RAGE participates in the intracellular transport of Campylobacter jejuni cytolethal distending toxin.

BACKGROUND: Cytolethal distending toxin (CDT) belongs to the genotoxin family and is closely related to Campylobacter jejuni-associated gastroenteritis. We recently reported that CDT triggers the danger-associated molecular pattern (DAMP) signaling to exert deleterious effects on host cells. However, how CDT traffics in cells and the mechanism of CDT intoxication remain to be elucidated. METHODS: Recombinant CDT subunits (CdtA, CdtB, and CdtC) were purified, and their activity was characterized in gastrointestinal cells. Molecular approaches and image tracking were employed to analyze the delivery of CDT in host cells. RESULTS: In this study, we found that CDT interacts with the receptor of advanced glycation end products (RAGE) and high mobility group box 1 (HMGB1) to enter the cells. Our results further showed that CdtB transport in cells through the dynamin-dependent endocytic pathway and lysosome is involved in this process. Conversely, blockage of RAGE signaling resulted in a reduction in CDT-arrested cell cycles, indicating that RAGE is involved in CDT intracellular transport and its subsequent pathogenesis. CONCLUSION: Our results demonstrate that RAGE is important for CDT trafficking in the cells. These findings expand our understanding of important issues related to host cell intoxication by C. jejuni CDT.

Raloxifene Protects Cisplatin-Induced Renal Injury in Mice via Inhibiting Oxidative Stress.

PURPOSE: Cisplatin is one of the most widely used antineoplastic drugs but has limited therapeutic effects due to nephrotoxicity. The aim of this study was to determine the possible renoprotective effect of the antioxidant raloxifene on cisplatin-induced nephrotoxicity in mice. MATERIALS AND METHODS: Cisplatin-induced acute renal injury was established in female C57 mice that were treated with saline (normal control) or raloxifene over a 7-day period. The body weight of the mice was recorded. Histopathological examinations of the kidney tissues were performed using H&E, PAS staining and TEM. The histomorphology of liver and other organs was observed by H&E staining. The serum levels of creatinine, blood urea nitrogen (BUN), alanine transaminase (ALT) and glutamic oxalacetic transaminase (AST) were analyzed by specific kits. Superoxide dismutase (SOD) and glutathione (GSH) activity, and the content of malondialdehyde (MDA) in the kidney, liver homogenates and HK-2 cells were measured by WST-8 and thiobarbituric acid colorimetric methods. Moreover, the mitochondrial structures of HK-2 cells were performed using TEM. The viability and proliferation of HK-2 cells were examined by CCK-8 and EdU incorporation assays. The mitochondrial membrane potential was measured by JC-1 fluorescence. RESULTS: Raloxifene significantly reduced the levels of serum creatinine, urea, ALT and AST in the cisplatin-treated mice, and alleviated cisplatin-induced renal and hepatic tissue injury. Furthermore, raloxifene also increased the activity of GSH and SOD in the renal tissues and HK-2 cells, and reduced MDA levels, thereby limiting oxidative stress in the kidney. CONCLUSION: Raloxifene protected against cisplatin-induced nephrotoxicity by activating the antioxidant system, along with alleviating liver damage. It should be considered as a potential adjuvant in cisplatin-based chemotherapeutic protocols.

Helicobacter pylori cholesterol-α-glucosyltransferase manipulates cholesterol for bacterial adherence to gastric epithelial cells.

Helicobacter pylori infection is associated with several gastrointestinal diseases, including gastritis, peptic ulcers, and gastric cancer. Infection of cells with H. pylori is dependent on lipid rafts, which are cholesterol-rich microdomains located in the cell membrane. H. pylori cholesterol-α-glucosyltransferase (CGT) catalyzes the conversion of membrane cholesterol to cholesteryl glucosides, which can be incorporated into the bacterial cell wall, facilitating evasion from immune defense and colonization in the host. However, the detailed mechanisms underlying this process remain to be explored. In this study, we discovered for the first time that H. pylori CGT could promote adherence to gastric epithelial cells in a cholesterol-dependent manner. Externalization of cell membrane phosphatidylserine (PS) is crucial for enhancement of binding of H. pylori to cells by CGT and for cytotoxin-associated gene A (CagA)-induced pathogenesis. Furthermore, exogenous cholesterol interferes with the actions of H. pylori CGT to catalyze cellular cholesterol, which impedes bacterial binding to cells and attenuates subsequent inflammation, indicating that the initial attachment of H. pylori to cells is closely dependent on host cholesterol. These results provide evidence that CGT contributes to H. pylori infectivity and it may serve as a key target for the treatment of H. pylori-associated diseases.

Normal Basal Epithelial Cells Stimulate the Migration and Invasion of Prostate Cancer Cell RM-1 by TGF-ß1/STAT3 Axis in vitro.

