Protein kinase Cθ controls type 2 innate lymphoid cell and TH2 responses to house dust mite allergen

Analysis of Rare Coding Variants in 470,000 UK Biobank Participants Reveals Genetic Associations With Childhood Asthma Predisposition

Previous studies of genetic contributions to risk of childhood asthma have implicated common variants with small effect sizes. Some studies using exome sequence data have reported associations with rare coding variants having larger effects on risk, notably an analysis of 145,000 subjects which found association with loss of function (LOF) variants in FLG, the gene coding for filaggrin. Here, we report the results of an analysis of rare nonsynonymous and LOF variants, carried out on the full UK Biobank cohort of 470,000 exome-sequenced participants. The phenotype of childhood asthma was defined as reporting asthma with onset before 18. Regression analysis was applied to gene-wise tests for association of LOF and nonsynonymous variants. Forty-five tests using different pathogenicity predictors were applied to the first cohort of 200,000 participants. Subsequently, the 100 genes showing strongest evidence for association were analysed in the second cohort of 270,000 participants, using only the best-performing predictor for each gene. For FLG, separate analyses were carried out for participants with atopic dermatitis. Three genes achieved statistical significance after correction for testing these 100 genes: FLG, IL33 and PRKCQ. The effects on asthma risk and frequencies of variants in different functional categories were characterised for these genes. Damaging coding variants were associated with increased risk of asthma in FLG and IL33 but reduced risk in PRKCQ. FLG LOF variants were also associated with the risk of atopic dermatitis, and their effect on asthma risk was higher in people who reported a diagnosis of atopic dermatitis. Rare coding variants in a small number of genes have important effects on asthma risk. Further study of individual variant effects might elucidate mechanisms of pathogenesis. This research has been conducted using the UK Biobank Resource.

Controlled human exposures to diesel exhaust or particle-depleted diesel exhaust with allergen modulates transcriptomic responses in the lung

The evidence associating traffic-related air pollution (TRAP) with allergic asthma is growing, but the underlying mechanisms for this association remain unclear. The airway epithelium is the primary tissue exposed to TRAP, hence understanding its interactions with TRAP and allergen is important. Diesel exhaust (DE), a paradigm of TRAP, consists of particulate matter (PM) and gases. Modern diesel engines often have catalytic diesel particulate filters to reduce PM output, but these may increase gaseous concentrations, and their benefits on human health cannot be assumed. We conducted a randomized, double-blinded, crossover study using our unique in vivo human exposure system to investigate the effects of DE and allergen co-exposure, with or without particle depletion as a proxy for catalytic diesel particulate filters, on the airway epithelial transcriptome. Participants were exposed for 2 h before an allergen inhalation challenge, with each receiving filtered air and saline (FA-S), filtered air and allergen (FA-A), DE and allergen (DE-A), or particle-depleted DE and allergen (PDDE-A), over four different occasions, each separated by a 4-week washout period. Endobronchial brushings were collected 48 h after each exposure, and total RNA was sequenced. Differentially expressed genes (DEGs) were identified using DESeq2, followed by GO enrichment and pathway analysis. FA-A, DE-A, and PDDE-A exposures significantly modulated genes relative to FA-S, with 462 unique DEGs identified. FA-A uniquely modulated the highest number (↑178, ↓155), followed by DE-A (↑44, ↓23), and then PDDE-A exposure (↑15, ↓2); 6 DEGs (↑4, ↓2) were modulated by all three conditions. Exposure to PDDE-A resulted in modulation of 285 DEGs compared to DE-A exposure, further revealing 26 biological process GO terms, including "cellular response to chemokine" and "inflammatory response". The transcriptional epithelial response to diesel exhaust and allergen co-exposure is enriched in inflammatory mediators, the pattern of which is altered upon particle depletion.

