The Studies On Asthma Immunoprevention And The Mechanism Of Acute Lung Injury

Interleukin-28A(IL-28A)modulates CD11c+ dendritic cell(DC)function and promotes type 1 T helper(Th1)differentiation,thus suppressing allergic airway diseases.However,the function of the IL-28 A isoform IL-28 B in these diseases remains largely unknown.In this study,we revealed a novel role of IL-28 B in inducing type 1 immunity and protecting against ovalbumin(OVA)-induced allergic asthma in mice.IL-28 B overexpression in wild-type mice promoted natural killer(NK)cell polarization in the lung,leading to the increased number of interferon(IFN)-?-producing NK1 cells as well as Th1 differentiation.Importantly,IL-28 B overexpression had no protective effect on OVA-induced asthma in IFN-?-knockout(IFN-?-/-)mice.These results demonstrate that IL-28 B ameliorates experimental allergic asthma via enhancing NK cell polarization,which might be useful for prevention and treatment of allergic asthma.Through the methods as above mentioned,we get the major results as following: 1?Overexpression of IL-28 B inhibited OVA-induced allergic asthma in mice.IL-28 B was stably overexpressed in serum and BALF for at least 17 days.Importantly,compared with control group,overexpression of IL-28 B significantly inhibited OVA-induced allergic asthma as evidenced by the marked decrease in the numbers of eosinophils,neutrophils and lymphocytes as well as Ig E production and airway resistance in the mouse lung.Consistently,the reduced leukocyte infiltration was also observed in the peribronchial areas.In addition,overexpression of IL-28 B greatly suppressed OVA-induced goblet cell hyperplasia and mucus hypersecretion in airway epithelium.These data suggest that IL-28 B plays an inhibitory role in OVA-induced airway inflammation.2?Overexpression of IL-28 B increased the number and frequency of NK cells in OVA-challenged mouse lungs.IL-28 B significantly increased the number and percentage of NK cells in OVA-challenged lungs.3?NK cells mediated IL-28B-suppressed airway inflammationAs GM1 injection significantly increased the frequency and numbers of eosinophils,neutrophils,and lymphocytes in BALF as well as Ig E production and airway resistance in the mouse lung compared with control group,as well as greatly promoting the leukocyte infiltration in the peribronchial areas.Furthermore,As GM1 injection markedly enhanced IL-28B-suppressed goblet cell hyperplasia and mucus hypersecretion in airway epithelium.4?IL-28 B inhibition of OVA-induced airway inflammation depended on IFN-?IL-28 B overexpression resulted in significant increase in the number of IFN-?-producing NK cells.In IFN-?-/-mice,IL-28 B overexpression had no effects on the numbers of eosinophils,neutrophils,and lymphocytes in BALF as well as Ig E production and airway resistance in the mouse lung compared with control plasmid or PBS group.Consistent with this finding,there was no significant changes in the degree of leukocyte infiltration into the peribronchial areas,airway goblet cell hyperplasia and mucus hypersecretion.Paraquat is a poisoning herbicide that primarily targets lung,leading to severe acute lung injury characterized by extensive neutrophil infiltration.However,the mechanisms underlying the neutrophil infiltration is not clear.In this study,we demonstrated the significance of the signaling cascade from high-mobility group box 1(HMGB1),to Toll-like receptor 4(TLR4),interleukin-23(IL-23),and lastly to IL-17 A during the paraquat-induced neutrophil infiltration and the subsequent lung injury in mice.Paraquat challenge significantly elevated serum levels of IL-17 A and IL-23,the percentage of IL-17A-producing gdT cells in the lung,and the level of HMGB1 in bronchoalveolar lavage fluid.Reducing IL-17 A production using an anti-gdT antibody,targeting IL-23 with the neutralizing antibody against IL-23p19,and blocking HMGB1 signaling by using glycyrrhizin or TLR4-/-mice all dramatically inhibited the infiltration of neutrophils and attenuated lung injury.These novel findings not only reveal the critical role of HMGB1-TLR4-IL-23-IL-17 A axis in the pathogenesis of paraquat-induced acute lung injury,but also provide promising therapeutic targets for treating paraquat poisoning.Through the methods as above mentioned,we get the major results as following: 1?PQ gavage induces ALI in mice.PQ at the dose of 40 mg/kg could induce acute lung injury.all parameters examined,including the W/D ratio,total protein level in BALF,and MPO activity were significantly elevated in PQ-challenged mice,compared to PBS-challenged control mice.On the cellular level,PQ at the dose of 40 mg/kg significant increase of total neutrophils in the lung tissue,compared to the corresponding levels in PBS-challenged mice and more severe lung damage in PQ-challenged mice.2?IL17A critically controls PQ-induced ALI.The serum IL-17 A level increased in a time-dependent manner following PQ challenge.In addition,the IL-17 A expression was significantly up-regulated in the lung tissue at 72 h after PQ challenge,when compared to the level in the lungs from PBS-challenged mice,suggesting the injured lung tissue could be a source for serum IL17 A following PQ challenging.pre-treatment of mice with IL17 A blocking antibody dramatically alleviated pathological changes associated with PQ-induced ALI,as demonstrated by significant reductions in the W/D ratio,MPO activity,and the percentage as well as number of neutrophils infiltrating into the lung tissues.3?The pulmonary ?? T cells are a significant source for IL-17 A.??T cells increased from approximately 10% to more than 20% at 72 h after PQ challenge while the percentage of Th17 cells did not significantly change.After the mice were pre-treated with anti-??TCR antibody to deplete in vivo ?? T cells,the level of serum IL-17 A in response to PQ challenge was significantly reduced.In addition to inhibition of serum IL-17 A level,depletion of ?? T cells also decreases the W/D ratio,MPO activity,the number of infiltrating neutrophils in the lung tissues,as well as attenuated histological injury.4?IL-23 is required for the production of IL-17 A from ?? T cells.When blocking the endogenous IL-23 with the neutralizing antibody targeting the p19 subunit,both the serum IL-17 A level and the number of neutrophils infiltrating into the lung tissue,as well as attenuated histological injury were significantly reduced,as compared to mice pre-treated with isotype-matched rat Ig G.5?HMGB1 signals through TLR4 to promote the release of IL-23 in response to PQ challenge.The amount of HMGB1 increased in a time-dependent manner in PQ-challenged mice,correlated with the level in BALF.When the mice were pre-treated with HMGB1 inhibitor,glycyrrhizin,the serum levels of IL-23,IL-17 A,as well as the number of infiltrating neutrophils in the lung tissue were all significantly inhibited.To assess the significance of TLR4 in the activation of IL-23-IL-17 A axis in response to PQ challenge,we administered PQ to either TLR4-/-or wild-type(WT;as controls)C57BL6 mice.We found that the serum levels of IL-23 and IL-17 A were significantly lower in TLR4-/-mice than in WT mice,which was associated with dramatically lower number of neutrophils in the lung tissue and improved changes on histology.