key: cord-0757016-9sd1ksgb authors: Mezouar, Soraya; Katsogiannou, Maria; Ben Amara, Amira; Bretelle, Florence; Mege, Jean-Louis title: Placental macrophages: Origin, heterogeneity, function and role in pregnancy-associated infections date: 2020-10-17 journal: Placenta DOI: 10.1016/j.placenta.2020.10.017 sha: 76736bf62cdec2ef0418b0b468819c97a4c2c6e9 doc_id: 757016 cord_uid: 9sd1ksgb Placental macrophages are a heterogenous population of immune cells present throughout pregnancy. They are essential for maintenance of the homeostatic placenta environment and host defense against infections. The characterization of placental macrophages as well as their activation have been limited for a long time by the lack of convenient tools. The emergence of unbiased methods makes it possible to reappraise the study of placental macrophages. In this review, we discuss the diversity and the functions of placental macrophages to better understand their dysfunctions during placental infections. heterogeneity of their origin. Initially, Hofbauer cells were thought to be in the chorionic villi, 121 suggesting a fetal origin, while deciduous macrophages were found in the decidua basalis in 122 contact with the maternal myometrium, suggesting a maternal origin (Graphical abstract). 123 The sex chromatin staining in the placenta of a newborn boy has shown that X and Y 124 chromosomes are found in macrophages from the fetal part, but only X chromosomes in 125 decidual macrophages [21] . We recently found that CD14 + macrophages isolated from at term 126 human placentas are of both maternal (30%) and fetal origin (70%) [19] . 127 The lack of convenient animal models for genetic fate mapping methods does not permit to Besides ontogenic heterogeneity, placental macrophages change their phenotype with 154 gestational age ( Table 1) . The phenotypic analysis of CD14 + macrophages reveal that seventy 155 percent of them express CD209 (dendritic cell-specific intercellular molecule adhesion 156 (ICAM)-3-grabbing non-integrin or DC-SIGN) and CD206 (mannose receptor), considered as 157 M2 markers (see below). The study of CD209 expression during first-trimester gestation has 158 shown the existence of two subsets of decidual macrophages. The major subset expresses 159 CD209 following CSF-1 stimulation [30] or combined action of CSF-1 and IL-10 [31]. These 160 CD209 + cells also express high levels of CD163, CD206, CD304 (neuropilin-1) and CD50 161 (ICAM-3), but low levels of CD11c, suggesting that they rather are M2 macrophages. [117] J o u r n a l P r e -p r o o f Streptococcus 599 agalactiae Induces Placental Macrophages To Release Extracellular Traps Loaded with Tissue 600 Remodeling Enzymes via an Oxidative Burst-Dependent Mechanism Isolation of human placental mast 603 cells A role for placental mast cells in normal and 605 complicated pregnancy Placental syncytiotrophoblast constitutes a major barrier to vertical transmission of Listeria 608 monocytogenes Placental Syncytium Forms a Biophysical Barrier against Pathogen Invasion Histopathologic findings in Brucella 614 abortus-infected, pregnant goats Pathologic and immunologic responses of the fetal lamb to 616 Leukemia inhibitory factor inhibits HIV-1 replication and is upregulated in placentae from nontransmitting women villous Hofbauer cells, and haematological precursors in eight-week fetuses Cellular localization of CD4 in the human placenta. Implications for maternal-626 to-fetal transmission of HIV Placental Hofbauer cells limit HIV-1 replication and 628 potentially offset mother to child transmission (MTCT) by induction of immunoregulatory 629 cytokines HIV 631 infection of placental macrophages: their potential role in vertical transmission Hofbauer cells assemble and sequester HIV-1 in tetraspanin-positive compartments that are 635 accessible to broadly neutralizing antibodies NK cells control HIV-1 infection of 639 macrophages through soluble factors and cellular contacts in the human decidua Viral infection, proliferation, and hyperplasia of Hofbauer cells and 642 absence of inflammation characterize the placental pathology of fetuses with congenital Zika 643 virus infection Zika Virus Infection during 646 Pregnancy and Congenital Abnormalities Zika virus infection 649 of Hofbauer cells Type III Interferons Produced by Human Placental 653 Trophoblasts Confer Protection against Zika Virus Infection Zika