Potential contribution of IL-7 to allergen-induced eosinophilic airway inflammation in asthma

Investigating immune profile by CyTOF in individuals with long-standing type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease caused by T-cell mediated destruction of pancreatic beta cells. Eosinophils are found in pancreatic tissue from individuals with T1D. Eosinophilic suppression of T cells is dependent of the protein galectin-10. Little is known when it comes to the role of eosinophil granulocytes in type 1 diabetes. Here we show that individuals with long-standing T1D had lower levels of galectin-10^hi eosinophils and a subgroup of galectin-10^hi eosinophils were entirely absent in all T1D patients. In addition, 7% immature eosinophils were present in the circulation of T1D patients whereas 0.8% in healthy individuals. Furthermore, higher levels of CD4+CD8+ T cells and Th17 cells were observed in patients with T1D. Blood samples from 12 adult individuals with long-standing T1D and 12 healthy individuals were compared using cytometry by time-of-flight. Lower levels of galectin-10^hi eosinophils, which are potent T cell suppressors, in individuals with T1D could indicate that activated T cells are enabled to unrestrictedly kill the insulin producing beta cells. This is the first study showing absence of galectin-10^hi eosinophilic subgroup in individuals with T1D compared with healthy controls. This study is a first important step toward unraveling the role of the eosinophils in patients with T1D.

Association of asthma genetic variants with asthma-associated traits reveals molecular pathways of eosinophilic asthma

INTRODUCTION

Asthma is a complex, polygenic, heterogenous inflammatory disease. Recently, we generated a list of 128 independent single nucleotide polymorphisms (SNPs) associated with asthma in genome-wide association studies. However, it is unknown if asthma SNPs are associated with specific asthma-associated traits such as high eosinophil counts, atopy, and airway obstruction, revealing molecular endotypes of this disease. Here, we aim to identify the association between asthma SNPs and asthma-associated traits and assess expression quantitative trait locus (e-QTLs) to reveal their downstream functional effects and find drug targets.

METHODS

Association analyses between 128 asthma SNPs and associated traits (blood eosinophil numbers, atopy, airway obstruction, airway hyperresponsiveness) were conducted using regression modelling in population-based studies (Lifelines N = 32,817/Vlagtwedde-Vlaardingen N = 1554) and an asthma cohort (Dutch Asthma genome-wide association study N = 917). Functional enrichment and pathway analysis were performed with genes linked to the significant SNPs by e-QTL analysis. Genes were investigated to generate novel drug targets.

RESULTS

We identified 69 asthma SNPs that were associated with at least one trait, with 20 SNPs being associated with multiple traits. The SNP annotated to SMAD3 was the most pleiotropic. In total, 42 SNPs were associated with eosinophil counts, 18 SNPs with airway obstruction, and 21 SNPs with atopy. We identified genetically driven pathways regulating eosinophilia. The largest network of eosinophilia contained two genes (IL4R, TSLP) targeted by drugs currently available for eosinophilic asthma. Several novel targets were identified such as IL-18, CCR4, and calcineurin.

CONCLUSION

Many asthma SNPs are associated with blood eosinophil counts and genetically driven molecular pathways of asthma-associated traits were identified.

Critical role of m6A modification in T-helper cell disorders

Diseases with T-helper cell subset imbalance involve multiple systems and organs. In addition to this, the pathogenesis of these diseases is always complex, and involves Th1, Th2, Th9, Th17, Th22, and Tfh cells. T-helper cell subset imbalance mediates immune responses to various pathogenic factors, by secreting specific cytokines. Although several studies have revealed the specific mechanisms of the occurrence and development of these diseases from different aspects, there is still a need for more comprehensive and in-depth studies that can compensate for the corresponding gaps in the diagnosis, targeted therapy, and prognosis of these diseases. N6-methyladenosine(m⁶A) modification is the most prevalent and abundant post-transcriptional modification in eukaryotic RNAs. In recent years, the critical role of m⁶A modification has been confirmed in multiple diseases with T-helper cell subset imbalance. m⁶A modification affects the immune cell development, inflammatory processes, biological behaviour of tumours, and immune response in these diseases. In this review, we focussed on how the enzymes involved in m⁶A modification, directly or indirectly, influence the pathogenesis and phenotype of various diseases with T-helper cell subset imbalance, and could therefore, serve as potential diagnostic markers and therapeutic targets for these diseases. In addition, this review also discusses the focus of future research in this area. Finally, we summarise the prospects of m⁶A modification in immunotherapy and chemotherapy.

DNA Methylation and Asthma Acquisition during Adolescence and Post-Adolescence, an Epigenome-Wide Longitudinal Study

The role of epigenetics in the pathogenesis of asthma acquisition in adolescence and post-adolescence has been unknown. We carried out a longitudinal epigenome-wide association study, using data from the Isle of Wight Birth Cohort (IOWBC). To improve statistical power, we first screened CpGs based on associations of DNA methylation (DNAm) at an age of 10 years (pre-adolescence) with asthma acquisition at 10-18 years (during adolescence). A logistic regression with repeated measures was applied to CpGs that passed screening to examine the associations of pre-adolescence DNAm with asthma acquisition from 10-18 years and 18-26 years, with an interaction term to evaluate transition period specificity. Findings were further tested in an independent birth cohort, ALSPAC. In total, 205 CpGs (with 150 being females) showed associations with asthma acquisition (main or interaction effects) at FDR = 0.05 in IOWBC, of which 112 (90 being females) showed consistent associations in the ALSPAC. Genes that the identified CpGs were mapped to, e.g., AKAP1 and ENO1, have been shown to be associated with the risk of asthma. Our findings indicated that DNAm at specific CpGs was associated with asthma acquisition. CpGs showing such associations were likely to be different between males and females and, at certain CpGs, were unique to a specific transition period.

The Association of IL7R rs6897932 with Risk of Multiple Sclerosis in Southern Chinese

OBJECTIVE

To investigate the association between IL7R rs6897932 and multiple sclerosis (MS) in southern Chinese people.

METHODS

In total, 147 MS patients and 530 healthy controls were recruited according to the revised McDonald criteria. The TaqMan method was used for genotyping.

RESULTS

With genetic models, we can observe that the additive model, the dominant model, and the recessive model of IL7R rs6897932 were significantly associated with MS [additive model: p=0.032; dominant model (adjusted): p<0.001, OR=3.61 (95% CI 2.25-5.83); recessive model (adjusted): p<0.001, OR=6.80 (95% CI 3.49-13.89)].

CONCLUSION

Our results suggest that IL7R rs6897932 is associated with MS in a southern Chinese population. More and larger MS studies to explore the genetic risk factors of MS are warranted.

