Knock down of gamma-glutamylcysteine synthetase in rat causes acetaminophen-induced hepatotoxicity.

Abstract

Drug-induced hepatotoxicity is mainly caused by hepatic glutathione (GSH) depletion. In general, the activity of rodent glutathione S-transferase is 10 to 20 times higher than that of humans, which could make the prediction of drug-induced hepatotoxicity in human more difficult. Gamma-glutamylcysteine synthetase (gamma-GCS) mainly regulates de novo synthesis of GSH in mammalian cells and plays a central role in the antioxidant capacity of cells. In this study, we constructed a GSH-depletion experimental rat model for the prediction of human hepatotoxicity. An adenovirus vector with short hairpin RNA against rat gamma-GCS heavy chain subunit (GCSh) (AdGCSh-shRNA) was constructed and used to knock down the GCSh. In in vitro study in H4IIE cells, a rat hepatoma cell line, GCSh mRNA and protein were significantly decreased by 80% and GSH was significantly decreased by 50% 3 days after AdGCSh-shRNA infection. In the in vivo study in rat, the hepatic GSH level was decreased by 80% 14 days after a single dose of AdGCSh-shRNA (2 x 10(11) pfu/ml/body), and this depletion continued for at least 2 weeks. Using this GSH knockdown rat model, acetaminophen-induced hepatotoxicity was shown to be significantly potentiated compared with normal rats. This is the first report of a GSH knockdown rat model, which could be useful for highly sensitive tests of acute and subacute toxicity for drug candidates in preclinical drug development.

• Authors: Sho Akai, Hiroko Hosomi, Keiichi Minami, Koichi Tsuneyama, Miki Katoh, Miki Nakajima, Tsuyoshi Yokoi
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 282 Issue 33 Pg. 23996-4003 (Aug 17 2007) ISSN: 0021-9258 [Print] United States
• PMID: 17573345 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• RNA, Small Interfering
• Acetaminophen
• Glutamate-Cysteine Ligase
• Glutathione

Topics

• Acetaminophen (pharmacology)
• Animals
• Cell Line
• Chemical and Drug Induced Liver Injury (diagnosis, etiology)
• Disease Models, Animal
• Drug Synergism
• Gene Silencing
• Glutamate-Cysteine Ligase (deficiency, genetics)
• Glutathione (analysis, drug effects)
• RNA, Small Interfering (pharmacology)
• Rats