RESUMO
Bacterial infection alters placental ABC transporters expression. These transporters provide fetal protection against circulating xenobiotics and environmental toxins present in maternal blood. We hypothesized that lipopolysaccharide (LPS-bacterial mimic) alters the yolk sac morphology and expression of key ABC transporters in a gestational-age dependent manner. Yolk sac samples from C57BL/6 mice were obtained at gestational ages (GD) 15.5 and GD18.5, 4 or 24 h after LPS exposure (150ug/kg; n = 8/group). Samples underwent morphometrical, qPCR and immunohistochemistry analysis. The volumetric proportions of the histological components of the yolk sac did not change in response to LPS. LPS increased Abcg2 expression at GD15.5, after 4 h of treatment (p < 0.05). No changes in Abca1, Abcb1a/b, Abcg1, Glut1, Snat1, Il-1ß, Ccl2 and Mif were observed. Il-6 and Cxcl1 were undetectable in the yolk sac throughout pregnancy. Abca1, breast cancer resistance protein (Bcrp, encoded by Abcg2) and P-glycoprotein (P-gp/ Abcb1a/b) were localized in the endodermal (uterine-facing) epithelium and to a lesser extent in the mesothelium (amnion-facing), whereas Abca1 was also localized to the endothelium of the yolk sac blood vessels. LPS increased the labeling area and intensity of Bcrp in the yolk sac's mesothelial cells at GD15.5 (4 h), whereas at GD18.5, the area of Bcrp labeling in the mesothelium (4 and 24 h) was decreased (p < 0.05). Bacterial infection has the potential to change yolk sac barrier function by affecting Bcrp and Abcg2 expression in a gestational-age dependent-manner. These changes may alter fetal exposure to xenobiotics and toxic substances present in the maternal circulation and in the uterine cavity.
Assuntos
Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Lipopolissacarídeos/farmacologia , Saco Vitelino/efeitos dos fármacos , Animais , Feminino , Idade Gestacional , Camundongos Endogâmicos C57BL , Gravidez , Saco Vitelino/metabolismoRESUMO
Malaria in pregnancy (MiP) induces intrauterine growth restriction (IUGR) and preterm labour (PTL). However, its effects on yolk sac morphology and function are largely unexplored. We hypothesized that MiP modifies yolk sac morphology and efflux transport potential by modulating ABC efflux transporters. C57BL/6 mice injected with Plasmodium berghei ANKA (5 × 105 infected erythrocytes) at gestational day (GD) 13.5 were subjected to yolk sac membrane harvesting at GD 18.5 for histology, qPCR and immunohistochemistry. MiP did not alter the volumetric proportion of the yolk sac's histological components. However, it increased levels of Abcb1a mRNA (encoding P-glycoprotein) and macrophage migration inhibitory factor (Mif chemokine), while decreasing Abcg1 (P < 0.05); without altering Abca1, Abcb1b, Abcg2, Snat1, Snat2, interleukin (Il)-1ß and C-C Motif chemokine ligand 2 (Ccl2). Transcripts of Il-6, chemokine (C-X-C motif) ligand 1 (Cxcl1), Glut1 and Snat4 were not detectible. ABCA1, ABCG1, breast cancer resistance protein (BCRP) and P-gp were primarily immunolocalized to the cell membranes and cytoplasm of endodermic epithelium but also in the mesothelium and in the endothelium of mesodermic blood vessels. Intensity of P-gp labelling was stronger in both endodermic epithelium and mesothelium, whereas ABCA1 labelling increased in the endothelium of the mesodermic blood vessels. The presence of ABC transporters in the yolk sac wall suggests that this fetal membrane acts as an important protective gestational barrier. Changes in ABCA1 and P-gp in MiP may alter the biodistribution of toxic substances, xenobiotics, nutrients and immunological factors within the fetal compartment and participate in the pathogenesis of malaria-induced IUGR and PTL.
