Self-aligned Schwann cell monolayers demonstrate an inherent ability to direct neurite outgrowth

In vivo nerve guidance channel studies have identified Schwann cell (SC) presence as an integral factor in axonal number and extension in an injury site, and in vitro studies have provided evidence that oriented SCs can direct neurite outgrowth. However, traditional methods used to create oriented SC monolayers (e.g. micropatterns/microtopography) potentially introduce secondary guidance cues to the neurons that are difficult to de-couple. Although SCs expanded on uniform laminin-coated coverslips lack a global orientation, the monolayers contain naturally formed regions of locally oriented cells that can be used to investigate SC-mediated neurite guidance. In this work, novel image analysis techniques have been developed to quantitatively assess local neurite orientation with respect to the underlying regional orientation of the Schwann cell monolayer. Results confirm that, in the absence of any secondary guidance cues, a positive correlation exists between neurite outgrowth and regional orientation of the SC monolayer. Thus, SCs alone possess an inherent ability to direct neurite outgrowth, and expansion of the co-culture-based quantitative method described can be used to further deconstruct specific biomolecular mechanisms of neurite guidance.