The conduction of electrical signals along myelinated nerve fibers depends on high-density clusters of ion channels at nodes of Ranvier. Demyelinating diseases or injuries disrupt ion channel clusters, block conduction of action potentials in axons, and lead to nervous system dysfunction. Neuron-glia interactions at paranodal junctions flanking nodes contribute to the formation and maintenance of nodes, and participate in bi-directional signaling between neurons and glia.
The specific aims of this project are to determine the molecular mechanisms underlying formation and maintenance of 1) nodes of Ranvier and 2) paranodal junctions. A major impediment to these aims has been the relatively few proteins known to be at these sites. We identified a specialized paranodal cytoskeleton and will determine its role in organizing and maintaining neuroglial interactions and axon stability. We will ablate components of the paranodal cytoskeleton using in vivo electroporation to deliver shRNA plasmids. We speculate that a major cause of axon degeneration as seen in demyelinating diseases is disruption of the axonal cytoskeleton and altered neuroglial interactions. We will identify additional paranodal proteins using biochemical and proteomic methods. To determine the mechanisms underlying node of Ranvier formation, we will identify critical proteins, protein domains, protein-protein interactions, and nodal localization determinants. The proposed experiments are important for many nervous system diseases where neuron-glia interactions are disrupted (e.g., multiple sclerosis, Guillain-Barre syndrome, spinal cord injury). Identification of the mechanisms underlying neuron-glia interactions may contribute to better therapeutic treatments designed to preserve these interactions and their contribution to neuronal health and function.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS044916-11
Application #
8096556
Study Section
Neural Degenerative Disorders and Glial Biology Study Section (NDGB)
Program Officer
Kleitman, Naomi
Project Start
2002-09-30
Project End
2012-07-31
Budget Start
2011-08-01
Budget End
2012-07-31
Support Year
11
Fiscal Year
2011
Total Cost
$329,066
Indirect Cost
Name
Baylor College of Medicine
Department
Neurosciences
Type
Schools of Medicine
DUNS #
051113330
City
Houston
State
TX
Country
United States
Zip Code
77030
Huang, Claire Yu-Mei; Zhang, Chuansheng; Zollinger, Daniel R et al. (2017) An ?II Spectrin-Based Cytoskeleton Protects Large-Diameter Myelinated Axons from Degeneration. J Neurosci 37:11323-11334
Amor, Veronique; Zhang, Chuansheng; Vainshtein, Anna et al. (2017) The paranodal cytoskeleton clusters Na+ channels at nodes of Ranvier. Elife 6:
Huang, Claire Yu-Mei; Zhang, Chuansheng; Ho, Tammy Szu-Yu et al. (2017) ?II Spectrin Forms a Periodic Cytoskeleton at the Axon Initial Segment and Is Required for Nervous System Function. J Neurosci 37:11311-11322
Marin, Miguel A; Ziburkus, Jokubus; Jankowsky, Joanna et al. (2016) Amyloid-? plaques disrupt axon initial segments. Exp Neurol 281:93-8
Zhang, Chuansheng; Rasband, Matthew N (2016) Cytoskeletal control of axon domain assembly and function. Curr Opin Neurobiol 39:116-21
Ko, Kwang Woo; Rasband, Matthew N; Meseguer, Victor et al. (2016) Serotonin modulates spike probability in the axon initial segment through HCN channels. Nat Neurosci 19:826-34
Huang, Yu-Mei; Rasband, Matthew N (2016) Organization of the axon initial segment: Actin like a fence. J Cell Biol 215:9-11
Marin, Miguel A; de Lima, Silmara; Gilbert, Hui-Ya et al. (2016) Reassembly of Excitable Domains after CNS Axon Regeneration. J Neurosci 36:9148-60
Rasband, Matthew N (2016) Glial Contributions to Neural Function and Disease. Mol Cell Proteomics 15:355-61
Normand, Elizabeth A; Rasband, Matthew N (2015) Subcellular patterning: axonal domains with specialized structure and function. Dev Cell 32:459-68

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