Exosomal miR-214 from endometrial stromal cells inhibits endometriosis fibrosis

Is it possible to improve fibrosis in endometriosis by microRNA-214 delivery in exosomes? Upregulation of miR-214 may inhibit fibrogenesis and its delivery by exosomes derived from ectopic endometrial stromal cells (ESCs), offers an alternative therapeutic approach for endometriosis fibrosis. Fibrosis is the primary pathological feature of endometriosis. MiR-214 plays an important role in fibrotic disease. Connective tissue growth factor (CTGF) is a critical fibrogenic mediator of miR-214. The expression of miR-214 is decreased in ectopic ESCs compared with normal ESCs. miRNAs are a natural cargo of exosomes and these could be exploited as carriers of miRNA in replacement therapy. Paired eutopic and ectopic endometrial tissue samples were obtained from 10 women with ovarian endometrioma. ESCs and epithelial cells from both were cultured in vitro. RT-PCR, western blot and immunohistochemistry were used to study the effect of transfection with miR-214 mimics on CTGF expression and fibrogenesis respectively, with and without TGFβ stimulation. Exosomes were isolated from ectopic ESCs and Endometrioma tissue was isolated from four patients, dispersed an injected (ip) into nude mice and allowed to implant. The mice were treated with miR-214-enriched exosomes or controls to confirm the effect of inhibiting CTGF overexpression on endometriosis fibrosis. The primary ectopic ESCs were transfected with miR-214 mimics. The levels of miR-214, CTGF and fibrotic markers were measured by RT-PCR and Immunohistochemistry. A mouse model of endometriosis was established by ip injection of human ectopic endometrial tissues into nude mice. MiR-214-enriched exosomes were injected into the mice and endometriotic lesions were measured on Day 28. Changes in fibrosis of the endometriotic implants were studied by histopathological staining. CTGF and fibrotic markers upregulation in endometriosis is associated with a reciprocal down-regulation of miR-214. By using miR-214 mimics and antagomirs to investigate expression of fibrotic markers, we found that increased production of miR-214 reduced Collagen αI and CTGF expression in endometriosis stromal and endometrial epithelial cells in response to fibrosis-inducing stimuli (P < 0.001 versus non-treatment). Ectopic ESCs yielded nano-sized exosomes which expressed miR-214. Loading exosomes with miR-214 mimics and injecting them into an experimental endometriosis mouse model resulted in a decrease in the expression of fibrosis-associated proteins (P < 0.001 versus PBS control group). N/A. We only isolated exosomes from ectopic ESCs, whether this is the optimum source requires further study. Upregulation of miRNA-214 potentially offers an alternative therapeutic approach for endometriosis fibrosis. This work was supported by grants from the National Natural Science Foundation of China (Grant no. 81771549 Jinwei Miao). The authors declare that there is no conflict of interest.