Eosinophil Chemotaxis Research Articles

Immunophenotyping of Acute Inflammatory Exacerbations of Lung Injury Driven by Mutant Surfactant Protein-C: A Role for Inflammatory Eosinophils.

Acute inflammatory exacerbations (AIEs) represent immune-driven deteriorations of many chronic lung conditions, including COPD, asthma, and pulmonary fibrosis (PF). The first line of therapy is represented by broad-spectrum immunomodulation. Among the several inflammatory populations mobilizing during AIEs, eosinophils have been identified as promising indicators of an active inflammatory exacerbation. To better study the eosinophil-parenchymal crosstalk during AIE-PF, this work leverages a clinically relevant model of inflammatory exacerbations triggered by inducible expression of a mutation in the alveolar epithelial type 2 cell Surfactant Protein-C gene [SP-CI73T]. Unbiased single-cell sequencing analysis of controls and SP-CI73T mutants at a time coordinated with peak eosinophilia (14 days) defined heightened inflammatory activation, chemotaxis, and survival signaling (IL-6, IL-4/13, STAT3, Glucocorticoid Receptor, mTOR, and MYC) in eosinophils. To study the impact of eosinophils in inflammatory exacerbations, the SP-CI73T line was crossed with eosinophil lineage deficient mice (GATA1Δdbl) to produce the SP-CI73TGATA1KO line. Time course analysis (7–42 days) demonstrated improved lung histology, survival, and reduced inflammation in SP-CI73TGATA1KO cohorts. Spectral flow cytometry of tissue digests confirmed eosinophil depletion in GATA1KO mice and the absence of a compensatory shift in neutrophils and immature monocyte recruitment. Eosinophil deletion resulted in progressive monocyte-derived macrophage accumulation (14 days post-injury), combined with declines in CD3+CD4+ lymphocyte and B220+ B cell abundance. Histochemical analysis revealed atypical inflammatory cell activation in SP-CI73TGATA1KO mice, with reduced numbers of Arg-1+ and iNOS+ cells, but increases in tgfb1 mRNA expression in bronchoalveolar lavage cells and tissue. Dexamethasone treatment (1 mg/kg daily, i.p.) was utilized to investigate corticosteroid efficacy in highly eosinophilic exacerbations induced by mutant SP-CI73T. Dexamethasone successfully reduced total and eosinophil (CD11b+SigF+CD11c−) counts at 14 days and was linked to reduced evidence of structural damage and perivascular infiltrate. Together, these results illustrate the deleterious role of eosinophils in inflammatory events preceding lung fibrosis and demonstrate the efficacy of corticosteroid treatment in highly eosinophilic exacerbations induced by mutant SP-CI73T.

Inflammatory Endotype-Associated Airway Resistome in Chronic Obstructive Pulmonary Disease.

ABSTRACTAntimicrobial resistance is a global concern in chronic respiratory diseases, including chronic obstructive pulmonary disease (COPD). The collection of antibiotic resistance genes or resistome in human airways may underlie the resistance. COPD is heterogeneous, and understanding the airway resistome in relation to patient phenotype and endotype may inform precision antibiotic therapy. Here, we characterized the airway resistome for 94 COPD participants at stable disease. Among all demographic and clinical factors, patient inflammatory endotype was associated with the airway resistome. There were distinct resistome profiles between patients with neutrophilic or eosinophilic inflammation, two primary inflammatory endotypes in COPD. For neutrophil-predominant COPD, the resistome was dominated by multidrug resistance genes. For eosinophil-predominant COPD, the resistome was diverse, with an increased portion of patients showing a macrolide-high resistome. The differential antimicrobial resistance pattern was validated by sputum culture and in vitro antimicrobial susceptibility testing. Ralstonia and Pseudomonas were the top contributors to the neutrophil-associated resistome, whereas Campylobacter and Aggregatibacter contributed most to the eosinophil-associated resistome. Multiomic analyses revealed specific host pathways and inflammatory mediators associated with the resistome. The arachidonic acid metabolic pathway and matrix metallopeptidase 8 (MMP-8) exhibited the strongest associations with the neutrophil-associated resistome, whereas the eosinophil chemotaxis pathway and interleukin-13 (IL-13) showed the greatest associations with the eosinophil-associated resistome. These results highlight a previously unrecognized link between inflammation and the airway resistome and suggest the need for considering patient inflammatory subtype in decision-making about antibiotic use in COPD and broader chronic respiratory diseases.IMPORTANCE Antibiotics are commonly prescribed for both acute and long-term prophylactic treatment in chronic airway disorders, such as chronic obstructive pulmonary disease (COPD), and the rapid growth of antibiotic resistance is alarming globally. The airway harbors a diverse collection of microorganisms known as microbiota, which serve as a reservoir for antibiotic resistance genes or the resistome. A comprehensive understanding of the airway resistome in relation to patient clinical and biological factors may help inform decisions to select appropriate antibiotics for clinical therapies. By deep multiomic profiling and in vitro phenotypic testing, we showed that inflammatory endotype, the underlying pattern of airway inflammation, was most strongly associated with the airway resistome in COPD patients. There were distinct resistome profiles between neutrophil-predominant and eosinophil-predominant COPD that were associated with different bacterial species, host pathways, and inflammatory markers, highlighting the need of considering patient inflammatory status in COPD antibiotic management.

