Eosinophil Chemokine Research Articles

Interleukin-19 enhances eosinophil infiltration through upregulation of epithelium-derived RANTES expression via the ERK/NF-κB signalling pathway in patients with eosinophilic CRSwNP.

The recurrence rate of chronic rhinosinusitis with nasal polyps (CRSwNP) is positively correlated with eosinophil infiltration. Increased interleukin (IL)-19 and eosinophil chemokine RANTES levels have been reported in patients with CRSwNP. This study aimed to clarify the role of IL-19 in mediating RANTES expression and eosinophilic infiltration in eosinophilic CRSwNP (Eos CRSwNP). Nasal tissue samples were obtained from patients with CRSwNP and controls. The expression of IL-19, its receptors, ECP, and RANTES in tissues was investigated. Primary human nasal epithelial cells (HNECs) and nasal polyp tissue blocks were cultured, then stimulated by IL-19; ERK phosphorylation, NF-κB pathway activation, RANTES level, eosinophils migration and infiltration were detected using RT-qPCR, ELISA, western blotting, HE, immunohistochemistry, immunofluorescence staining, confocal microscopy, and transwell migration assay. The expression of IL-19 and its receptors (IL-20R1/IL-20R2), eosinophil cationic protein, and RANTES in nasal tissues from patients with Eos CRSwNP was significantly increased compared to that in non-Eos CRSwNP and control subjects. IL-19 co-localized with RANTES in nasal tissues and significantly elevated RANTES expression in HNECs. IL-19-blocking antibody and siRNA knockdown of IL-20R1 ameliorated the effect of IL-19 on RANTES secretion in HNECs. Moreover, IL-19-induced RANTES upregulation was associated with the activation of the ERK and NF-κB pathways. NF-κB activation was mediated by the ERK pathway in IL-19-treated HNECs, and IL-19 enhanced eosinophil infiltration in nasal polyp tissue blocks. Our findings indicate that IL-19 promotes RANTES expression via the ERK/NF-κB pathway in HNECs and is implicated in eosinophil infiltration in patients with Eos CRSwNP.

Evaluation of the Correlation Between Nasal Secretion ECP-MPO Test Papers and Immune Markers in Subcutaneous Immunotherapy of Dust Mites.

Up to now, there is no generally accepted biomarker to indicate the clinical response of immunotherapy. This study mainly analyzed the correlation between eosinophil cationic protein-myeloperoxidase (ECP-MPO) test papers and other immunotherapy indices in subcutaneous immunotherapy of dust mites and to explore whether the test paper can be used as an auxiliary index to quickly evaluate the efficacy of immunotherapy. This study included 53 participants who received subcutaneous immunotherapy at the allergy clinic of Renmin Hospital of Wuhan University and 28 control participants. Six visits were conducted during a prospective study over one year. The results of the ECP-MPO test paper, nasal secretion eosinophil smear and count, nasal secretion ECP concentration, and clinical symptom scores were collected during five follow-up visits after the start of subcutaneous immunotherapy. Th1/Th2/Th17 cytokines, chemokines, IgE, IgG4 against dust mite components, and ECP concentrations were detected in the serum of participants at baseline, six months, and one year after subcutaneous immunotherapy. The ECP test paper is not only easy to operate, but also can effectively and quickly detect the concentrations of ECP in the nasal secretion and diagnose allergic rhinitis. Symptom score is an important index for evaluating clinical immune efficacy, during subcutaneous immunotherapy, the ECP test paper showed a positive correlation with the symptom score. Simultaneously, during immunotherapy, the changes in the chromogenic grading of the test paper were synchronized with the changes in inflammatory cytokines and eosinophilic chemokines in Th2 cells of serum dust mite IgE. The sIgG4 against dust mites weakly negatively correlated with the concentration of ECP in nasal secretions and the color classification of the ECP test paper. The ECP-MPO test paper has a certain correlation with subcutaneous immunotherapy markers of allergic rhinitis, indicating that the ECP test paper may become an auxiliary biomarker to replace other complex laboratory tests.

