H4K20me3 and H3K79me3 epigenetic changes in Endometriosis and endometrial tissues (LB844)

The significance of epigenetic changes in the etiology and pathogenesis of endometriosis is being progressively recognized. However, the function of lysine‐histone epigenetic modifications and furthermore, their role in the pathology of this disease remains unclear. We lead a study aimed to identify specific epigenetic profiles and evaluate possible associations with gene expression to provide insights about the pathological processes occurring in endometriosis. Objective : Identify the methylation pattern of lysine‐histones H4K20me3 and H3K79me3 and chromatin modulation by gene activation in endometrial tissues. Methods: We used endometrial tissues from 9 women, with and without endometriosis. Macro‐dissection was achieved by following pathology protocols. Tissues were homogenized and disaggregated using a bullet blender. Total histone extraction was carried out using an Epiquick Kit (Epigentek) and then, western blots (WB) were performed. Both, the H4K20me3 and H3K79me3 were detected in all endometrial tissues by WB. Chromatin immuno‐precipitation (ChIP) assay was performed using an Epiquick Kit. The promoter gene region between ‐27024569‐ 27025759, 100027589 ‐ 100028694 and ‐41275101 ‐ 4127670 of the ARID1A (220 pb ), LOX‐4 (176 pb) and CTNNB1 (241 pb ) genes were amplified with the correspondent primers, designed using ENCODE at UCSC Genome Browser program. PCR products were electrophoresed, stained with SYBR ™ Green , and visualized. Results: There were higher levels of methylation of both 17kDa H4K20me3 and H3K79me3 in the endometrial tissue from women with endometriosis when compared to women without endometriosis (p < 0.05). ChIP assay demonstrated that ARID1A was expressed with H4K20me3, whereas with H3K79me3, it was silenced. However, Lox‐4 was silenced by both histones. Conclusion: Our results show that histone H4K20me3 and H3K79me3 modifications may be useful as a biomarker for detection and treatment of endometrial lesions. Grant Funding Source : NIH‐NICHD Grant # R01‐050559, NIGMS S06‐GM 08239 (IF) ARRA supplement to R01‐050559 (IF), RCMI G12‐MD007579, PRCTRC U54‐MD007587, NIH NIGMS R25GM096955 to UPR‐Ponce.