ag-490 and Asthma

Objective To observe the effect of lipid derivative of benzylidene malononitrile AG490 on the airway inflammation in a mouse model of neutrophilic asthma (NA). Methods Fifty-four specific pathogen-free (SPF) female C57BL/6 mice were randomly divided into 3 groups: NA group, AG490-treated NA (NAAG) group, and normal control (NC) group, 18 mice in each group. The NA group and the NAAG group were sensitized by airway instillation of ovalbumin (OVA) and lipopolysaccharide (LPS) on day 0, 6 and 13. The NAAG group was injected with AG490 (500 μg/mouse, i.p.) three times a week, from day 0 after the first sensitization, for 3 weeks. Mice were challenged on day 21, 22 for 1 hour/time with an aerosol of 10 g/L OVA. At 24 hours after the final challenge, bronchoalveolar lavage fluid (BALF) was collected. The total number and differential counts of nucleated cells and the percentage of each type were determined. HE staining and PAS staining was employed for observing the lung pathological changes. The percentages of Th17 cells and regulatory T cells (Treg) in the lung issue were determined by flow cytometry. The level of interleukin-17 (IL-17) in BALF was measured using ELISA. Results Compared with the NA group, the total number of nucleated cells, the percentage of neutrophils and the percentage of eosinophils in BALF in the NAAG group were obviously reduced; lung tissue pathologic changes were improved in the NAAG group; goblet cell hyperplasia and the level of IL-17 in BALF in the NAAG group were significantly down-regulated; the proportion of Treg in the lung increased and the proportion of Th17 cells in the lung decreased in the NAAG group. Conclusion After NA mice are treated with AG490 during the sensitization phase, the proportion of Treg in the lung would increase and the proportion of Th17 cells in the lung would decrease. AG490 could attenuate the airway inflammation in the mouse model of NA.

Topics: Animals; Asthma; Bronchoalveolar Lavage Fluid; Enzyme Inhibitors; Female; Flow Cytometry; Inflammation; Interleukin-17; Lipids; Lipopolysaccharides; Lung; Mice, Inbred C57BL; Neutrophils; Ovalbumin; Random Allocation; Respiratory System; Th17 Cells; Tyrphostins

Leukemia inhibitory factor (LIF), a cytokine at the interface between neurobiology and immunology, is mainly mediated through JAK/STAT pathway and MAPK/ERK pathway. Evidence suggested LIF is related to the higher expression of neurokinin-1 receptor (NK-1R) in asthma. In this study, the immunohistochemistry stain showed the expressions of NK-1R, LIF, p-STAT3, and p-ERK1/2 in the lung tissues of allergic rats were increased compared with the controls, and the main positive cell type was airway epithelial cell. Normal human bronchial epithelial cells were treated with LIF in the presence or absence of AG490 (JAK2 inhibitor), PD98059 (MEK inhibitor), and the siRNA against STAT3. Western blot and RT-PCR indicated that LIF induced the expression of NK-1R, which was inhibited by the inhibitors mentioned above. No significant interaction was found between JAK/STAT pathway and MAPK/ERK pathway. In summary, bronchial epithelial cell changes in asthma are induced by LIF which promotes the expression of NK-1R, and JAK/STAT pathway and MAPK/ERK pathway may participate in this process.

Topics: Animals; Asthma; Base Sequence; Bronchi; Cells, Cultured; Epithelial Cells; Flavonoids; Humans; Janus Kinases; Leukemia Inhibitory Factor; Male; MAP Kinase Signaling System; Rats; Rats, Sprague-Dawley; Receptors, Neurokinin-1; Recombinant Proteins; RNA, Small Interfering; STAT Transcription Factors; STAT3 Transcription Factor; Tetradecanoylphorbol Acetate; Tyrphostins; Up-Regulation

We studied the effect of tyrphostin AG-490, a specific Janus kinase 2 (JAK2) inhibitor, on antigen-induced eosinophil recruitment into the airways of sensitized mice and on IL-5-induced chemokinesis and adhesiveness of eosinophils. The in vivo administration of AG-490 prevented antigen-induced eosinophil infiltration in the airways of sensitized mice in a dose-dependent manner. However, the administration of AG-490 did not affect antigen-induced IL-5 production in the airways nor in vitro antigen-induced IL-5 production and T cell proliferation of spleen cells. Furthermore, AG-490 inhibited IL-5-induced chemokinesis and beta1-integrin adhesiveness of eosinophils in vitro. Because antigen-induced eosinophil recruitment into the airways is mediated by IL-5, these results indicate that JAK2 activation is critical for antigen-induced, IL-5-dependent mobilization of eosinophils into the tissue.

Topics: Animals; Anti-Allergic Agents; Asthma; Bronchoalveolar Lavage Fluid; Cell Adhesion; Chemotaxis, Leukocyte; Eosinophils; Female; Humans; Integrin alpha4beta1; Integrins; Interleukin-5; Janus Kinase 2; Mice; Mice, Inbred BALB C; Ovalbumin; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Receptors, Lymphocyte Homing; Tyrphostins