Investigating the antiviral role of cell death‐inducing DFF45‐like effector B in HCV replication

• Published in: The FEBS journal 2014-08, Vol.281 (16), p.3751-3765
• Main Authors: Singaravelu, Ragunath, Delcorde, Julie, Lyn, Rodney K., Steenbergen, Rineke H., Jones, Daniel M., Tyrrell, David Lorne, Russell, Rodney S., Pezacki, John P.
• Format: Article
• Language: English
• Subjects: Apoptosis; Apoptosis Regulatory Proteins - physiology; CARS microscopy; Caspase 3 - metabolism; Caspase 7 - metabolism; Caspases - metabolism; Cell Line, Tumor; cell‐inducing DFF45 like effector; Hepacivirus - physiology; Hepatitis; hepatitis C virus; Homeostasis; Host-Pathogen Interactions; Humans; lipid droplet; Lipid Metabolism; Lipids; Proteins; Triglycerides - metabolism; Virology; Virus Replication
• ISSN: 1742-464X; 1742-4658
• DOI: 10.1111/febs.12901

Cell‐death‐inducing DFF45‐like effector B (CIDEB) is an apoptotic host factor, which was recently found to also regulate hepatic lipid homeostasis. Herein we delineate the relevance of these dual roles of CIDEB in apoptosis and lipid metabolism in the context of hepatitis C virus (HCV) replication. We demonstrate that HCV upregulates CIDEB expression in human serum differentiated hepatoma cells. CIDEB overexpression inhibits HCV replication in HCV replicon expressing Huh7.5 cells, while small interfering RNA knockdown of CIDEB expression in human serum differentiated hepatoma cells promotes HCV replication and secretion of viral proteins. Furthermore, we characterize a CIDEB mutant, KRRA, which is deficient in lipid droplet clustering and fusion and demonstrate that CIDEB‐mediated inhibition of HCV is independent of the protein's lipid droplet fusogenic role. Our results suggest that higher levels of CIDEB expression, which favour an apoptotic role for the host factor, inhibit HCV. Collectively, our data demonstrate that CIDEB can act as an anti‐HCV host factor and contribute to altered triglyceride homeostasis. Here, we illustrate that hepatitis C virus (HCV) replication activates the expression of the liver abundant host factor CIDEB with known regulatory roles in hepatic lipid homeostasis and apoptosis. We demonstrate that siRNA mediated knockdown CIDEB overexpression increase HCV replication and CIDEB knockdown inhibits HCV replication and this inhibition is independent of CIDEB's role in lipid droplet clustering and fusion.