Mechanistic research:Selenium regulates virulence factors,reducing adhesion ability and inflammatory damage of Helicobacter pylori

BACKGROUND The pathogenicity of Helicobacter pylori is dependent on factors including the environment and the host.Although selenium is closely related to pathogenicity as an environmental factor,the specific correlation between them remains unclear.AIM To investigate how selenium acts on virulence factors and reduces their toxicity.METHODS H.pylori strains were induced by sodium selenite.The expression of cytotoxin-associated protein A(CagA)and vacuolating cytotoxin gene A(VacA)was determined by quantitative PCR and Western blotting.Transcriptomics was used to analyze CagA,CagM,CagE,Cag1,Cag3,and CagT.C57BL/6A mice were infected with the attenuated strains subjected to sodium selenite induction,and H.pylori colonization,inflammatory reactions,and the cell adhesion ability of H.pylori were assessed.RESULTS CagA and VacA expression was upregulated at first and then downregulated in the H.pylori strains after sodium selenite treatment.Their expression was significantly and steadily downregulated after the 5th cycle(10 d).Transcriptome analysis revealed that sodium selenite altered the levels affect H.pylori virulence factors such as CagA,CagM,CagE,Cag1,Cag3,and CagT.Of these factors,CagM and CagE expression was continuously downregulated and further downregulated after 2 h of induction with sodium selenite.Moreover,CagT expression was upregulated before the 3rd cycle(6 d)and significantly downregulated after the 5th cycle.Cag1 and Cag3 expression was upregulated and downregulated,respectively,but no significant change was observed by the 5th cycle.C57BL/6A mice were infected with the attenuated strains subjected to sodium selenite induction.The extent of H.pylori colonization in the stomach increased;however,sodium selenite also induced a mild inflammatory reaction in the gastric mucosa of H.pylori-infected mice,and the cell adhesion ability of H.pylori was significantly weakened.CONCLUSION These results demonstrate that H.pylori displayed virulence attenuation after the 10th d of sodium selenite treatment.Sodium selenite is a low toxicity compound with strong stability that can reduce the cell adhesion ability of H.pylori,thus mitigating the inflammatory damage to the gastric mucosa.

Icariin ameliorates memory deficits through regulating brain insulin signaling and glucose transporters in 3×Tg-AD mice

Icariin,a major prenylated flavonoid found in Epimedium spp.,is a bioactive constituent of Herba Epimedii and has been shown to exert neuroprotective effects in experimental models of Alzheimer’s disease.In this study,we investigated the neuroprotective mechanism of icariin in an APP/PS1/Tau triple-transgenic mouse model of Alzheimer’s disease.We performed behavioral tests,pathological examination,and western blot assay,and found that memory deficits of the model mice were obviously improved,neuronal and synaptic damage in the cerebral cortex was substantially mitigated,and amyloid-βaccumulation and tau hyperphosphorylation were considerably reduced after 5 months of intragastric administration of icariin at a dose of 60 mg/kg body weight per day.Furthermore,deficits of proteins in the insulin signaling pathway and their phosphorylation levels were significantly reversed,including the insulin receptor,insulin receptor substrate 1,phosphatidylinositol-3-kinase,protein kinase B,and glycogen synthase kinase 3β,and the levels of glucose transporter 1 and 3 were markedly increased.These findings suggest that icariin can improve learning and memory impairments in the mouse model of Alzheimer’s disease by regulating brain insulin signaling and glucose transporters,which lays the foundation for potential clinical application of icariin in the prevention and treatment of Alzheimer’s disease.

