Alphavbeta6 is required in maintaining the intestinal epithelial barrier function.

Epithelial barrier dysfunction is involved in a large number of diseases, but the pathogenesis is unclear. Integrin alphavbeta6 (avb6) in involved in the maintenance of the mucosal homeostasis. We have investigated the role of avb6 in maintaining the epithelial barrier function. Using T84 monolayers cultures, transepithelial electric resistance (TER) and permeability to ovalbumin (OVA) were measured as indicators of functioning. The antigenicity of OVA collected from the Transwell basal chambers was assessed using OVA-specific T cell proliferation. Knockdown of the avb6 genes increased the permeability of T84 monolayers to OVA, but did not affect TER. The deficiency of avb6-related hyperpermeability in T84 monolayers could be compensated by adding exogenous avb6 to the culture. The OVA samples collected from the basal chambers had strong antigenicity as it markedly induced the antigen specific T cell proliferation. Addition of recombinant avb6 blocked increases in permeability of T84 monolayers to OVA induced by tumor necrosis factor-α.

Overexpression of ARK5 is associated with poor prognosis in hepatocellular carcinoma.

ARK5 overexpression has been reported in a variety of human cancers. However, the role of ARK5 in hepatocellular carcinoma (HCC) remains unclear. The aim of the present study is to analyze the ARK5 protein expression in HCC tissue samples and to assess its prognostic significance for HCC. ARK5 mRNA and protein expression were determined by real-time quantitative reverse transcriptase-polymerase chain reaction and Western blot in 20 pairs of fresh frozen HCC tissues and corresponding non-cancerous tissues. In addition, ARK5 expression was analyzed by immunohistochemistry in 130 clinicopathologically characterized HCC cases. The correlation of ARK5 expression with patients' survival rate was assessed by Kaplan-Meier and Cox regression. Our results showed that the expression levels of ARK5 mRNA and protein in HCC tissues were both significantly higher than those in non-cancerous tissues. Our results showed that the high expression of ARK5 in HCC was related to tumor size (p=0.005), histological differentiation (p=0.047), and tumor stage (p=0.005). Kaplan-Meier survival analysis showed that a high expression level of ARK5 resulted in a significantly poor prognosis of HCC patients. Multivariate analysis revealed that ARK5 expression level was an independent prognostic parameter for the overall survival rate of HCC patients. In conclusion, ARK5 might play a positive role in tumor development and could serve as an independent predictor of poor prognosis for HCC.

Oral Bifidobacterium modulates intestinal immune inflammation in mice with food allergy.

BACKGROUND AND AIMS: It is proposed that probiotics have a therapeutic effect on the treatment of immune disorders. However, the underlying mechanisms require clarification. The present study aimed to evaluate the effect of gavage-feeding Bifidobacteria on suppression of T helper 2 (Th2) pattern inflammation in the intestines of mice with food allergy. METHODS: Mice were sensitized to ovalbumin to induce the intestinal Th2 pattern inflammation. Allergic mice were treated with or without Bifidobacteria via gavage-feeding. Th2 response, number of regulatory T cells (Treg) in the spleen and intestine, intestinal epithelial barrier function and bifidobacterial translocation were examined. RESULTS: The results showed that serum-specific immunoglobulin E antibody and interleukin 4 (IL-4) were increased in allergic mice. Intestinal epithelial barrier function was impaired in allergic mice as shown by the increase in epithelial ion secretion and permeability to macromolecular protein horseradish peroxidase in Ussing chambers. Number of Treg was decreased in both spleen and intestines of allergic mice. Gavage-feeding Bifidobacteria significantly suppressed the skewed Th2 response and increased the number of Treg. Transient bifidobacterial translocation was observed in allergic mice. CONCLUSIONS: Oral administration of Bifidobacteria has the capacity to suppress the skewed Th2 response in allergic mice, increasing the number of Treg and IL-10-positive cells and improve the impaired intestinal epithelial barrier function.

[In vivo antitumor effect of canstatin gene on human esophageal carcinoma xenografts in nude mice].

BACKGROUND AND OBJECTIVE: Canstatin is a newly discovered endogenous inhibitor of angiogenesis. Previous study has shown that canstatin can efficiently suppress the growth of human cancers, even more potent than endostatin. This study was to investigate the antitumor effects of canstatin gene on human esophageal carcinoma xenografts. METHODS: Tumor xenografts were induced with KYSE150 cells in BALB/c nude mice, and randomized into three groups: PBS, adenovirus green fluorescent protein (Ad-GFP), and Ad-GFP-canstatin groups. During treatment, tumor size was measured. The mice were killed 30 days later to observe tumor morphology. The expression of vascular endothelial growth factor (VEGF), fetal liver kinase-1 (Flk-1), caspase-3 and microvessel density (MVD) were detected by immunohistochemistry. RESULTS: Compared with that in Ad-GFP and PBS groups, tumor growth in Ad-GFP-canstatin group was significantly suppressed in the first week after gene transfection. The inhibition rate of tumor growth was up to 61% at the sixth day. Necrotic regions were observed in all groups, especially in Ad-GFP-canstatin group. Compared with those in Ad-GFP and PBS groups, caspase-3 expression in Ad-GFP-canstatin group was higher (P<0.05), while Flk-1 expression and MVD was lower (P<0.05). There was no obvious difference in VEGF expression among the three groups. CONCLUSION: Canstatin can inhibit the growth of human esophageal carcinoma by suppressing angiogenesis via down-regulating Flk-1 expression.

