Morphology and intrinsic excitability of regenerating sensory and motor neurons grown on a line micropattern

PLoS One. 2014 Oct 20;9(10):e110687. doi: 10.1371/journal.pone.0110687. eCollection 2014.

Abstract

Axonal regeneration is one of the greatest challenges in severe injuries of peripheral nerve. To provide the bridge needed for regeneration, biological or synthetic tubular nerve constructs with aligned architecture have been developed. A key point for improving axonal regeneration is assessing the effects of substrate geometry on neuronal behavior. In the present study, we used an extracellular matrix-micropatterned substrate comprising 3 µm wide lines aimed to physically mimic the in vivo longitudinal axonal growth of mice peripheral sensory and motor neurons. Adult sensory neurons or embryonic motoneurons were seeded and processed for morphological and electrical activity analyses after two days in vitro. We show that micropattern-guided sensory neurons grow one or two axons without secondary branching. Motoneurons polarity was kept on micropattern with a long axon and small dendrites. The micro-patterned substrate maintains the growth promoting effects of conditioning injury and demonstrates, for the first time, that neurite initiation and extension could be differentially regulated by conditioning injury among DRG sensory neuron subpopulations. The micro-patterned substrate impacts the excitability of sensory neurons and promotes the apparition of firing action potentials characteristic for a subclass of mechanosensitive neurons. The line pattern is quite relevant for assessing the regenerative and developmental growth of sensory and motoneurons and offers a unique model for the analysis of the impact of geometry on the expression and the activity of mechanosensitive channels in DRG sensory neurons.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Axons / metabolism
  • Cells, Cultured
  • Dendrites / metabolism
  • Ganglia, Spinal / cytology
  • Ganglia, Spinal / physiology*
  • Mice
  • Mice, Transgenic
  • Motor Neurons / cytology
  • Motor Neurons / metabolism*
  • Nerve Regeneration / physiology*
  • Peripheral Nerves / cytology
  • Peripheral Nerves / physiology*
  • Sensory Receptor Cells / cytology
  • Sensory Receptor Cells / metabolism

Grants and funding

This work was supported by grants from the Institut National de la Santé et de la Recherche Médicale (Inserm), Association Française contre les Myopathies (AFM). The authors are grateful for the financial support obtained from the LABEX NUMEV for the Ph.D fellowship of OB. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.