Effect of IL-35 on apoptosis, adhesion, migration, and activation of eosinophils in allergic rhinitis.

Eosinophils play critical roles in the development of allergic rhinitis (AR) by releasing toxic substance. Interleukin-35 (IL-35), a newly identified anti-inflammatory cytokine, had potent inhibitive role for eosinophil infiltration in allergic disease. However, the direct effect of IL-35 on eosinophil was not clear. Twenty AR children and sixteen controls were recruited. The correlation between IL-35 protein expression and blood eosinophil counts and activation was analyzed. The effect of IL-35 on eosinophil apoptosis and adhesion was analyzed by flow cytometry. Transwell system was used for the migration assay. The eosinophil cationicprotein (ECP) from supernatant of eosinophils after IL-35stimulation was detected by enzyme-linked immunosorbent assay kits. The IL-35 protein levels were negatively correlated with eosinophil counts (p<.01) and ECP concentration (p<.01) in AR children. IL-35 promotes apoptosis and inhibits adhesion, migration, and activation of eosinophils. Moreover, the mRNA expression of IL-12 receptor β2 and glycoprotein 130 were significantly enhanced by eosinophils after IL-35stimulation. The apoptosis induced by IL-35 was mediated by phosphoinositide 3-kinase (PI3K) pathway. IL-35 inhibits adhesion of eosinophils through extracellular regulated proteinkinases (ERK) and PI3K pathways. The eosinophil chemotaxis and activation affected by IL-35 were mediated by PI3K and p38mitogen-activated proteinkinase (MAPK) pathways. Our results confirmed that IL-35 played inhibitive roles in apoptosis, adhesion, migration, and activation of eosinophils in AR, implying that IL-35may be used as treatment target in future.

Role of CCR3 in respiratory syncytial virus infection of airway epithelial cells

SummaryRespiratory syncytial virus (RSV) infection is the principal cause of severe lower respiratory tract disease and accounts for a significant risk for developing asthma later in life. Clinical studies have shown an increase in airway responsiveness and a concomitant Th2 response in the lungs of RSV-infected patients. These indications suggest that RSV may modulate aspects of the immune response to promote virus replication. Here, we show that CCR3 facilitates RSV infection of airway epithelial cells, an effect that was inhibited by eotaxin-1/CCL11 or upon CCR3 gene silencing. Mechanistically, cellular entry of RSV is mediated by binding of the viral G protein to CCR3 and selective chemotaxis of Th2 cells and eosinophils. In vivo, mice lacking CCR3 display a significant reduction in RSV infection, airway inflammation, and mucus production. Overall, RSV G protein-CCR3 interaction may participate in pulmonary infection and inflammation by enhancing eosinophils' recruitment and less potent antiviral Th2 cells.

