Mapping Decidualization Resistance in Former Severe Preeclampsia Patients at Multi-Omic Levels

Endometrial decidualization resistance (DR) is implicated in various gynaecological and obstetric conditions. Employing a multi-omic strategy, we unraveled the cellular and molecular characteristics of DR in patients that have suffered severe preeclampsia (sPE). Morphological analysis unveiled significant glandular anatomical abnormalities, confirmed histologically. Single-cell RNA sequencing (scRNA-seq) of endometrial samples from sPE cases (n=11) and controls (n=12) revealed sPE-associated shifts in cell composition, manifesting as a stromal mosaic state characterized by proliferative stromal cells (MMP11, SFRP1+) alongside IGFBP1+ decidualized cells, with concurrent epithelial mosaicism and a dearth of epithelial-stromal transition associated with decidualization. Cell-cell communication network mapping underscored aberrant crosstalk among specific cell types, implicating crucial pathways such as endoglin and WNT. Spatial transcriptomics in a replication cohort validated DR-associated features. Laser capture microdissection/mass spectrometry in a second replication cohort corroborated several scRNA-seq findings, notably the absence of stromal to epithelial transition at a pathway level, indicating disrupted response to steroid hormones, particularly estrogens. These insights shed light on potential molecular mechanisms underpinning DR pathogenesis in the context of sPE. A total of 23 non-pregnant women who had a previous pregnancy were enrolled in this study for single-cell RNA-Sequencing analysis. From those, 12 were women with a healthy previous pregnancy as control cases and 11 were women diagnosed with Severe Preeclampsia in their last pregnancy clinically classified based the ACOG guidelines: high blood pressure (systolic > 160 or diastolic > 100 mmHg) or thrombocytopenia, impaired liver function, progressive renal insufficiency, pulmonary edema, or the inset cerebral or visual disturbances. Endometrial biopsies were collected during the late secretory phase of the menstrual cycle (1 to 3 days before menstruation) and tissue were segmented in different portions, one of the were embedded in paraffin to obtain histological sections for the spatial transcriptomics approach, other section were included in OCT for the laser capture and mass spectrometry approach and another portion was processed to obtain the cell isolation that will be used to the single-cell RNA sequencing using 10X genomics technologies. The maternal parameters were recruited in the Supplementary table 1. A two tailed Student’s T-test was applied between sPE and Control variables based on the normal distribution of data. *** Submitter states "we are unable to upload the raw sequences to a public database, as they originate from living donors. Once the publication is approved for release, we will proceed to upload the raw sequence data to a managed access database"***