Assuntos
Transportador 1 de Cassete de Ligação de ATP/biossíntese , Subfamília B de Transportador de Cassetes de Ligação de ATP/biossíntese , Regulação da Expressão Gênica , Malária/metabolismo , Complicações Infecciosas na Gravidez/metabolismo , Saco Vitelino/metabolismo , Transportador 1 de Cassete de Ligação de ATP/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Animais , Transporte Biológico , Citocinas/biossíntese , Citocinas/genética , Feminino , Retardo do Crescimento Fetal/etiologia , Inflamação , Malária/complicações , Malária/genética , Proteínas de Membrana Transportadoras/biossíntese , Proteínas de Membrana Transportadoras/genética , Camundongos , Camundongos Endogâmicos C57BL , Tamanho do Órgão , Plasmodium berghei , Gravidez , Complicações Infecciosas na Gravidez/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Saco Vitelino/ultraestruturaRESUMO
SR-BI is the main receptor for high density lipoproteins (HDL) and mediates the bidirectional transport of lipids, such as cholesterol and vitamin E, between these particles and cells. During early development, SR-BI is expressed in extraembryonic tissue, specifically in trophoblast giant cells in the parietal yolk sac. We previously showed that approximately 50% of SR-BI-/- embryos fail to close the anterior neural tube and develop exencephaly, a perinatal lethal condition. Here, we evaluated the role of SR-BI in embryonic vitamin E uptake during murine neural tube closure. Our results showed that SR-BI-/- embryos had a very low vitamin E content in comparison to SR-BI+/+ embryos. Whereas SR-BI-/- embryos with closed neural tubes (nSR-BI-/-) had high levels of reactive oxygen species (ROS), intermediate ROS levels between SR-BI+/+ and nSR-BI-/- embryos were detected in SR-BI-/- with NTD (NTD SR-BI-/-). Reduced expression of Pax3, Alx1 and Alx3 genes was found in NTD SR-BI-/- embryos. Maternal α-tocopherol dietary supplementation prevented NTD almost completely (from 54% to 2%, p < 0.001) in SR-BI-/- embryos and normalized ROS and gene expression levels. In sum, our results suggest the involvement of SR-BI in the maternal provision of embryonic vitamin E to the mouse embryo during neural tube closure.
Assuntos
Antígenos CD36/deficiência , Desenvolvimento Embrionário , Tubo Neural/embriologia , Tubo Neural/metabolismo , Vitamina E/metabolismo , Animais , Biomarcadores , Suplementos Nutricionais , Desenvolvimento Embrionário/genética , Regulação da Expressão Gênica no Desenvolvimento , Camundongos , Camundongos Knockout , Oxirredução , Saco Vitelino/embriologia , Saco Vitelino/metabolismo , alfa-Tocoferol/administração & dosagemRESUMO
Early development from the egg fertilization to complete resorption of the yolk-sac is a critical period in the life cycle of teleost fish. Knowledge of this process provides essential parameters for aquaculture and identification of spawning sites in the wild. In the present study, a comparative morphological analysis of the oocyte surface as well as early development was performed in four commercially valuable species from the São Francisco River: Brycon orthotaenia, Leporinus obtusidens, Prochilodus argenteus, and Salminus franciscanus. Stripped oocytes, embryo, and yolk-sac larvae were analyzed by scanning electron microscopy (SEM) and histology. A set of 10 lectins was used for investigation of lectin-binding pattern in oocytes. In the four species, the outer layer of the zona radiata reacted to most lectins, indicating complex polysaccharides at the oocyte surface while no reactivity was detected in the inner zona radiata and yolk globules. Typical structural arrangements were recognized at the micropylar region by SEM. The four species showed nonadhesive eggs, short embryonic period (18-20 h at 24 ± 1°C), and poorly developed larvae at hatching. At 24 h posthatching (hph), larvae of the four species had neuromasts on the body surface. Rudimentary cement glands for larval attachment were identified on the cephalic region at 24 and 48 hph in B. orthotaenia and S. franciscanus, and following they were in regression. The time for whole yolk resorption varied among species from 48 to 120 hph, occurring earlier in S. franciscanus, followed by B. orthotaenia, P. argenteus, and L. obtusidens. The formation of the digestive tract and the mouth opening indicated initiation of exogenous feeding 24 h before complete resorption of the yolk. Together, our data indicate similarities in the early development among species that may be related to the life cycle strategies and phylogeny.