The JAK1/2 inhibitor baricitinib suppresses eosinophil effector function and restricts allergen-induced airway eosinophilia

BackgroundEosinophilic asthma is increasingly recognized as one of the most severe and difficult-to-treat asthma subtypes. The JAK/STAT pathway is the principal signaling mechanism for a variety of cytokines and growth factors involved in asthma. However, the direct effect of JAK inhibitors on eosinophil effector function has not been addressed thus far. ObjectiveHere we compared the effects of the JAK1/2 inhibitor baricitinib and the JAK3 inhibitor tofacitinib on eosinophil effector function in vitro and in vivo. MethodsDifferentiation of murine bone marrow-derived eosinophils. Migratory responsiveness, respiratory burst, phagocytosis and apoptosis of human peripheral blood eosinophils were assessed in vitro. In vivo effects were investigated in a mouse model of acute house dust mite-induced airway inflammation in BALB/c mice. ResultsBaricitinib more potently induced apoptosis and inhibited eosinophil chemotaxis and respiratory burst, while baricitinib and tofacitinib similarly affected eosinophil differentiation and phagocytosis. Of the JAK inhibitors, oral application of baricitinib more potently prevented lung eosinophilia in mice following allergen challenge. However, both JAK inhibitors neither affected airway resistance nor compliance. ConclusionOur data suggest that the JAK1/2 inhibitor baricitinib is even more potent than the JAK3 inhibitor tofacitinib in suppressing eosinophil effector function. Thus, targeting the JAK1/2 pathway represents a promising therapeutic strategy for eosinophilic inflammation as observed in severe eosinophilic asthma.

Ameliorative effects of eosinophil deficiency on immune response, endoplasmic reticulum stress, apoptosis, and autophagy in fungus-induced allergic lung inflammation

BackgroundRespiratory fungal exposure is known to be associated with various allergic pulmonary disorders. Eosinophils have been implicated in tissue homeostasis of allergic inflammation as both destructive effector cells and immune regulators. What contributions eosinophils have in Aspergillus fumigatus (Af)-induced allergic lung inflammation is worthy of investigating.MethodsWe established the Af-exposed animal asthmatic model using eosinophil-deficient mice, ∆dblGATA1 mice. Airway inflammation was assessed by histopathological examination and total cell count of bronchoalveolar lavage fluid (BALF). The protein level in BALF and lung mRNA level of type 2 cytokines IL-4, IL-5, and IL-13 were detected by ELISA and qRT-PCR. We further studied the involvement of endoplasmic reticulum (ER) stress, apoptosis, and autophagy by western blots, qRT-PCR, immunofluorescence, TUNEL, or immunohistochemistry. RNA-Seq analysis was utilized to analyze the whole transcriptome of Af-exposed ∆dblGATA1 mice.ResultsHematoxylin and eosin (HE) staining and periodic acid–Schiff staining (PAS) showed that airway inflammation and mucus production were alleviated in Af-challenged ∆dblGATA1 mice compared with wild-type controls. The protein and mRNA expressions of IL-4, IL-5, and IL-13 were reduced in the BALF and lung tissues in Af-exposed ∆dblGATA1 mice. The results demonstrated that the significantly increased ER stress markers (GRP78 and CHOP) and apoptosis executioner caspase proteases (cleaved caspase-3 and cleaved caspase-7) in Af-exposed wild-type mice were all downregulated remarkably in the lungs of ∆dblGATA1 mice with Af challenge. In addition, the lung autophagy in Af-exposed ∆dblGATA1 mice was found elevated partially, manifesting as higher expression of LC3-II/LC3-I and beclin1, lower p62, and downregulated Akt/mTOR pathway compared with Af-exposed wild-type mice. Additionally, lung RNA-seq analysis of Af-exposed ∆dblGATA1 mice showed that biological processes about chemotaxis of lymphocytes, neutrophils, or eosinophils were enriched but without statistical significance.ConclusionsIn summary, eosinophils play an essential role in the pathogenesis of Af-exposed allergic lung inflammation, whose deficiency may have relation to the attenuation of type 2 immune response, alleviation of ER stress and apoptosis, and increase of autophagy. These findings suggest that anti-eosinophils therapy may provide a promising direction for fungal-induced allergic pulmonary diseases.