Role of the protease-activated receptor-2 (PAR2) in the exacerbation of house dust mite-induced murine allergic lung disease by multi-walled carbon nanotubes

BackgroundPulmonary exposure to multi-walled carbon nanotubes (MWCNTs) has been reported to exert strong pro-inflammatory and pro-fibrotic adjuvant effects in mouse models of allergic lung disease. However, the molecular mechanisms through which MWCNTs exacerbate allergen-induced lung disease remain to be elucidated. We hypothesized that protease-activated receptor 2 (PAR2), a G-protein coupled receptor previously implicated in the pathogenesis of various diseases including pulmonary fibrosis and asthma, may play an important role in the exacerbation of house dust mite (HDM) allergen-induced lung disease by MWCNTs.MethodsWildtype (WT) male C57BL6 mice and Par2 KO mice were exposed to vehicle, MWCNTs, HDM extract, or both via oropharyngeal aspiration 6 times over a period of 3 weeks and were sacrificed 3-days after the final exposure (day 22). Bronchoalveolar lavage fluid (BALF) was harvested to measure changes in inflammatory cells, total protein, and lactate dehydrogenase (LDH). Lung protein and RNA were assayed for pro-inflammatory or profibrotic mediators, and formalin-fixed lung sections were evaluated for histopathology.ResultsIn both WT and Par2 KO mice, co-exposure to MWCNTs synergistically increased lung inflammation assessed by histopathology, and increased BALF cellularity, primarily eosinophils, as well as BALF total protein and LDH in the presence of relatively low doses of HDM extract that alone produced little, if any, lung inflammation. In addition, both WT and par2 KO mice displayed a similar increase in lung Cc1-11 mRNA, which encodes the eosinophil chemokine CCL-11, after co-exposure to MWCNTs and HDM extract. However, Par2 KO mice displayed significantly less airway fibrosis as determined by quantitative morphometry compared to WT mice after co-exposure to MWCNTs and HDM extract. Accordingly, at both protein and mRNA levels, the pro-fibrotic mediator arginase 1 (ARG-1), was downregulated in Par2 KO mice exposed to MWCNTs and HDM. In contrast, phosphorylation of the pro-inflammatory transcription factor NF-κB and the pro-inflammatory cytokine CXCL-1 was increased in Par2 KO mice exposed to MWCNTs and HDM.ConclusionsOur study indicates that PAR2 mediates airway fibrosis but not eosinophilic lung inflammation induced by co-exposure to MWCNTs and HDM allergens.

Chronic HDM exposure shows time-of-day and sex-based differences in inflammatory response associated with lung circadian clock disruption

Circadian rhythms and sex differences are involved in the pathophysiology of asthma. Yet, there are no reports that simultaneously address the role of the circadian clock and sex-based differences in chronic house dust mite (HDM)-induced asthma. Here, we sought to determine if chronic HDM exposure during the resting phase (zeitgeber time: ZT0/6:00 a.m.) versus the active phase (ZT12/6:00 p.m.) differentially affects the circadian clock and alters asthma pathobiology in female and male mice. HDM exposure at ZT12 exaggerated infiltration of eosinophil subtypes and associated chemokines in females compared to males. Furthermore, HDM exposure augmented eosinophil chemokines, Th2 gene expression and cytokine release, and humoral immune response in females compared to males at ZT12. Concurrently, histopathological evaluation confirmed increased airway inflammation at ZT12 in both females and males. Overall, we showed a time-of-day response and sex-based differences in HDM-induced exaggerated asthmatic phenotypes (inflammation/remodeling) and circadian clock disruption in females compared to males.

Abnormal adenosine metabolism of neutrophils inhibits airway inflammation and remodeling in asthma model induced by Aspergillus fumigatus

BackgroundNeutrophils consume a large amount of energy when performing their functions. Compared with other white blood cells, neutrophils contain few mitochondria and mainly rely on glycolysis and gluconeogenesis to produce ATP. The inflammatory site is hypoxic and nutrient poor. Our aim is to study the role of abnormal adenosine metabolism of neutrophils in the asthmatic airway inflammation microenvironment.MethodIn this study, an asthma model was established by intratracheal instillation of Aspergillus fumigatus extract in Ecto-5'-Nucleotidase (CD73) gene–knockout and wild-type mice. Multiple analyses from bronchoalveolar lavage fluid (BALF) were used to determine the levels of cytokines and chemokines. Immunohistochemistry was used to detect subcutaneous fibrosis and inflammatory cell infiltration. Finally, adenosine 5’-(α, β-methylene) diphosphate (APCP), a CD73 inhibitor, was pumped subcutaneously before Aspergillus attack to observe the infiltration of inflammatory cells and subcutaneous fibrosis to clarify its therapeutic effect.ResultPAS staining showed that CD73 knockout inhibited pulmonary epithelial cell proliferation and bronchial fibrosis induced by Aspergillus extract. The genetic knockdownof CD73 significantly reduced the production of Th2 cytokines, interleukin (IL)-4, IL-6, IL-13, chemokine (C–C motif) ligand 5 (CCL5), eosinophil chemokine, neutrophil IL-17, and granulocyte colony-stimulating factor (G-CSF). In addition, exogenous adenosine supplementation increased airway inflammation. Finally, the CD73 inhibitor APCP was administered to reduce inflammation and subcutaneous fibrosis.ConclusionElevated adenosine metabolism plays an inflammatory role in asthma, and CD73 could be a potential therapeutic target for asthma.

