxypeptidase A3 content were not affected. However, Wnt-3a activated WNT/β-catenin signaling in mature human mast cells, as revealed by stabilization of β-catenin, upregulation of IL-8 and CCL8 mRNA expression, and release of IL-8 protein. Thus, our data suggest that Wnt-3a activation of mast cells could contribute to the recruitment of immune cells in conditions associated with increased Wnt-3a expression, such as asthma.

Prenatal particulate matter affects new asthma via airway hyperresponsiveness in schoolchildren

BACKGROUND

The most relevant time of PM₁₀ exposure to affect airway hyperresponsiveness (AHR) and new development of asthma in school-aged children is unclear. The aims of this study were to investigate the most critical time of PM₁₀ exposure to affect AHR and new diagnosis of asthma from AHR in school-aged children.

METHODS

Elementary schoolchildren (n = 3570) have been enrolled in a nationwide prospective 4-year follow-up survey in Korea from 2005 to 2006. Individual annual PM₁₀ exposure was estimated by using an ordinary kriging method from the prenatal period to 7 years of age. AHR at 7 years was defined by a methacholine PC₂₀ ≤8 mg/mL.

RESULTS

PM₁₀ exposure during pregnancy and at 1 year of age showed significant effects on AHR (aOR: 1.694, 95% CI: 1.298-2.209; and aOR: 1.750, 95% CI: 1.343-2.282, respectively). PM₁₀ exposure during pregnancy was associated with the risk of a new diagnosis of asthma (aOR: 2.056, 95% CI: 1.240-3.409), with the highest risk in children with AHR at age 7 (aOR: 6.080, 95% CI: 2.150-17.195). PM₁₀ exposure in the second trimester was associated with the highest risk of a new diagnosis of asthma in children with AHR at age 7 (aOR: 4.136, 95% CI: 1.657-10.326).

CONCLUSIONS

Prenatal PM₁₀ exposure in the second trimester is associated with an increased risk of a new diagnosis of asthma in school-aged children with AHR at 7 years. This study suggests that PM₁₀ exposure during a specific trimester in utero may affect the onset of childhood asthma via AHR.

Vitamin D alleviates airway remodeling in asthma by down-regulating the activity of Wnt/β-catenin signaling pathway

Vitamin D exerts a protective role in asthma; however, the molecular mechanisms underlying the vitamin D-attenuated asthma airway remodeling are yet to be elucidated. In this study, Sprague-Dawley (SD) rats were randomly divided into four groups: control, asthma, vitamin D 50 ng/mL, and vitamin D 100 ng/mL. The treatment with 100 ng/mL vitamin D remarkably reduced the thickness of the airway smooth muscle, collagen deposition, and the alpha-smooth muscle actin (α-SMA) mass and airway inflammation. Conversely, the treatment by vitamin D significantly up-regulated the serum levels of 25(OH)₂D₃ that were decreased in asthma. The putative signaling pathway of vitamin D was based on Wnt5a and β-catenin expression assessed by quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) and Western blot, which revealed that the administration of vitamin D significantly decreased the activity of Wnt/β-catenin signaling pathway. These results suggested that administration of vitamin D alleviated the airway remodeling in asthma by down-regulating the activity of Wnt/β-catenin signaling pathway.

Impacts of WNT1-inducible signaling pathway protein 1 polymorphism on hepatocellular carcinoma development

BACKGROUND

WNT1-inducible signaling pathway protein 1 (WISP1) is a member of CCN protein family and a downstream target of β-catenin. Aberrant WISP1 expression is associated with carcinogenesis. In the current study, we focused on examining WISP1 single nucleotide polymorphisms (SNPs) to elucidate hepatocellular carcinoma (HCC) clinicopathologic characteristics.

METHODOLOGY/PRINCIPAL FINDINGS

The WISP1 SNPs rs2977530, rs2977537, rs2929973, rs2929970, rs62514004, and rs16893344 were analyzed by real-time polymerase chain reaction in 332 patients with HCC and 664 cancer-free controls.

