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Activity-induced rapid synaptic maturation mediated by presynaptic cdc42 signaling
Wanhua Shen1, Bei Wu, Zhijun Zhang
1Institute of Neuroscience and Key Laboratory of Neurobiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
Neuron
|May 6, 2006
Summary
Neuronal activity rapidly enhances presynaptic glutamate release, converting nonfunctional contacts into functional synapses. This process involves brain-derived neurotrophic factor (BDNF) and Cdc42 signaling pathways, crucial for synaptic maturation.
Area of Science:
- Neuroscience
- Cell Biology
- Synaptic Plasticity
Background:
- Synaptogenesis requires the maturation of presynaptic machinery for neurotransmitter secretion.
- Early neuronal contacts are initially nonfunctional and require maturation to become active synapses.
Purpose of the Study:
- To investigate the rapid mechanisms underlying presynaptic maturation induced by neuronal activity.
- To identify key signaling pathways and molecular players involved in activity-dependent synapse formation.
Main Methods:
- Utilized cultured hippocampal neurons to study synaptogenesis.
- Applied electrical stimulation (action potentials) to induce synaptic activity.
- Quantified presynaptic glutamate release using FM4-64 dye imaging.
- Investigated the roles of brain-derived neurotrophic factor (BDNF), Cdc42 signaling, and actin polymerization.
Main Results:
- A brief train of action potentials rapidly enhanced presynaptic glutamate release and converted nonfunctional contacts into functional synapses.
- This maturation process was dependent on presynaptic BDNF and Cdc42 signaling, as well as actin polymerization.
- Activation of Cdc42 by BDNF or bradykinin mimicked the effects of electrical activity.
- Activity-induced actin polymerization at axon boutons was dependent on BDNF and Cdc42 signaling.
Conclusions:
- Neuronal activity rapidly promotes presynaptic maturation by enhancing glutamate release.
- The Cdc42 signaling pathway, activated by BDNF, plays a critical role in activity-induced presynaptic maturation.
- Actin polymerization is a key downstream event in this process, linking neuronal activity to synapse development.