Stem cell therapy for hearing loss: Math1 overexpression in VOT-E36 cells

作者：Liu JJ; Shin JH; Hyrc TL; Liu S; Lei DB; Holley IC; Bao JX^*

来源：Otology & Neurotology, 2006, 27(3): 414-421.

DOI：10.1097/00129492-200604000-00020

• hair cell
• hearing loss
• Math1
• stem cell
• VOT-E36

Hypothesis: VOT-E36 cells acquire rnechanosensitivity after mammalian atonal homolog 1 (Math1) overexpression.
Background: VOT-E36 cells are derived from a population of epithelial cells in the ventral region of the otocyst at embryonic Day 10.5, before hair cell differentiation. These cells express a number of specific molecular markers for hair cells under both proliferation and differentiation states. Overexpression of Math1 can convert nonsensory epithelial cells into hair cells in the cochlea. Based on this information, we tested whether VOT-E36 cells can be converted into hair cells by Math1 overexpression,
Methods: Using reverse transcriptase-polymerase chain reaction-based analysis, we first compared the expression patterns of various molecular markers for hair cell development in VOT-E36 cells between proliferation and differentiation states, and also before and after overexpression of Math1. Subsequently, with a standard calcium imaging method, we examined whether VOT-E36 cells overexpressing Math1 could detect mechanical vibrations and activate spiral ganglion neurons in a coculture model. In addition, using confocal and scanning electron microscopes, we examined morphologic changes of VOT-E36 cells after Math1 overexpression.
Results: Consistent with previous reports, this study has shown that VOT-E36 cells express a number of specific molecular markers for hair cells in both proliferation and differentiation states. Under appropriate culture conditions, Math1 is transiently expressed in this cell line during conditional differentiation. In VOT-E36 cells overexpressing Math1, the normal expression pattern of certain molecular markers for mature hair cells is partially restored. Interestingly, after coculture with spiral ganglion neurons, VOT-E36 cells overexpressing Math1 are able to respond to mechanical vibrations and activate spiral ganglion neurons. Possible molecular mechanisms underlying this novel finding have been explored.
Conclusion: Math1 overexpression can partially restore presumably downstrearn signaling cascades for normal hair cell differentiation in VOT-E36 cells, which are able to detect mechanical vibrations after being cocultured with spiral ganglion neurons.

• 出版日期2006-4