No description available.

Hepatitis B virus (HBV) is a major etiologic agent of chronic liver disease (CLD) and hepatocellular carcinoma (HCC). The virally encoded X antigen, HBx, contributes importantly to the development of HCC through its trans-activating role in various signal transduction pathways. Pathways implicated in stem cell self-renewal also contribute to carcinogenesis. Thus, experiments were designed to test if HBx triggers malignant transformation by promoting properties that are characteristic of cancer stem cells (CSCs). To test this hypothesis, HBx expressing (HepG2X) and control (HepG2CAT) human cell lines were assayed for phenotypic and molecular characteristics of "stemness." Western blotting of protein extracts from HepG2X and HepG2CAT cells as well as immunohistochemical staining of HCC and adjacent liver tissue sections from HBV infected patients showed up-regulation of "stemness"-associated (EpCAM and beta-catenin) and "stemness" (Oct-4, Nanog, Klf-4) markers by HBx. Moreover, HBx stimulated cell migration and spheroid formation. HBx expression was also associated with depressed levels of E-cadherin and subsequent activation of beta-catenin and EpCAM. Results from ChIP-chip data performed previously in this lab suggest an associative link between HBx and the expression of epigenetic co-repressor, mSin3A, which is known to repress E-cadherin when complexed with histone deacetylases. Thus, experiments were also designed to test if HBx represses the E-cadherin gene (CDH1) through histone deacetylation by the mSin3A/HDAC complex. In HepG2X cells, decreased levels of E-cadherin and elevated levels of mSin3A were detected. Reciprocal immunoprecipitation with anti-HBx and anti-mSin3A demonstrated mutual binding. Further, HBx-mSin3A co-localization was showed by immunofluorescent staining. Chromatin immunoprecipitation revealed that HBx mediated the recruitment of the mSin3A/HDAC complex to the CDH1 promoter. HDAC inhibition by Trichostatin A treatment restored E-cadherin expression. Thus, HBx-associated epigenetic repression of E-cadherin and up-regulated expression of multiple "stemness" markers support the hypothesis that HBx contributes to hepatocarcinogenesis, at least in part, by promoting changes in gene expression that are characteristic of CSCs. This work is the first to propose that HBV promotes "stemness" in the pathogenesis of HCC. / Biology

Chronic infection with hepatitis B virus (HBV) is a primary risk factor for the development of hepatocellular carcinoma (HCC). HCC is the fifth most common cancer type worldwide with few treatment options. The hepatitis B encoded x antigen (HBx) plays a crucial role in the pathogenesis of HCC through several mechanisms. HBx alters signaling pathways shown to promote carcinogenesis and mediates epigenetic changes that silence tumor suppressor genes and activate host oncogenes. Short chain fatty acids (SCFAs) are made by selected gut bacteria with largely anti-inflammatory properties. They alter gene expression by functioning as histone deacetylase inhibitors (HDACi) and can bind to G protein coupled receptors (GCPR) to stimulate signaling pathways. Due to the documented anti-cancer properties of SCFAs, experiments were designed to test the hypothesis that SCFAs delay the development of HCC in HBx transgenic (HBxTg) mice. A diet of SCFAs was fed to HBxTg for three months prior to the expected appearance of dysplastic nodules and HCC. The results showed a statistically significant reduction in the number of dysplastic nodules as well as the presence and frequency of HCC. The effect of SCFAs on tumor growth was also evaluated in nude mice subcutaneously injected with human HCC cells. Tumor size in SCFA-treated mice was statistically smaller compared to the controls. The effect of SCFAs on cell viability of cancer and primary human hepatocytes was evaluated. SCFAs were shown to reduce cell viability in cancer cells only, with no effect on primary hepatocytes. Proteomics was performed on SCFA-treated compared to control livers from HBxTg to investigate changes on the molecular level that are associated with reduced preneoplastic and neoplastic nodule formation. Pathway analysis showed a decrease in important cancer-promoting pathways altered by HBx in HCC, including inflammation, oxidative stress, PI3K, VEGF, EGF, and Ras. These pathways are involved in biological processes central to carcinogenesis such as cell proliferation, survival, and angiogenesis. The ability of SCFAs to decrease these pathways has never been demonstrated. Further investigation confirmed that Ras activity was decreased in 12-month old livers treated with SCFAs. Taken together, these results show that SCFAs are capable of delaying the rate of tumor growth and tumor frequency in two mouse models of HBV-associated HCC, as well as reduce cell viability in cancer cells specifically. This data suggests that SCFAs may be a novel treatment option for HBV-associated HCC. / Biology

