HRP_logo for web.jpg

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.

The question is not if we will regenerate hair cells in humans, but when.
— HRP Scientific Director Peter Barr-Gillespie, Ph.D.

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.

Identifying genes that trigger regeneration in neighboring cells is crucial, as activation of these genes might be able to trigger regeneration in mammals. Once we identify where this signaling cascade is blocked, we can design therapies to circumvent this block and trigger regeneration.
— HRP Scientist Tatjana Piotrowski, Ph.D.

Webinars and Videos

The Path to a Cure for Hearing Loss and Tinnitus - May 21, 2015

Download Full Transcript Here

Unlocking the Potential for Hair Cell Regeneration - Nov. 5, 2015

Download Full Transcript Here

Are Hair Cell Regeneration Genes Blocked? - March 8, 2016

Download Full Transcript Here




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.


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.


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.


Peter Barr-Gillespie Ph.D.
Scientific Director, Hearing Restoration Project - Professor of Otolaryngology, Oregon Health & Science University
Studying mechano-electrical transduction by hair cells, the sensory cells of the inner ear.
Read More

Seth Ament, Ph.D.
Assistant Professor, Department of Psychiatry, aculty Member, Institute for Genome Sciences, University of Maryland School of Medicine
Investigating integrated systems biology of hearing restoration
Read More

John Brigande, Ph.D.
Associate Professor of Otolaryngology, Oregon Health & Science University
Developing methods to control gene expression in the inner ear; identifying genes critical for development of the ear.
Read More

Alain Dabdoub, Ph.D.
Scientist, Sunnybrook Research Institute
Discovering and characterizing the molecular signaling factors responsible for the development of the mammalian inner ear.
Read More

Albert Edge, Ph.D.
Professor of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School
Researching stem cells and the basic mechanisms of cellular repair in the nervous system; studying the loss of sensory cells in the inner ear that result in deafness due to excessive noise, drugs, disease, or aging.
Read More

Andy Groves, Ph.D.
Professor of Neuroscience, Baylor College of Medicine
Using the inner ear as a model system to address fundamental questions in developmental biology and regeneration; using chick embryology and mouse genetics to address these problems.
Read More

Stefan Heller, Ph.D.
Professor of Otolaryngology-Head and Neck Surgery, Stanford University
Developing solutions for reversing sensory hair cell loss in the mammalian cochlea using stem cell-based approaches.
Read More

Ronna Hertzano, M.D., Ph.D.
Associate Professor of Otorhinolaryngology, Head & Neck Surgery, University of Maryland School of Medicine
Identifying targets for prevention of age and noise/ototoxic induced hearing loss and developing tools for sharing and presenting gene expression data.
Read More

Michael Lovett, Ph.D.
Professor and Chair of Systems Biology, National Heart & Lung Institute, Imperial College London
Applying genomics to hair cell regeneration in the inner ear
Read More

Tatjana Piotrowski, Ph.D.
Associate Investigator, Stowers Institute for Medical Research
Determining how the zebrafish inner ear induces hair cell regeneration.
Read More

David Raible, Ph.D.
Professor of Biological Structure, University of Washington
Examining how neural crest cells, like those in the zebrafish lateral line, develop.
Read More

Yehoash Raphael, Ph.D.
R. Jamison and Betty Williams Professor of Otolaryngology, University of Michigan
Determining how to restore hair cells and hearing in deaf guinea pigs by injecting into the inner ear a gene that triggers the growth of hair cells during embryonic development.
Read More

Neil Segil, Ph.D.
Research Associate Professor, Broad/CIRM Center for Regenerative Medicine and Stem Cell Biology, University of Southern California
Studying development aspects of cell cycle regulation in relation to the inner ear, hearing loss, and regeneration.
Read More

Jennifer S. Stone, Ph.D.
Research Professor of Otolaryngology-Head and Neck Surgery, University of Washington
Investigating cellular and molecular mechanisms guiding embryonic and post-embryonic production of sensory hair cells in birds.
Read More

Mark Warchol, Ph.D.
Professor of Otolaryngology, Washington University School of Medicine
Examining development and regeneration of sensory receptors and afferent neurons in the inner ear.
Read More


HHF established a Scientific Advisory Board (SAB) to provide oversight and guidance to the HRP Consortium. The SAB comprises senior scientists in hearing science, regenerative biology, and related fields. This Board evaluates HRP projects for funding and monitors the performance of funded projects against the goals of the projects. Meet our SAB members below.

Bryan E. Crenshaw, Ph.D.
Children's Hospital of Philadelphia
Director of Basic Science Research, Division of Otolaryngology
Director of Basic Research, Center for Childhood Communication Scientist, Mammalian Neurogenetics Group
Adjunct Associate Professor of Otorhinolaryngology, Head and Neck Surgery, Perelman School of Medicine at the University of Pennsylvania

Lisa Goodrich, Ph.D.
Harvard Medical School
Professor of Neurobiology

David Ornitz, M.D., Ph.D.
Washington University
Alumni Endowed Professor, Department of Developmental Biology Developmental Biology Program

David Pauls, Ph.D.
Massachusetts General Hospital
Professor of Psychiatry
Psychiatric & Neurodevelopmental Genetics Unit Center for Human Genetic Research

Edwin Rubel, Ph.D.
University of Washington
Department of Physiology and Biophysics, Department of Otolaryngology, at the Graduate Program in Neurobiology and Behavior, and the Virginia Merrill Bloedel Hearing Research Center at University of Washington

Doris Wu, Ph.D.
National Institute on Deafness and Other Communication Disorders
Chief, Section on Sensory Cell Regeneration and Development
Chief, Laboratory of Molecular Biology