Peritoneal fluid from subjects with endometriosis regulates gene expression in cultured endometrial cells

Purpose: This study was undertaken to evaluate the effect of peritoneal fluid from subjects with differing stages of endometriosis on gene expression in endometrial stromal cells. Methods: Peritoneal fluid from subjects with minimal, moderate, and severe stages of endometriosis or without endometriosis (controls) was collected, filtered and separated from peritoneal cells. Telomerase – immortalized human endometrial stromal cells (T-HESC) were treated with the peritoneal fluid samples for 48 hours. RNA was isolated from treated cells and processed for DNA microarray. Results: 162 genes were found to be differentially expressed in T-HESC cells treated with peritoneal fluid from subjects with differing stages of endometriosis. Three of the differentially expressed genes were chosen for confirmatory studies using quantitative RT-PCR; these were interleukin 8, corin and matrix metalloproteinase 3. The primary gene ontologies identified by microarray highlight functions expected to be involved in the establishment of endometriosis, such as proteases, signal transduction, defense and immune system, cell adhesion, cell cycle and cell death, cytoskeleton, transcriptional regulation and translation, extracellular matrix, and enzymes and metabolism. Conclusions: This study demonstrated that the severity of endometriosis affected the factors present in peritoneal fluid which, in turn, affected gene expression in endometrial stromal cells. Peritoneal fluid from 12 individual subjects was used to treat T-HESC cells. Subjects were grouped by absence (controls, n=3) or presence of endometriosis. Subjects with endometriosis were divided into 3 groups: minimal, moderate, or severe endometriosis. Experimental number was 3 per group. The 12 samples were analyzed on individual microarrays.