Bronchiolitis and recurrent wheezing are distinguished by type 2 innate lymphoid cells and immune response.

BACKGROUND: Recurrent wheezing (RW) is frequently developed in infants that have suffered bronchiolitis (BCH) during first months of life, but the immune mechanism underlying is not clear. The goal was to analyze the innate immune response that characterizes BCH and RW. METHODS: Ninety-eight and seventy hospitalized infants with BCH or RW diagnosis, respectively, were included. Nasopharyngeal aspirate (NPA) was processed. Cellular pellet was employed to evaluate type 2 innate lymphoid cells (ILC2) by flow cytometry and mRNA expression assays by semi-quantitative real-time PCR (qRT-PCR). In supernatant, twenty-seven pro-inflammatory and immunomodulatory factors, as well as lipid mediators and nitrites, were evaluated by ELISA and Luminex. RESULTS: Bronchiolitis patients showed higher ILC2 percentage compared with RW (P < .05). Also, ST2+ /ILC2 percentage was higher in the BCH group than in the RW group (P < .01). TLR3, IL33, IFNG, IL10, and FLG mRNA levels were significantly increased in BCH vs RW (P < .05). In supernatant, no significant differences were reached, observing similar levels of parameters linked to vascular damage, monocyte activation, and fibroblast growth. Prostaglandin E2 and cysteinyl leukotrienes C4 were evaluated; a significant difference was only found in their ratio. CONCLUSION: Bronchiolitis is associated with elevated nasal percentage of ILC2. This cellular population could be the key element in the differential immune response between BCH and RW which share some mechanisms such us monocyte activation, vascular damage, and fibroblast repair. Lipid mediators could play a role in the evolution of the disease later in life through innate lymphoid cells.

Immune recovery following bronchiolitis is linked to a drop in cytokine and LTC4 levels.

BACKGROUND: Bronchiolitis is the main cause of hospitalization of children younger than 1 year; however, the immune mechanism of bronchiolitis is not completely understood. The aim of this study was to analyze the recovery of immune response after a bronchiolitis episode. METHODS: Forty-nine infants hospitalized with bronchiolitis diagnosis were enrolled. Nasopharyngeal aspirates (NPAs) were processed. Twenty-seven pro-inflammatory biomarkers linked to innate immunity, inflammation, and epithelial damage, as well as nitrites and lipid mediators, were evaluated in the NPA supernatant by ELISA (enzyme-linked immunosorbent assay) and Luminex. Also, 11 genes were analyzed in NPA cells by quantitative PCR. RESULTS: A widespread statistically significant decline of multiple pro-inflammatory parameters and cytokines were detected in the recovery period after respiratory infection: interferon-α2 (IFNα2), IFNγ, interleukin-10 (IL-10), IL-1ß, IL-8, IFN-γ-inducible protein-10, vascular endothelial growth factor, monocyte chemoattractant protein-1, macrophage inflammatory protein-1α (MIP-1α), and MIP-1ß. Supporting these results, a decreased nuclear factor-κB gene expression was observed (P = 0.0116). A significant diminution of cysteinyl leukotriene C4 (LTC4) soluble levels (P = 0.0319) and cyclooxygenase-2 (COX-2) gene expression were observed in the recovery sample. In children classified by post-bronchiolitis wheezing, LTC4 remains elevated in the NPA supernatant. CONCLUSIONS: After bronchiolitis, cytokines and biomarkers linked to innate immune response in NPA decrease significantly in the recovery period accompanied by a drop in LTC4 levels; however, this reduction was lower in infants with post-bronchiolitis wheezing.

Proton-pump Inhibitor Response Prediction Using Esophageal microRNAs in Children With Eosinophilic Esophagitis.

