Anti-CLCA1 monoclonal antibody, clone 2D5

Repeated inhalation of airborne conidia derived from the fungusAspergillus fumigatus(Af) can lead to a severe eosinophil-dominated inflammatory condition of the lung termed allergic bronchopulmonary aspergillosis (ABPA). ABPA affects about 5 million individuals worldwide and the mechanisms regulating lung pathology in ABPA are poorly understood. Here, we used a mouse model of ABPA to investigate the role of eosinophils and T cell-derived IL-4/IL-13 for induction of allergic lung inflammation. Selective deletion of IL-4/IL-13 in T cells blunted theAf-induced lung eosinophilia and further resulted in lower expression of STAT6-regulated chemokines and effector proteins such as Arginase 1, Relm-alpha, Relm-beta, and Muc5a/c. Eosinophil-deficient Delta dblGata mice showed lower IL-4 expression in the lung and the number of Th2 cells in the lung parenchyma was reduced. However, expression of the goblet cell markers Clca1 and Muc5a/c, abundance of mucin-positive cells, as well as weight gain of lungs were comparable betweenAf-challenged Delta dblGata and WT mice. Based on these results, we conclude that T cell-derived IL-4/IL-13 is essential forAf-induced lung eosinophilia and inflammation while eosinophils may play a more subtle immunomodulatory role and should not simply be regarded as pro-inflammatory effector cells in ABPA.

Mucus hypersecretion and goblet cell hyperplasia are common features that characterize asthma. IL-13 increases mucin (MUC) SAC, the major component of airway mucus, in airway epithelial cells. According to the literature, IL-13 receptor activation leads to STATE activation and consequent induction of chloride channel accessory 1 (CLCA1) gene expression, associated with the induction of MUC_5AC. Heme oxygenase-1 (HO-1) is an enzyme that catalyzes oxidation of heme to biliverdin, and has anti-inflammatory and anti-oxidant properties. We examined the effects of HO-1 on mucin production and goblet cell hyperplasia induced by IL-13. Moreover, we assessed the cell signaling intermediates that appear to be responsible for mucin production. Normal human bronchial epithelial (NHBE) cells were grown at air liquid interface (ALI) in the presence or absence of IL-13 and hemin, a HO-1 inducer, for 14 days. Protein concentration was analyzed using ELISA, and mRNA expression was examined by real-time PCR. Histochemical analysis was performed using HE staining, and Western blotting was performed to evaluate signaling transduction pathway. Hemin (4 mu M) significantly increased HO-1 protein expression (p < 0.01) and HO-1 mRNA expression (p < 0.001). IL-13 significantly increased goblet cells, MUC5AC protein secretion (p < 0.01) and MUC5AC mRNA (p < 0.001), and these were decreased by hemin by way of HO-1. Tin protoporphyrin (SnPP)-IX, a HO-1 inhibitor, blocked the effect of hemin restoring MUC5AC protein secretion (p <0.05) and goblet cell hyperplasia. Hemin decreased the expression of CLCA1 mRNA (p <0.05) and it was reversed by SnPP-IX, but could not suppress IL-13-induced phosphorylation of STAT6 or SAM pointed domain-containing EIS transcription factor (SPDEF) and Forkhead box A2 (FOXA2) mRNA expression. In summary, HO-1 overexpression suppressed IL-13-induced goblet cell hyperplasia and MUC5AC production, and involvement of CLCA1 in the mechanism was suggested. (C) 2015 Elsevier B.V. All rights reserved.