Prolonged activation of nasal immune cell populations and development of tissue-resident SARS-CoV-2-specific CD8+ T cell responses following COVID-19

Systemic immune cell dynamics during coronavirus disease 2019 (COVID-19) are extensively documented, but these are less well studied in the (upper) respiratory tract, where severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replicates^1-6. Here, we characterized nasal and systemic immune cells in individuals with COVID-19 who were hospitalized or convalescent and compared the immune cells to those seen in healthy donors. We observed increased nasal granulocytes, monocytes, CD11c⁺ natural killer (NK) cells and CD4⁺ T effector cells during acute COVID-19. The mucosal proinflammatory populations positively associated with peripheral blood human leukocyte antigen (HLA)-DR^low monocytes, CD38⁺PD1⁺CD4⁺ T effector (T_eff) cells and plasmablasts. However, there was no general lymphopenia in nasal mucosa, unlike in peripheral blood. Moreover, nasal neutrophils negatively associated with oxygen saturation levels in blood. Following convalescence, nasal immune cells mostly normalized, except for CD127⁺ granulocytes and CD38⁺CD8⁺ tissue-resident memory T cells (T_RM). SARS-CoV-2-specific CD8⁺ T cells persisted at least 2 months after viral clearance in the nasal mucosa, indicating that COVID-19 has both transient and long-term effects on upper respiratory tract immune responses.

Interleukin-7 Biology and Its Effects on Immune Cells: Mediator of Generation, Differentiation, Survival, and Homeostasis

Interleukin-7 (IL-7), a molecule known for its growth-promoting effects on progenitors of B cells, remains one of the most extensively studied cytokines. It plays a vital role in health maintenance and disease prevention, and the congenital deficiency of IL-7 signaling leads to profound immunodeficiency. IL-7 contributes to host defense by regulating the development and homeostasis of immune cells, including T lymphocytes, B lymphocytes, and natural killer (NK) cells. Clinical trials of recombinant IL-7 have demonstrated safety and potent immune reconstitution effects. In this article, we discuss IL-7 and its functions in immune cell development, drawing on a substantial body of knowledge regarding the biology of IL-7. We aim to answer some remaining questions about IL-7, providing insights essential for designing new strategies of immune intervention.

Altered plasma cytokines in dogs with atopic dermatitis

BACKGROUND

Canine (Canis lupus familiaris) atopic dermatitis (AD) shares similar clinical signs to human AD. The abnormal immune response of AD is orchestrated by T lymphocytes, and may include variable involvement of cytokines, regulatory T (Treg) cells, eosinophils, mast cells and other immune components. Helper T (Th)2 cytokines often predominate initially, followed by Th1 cytokines in more chronic phases.

HYPOTHESIS/OBJECTIVES

Pro-inflammatory and Treg cytokines have been shown to play a role in human AD, yet their importance is not clear in canine AD. Hence, this study aimed to measure the concentrations of cytokines/chemokines not traditionally associated with Th1/Th2 response.

ANIMALS

Canine AD patients (n = 27), compared to control dogs (n = 11).

METHODS AND MATERIALS

A total of 19 plasma cytokines were assayed using canine specific multiplex immuno-assays.

RESULTS

The plasma concentrations of CXC Motif Chemokine Ligand 8 (CXCL8), interleukin (IL)-7 and IL-15 cytokines were elevated in canine AD patients, compared to control dogs. In addition, stem-cell factor (SCF) concentrations were reduced in the plasma of canine AD patients compared to control dogs. Distinct cytokine profiles were found in dogs belonging to the Staffordshire breeds, a group with increased risk of AD. In particular, granulocyte-macrophage colony-stimulating factor (GM-CSF) had significantly elevated concentrations.

CONCLUSIONS AND CLINICAL RELEVANCE

Some of the plasma cytokine alterations in canine AD described here, particularly of IL-7, have not been reported previously. Monitoring these distinctive cytokine alterations could be useful for diagnosis and monitoring of canine AD in dogs.

N 6-Methyladenosine Methylomic Landscape of Lung Tissues in Murine Acute Allergic Asthma

Allergic asthma is well known as a common respiratory disorder comprising an allergic inflammatory nature and excessive immune characteristic. N ⁶-methyladenosine (m6A) methylation is an RNA epigenetic modification that post-transcriptionally regulates gene expression and function by affecting the RNA fate. Currently, m6A methylation is gaining attention as a mechanism of immunoregulation. However, whether m6A methylation engages the pathological process of asthma remains uncertain. Here, we present the m6A methylomic landscape in the lung tissues of ovalbumin-induced acute asthma mice using MeRIP-seq and RNA-seq. We identified 353 hypermethylated m6A peaks within 329 messenger RNAs (mRNAs) and 150 hypomethylated m6A peaks within 143 mRNAs in the lung tissues of asthmatic mice. These differentially methylated mRNAs were found to be involved in several immune function-relevant signaling pathways. In addition, we predicted 25 RNA-binding proteins that recognize the differentially methylated peak sites by exploring public databases, and the roles of these proteins are mostly related to mRNA biogenesis and metabolism. To further investigate the expression levels of the differentially methylated genes, we performed combined analysis of the m6A methylome and transcriptome data and identified 127 hypermethylated mRNAs (107 high and 20 low expression) and 43 hypomethylated mRNAs with differential expressions (9 high and 34 low expression). Of these, there are a list of mRNAs involved in immune function and regulation. The present results highlight the essential role of m6A methylation in the pathogenesis of asthma.

Locally Adjust Networks Based on Connectivity and Semantic Similarities for Disease Module Detection

For studying the pathogenesis of complex diseases, it is important to identify the disease modules in the system level. Since the protein-protein interaction (PPI) networks contain a number of incomplete and incorrect interactome, most existing methods often lead to many disease proteins isolating from disease modules. In this paper, we propose an effective disease module identification method IDMCSS, where the used human PPI networks are obtained by adding some potential missing interactions from existing PPI networks, as well as removing some potential incorrect interactions. In IDMCSS, a network adjustment strategy is developed to add or remove links around disease proteins based on both topological and semantic information. Next, neighboring proteins of disease proteins are prioritized according to a suggested similarity between each of them and disease proteins, and the protein with the largest similarity with disease proteins is added into a candidate disease protein set one by one. The stopping criterion is set to the boundary of the disease proteins. Finally, the connected subnetwork having the largest number of disease proteins is selected as a disease module. Experimental results on asthma demonstrate the effectiveness of the method in comparison to existing algorithms for disease module identification. It is also shown that the proposed IDMCSS can obtain the disease modules having crucial biological processes of asthma and 12 targets for drug intervention can be predicted.

Genetic drivers of m6A methylation in human brain, lung, heart and muscle

The most prevalent post-transcriptional mRNA modification, N⁶-methyladenosine (m⁶A), plays diverse RNA-regulatory roles, but its genetic control in human tissues remains uncharted. Here we report 129 transcriptome-wide m⁶A profiles, covering 91 individuals and 4 tissues (brain, lung, muscle and heart) from GTEx/eGTEx. We integrate these with interindividual genetic and expression variation, revealing 8,843 tissue-specific and 469 tissue-shared m⁶A quantitative trait loci (QTLs), which are modestly enriched in, but mostly orthogonal to, expression QTLs. We integrate m⁶A QTLs with disease genetics, identifying 184 GWAS-colocalized m⁶A QTL, including brain m⁶A QTLs underlying neuroticism, depression, schizophrenia and anxiety; lung m⁶A QTLs underlying expiratory flow and asthma; and muscle/heart m⁶A QTLs underlying coronary artery disease. Last, we predict novel m⁶A regulators that show preferential binding in m⁶A QTLs, protein interactions with known m⁶A regulators and expression correlation with the m⁶A levels of their targets. Our results provide important insights and resources for understanding both cis and trans regulation of epitranscriptomic modifications, their interindividual variation and their roles in human disease.

