Reconciling different models of forebrain induction and patterning: a dual role for the hypoblast

Development ◽  
2000 ◽  
Vol 127 (17) ◽  
pp. 3839-3854 ◽  
Author(s):  
A.C. Foley ◽  
I. Skromne ◽  
C.D. Stern
Keyword(s):  
Nervous System ◽  
Molecular Markers ◽  
Regional Identity ◽  
Neural Tissue ◽  
Primitive Streak ◽  
Dual Role ◽  
Visceral Endoderm ◽  
Forebrain Development ◽  
Early Markers

Several models have been proposed for the generation of the rostral nervous system. Among them, Nieuwkoop's activation/transformation hypothesis and Spemann's idea of separate head and trunk/tail organizers have been particularly favoured recently. In the mouse, the finding that the visceral endoderm (VE) is required for forebrain development has been interpreted as support for the latter model. Here we argue that the chick hypoblast is equivalent to the mouse VE, based on fate, expression of molecular markers and characteristic anterior movements around the time of gastrulation. We show that the hypoblast does not fit the criteria for a head organizer because it does not induce neural tissue from naive epiblast, nor can it change the regional identity of neural tissue. However, the hypoblast does induce transient expression of the early markers Sox3 and Otx2. The spreading of the hypoblast also directs cell movements in the adjacent epiblast, such that the prospective forebrain is kept at a distance from the organizer at the tip of the primitive streak. We propose that this movement is important to protect the forebrain from the caudalizing influence of the organizer. This dual role of the hypoblast is more consistent with the Nieuwkoop model than with the notion of separate organizers, and accommodates the available data from mouse and other vertebrates.

scholarly journals Maternal Antiviral Immunoglobulin Accumulates in Neural Tissue of Neonates To Prevent HSV Neurological Disease

mBio ◽  
2017 ◽  
Vol 8 (4) ◽  
Author(s):  
Yike Jiang ◽  
Chaya D. Patel ◽  
Richard Manivanh ◽  
Brian North ◽  
Iara M. Backes ◽  
...  
Keyword(s):  
Nervous System ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Neural Tissue ◽  
Maternal Antibodies ◽  
Herpes Simplex Virus 1 ◽  
Maternal Immunization ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT While antibody responses to neurovirulent pathogens are critical for clearance, the extent to which antibodies access the nervous system to ameliorate infection is poorly understood. In this study on herpes simplex virus 1 (HSV-1), we demonstrate that HSV-specific antibodies are present during HSV-1 latency in the nervous systems of both mice and humans. We show that antibody-secreting cells entered the trigeminal ganglion (TG), a key site of HSV infection, and persisted long after the establishment of latent infection. We also demonstrate the ability of passively administered IgG to enter the TG independently of infection, showing that the naive TG is accessible to antibodies. The translational implication of this finding is that human fetal neural tissue could contain HSV-specific maternally derived antibodies. Exploring this possibility, we observed HSV-specific IgG in HSV DNA-negative human fetal TG, suggesting passive transfer of maternal immunity into the prenatal nervous system. To further investigate the role of maternal antibodies in the neonatal nervous system, we established a murine model to demonstrate that maternal IgG can access and persist in neonatal TG. This maternal antibody not only prevented disseminated infection but also completely protected the neonate from neurological disease and death following HSV challenge. Maternal antibodies therefore have a potent protective role in the neonatal nervous system against HSV infection. These findings strongly support the concept that prevention of prenatal and neonatal neurotropic infections can be achieved through maternal immunization. IMPORTANCE Herpes simplex virus 1 is a common infection of the nervous system that causes devastating neonatal disease. Using mouse and human tissue, we discovered that antiviral antibodies accumulate in neural tissue after HSV-1 infection in adults. Similarly, these antibodies pass to the offspring during pregnancy. We found that antiviral maternal antibodies can readily access neural tissue of the fetus and neonate. These maternal antibodies then protect neonatal mice against HSV-1 neurological infection and death. These results underscore the previously unappreciated role of maternal antibodies in protecting fetal and newborn nervous systems against infection. These data suggest that maternal immunization would be efficacious at preventing fetal/neonatal neurological infections. IMPORTANCE Herpes simplex virus 1 is a common infection of the nervous system that causes devastating neonatal disease. Using mouse and human tissue, we discovered that antiviral antibodies accumulate in neural tissue after HSV-1 infection in adults. Similarly, these antibodies pass to the offspring during pregnancy. We found that antiviral maternal antibodies can readily access neural tissue of the fetus and neonate. These maternal antibodies then protect neonatal mice against HSV-1 neurological infection and death. These results underscore the previously unappreciated role of maternal antibodies in protecting fetal and newborn nervous systems against infection. These data suggest that maternal immunization would be efficacious at preventing fetal/neonatal neurological infections.