AIM: Basal epithelial cells are absent in distant prostate cancer. This study aimed to investigate whether basal epithelial cells could suppress migration and invasion of prostate cancer cells to become a new treatment strategy for prostate cancer. MAIN METHODS: Basal epithelial cells were identified by immunofluorescence with anti-p63. Wound healing assays or transwell assays were used to explore the effects of basal epithelial cells, TGF-ß1, SB431542 (inhibitor of TGF-ß type I receptor) or stattic (inhibitor of phosphorylated STAT3) on migration or invasion of mouse prostate cancer cell (RM-1). Concentration of TGF-ß1 was measured by ELISA assay. HE staining was used to investigate cell morphology. Immunocytochemistry with anti-p63 was used to identify basal epithelial cells. Levels of STAT3, p-STAT3 (Ser727) and proteins associated with EMT were measured with Western blot assay. Cell proliferation was measured with MTT or CCK8 assay. RESULTS: Normal basal epithelial cells acquired from mouse prostate were specific to anti-p63 and more than 90%. Basal epithelial cells and RM-1 could both secrete TGF-ß1. Basal epithelial cells and TGF-ß1 promoted the migration and invasion of RM-1 through changing the cell morphology and up-regulating expression of ZEB1, N-cadherin, vimentin, snail and p-STAT3 (Ser727), at the same time down-regulating E-cadherin of RM-1. SB431542 strongly suppressed migration, invasion as well as the expressions of EMT relevant proteins and p-STAT3 (Ser727) of co-cultured RM-1. In addition, stattic suppressed proliferation, migration and invasion of non-treated RM-1 and co-cultured RM-1. CONCLUSION: Our study suggests that normal basal epithelial cells might stimulate the migration and invasion of RM-1 by TGF-ß1/STAT3 axis which could be suppressed by inhibitor of TGF-ß receptor and inhibitor of p-STAT3. So, basal epithelial cells might not become a treatment strategy for prostate cancer, but our results could provide some researching references for other diseases which include basal epithelial cells such as prostatic intraepithelial neoplasia, prostatic hyperplasia, cervical cancer, or urinary bladder cancer.

Helicobacter pylori Induces IL-33 Production and Recruits ST-2 to Lipid Rafts to Exacerbate Inflammation.

Helicobacter pylori colonizes human gastric epithelial cells and contributes to the development of several gastrointestinal disorders. Interleukin (IL)-33 is involved in various immune responses, with reported proinflammatory and anti-inflammatory effects, which may be associated with colitis and colitis-associated cancer. IL-33 induces the inflammatory cascade through its receptor, suppression of tumorigenicity-2 (ST-2). Binding of IL-33 to membrane-bound ST-2 (mST-2) recruits the IL-1 receptor accessory protein (IL-1RAcP) and activates intracellular signaling pathways. However, whether IL-33/ST-2 is triggered by H. pylori infection and whether this interaction occurs in lipid rafts remain unclear. Our study showed that both IL-33 and ST-2 expression levels were significantly elevated in H. pylori-infected cells. Confocal microscopy showed that ST-2 mobilized into the membrane lipid rafts during infection. Depletion of membrane cholesterol dampened H. pylori-induced IL-33 and IL-8 production. Furthermore, in vivo studies revealed IL-33/ST-2 upregulation, and severe leukocyte infiltration was observed in gastric tissues infected with H. pylori. Together, these results demonstrate that ST-2 recruitment into the lipid rafts serves as a platform for IL-33-dependent H. pylori infection, which aggravates inflammation in the stomach.

Aggregate analysis based on TCGA: TTN missense mutation correlates with favorable prognosis in lung squamous cell carcinoma.

PURPOSE: Lung cancer prevalence with its high mortality rate is a trending topic globally. Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. The human gene TTN encoding for TITIN protein is known as major mutation gene in many types of tumor including NSCLC. However, it is still controversial that TTN is a cancer-associated candidate considering tumor heterogeneity and complex genetic structure. In-depth researches on correlation between TTN mutation and NSCLC are still limited and discussable. METHODS: Related somatic mutation profiles and attached clinical data were from The Cancer Genome Atlas (TCGA) lung project. Clinical relevance analysis of TTN mutation was evaluated using univariate analysis and a binary logistic regressive model. Survival analysis and screening of independent prognostic factors in mutation types were conducted by Cox proportional hazards models and Kaplan-Meier methods. RESULTS: Available data covering lung adenocarcinoma (n = 517) and lung squamous cell carcinoma (n = 492) were analyzed. TTN genetic mutations exhibited significant association with lung squamous cell carcinoma. Patients with lung squamous cell carcinoma possessed favorable overall survival benefits from TTN mutant type and both favorable overall survival and disease-free survival benefits from TTN/TP53 double mutation. For patients with lung squamous cell carcinoma, about 85% of subjects with TTN mutation harbored missense variations, which was an independent indicator of good prognosis. CONCLUSIONS: Missense mutation of TTN may act as a beneficial role in lung squamous cell carcinoma, but not in lung adenocarcinoma.

Probiotic Lactobacillus spp. act Against Helicobacter pylori-induced Inflammation.

The bacterial species, Helicobacter pylori, is associated with several gastrointestinal diseases, and poses serious health threats owing to its resistance to antibiotics. Lactobacillus spp., on the other hand, possess probiotic activities that have beneficial effects in humans. However, the mechanisms by which Lactobacillus spp. harbor favorable functions and act against H. pylori infection remain to be explored. The aim of this study was to investigate the ability of bacterial strains, Lactobacillus rhamnosus and Lactobacillus acidophilus, termed GMNL-74 and GMNL-185, respectively, to inhibit H. pylori growth and inflammation. Our results showed that GMNL-74 and GMNL-185 possess potent antimicrobial activity against multidrug resistant (MDR)-H. pylori. In addition, an in vitro cell-based model revealed that the inhibition of H. pylori adhesion and invasion of gastric epithelial cells and interleukin-8 production were significantly decreased by treatment with both the Lactobacillus strains. In vivo studies demonstrated that colonization of H. pylori and induced inflammation in the mouse stomach were also alleviated by these Lactobacillus strains. Furthermore, the abundance of beneficial gut bacteria, including Bifidobacterium spp. and Akkermansia muciniphilia, were significantly increased in H. pylori-infected mice treated with GMNL-74 and GMNL-185. These results demonstrate that Lactobacillus spp. ameliorate H. pylori-induced inflammation and supports beneficial gut specific bacteria that act against H. pylori infection.