PRESS RELEASE 
CELLULAR ARCHITECTURE FOR HEARING REGENERATION 
Researchers from the Centre for Genomic Regulation discover the mechanism by which some animals can regenerate their sensory organs. 
The findings, published in the journal Development, provide a framework for the development of new strategies in regenerative medicine for the improvement of conditions such as hearing loss due to age, peripheral neuropathy, or strokes.
Hair cells are substantially similar in their development and physiology across species. However, while the loss of hair cells in humans is irreversible and leads to permanent hearing loss, other vertebrates have the ability to regenerate these cells their entire lives. The Sensory Cell Biology and Organogenesis laboratory, led by Hernán López-Schier at the Centre for Genomic Regulation, has studied the mechanisms which enable the regeneration of hair cells in zebrafish and, in particular, the recuperation of the architecture of the sensory organs.
Their recent results, published in the journal Development, reveal that the regeneration of the hair cells in the lateral line of the zebrafish (a sensory organ analogous to the inner ear in mammals), the acquisition of cell fate and tissue architecture are processes that run simultaneously in order to allow the functional recovery of hair cells before complete anatomical repair. This may be essential for the survival of these animals.
Researchers have discovered that the process linking the acquisition of cell fate with tissue organisation lies in the development of the hair cell progenitors. "The findings published in this paper show that the proliferation of progenitor cells is of great importance for regeneration" explains Hernan Lopez-Schier, principal investigator in the study. "Now we understand the mechanism by which some animals can maintain their sensory abilities throughout their whole lives. We hope these discoveries will help in the development of strategies for regenerative medicine and in this way improve certain problems such as loss of hearing and balance in humans", adds Lopez-Schier.
Furthermore, using high-resolution in vivo images of transgenic zebrafish, they have discovered new cellular behaviour at a tissue level which they have called planar cell inversion”. This cellular behaviour reveals a mechanism that could be the key to maintaining cellular orientation in other plastic tissues with a high cell turnover such as the kidneys, lungs or brain ventricles.
¿Why are architecture and polarity of the tissues important?
The three-dimensional organisation of tissues is essential for an efficient function of organs. This organisation must be maintained throughout the whole life of the individual and recovered during organ repair, as its loss could lead to devastating pathologies in humans.
The study presented by researchers of the Centre for Genomic Regulation, is focused on the architecture and arrangement of the tissues in order to explain the regenerative mechanism of auditory hair cells with the zebrafish as the animal model. 

Reference work: Wibowo I., Pinto-Texeira F., Satou C., Higashijima S. and López-Schier H. Compartimentalized Notch signaling sustains epithelial mirror symmetry. Development (2011), doi:10.1242/dev.060566
Complimentary material published with the study: See here some videos of sensory organ regeneration (one of them appears as the highlighted video of the week on the main page of Development)
 
For more information: Laia Cendrós, Centre for Genomic Regulation (CRG). Tel. +34 93 316 02 37.