Jiawei Yanghe Decoction attenuate allergic airway inflammation by suppressing group 2 innate lymphoid cells responses

ETHNOPHARMACOLOGICAL RELEVANCE

Jiawei Yanghe Decoction (JWYHD) is modified Yanghe Decoction (YHD). YHD historically utilized as a potent medicinal solution for addressing chronic inflammatory conditions, holds promising therapeutic potential in the treatment of asthma. However, the mechanisms underlying JWYHD's effects on allergic asthma remain unclear.

AIM OF THE STUDY

To investigate the therapeutic effect as well as the underlying mechanisms of JWYHD on asthmatic mice.

MATERIALS AND METHODS

The ovalbumin (OVA)-induced mouse model was utilized, followed by the administration of JWYHD to allergic asthmatic mice. Subsequently, inflammatory cells in the bronchoalveolar lavage fluid (BALF) and lung tissues were conducted. The levels of various cytokines including interleukin (IL)-4, IL-5, IL-13, IL-33, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ in BALF, as well as the total immunoglobulin E (IgE) content in serum, were assessed. Lung function and tissue pathology examinations were performed to assess the protective impacts of JWYHD. The chemical components of JWYHD and its lung prototype compounds (referred to the chemical components present in JWYHD that were observed in the lung) were explored by ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). RNA-seq analysis revealed the regulation mechanisms of JWYHD treating asthma. Furthermore, the effect of JWYHD on type 2 innate lymphoid cells (ILC2s) in asthmatic mice was detected by flow cytometry and Smart-RNA-seq analysis. Then molecular docking analysis was used to show the interaction between identified compounds and key targets.

RESULTS

JWYHD significantly attenuated the airway inflammation of asthmatic mice, reduced the levels of inflammatory cells in BALF, as well the levels of the cytokines IL-4, IL-5, IL-13, IL-33, and TNF-α in BALF and IgE in serum. Airway hyperresponsiveness (AHR) and lung inflammation infiltration were also alleviated by JWYHD. Moreover, RNA-seq analysis revealed that JWYHD attenuated airway inflammation in asthmatic mice via regulating immunity. Flow cytometry confirmed that JWYHD could inhibit ILC2 responses. ILC2 Smart-RNA-seq analysis showed that JWYHD impaired the inflammation reaction-related signaling pathways in ILC2s, and neuropilin-1 (Nrp1), endothelial transcription factor 3 (GATA3) and interleukin 1 receptor like protein 1 (ST2) might be the key targets. The molecular docking analysis investigating the connection between the primary targets and JWYHD's prototype compounds in the lung demonstrated that liquiritin apioside, icariin, glycyrrhizic acid, and uralsaponin B, identified through UPLC-Q-TOF/MS, exhibited significant affinity in binding to the mentioned key targets.

CONCLUSION

Our results suggested that the mechanism of JWYHD in treating asthma might be related to limiting ILC2 responses. Our findings provided some pharmacological evidence for the clinical application of JWYHD in the treatment of asthma.

Off-target pharmacological activity at various kinases: Potential functional and pathological side effects

In drug discovery, during the lead optimization and candidate characterization stages, novel small molecules are frequently evaluated in a battery of in vitro pharmacology assays to identify potential unintended, off-target interactions with various receptors, transporters, ion channels, and enzymes, including kinases. Furthermore, these screening panels may also provide utility at later stages of development to provide a mechanistic understanding of unexpected safety findings. Here, we present a compendium of the most likely functional and pathological outcomes associated with interaction(s) to a panel of 95 kinases based on an extensive curation of the scientific literature. This panel of kinases was designed by AbbVie based on safety-related data extracted from the literature, as well as from over 20 years of institutional knowledge generated from discovery efforts. For each kinase, the scientific literature was reviewed using online databases and the most often reported functional and pathological effects were summarized. This work should serve as a practical guide for small molecule drug discovery scientists and clinical investigators to predict and/or interpret adverse effects related to pharmacological interactions with these kinases.

