Proteomic Analysis Of The Toxic Effect Of Zearalenone On Mouse Thymic Epithelial Cells

Mycotoxins,the toxic metabolites of various common fungi in feeds and foods,are one of the most common pollutants in cereal crops worldwide.Zearalenone(ZEA)is a kind of lactone compounds with similar structure and estrogenic activity,which is susceptible to disease in humans.Thymic epithelial cells(TECs)constitute a unique thymic microenvironment which is necessary for thymocyte proliferation,differentiation,and selection.Changes in thymic epithelial cells directly affect the differentiation,development,and maturation of thymic T lymphocytes.In this study,mouse thymic epithelial cell line 1(MTEC1)were selected as the research object to investigate the toxic effects of ZEA on MTEC1 cells and its possible molecular mechanisms.The effects of ZEA on MTEC1 cell viability,mtDNA,reactive oxygen species,mitochondrial membrane potential,cell cycle,cell necrosis,ATP,changes in the expression of proliferation-related proteins were detected by using the methods of CCK-8 method,proteomics,qRT-PCR,immunofluorescence staining,flow cytometry,luciferase detection and Western blot,the results were as follows:(1)ZEA can significantly inhibit the proliferation of MTEC1 cells and decrease cell viability.(2)ZEA can cause changes in the protein expression profile of MTEC1 cells.The results showed that the ZEA-treated group detected a total of 596 differentially significant proteins,245 proteins up-regulations,and 351 proteins down-regulations,in particular significant changes in metabolic-related proteins.The analysis of Gene Ontology(GO)showed that after ZEA treatment of MTEC1 cells,the differentially expressed proteins were mainly involved in GO term,such as protein synthesis,oxidative phosphorylation and mitochondrial metabolism.(3)ZEA can cause mitochondrial dysfunction in MTEC1 cells by increasing reactive oxygen species(ROS)levels,reducing mtDNA copy number,decreasing mitochondrial membrane potential(??m),and ATP depletion.(4)ZEA can cause necrosis of MTEC1 cells through mitochondrial metabolic disorders.(5)ZEA blocked MTEC1 cell proliferation in the G2/M phase and was significantly down-regulated with protein levels of cell proliferation-associated proteins including ERK,p-ERK,CDK1 and p-CHK1.Conclusions: Mitochondrial dysfunction is an early event of ZEA-induced MTEC1 cell injury.ZEA can induce cell necrosis by causing mitochondrial dysfunction,while blocking cell cycle in G2/M phase and inhibiting cell proliferation by down-regulating some cell proliferation-related proteins.