Analysis of Mouse Eosinophil Migration and Killing of Tumor Cells.

Eosinophils are bone marrow-derived cells that differentiate in the bone marrow and migrate into the peripheral blood primarily under the regulation of interleukin (IL)-5. Despite the fact that eosinophils have been mostly studied in the context of allergic inflammatory diseases, eosinophils accumulate in multiple tumors. In fact, recent data highlight key anti-tumorigenic activities for eosinophils. Thus, developing simple assays that will dissect the interactions between eosinophils and tumor cells is important since these assays will provide tools to study eosinophils in the tumor microenvironment. In this chapter, we provide detailed methods for isolating eosinophils from Il5 transgenic mice. Furthermore, we provide methodology to assess eosinophil chemotaxis in response to tumor-secreted factors. Finally, we describe a co-culture system of eosinophils and tumor cells aimed to determine the cytotoxic capabilities of eosinophils.

Diminished Expression of Galectin-3 Around Blisters in Bullous Pemphigoid: An Immunohistochemistry Study.

BackgroundBullous pemphigoid (BP) is a subepidermal blistering disorder caused by autoantibodies directed against hemidesmosomal proteins. Many patients with BP demonstrate circulating IgE autoantibodies. Although the role of IgE in the pathogenesis of BP is unknown, a correlation between IgE antibodies and eosinophilia has been observed. Soluble CD23 and galectin-3 are the main elements of the IgE group. The roles for CD23 in BP as a potential biomarker and IgE production regulator have been characterized, but no studies have evaluated any roles for galectin-3 in this disease.ObjectiveIn this study, we evaluated galectin-3 expression in BP as a first step in assessing its role in the pathogenesis of this autoimmune blistering process.Patients and MethodsSixty specimens diagnosed as BP were stained with antibodies to galectin-3. The percentages of nuclear and cytoplasmic galectin-3 expression and staining intensity were evaluated.ResultsThere was a significant difference in galectin-3 cytoplasmic and nuclear expression within keratinocytes immediately surrounding and above the blisters: (1) cytoplasmic (mean = 17.2% ± 2.4%) vs adjacent unaffected skin (mean = 66.7% ± 2.0%, P < 0.0001) and (2) nuclear (mean = 1.9% ± 0.4%) vs adjacent unaffected skin (mean = 13.2% ± 1.2%, P < 0.0001).ConclusionsLower expression of galectin-3 around blisters in BP may suggest a role as an adhesion molecule. Loss of galectin-3 may add to the extension of blister formation by initiating cell-extracellular matrix disassembly and may be involved with the associated dermal inflammation and the eosinophil chemotaxis. Further studies will be necessary to elucidate the result of this observed loss on disease pathogenesis.

Onion Bulb Extract Downregulates EGFR/ERK1/2/AKT Signaling Pathway and Synergizes With Steroids to Inhibit Allergic Inflammation

The treatment of allergic diseases, such as asthma, with both conventional and novel therapies presents a challenge both in terms of optimal effect and cost. On the other hand, traditional therapies utilizing natural products such as onion have been in use for centuries with demonstrated efficacy and safety but without much knowledge of their mechanims of action. In this study, we investigated if the anti-inflammatory effects of onion bulb extract (OBE) are mediated via the modulation of the EGFR/ERK1/2/AKT signaling pathway, and whether OBE can synergise with steroids to produce greater anti-inflammatory actions. Treatment with OBE inhibited the house dust mite (HDM)-induced increased phosphorylation of EGFR, ERK1/2 and AKT which resulted in the inhibition of HDM-induced increase in airway cellular influx, perivascular and peribronchial inflammation, goblet cell hyper/metaplasia, and also inhibited ex vivo eosinophil chemotaxis. Moreover, treatment with a combination of a low dose OBE and low dose dexamethasone resulted in a significant inhibition of the HDM-induced cellular influx, perivascular and peribronchial inflammation, goblet cell hyper/metaplasia, and increased the pERK1/2 levels, whereas neither treatment, when given alone, had any discernible effects. This study therefore shows that inhibition of the EGFR/ERK1/2/AKT-dependent signaling pathway is one of the key mechanisms by which OBE can mediate its anti-inflammatory effects in diseases such as asthma. Importantly, this study also demonstrates that combining OBE with steroids results in significantly enhanced anti-inflammatory effects. This action may have important potential implications for future asthma therapy.