Porcine epidemic diarrhea Virus (PEDV) is a virus effecting swine. It is the cause of disease that manifests with symptoms ranging from depression, to severe dehydration and death. Young piglets are particularly susceptible to the virus, which can reach mortality rates of 100%. Presence of the virus on a swine farm can therefore cause severe economic losses. Treatments currently exist for PEDV, but are mostly generated from the virus itself. There has recently been renewed interest in a vaccine that is made from a different source, which might help eliminate some of the side effects of those that currently exist on the market. This project outlines three experiments performed in animals. During the first experiment, a structural protein from the Hepatitis B virus was genetically altered to include important structural portions of PEDV. This new protein is generated in E. coli and purified. After purification, the protein assembles into a virus-like particle (VLP). VLPs are structural proteins of existing viruses that are expressed and assembled to mimic the virus. By doing so, the immune system recognizes the protein as a potential threat, and launches a response in the form of antibodies. Manipulations of the VLPs as describe herein allow the new vaccine to generate antibodies toward other diseases such as PEDV. Although all five of the vaccines used in the first experiment were able to generate appropriate antibodies, only two of them were effective at preventing PEDV from entering susceptible cells (virus neutralization). A second experiment, with three newly designed vaccines was therefore performed. This experiment, like the first, was successful in producing antibodies to several of the included PEDV protein sections, but none were able to neutralize the virus. These results led to a third experiment, during which further design improvements were made to the basic vaccine structure in an attempt to increase the neutralization capabilities of the vaccines. The results from the third experiment indicated that several changes to the vaccine increased the immune response to the structural portions of PEDV, providing a better overall vaccine candidate. This also led to the conclusion that one specific sequence from PEDV has a better ability to neutralize the virus than the other sections. / PHD / Porcine epidemic diarrhea Virus (PEDV) is a virus effecting swine. It is the cause of disease that manifests with symptoms ranging from depression, to severe dehydration and death. Young piglets are particularly susceptible to the virus, which can reach mortality rates of 100%. Presence of the virus on a swine farm can therefore cause severe economic losses. Treatments currently exist for PEDV, but are mostly generated from the virus itself. There has recently been renewed interest in a vaccine that is made from a different source, which might help eliminate some of the side effects of those that currently exist on the market. This project outlines three experiments performed in animals. During the first experiment, a structural protein from the Hepatitis B virus was genetically altered to include important structural portions of PEDV. This new protein is generated in E. coli and purified. After purification, the protein assembles into a virus-like particle (VLP). VLPs are structural proteins of existing viruses that are expressed and assembled to mimic the virus. By doing so, the immune system recognizes the protein as a potential threat, and launches a response in the form of antibodies. Manipulations of the VLPs as describe herein allow the new vaccine to generate antibodies toward other diseases such as PEDV. Although all five of the vaccines used in the first experiment were able to generate appropriate antibodies, only two of them were effective at preventing PEDV from entering susceptible cells (virus neutralization). A second experiment, with three newly designed vaccines was therefore performed. This experiment, like the first, was successful in producing antibodies to several of the included PEDV protein sections, but none were able to neutralize the virus. These results led to a third experiment, during which further design improvements were made to the basic vaccine structure in an attempt to increase the neutralization capabilities of the vaccines. The results from the third experiment indicated that several changes to the vaccine increased the immune response to the structural portions of PEDV, providing a better overall vaccine candidate. This also led to the conclusion that one specific sequence from PEDV has a better ability to neutralize the virus than the other sections.