Black Ginseng Extract Exerts Potentially Anti-Asthmatic Activity by Inhibiting the Protein Kinase Cθ-Mediated IL-4/STAT6 Signaling Pathway

Asthma is a chronic inflammatory lung disease that causes respiratory difficulties. Black ginseng extract (BGE) has preventative effects on respiratory inflammatory diseases such as asthma. However, the pharmacological mechanisms behind the anti-asthmatic activity of BGE remain unknown. To investigate the anti-asthmatic mechanism of BGE, phorbol 12-myristate 13-acetate plus ionomycin (PMA/Iono)-stimulated mouse EL4 cells and ovalbumin (OVA)-induced mice with allergic airway inflammation were used. Immune cells (eosinophils/macrophages), interleukin (IL)-4, -5, -13, and serum immunoglobulin E (IgE) levels were measured using an enzyme-linked immunosorbent assay. Inflammatory cell recruitment and mucus secretion in the lung tissue were estimated. Protein expression was analyzed via Western blotting, including that of inducible nitric oxide synthase (iNOS) and the activation of protein kinase C theta (PKCθ) and its downstream signaling molecules. BGE decreased T helper (Th)2 cytokines, serum IgE, mucus secretion, and iNOS expression in mice with allergic airway inflammation, thereby providing a protective effect. Moreover, BGE and its major ginsenosides inhibited the production of Th2 cytokines in PMA/Iono-stimulated EL4 cells. In EL4 cells, these outcomes were accompanied by the inactivation of PKCθ and its downstream transcription factors, such as nuclear factor of activated T cells (NFAT), nuclear factor kappa B (NF-κB), activator of transcription 6 (STAT6), and GATA binding protein 3 (GATA3), which are involved in allergic airway inflammation. BGE also inhibited the activation of PKCθ and the abovementioned transcriptional factors in the lung tissue of mice with allergic airway inflammation. These results highlight the potential of BGE as a useful therapeutic and preventative agent for allergic airway inflammatory diseases such as allergic asthma.

Hyperprogression of cutaneous T cell lymphoma after anti-PD-1 treatment

BACKGROUNDImmune checkpoint blockade is an emerging treatment for T cell non-Hodgkin's lymphoma (T-NHL), but some patients with T-NHL have experienced hyperprogression with undetermined mechanisms upon anti-PD-1 therapy.METHODSSingle-cell RNA-Seq, whole-genome sequencing, whole-exome sequencing, and functional assays were performed on primary malignant T cells from a patient with advanced cutaneous T cell lymphoma who experienced hyperprogression upon anti-PD-1 treatment.RESULTSThe patient was enrolled in a clinical trial of anti-PD-1 therapy and experienced disease hyperprogression. Single-cell RNA-Seq revealed that PD-1 blockade elicited a remarkable activation and proliferation of the CD4+ malignant T cells, which showed functional PD-1 expression and an exhausted status. Further analyses identified somatic amplification of PRKCQ in the malignant T cells. PRKCQ encodes PKCθ; PKCθ is a key player in the T cell activation/NF-κB pathway. PRKCQ amplification led to high expressions of PKCθ and p-PKCθ (T538) on the malignant T cells, resulting in an oncogenic activation of the T cell receptor (TCR) signaling pathway. PD-1 blockade in this patient released this signaling, derepressed the proliferation of malignant T cells, and resulted in disease hyperprogression.CONCLUSIONOur study provides real-world clinical evidence that PD-1 acts as a tumor suppressor for malignant T cells with oncogenic TCR activation.TRIAL REGISTRATIONClinicalTrials.gov (NCT03809767).FUNDINGThe National Natural Science Foundation of China (81922058), the National Science Fund for Distinguished Young Scholars (T2125002), the National Science and Technology Major Project (2019YFC1315702), the National Youth Top-Notch Talent Support Program (283812), and the Peking University Clinical Medicine plus X Youth Project (PKU2019LCXQ012) supported this work.

