Regulation of neuromuscular synapse development by glial cell line-derived neurotrophic factor and neurturin.
Glial cell line-derived neurotrophic factor (GDNF) is known for its potent effect on neuronal survival, but its role in the development and function of synapses is not well studied. Using Xenopus nerve-muscle co-cultures, we show that GDNF and its family member neurturin (NRTN) facilitate the development of the neuromuscular junction (NMJ). Long-term application of GDNF significantly increased the total length of neurites in the motoneurons. GDNF also caused an increase in the number and the size of synaptic vesicle clustering, as demonstrated by synaptobrevin-GFP fluorescent imaging, and FM dye staining. Electrophysiological experiments revealed two effects of GDNF on synaptic transmission at NMJ. First, GDNF markedly increased the frequency of spontaneous transmission and decreased the variability of evoked transmission, suggesting an enhancement of transmitter secretion. Second, GDNF elicited a small increase in the quantal size, without affecting the average rise and decay times of synaptic currents. Imaging analysis showed that the size of acetylcholine receptor clusters at synapses increased in muscle cells overexpressing GDNF. Neurturin had very similar effects as GDNF. These results suggest that GDNF and NRTN are new neuromodulators that regulate the development of the neuromuscular synapse through both pre- and postsynaptic mechanisms.
Wang
Chang-Yu
CY
Unit on Synapse Development and Plasticity, NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA.
Yang
Feng
F
He
Xiang-Ping
XP
Je
Hyun-Soo
HS
Zhou
Jian-Zheng
JZ
Eckermann
Kary
K
Kawamura
David
D
Feng
Linyin
L
Shen
Liya
L
Lu
Bai
B
D000818:Animals; D002478:Cells, Cultured; D018920:Coculture Techniques; D018076:DNA, Complementary / Q000378:metabolism; D004594:Electrophysiology; D051100:Glial Cell Line-Derived Neurotrophic Factor; D049452:Green Fluorescent Proteins; D006801:Humans; D007150:Immunohistochemistry; D008164:Luminescent Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009046:Motor Neurons / Q000378:metabolism*; D009132:Muscles / Q000166:cytology* / Q000294:innervation*; D009414:Nerve Growth Factors / Q000737:chemistry* / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009469:Neuromuscular Junction / Q000196:embryology*; D009474:Neurons / Q000166:cytology* / Q000187:drug effects; D051101:Neurturin; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D050683:R-SNARE Proteins; D011950:Receptors, Cholinergic / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013569:Synapses / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors; D014158:Transcription, Genetic; D014981:Xenopus
D018076:DNA, Complementary; C495039:GDNF protein, human; D051100:Glial Cell Line-Derived Neurotrophic Factor; D008164:Luminescent Proteins; D008565:Membrane Proteins; C495053:NRTN protein, human; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D051101:Neurturin; D050683:R-SNARE Proteins; D011950:Receptors, Cholinergic; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins