scholarly journals Drosophila ßHeavy-Spectrin is required in polarized ensheathing glia that form a diffusion-barrier around the neuropil

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nicole Pogodalla ◽  
Holger Kranenburg ◽  
Simone Rey ◽  
Silke Rodrigues ◽  
Albert Cardona ◽  
...  

AbstractIn the central nervous system (CNS), functional tasks are often allocated to distinct compartments. This is also evident in the Drosophila CNS where synapses and dendrites are clustered in distinct neuropil regions. The neuropil is separated from neuronal cell bodies by ensheathing glia, which as we show using dye injection experiments, contribute to the formation of an internal diffusion barrier. We find that ensheathing glia are polarized with a basolateral plasma membrane rich in phosphatidylinositol-(3,4,5)-triphosphate (PIP3) and the Na+/K+-ATPase Nervana2 (Nrv2) that abuts an extracellular matrix formed at neuropil-cortex interface. The apical plasma membrane is facing the neuropil and is rich in phosphatidylinositol-(4,5)-bisphosphate (PIP2) that is supported by a sub-membranous ßHeavy-Spectrin cytoskeleton. ßHeavy-spectrin mutant larvae affect ensheathing glial cell polarity with delocalized PIP2 and Nrv2 and exhibit an abnormal locomotion which is similarly shown by ensheathing glia ablated larvae. Thus, polarized glia compartmentalizes the brain and is essential for proper nervous system function.

2021 ◽  
Author(s):  
Nicole Pogodalla ◽  
Holger Kranenburg ◽  
Simone Rey ◽  
Silke Rodrigues ◽  
Albert Cardona ◽  
...  

In the central nervous system (CNS), functional tasks are often allocated to distinct compartments. This is also evident in the insect CNS where synapses and dendrites are clustered in distinct neuropil regions. The neuropil is separated from neuronal cell bodies by ensheathing glia, which as we show using dye injection experiments forms an internal diffusion barrier. We find that ensheathing glial cells are polarized with a basolateral plasma membrane rich in phosphatidylinositol-(3,4,5)-triphosphate (PIP3) and the Na+/K+-ATPase Nervana2 (Nrv2) that abuts an extracellular matrix formed at neuropil-cortex interface. The apical plasma membrane is facing the neuropil and is rich in phosphatidylinositol-(4,5)-bisphosphate (PIP2) that is supported by a sub-membranous beta-Heavy-Spectrin cytoskeleton. beta-Heavy-spectrin mutant larvae affect ensheathing glial cell polarity with delocalized PIP2 and Nrv2 and exhibit an abnormal locomotion which is similarly shown by ensheathing glia ablated larvae. Thus, polarized glia compartmentalizes the brain and is essential for proper nervous system function.


Author(s):  
Anthony A. Paparo ◽  
Judith A. Murphy

The purpose of this study was to localize the red neuronal pigment in Mytilus edulis and examine its role in the control of lateral ciliary activity in the gill. The visceral ganglia (Vg) in the central nervous system show an over al red pigmentation. Most red pigments examined in squash preps and cryostat sec tions were localized in the neuronal cell bodies and proximal axon regions. Unstained cryostat sections showed highly localized patches of this pigment scattered throughout the cells in the form of dense granular masses about 5-7 um in diameter, with the individual granules ranging from 0.6-1.3 um in diame ter. Tissue stained with Gomori's method for Fe showed bright blue granular masses of about the same size and structure as previously seen in unstained cryostat sections.Thick section microanalysis (Fig.l) confirmed both the localization and presence of Fe in the nerve cell. These nerve cells of the Vg share with other pigmented photosensitive cells the common cytostructural feature of localization of absorbing molecules in intracellular organelles where they are tightly ordered in fine substructures.


