Ezrin Contributes to the Damage of Airway Epithelial Barrier Related to Diabetes Mellitus.

Background: Diabetes mellitus predisposes individuals to respiratory infections. The airway epithelial barrier provides defense against inhaled antigens and pathogens. Ezrin, is a component of the membrane-cytoskeleton that maintains the cellular morphology, intercellular adhesion, and barrier function of epithelial cells. This study aimed to explore the role of ezrin in airway epithelial barrier damage and correlate its expression and activation with diabetes mellitus. Methods: This study was performed in a murine model of diabetes mellitus and with human bronchial epithelial BEAS-2B cells using real-time PCR, Western blotting, immunohistochemical and immunofluorescence staining. Ezrin was knocked down in BEAS-2B cells using siRNA. Ezrin phosphorylation levels were measured to determine activation status. The integrity of the airway epithelial barrier was assessed in vivo by characterizing morphological structure, and in vitro in BEAS-2B cells by measuring tight junction protein expression, transepithelial electrical resistance (TER) and permeability. Results: We demonstrated that ezrin expression levels were lower in the lung tissue and airway epithelium of diabetic mice than those in control mice. The morphological structure of the airway epithelium was altered in diabetic mice. High glucose levels downregulated the expression and distribution of ezrin and connexin 43, reduced the expression of tight junction proteins, and altered the epithelial barrier characteristics of BEAS-2B cells. Ezrin knockdown had effects similar to those of high glucose levels. Moreover, a specific inhibitor of ezrin Thr567 phosphorylation (NSC305787) inhibited epithelial barrier formation. Conclusion: These results demonstrate that ezrin expression and activation are associated with airway epithelial damage in diabetes mellitus. These findings provide new insights into the molecular pathogenesis of pulmonary infections in diabetes mellitus and may lead to novel therapeutic interventions for airway epithelial barrier damage.

As2 O3 combined with leflunomide prolongs heart xenograft survival via suppressing the response of Th1, Th2, and B cells in a rat model.

Xenotransplantation remits the severe shortage of human organs and tissues for transplantation, which is a problem that severely limits the application of transplantation to the treatment of human disease. However, severe immune rejection significantly limits the efficacy of xenotransplantation. In this study, we systematically investigated the immunosuppressive effect and mechanism of action of As2 O3 and leflunomide using a hamster-to-rat heart xenotransplantation model. We initially examined heart xenograft survival following As2 O3 and leflunomide treatment alone or combined treatment. We found that treatment with As2 O3 combined with leflunomide can significantly prolong the survival of heart xenograft by inhibiting Th1 and Th2 differentiation and reducing the production of IgG and IgM. Interestingly, As2 O3 and leflunomide showed low toxicity to the organs of the recipient. Taken together, these observations indicate that treatment with As2 O3 combined with leflunomide may be a promising immunosuppressive schedule for xenotransplantation.

[Effects of tumor necrosis factor-α converting enzyme on mucous hypersecretion in inflammatory airway].

OBJECTIVE: To investigate the effect of tumor necrosis factor-α converting enzyme (TACE) on mucous hypersecretion in inflammatory airway. METHODS: Mucous hypersecretion model of human lung adenocarcinoma cells A549 was induced by human neutrophil elastase (HNE), and TNF-α converting enzyme inhibitor-1 (TAPI-1), an inhibitor of TACE, was chosen for the inference study. The expression of MUC5AC and TACE was examined. Th e cells were divided into 5 groups: a negative control group, HNE1 (15 nmol/L) group, HNE2 (25 nmol/L) group, HNE3 (50 nmol/L) group and TAPI-1 group. RT-PCR was used to examine MUC5AC and TACE mRNA expression. The protein expression of TACE and MUC5AC was examined by Western blot and ELISA, respectively. RESULTS: HNE induced the TACE and MUC5AC mRNA and protein expression in a dose-dependent manner. Compared with the control group, the increases were all significantly increased in the three dosages of HNE group (P< 0.01). The HNE-induced TACE and MUC5AC mRNA and protein expression were dramatically attenuated in the presence of TAPI-1, an inhibitor of TACE (P< 0.01). CONCLUSION: TACE participated cell signalling pathway of airway mucous hypersecretion, and could down regulation the level of inflammation airway mucous hypersecretion.

[Relation between serum myostatin with BMI and PaO2/PaCO2 in patients with chronic obstructive pulmonary disease].

OBJECTIVE: To determine the relation between serum myostatin with body mass index (BMI) and PaO2/PaCO2 in men with chronic obstructive pulmonary disease (COPD). METHODS: A cohort of outpatients with stable COPD was evaluated. We evaluated the myostatin, PaO2/PaCO2 and BMI, and the patients were stratified by BMI. The plasma level of myostatin and PaO2/PaCO2 was measured by high sensitivity ELISA or blood gas analysis. RESULTS: PaCO2 and myostatin increased significantly compared with those in the control group (P<0.05), but PaO2 decreased significantly. There was positive correlation between myostatin and PaCO2 (P<0.05), and negative correlation between myostatin and BMI/FEV1/pred value/PaO2 (P<0.05). CONCLUSION: Patients with higher myostatin levels had a lower BMI, lower PaO2 and higher PaCO2, with poor pathogenetic condition and prognosis. Myostatin may be a potential treatment target in patients with chronic obstructive pulmonary disease.