STEROID DEPENDENT CHRONIC EOSINOPHILIC PNEUMONIA: A WIN FOR IL-5 ANTAGNONISM IN AN ACTIVE DUTY SERVICE MEMBER

SESSION TITLE: Fellows Diffuse Lung Disease Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: October 18-21, 2020 INTRODUCTION: Chronic eosinophilic pneumonia (CEP) is characterized by a clinical syndrome which includes pulmonary symptoms, eosinophilia greater than 25% in bronchoalveolar lavage, and characteristic radiographic abnormalities. Corticosteroids are the mainstay of therapy. There is no standard alternative for steroid-refractory/dependent CEP, however, reports suggest anti-IL5 therapies may be an option. We present the case of a non-asthmatic, active duty service member with steroid dependent CEP who had a dramatic clinical response to mepolizumab. CASE PRESENTATION: A 47-year-old African American female presented to us for persistent productive cough and dyspnea despite multiple rounds of steroids and antibiotics for “recurrent upper respiratory infections”. Our evaluation was notable for thoracic lymphadenopathy and diffuse ground glass opacities on CT, a positive environmental allergy screen, IgE of > 4,000 IU/mL and an absolute serum eosinophil count of over 3,400. Pulmonary function testing, to include bronchoprovocation testing was normal. A diagnosis of allergic bronchopulmonary aspergillosis (ABPA) was excluded due to negative precipitins panel and lack of classic radiographic findings. Bronchoscopic evaluation revealed tissue eosinophilia with eosinophilic granuloma formation and no evidence of vasculitis. BAL from two separate lobes revealed a cell differential > 25% eosinophils with all infectious testing negative. An ANCA panel was positive for PR3, however, subsequent work up to include numerous biopsies of various sites, was not consistent with Eosinophilic Granulomatosis with Polyangitis (EGPA), especially in this non-asthmatic. We started steroid therapy for CEP which resulted in clinical improvement, however, our patient could not be weaned below 20mg daily without resulting in symptom relapse. For her steroid-dependent CEP we trialed mepolizumab, resolving her symptoms and radiographic findings, allowing cessation of all steroids DISCUSSION: IL-5 antagnosts, like mepolizumab, bind and neutralize IL-5 thereby inhibiting eosinophil production, activation and chemotaxis (1). They are used in eosinophilic asthma to relieve airway inflammation. In CEP, eosinophils also drive chronic inflammation. Steroids are classically considered the cornerstone of therapy for these patients and can generally be weaned, however, in this case the patient had steroid dependent disease necessitating consideration for alternative therapies. In the literature, anti-IL-5 therapy is non-asthmatics is discussed, however, to the best of our knowledge, there is only one published case documenting successful use of mepolizumab in CEP (2). CONCLUSIONS: Mepolizumab appears to be a promising therapy for patients with CEP and may be considered in patients who do not respond to, or are dependent on, steroids. More research must be done into such non-steroidal agents to reduce exposure to steroids and their side effects. Reference #1: 1. Garrett JK, Jameson SC, Thomson B, et al. Anti-interleukin-5 (mepolizumab) therapy for hypereosinophilic syndromes. J Allergy Clin Immunol. 2004;113(1):115-9. Reference #2: 2 To M, Kono Y, Yamawaki S, et al. A case of chronic eosinophilic pneumonia successfully treated with mepolizumab. J Allergy Clin Immunol Pract. 2018;6(5):1746-1748.e1. DISCLOSURES: No relevant relationships by Cyrus Askin, source=Web Response No relevant relationships by Tyson Sjulin, source=Web Response

MicroRNA miR-155-5p knockdown attenuates Angiostrongylus cantonensis-induced eosinophilic meningitis by downregulating MMP9 and TSLP proteins

