Project description:Chronic hepatitis C virus (HCV) infection is a leading cause of liver cancer. HCV propagation and oncogenicity depend in part on the phosphorylation states of its non-structural protein 5A (NS5A); however, little is known about how hypo- or hyper-phosphorylated NS5A functions. Here, we segregated hypo- from hyper-phosphorylated NS5A in HCV-infected Huh7.5.1 cells with two custom-made specific antibodies and differentiated their interacting proteins with dimethyl labeling-based quantitative proteomics. Bioinformatics analysis revealed that hyper-phosphorylated NS5A preferentially binds the polymerase II-associated factor 1 complex known to alter host gene expression involved in cancer progression. In contrast, hypo-phosphorylated NS5A binds proteins involved in host antiviral response. Moreover, we found that the hypo-phosphorylated NS5A binds DNA-dependent protein kinase catalytic subunit (DNA-PKcs) predicted to phosphorylate NS5A at serine 232, a key amino acid that governs NS5A transition from hypo- to hyper-phosphorylation state. Inhibition of DNA-PKcs with an inhibitor or via gene-specific knockdown significantly reduced serine 232 phosphorylation and NS5A hyper-phosphorylation. Collectively, we have identified a protein kinase that regulates a delicate balance of NS5A between hypo- and hyper-phosphorylation states respectively involved in host antiviral responses and liver cancer progression.
Project description:Numerous mammalian proto-oncogene and other growth-regulatory transcripts are upregulated in malignancy due to abnormal mRNA stabilization. In hepatoma cells expressing a hepatitis C virus (HCV) subgenomic replicon, we found that the viral nonstructural protein 5A (NS5A), a protein known to bind to viral RNA, also bound specifically to human cellular transcripts that encode regulators of cell growth and apoptosis, and this binding correlated with transcript stabilization. An important subset of human NS5A-target transcripts contained GU-rich elements, sequences known to destabilize mRNA. We found that NS5A bound to GU-rich elements in vitro and in cells. Mutation of the NS5A zinc finger abrogated its GU-rich element-binding and mRNA stabilizing activities. Overall, we identified a molecular mechanism whereby HCV manipulates host gene expression by stabilizing host transcripts in a manner that would promote growth and prevent death of virus-infected cells, allowing the virus to establish chronic infection and lead to the development of hepatocellular carcinoma.
Project description:We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process. Goal and objectives: To study the requirement of HCV viral proteins and/or environmental factors (such as alcohol or obesity) in synergistic liver caner development in HCV Core or NS5A Tg mice given alcohol or high-cholesterol high-fat diet, mice were fed alcohol or high-cholesterol high-fat diet and liver tissues from these mice were examined for gene profiles. Alcohol or obesity contributes to synergistic tumor incidence and HCV Core or Ns5a-induced effects. Thus, analysis of gene profiling of these transgenic mice will identify the critical pathways to induce synergistic tumor formation caused by alcohol or obesity.
Project description:We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process. Goal and objectives: To study the requirement of HCV viral proteins and/or environmental factors (such as alcohol or obesity) in synergistic liver caner development in HCV Core or NS5A Tg mice given alcohol or high-cholesterol high-fat diet, mice were fed alcohol or high-cholesterol high-fat diet and liver tissues from these mice were examined for gene profiles. Alcohol or obesity contributes to synergistic tumor incidence and HCV Core or Ns5a-induced effects. Thus, analysis of gene profiling of these transgenic mice will identify the critical pathways to induce synergistic tumor formation caused by alcohol or obesity. Liver samples for RNA extraction and hybridization on Affymetrix microarrays. We sought to obtain gene profiling data in order to increase understanding the pathways. To perform gene array and proteomic analyses, mice were fed alcohol or high-cholesterol high-fat for 12 months and euthanized after 12 months feeding. Livers were collected at the time of euthanasia.
Project description:Hepatitis C Virus protein NS5A was found to upregulate assembly of cap binding initiation complex eIF4F in Huh7.5 cells. NS5A also was found to associate with translation machinery. To understand consequences of NS5A mediation in host translation, we analyzed mRNA associated with polysome fractions of NS5A expressing Huh7.5 cells and compared them with the corresponding fractions from control cells.
Project description:Hepatitis C Virus protein NS5A was found to upregulate assembly of cap binding initiation complex eIF4F in Huh7.5 cells. NS5A also was found to associate with translation machinery. To understand consequences of NS5A mediation in host translation, we analyzed mRNA associated with polysome fractions of NS5A expressing Huh7.5 cells and compared them with the corresponding fractions from control cells. Agilent-027114 Genotypic Technology designed Custom Human Whole Genome 8x60k Microarray
Project description:We performed miRNA array analysis for S-HCV (short-term HCV), L-HCV (long-term HCV) and control (uninfected Huh751), total for 3 samples to identify miRNA candidates in HCV-related HCC.
Project description:In order to infer the inverse expression relationships between microRNAs and mRNAs during HCV infection, we profiled both microRNA and mRNA expressions in HCV positive (HCV+) and HCV negative (HCV-) human liver biopsy tissue samples. This series includes all microRNA profiles.