Novel 2, 8-bit derivatives of quinolines attenuate Pseudomonas aeruginosa virulence and biofilm formation.

Signal molecules are stimulators of multiple quroum-sensing virulence and biofilm formation. Small molecule analogues have been suspected as a potent inhibitor in therapeutic strategy. Herein, we synthesized a series of small molecule compounds from the 2, 8-bit derivatives of quinoline by Suzuki coupling reaction. We found that these compounds have the biofilm inhibitory effect in normal condition instead of phosphate limitation state. Furthermore, lacZ reporter strain assay and rhamnolipids as well as pyocyanin experiments showed that these compounds did not affect las and pqs system but reduced the expression of rhl. All these results suggest that quinoline derivatives can be treated as potent inhibitors against biofilm and reduce virulence through the rhl system. This research will be useful in designing new quorum sensing inhibitors to attenuate the infection of bacteria.

RIP3 deficiency exacerbates inflammation in dextran sodium sulfate-induced ulcerative colitis mice model.

Ulcerative colitis (UC) is a chronic intestinal inflammatory disease. The receptor-interacting protein kinase 3 (RIP3) was reported to be involved in many inflammatory disease. However, the mechanism of RIP3 in the pathogenesis of UC is still unclear. To investigate the effects and possible mechanism of RIP3 in UC pathogenesis, RIP3-/- mice was used in dextran sulfate sodium (DSS)-induced colitis model. It was found that by DSS-induced colitis, RIP3-/- mice showed significantly enhanced colitis symptoms, including increased weight loss, colon shortening, and colonic mucosa damage and severity, but decreased production of interleukin 6 and interleukin 1ß. The results showed that RIP3 deficiency could not ameliorate but exacerbate the severity of colitis. On the mechanism, it was found that messenger RNA expressions of several repair-associated cytokines including interleukin 6, interleukin 22, cyclooxygenase 2, epithelial growth factor receptor ligand Epiregulin and matrix metalloproteinase 10 were siginificant decreased in RIP3-/- mice. Thus, RIP3-/- mice exhibited an impaired tissue repair in response to DSS. In a conclusion, RIP3 deficiency exerted detrimental effects in DSS induced colitis partially because of the impaired repair-associated cytokines expression.

Trachelogenin, a novel inhibitor of hepatitis C virus entry through CD81.

Although much progress has been made in antiviral agents against hepatitis C virus (HCV) in recent years, novel HCV inhibitors with improved efficacy, optimized treatment duration and more affordable prices are still urgently needed. Here, we report the identification of a natural plant-derived lignan, trachelogenin (TGN), as a potent entry inhibitor of HCV without genotype specificity, and with low cytotoxicity. TGN was extracted and purified from Caulis trachelospermi, a traditional Chinese herb with anti-inflammatory and analgesic effects. A crucial function of TGN was the inhibition of HCV entry during a post-binding step without affecting virus replication, translation, assembly and release. TGN blocked virus infection by interfering with the normal interactions between HCV glycoprotein E2 and the host entry factor CD81, which are key processes for valid virus entry. In addition, TGN diminished HCV cell-to-cell spread and exhibited additional synergistic effects when combined with IFN or telaprevir. In conclusion, this study highlights the effect of a novel HCV entry inhibitor, TGN, which has a target that differs from those of the current antiviral agents. Therefore, TGN is a potential candidate for future cocktail therapies to treat HCV-infected patients.

Hepatitis C virus F protein inhibits cell apoptosis by activation of intracellular NF-kappaB pathway.

