Medical

"Master" switch for ear cell programming offers new hope for hearing loss

"Master" switch for ear cell p...
The identification of a gene responsible for ear hair cell differentiation could lead to treatments for hearing loss
The identification of a gene responsible for ear hair cell differentiation could lead to treatments for hearing loss
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The identification of a gene responsible for ear hair cell differentiation could lead to treatments for hearing loss
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The identification of a gene responsible for ear hair cell differentiation could lead to treatments for hearing loss

Scientists studying the mechanisms behind deafness have pinpointed a single gene they describe as a type of master switch for cell differentiation, opening up exciting new possibilities around restoration of hearing. The discovery is claimed to "overcome a major hurdle" in the field, and lays the basis for therapies that tackle a common cause of irreversible hearing loss.

The study focuses on ear hair cells, which are sensory cells that line the inner ear and are fundamental to our sense of hearing. The death of these cells due to aging and stresses like excessive noise leads to an irreversible deterioration of hearing, and for this reason these hair cells are a key focus for scientists pursuing regenerative forms of treatments.

In 2020 we saw an interesting advance in this area, with scientists zeroing in on a single protein that can determine whether embryonic hair cells mature in a healthy manner or develop into something else. The hope is that this knowledge can lead to treatments that regenerate the vital hair cells and restore hearing, and this new study follows a similar line of thinking.

The research actually centers on the different roles inner and outer hair cells play in hearing, and the gene that dictates the creation of one over the other. Outer hair cells develop in the embryo and don't reproduce. In the ear, they expand and contract as they encounter sound waves, amplifying sound for the inner hair cells that pass vibrations on to the neurons to create what we interpret as sound.

“It’s like a ballet,” explained lead author Jaime García-Añoveros from Northwestern University. "The outers crouch and jump and lift the inners further into the ear. The ear is a beautiful organ. There is no other organ in a mammal where the cells are so precisely positioned. Otherwise, hearing doesn’t occur.”

Through experiments on mice, the scientists have landed on what they describe as a master regulator of inner versus outer hair cell differentiation. Called TBX2, the team found when the gene was expressed ear hair cells became inner hair cells, and when the gene was blocked they became hair cells of the outer variety.

“Our finding gives us the first clear cell switch to make one type versus the other,” said García-Añoveros. “It will provide a previously unavailable tool to make an inner or outer hair cell. We have overcome a major hurdle.”

Scientists have previously demonstrated an ability to generate artificial hair cells, but not an ability to differentiate them into inner or outer cells. To actually flip the switch uncovered in this research, the scientists would need to come up with a gene cocktail to reprogram other cells, with the structural support cells latticed throughout the hair cells in the ear among the prime candidates.

“We can now figure out how to make specifically inner or outer hair cells and identify why the latter are more prone to dying and cause deafness,” García-Añoveros said.

The research was published in the journal Nature.

Source: Northwestern University

5 comments
5 comments
1stClassOPP
I woke up one morning, in my 40s, went to work and found I was unable to hear the telephone conversation in my left ear, and lots of noise in my head(tinnitus?) I had lots of tests done but got no explanation for this. I blame it on the radar emissions from a speed measuring device hanging out of the left rear windows of a police car for years. I’m interested in this article because maybe there’s some hope of restoring my hearing in my left ear. I’d love to be the “Guinea pig” to experiment with the topic on the table.
CAVUMark
I would love for this to help cure tinnitus. Not hearing is one thing, but to have a constant buzzing in your head is another. Send help.
Korina57
Guns, Guitars, Power Tools as well as working as a Nightclub DJ in the 80's all contributed to my so so ability to hear well in different acoustic situations. Even thought my hearing is frequency compromised, my location interpretation still remains good when I close my eyes. I'm game to be part of this cutting edge procedure.
mattlass
@ 1stClassOPP:
I have resolved about 90% of my tinnitus by doing a few things. I had sudden sensorineural hearing loss one summer day and the ENT prescribed 2 medpack steroid tapers one after another. Nothing. With years of thinking about it, I approached it as a periodontal disease sympton. I used three products. The first is NanoSoma spray. I bought 3 bottles that cost about $150 for the three bottles. Then I used a xylitol nasal spray called XLEAR. Three or four nasal sprays in each nostril 2 or three times per day. Last, but very effective was putting a couple of drops of cinnamon oil on my toothbruch everytime I brushed. I was right that it was periodontal in origin. Try these things. It may simply be oral infections because being in your 40's is young for that kind of damage, unless you were loading shells into a howitzer.
Eggster
@1stClassOPP Look into viral infections of the cochlea as a likely cause. It can't be diagnosed directly, only via a process of elimination. In a nutshell, a viral infection causes inflammation inside the cochlea and this causes the hairs inside the cochlea to be bent and compressed, drastically diminishing hearing. The resulting damage will cause some degree of permanent hearing loss if untreated for more than ~3 days.