Angiostrongylus cantonensis infection is a major cause of eosinophilic meningitis (EM). Severe cases or cases that involve infants and children present poor prognoses. MicroRNAs (miRNAs), which are important regulators of gene expression in many biological processes, were recently found to be regulators of the host response to infection by parasites; however, their roles in brain inflammation caused by A. cantonensis are still unclear. The current study confirmed that miR-155-5p peaked at 21 days after A. cantonensis infection, and its expression was positively correlated with the concentration of excretory and secretory products (ESPs). We found that miR-155-5p knockdown lentivirus successfully ameliorated brain injury and downregulated the expression of major basic protein (MBP) in vivo, and the number of eosinophils in CSF (and the percentage of eosinophils in peripheral blood were also decreased in the miR-155-5p knockdown group. Moreover, the expression of several eosinophilic inflammation cytokines such as CCL6/C10, ICAM-1, and MMP9, declined after the miR-155-5p knockdown. SOCS1 protein, which is an important negative regulator of inflammation activation, was identified as a direct miR-155-5p target. We further detected the effect of miR-155-5p knockdown on phosphorylated-STAT3 and phosphorylated-p65 proteins, which were found to be negatively regulated by SOCS1 and play an important role in regulating the inflammatory response. We found that miR-155-5p knockdown decreased the activity of p-STAT3 and p-p65, thereby leading to lower expression of MMP9 and TSLP proteins, which were closely related to the chemotaxis and infiltration of eosinophils. Interestingly, the inhibition of p-STAT3 or p-p65 was found to induce the downregulation of miR-155-5p in an opposite manner. These observations suggest that a positive feedback loop was formed between miR-155-5p, STAT3, and NF-κB in A. cantonensis infection and that miR-155-5p inhibition might provide a novel strategy to attenuate eosinophilic meningitis.

Eotaxins and Their Receptor in Colorectal Cancer-A Literature Review.

Colorectal cancer (CRC) is one of the most common malignancies in the world, with a global incidence of almost 2 million new cases every year. Despite the availability of many diagnostic tests, including laboratory tests and molecular diagnostics, an increasing number of new cases is observed. Thus, it is very important to search new markers that would show high diagnostic sensitivity and specificity in the detection of colorectal cancer in early stages of the disease. Eotaxins are proteins that belong to the cytokine group—small molecules with a variety of applications. Their main role is the activation of basophils and eosinophils involved in inflammatory processes. Therefore, we performed an extensive search of the literature pertaining to our investigation via the MEDLINE/PubMed database. On the basis of available literature, we can assume that eotaxins accumulate in cancer cells in the course of CRC. This leads to a decrease in the chemotaxis of eosinophils, which are effector immune cells with anti-tumor activity. This may explain a decrease in their number as a defense mechanism of cancer cells against their destruction and may be useful when attempting anti-tumor therapy with the use of chemokines.

Enigmatic Histamine Receptor H4 for Potential Treatment of Multiple Inflammatory, Autoimmune, and Related Diseases.

The histamine H4 receptor, belonging to the family of G-protein coupled receptors, is an increasingly attractive drug target. It plays an indispensable role in many cellular pathways, and numerous H4R ligands are being studied for the treatment of several inflammatory, allergic, and autoimmune disorders, including pulmonary fibrosis. Activation of H4R is involved in cytokine production and mediates mast cell activation and eosinophil chemotaxis. The importance of this receptor has also been shown in inflammatory models: peritonitis, respiratory tract inflammation, colitis, osteoarthritis, and rheumatoid arthritis. Recent studies suggest that H4R acts as a modulator in cancer, neuropathic pain, vestibular disorders, and type-2 diabetes, however, its role is still not fully understood.

Ang-(1-7)/ MAS1 receptor axis inhibits allergic airway inflammation via blockade of Src-mediated EGFR transactivation in a murine model of asthma.

