Zhongtian Qi
Second Military Medical University, China
Title: Exosomal miRNAs derived from umbilical mesenchymal stem cells inhibit hepatitis C virus infection
Biography
Biography: Zhongtian Qi
Abstract
Background & Aim: Hepatitis C virus (HCV) infects approximately 3% of the world population. Though the development of direct acting antivirals (DAAs) have improved the sustainable virological response (SVR) rate in HCV patients, novel anti-HCV agents with higher efficacy and better tolerance are still urgently needed. Cell-based therapy, like exosomes, has become one of the most popular therapeutic methods in recent years.
Methods: Conditioned medium from umbilical mesenchymal stem cells (uMSC) is used to test its effect on HCV infection. Exosomes are further extracted and purified from the supernatants of uMSC (uMSC-Exo), and its anti-HCV activity is evaluated. Single cycle HCV pseudoparticles are applied to determine the effect of uMSC-Exo on HCV entry. Host cells are transfected with viral RNA or HCV replicon cells are utilized to detect the effect of uMSC-Exo on viral replication. The intracellular and extracellular infectivity are also evaluated to test the effect of uMSC-Exo on viral assembly and release. Proteinase K treatment assay is used to determine which components in uMSC-Exo are the functional substances. Small RNA sequencing is made with uMSC-Exo, and miRNAs with antiviral potency are identified. Function analysis is carried out by overexpression or knock down of relevant miRNAs, and their roles in inhibiting HCV infection are evaluated.
Results: uMSC inhibit HCV infection by paracrine, and uMSC-Exo are the main active constituents in this process. uMSC-Exo can enter Huh7 cells and reduce intracellular HCV RNA level as well as viral protein expression in infected cells. uMSC-Exo have no effect on viral entry, but suppress viral replication. Proteinase K treatment assay confirms that the RNA components are the active anti-HCV constituents in uMSC-Exo. Small RNA sequencing of uMSC-Exo indicates their miRNA expression profile. Among them, nine miRNAs are upregulated in the host cells after uMSC-Exo treatment. The functional analysis suggests four miRNAs (let-7f, miR-145, miR-199a and miR-221) play important roles in HCV infection. The inhibitory effect of uMSC-Exo is lost when the uMSC are transfected with the inhibitors of the four miRNAs.uMSC-Exo exhibit synergistic effect when combined with IFN or VX-950.
Conclusion: uMSC-Exo inhibits HCV infection by exosomal miRNAs (let-7f, miR-145, miR-199a and miR-221) with antiviral activity on viral replication. This work provides novel insights and possibility for developing anti-HCV therapy.