Development ◽  
1998 ◽  
Vol 125 (14) ◽  
pp. 2747-2758 ◽  
Author(s):  
A.C. Lekven ◽  
U. Tepass ◽  
M. Keshmeshian ◽  
V. Hartenstein

We examined the structure of the nervous system in Drosophila embryos homozygous for a null mutation in the faint sausage (fas) gene. In the peripheral nervous system (PNS) of fas mutants, neurons fail to delaminate from the ectodermal epithelium; in the central nervous system (CNS), the positions of neuronal cell bodies and glial cells are abnormal and normal axonal pathways do not form. Sequence analysis of fas cDNAs revealed that the fas protein product has characteristics of an extracellular protein and that it is a novel member of the immunoglobulin (Ig) superfamily. In situ hybridization demonstrated that fas transcripts are expressed throughout the embryo but they are in relatively high concentrations in the lateral ectoderm, from which the peripheral nervous system delaminates and in the CNS. Antiserum directed against Fas protein was found to stain neurons but not glia in the CNS. We conclude that fas encodes a protein that, in the developing nervous system, is present on the surface of neurons and is essential for nerve cell migration and the establishment of axonal pathways.


Author(s):  
Sarah A Neely ◽  
Jill M Williamson ◽  
Anna Klingseisen ◽  
Lida Zoupi ◽  
Jason J Early ◽  
...  

Regeneration of myelin (remyelination) in the central nervous system (CNS) has long been thought to be principally mediated by newly generated oligodendrocytes, a premise underpinning therapeutic strategies for demyelinating diseases, including multiple sclerosis (MS). Recent studies have indicated that oligodendrocytes that survive demyelination can also contribute to remyelination, including in MS, but it is unclear how remyelination by surviving oligodendrocytes compares to that of newly generated oligodendrocytes. Here we studied oligodendrocytes in MS, and also imaged remyelination in vivo by surviving and new oligodendrocytes using zebrafish. We define a previously unappreciated pathology in MS, myelination of neuronal cell bodies, which is recapitulated during remyelination by surviving oligodendrocytes in zebrafish. Live imaging also revealed that surviving oligodendrocytes make very few new sheaths, but can support sheath growth along axons. In comparison, newly made oligodendrocytes make abundant new sheaths, properly targeted to axons, and exhibit a much greater capacity for regeneration.


Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 529
Author(s):  
Elena V. Ryabova ◽  
Pavel A. Melentev ◽  
Artem E. Komissarov ◽  
Nina V. Surina ◽  
Ekaterina A. Ivanova ◽  
...  

Glia are crucial for the normal development and functioning of the nervous system in many animals. Insects are widely used for studies of glia genetics and physiology. Drosophila melanogaster surface glia (perineurial and subperineurial) form a blood–brain barrier in the central nervous system and blood–nerve barrier in the peripheral nervous system. Under the subperineurial glia layer, in the cortical region of the central nervous system, cortex glia encapsulate neuronal cell bodies, whilst in the peripheral nervous system, wrapping glia ensheath axons of peripheral nerves. Here, we show that the expression of the evolutionarily conserved swiss cheese gene is important in several types of glia. swiss cheese knockdown in subperineurial glia leads to morphological abnormalities of these cells. We found that the number of subperineurial glia nuclei is reduced under swiss cheese knockdown, possibly due to apoptosis. In addition, the downregulation of swiss cheese in wrapping glia causes a loss of its integrity. We reveal transcriptome changes under swiss cheese knockdown in subperineurial glia and in cortex + wrapping glia and show that the downregulation of swiss cheese in these types of glia provokes reactive oxygen species acceleration. These results are accompanied by a decline in animal mobility measured by the negative geotaxis performance assay.


2015 ◽  
Vol 370 (1672) ◽  
pp. 20140196 ◽  
Author(s):  
Francisco F. De-Miguel ◽  
Carolina Leon-Pinzon ◽  
Paula Noguez ◽  
Bruno Mendez

Serotonin, a modulator of multiple functions in the nervous system, is released predominantly extrasynaptically from neuronal cell bodies, axons and dendrites. This paper describes how serotonin is released from cell bodies of Retzius neurons in the central nervous system (CNS) of the leech, and how it affects neighbouring glia and neurons. The large Retzius neurons contain serotonin packed in electrodense vesicles. Electrical stimulation with 10 impulses at 1 Hz fails to evoke exocytosis from the cell body, but the same number of impulses at 20 Hz promotes exocytosis via a multistep process. Calcium entry into the neuron triggers calcium-induced calcium release, which activates the transport of vesicle clusters to the plasma membrane. Exocytosis occurs there for several minutes. Serotonin that has been released activates autoreceptors that induce an inositol trisphosphate-dependent calcium increase, which produces further exocytosis. This positive feedback loop subsides when the last vesicles in the cluster fuse and calcium returns to basal levels. Serotonin released from the cell body is taken up by glia and released elsewhere in the CNS. Synchronous bursts of neuronal electrical activity appear minutes later and continue for hours. In this way, a brief train of impulses is translated into a long-term modulation in the nervous system.


