HCV Activates Somatic L1 Retrotransposition-A Potential Hepatocarcinogenesis Pathway

Area of Science:

• Hepatology
• Molecular Biology
• Genetics

Background:

• Hepatocellular carcinoma (HCC) is frequently associated with Hepatitis C virus (HCV) infection.
• L1 retrotransposons are implicated in virus-associated HCC, but HCV's direct role is unclear.

Purpose of the Study:

• To investigate the direct influence of HCV on L1 retrotransposon activity.
• To determine if HCV-induced L1 retrotransposition contributes to genomic instability in HCC.

Main Methods:

• Analysis of L1 transcript expression in liver tissues from chronic HCV hepatitis (CHC) patients and healthy controls using RNA-seq.
• Immunohistochemical detection of L1orf1p protein in CHC liver samples.
• In vitro retrotransposition assays in Huh7 cells with and without an HCV replicon, including post-treatment with sofosbuvir.

Main Results:

• L1 transcript expression was significantly higher in CHC patients compared to controls.
• L1orf1p protein was detected in a majority of CHC liver samples.
• Replicating HCV RNA increased L1 retrotransposition rates, an effect that persisted after viral clearance.

Conclusions:

• HCV upregulates L1 retrotransposon expression and activity.
• HCV-induced retrotransposition may contribute to genomic instability and HCC development.
• This risk of transformation persists post-viral clearance, suggesting long-term molecular consequences of HCV infection.