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https://www.readbyqxmd.com/read/29907663/reorganization-of-destabilized-nodes-of-ranvier-in-%C3%AE-iv-spectrin-mutants-uncovers-critical-timelines-for-nodal-restoration-and-prevention-of-motor-paresis
#1
Julia Saifetiarova, Qian Shi, Martin Paukert, Masayuki Komada, Manzoor A Bhat
Disorganization of nodes of Ranvier is associated with motor and sensory dysfunctions. Mechanisms that allow nodal recovery during pathological processes remain poorly understood. A highly enriched nodal cytoskeletal protein βIV Spectrin anchors and stabilizes the nodal complex to actin cytoskeleton. Loss of murine βIV Spectrin allows the initial nodal organization, but causes gradual nodal destabilization. Mutations in human βIV SPECTRIN cause auditory neuropathy and impairment in motor coordination and similar phenotypes are caused by nodal disruption due to demyelination...
June 15, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/29882456/absence-of-axoglial-paranodal-junctions-in-a-child-with-cntnap1-mutations-hypomyelination-and-arthrogryposis
#2
Alexander Conant, Julian Curiel, Amy Pizzino, Parisa Sabetrasekh, Jennifer Murphy, Miriam Bloom, Sarah H Evans, Guy Helman, Ryan J Taft, Cas Simons, Matthew T Whitehead, Steven A Moore, Adeline Vanderver
Leukodystrophies and genetic leukoencephalopathies are a heterogeneous group of heritable disorders that affect the glial-axonal unit. As more patients with unsolved leukodystrophies and genetic leukoencephalopathies undergo next generation sequencing, causative mutations in genes leading to central hypomyelination are being identified. Two such individuals presented with arthrogryposis multiplex congenita, congenital hypomyelinating neuropathy, and central hypomyelination with early respiratory failure. Whole exome sequencing identified biallelic mutations in the CNTNAP1 gene: homozygous c...
January 1, 2018: Journal of Child Neurology
https://www.readbyqxmd.com/read/29867996/autoantibodies-against-the-node-of-ranvier-in-seropositive-chronic-inflammatory-demyelinating-polyneuropathy-diagnostic-pathogenic-and-therapeutic-relevance
#3
REVIEW
Atay Vural, Kathrin Doppler, Edgar Meinl
Discovery of disease-associated autoantibodies has transformed the clinical management of a variety of neurological disorders. Detection of autoantibodies aids diagnosis and allows patient stratification resulting in treatment optimization. In the last years, a set of autoantibodies against proteins located at the node of Ranvier has been identified in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). These antibodies target neurofascin, contactin1, or contactin-associated protein 1, and we propose to name CIDP patients with these antibodies collectively as seropositive...
2018: Frontiers in Immunology
https://www.readbyqxmd.com/read/29863101/-guillain-barr%C3%A3-syndrome-following-cytomegalovirus-infection-with-increased-level-of-antibody-against-moesin-a-case-report
#4
Yuji Shiga, Yutaka Shimoe, Masafumi Chigusa, Susumu Kusunoki, Masahiro Mori, Masaru Kuriyama
A 28-year-old man noticed sensory disturbance in the distal parts of his four extremities and muscle weakness of his hands two weeks after cytomegalovirus (CMV) infection. He had splenomegaly, impairment of hepatic function and peripheral neuropathy with decreased tendon reflexes. Protein-cell dissociation was observed in the cerebrospinal fluid, and the nerve conduction study (NCS) showed the changes due to demyelination. Intravenous immunoglobulin therapy was performed for 5 days after the diagnosis of Guillain-Barré syndrome...
June 1, 2018: Rinshō Shinkeigaku, Clinical Neurology
https://www.readbyqxmd.com/read/29861105/%C3%AE-iv-spectrinopathies-cause-profound-intellectual-disability-congenital-hypotonia-and-motor-axonal-neuropathy
#5
Chih-Chuan Wang, Xilma R Ortiz-González, Sabrina W Yum, Sara M Gill, Amy White, Erin Kelter, Laurie H Seaver, Sansan Lee, Graham Wiley, Patrick M Gaffney, Klaas J Wierenga, Matthew N Rasband
βIV spectrin links ankyrinG (AnkG) and clustered ion channels at axon initial segments (AISs) and nodes of Ranvier to the axonal cytoskeleton. Here, we report bi-allelic pathogenic SPTBN4 variants (three homozygous and two compound heterozygous) that cause a severe neurological syndrome that includes congenital hypotonia, intellectual disability, and motor axonal and auditory neuropathy. We introduced these variants into βIV spectrin, expressed these in neurons, and found that 5/7 were loss-of-function variants disrupting AIS localization or abolishing phosphoinositide binding...
