AMG487 alleviates influenza A (H1N1) virus-induced pulmonary inflammation through decreasing IFN-γ-producing lymphocytes and IFN-γ concentrations.

BACKGROUND AND PURPOSE: Severe influenza virus-infected patients have high systemic levels of Th1 cytokines (including IFN-γ). Intrapulmonary IFN-γ increases pulmonary IFN-γ-producing T lymphocytes through the CXCR3 pathway. Virus-infected mice lacking IP-10/CXCR3 demonstrate lower pulmonary neutrophilic inflammation. AMG487, an IP-10/CXCR3 antagonist, ameliorates virus-induced lung injury in vivo through decreasing viral loads. This study examined whether AMG487 could treat H1N1 virus-induced mouse illness through reducing viral loads or decreasing the number of lymphocytes or neutrophils. EXPERIMENTAL APPROACH: Here, we studied the above-mentioned effects and underlying mechanisms in vivo. KEY RESULTS: H1N1 virus infection caused bad overall condition and pulmonary inflammation characterized by the infiltration of lymphocytes and neutrophils. From Day-5 to Day-10 post-virus infection, bad overall condition, pulmonary lymphocytes, and IFN-γ concentrations increased, while pulmonary H1N1 viral titres and neutrophils decreased. Both anti-IFN-γ and AMG487 alleviated virus infection-induced bad overall condition and pulmonary lymphocytic inflammation. Pulmonary neutrophilic inflammation was mitigated by AMG487 on Day-5 post-infection, but was not mitigated by AMG487 on Day-10 post-infection. H1N1 virus induced increases of IFN-γ, IP-10, and IFN-γ-producing lymphocytes and activation of the Jak2-Stat1 pathways in mouse lungs, which were inhibited by AMG487. Anti-IFN-γ decreased IFN-γ and IFN-γ-producing lymphocytes on Day-5 post-infection. AMG487 but not anti-IFN-γ decreased viral titres in mouse lung homogenates or BALF. Higher virus load did not increase pulmonary inflammation and IFN-γ concentrations when mice were treated with AMG487. CONCLUSION AND IMPLICATIONS: AMG487 may ameliorate H1N1 virus-induced pulmonary inflammation through decreasing IFN-γ-producing lymphocytes rather than reducing viral loads or neutrophils.

Sputum Transcriptomics Reveals FCN1+ Macrophage Activation in Mild Eosinophilic Asthma Compared to Non-Asthmatic Eosinophilic Bronchitis.

PURPOSE: Eosinophilic asthma (EA) and non-asthmatic eosinophilic bronchitis (EB) share similar eosinophilic airway inflammation. Unlike EA, EB did not present airway hyperresponsiveness or airflow obstruction. We aimed to compare the mechanism underlying the different manifestations between EA and EB via sputum transcriptomics analysis. METHODS: Induced-sputum cells from newly physician-diagnosed EA, EB patients, and healthy controls (HCs) were collected for RNA sequencing. RESULTS: Bulk RNA sequencing was performed using sputum cells from patients with EA (n = 18), EB (n = 15) and HCs (n = 28). Principal component analysis revealed similar gene expression patterns in EA and EB. The most differentially expressed genes in EB compared with HC were also shared by EA, including IL4, IL5 IL13, CLC, CPA3, and DNASE1L3. However, gene set enrichment analysis showed that the signatures regulating macrophage activation were enriched in EA compared to EB. Sputum cells were profiled using single-cell RNA sequencing. FABP4+ macrophages, SPP1+ macrophages, FCN1+ macrophages, dendritic cells, T cells, B cells, mast cells, and epithelial cells were identified based on gene expression profiling. Analysis of cell-cell communication revealed that interactions between FCN1+ macrophages and other cells were higher in EA than in EB. A wealth of transforming growth factor beta (TGF-ß) and vascular endothelial growth factor (VEGF) interactions between FCN1+ macrophages and other cells have been shown in EA. The gene expression levels of EREG, TGFBI, and VEGFA in FCN1+ macrophages of EA were significantly higher than those of EB. Furthermore, signatures associated with the response to TGF-ß, cellular response to VEGF stimulus and developmental cell growth were enriched in FCN1+ macrophages of EA compared to those of EB. CONCLUSIONS: FCN1+ macrophage activation associated with airway remodeling processes was upregulated in EA compared to that in EB, which may contribute to airway hyperresponsiveness and airflow obstruction.