See-N-Seq: RNA sequencing of target single cells identified by microscopy via micropatterning of hydrogel porosity

Single cell RNA sequencing has the potential to elucidate transcriptional programs underlying key cellular phenotypes and behaviors. However, many cell phenotypes are incompatible with indiscriminate single cell sequencing because they are rare, transient, or can only be identified by imaging. Existing methods for isolating cells based on imaging for single cell sequencing are technically challenging, time-consuming, and prone to loss because of the need to physically transport single cells. Here, we developed See-N-Seq, a method to rapidly screen cells in microwell plates in order to isolate RNA from specific single cells without needing to physically extract each cell. Our approach involves encapsulating the cell sample in a micropatterned hydrogel with spatially varying porosity to selectively expose specific cells for targeted RNA extraction. Extracted RNA can then be captured, barcoded, reverse transcribed, amplified, and sequenced at high-depth. We used See-N-Seq to isolate and sequence RNA from cell-cell conjugates forming an immunological synapse between T-cells and antigen presenting cells. In the hours after synapsing, we found time-dependent bifurcation of single cell transcriptomic profiles towards Type 1 and Type 2 helper T-cells lineages. Our results demonstrate how See-N-Seq can be used to associate transcriptomic data with specific functions and behaviors in single cells.

Bilirubin represents a negative regulator of ILC2 in allergic airway inflammation

Group 2 innate lymphoid cells (ILC2s) play an important role in allergic airway inflammation. Despite recent advances in defining molecular mechanisms that control ILC2 development and function, the role of endogenous metabolites in the regulation of ILC2s remains poorly understood. Herein, we demonstrated that bilirubin, an end product of heme catabolism, was a potent negative regulator of ILC2s. Bilirubin metabolism was found to be significantly induced during airway inflammation in mouse models. The administration of unconjugated bilirubin (UCB) dramatically suppressed ILC2 responses to interleukin (IL)-33 in mice, including cell proliferation and the production of effector cytokines. Furthermore, UCB significantly alleviated ILC2-driven airway inflammation, which was aggravated upon clearance of endogenous UCB. Mechanistic studies showed that the effects of bilirubin on ILC2s were associated with downregulation of ERK phosphorylation and GATA3 expression. Clinically, newborns with hyperbilirubinemia displayed significantly lower levels of ILC2 with impaired function and suppressed ERK signaling. Together, these findings indicate that bilirubin serves as an endogenous suppressor of ILC2s and might have potential therapeutic value in the treatment of allergic airway inflammation.

Jia-Wei-Yu-Ping-Feng-San Attenuates Group 2 Innate Lymphoid Cell-Mediated Airway Inflammation in Allergic Asthma

The incidence of asthma has increased in recent decades. Although corticosteroids and bronchodilators are used in clinical practice, the control of asthma remains a challenge. Allergic asthma is characterized airway inflammation mediated by type 2 immune response. Group 2 innate lymphoid cells (ILC2s) are an important source of type 2 cytokines IL-5 and IL-13, which contribute to the progress of asthma. Jia-Wei-Yu-Ping-Feng-San (JWYPFS), a traditional Chinese medicine, has been widely used to treat asthma in China. In this study we investigated the mechanisms of JWYPFS in the treatment of asthma, especially the effect on ILC2s important in airway inflammation. Female C57BL/6 mice were sensitized and challenged with OVA to establish a model of allergic asthma. Airway hyperresponsiveness was examined by direct airway resistance analysis. Inflammatory cell counts were determined in bronchoalveolar lavage fluid (BALF). Inflammatory cell infiltration and mucus hypersecretion in lung tissue sections was observed by HE and PAS staining, respectively. The numbers and proportions of ILC2s as well as the ILC2s-related transcription factors GATA3, IRF4, and type 2 cytokines were measured in lung tissue samples. Additionally, ILC2s were collected from mouse lung; ILC2s-related cytokines and GATA3 and IRF4 were evaluated after IL-33-induced activation of ILC2s in vitro. Elevated inflammatory cells, mucus secretion, airway hyperresponsiveness and type 2 cytokines in the OVA-treated asthma group indicated that an allergic asthma model had been established. JWYPFS treatment attenuated airway resistance and reduced inflammatory cells including eosinophils, and inhibited mucus production and type 2 cytokines in these asthmatic mice. Moreover, JWYPFS treatment dramatically decreased the numbers and proportions of ILC2s and the mRNA levels of GATA3 and IRF4. In an in vitro experiment JWYPFS significantly suppressed GATA3, IRF4 and type 2 cytokine expression, including IL-5 and IL-13 in IL-33-stimulated ILC2s. JWYPFS alleviates ILC2s-mediated airway inflammation, suggesting that JWYPFS might be an effective agent to treat allergic asthma.

