scholarly journals Delta-Notch Signaling: The Long and The Short of a Neuron’s Influence on Progenitor Fates

2020 ◽  
Vol 8 (2) ◽  
pp. 8 ◽  
Author(s):  
Rachel Moore ◽  
Paula Alexandre

Maintenance of the neural progenitor pool during embryonic development is essential to promote growth of the central nervous system (CNS). The CNS is initially formed by tightly compacted proliferative neuroepithelial cells that later acquire radial glial characteristics and continue to divide at the ventricular (apical) and pial (basal) surface of the neuroepithelium to generate neurons. While neural progenitors such as neuroepithelial cells and apical radial glia form strong connections with their neighbours at the apical and basal surfaces of the neuroepithelium, neurons usually form the mantle layer at the basal surface. This review will discuss the existing evidence that supports a role for neurons, from early stages of differentiation, in promoting progenitor cell fates in the vertebrates CNS, maintaining tissue homeostasis and regulating spatiotemporal patterning of neuronal differentiation through Delta-Notch signalling.

Author(s):  
Nicoletta Kessaris ◽  
Nigel Pringle ◽  
William D Richardson

All the neurons and glial cells of the central nervous system are generated from the neuroepithelial cells in the walls of the embryonic neural tube, the ‘embryonic neural stem cells’. The stem cells seem to be equivalent to the so-called ‘radial glial cells’, which for many years had been regarded as a specialized type of glial cell. These radial cells generate different classes of neurons in a position-dependent manner. They then switch to producing glial cells (oligodendrocytes and astrocytes). It is not known what drives the neuron–glial switch, although downregulation of pro-neural basic helix–loop–helix transcription factors is one important step. This drives the stem cells from a neurogenic towards a gliogenic mode. The stem cells then choose between developing as oligodendrocytes or astrocytes, of which there might be intrinsically different subclasses. This review focuses on the different extracellular signals and intracellular responses that influence glial generation and the choice between oligodendrocyte and astrocyte fates.


2017 ◽  
Author(s):  
Olga Zueva ◽  
Maleana Khoury ◽  
Thomas Heinzeller ◽  
Daria Mashanova ◽  
Vladimir Mashanov

AbstractBrittle stars (Ophiuroidea, Echinodermata) have been increasingly used in studies of animal behavior, locomotion, regeneration, physiology, and bioluminescence. The success of these studies directly depends on good working knowledge of ophiuroid nervous system. Here, we describe the arm nervous system at different levels of organization: microanatomy of the radial nerve cord and peripheral nerves, neural ultrastructure, and localization of different cell types using specific antibody markers. We standardize the nomenclature of nerves and ganglia and provide an anatomically accurate digital 3D model of the arm nervous system as a reference for future studies. Our results helped identify several general features characteristic to the adult echinoderm nervous system, including the extensive anatomical interconnections between the ectoneural and hyponeural components and neuroepithelial organization of the central nervous system with its supporting scaffold formed by radial glial cells. In addition, we provide further support to the notion that the echinoderm radial glia is a complex and diverse cell population. We also tested the suitability of a range of specific cell-type markers for studies of the brittle star nervous system and established that the radial glial cells are reliably labeled by the ERG1 antibodies, whereas the best neuronal markers are acetylated tubulin, ELAV and synaptotagmin B. The transcription factor Brn1/2/4, a marker of neuronal progenitors, is expressed not only in neurons, but also in a subpopulation of radial glia. For the first time, we describe putative ophiuroid proprioceptors associated with the hyponeural part of the central nervous system.


Author(s):  
Ugomma C. Eze ◽  
Aparna Bhaduri ◽  
Maximilian Haeussler ◽  
Tomasz J. Nowakowski ◽  
Arnold R. Kriegstein

AbstractThe human cortex comprises diverse cell types that emerge from an initially uniform neuroepithelium that gives rise to radial glia, the neural stem cells of the cortex. To characterize the earliest stages of human brain development, we performed single-cell RNA-sequencing across regions of the developing human brain, including the telencephalon, diencephalon, midbrain, hindbrain and cerebellum. We identify nine progenitor populations physically proximal to the telencephalon, suggesting more heterogeneity than previously described, including a highly prevalent mesenchymal-like population that disappears once neurogenesis begins. Comparison of human and mouse progenitor populations at corresponding stages identifies two progenitor clusters that are enriched in the early stages of human cortical development. We also find that organoid systems display low fidelity to neuroepithelial and early radial glia cell types, but improve as neurogenesis progresses. Overall, we provide a comprehensive molecular and spatial atlas of early stages of human brain and cortical development.


Author(s):  
Yuki Shimizu ◽  
Takashi Kawasaki

Zebrafish have superior regenerative capacity in the central nervous system (CNS) compared to mammals. In contrast, medaka were shown to have low regenerative capacity in the adult heart and larval retina, despite the well-documented high tissue regenerative ability of teleosts. Nevertheless, medaka and zebrafish share similar brain structures and biological features to those of mammals. Hence, this study aimed to compare the neural stem cell (NSC) responses and regenerative capacity in the optic tectum of adult medaka and zebrafish after stab wound injury. Limited neuronal differentiation was observed in the injured medaka, though the proliferation of radial glia (RG) was induced in response to tectum injury. Moreover, the expression of the pro-regenerative transcriptional factors ascl1a and oct4 was not enhanced in the injured medaka, unlike in zebrafish, whereas expression of sox2 and stat3 was upregulated in both fish models. Of note, glial scar-like structures composed of GFAP+ radial fibers were observed in the injured area of medaka at 14 days post injury (dpi). Altogether, these findings suggest that the adult medaka brain has low regenerative capacity with limited neuronal generation and scar formation. Hence, medaka represent an attractive model for investigating and evaluating critical factors for brain regeneration.


