Phagocyte extracellular traps formation contributes to host defense against Clostridium perfringens infection.

Clostridium perfringens (C. perfringens) is an important Gram-positive anaerobic spore-forming pathogen that provokes life-threatening gas gangrene and acute enterotoxaemia, although it colonizes as a component of the symbiotic bacteria in humans and animals. However, the mechanisms by which C. perfringens is cleared from the host remains poorly understood, thereby impeding the development of novel strategies for control this infection. Here, we uncover a beneficial effect of extracellular traps (ETs) formation on bacterial killing and clearance by phagocytes. C. perfringens strain ATCC13124, and wild-type isolates CP1 and CP3 markedly trigger ETs formation in macrophages and neutrophils. As expected, visualization of DNA decorated with histone, myeloperoxidase (MPO) and neutrophils elastase (NE) in C. perfringens-triggered classical ETs structures. Notably, the bacteria-induced ETs formation is an ERK1/2-, P38 MAPK-, store-operated calcium entry (SOCE)-, NADPH oxidase-, histone-, NE-, and MPO-dependent process, and is independent of LDH activity. Meanwhile, the defect of bactericidal activity is mediated by impairing ETs formation in phagocytes. Moreover, In vivo studies indicated that degradation of ETs by DNase I administration leads to a defect in the protection against experimental gas gangrene, with higher mortality rates, exacerbated tissue damage, and more bacterial colonization. Together, these results suggest that phagocyte ETs formation is essential for the host defense against C. perfringens infection.

[Simultaneous determination and analysis of amino acids and nucleosides in Dendrobium by UHPLC-QTRAP-MS/MS].

By using multivariate statistical analysis to evaluate essential quality, and provide scientific basis for their comprehensive utilization, we established an UHPLC-QTRAP-MS/MS method for the fast, precise, efficient determination of 21 kinds of amino acids and 10 kinds of nucleosides in different species of Dendrobium. The analysis was performed on a Waters XBridge Amide column(2.1 mm×100 mm,3.5 µm) with elution by mobile phase of 0.2% formic acid in water-0.2% formic acid in acetonitrile at a flow rate of 0.2 mL·min~(-1) with the column temperature at 30 ℃. The target compounds were analyzed by the positive ion multiple reaction monitoring(MRM) mode. The comprehensive evaluation of different species of Dendrobium was carried out by PCA and TOPSIS analysis. All 21 kinds of amino acids and 10 nucleosides showed good linearity among certain concentration range(r>0.999), the RSDs of the stability, precision, and repeatability tests were less than 3.0%. The recovery rate was in the range from 93.31% to 107.5%, and RSD was in the range of 1.1%-3.7%. The comprehensive evaluation index obtained with PCA showed that D. huoshanense was significantly higher than others regarding amino acids and D. officinale has higher nucleosides than other species. The biggest C_i difference of TOPSIS was 68.7%, and comprehensive evaluation showed that D. huoshanense produced the highest comprehensive quality. The method is precise, fast and efficient and can provide reliable basis for further researches and intrinsic quality control of Dendrobium.

Untargeted metabonomics and TLR4/ NF-κB signaling pathway analysis reveals potential mechanism of action of Dendrobium huoshanense polysaccharide in nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is marked by hepatic steatosis accompanied by an inflammatory response. At present, there are no approved therapeutic agents for NAFLD. Dendrobium Huoshanense polysaccharide (DHP), an active ingredient extracted from the stems of Dendrobium Huoshanense, and exerts a protective effect against liver injury. However, the therapeutic effects and mechanisms of action DHP against NAFLD remain unclear. DHP was extracted, characterized, and administered to mice in which NAFLD had been induced with a high-fat and high-fructose drinking (HFHF) diet. Our results showed that DHP used in this research exhibits the characteristic polysaccharide peak with a molecular weight of 179.935 kDa and is composed primarily of Man and Glc in a molar ratio of 68.97:31.03. DHP treatment greatly ameliorated NAFLD by significantly reducing lipid accumulation and the levels of liver function markers in HFHF-induced NAFLD mice, as evidenced by decreased serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol (TC) and total triglyceride (TG). Furthermore, DHP administration reduced hepatic steatosis, as shown by H&E and Oil red O staining. DHP also inhibited the Toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) signaling pathway expression, thereby reducing levels of hepatic proinflammatory cytokines. Besides, untargeted metabolomics further indicated that 49 metabolites were affected by DHP. These metabolites are strongly associated the metabolism of glycine, serine, threonine, nicotinate and nicotinamide, and arachidonic acid. In conclusion, DHP has a therapeutic effect against NAFLD, whose underlying mechanism may involve the modulation of TLR4/NF-κB, reduction of inflammation, and regulation of the metabolism of glycine, serine, threonine, nicotinate and nicotinamide metabolism, and arachidonic acid metabolism.