AIM: To observe the influence of HCV F protein on apoptosis of HepG2 cells, and explore the association between F protein and NF-kappaB signal pathway. METHODS: HCV 1b F gene containing HepG2-F cells and HCV 1b C gene containing HepG2-C cells were treated with 100 IU/mL TNF-alpha, and analyzed by flow cytometry, Western blotting, and dual luciferase reporter assay. Empty plasmid pcDNA3.1(+) containing HepG2-3.1 cells were used as control. RESULTS: (i) With the treatment of TNF-alpha for 18 h, the apoptosis rates (AR) of HepG2-F and HepG2-3.1 cells were 0.41% (+/- 0.11%) and 37.43% (+/- 2.03%) respectively, while that of HepG2-C was 4.07% (+/- 0.18%). At 36 h after TNF-alpha treatment, the AR of HepG2-F and HepG2-3.1 cells were 10.03% (+/- 0.41%) and 44.63% (+/- 3.37%), and that of HepG2-C was 14.95% (+/- 0.85%). (ii) After the treatment of TNF-alpha for 0.5-18 h, the p65 contents in the whole cells of HepG2-F and HepG2-3.1 showed no significant difference (P = 0.34, t = 1.08), while the p65 contents in the nucleus of HepG2-F and HepG2-3.1 cells were 3.8-1.9 times and 1.8-1.0 times higher than that in the non-treated cells (P = 0.013, t = 4.25). (iii) The relative luciferase unit (RLU) of the HepG2 cells, co-transfected with pcDNA3.1-F and pNF-kappaB-luc, and then treated with TNF-alpha (100 IU/mL) for 18 h, showed a pcDNA3.1-F dose-dependent increase. CONCLUSION: HCV F protein can over-activate NF-kappaB signal pathway, which makes HepG2-F cells able to resist TNF-alpha induced apoptosis.

Efficient induction of mouse immune responses to hepatitis C virus by viral core protein-carrying attenuated Salmonella typhimurium.

Hepatitis C virus (HCV) core protein is considered to be an attractive candidate for inclusion in a protective vaccine. However, this protein may attenuate the development of systemic immune responses because of its immunomodulatory properties. In this study, a eukaryotic expression plasmid, pCI-C, and an in vivo-inducible prokaryotic expression plasmid, pZW-C, for HCV core protein were constructed and transformed into attenuated Salmonella typhimurium aroA strain SL7207. The recombinant expression plasmids SL7207/pCI-C and SL7207/pZW-C were used to orally immunize BALB/c mice, and immune responses specific to core protein were assessed. Immunization with bacteria SL7207/pCI-C led to a persistent decrease in the percentage of CD3(+)CD4(+) T cells and triggered weak anti-core IgG production. Splenocytes from SL7207/pCIC-immunized mice developed relatively weak proliferation response, low interferon-gamma secretion, and inferior cytotoxic activity compared with those from mice immunized with SL7207/pZW-C. Boost immunization with SL7207/pCI-C yielded limited improvement in the immune response, whereas boost with bacteria SL7207/pZW-C enhanced immune responses significantly. These results suggest that de novo host synthesis of native HCV core protein may cut down the induction of immune responses. Attenuated S. typhimurium carrying HCV core protein could efficiently activate systemic cellular and humoral responses, and may be a promising strategy for the development of core-based HCV vaccines.

Hepatitis C virus F protein up-regulates c-myc and down-regulates p53 in human hepatoma HepG2 cells.

OBJECTIVES: Hepatitis C virus (HCV) F protein is a newly identified protein encoded by an alternative open reading frame that +1 overlaps core-encoding gene. It has been found that regulation of c-myc and p53 genes by HCV core protein is involved in liver cancer genesis. We wondered whether HCV F protein exerts similar or adverse regulatory effects on the transcription of c-myc and p53 genes. METHODS: HCV F gene-containing, plasmid pcDNA3.1-F and HCV core gene-containing pcDNA3.1-C were constructed and transiently transfected into HepG(2) cells. Real-time quantitative PCR or Western blotting was used to determine the changes at transcription or translation levels of c-myc and p53 genes. RESULTS: The transcription level of c-myc was much higher in pcDNA3.1-F transfected cells than those without plasmid transfected. Whereas the level of p53 transcription in pcDNA3.1-F transfected cells was lower than those in the parental cells. Moreover, levels of c-myc expression were up-regulated and those of p53 expression were down-regulated by HCV F protein. CONCLUSIONS: HCV F protein is of regulatory properties in cellular oncogene c-myc and anti-oncogene p53, which may be implicated in the formation of hepatocellular carcinoma.

