Project description:Hearing loss is one of the most prevalent sensory disorders, but no commercial biological treatments are currently available. Here, we identify an East Asia-specific founder mutation, the homozygous c.220C>T mutation in MPZL2, that contributes to a significant proportion of hereditary deafness cases in our cohort study. We find that the disease-causing mutation can be targetable by adenine base editors (ABEs) that enable A·T-to-G·C base corrections without DNA double-strand breaks. To demonstrate this, we develop a humanized mouse model (hMPZL2Q74X/Q74X) that recapitulates human MPZL2 deafness and leads to progressive hearing loss. A PAM-flexible ABE variant with reduced bystander and off-target effects (ABE8eWQ-SpRY:sgRNA3) is packaged in dual adeno-associated viruses (AAVs) and injected into the inner ear of hMPZL2Q74X/Q74X mice and effectively corrects the mutation. This treatment significantly restores hearing function, improves inner ear structural integrity, and reverses altered gene expression. Base editing may hold therapeutic potential for hereditary deafness, including most cases of MPZL2 deafness.
Project description:Deafness is the most common form of sensory impairment in humans and frequently caused by defects in hair cells of the inner ear. Here we demonstrate that in a mouse model for recessive non-syndromic deafness (DFNB6), inactivation of Tmie in hair cells disrupts gene expression in the neurons that innervate them. This includes genes regulating axonal pathfinding and synaptogenesis, two processes that are disrupted in the inner ear of the mutant mice. Similar defects are observed in mouse models for deafness caused by mutations in other genes with primary functions in hair cells. Gene therapy targeting hair cells restores hearing and inner ear circuitry in DFNB6 model mice. We conclude that hair cell function is crucial for the establishment of peripheral auditory circuitry. Treatment modalities for deafness thus need to consider restoration of the function of both hair cells and neurons, even when the primary defect occurs in hair cells.
2024-11-10 | GSE281207 | GEO
Project description:In vivo postnatal base editing rescues hearing in a mouse model of recessive deafness
| PRJNA578156 | ENA
Project description:Optimized precise base editing restores normal hearing in adult DFNB9 mice
Project description:The mammalian inner ear subserves auditory and vestibular sensations via highly specialized cells and proteins. We show that sensory hair cells (HCs) employ hundreds of uniquely or highly expressed proteins for processes involved in transducing mechanical inputs, stimulating sensory neurons, and maintaining structure and function of these post-mitotic cells. Our proteomic analysis of purified HCs extends the existing HC transcriptome, revealing undetected gene products and isoform-specific protein expression. Comparison with mouse and human databases of genetic auditory/vestibular impairments confirms the critical role of the HC proteome for normal inner ear function, providing a cell-specific pool of candidates for novel, important HC genes. Several proteins identified exclusively in HCs by proteomics and by immunohistochemistry map to human genetic deafness loci, potentially representing new deafness genes.
2016-05-23 | MSV000079756 | MassIVE
Project description:In vivo adenine base editing in an adult mouse model of tyrosinemia
| PRJNA513076 | ENA
Project description:In vivo Adenine Base Editing rescues adrenoleukodystrophy in a humanized mouse model
Project description:We collected single cell transcriptome profiles of inner ear organoids from passage 2 (day 8) in expansion medium, differentiated day 5, and differentiated day 25. Cells from the three time points were divided into 5 distinct clusters by UMAP, indicating the presence of the basic cell types of the organ of Corti in cochlear organoid model. Deafness-related gene expression in differentiated day 25 organoid showed that the cell-type specificity related to genetic auditory disease was preserved in the organoids, and dynamic gene expression changes were observed along lineage trajectories form progenitors to mature cell types, similar to in vivo developmental process. These results showed that cochlea organoid can be used as a useful model for deciphering the effects of deafness gene mutations and understanding inner ear development.