[The high expression of decorin in decidua of patients with missed abortion and inhibitory mechanism of decorin on the M1 macrophages polarization derived from peripheral blood mononuclear cells].

Objective To explore the alterations in macrophage polarization and the expression of decorin (DCN) protein in the decidua of patients with missed abortion (MA), as well as to elucidate the regulatory effect of DCN on macrophage polarization. Methods Flow cytometry was employed to assess the polarization ratio of decidual macrophages in MA, recurrent spontaneous abortion (RSA) and normal pregnancy (NP); The expression and localization of DCN and hypoxia-inducible factor 1α (HIF-1α) in decidua and villi were assessed by immunohistochemistry staining, while their protein levels were measured by Western blot. Primary trophoblasts and peripheral blood mononuclear cell (PBMC)-derived macrophages were isolated and cultured. ELISA was conducted to quantify DCN levels in the culture supernatant of primary trophoblast and PBMC-derived macrophages. Additionally, flow cytometry was applied to evaluate the polarization ratio of PBMC-derived macrophages. Immunofluorescence cytochemical staining was conducted to examine HIF-1α expression in macrophages. Western blot was performed to detect the expression of proteins related to the gene associated with retinoid-IFN-induced mortality 19 (GRIM-19)/signal transducer and activator of transcription 3 (STAT3)/HIF-1α signaling pathway in macrophages. Results The polarization ratio of M1 macrophages in the decidua of abortion patients was significantly higher than that of NP, whereas the ratio of M2 macrophages was significantly lower. The expression of DCN and HIF-1α protein were significantly evaluated in abortion patients compared to NP. The supernatant DCN content and HIF-1α protein expression of primary trophoblast and PBMC-derived macrophages cultured under 10 mL/L O2 for 24 hours were markedly increased compared to cells treated with 210 mL/L O2. Compared with the PBS group, the proportion of M1 macrophage and GRIM-19 protein expression were significantly reduced in the DCN group, while phosphorylated STAT3 (p-STAT3) and HIF-1α protein expression were significantly increased. Conclusion The expression of DCN in decidua and villi of MA is higher than that of NP. DCN exhibits an inhibitory effect on the M1 polarization of PBMCs-derived macrophages, which is likely mediated through the GRIM-19/STAT3/HIF-1α signaling pathway.