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Decidual macrophages and their roles at the maternal-fetal interface.

Houser BL - Yale J Biol Med (2012)

Bottom Line: The semi-allogeneic fetus, whose genome consists of maternally and paternally inherited alleles, must coexist with an active maternal immune system during its 9 months in utero.We have previously reported two distinct subsets of CD14(+) decidual macrophages found to be present in first trimester decidual tissue, 20 percent CD11c(HI) and 68 percent CD11c(LO).Thus, macrophage heterogeneity may be an important and necessary division of labor that leads to both an induction of maternal immune cell tolerance to fetal antigens as well as basic homeostatic functions in human pregnancy.

View Article: PubMed Central - PubMed

Affiliation: Stem Cell and Regenerative Biology Department, Harvard University, Boston, MA 02115, USA. bhouser@partners.org

ABSTRACT
The semi-allogeneic fetus, whose genome consists of maternally and paternally inherited alleles, must coexist with an active maternal immune system during its 9 months in utero. Macrophages are the second most abundant immune cell at the maternal-fetal interface, although populations and functions for these populations remain ill defined. We have previously reported two distinct subsets of CD14(+) decidual macrophages found to be present in first trimester decidual tissue, 20 percent CD11c(HI) and 68 percent CD11c(LO). Interestingly, CD11c(HI) decidual macrophages express genes associated with lipid metabolism, inflammation, and antigen presentation function and specifically upregulate CD1 molecules. Conversely, CD11c(LO) decidual macrophages express genes associated with extracellular matrix formation, muscle regulation, and tissue growth. The large abundance of CD11c(HI) decidual macrophages and their ability to process antigens more efficiently than CD11c(LO) macrophages suggests that CD11c(HI) macrophages may be important antigen processing and presenting cells at the maternal-fetal interface, while CD11c(LO) macrophages may perform necessary homeostatic functions during placental construction. Thus, macrophage heterogeneity may be an important and necessary division of labor that leads to both an induction of maternal immune cell tolerance to fetal antigens as well as basic homeostatic functions in human pregnancy.

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The Human Maternal-Fetal Interface. A block section of thechorioallantoic human placenta shows chorionic villous trees in direct contactwith the decidua basalis and the maternal blood supply in order to provideoxygen and nutrients to the growing fetus. The insert shows HLA-G+ extravillioustrophoblast cells invading the endothelium and unwinding the maternal spiralartery, allowing for maternal blood to enter the intervillous spaces. At thissite, fetal trophoblast cells come into direct contact with maternal immunecells such as dMφs, NK cells, and T cells.
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Figure 1: The Human Maternal-Fetal Interface. A block section of thechorioallantoic human placenta shows chorionic villous trees in direct contactwith the decidua basalis and the maternal blood supply in order to provideoxygen and nutrients to the growing fetus. The insert shows HLA-G+ extravillioustrophoblast cells invading the endothelium and unwinding the maternal spiralartery, allowing for maternal blood to enter the intervillous spaces. At thissite, fetal trophoblast cells come into direct contact with maternal immunecells such as dMφs, NK cells, and T cells.

Mentions: Placentation begins when fetal-derived trophoblast cells from the recently implantedblastocyst invade the uterine lining. Simultaneously, cells of the endometrium alsobegin to prepare for this invasion, in a process known as decidualization[3]. The mammalianchorioallantoic placenta is essential for the growth and development of the fetusand distinguishes Eutherian mammals from other organisms. There are three main typesof Eutherian placentation: epitheliochorial, endotheliochorial, and hemochorial[4]. These distinctionsare made based upon contact between trophoblast cells and the uterine lining. Inepitheliochorial placentation, trophoblast cells can reach and sometimes fuse withthe surface epithelium of the uterus, while in endotheliochorial placentation,trophoblasts can reach the maternal blood vessels [5]. Humans undergo hemochorial placentation, whereinfetal membranes are in direct contact with maternal tissue and blood (Figure 1). This intimate contact between thefetal-placental unit and mother was established in the last common crown group ofEutheria and gives credence that a successful pregnancy requires appropriateallorecognition and tolerance at the maternal-fetal interface [6].