RESULTS

The patients with higher frequencies of WISP1 rs62514004 (AG + GG) and rs16893344 (CT + TT) variants revealed a lower risk to reach a later clinical stage compared with their wild-type carriers. Furthermore, individuals who carried WISP1 rs62514004 and rs16893344 haplotype G-T showed a greater synergistic effect combined with alcohol drinking on HCC development (AOR = 26.590, 95% CI = 9.780-72.295).

CONCLUSIONS

Our results demonstrated that the HCC patients with WISP1 SNPs are associated with HCC development, and WISP1 SNPs may serve as markers or therapeutic targets for HCC.

miR-142-3p is associated with aberrant WNT signaling during airway remodeling in asthma

Asthma is characterized by a chronic inflammation and remodeling of the airways. Although inflammation can be controlled, therapeutic options to revert remodeling do not exist. Thus, there is a large and unmet need to understand the underlying molecular mechanisms to develop novel therapies. We previously identified a pivotal role for miR-142-3p in regulating airway smooth muscle (ASM) precursor cell proliferation during lung development by fine-tuning the Wingless/Integrase I (WNT) signaling. Thus, we here aimed to investigate the relevance of this interaction in asthma. We performed quantitative RT-PCR and immune staining in a murine model for ovalbumin-induced allergic airway inflammation and in bronchial biopsies from patients with asthma and isolated primary fibroblasts thereof. miR-142-3p was increased in hyperproliferative regions of lung in murine and human asthma, whereas this microRNA (miRNA) was excluded from regions with differentiated ASM cells. Increases in miR-142-3p were associated with a decrease of its known target Adenomatous polyposis coli. Furthermore, we observed a differential expression of miR-142-3p in bronchial biopsies from patients with early or late onset severe asthma, which coincided with a differential WNT signature. Our data suggest that miR-142-3p is involved in regulating the balance between proliferation and differentiation of ASM cells in asthma, possibly via controlling WNT signaling. Thus, this miRNA might be an interesting target to prevent ASM hyperproliferation in asthma.

Association of genetic variations in the Wnt signaling pathway genes with myocardial infarction susceptibility in Chinese Han population

Numerous studies have implicated the Wnt pathway in the development and progression of myocardial infarction (MI); however, there are very few investigations addressing the effects of polymorphisms in the Wnt pathway genes on MI susceptibility. We investigated the possible correlation between genetic variations in Wnt pathway genes and MI risk. Three polymorphisms (rs7832767 C > T in SFRP1 gene, rs2293303 C > T in CTNNB1 gene, rs16893344 C > T in WISP1 gene) were finally selected and genotyped in 465 MI patients and 485 healthy controls, using the PCR-RFLP method. We found that the SFRP1 rs7832767 variant allele (T) was associated with a significantly increased risk of MI [TT vs. CC: adjusted odds ratio (AOR) = 3.13, 95% CI = 1.78-5.51; CT/TT vs. CC: AOR = 1.53, 95% CI = 1.12-2.08; TT vs. CC/CT: AOR = 2.87, 95% CI = 1.66-4.97)]. The significant association with MI risk was also found for the CTNNB1 rs2293303 (CT vs. CC: AOR = 3.48, 95% CI = 2.28-5.33; TT vs. CC: AOR = 7.37, 95% CI = 2.08-26.16; CT/TT vs. CC: AOR = 3.72, 95% CI = 2.46-5.62; TT vs. CC/CT: AOR = 5.52, 95% CI = 1.58-19.28), and WISP1 rs16893344 polymorphisms (CT vs. CC: AOR = 2.43, 95% CI = 1.70-3.47; TT vs. CC: AOR = 5.17, 95% CI = 1.85-14.41; CT/TT vs. CC: AOR = 2.58, 95% CI = 1.83-3.66; TT vs. CC/CT: AOR = 3.88, 95% CI = 1.41-10.64). The associations remain significant in stratified analysis by demographic and clinical characteristics of participants, with few exceptions. Our study provided the first evidence of the association between polymorphisms in the Wnt pathway genes and MI susceptibility in Chinese Han population. Epidemiological studies with larger samples and functional analyses are warranted to further verify our results.