The pseudokinase MLKL contributes to host defense against Streptococcus pluranimalium infection by mediating NLRP3 inflammasome activation and extracellular trap formation.

Host innate immunity plays a pivotal role in the early detection and neutralization of invading pathogens. Here, we show that pseudokinase mixed lineage kinase-like protein (MLKL) is required for host defence against Streptococcus pluranimalium infection by enhancing NLRP3 inflammasome activation and extracellular trap formation. Notably, Mlkl deficiency leads to increased mortality, increased bacterial colonization, severe destruction of organ architecture, and elevated inflammatory cell infiltration in murine models of S. pluranimalium pulmonary and systemic infection. In vivo and in vitro data provided evidence that potassium efflux-dependent NLRP3 inflammasome signalling downstream of active MLKL confers host protection against S. pluranimalium infection and initiates bacterial killing and clearance. Moreover, Mlkl deficiency results in defects in extracellular trap-mediated bactericidal activity. In summary, this study revealed that MLKL mediates the host defence response to S. pluranimalium, and suggests that MLKL is a potential drug target for preventing and controlling pathogen infection.

Erratum: Mixed lineage kinase-like protein protects against Clostridium perfringens infection by enhancing NLRP3 inflammasome-extracellular traps axis.

[This corrects the article DOI: 10.1016/j.isci.2022.105121.].

Mixed lineage kinase-like protein protects against Clostridium perfringens infection by enhancing NLRP3 inflammasome-extracellular traps axis.

Despite intense research in understanding Clostridium perfringens (C. perfringens) pathogenesis, the mechanisms by which it is cleared from the host are largely unclarified. In C. perfringens gas gangrene and enterocolitis model, Mlkl -/- mice, lacking mixed lineage kinase-like protein (MLKL), are more susceptible to C. perfringens infection. Mlkl deficiency results in a defect in inflammasome activation, and IL-18 and IL-1ß releases. Exogenous administration of recombinant IL-18 is able to rescue the susceptibility of Mlkl -/- mice. Notably, K+ efflux-dependent NLRP3 inflammasome signaling downstream of active MLKL promotes bacterial killing and clearance. Interestingly, the defect of bactericidal activity is also mediated by decreased classical extracellular trap formation in the absence of Mlkl. Our results demonstrate that MLKL mediates extracellular trap formation in a NLRP3 inflammasome-dependent manner. These findings highlight the requirement of MLKL for host defense against C. perfringens infection through enhancing NLRP3 inflammasome-extracellular traps axis.

[Clinical classification of 288 cases of bronchial tuberculosis based on an expert consensus].

