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Axon Stretch Growth: The Mechanotransduction of Neuronal Growth
Published on: August 10, 2011
Neuronal growth cone collapse triggers lateral extensions along trailing axons
R W Davenport1, E Thies, M L Cohen
1Laboratory of Developmental Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480, USA. RD127@umail.umd.edu
Nature Neuroscience
|April 9, 1999
Summary
Axon guidance involves growth cone interactions with cues. Repellent cues cause growth cone retraction and lateral extensions from trailing axons, revealing new guidance mechanisms.
Area of Science:
- Neuroscience
- Cell Biology
- Developmental Biology
Background:
- Axonal outgrowth is primarily understood through growth cone interactions with guidance cues and fasciculation.
- The precise mechanisms governing axon guidance, especially in response to repellent cues, require further elucidation.
Purpose of the Study:
- To investigate the behavioral responses of cultured retinal ganglion cell (RGC) axons and their growth cones when encountering repellent guidance cues.
- To explore the role of lateral extensions in axon guidance and fasciculation dynamics.
Main Methods:
- Utilized cultured retinal ganglion cells to study axonal outgrowth.
- Applied repellent cues, including ephrin-expressing cells and mechanical probing, to observe growth cone and axon behavior.
- Employed transmission electron microscopy for ultrastructural analysis of axonal extensions.
Main Results:
- Contact with repellent cues (ephrins) or mechanical stimulation significantly increased the likelihood of growth cone retraction.
- Observed extensive lateral filopodia and lamellipodia extension hundreds of microns behind the retracting growth cone.
- Transmission electron microscopy revealed that these lateral extensions originated from both pioneer axons and growth cones of defasciculating trailing axons.
Conclusions:
- Repellent cues can induce growth cone retraction and trigger novel guidance behaviors in axons.
- Lateral extensions from axons behind the growth cone play a role in navigating repellent environments and fasciculation dynamics.
- These findings suggest a more complex model of axon guidance involving interactions beyond the immediate growth cone.
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