WISP1 genetic variants as predictors of tumor development with urothelial cell carcinoma

OBJECTIVES

Urothelial cell carcinoma (UCC) of the urinary bladder is a major malignancy of the genitourinary tract. Etiological factors, such as the environment, ethnicity, genetics, and diet, contribute to UCC carcinogenesis. WNT1-inducible signaling pathway protein 1 (WISP1), also known as CCN4, a cysteine-rich protein belonging to the Cyr61, CTGF, Nov (CCN) family of matricellular proteins, has many developmental functions and might be involved in carcinogenesis. This study investigated WISP1 single-nucleotide polymorphisms to evaluate UCC susceptibility and clinicopathological characteristics.

MATERIALS AND METHODS

Real-time polymerase chain reaction was used to analyze 4 single-nucleotide polymorphisms of WISP1 in 369 patients with UCC and 738 controls without cancer.

RESULTS

The results showed that in 128 women with UCC who carried WISP1 rs2929973 (AG + GG) variants had a higher risk of developing an advanced muscle-invasive tumor stage (pT2-pT4, P = 0.007) and a large tumor (T1-T4, P = 0.030). Further analyses revealed that a correlation between the expressions of WISP1 and invasive tumor and large tumor size in urothelial carcinoma was observed in the TCGA (The Cancer Genome Atlas) dataset.

CONCLUSIONS

Our results indicated that patients with UCC carrying rs2977530 genetic variants (AG + GG) have a higher risk of developing a more invasive tumor stage and a large tumor. WISP1 polymorphisms may serve as a marker or a therapeutic target in UCC.

Lung development, regeneration and plasticity: From disease physiopathology to drug design using induced pluripotent stem cells

Lungs have a complex structure composed of different cell types that form approximately 17 million airway branches of gas-delivering bronchioles connected to 500 million gas-exchanging alveoli. Airways and alveoli are lined by epithelial cells that display a low rate of turnover at steady-state, but can regenerate the epithelium in response to injuries. Here, we review the key points of lung development, homeostasis and epithelial cell plasticity in response to injury and disease, because this knowledge is required to develop new lung disease treatments. Of note, canonical signaling pathways that are essential for proper lung development during embryogenesis are also involved in the pathophysiology of most chronic airway diseases. Moreover, the perfect control of these interconnected pathways is needed for the successful differentiation of induced pluripotent stem cells (iPSC) into lung cells. Indeed, differentiation of iPSC into airway epithelium and alveoli is based on the use of biomimetics of normal embryonic and fetal lung development. In vitro iPSC-based models of lung diseases can help us to better understand the impaired lung repair capacity and to identify new therapeutic targets and new approaches, such as lung cell therapy.

Revisiting asthma therapeutics: focus on WNT signal transduction

Asthma is a complex disease of the airways that develops as a consequence of both genetic and environmental factors. This interaction has highlighted genes important in early life, particularly those that control lung development, such as the Wingless/Integrase-1 (WNT) signalling pathway. Although aberrant WNT signalling is involved with an array of human conditions, it has received little attention within the context of asthma. Yet it is highly relevant, driving events involved with inflammation, airway remodelling, and airway hyper-responsiveness (AHR). In this review, we revisit asthma therapeutics by examining whether WNT signalling is a valid therapeutic target for asthma.

Wnt/β-catenin signaling links embryonic lung development and asthmatic airway remodeling

Embryonic lung development requires reciprocal endodermal-mesodermal interactions; mediated by various signaling proteins. Wnt/β-catenin is a signaling protein that exhibits the pivotal role in lung development, injury and repair while aberrant expression of Wnt/β-catenin signaling leads to asthmatic airway remodeling: characterized by hyperplasia and hypertrophy of airway smooth muscle cells, alveolar and vascular damage goblet cells metaplasia, and deposition of extracellular matrix; resulting in decreased lung compliance and increased airway resistance. The substantial evidence suggests that Wnt/β-catenin signaling links embryonic lung development and asthmatic airway remodeling. Here, we summarized the recent advances related to the mechanistic role of Wnt/β-catenin signaling in lung development, consequences of aberrant expression or deletion of Wnt/β-catenin signaling in expansion and progression of asthmatic airway remodeling, and linking early-impaired pulmonary development and airway remodeling later in life. Finally, we emphasized all possible recent potential therapeutic significance and future prospectives, that are adaptable for therapeutic intervention to treat asthmatic airway remodeling.

