Characterization of Epigenetic and Molecular Factors in Endometrium of Females with Infertility

Abstract

Infertility is one of the most rapidly increasing global health concerns of the 21st century. Embryo quality and endometrial thickness and receptivity are the main factors for successful embryo implantation and pregnancy development. Nevertheless, until now, there has been a lack of understanding about the regulation of human endometrium function and its structure. This raises the demand for more research of the human endometrium in these fields. In our study, we analyzed the genetic and epigenetic changes of endometrial tissue's samples isolated from females admitted for treatment due to male infertility and females diagnosed with reproductive pathologies, who are preparing for assisted reproductive technologies procedures. Using real-time polymerase chain reaction method, we demonstrated that endometrium of females with reproductive pathology has significantly upregulated decidualization related genes HAND2, MUC1, CSF2, increased expression of angiogenesis related gene PDGFA, and increases of overall immune response and inflammation-related genes expression with significant changes of RELA and CXCL10 genes expression. Females with reproductive pathology have altered endometrium epigenetic regulation since expression of miRNAs-specifically, miRNA-34a, miRNA-223, and miRNA-125b-is lower in endometrium of females with reproductive pathology. Our findings suggest that the potential changes in genetic and epigenetic profile of endometrium from females with reproductive pathology could enrich the knowledge in the field of core biological knowledge and treatment of reproductive impairments.

Keywords: endometrial tissue; endometrium; infertility; reproduction; reproductive disorders; reproductive pathology.

Figure 1

Expression of decidualization and implantation related genes. Results are presented as mean ± standard deviation (red lines), triangle data points represent outliers based on ROUT (Q = 5%). In the control group, n = 11; in the pathology group, n = 14. * p ≤ 0.05; ** p ≤ 0.01; *** p ≤ 0.001; ns—not statistically significant, based on the Mann–Whitney U test.

Figure 2

Expression of angiogenesis-related genes. Results are presented as mean ± standard deviation (red lines); triangle data points represent outliers based on ROUT (Q = 5%). In the control group, n = 11; in the pathology group, n = 14. * p ≤ 0.05; ns—not statistically significant, based on the Mann–Whitney U test.

Figure 3

Expression of immune response and inflammation-related genes. Results are presented as mean ± standard deviation (red lines); triangle data points represent outliers based on ROUT (Q = 5%). In the control group, n = 11; in the pathology group, n = 14. * p ≤ 0.05; ns—not statistically significant, based on the Mann–Whitney U test.

Figure 4

Expression of miRNA related to regulation of genes of reproduction system cells. Results are presented as mean ± standard deviation (red lines); triangle data points represent outliers based on ROUT (Q = 5%). In the control group, n = 11; in the pathology group, n = 14. * p ≤ 0.05; *** p ≤ 0.001, based on the Mann–Whitney U test.

Figure 5

Evaluation of changes in protein levels in the control group and in the pathology group n = 4. (A) Proteins of decidualization pathways. (B) Histone modifications. Beta-Actin and histones H3 and H4 are control proteins. The intensity of the protein bands was estimated by the ImageJ program, and the levels of each protein were calculated according to the Beta-Actin, Akt, H3, and H4. Densitometric analysis graphs of relative band intensity of detected protein levels was measured using ImageJ software and normalized to the loading control. Results are presented as mean ± standard deviation; triangle data points represent outliers based on ROUT (Q = 5%); ns—not statistically significant, based on the Mann–Whitney U test.