OBJECTIVE: To study the clinical application and significance of the recently published expert consensus on endobronchial tuberculosis (EBTB). METHODS: A retrospective analysis of 288 cases of EBTB hospitalized in Tianjin Haihe Hospital from May 2005 to April 2010 was carried out. The classification and typing of the disease were based on a consensus report recently published by Chinese Journal of Tuberculosis and Respiratory Diseases. Chi-square test was performed to analyze the differences between groups. RESULTS: Of the 288 cases of EBTB, 47.9% (138/288) was classified as Type I (Inflammatory infiltrative), 33.3% (96/288) as Type II (ulcerous necrotic), 5.2% (15/288) as Type III (granulomatous hyperplastic), 7.3% (21/288) as Type IV (scar stricture) and 0.4% (1/288) as Type V (Bronchomalacia), respectively. There were 17 cases (5.9%) classified as a mixed type with a combination of Type IV or Type V disease with 1 or more of the other types. 37.5% (108/288) of the patients were young females, while young and middle-aged patients with type I and type II diseases accounted for 74.7% (215/288) of the cases, much more than old aged patients (6.6%, 19/288). 97.2% (n=280) of the cases suffered from secondary pulmonary tuberculosis. In 107 cases, the disease was located in the left, 162 cases in the right, while in 109 cases the right upper lobe bronchus was involved, and right main bronchus in 36 cases, 3 cases and 58 cases in left upper lobe with and without lingular segment, 10 cases in lingular segment only. Chest CT showed that local mucosal thickening of the trachea or bronchus was evident in 40.3% (116/288); toothed or spike protuberance in 30.9% (89/288), bronchial obstruction in 11.1% (32/288), and bronchial stenosis in 87.9% (253/288). The negative rate of sputum in the first month after interventional therapy was 60.2% (56/93), significantly higher than that in non-interventional therapy group (23.1%, 18/78). CONCLUSION: The new consensus report on EBTB was clinically useful for classification and typing of the disease, and for the selection of treatment modalities.

Long non-coding RNA MALAT1 exacerbates acute respiratory distress syndrome by upregulating ICAM-1 expression via microRNA-150-5p downregulation.

Acute respiratory distress syndrome (ARDS) is a severe form of acute lung injury in which severe inflammatory responses induce cell apoptosis, necrosis, and fibrosis. This study investigated the role of lung adenocarcinoma transcript 1 (MALAT1) in ARDS and the underlying mechanism involved. The expression of MALAT1, microRNA-150-5p (miR-150-5p), and intercellular adhesion molecule-1 (ICAM-1) was determined in ARDS patients and lipopolysaccharide (LPS)-treated human pulmonary microvascular endothelial cells (HPMECs). Next, the interactions among MALAT1, miR-150-5p, and ICAM-1 were explored. Gain- or loss-of-function experiments in HPMECs were employed to determine cell apoptosis and inflammation. Furthermore, a mouse xenograft model of ARDS was established in order to verify the function of MALAT1 in vivo. MALAT1 and ICAM-1 were upregulated, while miR-150-5p was downregulated in both ARDS patients and LPS-treated HPMECs. MALAT1 upregulated ICAM-1 expression by competitively binding to miR-150-5p. MALAT1 silencing or miR-150-5p overexpression was shown to suppress HPMEC apoptosis, decrease the expressions of pro-inflammatory cytokines (IL-6, IL-1ß and TNF-α) and E-selectin in HPMECs, as well as alleviated lung injury in nude mice. These findings demonstrated that MALAT1 silencing can potentially suppress HPMEC apoptosis and alleviate lung injury in ARDS via miR-150-5p-targeted ICAM-1, suggestive of a novel therapeutic target for ARDS.

microRNA-328 in exosomes derived from M2 macrophages exerts a promotive effect on the progression of pulmonary fibrosis via FAM13A in a rat model.

Currently, exosome-enclosed microRNAs (miRs) in exhaled breath have potential for biomarker discovery in patients with pulmonary diseases. This study was performed to investigate the roles of M2 macrophage-derived exosomes expressing miR-328 in pulmonary fibrosis (PF). Microarray-based analysis was used to screen differentially expressed genes (DEGs) and regulatory miRs in PF. The miR-target relationship between FAM13A and miR-328 was confirmed. The expression of FAM13A and miR-328 was measured in PF rats, and gain- and loss-of-function assays were conducted to determine the regulatory effects of FAM13A and miR-328 on PF. In addition, exosomes derived from M2 macrophages were isolated and then cocultured with pulmonary interstitial fibroblasts to identify the role of these exosomes in PF. Furthermore, the effects of M2 macrophage-derived exosomes overexpressing miR-328 on pulmonary fibroblast proliferation and the progression of PF were assessed in vivo. miR-328 might perform a vital function in PF by regulating FAM13A. FAM13A expression was downregulated while miR-328 expression was upregulated in rats with PF, and a miR-target relationship between miR-328 and FAM13A was observed. Additionally, miR-328 overexpression and FAM13A silencing each were suggested to promote pulmonary interstitial fibroblast proliferation and the expression of Collagen 1A, Collagen 3A and α-SMA. Then, in vitro experiments demonstrated that M2 macrophage-derived exosomes overexpressing miR-328 contributed to enhanced pulmonary interstitial fibroblast proliferation and promoted PF. Furthermore, in vivo experiments confirmed the promotive effects of M2 macrophage-derived exosomes overexpressing miR-328 on the progression of PF. Collectively, the results showed that M2 macrophage-derived exosomes overexpressing miR-328 aggravate PF through the regulation of FAM13A.