Mitigation of sepsis-induced inflammatory responses and organ injury through targeting Wnt/β-catenin signaling

The Wnt/β-catenin pathway has been involved in regulating inflammation in various infectious and inflammatory diseases. Sepsis is a life-threatening condition caused by dysregulated inflammatory response to infection with no effective therapy available. Recently elevated Wnt/β-catenin signaling has been detected in sepsis. However, its contribution to sepsis-associated inflammatory response remains to be explored. In this study, we show that inhibition of Wnt/β-catenin signaling reduces inflammation and mitigates sepsis-induced organ injury. Using in vitro LPS-stimulated RAW264.7 macrophages, we demonstrate that a small-molecule inhibitor of β-catenin responsive transcription, iCRT3, significantly reduces the LPS-induced Wnt/β-catenin activity and also inhibits TNF-α production and IκB degradation in a dose-dependent manner. Intraperitoneal administration of iCRT3 to C57BL/6 mice, subjected to cecal ligation and puncture-induced sepsis, decreases the plasma levels of proinflammatory cytokines and organ injury markers in a dose-dependent manner. The histological integrity of the lungs is improved with iCRT3 treatment, along with reduced lung collagen deposition and apoptosis. In addition, iCRT3 treatment also decreases the expression of the cytokines, neutrophil chemoattractants, as well as the MPO activity in the lungs of septic mice. Based on these findings we conclude that targeting the Wnt/β-Catenin pathway may provide a potential therapeutic approach for treatment of sepsis.

Genetics and Genomics of Longitudinal Lung Function Patterns in Individuals with Asthma

RATIONALE

Patterns of longitudinal lung function growth and decline in childhood asthma have been shown to be important in determining risk for future respiratory ailments including chronic airway obstruction and chronic obstructive pulmonary disease.

OBJECTIVES

To determine the genetic underpinnings of lung function patterns in subjects with childhood asthma.

METHODS

We performed a genome-wide association study of 581 non-Hispanic white individuals with asthma that were previously classified by patterns of lung function growth and decline (normal growth, normal growth with early decline, reduced growth, and reduced growth with early decline). The strongest association was also measured in two additional cohorts: a small asthma cohort and a large chronic obstructive pulmonary disease metaanalysis cohort. Interaction between the genomic region encompassing the most strongly associated single-nucleotide polymorphism and nearby genes was assessed by two chromosome conformation capture assays.

MEASUREMENTS AND MAIN RESULTS

An intergenic single-nucleotide polymorphism (rs4445257) on chromosome 8 was strongly associated with the normal growth with early decline pattern compared with all other pattern groups (P = 6.7 × 10^-9; odds ratio, 2.8; 95% confidence interval, 2.0-4.0); replication analysis suggested this variant had opposite effects in normal growth with early decline and reduced growth with early decline pattern groups. Chromosome conformation capture experiments indicated a chromatin interaction between rs4445257 and the promoter of the distal CSMD3 gene.

CONCLUSIONS

Early decline in lung function after normal growth is associated with a genetic polymorphism that may also protect against early decline in reduced growth groups. Clinical trial registered with www.clinicaltrials.gov (NCT00000575).

Sex-Based Genetic Association Study Identifies CELSR1 as a Possible Chronic Obstructive Pulmonary Disease Risk Locus among Women

Chronic obstructive pulmonary disease (COPD) is a complex disease with strong environmental and genetic influences and sexually dimorphic features. Although genetic risk factors for COPD have been identified, much of the heritability remains unexplained. Sex-based genetic association studies may uncover additional COPD genetic risk factors. We studied current and former smokers from COPD case-control cohorts (COPDGene non-Hispanic whites and African Americans, Evaluation of COPD Longitudinally to Identify Predictive Surrogate End-Points, and Genetics of Chronic Obstructive Lung Disease). COPD was defined as post-bronchodilator forced expiratory volume in 1 second/forced vital capacity less than 0.70 and forced expiratory volume in 1 second percent predicted less than 80. Testing was performed across all cohorts and combined in a meta-analysis adjusted for age, pack-years, and genetic ancestry. We first performed genome-wide single-nucleotide polymorphism (SNP)-by-sex interaction testing on the outcome of COPD affection status. We performed sex-stratified association testing for SNPs with interaction P less than 10^-6. We examined over 8 million SNPs in four populations, including 6,260 subjects with COPD (40.6% female) and 5,269 smoking control subjects (47.3% female). The SNP rs9615358 in the cadherin gene CELSR1 approached genome-wide significance for an interaction with sex (P = 1.24 × 10^-7). In the sex-stratified meta-analysis, this SNP was associated with COPD among females (odds ratio, 1.37 [95% confidence interval, 1.25-1.49]; P = 3.32 × 10^-7) but not males (odds ratio, 0.90 [95% confidence interval, 0.79-1.01]; P = 0.06). CELSR1 is involved in fetal lung development. In a human fetal lung tissue dataset, we observed greater CELSR1 expression in female compared with male samples. This SNP-by-sex genome-wide association analysis identified the fetal lung development gene, CELSR1, as a potential sex-specific risk factor for COPD. Identifying sex-specific genetic risk factors may reveal new insights into sexually dimorphic features of COPD.