OBJECTIVES: Eosinophilic esophagitis (EoE) is a chronic esophageal disease characterized by eosinophilic inflammation. Proton-pump inhibitors (PPI) induce disease remission but no predictive factors of PPI-responsiveness have been identified yet. So, a biomarker must be found to differentiate between responders (PPI-R) and nonresponder patients (PPI-NR) to PPI. Aims were to identify any molecular biomarker that could predict PPI responsiveness and to study molecular remission after PPI therapy. METHODS: This prospective study enrolled 39 controls and 43 pediatric children with EoE from 2 hospitals, and they were treated with esomeprazole for 8 to 12 weeks. After therapy, patients were classified as either PPI-R or PPI-NR. Biopsies were collected and RNA, microRNAs, and proteins were isolated from them, measuring levels by qPCR and Western blot (WB). Also, miRNAs were evaluated in serum. RESULTS: We found several esophageal miRNAs with different expression values between PPI-R and PPI-NR children, which can be used to discriminate them (area under curve = 0.90). No useful serum miRNAs were, however, identified. Also, these miRNAs were dysregulated in responder patients before and after PPI therapy. Moreover, we corroborated in this child population, that PPI-R displayed a significant decrease in eotaxin-3, IL-5, IL-13, periostin, and major basic protein (P < 0.05) and a significant increase in filaggrin levels after PPI treatment (P < 0.01). CONCLUSIONS: Esophageal miRNA levels found are able to discriminate between both PPI-R and PPI-NR at baseline, and before and after treatment in PPI-R, so they could be used as biomarkers. Furthermore, we observed clinical and esophageal molecular restoration in PPI-R patients after PPI therapy.

Exosome secretion by eosinophils: A possible role in asthma pathogenesis.

BACKGROUND: Eosinophils secrete several granules that are involved in the propagation of inflammatory responses in patients with pathologies such as asthma. OBJECTIVE: We hypothesized that some of these granules are exosomes, which, when transferred to the recipient cells, could modulate asthma progression. METHODS: Eosinophils were purified from peripheral blood and cultured with or without IFN-γ or eotaxin. Multivesicular bodies (MVBs) in eosinophils were studied by using fluorescence microscopy, transmission electron microscopy (TEM), and flow cytometry. Exosome secretion was measured and exosome characterization was performed with TEM, Western blotting, and NanoSight analysis. RESULTS: Generation of MVBs in eosinophils was confirmed by using fluorescence microscopy and flow cytometry and corroborated by means of TEM. Having established that eosinophils contain MVBs, our aim was to demonstrate that eosinophils secrete exosomes. To do this, we purified exosomes from culture medium of eosinophils and characterized them. Using Western blot analysis, we demonstrated that eosinophils secreted exosomes and that the discharge of exosomes to extracellular media increases after IFN-γ stimulation. We measured exosome size and quantified exosome production from healthy and asthmatic subjects using nanotracking analysis. We found that exosome production was augmented in asthmatic patients. CONCLUSION: Our findings are the first to demonstrate that eosinophils contain functional MVBs and secrete exosomes and that their secretion is increased in asthmatic patients. Thus exosomes might play an important role in the progression of asthma and eventually be considered a biomarker.

Group 2 innate lymphoid cells are key in lipid transfer protein allergy pathogenesis.

Background: Immunopathology in food allergy is characterized by an uncontrolled type 2 immune response and specific-IgE production. Recent studies have determined that group 2 innate lymphoid cells (ILC2) participate in the food allergy pathogenic mechanism and their severity. Our objective was to investigate the role of ILC2 in peach-allergic patients due to non-specific lipid transfer protein (Pru p 3) sensitization. Methods: The immune response in peripheral blood mononuclear cells was characterized in lipid transfer protein-allergic patients and healthy controls. We have analyzed the Pru p 3 uptake on ILC2, the expression of costimulatory molecules, and their involvement on the T-cell proliferative response and cytokine production under different experimental conditions: cytokines involved in group 2 innate lymphoid cell activation (IL-33 and IL-25), Pru p 3 as main food allergen, and the combination of both components (IL-33/IL-25+Pru p 3) using cell sorting, EliSpot, flow cytometry, and confocal microscopy. Results: Our results show that Pru p 3 allergen is taken up by group 2 innate lymphoid cells, regulating their costimulatory molecule expression (CD83 and HLA-DR) depending on the presence of Pru p 3 and its combination with IL-33/IL-25. The Pru p 3-stimulated ILC2 induced specific GATA3+Th2 proliferation and cytokine (IL-4, IL-5, and IL-13) production in lipid transfer protein-allergic patients in a cell contact-dependent manner with no changes in Tbet+Th1- and FOXP3+Treg cell differentiation. Conclusions: The results indicate that in lipid transfer protein-allergic patients, the responsible allergen, Pru p 3, interacts with group 2 innate lymphoid cells, promoting a Th2 cell response. Our results might be of interest in vivo, as they show a role of group 2 innate lymphoid cells as antigen-presenting cells, contributing to the development of food allergy. Consequently, group 2 innate lymphoid cells may be considered as potential therapeutic targets.