Characterization of Cytokines and Proliferation Marker Ki67 in Chronic Rhinosinusitis with Nasal Polyps: A Pilot Study

Background and Objectives: Chronic rhinosinusitis (CRS) is a condition that affects as much as 10.9% of the population and, along with presence of nasal polyps, is associated with significant morbidity and decreased quality of life. Studies on molecular pathways that have been activated in nasal polyp tissue are mainly based on cytokine concentration detection. Therefore, our aim is to investigate the complex appearance, relative distribution and interlinks of IL-1, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12 and Ki 67 in chronic rhinosinusitis with nasal polyps (CRSwNP) affected human nasal mucosa. Materials and Methods: Samples of nasal polyps were obtained from 12 patients with previously diagnosed CRSwNP and no prior surgery. Control group consisted of samples from 17 otherwise healthy individuals with isolated nasal septum deviation. Tissues were stained for IL-1, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12 and Ki67 immunohistochemically. Non-parametric statistic, Mann–Whitney U test and Spearman’s rank correlation coefficient were used. Results: All factors, except connective tissue cytokine IL-10 and proliferation marker Ki-67, had increased presence in connective tissue and decreased presence in epithelium of nasal polyps when compared to controls. Very strong and strong positive correlations between factors were observed. Conclusions: Decreased appearance of IL-1α, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12 positive structures in the nasal epithelium with selective increase of IL-1α and IL-12 in nasal subepithelial connective tissue characterize the cytokine endotype with dysfunctional epithelial barrier and local stimulation of immune response in the connective tissue in case of chronic rhinosinusitis with polyps. Decrease of IL-6 in both—epithelium and connective tissue with strong correlation between it and IL-7 and IL-10 in connective tissue suggests significant stimulation of this regulatory cytokine and, possibly, the important role in pathogenesis of the development in nasal polyps. Correlations between Ki67 and cytokines indicate possible involvement of IL-4, IL-7 and IL-12 in regulation of cellular proliferation.

Airways exposure of bacterial superantigen SEB enhances bone marrow eosinophil population and facilitates its egress to blood and lung tissue

BACKGROUND

Differentiation of bone marrow eosinophils (BM-EO) and its trafficking to peripheral blood and respiratory mucosa are a hallmark of inflammatory diseases. Staphylococcal enterotoxin B (SEB) has been shown to aggravate airways eosinophilic inflammation. This study aimed to investigate the effects of mouse airways SEB exposure on BM-EO population, as well as its adhesive properties and release of cytokines/chemokines that orchestrate BM-EO trafficking to lungs.

METHODS

Male BALB/c mice were intranasally exposed to SEB (1 μg), and at 4, 16, 24 and 48 h thereafter, bone marrow (BM), circulating blood and bronchoalveolar lavage (BAL) fluid were collected. Levels of cytokines/chemokines and expressions of VLA-4 and CCR3 in BM were evaluated. Adhesion of BM to ICAM-1 and VCAM-1 were also evaluated.

RESULTS

SEB exposure promoted a marked eosinophil influx to BAL at 16 and 24 h after exposure, which was accompanied by significant increases in counts of immature (16 h) and mature (4 to 48 h) forms of eosinophil in BM, along with blood eosinophilia (16 h). In BM, higher levels of eotaxin, IL-5, IL-4, IL-3 and IL-7 were detected at 16 to 48 h. SEB also significantly increased CCR3 expression and calcium levels in BM-EO, and enhanced the cell adhesion to ICAM-1 (24 h) and ICAM-1 (48 h).

CONCLUSION

Airways SEB exposure increases the number of eosinophils in BM by mechanisms involving a network of cytokine and chemokine release, facilitating the BM-EO adhesion to ICAM-1 and VCAM-1 to gain access to the peripheral blood and lung tissues.

Interleukin 7 receptor is required for myeloid cell homeostasis and reconstitution by hematopoietic stem cells

Respiratory diseases are a leading cause of death worldwide, with vulnerability to disease varying greatly between individuals. The reasons underlying disease susceptibility are unknown, but there is often a variable immune response in lungs often. Recently, we identified a surprising novel role for the interleukin 7 receptor (IL7R), a primarily lymphoid-associated regulator, in fetal-specified, lung-resident macrophage development. Here, we report that traditional, hematopoietic stem cell-derived myeloid cells in the adult lung, peripheral blood, and bone marrow also depend on IL7R expression. Using single- and double-germline knockout models, we found that eosinophil numbers were reduced on deletion of IL7Rα. We then employed two Cre recombinase models in lineage tracing experiments to test whether these cells developed through an IL7Rα+ pathway. Despite the impact of IL7Rα deletion, IL7R-Cre labeled only a minimal fraction of eosinophils. We therefore examined the intrinsic versus extrinsic requirement for IL7R in the production of eosinophils using reciprocal hematopoietic stem cell transplantation assays. These assays revealed that extrinsic, but not eosinophil-intrinsic, IL7R is required for eosinophil reconstitution by HSCs in the adult lung. To determine which external factors may be influencing eosinophil development and survival, we performed a cytokine array analysis between wild-type and IL7Rα-deficient mice and found several differentially regulated proteins. These findings expand on our previous report that IL7R is required not only for proper lymphoid cell development and homeostasis, but also for myeloid cell homeostasis in tissues.

Targeting the interleukin-7 receptor alpha by an anti-CD127 monoclonal antibody improves allergic airway inflammation in mice

BACKGROUND

Interleukin-7 (IL-7) is the most important cytokine for T-cell homeostasis. IL-7 signals through the IL-7 receptor (IL-7R) which is composed of an alpha chain (IL-7Rα), also called CD127 and a common gamma chain. T lymphocytes, especially T helper type 2, play a crucial role in the pathobiology of allergic asthma.

OBJECTIVE

To study the effects of an anti-CD127 monoclonal antibody (mAb) in a murine model of allergic airway inflammation induced by house dust mite (HDM).

METHODS

Allergic airway inflammation was induced in mice using a protocol comprising 4 weekly percutaneous sensitizations followed by 2 weekly intranasal challenges with total HDM extracts and treated by intraperitoneal injections of an anti-CD127 mAb. Because CD127 is shared by both IL-7R and the receptor for thymic stromal lymphopoietin (TSLP), a group of mice was also treated with an anti-IL-7 mAb to block only the IL-7 signalling pathway.

RESULTS

Anti-CD127 mAb-treated mice showed significantly lower airway resistance in response to methacholine and improvement in lung histology compared with isotype mAb-treated animals. Anti-CD127 mAb treatment significantly decreased the mRNA expression of Th2 cytokines (IL-4, IL-5, and IL-13) and chemokines (CCL5/RANTES) in lung tissue, decreased the secretion of Th2 cytokines (IL-4, IL-5, and IL-13) and chemokines (CXCL1 and CCL11/eotaxin) in bronchoalveolar lavage fluid (BALF), decreased serum HDM-specific IgE, and reduced the number of total leucocytes and leucocyte subpopulations such as eosinophils, macrophages, lymphocytes, T lymphocytes, and ILC2 in BALF and lung tissue. Mice treated with anti-IL-7 mAb also showed less allergic airway inflammation as evidenced by significantly lower airway resistance and fewer leucocytes in BALF and lung tissue compared to mice treated with the corresponding isotype control mAb.

