Publicação

Epigenetic changes in equine myometrium at different stages of endometrosis

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Resumo:	A reduction in the contractile activity of the myometrium can result in insufficient cleaning of the uterine lumen and the persistence of endometritis, leading to endometrosis. Studies in humans and other species point out to an important role for epigenetic mechanisms in gene expression regulation in the myometrium. However, in mares, there is a lack of information regarding the expression of enzymes responsible for DNA methylation (DNMTs) and demethylation (TETs) and the importance of these mechanisms. The main objective of this work was to determine the mRNA expression of these enzymes and explore the potential role of epigenetic mechanisms in the expression of genes encoding oxytocin (OXTR) and PGF2α (PTGFR) receptors in the myometrium of mares with endometrosis. Myometria were used in the midluteal (n=23) and follicular (n=20) phases of the estrous cycle. The material was grouped according to the corresponding endometrial classification (Kenney and Doig, 1986): category I (without pathological changes), IIA (mild endometrial fibrosis and/or inflammation), IIB (moderate endometrial fibrosis) and III (extensive endometrial fibrosis). Using qPCR method, the expression of DNMTs (DNMT1, DNMT3A, DNMT3B), TETs (TET1, TET2, TET3) and the expression levels of OXTR and PTGFR in the myometrium were determined. Using the bisulfite DNA pyrosequencing method, quantitative analysis (%) of DNA methylation was performed at specific sites (CpG islands) of two regions (exon 1 and 2) of OXTR gene. PTGFR did not have CpG islands and, thus, could not be analyzed. DNMT1 mRNA expression increased in myometrium in category IIA compared to category I in the follicular phase of the estrous cycle (P<0.05). The expression of TET2 mRNA was upregulated in the myometrium in categories I and IIB in the midluteal phase, compared to the follicular phase of the estrous cycle, also showing a positive regulation in category IIB compared to category I, in both phases (P <0.05). TET3 mRNA expression was increased in the myometrium in category IIA compared with category I in the follicular phase and was upregulated in category IIB in the follicular phase when compared with the midluteal phase of the estrous cycle (P<0.05). On the other hand, expression levels of OXTR and PTGFR and the global methylation (%) of OXTR in CpG islands did not show any significant differences between categories. However, an increase in DNA methylation was documented at position 6 of exon 2 of OXTR. The results suggest the potential regulatory role of epigenetic mechanisms in gene expression in the myometrium, related to changes in uterine contraction in mares with endometrosis
Autores principais:	Silva, Beatriz de Oliveira Celeiro e
Assunto:	Endometrosis Myometrium Epigenetics DNA Methylation Oxytocin Endometrose Miométrio Epigenética Metilação do DNA Oxitocina
Ano:	2024
País:	Portugal
Tipo de documento:	dissertação de mestrado
Tipo de acesso:	acesso aberto
Instituição associada:	Universidade de Lisboa
Idioma:	inglês
Origem:	Repositório da Universidade de Lisboa