[Pseudotyping of murine leukemia virus particles with porcine reproductive and respiratory syndrome virus M protein-mediated E protein].

For constructing pcDNA-ORF5, pcDNA-ORF5-ORF6, pcDNA-ORF5/6, the ORF5 and ORF6 of porcine reproductive and respiratory syndrome virus (PRRSV) were amplified by RT-PCR, and transiently transfected into 293T cells by calciumphosphate co-precipitation. After 48 h, 293T cells were collected and surveyed by flow cytometry examination. The result indicated that the expression level of the E protein that mediated by the M protein was higher than that of the E protein expressed independently. Then pcDNA-ORF5, pcDNA-ORF5-ORF6, pcDNA-ORF5/6 were respectivly co-transfected into 293T cells with pHIT60 (include MuLV structural genes,namely gag and pol) and pHIT111 (retroviral genome, containing LacZ as a reporter). The supernatants were harvested 48 h post-transfection,and the analysis of the characteristic of the pseudotyping virions was performed by Western blot and infection test. The result indicated that the E proteins were expressed on the virions, and incorporated into the retroviral virions. Infection test were performed on Marc-145 and PAM, all the cells infected were Lac Z positive. These results indicated the pseudotype virions of MuLV-E and MuLV-E/M were infectious, and higher infectivity was achieved by MuLV-E/M.

Entecavir up-regulates dendritic cell function in patients with chronic hepatitis B.

AIM: To investigate the in vitro effect of entecavir (ETV) on the function of dendritic cells (DCs) derived from chronic hepatitis B (CHB) patients. METHODS: Mononuclear cells were isolated from peripheral blood of patients with CHB. DCs were incubated with RPMI-1640 medium supplemented with fetal bovine serum, IL-4, granulocyte-macrophage colony-stimulating factor (GM-CSF). DCs were treated with or without ETV on the fourth day. Cell surface molecules, including CD1a, CD80, CD83 and HLA-DR, were assessed by flow cytometry. Concentrations of IL-6 and IL-12 in the supernatant were assayed by enzyme-linked immunosorbent assay (ELISA). The ability of the generated DCs to stimulate lymphocyte proliferation was observed. RESULTS: Compared with CHB control group, the expression levels of CD1a (29.07 +/- 3.20 vs 26.85 +/- 2.80), CD83 (25.66 +/- 3.19 vs 23.21 +/- 3.10), CD80 (28.00 +/- 2.76 vs 25.75 +/- 2.51) and HLA-DR (41.96 +/- 3.81 vs 32.20 +/- 3.04) in ETV-treated group were higher (P < 0.05). ETV-treated group secreted significantly more IL-12 (157.60 +/- 26.85 pg/mL vs 132.60 +/- 22.00 pg/mL (P < 0.05) and had a lower level of IL-6 in the culture supernatant (83.05 +/- 13.88 pg/mL vs 93.60 +/- 13.61 pg/mL, P < 0.05) than CHB control group. The ability of DCs to stimulate the proliferation of allogeneic lymphocytes was increased in ETV-treated group compared with CHB control group (1.53 +/- 0.09 vs 1.42 +/- 0.08, P < 0.05). CONCLUSION: Entecavir can enhance the biological activity of DCs derived from CHB patients.

Effects of lamivudine on the function of dendritic cells derived from patients with chronic hepatitis B virus infection.

AIM: To investigate if the nucleoside analogue lamivudine (LAM), a potent inhibitor of HBV replication, could restore the function of dendritic cells derived from patients with chronic hepatitis B (CHB) in an Asian population. METHODS: Dendritic cells (DCs) derived from mononuclearcytes of patients with chronic HBV infection were cultured in the presence of IL-4, granulocyte-macrophage colony-stimulating factors (GM-CSF) and gradient concentrations of LAM (0-2 mmol/L). Cell morphology was observed under light microscopy. Cell surface molecules, including HLA-DR, CD80, CD83, and CD1alpha, were analyzed with flow cytometry. The concentrations of IL-6 and IL-12 in the supernatant were assayed by ELISA. T cell proliferation was assayed by methyl thiazolyl tetrazolium (MTT). RESULTS: The expression of CD1alpha on DC treated with 0.5 mmol/L LAM (LAM-DC 0.5 mmol/L) was significantly higher than that of DC untreated with LAM (54.1 +/- 4.21 vs 33.57 +/- 3.14, P < 0.05), and so was the expression of CD83 (20.24 +/- 2.51 vs 12.83 +/- 2.12, P < 0.05) as well as the expression of HLA-DR (74.5 +/- 5.16 vs 52.8 +/- 2.51, P < 0.05). Compared with control group, LAM-DC group (0.5 mmol/L) secreted significantly more IL-12 (910 +/- 91.5 vs 268 +/- 34.3 pg/mL, P < 0.05), had lower levels of IL-6 in the culture supernatant (28 +/- 2.6 vs 55 +/- 7.36 pg/mL, P < 0.05), markedly enhanced the stimulatory capacity in the allogeneic mixed leukocyte reaction (MLR) (1.87 +/- 0.6 vs 1.24 +/- 0.51, P < 0.05). CONCLUSION: The lower expression of phenotypic molecules and impaired allogeneic mixed lymphocyte reaction function of dendritic cells derived from patients with HBV infection could be restored in vitro by incubation with LAM.