324 research outputs found
In vivo analysis of staphylococcus aureus-infected mice reveals differential temporal and spatial expression patterns of fhuD2
Staphylococcus aureus is an opportunistic human pathogen and a major cause of invasive infections such as bacteremia, endocarditis, pneumonia and wound infections. FhuD2 is a staphylococcal lipoprotein involved in the uptake of iron-hydroxymate and is under the control of the iron uptake regulator Fur. The protein is part of an investigational multi-component vaccine formulation that has shown protective efficacy in several murine models of infection. Even though fhuD2 expression was shown to be upregulated in murine kidneys infected with S. aureus, it is unknown whether the bacterium undergoes increased iron deprivation during prolonged infection. Furthermore, different infection niches of S. aureus might provide different environments and iron availability resulting in different fhuD2 expression pattern within different host organs. To address these questions, we characterized the in vitro expression of the fhuD2 gene and confirmed Fur-dependent iron-regulation of its expression. We further investigated its expression in mice infected with a bioluminescent reporter strain of S. aureus expressing the luciferase operon under the control of the fhuD2 promoter. The emission of bioluminescence in different organs was followed over a seven-day time course, as well as quantitative real-time PCR analysis of the RNA transcribed from the endogenous fhuD2 gene. Using this approach, we could show that fhuD2 expression was induced during infection in all organs analyzed and that differences in expression were observed in the temporal expression profiles, and between infected organs. Our data suggest that S. aureus undergoes increased iron deprivation during progression of infection in diverse host organs and accordingly induces dedicated iron acquisition mechanisms. Since FhuD2 plays a central role in providing the pathogen with the required iron, further knowledge of the patterns of fhuD2 expression in vivo during infection is instrumental in better defining the role of this antigen in S. aureus pathogenesis and as a vaccine antigen
Influence of relative NK-DC abundance on placentation and its relation to epigenetic programming in the offspring
Normal placentation relies on an efficient maternal adaptation to pregnancy. Within the decidua, natural killer (NK) cells and dendritic cells (DC) have a critical role in modulating angiogenesis and decidualization associated with pregnancy. However, the contribution of these immune cells to the placentation process and subsequently fetal development remains largely elusive. Using two different mouse models, we here show that optimal placentation and fetal development is sensitive to disturbances in NK cell relative abundance at the fetal–maternal interface. Depletion of NK cells during early gestation compromises the placentation process by causing alteration in placental function and structure. Embryos derived from NK-depleted dams suffer from intrauterine growth restriction (IUGR), a phenomenon that continued to be evident in the offspring on post-natal day 4. Further, we demonstrate that IUGR was accompanied by an overall reduction of global DNA methylation levels and epigenetic changes in the methylation of specific hepatic gene promoters. Thus, temporary changes within the NK cell pool during early gestation influence placental development and function, subsequently affecting hepatic gene methylation and fetal metabolism.Fil: Freitag, Nancy. Medicine University of Berlin; AlemaniaFil: Zwier, M. V.. University of Groningen; PaÃses BajosFil: Barrientos, Gabriela Laura. Medicine University of Berlin; Alemania. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Tirado González, Irene. Medicine University of Berlin; AlemaniaFil: Conrad, Melanie L.. Medicine University of Berlin; AlemaniaFil: Rose, Matthias. Medicine University of Berlin; AlemaniaFil: Scherjon, S. A.. University of Groningen; PaÃses BajosFil: Plösch, T.. University of Groningen; PaÃses BajosFil: Blois, Sandra M.. Medicine University of Berlin; Alemani
Altered Glycosylation Contributes to Placental Dysfunction Upon Early Disruption of the NK Cell-DC Dynamics
Immune cells [e. g., dendritic cells (DC) and natural killer (NK) cells] are critical players during the pre-placentation stage for successful mammalian pregnancy. Proper placental and fetal development relies on balanced DC-NK cell interactions regulating immune cell homing, maternal vascular expansion, and trophoblast functions. Previously, we showed thatin vivodisruption of the uterine NK cell-DC balance interferes with the decidualization process, with subsequent impact on placental and fetal development leading to fetal growth restriction. Glycans are essential determinants of reproductive health and the glycocode expressed in a particular compartment (e.g., placenta) is highly dependent on the cell type and its developmental and pathological state. Here, we aimed to investigate the maternal and placental glycovariation during the pre- and post-placentation period associated with disruption of the NK cell-DC dynamics during early pregnancy. We observed that depletion of NK cells was associated with significant increases of O- and N-linked glycosylation and sialylation in the decidual vascular zone during the pre-placental period, followed by downregulation of core 1 and poly-LacNAc extended O-glycans and increased expression of branched N-glycans affecting mainly the placental giant cells and spongiotrophoblasts of the junctional zone. On the other hand, expansion of DC induced a milder increase of Tn antigen (truncated form of mucin-type O-glycans) and branched N-glycan expression in the vascular zone, with only modest changes in the glycosylation pattern during the post-placentation period. In both groups, this spatiotemporal variation in the glycosylation pattern of the implantation site was accompanied by corresponding changes in galectin-1 expression. Our results show that pre- and post- placentation implantation sites have a differential glycopattern upon disruption of the NK cell-DC dynamics, suggesting that immune imbalance early in gestation impacts placentation and fetal development by directly influencing the placental glycocode
Uterine NK cells are critical in shaping DC immunogenic functions compatible with pregnancy progression.
