Trojan Horses and Achilles' Heel; Listeria monocytogenes use blood monocytes to travel to the decidua and infect the placenta
Résumé
Listeria monocytogenes are Gram-positive facultative intracellular bacteria and are a well-known threat for women and fetuses during pregnancy. Recent findings suggest that the primary vulnerability of the placenta is in the implantation site, specifically at the level of extravillous cytotrophoblasts (EVTs). However, EVTs are not accessible to the bacteria from the blood where they are found. Here, we used human primary blood cells and human placental explants to explore the possible pathways used by L. monocytogenes to travel from blood to placenta and then to spread to the fetus. We first showed that blood monocytes are specifically susceptible to listerial infection and are a good candidate as carrier of the bacteria through the bloodstream. After blood monocyte infection, L. monocytogenes would have to colonize the Decidua in order to access the placenta. We then characterized the infection of decidual cells and observed that decidual fibroblasts, macrophages and NK cells are very sensitive to infection. Decidual Nk cells actually undergo a rapid induction of apoptosis following the infection with L. monocytogenes. Finally, we showed that these infected leukocytes can interact with the human placenta, and that EVTs are much more susceptible to infection than the syncytium. L. monocytogenes can then travel form infected leukocytes to EVTs and thus infect the placenta, and later the fetus.
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Mikaty 2016.pdf (278.63 Ko)
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Origine : Fichiers produits par l'(les) auteur(s)
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