Establishing an Endometriosis Transcriptomic cell atlas to decipher the physiopathological role of stem cells and estrogen in the disease – EDISON

Endometriosis is a chronic estrogen-dependent inflammatory gynecological disease that affects nearly 10% of women of childbearing age and up to 40% of infertile women, with diagnosis wandering of 6 to 10 years. Endometriosis is defined as the presence of endometrial tissue outside the uterus. Women with endometriosis suffer from severe pelvic pains, which impact their quality of life and have a significant economic and societal impact. So-called estrogen-suppressive hormone therapies are the first line of treatments, because estrogens play a key role in the pathophysiology of endometriosis. However, these hormonal treatments, which are not without side effects, do not allow optimal control of the disease or recurrence, despite the surgery often associated with them. It is therefore necessary to improve diagnostic and therapeutic strategies for endometriosis.
The most widely accepted hypothesis to explain the formation of endometriotic lesions is the tubal retrograde reflux during menstruation. However, only 10% of the reproductive-aged women will develop endometriosis while 90% of women experience retrograde menstruation. This raises the question of the stem cells present in the endometrium and menstrual reflux (peritoneal fluid) of these patients, and if stem cells in the menstruations from endometriosis patients are different from the ones of healthy women. Moreover, a number of studies highlight changes in the microenvironment (lesional immune cells, peritoneal fluid,…) which seems to be crucial for the proliferation of ectopic endometrial cells as cells attach, escape to apoptosis and immunosurveillance, creating a new ectopic niche to survive.
In this project, we will test the hypothesis that, at the crucial time of shedding (menstruation), endometriosis could thus result, at least in part, from differences,compared to controls, in : A) number and/or phenotype of stem cells harvested in the peritoneal fluid, and (B) peculiar immune cells profile in the peritoneal fluid at the time of shedding and (C) soluble factors of the peritoneal fluid; altogether concurring to the implantation and/or development of lesions.
To this aim, the EDISON project will collect peritoneal fluid, endometrium and endometriotic lesions from patients operated for endometriosis at the key time of menstruation, and peritoneal fluid and endometrium from patients without endometriosis.
Our three main objectives are:
1) To characterize cellular heterogeneity between eutopic endometrium and ectopic lesions in parallel with peritoneal fluid to identify potential stem cells and the immune microenvironment (using a combination of unbiased transcriptomic, spectral flow cytometry and multiplex imaging analysis)
2) To develop a biobank of organoid models derived from cells collected on peritoneal fluid and tissue biopsies at the time of menstruation, that integrate peritoneal fluid factors (supernatant and/or cells) to clarify stem cell properties/characteristics and their supportive environment
3) To leverage the use of these endometrial derived-organoids to functionally characterize estrogen signaling in women with or without endometriosis
The ambition of this multidisciplinary approach is to better understand the pathophysiology of endometriosis, which was largely underexplored and poorly understood until now due to its complexity and the lack of relevant animal models. This project will lead to the characterization of specific cells and the peritoneal microenvironment at the time of menstruation in order to identify potential biomarkers and to orient research towards new personalized diagnostic and therapeutic strategies. The identification of new treatments for endometriosis in these women will ultimately have an impact on quality of life and potential infertility, reducing the medical and societal costs associated with this disease.