Topological and evolutional relationships between HCV core protein and hepatic lipid vesicles: studies in vitro and in conditionally transgenic mice.
OBJECTIVE
To investigate a specific association between hepatic steatosis and hepatitis C virus (HCV) core.


METHODS
HeLa cells and primary mouse hepatocytes were transfected with HCV core plasmid, and conditional transgenics in which hepatic over-expression of HCV core is regulated by the tetracycline-off system, were developed. The expression of the HCV core was assessed over one to six months after withdrawal of doxycycline (dox) by immunohistochemistry (IHC) and Western blotting and by sequential liver biopsy. Hepatic steatosis was evaluated using oil red stain. 8-hydroxydeoxyguanosine (8-OHdG) stains and caspase levels were conducted to clarify hepatic oxidative stress and apoptosis rate. Serum aminotransferase was checked.


RESULTS
The transfected hepatocytes had globular cores under the lipid vesicles. In transgenic mice on control diet, core expression was robust, localized to the cytoplasmic vesicle membrane and strongly associated with microvesicular steatosis, which was gradually replaced by macrovesicular steatosis. However, both steatosis and core positive hepatocytes diminished with time. Increases in aminotransferase, caspase and 8-OHdG were associated with peak core expression.


CONCLUSIONS
The core protein was readily detected and morphologically associated with steatosis in individual hepatocytes both in vitro and in vivo. In vivo, oxidative stress caused by the core potentially reduced the number of core positive hepatocytes and in parallel the level of steatosis. To our knowledge, this is the first animal model that directly shows topological relationship between HCV core and hepatic lipid vesicles.
Liver Research Unit, Department of Hepatogastroenterology, Chang Gung Memorial Hospital, No. 5 Fu Hsing Street, Kuei Shan, Taoyuan, Taiwan, China. kitty8210@yahoo.com
Ming-Ling
ML
Chang
Jeng-Chang
JC
Chen
Chau-Ting
CT
Yeh
I-Shyan
IS
Sheen
Dar-In
DI
Tai
Ming-Yu
MY
Chang
Cheng-Tang
CT
Chiu
Deng-Yn
DY
Lin
D Montgomery
DM
Bissell
D000818:Animals; D017209:Apoptosis; D005234:Fatty Liver / Q000209:etiology*; D005260:Female; D006367:HeLa Cells; D006526:Hepatitis C / Q000150:complications*; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D018384:Oxidative Stress; D014758:Viral Core Proteins / Q000502:physiology*
D014758:Viral Core Proteins