Fumonisin B 1-induced alterations in cytokine expression and apoptosis signaling genes in mouse liver and kidney after an acute exposure

Abstract

Fumonisin B 1 (FB 1), a carcinogenic mycotoxin produced primarily by fungus Fusarium verticillioides in corn, causes several fatal animal diseases. In mice, liver is the primary site of its toxicity. Our previous study showed that maximum induction of interferon γ (IFNγ) and tumor necrosis factor α (TNFα) was observed at 4 and 8 h, respectively, after an acute po FB 1 treatment. To further investigate the time-related induction of other cytokines and genes involved in apoptosis signaling, male BALB/c mice were administered orally with either saline or 25 mg/kg of FB 1 and sampled 4 or 8 h after treatment. Expression of various genes was analyzed by ribonuclease protection assay. FB 1 treatment caused increased expression of TNFα and interleukin (IL)-1β in both liver and kidney, whereas IL-1α and IL-1 receptor antagonist (IL-1Ra) expression was induced only in the liver. Expression of TNFα signaling molecules, TNF receptor 55 and receptor interacting protein, was increased in liver and kidney after FB 1 treatment. Caspase 8 expression was increased only in liver with no changes in kidney with FB 1. FB 1 treatment induced expression of Fas in liver and kidney with no alterations in Fas signaling molecules, Fas ligand, Fas-associated death domain and Fas-associated protein factor. Treatment of mice with FB 1 increased the expression of B-Myc, c-Myc and Max, oncogenic transcription factors in the kidney. FB 1 toxicity caused induction of cytokine network in liver with involvement of TNFα signaling pathway. Increased expression of caspase 8 involved in the TNFα signaling pathway may contribute to the apoptosis, whereas IL-1Ra induction could contribute to the proliferating effects observed in FB 1 toxicity.