Menstrual endometrial cells from women with endometriosis demonstrate increased adherence to peritoneal cells and increased expression of CD44 splice variants

Abstract

Objective: We previously demonstrated that adherence of endometrial epithelial (EECs) and stromal cells (ESCs) to peritoneal mesothelial cells (PMCs) is partly regulated by ESC/EEC CD44 interactions with PMC associated hyaluronan. CD44, a transmembrane glycoprotein and major ligand for hyaluronan, has numerous splice variants which may impact hyaluronan binding. Here, we assessed whether ESCs and EECs from women with endometriosis demonstrate increased adherence to PMCs and examined CD44 splice variants' potential role in this process.

Design: In vitro study.

Setting: Academic medical center.

Patient(s): Fertility patients with and without endometriosis.

Intervention(s): Menstrual endometrium was collected from women with and without endometriosis confirmed surgically. The adherence of ESC/EECs to PMCs was measured. The ESC/EEC CD44 splice variants were assessed using dot-blot analysis.

Result(s): The ESCs and EECs from women with endometriosis demonstrated increased adherence to PMCs. The predominant CD44 splice variants expressed by ESCs and EECs from women with and without endometriosis were v3, v6, v7, v8, v9, and v10. The ESCs and EECs from women with endometriosis were more likely to express v6, v7, v8, and v9.

Conclusion(s): Increased eutopic endometrial-PMC adherence and CD44 splice variant expression may contribute to the histogenesis of endometriotic lesions. Elucidation of factors controlling this expression may lead to novel endometriosis therapies.

Figure 1

An increased proportion of ESCs and EECs from women with endometriosis adhered to LP9 PMCs compared with ESCs and EECs from controls (43 % versus 32 and 23% versus 15%, respectively) (* p<0.002, ** p =0.07).

Figure 2

Representative dot blot array hybridization of endometrial epithelial cells from a woman with endometriosis. Hybridization with specific splice variants showing v3, v6, v8, v9, and v10 (dark solid circles). Splice variants v2, v4, v5, and v7 are not expressed (dark dashed circles). Negative controls consisted of non-specific oligonucleotide sequences (white dashed circle). Positive controls are exon 5 and 17 from the non-variable region of CD44 (white solid circles).