June 7, 2018: American Journal of Human Genetics
https://www.readbyqxmd.com/read/29772247/internode-length-is-reduced-during-myelination-and-remyelination-by-neurofilament-medium-phosphorylation-in-motor-axons
#6
Eric Villalón, Devin M Barry, Nathan Byers, Katie Frizzi, Maria R Jones, Dan S Landayan, Jeffrey M Dale, Natalie L Downer, Nigel A Calcutt, Michael L Garcia
The distance between nodes of Ranvier, referred to as internode length, positively correlates with axon diameter, and is optimized during development to ensure maximal neuronal conduction velocity. Following myelin loss, internode length is reestablished through remyelination. However, remyelination results in short internode lengths and reduced conduction rates. We analyzed the potential role of neurofilament phosphorylation in regulating internode length during remyelination and myelination. Following ethidium bromide induced demyelination, levels of neurofilament medium (NF-M) and heavy (NF-H) phosphorylation were unaffected...
May 14, 2018: Experimental Neurology
https://www.readbyqxmd.com/read/29765060/iron-specific-signal-separation-from-within-heavy-metal-stained-biological-samples-using-x-ray-microtomography-with-polychromatic-source-and-energy-integrating-detectors
#7
Tsvi Katchalski, Tom Case, Keun-Young Kim, Ranjan Ramachandra, Eric A Bushong, Thomas J Deerinck, Matthias G Haberl, Mason R Mackey, Steven Peltier, Guillaume A Castillon, Nobuko Fujikawa, Albert R Lawrence, Mark H Ellisman
Biological samples are frequently stained with heavy metals in preparation for examining the macro, micro and ultra-structure using X-ray microtomography and electron microscopy. A single X-ray microtomography scan reveals detailed 3D structure based on staining density, yet it lacks both material composition and functional information. Using a commercially available polychromatic X-ray source, energy integrating detectors and a two-scan configuration labelled by their energy- "High" and "Low", we demonstrate how a specific element, here shown with iron, can be detected from a mixture with other heavy metals...
May 15, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29747821/gangliosides-in-axon-stability-and-regeneration
#8
Pablo H H Lopez, Bárbara Beatriz Báez
Gangliosides are a family of sialic acid-containing glycosphingolipids highly expressed in the nervous system of vertebrates. Over the last 25years, research has unmasked several of their neurobiological functions but the role of gangliosides in the nervous system remains not fully elucidated. Genetic disruption of genes for key enzymes involved in ganglioside biosynthesis led to the discovery of their diverse functions and highlighted the exquisite structural specificity required in this processes. In the nervous system, gangliosides regulate axonal caliber and organize ion channels at the nodes of Ranvier, a critical step to ensure fast conduction velocity of myelinated fibers...
2018: Progress in Molecular Biology and Translational Science
https://www.readbyqxmd.com/read/29741724/myelin-modifications-after-chronic-sleep-loss-in-adolescent-mice
#9
Michele Bellesi, John Douglas Haswell, Luisa de Vivo, William Marshall, Patrick H Roseboom, Giulio Tononi, Chiara Cirelli
Study Objectives: Previous studies found that sleep loss can suppress the expression of genes implicated in myelination and can have adverse effects on oligodendrocyte precursor cells. On the other hand, sleep may favor myelination by promoting the expression of genes involved in its formation and maintenance. Albeit limited, these results suggest that sleep loss can have detrimental effects on the formation and maintenance of myelin. Methods: Here, we tested this hypothesis by evaluating ultrastructural modifications of myelin in two brain regions (corpus callosum and lateral olfactory tract) of mice exposed to different periods of sleep loss, from a few hours of sleep deprivation to ~5 days of chronic sleep restriction...
May 1, 2018: Sleep
https://www.readbyqxmd.com/read/29730177/ankyrins-roles-in-synaptic-biology-and-pathology
#10
REVIEW
Katharine R Smith, Peter Penzes
Ankyrins are broadly expressed adaptors that organize diverse membrane proteins into specialized domains and link them to the sub-membranous cytoskeleton. In neurons, ankyrins are known to have essential roles in organizing the axon initial segment and nodes of Ranvier. However, recent studies have revealed novel functions for ankyrins at synapses, where they organize and stabilize neurotransmitter receptors, modulate dendritic spine morphology and control adhesion to the presynaptic site. Ankyrin genes have also been highly associated with a range of neurodevelopmental and psychiatric diseases, including bipolar disorder, schizophrenia and autism, which all demonstrate overlap in their genetics, mechanisms and phenotypes...