Inhibitory effects of emodin, baicalin, schizandrin and berberine on hef A gene: Treatment of Helicobacter pylori-induced multidrug resistance

AIM: To investigate the inhibitory effects of emodin, baicalin, etc.on the hefA gene of multidrug resistance(MDR) in Helicobacter pylori(H.pylori).METHODS: The double dilution method was used to screen MDR H.pylori strains and determine the minimum inhibitory concentrations(MICs) of emodin, baicalin, schizandrin, berberine, clarithromycin, metronidazole, tetracycline, amoxicillin and levofloxacin against H.pylori strains.After the screened MDR stains were treated with emodin, baicalin, schizandrin or berberine at a 1/2 MIC concentration for 48 h, changes in MICs of amoxicillin, tetracycline, levofloxacin, metronidazole and clarithromycin were determined.MDR strains with reduced MICs of amoxicillin were selected to detect the hefA mR NA expression by realtime quantitative PCR.RESULTS: A total of four MDR H.pylori strains were screened.Treatment with emodin, baicalin, schizandrin and berberine significantly decreased the MICs of amoxicillin and tetracycline against some strains, decreased by 1 to 2 times, but did not significantly change the MICs of clarithromycin, levofloxacin, and metronidazole against MDR strains.In the majority of strains with reduced MICs of amoxicillin, hef A m RNA expression was decreased; one-way ANOVA(SPSS 12.0) used for comparative analysis, P < 0.05.CONCLUSION: Emodin, baicalin, schizandrin and berberine significantly decreased the MICs of amoxicillin and tetracycline against some H.pylori strains, possibly by mechanisms associated with decreasing hefA mR NA expression.

Expressions of sonic hedgehog, patched, smoothened and Gli-1 in human intestinal stromal tumors and their correlation with prognosis

AIM: To investigate the role that the hedgehog (Hh) signaling pathway, which includes sonic hedgehog (Shh), Patched (Ptc), Smoothened (Smo) and Gli-1, plays in hu- man gastrointestinal stromal tumors (GISTs). METHODS: Surgically resected specimens from pa- tients with GISTs, leiomyomas and schwannomas were examined by immunohistochemical staining for aberrant expression of hedgehog signaling components, Shh, Ptc, Smo and Gli-1, respectively. RESULTS: In GISTs, 58.1% (18 of 31), 77.4% (24 of 31), 80.6% (25 of 31) and 58.1% (18 of 31) of the specimens stained positive for Shh, Ptc, Smo and Gli-1, respectively. In leiomyomas, 92.3% (12 of 13), 92.3% (12 of 13), 69.2% (9 of 13) and 92.3% (12 of 13) stained positive for Shh, Ptc, Smo and Gli-1, respectively. In schwannomas, 83.3% (5 of 6), 83.3% (5 of 6), 83.3% (5 of 6) and 100% (6 of 6) stained positive for Shh, Ptc, Smo and Gli-1, respectively. Immunohistochemistry revealed that the expressions of Shh and Gli-1 were sig- nificantly higher in leiomyomas than in GISTs (P < 0.05, respectively). Shh expression strongly correlated with the grade of tumor risk category and with tumor size (P < 0.05, respectively). However, the expressions of Ptc and Smo did not correlate with histopathological differentiation. CONCLUSION: These results suggest that the Hh sig- naling pathway may play an important role in myogenic differentiation and the malignant potential of human in-testinal stromal tumors.

Expression of vascular endothelial growth factor and its receptors VEGFR-1 and 2 in gastrointestinal stromal tumors,leiomyomas and schwannomas

AIM： To investigate the role of vascular endothelial growth factor （VEGF/and its receptors VEGFR-1 and 2 in the growth and differentiation of gastrointestinal strornal tumors （GISTs）. METHODS： Thirty-three GISTs, 15 leiomyomas and 6 schwannomas were examined by immunohistochemistry in this study. RESULTS： VEGF protein was expressed in the cytoplasm of tumor cells, and VEGFRol and 2 were expressed both in the cytoplasm and on the membrane of all tumors. Irnrnunohistochernical staining revealed that 26 GISTs （78.8%）, 9 leiornyornas （60.0%） and 3 schwannornas （50.0%/were positive for VEGF; 24 GISTs （72.7%/, 12 leiornyornas （80.0%） and 4 schwannornas （66.7%） were positive for VEGFR-1; 30 GISTs （90.9%/, 5 leiornyornas （33.3%/and 4 schwannornas （66.7%） were positive for VEGFR-2. VEGFR-2 expression was statistically different between GISTs and leiomyomas （P 〈 0.0001）. However, there was no correlation between the expression of VEGF pathway componenets and the clinical risk categories. CONCLUSION： Our results suggest that the VEGF pathway may play an important role in the differentiation of GISTs, leiomyomas and schwannomas.

