scholarly journals 6B4 proteoglycan/phosphacan is a repulsive substratum but promotes morphological differentiation of cortical neurons

Development ◽  
1996 ◽  
Vol 122 (2) ◽  
pp. 647-658
Author(s):  
N. Maeda ◽  
M. Noda
Keyword(s):  
Cell Adhesion ◽  
Neurite Outgrowth ◽  
Cortical Neurons ◽  
Tyrosine Phosphatase ◽  
Neuronal Cell ◽  
Morphological Differentiation ◽  
Cell Types ◽  
Thalamic Neurons ◽  
Neurite Extension ◽  
The Brain

6B4 proteoglycan/phosphacan is one of the major phosphate-buffered saline-soluble chondroitin sulfate proteoglycans of the brain. Recently, this molecule has been demonstrated to be an extracellular variant of the proteoglycan-type protein tyrosine phosphatase, PTPzeta (RPTPbeta). The influence of the 6B4 proteoglycan, adsorbed onto the substratum, on cell adhesion and neurite outgrowth was studied using dissociated neurons from the cerebral cortex and thalamus. 6B4 proteoglycan adsorbed onto plastic tissue culture dishes did not support neuronal cell adhesion, but rather exerted repulsive effects on cortical and thalamic neurons. When neurons were densely seeded on patterned substrata consisting of a grid-like structure of alternating poly-L-lysine and 6B4 proteoglycan-coated poly-L-lysine domains, they were concentrated on the poly-L-lysine domains. However, 6B4 proteoglycan did not retard the differentiation of neurons but rather promoted neurite outgrowth and development of the dendrites of cortical neurons, when neurons were sparsely seeded on poly-L-lysine-conditioned coverslips continuously coated with 6B4 proteoglycan. This effect of 6B4 proteoglycan on the neurite extension of cortical neurons was apparent even on coverslips co-coated with fibronectin or tenascin. By contrast, the neurite extension of thalamic neurons was not modified by 6B4 proteoglycan. Chondroitinase ABC or keratanase digestion of 6B4 proteoglycan did not affect its neurite outgrowth promoting activity, but a polyclonal antibody against 6B4 proteoglycan completely suppressed this activity, suggesting that a protein moiety is responsible for the activity. 6B4 proteoglycan transiently promoted tyrosine phosphorylation of an 85x10(3) Mr protein in the cortical neurons, which correlated with the induction of neurite outgrowth. These results suggest that 6B4 proteoglycan/phosphacan modulates morphogenesis and differentiation of neurons dependent on its spatiotemporal distribution and the cell types in the brain.

Effect of elevated potassium on the ion content of mouse astrocytes and neurons

1992 ◽  
Vol 70 (S1) ◽  
pp. S263-S268 ◽  
Author(s):  
H. Steve White ◽  
Sien Yao Chow ◽  
Y. C. Yen-Chow ◽  
Dixon M. Woodbury
Keyword(s):  
Cortical Neurons ◽  
Cell Types ◽  
Mouse Cell ◽  
Ion Concentration ◽  
Cellular Heterogeneity ◽  
Resting Membrane Potential ◽  
Extracellular Potassium ◽  
Individual Response ◽  
Extracellular Potassium Concentration ◽  
The Brain

Potassium is tightly regulated within the extracellular compartment of the brain. Nonetheless, it can increase 3- to 4-fold during periods of intense seizure activity and 10- to 20-fold under certain pathological conditions such as spreading depression. Within the central nervous system, neurons and astrocytes are both affected by shifts in the extracellular concentration of potassium. Elevated potassium can lead to a redistribution of other ions (e.g., calcium, sodium, chloride, hydrogen, etc.) within the cellular compartment of the brain. Small shifts in the extracellular potassium concentration can markedly affect acid–base homeostasis, energy metabolism, and volume regulation of these two brain cells. Since normal neuronal function is tightly coupled to the ability of the surrounding glial cells to regulate ionic shifts within the brain and since both cell types can be affected by shifts in the extracellular potassium, it is important to characterize their individual response to an elevation of this ion. This review describes the results of side-by-side studies conducted on cortical neurons and astrocytes, which assessed the effect of elevated potassium on their resting membrane potential, intracellular volume, and their intracellular concentration of potassium, sodium, and chloride. The results obtained from these studies suggest that there exists a marked cellular heterogeneity between neurons and astrocytes in their response to an elevation in the extracellular potassium concentration.Key words: astrocytes, neurons, ion concentration, neuronal–glial interactions, mouse, cell culture.

