Kita, Hirohito

Background Recent investigations suggest that inflammation and autoimmunity might have a role in the pathophysiology of atrial fibrillation (AF). Given that abnormal ventriculovascular coupling often coexists with AF, we hypothesize that autoimmune vasculitis plays a significant role in the pathogenetic mechanism of AF. Methods and Results A standardized retrospective population‐based case–control study was conducted to evaluate the association between autoimmune vasculitis and AF, and all‐cause mortality. The study included 8459 patients with a new diagnosis of AF and 8459 age‐, sex‐, and registration calendar year–matched controls in Olmsted County, Minnesota, between January 1, 1980 and December 31, 2010. The association of each clinical characteristic, diagnosis, and treatment was assessed using conditional logistic regression to account for the matched case–control study design. Cox proportional hazards regression models and Kaplan‐Meier curves were used to detect independent predictors of mortality and examine cumulative survival. Of a total of 16 918 patients (mean age 72.3+14.4 years; 48.7% women), 320 (1.9%) were diagnosed with autoimmune vasculitis before the index date during the 30‐year period. Among the cases, the prevalence of any autoimmune vasculitis was 2.3%, whereas the frequency of autoimmune vasculitis in controls was 1.5% ( P <0.001). After adjusting for potential confounders, the odds of autoimmune vasculitis in AF cases was 1.5 times higher than in controls (odds ratio, 1.47; 95% CI, 1.04–2.01; P =0.03). Patients with AF and autoimmune vasculitis had worse 5‐year survival than those without autoimmune vasculitis or AF (44.7% versus 77.2%; log‐rank P <0.001). Conclusions Autoimmune vasculitis is significantly associated with AF and independently confers worse survival. These observations may represent one mechanism linking autoimmunity and inflammation to the pathogenesis and prognosis of AF.

Abstract The cyclooxygenase (COX) metabolic pathway regulates immune responses and inflammation. The effect of the COX pathway on innate pulmonary inflammation induced by protease-containing fungal allergens, such as Alternaria alternata, is not fully defined. In this study, we tested the hypothesis that COX inhibition augments Alternaria-induced pulmonary group 2 innate lymphoid cell (ILC2) responses and IL-33 release. Mice were treated with the COX inhibitors indomethacin, flurbiprofen, or vehicle and challenged intranasally with Alternaria extract for four consecutive days to induce innate lung inflammation. We found that indomethacin and flurbiprofen significantly increased the numbers of ILC2 and IL-5 and IL-13 expression by ILC2 in the lung. Indomethacin also increased ILC2 proliferation, the percentages of eosinophils, and mucus production in the lung. Both indomethacin and flurbiprofen augmented the release of IL-33 in bronchoalveolar lavage fluid after Alternaria challenge, suggesting that more IL-33 was available for ILC2 activation and that a COX product(s) inhibited IL-33 release. This is supported by the in vitro finding that the COX product PGE2 and the PGI2 analogs cicaprost decreased Alternaria extract–induced IL-33 release by human bronchial epithelial cells. Although contrasting effects of PGD2, PGE2, and PGI2 on ILC2 responses have been previously reported, the overall effect of the COX pathway on ILC2 function is inhibitory in Alternaria-induced innate airway inflammation.

Abstract Background Group 2 innate lymphoid cells (ILC2) are stimulated by IL‐33 to increase IL‐5 and IL‐13 production and airway inflammation. While sex hormones regulate airway inflammation, it remained unclear whether estrogen signaling through estrogen receptor‐α (ER‐α, Esr1 ) or ER‐β ( Esr2 ) increased ILC2‐mediated airway inflammation. We hypothesize that estrogen signaling increases allergen‐induced IL‐33 release, ILC2 cytokine production, and airway inflammation. Methods Female Esr1 ‐/‐ , Esr2 ‐/‐ , wild‐type (WT), and IL33 fl/fl eGFP mice were challenged with Alternaria extract (Alt Ext) or vehicle for 4 days. In select experiments, mice were administered tamoxifen or vehicle pellets for 21 days prior to challenge. Lung ILC2, IL‐5 and IL‐13 production, and BAL inflammatory cells were measured on day 5 of Alt Ext challenge model. Bone marrow from WT and Esr1 ‐/‐ female mice was transferred (1:1 ratio) into WT female recipients for 6 weeks followed by Alt Ext challenge. hBE33 cells and normal human bronchial epithelial cells (NHBE) were pretreated with 17β‐estradiol (E2), propyl‐pyrazole‐triol (PPT, ER‐α agonist), or diarylpropionitrile (DPN, ER‐β agonist) before allergen challenge to determine IL‐33 gene expression and release, extracellular ATP release, DUOX‐1 production, and necrosis. Results Alt Ext challenged Esr1 ‐/‐ , but not Esr2 ‐/‐ , mice had decreased IL‐5 and IL‐13 production, BAL eosinophils, and IL‐33 release compared to WT mice. Tamoxifen decreased IL‐5 and IL‐13 production and BAL eosinophils. IL‐33eGFP + epithelial cells were decreased in Alt Ext challenged Esr1 ‐/‐ mice compared to WT mice. 17β‐E2 or PPT, but not DPN, increased IL‐33 gene expression, release, and DUOX‐1 production in hBE33 or NHBE cells. Conclusion Estrogen receptor ‐α signaling increased IL‐33 release and ILC2‐mediated airway inflammation.