Decidual macrophages and their roles at the maternal-fetal interface.

Houser BL - Yale J Biol Med (2012)

The Human Maternal-Fetal Interface. A block section of thechorioallantoic human placenta shows chorionic villous trees in direct contactwith the decidua basalis and the maternal blood supply in order to provideoxygen and nutrients to the growing fetus. The insert shows HLA-G+ extravillioustrophoblast cells invading the endothelium and unwinding the maternal spiralartery, allowing for maternal blood to enter the intervillous spaces. At thissite, fetal trophoblast cells come into direct contact with maternal immunecells such as dMφs, NK cells, and T cells.
© Copyright Policy - open access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3313525&req=5

Figure 1: The Human Maternal-Fetal Interface. A block section of thechorioallantoic human placenta shows chorionic villous trees in direct contactwith the decidua basalis and the maternal blood supply in order to provideoxygen and nutrients to the growing fetus. The insert shows HLA-G+ extravillioustrophoblast cells invading the endothelium and unwinding the maternal spiralartery, allowing for maternal blood to enter the intervillous spaces. At thissite, fetal trophoblast cells come into direct contact with maternal immunecells such as dMφs, NK cells, and T cells.
Mentions: Placentation begins when fetal-derived trophoblast cells from the recently implantedblastocyst invade the uterine lining. Simultaneously, cells of the endometrium alsobegin to prepare for this invasion, in a process known as decidualization[3]. The mammalianchorioallantoic placenta is essential for the growth and development of the fetusand distinguishes Eutherian mammals from other organisms. There are three main typesof Eutherian placentation: epitheliochorial, endotheliochorial, and hemochorial[4]. These distinctionsare made based upon contact between trophoblast cells and the uterine lining. Inepitheliochorial placentation, trophoblast cells can reach and sometimes fuse withthe surface epithelium of the uterus, while in endotheliochorial placentation,trophoblasts can reach the maternal blood vessels [5]. Humans undergo hemochorial placentation, whereinfetal membranes are in direct contact with maternal tissue and blood (Figure 1). This intimate contact between thefetal-placental unit and mother was established in the last common crown group ofEutheria and gives credence that a successful pregnancy requires appropriateallorecognition and tolerance at the maternal-fetal interface [6].

Bottom Line: The semi-allogeneic fetus, whose genome consists of maternally and paternally inherited alleles, must coexist with an active maternal immune system during its 9 months in utero.We have previously reported two distinct subsets of CD14(+) decidual macrophages found to be present in first trimester decidual tissue, 20 percent CD11c(HI) and 68 percent CD11c(LO).Thus, macrophage heterogeneity may be an important and necessary division of labor that leads to both an induction of maternal immune cell tolerance to fetal antigens as well as basic homeostatic functions in human pregnancy.

View Article: PubMed Central - PubMed

Affiliation: Stem Cell and Regenerative Biology Department, Harvard University, Boston, MA 02115, USA. bhouser@partners.org

ABSTRACT
The semi-allogeneic fetus, whose genome consists of maternally and paternally inherited alleles, must coexist with an active maternal immune system during its 9 months in utero. Macrophages are the second most abundant immune cell at the maternal-fetal interface, although populations and functions for these populations remain ill defined. We have previously reported two distinct subsets of CD14(+) decidual macrophages found to be present in first trimester decidual tissue, 20 percent CD11c(HI) and 68 percent CD11c(LO). Interestingly, CD11c(HI) decidual macrophages express genes associated with lipid metabolism, inflammation, and antigen presentation function and specifically upregulate CD1 molecules. Conversely, CD11c(LO) decidual macrophages express genes associated with extracellular matrix formation, muscle regulation, and tissue growth. The large abundance of CD11c(HI) decidual macrophages and their ability to process antigens more efficiently than CD11c(LO) macrophages suggests that CD11c(HI) macrophages may be important antigen processing and presenting cells at the maternal-fetal interface, while CD11c(LO) macrophages may perform necessary homeostatic functions during placental construction. Thus, macrophage heterogeneity may be an important and necessary division of labor that leads to both an induction of maternal immune cell tolerance to fetal antigens as well as basic homeostatic functions in human pregnancy.

Show MeSH