Integrative Analysis Of DNA Methylome And Transcriptome Of The Eutopic Endometrium Of Adenomyosis By Whole-genome Bisulfite Sequencing And RNA Sequencing

Objective:Adenomyosis is a common gynecological disease.However,the pathogenesis is still unknown.The most accepted theory is that the endometrium from uterine cavity invaginates into the myometrium.Previous studies have found a variety of alterations in the eutopic endometrium of adenomyosis at the molecular level.Some reaserchers have found that epigenetics is involved in the pathogenesis of adenomyosis.However,there is still little research on the epigenetic alteration in the eutopic endometrium of adenomyosis.DNA methylation is one of the important parts of epigenetics.Previous studies have found abnormal expression of DNA methyltransferases in the eutopic endometrium of adenomyosis,but have not fully descibed the DNA methylation landscape.Therefore,we conducted this study to explore the precise DNA methylation changes and their contribution to altered transcriptional patterns in the eutopic endometrium of adenomyosis,and provide candidate genes for further mechanistic studies.Methods:6 eutopic endometrium samples of adenomyosis and 3 normal endometrium samples were collected after hysterectomy at Peking Union Medical College Hospital.Then,we conducted whole-genome bisulfite sequencing and RNA sequencing.The differentially methylated regions(DMRs)and differentially expressed genes between the two groups were analyzed through bioinformatics analysis.Integrative analysis was later conducted to determine whether the associated genes to each DMR was differentially expressed and candidate genes were screened.Results:1443 differentially methylated regions were found in the eutopic endometrium of adenomyosis compared with the normal control endometrium,of which 230 differentially methylated regions were predicted to be gene regulatory regions,including 127 hypermethylated regions with 182 associated genes,and 103 hypomethylated regions with 146 associated genes.RNA sequencing detected 1217 differentially expressed genes between the two groups.In the eutopic endometrium of adenomyosis,there were 926 genes with increased expression and 291 genes with decreased expression.Integrative analysis showed that 11 protein-coding genes had changes in both methylation in the regulatory region and expression.In the GO analysis,these genes were enriched in regulation of mesoderm development,cell-cell junction,Wnt protein binding,etc.The signaling pathway analysis indicated enrichment in Wnt signaling pathway and Hippo signaling pathway,etc.Among these,there were negative correlation between methylation and expression for FM02,TP63,CADM2,DLG2 and CCDC178.In the adenomyosis group,TP63,DLG2 and CCDC178 were hypomethylated in the gene regulatory region and highly expressed.In previous researches,these three genes were reported to be involved in cell proliferation,apoptosis,differentiation,migration,inflammation and fibrosis.Conclusion:In this study,we conducted whole-genome bisulfite sequencing and RNA sequencing for the eutopic endometrium of adenomyosis.As far as we know,the DNA differential methylation landscape of the eutopic endometrium of adenomyosis was drawn for the first time.We propose that TP63,DLG2,CCDC178 with altered methylation and expression may be promising candidate genes for further studies of the epigenetic pathogenesis of adenomyosis.