Researchers find proteins that might restore damaged sound-detecting cells in the ear

Using genetic tools in mice, researchers at Johns Hopkins Medicine say they have identified a pair of proteins that precisely control when sound-detecting cells, known as hair cells, are born in the mammalian inner ear. The proteins, described in a report published June 12 in eLife, may hold a key to future therapies to restore hearing in people with irreversible deafness.

“Scientists in our field have long been looking for the molecular signals that trigger the formation of the hair cells that sense and transmit sound,” says Angelika Doetzlhofer, Ph.D., associate professor of neuroscience at the Johns Hopkins University School of Medicine. “These hair cells are a major player in hearing loss, and knowing more about how they develop will help us figure out ways to replace hair cells that are damaged.”

In order for mammals to hear, sound vibrations travel through a hollow, snail shell-looking structure called the cochlea. Lining the inside of the cochlea are two types of sound-detecting cells, inner and outer hair cells, which convey sound information to the brain.

An estimated 90% of genetic hearing loss is caused by problems with hair cells or damage to the auditory nerves that connect the hair cells to the brain. Deafness due to exposure to loud noises or certain viral infections arises from damage to hair cells. Unlike their counterparts in other mammals and birds, human hair cells cannot regenerate. So, once hair cells are damaged, hearing loss is likely permanent.

Scientists have known that the first step in hair cell birth starts at the outermost part of the spiraled cochlea. Here, precursor cells start transforming into hair cells. Then, like sports fans performing “the wave” in a stadium, precursor cells along the spiral shape of the cochlea turn into hair cells along a wave of transformation that stops when it reaches the inner part of the cochlea. Knowing where hair cells start their development, Doetzlhofer and her team went in search of molecular cues that were in the right place and at the right time along the cochlear spiral.

Of the proteins the researchers examined, the pattern of two proteins, Activin A and follistatin, stood out from the rest. Along the spiral path of the cochlea, levels of Activin A increased where precursor cells were turning into hair cells. Follistatin, however, appeared to have the opposite behavior of Activin A. Its levels were low in the outermost part of the cochlea when precursor cells were first starting to transform into hair cells and high at the innermost part of the cochlea’s spiral where precursor cells hadn’t yet started their conversion. Activin A seemed to move in a wave inward, while follistatin moved in a wave outward.

“In nature, we knew that Activin A and follistatin work in opposite ways to regulate cells,” says Doetzlhofer. “And so, it seems, based on our findings like in the ear, the two proteins perform a balancing act on precursor cells to control the orderly formation of hair cells along the cochlear spiral.”

To figure out how exactly Activin A and follistatin coordinate hair cell development, the researchers studied the effects of each of the two proteins individually. First, they increased the levels of Activin A in the cochleas of normal mice. In these animals, precursor cells transformed to hair cells too early, causing hair cells to appear prematurely all along the cochlear spiral. In mice engineered to either overproduce follistatin or not produce Activin A at all, hair cells were late to form and appeared disorganized and scattered across multiple rows inside the cochlea.

“The action of Activin A and follistatin is so precisely timed during development that any disturbance can negatively affect the organization of the cochlea,” says Doetzlhofer. “It’s like building a house — if the foundation is not laid correctly, anything built upon it is affected.”

Looking more closely at why overproduction of follistatin results in disorganized hair cells, the researchers found that high levels of this protein caused precursor cells to divide more frequently, which in turn made more of them convert into inner hair cells in a haphazard way.

Doetzlhofer notes that her research in hair cell development, although fundamental, has potential applications to treat deafness caused by damaged hair cells: “We are interested in how hair cells evolved because it’s an interesting biological question,” she says. “But we also want to use that knowledge to improve or develop new treatment strategies for hearing loss.”

The research was supported by the National Institute on Deafness and Other Communication Disorders (DC011571, DC013477, DC012972 and DC016538) and the David M. Rubenstein Fund for Hearing Research.