Up-regulation of ERK and p38 MAPK signaling pathways by hepatitis C virus E2 envelope protein in human T lymphoma cell line.

Hepatitis C virus (HCV) infection correlates with human immune disorders characterized by abnormal activation and proliferation of lymphocytes. Interaction of HCV major envelope protein E2 with susceptible cells occurs at an early stage of the viral infection. HCV tropism for susceptible cells may elicit cellular signaling events implicated in the viral pathogenicity, and E2 protein is known to be responsible for the tropism. We documented previously that HCV E2 protein was capable of activating extracellular signal-regulated kinase (ERK) in human hepatoma Huh-7 cells. Here, ERK and p38 mitogen-activated protein kinase (MAPK) signaling pathways were investigated in human T lymphoma cell line Molt-4 in response to HCV E2 protein. Binding of HCV E2 protein to Molt-4 cells was detectable, and such interaction was a determinant for recognition and delivery of the E2 signal to intracellular pathways. Activation of ERK and p38 MAPK was specifically induced following the HCV E2-cell interaction. CD81 and low-density lipoprotein receptor (LDLR), proposed cellular receptors for HCV, were expressed naturally on Molt-4 cells. CD81 and LDLR were shown to mediate HCV E2-induced activation of ERK and p38 MAPK. In CD81-deficient U937 cells, levels of ERK and p38 MAPK activation and cell proliferation induced by HCV E2 protein were lower than those in Molt-4 cells. Furthermore, cell proliferation and secretion of interferon-gamma and interleukin-10 by Molt-4 cells were promoted by HCV E2 protein. Therefore, ERK and p38 MAPK signaling pathways were up-regulated by HCV E2 protein without synergetic stimulation, which was accompanied by alterations of cell behavior.

[Impact evaluation of universal salt iodization on spectrum of thyroid diseases in Changzhou area, Jiangsu, China].

OBJECTIVE: To evaluate the impact of universal salt iodization using monitoring data on correctional status of iodine deficiency and hospitalized thyroid diseases. METHODS: Retrospective survey was conducted to collect medical records of hospitalized thyroid disease cases. Routine monitoring data on population iodine nutrition status and goiter prevalence were analyzed. RESULTS: The coverage of adequately iodized salt was consistently above 95%. Hospitalization rate of thyroid diseases rose steadily, and peaked at 54.5 per 100,000. The proportion of hospitalized thyroid disease among hospitalized diseases also rose with female and those aged above 40 years old mostly affected. The proportion of hospitalized hyperthyroidism among total hospitalized thyroid disease rose from 13.6% to 34.7%. CONCLUSIONS: Universal salt iodization might eliminate iodine deficiency while other impact still exists. However, the benefits of universal salt iodization should be far overweight the adverse effects.

[Screening and real-time quantitative detection for genomic signatures of Bacillus anthracis].

A total amount of 117 candidate chromosomal sequences were screened for the genomic signatures of Bacillus anthracis by a 2-step approach. Out of them, 19 genomic signatures sequences were selected, among which, 6 genomic signatures were competent as the target sequence of TaqMan real-time PCR method. With the most significant alignment and specificity, fragment C04, together with pagA gene and capB gene from virulence plasmids pX01 and pX02, was selected to establish a TaqMan real-time PCR assay. For each target sequence, as little as 10 to 100 copies per reaction could be detected. Twelve bacterial species including 7 from Bacillus cereus group which were closely related to Bacillus anthracis were used to test the specificity of this assay. Data revealed that the assay gained a 100% specificity. Further performance of the assay was assessed with 10 simulative contaminated environmental samples and 20 negative control environmental samples; all of the Bacillus anthracis contaminated samples gave strong positive signals while the control samples were negative. This specific and sensitive real-time PCR assay could be used in rapid confirmation or exclusion of potential bio-attacks and the diagnosis of anthrax.