Retinal input influences pace of neurogenesis but not cell-type configuration of the visual forebrain

2021 ◽  
Author(s):  
Shachar Sherman ◽  
Koichi Kawakami ◽  
Herwig Baier
Keyword(s):  
Visual Information ◽  
Visual Stimulation ◽  
Ganglion Cells ◽  
Neuronal Cell ◽  
Cell Types ◽  
Vertebrate Brain ◽  
Relative Contribution ◽  
Retinal Input ◽  
And Migration ◽  
The Brain

The brain is assembled during development by both innate and experience-dependent mechanisms1-7, but the relative contribution of these factors is poorly understood. Axons of retinal ganglion cells (RGCs) connect the eye to the brain, forming a bottleneck for the transmission of visual information to central visual areas. RGCs secrete molecules from their axons that control proliferation, differentiation and migration of downstream components7-9. Spontaneously generated waves of retinal activity, but also intense visual stimulation, can entrain responses of RGCs10 and central neurons11-16. Here we asked how the cellular composition of central targets is altered in a vertebrate brain that is depleted of retinal input throughout development. For this, we first established a molecular catalog17 and gene expression atlas18 of neuronal subpopulations in the retinorecipient areas of larval zebrafish. We then searched for changes in lakritz (atoh7-) mutants, in which RGCs do not form19. Although individual forebrain-expressed genes are dysregulated in lakritz mutants, the complete set of 77 putative neuronal cell types in thalamus, pretectum and tectum are present. While neurogenesis and differentiation trajectories are overall unaltered, a greater proportion of cells remain in an uncommitted progenitor stage in the mutant. Optogenetic stimulation of a pretectal area20,21 evokes a visual behavior in blind mutants indistinguishable from wildtype. Our analysis shows that, in this vertebrate visual system, neurons are produced more slowly, but specified and wired up in a proper configuration in the absence of any retinal signals.

scholarly journals Neuronal apoptosis: signal and cell diversity

1969 ◽  
Vol 40 (1) ◽  
pp. 124-133
Author(s):  
Lina Vanessa Becerra ◽  
Hernán José Pimienta
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Neuronal Response ◽  
Neuronal Cell ◽  
Cell Types ◽  
Point Of View ◽  
Trophic Factors ◽  
Cell Diversity ◽  
Apoptotic Pathways ◽  
The Brain

Programmed cell death occurs as a physiological process during development. In the brain and spinal cord this event determines the number and location of the different cell types. In adulthood, programmed cell death or apoptosis is more restricted but it may play a major role in different acute and chronic pathological entities. However, in contrast to other tissues where apoptosis has been widely documented from a morphological point of view, in the central nervous system complete anatomical evidence of apoptosis is scanty. In spite of this there is consensus about the activation of different signal systems associated to programmed cell death. In the present article we attempt to summarize the main apoptotic pathways so far identified in nervous tissue. Considering that apoptotic pathways are multiple, the neuronal cell types are highly diverse and specialized and that neuronal response to injury and survival depends upon tissue context, (i.e., preservation of connectivity, glial integrity and cell matrix, blood supply and trophic factors availability) what is relevant for the apoptotic process in a sector of the brain may not be important in another.

Form and Function in Cells of the Brain

The Neuron ◽  
2015 ◽  
pp. 23-38
Author(s):  
Irwin B. Levitan ◽  
Leonard K. Kaczmarek
Keyword(s):  
Axonal Transport ◽  
Molecular Motors ◽  
Critical Role ◽  
Neuronal Cell ◽  
Cell Types ◽  
Neuronal Cell Body ◽  
Long Distance ◽  
Form And Function ◽  
And Function ◽  
The Brain

This chapter examines unique mechanisms that the neuron has evolved to establish and maintain the form required for its specialized signaling functions. Unlike some other organs, the brain contains a variety of cell types including several classes of glial cells, which play a critical role in the formation of the myelin sheath around axons and may be involved in immune responses, synaptic transmission, and long-distance calcium signaling in the brain. Neurons share many features in common with other cells (including glia), but they are distinguished by their highly asymmetrical shapes. The neuronal cytoskeleton is essential for establishing this cell shape during development and for maintaining it in adulthood. The process of axonal transport moves vesicles and other organelles to regions remote from the neuronal cell body. Proteins such as kinesin and dynein, called molecular motors, make use of the energy released by hydrolysis of ATP to drive axonal transport.

scholarly journals Heme–Hemopexin Complex Attenuates Neuronal Cell Death and Stroke Damage

2009 ◽  
Vol 29 (5) ◽  
pp. 953-964 ◽  
Author(s):  
Rung-chi Li ◽  
Sofiyan Saleem ◽  
Gehua Zhen ◽  
Wangsen Cao ◽  
Hean Zhuang ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Artery Occlusion ◽  
Neuronal Cultures ◽  
Tert Butyl Hydroperoxide ◽  
Primary Mouse ◽  
Free Heme ◽  
Cerebral Artery Occlusion ◽  
The Brain

