A GOAL TO CURE HEARING LOSS
Hearing Health Foundation (HHF)’s Hearing Restoration Project (HRP) is the first international research consortium focused on investigating hair cell regeneration as a cure for hearing loss and tinnitus.
The overarching principle of the HRP consortium is cross-discipline collaboration: open sharing of data and ideas. By having almost immediate access to each other’s data, HRP scientists are able to perform follow-up experiments much faster, rather than having to wait years until data is published.
Primary treatments for hearing loss have been hearing aids and cochlear implants. While these have been successful, they have limitations. Most people who have lost hearing have done so through noise damage or aging, and may be candidates for hair cell regeneration or restoration.
The HRP uses three different animal models for studying inner ear hair cell regeneration. Two of those models, the chick and zebrafish, show robust hair cell regeneration. If the hair cells of a chick or a fish are damaged, within a short time—only a day or two for the fish, a few weeks for the chick—new hair cells are formed. That’s a spectacular result, and it tells us that animals are capable of regenerating hair cells.
The mouse is our other experimental model. Like in humans, the mouse shows no hair cell regeneration; once damaged, hair cells are not restored. But if we use what we know about fish and birds to determine how to regenerate hair cells in the mouse, then we will be able to regenerate hair cells in people.
WHO COMPRISES THE HRP?
The HRP consortium is formed by top-tier auditory and vestibular research professionals at Baylor College of Medicine, Imperial College London, Mass. Eye and Ear, Oregon Health & Science University, Stanford University, Stowers Institute for Medical Research, Sunnybrook Research Institute, University of Maryland School of Medicine, University of Michigan, University of Southern California, University of Washington, and Washington University School of Medicine. Read about each HRP consortium member's scientific focus areas and interest in Spotlight On.
ANNUAL PROJECTS & THE HRP's THREE-PART STRATEGIC RESEARCH PLAN
PHASE 1 - DISCOVERY RESEARCH:
Compare the fish, chick, and mouse to discover pro- or anti-regeneration pathways and determine supporting cell fates.
So far, scientists have identified various pathways for hair cell regeneration. Since there are many potential gene targets, they continually utilize bioinformatics methods to winnow down and determine which are most relevant. Researchers have shown in the mouse neighboring supporting cells remain after deafening.
PHASE 2 - PATHWAY VALIDATION:
Verify animal model pathways and describe regeneration strategies.
Recent technological advances have enabled researchers to examine single hair cells rather than entire clusters. This aids our focus our study on gene expression immediately after a single hair cell is damaged. The question now being asked is, what are the early events that occur in the hair cells of zebrafish and chicks, but not in mice, before the hair cells die? The genes not undergoing the same expression in the mouse as in the other two animal models will be targets for manipulation.
PHASE 3 - DEVELOP TREATMENTS:
Identify drugs to trigger hair cell regeneration in mammals.
Experimental models from Phase 2 will be used to screen for drugs—using the mouse model first.