[Effect and mechanism of lipopolysaccharides-induced myeloid-derived suppressor cells on airway inflammation in asthmatic mice].

OBJECTIVE: To explore the effect and mechanism of lipopolysaccharides (LPS)-induced CD11b⁺Gr-1⁺ myeloid-derived suppressor cells (MDSCs) on airway inflammation in asthmatic mice. METHODS: A total of 34 female BALB/c mice were selected. Among them, 4 mice received an intraperitoneal injection of LPS for inducing the accumulation of MDSCs. And the MDSCs were separated with CD11b immunomagnetic beads from spleen extract. Another 30 mice were randomly divided into normal control, asthmatic and cell treatment groups. The mice in the asthmatic and cell treatment groups were sensitized with ovalbumin by a combination of intraperitoneal injection and challenges to establish the murine asthmatic model. At Days 14 and 21 post-sensitization, the mice in cell treatment group received an intravenous injection of LPS-induced MDSCs. At 24 hours after the last allergen challenge, the number of inflammatory cells were counted and morphological identification of leucocytes in bronchoalveolar lavage fluid (BALF) was performed to analyze the degree of airway inflammation in conjunctions with pathological sections. The BALF and serum levels of interleukin-13 were measured by enzyme-linked immunosorbent assay (ELISA). The number of CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Tregs) in peripheral blood was measured by flow cytometry. RESULTS: The total number of cells, the percentage of neutrophils and eosinophils of BALF in the cell treatment group [(17.0 ± 8.3)×104/ml, 11.1% ± 2.0%, 9.8% ± 2.9%] were significantly lower than those in the asthmatic group [(36.0 ± 15.9)×104/ml, 20.8% ± 4.0%, 14.1% ± 4.2%] (P = 0.000, 0.000, 0.011). Compared to the asthmatic group, the BALF and serum levels of IL-13 were significantly lower [(34.7 ± 7.1) vs (105.0 ± 9.0) ng/L, (34.0 ± 4.7) vs (48.1 ± 6.1) ng/L] (both P = 0.000) and the number of CD4⁺CD25⁺Foxp3⁺ regulatory T cells increased in peripheral blood (8.0% ± 1.3% vs 5.1% ± 2.1%, P = 0.002) and airway inflammation was significantly relieved in the cell treatment group. CONCLUSION: LPS-induced MDSCs may improve airway inflammation through up-regulating Tregs in peripheral blood and suppressing Th2 effector function in asthmatic mice.

[Inhibition of lipopolysaccharide-induced myeloid-derived suppressor cells in the proliferation of spleen T lymphocytes].

OBJECTIVE: To explore the effects of lipopolysaccharide (LPS)-induced myeloid-derived suppressor cells (MDSCs) on the proliferation of spleen T lymphocytes. METHODS: BALB/c mice were randomly divided into two groups: LPS group and normal control group. They were injected intraperitoneally with LPS and normal saline solution respectively. MDSCs were separated with CD11b immunomagnetic beads from the spleen extract of mice. The morphological characteristics of MDCSs were observed by Wright-Giemsa staining and the characteristic molecules on cell surface identified by flow cytometry. And the effects of MDSCs on the in vitro proliferation of T cells were determined by methyl-thiazolyl-tetrazolium bromide (MTT). RESULTS: The proportion of MDSCs in the spleen of the LPS group was much more than that of the normal control group (27.4% ± 6.6% vs 5.1% ± 3.8%; t = 5.06, P = 0.007). CD11b(+)Gr-1(+)MDSCs could be separated by CD11b immunomagnetic beads from the spleen of mice injected with LPS at a high purity of 84.0% ± 4.2%. MTT method showed that the proliferation of T cells decreased significantly after a co-cultivation with CD11b(+)MDSCs versus the control group. And it was positively correlated with the number of MDSCs (F = 46.26, P = 0.000). CONCLUSIONS: A high purity of LPS-induced myeloid-derived suppressor cells may be separated with CD11b immunomagnetic beads. And it has dose-dependent inhibitory effects on the proliferation of the spleen T lymphocytes.

[Pathogenic mechanism of CD8(+)CD28(-)T cell and the effect of dexamethasone in asthmatic mouse].