Assuntos
Characidae/embriologia , Oócitos/ultraestrutura , Animais , Brasil , Characidae/metabolismo , Larva/metabolismo , Larva/ultraestrutura , Oócitos/metabolismo , Saco Vitelino/metabolismo , Saco Vitelino/ultraestruturaRESUMO
Omentin-1 is an adipocytokine with anti-inflammatory activity that has been associated with different metabolic disorders. The aim of this study is to investigate the serum profiles of omentin-1 throughout human and rat pregnancy. Serum omentin-1 levels were determined by ELISA in a prospective cohort study of healthy pregnant women (n=40) during the three trimesters of pregnancy and in twenty healthy non-pregnant women during the follicular and luteal phase of the menstrual cycle. In addition, serum omentin-1 levels were measured in rats during different periods of pregnancy (gestational days 8, 12, 16, 19, and 21) and in an age-matched control (virgin) group of rats (n=12rats/group). Finally, immunohistochemistry was used to demonstrate the presence of omentin-1 protein in human and rat placenta. Omentin-1 immunoreactivity was detected in cytotrophoblasts, syncytiotrophoblasts, sparse Hofbauer cells, and endothelial cells of the stem villi of human placenta. Additionally, it was detected in the labyrinthine trophoblast and yolk sac layer of the rat placenta. Human and rat serum omentin-1 levels were significantly lower in the late gestational period when compared with the non-pregnant women and virgin rats (p<0.05). Serum omentin-1 changes were not significant throughout the gestation in both species (p>0.05). Human serum omentin-1 levels have an inverse relationship with triglyceride levels during pregnancy. Our findings have not determined the exact role of omentin-1 during pregnancy, concerning the metabolic control of triglycerides and other energy sources. Whether omentin-1 decrease implies a regulatory function is still not clear. Further studies are needed to address this issue and determine the role of omentin-1 in metabolic adaptations during normal human and rat pregnancy.
Assuntos
Citocinas/sangue , Regulação da Expressão Gênica no Desenvolvimento , Lectinas/sangue , Adulto , Animais , Vilosidades Coriônicas/metabolismo , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Ensaio de Imunoadsorção Enzimática , Feminino , Proteínas Ligadas por GPI/sangue , Humanos , Imuno-Histoquímica , Gravidez , Prenhez , Ratos , Ratos Sprague-Dawley , Fatores de Tempo , Triglicerídeos/metabolismo , Trofoblastos/metabolismo , Saco Vitelino/metabolismo , Adulto JovemRESUMO
In several species, placentation involves the presence of two different membranes responsible for maternal-fetal exchanges: the yolk sac and the chorioallantoic placenta. The yolk sac plays important roles in embryonic survival, mainly during the early stages of gestation. In bovine, it is a transitional membrane that is present until day 50-70 of pregnancy. Herein, we evaluated the morphological and molecular aspects of the yolk sac of bovine embryos during 24 to 52 days of gestation. A total of 69 embryos were allocated into three groups according to the crown-rump length and estimated ages. Yolk sac samples were then subjected to morphological and molecular analysis using mass spectrometry and nuclear magnetic resonance techniques. In contrast to alanine, which was observed only in Group I, during all gestational stages, we identified important metabolites such as aspartate, taurine, glycerophosphocholine, creatinine, creatine, hydrouracil, glutamate, glutamine, lactate, lysine, valine, myo-inositol, cadaverine, and choline. In addition, 314 random sequences of proteins were identified in the bovine yolk sac, and 47 of these were considered to be specific. Changes in alpha-fetoprotein and carcinoembryonic antigen concentrations during gestation were also evaluated. In conclusion, the majority of these proteins are related to the development of secondary metabolites that are involved in the activation of other proteins and metabolites, and in signaling pathways that are responsible for maternal-fetal exchanges, activation of programmed cell death mechanisms, and cellular differentiation, and also in proteins that are responsible for the yolk sac involution that is required to establish chorioallantoic placentation.
