Overview

This year, we designed an audiogenetics system to explore the secret of sound sensing inspired by the status of hearing loss issues all over the world. Our human practice naturally focused on the combination of our lab works and prompting global concern about hearing-impaired people.

We educated people with synthetic biology concepts in a multi-dimensional manner. We also designed and distributed questionnaires and booklets for investigation, propagation, science popularization and call on awareness, which addressed the importance of our project. Through a series of interviews, we harvested many information about hearing loss including policies, medication, research and philanthropy. The knowledge about hearing formation also helped us promote our project.

More importantly, we tried to organize commonweal activities and cooperate with APP developers to further improve our human practice.

Human practice always gave us new ideas about how to improve our project. The integration of experiments and human practice made our “Cearll’s Secret” a more complete story.

Background

Hearing loss, also known as hearing impairment, is a worldwide problem. There are about 360 million hearing-impaired people around the world, accounting for 5% of the world’s total population.^[1] In China, people with hearing impairment take more than 1.67%, ranking at top of the whole disabled groups.

Worldwide hearing loss status. Asian hearing-impaired population accounts for a large part of the overall group with hearing loss. The number of people with hearing loss increases by year.^[2]

However, after communicating with relatives or friends that suffer or have ever suffered deafness, we found that, although the concerns by the international community are rising, there is still few efficient way to cure deafness.

There are many contributing causes of hearing problems .^[3] :

1. Cochlear damage due to prolonged exposure to loud noise ("noise induced hearing loss" or "industrial deafness").
2. Lack of good muscle tone in the middle ear, caused by stress or poor diet.
3. Poor central auditory processing
4. Psychological factors - not willing to hear, and thus shutting down the ability to communicate.
5. Otosclerosis - overgrowth of the cochlear bone which results in fusing the stapes to the cochlea.

New therapies (e.g. electrical devices, medication) are also keeping coming up year after year. Yet, the majority of people have hearing impairment still cannot be fully cured (Here, “cure” means “one can have similar level of hearing ability to common ones”) due to these limitations:

1. Hearing-aids: Long-term risk (amplified sound may induce greater damage to inner structures).
2. Cochlear implant: Only for patients with neural residue; high cost; long-term risk (damage for different hearing frequency range, especially for frequency below 1000Hz)
3. Medication: Normally use traditional Chinese medicine; long treatment cycle; unclear mechanisms; less effects, only used for short-period deafness.
4. Operation: Not recommended. Less effects; high risk; high cost; potential to cause sequela.

Thus, we would like to use genetic methods to change mini-structures on ear cells to see whether there may be effects expected to shade light on several kinds of deafness in future.

The basic structure of Cochlear implant.^[4]

Our Human Practice plan set out 2 objectives:

1. Improve awareness and understanding of Hearing loss
   • Survey on citizens awareness of Deafness (questionnaires)
   • Propagation of pathogeny and therapy (leaflets and aid-education)
2. Investigate social reality of Hearing loss
   • Policy and Law
   • Medication and Scientific Research
   • Charities

Our project focused on the enhancement of a mechanosensitive channel called TRPC5. Since TRP channel had been found hair cells in ears ^[5] , our work may enlighten future deafness therapy. In our project, we are developing a modified TRPC5 by random mutagenesis at specific region of the channel. With the accumulation effects of random mutagenesis (error-prone PCR), we may generate the TRPC5 mutant that has the highest fitness of the protein landscape ^[6] .

References:

1. ↑ Oishi, N., Schacht, J., Emerging treatments for noise-induced hearing loss, Expert opinion on emerging drugs, Retrieved from http://www.tandfonline.com/doi/abs/10.1517/14728214.2011.552427.
2. ↑ S. Rakholiya, S. Savaliya, A. Marar, M. Donasiya, Hearing Loss——A growing problem that affects quality of Life., EON Meditech Pvt. Ltd., Retrieved from http://www.eonmeditech.com/hearing-loss.html.
3. ↑ sina news, Retrieved from http://www.soundtherapyperth.com/benefits/hearing.php.
4. ↑ mayoclinic, Retrieved from http://www.mayoclinic.org/tests-procedures/cochlear-implants/multimedia/how-cochlear-implants-work/img-20008676.
5. ↑ Boris Martinac, Mechanosensitive ion channels: molecules of mechanotransduction, Journal of Cell Science 117, Retrieved from http://jcs.biologists.org/content/117/12/2449.abstract.
6. ↑ Paul A Dalby, Strategy and success for the directed evolution of enzymes, Current Opinion in Structural Biology, Retrieved from https://www.researchgate.net/publication/51229641_Strategy_and_success_for_the_directed_evolution_of_enzymes.