Abstract Background: Eosinophils play an important role in allergic inflammation . Glucocorticosteroids have been used as an anti-inflammatory medication for inflammatory diseases involving eosinophil infiltration. Likewise, lidocaine, a local anaesthetic, is used to treat certain patients with asthma, which is also an inflammatory disease. The goal of this study was to examine the effects of dexamethasone and lidocaine on eosinophil proliferation and differentiation using a model of human umbilical cord blood mononuclear cells (UCMC) cultured with IL-5.Methods: UCMC were cultured with IL-5 (5 ng/mL) for 4 weeks. The effects of dexamethasone and lidocaine on the number and morphology of eosinophilic cells were visualized with Wright-Giemsa and cyanide-resistant peroxidase stains . Moreover, the effect on eosinophil-derived neurotoxin (EDN) and eosinophil peroxidase (EPX) contents in cultured cells were evaluated using radioimmunoassay.Results: The number of eosinophilic cells and EDN and EPX content in cultured cells increased in a time-dependent manner in the presence of IL-5. Dexamethasone treatment slightly decreased the number of eosinophilic cells in one week, but this effect was lost in 2–4 weeks. Macrophages in cultured cells treated with dexamethasone contained more eosinophil granule proteins when UCMC were treated with dexamethasone. Both EDN and EPX content in cultured cells were reduced by dexamethasone. Lidocaine decreased the number of eosinophilic cells and reduced both EDN and EPX contents in cultured cells. Conclusions: These findings suggest that dexamethasone suppresses eosinophil maturation while lidocaine suppresses both production and maturation. Dexamethasone may also induce apoptosis of eosinophils.

Abstract Peanut allergy is a growing public concern; however, little is known about the immunological mechanism(s) that initiate the disease process. Our knowledge is also limited regarding the role of group 2 innate lymphoid cells (ILC2s) in regulating humoral immunity. To fill these major gaps in our knowledge, we investigated the immunological mechanisms involved in peanut allergen sensitization by using mouse models. To mimic environmental exposure in humans, naive BALB/c mice were exposed to peanut flour by inhalation without any exogenous adjuvants. When exposed to peanut flour, naive mice developed T follicular helper (Tfh) cells in their lung draining lymph nodes and produced IgE Abs to peanuts. Mice deficient in IL-13 showed decreased numbers of Tfh cells and germinal center B cells and produced significantly fewer IgE Abs. IL-13 was necessary and sufficient for induction of CD11c+ MHC class IIhi dendritic cells that are implicated in Tfh cell development. Importantly, lung ILC2s served as a predominant early source of IL-13 when naive mice were exposed to peanut flour. Furthermore, mice that are deficient in lung ILC2s by bone marrow transfer from Rorasg/sg mice or by genetic manipulation produced significantly fewer IgE Abs to peanuts compared with control mice. These findings suggest lung ILC2s that serve as a rapid source of IL-13 upon allergen exposure play a major role in Tfh cell development, IgE Ab production, and initiation of peanut allergy.

Allergens derived from the common fungus Alternaria alternata induce oxidative stress in human airway epithelial (HBE) cells that leads to the regulated release of ATP and subsequent activation of P2X 7 receptors that facilitate Ca 2+ uptake into the cell. Sustained increases in [Ca 2+ ] i are required for nuclear processing and secretion of IL‐33, which initiates allergic inflammation by activating ST2 receptors on immune cells to induce Th2 cytokine secretion. Pretreatment of HBE cells with the K2P channel blockers bupivacaine or quinidine produced a significant increase in ATP release following Alternaria stimulation. This response was blocked by inhibiting ATP loading into membrane vesicles by treatment with 200 nM bafilomycin A 1 before allergen exposure. Similarly, pretreatment with the PKC inhibitor Go6976 also blocked approximately 50% of Alternaria ‐induced ATP release and completely abolished the increase in ATP release produced by pretreatment with K2P channel blockers. The effects of bupivacaine and quinidine were comparable to the effect of phorbol 12‐myristate 13‐acetate (PMA, 2 mM), a well‐characterized PKC activating compound prior to Alternaria stimulation. These results support the conclusion that K2P channel inhibition is associated with PKC activation, which functions to potentiate the effects of Alternaria allergens on vesicular ATP release. We propose that enhanced PKC activity is dependent on membrane depolarization associated with inhibition of constitutive, K2P channel mediated K + efflux from these cells. Support or Funding Information This study was supported by grants from the NIH (R01‐AI128729), awarded to HK and SMO and from the Minnesota Agriculture Experiment Station (AES‐0016097) awarded to SMO.

