ToxSci Advance Access originally published online on June 18, 2009
Toxicological Sciences 2009 110(2):363-375; doi:10.1093/toxsci/kfp117
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Fusarial Toxin–Induced Toxicity in Cultured Cells and in Isolated Mitochondria Involves PTPC-Dependent Activation of the Mitochondrial Pathway of Apoptosis
* Laboratory of Research on Biologically Compatible Compounds, Faculty of Dentistry, Monastir 5000, Tunisia
Laboratoire de Génétique et Biologie Cellulaire, CNRS-UMR 8159, Université de Versailles/SQY, Versailles 78035, France
1 To whom correspondence should be addressed at Laboratory of Research on Biologically Compatible Compounds, Faculty of Dentistry, Rue Avicenne, Monastir 5000, Tunisia. Fax: +216-73461150. E-mail: hassen.bacha{at}fmdm.rnu.tn.
Received December 11, 2008; accepted May 1, 2009
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Abstract |
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Mycotoxins produced by the Fusarium molds can cause a variety of human diseases and economic losses in livestock. Fusaria produce predominantly two types of mycotoxins: the nonestrogenic trichothecenes including T-2 toxin and the mycoestrogens such as zearalenone (ZEN). In a previous report, we demonstrated that the hepatotoxicity of these mycotoxins involves the mitochondrial pathway of apoptosis. Here, we observed that both fusarotoxins induced cell death by a mitochondria-dependent apoptotic process which includes opening of the mitochondrial permeability transition pore complex (PTPC), loss of mitochondrial transmembrane potential, increase in O
production, mitochondrial relocalization of Bax, cytochrome c release, and caspase activation. Studies performed on isolated mouse liver mitochondria showed that both ZEN and T-2 toxin might act directly on mitochondria to induce a PTPC-dependent permeabilization of mitochondrial membranes. Moreover, they may target different members of PTPC. Indeed, although the inner membrane protein adenine nucleotide translocase could be the target of T-2 toxin, ZEN seems to target the outer membrane protein voltage-dependent anion channel. Cells pretreatment with the p53 inhibitor pifithrin-
suggested that ZEN but not T-2 toxin triggered a p53-dependent mitochondrial apoptotic pathway. Finally, mitochondrial alterations induced by ZEN and T-2 toxin are mediated by Bcl-2 family proteins, such as Bax, and prevented by Bcl-xL and to a lesser extent by Bcl-2. Taken together, these data indicate that mitochondria play a pivotal role in both ZEN- and T-2 toxin–induced apoptosis and that PTPC members and proteins of Bcl-2 family should be interesting targets to overcome fusarotoxin toxicity.
Key Words: Zearalenone; T-2 toxin; apoptosis; mitochondria; PTPC; Bcl-2.