Regulatory T cell activity in immunosuppresive mice model of pseudomonas aeruginosa pneumonia.

Pseudomonas aeruginosa (PA) pneumonia is a refractory, even lethal complication in immunosuppressive individuals and immune disturbances may promote the pathological process. We aimed to investigate the regulatory T (Treg) cell activity in an immunosuppressive mice model of PA pneumonia by estimating levels of main transcription factor and the main effector of Treg cells, i.e., Forkhead box protein 3 (FOXP3) and interleukine-10 (IL-10). Seventy-two BALB/c mice were divided into four groups randomly: control (A), PA pneumonia (B), immunosuppression (C) and immunosuppression with PA pneumonia (D). Mice were sacrificed at 4, 8 and 24 h after establishing experimental models. The pathological changes of lung tissue were graded, and the FOXP3 mRNA and serum IL-10 levels were detected. Histological analysis of lung tissues showed there were no significantly pathological changes in groups A and C, but significantly pathological changes were found in groups B and D, especially in group D at 8 h (P<0.05). The expression levels of FOXP3 mRNA in groups A and C showed no significant changes at the three time points, which were significantly lower than those in groups B and D (P<0.05). FOXP3 mRNA levels were lowest at 4 h, and there was significant difference between groups B and D (P<0.05). The serum levels of IL-10 in groups A and C were almost normal at the three time points, but decreased significantly in groups B and D (P<0.05). The serum levels of IL-10 decreased to the lowest at 8 h, especially in group D (P<0.05). The results indicate that PA pneumonia in immunosuppressive individuals worsens rapidly, which may be associated with Treg cells function disturbance. And Treg cells may be promising as adjuvant therapeutics for PA pneumonia in immunosuppressive individuals.

[Effects of glucocorticoid on airway mucus secretion in asthma: experiment with asthmatic mouse model].

OBJECTIVE: To study the effects of glucocorticoid on airway mucus secretion in asthma. METHODS: Twenty-four BALB/c mice were randomly divided into 3 equal groups: asthma group [ovalbumin (OVA) and aluminum hydroxide were injected intraperitoneally on day 0 and day 14 so as to establish mouse asthma model and aerosol inhalation of OVA PBS was conducted for 30 min on the days 21, 22, and 24], asthma + dexamethasone group (OVA and aluminum hydroxide were injected intraperitoneally on days 0 and 14, aerosol inhalation of OVA PBS was conducted for 30 min on the days 21, 22, and 24, and dexamethasone was injected intraperitoneally 1 hour before the aerosol inhalation), and control group (aerosol inhalation of PBS was conducted instead). Twenty-fours hours after the last exposure the mice were anesthetized deeply and their left lungs were excised to collect the bronchoalveolar lavage fluid (BALF) to calculate the numbers of total cells and eosinophils, then Alcian blue/periodic acid-Schiff staining and immunohistochemistry of the air passage were conducted to measure the expression levels of MUC5AC mRNA and protein and interleukin-4 (IL-4) mRNA. RESULTS: The numbers of total cells in the BALF of the asthma group were (12.50 +/- 0.14) x 10(9)/L and (1.12 +/- 0.10) x 10(9)/L respectively, both significantly higher than those of the control group, (6.49 +/- 0.05) x 10(9)/L and (0.05 +/- 0.02) x 10(9)/L respectively (both P < 0.01), and were significantly higher than those of the asthma + dexamethasone group, (6.68 +/- 0.03) x 10(9)/L and (0.06 +/- 0.01) x 10(9)/L respectively too (both P < 0.01). The levels of MUC5AC mRNA, MUC5AC protein, and IL-4 mRNA of the asthma group were 0.5341 +/- 0.303, 0.1906 +/- 0.0008, and 0.6265 +/- 0.0932 respectively, all significantly higher than those of the control group (0.1994 +/- 0.0128, 0.1194 +/- 0.0007, and 0.2389 +/- 0.0289 respectively, all P < 0.01), and those of the asthma + dexamethasone group (0.2729 +/- 0.0345, 0.1456 +/- 0.0003, and 0.2424 +/- 0.0260, all P < 0.05). The MUC5AC protein expression and mRNA expression, and IL-4 mRNA expression of the asthma group were 0.1906 +/- 0.0008, 0.5341 +/- 0.0303, and 0.6265 +/- 0.0932 respectively, all significantly higher than those of the control group (0.1194 +/- 0.0007, 0.1994 +/- 0.0128, and 0.2398 +/- 0.0289 respectively, all P < 0.01). The MUC5AC protein expression and mRNA expression, and IL-4 mRNA expression of the asthma + dexamethasone group were 0.1456 +/- 0.0003, 0.2729 +/- 0.0345, and 0.2424 +/- 0.0260 respectively, all significantly lower than those of the asthma group (all P < 0.01). The MUC5AC protein expression and mRNA expression of the asthma + dexamethasone group were still significantly higher than those of the control group (both P < 0.01), however, the IL-4 mRNA expression of the asthma + dexamethasone group was not significantly different from that of the control group (P > 0.05). CONCLUSION: Relieving the inflammation, glucocorticoid may play a role in the treatment of excessive mucus production through down-regulating the expression of MUC5AC and of IL-4.