Identification of Asthma Phenotypes in the Spanish MEGA Cohort Study Using Cluster Analysis.

INTRODUCTION: The definition of asthma phenotypes has not been fully established, neither there are cluster studies showing homogeneous results to solidly establish clear phenotypes. The purpose of this study was to develop a classification algorithm based on unsupervised cluster analysis, identifying clusters that represent clinically relevant asthma phenotypes that may share asthma-related outcomes. METHODS: We performed a multicentre prospective cohort study, including adult patients with asthma (N=512) from the MEGA study (Mechanisms underlying the Genesis and evolution of Asthma). A standardised clinical history was completed for each patient. Cluster analysis was performed using the kernel k-groups algorithm. RESULTS: Four clusters were identified. Cluster 1 (31.5% of subjects) includes adult-onset atopic patients with better lung function, lower BMI, good asthma control, low ICS dose, and few exacerbations. Cluster 2 (23.6%) is made of adolescent-onset atopic asthma patients with normal lung function, but low adherence to treatment (59% well-controlled) and smokers (48%). Cluster 3 (17.1%) includes adult-onset patients, mostly severe non-atopic, with overweight, the worse lung function and asthma control, and receiving combination of treatments. Cluster 4 (26.7%) consists of the elderly-onset patients, mostly female, atopic (64%), with high BMI and normal lung function, prevalence of smokers and comorbidities. CONCLUSION: We defined four phenotypes of asthma using unsupervised cluster analysis. These clusters are clinically relevant and differ from each other as regards FEV1, age of onset, age, BMI, atopy, asthma severity, exacerbations, control, social class, smoking and nasal polyps.

Methylation changes induced by a glycodendropeptide immunotherapy and associated to tolerance in mice.

Introduction: Allergen-specific immunotherapy (AIT) is applied as treatment to rise tolerance in patients with food allergies. Although AIT is thoroughly used, the underlying epigenetic events related to tolerant induction are still unknown. Thus, we aim to investigate epigenetic changes that could be related to tolerance in dendritic cells (DCs) from anaphylactic mice to lipid transfer proteins, Pru p 3, in the context of a sublingual immunotherapy (SLIT) with a glycodendropeptide (D1ManPrup3) that has demonstrated tolerant or desensitization responses depending on the treatment dose. Methods: Changes in DNA methylation in CpG context were determined comparing Sensitized (Antigen-only) animals and two groups receiving SLIT with the D1ManPrup3 nanostructure (D1ManPrup3-SLIT): Tolerant (2nM D1ManPrup3) and Desensitized (5nM D1ManPrup3), against anaphylactic animals. DNA from lymph nodes-DCs were isolated and then, Whole Genome Bisulphite Sequencing was performed to analyze methylation. Results: Most differentially methylated regions were found on the area of influence of gene promoters (DMPRs). Compared to the Anaphylactic group, the highest value was found in Desensitized mice (n = 7,713 DMPRs), followed by Tolerant (n = 4,091 DMPRs) and Sensitized (n = 3,931 DMPRs) mice. Moreover, many of these epigenetic changes were found in genes involved in immune and tolerance responses (Il1b, Il12b, Il1a, Ifng, and Tnf) as shown by functional enrichment (DCs regulation, B cell-mediated immunity, and effector mechanisms). Discussion: In conclusion, different doses of D1ManPrup3-SLIT induce different DNA methylation changes, which are reflected in the induction of distinct responses, tolerance, or desensitization.