May 3, 2018: Molecular and Cellular Neurosciences
https://www.readbyqxmd.com/read/29729246/oligodendrocyte-specific-loss-of-cdk5-disrupts-the-architecture-of-nodes-of-ranvier-as-well-as-learning-and-memory
#11
Fucheng Luo, Jessie Zhang, Kathryn Burke, Rita R Romito-DiGiacomo, Robert H Miller, Yan Yang
Myelination of the central nervous system is important for normal motor and sensory neuronal function and recent studies also link it to efficient learning and memory. Cyclin-dependent kinase 5 (Cdk5) is required for normal oligodendrocyte development, myelination and myelin repair. Here we show that conditional deletion of Cdk5 by targeting with CNP (CNP;Cdk5 CKO) results in hypomyelination and disruption of the structural integrity of Nodes of Ranvier. In addition, CNP;Cdk5 CKO mice exhibited a severe impairment of learning and memory compared to controls that may reflect perturbed neuron-glial interactions...
May 2, 2018: Experimental Neurology
https://www.readbyqxmd.com/read/29720552/r-ras1-and-r-ras2-are-essential-for-oligodendrocyte-differentiation-and-survival-for-correct-myelination-in-the-central-nervous-system
#12
Miriam Sanz-Rodriguez, Agnès Gruart, Juan Escudero-Ramirez, Fernando de Castro, José María Delgado-García, Francisco Wandosell, Beatriz Cubelos
Rapid and effective neural transmission of information requires correct axonal myelination. Modifications in myelination alter axonal capacity to transmit electric impulses and enable pathological conditions. In the central nervous system (CNS), oligodendrocytes (OLs) myelinate axons, a complex process involving various cellular interactions. However, we know little about the mechanisms that orchestrate correct myelination. Here, we demonstrate that OLs express R-Ras1 and R-Ras2. Using female and male mutant mice to delete these proteins, we find that activation of the PI3K/Akt and Erk1/2-MAPK pathways is weaker in mice lacking one or both of these GTPases, suggesting that both proteins coordinate the activity these two pathways...
May 2, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/29684511/the-effect-of-oxysterols-on-nerve-impulses
#13
REVIEW
Maryem Bezine, Amira Namsi, Randa Sghaier, Rym Ben Khalifa, Haithem Hamdouni, Fatiha Brahmi, Iham Badreddine, Wafa Mihoubi, Thomas Nury, Anne Vejux, Amira Zarrouk, Jérôme de Sèze, Thibault Moreau, Boubker Nasser, Gérard Lizard
The propagation of nerve impulses in myelinated nerve fibers depends on a number of factors involving the myelin and neural axons. In several neurodegenerative diseases, nerve impulses can be affected by the structural and biochemical characteristics of the myelin sheath and the activity of ion channels located in the nodes of Ranvier. Though it is generally accepted that lipid disorders are involved in the development of neurodegenerative diseases, little is known about their impact on nerve impulses. Cholesterol oxide derivatives (also called oxysterols), which are either formed enzymatically or as a result of cholesterol auto-oxidation or both, are often found in abnormal levels in the brain and body fluids of patients with neurodegenerative diseases...
April 21, 2018: Biochimie
https://www.readbyqxmd.com/read/29673258/methylglyoxal-disrupts-paranodal-axoglial-junctions-via-calpain-activation
#14
Ryan B Griggs, Leonid M Yermakov, Domenica E Drouet, Duc V M Nguyen, Keiichiro Susuki
Nodes of Ranvier and associated paranodal and juxtaparanodal domains along myelinated axons are essential for normal function of the peripheral and central nervous systems. Disruption of these domains as well as increases in the reactive carbonyl species methylglyoxal are implicated as a pathophysiology common to a wide variety of neurological diseases. Here, using an ex vivo nerve exposure model, we show that increasing methylglyoxal produces paranodal disruption, evidenced by disorganized immunostaining of axoglial cell-adhesion proteins, in both sciatic and optic nerves from wild-type mice...