Levels of serum procalcitonin and C-reactive protein for evaluating pulmonary bacterial infection in patients with lupus erythematosus.

The severity of systemic lupus erythematosus (SLE) patients with pulmonary bacterial infection varies widely. We investigated the significance of procalcitonin (PCT) and C-reactive protein (CRP) in evaluating the severity of pulmonary infection in SLE patients. This retrospective study contained a total of 117 patients (107 women and 10 men) with SLE from January 2010 to June 2011. Serum levels of PCT and CRP were measured by enzyme-linked immunosorbent assay. The severity of pulmonary bacterial infection (PBI) was evaluated using the pneumonia severity index (PSI). SLE patients with PBI, particularly those with bacterial isolates, had significantly higher levels of serum PCT and CRP than those without PBI. Serum PCT and CRP were not associated with SLE disease activity, but positively with the values of PSI in active SLE patients with PBI. Serum levels of PCT and CRP may be additional biomarkers in evaluating the severity of PBI in lupus patients.

Pulmonary embolism, deep vein thrombosis and recurrent bone cysts in a patient with hypereosinophilic syndrome.

Herein we present a case of hypereosinophilic syndrome with a unique clinical presentation. A 32-year-old man was admitted because of fever, hemoptysis and chest pain. The main clinical features include hypereosinophilia, deep vein thrombosis, pulmonary embolism, thrombocytopenia and recurrent bone cysts. The plain film of the left foot revealed dissolvent bone destruction. The histological findings of bone cysts include eosinophilic infiltration and tissue necrosis. According to the case history and literature, it is possible that hypereosinophilia itself may be a risk for thrombogenesis and the bone destruction.

Expression of Fascin-1 on human lung cancer and paracarcinoma tissue and its relation to clinicopathological characteristics in patients with lung cancer.