Susceptibility to Childhood Pneumonia: A Genome-Wide Analysis

Previous studies have indicated that in adult smokers, a history of childhood pneumonia is associated with reduced lung function and chronic obstructive pulmonary disease. There have been few previous investigations using genome-wide association studies to investigate genetic predisposition to pneumonia. This study aims to identify the genetic variants associated with the development of pneumonia during childhood and over the course of the lifetime. Study subjects included current and former smokers with and without chronic obstructive pulmonary disease participating in the COPDGene Study. Pneumonia was defined by subject self-report, with childhood pneumonia categorized as having the first episode at <16 years. Genome-wide association studies for childhood pneumonia (843 cases, 9,091 control subjects) and lifetime pneumonia (3,766 cases, 5,659 control subjects) were performed separately in non-Hispanic whites and African Americans. Non-Hispanic white and African American populations were combined in the meta-analysis. Top genetic variants from childhood pneumonia were assessed in network analysis. No single-nucleotide polymorphisms reached genome-wide significance, although we identified potential regions of interest. In the childhood pneumonia analysis, this included variants in NGR1 (P = 6.3 × 10^-8), PAK6 (P = 3.3 × 10^-7), and near MATN1 (P = 2.8 × 10^-7). In the lifetime pneumonia analysis, this included variants in LOC339862 (P = 8.7 × 10^-7), RAPGEF2 (P = 8.4 × 10^-7), PHACTR1 (P = 6.1 × 10^-7), near PRR27 (P = 4.3 × 10^-7), and near MCPH1 (P = 2.7 × 10^-7). Network analysis of the genes associated with childhood pneumonia included top networks related to development, blood vessel morphogenesis, muscle contraction, WNT signaling, DNA damage, apoptosis, inflammation, and immune response (P ≤ 0.05). We have identified genes potentially associated with the risk of pneumonia. Further research will be required to confirm these associations and to determine biological mechanisms.

CLINICAL TRIAL REGISTRATION

NCT00608764.

Age, Sexual Dimorphism, and Disease Associations in the Developing Human Fetal Lung Transcriptome

The fetal origins of disease hypothesis suggests that variations in the course of prenatal lung development may affect life-long pulmonary function growth, decline, and pathobiology. Many studies support the existence of differences in the developing lung trajectory in males and females, and sex-specific differences in the prevalence of chronic lung diseases, such as asthma and bronchopulmonary dysplasia. The objectives of this study were to investigate the early developing fetal lung for transcriptomic correlates of postconception age (maturity) and sex, and their associations with chronic lung diseases. We analyzed whole-lung transcriptome profiles of 61 females and 78 males at 54-127 days postconception (dpc) from nonsmoking mothers using unsupervised principal component analysis and supervised linear regression models. We identified dominant transcriptomic correlates for postconception age and sex with corresponding gene sets that were enriched for developing lung structural and functional ontologies. We observed that the transcriptomic sex difference was not a uniform global time shift/lag, rather, lungs of males appear to be more mature than those of females before 96 dpc, and females appear to be more mature than males after 96 dpc. The age correlate gene set was consistently enriched for asthma and bronchopulmonary dysplasia genes, but the sex correlate gene sets were not. Despite sex differences in the developing fetal lung transcriptome, postconception age appears to be more dominant than sex in the effect of early fetal lung developments on disease risk during this early pseudoglandular phase of development.

