Endometriosis is a common chronic gynecological disease that affects up to 10% of women of reproductive age. It is characterized by the presence of endometrium outside the uterine cavity, causing various symptoms, such as infertility and chronic pain. The gold standard for its diagnosis is still laparoscopy and the biopsy of endometriotic lesions due to the absence of non-invasive diagnostic tools. Here, we aimed to compare the eutopic endometrium from women with or without endometriosis to identify proteins that may play a role in the etiology of endometriosis and thus be considered as potential biomarker candidates, calling for further targeted studies.
Eutopic endometrium was collected from patients with endometriosis and women without endometriosis during a laparoscopy surgery between days 19 and 24 of their menstrual cycle (mid-secretory phase). Total proteins from tissues were extracted and digested with trypsin before LC-MS-MS analysis in a data-dependent acquisition mode on a TimsTOF Pro instrument. Data were evaluated using bioinformatics tools and integrated to previously published data.
Among the 5,301 proteins identified, 543 were differentially expressed. This global differential signature allowed us to separate directly the controls from the endometriosis samples. Interestingly differential proteins were enriched in two specific KEGG pathways: focal adhesion and PI3K/AKT signaling. Integration of our data with a yet unpublished large-scale proteomics dataset allowed us to highlight 11 proteins that share the same trend of dysregulation in eutopic endometrium, regardless of the phase of the menstrual cycle, whereas 16 proteins were identified as being overexpressed in the serum of women with endometriosis.
Our results constitute a first milestone towards the identification of potential promising endometrial and serological diagnostic biomarkers. They provide new insights into the mechanisms underlying endometriosis and its etiology. Our results need further confirmation on a larger sample cohort. Data are available via ProteomeXchange with the identifier PXD012981.