2020 ◽  
Author(s):  
Zhongfu Shen ◽  
Yang Lin ◽  
Jiajun Yang ◽  
David J. Jörg ◽  
Yuwei Peng ◽  
...  

SUMMARYRadial glial progenitors (RGPs) are responsible for producing the vast majority of neurons and glia in the neocortex. While RGP behavior and progressive generation of neocortical neurons have been delineated, the exact process of neocortical gliogenesis remains elusive. Here, we report the precise progenitor cell behavior and gliogenesis program at single-cell resolution in the mouse neocortex. RGPs transition from neurogenesis to gliogenesis progressively, producing astrocytes, oligodendrocytes, or both in well-defined propensities of 60%:15%:25%, respectively, via fate-restricted “intermediate” precursor cells. While the total number of precursor cells generated by individual RGPs appears stochastic, the output of individual precursor cells exhibit clear patterns in number and subtype, and form discrete local subclusters. Clonal loss of tumor suppressor Neurofibromatosis type 1 leads to excessive production of glia selectively, especially oligodendrocyte precursor cells. These results delineate the cellular program of neocortical gliogenesis quantitatively and suggest the cellular and lineage origin of primary brain tumor.


2004 ◽  
Vol 19 (3) ◽  
pp. 274-279
Author(s):  
Shigeaki Kanatani ◽  
Hidenori Tabata ◽  
Kazunori Nakajima

Cortical formation in the developing brain is a highly complicated process involving neuronal production (through symmetric or asymmetric cell division) interaction of radial glia with neuronal migration, and multiple modes of neuronal migration. It has been convincingly demonstrated by numerous studies that radial glial cells are neural stem cells. However, the processes by which neurons arise from radial glia and migrate to their final destinations in vivo are not yet fully understood. Recent studies using time-lapse imaging of neuronal migration are giving investigators an increasingly more detailed understanding of the mitotic behavior of radial glia and the migrating behavior of their daughter cells. In this review, we describe recent progress in elucidating neuronal migration in brain formation and how neuronal migration is disturbed by mutations in genes that control this process. ( J Child Neurol 2005;20:274—279).


Development ◽  
1997 ◽  
Vol 124 (17) ◽  
pp. 3283-3291 ◽  
Author(s):  
S.S. Huppert ◽  
T.L. Jacobsen ◽  
M.A. Muskavitch

Delta and Notch are required for partitioning of vein and intervein cell fates within the provein during Drosophila metamorphosis. We find that partitioning of these fates is dependent on Delta-mediated signalling from 22 to 30 hours after puparium formation at 25 degrees C. Within the provein, Delta is expressed more highly in central provein cells (presumptive vein cells) and Notch is expressed more highly in lateral provein cells (presumptive intervein cells). Accumulation of Notch in presumptive intervein cells is dependent on Delta signalling activity in presumptive vein cells and constitutive Notch receptor activity represses Delta accumulation in presumptive vein cells. When Delta protein expression is elevated ectopically in presumptive intervein cells, complementary Delta and Notch expression patterns in provein cells are reversed, and vein loss occurs because central provein cells are unable to stably adopt the vein cell fate. Our findings imply that Delta-Notch signalling exerts feedback regulation on Delta and Notch expression during metamorphic wing vein development, and that the resultant asymmetries in Delta and Notch expression underlie the proper specification of vein and intervein cell fates within the provein.


Development ◽  
1999 ◽  
Vol 126 (11) ◽  
pp. 2355-2364 ◽  
Author(s):  
M. Llimargas

The Drosophila tracheal system consists of a stereotyped network of epithelial tubes formed by several tracheal cell types. By the end of embryogenesis, when the general branching pattern is established, some specialised tracheal cells then mediate branch fusion while others extend fine terminal branches. Here evidence is presented that the Notch signalling pathway acts directly in the tracheal cells to distinguish individual fates within groups of equivalent cells. Notch helps to single out those tracheal cells that mediate branch fusion by blocking their neighbours from adopting the same fate. This function of Notch would require the restricted activation of the pathway in specific cells. In addition, and probably later, Notch also acts in the selection of those tracheal cells that extend the terminal branches. Both the localised expression and the mutant phenotypes of Delta, a known ligand for Notch, suggest that Delta may activate Notch to specify cell fates at the tips of the developing tracheal branches.


2019 ◽  
Vol 13 (9) ◽  
pp. 1724-1731 ◽  
Author(s):  
Maria Giovanna Francipane ◽  
Bing Han ◽  
Leif Oxburgh ◽  
Sunder Sims‐Lucas ◽  
Zhongwei Li ◽  
...  

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