Yes / Coronavirus is the most dangerous virus in the world wide and it can easy spread between people, animals and plants because it is existing on one strand of RNA (Ribonucleic Acid) and it can duplicate faster than any virus. The source of coronavirus is still unknown, but some sources said that it came from seafood market and other sources said that it came from bat and snakes. It starts in Wuhan; China and every day the fatality increases. The symptoms are like a SARS-CoV (acute respiratory syndrome coronavirus)) and MERS-CoV (Middle East Respiratory Syndrome Coronavirus). By using nucleotide sequence of coronavirus from NCBI (National Center for Biotechnology Information) and some programs that ran on Matlab, the results show that there are some differences and similarities between coronavirus and other viruses such as Ebola, Flu-b, Hepatitis B, HIV and Zika especially for DEBs (distinct excluded blocks) program that shows at 5bp (base pair) there is a common with slightly difference between coronavirus “cgggg” and Ebola virus “cgtgg”. The aim from this study is to find a way to help doctors and scientists to stop spreading the coronavirus or to destroy it.

No description available.

[Truncated abstract] Around 50,000 hip and knee replacements are performed every year in Australia and this number has been increasing by around 13% annually since 1998 (Transplantation Society 2006). The incidence and number of revision surgery has increased by a similar proportion. Autogenous bone or allograft is still the gold standard grafting material and is currently used in a variety of reconstructive surgical procedures. The use of any allograft material carries with it the risk of transfer of disease from donor to recipient. These tissues can transmit the same viral and bacterial infections as blood, and the products of a single donation may be transplanted to several recipients. In contrast to blood, musculoskeletal tissues may come from surgical and cadaveric donation. Overall, the prevention of infection relies on the maintenance of rigid protocols for procurement, donor and allograft testing, secondary sterilisation, and the adherence to internal safety standards within the tissue banks. This thesis aims to determine the risk of viral infection among musculoskeletal tissue donors in Australia. We retrieved and analysed data retrospectively from three large tissue banks in Australia (Perth, Queensland, Victoria). This includes 12,415 musculoskeletal tissue donors, 10,937 of which are surgical donors and 1,478 of which are deceased donors, for the period of 1993 -2004. This data was analysed to determine the prevalence and incidence of viral infections such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) and human T-lymphotropic virus (HTLV) in musculoskeletal allografts. The results indicate that the risk of viral infection from musculoskeletal tissue transplantation in Australia is low. ... The results indicate that the overall prevalence of screened transfusion-transmitted viral infections did not vary significantly for musculoskeletal donors over the study period, despite falling in the general population and first-time blood donors. In tissue donors, HIV incidence significantly decreased over time, and HBV decreased significantly during 1999-2001; however, there was an apparent increase in the estimated incidence of HCV in 2002-2004 compared with earlier years. Furthermore the residual risk estimate of HIV in the period 2002-2004 has declined 5-fold compared to estimates in the period 1993-1995. This is perhaps due to greater awareness of high risk behaviours among donors, improvement in donor recruitment and an overall decrease in infection levels in the general population. Musculoskeletal tissue is second only to blood as the most frequent transplanted human tissue. Viral infection is a potential complication of tissue transplantation. In this thesis the rates of HIV, HBV, HCV and HTV infection in musculoskeletal donors in Australia were identified and then compared with results in published data from Canada, Scotland and the United States. The study also compared that result with first-time blood donors because they have satisfied similar donor selection criteria (Galea et al. 2006). The results indicate that prevalence and incidence estimates for viral infection in Australian tissue donors are higher than those in blood donors. This was also reported in studies from other countries. Accordingly, it is crucial that viral prevalence and incidence be monitored to evaluate the safety of tissue supply and to improve donor selection processes.