CONCLUSION AND CLINICAL RELEVANCE

Targeting the IL-7Rα by an anti-CD127 mAb improves allergic airway inflammation in mice and presents as a potential therapeutic approach for allergic asthma.

Effect of IL‑7 on Th17 cell responses in a mouse model of neutrophilic asthma

Neutrophilic asthma (NA) is characterized by neutrophil-mediated inflammation and the presence of Th17 cells. However, the mechanisms underlying Th17 cell responses in NA remain unknown. The aim of the present study was to examine the effects of interleukin (IL)-7 on Th17 cell responses in NA. A NA mouse model was sensitized by airway delivery of ovalbumin (OVA) and lipopolysaccharide and challenged with 1% OVA aerosol from day 21 for 3 consecutive days. Airway resistance was then measured to assess airway hyper-responsiveness (AHR). Cells from bronchoalveolar lavage fluid (BALF) underwent Diff-Quick and hematoxylin and eosin staining for classification. The levels of IL-17 in the BALF were determined by ELISA. The effects of IL-7 administration and STAT5 inhibition on Th17 cells were also characterized in vitro using splenic CD4⁺ T cells. Ki-67, Bcl-2 and activated caspase-3 expression in differentiated Th17 cells were analyzed by flow cytometry. The mouse model of NA was characterized by increased AHR, elevated levels of IL-17, high neutrophil counts in BALF, accumulated inflammatory cells in the lung and Th17 cell responses. IL-7 promoted the expression of Ki-67 and Bcl-2 while reducing caspase-3 expression. STAT5 inhibitor treatment decreased the levels of Ki-67 and Bcl-2, and resulted in increased expression of caspase-3. These results suggested that the IL-7/JAK/STAT5 signaling pathway may be involved in Th17 cell responses in NA.

Distinct associations of sputum and oral microbiota with atopic, immunologic, and clinical features in mild asthma

BACKGROUND

Whether microbiome characteristics of induced sputum or oral samples demonstrate unique relationships to features of atopy or mild asthma in adults is unknown.

OBJECTIVE

We sought to determine sputum and oral microbiota relationships to clinical or immunologic features in mild atopic asthma and the impact on the microbiota of inhaled corticosteroid (ICS) treatment administered to ICS-naive subjects with asthma.

METHODS

Bacterial microbiota profiles were analyzed in induced sputum and oral wash samples from 32 subjects with mild atopic asthma before and after inhaled fluticasone treatment, 18 atopic subjects without asthma, and 16 nonatopic healthy subjects in a multicenter study (NCT01537133). Associations with clinical and immunologic features were examined, including markers of atopy, type 2 inflammation, immune cell populations, and cytokines.

RESULTS

Sputum bacterial burden inversely associated with bronchial expression of type 2 (T2)-related genes. Differences in specific sputum microbiota also associated with T2-low asthma phenotype, a subgroup of whom displayed elevations in lung inflammatory mediators and reduced sputum bacterial diversity. Differences in specific oral microbiota were more reflective of atopic status. After ICS treatment of patients with asthma, the compositional structure of sputum microbiota showed greater deviation from baseline in ICS nonresponders than in ICS responders.

CONCLUSIONS

Novel associations of sputum and oral microbiota to immunologic features were observed in this cohort of subjects with or without ICS-naive mild asthma. These findings confirm and extend our previous report of reduced bronchial bacterial burden and compositional complexity in subjects with T2-high asthma, with additional identification of a T2-low subgroup with a distinct microbiota-immunologic relationship.

Interleukin-7 protects against bacterial respiratory infection by promoting IL-17A-producing innate T-cell response

Interleukin-7 (IL-7) is a critical cytokine in B- and T-lymphocyte development and maturation. Recent evidence suggests that IL-7 is a preferential homeostatic and survival factor for RORγt⁺ innate T cells such as natural killer T (NKT) cells, γδT cells, and mucosal-associated invariant T (MAIT) cells in the periphery. Given the important contribution of these populations in antibacterial immunity at barrier sites, we questioned whether IL-7 could be instrumental in boosting the local host immune response against respiratory bacterial infection. By using a cytokine-monoclonal antibody approach, we illustrated a role for topical IL-7 delivery in increasing the pool of RORγt⁺ IL-17A-producing innate T cells. Prophylactic IL-7 treatment prior to Streptococcus pneumoniae infection led to better bacterial containment, a process associated with increased neutrophilia and that depended on γδT cells and IL-17A. Last, combined delivery of IL-7 and α-galactosylceramide (α-GalCer), a potent agonist for invariant NKT (iNKT) cells, conferred an almost total protection in terms of survival, an effect associated with enhanced IL-17 production by innate T cells and neutrophilia. Collectively, we provide a proof of concept that IL-7 enables fine-tuning of innate T- cell functions. This might pave the way for considering IL-7 as an innovative biotherapeutic against bacterial infection.

Multi-Method Molecular Characterisation of Human Dust-Mite-associated Allergic Asthma

Asthma is a chronic inflammatory disorder of the airways. Disease presentation varies greatly in terms of cause, development, severity, and response to medication, and thus the condition has been subdivided into a number of asthma phenotypes. There is still an unmet need for the identification of phenotype-specific markers and accompanying molecular tools that facilitate the classification of asthma phenotype. To this end, we utilised a range of molecular tools to characterise a well-defined group of female adults with poorly controlled atopic asthma associated with house dust mite (HDM) allergy, relative to non-asthmatic control subjects. Circulating messenger RNA (mRNA) and microRNA (miRNA) were sequenced and quantified, and a differential expression analysis of the two RNA populations performed to determine how gene expression and regulation varied in the disease state. Further, a number of circulating proteins (IL-4, 5, 10, 13, 17 A, Eotaxin, GM-CSF, IFNy, MCP-1, TARC, TNFα, Total IgE, and Endotoxin) were quantified to determine whether the protein profiles differed significantly dependent on disease state. Finally, we utilised a previously published assessment of the circulating “blood microbiome” performed using 16S rRNA amplification and sequencing. Asthmatic subjects displayed a range of significant alterations to circulating gene expression and regulation, relative to healthy control subjects, that may influence systemic immune activity. Notably, several circulating mRNAs were detected in just the asthma group or just in the control group, and many more were observed to be expressed at significantly different levels in the asthma group compared to the control group. Proteomic analysis revealed increased levels of inflammatory proteins within the serum, and decreased levels of the bacterial endotoxin protein in the asthmatic state. Comparison of blood microbiome composition revealed a significant increase in the Firmicutes phylum with asthma that was associated with a concomitant reduction in the Proteobacteria phylum. This study provides a valuable insight into the systemic changes evident in the HDM-associated asthma, identifies a range of molecules that are present in the circulation in a condition-specific manner (with clear biomarker potential), and highlights a range of hypotheses for further study.

Interleukin-7 gene polymorphism rs766736182 associates with the risk of asthma in children

BACKGROUND

Recently studies uncovered associations between polymorphisms of interleukin genes and the risk of asthma. However, the relationship between polymorphisms of interleukin-7 gene and the risk of children asthma has not been discovered yet. This study aims to investigate the relationship between single nucleotide polymorphisms (SNPs) on interleukin-7 gene and the risk of children asthma.

