Urokinase-Type Plasminogen Activator and Insulin-Like Growth Factor-Binding Protein 3 mRNA Expression in Endometriotic Lesions and Eutopic Endometrium

MicroRNA-210-3p Regulates Endometriotic Lesion Development by Targeting IGFBP3 in Baboons and Women with Endometriosis

MicroRNAs (miRs) play an important role in the pathophysiology of endometriosis; however, the role of miR-210 in endometriosis remains unclear. This study explores the role of miR-210 and its targets, IGFBP3 and COL8A1, in ectopic lesion growth and development. Matched eutopic (EuE) and ectopic (EcE) endometrial samples were obtained for analysis from baboons and women with endometriosis. Immortalized human ectopic endometriotic epithelial cells (12Z cells) were utilized for functional assays. Endometriosis was experimentally induced in female baboons (n = 5). Human matched endometrial and endometriotic tissues were obtained from women (n = 9, 18-45 years old) with regular menstrual cycles. Quantitative reverse transcript polymerase chain reaction (RT-qPCR) analysis was performed for in vivo characterization of miR-210, IGFBP3, and COL8A1. In situ hybridization and immunohistochemical analysis were performed for cell-specific localization. Immortalized endometriotic epithelial cell lines (12Z) were utilized for in vitro functional assays. MiR-210 expression was decreased in EcE, while IGFBP3 and COL8A1 expression was increased in EcE. MiR-210 was expressed in the glandular epithelium of EuE but attenuated in those of EcE. IGFBP3 and COL8A1 were expressed in the glandular epithelium of EuE and were increased compared to EcE. MiR-210 overexpression in 12Z cells suppressed IGFBP3 expression and attenuated cell proliferation and migration. MiR-210 repression and subsequent unopposed IGFBP3 expression may contribute to endometriotic lesion development by increasing cell proliferation and migration.

Expression and Role of Peptides, Proteins and Growth Factors in the Pathogenesis of Endometriosis

Growing evidence is demonstrating that several peptides (corticotrophin-releasing factor, urocortins, ghrelin), proteins (leptin, adiponectin) and growth factors (vascular endothelial growth factor; epidermal growth factor family of growth factors and receptors, fibroblast growth factor, insulin like growth factor and insulin like growth factor-binding proteins, transforming growth factor-β and, activin A and related proteins) are expressed in endometriotic implants, and locally play a relevant role in affecting the biological mechanisms leading to endometriosis. They establish a complex network of interactions by which they are therefore able to stimulate angiogenesis, inflammatory cell recruitment and reaction, the growth of endometriotic tissue and its survival through the modulation of the narrow immune system. This review will evaluate the role played by several regulatory peptides, proteins and growth factors in affecting endometrial physiology and the putative mechanisms advocated to explain endometriosis (angiogenesis, cellular and humoral immunity, inflammatory response, endometrial cell proliferation, activation, motility, adhesion and invasion).

Deregulation of LOXL1 and HTRA1 gene expression in endometriosis

Endometriosis is a gynecologic disease characterized by the presence of endometrial tissue outside the uterine cavity. Although 15% of the female population in reproductive age is affected by endometriosis, its pathogenesis remains unclear. According to the most accepted pathogenesis hypothesis, endometrial fragments from the menstrual phase are transported through the uterine tubes to the peritoneal cavity, where they undergo implantation and growth, invading adjacent tissues. However, the establishment of the disease requires that endometrial cells present molecular characteristics favoring the onset and progression of ectopic implantation. In this investigation, we analyzed the differential gene expression profiles of peritoneal and ovarian endometriotic lesions compared to the endometrial tissue of nonaffected women using rapid subtraction hybridization (RaSH). In our study, this method was applied to samples of endometriotic lesions from affected women and to biopsies of endometrium of healthy women without endometriosis, where we could identify 126 deregulated genes. To evaluate the expression of genes found by RaSH method, we measured LOXL1, HTRA1, and SPARC genes by real-time polymerase chain reaction. Significant different expression was obtained for HTRA1 and LOXL1, upregulated in the ectopic endometrium, suggesting that these genes are involved in the physiopathology of endometriosis and may favor the viability of endometrial cells at ectopic sites.

The role of iron in the pathogenesis of endometriosis

BACKGROUND

Endometriosis may cause symptoms including chronic pelvic pain and infertility, and increases susceptibility to the development of ovarian cancer. Genomic studies have started to delineate the wide array of mediators involved in the development of endometriosis. Understanding the mechanisms of endometriosis development and elucidating its pathogenesis and pathophysiology are intrinsic to prevention and the search for effective therapies.

METHOD OF STUDY

The present article reviews the English language literature for biological, pathogenetic and pathophysiological studies on endometriosis. Several recent genomic studies are discussed in the context of endometriosis biology.

RESULTS

Severe hemolysis occurring during the development of endometriosis results in high levels of free heme and iron. These compounds oxidatively modify lipids and proteins, leading to cell and DNA damage, and subsequently fibrosis development. Recent studies based on genome-wide expression analysis technology have noted specific expression of heme/iron-dependent mediators in endometriosis. The heme/iron-dependent signaling pathway of endometriosis, which is providing new insights into the regulation of inflammation, detoxification and survival, is discussed.

CONCLUSION

Several important endometriosis-specific genes overlap with those known to be regulated by iron. Other genes are involved in oxidative stress. Iron has a significant impact on endometriotic-cell gene expression. This review summarizes recent advances in the heme/iron-mediated signaling and its target genes, outlines the potential challenges to understanding of the pathogenesis and pathophysiology of endometriosis, and proposes a possible novel model.