Dendritic cell (DC) and natural killer (NK) cell interactions are important for the regulation of innate and adaptive immunity, but their relevance during early pregnancy remains elusive. Using two different strategies to manipulate the frequency of NK cells and DC during gestation, we investigated their relative impact on the decidualization process and on angiogenic responses that characterize murine implantation. Manipulation of the frequency of NK cells, DC or both lead to a defective decidual response characterized by decreased proliferation and differentiation of stromal cells. Whereas no detrimental effects were evident upon expansion of DC, NK cell ablation in such expanded DC mice severely compromised decidual development and led to early pregnancy loss. Pregnancy failure in these mice was associated with an unbalanced production of anti-angiogenic signals and most notably, with increased expression of genes related to inflammation and immunogenic activation of DC. Thus, NK cells appear to play an important role counteracting potential anomalies raised by DC expansion and overactivity in the decidua, becoming critical for normal pregnancy progression
Differential Spatiotemporal Patterns of Galectin Expression are a Hallmark of Endotheliochorial Placentation
Problem: Galectins influence the progress of pregnancy by regulating key processes associated with embryo-maternal cross talk, including angiogenesis and placentation. Galectin family members exert multiple roles in the context of hemochorial and epitheliochorial placentation; however, the galectin prolife in endotheliochorial placenta remains to be investigated. Method of study: Here, we used immunohistochemistry to analyze galectin (gal)-1, gal-3 and gal-9 expression during early and late endotheliochorial placentation in two different species (dogs and cats). Results: We found that during early feline gestation, all three galectin members were more strongly expressed on trophoblast and maternal vessels compared to the decidua. This was accompanied by an overall decrease of gal-1, gal-3 and gal-9 expressions in late feline gestation. In canine early pregnancy, we observed that gal-1 and gal-9 were expressed strongly in cytotrophoblast (CTB) cells compared to gal-3, and no galectin expression was observed in syncytiotrophoblast (STB) cells. Progression of canine gestation was accompanied by increased gal-1 and gal-3 expressions on STB cells, whereas gal-9 expression remained similar in CTB and STB. Conclusion: These data suggest that both the maternal and fetal compartments are characterized by a spatiotemporal regulation of galectin expression during endotheliochorial placentation. This strongly suggests the involvement of the galectin family in important developmental processes during gestation including immunemodulation, trophoblast invasion and angiogenesis. A conserved functional role for galectins during mammalian placental development emerges from these studies.Facultad de Ciencias Veterinaria
Differential Spatiotemporal Patterns of Galectin Expression are a Hallmark of Endotheliochorial Placentation
Problem: Galectins influence the progress of pregnancy by regulating key processes associated with embryo-maternal cross talk, including angiogenesis and placentation. Galectin family members exert multiple roles in the context of hemochorial and epitheliochorial placentation; however, the galectin prolife in endotheliochorial placenta remains to be investigated. Method of study: Here, we used immunohistochemistry to analyze galectin (gal)-1, gal-3 and gal-9 expression during early and late endotheliochorial placentation in two different species (dogs and cats). Results: We found that during early feline gestation, all three galectin members were more strongly expressed on trophoblast and maternal vessels compared to the decidua. This was accompanied by an overall decrease of gal-1, gal-3 and gal-9 expressions in late feline gestation. In canine early pregnancy, we observed that gal-1 and gal-9 were expressed strongly in cytotrophoblast (CTB) cells compared to gal-3, and no galectin expression was observed in syncytiotrophoblast (STB) cells. Progression of canine gestation was accompanied by increased gal-1 and gal-3 expressions on STB cells, whereas gal-9 expression remained similar in CTB and STB. Conclusion: These data suggest that both the maternal and fetal compartments are characterized by a spatiotemporal regulation of galectin expression during endotheliochorial placentation. This strongly suggests the involvement of the galectin family in important developmental processes during gestation including immunemodulation, trophoblast invasion and angiogenesis. A conserved functional role for galectins during mammalian placental development emerges from these studies.Facultad de Ciencias Veterinaria
