Fat-loaded HepG2 spheroids exhibit enhanced protection from Pro-oxidant and cytokine induced damage
✍ Scribed by Leonard H. Damelin; Sam Coward; Michael Kirwan; Peter Collins; Clare Selden; Humphrey J. F. Hodgson
- Book ID
- 102300399
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 322 KB
- Volume
- 101
- Category
- Article
- ISSN
- 0730-2312
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✦ Synopsis
Abstract
The mechanisms by which steatosis renders hepatocytes susceptible to damage in non‐alcoholic steatohepatitis (NASH) are unclear although fat accumulation is believed to increase hepatocyte susceptibility to inflammatory cytokines and oxidative stress. We therefore investigated the susceptibility of steatotic, hepatocyte‐derived cells to TNFα and the pro‐oxidant, t‐butylhydroperoxide (TBH). HepG2 spheroids rendered steatotic by fat‐loading with 0.15 mM oleic or palmitic acid for 48 h and treated with TNFα or TBH for 18 h exhibited surprisingly lower levels of cytotoxicity, and increased anti‐oxidant activity (superoxide dismutase (SOD)) compared with non fat‐loaded controls. The protective effect of steatosis was significantly reversed by the inhibition of AMP‐activated kinase (AMPK) since spheroids transfected with a kinase‐dead AMPKα2 subunit, exhibited a significant increase in TBH‐induced cytotoxicity when fat‐loaded. In conclusion, our findings suggest that fat‐loaded hepatocyte‐derived cells are surprisingly less susceptible to cytokine and pro‐oxidant induced damage via an adaptive mechanism dependent, in part, on AMPK activity. J. Cell. Biochem. 101: 723–734, 2007. © 2007 Wiley‐Liss, Inc.