Investigation Of Differentially Expressed Methylated Genes And Regulatory Effect Of TET2 In Psoriasis

Objective: Psoriasis is a systemic,chronic and hereditary skin disease,with an elusive pathogenesis.Although the biologics could alleviate the condition of some patients,but the dilemma of recurrence of this disease has not changed,and seriously affects the quality of life.Studies have shown that epigenetics also plays an important role in the pathogenesis of psoriasis expect for genetic factors.This study aimed to investigate the differentially expressed methylated genes and the regulatory effect of ten-eleven translocation(TET)2 on these genes in psoriasis through integrated bioinformatics and basic biological experiment.Methods: 1.Gene expression profiles GSE13355,GSE14905 and GSE78097 as well as DNA methylation profile GSE31835 were downloaded from GEO database.Differentially expressed genes(DEGs)were identified.Three lists of DEGs were integrated to obtain common DEGs and the biological functions were explored.The protein-protein interaction(PPI)network was constructed for functional enrichment analysis and hub genes screening.2.The GEO2 R online tool was used to identify genes and its differences in methylation.After intersecting with the DEGs list,the differentially methylated genes(DMGs)were obtained.The PPI network was constructed for functional enrichment analysis and hub genes screening.3.The mice were randomly divided into three groups,(1)control group: Vaseline+negative control virus;(2)imiquimod(IMQ)model group: IMQ+negative control virus;(3)TET2 interference group: IMQ+TET2 silenced lentivirus.The skin tissues of mice were obtained for hematoxylin-eosin(HE)staining,Western blot,and real-time quantitative polymerase chain reaction(q RT-PCR).4.Specific si RNA and overexpressed plasmid of TET2 were constructed for Western blot,q RT-PCR and dot blot.Results: 1.951,1530 and 2836 DEGs were obtained from GSE13355,GSE14905 and GSE78097,respectively.498 common DEGs included 352 up-regulated,137 down-regulated and 9 non-specific genes.Gene Ontology(GO)analysis suggested that up-regulated genes were mainly involved in type I interferons(IFNs)signaling pathway,while down-regulated genes were mainly involved in cell adhesion.Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis showed that up-regulated genes were mainly involved in the influenza A signaling pathway,while downregulated genes were mainly involved in the tight junction.12 hub genes were screened out using Cyto Hubba.Clue GO analysis showed key gene modules were mainly involved in cell cycle.2.A total of 2730 genes with difference in methylation were identified and 95 DMGs were obtained after integrating DEGs list.11 hub genes were screened out using Cyto Hubba.Clue GO analysis showed that the genes in PPI network were mainly involved in interleukin(IL)-17 signaling pathway.3.In vivo experiment,HE staining results showed that skin lesions of the mice in the TET2 interference group were less than IMQ model group,whereas no obvious abnormalities were found in control group.Western blot and q RT-PCR showed that the expression of TET2 and six hub genes in the TET2 interference group was significantly lower than IMQ model group.4.In vitro experiment,TET2 si RNA and overexpressed plasmid were successfully constructed.The levels of 5-hydroxymethylcytosine(5hm C)and six hub genes were markedly down-regulated in the si RNA group compared to control group.However,the levels were markedly up-regulated in the plasmid group compared to control group.Conclusion: We identified a series of DMGs in psoriasis through integrated bioinformatics analysis,and these DMGs may be potential biomarkers for diagnosis and treatment of psoriasis.Although the expression of some DMGs was verified by in vivo and in vitro experiment,further experiments are needed to explore the important role of DMGs screened in this study in the pathogenesis of psoriasis.