The prechordal region lacks neural inducing ability, but can confer anterior character to more posterior neuroepithelium

Development ◽  
1997 ◽  
Vol 124 (15) ◽  
pp. 2983-2996 ◽  
Author(s):  
A.C. Foley ◽  
K.G. Storey ◽  
C.D. Stern
Keyword(s):  
Nervous System ◽  
Molecular Markers ◽  
Primitive Streak ◽  
Neural Fate ◽  
Spemann's Organizer ◽  
Stage 4

The avian equivalent of Spemann's organizer, Hensen's node, begins to lose its ability to induce a nervous system from area opaca epiblast cells at stage 4+, immediately after the full primitive streak stage. From this stage, the node is no longer able to induce regions of the nervous system anterior to the hindbrain. Stage 4+ is marked by the emergence from the node of a group of cells, the prechordal mesendoderm. Here we have investigated whether the prechordal region possesses the lost functions of the organizer, using quail-chick chimaeras to distinguish graft- and host-derived cells, together with several region-specific molecular markers. We find that the prechordal region does not have neural inducing ability, as it is unable to divert extraembryonic epiblast cells to a neural fate. However, it can confer more anterior character to prospective hindbrain cells of the host, making them acquire expression of the forebrain markers tailless and Otx-2. It can also rescue the expression of Krox-20 and Otx-2 from nervous system induced by an older (stage 5) node in extraembryonic epiblast. We show that these properties reflect a true change of fate of cells rather than recruitment from other regions. The competence of neuroectoderm to respond to anteriorizing signals declines by stages 7–9, but both posteriorizing signals and the ability of neuroectoderm to respond to them persist after this stage.

A possible dual role of noradrenaline in cardiovascular responses mediated by the central nervous system

1968 ◽  
Vol 46 (4) ◽  
pp. 595-599 ◽  
Author(s):  
D. J. Gagnon ◽  
K. I. Melville
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Artificial Respiration ◽  
Cardiovascular Responses ◽  
Dual Role ◽  
Neuronal Uptake ◽  
Reversal Phenomenon ◽  
The Central Nervous System ◽  
Uptake Of Noradrenaline

The cardiovascular responses induced by intraventricular noradrenaline after intraventricular pretreatment with reserpine, imipramine, and chlorpromazine were studied in cats anesthetized with chloralose and under artificial respiration. Pretreatment with all three agents produced various degrees of "reversal" of the usual cardiovascular depressant responses to noradrenaline (50 μg intraventricularly), leading to significant pressor responses and tachycardia. These sympathetic excitatory cardiovascular responses were significantly reduced by spinal C-2 section. It is suggested that this reversal phenomenon is not due entirely to brain noradrenaline depletion, but that all three agents (reserpine, imipramine, and chlorpromazine) act by blocking neuronal uptake of noradrenaline, thereby preventing the usual central cardiovascular inhibitory effects of the amine. These findings also suggest a possible dual role of noradrenaline in cardiovascular changes mediated by the central nervous system.

scholarly journals Cables2 Is a Novel Smad2-Regulatory Factor Essential for Early Embryonic Development in Mice

2019 ◽  
Author(s):  
Tra Thi Huong Dinh ◽  
Hiroyoshi Iseki ◽  
Seiya Mizuno ◽  
Saori Iijima-Mizuno ◽  
Yoko Tanimoto ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Expression Patterns ◽  
Physiological Role ◽  
Primitive Streak ◽  
Early Embryonic Development ◽  
Visceral Endoderm ◽  
Tetraploid Complementation ◽  
Mouse Tissues

ABSTRACTCDK5 and Abl enzyme substrate 2 (Cables2), a member of the Cables family that has a C-terminal cyclin box-like domain, is widely expressed in adult mouse tissues. However, the physiological role of Cables2 in vivo is unknown. We show here that Cables2-deficiency causes post-gastrulation embryonic lethality in mice. The mutant embryos progress to gastrulation, but then arrest, and fail to grow. Analysis of gene expression patterns reveals that formation of the anterior visceral endoderm and the primitive streak is impaired in Cables2-deficient embryos. Tetraploid complementation analyses support the critical requirement of Cables2 in both the epiblast and visceral endoderm for progression of embryogenesis. In addition, we show that Cables2 physically interacts with a key mediator of the canonical Nodal pathway, Smad2, and augments its transcriptional activity. These findings provide novel insights into the essential role of Cables2 in the early embryonic development in mice.

Axial mesendoderm refines rostrocaudal pattern in the chick nervous system

Development ◽  
1999 ◽  
Vol 126 (13) ◽  
pp. 2921-2934 ◽  
Author(s):  
A.M. Rowan ◽  
C.D. Stern ◽  
K.G. Storey
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Molecular Markers ◽  
Regional Differences ◽  
Normal Development ◽  
De Novo ◽  
Neural Plate ◽  
Large Panel ◽  
The Central Nervous System

There has long been controversy concerning the role of the axial mesoderm in the induction and rostrocaudal patterning of the vertebrate nervous system. Here we investigate the neural inducing and regionalising properties of defined rostrocaudal regions of head process/prospective notochord in the chick embryo by juxtaposing these tissues with extraembryonic epiblast or neural plate explants. We localise neural inducing signals to the emerging head process and using a large panel of region-specific neural markers, show that different rostrocaudal levels of the head process derived from headfold stage embryos can induce discrete regions of the central nervous system. However, we also find that rostral and caudal head process do not induce expression of any of these molecular markers in explants of the neural plate. During normal development the head process emerges beneath previously induced neural plate, which we show has already acquired some rostrocaudal character. Our findings therefore indicate that discrete regions of axial mesendoderm at headfold stages are not normally responsible for the establishment of rostrocaudal pattern in the neural plate. Strikingly however, we do find that caudal head process inhibits expression of rostral genes in neural plate explants. These findings indicate that despite the ability to induce specific rostrocaudal regions of the CNS de novo, signals provided by the discrete regions of axial mesendoderm do not appear to establish regional differences, but rather refine the rostrocaudal character of overlying neuroepithelium.

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