Myeloid Bmal1 deletion suppresses the house dust mite-induced chronic lung allergy.

Asthma is the chronic pulmonary inflammatory response that could lead to respiratory failure when allergic reactions exacerbate. It is featured by type 2 immunity with eosinophilic inflammation, mucus, and IgE production, and Th2 cytokine secretion upon repeated challenge of allergens. The symptom severity of asthma displays an apparent circadian rhythm with aggravated airway resistance in the early morning in patients. Bmal1 is the core regulator of the circadian clock, while the regulatory role of Bmal1 in asthma remains unclear. Here, we investigate whether the myeloid Bmal1 is involved in the pathogenesis of house dust mite (HDM)-induced lung allergy. We found that knockdown of Bmal1 in macrophages suppressed the time-of-day variance of the eosinophil infiltration in the alveolar spaces in chronic asthmatic mice. This was accompanied by decreased bronchial mucus production, collagen deposition, and HDM-specific IgE production. However, the suppression effects of myeloid Bmal1 deletion did not alter the allergic responses in short-term exposure to HDM. The transcriptome profile of alveolar macrophages (AMs) showed that Bmal1-deficient AMs have enhanced phagocytosis and reduced production of allergy-mediating prostanoids thromboxane A2 and prostaglandin F2α synthesis. The attenuated thromboxane A2 and prostaglandin F2α may lead to less induction of the eosinophil chemokine Ccl11 expression in bronchial epithelial cells. In summary, our study demonstrates that Bmal1 ablation in macrophages attenuates eosinophilic inflammation in HDM-induced chronic lung allergy, which involves enhanced phagocytosis and reduced prostanoid secretion.

Bullous pemphigoid-What do we know about the most recent therapies?

Bullous pemphigoid (BP) is the most common subtype of autoimmune blistering diseases that primarily affects the elderly and is classically defined by the presence of IgG and/or complement C3 against the BP180 and BP230 hemidesmosome proteins. However, most recent studies have introduced the role of specific eosinophil receptors and chemokine mediators in the pathogenesis of BP which are helpful in identifying new targets for future treatments. This review will focus on the involvement of eosinophils in BP, including the processes that lead to their recruitment, activation, and regulation. Subsequently, covering new therapeutic options in relation to the role of eosinophils. Eotaxin enhances the recruitment of eosinophils in BP, with CCR3 chemoreceptor that is expressed on eosinophils being identified as a key binding site for eotaxin-1. The pathogenic role of IgE and IL-4 in BP is corroborated by successful treatments with Omalizumab and Dupilumab, respectively. IL-5, IL-17 and IL-23 inhibitors may be effective given their roles in promoting eosinophilia. Further research into inhibitors of eotaxin, IL-4, IL-5, IL-17, IL-23, CCR3, and specific complement factors are warranted as preliminary studies have largely identified success in treating BP with these agents. Learning from novel treatments for other IgG-mediated autoimmune diseases may be beneficial.

