Researchers from the German Primate Center—Leibniz Institute for Primate Research, the University Medical Center Göttingen, and the Max Planck Institute for Multidisciplinary Sciences have created the first primate model for studying genetic deafness caused by defects in the OTOF gene. The study, published in Nature Communications, marks a major step forward in understanding congenital hearing loss and developing targeted therapies.
The Role of the OTOF Gene in Hearing
Hearing loss is one of the most common congenital sensory disorders worldwide. In many cases, the condition arises from defects in the OTOF gene, which plays a critical role in the hearing process.
The OTOF gene produces a protein called otoferlin, located in the inner ear hair cells. This protein enables sound signals to travel from the hair cells to the auditory nerve, which then sends the information to the brain.
However, when the OTOF gene does not function properly, the ear may appear structurally normal, but sound signals fail to reach the brain, resulting in deafness from birth.
Creation of Genetically Modified Marmosets
To investigate this condition more closely, researchers used the CRISPR/Cas9 gene-editing technology to precisely disable the OTOF gene in fertilized marmoset eggs.
After modifying the gene, the scientists implanted the embryos into a surrogate mother. The resulting offspring developed normally and remained healthy; however, they were completely deaf from birth.
Further tests confirmed the results. Researchers performed electrophysiological hearing tests, similar to an electroencephalogram (EEG), which demonstrated that the animals could not transmit sound signals to the brain. Additionally, laboratory analysis revealed the absence of otoferlin protein in the inner ear hair cells, confirming the successful gene knockout.
A Breakthrough for Hearing Loss Research
According to Tobias Moser, Director of the Institute of Auditory Neuroscience at the University Medical Center Göttingen, the new model represents a significant advancement for hearing research.
“With the OTOF-knockout marmosets, we now have, for the first time, a primate model that realistically replicates human OTOF-related hearing loss,” he said. “This gives researchers a crucial tool for developing therapies in a more targeted and safer way while also studying long-term effects.”
Bridging the Gap Between Laboratory Research and Human Treatment
Until now, scientists primarily relied on mouse models and cell cultures to study genetic hearing disorders. While useful, these models cannot fully replicate the complex hearing physiology found in humans.
As reported by medicalxpress, the newly developed marmoset model bridges this gap by offering conditions that more closely resemble human auditory development and function. As a result, researchers can conduct more accurate studies on inner ear therapies, gene treatments, and advanced hearing technologies.
Interdisciplinary Collaboration Drives the Discovery
Creating genetically modified primates requires highly specialized expertise. Rüdiger Behr, head of the Stem Cell Biology and Regeneration Platform at the German Primate Center, emphasized the complexity of the work.
He noted that combining reproductive biology, genome editing, biomedical science, and veterinary research made it possible to successfully create the genetically modified marmosets.
The project highlights the importance of interdisciplinary collaboration among leading scientific institutions.
Advancing Future Treatments for Hearing Disorders
The new primate model opens the door to developing and testing innovative treatments for hearing loss, including gene therapies and optogenetic cochlear implants.
According to Marcus Jeschke, professor at the German Primate Center and the University Medical Center Göttingen, the model represents a major step forward for translational medical research.
“This model offers the opportunity to test and optimize OTOF gene therapies and advanced cochlear implant technologies under conditions that are much closer to human hearing,” he explained.
Ultimately, the research could pave the way for new therapies to treat genetic deafness and other currently incurable hearing disorders, bringing hope to millions of people affected by congenital hearing loss.