METHODS

We genotyped eight SNPs of interleukin-7 gene in blood samples from 437 asthma patients and 489 healthy controls to analyze potential associations of these SNPs with the risk of asthma in children.

RESULTS

A missense SNP rs766736182 (odds ratio (OR) = 2.185, 95% confidence interval (CI) = 1.561-2.252, P-value = 8.69468E-19) of the interleukin-7 gene is associated with the risk of children asthma.

CONCLUSIONS

This study reveals that SNP rs766736182 of interleukin-7 is the risk factor for children asthma and implies potential role of immune system in the pathogenesis of children asthma.

The common γ-chain cytokine IL-7 promotes immunopathogenesis during fungal asthma

Asthmatics sensitized to fungi are reported to have more severe asthma, yet the immunopathogenic pathways contributing to this severity have not been identified. In a pilot assessment of human asthmatics, those subjects sensitized to fungi demonstrated elevated levels of the common γ-chain cytokine IL-7 in lung lavage fluid, which negatively correlated with the lung function measurement PC20. Subsequently, we show that IL-7 administration during experimental fungal asthma worsened lung function and increased the levels of type 2 cytokines (IL-4, IL-5, IL-13), proallergic chemokines (CCL17, CCL22) and proinflammatory cytokines (IL-1α, IL-1β). Intriguingly, IL-7 administration also increased IL-22, which we have previously reported to drive immunopathogenic responses in experimental fungal asthma. Employing IL22CreR26ReYFP reporter mice, we identified γδ T cells, iNKT cells, CD4 T cells and ILC3s as sources of IL-22 during fungal asthma; however, only iNKT cells were significantly increased after IL-7 administration. IL-7-induced immunopathogenesis required both type 2 and IL-22 responses. Blockade of IL-7Rα in vivo resulted in attenuated IL-22 production, lower CCL22 levels, decreased iNKT cell, CD4 T-cell and eosinophil recruitment, yet paradoxically increased dynamic lung resistance. Collectively, these results suggest a complex role for IL-7 signaling in allergic fungal asthma.

Olfactory and middle meatal cytokine levels correlate with olfactory function in chronic rhinosinusitis

OBJECTIVES/HYPOTHESIS

The etiology of chronic rhinosinusitis (CRS)-associated olfactory loss is unclear, but may result from inflammatory changes in the olfactory epithelium that result in signaling dysfunction or loss of olfactory neurons. Several proinflammatory cytokines have been associated with CRS, but their expression within the olfactory cleft microenvironment and association with olfactory function is unknown.

STUDY DESIGN

Prospective case-control study.

METHODS

Mucus was collected from the olfactory cleft and middle meatus of 31 CRS without nasal polyps subjects, 36 CRS with nasal polyps (CRSwNP) subjects, and 12 healthy controls. Olfactory function was assessed using the validated Smell Identification Test (SIT). Site-specific levels of 14 cytokines/chemokines (interleukin [IL]-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17A, tumor necrosis factor-α, Eotaxin, RANTES [regulated on activation, normal T cell expressed and secreted]) were assessed using a multiplex flow cytometric bead assay and correlated with SIT scores.

RESULTS

Mucus cytokine levels in the olfactory cleft were strongly or moderately correlated with levels in the middle meatus for all but one measured inflammatory mediators. SIT scores were inversely correlated with levels of IL-2 (P = .006), IL-5 (P < .0001), IL-6 (P = .0009), IL-10 (P < .0001), and IL-13 (P < .0001), with significance largely driven by CRSwNP patients.

CONCLUSIONS

The inflammatory microenvironment within the olfactory cleft mirrors that within the middle meatus. Elevated levels of IL-2, IL-5, IL-6, IL-10, and IL-13 in olfactory cleft mucus are associated with reduced olfactory identification scores in CRS patients. Altered levels of select olfactory mucus cytokines could potentially have deleterious effects on olfactory neuron function and turnover.

LEVEL OF EVIDENCE

NA. Laryngoscope, 128:E304-E310, 2018.

Cytokine and Chemokine Profiling in Patients with Hand, Foot and Mouth Disease in Singapore and Malaysia

Hand, foot and mouth disease (HFMD) is a prevalent contagious childhood disease typically associated with fever, oral lesions and limb exanthema. While HFMD is caused by a plethora of serotypes of viruses under the genus Enterovirus within the Picornaviridae family, Coxsackievirus A16 (CV-A16) and Enterovirus 71 (EV-A71) are considered the main etiological agents. In recent years however, other viruses have also been isolated in considerable numbers from infected individuals in many regions, joining the legion commonly associated with HFMD. The present study investigated the cytokine and chemokine profiles of HFMD patients from Singapore and Malaysia for the first time. Comparative cohort studies of EV-A71-associated HFMD cases revealed that the Malaysia cohort had a distinct profile from the Singapore cohort, and this could be partly attributed by different EV-A71 genotypes. As the isolation of CV-A6, instead of CV-A16, had become prevalent in the Singapore cohort, it was also of particular interest to study the differential cytokine and chemokine profiles. Our data revealed that overlapping as well as unique profiles exist between the two major causative clinical isolates in the Singapore cohort. Having a better understanding of the respective immunological profiles could be useful for more accurate HFMD diagnosis, which is imperative for disease transmission control until multi-valent vaccines and/or broad-spectrum anti-viral drugs become available.

Hypertonic saline attenuates the cytokine-induced pro-inflammatory signature in primary human lung epithelia

Trauma/hemorrhagic shock is a complex physiological phenomenon that leads to dysregulation of many molecular pathways. For over a decade, hypertonic saline (HTS) has been used as an alternative resuscitation fluid in the setting of trauma/hemorrhagic shock. In addition to restoring circulating volume within the vascular space, studies have shown a positive immunomodulatory effect of HTS. Targeted studies have shown that HTS affects the transcription of several pro-inflammatory cytokines by inhibiting the NF-κB-IκB pathway in model cell lines and rats. However, few studies have been undertaken to assess the unbiased effects of HTS on the whole transcriptome. This study was designed to interrogate the global transcriptional responses induced by HTS and provides insight into the underlying molecular mechanisms and pathways affected by HTS. In this study, RNA sequencing was employed to explore early changes in transcriptional response, identify key mediators, signaling pathways, and transcriptional modules that are affected by HTS in the presence of a strong inflammatory stimulus. Our results suggest that primary human small airway lung epithelial cells (SAECS) exposed to HTS in the presence and absence of a strong pro-inflammatory stimulus exhibit very distinct effects on cellular response, where HTS is highly effective in attenuating cytokine-induced pro-inflammatory responses via mechanisms that involve transcriptional regulation of inflammation which is cell type and stimulus specific. HTS is a highly effective anti-inflammatory agent that inhibits the chemotaxis of leucocytes towards a pro-inflammatory gradient and may attenuate the progression of both the innate and adaptive immune response.

Asthma Biomarkers: Do They Bring Precision Medicine Closer to the Clinic?