Source: sciencedaily

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Minas Tsigos A
Minas Tsigos A
2021-03-19T14:43:24+0000
Σαν τραγουδιστής ακριβώς αυτό που θέλω σε ήχο ! Καλά μπάσα και ακόμα καλύτερα μεσαία ,καλή εφαρμογή στο αυτί ,καθόλου κουραστικά ακόμη και μετά από 3 ώρες live ,δεν θέλεις να τα βγάλεις από τα αυτιά σου! Και το σημαντικότερο ,άρτιο και άμεσο service που σε άλλες... εταιρείες θα το πλήρωνες χρυσό ! Value for money και πλέον η Soundz είναι η εταιρεία μου ,δεν την αλλάζω και την συστήνω ανεπιφύλακτα !read more
George Ahas Lignos
George Ahas Lignos
2021-02-09T07:01:42+0000
«These are by far the most phenomenal set of in-ears I’ve ever owned. They are beautiful, and they sound bloody awesome too. I use them while playing shows and in long studio sessions.The precision and accuracy right through the sonic range, is unparalleled with... anything else that I've ever tried. The high-quality armature and electrostatic drivers deliver crisp, punchy and extended frequencies. Their 3D-Fit process ensures the precision and reliability, and honestly feels like there is nothing in my ears.On stage or in the studio the most important thing for me, is to have clean frequencies. The incredible isolation and stereo image allows me to hear even subtle changes in volume, panning, EQ and dynamics.They have been such an incredible investment in my musical journey. I would highly recommend them to any musician, singer, producer or audiophile out there.”G.read more
Γιάννης Τσαμπάζης
Γιάννης Τσαμπάζης
2021-02-04T12:31:23+0000
Εξαιρετική κατασκευή, τέλεια εφαρμογή και άψογος ήχος με βαθύ μπασο και ελαφριά πρίμα. Απαραίτητο εργαλείο για τους επαγγελματίες.
Nikos Stadiatis
Nikos Stadiatis
2021-02-02T11:12:21+0000
Πλέον κάτοχος των IEM BOOST...Δεν έχω λόγια για την άψογη επικοινωνία και το φανταστικό αποτέλεσμα...Θα το πρότεινα ανεπιφύλακτα σε οποιονδήποτε!Φανταστικός ήχος,100% εφαρμογή και πλήρης στήριξη ανά πάσα στιγμή...Νομίζω η καλύτερη επιλογή που θα μπορούσα να κάνω!
Δημήτρης Φωτίου
Δημήτρης Φωτίου
2021-01-30T19:09:35+0000
Εξαιρετική ποιότητα κατασκευής, τέλεια εφαρμογή ακόμα και στα universal μοντέλα και ήχος που ανταποκρίνεται σε κάθε προσδοκία. Τα in ears της Soundz συστήνονται ανεπιφύλακτα!
Themis Koparanidis
Themis Koparanidis
2021-01-24T20:43:02+0000
Τα soundz ήρθαν να αλλάξουν τη φάση! Η αναζήτησή του τέλειου -κομμένου και ραμμένου- στα μέτρα μας ήχου αρχίζει και τελειώνει εδώ. Η σωστή εξισορρόπηση η ικανότητα για δύναμη όταν τη χρειαστείς χωρίς να στερηθείς ούτε μια συχνότητα και η απόλυτη εφαρμογή σε κάνουν να... τα νιώθεις σαν προέκταση του αυτιού σου. Η ποιότητα κατασκευής είναι απαράμιλλη και πραγματικά δυσκολεύτηκα να διαλέξω χρώμα ! Tόσα χρόνια απλά συμβιβαζόμουν με ακουστικά και δε το ήξερα ,και κάτι που έλειπε για μας τους επαγγελματίες είναι επιτέλους μια ΕΞΥΠΗΡΕΤΗΣΗ άμεση, ανθρώπινη από άρτια καταρτισμένο προσωπικό και αυτό είναι που σε κερδίζει από την πρώτη στιγμή! ⭐️⭐️⭐️⭐️⭐️read more
Nikos Koumoundouros
Nikos Koumoundouros
2021-01-22T19:12:57+0000
Λεπτομέρεια και ευκρίνεια στα καλύτερα τους! Άψογος ήχος, πανέμορφος σχεδιασμένο κομμένος και ραμμένος πάνω μας! Στερεοφωνία όπως πρέπει ακούγοντας όλο το φάσμα τέλεια! Ακομα, αξίζει να αναφέρω την άψογη και πολύ γρήγορη εξυπηρέτηση! 100% worth it! 👌👌
Kostas Milonas
Kostas Milonas
2021-01-22T15:54:45+0000
Από την στιγμή που θα πιάσεις στα χέρια σου τα ακουστικά της soundz θα διαπιστώσεις πως μόνο και μόνο από το καλοδουλεμένο design που έχουν είτε είναι φθηνό είτε ακριβό μοντέλο θα μπει το κερασάκι στην τούρτα με το που τα δοκιμάσει κανεις! Αναλόγως τη φωνή η το όργανο... που ασχολείται κάποιος σου δίνει τη δυνατότητα να βρεις αυτό ακριβώς που σου ταιριάζει! ⭐️⭐️⭐️⭐️⭐️read more
George Migas
George Migas
2021-01-21T15:54:36+0000
Ότι καλύτερο σε in ear monitor έχω χρησιμοποιήσει ποτέ. Σωστή συχνοτική ισορροπία με απόλυτο fitting στο αυτί για βέλτιστο αποτέλεσμα. Καταπληκτικό φινίρισμα και άριστη συσκευασία ολοκληρώνουν την εμπειρία. Το customer support δεν θα μπορούσε να είναι καλύτερο με άμεσο... service και ανταλακτικά μέχρι και απλό καθαρισμόread more
Πολυχρονιάδης Αντώνης
Πολυχρονιάδης Αντώνης
2020-01-01T18:48:35+0000