PrfA activation in Listeria monocytogenes increases the sensitivity to class IIa bacteriocins despite impaired expression of the bacteriocin receptor
Background: The scope of the present work was to characterize the activity of class IIa bacteriocins in Listeria (L.) monocytogenes cells that constitutively express an activated form of PrfA, the virulence master regulator, since bacteriocin sensitivity was only characterized in saprophytic cells so far. The mannose phosphotransferase system (Man-PTS) has been shown to be the class IIa bacteriocin receptor in Listeria; hence, special attention was paid to its expression in virulent bacteria.
Methods: L. monocytogenes FBprfA* cells were obtained by transconjugation. Bacterial growth was studied in TSB and glucose containing-minimal medium. Sensitivity to antimicrobial peptides was assessed by killing curves. Membranes of L. monocytogenes FBprfA* cells were characterized using proteomic and lipidomic approaches.
Results: The mannose phosphotransferase system (Man-PTS) was downregulated upon expression of PrfA*, and these cells turned out to be more sensitive to enterocin CRL35 and pediocin PA-1, while not to nisin. Proteomic and lipidomic analysis showed differences between wild type (WT) and PrfA* strains. For instance, phosphatidic acid was only detected in PrfA* cells, whereas, there was a significant decline of plasmalogen-phosphatidylglycerol in the same strain.
Conclusions: Our results support a model in which Man-PTS acts just as a docking molecule that brings class IIa bacteriocins to the plasma membrane. Furthermore, our results suggest that lipids play a crucial role in the mechanism of action of bacteriocins.Fil: Farizano, Juan Vicente. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de BioquÃmica, QuÃmica y Farmacia. Instituto de QuÃmica Biológica; ArgentinaFil: Masias, Ruth Emilse. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina. Universidad Nacional de Tucumán. Facultad de BioquÃmica, QuÃmica y Farmacia. Instituto de QuÃmica Biológica; ArgentinaFil: Hsu, Fong Fu. University of Washington; Estados UnidosFil: Salomon, Raul Armando. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina. Universidad Nacional de Tucumán. Facultad de BioquÃmica, QuÃmica y Farmacia. Instituto de QuÃmica Biológica; ArgentinaFil: Freitag, Nancy. University of Illinois; Estados UnidosFil: Hebert, Elvira Maria. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Minahk, Carlos Javier. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina. Universidad Nacional de Tucumán. Facultad de BioquÃmica, QuÃmica y Farmacia. Instituto de QuÃmica Biológica; ArgentinaFil: Saavedra, Maria Lucila. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin
NK cell-derived IL-10 is critical for DC-NK cell dialogue at the maternal- fetal interface
DC-NK cell interactions are thought to influence the development of maternal
tolerance and de novo angiogenesis during early gestation. However, it is
unclear which mechanism ensures the cooperative dialogue between DC and NK
cells at the feto-maternal interface. In this article, we show that uterine NK
cells are the key source of IL-10 that is required to regulate DC phenotype
and pregnancy success. Upon in vivo expansion of DC during early gestation, NK
cells expressed increased levels of IL-10. Exogenous administration of IL-10
was sufficient to overcome early pregnancy failure in dams treated to achieve
simultaneous DC expansion and NK cell depletion. Remarkably, DC expansion in
IL-10−/− dams provoked pregnancy loss, which could be abrogated by the
adoptive transfer of IL-10+/+ NK cells and not by IL-10−/− NK cells.