Expression of Angiopoietin-1, 2 and 4 and Tie-1 and 2 in gastrointestinal stromal tumor, leiomyoma and schwannoma

AIM: To investigate the role of angiopoietin (Ang) -1, -2 and -4 and its receptors, Tie-1 and -2, in the growth and differentiation of gastrointestinal stromal tumors (GISTs).METHODS: Thirty GISTs, seventeen leiomyomas and six schwannomas were examined by immunohistochemistry in this study.RESULTS: Ang-1, -2 and -4 proteins were expressed in the cytoplasm of tumor cells, and Tie-1 and -2 were expressed both in the cytoplasm and on the membrane of all tumors. Immunohistochemical staining revealed that 66.7% of GISTs (20 of 30), 76.5% of leiomyomas (13 of 17) and 83.3% of schwannomas (5 of 6) were positive for Ang-1. 83.3% of GISTs (25 of 30), 82.4% of leiomyomas (14 of 17) and 100% of schwannomas (6 of 6) were positive for Ang-2. 36.7% of GISTs (11 of 30), 58.8% of leiomyomas (10 of 17) and 83.3% of schwannomas (5 of 6) were positive for Ang-4. 60.0% of GISTs (18 of 30), 82.4% of leiomyomas and 100% of schwannomas (6 of 6) were positive for Tie-1. 10.0% of GISTs (3 of 30), 94.1% of leiomyomas (16 of 17) and 33.3% of schwannomas (2 of 6) were positive for Tie-2. Tie-2 expression was statistically different between GISTs and leiomyomas (P < 0.001). However, there was no correlation between expression of angiopoietin pathway components and clinical risk categories.CONCLUSION: Our results suggest that the angiopoietin pathway plays an important role in the differentiation of GISTs, leiomyomas and schwannomas.

Icariin ameliorates learning and memory function via improving cerebral glucose metabolism disorder in APP/PS1/Tau triple transgenic Alzheimer disease mice

OBJECTIVE To investigate the protective effect of icariin(ICA) on learning and memory function in APP/PS1/Tau triple transgenic Alzheimer disease mice(3×Tg-AD mice),and then to explore whether its mechanism is related to the improvement of brain glucose metabolism disorder.METHODS Three-month-old male 3 ×Tg-AD mice were randomly divided into three groups(n=10):3×Tg group,3×Tg+ICA low-dose group(30 mg·kg-1) and 3×Tg + ICA high-dose group(60 mg·kg-1).Age-matched male wild type(WT) mice were randomly divided into two groups(n=10):WT control group and WT+ICA60 mg·kg-1 group.ICA in vehicle(0.5% Tween-80 in distilled water) was given orally once a day for five months in the 3×Tg+ICA groups.3×Tg and WT control group were given an equal volume vehicle.Morris water maze was used to detect the learning and memory function of mice.Brain glucose metabolism in 3×Tg mice was observed by 18 F-FDG microPET imaging technique.Nissl staining and HE staining were used to evaluate the survival neurons in hippocampus of mice.Glucose oxidase assay was used to detect glucose contents in cortex of mice.The protein expression of APP,Aβ1-40,Aβ1-42 and glucose transporter 1(GLUT1),and the phosphorylation level of tau protein at multiple sites in hippocampus were detected by Western blotting.RESULTS Behavioral examination revealed a profound decrease learning and memory function,accompanied by a decrease in number of neuronal cells in 3×Tg-AD mice.Moreover,the cerebral18 F-FDG uptake rate per gram tissue was reduced and the glucose contents in the cortex were increased in 3×Tg-AD mice.In addition,Western blotting analysis showed that the expression of APP,Aβ1-40,Aβ1-42 proteins and the levels of tau protein phosphorylation at Ser199/202 and PHF-1(Ser396/404) sites were increased significantly,followed by a decrease of GLUT1 expression in hippocampus of 3×Tg-AD mice.All of these changes in behavioral functions,neuronal loss and related protein expression were reversed when mice were treated with ICA.CONCLUSION ICA can improve the learning and memory ability of AD model mice,the mechanism may be related to the improvement of cerebral glucose metabolism dysfunction by increasing the expression of GLUT1.