virus 659 damages the human placental barrier and presents marked fetal neurotropism, Mem Zika Virus Targets Different Primary Human Placental Cells, Suggesting 663 Two Routes for Vertical Transmission Cross-Reactive Dengue Virus 675 Antibodies Augment Zika Virus Infection of Human Placental Macrophages Zika Virus Infects Human Placental Macrophages Jak Inhibitors Modulate Production of Replication-Competent 683 Zika Virus in Human Hofbauer, Trophoblasts, and Neuroblastoma cells SARS-CoV-2 infection of the placenta Transplacental transmission of SARS-CoV-2 infection SARS-CoV2 vertical 697 transmission with adverse effects on the newborn revealed through integrated 698 immunohistochemical, electron microscopy and molecular analyses of Placenta SARS-CoV-2 placental infection and inflammation leading to fetal distress and neonatal 703 multi-organ failure in an asymptomatic woman, Infectious Diseases (except HIV/AIDS) Malaria elicits type 1 cytokines in the 706 human placenta: IFN-gamma and TNF-alpha associated with pregnancy outcomes Host Response to Malaria During 710 Pregnancy: Placental Monocyte Recruitment Is Associated with Elevated Chemokine 711 Expression How Hidden Can Malaria Be in Pregnant Women Polymerase Chain Reaction and Detection of 716 Protein 2 in Plasma Phagocytosis of Plasmodium-Infected Erythrocytes Malaria enhances expression of CC chemokine receptor 5 on 724 placental macrophages Elevations of amniotic fluid 726 macrophage inflammatory protein-1 alpha concentrations in women during term and preterm 727 labor Immunohistochemical characterization 729 of the inflammatory infiltrate in placental Chagas' disease: a qualitative and quantitative 730 analysis Role of placental barrier integrity in infection by Trypanosoma cruzi Placental Infection by Trypanosome 735 Cruzi, the Causal Agent of Congenital Chagas´ Disease Preterm Birth and Adverse Fetal-Neonatal Outcome Candida albicans infection of the amniotic sac A case of Candida guilliermondii abortion 744 in an Arab mare Recombinant cytokines in augmentation and 747 immunomodulation of host defenses against Candida spp The phenotype of human placental 749 macrophages and its variation with gestational age Two unique human 751 decidual macrophage populations HIV-1 Infection of First-Trimester and Term 754 Human Placental Tissue: A Possible Mode of Maternal-Fetal Transmission Toll-like receptor-mediated responses by placental Hofbauer 758 cells (HBCs): a potential pro-inflammatory role for fetal M2 macrophages Review article: Fc gamma receptors in the human placenta Decreased levels of folate receptor-β and reduced numbers of fetal 764 macrophages (Hofbauer cells) in placentas from pregnancies with severe pre-eclampsia, Am Characterisation of Hofbauer 767 cells in first and second trimester placenta: incidence, phenotype Hofbauer Cells: Their Role in Healthy and Complicated Human Placental Hofbauer Cells Maintain an Anti-773 inflammatory M2 Phenotype despite the Presence of Gestational Diabetes Mellitus Placental 776 macrophage (Hofbauer cell) polarization is independent of maternal allergen-sensitization and 777 presence of chorioamnionitis Placental Hofbauer cells and 780 complications of pregnancy The macrophage scavenger receptor 783 Placental expression of DC-SIGN may mediate intrauterine vertical transmission of 786 Up-regulation of CCR5 expression in the placenta is associated with human 789 immunodeficiency virus-1 vertical transmission Expression of the HIV-1 Co-receptors CCR5 Macrophages and the Effect of IL-10 on their Expression Regulation of 796 CCR5 Expression in Human Placenta: Insights from a Study of Mother-to-Child 797 Transmission of HIV in Malawi Macrophages of human first trimester decidua 801 express markers associated to alternative activation Macrophage populations in the human placenta and 804 amniochorion HLA-DR positive cells in the human placenta Cell type-specific expression 808 and function of toll-like receptors 2 and 4 in human placenta: implications in fetal infection Immunohistochemical distribution of Toll-like receptor 4 in term and preterm human 812 placentas from normal and complicated pregnancy including chorioamnionitis HIV: human immunodeficiency virus; HLA: human leukocyte antigen; ICAM: intercellular 836 adhesion molecule; LPS: lipopolysaccharide; Nr: not reported; ROI: reactive oxygen 837 intermediates; SDF-1: stromal-derived-factor-1