Early Th2 inflammation in the upper respiratory mucosa as a predictor of severe COVID-19 and modulation by early treatment with inhaled corticosteroids: a mechanistic analysis

BackgroundCommunity-based clinical trials of the inhaled corticosteroid budesonide in early COVID-19 have shown improved patient outcomes. We aimed to understand the inflammatory mechanism of budesonide in the treatment of early COVID-19.MethodsThe STOIC trial was a randomised, open label, parallel group, phase 2 clinical intervention trial where patients were randomly assigned (1:1) to receive usual care (as needed antipyretics were only available treatment) or inhaled budesonide at a dose of 800 μg twice a day plus usual care. For this experimental analysis, we investigated the nasal mucosal inflammatory response in patients recruited to the STOIC trial and in a cohort of SARS-CoV-2-negative healthy controls, recruited from a long-term observational data collection study at the University of Oxford. In patients with SARS-CoV-2 who entered the STOIC study, nasal epithelial lining fluid was sampled at day of randomisation (day 0) and at day 14 following randomisation, blood samples were also collected at day 28 after randomisation. Nasal epithelial lining fluid and blood samples were collected from the SARS-CoV-2 negative control cohort. Inflammatory mediators in the nasal epithelial lining fluid and blood were assessed for a range of viral response proteins, and innate and adaptive response markers using Meso Scale Discovery enzyme linked immunoassay panels. These samples were used to investigate the evolution of inflammation in the early COVID-19 disease course and assess the effect of budesonide on inflammation.Findings146 participants were recruited in the STOIC trial (n=73 in the usual care group; n=73 in the budesonide group). 140 nasal mucosal samples were available at day 0 (randomisation) and 122 samples at day 14. At day 28, whole blood was collected from 123 participants (62 in the budesonide group and 61 in the usual care group). 20 blood or nasal samples were collected from healthy controls. In early COVID-19 disease, there was an enhanced inflammatory airway response with the induction of an anti-viral and T-helper 1 and 2 (Th1/2) inflammatory response compared with healthy individuals. Individuals with COVID-19 who clinically deteriorated (ie, who met the primary outcome) showed an early blunted respiratory interferon response and pronounced and persistent Th2 inflammation, mediated by CC chemokine ligand (CCL)-24, compared with those with COVID-19 who did not clinically deteriorate. Over time, the natural course of COVID-19 showed persistently high respiratory interferon concentrations and elevated concentrations of the eosinophil chemokine, CCL-11, despite clinical symptom improvement. There was persistent systemic inflammation after 28 days following COVID-19, including elevated concentrations of interleukin (IL)-6, tumour necrosis factor-α, and CCL-11. Budesonide treatment modulated inflammation in the nose and blood and was shown to decrease IL-33 and increase CCL17. The STOIC trial was registered with ClinicalTrials.gov, NCT04416399.InterpretationAn initial blunted interferon response and heightened T-helper 2 inflammatory response in the respiratory tract following SARS-CoV-2 infection could be a biomarker for predicting the development of severe COVID-19 disease. The clinical benefit of inhaled budesonide in early COVID-19 is likely to be as a consequence of its inflammatory modulatory effect, suggesting efficacy by reducing epithelial damage and an improved T-cell response.FundingOxford National Institute of Health Research Biomedical Research Centre and AstraZeneca.

Analysis of Nano-Silver Application in Nasosinusitis and Its Effect on Eotaxin

Nasosinusitis (NA) is a severe inflammatory disease. In recent years, NA’s morbidity and its threat to patients is becoming increasingly serious. Clinically, it is considered that NA recurrence and refractoriness is due to eosinophil (EO) proliferation. Nanotechnology improvement and application is a breakthrough in diagnosing and treating clinical diseases. Among which, nano-silver (NNS) technology is consistent with effective NA treatment, but there is no reliable research demonstrating this. In this study, inflammatory factors, EO chemokines, and epidermal growth factors (EGF) in NNS-treated NA mice were analyzed to determine whether NNS had a potential therapeutic effect on NA. The results showed the clinical NA symptom score in mice decreased (P <0.05). Inflammatory factors in nasal lavage fluid (NLF), as well as NF-κB and eotaxin in the maxillary sinus mucosa were inhibited (P <0.05). Finally, EGF and epidermal growth factor receptor increased (P <0.05). These data demonstrate that NNS is an effective NA treatment. NNS may be able to reduce the cell inflammation occurrence and development by inhibiting EO chemokine expression, and promoting certain repair programs to the damaged nasal mucosa. There, NNS may become a feasible scheme for future NA treatment.

Critical Adjuvant Influences on Preventive Anti-Metastasis Vaccine Using a Structural Epitope Derived from Membrane Type Protease PRSS14.

