miR-196b-5p Affects Macrophage Polarization and Inflammation in Endometriosis.

Background: miR-196b-5p was found to be significantly reduced in endometriosis, but its function and the mechanisms involved remained unclear.

Objective: To explore the effect of miR-196b-5p on manipulating macrophage phenotype and the underlying mechanisms in endometriosis.

Methods: The endometriosis mice and End1/E6E7 cells were used for in vivo and in vitro experiments, respectively. QRT-PCR was used to detect miR-196b-5p, suppressor of cytokine signaling 1 (SOCS1), high mobility group AT-Hook 1 (HMGA1), and CCL2 expressions. Western blot was used to detect SOCS1 and HMGA1 protein levels while luciferase reporter assay was performed to determine the interaction between miR-196b-5p and SOCS1/ HMGA1. ELISA was used to measure CCL2, IL-10, and IL-6 levels and immunohistochemical staining and flow cytometry were used to examine CD86 and CD206 expressions.

Results: Significantly reduced levels of miR-196b-5p, and increased levels of SOCS1, HMGA1, and CCL2 were observed in the ectopic endometrium of mice with endometriosis. The miR-196b-5p mimic significantly reduced the lesion size, increased M1 macrophages, and decreased M2 macrophages in the ectopic endometrium of mice with endometriosis. End1/E6E7 cells transfected with miR196b-5p mimic significantly increased M1 macrophages, decreased M2 macrophages and reduced the migration in PMA-treated THP1 cells. Conversely, transfection with a miR-196b-5p inhibitor led to the opposite outcomes. miR-196b-5p targeted SOCS1/HMGA1, and miR-196b-5p inhibitor significantly up-regulated CCL2 and IL-10, and down-regulated IL-6 levels in End1/E6E7 cells. These effects were markedly reversed by si-SOCS1/si-HMGA1.

Conclusion: miR-196b-5p elevates M1 macrophages and decreases M2 macrophages in endometriosis, possibly by targeting SOCS1/ HMGA1. This research may provide a novel insight into the pathological mechanisms of endometriosis.