The long-term objectives of this research are to elucidate the cellular and molecular mechanisms of development, maintenance and plasticity of the synapse. The present proposal will focus on the involvement of extracellular matrix (ECM) glycoconjugates in these processes at the neuromuscular junction (NMJ) using peanut agglutinin (PNA) as a molecular probe.
The specific aims are: (I). To test the hypothesis that expression of synaptic ECM precedes the nerve terminal outgrowth during synaptic remodeling. (A) Identified NMJs will be observed repeatedly in vivo with video-enhanced microscopy followed by electron microscopy. In addition, whether Schwann cell processes lead the nerve terminal will be studied. (B) The dynamic relationship among nerve terminals, synaptic ECM and acetylcholine receptors during the active growth of sprouting will be examined in vivo. (II). To characterize PNA-binding molecules (PNA-BMs) and test their functions. (A) Affinity chromatography, gel electrophoresis and lectin blotting will be used to isolate and identify the PNA-BMs. (B) Antibodies against PNA-BMs will be produced and immunocytochemistry and immunoblotting performed. (C) The effects of affinity-purified PNA-BMs and functional perturbation with antibodies on neurite outgrowth in vitro will be examined. (D) Antibodies will be applied to perturb the function of PNA-BMs in synapse formation and maintenance in vitro and in vivo. The proposed research would provide novel concepts on the role of the ECM and Schwann cells during synaptic remodeling in living adult animals. The proposal would also characterize new synapse-specific ECM molecules and test the function in formation, plasticity and maintenance of the NMJ. The result may lead to a better understanding of neuromuscular diseases and restoration after trauma. The study may also provide new thinking on learning and memory, which may involve remodeling of synaptic connections in the brain.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS017954-17
Application #
6187587
Study Section
Neurology B Subcommittee 2 (NEUB)
Program Officer
Michel, Mary E
Project Start
1981-12-01
Project End
2002-04-30
Budget Start
2000-05-01
Budget End
2002-04-30
Support Year
17
Fiscal Year
2000
Total Cost
$253,791
Indirect Cost
Name
University of Southern California
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
041544081
City
Los Angeles
State
CA
Country
United States
Zip Code
90089
Feng, Zhihua; Ko, Chien-Ping (2008) Schwann cells promote synaptogenesis at the neuromuscular junction via transforming growth factor-beta1. J Neurosci 28:9599-609
Cao, Guan; Ko, Chien-Ping (2007) Schwann cell-derived factors modulate synaptic activities at developing neuromuscular synapses. J Neurosci 27:6712-22
Feng, Zhihua; Ko, Chien-Ping (2007) Neuronal glia interactions at the vertebrate neuromuscular junction. Curr Opin Pharmacol 7:316-24
Feng, Zhihua; Koirala, Samir; Ko, Chien-Ping (2005) Synapse-glia interactions at the vertebrate neuromuscular junction. Neuroscientist 11:503-13
Corfas, Gabriel; Velardez, Miguel Omar; Ko, Chien-Ping et al. (2004) Mechanisms and roles of axon-Schwann cell interactions. J Neurosci 24:9250-60
Reddy, Linga V; Koirala, Samir; Sugiura, Yoshie et al. (2003) Glial cells maintain synaptic structure and function and promote development of the neuromuscular junction in vivo. Neuron 40:563-80
Peng, H Benjamin; Yang, Jie-Fei; Dai, Zhengshan et al. (2003) Differential effects of neurotrophins and schwann cell-derived signals on neuronal survival/growth and synaptogenesis. J Neurosci 23:5050-60
Koirala, Samir; Reddy, Linga V; Ko, Chien-Ping (2003) Roles of glial cells in the formation, function, and maintenance of the neuromuscular junction. J Neurocytol 32:987-1002
Yang, J F; Cao, G; Koirala, S et al. (2001) Schwann cells express active agrin and enhance aggregation of acetylcholine receptors on muscle fibers. J Neurosci 21:9572-84
Herrera, A A; Qiang, H; Ko, C P (2000) The role of perisynaptic Schwann cells in development of neuromuscular junctions in the frog (Xenopus laevis). J Neurobiol 45:237-54

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