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Pregnancy outcome relies on the maintenance of immune and metabolic homeostasis at the maternal fetal interface. Maternal and perinatal morbidity and mortality is associated with impaired placental development. Multiple regulatory effects of the endogenous-produced vasoactive intestinal peptide (VIP) on vascular, metabolic and immune functions at the maternal-fetal interface have been reported. Here we studied the involvement of the two primary high affinity receptors for VIP (VPAC1 and VPAC2) on maternal immune response, placental homeostasis and pregnancy outcome. Targeted disruption of each receptor gene led to altered placental structure, vascular and trophoblast functional markers and shaped the functional profiles of macrophages and neutrophils towards a proinflammatory state. Several changes in pregnant mice were receptor specific: ROS production elicited by VIP on neutrophils was selectively dependent on the presence of VPAC1 whereas apoptosis rate was associated with the VPAC2 deletion. In peritoneal macrophages from pregnant mice, levels of MHC-II, TLR2, and IL-10 were selectively altered in VPAC2 receptor-deficient mice, whereas IL-6 gene expression was reduced only in mice lacking VPAC1 receptors. Additionally, MMP9 mRNA in isolated TGCs was reduced in VPAC2 receptor deleted mice, while the percentage of IL-12 cells in post-phagocytosis macrophage cultures was selectively reduced in VPAC2 receptor deficient mice. The results indicate that manipulation of VPAC1 and VPAC2 receptor affects immune, vascular and metabolic environment at the maternal fetal interface. These mouse models offer new approaches to study pregnancy complications adding new perspectives to the development of VPAC receptor-selective drugs.

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+CD86low 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‐α 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. [ABSTRACT FROM AUTHOR]

Immunometabolism research is uncovering the relationship between metabolic features and immune cell functions in physiological and pathological conditions. Normal pregnancy entails a fine immune and metabolic regulation of the maternal-fetal interaction to assist the energetic demands of the fetus with immune homeostasis maintenance. Here, we determined the immunometabolic status of monocytes of pregnant women compared with nonpregnant controls and its impact on monocyte anti-inflammatory functions such as efferocytosis. Monocytes from pregnant women (16-20 wk) and nonpregnant age-matched controls were studied. Single cell-based metabolic assays using freshly isolated monocytes from both groups were carried out in parallel with functional assays ex vivo to evaluate monocyte efferocytic capacity. On the other hand, various in vitro metabolic assays with human monocytes or monocyte-derived macrophages were designed to explore the effect of trophoblast cells in the profiles observed. We found that pregnancy alters monocyte metabolism and function. An increased glucose dependency and enhanced efferocytosis were detected in monocytes from pregnant women at resting states, compared with nonpregnant controls. Furthermore, monocytes display a reduced glycolytic response when stimulated with lipopolysaccharide (LPS). The metabolic profiling of monocytes at this stage of pregnancy was comparable with the immunometabolic phenotypes of human monocytes treated in vitro with human first trimester trophoblast cell conditioned media. These findings suggest that immunometabolic mechanisms are involved in the functional shaping of monocytes during pregnancy with a contribution of trophoblast cells. Results provide new clues for future hypotheses regarding pregnancies complicated by metabolic disorders. [ABSTRACT FROM AUTHOR]

Problem: Decidualized cells display an active role during embryo implantation sensing blastocyst quality, allowing the implantation of normal developed blastocysts and preventing the invasion of impaired developed ones. Here, we characterized the immune microenvironment generated by decidualized cells in response to soluble factors secreted by blastocysts that shape the receptive milieu. Method of Study: We used an in vitro model of decidualization based on the Human Endometrial Stromal Cells line (HESC) differentiated with medroxiprogesterone and dibutyryl‐cAMP, then treated with human blastocysts‐conditioned media (BCM) classified according to their quality. Results: Decidualized cells treated with BCM from impaired developed blastocysts increased IL‐1β production. Next, we evaluated the ability of decidualized cells to modulate other mediators associated with menstruation as chemokines. Decidualized cells responded to stimulation with BCM from impaired developed blastocysts increasing CXCL12 expression and CXCL8 secretion. The modulation of these markers was associated with the recruitment and activation of neutrophils, while regulatory T cells recruitment was restrained. These changes were not observed in the presence of BCM from normal developed blastocysts. Conclusion: Soluble factors released by impaired developed blastocysts induce an exacerbated inflammatory response associated with neutrophils recruitment and activation, providing new clues to understand the molecular basis of the embryo‐endometrial dialogue. [ABSTRACT FROM AUTHOR]