BACKGROUND: Lung cancer poses a severe threat to human life. Biomarkers of cancers are helpful in the diagnosis and treatment of patients with cancers. Biomarkers of lung cancers are rare, and thus deserve further research. OBJECTIVE: The objective of the present study was to explore the expression of Fascin-1 in human lung cancer and paracarcinoma tissue, its correlation with clinicopathological characteristics in patients with lung cancer, and study the possible relationship between Fascin-1 expression and clinical-biological behavior of lung cancer. METHOD: This study used the MaxVision two-step immunohistochemical detection method to detect Fascin-1 expression in 84 of lung cancer and paracarcinoma tissues. This study set the expression of Fascin-1 in vascular endothelial cells as the positive control, and used phosphate buffered saline (replacing the primary antibodies) as negative control. RESULT: Of all the 84 lung cancer tissues and paracarcinoma tissues, positive expression of the Fascin-1 protein were detected in 78 cases (92.9%) and 27 cases (32.1%), respectively, and the difference was statistically significant (P<0.05). Differences in Fascin-1 expression between different age groups, clinical stages, and lymph node metastases were statistically significant (P<0.05), while differences in Fascin-1 expression between sexes, tumor stages, and pathological types demonstrated no statistical significance (P>0.05). The survival times of the patients with different Fascin-1 protein-positive expressions in lung cancer tissues were statistically significant (P>0.05), while the survival times of the patients with different Fascin-1 protein-positive expressions in paracarcinoma tissues were not statistically significant (P>0.05). CONCLUSION: In lung cancer, Fascin-1 expression was closely related to tumor invasion and metastasis, and the difference in expression of Fascin-1 had a significant effect on the survival time of the lung cancer patients. Therefore, Fascin-1 might be expected to serve as a possible potential biomarker of lung cancer.

Expression of eosinophils be beneficial to early clinical diagnosis of brucellosis.

OBJECTIVE: Investigate the expression and significance of eosinophils in brucellosis. METHODS: Retrospective analysis of clinical data for 151 brucellosis patients (BR group), complete blood count and blood bacterial culture etc.; in addition, 150 general bacterial infection patients (BI group) and 135 persons in healthy physical condition upon testing (NC group) are selected respectively as the control groups to comparatively study expression of white blood cells and eosinophils for brucellosis patients. Adopt t test to compare measurement data. RESULTS: In comparison with BI group, WBC, NE, EO, MO, NE% and EO% in BR group are reduced but LY, LY% and MO% are increased and such difference shows statistical significance (P<0.01). In comparison with NC group, difference of WBC and NE in BR group shows no statistical significance (P>0.05). NE%, EO and EO% are reduced but MO, LY% and MO% are increased and such difference shows statistical significance (P<0.01). LY is increased and the difference shows statistical significance (P<0.05). White blood cell count is normal or is reduced among most of Brucellosis patients, accounting for 90.73% (137/151); the patients whose eosinophils are reduced account for 75.50% (114/151) and those whose eosinophils disappear are about 18.54% (28/151). CONCLUSION: There is an incidence rate of eosinophils decrease or disappearance in Brucellosis and it shows the indication significance in the diagnosis of early disease.

[Effects of interleukin-13 on the gob-5 and MUC5AC expression in lungs of a murine asthmatic model].

OBJECTIVE: To study the influence of interleukin-13 (IL-13) on the gob-5, a member of Ca(2+)-activated Cl(-) channel and mucin gene MUC5AC expression in lungs of a murine asthmatic model, and to investigate their effects on the pathogenesis of asthma. METHODS: Forty-five male BALB/c mice were randomly divided into a control group, an asthmatic group and an IL-13 group. Expression of gob-5 mRNA, MUC5AC mRNA and MUC5AC protein in the lungs were detected by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical assay respectively. RESULTS: No gob-5 mRNA expression in the lung was detected in the control group, while it was positive in the asthmatic group. The gob-5 mRNA in the lung of the IL-13 group and the asthmatic group was 1.246 +/- 0.008 and 1.136 +/- 0.007 respectively (P < 0.01). In the asthmatic group, both MUC5AC mRNA (0.161 +/- 0.011) and protein expression (7 mice positive) increased compared with the control group (0.070 +/- 0.004 and 2 mice positive, respectively) (P < 0.01 and 0.05, respectively). IL-13 increased the expression of MUC5AC mRNA (0.250 +/- 0.014) and protein (13 mice positive) in the lung of the asthmatic group, and there was a significant difference between the IL-13 group and either the control group (0.070 +/- 0.004 and 2 mice positive, respectively) or the asthmatic group (0.161 +/- 0.011 and 7 mice positive, respectively, all P < 0.05). There was a significant association between gob-5 mRNA expression and MUC5AC mRNA expression in both the IL-13 group and the asthmatic group (r = 0.986 and 0.961, respectively, both P < 0.05). CONCLUSION: IL-13 is a critical cytokine in the pathogenesis of asthma, and gob-5 may be one of the important genes in inducing airway mucus overproduction of asthma.