Embryo Quality Conditions the Secretory Profile of Tolerogenic Dendritic Cell DC-10 During the Peri-Implantation Period

Problem: The decidualization process conditions monocytes to the immunosuppressive and tolerogenic dendritic cell (DC)-10 profile, a DC subset with high IL-10 production. Since the implantation process implies an embryo-endometrium-immune crosstalk, here we focused on the ability of embryonic soluble factors to modify decidual DC conditioning accordingly with its quality. Method of Study: Human endometrial stromal cell line (HESC) decidualized with medroxyprogesterone and dibutyryl-cAMP (Dec) was stimulated with human embryo-conditioned media (ECM), classified as normal (ND) or impaired developed (ID) for 48 h (n = 18/group). Monocytes isolated from six healthy women were differentiated to DCs with rhGM-CSF+rhIL-4 in the presence/absence of conditioned media (CM) from decidualized cells stimulated with ECM or nontreated. Results: We found that decidualized cells stimulated with ECM sustain a myeloid regulatory cell profile on monocyte-derived culture with increased frequency of CD1a(-)CD14(+) and CD83(+)CD86(low) cells. ND-Dec sustained the higher expression of the DC-10 markers, HLA-G and IL-10 whereas ID-Dec diminished IL-10 production (ID-Dec: 135 +/- 37.4 vs. Dec: 223.3 +/- 49.9 pg/mL, p < 0.05). The treatment with ECM-Dec sustained a higher IL-10 production and prevented the increase of CD83/CD86 after LPS challenge regardless of embryo quality. Notably, TNF-alpha production increased in ID-Dec cultures (ID-Dec: 475.1 +/- 134.7 vs. Dec: 347.5 +/- 98 pg/mL, p < 0.05). Conclusions: Although remaining in a tolerogenic profile compatible with DC-10, DCs can differentially respond to decidual secreted factors based on embryo quality, changing their secretome. These results suggest that in the presence of arrested embryo, DCs could differentially shape the immunological microenvironment, contributing to arrested embryo clearance during the menstrual phase.