January 2018: ASN Neuro
https://www.readbyqxmd.com/read/29664415/model-based-optimal-multipolar-stimulation-without-a-priori-knowledge-of-nerve-structure-application-to-vagus-nerve-stimulation
#15
Mélissa Dali, Olivier Rossel, David Andreu, Laure Laporte, Alfredo Hernández, Jérémy Laforet, Eloi Marijon, Albert Hagège, Maureen Clerc, Christine Henry, David Guiraud
OBJECTIVE: Multipolar cuff electrode can selectively stimulate areas of peripheral nerves and therefore enable to control independent functions. However, the branching and fascicularization are known for a limited set of nerves and the specific organization remains subject-dependent. This paper presents general modeling and optimization methods in the context of multipolar stimulation using a cuff electrode without a priori knowledge of the nerve structure. Vagus nerve stimulation experiments based on the optimization results were then investigated...
April 17, 2018: Journal of Neural Engineering
https://www.readbyqxmd.com/read/29615864/molecular-neuropathology-of-astrocytes-and-oligodendrocytes-in-alcohol-use-disorders
#16
REVIEW
José J Miguel-Hidalgo
Postmortem studies reveal structural and molecular alterations of astrocytes and oligodendrocytes in both the gray and white matter (GM and WM) of the prefrontal cortex (PFC) in human subjects with chronic alcohol abuse or dependence. These glial cellular changes appear to parallel and may largely explain structural and functional alterations detected using neuroimaging techniques in subjects with alcohol use disorders (AUDs). Moreover, due to the crucial roles of astrocytes and oligodendrocytes in neurotransmission and signal conduction, these cells are very likely major players in the molecular mechanisms underpinning alcoholism-related connectivity disturbances between the PFC and relevant interconnecting brain regions...
2018: Frontiers in Molecular Neuroscience
https://www.readbyqxmd.com/read/29525575/signal-propagation-along-the-axon
#17
REVIEW
Sylvain Rama, Mickaël Zbili, Dominique Debanne
Axons link distant brain regions and are usually considered as simple transmission cables in which reliable propagation occurs once an action potential has been generated. Safe propagation of action potentials relies on specific ion channel expression at strategic points of the axon such as nodes of Ranvier or axonal branch points. However, while action potentials are generally considered as the quantum of neuronal information, their signaling is not entirely digital. In fact, both their shape and their conduction speed have been shown to be modulated by activity, leading to regulations of synaptic latency and synaptic strength...
March 8, 2018: Current Opinion in Neurobiology
https://www.readbyqxmd.com/read/29497094/conditional-knockout-of-na-v-1-6-in-adult-mice-ameliorates-neuropathic-pain
#18
Lubin Chen, Jianying Huang, Peng Zhao, Anna-Karin Persson, Fadia B Dib-Hajj, Xiaoyang Cheng, Andrew Tan, Stephen G Waxman, Sulayman D Dib-Hajj
Voltage-gated sodium channels NaV 1.7, NaV 1.8 and NaV 1.9 have been the focus for pain studies because their mutations are associated with human pain disorders, but the role of NaV 1.6 in pain is less understood. In this study, we selectively knocked out NaV 1.6 in dorsal root ganglion (DRG) neurons, using NaV 1.8-Cre directed or adeno-associated virus (AAV)-Cre mediated approaches, and examined the specific contribution of NaV 1.6 to the tetrodotoxin-sensitive (TTX-S) current in these neurons and its role in neuropathic pain...
March 1, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29467340/saltatory-conduction-as-an-electrostatic-compressional-wave-in-the-axoplasm
#19
Tetsuya Akaishi
Saltatory conduction is an essential phenomenon to facilitate the fast conduction in myelinated nerves. The conventional conductive models assumed electric circuits with local current along the axonal membrane to explain the nerve conduction in unmyelinated nerves. However, whether such models with local current can be also applied to the saltatory conduction in myelinated nerves is unknown. In this report, I propose a new model of saltatory conduction by focusing on the behavior of electric charges in the axoplasm, not limited to the membrane...
February 2018: Tohoku Journal of Experimental Medicine
https://www.readbyqxmd.com/read/29444299/early-nodal-and-paranodal-disruption-in-autoimmune-optic-neuritis
#20
Aleksandar Stojic, Jovana Bojcevski, Sarah K Williams, Ricarda Diem, Richard Fairless
Disturbances in the nodes of Ranvier are an early phenomenon in many CNS disorders, including the autoimmune demyelinating disease multiple sclerosis (MS). Using an animal model of optic neuritis, a common early symptom of MS, we have investigated nodal and paranodal compartments in the optic nerve during disease progression. Both nodes and paranodes, as identified by immunohistochemistry against sodium channels (Nav) and Caspr, respectively, were observed to increase in length during the late induction phase of the disease, prior to onset of the demyelination and immune cell infiltration characteristic of optic neuritis...
May 1, 2018: Journal of Neuropathology and Experimental Neurology
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