We tested how adjuvants effect in a cancer vaccine model using an epitope derived from an autoactivation loop of membrane-type protease serine protease 14 (PRSS14; loop metavaccine) in mouse mammary tumor virus (MMTV)-polyoma middle tumor-antigen (PyMT) system and in 2 other orthotopic mouse systems. Earlier, we reported that loop metavaccine effectively prevented progression and metastasis regardless of adjuvant types and TH types of hosts in tail-vein injection systems. However, the loop metavaccine with Freund's complete adjuvant (CFA) reduced cancer progression and metastasis while that with alum, to our surprise, were adversely affected in 3 tumor bearing mouse models. The amounts of loop peptide specific antibodies inversely correlated with tumor burden and metastasis, meanwhile both TH1 and TH2 isotypes were present regardless of host type and adjuvant. Tumor infiltrating myeloid cells such as eosinophil, monocyte, and neutrophil were asymmetrically distributed among 2 adjuvant groups with loop metavaccine. Systemic expression profiling using the lymph nodes of the differentially immunized MMTV-PyMT mouse revealed that adjuvant types, as well as loop metavaccine can change the immune signatures. Specifically, loop metavaccine itself induces TH2 and TH17 responses but reduces TH1 and Treg responses regardless of adjuvant type, whereas CFA but not alum increased follicular TH response. Among the myeloid signatures, eosinophil was most distinct between CFA and alum. Survival analysis of breast cancer patients showed that eosinophil chemokines can be useful prognostic factors in PRSS14 positive patients. Based on these observations, we concluded that multiple immune parameters are to be considered when applying a vaccine strategy to cancer patients.

Chronic Rhinosinusitis without Nasal Polyps in Asian Patients Shows Mixed Inflammatory Patterns and Neutrophil-Related Disease Severity

Chronic rhinosinusitis (CRS) shows heterogeneous immunologic features. Western studies revealed that CRS without nasal polyps (CRSsNP) showed a predominantly type 1 immune response and CRS with nasal polyps (CRSwNP) was characterized by type 2 immune response; however, the detailed immunologic profile of CRSsNP in Asian patients has not been thoroughly investigated. Therefore, we investigated the inflammatory endotypes of CRSsNP in Asian patients. Patients with CRSsNP (N = 57), patients with CRSwNP (N = 13), and a control group (N = 10), who underwent endoscopic sinus surgery, were enrolled; uncinate process (UP) tissues were harvested from all patients. Homogenates were prepared from the UP of each group, and immunologic profiles were analyzed, including major cytokines (32 inflammatory mediators). When comparing the UPs between groups, CRSsNP patients showed higher levels of Th2 cytokines (IL-4 and IL-13), eosinophilic chemokines (CCL-11 and CCL-24), ECP, and total IgE expression than control subjects. In addition, several neutrophilic markers (IL-1α, IL-6, IL-8, CXCL-1, CXCL-2, and MPO), IL-17A, IL-22, and TNF-α were dominant in CRSsNP patients. Among these inflammatory mediators, IL-17A showed higher expression levels in CRSsNP patients than in the control group and CRSwNP patients. However, IFN-γ expression was not significantly elevated in CRSsNP patients. The levels of neutrophil-associated cytokines were well correlated with each other; of which, CXCL2, IL-8, and MMP-9/TIMP-1 levels were significantly correlated with disease extent (r = 0.338, r = 0.317, and r = 0.424, respectively). However, the levels of eosinophil-associated cytokines showed little correlation with each other and were not correlated with disease extent. Our study revealed that Asian CRSsNP patients showed a mixed (types 2 and 17) immune response, but neutrophil-related markers were dominant and associated with disease extent. Knowledge of this immunologic feature may help clinicians make better individual treatment decisions for Asian CRSsNP patients.

Eosinophils: Old Players in a New Game.

Eosinophils are terminal polymorphonuclear cells with a high number of cytoplasmic granules that originate in bone marrow. Some are exosomes, which contain multiple molecules, such as specific eosinophilic proteins, cytokines, chemokines, enzymes, and lipid mediators that contribute to the effector role of these cells. Moreover, exosomes present a large number of receptors that allow them to interact with multiple cell types. Eosinophils play an important role in defense against infestations and are a key element in asthma and allergic diseases. Eosinophils are recruited to the inflamed area in response to stimuli, modulating the immune response through the release to the extracellular medium of their granule-derived content. Various mechanisms of degranulation have been identified. Polymorphonuclear leukocytes contain multivesicular bodies that generate exosomes that are secreted into the extracellular environment. Eosinophilic exosomes participate in multiple processes and mechanisms. Eosinophils participate actively in asthma and are hallmarks of the disease. The cells migrate to the inflammatory focus and contribute to epithelial damage and airway remodeling. Given their relevance in this pathology, new therapeutic tools have been developed that target mainly eosinophils and their receptors. In this manuscript, we provide a global, updated vision of the biology of eosinophils and the role of eosinophils in respiratory diseases, particularly asthma. We also summarize asthma treatments linked to eosinophils and new therapeutic strategies based on biological products in which eosinophils and their receptors are the main targets.

