Fumonisin B1

Fumonisin B1 is a fungal metabolite produced by Fusarium moniliforme, that has been shown to inhibit protein serine/threonine phosphatases (PP1, PP2A, PP2B, PP2C, and PP5/T/K/H), and is most effective with PP5. It has been shown to stimulate the activation of mitogen-activated protein kinase. Fumonisin B1 has been observed to inhibit sphingolipid biosynthesis, preferentially inhibiting sphingomyelin biosynthesis versus glycosphingolipids in neuronal cells. In primary rat liver cells, fumonisin B1 blocked biosynthesis of de novo sphingolipids through LASS (ceramide synthase) inhibition. Caspase-3 activated or DNA fragmented apoptosis induced by fumonisin B1 binding to a TNF receptor has been documented in many human and rat cell lines. Fumonisin B1 has displayed immunotoxic effects by increasing expression of IL-1β, TNFα, IFN-γ; (interferon γ), IL-1α, IL-6, IL-10, IL-18 and IL-12 in varying mouse cells. Immunotoxicity of fumonisin B1 in human dendritic cells has been demonstrated through expression of chemokine CXCL9 and IFN-γ. Further, fumonisin B1 is an activator of Akt.