Disturbance In Transcriptome Profiling And DNA Methylome By Neonicotinoids In Human Mesenchymal Stem Cells

Neonicotinoids exhibit high selectivity to nicotinic acetylcholine receptor(nAChR)of insects,with relatively low toxicity to mammals.However,increasing researches have found that neonicotinoids not only act on the non-target bees,but also pose harmful effects on mammals.Neonicotinoids increased the risks of tumorigenesis in mice and rats,but the mechanism is still unclear.In the present study,due to the crucial early regulating of epigenetics in health hazards caused by environmental pollutants,the effects of neonicotinoids on DNA methylation in human bone marrow mesenchymal stem cells(hBMSCs)were studied.Moreover,integrative analysis was used to elucidate the role of disturbed DNA modification in the abnormal gene expression of.Furthermore,the gene profile in hBMSCs was compared to that of the rat to identify the crossing-species molecular targets and to illustrate the the species difference of toxicity of neonicotinoids.The results show that:(1)ACE,NIT and CYC inhibited the genome methylation of hBMSCs,which may be caused by the demethylation process mediated by TET.TMX increased the methylation level of hBMSCs genome.The effect of DIN on the genome methylation is not clear.(2)ACE exposure changed the methylation level of 87 loci and 21 regions in hBMSCs genome.16 pathways were enriched by differentially methylated genes(DMGs),among which Alzheimer's disease,dopaminergic synapse,apoptosis and hepatitis C are central nodes in the network.GSK3 B,ITPR2,EIF2AK3 and 1EIF2S1 were enriched in multiple pathways,which seemed to be sensitive to ACE exposure.(3)A total of 501 differentially expressed genes(DEGs)and 34 pathways were enriched after exposure to ACE.CXCL8,THBS1,CCND2,MDM2,EGF and WISP1,were identified as the hub genes by DEGs network analysis.The intersection analysis of DEGs and DMGs showed that ABI3 BP and CCL26 genes were simultaneously differentially expressed and methylated.Integrative network analysis of DEGs and DMGs showed 20 hub genes were identified,among which RELN,NOS1 and SMAD2 were differentially methylated.(4)Cross-species analysis of the expression profile showed that after exposure to tested neonicotinoids,FMO3,EGR3,MYCT1 and HMGA2,were commonly affected in both hBMSCs and rat neurons.Pathways analysis showed JAK-STAT pathway and PPAR pathway were affected in both hBMSCs and rat cerebellar neurons.A number of pathways related to cell cycle regulation and cancer were exclusively affected in hBMSCs.WGCNA analysis showed that the gene clusters with different co-expression patterns were species specific.The present study showed that after exposure to neonicotinoids,global DNA methylation,DNA methylome and gene expression profile homeostasis of hBMSCs were interfered.The affected target genes and biological pathways were mainly related to nervous system and cancer,suggesting further study for the adverse heath effects.The results provided scientific evidence for the toxicological research and health risk assessment for neonicotinoids.