The human placenta shapes the phenotype of decidual macrophages

Abstract

During human pregnancy, placenta-derived extravillous trophoblasts (EVT) invade the decidua and communicate with maternal immune cells. The decidua can be distinguished into basalis (decB) and parietalis (decP), the latter being unaffected by placentation. By defining a novel gating strategy, we report accumulation of myeloid cells in decB. We identified a decidua basalis-associated macrophage (decBAM) population with a differential transcriptome and secretome when compared to decidua parietalis-associated macrophages (decPAMs). decBAMs are CD11chi and efficient inducers of Tregs, proliferate in situ and secrete high levels of CXCL1, CXCL5, M-CSF, and IL-10. In contrast, decPAMs exert a dendritic cell-like, motile phenotype characterized by induced expression of HLA class II molecules, enhanced phagocytosis, and the ability to activate T cells. Strikingly, EVT-conditioned media are able to convert decPAMs into a decBAM phenotype. Cumulatively, these findings assign distinct macrophage phenotypes to decidual areas depending on placentation and further highlight a critical role for EVTs in the induction of pregnancy-tolerant macrophage polarization.

Isolation of Decidual Macrophages and Hofbauer Cells from Term Placenta—Comparison of the Expression of CD163 and CD80

“…Comparing both populations, we could not find a significant difference of CD163 + . There were no comparable results in the literature, however CD163 is expressed either in Hofbauer cells and decidual macrophages, nevertheless CD163 is better known for typical M2-like polarized Hofbauer cells [ 72 , 73 ].…”

Myeloperoxidase enhances the migration of human choriocarcinoma JEG-3 cells1

“…In the placenta, the presence of neutrophils and MPO in the DB has been confirmed (4,5,15). Furthermore, higher MPO levels on the surface of blood neutrophils have been observed during pregnancy (16); however, its abundance and role during first trimester implantation and placentation remains unclear.…”

“…Maternal leukocytes, particularly uterine natural killer cells, regulate EVT invasion and are important for normal development during pregnancy (3). However, other maternal immune cells, such as neutrophils, are also required for the development of a healthy feto-maternal interface, including neutrophils, which are highly present in the decidua basalis (DB) (4). Neutrophils are part of the innate immune system and are one of the first cell types that respond to acute inflammation.…”