published_or_final_version / Psychology / Doctoral / Doctor of Philosophy

Dans les pays d’Afrique Sub-Saharienne et d’Asie du Sud-Est, l’infection chronique par le virus de l’hépatite B (VHB) et l’exposition à l’aflatoxine B1 (AFB1) ont un rôle synergique dans le développement du carcinome hépatocellulaire (CHC). Cependant les mécanismes impliqués ne sont pas élucidés à ce jour. Le VHB est un petit virus à ADN qui induit différentes maladies du foie allant du portage asymptomatique au CHC. L’AFB1 est une mycotoxine qui contamine la nourriture. Après activation en époxyde, elle forme des adduits à l’ADN puis des mutations, dont la mutation au codon 249 du gène suppresseur de tumeur TP53 (AGG → AGT, mutation R249S). Nous avons utilisé les caractéristiques uniques de la lignée cellulaire HepaRG pour étudier les interactions entre le VHB et l’AFB1 : ces cellules se différencient in vitro en hépatocytes qui métabolisent l’AFB1 et peuvent être infectés par le VHB. Nous avons montré que l’AFB1 induit une réponse de p53 dose-dépendante et agit comme un agent antiviral en réprimant la production de particules virales après 48h d’exposition. D’autre part, l’infection par le VHB n’a montré aucun effet sur la formation ou la réparation des adduits. De la réparation et de la prolifération cellulaire ont été observées suite au traitement à l’AFB1, suggérant la faisabilité de l’étude de mutations dans ce système, dont R249S. Ces résultats suggèrent que l’AFB1 atténue l’hépatite chronique tout en maintenant les hépatocytes sous intense pression mutagène, ce qui favoriserait la progression vers le CHC / In sub-Saharan Africa and South-East Asia, chronic infection by hepatitis B virus (HBV) and exposure to aflatoxin B1 (AFB1) play a synergic role in the development of hepatocellular carcinoma (HCC). However mechanisms are still largely unknown. HBV is a small DNA virus which induces different liver diseases from asymptomatic carriage to HCC. AFB1 is a mycotoxin which contaminates food. After activation into an epoxide, it forms DNA adducts and mutations, such as R249S mutation at codon 249 in tumor suppressor TP53 gene (AGG → AGT). We have taken advantage of the unique features of the cell line HepaRG to investigate interactions between both risk factors: cells differentiate in vitro into hepatocytes which metabolize AFB1 and can be infected by HBV. We have shown that AFB1 induces a dose-dependent p53 response and act as an antiviral agent by repressing production of HBV particles after 48 hours of exposure. Nevertheless HBV infection had no effect on adduct formation or repair. Moreover DNA synthesis activity associated to DNA repair and cell proliferation were observed following AFB1 treatment, suggesting the feasibility of mutation research in this model, especially R249S. Overall these results suggest that AFB1 may attenuate HBV chronic hepatitis while maintaining hepatocytes under intense mutagenic pressure, thus enhancing the progression towards HCC

