Dr Dawn Davies

The signalling events that occur during development of the nervous system provide clues to potential techniques for stimulating adult nerve regeneration. The aim of this project is to study the role of the integrin family of cell adhesion molecules in auditory nerve development and to use that information to guide studies on neural attachment and migration on cochlear implant electrodes.

Cochlear implants compensate for hair cell loss by supplying direct electrical stimulation to auditory ganglion cells via electrodes placed in the cochlear duct. However, neurones degenerate following hair cell loss therefore, this technology is only of benefit to those who can receive implants soon after hearing loss, before substantial degeneration.

This problem could be overcome if neurones were encouraged to 'innervate' the implant.

Molecules that are involved in development of inner ear innervation are likely to be important in neural regeneration. Auditory ganglion neurones are born in the otic epithelium. They detach from neighbouring cells, migrate into the mesenchyme and form the ganglion prior to growing dendrites back into the sensory epithelium.

These processes require 'cellular signposts' to direct the cells to the correct location. The signposts are provided by extracellular proteins through interaction with cell surface receptors.

Integrins mediate cell migration and growth through binding to extracellular matrix proteins and are, therefore, likely to be involved in neural development. I am investigating the role of integrins and their ligands in these processes and using this information to inform an investigation into implant coatings aimed at encouraging neural targetting of electrodes and enhancement of implant performance.