1991 ◽  
Vol 39 (12) ◽  
pp. 1645-1658 ◽  
Author(s):  
K Maggio ◽  
A Watrin ◽  
E Keicher ◽  
G Nicaise ◽  
M L Hernandez-Nicaise

The localization of Ca(2+)- and Mg(2+)-ATPases was determined in Aplysia central and peripheral nervous system, using an electron microscopic cytochemical method. The enzyme activity appeared localized to the membrane of glial granules (gliagrana), particularly in the peripheral nervous system of the esophagus, and on the plasma membrane of central glial cells adjacent to neuronal cell bodies. No calcium- and/or magnesium-ATPase activity was detectable on the plasma membrane of glial cells surrounding nerve axons in the pleuro-visceral connectives. These findings are discussed along two main lines: (a) the calcium-ATPase of the gliagrana coincides with a high intragranular calcium and/or proton concentration; and (b) the presence of a calcium-ATPase activity at the glio-neuronal interface around the neuronal cell bodies coincides with the use of calcium ions as charge carriers of the action potential, and its absence at the level of the axon with the concurrent functional use of sodium ions.


Author(s):  
Giedre Milinkeviciute ◽  
Karina S. Cramer

The auditory brainstem carries out sound localization functions that require an extraordinary degree of precision. While many of the specializations needed for these functions reside in auditory neurons, additional adaptations are made possible by the functions of glial cells. Astrocytes, once thought to have mainly a supporting role in nervous system function, are now known to participate in synaptic function. In the auditory brainstem, they contribute to development of specialized synapses and to mature synaptic function. Oligodendrocytes play critical roles in regulating timing in sound localization circuitry. Microglia enter the central nervous system early in development, and also have important functions in the auditory system’s response to injury. This chapter highlights the unique functions of these non-neuronal cells in the auditory system.


Endocrinology ◽  
2018 ◽  
Vol 160 (1) ◽  
pp. 156-168 ◽  
Author(s):  
Mariano Martín ◽  
Carlos Pablo Modenutti ◽  
Victoria Peyret ◽  
Romina Celeste Geysels ◽  
Elisabeth Darrouzet ◽  
...  

Abstract The Na+/iodide (I−) symporter (NIS), a glycoprotein expressed at the basolateral plasma membrane of thyroid follicular cells, mediates I− accumulation for thyroid hormonogenesis and radioiodide therapy for differentiated thyroid carcinoma. However, differentiated thyroid tumors often exhibit lower I− transport than normal thyroid tissue (or even undetectable I− transport). Paradoxically, the majority of differentiated thyroid cancers show intracellular NIS expression, suggesting abnormal targeting to the plasma membrane. Therefore, a thorough understanding of the mechanisms that regulate NIS plasma membrane transport would have multiple implications for radioiodide therapy. In this study, we show that the intracellularly facing carboxy-terminus of NIS is required for the transport of the protein to the plasma membrane. Moreover, the carboxy-terminus contains dominant basolateral information. Using internal deletions and site-directed mutagenesis at the carboxy-terminus, we identified a highly conserved monoleucine-based sorting motif that determines NIS basolateral expression. Furthermore, in clathrin adaptor protein (AP)-1B–deficient cells, NIS sorting to the basolateral plasma membrane is compromised, causing the protein to also be expressed at the apical plasma membrane. Computer simulations suggest that the AP-1B subunit σ1 recognizes the monoleucine-based sorting motif in NIS carboxy-terminus. Although the mechanisms by which NIS is intracellularly retained in thyroid cancer remain elusive, our findings may open up avenues for identifying molecular targets that can be used to treat radioiodide-refractory thyroid tumors that express NIS intracellularly.


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