by Shuk-kei Lau. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 141-148). / Abstracts in English and Chinese. / Acknowledgement --- p.i / Table of Contents --- p.ii / Abstract --- p.vi / 論文摘要 --- p.viii / Abbreviations --- p.ix / List of Figures --- p.x / List of Tables --- p.xii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- General introduction --- p.1 / Chapter 1.2 --- HBV and its role in hepatocarcinogenesis --- p.3 / Chapter 1.2.1 --- Current situation of HBV infection and the HCC incidencein the world --- p.3 / Chapter 1.2.2 --- Current situation of HBV infection and the HCC incidencein Hong Kong --- p.4 / Chapter 1.2.3 --- Genetic organization of HBV --- p.4 / Chapter 1.2.4 --- Principle of hepatocarcinogenesis induced by HBV --- p.5 / Chapter 1.2.4.1 --- Role of chronic hepatitis in hepatocarcinogenesis --- p.5 / Chapter 1.2.4.2 --- Role of HBV in hepatocarcinogenesis --- p.6 / Chapter 1.2.5 --- Current screening tests for HCC --- p.7 / Chapter 1.2.6 --- Current therapies for HCC --- p.9 / Chapter 1.3 --- Aim of the present study --- p.13 / Chapter 1.4 --- "Combining Expressed Sequence Tag (EST), Suppression Subtractive Hybridization and cDNA microarray for rapid differentially by expressed genes screening" --- p.14 / Chapter 1.4.1 --- Expressed Sequence Tag (EST) --- p.14 / Chapter 1.4.2 --- cDNA subtraction --- p.15 / Chapter 1.4.3 --- cDNA microarray --- p.16 / Chapter Chapter 2 --- Materials and Methods / Chapter 2.1 --- PCR-select cDNA subtraction --- p.17 / Chapter 2.1.1 --- Amplification of subtracted cDNA clones by PCR --- p.17 / Chapter 2.1.2 --- Cycle sequencing of subtracted cDNA clones --- p.18 / Chapter 2.1.3 --- Sequence analysis using BLAST server and Stanford Online Universal Resource for Clones and ESTs (SOURCE) --- p.19 / Chapter 2.2 --- cDNA microarray analysis --- p.20 / Chapter 2.2.1 --- Array fabrication --- p.20 / Chapter 2.2.1.1 --- Amplification of cDNA clones by PCR --- p.20 / Chapter 2.2.1.2 --- Purification of PCR products --- p.21 / Chapter 2.2.1.3 --- Cycle sequencing for clones checking --- p.22 / Chapter 2.2.2 --- Microarray printing --- p.22 / Chapter 2.2.2.1 --- Preparation of cDNA target --- p.22 / Chapter 2.2.2.2 --- Arraying --- p.22 / Chapter 2.2.3 --- Screening of differentially expressed genes in hepatocellular carcinoma and its surrounding normal counterpart by cDNA microarray --- p.23 / Chapter 2.2.3.1 --- Extraction of RNA --- p.23 / Chapter 2.2.3.2 --- RNA labeling --- p.24 / Chapter 2.2.3.3 --- Microarray hybridization --- p.26 / Chapter 2.2.3.4 --- Collection of data --- p.27 / Chapter 2.2.3.5 --- Data normalization and analysis --- p.28 / Chapter 2.3 --- Molecular cloning and characterization of a novel cDNA clone differentially expressed in HCC --- p.30 / Chapter 2.3.1 --- Tissue distribution of T2L522 gene --- p.30 / Chapter 2.3.1.1 --- Northern hybridization --- p.30 / Chapter 2.3.1.2 --- Reverse-transcriptase polymerase chain reaction (RT-PCR) --- p.33 / Chapter 2.3.2 --- Expression level of T2L522 in HCC and its surrounding normal counterpart --- p.33 / Chapter 2.3.3 --- Identification of interacting partner of T2L522 using yeast two-hybrid assay --- p.35 / Chapter 2.3.3.1 --- "Cloning of T2L522 gene into the yeast two-hybrid DNA-BD vector, pGBKT7" --- p.35 / Chapter 2.3.3.2 --- Transformation of yeast competent cells --- p.39 / Chapter 2.3.3.3 --- Mating of T2L522-BD with pretransformed human liver cDNA library --- p.40 / Chapter 2.3.3.4 --- Colony lift p-galactosidase filter assay --- p.42 / Chapter 2.3.4 --- Subcellular localization of T2L522 gene by tagging with green fluorescence protein (GFP) --- p.43 / Chapter 