Key points Alternaria aeroallergens induce the release of ATP from human bronchial epithelial (HBE) cells by activating a conductive pathway involving voltage‐dependent anion channel‐1 (VDAC‐1) and by exocytosis of ATP localized within membrane vesicles. Inhibition of VDAC‐1 blocked Alternaria‐evoked Ca2+ uptake across the plasma membrane of HBE cells and interleukin (IL)‐33 release into the extracellular media. Reducing cholesterol content with a cholesterol scavenger (β‐methylcyclodextrin) or statin compound (simvastatin) blocked ATP and IL‐33 release by lowering the expression of VDAC‐1 in the plasma membrane. Pretreatment with simvastatin for 24 h also inhibited the increase in tight junction macromolecule permeability that occurs following Alternaria exposure. These results establish a novel role for VDAC‐1 as a mechanism underlying ATP release induced by fungal allergens and suggests a possible therapeutic use for cholesterol lowering compounds in reducing Alternaria‐stimulated allergic inflammation. AbstractHuman bronchial epithelial (HBE) cells exposed to allergens derived from the common saprophytic fungus, Alternaria alternata release ATP, which in turn stimulates P2X7 receptor‐mediated Ca2+ uptake across the plasma membrane. The subsequent increase in intracellular calcium concentration induces proteolytic processing and secretion of interleukin (IL)‐33, a critical cytokine involved in the initiation of allergic airway inflammation. A major objective of the present study was to identify the mechanism responsible for conductive ATP release. The results show that pretreatment of HBE cells with inhibitors of the voltage‐dependent anion channel‐1 (VDAC‐1) or treatment with a VDAC‐1 selective blocking antibody or silencing mRNA expression of the channel by RNA interference, inhibit Alternaria‐evoked ATP release. Moreover, inhibition of VDAC‐1 channel activity or reducing protein expression blocked the secretion of IL‐33. Similarly, reducing the cholesterol content of HBE cells with simvastatin or the cholesterol scavenger β‐methylcyclodextrin also blocked ATP release and IL‐33 secretion by decreasing the level of VDAC‐1 expression in the plasma membrane. In addition, simvastatin inhibited the increase in tight junction macromolecule permeability that was previously observed after Alternaria exposure. These results demonstrate a novel function for VDAC‐1 as the conductive mechanism responsible for Alternaria‐induced ATP release, an essential early step in the processing, mobilization and secretion of IL‐33 by the airway epithelium. Furthermore, the simvastatin‐evoked reduction of VDAC‐1 expression in the plasma membrane, suggests the possibility that cholesterol lowering compounds may be beneficial in alleviating allergic airway inflammation induced by fungal allergens.

Introduction The lack of effective, consistent, reproducible and efficient asthma ascertainment methods results in inconsistent asthma cohorts and study results for clinical trials or other studies. We aimed to assess whether application of expert artificial intelligence (AI)-based natural language processing (NLP) algorithms for two existing asthma criteria to electronic health records of a paediatric population systematically identifies childhood asthma and its subgroups with distinctive characteristics. Methods Using the 1997–2007 Olmsted County Birth Cohort, we applied validated NLP algorithms for Predetermined Asthma Criteria (NLP-PAC) as well as Asthma Predictive Index (NLP-API). We categorised subjects into four groups (both criteria positive (NLP-PAC+/NLP-API+); PAC positive only (NLP-PAC+ only); API positive only (NLP-API+ only); and both criteria negative (NLP-PAC−/NLP-API−)) and characterised them. Results were replicated in unsupervised cluster analysis for asthmatics and a random sample of 300 children using laboratory and pulmonary function tests (PFTs). Results Of the 8196 subjects (51% male, 80% white), we identified 1614 (20%), NLP-PAC+/NLP-API+; 954 (12%), NLP-PAC+ only; 105 (1%), NLP-API+ only; and 5523 (67%), NLP-PAC−/NLP-API−. Asthmatic children classified as NLP-PAC+/NLP-API+ showed earlier onset asthma, more Th2-high profile, poorer lung function, higher asthma exacerbation and higher risk of asthma-associated comorbidities compared with other groups. These results were consistent with those based on unsupervised cluster analysis and lab and PFT data of a random sample of study subjects. Conclusion Expert AI-based NLP algorithms for two asthma criteria systematically identify childhood asthma with distinctive characteristics. This approach may improve precision, reproducibility, consistency and efficiency of large-scale clinical studies for asthma and enable population management.