Dresden 2009 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 17: Poster II

BP 17.5: Poster

Mittwoch, 25. März 2009, 17:15–19:45, P3

Mechanics in Neuronal Development — •Kristian Franze¹, Hanno Svoboda¹, Pouria Moshayedi¹, Andreas Christ¹, James Fawcett¹, Josef Kas², Christine Holt¹, and Jochen Guck¹ — ¹University of Cambridge, UK — ²University of Leipzig, Germany

The neuronal preference for soft substrates and the softness of radial glial cells, along which neurons preferentially grow, strongly point towards a role of mechanics in neuronal guidance. Here we show how neurons detect and avoid stiff substrates and how their mechano-responsiveness is used to guide their axons.

In vitro, neurons continuously probe the mechanical properties of their environment. Growth cones visibly deformed substrates with a compliance commensurate with their own. Externally applied mechanical stress exceeding the threshold of ~300 Pa caused a calcium influx through mechanosensitive ion channels in the growth cone membrane that triggered neurite retraction. Subsequently, neuronal processes re-extended, thereby enabling exploration of alternative directions. To study the physiological consequences of this mechano-responsiveness, Xenopus eye primordia were cultured on polyacrylamide gels of various compliances. If the outgrowing retinal axons grew either on soft or on stiff substrates, they spread over a wide area. In contrast, on substrates of intermediate compliance they fasciculated and grew into one common direction, resembling an optic nerve. Hence, neurons may actively use mechanics as previously unknown guidance cue. This knowledge may ultimately help in finding new implants that promote axonal regeneration in the injured nervous system.