Decreased expression of LATS1 is correlated with the progression and prognosis of glioma.

BACKGROUND: LATS1 is a tumor suppressor genes implicated in the pathogenesis of certain types of tumors, but its role is not known in human glioma. METHODS: Using real-time PCR and immunohistochemistry, we detected the mRNA and protein expression of LATS1 in glioma. The effect of LATS1 on cell growth and invasion were investigated. RESULTS: We found that mRNA and protein of LATS1 expression is significantly downregulated in glioma compared with normal control brain tissues. Furthermore, reduced LATS1 expression was markedly negatively correlated with WHO grade and KPS (p<0.001 and p<0.001) in glioma patients. Patients with lower LATS1 expression had a significantly shorter overall survival time than did patients with higher LATS1 expression. Multivariate analysis suggested that the level of LATS1 expression was an independent prognostic indicator (p<0.001) for the survival of patients with glioma. Forced expression of LATS1 in glioma U251 cells not only significantly suppressed cell growth, migration and invasion, but retarded cell cycle progression from G2/M to G1 in vitro. Finally, we found that overexpressed LATS1 markedly inhibited the expression level of cell cycle factor CCNA1. CONCLUSION: These results indicate that LATS1 is an important candidate tumor suppressor and its downregulated expression may contribute to glioma progression.

Theaflavins extracted from black tea inhibit airway mucous hypersecretion induced by cigarette smoke in rats.

Theaflavins isolated from black tea have been used in studies on the prevention of tumor growth. The aim of this study was to investigate whether treatment with theaflavins influences the mucus hypersecretion induced by cigarette smoke in the lungs of experimental rats. Firstly, cigarette smoke was aerosolized using a machine designed for inhalation by rats. The rats were divided into the negative control group, the cigarette smoke inhalation group, the theaflavins (TFs) treatment group, and the TFs +cigarette smoke inhalation group. The animals were sacrificed on day 60 of the experiment. Secondly, the rats were treated with theaflavins at different doses via a gastric tube and sacrificed on day 30. The changes in the levels of mucin 5AC (MUC5AC) and epidermal growth factor receptor (EGFR) in the airway were evaluated. Cigarette smoke induced a significant increase in the levels of MUC5AC and EGFR in all groups. These increases could be reversed by intragastric administration of theaflavins. The effect was more pronounced with the duration of treatment and coincided with a decrease in the expression of both targets. The rats showed various degrees of reduction in the expression of these parameters, which correlated with the theaflavin dose. TFs could inhibit the activation of EGFR, decrease the level of MUC5AC, and relieve airway mucous hypersecretion via the EGFR signaling pathway. These effects correlated directly with the duration of action and the dosage. In the future, oral theaflavins might be valuable in the treatment of chronic airway inflammation.

[Effects of theaflavins on the signal transduction pathway of epidermal growth factor receptor in airway mucous hypersecretion].

OBJECTIVE: To investigate the effects of theaflavins (TFs) on airway mucous hypersecretion and on the signal transduction pathway of epidermal growth factor receptor (EGFR). METHODS: The cell model of mucous hypersecretion was made by human lung A549 cell stimulated by human neutrophil elastase (HNE), and treated with TFs and AG1478, a blocking agent of EGFR. The expression of mucin (MUC) 5AC, EGFR, P-EGFR, phosphorylation extracellular signal regulated kinase 1/2 (P-ERK1/2), P-p38, phosphorylation c-Jun N-terminal kinase (P-JNK) were detected. The cell activity after TFs treatment was assessed by methyl thiazolyl tetrazolium method. The cells were divided into 5 groups: a negative control group, an HNE treatment group, a TFs pre-treatment group, an AG1478 pre-treatment group and a TFs + AG1478 group. The changes of MUC5AC mRNA and EGFR mRNA were examined by the use of reverse transcriptase-polymerase chain reaction (RT-PCR). The protein expression changes of EGFR, P-EGFR, P-ERK1/2, P-p38 and P-JNK were measured by Western blot. The protein expression changes of MUC5AC were detected by enzyme-linked immunosorbent assay, while the protein morphological changes of MUC5AC were observed by immunofluorescence and confocal laser technology. The data were analyzed with SPSS 12.0 software. Differences between groups were assessed for significance by t test. RESULTS: The expression levels of MUC5AC mRNA and its protein in the HNE group were (0.99 +/- 0.03) and (169 +/- 6) microg/mg, and those of EGFR were (0.98 +/- 0.02) and (0.89 +/- 0.03), both of them increased significantly as compared to those in the control group [(0.53 +/- 0.02), (105 +/- 4) microg/mg and (0.61 +/- 0.11), (0.21 +/- 0.05)]. The protein expressions of P-EGFR, P-ERK1/2, P-p38 were increased significantly as compared with the control group. But the increase of P-p38 was not significant as compared to P-ERK1/2. The protein expression of P-JNK did not change markedly. After the cells were pre-treated with TFs and AG1478 respectively, the above measurements were decreased significantly as compared with the HNE group. The decrease was more significant in the TFs + AG1478 group (t = 3.02, P < 0.05). CONCLUSIONS: Theaflavins decreased the level of EGFR and inhibited the activation of EGFR, and attenuated airway mucous hypersecretion via the ERK pathway.