NIH Funds Miller School Researcher’s Novel Work to Develop Gene Therapy for Hearing Loss-related Usher Syndrome

The National Institute on Deafness and Other Communication Disorders (NIDCD) has awarded Xue Zhong Liu, M.D., Ph.D., Marian and Walter Hotchkiss Endowed Chair in Otolaryngology at the University of Miami Miller School of Medicine, a five-year, $3.5 million R01 research grant to develop a precision medicine approach to treat hearing loss (HL) in Usher syndrome (USH).

There is no cure for USH, and current treatments inadequately address this inherited condition that can cause not only HL but also vision loss.

“Today’s treatment for Usher syndrome is limited to cochlear implants or hearing aids, which help to address the hearing loss, but there is no biological treatment for HL and the blindness. There is an unmet need to develop alternative treatment options,” Dr. Liu said.

The NIH grant will fund Miller School research aimed at developing and testing novel therapy approaches with gene editing. Gene editing is a group of technologies that allow scientists to change an organism’s DNA. CRISPR-Cas9 is a popular gene editing technology developed to treat genetic disorders.

“The Miller School is one of a select few sites in the world conducting research to apply CRISPR/Cas9 gene editing for HL including Usher syndrome,” said Dr. Liu, who also is vice chair of the Department of Otolaryngology and professor of otolaryngology, human genetics, biochemistry, and pediatrics at the Miller School.

Gene- and Cell-based Therapies Offer Promise

Gene- and cell-based therapies using genome editing offer the promise of treatment for a variety of inherited disorders but have not been used successfully for human hereditary HL, including Usher syndrome.

Dr. Liu, along with his collaborator Dr. Zheng-Yi Chen from the Massachusetts Eye and Ear Infirmary, Department of Otolaryngology, Harvard Medical School, aim to pave the way for the development of gene therapy approaches that would address HL Usher syndrome patients’ hearing.

“We will use CRISPR/Cas9 to correct mutations in three different Usher genes shown in our preliminary data to cause most inherited hearing loss in USH,” he said. “This will involve strategies to rescue hearing in transgenic USH mouse models and developing CRISPR/Cas9 editing strategies to disrupt USH mutations, using human inner ear organoids derived from patient-induced pluripotent stem cells.”

Ear Institute, Bascom Palmer Collaborating

The NIH-funded study could lead to patient-specific treatment, based on a patient’s USH genetic mutations. In the meantime, Dr. Liu has developed a collaborating program with the University of Miami Ear Institute and Bascom Palmer Eye Institute to provide better care for people with Usher syndrome.

“Recent breakthroughs in genetic screening, gene- or cell-based therapeutics, and gene editing for the inner ear can lead to novel therapies for multiple classes of hereditary hearing loss. We are excited as this is the first gene therapy NIH grant using CRISPR/Cas9 at UM for common sensory disorders,” said Fred Telischi, M.D., M.E.E., chair of otolaryngology, professor of neurological surgery and biomedical engineering, and the James R. Chandler Chair in Otolaryngology.

“This grant was awarded by the NIDCD as part of its high-impact program to help meet an unmet patient need,” Dr. Liu said. “Our aim is to lay the foundation for moving genome editing approaches closer to clinical trials on humans with Usher syndrome, which accounts for about 50% of all hereditary deaf-blindness cases, including in children.”

The Genetic Hearing Loss Clinic at University of Miami Ear Institute is a multi-disciplinary program that provides diagnostic, molecular testing, genetic counseling, and intervention options for patients and families who are dealing with various types of HL.