TNF-α-inducing protein of Helicobacter pylori induces epithelial-mesenchymal transition (EMT) in gastric cancer cells through activation of IL-6/STAT3 signaling pathway.

Tumor necrosis factor (TNF)-α-inducing protein (Tipα) is a newly identified carcinogenic factor secreted by Helicobacter pylori (H. pylori). Although it has been proved that Tipα is a strong inducer of epithelial-mesenchymal transition (EMT), a crucial process of migration, the exact molecular mechanism is unknown. Current evidence indicates that the oncogenic transcription factor signal transducers and activators of transcription 3 (STAT3) is inappropriately activated in multiple malignancies, including gastric cancer. In this study, we showed that Tipα significantly down-regulated the expression of EMT-related markers E-cadherin as well as up-regulated N-cadherin and vimentin in SGC7901 cells, with typical morphological changes of EMT. Tipα also promoted proliferation and migration of SGC7901 cells. Furthermore, Tipα activated interleukin-6 (IL-6)/STAT3 signaling pathway in SGC7901 cells. The effects of Tipα treatment observed was abolished when we block IL-6/STAT3 signaling pathway. Altogether, our data demonstrated that Tipα may accelerate tumor aggressiveness in gastric cancer by promoting EMT through activation of IL-6/STAT3 pathway.

Deficiency of LIGHT signaling pathway exacerbates Chlamydia psittaci respiratory tract infection in mice.

LIGHT, a costimulatory member of the immunoglobulin superfamily (Ig SF), can greatly impact T cell activation. The role of the LIGHT signaling pathway in chlamydial infection was evaluated in mice following respiratory tract infection with Chlamydia psittaci. Compared with wild type (WT) mice, LIGHT knockout (KO) mice showed significant reduction of body weight, much lower survival rate, higher bacterial burden, prolonged infection time courses and more severe pathological changes in lung tissue. The mRNA levels of IFN-γ, TNF-α, IL-17 and IL-12 in the lung tissue of LIGHT KO mice were significantly lower than those in WT mice. While there was no obvious difference in the percentages of CD4+ and CD8+ T cells in the spleens of the two groups of mice, there was a markedly elevated percentage of CD4+ CD25+ FoxP3+ Treg cells in LIGHT KO mice. Together, these results demonstrate that the LIGHT signaling pathway is not only required for inflammatory cytokine production as part of the host response to chlamydial infection, but also influences the differentiation of CD4+ CD25+ FoxP3+ Treg cells, both of which may be essential for control of C. psittaci respiratory tract infection.

CD4(+) Foxp3(+) regulatory T-cell number increases in the gastric tissue of C57BL/6 mice infected with Helicobacter pylori.

Helicobacter pylori (H. pylori), one of the most common infections, is associated with various clinical outcomes. In addition to inducing inflammation, immunological clearance of the pathogen is often incomplete. Regulatory T cells (Treg cells) have been recently demonstrated to play an important role in H. pylori infection and the final clinical outcome. The aim of this study was to investigate the number and localization of CD4(+) Foxp3(+) Treg cells in stomachs and spleens of H. pylori-infected mice. The expression levels of Foxp3 as well as anti- and pro-inflammatory cytokines before and after H. pylori triple eradication therapy were examined. We found that the percentages of CD4(+) Foxp3(+) Treg cells out of the lamina propria lymphocytes (LPLs) and spleen lymphocytes in the infection group were higher than the PBS negative control group and the treatment group. H. pylori antigen stimulation was associated with an increased number of Treg cells in vitro. Furthermore, compared with the PBS and treatment groups, a higher mRNA expression level of Foxp3 in the gastric tissue was detected in the infection group. IL-10 and TGF-ß1 contents were increased significantly in the culture supernatant of spleen lymphocyte stimulated with H. pylori antigen. A marked elevation in serum IFN-γ level was observed in H. pylori-infected mice. In addition, gastric tissues of the infection group contained more Foxp3(+) cells. These results indicate that the percentage of CD4(+) Foxp3(+) Treg cells are increased in H. pylori-infected mice, suggesting a role of Treg cells in H. pylori-induced pathologies, even at the early stages of chronic gastritis and gastric tumorigenesis.

Awareness and knowledge about human papillomavirus among high school students in China.

OBJECTIVE: To investigate awareness and knowledge of human papillomavirus (HPV) infection among high school students and to provide a basis for health education on HPV infection for high school students in China. STUDY DESIGN: A questionnaire on HPV awareness and knowledge was administered to 900 high school students in Xiangtan City of Hunan Province in China by layer cluster sampling. A total of 848 anonymous valid questionnaires were received from volunteers who completed the questionnaire correctly. RESULTS: Only 10.1% had heard of HPV, and of those only 18.6% knew that HPV could lead to cervical cancer. Single factor analysis indicated that home address, age, grade, academic achievement, sex history, gender, father's education level and mother's education level were impact factors for HPV knowledge of high school students. Multiple regression analysis showed 4 independent risk factors associated with HPV knowledge: academic achievement, sex history, gender, and mother's education level. The limited knowledge came primarily from television and radio broadcasts (59.3%), the Internet (57.0%), parents (25.6%), medical workers (20.9%), and teachers (18.6%). CONCLUSION: High school students lack HPV knowledge, which is affected by multiple factors. Targeted health education of all sorts must be provided. Both schools and families are responsible for reinforcing HPV education provided to high school students.

