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Neural Stem Cells and Oligodendrocyte Progenitors in the Central Nervous System
Published in Richard K. Burt, Alberto M. Marmont, Stem Cell Therapy for Autoimmune Disease, 2019
Jennifer A. Jackson, Diana L. Clarke
All cells comprising the CNS are originally derived from the early neuroepithelium that forms as the neural plate along the midline of the developing embryo. As development proceeds, this single layer of pseudostratified epithelium folds to form the neural tube (Fig. 1). The differentiation of the neuroepithelial stem cells into neurons and glia then proceeds in a temporal specific manner that is specific for each region of the developing neural tube.4,5 Generally neurogenesis occurs first, followed by gliogenesis. This patterning of the neural tube is thought to begin at the neural plate stage of development through inductive interactions that create organizing centers at the dorsal and ventral poles.6-8 These specialized neuroepithelial cells generate signals that induce, often in a concentration dependent manner, the expression of patterning genes in adjacent neuroepithelial cells. These patterning genes generally encode homeodomain transcription factors, and their expression patterns divide the cells in the neuroepithelium into different domains along the rostral-caudal and dorso-ventral axes of the neural tube.9,10 These patterning genes are thought to specify neuronal subtype identity and control the duration of specific types of neurogenesis occurring in the brain and spinal cord during each developmental stage.
The Pineal Gland
Published in Nate F. Cardarelli, The Thymus in Health and Senescence, 2019
The human pineal body first appears in the human as a prominent thickening of the ependyma in the posterior part of the roof of the diencephalon at about the 36th gestational day.54 The anlage is initially a single evagination. The anterior base is in the habenular commissure, and the posterior lies in the posteria commissure. Neuroepithelial cells consisting of follicles55,56 proliferate to form the pineal structure. Such follicles are invested by mesoderm. The neuroepithelial cells give rise to the parenchymal cells, and the mesodermal cells form the stroma, which consists of invasculated connective tissue.
Role of Tenascin in Cancer Development
Published in Róza Ádány, Tumor Matrix Biology, 2017
In the optic tectum of 9-day chick embryo, the neuroepithelial cells proliferate and cell migration takes place actively in the ventricular zones. Tenascin protein accumulates not only in the ventricular zone, but also around the radial glial cell bodies, along the radial glial fibers, and at the pia surface, whereas mRNA tenascin is observed only in the ventricular zones.53
Inhibitory Effects of Olea europaea Leaf Extract on Mesenchymal Transition Mechanism in Glioblastoma Cells
Published in Nutrition and Cancer, 2021
Melis Mutlu, Berrin Tunca, Secil Ak Aksoy, Cagla Tekin, Unal Egeli, Gulsah Cecener
Tumor cell migration and invasion of surrounding tissues such as necrosis and vascular proliferation are important characteristics of GB (4). Factors leading to GB invasion are discussed in many studies (5–8). This invasion has been shown to cause cellular cytoskeleton remodeling and decreasing cell and matrix adhesion and various network proteins included in this process. Epithelial–mesenchymal transition (EMT) is a condition in which cells lose their epithelial characteristics and show mesenchymal transition (9). EMT is characterized by cells with high invasion and migration capacity (10). The cellular molecular mechanisms of EMT consist of complex signaling networks. One of the most distinctive features of EMT, is loss of the cell adhesion glycoprotein E-cadherin (11). Although brain tissue is not a classical epithelial cell, during embryonic development, it is thought that epithelial cell differentiation takes similar responsibilities in the development of tumors of the brain, especially in the brain, because the nerve plate consists of undifferentiated neuroepithelial cells (12). The decrease in E-cadherin and increase in Zeb1, Snail, Twist, N-cadherin in GB cells, supports mesenchymal transition (MT) and decreasing the increased levels of expression is predicted to prevent the progression of the tumor and make them susceptible to chemotherapeutics (13). Therefore, the development of novel molecules that provide inhibition of MT inducing factors may helpful in the treatment of GB.
Multimodal Imaging Characteristics of a Rare Co-occurrence of Optic Nerve Head Drusen and Peripapillary Myelinated Retinal Nerve Fibres
Published in Neuro-Ophthalmology, 2021
Dilek Top Karti, Hasan Mahmut Arcagok, Omer Karti
MRNFs are rare congenital anomalies that may be located at the disc, peripapillary area, and/or elsewhere on the retina.9–11 Their prevalence are 0.54% and bilaterality has been reported as 7.7% of cases.10 Although MRNF is usually MRNFs are usually sporadic, although they may be associated with many systemic syndromes such as Down, Turner, Goltz-Gorlin, and GAPO (growth retardation, alopecia, pseudoanodontia, optic atrophy).11 Current investigations have suggested that oligodendrocyte progenitor cells arising from neuroepithelial cells and ectopically located in the retina have been responsible for the pathogenesis. These fan-shaped lesions, which are consistent with the distribution of the RNFL settle into the outermost surface of the retina. They appear as grey-white well-demarcated opaque patches with feathery edges and may obscure the details of the underlying retina and its vascular structures.9–11 Many studies have reported that MRNF are more common in patients with anisometropia, strabismus, and amblyopia.10–12
Reelin promotes oligodendrocyte precursors migration via the Wnt/β-catenin signaling pathway
Published in Neurological Research, 2021
Yaping Liu, Yuanyuan Wang, Wen Yuan, Fuxing Dong, Fei Zhen, Jing Liu, Lihua Yang, Xuebin Qu, Ruiqin Yao
Oligodendrocyte precursors (OPCs) are stem cells with high proliferation and differentiation potential. They are derived from neuroepithelial cells in the ventral side of the neural tube during early embryonic development. With the development of the central nervous system, OPCs gradually migrate, proliferate and differentiate into mature oligodendrocytes (OLs), enveloping neurons to form myelin [1]. Reelin is an extracellular matrix glycoprotein with a total molecular weight of approximately 460 kDa that plays an important role in nervous system development [2,3]. The spatiotemporal regulation of Reelin expression is the foundation of its role in brain development. Cajal-Retzius cells, which are located in the forebrain, secrete high levels of Reelin in the marginal zone during embryonic development [4,5], they also regulate neuron migration and cell layer formation [6], and disappear from the new cortex once neuron migration is complete. Reelin expression is concentrated mainly in GABAergic interneurons and is present at low levels in the cortical and hippocampal cell layers during development [7]. In addition, Reelin may be related to the regulation of synaptic activity and plasticity [8,9]. Reelin exerts its function by binding to apolipoprotein E receptor 2 (ApoER2) and very-low-density lipoprotein receptor (VLDLR) on the surface of target cells [5]. After binding to any of these receptors, Reelin causes Disabled-1 (Dab1) aggregation and phosphorylation, which are essential for the migration and differentiation of OPCs [10,11]. Currently, there are few studies on Reelin and OPCs. Siebert et al. performed gene chip detection at different time points in the development of OPCs, and the results showed that the mRNA expression of Reelin, VLDLR and the intracellular junction protein Dab1 was present [12].