Gene Therapy Development for Hearing Disorder

Hearing disorder is a partial or total inability to hear, mainly caused by the damage and the natural aging process of mechanosensory hair cells located within the inner ear. Currently, the most common option for the treatment of hearing disorder is hearing rehabilitation using hearing devices. Recent advances in developing gene therapy provide a promising treatment modality for genetic hearing loss. By overcoming the functional deficits created by the underlying genetic mutations or inducing hair cell differentiation into the cochlea, gene therapy can restore the hearing function. To increase efficiencies and accelerate the gene therapy products development process, Creative Biolabs offers a broad range of early development services, especially for the gene therapy strategy design, hair cell regeneration, and validation and function assessment in vitro and in vivo. Our services can be specially tailored to your project if you have any requirements.

Figure 1. Several routes of delivery for injecting gene therapy vectors into the inner ear (Ahmed 2017)

Gene Therapy Development Services for Hearing Disorder

• Gene Therapy for Genetic Hearing Loss

Genetic hearing loss is the most common inherited sensory disorders, which needs a hearing aid and cochlear implanting. Gene therapy for genetic hearing loss is aimed at replacing the nonfunctional gene products by delivering functional copies of the gene (e.g., cDNA) or silencing the mutated copy of the gene to restore normal function (e.g., RNA interference). The mutations of gap junction protein beta 2 (GJB2) gene are the most common causes of genetic hearing loss in humans and recent studies have shown that the delivery of normal copies of the Gjb2 gene mediated by AAV is able to reestablish intercellular gap junction network in the mutant mouse cochlea. With increasing knowledge of the genetics of hearing loss, gene therapy will be widely used in clinical application.

• Gene Therapy for Cochlear Hair Cell Regeneration

It has documented that sensorineural hearing loss generally results from degeneration of cochlear hair cells. Therefore, an alternative approach to hearing disorders therapy can induce hair cell regeneration by delivering genes that are critical to hair cell differentiation into the cochlea. Some groups have found that the viral vector overexpressing Atoh1, a gene that is critical for hair cell differentiation, is  delivered into the deafened cochleae via the cochleostomy approach, leading to hair cells regeneration and improving the auditory brainstem response (ABR) threshold. Atoh1 gene therapy is a promising pathway of providing cochlear hair cells protection and inducing the cells regeneration. In addition, gene therapies using miRNAs can also induce hair cell regeneration. Such as the overexpression of miR181a can stimulate hair cell proliferation in the chick basilar papilla.

• Gene Therapy for Hearing Preservation

Another gene therapy strategy for hearing loss is to deliver genes that can protect against hair cells or neuronal loss. In previous studies, an AAV vector encoding brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT3) have been delivered into the drug-deafened guinea pigs. The results show that cochleas treated with BDNF and NT3 gene therapy have higher spiral ganglion neuron survival than untreated group. Therefore, gene therapy with protective gene or factors that promote cell survival can be used to prevent the cell death in the cochlea.

As a CRO specializing in gene therapy, Creative Biolabs has established the world-leading platforms to serve worldwide clients and enable you to free up your time for core work and project. For more information in our services, please feel free to contact us to discuss your specific requirements.

Reference

1. Chien, W., Monzack, E., McDougald, D. and Cunningham, L. (2015). Gene Therapy for Sensorineural Hearing Loss. Ear and Hearing, 36(1), pp.1-7.
2. Ahmed, H., Shubina-Oleinik, O. and Holt, J. (2017). Emerging Gene Therapies for Genetic Hearing Loss. Journal of the Association for Research in Otolaryngology, 18(5), pp.649-670.
3. Lee, M. and Park, Y. (2018). Potential of Gene and Cell Therapy for Inner Ear Hair Cells. BioMed Research International, 2018, pp.1-11.