Spatial Transcriptomic Analysis of Superficial Peritoneal Endometriotic Lesions

The mechanisms underlying the pathophysiology of endometriosis, characterized by the presence of endometrium-like tissue outside the uterus, remain poorly understood. This study aimed to identify cell type-specific gene expression changes in superficial peritoneal endometriotic lesions and elucidate the crosstalk among the stroma, epithelium, and macrophages compared to patient-matched eutopic endometrium. Surprisingly, comparison between lesions and eutopic endometrium revealed transcriptional similarities, indicating minimal alterations in the sub-epithelial stroma and epithelium of lesions. Spatial transcriptomics (NanoString GeoMx) highlighted increased signaling between the lesion epithelium and macrophages, emphasizing the role of the epithelium in driving lesion inflammation. We propose that the superficial endometriotic lesion epithelium orchestrates inflammatory signaling and promotes a pro-repair phenotype in macrophages, providing a new role for Complement 3 in lesion pathobiology. This study underscores the significance of considering spatial context and cellular interactions in uncovering mechanisms governing disease in endometriotic lesions. Superficial peritoneal lesions and eutopic uterine tissue were collected from five women in the secretory phase of the menstrual cycle. Matched lesion and eutopic tissues (n = 10) were selected. Duplicate regions of interest were selected for each tissue and segmented based on fluorescence intensity for macrophages (marker: CD68+), epithelium (marker: pan-cytokeratin+), and stroma (marker: ACTA2-, CD68-, pan-cytokeratin-), resulting in 60 segments/AOI (area of illumination).