Knockdown of autophagy enhances the innate immune response in hepatitis C virus–infected hepatocytes

✍ Scribed by Shubham Shrivastava; Amit Raychoudhuri; Robert Steele; Ranjit Ray; Ratna B. Ray

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 323 KB
• Volume: 53
• Category: Article
• ISSN: 0270-9139
• DOI: 10.1002/hep.24073

✦ Synopsis

The role of autophagy in disease pathogenesis following viral infection is beginning to be elucidated. We have previously reported that hepatitis C virus (HCV) infection in hepatocytes induces autophagy. However, the biological significance of HCV-induced autophagy has not been clarified. Autophagy has recently been identified as a novel component of the innate immune system against viral infection. In this study, we found that knockdown of autophagy-related protein beclin 1 (BCN1) or autophagy-related protein 7 (ATG7) in immortalized human hepatocytes (IHHs) inhibited HCV growth. BCN1- or ATG7-knockdown IHHs, when they were infected with HCV, exhibited increased expression of interferon-β, 2',5'-oligoadenylate synthetase 1, interferon-α, and interferon-α-inducible protein 27 messenger RNAs of the interferon signaling pathways in comparison with infected control IHHs. A subsequent study demonstrated that HCV infection in autophagy-impaired IHHs displayed caspase activation, poly(adenosine diphosphate ribose) polymerase cleavage, and apoptotic cell death.

Conclusion:

The disruption of autophagy machinery in hcv-infected hepatocytes activates the interferon signaling pathway and induces apoptosis. together, these results suggest that hcv-induced autophagy impairs the innate immune response.