Early Phosphoproteomic Changes in the Mouse Spleen During Deoxynivalenol-Induced Ribotoxic Stress

Abstract

The trichothecene mycotoxin deoxynivalenol (DON) targets the innate immune system and is of public health significance because of its frequent presence in human and animal food. DON-induced proinflammatory gene expression and apoptosis in the lymphoid tissue have been associated with a ribotoxic stress response (RSR) that involves rapid phosphorylation of mitogen-activated protein kinases (MAPKs). To better understand the relationship between protein phosphorylation and DON's immunotoxic effects, stable isotope dimethyl labeling-based proteomics in conjunction with titanium dioxide chromatography was employed to quantitatively profile the immediate (≤ 30min) phosphoproteome changes in the spleens of mice orally exposed to 5mg/kg body weight DON. A total of 90 phosphoproteins indicative of novel phosphorylation events were significantly modulated by DON. In addition to critical branches and scaffolds of MAPK signaling being affected, DON exposure also altered phosphorylation of proteins that mediate phosphatidylinositol 3-kinase/AKT pathways. Gene ontology analysis revealed that DON exposure affected biological processes such as cytoskeleton organization, regulation of apoptosis, and lymphocyte activation and development, which likely contribute to immune dysregulation associated with DON-induced RSR. Consistent with these findings, DON impacted phosphorylation of proteins within diverse immune cell populations, including monocytes, macrophages, T cells, B cells, dendritic cells, and mast cells. Fuzzy c-means clustering analysis further indicated that DON evoked several distinctive temporal profiles of regulated phosphopeptides. Overall, the findings from this investigation can serve as a template for future focused exploration and modeling of cellular responses associated with the immunotoxicity evoked by DON and other ribotoxins.

WITHDRAWN: Mitochondria: a critical target in the toxicity of trichothecenes and potential treatment strategies

“…Another report also showed that expression of modified tomato Rpl3 (double mutations in amino acid residues 258 and 259) in transgenic tobacco reduced the susceptibility to DON [14]. The binding of trichothecenes to the ribosomes could trigger a toxic response termed ribotoxic stress response (RSR), which was involved in rapid phosphorylation of mitogen-activated protein kinases (MAPKs, including ERK, JNK and p38) [15,16].…”

Early phosphoproteomic changes for adverse outcome pathway development in the fathead minnow (Pimephales promelas) brain

“…To our knowledge, this is one of few studies to examine rapid changes in phosphorylation after such a brief exposure in vivo other than the study by Pan et al . 31 and is certainly the first such study performed in fish. Further, no studies have probed the phosphoproteome as a target for environmental contaminants in ecotoxicological models using gel-free approaches as the only other phosphoproteomic analysis to our knowledge was performed in medaka fish ( Oryzias latipes ) exposed to mycrocystin-LR using 2D-gel electrophoresis coupled to LC-MS/MS 32 .…”

“…Limited studies have utilized LC-MS/MS based methods for the analysis of contaminant induced changes in phosphorylation in mammalian models and include an analysis of rat hepatoma cells exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin 12 , an analysis of oral administration of the environmental contaminant perfluorododecanoic acid in rat liver 13 , the effect of a mycotoxin on phosphorylation of proteins involved in innate immune responses in the mouse spleen 31 , and the modulation of arsenic toxicity to human kidney cells exposed to selenium 11 . To our knowledge, this is one of few studies to examine rapid changes in phosphorylation after such a brief exposure in vivo other than the study by Pan et al .…”

Protein phosphorylation profiling identifies potential mechanisms for direct immunotoxicity

“…Therefore, it would be interesting to use a more extended phosphoproteomics approach to screen a set of immunomodulating chemicals to get a more comprehensive overview of cell signaling pathways involved in chemical-induced immunotoxicity as well as to identify biomarkers of direct immunotoxicity at the phosphoproteome level. To date, phosphoproteomic-based approaches have led to an increased understanding of modes of action for a few immunotoxicants (Osman & van Loveren, 2012;Pan et al, 2013); however, a wide survey study is still lacking.…”