'WNT-er is coming': WNT signalling in chronic lung diseases

Chronic lung diseases represent a major public health problem with only limited therapeutic options. An important unmet need is to identify compounds and drugs that target key molecular pathways involved in the pathogenesis of chronic lung diseases. Over the last decade, there has been extensive interest in investigating Wingless/integrase-1 (WNT) signalling pathways; and WNT signal alterations have been linked to pulmonary disease pathogenesis and progression. Here, we comprehensively review the cumulative evidence for WNT pathway alterations in chronic lung pathologies, including idiopathic pulmonary fibrosis, pulmonary arterial hypertension, asthma and COPD. While many studies have focused on the canonical WNT/β-catenin signalling pathway, recent reports highlight that non-canonical WNT signalling may also significantly contribute to chronic lung pathologies; these studies will be particularly featured in this review. We further discuss recent advances uncovering the role of WNT signalling early in life, the potential of pharmaceutically modulating WNT signalling pathways and highlight (pre)clinical studies describing promising new therapies for chronic lung diseases.

Respiratory Morbidity in Infants Born With a Congenital Lung Malformation

BACKGROUND AND OBJECTIVES

The actual frequency of respiratory symptoms related to congenital pulmonary malformations (CPMs) remains undetermined. The goal of this study was to prospectively evaluate the respiratory symptoms occurring in infants with prenatally diagnosed CPMs, identify factors associated with the occurrence of these symptoms, and evaluate their resolution after surgery.

METHODS

Infectious and noninfectious respiratory symptoms were prospectively collected in a French multicenter cohort of children with CPMs.

RESULTS

Eighty-five children were followed up to the mean age of 2.1 ± 0.4 years. Six children (7%) underwent surgery during the first 28 days of life. Of the 79 remaining children, 33 (42%) had respiratory symptoms during infancy before any surgery. Wheezing was the dominant symptom (24 of 79 [30%]), and only 1 infant had documented infection of the cystic lobe. Symptoms were more frequent in children with noncystic CPMs, prenatally (P = .01) or postnatally (P < .03), and with postnatally hyperlucent CPMs (P < .01). Sixty-six children underwent surgery during the follow-up period, and 40% of them displayed symptoms after the intervention. Six children had documented pneumonia during the postoperative period. At the end of the follow-up, pectus excavatum was observed in 10 children, significantly associated with thoracotomy (P < .02) or with surgery before the age of 6 months (P < .002).

CONCLUSIONS

CPMs are frequently associated with wheezing episodes. Surgery had no significant impact on these symptoms but was associated with a paradoxical increase in pulmonary infections, as well as an increased risk of pectus excavatum after thoracotomy.

Functional Effects of WNT1-Inducible Signaling Pathway Protein-1 on Bronchial Smooth Muscle Cell Migration and Proliferation in OVA-Induced Airway Remodeling

Upregulation of WISP1 has been demonstrated in lung remodeling. Moreover, it has been recently found that some signaling components of WNT pathway can activate GSK3β signaling to mediate remodeling of airway smooth muscle (ASM) in asthma. Therefore, we hypothesized that WISP1, a signaling molecule downstream of the WNT signaling pathway, is involved in PI3K/GSK3β signaling to mediate ASM remodeling in asthma. Our results showed that WISP1 depletion partly suppressed OVA-induced ASM hypertrophy in vivo. In vitro, WISP1 could induce hBSMC hypertrophy and proliferation, accompanied by upregulation of levels of PI3K, p-Akt, p-GSK3β, and its own expression. TGF-β treatment could increase expression of PI3K, p-Akt, p-GSK3β, and WISP1. SH-5 treatment could partly suppress TGF-β-induced hypertrophy and proliferation of hBSMC, and depress expression of p-GSK3β and WISP1. In conclusion, WISP1 may be a potential inducer of ASM proliferation and hypertrophy in asthma. The pro-remodeling effect of WISP1 is likely due to be involved in PI3K-GSK3β-dependent noncanonical TGF-β signaling.

