Cells that aid hearing created in lab

Scientists have successfully developed a way to coax embryonic stem cells to become the inner-ear hair cells which are responsible for hearing and sense of balance.
This is an important step for the future production of large numbers of these cells for use in cell transplantation therapies or large-scale drug screens, researchers said.
Sensory hair cells located in the inner ear are vital for our sense of hearing and balance. As these cells are unable to regenerate, millions of people worldwide have permanent hearing and balance impairments.
Previous studies had already reported the successful generation of hair cells in the lab, but the protocols used were complex and inefficient.

To overcome these problems, the team led by Domingos Henrique from the Molecular Medicine Institute in Lisbon, Portugal decided to follow a different strategy.
"We explored the extensive knowledge on the various regulatory proteins that control hair cell development in the embryo to design an effective combination of three transcription factors able to induce the formation of these cells," said Henrique and Aida Costa, the graduate student involved in the work.

The team applied this simpler approach to mouse embryonic stem cells in a dish, which have the potential to become any cell type.
They were able to convert these cells into hair cells, more successfully and with higher efficiencies than previously reported.

Excitingly, when the team added the three players to cells in the ear of a developing chick embryo they were also able to induce the formation of many new hair cells, including in areas where they do not form normally, suggesting that a similar strategy might work in vivo.
"Hair cells get their name from the bundle of hair-like structures that protrude from the cell. These protrusions have mechanosensitive ion channels that allow hair cells to transform vibrational movements into electrical signals.
"We observed that the hair cells we produced are also able to develop similar protrusions, but with an immature and disorganised morphology," said the authors.

The research was published in the journal Development.