A new tool for creating hair cells in the ear that have been lost due to aging or noise

According to a new study, scientists have discovered a major gene that overcomes the main obstacle to the development of these cells and restores the ear’s hair cells to external or internal cells in order to restore hearing.

Investigators say “we overcame a major obstacle” to restore hearing.

  • The discovery of the gene allows the production of hair cells in the inner or outer ear
  • External hair cell death due to aging or noise can lead to hearing loss
  • The master gene transducer activates the development of the hair cell in the ear

Hearing loss due to aging, noise, and some cancer drugs and antibiotics has become irreversible because scientists have not been able to reprogram dead cells to the sensory cells of the outer and inner ear, which are necessary for hearing.

However, scientists in northwestern medicine have overcome a major obstacle to the development of hearing cells by finding the only major gene that programs hair cells in the outer or inner cells, according to a new study published today (May 4, 2022). ) in the magazine nature.

“Our findings allow us to make the first obvious cell replacement to compare one type of cell to another,” said study author Jamie Garcia-Anoveros, PhD, professor of anesthesiology and neurology, and Ken and Ruth Davy in the neurology department. “It provides a tool that was previously unavailable for making internal or external hair cells. We overcame a big obstacle. ”

In the United States, approximately 8.5% of adults between the ages of 55 and 64 have lost their hearing. This increases to almost 25% of those aged 65 to 74 and 50% of those aged 75 and older, according to the Centers for Disease Control (CDC).

Scientists are now able to produce artificial hair cells, but they are no different from internal or external cells, each of which performs a variety of important functions to produce hearing. The discovery is a major step towards the development of these known cells.

“It’s like a ballet” when the cells bend and jump

The death of the outer hair cells produced by the cochlea is often the cause of deafness and hearing loss. Cells do not develop or multiply in the embryo. In response to the pressure of sound waves, the outer hair cells expand and contract, amplifying the sound for the inner hair cells. The inner cells transmit these oscillations to neurons to produce the sounds we hear.

Jaime Garcia-Anoveros

Jaime García-Añoveros PhD, Professor of Anesthesiology, Neurology and Neurology and co-author of the study published in the journal Nature. Credit: Northwestern University

“It’s like ballet,” says Garcia-Anveros, describing the coordinated movement of inner and outer cells. “Outsiders bend down, jump, and lift their bellies up to their ears. The ear is a wonderful organ. There is no other organ in which mammalian cells are so precisely located. (I say with micrometric accuracy). Otherwise, there will be no hearing. ”

Master Gene Substitute Northwest Scientists Determine Ear Hair Cell Programs TBX2. When a gene is expressed, the cell becomes an inner hair cell. When the gene is closed, the cell transforms into an outer hair cell. The ability to produce one of these cells requires a cocktail gene, Garcia-Anoveros said. The ATOH1 and the GF1 The genes are needed to make a cochlear hair cell from a non-hairy cell. After that TBX2 would be turned on or off to produce the desired inner or outer cell.

The goal is to reprogram the supporting cells that hold the retina between the hair cells and provide them with structural support to the outer or inner hair cells.

“Now we can figure out how to make the inner or outer hair cells and why the latter are more prone to death and lead to deafness,” Garcia-Anoveros said. He stressed that this study is still in the experimental stage.

Reference: “Tbx2 – the main regulator of internal and external hair cell differentiation” – Jaime Garcia-Anoveros, John C. Clancy, Chuan Zhi Fu, Ignacio Garcia-Gomez, Yinji Zhou, Kazuaki Homma, Mary Ann Chitam and Anne Dug nature.
DOI: 10.1038 / s41586-022-04668-3

Co-lead author Anne Duggan, PhD, Assistant Professor of Anesthesiology, among other Northwestern writers; John C. Clancy, Garcia-Anoveros, and Duggan Laboratory Researcher; Chuan Zhi Fu, a graduate student at Driskill’s Master of Science in Life Sciences (DGP); Ignacio Garcia Gomez, PhD, Assistant Professor of Anesthesiology; Yingji Zhou, PhD, Assistant Professor of Neurology; Kazuaki Homma, PhD, Assistant Professor of Otolaryngology – Head and Neck Surgery; and Mary Ann Chitam, PhD, research professor of communications at the Weinberg College of Arts and Sciences.

Research Grants R01 DC015903 and R01 DC019834 funded by the National Institute of Deafness and Other Communication Disorders.

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