R01DC019426

Title: Mechanisms of Protection from Noise-Induced Hearing Loss

Abstract:
The cellular and molecular bases underlying noise-induced hearing loss (NIHL), the second leading cause of hearing loss globally, are not yet understood, presenting a barrier to the prediction of risk, prevention, and treatment of this debilitating disease. 1.1 billion young people (aged between 12-35 years) are at risk of hearing loss due to exposure to noise in recreational settings. Among service members of Operation Enduring Freedom and Iraqi Freedom, NIHL and its associated tinnitus are the top two diagnoses, and unaddressed hearing loss poses an annual global cost of $750 billion US dollars. Noise attenuation and hearing aids currently represent the only measures for protection and treatment, respectively.

It is now clear that cochlear synaptic loss precedes hair cell loss at low-moderate noise exposures (nonexplosive), effectively silencing affected neurons. Our laboratory and others have illuminated genetic mechanisms that modify sensitivity to NIHL in mice and humans. Through mouse GWAS, we have identified a critical gene, PRKAG2, encoding the G2 subunit of the AMPK complex. We find that damaging noise leads to nuclear AMPK activity specifically in inner hair cells and that PRKAG2 deficient mice are susceptible to NIHL due to greater instability of the inner hair cell presynaptic ribbon. There is an urgent need to identify directed therapies aimed at the prevention and/or repair of cochlear damage from noise exposure, for which an understanding of the underlying mechanisms is an obligate prerequisite.

Toward the long-term goal of developing targeted therapies for the prevention and/or correction of noise-induced synaptopathy, we now seek to decipher the pathways and mechanisms linking nuclear AMPK activity in inner hair cells to NIHL. Based upon our preliminary data, our central hypothesis is that AMPK becomes activated and trapped in the nucleus of inner but not outer hair cells by intranuclear phosphorylation after noise exposure and subsequently regulates the expression of downstream targets that impact the number and volume of presynaptic ribbons. Using a combination of genetics, physiology, cell biology, biochemistry, and structural biology, we propose the following three aims: the identification of cellular factors associated with susceptibility to NIHL (Aim 1), the molecular basis of nucleocytoplasmic shuttling of AMPK (Aim 2), and the identification of additional factors in the AMPK pathway leading to susceptibility to NIHL (Aim 3).

As the AMPK pathway is fundamental to cell survival, metabolism, gene regulation, and hearing, and is targetable, the completion of these aims has the potential to lead to meaningful interventions for this debilitating condition.

San Diego University Of California

TO INVESTIGATE SOLUTIONS TO PROBLEMS DIRECTLY RELEVANT TO INDIVIDUALS WITH DEAFNESS OR DISORDERS OF HUMAN COMMUNICATION IN THE AREAS OF HEARING, BALANCE, SMELL, TASTE, VOICE, SPEECH, AND LANGUAGE. THE NATIONAL INSTITUTE ON DEAFNESS AND OTHER COMMUNICATION DISORDERS (NIDCD) SUPPORTS RESEARCH AND RESEARCH TRAINING, INCLUDING INVESTIGATION INTO THE ETIOLOGY, PATHOLOGY, DETECTION, TREATMENT, AND PREVENTION OF DISORDERS OF HEARING AND OTHER COMMUNICATION PROCESSES, PRIMARILY THROUGH THE SUPPORT OF BASIC AND APPLIED RESEARCH IN ANATOMY, AUDIOLOGY, BIOCHEMISTRY, BIOENGINEERING, EPIDEMIOLOGY, GENETICS, IMMUNOLOGY, MICROBIOLOGY, MOLECULAR BIOLOGY, THE NEUROSCIENCES, OTOLARYNGOLOGY, PSYCHOLOGY, PHARMACOLOGY, PHYSIOLOGY, PSYCHOPHYSICS, SPEECH-LANGUAGE PATHOLOGY, AND OTHER SCIENTIFIC DISCIPLINES. THE NIDCD SUPPORTS: (1) RESEARCH INTO THE EVALUATION OF TECHNIQUES AND DEVICES USED IN DIAGNOSIS, TREATMENT, REHABILITATION, AND PREVENTION OF DISORDERS OF HEARING AND OTHER COMMUNICATION PROCESSES, (2) RESEARCH INTO PREVENTION AND EARLY DETECTION AND DIAGNOSIS OF HEARING LOSS AND SPEECH, VOICE, AND LANGUAGE DISORDERS AND RESEARCH INTO PREVENTING THE EFFECTS OF SUCH DISORDERS BY MEANS OF APPROPRIATE REFERRAL AND REHABILITATION, (3) RESEARCH INTO THE DETECTION, TREATMENT, AND PREVENTION OF DISORDERS OF HEARING AND OTHER COMMUNICATION PROCESSES IN THE ELDERLY POPULATION AND ITS REHABILITATION TO ENSURE CONTINUED EFFECTIVE COMMUNICATION SKILLS, AND (4) RESEARCH TO EXPAND KNOWLEDGE OF THE EFFECTS OF ENVIRONMENTAL AGENTS THAT INFLUENCE HEARING OR OTHER COMMUNICATION PROCESSES. SMALL BUSINESS INNOVATION RESEARCH (SBIR) PROGRAM: TO INCREASE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT, TO ENCOURAGE SMALL BUSINESS PARTICIPATION IN FEDERAL RESEARCH AND DEVELOPMENT, AND TO FOSTER PARTICIPATION OF SOCIALLY AND ECONOMICALLY DISADVANTAGED SMALL BUSINESS CONCERNS AND WOMEN-OWNED SMALL BUSINESS CONCERNS IN TECHNOLOGICAL INNOVATION. SMALL BUSINESS TECHNOLOGY TRANSFER (STTR) PROGRAM: TO STIMULATE AND FOSTER SCIENTIFIC AND TECHNOLOGICAL INNOVATION THROUGH COOPERATIVE RESEARCH AND DEVELOPMENT CARRIED OUT BETWEEN SMALL BUSINESS CONCERNS AND RESEARCH INSTITUTIONS, TO FOSTER TECHNOLOGY TRANSFER BETWEEN SMALL BUSINESS CONCERNS AND RESEARCH INSTITUTIONS, TO INCREASE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT, AND TO FOSTER AND ENCOURAGE PARTICIPATION OF SOCIALLY AND ECONOMICALLY DISADVANTAGED SMALL BUSINESS CONCERNS AND WOMEN-OWNED SMALL BUSINESS CONCERNS IN TECHNOLOGICAL INNOVATION.

93.173 - Research Related to Deafness and Communication Disorders

National Institute on Deafness and Other Communication Disorders (NIDCD) [HHS - NIH]

La Jolla, California 920371300 United States

Single Zip Code

NIH Research Project Grant (Parent R01 Clinical Trial Not Allowed) (PA-20-185)

Amendment Since initial award the total obligations have increased 363% from $773,286 to $3,581,311.