The Role of Type 2 Innate Lymphoid Cells in Allergic Diseases

Allergic diseases are significant diseases that affect many patients worldwide. In the past few decades, the incidence of allergic diseases has increased significantly due to environmental changes and social development, which has posed a substantial public health burden and even led to premature death. The understanding of the mechanism underlying allergic diseases has been substantially advanced, and the occurrence of allergic diseases and changes in the immune system state are known to be correlated. With the identification and in-depth understanding of innate lymphoid cells, researchers have gradually revealed that type 2 innate lymphoid cells (ILC2s) play important roles in many allergic diseases. However, our current studies of ILC2s are limited, and their status in allergic diseases remains unclear. This article provides an overview of the common phenotypes and activation pathways of ILC2s in different allergic diseases as well as potential research directions to improve the understanding of their roles in different allergic diseases and ultimately find new treatments for these diseases.

Age-of-onset information helps identify 76 genetic variants associated with allergic disease

Risk factors that contribute to inter-individual differences in the age-of-onset of allergic diseases are poorly understood. The aim of this study was to identify genetic risk variants associated with the age at which symptoms of allergic disease first develop, considering information from asthma, hay fever and eczema. Self-reported age-of-onset information was available for 117,130 genotyped individuals of European ancestry from the UK Biobank study. For each individual, we identified the earliest age at which asthma, hay fever and/or eczema was first diagnosed and performed a genome-wide association study (GWAS) of this combined age-of-onset phenotype. We identified 50 variants with a significant independent association (P<3x10-8) with age-of-onset. Forty-five variants had comparable effects on the onset of the three individual diseases and 38 were also associated with allergic disease case-control status in an independent study (n = 222,484). We observed a strong negative genetic correlation between age-of-onset and case-control status of allergic disease (rg = -0.63, P = 4.5x10-61), indicating that cases with early disease onset have a greater burden of allergy risk alleles than those with late disease onset. Subsequently, a multivariate GWAS of age-of-onset and case-control status identified a further 26 associations that were missed by the univariate analyses of age-of-onset or case-control status only. Collectively, of the 76 variants identified, 18 represent novel associations for allergic disease. We identified 81 likely target genes of the 76 associated variants based on information from expression quantitative trait loci (eQTL) and non-synonymous variants, of which we highlight ADAM15, FOSL2, TRIM8, BMPR2, CD200R1, PRKCQ, NOD2, SMAD4, ABCA7 and UBE2L3. Our results support the notion that early and late onset allergic disease have partly distinct genetic architectures, potentially explaining known differences in pathophysiology between individuals.

Structure-Activity Relationships of Baicalein and its Analogs as Novel TSLP Inhibitors

Thymic stromal lymphopoietin (TSLP) plays an important role in the differentiation and proliferation of Th2 cells, resulting in eosinophilic inflammation and numerous allergic diseases. Baicalein (1), a major component of Scutellaria baicalensis, was found to be the first small molecule to block TSLP signaling pathways. It inhibited effectively eosinophil infiltration in house dust mite-induced and ovalbumin-challenged mouse models. Structure-activity relationship studies identified compound 11a, a biphenyl flavanone analog, as a novel human TSLP inhibitor for the discovery and development of new anti-allergic drugs.