A Schisandra-Derived Compound Schizandronic Acid Inhibits Entry of Pan-HCV Genotypes into Human Hepatocytes.

Despite recent progress in the development of hepatitis C virus (HCV) inhibitors, cost-effective antiviral drugs, especially among the patients receiving liver transplantations, are still awaited. Schisandra is a traditional medicinal herb used to treat a range of liver disorders including hepatitis for thousands of years in China. To isolate the bioactive compounds of schisandra for the treatment of HCV infection, we screened a schisandra-extracts library and identified a tetracyclic triterpenoid, schizandronic acid (SZA), as a novel HCV entry inhibitor. Our findings suggested that SZA potently inhibited pan-HCV genotype entry into hepatoma cells and primary human hepatocytes without interfering virus binding on cell surface or internalization. However, virion-cell fusion process was impaired in the presence of SZA, along with the increased host membrane fluidity. We also found that SZA inhibited the spread of HCV to the neighboring cells, and combinations of SZA with interferon or telaprevir resulted in additive synergistic effect against HCV. Additionally, SZA diminished the establishment of HCV infection in vivo. The SZA target is different from conventional direct-acting antiviral agents, therefore, SZA is a potential therapeutic compound for the development of effective HCV entry inhibitors, especially for patients who need to prevent HCV reinfection during the course of liver transplantations.

Anchoring of both PKA-RIIα and 14-3-3θ regulates retinoic acid induced 16 mediated phosphorylation of heat shock protein 70.

Our previous study reported that retinoic acid induced 16 (RAI16) could enhance tumorigenesis in hepatocellular carcinoma (HCC). However, the cellular functions of RAI16 are still unclear. In this study, by immunoprecipitation and tandem (MS/MS) mass spectrometry analysis, we identified that RAI16 interacted with the type II regulatory subunit of PKA (PKA-RIIα), acting as a novel protein kinase A anchoring protein (AKAP). In addition, RAI16 also interacted with heat shock protein 70 (HSP70) and 14-3-3θ. Further studies indicated that RAI16 mediated PKA phosphorylation of HSP70 at serine 486, resulting in anti-apoptosis events. RAI16 was also phosphorylated by the anchored PKA at serine 325, which promoted the recruitment of 14-3-3θ, which, in turn, inhibited RAI16 mediated PKA phosphorylation of HSP70. These findings offer mechanism insight into RAI16 mediated anti-apoptosis signaling in HCC.

[Survey on status of staff for Plasmodium microscopy examinations in Changzhou City].

OBJECTIVE: To understand the current state of staff for Plasmodium microscopy examinations in Changzhou City in the early stage of eliminating malaria action, so as to provide the evidence for achieving the target of malaria elimination. METHODS: The staff for Plasmodium microscopy examinations from medical institutions and centers for disease control and prevention at different levels were investigated by questionnaires and tests of the malaria related theory and microscopic operation. RESULTS: Totally 95 people were investigated, and among them, 40.0% had college degree and 45.3% were university educated. There were 18.9% of them working on Plasmodium microscopy examinations for less than 1 year, 40.0% for 2-5 years, 18.9% for 6-10 years and 22.1% for more than 10 years. The numbers of person-time of provincial and municipal level training, district-level training, and unit-level training in the last year were 0.57, 0.59, and 0.14, respectively. Totally 18.9% of them had the experience of finding Plasmodium at work, and 97.9% of them considered it was necessary or very necessary to do Plasmodium microscopy examinations. However, 57.9% and 8.4% of them considered Plasmodium microscopy examinations increased their work load and work difficulty, respectively. The average correct rates of knowledge tests on malaria before and after training were 72.5% and 91.6% respectively (P < 0.05). The average mark of Plasmodium microscopic tests was 25.3 points (full mark being 50 points), and the passing rate (> or = 30 points) was 58.9%. CONCLUSION: The working experience of staff for Plasmodium microscopy examinations in Changzhou City is relatively poor, and the related training should be enhanced.

