Host-Derived TGFB1 Deficiency Suppresses Lesion Development in a Mouse Model of Endometriosis

Antifibrotic properties of epigallocatechin-3-gallate in endometriosis

STUDY QUESTION

Is epigallocatechin-3-gallate (EGCG) treatment effective in the treatment of fibrosis in endometriosis?

SUMMARY ANSWER

EGCG appears to have antifibrotic properties in endometriosis.

WHAT IS KNOWN ALREADY

Histologically, endometriosis is characterized by dense fibrous tissue surrounding the endometrial glands and stroma. However, only a few studies to date have evaluated candidate new therapies for endometriosis-associated fibrosis.

STUDY DESIGN, SIZE, DURATION

For this laboratory study, samples from 55 patients (45 with and 10 without endometriosis) of reproductive age with normal menstrual cycles were analyzed. A total of 40 nude mice received single injection proliferative endometrial fragments from a total of 10 samples.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The in vitro effects of EGCG and N-acetyl-l-cysteine on fibrotic markers (alpha-smooth muscle actin, type I collagen, connective tissue growth factor and fibronectin) with and without transforming growth factor (TGF)-β1 stimulation, as well as on cell proliferation, migration and invasion and collagen gel contraction of endometrial and endometriotic stromal cells were evaluated by real-time PCR, immunocytochemistry, cell proliferation assays, in vitro migration and invasion assays and/or collagen gel contraction assays. The in vitro effects of EGCG on mitogen-activated protein kinase (MAPK) and Smad signaling pathways in endometrial and endometriotic stromal cells were evaluated by western blotting. Additionally, the effects of EGCG treatment on endometriotic implants were evaluated in a xenograft model of endometriosis in immunodeficient nude mice.

MAIN RESULTS AND THE ROLE OF CHANCE

Treatment with EGCG significantly inhibited cell proliferation, migration and invasion of endometrial and endometriotic stromal cells from patients with endometriosis. In addition, EGCG treatment significantly decreased the TGF-β1-dependent increase in the mRNA expression of fibrotic markers in both endometriotic and endometrial stromal cells. Both endometriotic and endometrial stromal cell-mediated contraction of collagen gels were significantly attenuated at 8, 12 and 24 h after treatment with EGCG. Epigallocatechin-3-gallate also significantly inhibited TGF-β1-stimulated activation of MAPK and Smad signaling pathways in endometrial and endometriotic stromal cells. Animal experiments showed that EGCG prevented the progression of fibrosis in endometriosis.

LIMITATIONS, REASONS FOR CAUTION

The attractiveness of epigallocatechin-3-gallate as a drug candidate has been diminished by its relatively low bioavailability. However, numerous alterations to the EGCG molecule have been patented, either to improve the integrity of the native compound or to generate a more stable yet similarly efficacious molecule. Therefore, EGCG and its derivatives, analogs and prodrugs could potentially be developed into agents for the future treatment and/or prevention of endometriosis.

WIDER IMPLICATIONS OF THE FINDINGS

Epigallocatechin-3-gallate is a potential drug candidate for the treatment and/or prevention of endometriosis.

STUDY FUNDING/COMPETING INTERESTS

This study was supported in part by Karl Storz Endoscopy & GmbH (Tuttlingen, Germany). No competing interests are declared.

Differential TGFB1-Signalling in Endometrium from Women with Endometriosis: Importance of Appropriate Housekeeping Genes

Purpose

Endometriosis is characterised by inflammation, fibrosis and scarring, all processes known to involve transforming growth factor-β1 (TGFB1). We examined the expression of genes involved in TGFB1 signalling in epithelium and stroma from eutopic versus ectopic endometrium in women with endometriosis.

Methods

Eutopic and ectopic endometrium was collected during laparoscopy from women with endometriosis (n = 4 proliferative, n = 7 secretory). Laser capture microdissection was used to collect glandular epithelium and CD10-positive stroma from ectopic lesions and eutopic endometrium. Quantitative real-time RT-PCR was used to examine TGFB1, SMAD family member-2 (SMAD2), SMAD3 and SMAD4 mRNA. Expression of mRNA was relative to an RNA-spike. B2M and RPL13A mRNA, and 18S rRNA were also examined; however, expression varied between eutopic and ectopic sites making them unsuitable housekeeping genes in this model.