Eosinophil Chemokines and Clara Cell Protein 16 Production in Nasal Mucosa of Patients with Persistent Allergic Rhinitis.

Eotaxin-2 and regulated on activation normal T cell expressed and secreted (RANTES) are involved in the eosinophil trafficking in patients with persistent allergic rhinitis (PAR). Clara cell protein 16 (CC16) is an anti-inflammatory protein mainly produced by the epithelial non-ciliated Clara cells. The aim of this study was to investigate the production of CC16 and chemokines eotaxin-2 and RANTES in nasal mucosa of patients with PAR. Twenty-one PAR patients and 20 healthy participants were included. CC16, eotaxin-2, and RANTES concentrations were measured in nasal secretions. PAR patients were administered fluticasone furoate nasal spray (220 μg daily for 14 days). We performed nasal cytology, symptom score assessment, and inflammatory mediator detection before and after the therapy. The level of CC16 in patients with PAR was lower than in the healthy subjects (p=0.023). The eosinophil counts and local concentrations of eotaxin-2 and RANTES were higher in patients with PAR in comparison with controls (p=0.008, p=0.001, p=0.031, respectively). We also found a negative correlation between the CC16 and eotaxin-2 levels in nasal secretions of PAR patients (r=-0.492, p=0.023). After corticosteroid therapy, the patients with PAR had lower nasal symptoms, eosinophil counts, eotaxin-2, and RANTES levels and higher levels of CC16 (p<0.001 for all parameters). Our results suggest the presence of a negative correlation in production of CC16 and eotaxin-2 in nasal mucosa of patients with PAR. Intranasal corticosteroids have a suppressive effect on mucosal eosinophilic inflammation and a stimulating effect on local CC16 production.

Catalpol alleviates ovalbumin-induced asthma in mice: Reduced eosinophil infiltration in the lung

BackgroundRadix Rehmanniae Preparata is a traditional Chinese herbal medicine used to treat asthma, and catalpol is one of the main active ingredients in this herb. In the present study, the effects of catalpol on asthma and the underlying mechanism were explored. MethodsMice with ovalbumin (OVA)-induced asthma were given 5 or 10mg/kg catalpol from Day 15 to Day 28 (intraperitoneal injection). Histopathologic changes were detected by Hematoxylin and Eosin staining and Periodic Acid Schiff staining. The levels of IgE, interleukin (IL)-4, IL-5 and eotaxin were measured by ELISA. The numbers of lymphocytes, monocytes, basophils and eosinophils in the bronchoalveolar lavage fluid were determined by Wright-Giemsa staining. The expression and distribution of eotaxin and C-C chemokine receptor 3 (CCR3) were detected by immunohistochemistry and immunofluorescence. The expression of interleukin-5 receptor α (IL-5Rα) was detected by Western blot assay. ResultsCatalpol inhibited OVA-induced inflammation and IgE secretion in the lung. OVA-induced type 2 inflammation was suppressed by catalpol as evidenced by decreased levels of IL-4 and IL-5. Moreover, catalpol inhibited the aberrant eosinophil infiltration in the lungs, and also suppressed OVA-induced elevation of eosinophil chemokine eotaxin and its receptor CCR3. In addition, IL-5Rα expression in the bone marrow cells derived from catalpol-treated asthmatic mice was lower than that from the untreated asthmatic mice. ConclusionOur study demonstrated that catalpol attenuated OVA-induced asthma and inhibit the infiltration of inflammatory cells, especially eosinophils, into the lung. This study suggests that catalpol may become a promising drug for the treatment of asthma.

