Extracellular vesicles contribute to EMT in adenomyosis by inducing macrophage polarization

Adenomyosis is a benign disease, but it exhibits a metastatic property similar to tumors. Its pathogenesis is still unclear. One theory is that adenomyosis is the result of epithelial-mesenchymal transition (EMT) in displaced embryonic Muller cells. Macrophages accumulate in the eutopic endometrium of adenomyosis and play an important role in EMT and the pathogenesis of adenomyosis. Extracellular vesicles (EVs) are considered an important mechanism of intercellular communication, but few studies have shown the role of EVs between endometrial epithelial cells and macrophages. In this study, we collected the eutopic endometrium of adenomyosis, and acquired the primary endometrial cells, then isolated EVs from the culture supernatants. We identified the characteristics of EVs by transmission electron microscopy, nanoparticle tracking, and western blot, and then detected the mRNA expression levels of CD163, IL-10, iNOS, and TNF-α in macrophages by qRT-PCR after co-cultured with EVs; the expression levels of E-cadherin, CK7, N-cadherin, and Vimentin by Western blot, and the migration abilities of epithelial cells by Transwell assay. The results showed that macrophages were highly expressed in the mRNA levels of CD163, IL10, and TNF-α after treated by EVs from adenomyosis patients; endometrial epithelial cells expressed lower protein levels of E-cadherin and CK7, higher levels of N-cadherin and Vimentin after co-cultured with the above polarized macrophages; and the migration abilities of epithelial cells were enhanced. In conclusion, EVs derived from adenomyosis can induce macrophages to polarize toward M2b, and the polarized macrophages could, in turn, induce EMT process in endometrial epithelial cells.