Fusarial toxin-induced toxicity in cultured cells and in isolated mitochondria involves PTPC-dependent activation of the mitochondrial pathway of apoptosis.
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(2)(.-) 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-alpha 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-x(L) 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.
Bouaziz
Chayma
C
Laboratory of Research on Biologically Compatible Compounds, Faculty of Dentistry, Monastir 5000, Tunisia.
Martel
Cécile
C
Sharaf el dein
Ossama
O
Abid-Essefi
Salwa
S
Brenner
Catherine
C
Lemaire
Christophe
C
Bacha
Hassen
H
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D052160:Benzothiazoles / Q000494:pharmacology; D053148:Caspase 3 / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D045304:Cytochromes c / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D005670:Fusarium / Q000737:chemistry*; D045325:HCT116 Cells; D006367:HeLa Cells; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008930:Mitochondria, Liver / Q000187:drug effects / Q000473:pathology; D033681:Mitochondrial Membrane Transport Proteins / Q000819:agonists* / Q000378:metabolism; D000083162:Mitochondrial Permeability Transition Pore; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013481:Superoxides / Q000378:metabolism; D013605:T-2 Toxin / Q000302:isolation & purification / Q000633:toxicity*; D013997:Time Factors; D014050:Toluene / Q000031:analogs & derivatives / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000378:metabolism; D015025:Zearalenone / Q000302:isolation & purification / Q000633:toxicity*; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D051020:bcl-X Protein / Q000378:metabolism
C494826:BAX protein, human; D052160:Benzothiazoles; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D019253:Proto-Oncogene Proteins c-bcl-2; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D013481:Superoxides; D014050:Toluene; D015025:Zearalenone; D045304:Cytochromes c; C121565:pifithrin; C505407:CASP3 protein, human; D053148:Caspase 3; D013605:T-2 Toxin