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BP: Fachverband Biologische Physik
BP 23: Cell Motility and Migration (in vitro and in vivo)
BP 23.3: Talk
Thursday, March 29, 2007, 14:45–15:00, H43
Glial Cell Stiffness as Guidance Cue for Neurons — •Kristian Franze1,2, Timo Betz1, Yunbi Lu1,2, Johannes Bayer3, Melike Lakadamyali3, Paul Janmey4, and Josef Käs1 — 1Soft Matter Physics, Universität Leipzig — 2Paul-Flechsig-Institute of Brain Research, Universität Leipzig — 3CNLD, University of Texas, Austin, USA — 4Inst. Medicin & Engineering, University of Pennsylvania, Philadelphia, USA
Neuronal migration is a fundamental event during development. Neurons travel from the ventricular zone, the place of their origin, to the cortical plate, bridging distances that can be a multiple of their length. Radial glial cells, which are cells that connect the ventricular zone with the opposing cortical surface with two long, radial processes, are known to guide neuronal migration. Neurons attach to these cells and precisely follow their processes, even if they are significantly bent. No biochemical guidance cues have been identified for this behavior and simple diffusive gradients cannot explain how neurons follow the bent glial shape. We found that in vitro neurons actively probe their mechanical environment. They retracted their processes and reextended them in a random direction when mechanical stresses exceeding ~300 Pa opposed their leading edge. This threshold corresponds to the maximum substrate stiffness that neurons could visibly deform. Interestingly, radial glial cells were softer than 300 Pa, suggesting that their mechanical properties may facilitate neuronal radial migration in the developing brain. This is in sharp contrast to the current opinion that neuronal guidance is solely based on biochemical signaling.