OBJECTIVE: To explore whether or not CD8(+)CD28(-)T cell play a pathogenic role in asthma and detect the effects of dexamethasone (DXM). METHODS: A total of 30 mice were randomly divided into 3 groups: asthmatic group, DXM group and control group (n = 10 each). The asthmatic and DXM groups were sensitized twice and inhaled ovalbumin. The DXM Group received an intraperitoneal injection of DXM 1mg/kg before inhaling ovalbumin. After successful modeling, 3 mice were selected randomly from each group to measure the airway responsiveness. Also a bronchoalveolar lavage cytological study was performed and lung tissue sections were prepared for histopathologic examination to evaluate the airway inflammation. The content of IgE in bronchoalveolar lavage fluid (BALF) was detected with a murine IgE ELISA kit. And the fractions of CD8(+)CD28(-)T cell of peripheral blood and BALF were tested by flow cytometry to analyze the correlation between IgE, eosinophils (EOS) of BALF and CD8(+)CD28(-)T cell of blood. RESULTS: The airway hyperresponsiveness in asthmatic and DXM groups were significantly higher than that in the control group. The number of total cells and EOS of BALF in the asthmatic group [(5.56 ± 4.06) × 10(2)/L; (3.29 ± 2.23) × 10(2)/L] were significantly higher than that in control group [(0.91 ± 0.65) × 10(2)/L, P = 0.003; (0.43 ± 0.37) × 10(2)/L, P = 0.001] and DXM group [(2.59 ± 1.69) × 10(2)/L, P = 0.044; (1.11 ± 0.73) × 10(2)/L, P = 0.008]; while the DXM group was insignificantly higher than the control group (P = 0.234, P = 0.363). There were significant differences in the contents of IgE of BALF for the asthmatic, DXM and control groups [(23.85 ± 5.97) g/L, (13.15 ± 2.22) g/L, (6.54 ± 1.03) g/L, F = 38.558, P = 0.000]. The percentages of CD8(+)CD28(-)T cell in peripheral blood in asthmatic and DXM groups [(18.68 ± 4.12)% and (13.43 ± 2.91)%] were significantly higher than those in control mice [(8.43 ± 4.60)%, both P < 0.05]. The percentages of CD8(+)CD28(-)T cell of BALF in asthmatic group and DXM group [(1.25 ± 0.40)% and (0.66 ± 0.49)%] were also significantly higher than those in control mice [(0.21 ± 0.19)%, both P < 0.05]. The percentages of CD8(+)CD28(-)T cell of blood and BALF in the DXM mice were significantly lower than those in asthmatic group. The correlations between IgE (r = 0.864, P = 0.012), EOS (r = 0.804, P = 0.029) and CD8(+)CD28(-)T cell were significant. CONCLUSION: The fraction of CD8(+)CD28(-)T cell is closely correlated with the inflammation of asthmatic airway. The airway hyperresponsiveness and inflammation in asthmatic mice may be relieved by DXM through its effect of inhibiting the expression of CD8(+)CD28(-) T cell.

Monocyte chemotactic protein-inducing protein 1 negatively regulating asthmatic airway inflammation and mucus hypersecretion involving γ-aminobutyric acid type A receptor signaling pathway in vivo and in vitro.

BACKGROUND: Mounting evidence, consistent with our previous study, showed that γ-aminobutyric acid type A receptor (GABAAR) played an indispensable role in airway inflammation and mucus hypersecretion in asthma. Monocyte chemotactic protein-inducing protein 1 (MCPIP1) was a key negative regulator of inflammation. Recent studies showed that inflammation was largely suppressed by enhanced MCPIP1 expression in many inflammatory diseases. However, the role and potential mechanism of MCPIP1 in airway inflammation and mucus hypersecretion in asthma were still not well studied. This study was to explore the role of MCPIP1 in asthmatic airway inflammation and mucus hypersecretion in both mice and BEAS-2B cells, and its potential mechanism. METHODS: In vivo, mice were sensitized and challenged by ovalbumin (OVA) to induce asthma. Airway inflammation and mucus secretion were analyzed. In vitro, BEAS-2B cells were chosen. Interleukin (IL)-13 was used to stimulate inflammation and mucus hypersecretion in cells. MCPIP1 Lentiviral vector (LA-MCPIP1) and plasmid-MCPIP1 were used to up-regulate MCPIP1 in lung and cells, respectively. MCP-1, thymic stromal lymphopoietin (TSLP), mucin 5AC (MUC5AC), MCPIP1, and GABAARß2 expressions were measured in both lung and BEAS-2B cells. Immunofluorescence staining was performed to observe the expression of GABAARß2 in cells. RESULTS: MCPIP1 was up-regulated by LA-MCPIP1 (P < 0.001) and plasmid-MCPIP1 (P < 0.001) in lung and cells, respectively. OVA-induced airway inflammation and mucus hypersecretion, OVA-enhanced MCP-1, TSLP, MUC5AC, and GABAARß2 expressions, and OVA-reduced MCPIP1 were significantly blunted by LA-MCPIP1 in mice (all P < 0.001). IL-13-enhanced MCP-1, TSLP, MUC5AC, and GABAARß2 expressions, and IL-13-reduced MCPIP1 were markedly abrogated by plasmid-MCPIP1 in BEAS-2B cells (all P < 0.001). CONCLUSION: The results of this study suggested that OVA and IL-13-induced airway inflammation and mucus hypersecretion were negatively regulated by MCPIP1 in both lung and BEAS-2B cells, involving GABAAR signaling pathway.