Potential effect of hepatitis C Virus non-structural protein 4B on liver carcinogenesis

Objective：To investigate the effect of hepatitis C virus non-structural protein 4B（HCV NS4B） on c-Myc, P53, ras gene expression＂ and apoptosis in hepatic cells and study the possible role that NS4B played in the carcinogenesis of heparoma. Methods： The recombinant plasmid（PCXN2-NS4B, PCXN2-P53） and the empty, vector were transfected or co-transfected into Chang liver cells with liposome. Screening was performed with G418. Plasmid mRNA was detected by RT-PCR. The pro rein expressions of c-Myc and ras genes were analyzed by immunocytochemistry. The expressions of wild-type P53 （wtp53） gene were detected by in situ hybridization. TUNEL（flow cytometry） was used for assessing the rate of apoptosis. Results：No expression of c-Myc gene was found in PCXN2 group. The expression of c-Myc gene in NS4B group was 21.3% ＋ 1.2%. The ex pression of ras gene in PCXN2 group was lower than that in NS4B group. Compared with PCXN2 group, the expression of P53 mRNA was not promoted or inhibited in NS4B group. But the expression of P53 mRNA in NS4B-P53 group was lower than that in P53 group. In PCXN2, NS4B, P53 and NS4B-P53 group, the rates of apoptosis were 17.02% ± 1.24%, 11.94% ± 2.24%, 25.84% ± 3.49% and 18.34% ± 1.55% respectively. Conclusion ：HCV NS4B induces the expression of c-Myc and ras gene. HCV NS4B may play a role in the inhibition of cell death through P53-dependent manner. Results from this study suggested that HCV NS4B might contribute to the viral carcinogenesis.

RNA interference against interleukin-5 attenuates airway inflammation and hyperresponsiveness in an asthma model

Interleukin-5 (IL-5) accompanies the development of airway inflammation and hyperresponsiveness through the activation of eosinophils. Therefore, interference of IL-5 expression in lung tissue seems to be an accepted approach in asthma therapy. In this study, we designed a small interfering RNA (siRNA) to inhibit the expression of IL-5. The siRNAs against IL-5 were constructed in a lentivirus expressing system, and 1.5×106 IFU (inclusion-forming unit) lentiviruses were administered intratracheally to ovalbumin (OVA)-sensitized murine asthmatic models. Our results show that lentivirus-delivered siRNA against IL-5 efficiently inhibited the IL-5 messenger ribonucleic acid (mRNA) expression and significantly attenuated the inflammation in lung tissue. Significant decrease of eosinophils and inflammatory cells were found in peripheral blood, bronchoalveolar lavage fluid (BALF), and lung tissue. In addition, significant inhibition of airway hyperresponsiveness (AHR) was found in the mice treated with siRNA against IL-5. These observations demonstrate that siRNA delivered by means of the lentivirus system is possibly an efficacious therapeutic approach for asthma.

A possible endoscopic therapy for large hiatal hernia complicated with refractory gastroesophageal reflux disease

A hiatal hernia(HH)is usually associated with gastroesophageal reflux disease(GERD).An HH can increase the incidence of GERD.[1]The coexistence of these diseases increases the difficulty of treatment and can be challenging for endoscopic treatment.Therapeutic methods for small HHs(≤2 cm)combined with refractory GERD have recently been emerging.However,there are still knowledge gaps in the endoscopic treatment of large HHs(≥3cm)combined with refractory GERD.We developed a new endoscopic method called hiatal hernia-endoscopic submucosal dissection(HH-ESD)and performed the present study to clarify the efficacy and safety of HH-ESD.