Hemoproteins undergo degradation during hypoxic/ischemic conditions, but the prooxidant free heme that is released cannot be recycled and must be degraded. The extracellular heme associates with its high-affinity binding protein, hemopexin (HPX). Hemopexin is shown here to be expressed by cortical neurons and it is present in mouse cerebellum, cortex, hippocampus, and striatum. Using the transient ischemia model (90-min middle cerebral artery occlusion followed by 96-h survival), we provide evidence that HPX is protective in the brain, as neurologic deficits and infarct volumes were significantly greater in HPX−/− than in wild-type mice. Addressing the potential protective HPX cellular pathway, we observed that exogenous free heme decreased cell survival in primary mouse cortical neuron cultures, whereas the heme bound to HPX was not toxic. Heme-HPX complexes induce HO1 and, consequently, protect primary neurons against the toxicity of both heme and prooxidant tert-butyl hydroperoxide; such protection was decreased in HO1−/− neuronal cultures. Taken together, these data show that HPX protects against heme-induced toxicity and oxidative stress and that HO1 is required. We propose that the heme-HPX system protects against stroke-related damage by maintaining a tight balance between free and bound heme. Thus, regulating extracellular free heme levels, such as with HPX, could be neuroprotective.

scholarly journals Consistent cross-modal identification of cortical neurons with coupled autoencoders

2020 ◽  
Author(s):  
Rohan Gala ◽  
Agata Budzillo ◽  
Fahimeh Baftizadeh ◽  
Jeremy Miller ◽  
Nathan Gouwens ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Neuronal Cell ◽  
Cell Types ◽  
Modal Identification ◽  
Large Patch ◽  
Multimodal Data ◽  
Optimization Framework ◽  
Data Prediction ◽  
Cortical Interneurons ◽  
Assignment Analysis

AbstractConsistent identification of neurons and neuronal cell types across different observation modalities is an important problem in neuroscience. Here, we present an optimization framework to learn coordinated representations of multimodal data, and apply it to a large Patch-seq dataset of mouse cortical interneurons. Our approach reveals strong alignment between transcriptomic and electrophysiological profiles of neurons, enables accurate cross-modal data prediction, and identifies cell types that are consistent across modalities.HighlightsCoupled autoencoders for multimodal assignment, Analysis of Patch-seq data consisting of more than 3000 cells

scholarly journals Reconstruction of 1,000 projection neurons reveals new cell types and organization of long-range connectivity in the mouse brain

2019 ◽  
Author(s):  
Johan Winnubst ◽  
Erhan Bas ◽  
Tiago A. Ferreira ◽  
Zhuhao Wu ◽  
Michael N. Economo ◽  
...  
Keyword(s):  
Long Range ◽  
Mouse Brain ◽  
Neuronal Cell ◽  
Cell Types ◽  
Neuronal Morphology ◽  
Projection Neurons ◽  
Axonal Arbor ◽  
Flow Of Information ◽  
Organizational Principles ◽  
The Brain

SummaryNeuronal cell types are the nodes of neural circuits that determine the flow of information within the brain. Neuronal morphology, especially the shape of the axonal arbor, provides an essential descriptor of cell type and reveals how individual neurons route their output across the brain. Despite the importance of morphology, few projection neurons in the mouse brain have been reconstructed in their entirety. Here we present a robust and efficient platform for imaging and reconstructing complete neuronal morphologies, including axonal arbors that span substantial portions of the brain. We used this platform to reconstruct more than 1,000 projection neurons in the motor cortex, thalamus, subiculum, and hypothalamus. Together, the reconstructed neurons comprise more than 75 meters of axonal length and are available in a searchable online database. Axonal shapes revealed previously unknown subtypes of projection neurons and suggest organizational principles of long-range connectivity.

scholarly journals Cell type-specific biotin labeling in vivo resolves regional neuronal proteomic differences in mouse brain

2021 ◽  
Author(s):  
Sruti Rayaprolu ◽  
Sara Bitarafan ◽  
Ranjita Betarbet ◽  
Sydney N Sunna ◽  
Lihong Cheng ◽  
...  
Keyword(s):  
Mouse Brain ◽  
Neurological Diseases ◽  
Neuronal Cell ◽  
Cell Types ◽  
Proteomic Profiling ◽  
Cell Type ◽  
Specific Expression ◽  
Cell Type Specific ◽  
The Brain

Isolation and proteomic profiling of brain cell types, particularly neurons, pose several technical challenges which limit our ability to resolve distinct cellular phenotypes in neurological diseases. Therefore, we generated a novel mouse line that enables cell type-specific expression of a biotin ligase, TurboID, via Cre-lox strategy for in vivo proximity-dependent biotinylation of proteins. Using adenoviral-based and transgenic approaches, we show striking protein biotinylation in neuronal cell bodies and axons throughout the mouse brain. We quantified more than 2,000 neuron-derived proteins following enrichment that mapped to numerous subcellular compartments. Synaptic, transmembrane transporters, ion channel subunits, and disease-relevant druggable targets were among the most significantly enriched proteins. Remarkably, we resolved brain region-specific proteomic profiles of Camk2a neurons with distinct functional molecular signatures and disease associations that may underlie regional neuronal vulnerability. Leveraging the neuronal specificity of this in vivo biotinylation strategy, we used an antibody-based approach to uncover regionally unique patterns of neuron-derived signaling phospho-proteins and cytokines, particularly in the cortex and cerebellum. Our work provides a proteomic framework to investigate cell type-specific mechanisms driving physiological and pathological states of the brain as well as complex tissues beyond the brain.

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