Furthermore, the IL-10 expressing NK cells markedly enhanced angiogenic
responses and placental development in DC expanded IL-10−/− dams. Thus, the
capacity of NK cells to secrete IL-10 plays a unique role facilitating the DC-
NK cell dialogue during the establishment of a healthy gestation
Tuning the pseudospin polarization of graphene by a pseudo-magnetic field
One of the intriguing characteristics of honeycomb lattices is the appearance
of a pseudo-magnetic field as a result of mechanical deformation. In the case
of graphene, the Landau quantization resulting from this pseudo-magnetic field
has been measured using scanning tunneling microscopy. Here we show that a
signature of the pseudo-magnetic field is a local sublattice symmetry breaking
observable as a redistribution of the local density of states. This can be
interpreted as a polarization of graphene's pseudospin due to a strain induced
pseudo-magnetic field, in analogy to the alignment of a real spin in a magnetic
field. We reveal this sublattice symmetry breaking by tunably straining
graphene using the tip of a scanning tunneling microscope. The tip locally
lifts the graphene membrane from a SiO support, as visible by an increased
slope of the curves. The amount of lifting is consistent with molecular
dynamics calculations, which reveal a deformed graphene area under the tip in
the shape of a Gaussian. The pseudo-magnetic field induced by the deformation
becomes visible as a sublattice symmetry breaking which scales with the lifting
height of the strained deformation and therefore with the pseudo-magnetic field
strength. Its magnitude is quantitatively reproduced by analytic and
tight-binding models, revealing fields of 1000 T. These results might be the
starting point for an effective THz valley filter, as a basic element of
valleytronics.Comment: Revised manuscript: streamlined the abstract and introduction, added
methods to supplement, Nano Letters, 201
Early expression of pregnancy-specific glycoprotein 22 (PSG22) by trophoblast cells modulates angiogenesis in mice.
Mouse and human pregnancy-specific glycoproteins (PSG) are known to exert immunomodulatory functions during pregnancy by inducing maternal leukocytes to secrete anti-inflammatory cytokines that promote a tolerogenic decidual microenvironment. Many such anti-inflammatory mediators also function as proangiogenic factors, which, along with the reported association of murine PSG with the uterine vasculature, suggest that PSG may contribute to the vascular adaptations necessary for successful implantation and placental development. We observed that PSG22 is strongly expressed around the embryonic crypt on Gestation Day 5.5, indicating that trophoblast giant cells are the main source of PSG22 during the early stages of pregnancy. PSG22 treatment up-regulated the secretion of transforming growth factor beta 1 and vascular endothelial growth factor A (VEGFA) in murine macrophages, uterine dendritic cells, and natural killer cells. A possible role of PSGs in uteroplacental angiogenesis is further supported by the finding that incubation of endothelial cells with PSG22 resulted in the formation of tubes in the presence and absence of VEGFA. We determined that PSG22, like human PSG1 and murine PSG17 and PSG23, binds to the heparan sulfate chains in syndecans. Therefore, our findings indicate that despite the independent evolution and expansion of human and rodent PSG, members in both families have conserved functions that include their ability to induce anti-inflammatory cytokines and proangiogenic factors as well as to induce the formation of capillary structures by endothelial cells. In summary, our results indicate that PSG22, the most abundant PSG expressed during mouse early pregnancy, is likely a major contributor to the establishment of a successful pregnancy.Fil: Blois, Sandra M.. University Medicine of Berlin; AlemaniaFil: Tirado González, Irene. University Medicine of Berlin; AlemaniaFil: Wu, Julie. Uniformed Services University of the Health Sciences; Estados UnidosFil: Barrientos, Gabriela Laura. University Medicine of Berlin; Alemania. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Johnson, Briana. Uniformed Services University of the Health Sciences; Estados UnidosFil: Warren, James. Uniformed Services University of the Health Sciences; Estados UnidosFil: Freitag, Nancy. University Medicine of Berlin; AlemaniaFil: Klapp, Burghard F.. University Medicine of Berlin; AlemaniaFil: Irmak, Ster. University of Duisburg Essen; AlemaniaFil: Ergun, Suleyman. Julius Maximilians Universitat Wurzburg. Biozentrum; AlemaniaFil: Dveskler, Gabriela S.. Uniformed Services University of the Health Sciences; Estados Unido
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