Impact of hepatitis c virus core genetic variability on hcv-induced hepatocellular carcinoma development, via regulation of the wnt/ b-catenin cellular pathway

• Κύριος συγγραφέας: Άιχερ, Στεφανή
• Άλλοι συγγραφείς: Πουλάς, Κωνσταντίνος
• Μορφή: Thesis
• Γλώσσα: English
• Έκδοση: 2019
• Θέματα: Hepatitis c virus; Hepatocellular carcinoma; Wnt/b-catenin; Ιός της ηπατίτιδας c; Ηπατοκυτταρικό καρκίνωμα; Wnt/β-κατενίνη; 616.362 3

Clinical studies have suggested that some hepatitis c virus (hcv) genotypes or isolates are associated with disease progression and hepatocellular carcinoma development (hcc). In addition to its known role in viral particle, hcv core protein may be directly involved in these pathogenic features affecting host’s signaling pathways. Hcv core protein was shown to interfere with host wnt/ β-cateninpathway. This work aims at investigating the role of hcv core genetic variability in the regulation of the wnt/ β-cateninpathway during hcv infection. Tcf element transactivational activity was assessed in transiently transfected cell lines expressing hcv core protein variants derived from clinical isolates of subtypes 1a, 4aR and 4fC. We demonstrated that HCV core protein up-regulates TCF element transactivation in a strain-specific manner, in transiently transfected cells, through a mechanism involving PI3K activation. Site-directed mutagenesis confirmed the role of amino acid Thr71 and Ser64 on tcf element transactivation. Genome-length recombinant chimeras were generated by exchanging the core-coding region of cell-culture adapted jfh1-derived strain with equivalent sequences from clinical isolates. After characterization of the new intergenotypic chimeric viruses high titer stocks were produced. qpcr, confocal microscopy and image analysis was performed to monitor the activation status of Wnt/ β-cateninpathway determinants during infection. In agreement, infection of hepatic cells with core-intergenotypic recombinant viruses resulted in strain-specific transcriptional up-regulation of tbx3, c-myc, axin2, fibronectin, fasn and cyclin d1 genes and nuclear translocation of β-catenin. Intergenotypic core recombinant viruses revealed a putative functional domain within region 64-71 aa of core that may interact with cellular proteins which leads to wnt/ β-cateninpathway activation. Further studies are conducted to identify this cellular target and define the molecular mechanism of core action. HCV core intergenotypic recombinants developed provide a model system to study the role of Hcv core natural mutations in the dysregulation of host pathways associated with liver disease in a relevant infection system, like primary cell lines and animal model systems. This study is expected to shed light on the molecular mechanisms underlying the association between hepatitis C virus genomic variability and hepatocellular carcinoma development.