Unravelling the roles of innate lymphoid cells in cerebral malaria pathogenesis

Cerebral malaria (CM) is one complication of Plasmodium parasite infection that can lead to strong inflammatory immune responses in the central nervous system (CNS), accompanied by lung inflammation and anaemia. Here, we focus on the role of the innate immune response in experimental cerebral malaria (ECM) caused by blood-stage murine Plasmodium berghei ANKA infection. While T cells are important for ECM pathogenesis, the role of innate lymphoid cells (ILCs) is only emerging. The role of ILCs and non-lymphoid cells, such as neutrophils and platelets, contributing to the host immune response and leading to ECM and human cerebral malaria (HCM) is reviewed.

Nrf2 Suppresses Allergic Lung Inflammation by Attenuating the Type 2 Innate Lymphoid Cell Response

The Keap1-Nrf2 system plays a pivotal role in the oxidative stress response by inducing a number of cytoprotective genes. Under stress, damaged epithelial cells release cytokines that activate type 2 innate lymphoid cells (ILC2s), which mediate the allergic immune response. In this article, we investigated the role of the Keap1-Nrf2 pathway in ILC2 homeostasis and allergic inflammation using Nrf2 knockout mice. ILC2s from Nrf2-deficient mice showed a transient, upregulated IL-33 response and underwent hyperproliferation in response to a combined stimulation of IL-33 with IL-2, IL-7, or TSLP. This enhanced proliferation was correlated with an increased activation of downstream signals, including JAK1, Akt, and Erk1/2. In contrast, activating Nrf2 with a chemical inducer (CDDO-Im) decreased the viability of the wild-type but not of the Nrf2-deficient ILC2s. This effect on viability resembled that exerted by the corticosteroid dexamethasone; however, unlike the latter, the Nrf2-dependent cell death was mediated by neither caspase 3-dependent apoptosis nor necroptosis. Using a mouse intratracheal IL-33 administration allergy model, we found that the activation of Nrf2 by CDDO-Im in vivo decreased the number of pulmonary ILC2s and eosinophils. These findings indicated that Nrf2 is an important regulator of the allergic response by determining the survival and death of ILC2s, and these findings suggest that Nrf2 activation is a potential therapeutic strategy for steroid-resistant allergy alleviation.

STING-dependent sensing of self-DNA drives silica-induced lung inflammation

Silica particles induce lung inflammation and fibrosis. Here we show that stimulator of interferon genes (STING) is essential for silica-induced lung inflammation. In mice, silica induces lung cell death and self-dsDNA release in the bronchoalveolar space that activates STING pathway. Degradation of extracellular self-dsDNA by DNase I inhibits silica-induced STING activation and the downstream type I IFN response. Patients with silicosis have increased circulating dsDNA and CXCL10 in sputum, and patients with fibrotic interstitial lung disease display STING activation and CXCL10 in the lung. In vitro, while mitochondrial dsDNA is sensed by cGAS-STING in dendritic cells, in macrophages extracellular dsDNA activates STING independent of cGAS after silica exposure. These results reveal an essential function of STING-mediated self-dsDNA sensing after silica exposure, and identify DNase I as a potential therapy for silica-induced lung inflammation.

Silica particles induce intereukin-1 (IL-1) response to contribute to lung inflammation, but the underlying mechanism is unclear. Here the authors show that silica induces cell death and release of mitochondria and genomic DNA, which are sensed by STING with or without involving cGAS, respectively, for IL-1 induction and lung inflammation.