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

Protein kinase C (PKC) θ, a serine/threonine kinase, is involved in TH2 cell activation and proliferation. Type 2 innate lymphoid cells (ILC2s) resemble TH2 cells and produce the TH2 cytokines IL-5 and IL-13 but lack antigen-specific receptors. The mechanism by which PKC-θ drives innate immune cells to instruct TH2 responses in patients with allergic lung inflammation remains unknown. We hypothesized that PKC-θ contributes to ILC2 activation and might be necessary for ILC2s to instruct the TH2 response. PRKCQ gene expression was assessed in innate lymphoid cell subsets purified from human PBMCs and mouse lung ILC2s. ILC2 activation and eosinophil recruitment, TH2-related cytokine and chemokine production, lung histopathology, interferon regulatory factor 4 (IRF4) mRNA expression, and nuclear factor of activated T cells (NFAT1) protein expression were determined. Adoptive transfer of ILC2s from wild-type mice was performed in wild-type and PKC-θ-deficient (PKC-θ-/-) mice. Here we report that PKC-θ is expressed in both human and mouse ILC2s. Mice lacking PKC-θ had reduced ILC2 numbers, TH2 cell numbers and activation, airway hyperresponsiveness, and expression of the transcription factors IRF4 and NFAT1. Importantly, adoptive transfer of ILC2s restored eosinophil influx and IL-4, IL-5 and IL-13 production in lung tissue, as well as TH2 cell activation. The pharmacologic PKC-θ inhibitor (Compound 20) administered during allergen challenge reduced ILC2 numbers and activation, as well as airway inflammation and IRF4 and NFAT1 expression. Therefore our findings identify PKC-θ as a critical factor for ILC2 activation that contributes to TH2 cell differentiation, which is associated with IRF4 and NFAT1 expression in allergic lung inflammation.

Overexpression of microRNA-155 suppresses chemokine expression induced by Interleukin-13 in BEAS-2B human bronchial epithelial cells

BackgroundMicroRNAs are non-coding small RNAs that regulate expression of target genes by binding to 3′ untranslated regions. In this study, we used bronchial epithelial cells to investigate in vitro the role of the microRNA miR-155 in the expression of chemokines associated with airway inflammation. miR-155 has previously been reported to regulate allergic inflammation. MethodsBEAS-2B bronchial epithelial cells were cultured and transfected with mimic or inhibitor oligonucleotides to overexpress or downregulate miR-155, as confirmed by real-time PCR. Cells were then stimulated with tumor necrosis factor-alpha, interleukin-13 (IL-13), and a double stranded RNA that binds Toll-like receptor 3. Expression and secretion of the chemokines CCL5, CCL11, CCL26, CXCL8, and CXCL10 were then quantified by real-time PCR and ELISA, respectively. Phosphorylation of signal transducer and activator of transcription 6 (STAT6), a target of the IL-13 receptor, was analyzed by ELISA.Results: miR-155 overexpression significantly suppressed IL-13-induced secretion of CCL11 and CCL26. These effects were specific, and were not observed for other chemokines, nor in cells with downregulated miR-155. miR-155 overexpression also suppressed CCL11 and CCL26 mRNA, but did not affect expression of the IL-13 receptor or phosphorylation of STAT6.Conclusions: miR-155 specifically inhibits IL-13-induced expression of eosinophilic chemokines CCL11 and CCL26 in bronchial epithelial cells, even though the 3'-untranslated region of these genes do not contain a consensus binding site for miR-155.

Elevated IL-33 expression is associated with pediatric eosinophilic esophagitis, and exogenous IL-33 promotes eosinophilic esophagitis development in mice.

We tested whether the T helper (Th) type 2 (Th2) cell agonist and allergenic ligand IL-33 was associated with eosinophilic esophagitis (EoE) development in a pediatric cohort and whether IL-33 protein could induce disease symptoms in mice. Biopsies from EoE patients or controls were used to measure IL-33 mRNA and protein expression. Increased expression of IL-33 mRNA was found in the esophageal mucosa in EoE. IL-33 protein was detected in cells negative for CD45, mast cells, and epithelial cell markers near blood vessels. Circulating levels of IL-33 were not increased. The time course for IL-33 gene expression was quantified in an established Aspergillus fumigatus allergen mouse model of EoE. Because IL-33 induction was transient in this model and chronicity of IL-33 expression has been demonstrated in humans, naive mice were treated with recombinant IL-33 for 1 wk and esophageal pathology was evaluated. IL-33 application produced changes consistent with phenotypically early EoE, including transmural eosinophilia, mucosal hyperproliferation, and upregulation of eosinophilic genes and chemokines. Th2 cytokines, including IL-13, along with innate lymphoid cell group 2, Th1/17, and M2 macrophage marker genes, were increased after IL-33 application. IL-33-induced eosinophilia was ablated in IL-13 null mice. In addition, IL-33 induced a profound inhibition of the regulatory T cell gene signature. We conclude that IL-33 gene expression is associated with pediatric EoE development and that application of recombinant protein in mice phenocopies the early clinical phase of the human disease in an IL-13-dependent manner. IL-33 inhibition of esophageal regulatory T cell function may induce loss of antigenic tolerance, thereby providing a mechanistic rationale for EoE development.