Extent of Lung Involvement and Serum Cryptococcal Antigen Test in Non-Human Immunodeficiency Virus Adult Patients with Pulmonary Cryptococcosis.

BACKGROUND: Serum cryptococcal antigen (CrAg) test is the most used noninvasive method to detect cryptococcal infection. However, false-negative CrAg test is not uncommon in clinical practice. Then, the aim of this study was to investigate the factors associated with false-negative CrAg test among non-human immunodeficiency virus (HIV) adult patients with pulmonary cryptococcosis and its clinical features. METHODS: One hundred and fourteen non-HIV adult patients with pulmonary cryptococcosis, proven by biopsy, were retrospectively reviewed. Finally, 85 patients were enrolled; 56 were CrAg positive (CrAg+ group) and 29 were negative (CrAg- group). It was a cross-sectional study. Then, baseline characteristics, underlying diseases, clinical symptoms, laboratory findings, and chest radiological findings were reviewed and analyzed. Chi-square test was used to analyze categorical variable. Odds ratio (OR) was used to measure correlation. Student's t- test was obtained to analyze continuous variable. RESULTS: No difference in baseline characteristics, underlying diseases, clinical symptoms, and laboratory findings were found between two groups (P > 0.05 in all). Nevertheless, diffuse extent lesion was 82.1% in CrAg+ group and 10.3% in CrAg- group (χ2 = 40.34, P < 0.001; OR = 39.87). CONCLUSIONS: Among patients with limited pulmonary involvement, a negative serum CrAg does not preclude the diagnosis of pulmonary cryptococcosis. However, among patients with extensive pulmonary involvement, serum CrAg is a useful diagnostic tool for pulmonary cryptococcosis. Furthermore, we also noticed that the untypical and mild presentations with extensive pulmonary lesion might be the features of pulmonary cryptococcosis, which needs further investigation.

[Expression of interleukin-17A in asthmatic mice and its significance].

OBJECTIVE: To study the serum level of interleukin-17A (IL-17A) and its expressions in the lung, spleen and thymus in asthmatic mice. METHODS: In 14 normal BALB/c female mice and 14 asthmatic mice, the changes in the airway pathology and the cell proportion in the bronchoalveolar lavage fluid (BALF) were observed. The serum level of IL-17A and IL-17A expressions in the tissue homogenates of the lung, spleen and thymus of the mice were detected by sandwich enzyme-linked immunosorbent assay (ELISA). RESULTS: The airway inflammation in the asthmatic mice was characterized mainly by eosinophil and neutrophil infiltration, which was not observed in the normal control group. Serum IL-17A levels and IL-17A expressions in the lung, spleen and thymus of the asthmatic mice were significantly higher than those in the normal control group (P<0.01). In the asthmatic mice, IL-17A expression in the lung tissues was positively correlated with the percentages of neutrophils (r=0.693, P=0.040) and eosinophils (r=0.733, P=0.030) in the BALF. CONCLUSION: IL-17A is highly expressed in the serum, lung, spleen and thymus of asthmatic mice. IL-17A may be one of the major cytokines involved in exacerbation of bronchial asthma, and is probably associated with the recruitment of neutrophils and eosinophils into the airways.