Assuntos
Metabolômica , Proteoma/genética , Saco Vitelino/metabolismo , Aminoácidos/metabolismo , Animais , Bovinos , Feminino , Placenta/metabolismo , Gravidez , Biossíntese de Proteínas/genética , Proteoma/metabolismoRESUMO
The endodermal cells of the human yolk sac (YS) produce non-nucleated erythrocytes (NNEs) and numerous serum proteins that are transiently storage within the YS cavity. After their transfer via the vitelline duct to the embryo gastrointestinal lumen, the nutrients' final fate is unknown. With the aim of investigate how erythroid cells and nutrients are conveyed to embryo circulation, we studied, using a morphological and immunohistochemical approach, the embryo anatomy and the serum protein α-fetoprotein (AFP) presence, in 15 human embryos and their YS, collected from tubal pregnancies from 4 to 8 wpf. We observed at 5 wpf, a strong AFP staining in the endodermal cells of the YS, thereafter AFP was only present in the YS cavity and the gastrointestinal lumen. During 7 wpf, AFP expression declined and disappeared, concomitant with YS regression. Between 5 and 7 wpf, NNEs were observed in the gastrointestinal cavity, where they accumulate in the stomach. Here, the cells were attached to the endodermal epithelial cells or were free in the lumen. By scanning electron microscopy, we identified signs of NNEs phagocytized by endodermal cells. Those NNEs free in the lumen, after hemolysis, were probably removed by endocytosis (cell debris). Taking all together, we postulate that after reaching the endodermal epithelial cells of the stomach, nutrients are transferred to the embryo by a phagocytic/endocytic mechanism that is operative until the end of 6 wpf. After absorption, NNEs are probably degraded within phagosomes, nutrients delivered to the cell cytoplasm and then transported towards the embryonic circulation.
Assuntos
Embrião de Mamíferos/metabolismo , Trato Gastrointestinal/embriologia , Fenômenos Fisiológicos da Nutrição , Saco Vitelino/metabolismo , Embrião de Mamíferos/ultraestrutura , Desenvolvimento Embrionário , Eritrócitos/metabolismo , Trato Gastrointestinal/metabolismo , Humanos , Imuno-Histoquímica , Microscopia Eletrônica de Varredura , Fagocitose , alfa-Fetoproteínas/metabolismoRESUMO
The yolk sac is an embryonic membrane that is essential for the embryo's initial survival in many mammals. It also plays an important role in the production of proteins necessary for development. We studied proteins of the yolk sac in bovine embryos at up to 40 days of gestation. We examined the yolk sac of 17 bovine embryos at different gestational periods, measuring α-fetoprotein, α-1-antitrypsin, and transferrin. This experiment was carried out by Western blot technique, associated with electrophoresis on a 6% sodium dodecyl sulfate polyacrylamide gel. Mouse monoclonal antibody anti-human-α-fetoprotein, mouse antibody anti-human-transferrin and rabbit polyclonal anti-human-α-1-antitrypsin were used as primary antibodies, and conjugated peroxidase as a secondary antibody. We detected the three proteins in some of the yolk sac samples; however, the bands in some specimens (samples) were weak, maybe a result of poor antigen-antibody reaction, since the antibodies used in this study were not specific to bovine proteins. The fact that weak bands appeared might be due to a weak cross-reaction.
Assuntos
Proteínas do Ovo/metabolismo , Saco Vitelino/embriologia , Saco Vitelino/metabolismo , Animais , Bovinos , Técnicas Eletroquímicas , Feminino , Humanos , Medições Luminescentes , Peso MolecularRESUMO
Development within the cleidoic egg of birds and reptiles presents the embryo with the problem of accumulation of wastes from nitrogen metabolism. Ammonia derived from protein catabolism is converted into the less toxic product urea or relatively insoluble uric acid. The pattern of nitrogen excretion of the green iguana, Iguana iguana, was determined during embryonic development using samples from allantoic fluid and from the whole homogenized egg, and in hatchlings and adults using samples of blood plasma. Urea was the major excretory product over the course of embryonic development. It was found in higher concentrations in the allantoic sac, suggesting that there is a mechanism present on the allantoic membrane enabling the concentration of urea. The newly hatched iguana still produced urea while adults produced uric acid. The time course of this shift in the type of nitrogen waste was not determined but the change is likely to be related to the water relations associated with the terrestrial habit of the adult. The green iguana produces parchment-shelled eggs that double in mass during incubation due to water absorption; the eggs also accumulate 0.02 mM of urea, representing 82% of the total measured nitrogenous residues that accumulate inside the allantois. The increase in egg mass and urea concentration became significant after 55 days of incubation then were unchanged until hatching.