Morphological changes in intracellular lipid droplets induced by different hepatitis C virus genotype core sequences and relationship with steatosis

Hepatocellular steatosis is common in patients with chronic hepatitis C. Steatosis can be considered as a true cytopathic lesion induced by hepatitis C virus (HCV) genotype 3, suggesting that one or more viral proteins produced during genotype 3 infection are involved in the steatogenic process, while the same proteins produced during infection by other genotypes are not. We examined in vitro interactions between lipid droplets and full-length core protein isolated from patients with HCV genotype 3a infection, with and without steatosis, and from steatosis-free patients infected by HCV genotype 1b. We also examined morphological changes in the lipid droplets according to the HCV genotype and the presence of steatosis in vivo. Core protein processing by signal peptide peptidase was not affected by sequence differences between the variants. We showed that the core protein of both HCV genotypes 1b and 3a binds tightly to the surface of intracellular lipid droplets. However, cells transfected with genotype 3a contain more neutral lipids in lipid droplets, and more large lipid droplets, than cells transfected with genotype 1b sequences. This suggests that HCV core protein-lipid droplet interaction could play a role in virus-induced steatosis. Importantly, we found no genetic or functional differences between genotype 3a core proteins from patients with and without HCV-induced steatosis. Conclusion: This suggests that other viral proteins and/or host factors are involved in the development of hepatocellular steatosis in patients infected by HCV genotype 3a.