Truncated deoxynivalenol-induced splenic immediate early gene response in mice consuming (n-3) polyunsaturated fatty acids.

Expression profiling has previously revealed that acute exposure to the common foodborne mycotoxin deoxynivalenol (DON) induces a large number of immediate early genes in murine lymphoid tissues that potentially affect immune function. The purpose of this study was to test the hypothesis that consumption of (n-3) polyunsaturated fatty acids (PUFAs) found in fish oil interferes with DON-induced immediate early gene expression. Mice were fed AIN-93G diet containing 1% corn oil (CO) plus 6% oleic acid (control) or a diet containing 1% CO, 2% fish oil enriched in the (n-3)-PUFAs docosahexaenoic and eicosapentaenoic acid and 4% oleic acid. After 12 weeks, the mice were gavaged orally with 25 mg/kg DON and the kinetics of immediate early gene expression in spleen monitored over 8 h by real-time polymerase chain reaction (PCR). Deoxynivalenol was found to readily induce expression of cytokines (IL-1alpha, IL-1beta, and IL-6 and IL-11), chemokines (MCP-1, MCP-3, CINC-1 and MIP-2), components of the activator protein-1 (AP-1) transcription factor complex (c-Fos, Fra-2, c-Jun and JunB), as well as two hydrolases (MKP1, CnAbeta). Expression of these genes was transient, peaking within 2-4 h and declining thereafter, with the single exception being IL-11 that was elevated at 8 h. (n-3)-PUFA consumption significantly suppressed DON-induced expression of IL-1alpha, IL-6, IL-11, MCP-1, MCP-3, MIP-2 and Fra-2 at 8 h. In contrast, mice fed (n-3)-PUFA exhibited significant increases in MKP1 and CnAbeta expression. Taken together, these data suggest that dietary supplementation with (n-3)-PUFAs prematurely truncated cytokine, chemokine and transcription factor expression responses to DON that may impact its previously described capacity to disrupt immune function including immunoglobulin A (IgA) production. Since expression of many of these genes has been linked to mitogen-activated protein kinase (MAPK) activation, enhanced expression of MKP1, a negative MAPK regulator in (n-3)-PUFA-fed mice might contribute to this suppression.

Gene expression profiling in spleens of deoxynivalenol-exposed mice: immediate early genes as primary targets.

Exposure to the trichothecene mycotoxin deoxynivalenol (DON) alters immune functions in vitro and in vivo. To gain further insight into DON's immunotoxic effects, microarrays were used to determine how acute exposure to this mycotoxin modulates gene expression profiles in murine spleen. B6C3F1 mice were treated orally with 25mg/kg body weight DON, and 2h later spleens were collected for macroarray analysis. Following normalization using a local linear regression model, expression of 116 out of 1176 genes was significantly altered compared to average expression levels in all treatment groups. When genes were arranged into an ontology tree to facilitate comparison of expression profiles between treatment groups, DON was found primarily to modulate genes associated with immunity, inflammation, and chemotaxis. Real-time polymerase chain reaction was used to confirm modulation for selected genes. DON was found to induce the cytokines interleukin (IL)-1alpha, IL-1beta, IL-6 and IL-11. In analogous fashion, DON upregulated expression of the chemokines macrophage inhibitory protein-2 (MIP-2), cytokine-induced chemoattractant protein-1 (CINC-1), monocyte chemoattractant protein (MCP)-1, MCP-3, and cytokine-responsive gene-2 (CRG-2). c-Fos, Fra-, c-Jun, and JunB, components of the activator protein-1 (AP-1) transcription factor complex, were induced by DON as well as another transcription factor, NR4A1. Four hydrolases were found to be upregulated by DON, including mitogen-activated protein kinase phosphatase 1 (MKP1), catalytic subunit beta isoform (CnAbeta), protein tyrosine phosphatase receptor type J (Ptprj), and protein tyrosine phosphatase nonreceptor type 8 (Ptpn8), whereas three other hydrolases, microsomal epoxide hydrolase (Eph) 1, histidine triad nucleotide binding protein (Hint), and proteosome subunit beta type 8 (Psmb8) were significantly decreased by the toxin. Finally, cysteine-rich protein 61 (CRP61) and heat-shock protein 40 (Hsp40), genes associated with signaling, were increased, while Jun kinase 2 (JNK2) was decreased. Taken together, data suggest that DON upregulated the expression of multiple immediate early genes, many of which are likely to contribute to the complex immunological effects reported for this and other trichothecenes.