Activation of p38 MAPK pathway by hepatitis C virus E2 in cells transiently expressing DC-SIGN.

Dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin (DC-SIGN) is a cellular receptor for hepatitis C virus for the binding of viral envelope glycoprotein E2. Interaction of DC-SIGN with the E2 may evoke cellular signal transduction implicated in viral pathogenesis. We developed a cell model with DC-SIGN transient transfection to study p38 mitogen-activated protein kinase (MAPK) signaling pathway in response to the E2 treatment. HEK293T and HeLa were DC-SIGN-deficient cell lines. DC-SIGN was detectable at the surface of HEK293T and HeLa transfected with DC-SIGN, and the levels of DC-SIGN were high in transfected-HEK293T as compared with HeLa. The transfected-HEK293T displayed ability for the E2 binding. In the transfected-HEK293T, level of p38 MAPK phosphorylation was increased upon the E2 treatment and reduced following blockage of DC-SIGN with an antibody against DC-SIGN. Phosphorylation of downstream transcription factor activating transcription factor (ATF)-2 was also up-regulated by the E2 via DC-SIGN. Similar results were obtained with NIH3T3 cells stably expressing DC-SIGN and Huh7 cells. Our results indicate that DC-SIGN transient expression in HEK293T is a useful cell model for investigating p38 MAPK pathway triggered by the E2, which may provide information for understanding cellular receptors-mediated signaling events and the viral pathogenesis.

Proteomic analysis of differently expressed proteins in human hepatocellular carcinoma cell lines HepG2 with transfecting hepatitis B virus X gene.

BACKGROUND: Hepatitis B virus encoded X protein (HBx) is a trans-activating protein that may be involved in hepatocarcinogenesis, although few natural effectors of HBx that participate in this process have been identified. We screened, by comparative proteomics method, effectors of HBx associated with hepatocarcinogenesis. METHODS: HBx positive and negative HepG2 cells were constructed and expression patterns of cellular proteins were obtained by high resolution, two dimensional electrophoresis. Comprehensive analyses of proteins associated with hepatocellular carcinoma (HCC) were focused on the differently expressed proteins (more than two-fold increase or decrease, P < 0.05) from HBx positive and negative HepG2 cells. For peptide mass fingerprinting, protein spots with different intensity between HBx positive and negative HepG2 cells were directly cut out of gels and processed for matrix assisted, laser desorption/ionization, time of flight mass spectrometry and liquid chromatography-tandem mass spectrometry (LC-ESI-MS/MS) analysis. RESULTS: The mean number of protein spots for HBx negative and HBx positive HepG2 cells were 2095 +/- 137 and 2188 +/- 105, respectively. The analysis of paired cells showed 75 spots with significant differences in expression between HBx negative and HBx positive cells: 37 spots corresponding to 32 different proteins; 25 proteins were upregulated, 7 downregulated. We found 7 proteins not previously reported differentially expressed in HBx positive HepG2 cells. Variations in protein accumulation were confirmed for four (HSP90AB1, BCL2 associated athanogene 2, nucleophosmin and chloride intracellular channel 1) by Western blotting in HBx positive HepG2 cells. CONCLUSIONS: Numerous effectors of HBx that may promote the development of HCC are identified, of which 7 are newly noted in HepG2 cells. Several of these effectors of HBx may help in elucidating the roles of HBx in hepatocarcinogenesis and diagnostics or targets for therapeutic intervention.

Isoform of vascular endothelial cell growth inhibitor (VEGI72-251) increases interleukin-2 production by activation of T lymphocytes.