Isolation and Functional Aspects of Eosinophil-Derived Exosomes.

Eosinophils are granulocytes involved in inflammatory processes related to type 2 immune responses as allergy and parasitic infestation. Eosinophils are scarce in homeostatic situations, comprising 3-6% of total granulocytes. In peripheral blood, they have a life span of 18-25 h. These cells are characterized by the presence of several types of granules that are very important because of their functions. Recently, we have described that these immune cells are able to release exosomes, which are nanovesicles involved in intercellular communication and implicated in development of several diseases such as cancer, cardiovascular diseases, and asthma. Here, we describe a technique for isolation of eosinophil-derived exosomes from human peripheral blood and for their utilization in cell functional assays.

Vitamin C activates pyruvate dehydrogenase (PDH) targeting the mitochondrial tricarboxylic acid (TCA) cycle in hypoxic KRAS mutant colon cancer.

Background: In hypoxic tumors, positive feedback between oncogenic KRAS and HIF-1α involves impressive metabolic changes correlating with drug resistance and poor prognosis in colorectal cancer. Up to date, designed KRAS-targeting molecules do not show clear benefits in patient overall survival (POS) so pharmacological modulation of aberrant tricarboxylic acid (TCA) cycle in hypoxic cancer has been proposed as a metabolic vulnerability of KRAS-driven tumors. Methods: Annexin V-FITC and cell viability assays were carried out in order to verify vitamin C citotoxicity in KRAS mutant SW480 and DLD1 as well as in Immortalized Human Colonic Epithelial Cells (HCEC). HIF1a expression and activity were determined by western blot and functional analysis assays. HIF1a direct targets GLUT1 and PDK1 expression was checked using western blot and qRT-PCR. Inmunohistochemical assays were perfomed in tumors derived from murine xenografts in order to validate previous observations in vivo. Vitamin C dependent PDH expression and activity modulation were detected by western blot and colorimetric activity assays. Acetyl-Coa levels and citrate synthase activity were assessed using colorimetric/fluorometric activity assays. Mitochondrial membrane potential (Δψ) and cell ATP levels were assayed using fluorometric and luminescent test. Results: PDK-1 in KRAS mutant CRC cells and murine xenografts was downregulated using pharmacological doses of vitamin C through the proline hydroxylation (Pro402) of the Hypoxia inducible factor-1(HIF-1)α, correlating with decreased expression of the glucose transporter 1 (GLUT-1) in both models. Vitamin C induced remarkable ATP depletion, rapid mitochondrial Δψ dissipation and diminished pyruvate dehydrogenase E1-α phosphorylation at Serine 293, then boosting PDH and citrate synthase activity. Conclusion: We report a striking and previously non reported role of vitamin C in the regulation of the pyruvate dehydrogenase (PDH) activity, then modulating the TCA cycle and mitochondrial metabolism in KRAS mutant colon cancer. Potential impact of vitamin C in the clinical management of anti-EGFR chemoresistant colorectal neoplasias should be further considered.

The MEGA Project: A Study of the Mechanisms Involved in the Genesis and Disease Course of Asthma. Asthma Cohort Creation and Long-Term Follow-Up. / Estudio de los mecanismos implicados en la génesis y evolución del asma (proyecto MEGA): creación y seguimiento a largo plazo de una cohorte de pacientes asmáticos.

