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Salmonella enterica species are intracellular bacteria causative agents of gastroenteritis and typhoid fever in humans. Pregnancy poses an increased risk of severe Salmonellosis in many mammalian species contributing to miscarriage and/or maternal illness. Previous studies indicated that Salmonella infection in pregnant mice caused rapid fetal and maternal death due to massive bacterial proliferation in the placenta. However, the susceptibility of human primary trophoblast cells (cTBCs) to Salmonella infection was not known. We hypothesized that human placental trophoblast cells are productively infected and provide a unique intracellular niche that permits uncontrolled Salmonella replication due to an ineffective maternal innate immune response to the virulent bacteria resulting in placental death. Firstly, we observed that S.Tm strains defective in the Salmonella pathogenicity island (SPI)-1 type III secretion system (TTSS) (S.Tm-ΔinvA) were unable to enter epithelial cells, but efficiently infected placental choriocarcinoma cell lines through scavenger receptor-mediated endocytosis. Next, we observed that S.Tm failed to grow vigorously in macrophages, but replicated rapidly within epithelial and placental trophoblast cells. Further examination of intracellular localization of S.Tm indicated that bacteria were arrested in early Rab5 expressing phagosomal vesicles within trophoblast cells, whereas phagosomal maturation progressed steadily in macrophages (with expression of lysosomal-associated membrane protein-1 (LAMP-1) and cathepsin D). Moreover, human primary cTBCs harboring S.Tm underwent rapid death of the cells. Infected cTBCs expressed phosphorylated-receptor-interacting serine/threonine-protein kinase (RIPK)-1 protein and phosphorylated-mixed lineage kinase domain-like (MLKL), suggesting induction of the necroptosis pathway of cell death. Furthermore, specific inhibition of necroptosis rescued S.Tm-induced death of cTBCs. Finally, S.Tm infected trophoblast cells produced interleukin (IL)-10, and signal transducer and activator of transcription (STAT)-3 signalling. This correlated to delayed phagosomal maturation which consequently facilitated intracellular pathogen proliferation. Overall, human trophoblast cells may act as reservoirs for S.Tm survival and may aid dissemination in the pregnant host.

O biglicam é um proteoglicano é altamente expresso em células trofoblásticas de patologias placentárias com invasividade exacerbada. No entanto, as funções do biglicam no trofoblasto ainda não foram elucidadas. Sendo assim, verificamos a expressão e as funções de biglicam e seus receptores Toll-like (TLR)-2 e TLR-4 nas células trofoblásticas durante a gestação. As células do citotrofoblasto extraviloso (CTEV) foram positivas para todas as moléculas, menos para o biglicam em placentas a termo. Adição exógena de biglicam promoveu migração e invasão das células trofoblásticas. O biglicam estimulou a fosforilação de AKT nos sítios Thr308 e Ser473 nas células trofoblásticas. A migração e a invasão biglicam-dependentes e as fosforilações de AKT foram inibidas após a adição de anticorpos bloqueadores anti-TLR-2 e anti-TLR-4. O silenciamento gênico de AKT1 em células SGHPL-5 aboliu os efeitos do biglicam na motilidade. Em conclusão, o biglicam aumenta a motilidade de células trofoblásticas após sinalização por AKT através da ativação de TLR-2 e TLR-4. / Biglycan is a highly expressed proteoglycan in trophoblast cells from invasiveness-changed placental pathologies. However, biglycan functions in the trophoblast were not yet identified. Therefore, it was verified the expression and functions of biglycan and its receptors Toll-like (TLR)-2 and TLR-4 in trophoblast cells throughout pregnancy. The extravillous cytotrophoblast cells (EVT) were positive to all the molecules, although biglycan was negative in term placentas. Exogenous biglycan promoted migration and invasion of trophoblast cells. Biglycan stimulated AKT phosphorilation at Thr308 and Ser473 sites in trophoblast cells. The biglycan-dependent migration, invasion and AKT phosphorilation were inhibited upon addiction of anti-TLR-2 and anti-TLR-4 blocking antibodies. AKT1 genic silencing in SGHPL-5 cells abolished the motility effects. In conclusion, biglycan increases the motility of trophoblast cells after AKT signaliing throughout TLR-2 and TLR-4 activation.

O biglicam é um proteoglicano é altamente expresso em células trofoblásticas de patologias placentárias com invasividade exacerbada. No entanto, as funções do biglicam no trofoblasto ainda não foram elucidadas. Sendo assim, verificamos a expressão e as funções de biglicam e seus receptores Toll-like (TLR)-2 e TLR-4 nas células trofoblásticas durante a gestação. As células do citotrofoblasto extraviloso (CTEV) foram positivas para todas as moléculas, menos para o biglicam em placentas a termo. Adição exógena de biglicam promoveu migração e invasão das células trofoblásticas. O biglicam estimulou a fosforilação de AKT nos sítios Thr308 e Ser473 nas células trofoblásticas. A migração e a invasão biglicam-dependentes e as fosforilações de AKT foram inibidas após a adição de anticorpos bloqueadores anti-TLR-2 e anti-TLR-4. O silenciamento gênico de AKT1 em células SGHPL-5 aboliu os efeitos do biglicam na motilidade. Em conclusão, o biglicam aumenta a motilidade de células trofoblásticas após sinalização por AKT através da ativação de TLR-2 e TLR-4. / Biglycan is a highly expressed proteoglycan in trophoblast cells from invasiveness-changed placental pathologies. However, biglycan functions in the trophoblast were not yet identified. Therefore, it was verified the expression and functions of biglycan and its receptors Toll-like (TLR)-2 and TLR-4 in trophoblast cells throughout pregnancy. The extravillous cytotrophoblast cells (EVT) were positive to all the molecules, although biglycan was negative in term placentas. Exogenous biglycan promoted migration and invasion of trophoblast cells. Biglycan stimulated AKT phosphorilation at Thr308 and Ser473 sites in trophoblast cells. The biglycan-dependent migration, invasion and AKT phosphorilation were inhibited upon addiction of anti-TLR-2 and anti-TLR-4 blocking antibodies. AKT1 genic silencing in SGHPL-5 cells abolished the motility effects. In conclusion, biglycan increases the motility of trophoblast cells after AKT signaliing throughout TLR-2 and TLR-4 activation.