DNA methylation profiling in human lung tissue identifies genes associated with COPD

Chronic obstructive pulmonary disease (COPD) is a smoking-related disease characterized by genetic and phenotypic heterogeneity. Although association studies have identified multiple genomic regions with replicated associations to COPD, genetic variation only partially explains the susceptibility to lung disease, and suggests the relevance of epigenetic investigations. We performed genome-wide DNA methylation profiling in homogenized lung tissue samples from 46 control subjects with normal lung function and 114 subjects with COPD, all former smokers. The differentially methylated loci were integrated with previous genome-wide association study results. The top 535 differentially methylated sites, filtered for a minimum mean methylation difference of 5% between cases and controls, were enriched for CpG shelves and shores. Pathway analysis revealed enrichment for transcription factors. The top differentially methylated sites from the intersection with previous GWAS were in CHRM1, GLT1D1, and C10orf11; sorted by GWAS P-value, the top sites included FRMD4A, THSD4, and C10orf11. Epigenetic association studies complement genetic association studies to identify genes potentially involved in COPD pathogenesis. Enrichment for genes implicated in asthma and lung function and for transcription factors suggests the potential pathogenic relevance of genes identified through differential methylation and the intersection with a broader range of GWAS associations.

Linking bronchopulmonary dysplasia to adult chronic lung diseases: role of WNT signaling

Bronchopulmonary dysplasia (BPD) is one of the most common chronic lung diseases in infants caused by pre- and/or postnatal lung injury. BPD is characterized by arrested alveolarization and vascularization due to extracellular matrix remodeling, inflammation, and impaired growth factor signaling. WNT signaling is a critical pathway for normal lung development, and its altered signaling has been shown to be involved in the onset and progression of incurable chronic lung diseases in adulthood, such as chronic obstructive pulmonary disease (COPD) or idiopathic pulmonary fibrosis (IPF). In this review, we summarize the impact of WNT signaling on different stages of lung development and its potential contribution to developmental lung diseases, especially BPD, and chronic lung diseases in adulthood.

Immune Modulation of the T Cell Response in Asthma through Wnt10b

Asthma is a chronic inflammatory disease, which is characterized by activation of CD4(+) T helper 2 cells orchestrating an allergic airway response. Whereas the role of Wnt family members in regulating T cell maintenance and maturation is established, their contribution to T cell activation in allergic asthma is not known. We hypothesized that Wnt10b plays a role in the modulation of the allergic airway response and affects T cell activation and polarization. Using an in vivo house dust mite asthma model, Wnt10b-deficient (Wnt10b(-/-)) mice were allergen-sensitized and inflammation, as well as T cell activation, was studied in vivo and in vitro. Wnt10b(-/-) mice exhibited an augmented inflammatory phenotype with an increase in eosinophils in the bronchoalveolar lavage and IL-4 and IL-13 in the lungs when compared with wild-type mice. In vitro studies confirmed an increased T helper type 2 polarization and increased T cell activation of Wnt10b(-/-) cells. Accordingly, the percentage of naive T cells was elevated by the addition of recombinant Wnt10b protein. Finally, Wnt10b(-/-) mice exhibited an increase in the percentage of effector T cells in the lungs after house dust mite sensitization, which indicated a heightened activation state, measured by an increased percentage of CD69(hi)CD11a(hi) cells. These findings suggest that Wnt10b plays an important role in regulating asthmatic airway inflammation through modification of the T cell response and is a prospective target in the disease process.

Circulating MicroRNAs: Association with Lung Function in Asthma

BACKGROUND

MicroRNAs are key transcriptional and network regulators previously associated with asthma susceptibility. However, their role in relation to asthma severity has not been delineated.

OBJECTIVE

We hypothesized that circulating microRNAs could serve as biomarkers of changes in lung function in asthma patients.

METHODS

We isolated microRNAs from serum samples obtained at randomization for 160 participants of the Childhood Asthma Management Program. Using a TaqMan microRNA array containing 754 microRNA primers, we tested for the presence of known asthma microRNAs, and assessed the association of the individual microRNAs with lung function as measured by FEV1/FVC, FEV1% and FVC%. We further tested the subset of FEV1/FVC microRNAs for sex-specific and lung developmental associations.