The objective of this study is to investigate the characteristics of the recombinant variant of human vascular endothelial cell growth inhibitor, VEGI72-251, and compare its biological activities with that of its prototype VEGI24-174. The recombinant plasmid containing the variant VEGI72-251 gene was constructed and expressed in Escherichia coli. The effects of the expressed VEGI72-251 on cell proliferations were checked in the human umbilical vein endothelial cell line and certain tumor cell lines (ECV304 and B16). The inhibition of VEGI72-251 on angiogenesis was detected in the chorioallantoic membrane of chick embryos. In comparison with VEGI24-174, the recombinant human VEGI72-251 seems to have no effect on the proliferation of endothelial cells and the angiogenesis of the chorioallantoic membrane in vitro. An enzyme-linked immunosorbent assay-based method was used for the measurement of interleukin-2 (IL-2) production by peripheral blood monocytes (PBMCs) treated with VEGI72-251. PBMCs were pretreated with VEGI72-251 (1.25-12.50 microg/ml) for 24 h in vitro, and the IL-2 concentration in PBMC medium was increased from 354 pg/ml to 1256 pg/ml. It can be concluded that VEGI72-251 is able to increase the level of human IL-2 production by the activation of T lymphocytes. Differing from VEGI24-174 on anti-angiogenesis, VEGI72-251 may serve as an anti-cancer factor through its activation of T lymphocytes.

[Rapid detection of Pseudomonas aeruginosa by the fluorescence quantitative PCR assay targeting 16S rDNA].

The 16S rDNA specific primers were designed for rapid detection of Pseudomonas aeruginosa (PA) by the fluorescence quantitative PCR (FQ-PCR) assay, based upon multiple sequence alignment and phylogenetic tree analysis of the 16S rDNAs of over 20 bacteria. After extraction of PA genomic DNA, the target 16S rDNA fragment was amplified by PCR with specific primers, and used to construct recombinant pMDT-Pfr plasmid, the dilution gradients of which were subjected to the standard quantitation curve in FQ-PCR assay. Different concentrations of PA genomic DNA were detected by FQ-PCR in a 20microL of reaction system with SYBR Green I. At the same time, various genomic DNAs of Staphylococcus aureus, Salmonella typhi, Shigella flexneri, Proteus vulgaris, Staphylococcus epidermidis, Escherichia coli, and Mycobacterium tuberculosis were used as negative controls to confirm specificity of the FQ-PCR detection assay. Results demonstrated that the predicted amplified product of designed primers was of high homology only with PA 16S rDNA, and that sensitivity of the FQ-PCR assay was of 3.6pg/microL of bacterial DNA or (2.1 x 10(3) +/- 3.1 x 10(2)) copies/microL of 16S rDNA, accompanied with high specificity, and that the whole detection process including DNA extraction could be completed in about two hours. In contrast to traditional culture method, the FQ-PCR assay targeting 16S rDNA gene can be used to detect PA rapidly, which exhibits perfect application prospect in future.

DNA vaccine of SARS-Cov S gene induces antibody response in mice.

The spike (S) protein, a main surface antigen of SARS-coronavirus (SARS-CoV), is one of the most important antigen candidates for vaccine design. In the present study, three fragments of the truncated S protein were expressed in E.coli, and analyzed with pooled sera of convalescence phase of SARS patients. The full length S gene DNA vaccine was constructed and used to immunize BALB/c mice. The mouse serum IgG antibody against SARS-CoV was measured by ELISA with E. coli expressed truncated S protein or SARS-CoV lysate as diagnostic antigen. The results showed that all the three fragments of S protein expressed by E.coli was able to react with sera of SARS patients and the S gene DNA candidate vaccine could induce the production of specific IgG antibody against SARS-CoV efficiently in mice with seroconversion ratio of 75% after 3 times of immunization. These findings lay some foundations for further understanding the immunology of SARS-CoV and developing SARS vaccines.