The role of phagocytic NADPH oxidase and innate immune cells in the immune activation in toluene diisocyanate-induced lung inflammation

摘要

Isocyanates are low-molecular-weight compounds noted for inducing an oxidant stress-dependent pulmonary inflammation which is the leading cause of occupational asthma The occupational asthma is characterized by variable airflow limitation and airway hyperresponsiveness due to causes and conditions attributable to a particular occupational environment and not to stimuli encountered outside the workplace Oxidant stress mediated by reactive oxygen species (ROS) including superoxide singlet oxygen (O ) H2O2 and hydroxyl radical (-OH) has been known to be important in the immunopathogenesis of the lung which is exposed to a higher concentration of oxygen than is most other tissue The phagocyte NADPH oxidase (NOX2) which is highly expressed in phagocytes such as neutrophils and monocytes is usually the most active producer of ROS in inflammatory tissues Our previous studies indicated that phagocytic NADPH oxidase is an essential regulator in TDI-induced airway inflammation characterized by a server lung inflammation with both Th17 and Th2 immune components Change of redox balance by antioxidants or defective phagocyte oxidase may affect the lung inflammation in terms of early innate immune cell activation/ recruitment and the subsequent specific immune responses Innate lymphoid cells (ILCs) have been known to play an important role in the development of lymphoid tissues and in the initiation of inflammation at barrier surfaces in response to infection or tissue damage In this study we hypothesized that ILCs activation may play an important role in phagocytic NADPH oxidase-mediated downstream immune mechanism in TDI-induced airway inflammation The wild type and phagocytic NADPH oxidase 2 deficient (NOX2 deficiency; Ncf1-/-) mice were sensitized and challenged with 3% TDI to induce lung inflammation First we tested the effects of TDI on allergic airway inflammation in wild type and NOX2 deficiency (Ncf1-/-) mice We found that TDI exposure induced airway hyperresponsiveness in wild type but not in Ncf1-/- mice In the effects of TDI on the induction of cytokines production type 2 inflammatory cytokines including IL-33 and IL-5 increased in both WT and Ncf1-/- mice but more significantly in TDI-induced lung inflammation Moreover the pro-inflammatory cytokine IL-1β and IL-17A production was only induced by TDI-exposure in wild type but not in Ncf1-/- mice The relative abundance of ILC subsets tended to change in TDI-induced wild type and Ncf1-/- mice We identified the population of lineage negative and CD45 positive cells in inflammation lung tissue Comparison of ILCs population between TDI-induced wild type mice and Ncf1-/- mice showed that the number of ILC2s and ILC3s were significantly higher in wild type mice To investigate whether ROS affect more NCR- ILC3 population in TDI-induced lung inflammation through stimulating ILC3 upstream cytokines production we purified the NCR- ILC3 which were sorted from the inflammatory lung tissue of TDI-induced wild type and Ncf1-/- mice and stimulated with recombined protein IL-1β in cell culture We found that IL-1β stimulation induced change of exILC3 phenotype to NCR- ILC3 which produce more IL-17A Moreover in the case of IL-1β and IL-23 combined stimulation the change of exILC3 phenotype to NCR- ILC3 was more pronounced These results suggested that ROS may modulate the activation of ILC2s ILC3s and may determine the Th2 and Th17 cytokines production in the TDI-induced lung inflammation

獎項日期	2017 7月 20
原文	English
監督員	Chi-Chang Shieh (Supervisor)