The acquisition of mature neuronal structure and connectivity depend on synaptic activity during a brief period in early postnatal life. What molecular determinants endow neonatal but not adult neurons with the susceptibility to such developmental activity-dependent plasticity? One determinant appears to be the glutamate receptor subunit GluR1. Neonatal motor neurons are known to express GluR1 abundantly while adults are largely devoid of GluR1. We found expressing GluR1 in motor neurons outside the critical period (using viral vectors) leads to dramatic remodeling of dendritic architecture. To determine if the expression of GluR1 in neonatal motor neurons is important for the normal elaboration of dendrites, we will study mice with a null mutation in GluR1 (specific aim 1). The electrophysiological properties of glutamate receptors containing GluR1 that foster dendrite remodeling will be explored in specific aim 2. This will be accomplished with mutant forms of GluR1 and for comparison, analogous mutants in another subunit GluR2. In addition to the glutamate receptor phenotype of motor neurons, another factor that appears to control dendritic growth during the critical period is nitric oxide (NO). We found that the dendritic tree of developing motor neurons in nNOS knock-out animals is smaller and less branched than wildtype animals.
In specific aim 3, we will express nNOS in the spinal cord (using viral vectors) to more directly implicate NO signaling in dendritogenesis. The similar effects of GluR1 and NO on dendrites suggest a common molecular mechanism may be involved. NO is known to stimulate calcium/calmodulin kinase II (CamKII) and GluR1 is phosphorylated by CamKII. To begin to study a possible link between NO and GluR1 in the developing spinal cord, we will examine the development of dendrites in the CamKII knock-out animals (specific aim 4). If the normal elaboration of the dendritic tree is perturbed, the stage will be set for ordering the molecules we have identified in a pathway that begins with synaptic activity and leads to dendritic growth. Activity-dependent development solves the task of establishing precise connections and application of this form of plasticity may have therapeutic potential for the remodeling brain about insults. These proposed studies aim to uncover the molecular mechanisms subserving the activity-dependent acquisition of mature neuronal phenotype.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS029837-08
Application #
6203926
Study Section
Special Emphasis Panel (ZRG1-MDCN-7 (01))
Program Officer
Nichols, Paul L
Project Start
1993-02-01
Project End
2004-08-31
Budget Start
2000-09-20
Budget End
2001-08-31
Support Year
8
Fiscal Year
2000
Total Cost
$404,305
Indirect Cost
Name
Yale University
Department
Neurology
Type
Schools of Medicine
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520
Zhang, L; Hsu, F-C; Mojsilovic-Petrovic, J et al. (2015) Structure-function analysis of SAP97, a modular scaffolding protein that drives dendrite growth. Mol Cell Neurosci 65:31-44
Kalb, Robert G; Zhou, Weiguo; Zhang, Lei (2013) The molecular basis of experience-dependent motor system development. Adv Exp Med Biol 782:23-38
Jeong, Goo-Bo; Mojsilovic-Petrovic, Jelena; Boccitto, Marco et al. (2011) Signaling events in axons and/or dendrites render motor neurons vulnerable to mutant superoxide dismutase toxicity. J Neurosci 31:295-9
Zhou, Weiguo; Zhang, Lei; Guoxiang, Xiong et al. (2008) GluR1 controls dendrite growth through its binding partner, SAP97. J Neurosci 28:10220-33
Zhang, Lei; Schessl, Joachim; Werner, Markus et al. (2008) Role of GluR1 in activity-dependent motor system development. J Neurosci 28:9953-68
Xiong, Guoxiang; Mojsilovic-Petrovic, Jelena; Perez, Cristian A et al. (2007) Embryonic motor neuron dendrite growth is stunted by inhibition of nitric oxide-dependent activation of soluble guanylyl cyclase and protein kinase G. Eur J Neurosci 25:1987-97
Kalb, Robert; Solomon, David (2007) Space exploration, Mars, and the nervous system. Arch Neurol 64:485-90
Mojsilovic-Petrovic, Jelena; Jeong, Goo-Bo; Crocker, Amanda et al. (2006) Protecting motor neurons from toxic insult by antagonism of adenosine A2a and Trk receptors. J Neurosci 26:9250-63
Jeong, Goo-Bo; Werner, Markus; Gazula, Valeswara-Rao et al. (2006) Bi-directional control of motor neuron dendrite remodeling by the calcium permeability of AMPA receptors. Mol Cell Neurosci 32:299-314
David, Samuel; Stegenga, Susan L; Hu, Peter et al. (2005) Expression of serum- and glucocorticoid-inducible kinase is regulated in an experience-dependent manner and can cause dendrite growth. J Neurosci 25:7048-53

Showing the most recent 10 out of 35 publications