Measurement of biomarkers has been incorporated within clinical research of asthma to characterize the population and to associate the disease with environmental and therapeutic effects. Regrettably, at present, there are no specific biomarkers, none is validated or qualified, and endotype-driven choices overlap. Biomarkers have not yet reached clinical practice and are not included in current asthma guidelines. Last but not least, the choice of the outcome upholding the value of the biomarkers is extremely difficult, since it has to reflect the mechanistic intervention while being relevant to both the disease and the particular person. On the verge of a new age of asthma healthcare standard, we must embrace and adapt to the key drivers of change. Disease endotypes, biomarkers, and precision medicine represent an emerging model of patient care building on large-scale biologic databases, omics and diverse cellular assays, health information technology, and computational tools for analyzing sizable sets of data. A profound transformation of clinical and research pattern from population to individual risk and from investigator-imposed subjective disease clustering (hypothesis driven) to unbiased, data-driven models is facilitated by the endotype/biomarker-driven approach.

Thy1+IL-7+ lymphatic endothelial cells in iBALT provide a survival niche for memory T-helper cells in allergic airway inflammation

Memory CD4(+) T helper (Th) cells are central to long-term protection against pathogens, but they can also be pathogenic and drive chronic inflammatory disorders. How these pathogenic memory Th cells are maintained, particularly at sites of local inflammation, remains unclear. We found that ectopic lymphoid-like structures called inducible bronchus-associated lymphoid tissue (iBALT) are formed during chronic allergic inflammation in the lung, and that memory-type pathogenic Th2 (Tpath2) cells capable of driving allergic inflammation are maintained within the iBALT structures. The maintenance of memory Th2 cells within iBALT is supported by Thy1(+)IL-7-producing lymphatic endothelial cells (LECs). The Thy1(+)IL-7-producing LECs express IL-33 and T-cell-attracting chemokines CCL21 and CCL19. Moreover, ectopic lymphoid structures consisting of memory CD4(+) T cells and IL-7(+)IL-33(+) LECs were found in nasal polyps of patients with eosinophilic chronic rhinosinusitis. Thus, Thy1(+)IL-7-producing LECs control chronic allergic airway inflammation by providing a survival niche for memory-type Tpath2 cells.

At the bench: understanding group 2 innate lymphoid cells in disease

The conventional paradigm of type 2 inflammatory responses is characterized by activation of CD4(+) Th2 cells that produce IL-4, IL-5, and IL-13, resulting in tissue eosinophil infiltration, mucus metaplasia, AHR, and IgE production. However, the recent discovery of ILC2s in mice and humans has brought forth a novel pathway in type 2 immunity that may work independent of, or in concert with, adaptive Th2 responses. ILC2s were described initially as lineage-negative lymphocytes that produce high levels of Th2 cytokines IL-5 and IL-13 in response to IL-25 and IL-33 and promote protection against helminth infections. More recent investigations have identified novel upstream regulators, as well as novel ILC2 products. ILC2s are found in mucosal surfaces, including respiratory tract and skin, and studies from experimental asthma and atopic dermatitis models support a role for ILC2s in promoting type 2 inflammatory responses. There are many unanswered questions about the role of ILC2s in chronic allergic diseases, including how ILC2s or upstream pathways can be targeted for therapy. As ILC2s are not antigen specific and may be activated after exposures to a variety of infectious agents and irritants thought to contribute to respiratory and skin diseases, future strategies to target ILC2 function in human disease may be promising. Our intent is to identify priority areas for ILC2 translational research based on basic research insights.

Subsets of airway myeloid-derived regulatory cells distinguish mild asthma from chronic obstructive pulmonary disease

BACKGROUND

Subsets of myeloid-derived regulatory cells (MDRCs), which are phenotypically similar to the myeloid-derived suppressor cells found in patients with cancer, have recently been appreciated as critical regulators of airway inflammation in mouse models of asthma.

OBJECTIVE

We test the hypothesis that subsets of airway MDRCs contribute differentially to the inflammatory milieu in human asthma and chronic obstructive pulmonary disease (COPD).

METHODS

We used bronchoalveolar lavage to identify and characterize human airway MDRCs from 10 healthy subjects, 9 patients with mild asthma, and 8 patients with COPD, none of whom were treated with inhaled or systemic corticosteroids. We defined subsets of airway MDRCs using flow cytometry, the molecular mediators they produce, and their abilities to regulate proliferation of polyclonally activated autologous T lymphocytes.

RESULTS

We found substantial differences in the functional potential of MDRC subsets in healthy subjects, patients with asthma, and patients with COPD, with these differences regulated by the nitrosative and oxidative free radicals and cytokines they produced. Nitric oxide-producing MDRCs suppressed and superoxide-producing MDRCs enhanced proliferation of polyclonally activated autologous CD4 T cells. HLA-DR(+)CD11b(+)CD11c(+)CD163(-) superoxide-producing MDRCs, which stimulated proliferation of autologous T cells, comprised a high fraction of MDRCs in the airways of patients with mild asthma or COPD but not those of healthy control subjects. CD11b(+)CD14(+)CD16(-)HLA-DR(-) nitric oxide-producing MDRCs, which suppressed T-cell proliferation, were present in high numbers in airways of patients with mild asthma but not patients with COPD or healthy control subjects.

CONCLUSION

Subsets of airway MDRCs conclusively discriminate patients with mild asthma, patients with COPD, and healthy subjects from each other. The distinctive activities of these MDRCs in patients with asthma or COPD might provide novel targets for new therapeutics for these common disorders. [Corrected]

Activation states of blood eosinophils in asthma

Asthma is characterized by airway inflammation rich in eosinophils. Airway eosinophilia is associated with exacerbations and has been suggested to play a role in airway remodelling. Recruitment of eosinophils from the circulation requires that blood eosinophils become activated, leading to their arrest on the endothelium and extravasation. Circulating eosinophils can be envisioned as potentially being in different activation states, including non-activated, pre-activated or 'primed', or fully activated. In addition, the circulation can potentially be deficient of pre-activated or activated eosinophils, because such cells have marginated on activated endothelium or extravasated into the tissue. A number of eosinophil surface proteins, including CD69, L-selectin, intercellular adhesion molecule-1 (ICAM-1, CD54), CD44, P-selectin glycoprotein ligand-1 (PSGL-1, CD162), cytokine receptors, Fc receptors, integrins including αM integrin (CD11b), and activated conformations of Fc receptors and integrins, have been proposed to report cell activation. Variation in eosinophil activation states may be associated with asthma activity. Eosinophil surface proteins proposed to be activation markers, with a particular focus on integrins, and evidence for associations between activation states of blood eosinophils and features of asthma are reviewed here. Partial activation of β1 and β2 integrins on blood eosinophils, reported by monoclonal antibodies (mAbs) N29 and KIM-127, is associated with impaired pulmonary function and airway eosinophilia, respectively, in non-severe asthma. The association with lung function does not occur in severe asthma, presumably due to greater eosinophil extravasation, specifically of activated or pre-activated cells, in severe disease.

Biomarkers in the field of obesity and its related comorbidities

INTRODUCTION

The prevalence of obesity has increased dramatically in the last decades both in children and adults and is now considered a major health problem. It is associated with numerous comorbidities such as hypertension, dyslipidemia, diabetes and subsequent cardiovascular disease (CVD). One of the mechanisms that connect obesity with these comorbidities is the secretion of so-called adipocytokines or adipokines by the adipose tissue itself. Most adipokines with pro-inflammatory properties are overproduced with increasing adiposity, whereas some adipokines with anti-inflammatory or insulin-sensitizing properties, like adiponectin, are decreased. This dysregulation of adipokines production may promote obesity-linked metabolic disorders and CVD. Except adipokines a wide complex network of chemicals balances pro-inflammatory and anti-inflammatory effects.