My dissertation hypothesis is that bovine trophoblast cells express cell-surface and secreted non-classical major histocompatibility complex class I (MHC-Ib) proteins which inhibit NK cells and other leukocytes by binding to inhibitory receptors (e.g., LILRB1, LILRB2, KIR2DL4, and/or CD94/NKG2A). Extremely polymorphic and ubiquitously expressed classical MHC class I (MHC-Ia) proteins, which present foreign antigenic peptides to CD8+ T lymphocytes, are involved in acceptance or rejection of tissue grafts. Non-classical MHC class I (MHC-Ib) glycoproteins, such as Human Leukocyte Antigen-G (HLA-G) and murine Qa-2, are important modulators of the maternal immune system during pregnancy. MHC-Ib proteins are: (a) oligomorphic or monomorphic, (b) expressed in specific tissues under specific condtions, and (c) produced as surface and/or soluble isoforms due to alternative splicing. Third trimester-bovine trophoblast cells express both MHC-Ia and MHC-Ib proteins. The MHC-Ib proteins expressed by trophoblast cells during the third trimester of pregnancy are encoded by four bovine leukocyte antigen (BoLA) loci: BoLA-NC1, BoLA-NC2, BoLA-NC3, and BoLA-NC4. Two MHC-Ia (N*01701 and N*01802) and three MHC-Ib (NC1*00501, NC3*00101 and NC4*00201) proteins showed cell-surface expression in transfection studies performed in murine P815 and human K562 cells. Two additional isoforms, NC1*00401 and NC2*00102, were not detected on the surface of these cells. Nevertheless, both class Ia proteins, N*01701 and N*01802, and five class Ib proteins, NC1*00401, NC1*00501, NC2*00102, NC3*00101, and NC4*00201, were detected in crude cell lysates on Western blots. Precipitation of proteins from culture supernatants showed that cell-surface MHC-Ia (N*01701 and N*01802) and MHC-Ib proteins (NC1*00501, NC3*00101, and NC4*00201) are shed from the surface of these cells into the media. The mechanism of shedding of these proteins is, however, not known. Monoclonal antibodies W6/32, IL-A88, H1A, H6A, H11A, H58A, and PT-85A recognized surface MHC-I isoforms with varying affinity. We were able to develop a sandwich enzyme-linked immunosorbent assay (ELISA) using either H1A or IL-A88 antibody as the capture antibody and the W6/32 antibody for detection. We produced monoclonal antibodies against cattle NC1*00501 and NC3*00101 proteins. One monoclonal antibody generated against BoLA-NC3*00101 was highly specific. Unfortunately, due to failure to clone the NC3*00101- hybridoma, we no longer have an infinite source of this monoclonal antibody for NC3*00101. We eluted peptides from NC3*00101-transfected MHC-null K562 cells and identified peptides using liquid chromatography-mass spectrum (LC-MS) analysis. Analysis of peptide binding data using the SAS Proc mixed statistical program, suggested that the peptide EVTNQLVVL is a potential peptide ligand, which can be used to make tetramers for enumeration of antigen-specific leukocytes.

Spiral-artery (SA) remodeling is a fundamental process during pregnancy that involves the action of cells of the initial vessel, such as vascular smooth-muscle cells (VSMCs) and endothelial cells, but also maternal immune cells and fetal extravillous trophoblast cells (EVTs). Mast cells (MCs), and specifically chymase-expressing cells, have been identified as key to a sufficient SA remodeling process in vivo. However, the mechanisms are still unclear. The purpose of this study is to evaluate the effects of the MC line HMC-1 and recombinant human chymase (rhuCMA1) on human primary uterine vascular smooth-muscle cells (HUtSMCs), a human trophoblast cell line (HTR8/SV-neo), and human umbilical-vein endothelial cells (HUVEC) in vitro. Both HMC-1 and rhuCMA1 stimulated migration, proliferation, and changed protein expression in HUtSMCs. HMC-1 increased proliferation, migration, and changed gene expression of HTR8/SVneo cells, while rhuCMA treatment led to increased migration and decreased expression of tissue inhibitors of matrix metalloproteinases. Additionally, rhuCMA1 enhanced endothelial-cell-tube formation. Collectively, we identified possible mechanisms by which MCs/rhuCMA1 promote SA remodeling. Our findings are relevant to the understanding of this crucial step in pregnancy and thus of the dysregulated pathways that can lead to pregnancy complications such as fetal growth restriction and preeclampsia.