Neuronal growth cones respond to laser-induced axonal damage |
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| Authors: | Tao Wu Samarendra Mohanty Veronica Gomez-Godinez Linda Z. Shi Lih-Huei Liaw Jill Miotke Ronald L. Meyer Michael W. Berns |
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| Affiliation: | 1.Beckman Laser Institute and Medical Clinic, University of California, Irvine, CA 92617, USA;2.Department of Developmental and Cell Biology, University of California, Irvine, CA 92617, USA;3.Department of Biomedical Engineering, University of California, Irvine, CA 92617, USA;4.Department of Bioengineering, University of California, San Diego, CA 92093, USA |
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| Abstract: | Although it is well known that damage to neurons results in release of substances that inhibit axonal growth, release of chemical signals from damaged axons that attract axon growth cones has not been observed. In this study, a 532 nm 12 ns laser was focused to a diffraction-limited spot to produce site-specific damage to single goldfish axons in vitro. The axons underwent a localized decrease in thickness (‘thinning’) within seconds. Analysis by fluorescence and transmission electron microscopy indicated that there was no gross rupture of the cell membrane. Mitochondrial transport along the axonal cytoskeleton immediately stopped at the damage site, but recovered over several minutes. Within seconds of damage nearby growth cones extended filopodia towards the injury and were often observed to contact the damaged site. Turning of the growth cone towards the injured axon also was observed. Repair of the laser-induced damage was evidenced by recovery of the axon thickness as well as restoration of mitochondrial movement. We describe a new process of growth cone response to damaged axons. This has been possible through the interface of optics (laser subcellular surgery), fluorescence and electron microscopy, and a goldfish retinal ganglion cell culture model. |
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| Keywords: | laser ablation growth cone axon axonal injury repair guidance cue |
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