The angiotensin-(1–7) [Ang-(1–7)]/MAS1 receptor signaling axis is a key endogenous anti-inflammatory signaling pathway. However, the mechanisms by which its mediates the anti-inflammatory effects are not completely understood. Using an allergic murine model of asthma, we investigated whether Ang-1(1–7)/MAS1 receptor axis a): inhibits allergic inflammation via modulation of Src-dependent transactivation of the epidermal growth factor receptor (EGFR) and downstream signaling effectors such as ERK1/2, and b): directly inhibits neutrophil and/or eosinophil chemotaxis ex vivo. Ovalbumin (OVA)-induced allergic inflammation resulted in increased phosphorylation of Src kinase, EGFR, and ERK1/2. In addition, OVA challenge increased airway cellular influx, perivascular and peribronchial inflammation, fibrosis, goblet cell hyper/metaplasia and airway hyperresponsiveness (AHR). Treatment with Ang-(1–7) inhibited phosphorylation of Src kinase, EGFR, ERK1/2, the cellular and histopathological changes and AHR. Ang-(1–7) treatment also inhibited neutrophil and eosinophil chemotaxis ex vivo. These changes were reversed following pre-treatment with A779. These data show that the anti-inflammatory actions of Ang-(1–7)/ MAS1 receptor axis are mediated, at least in part, via inhibition of Src-dependent transactivation of EGFR and downstream signaling molecules such as ERK1/2. This study therefore shows that inhibition of the Src/EGRF/ERK1/2 dependent signaling pathway is one of the mechanisms by which the Ang-(1–7)/ MAS1 receptor axis mediates it anti-inflammatory effects in diseases such as asthma.

Epidermal expression of eotaxins and thymic stromal lymphopoietin in eosinophil rich dermatoses.

Eosinophils are seen in a number of dermatologic conditions. While the extent of their function in these diseases remains to be fully elucidated, pathogenic activity in bullous pemphigoid suggests a more significant role than previously thought. Several dermatoses have a fairly characteristic histologic morphology of eosinophil infiltration. We hypothesized that epidermal expression of eotaxins and TSLP would differ by disease, perhaps explaining the different histologic morphologies. We performed a retrospective study of eosinophil rich dermatoses to perform immunohistochemistry. We collected 49 specimens composed of bullous pemphigoid (n = 15), atopic dermatitis (n = 12), drug rash (n = 8), arthropod assault (n = 5), and non-bullous pemphigoid eosinophilic spongiosis (n = 5). We used lichen planus (n = 4) as a control for lymphocyte-mediated inflammation. TSLP was diffusely expressed in all epidermal samples, whereas eotaxins demonstrated a weaker staining. Eotaxins and TSLP demonstrated a gradientbetween basal and spinous keratinocytes. The correlation between overall basal keratinocyte and spinous keratinocyte staining of eotaxins and TSLP with the number of eosinophils demonstrated a significant correlation between eotaxin-1 (R = 0.404, P = 0.004), eotaxin-2 (R = 0.576, P < 0.001), and eotaxin-3 (R = 0.512, P < 0.001), but not TSLP (R = 0.164, P = 0.251). These remained significant after correcting for multiple comparisons. While we were unable to detect significant differences in epidermal expression of eotaxins and TSLP in various eosinophil rich dermatoses, we identified a significant correlation of spinous keratinocyte eotaxin staining with tissue eosinophilia. Our identification of a correlation of spinous keratinocyte eotaxin staining with tissue eosinophilia may provide insight into local eosinophil chemotaxis.

H1-Antihistamines for Allergic Diseases: Old Aged but Not Old-Fashioned Drugs

Histamine is a chemical messenger synthesized from the amino acid histidine by L-histidine decarboxylase. It plays an important role in the system of immunoregulation and in acute and chronic allergic inflammation binding to four subtypes of receptors H1, H2, H3 and H4, described as heptahelical transmembrane molecules that activate specific G-proteins. These receptors placed on the membranes of different cellular jambs (mast cells, endothelial cells, sensory nerve fibres, bronchial smooth muscle) cause different biological actions: Vasodilatation, increased vascular permeability, itching, smooth muscle contraction, coronary spasm, sleep-wake rhythm regulation. Histamine interaction with H1-receptors potentially leads to increasing antigen-presenting cell capacity, release of histamine and other mediators from mast cells and basophils inducing cellular adhesion molecule expression and chemotaxis of eosinophils and neutrophils.