Results

TGFB1, SMAD3 and SMAD4 mRNA expression was significantly higher in eutopic versus ectopic glandular epithelium; SMAD3 expression was significantly higher in secretory versus proliferative phase eutopic epithelium. TGFB1 expression was significantly higher in eutopic versus ectopic stroma.

Conclusions

Variations in TGFB1, SMAD3 and SMAD4 mRNA expression in eutopic relative to ectopic tissues are consistent with a specific function in eutopic endometrium not replicated in lesions. We suggest that TGFB1-mediated activity is altered in ectopic lesions relative to eutopic endometrium in women with endometriosis, which may affect lesion maintenance. Further research examining the functional consequences of TGFB1 signalling variations is required, including extension of these studies to women without the disorder. Further studies must also carefully consider their housekeeping method and its impact on data and conclusions.

Involvement of the Wnt/β-catenin signaling pathway in the cellular and molecular mechanisms of fibrosis in endometriosis

Background

During the development and progression of endometriotic lesions, excess fibrosis may lead to scarring, chronic pain, and altered tissue function. However, the cellular and molecular mechanisms of fibrosis in endometriosis remain to be clarified.

Objectives

The objective of the present study was to investigate whether the Wnt/β-catenin signaling pathway was involved in regulating the cellular and molecular mechanisms of fibrosis in endometriosis in vitro and to evaluate whether fibrosis could be prevented by targeting the Wnt/β-catenin pathway in a xenograft model of endometriosis in immunodeficient nude mice.

Methods

Seventy patients (40 with and 30 without endometriosis) with normal menstrual cycles were recruited. In vitro effects of small-molecule antagonists of the Tcf/β-catenin complex (PKF 115-584 and CGP049090) on fibrotic markers (alpha smooth muscle actin, type I collagen, connective tissue growth factor, fibronectin) and collagen gel contraction were evaluated in endometrial and endometriotic stromal cells from patients with endometriosis. In vitro effects of activation of the Wnt/β-catenin signaling pathway by treatment with recombinant Wnt3a on profibrotic responses were evaluated in endometrial stromal cells of patients without endometriosis. The effects of CGP049090 treatment on the fibrosis of endometriotic implants were evaluated in a xenograft model of endometriosis in immunodeficient nude mice.

Results

Treatment with PKF 115-584 and CGP049090 significantly decreased the expression of alpha smooth muscle actin, type I collagen, connective tissue growth factor and fibronectin mRNAs in both endometriotic and endometrial stromal cells with or without transforming growth factor-β1 stimulation. Both endometriotic and endometrial stromal cell-mediated contraction of collagen gels was significantly decreased by treatment with PKF 115-584 and CGP049090 as compared to that of untreated cells. The animal experiments showed that CGP049090 prevented the progression of fibrosis and reversed established fibrosis in endometriosis.

Conclusion

Aberrant activation of the Wnt/β-catenin pathway may be involved in mediating fibrogenesis in endometriosis.

Endometriosis, a disease of the macrophage

Endometriosis, a common cause of pelvic pain and female infertility, depends on the growth of vascularized endometrial tissue at ectopic sites. Endometrial fragments reach the peritoneal cavity during the fertile years: local cues decide whether they yield endometriotic lesions. Macrophages are recruited at sites of hypoxia and tissue stress, where they clear cell debris and heme-iron and generate pro-life and pro-angiogenesis signals. Macrophages are abundant in endometriotic lesions, where are recruited and undergo alternative activation. In rodents macrophages are required for lesions to establish and to grow; bone marrow-derived Tie-2 expressing macrophages specifically contribute to lesions neovasculature, possibly because they concur to the recruitment of circulating endothelial progenitors, and sustain their survival and the integrity of the vessel wall. Macrophages sense cues (hypoxia, cell death, iron overload) in the lesions and react delivering signals to restore the local homeostasis: their action represents a necessary, non-redundant step in the natural history of the disease. Endometriosis may be due to a misperception of macrophages about ectopic endometrial tissue. They perceive it as a wound, they activate programs leading to ectopic cell survival and tissue vascularization. Clearing this misperception is a critical area for the development of novel medical treatments of endometriosis, an urgent and unmet medical need.