ABSTRACT
Polyethyleneimine (PEI) induced immune responses were investigated in human bronchial epithelial (hBE) cells and mice. PEI rapidly induced ATP release from hBE cells and pretreatment with glutathione (GSH) blocked the response. PEI activated two conductive pathways, VDAC-1 and pannexin 1, which completely accounted for ATP efflux across the plasma membrane. Moreover, PEI increased intracellular Ca2+ concentration ([Ca2+]i), which was reduced by the pannexin 1 inhibitor, 10Panx (50 µM), the VDAC-1 inhibitor, DIDS (100 µM), and was nearly abolished by pretreatment with GSH (5 mM). The increase in [Ca2+]i involved Ca2+ uptake through two pathways, one blocked by oxidized ATP (oATP, 300 µM) and another that was blocked by the TRPV-1 antagonist A784168 (100 nM). PEI stimulation also increased IL-33 mRNA expression and protein secretion. In vivo experiments showed that acute (4.5 h) PEI exposure stimulated secretion of Th2 cytokines (IL-5 and IL-13) into bronchoalveolar lavage (BAL) fluid. Conjugation of PEI with ovalbumin also induced eosinophil recruitment and secretion of IL-5 and IL-13 into BAL fluid, which was inhibited in IL-33 receptor (ST2) deficient mice. In conclusion, PEI-induced oxidative stress stimulated type 2 immune responses by activating ATP-dependent Ca2+ uptake leading to IL-33 secretion, similar to allergens derived from Alternaria.
Subject(s)
Adenosine Triphosphate/immunology , Epithelial Cells/drug effects , Epithelial Cells/immunology , Immunity/drug effects , Nanoparticles/administration & dosage , Oxidative Stress/drug effects , Polyethyleneimine/pharmacology , Allergens/immunology , Animals , Calcium/immunology , Cells, Cultured , Cytokines/immunology , Female , Humans , Immunity/immunology , Mice , Mice, Inbred BALB C , Oxidative Stress/immunology , RNA, Messenger/immunology , Respiratory Mucosa/drug effects , Respiratory Mucosa/immunologyABSTRACT
Spirometry is a crucial test used in the diagnosis and monitoring of patients with chronic obstructive pulmonary disease (COPD). Severe acute respiratory syndrome coronavirus 2 pandemic has posed numerous challenges in performing spirometry. Dynamic-ventilatory digital radiography (DR) provides sequential chest radiography images during respiration with lower doses of radiation than conventional X-ray fluoroscopy and computed tomography. Recent studies revealed that parameters obtained from dynamic DR are promising for evaluating pulmonary function of COPD patients. We report two cases of COPD evaluated by dynamic-ventilatory DR for pulmonary function and treatment efficacy and discuss the potential of dynamic DR for evaluating COPD therapy.