Hesperidin treatment inhibits chemokine secretion and eosinophil chemotaxis in airway epithelium

Hesperidin treatment inhibits chemokine secretion and eosinophil chemotaxis in airway epithelium

Glucose metabolism dictates murine eosinophil differentiation, chemotaxis, and IL-4 expression

Glucose metabolism dictates murine eosinophil differentiation, chemotaxis, and IL-4 expression

Novel peptide nanoparticle–biased antagonist of CCR3 blocks eosinophil recruitment and airway hyperresponsiveness

Chemokine signaling through CCR3 is a key regulatory pathway for eosinophil recruitment into tissues associated with allergic inflammation and asthma. To date, none of the CCR3 antagonists have shown efficacy in clinical trials. One reason might be their unbiased mode of inhibition that prevents receptor internalization, leading to drug tolerance. We sought to develop a novel peptide nanoparticle CCR3 inhibitor (R321) with a biased mode of inhibition that would block G protein signaling but enable or promote receptor internalization. Self-assembly of R321 peptide into nanoparticles and peptide binding to CCR3 were analyzed by means of dynamic light scattering and nuclear magnetic resonance. Inhibitory activity on CCR3 signaling was assessed invitro by using flow cytometry, confocal microscopy, and Western blot analysis in a CCR3+ eosinophil cell line and blood eosinophils. Invivo effects of R321 were assessed by using a triple-allergen mouse asthma model. R321 self-assembles into nanoparticles and binds directly to CCR3, altering receptor function. Half-maximal inhibitory concentration values for eotaxin-induced chemotaxis of blood eosinophils are in the low nanomolar range. R321 inhibits only the early phase of extracellular signal-regulated kinase 1/2 activation and not the late phase generally associated with β-arrestin recruitment and receptor endocytosis, promoting CCR3 internalization and degradation. Invivo R321 effectively blocks eosinophil recruitment into the blood, lungs, and airways and prevents airway hyperresponsiveness in a mouse eosinophilic asthma model. R321 is a potent and selective antagonist of the CCR3 signaling cascade. Inhibition through a biased mode of antagonism might hold significant therapeutic promise by eluding the formation of drug tolerance.

Biological Therapies for Eosinophilic Esophagitis: Where Do We Stand?

Eosinophilic esophagitis (EoE) is an immune-mediated, chronic esophageal disease characterized by esophageal symptoms and esophageal eosinophilia. It is triggered by foods and possibly by environmental allergens. Currently, there are no FDA-approved therapies for EoE. Commonly used treatments include dietary restrictions and topical corticosteroids. Many of these therapies are suboptimal in their efficacy, have side effects, or diminish patients' quality of life. Biologic therapies for EoE have therefore been sought as an alternative. The mechanism by which food allergens trigger EoE is thought to be a T helper type 2 (Th2) reaction, resulting in secretion of the cytokines IL-4, IL-5, and IL-13. IL-5 induces eosinophil production and trafficking to the esophagus, and IL-13 induces esophageal epithelial cells to secrete eotaxin-3, which drives eosinophil chemotaxis and activation. Mepolizumab and reslizumab, two anti-IL-5 antibodies, were studied in children and adults with EoE and resulted in reduction of esophageal tissue and blood eosinophils, but no significant reduction in symptoms. QAX576, an anti-IL-13 antibody, was studied in adults with EoE and showed a decrease in the esophageal eosinophil load and a trend towards clinical improvement. Since in situ IgE production was demonstrated in the EoE esophagus, omalizumab, an anti-IgE antibody, was studied in patients with EoE and not found to be overall beneficial. Furthermore, given the increased esophageal epithelial cell TNF-α expression in EoE, infliximab, an anti-TNF-α antibody, was studied in patients with EoE, with lack of success both clinically and histologically. In summary, although none of the biologicals studied so far in EoE have been highly effective, many demonstrated some histological benefit, especially those that targeted the Th2 axis. Therefore, the future for biologicals is promising as the pathophysiology of EoE is better understood, clinical assessment tools are validated, identification of patient subsets that respond best to biologicals is made, and dosages of biologicals are optimized.