The general aim of this study is to create a cohort of asthma patients with varying grades of severity in order to gain greater insight into the mechanisms underlying the genesis and course of this disease. The specific objectives focus on various studies, including imaging, lung function, inflammation, and bronchial hyperresponsiveness, to determine the relevant events that characterize the asthma population, the long-term parameters that can determine changes in the severity of patients, and the treatments that influence disease progression. The study will also seek to identify the causes of exacerbations and how this affects the course of the disease. Patients will be contacted via the outpatient clinics of the 8 participating institutions under the auspices of the Spanish Respiratory Diseases Networking System (CIBER). In the inclusion visit, a standardized clinical history will be obtained, a clinical examination, including blood pressure, body mass index, complete respiratory function tests, and FENO will be performed, and the Asthma Control Test (ACT), Morisky-Green test, Asthma Quality of Life Questionnaire (Mini AQLQ), the Sino-Nasal Outcome Test 22 (SNOT-22), and the Hospital Anxiety and Depression scale (HADS) will be administered. A specific electronic database has been designed for data collection. Exhaled breath condensate, urine and blood samples will also be collected. Non-specific bronchial hyperresponsiveness testing with methacholine will be performed and an induced sputum sample will be collected at the beginning of the study and every 24 months. A skin prick test for airborne allergens and a chest CT will be performed at the beginning of the study and repeated every 5 years.

Thymic stromal lymphopoietin, IL-33, and periostin in hospitalized infants with viral bronchiolitis.

Much attention has recently been focused on thymic stromal lymphopoietin (TSLP), IL-33, and periostin in allergic disease, but less is known about their role in viral bronchiolitis.The aim of the study was to investigate whether infants exhibit enhanced nasal airway secretion of TSLP, IL-33, and periostin during natural respiratory viral bronchiolitis compared to healthy controls.In total, 213 infants < 2 years of age, hospitalized with bronchiolitis from October/2013 to April/2016 were enrolled alongside 45 healthy infants. Nasopharyngeal aspirates (NPA) were screened for respiratory viruses by the polymerase chain reaction. TSLP, IL-33, and periostin were measured in NPAs. Clinical data were recorded.At least 1 virus was detected in 186 (87.3%) hospitalized infants: 149 (70%) respiratory syncytial virus (RSV); 42 (19.7%) rhinovirus (HRV); 16 (7.5%) parainfluenza virus (PIV); 9 (4.2%) adenovirus; 10 (4.7%) bocavirus; and 7 (3.3%) metapneumovirus (hMPV). Infants with bronchiolitis had higher levels of TSLP (P = .02), IL-33 (P<.001), and periostin (P = .003) than healthy controls.Detectable levels of TSLP and periostin were more frequent in virus-positive than in virus-negative patients (P = .05). TSLP and IL-33 were also more common in coinfections, mainly RSV and HRV, than in single-infections (P < .05). No patient with bronchiolitis but with negative viral detection had detectable levels of nasal TSLP or IL-33. Infants with hospital stay ≥5 days were more likely to have detectable levels of nasal TSLP and periostin after adjusting by age (P = .01).Bronchiolitis by common respiratory viruses is associated with elevated nasal levels of TSLP, IL-33, and periostin, factors known to be important in the development of Th2-response. Respiratory viruses in early life might shift immune responses toward Th2, involving asthma, and allergic diseases.

Exosomes from eosinophils autoregulate and promote eosinophil functions.

Eosinophils are able to secrete exosomes that have an undefined role in asthma pathogenesis. We hypothesized that exosomes released by eosinophils autoregulate and promote eosinophil function. Eosinophils of patients with asthma (n = 58) and healthy volunteers (n = 16) were purified from peripheral blood, and exosomes were isolated and quantified from eosinophils of the asthmatic and healthy populations. Apoptosis, adhesion, adhesion molecules expression, and migration assays were performed with eosinophils in the presence or absence of exosomes from healthy and asthmatic individuals. Reactive oxygen species (ROS) were evaluated by flow cytometry with an intracellular fluorescent probe and nitric oxide (NO) and a colorimetric kit. In addition, exosomal proteins were analyzed by mass spectrometry. Eosinophil-derived exosomes induced an increase in NO and ROS production on eosinophils. Moreover, exosomes could act as a chemotactic factor on eosinophils, and they produced an increase in cell adhesion, giving rise to a specific augmentation of adhesion molecules, such as ICAM-1 and integrin α2. Protein content between exosomes from healthy and asthmatic individuals seems to be similar in both groups. In conclusion, we found that exosomes from the eosinophils of patients with asthma could modify several specific eosinophil functions related to asthma pathogenesis and that they could contribute fundamentally to the development and maintenance of asthma.