AREAS COVERED

In this review, we summarize the role of various adipokines and other chemicals associated with obesity and its related cardiometabolic comorbidities, with a special focus on recent evidence showing their potential role as biomarkers whose expression are indicative of obesity and its complications.

EXPERT OPINION

Biomarkers associated with obesity, type 2 diabetes (T2D) and CVD could prove beneficial for early identification, proper treatment and good life assurance. Unfortunately, the complexity of biological pathways interactions is such that further research is necessary before any of these markers could reach an accurate diagnostic value.

Inflammatory responses of airway smooth muscle cells and effects of endothelin receptor antagonism

Endothelin receptor antagonists (ETRAs), authorized for pulmonary hypertension, have failed to prove their utility in chronic lung diseases with corticosteroid-resistant airway inflammation when applied at late disease stages with emphysema/fibrosis. Earlier administration might prove effective by targeting the interaction between airway inflammation and tissue remodeling. We hypothesized that human airway smooth muscle cells (HASMCs) participate in linking inflammation with remodeling and that associated genes become differentially suppressed by ambrisentan (A-receptor selective ETRA) and bosentan (nonselective/dual ETRA). Inflammatory responses of ex vivo-cultivated HASMCs to TNF-α were investigated by whole-genome microarray analyses. qRT-PCR and ELISA were used to test inflammatory and remodeling genes for sensitivity to bosentan and ambrisentan and to investigate differential sensitivities mechanistically. ETRA and corticosteroid effects were compared in HASMCs from patients with chronic obstructive pulmonary disease. TNF-α induced the expression of 18 cytokines/chemokines and five tissue remodeling genes involved in severe, corticosteroid-insensitive asthma, chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, and/or pulmonary hypertension. Thirteen cytokines/chemokines, MMP13, and WISP1 were suppressed by ETRAs. Eight genes had differential sensitivity to bosentan and ambrisentan depending on the endothelin-B receptor impact on transcriptional regulation and mRNA stabilization. Chemokine (C-C motif) ligands 2 and 5, granulocyte macrophage colony-stimulating factor, and MMP13 had increased sensitivity to bosentan or bosentan/dexamethasone combination versus dexamethasone alone. Suppression of cytokine and remodeling gene expression by ETRAs was confirmed in TNF-α-activated human bronchial epithelial cells. HASMCs and human bronchial epithelial cells participate in the interaction of inflammation and tissue remodeling. This interaction is targeted differentially by selective and nonselective ETRAs, which could be used in therapies of chronic lung diseases with corticosteroid-resistant airway inflammation at early disease stages to attenuate inflammation-induced airway remodeling.

Clinical utility of asthma biomarkers: from bench to bedside

Asthma is a chronic disease characterized by airway inflammation, bronchial hyperresponsiveness, and recurrent episodes of reversible airway obstruction. The disease is very heterogeneous in onset, course, and response to treatment, and seems to encompass a broad collection of heterogeneous disease subtypes with different underlying pathophysiological mechanisms. There is a strong need for easily interpreted clinical biomarkers to assess the nature and severity of the disease. Currently available biomarkers for clinical practice - for example markers in bronchial lavage, bronchial biopsies, sputum, or fraction of exhaled nitric oxide (FeNO) - are limited due to invasiveness or lack of specificity. The assessment of markers in peripheral blood might be a good alternative to study airway inflammation more specifically, compared to FeNO, and in a less invasive manner, compared to bronchoalveolar lavage, biopsies, or sputum induction. In addition, promising novel biomarkers are discovered in the field of breath metabolomics (eg, volatile organic compounds) and (pharmaco)genomics. Biomarker research in asthma is increasingly shifting from the assessment of the value of single biomarkers to multidimensional approaches in which the clinical value of a combination of various markers is studied. This could eventually lead to the development of a clinically applicable algorithm composed of various markers and clinical features to phenotype asthma and improve diagnosis and asthma management.

IL-3 and TNFα increase Thymic Stromal Lymphopoietin Receptor (TSLPR) expression on eosinophils and enhance TSLP-stimulated degranulation

BACKGROUND

Thymic stromal lymphopoietin (TSLP) and eosinophils are prominent components of allergic inflammation. Therefore, we sought to determine whether TSLP could activate eosinophils, focusing on measuring the regulation of TSLPR expression on eosinophils and degranulation in response to TSLP, as well as other eosinophil activation responses.

METHODS

Eosinophil mRNA expression of TSLPR and IL-7Rα was examined by real-time quantitative PCR of human eosinophils treated with TNFα and IL-5 family cytokines, and TSLPR surface expression on eosinophils was analyzed by flow cytometry. Eosinophils were stimulated with TSLP (with and without pre-activation with TNFα and IL-3) and evaluated for release of eosinophil derived neurotoxin (EDN), phosphorylation of STAT5, and survival by trypan blue exclusion. A blocking antibody for TSLPR was used to confirm the specificity of TSLP mediated signaling on eosinophil degranulation.

RESULTS

Eosinophil expression of cell surface TSLPR and TSLPR mRNA was upregulated by stimulation with TNFα and IL-3. TSLP stimulation resulted in release of EDN, phosphorylation of STAT5 as well as promotion of viability and survival. TSLP-stimulated eosinophil degranulation was inhibited by a functional blocking antibody to TSLPR. Pre-activation of eosinophils with TNFα and IL-3 promoted eosinophil degranulation at lower concentrations of TSLP stimulation.

CONCLUSIONS

This study demonstrates that eosinophils are activated by TSLP and that eosinophil degranulation in response to TSLP may be enhanced on exposure to cytokines present in allergic inflammation, indicating that the eosinophil has the capacity to participate in TSLP-driven allergic responses.

Interleukin-7 regulates adipose tissue mass and insulin sensitivity in high-fat diet-fed mice through lymphocyte-dependent and independent mechanisms

Although interleukin (IL)-7 is mostly known as a key regulator of lymphocyte homeostasis, we recently demonstrated that it also contributes to body weight regulation through a hypothalamic control. Previous studies have shown that IL-7 is produced by the human obese white adipose tissue (WAT) yet its potential role on WAT development and function in obesity remains unknown. Here, we first show that transgenic mice overexpressing IL-7 have reduced adipose tissue mass associated with glucose and insulin resistance. Moreover, in the high-fat diet (HFD)-induced obesity model, a single administration of IL-7 to C57BL/6 mice is sufficient to prevent HFD-induced WAT mass increase and glucose intolerance. This metabolic protective effect is accompanied by a significant decreased inflammation in WAT. In lymphocyte-deficient HFD-fed SCID mice, IL-7 injection still protects from WAT mass gain. However, IL-7-triggered resistance against WAT inflammation and glucose intolerance is lost in SCID mice. These results suggest that IL-7 regulates adipose tissue mass through a lymphocyte-independent mechanism while its protective role on glucose homeostasis would be relayed by immune cells that participate to WAT inflammation. Our observations establish a key role for IL-7 in the complex mechanisms by which immune mediators modulate metabolic functions.

