Evaluation of deubiquiyinase USP15 expression during HCV replication

Abstract

Introduction and Objectives: This study aimed to evaluate the USP15 protein expression in HCV replication in vitro. Material and methods: Huh-7 cell line was transfected with pFKI plasmid that encodes for the non-structural HCV proteins; this expression is regulated by the T7 RNA polymerase promoter; therefore, prior to transfection, the cells were infected with Vaccinia Virus for T7 RNA polymerase expression. After 24 h of transfection, at 37°C and 5% CO2, total protein was extracted and quantified using the Bradford method. USP15 expression was evaluated by Western Blot assay using the antibodies for USP15, NS3-HCV and actin as a control. Results: The expression of NS3 was found in the transfected cells; in addition, a decrease in the expression of USP15 was observed compared to the control without viral proteins. Discussion: USP15 expression was shown to be downregulated in cells expressing HCV nonstructural proteins compared to control cells. A lower effect on USP15 expression was detected in the transfected cells compared to the HCV-replicon cells (positive control); this may be due to the low expression of NS3 in transfected cells. Therefore, we observed a decrease in USP15 expression dependent on NS3 expression. USP15 is known to regulate pathways including TLR signaling, RIG-I signaling, NF-kB, and IRF3/IRF7-dependent transcription to produce pro-inflammatory cytokines and type I interferons. Therefore it is important to elucidate the mechanisms involved in this regulation by HCV. Conclusion: USP15 expression is decreased in the presence of HCV nonstructural proteins. Funding: The resources used in this study were from the hospital without any additional financing Declaration of interest: The authors declare no potential conflicts of interest.