Cold Stimuli Facilitate Inflammatory Responses Through Transient Receptor Potential Melastatin 8 (TRPM8) in Primary Airway Epithelial Cells of Asthmatic Mice

Bronchial asthma is a chronic inflammatory airway disease that can be aggravated by cold air. However, its mechanism remains largely unknown. As a thermo-sensing cation channel, transient receptor potential melastatin 8 (TRPM8) can be activated by cold stimuli (8-22 °C) and cooling agents. Whereas TRPM8 activation leads to enhanced expression of inflammatory cytokines and mucus hypersecretion in human bronchial epithelial cell lines, no previous study has examined its role in regulating the cold-induced inflammatory responses and its mechanism in asthmatic airway epithelium. Airway epithelial cells were isolated from asthma model mice and exposed to low temperature (18 °C). The TRPM8 overexpression plasmid and siRNA lentivirus were transfected to up- or downregulate the TRPM8 level. The expression of mRNAs of inflammatory cytokines was tested using real-time reverse transcription-polymerase chain reaction (RT-PCR). The activities of phosphorylated protein kinase C (PKC) and phosphorylated inhibitor of nuclear factor kappa B (IκB) were measured using the immunofluorescence assay. The expression of mRNAs of inflammatory cytokines [interleukin (IL)-1β, IL-4, IL-6, IL-8, IL-10, IL-13, granulocyte macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor (TNF)-α] increased significantly under cold conditions, which was boosted after TRPM8 overexpression and augmented further in the presence of PKC inhibitor, calphostin C. However, the downregulation of TRPM8 and nuclear factor kappa B (NF-κB) impaired the transcription of these cytokine genes. In addition, the phosphorylated PKC and phosphorylated IκB were activated by cold stimuli. Moreover, the expression of phosphorylated IκB protein improved in the presence of TRPM8, while disruption with the TRPM8 gene or TRPM8 antagonist prohibited the activation of IκB. Cold air could induce inflammatory responses through the TRPM8-mediated PKC/NF-κB signal pathway in primary airway epithelial cells of asthmatic mice.

Advances in mechanisms of allergic disease in 2017

This review highlights advances in mechanisms of allergic disease, particularly type 2 innate lymphoid cells, T_H2 lymphocytes, B cells, dendritic cells, microbiome and barrier function, eosinophils, and mast cells. During the last year, considerable progress has been made in the further characterization of type 2 inflammation controlled by both adaptive (T_H2) and type 2 innate lymphoid effector cells. New pathways of lymphocyte activation, trafficking, and recruitment and effector cell mechanisms have been discovered. The plasticity of lymphocyte effector cell responses is another area in which major progress has been achieved. Accumulating evidence will influence both our understanding of allergic disease and our efforts for allergy prevention and treatment.

The probiotic strain Escherichia coli Nissle 1917 prevents papain-induced respiratory barrier injury and severe allergic inflammation in mice

Allergic asthma is characterized by a strong Th2 and Th17 response with inflammatory cell recruitment, airways hyperreactivity and structural changes in the lung. The protease allergen papain disrupts the airway epithelium triggering a rapid eosinophilic inflammation by innate lymphoid cell type 2 (ILC2) activation, leading to a Th2 immune response. Here we asked whether the daily oral administrations of the probiotic Escherichia coli strain Nissle 1917 (ECN) might affect the outcome of the papain protease induced allergic lung inflammation in BL6 mice. We find that ECN gavage significantly prevented the severe allergic response induced by repeated papain challenges and reduced lung inflammatory cell recruitment, Th2 and Th17 response and respiratory epithelial barrier disruption with emphysema and airway hyperreactivity. In conclusion, ECN administration attenuated severe protease induced allergic inflammation, which may be beneficial to prevent allergic asthma.

Muscle Expression of SOD1G93A Triggers the Dismantlement of Neuromuscular Junction via PKC-Theta

AIM

Neuromuscular junction (NMJ) represents the morphofunctional interface between muscle and nerve. Several chronic pathologies such as aging and neurodegenerative diseases, including muscular dystrophy and amyotrophic lateral sclerosis, display altered NMJ and functional denervation. However, the triggers and the molecular mechanisms underlying the dismantlement of NMJ remain unclear.