Eosinophil cytokines, chemokines, and growth factors: emerging roles in immunity.

Eosinophils derive from the bone marrow and circulate at low levels in the blood in healthy individuals. These granulated cells preferentially leave the circulation and marginate to tissues, where they are implicated in the regulation of innate and adaptive immunity. In diseases such as allergic inflammation, eosinophil numbers escalate markedly in the blood and tissues where inflammatory foci are located. Eosinophils possess a range of immunomodulatory factors that are released upon cell activation, including over 35 cytokines, growth factors, and chemokines. Unlike T and B cells, eosinophils can rapidly release cytokines within minutes in response to stimulation. While some cytokines are stored as pre-formed mediators in crystalloid granules and secretory vesicles, eosinophils are also capable of undergoing de novo synthesis and secretion of these immunological factors. Some of the molecular mechanisms that coordinate the final steps of cytokine secretion are hypothesized to involve binding of membrane fusion complexes comprised of soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNAREs). These intracellular receptors regulate the release of granules and vesicles containing a range of secreted proteins, among which are cytokines and chemokines. Emerging evidence from both human and animal model-based research has suggested an active participation of eosinophils in several physiological/pathological processes such as immunomodulation and tissue remodeling. The observed eosinophil effector functions in health and disease implicate eosinophil cytokine secretion as a fundamental immunoregulatory process. The focus of this review is to describe the cytokines, growth factors, and chemokines that are elaborated by eosinophils, and to illustrate some of the intracellular events leading to the release of eosinophil-derived cytokines.

Structural Basis of Receptor Sulfotyrosine Recognition by a CC Chemokine: The N-Terminal Region of CCR3 Bound to CCL11/Eotaxin-1

Trafficking of leukocytes in immune surveillance and inflammatory responses is activated by chemokines engaging their receptors. Sulfation of tyrosine residues in peptides derived from the eosinophil chemokine receptor CCR3 dramatically enhances binding to cognate chemokines. We report the structural basis of this recognition and affinity enhancement. We describe the structure of a CC chemokine (CCL11/eotaxin-1) bound to a fragment of a chemokine receptor: residues 8–23 of CCR3, including two sulfotyrosine residues. We also show that intact CCR3 is sulfated and sulfation enhances receptor activity. The CCR3 sulfotyrosine residues form hydrophobic, salt bridge and cation-p interactions with residues that are highly conserved in CC chemokines. However, the orientation of the chemokine relative to the receptor N terminus differs substantially from those observed for two CXC chemokines, suggesting that initial binding of the receptor sulfotyrosine residues guides subsequent steps in receptor activation, thereby influencing the receptor conformational changes and signaling.

Eosinophilic esophagitis: a clinicopathological review.

Eosinophilic esophagitis (EoE) is considered to be a chronic antigen-driven disease whereby food and/or aeroallergens induce a chronic inflammatory infiltrate in the esophagus, resulting in pathological hyperplasia of the epithelia and muscular layers, and fibrosis of the lamina propria (referred to collectively as remodelling) and the symptoms of dysphagia and food impaction. EoE shares features with other atopic conditions of asthma and atopic dermatitis, such as a TH2 cytokine milieu and a mixed inflammatory infiltrate of eosinophils, mast cells and lymphocytes. Relatively distinct features include the strong male predominance amongst adult patients, and the expression of the eosinophil chemokine eotaxin 3. Current first line treatments such as strict dietary modification and corticosteroids fail many patients. Looking forward, clarification of distinct genotype/phenotype associations, determining the reversibility of remodelling following treatment, and the development of new pharmacotherapies that target fibrotic pathways (as opposed to eosinophilic inflammation per se) or specifically improve barrier integrity appear relevant.