Noncontact Atomic Force Microscopy - Yale School of Engineering ...

P.II-11
Imaging Schwann Cell NGF Receptors using Atomic Force Microscopy
Ryan Williamson and Cheryl Miller
Department of Biomedical Engineering, Saint Louis University, St Louis, MO, USA.
Nerve growth factor (NGF) is a necessary neurotrophic agent that promotes neural
survival and proliferation. Production of NGF by Schwann cells is essential for
successful nerve regeneration. During neural axotomy and the resulting Wallerian
degeneration, Schwann cells increase proliferation while axons and their myelin sheaths
are degraded. The resulting formation, the band of Bungner, is crucial for guidance of
axon sprouts which form during regeneration. Schwann cells in the distal axon will
express the high affinity NGF receptor tyrosine kinase A (TrkA) selectively in the bands
of Bungner as well as the low affinity receptor p75. Using force measurements taken
with a modified atomic force microscopy (AFM) tip to detect binding events, NGF
receptor locations were identified. Using AFM with Schwann cells, we investigated the
expression and conformation of NGF receptors. Receptor location and change during
axon-Schwann cell contact could explain Schwann cell role during regeneration and
possible clinical solutions.
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