The Role of MicroRNA in Pathogenesis and as Markers of HCV Chronic Infection.

Hepatitis C virus (HCV) is a worldwide major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). Accumulating evidence indicates that a number of microRNAs (miRNAs), which are able to exert an effect on liver biology and pathology, can regulate or be regulated by HCV infection. Many studies demonstrate that HCV utilizes host miRNAs and modulates expression of miRNAs in infected hepatocytes for its infection and propagation. In turn, host miRNAs can directly regulate HCV replication through interaction with the HCV RNA genome or by indirectly controlling the host pathways associated with the virus replication, which eventually induce HCV-related liver diseases such as liver fibrosis, hepatic cirrhosis, or HCC. Recently, extracellular miRNAs (circulating miRNAs) detected in human serum and plasma are proposed as biomarker candidates for pathological conditions due to their remarkably stable nature and the non-invasiveness of their detection. Since these circulating miRNAs exhibit consistent levels between healthy individuals but significantly changed profiles in disease conditions, considerable effort has been employed to investigate the alteration in the circulating miRNA pattern that is related with HCV infection and associated liver diseases. In this review, we summarize the features of miRNAs critical for HCVassociated liver disease initiation and progress, and discuss growing evidence that distinctive circulating miRNA patterns are related with HCV infection and associated liver diseases. These will shed light on the development of miRNA-based therapeutic modalities and non-invasive biomarkers for the diagnosis and prognosis of HCV infection and associated diseases.