Mycobacterium marinum Infection in Zebrafish and Microglia Imitates the Early Stage of Tuberculous Meningitis.

Mycobacterium tuberculosis (M. tuberculosis) invading and activating microglia causes the most serious subtypes of tuberculosis called tubercular meningitis. However, the developmental process of tubercular meningitis, especially the early phase, is poorly understood due to lacking well-established and well-accepted visible models in vitro and in vivo. Here, consistent with one recent report, we found Mycobacterium marinum (M. marinum) invade the zebrafish brain and subsequently cause granuloma-like structures. We further showed that M. marinum, which shares similar characteristics with M. tuberculosis, can invade microglia and replicate in microglia, which subsequently promote the secretion of pro-inflammatory cytokines such as IL-1ß, IL-6, and TNF-α. M. marinum infection in microglia can also promote autophagy, which conversely limits the replication of M. marinum. Thus, pharmacological activation of autophagy by rapamycin could prevent M. marinum replication. Our study provides in vivo and in vitro models to study underlying pathogenic mechanisms of tubercular meningitis by using M. marinum. Our results also showed that activation of autophagy could be a meaningful way to prevent tubercular meningitis.

[Expression and correlation of Skp2 and p27(kip1) in 92 cases of non-Hodgkin's lymphoma].

OBJECTIVE: To investigate the expression and correlation of Skp2 and p27kipl in non-Hodgkin's lymphoma. METHODS: The expression of Skp2, p27(kip1) and Ki-67 (the proliferation index)were detected in sections of 92 cases of non-Hodgkin's lymphoma (NHL) and 14 cases of reactive lymph nodes by immunohistochemistry and histopathology. The expression of Skp2 and p27(kip1) in 4 NHL cell lines were detected by Western blot. RESULTS: The expression of Skp2 in NHL cases were significantly higher than that in reactive lymph nodes (except the germinal centers), positively correlated with proliferation activity, and an increasing tumor aggressiveness was associated with the increased expression of Skp2. The expression of p27(kip1) protein in NHL cases were significantly lower than that in reactive lymph nodes (except the germinal centers), negatively correlated with proliferation activity, and an increasing tumor aggressiveness was associated with decreased expression of p27(kip1). The statistical analysis indicated that there was no obvious correlation between Skp2 and p27(kip1) expression in NHL tissues. CONCLUSION: The higher expression of Skp2 and lower expression of p27(kip1) in NHL tissues may play a role in the tumorigenesis and development of NHL.

Changes of Src-suppressed C kinase substrate expression in cytokine induced reactive C6 glioma cells.

OBJECTIVE: To investigate effect of tumor necrosis factor-alpha (TNF-alpha) on the Src-suppressed C kinase substrate (SSeCKS) in C6 glioma cells. METHODS: Cultured C6 glioma cells were randomly divided into two groups. In time-dependent group, cells were cultured with TNF-alpha (2 ng/mL) for 0 h, 1 h, 3 h, 6 h, 12 or 24 h, respectively; in dose-dependent group, cells were cultured with TNF-alpha (0 ng/mL, 0.02 ng/mL, 0.2 ng/mL, or 2 ng/mL) for 6 h. The expression of SSeCKS was detected by Realtime PCR and Western blot analysis, and immunocytochemistry was used to investigate SSeCKS's subcellular localization. RESULTS: TNF-alpha induced rapid phosphorylations of protein kinase C (PKC) substrates in C6 glioma cells, and upregulated SSeCKS expression in a time and concentration dependent manner. Immunocytochemistry suggested that SSeCKS was localized in the cyroplasm and the leading end of podosomal extensions in control groups, while TNF-alpha induced translocation of SSeCKS perinuclear. This effect could be partly reversed by PKC inhibitor Ro-31-8220. CONCLUSION: TNF-alpha activates PKC and upregulates SSeCKS expression in C6 glioma cells. These effects are associated with PKC activity, suggesting that SSeCKS plays a role in response to glia activation in PKC mediated pathway.

[Expression and relationship of p27(kip1) and its related molecules Jab1 and CRM1 during proliferation of lymphoma cells U937].

OBJECTIVE: To investigate the expression and relationship of p27(kip1) and its related molecules Jab1 and CRM1 during proliferation of lymphoma cells U937. METHODS: U937 cells were treated with serum starvation and release, and the effects of these treatments on the cell growth was tested with cell number counting. The expression and localization of p27(kip1), Jab1 and CRM1 in U937 cells were detected by Western blot, double immunolabelling and laser scanning confocal microscopy. RESULTS: The growth of U937 cells was blocked by serum starvation. The total protein of p27(kip1) was increased while Ser10-phosphorylated p27(kip1) -related molecules Jab1 and CRM1 were decreased. Meanwhile, the location of p27(kip1) was changed from cytoplasm into nuclei. After serum release, the location of p27(kip1) expression reappeared in the cytoplasm again. CONCLUSION: During the proliferation process of lymphoma U937 cells, Jab1 and CRM1 may influence the location and expression of p27kip1, and may participate in regulation of growth of NHL cells.

[Expression, localization and interrelationship of P27kip1 and cyclin D3 in non-Hodgkin's lymphoma].

OBJECTIVE: To investigate the expression, localization and interrelationship of P27(kip1) and cyclin D3 in non-Hodgkin's lymphoma (NHL). METHODS: The expressions of P27(kip1), cyclin D3 and index Ki-67 was detected in 100 NHL and 20 reactive lymph nodes by immunohistochemical technique. The expression and localization of P27(kip1) and cyclin D3 in 3 NHL cell lines were detected by Western blot, double immunolabelling and laser scanning confocal microscopy, respectively. RESULTS: In general the expression of P27(kip1) in NHL was lower than in control group, and was negatively related to the tumor aggressiveness and proliferating activity; the expression of cyclin D3 in NHL was higher than in control group, and was positively related to the tumor aggressiveness and proliferating activity. There was a negative correlation between P27(kip1) and cyclin D3. Nevertheless, anomalous high P27(kip1) expression was found in a few NHL tissues with high expression of cyclin D3 and Ki-67. Overexpression and colocalization of P27(kip1) and cyclin D3 was found in Raji cell line. CONCLUSIONS: Under expression of P27(kip1) and overexpression of cyclin D3 may play a role in the occurrence and development of NHL. Anomalous high P27(kip1) expression and its interaction with cyclin D3 may be another mechanism for tumor genesis of NHL.