“Interestingly, the new study has shown that all supporting cells do not behave the same, and so some cells may be more amenable to regenerative therapies than others,” said Neil Segil, Ph.D., a senior author and principal investigator at House Ear Institute.
Specifically, one type of supporting cells, the so-called pillar cells, are resistant to the loss of Notch signaling. So, even when Notch signaling is blocked, pillar cells do not turn into hair cells.
While sensory hair cells in the inner ear (cochlea) of birds and other lower vertebrates have the ability to regenerate after being deafened, the sensory hair cells in the cochlea of humans and other mammals cannot. The causes of this failure of regeneration has long been the holy grail in the world of hearing loss research. Currently, there is no cure for sensorineural hearing loss, whose widespread occurrence is largely the result of damage to the cochlea’s sensory hair cells from injury, aging, certain medications or infection.
In a study reported in Nature in June 2006, House Ear Institute (HEI) researchers discovered that some cells in the mouse inner ear known as supporting cells, like their counterparts in birds and reptiles, are able to turn into hair cells, at least for a short time after birth. This discovery gave new hope to the quest for regenerative therapies for hearing loss. However, the mechanisms underlying the change from supporting cell into hair cell, the basis of regeneration in birds and reptiles, remains unknown.
Pillar cells are a highly specialized supporting cell type that matures to form the tunnel of Corti in the inner ear and are essential for cochlear function. In the organ of Corti, the pillar cells are located between the inner and outer hair cells.
Researchers determined that the resistance to loss of Notch signaling is caused by a gene known as Hey2, which is present in the pillar cells, and is necessary for pillar cells resisting turning into hair cells. Hey2 is a member of a family of genes, and the data suggests that other members of this family are present in different supporting cell types in the early postnatal organ of Corti and help define different subpopulations of supporting cells, with Hey2 defining pillar cells.
Also reported for the first time in this study, the team identified FGF, fibroblast growth factor, as a regulation factor for Hey2 in pillar cells. The researchers hypothesize that FGF released from inner hair cells maintains Hey2 expression and contributes to the establishment of the pillar cell region, which divides inner from outer hair cells, a crucial function in a developing ear.
This newly described function of Hey2 in resisting the loss of Notch signaling is likely to influence the thinking about the role of this important biochemical pathway in many other developing embryonic cell types, such as the segmental development of the spinal column, and the differentiation of the cells of the brain.
Segil along with co-author Andy Groves, Ph.D., associate professor of neuroscience and genetics at Baylor College of Medicine, and lead author Angelika Doetzlhofer, Ph.D., think that the role of Hey2 may help explain some of the evolutionary changes that have occurred in the inner ear of vertebrates, such as the existence of multiple rows of pillar cells in our distant relatives the duck-billed platypus. These same mechanisms may help explain how the separation of the inner and outer hair cells is maintained and possibly how these cell types were able to evolve independently.
About the House Ear Institute
The House Ear Institute (HEI) is a non-profit 501(c)(3) organization dedicated to advancing hearing science through research and education to improve quality of life. HEI scientists investigate the cellular and molecular causes of hearing loss and related auditory disorders as well as neurological processes pertaining to the human auditory system and the brain. Our researchers also explore technology advancements to improve auditory implants, hearing aids, diagnostic techniques and rehabilitation tools. The Institute shares its knowledge with the scientific and medical communities as well as the general public through its education and outreach programs.
Kirsten Holguin | Newswise Science News
Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT
Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
07.12.2016 | Health and Medicine
07.12.2016 | Life Sciences
07.12.2016 | Health and Medicine