RESULTS

Here we provide evidence that perturbation in redox signaling cascades, induced by muscle-specific accumulation of mutant SOD1^G93A in transgenic MLC/SOD1^G93A mice, is causally linked to morphological alterations of the neuromuscular presynaptic terminals, high turnover rate of acetylcholine receptor, and NMJ dismantlement. The analysis of potential molecular mechanisms that mediate the toxic activity of SOD1^G93A revealed a causal link between protein kinase Cθ (PKCθ) activation and NMJ disintegration.

INNOVATION

The study discloses the molecular mechanism that triggers functional denervation associated with the toxic activity of muscle SOD1^G93A expression and suggests the possibility of developing a new strategy to counteract age- and pathology-associated denervation based on pharmacological inhibition of PKCθ activity.

CONCLUSIONS

Collectively, these data indicate that muscle-specific accumulation of oxidative damage can affect neuromuscular communication and induce NMJ dismantlement through a PKCθ-dependent mechanism. Antioxid. Redox Signal. 28, 1105-1119.

Nitric Oxide Signaling in T Cell-Mediated Immunity

Nitric oxide (NO) is a key messenger in the pathogenesis of inflammation, linking innate and adaptive immunity. By targeting signaling molecules, NO from inducible NO synthase (iNOS) and endothelial (e)NOS affects T helper cell differentiation and the effector functions of T lymphocytes, and is a potential target for therapeutic manipulation. In this review we discuss the regulatory actions exerted by NO on T cell functions, focusing on S-nitrosylation as an important post-translational modification by which NO acts as a signaling molecule during T cell-mediated immunity. We also present recent findings showing novel mechanisms through which NO regulates the activation of human T cells, and consider their potential in strategies to treat tumoral, allergic, and autoimmune diseases.

Neutralization of either IL-17A or IL-17F is sufficient to inhibit house dust mite induced allergic asthma in mice

T helper (Th)17 immune response participates in allergic lung inflammation and asthma is reduced in the absence of interleukin (IL)-17 in mice. Since IL-17A and IL-17F are induced and bind the shared receptor IL-17RA, we asked whether both IL-17A and IL-17F contribute to house dust mite (HDM) induced asthma. We report that allergic lung inflammation is attenuated in absence of either IL-17A or IL-17F with reduced airway hyperreactivity, eosinophilic inflammation, goblet cell hyperplasia, cytokine and chemokine production as found in absence of IL-17RA. Furthermore, specific antibody neutralization of either IL-17A or IL-17F given during the sensitization phase attenuated allergic lung inflammation and airway hyperreactivity. In vitro activation by HDM of primary dendritic cells revealed a comparable induction of CXCL1 and IL-6 expression and the response to IL-17A and IL-17F relied on IL-17RA signaling via the adaptor protein act1 in fibroblasts. Therefore, HDM-induced allergic respiratory response depends on IL-17RA via act1 signaling and inactivation of either IL-17A or IL-17F is sufficient to attenuate allergic asthma in mice.

Type two innate lymphoid cells: the Janus cells in health and disease

Innate lymphoid cells are functionally diverse subsets of immune cells including the conventional natural killer cells, lymphoid tissue inducers, type 1, 2, and 3 with significant roles in immunity and pathogenesis of inflammatory diseases. Type 2 innate lymphoid cells (ILC2s) resemble type 2 helper (Th2) cells in cytokine production and contribute to anti-helminth immunity, maintaining mucosal tissue integrity, and adipose tissue browning. ILC2s play important roles in the pathogenesis of allergic diseases and asthma. Studying the pathways of activation and regulation of ILC2s are currently a priority for giving a better understanding of pathogenesis of diseases with immunological roots. Recently, our laboratory and others have shown several pathways of regulation of ILC2s by co-stimulatory molecules such as ICOS, regulatory T cells and by compounds such as nicotine. In this review, we summarize the current understanding of the mechanisms of activation and regulation of ILC2s and the role of these cells in health and disease.