Gene Therapy for DFNA9 : downregulating the mutant COCH gene in mammalian cell lines by uising a synthetic adeno-associated viral vector Anc80L65 and CRISPR/Cas9-mediated genetic editing.

DNFA9 is a cause of autosomal dominant (AD) non-syndromic late-onset sensorineural hearing loss (SNHL) associated with progressive bilateral vestibular failure (BVF). The age of SNHL onset varies depending on the mutation though the average onset age lies around 3rd-5th decade. It typically starts as downsloping of the audiogram at the age of onset and evolution towards deafness. DFNA9 is caused by mutations in the COCH gene (Coagulation Factor C Homology), which is located on chromosome 14q12-13 and encodes for a 550 amino acid protein, cochlin, which is expressed throughout the inner ear in spindle-shaped cells located along nerve fibers between the spiral ganglion and sensory epithelium. Over twenty mutations have been identified in regions, including North America, Japan, Australia, Korea, China and Belgium/Netherlands.Our objective is to establish an in vitro proof-of-principle for a gene therapeutic approach that targets mutant cochlin expression in the inner ear using Anc80L65AAV/CRISPR/Cas9-mediated gene editing.We hope to establish in vitro that this technique enables specific correction or downregulation of the mutant COCH gene in mammalian cell lines without modulating the normal COCH allele, which is still present in this heterozygous disorder.This work can provide proof-of-concept for in vivo studies in transgenic heterozygous COCH mice targeting the mutated COCH gene by means of an AAV.

Keywords:BALANCE DISORDERS, HEARING LOSS, GENETIC DEAFNESS

Disciplines:Genetics, Systems biology, Molecular and cell biology