Expression of heparanase and angiopoietin-2 in patients with endometriosis

OBJECTIVE

The objective was to investigate the expression of heparanase (Hpa) and angiopoietin-2 (Ang-2) in endometriosis.

STUDY DESIGN

In ectopic and eutopic endometrium of patients undergoing laparoscopy for endometriosis (n=86) and in normal endometrium of patients undergoing laparoscopic tubal ligation or hysteroscopic resection because of uterus septus (n=30), we determined Hpa and Ang-2 gene expression by RT-PCR. To support the mRNA data, the expression of Hpa and Ang-2 protein was measured by Western blot analysis. Finally, Hpa and Ang-2 in these tissues was localized by immunohistochemical staining.

RESULT(S)

The positive rate of Hpa and Ang-2 mRNA in ectopic and eutopic endometrium in the study group was significantly higher than that in normal endometrium in the control group. In the study group, ectopic and eutopic endometrium expressed a higher positive rate of Hpa and Ang-2 protein, whereas in the control group, normal endometrium expressed a lower positive rate of Hpa and Ang-2 protein. In eutopic and ectopic endometrium, there was balanced expression between Hpa and Ang-2. Both Hpa and Ang-2 showed a balanced expression between eutopic and ectopic endometrium. In ectopic endometrium, strong staining for Hpa and Ang-2 was observed both in epithelial cells and in stromal cells, but in eutopic endometrium, Hpa and Ang-2 were mainly expressed in epithelial cells.

CONCLUSION

The higher expression of Hpa and Ang-2 in ectopic and eutopic endometrium may play an important role in the pathogenesis and development of endometriosis.

Expression of angiogenic factors in endometriosis: relationship to fibrinolytic and metalloproteinase systems

BACKGROUND

Endometriosis is a highly prevalent, benign disease in which the angiogenic, fibrinolytic and metalloproteinase (MMP) systems may be implicated. The objective of this study is to analyse mRNA expression and protein levels of several angiogenic factors and to correlate them with several components of the fibrinolytic and MMP systems in samples from 71 women with endometriosis and 50 controls.

METHODS AND RESULTS

Eutopic endometrium showed higher mRNA expression of vascular endothelial growth factor (VEGF) in patients than in controls. However, ovarian endometrioma had lower VEGF mRNA levels than did the eutopic endometrium of patients. Similar results were obtained for VEGF protein levels. On the other hand, a significant increase in thrombospondin-1 (TSP-1) levels was observed in ovarian endometrioma than in eutopic endometrium. The peritoneal fluid from women with endometriosis showed a significant increase in VEGF, urokinase-type plasminogen activator (uPA) and MMP-3 levels than that of controls. A significant correlation was observed between the levels of VEGF and uPA in endometrium and in peritoneal fluid.

CONCLUSIONS

Endometrium and peritoneal fluid from women with endometriosis have increased levels of VEGF, uPA and MMP-3 levels. Therefore, the development of endometriotic implants at ectopic sites may be facilitated, promoting the progress of the endometriosis.

Insulin-like growth factor-1 isoform mRNA expression in women with endometriosis: eutopic endometrium versus endometriotic cyst

Pathogenesis of endometriosis involves growth factors, which are synthesized locally. Insulin-like growth factor-1 (IGF-1) prevents apoptosis and has mitogenic action on endometrial cells. The IGF-1 gene undergoes alternative splicing and results in three isoforms (IGF-1Ea, IGF-1Eb, and IGF-1Ec or MGF). We analyzed the mRNA expression of IGF-1 isoforms in tissue samples of eutopic endometrium and endometriotic cyst obtained during laparoscopy from women with endometriosis. We documented that all three IGF-1 isoforms are expressed in both eutopic endometrium and ovarian endometrioma. Furthermore, we documented a significant decrease in all IGF-1 isoform expression in endometriotic cyst compared to endometrium of women with endometriosis. The reduction may correlate with the disease status and presence of fibrotic inactive tissue found in late stages of the disease.

mRNA analysis of several components of the plasminogen activator and matrix metalloproteinase systems in endometriosis using a real-time quantitative RT-PCR assay

BACKGROUND

The plasminogen activator (PA) and matrix metalloproteinase (MMP) systems are implicated in the establishment of endometriosis. The mechanisms by which these systems are involved in the pathogenesis of this disease are not well defined and controversial results have been published. The aim of this study was to analyse mRNA and protein levels of several components of the PA and MMP systems in endometriotic tissue and endometrium from women with and without endometriosis.

METHODS AND RESULTS

Real-time quantitative RT-PCR assays were developed to quantify mRNA levels of these components in 57 women with endometriosis and 32 controls. Endometrium of women with endometriosis showed higher mRNA and antigenic levels of urokinase type-PA (uPA) and MMP-3 than endometrium from controls. In these patients, ovarian endometriotic tissue had higher mRNA and antigenic levels of PA inhibitor type 1 (PAI-1) and MMP inhibitor type 1 (TIMP-1) than endometrium.

CONCLUSIONS

The increase in mRNA and protein levels of uPA and MMP-3 observed in endometrium of women with endometriosis may facilitate the attachment of endometrial tissue to the peritoneum and ovarian surface, as well as the invasion of the extracellular matrix. This process would lead to the formation of early endometriotic lesions. Once the ovarian endometriotic cyst is developed, PAI-1 and TIMP-1 would increase which could explain the frequent clinical finding of an endometrioma without invasion of the adjacent ovarian tissue.