Pulmonary IFN-γ Causes Lymphocytic Inflammation and Cough Hypersensitivity by Increasing the Number of IFN-γ-Secreting T Lymphocytes.

PURPOSE: Respiratory viral infection increases the number of lung-resident T lymphocytes, which enhance cough sensitivity by producing interferon-γ (IFN-γ). It is poorly understood why IFN-γ-secreting T lymphocytes persist for a long time when the respiratory viruses have been removed. METHODS: Repeated pulmonary administration of IFN-γ and intraperitoneal injection with different inhibitors were used to study the effects of pulmonary IFN-γ in mice and guinea pigs. RESULTS: IFN-γ administration caused the increasing of IFN-γ-secreting T lymphocytes in both lung and blood, followed by the elevated physiological level of IFN-γ in the lung, the airway inflammation and the airway epithelial damage. IFN-γ administration also enhanced the cough sensitivity of guinea pigs. IFN-γ activated the STAT1 and extracellular signal-regulated kinase (ERK) pathways in lung tissues, released IFN-γ-inducible protein 10 (IP-10), and resulted in F-actin accumulation in lung-resident lymphocytes. The CXC chemokine receptor 3 (CXCR3) inhibitor potently suppressed all the IFN-γ-induced inflammatory changes. The STAT1 inhibitor mitigated IFN-γ-secreting T lymphocytes infiltration by inhibiting T lymphocytes proliferation. F-actin accumulation and the ERK1/2 pathway contributed to pulmonary IFN-γ-induced augmentation of the airway inflammation and increasing of IFN-γ-secreting T lymphocytes in blood. CONCLUSIONS: High physiological levels of IFN-γ in the lung may cause pulmonary lymphocytic inflammation and cough hypersensitivity by increasing the number of IFN-γ-secreting T lymphocytes through the IP-10 and CXCR3 pathways.

Fructus mume Protects Against Cigarette Smoke Induced Chronic Cough Guinea Pig.

Fructus mume was recorded in the Chinese Pharmacopoeia and traditional Chinese medical books for chronic cough, but the effect and related constituents are still unknown. Thus, we investigated the protect effects and the relevant constituents of F. mume in a guinea pig model with chronic cough induced by cigarette smoke (CS). The organic acids and polysaccharides in F. mume were detected by high performance liquid chromatography, gel permeation chromatography, and gas chromatography-mass spectrometry. The guinea pigs were orally administrated with vehicle or the water extract of Fructus mume (FW) during the 14 days of CS exposure. Citric acid induced coughs were automatically measured by Buxco system. The differential cells in bronchoalveolar lavage fluid (BALF) and histopathological changes in lung tissue were assessed by hematoxylin and eosin staining. The tumor necrosis factor alpha (TNF-α) and interleukin-8 (IL-8) levels in lung tissue were detected via enzyme-linked immunosorbent assay. The mucus productions in tracheas were determined with Alcian blue-periodic acid Schiff staining. The results suggested relatively high concentration of citric acid, chlorogenic acid, and neochlorogenic acid in F. mume, and high proportion of galactose and glucose and lower molecular weight of polysaccharides. Administration of FW significantly reduced the cough frequency, decreased inflammatory cells in BALF and lung tissue, and attenuated the thickening of airway epithelium and submucosa compared with CS-exposure group. Moreover, the overproduction of TNF-α and IL-8 in lung tissues, and mucus in central airways of CS-induced guinea pigs was markedly inhibited by FW. The extract could also protect against CS exposure-induced chronic cough in guinea pigs by reducing coughs, airways inflammation, and mucus overproduction.