RESULTS

Of the 108 well-detected circulating microRNAs, 74 (68.5%) had previously been linked to asthma susceptibility. We found 22 (20.3%), 4 (3.7%) and 8 (7.4%) microRNAs to be associated with FEV1/FVC, FEV1% and FVC%, respectively. 8 (of 22) FEV1/FVC, 3 (of 4) FEV1% and 1 (of 8) FVC% microRNAs had functionally validated target genes that have been linked via genome wide association studies to asthma and FEV1 change. Among the 22 FEV1/FVC microRNAs, 9 (40.9%) remain associated with FEV1/FVC in boys alone in a sex-stratified analysis (compared with 3 FEV1/FVC microRNAs in girls alone), 7 (31.8%) were associated with fetal lung development, and 3 (13.6%) in both. Ontology analyses revealed enrichment for pathways integral to asthma, including PPAR signaling, G-protein coupled signaling, actin and myosin binding, and respiratory system development.

CONCLUSIONS

Circulating microRNAs reflect asthma biology and are associated with lung function differences in asthmatics. They may represent biomarkers of asthma severity.

WISP1 mediates IL-6-dependent proliferation in primary human lung fibroblasts

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal interstitial lung disease. IPF is characterized by epithelial cell injury and reprogramming, increases in (myo)fibroblasts, and altered deposition of extracellular matrix. The Wnt1-inducible signaling protein 1 (WISP1) is involved in impaired epithelial-mesenchymal crosstalk in pulmonary fibrosis. Here, we aimed to further investigate WISP1 regulation and function in primary human lung fibroblasts (phLFs). We demonstrate that WISP1 is directly upregulated by Transforming growth factor β1 (TGFβ1) and Tumor necrosis factor α (TNFα) in phLFs, using a luciferase-based reporter system. WISP1 mRNA and protein secretion increased in a time- and concentration-dependent manner by TGFβ1 and TNFα in phLFs, as analysed by qPCR and ELISA, respectively. Notably, WISP1 is required for TGFβ1- and TNFα-dependent induction of interleukin 6 (IL-6), a mechanism that is conserved in IPF phLFs. The siRNA-mediated WISP1 knockdown led to a significant IL-6 reduction after TGFβ1 or TNFα stimulation. Furthermore, siRNA-mediated downregulation or antibody-mediated neutralization of WISP1 reduced phLFs proliferation, a process that was in part rescued by IL-6. Taken together, these results strongly indicate that WISP1-induced IL-6 expression contributes to the pro-proliferative effect on fibroblasts, which is likely orchestrated by a variety of profibrotic mediators, including Wnts, TGFβ1 and TNFα.

The effects of in utero vitamin D deficiency on airway smooth muscle mass and lung function

We have previously demonstrated increased airway smooth muscle (ASM) mass and airway hyperresponsiveness in whole-life vitamin D-deficient female mice. In this study, we aimed to uncover the molecular mechanisms contributing to altered lung structure and function. RNA was extracted from lung tissue of whole-life vitamin D-deficient and -replete female mice, and gene expression patterns were profiled by RNA sequencing. The data showed that genes involved in embryonic organ development, pattern formation, branching morphogenesis, Wingless/Int signaling, and inflammation were differentially expressed in vitamin D-deficient mice. Network analysis suggested that differentially expressed genes were connected by the hubs matrix metallopeptidase 9; NF-κ light polypeptide gene enhancer in B cells inhibitor, α; epidermal growth factor receptor; and E1A binding protein p300. Given our findings that developmental pathways may be altered, we investigated if the timing of vitamin D exposure (in utero vs. postnatal) had an impact on lung health outcomes. Gene expression was measured in in utero or postnatal vitamin D-deficient mice, as well as whole-life vitamin D-deficient and -replete mice at 8 weeks of age. Baseline lung function, airway hyperresponsiveness, and airway inflammation were measured and lungs fixed for lung structure assessment using stereological methods and quantification of ASM mass. In utero vitamin D deficiency was sufficient to increase ASM mass and baseline airway resistance and alter lung structure. There were increased neutrophils but decreased lymphocytes in bronchoalveolar lavage. Expression of inflammatory molecules S100A9 and S100A8 was mainly increased in postnatal vitamin D-deficient mice. These observations suggest that in utero vitamin D deficiency can alter lung structure and function and increase inflammation, contributing to symptoms in chronic diseases, such as asthma.