Overexpression of Helicobacter pylori VacA N-terminal fragment induces proinflammatory cytokine expression and apoptosis in human monocytic cell line through activation of NF-κB.

Vacuolating cytotoxin (VacA) is an important virulence factor in the pathogenesis of Helicobacter pylori-related diseases. The aim of this study was to investigate the function of the amino-terminal 476 residue fragment (p52) of VacA and the possible molecular mechanisms responsible for its induction of proinflammatory cytokines secretion and apoptosis. Human acute monocytic leukemia cell line THP-1 was used as an in vitro model to study proinflammatory cytokines secretion and apoptosis induced by transfection of a recombinant plasmid encoding the amino-terminal 476 residue fragment (p52) of VacA. The results showed that VacA p52 overexpression induced the production of tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1ß), nitric oxide, and reactive oxygen species in THP-1 cells in a time-dependent manner. VacA p52 overexpression also promoted THP-1 cells apoptosis. In addition, VacA p52 triggered the activation of nuclear factor kappa B (NF-κB), indicating a possible mechanism for its induction of proinflammatory cytokines secretion and cell apoptosis. Our study demonstrated that the induction of cytokines secretion and apoptosis by VacA p52 in THP-1 cells could be mediated through activation of nuclear factor kappa B.

[The expressions of NLRP3 inflammasome and its downstream molecules in the mouse model of Helicobacter pylori infection].

OBJECTIVE: To study the expressions of NLRP3 inflammasome and its downstream molecules in the gastric tissues and sera of Helicobacter pylori (H.pylori)-infected C57BL/6 mice, and to preliminary explore the role of NLRP3 inflammasome signalling pathway in the pathogenesis of H.pylori infection. METHODS: C57BL/6 mice were randomly divided into H.pylori infection group and PBS control group, and mice were sacrificed at different time points after H.pylori infection. The mRNA expressions of NLRP3 inflammasome and downstream signalling pathway related molecules in mouse gastric tissues were detected by RT-PCR, and the protein level of caspase-1 was analyzed by Western blotting. The contents of IL-1ß, IL-18 and IL-33 in the sera were measured with ELISA. RESULTS: Chronic inflammatory response was observed in the gastric mucosal tissues of H.pylori-infected mice and it gradually aggravated. Compared with the control mice, the mRNA expressions of NLRP3 inflammasome signalling pathway related molecules and the protein level of caspase-1 increased markedly in the gastric tissues of H.pylori-infected mice. Moreover, the contents of IL-1ß, IL-18 and IL-33 in the sera of H.pylori-infected mice were also significantly elevated. CONCLUSION: NLRP3 inflammasome signalling pathway could be activated by H.pylori infection.

Transcriptional repression of hDaxx enhanced by adenovirus 12 E1B 55-kDa oncoprotein interacting with hDaxx.

BACKGROUND: Daxx has been identified as a nuclear protein that involves in apoptosis and transcriptional repression. Daxx co-localizes with the promyelocytic leukemia (PML) protein and regulates transcription. Human Daxx (hDaxx) is a protein that functions as a transcriptional regulation through its interaction with some DNA-associated proteins. The aim of this study was to explore the transcriptional regulatory effect of hDaxx interacting with adenovirus (Ad) 12 E1B (Ad12E1B) 55-kDa oncoprotein. METHODS: The co-localization of hDaxx-Ad12E1B or hDaxx-PML protein in the nucleus was observed under a confocal microscope. Interaction of hDaxx and Ad12E1B was analyzed by yeast two-hybrid assay. Direct binding of hDaxx and Ad12E1B was analyzed using coimmunoprecipitation and Western blot in vivo and in vitro. The activity of a luciferase reporter gene, which was regulated by an hDaxx modulated thymidine kinase (TK) promoter, was detected in an automat luminometer. RESULTS: Ad12E1B, which co-localized with hDaxx in the nuclei of G401-CC3 cells, disrupted the co-localization of hDaxx and PML in the PML oncogenic domains (PODs). hDaxx bound directly to Ad12E1B in vivo and in vitro. hDaxx interacted with Ad12E1B along its full length. Ad12E1B enhanced transcriptional repression activity of hDaxx. CONCLUSION: Ad12E1B disrupts the co-localization of hDaxx with PML in PODs and enhances transcriptional repression activity of hDaxx.