Hepatitis C virus (HCV) infects over 150 million people worldwide. Interferon (IFN)-based therapy is the mainstay platform for treatment of HCV wherein improving IFN response rates remains paramount to achieving global sustained virological response. Genome-wide association studies (GWAS) have identified three single nucleotide polymorphisms (SNPs) near the interferon lambda 3 (IFNL3 also known as IL28B) gene that strongly associate with HCV patient response to therapy and natural clearance of infection. However, the functional polymorphism mediating these associations is still unknown. We have found that a 3'UTR polymorphism (rs4803217) dictates IFNL3 expression by altering mRNA stability through the recruitment of HCV-induced microRNAs (miRNAs) and AU-rich element (ARE)-binding proteins (ARE-BP). Our preliminary data show that expression of the rs4803217 T variant is repressed by the induced miRNAs and AU-rich element mediated decay, whereas a single T>G polymorphism rescues this suppression. This proposal aims to identify the specific ARE sequences and ARE-BP that function with miRNAs in the post-transcriptional "regulon" acting on IFNL3 variants. We will study the pathways that influence this regulon, namely the ability of HCV to induce host miRNAs in hepatocytes. Finally, we will investigate how the IFNL3 regulon affects the interferon-mediated antiviral response to HCV. This proposal will likely identify new therapeutic targets that can be manipulated in order to control HCV infection.
Interferon (IFN) based combination therapy remains as the mainstay platform for treatment of HCV wherein improving IFN response rates remains paramount to achieving global sustainable virological response. We are investigating the post-transcriptional regulation of interferon lambda genes which are critical to clearance of HCV infection. Outcomes from the study outlined in this proposal will likely provide new therapeutic targets that can be manipulated in order to control HCV infection.
|Savan, Ram (2014) Post-transcriptional regulation of interferons and their signaling pathways. J Interferon Cytokine Res 34:318-29|