Exosomes from chronic endometritis (CE) affect trophoblast adhesion, migration and invasion

To assess whether chronic endometritis (CE) affects decidualization of human endometrial stromal cells (ESCs) and to investigate whether Exosomes (Exos) secreted by ESCs from patients with CE impair trophoblast adhesion, invasion and migration. ESCs were isolated from endometrial samples from 15 patients with CE and 15 patients without CE(non-CE, NCE) and cultured separately in vitro. The expression levels of inflammatory cytokines in primary ESCs were measured by quantitative real-time polymerase chain reaction (qRT-PCR). ESCs at passage 3 (3°-ESCs) were subjected to in vitro decidualization for 5 days. Thereafter, the mRNA expression levels of PRL and IGFBP1 were measured by qRT-PCR, and PRL concentrations in the culture supernatants were quantified using chemiluminescent immunoassay(CLIA). Exos were isolated from the culture supernatants of 3°-ESCs by ultracentrifugation. Wound-healing, cell-invasion, and modified trophoblast spheroid-adhesion assays were performed to evaluate the effects of CE-derived exosomes on implantation-related trophoblast functions. Primary ESCs from the CE group exhibited significantly higher expression levels of IL-1β, IL-8, and TNF-α than those from the NCE group. Following 5 days of in vitro decidualization, 3°-ESCs from the CE group showed impaired decidualization, as indicated by lower cell numbers and reduced expression and secretion of the decidualization markers PRL and IGFBP1 compared with the NCE group. Exos isolated from ESCs exhibited a typical lipid bilayer structure, with a mean diameter of 153.7 nm and expression of the exosomal marker CD81. Exos from both groups were internalized by HTR8/SVneo trophoblast spheroids within 2 h. Compared with NCE-derived Exos, CE-derived Exos significantly reduced the migratory and invasive capacities of HTR8/SVneo cells and decreased the attachment rate of HTR8/SVneo spheroids. Notably, high-mobility group box 1 (HMGB1) was detected only in CE-Exos. Pharmacological inhibition of HMGB1 with glycyrrhizic acid partially rescued CE-Exos-induced reductions in HTR8/SVneo cell invasion and trophoblast spheroid attachment. These findings support the involvement of exosomal HMGB1 in CE-associated trophoblast dysfunction. CE impairs the decidualization of human ESCs. Moreover, Exosomes derived from ESCs of patients with CE reduce trophoblast migration and invasion and impair trophoblast spheroid attachment to endometrial epithelial cells in vitro.