I bought a pair of soundz uni music earplugs, and although i am not a professional musician or a dj, i am happy to have made this decision.The plugs sit comfortably in the earchannel and do not bother you at all, even after 6 or 7 hours. In my personal experience, it... feels like it crops out clipping that medium quality speakers produce when put to maximum output power, and leave behind a deep bass and clear high frequences. The sound reduction can be chosen between -15 and -20 dBa (-20 for me), however once you wear them you can have normal conversation with people around you.As an amateur festival and event attender my only advice is to include the safety cord in your purchase, you don't want to be searching the ground for the plugs in a dancing crowd (and don't worry about looking like a lunatic with cords coming out of your ears, they are a great conversation starter)My overall experience is positive to say the least. Next day delivery and extra gifts from the company and a personalised thanikng letter really made want to recommend this brand and product to everyone who hates next-day ear-buzzing.read more
Giorgos Kakouros
Giorgos Kakouros
2019-04-30T13:13:31+0000
If not the most obviously one of the most useful products for people who works or just going-out often in clubs and parties or generally places with highlevel db which are harmful for the ears. Crystal sound, easy conversations in loud music and no buzz in your ears... after being in a party or a place with highlevel db! Thanks Soundz for giving me the option of partying with high quality and no buzzing!read more
Dimitris Mastrokolias
Dimitris Mastrokolias
2018-11-24T03:01:18+0000
Got a pair of Infernos today and I totally recommend them!Perfect fit, discreet and the switch is very practical in the late hours.
Kwstas Sfakianakis
Kwstas Sfakianakis
2018-04-18T12:12:59+0000
Perfect fit, top quality and also the best protection for your ears!!
Menelaos Fytilis
Menelaos Fytilis
2018-04-17T13:23:16+0000
Margaritis Thomas
Margaritis Thomas
2018-04-05T17:51:05+0000
Perfect fit, stylish and comfortable I always wear my Inferno when I am in the club. I can enjoy the music and protect my hearing at the same time.
Spyros Tabas
Spyros Tabas
2018-03-28T02:02:26+0000
Soundz Inferno! ��
Konstantinos Karagkounis
Konstantinos Karagkounis
2018-03-27T14:44:46+0000
Εξαιρετικές!
Σπύρος Κονοφάος
Σπύρος Κονοφάος
2018-03-26T08:42:39+0000
Peter Schreurs
Peter Schreurs
2018-01-15T18:56:51+0000
Perfect fit and no stress in your ears. Even when using a helmet! Using the Soundz earplugs for racing exceeding 110 Db in the cockpit! Perfect fit with the #COMM-PRO communication system!
John Lian Chaikalis
John Lian Chaikalis
2017-12-04T16:08:50+0000
Isuru Anushanga Vidanapathirana
Isuru Anushanga Vidanapathirana
2017-11-08T03:58:09+0000
Djbello Sifis Mountrakis
Djbello Sifis Mountrakis
2017-11-07T22:39:15+0000
Constatino John Tsioris
Constatino John Tsioris
2017-11-03T15:45:59+0000
Nacho González
Nacho González
2017-10-15T09:51:28+0000
Iuliàn Dragomir
Iuliàn Dragomir
2017-10-14T10:14:13+0000
Dimitris Nikopoulos
Dimitris Nikopoulos
2017-10-02T11:37:55+0000
Super!! :D
Chris Vigos
Chris Vigos
2017-06-24T20:11:22+0000
Christos Nikas
Christos Nikas
2017-04-17T14:09:34+0000
Andreas Athineos
Andreas Athineos
2017-04-10T11:42:17+0000
Fanis Nasiaras
Fanis Nasiaras
2017-04-07T20:08:27+0000
Panos Gerontakis
Panos Gerontakis
2017-04-07T17:25:23+0000
Konstantinos Anassis
Konstantinos Anassis
2017-04-07T11:35:52+0000
Top Product, Top Customer Service. #loveyourhearing
Tassos Papagiannoulis
Tassos Papagiannoulis
2017-04-06T18:50:55+0000
Top quality products, highly recommended to all sound lovers !
Giorgos Karadimitris
Giorgos Karadimitris
2017-03-08T00:49:25+0000
Ελενη Τεγου
Ελενη Τεγου
2017-01-14T21:48:42+0000
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Theodoros Fotos
2016-10-31T18:20:53+0000
Giannis Gianakis Gianoulis
Giannis Gianakis Gianoulis
2016-10-28T13:06:54+0000
Ανδρέας Στεριώτης
Ανδρέας Στεριώτης
2016-10-21T12:01:30+0000
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Petros Manganaris
2016-10-10T21:14:01+0000
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