Interferon-alpha-induced mTOR activation is an anti-hepatitis C virus signal via the phosphatidylinositol 3-kinase-Akt-independent pathway

Autor: Hironori Yamasaki, Kazuhiko Nakao, Azusa Matsumoto, Eisuke Ozawa, Katsumi Eguchi, Satoshi Miuma, Shigeyuki Takeshita, Hisamitsu Miyaaki, Motohisa Akiyama, Kumi Hirano, Masanori Ikeda, Tatsuki Ichikawa, Hidetaka Shibata, Masumi Fujimito, Nobuyuki Kato
Rok vydání: 2008
Předmět:
Zdroj: Journal of gastroenterology. 44(8)
ISSN: 0944-1174
Popis: OBJECT: The interferon-induced Jak-STAT signal alone is not sufficient to explain all the biological effects of IFN. The PI3-K pathways have emerged as a critical additional component of IFN-induced signaling. This study attempted to clarify that relationship between IFN-induced PI3-K-Akt-mTOR activity and anti-viral action. RESULT: When the human normal hepatocyte derived cell line was treated with rapamycin (rapa) before accretion of IFN-alpha, tyrosine phosphorylation of STAT-1 was diminished. Pretreatment of rapa had an inhibitory effect on the IFN-alpha-induced expression of PKR and p48 in a dose dependent manner. Rapa inhibited the IFN-alpha inducible IFN-stimulated regulatory element luciferase activity in a dose-dependent manner. However, wortmannin, LY294002 and Akt inhibitor did not influence IFN-alpha inducible luciferase activity. To examine the effect of PI3-K-Akt-mTOR on the anti-HCV action of IFN-alpha, the full-length HCV replication system, OR6 cells were used. The pretreatment of rapa attenuated its anti-HCV replication effect in comparison to IFN-alpha alone, whereas the pretreatment with PI3-K inhibitors, wortmannin and LY294002 and Akt inhibitor did not influence IFN-induced anti-HCV replication. CONCLUSION: IFN-induced mTOR activity, independent of PI3K and Akt, is the critical factor for its anti-HCV activity. Jak independent mTOR activity involved STAT-1 phosphorylation and nuclear location, and then PKR is expressed in hepatocytes.
Journal of Gastroenterology, 44(8), pp.856-863; 2009
Databáze: OpenAIRE