GM-CSF production by glioblastoma cells has a functional role in eosinophil survival, activation, and growth factor production for enhanced tumor cell proliferation

Medicinal interventions of limited efficacy are currently available for the treatment of glioblastoma multiforme (GBM), the most common and lethal primary brain tumor in adults. The eosinophil is a pivotal immune cell in the pathobiology of atopic disease that is also found to accumulate in certain tumor tissues. Inverse associations between atopy and GBM risk suggest that the eosinophil may play a functional role in certain tumor immune responses. To assess the potential interactions between eosinophils and GBM, we cultured human primary blood eosinophils with two separate human GBM-derived cell lines (A172, U87-MG) or conditioned media generated in the presence or absence of TNF-α. Results demonstrated differential eosinophil adhesion and increased survival in response to coculture with GBM cell lines. Eosinophil responses to GBM cell line-conditioned media included increased survival, activation, CD11b expression, and S100A9 release. Addition of GM-CSF neutralizing Abs to GBM cell cultures or conditioned media reduced eosinophil adhesion, survival, and activation, linking tumor cell-derived GM-CSF to the functions of eosinophils in the tumor microenvironment. Dexamethasone, which has been reported to inhibit eosinophil recruitment and shrink GBM lesions on contrast-enhanced scans, reduced the production of tumor cell-derived GM-CSF. Furthermore, culture of GBM cells in eosinophil-conditioned media increased tumor cell viability, and generation of eosinophil-conditioned media in the presence of GM-CSF enhanced the effect. These data support the idea of a paracrine loop between GM-CSF-producing tumors and eosinophil-derived growth factors in tumor promotion/progression.

Interleukins, from 1 to 37, and interferon-γ: receptors, functions, and roles in diseases

Advancing our understanding of mechanisms of immune regulation in allergy, asthma, autoimmune diseases, tumor development, organ transplantation, and chronic infections could lead to effective and targeted therapies. Subsets of immune and inflammatory cells interact via ILs and IFNs; reciprocal regulation and counter balance among T(h) and regulatory T cells, as well as subsets of B cells, offer opportunities for immune interventions. Here, we review current knowledge about ILs 1 to 37 and IFN-γ. Our understanding of the effects of ILs has greatly increased since the discoveries of monocyte IL (called IL-1) and lymphocyte IL (called IL-2); more than 40 cytokines are now designated as ILs. Studies of transgenic or knockout mice with altered expression of these cytokines or their receptors and analyses of mutations and polymorphisms in human genes that encode these products have provided important information about IL and IFN functions. We discuss their signaling pathways, cellular sources, targets, roles in immune regulation and cellular networks, roles in allergy and asthma, and roles in defense against infections.

The presence of maternal asthma during pregnancy suppresses the placental pro-inflammatory response to an immune challenge in vitro

The mechanisms that contribute to adverse outcomes for the neonate in pregnancies complicated by asthma may be mediated via changes in placental immune function. This study was designed to determine whether the presence of maternal asthma during pregnancy alters the placental pro-inflammatory immune response in vitro. A prospective cohort study of women with asthma (n = 22) and control (n = 11) subjects had placentae collected immediately after delivery. Placental explants were exposed to an immune challenge, lipopolysaccharide, in the presence and absence of cortisol in vitro. Cytokines, glucocorticoid receptor α (GR α) and p38 MAPK protein were measured. Placentae of control pregnancies had an increase in pro-inflammatory cytokine production over a 24 h period. Placentae from pregnancies complicated by maternal asthma had a reduced pro-inflammatory cytokine response to an immune challenge relative to the controls especially in relation to the production of interleukin (IL)-1β and TNFα regardless of fetal sex. Cortisol inhibition of placental cytokine production was dependent on timing of exposure, fetal sex and presence and absence of asthma. GRα and p38 MAPK protein expression did not appear to contribute to differences in response to endotoxin or cortisol. Maternal asthma during pregnancy induces a hyposensitive inflammatory state in the placenta which is regulated by cortisol in a sexually dimorphic manner.

The molecular phenotype of severe asthma in children

BACKGROUND

Although the clinical attributes of severe asthma in children have been well described, the differentiating features of the lower airway inflammatory response are less understood.

OBJECTIVES

We sought to discriminate severe from moderate asthma in children by applying linear discriminant analysis, a supervised method of high-dimensional data reduction, to cytokines and chemokines measured in the bronchoalveolar lavage (BAL) fluid and alveolar macrophage (AM) lysate.

METHODS

Bronchoalveolar lavage fluid was available from 53 children with asthma (severe asthma, n = 31) undergoing bronchoscopy for clinical indications and 30 nonsmoking adults. Twenty-three cytokines and chemokines were measured by using bead-based multiplex assays. Linear discriminant analyses of the BAL fluid and AM analytes were performed to develop predictive models of severe asthma in children.

RESULTS

Although univariate analysis of single analytes did not differentiate severe from moderate asthma in children, linear discriminant analyses allowed for near complete separation of the moderate and severe asthmatic groups. Significant correlations were also noted between several of the AM and BAL analytes measured. In the BAL fluid, IL-13 and IL-6 differentiated subjects with asthma from controls, whereas growth-related oncogene (CXCL1), RANTES (CCL5), IL-12, IFN-gamma, and IL-10 best characterized severe versus moderate asthma in children. In the AM lysate, IL-6 was the strongest discriminator of all the groups.

CONCLUSION

Severe asthma in children is characterized by a distinct airway molecular phenotype that does not have a clear T(H)1 or T(H)2 pattern. Improved classification of children with severe asthma may assist with the development of targeted therapeutics for this group of children who are difficult to treat.

Common gamma-chain-dependent signals confer selective survival of eosinophils in the murine small intestine

Eosinophils are potent effector cells that are recruited to sites of inflammation. However, in some tissues, in particular in the gastrointestinal tract, eosinophils constitute an abundant leukocyte population also under homeostatic conditions. The lack of suitable isolation protocols restricted the analysis of these cells to histological assessment of cell numbers while important aspects of their phenotype, turnover, and functions remain unresolved. In this study, we report a protocol that allows the quantitative isolation of intestinal eosinophils. We characterized small intestinal eosinophils by flow cytometry as SSC(high)CD11b(+)CD11c(+)CCR3(+)Siglec-F(+) cells. Intestinal eosinophils resembled eosinophils isolated from thymus and uterus but differed from eosinophils isolated from lung or blood. Eosinophils in intestine, thymus, and uterus showed in vivo a markedly higher life time compared with eosinophils present in lung and blood measured by incorporation of BrdU. This indicates that under steady-state conditions homeostasis of eosinophils is controlled by regulation of cell survival. Intestinal eosinophils are severely reduced in the intestines of Rag-2/common gamma-chain double-deficient mice but not Rag-2-deficient mice, correlating with differential expression of GM-CSF and CCL11 in both mouse strains. Moreover, under steady-state conditions, intestinal eosinophils constitutively express high levels of the common gamma-chain transcripts compared with lung eosinophils as well as eosinophils present under inflammatory conditions. These observations reveal a hitherto unrecognized diversity in phenotypic and functional properties of eosinophils and suggest that tissue-specific common gamma-chain-dependent signals might profoundly affect eosinophil function and homeostasis.