Mechanosensitivity in Axon Growth and Guidance – 11/19/12

Mechanosensitivity in Axon Growth and Guidance – 11/19/12

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Jeffrey Urbach,
Professor, Department of Physics,
Georgetown University.

A mechanistic understanding of the processes that control axon growth and guidance is essential for understanding the development of the nervous system and engineering successful regrowth of severed neurons following spinal cord injury.  The growth cone, a highly motile structure at the tip of a growing axon, integrates information about the local environment and modulates outgrowth and guidance, but little is known about effects of external mechanical cues and internal mechanical forces on growth cone behavior.  We have investigated axon outgrowth and force generation on soft elastic substrates for dorsal root ganglion (DRG) neurons (from the peripheral nervous system) and hippocampal neurons (from the central) to see how the mechanics of the microenvironment affect different populations.  We find that force generation and stiffness-dependent outgrowth are strongly dependent on cell type.  We also observe very different internal dynamics and substrate coupling in the two populations, suggesting that the difference in force generation is due to stronger adhesions and therefore stronger substrate engagement in the peripheral nervous system neurons.   During development, these axons navigate over a stiffer and more heterogeneous environment than those from the central nervous system. It appears that their biomechanical sensitivity is tuned to their mechanical environment, which suggests new strategies for facilitating nervous system repair.

See his website for more information on his research.