2.3.4.1 --- "Cloning of T2L522 gene into the eukaryotic GFP expression vector, pEGFP-Cl" --- p.43 / Chapter 2.3.4.2 --- Transfection of pEGFP-T2L522 into HepG2 cell --- p.43 / Chapter Chapter 3 --- Results / Chapter 3.1 --- PCR-select cDNA subtraction --- p.45 / Chapter 3.1.1 --- The sequencing results of subtracted-HCC cDNA clones --- p.45 / Chapter 3.1.2 --- Categorization of ESTs sequenced from subtracted-HCC library --- p.45 / Chapter 3.2 --- Microarray analysis --- p.49 / Chapter 3.2.1 --- Array fabrication --- p.49 / Chapter 3.2.1.1 --- Amplification of cDNA microarray targets --- p.49 / Chapter 3.2.2 --- Microarray printing --- p.52 / Chapter 3.2.3 --- Microarray analysis of differentially expressed genesin hepatocellular carcinoma and its surrounding normal counterpart --- p.55 / Chapter 3.2.4 --- Data collection --- p.57 / Chapter 3.2.5 --- Image processing: spots finding and quantitation --- p.61 / Chapter 3.2.6 --- Data normalization and analysis --- p.61 / Chapter 3.3 --- Molecular cloning and characterization of a novel cDNA clone differentially expressed in HCC --- p.73 / Chapter 3.3.1 --- Tissue distribution of T2L522 --- p.77 / Chapter 3.3.1.1 --- Northern hybridization --- p.77 / Chapter 3.3.1.2 --- Reverse-transcriptase polymerase chain reaction (RT-PCR) --- p.79 / Chapter 3.3.2 --- Expression level of T2L522 in hepatocellular carcinoma and its surrounding normal counterpart --- p.81 / Chapter 3.3.3 --- Identification of interacting partner of T2L522 using yeast two-hybrid assay --- p.85 / Chapter 3.3.4 --- Subcellular localization of GFP tagged T2L522 --- p.87 / Chapter Chapter 4 --- Discussion / Chapter 4.1 --- EST analysis on subtracted-HCC cDNA library --- p.89 / Chapter 4.2 --- cDNA microarray analysis --- p.92 / Chapter 4.2.1 --- Generation of reliable data using cDNA microarray --- p.92 / Chapter 4.2.1.1 --- Reproducibility of signal and normalized ratio --- p.92 / Chapter 4.2.2 --- Comparison of data between multiple slides --- p.96 / Chapter 4.2.2.1 --- Assession of data quality and statistical significance --- p.96 / Chapter 4.2.2.2 --- Interpretation of gene expression data from single and multiple hybridizarion --- p.97 / Chapter 4.3 --- Candidate genes differentially expressed in HCC and its surrounding normal counterpart --- p.99 / Chapter 4.3.1 --- Protein up-regulated in HCC --- p.99 / Chapter 4.3.1.1 --- Extracellular matrix protein --- p.99 / Chapter 4.3.1.2 --- Protein involved in other metabolism --- p.100 / Chapter 4.3.1.3 --- Protein involved in transcription and translation --- p.100 / Chapter 4.3.2 --- Protein down-regulated in HCC --- p.101 / Chapter 4.3.2.1 --- Membrane associated protein --- p.101 / Chapter 4.3.2.2 --- Protein involved in other metabolism --- p.102 / Chapter 4.3.2.2 --- Secretory protein --- p.104 / Chapter 4.3.3 --- Novel protein differentially expressed in HCC --- p.107 / Chapter 4.4 --- "TBC1 domain containing protein, T2L522" --- p.108 / Chapter 4.4.1 --- Possible involvement of T2L522 gene in HCC --- p.109 / Chapter 4.4.2 --- Tissue distribution and expression pattern of T2L522 --- p.110 / Chapter 4.4.3 --- Potential interacting partner of T2L522 --- p.110 / Chapter 4.4.4 --- Subcellular localization of T2L522 --- p.112 / Chapter 4.5 --- Summary --- p.113 / Appendix --- p.114 / References --- p.141