Wnt signalling and the differentiation of otic progenitors from human embryonic stem cells

Deafness is a major sensory disorder affecting an enormous number of people worldwide. Loss of the auditory hair cells and their associated spiral ganglion neurons in the cochlea causes the vast majority of hearing loss cases. Therapies currently available are unable to address the root cause of the impairment, and as such are limited in their effectiveness. The field of regenerative medicine is emerging as a viable option for restoring and repairing lost or damaged cells in the inner ear. Human embryonic stem cells have been previously used to generate otic progenitors by employing ligands involved in otic placode induction, FGF 3 and FGF 10. Canonical Wnt signalling is known to play a major role in the expansion of the otic placode. In this work, I have manipulated the canonical Wnt signalling pathway in combination with FGF and explored their effect on otic progenitor differentiation. An initial period of FGF signalling combined with canonical Wnt inhibition was required to promote an ectodermal identity in the differentiating human embryonic stem cells, with a concomitant increase in the expression of otic markers. Following this, a phase of canonical Wnt activation with an attenuated FGF signal further expanded the proportion of otic progenitors, substantially more so than in the standard FGF based protocol. The progenitors derived from this more efficient, developmentally informed protocol also possessed the ability to further differentiate into hair cell-like cells and in particular, auditory neurons. Reporter lines were also generated in order to monitor otic and hair cell differentiation in real time and visualise the effects of manipulating the canonical Wnt signalling pathway with molecular compounds. This work involved the development of an updated in vitro protocol capable of readily and efficiently inducing the differentiation of otic progenitors from human embryonic stem cells. This could be beneficial in the development of potential cell-based therapies for deafness

Surface sulfur content of NGFP nanofiber membrane by energy disperse.

<p>Surface sulfur content of NGFP nanofiber membrane by energy disperse.</p