| Autor: |
Aben, F., Verdoodt, D., de Bruijn, S., Oostrik, J., Venselaar, H., Sels, L., De Backer, E., Gommeren, H., Szewczyk, K., Van Camp, G., Ponsaerts, P., Van Rompaey, V., van Wijk, E., de Vrieze, E. |
| Předmět: |
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| Zdroj: |
Journal of Hearing Science; Sep2024, Vol. 14 Issue 3, p100-101, 2p |
| Abstrakt: |
The c.151C>T (p.P51S) mutation in COCH is highly prevalent in the Dutch/Belgian population and causes DFNA9 (hearing loss and vestibular dysfunction) in > 1500 individuals. The initial symptoms manifest between the 3rd and 5th decade of life, which leaves ample time for therapeutic intervention. The clear non-haploinsufficiency disease mechanism indicates that blocking or reducing the p.P51S mutant cochlin protein levels may alleviate or prevent the DFNA9 phenotypes. Considering the broad expression of COCH by the fibrocytes of the inner ear, we designed "gapmer" antisense oligonucleotides (ASO) to specifically induce RNase H1-mediated degradation of COCH transcripts containing the c.151C>T mutation. We established several model systems to investigate the molecular efficacy of ASOs targeting the c. 151C>T mutation or low-frequency mutant allele-specific SNPs. Using overexpression models, we identified several ASOs that efficiently induce the degradation of mutant COCH transcripts. By introducing chemical modification to the oligonucleotide bases, we can alter the affinity and selectivity for the mutation transcript. We identified several ASOs with a strong preference for the mutant transcript in overexpression models. To investigate allele-specificity under physiological expression levels, we exposed patient-derived otic progenitor cells (iPCS-OPCs) to different ASOs for 8 days. In parallel, we developed a genetically humanized mouse model for DFNA9 in which human sequence-specific therapeutic strategies can be evaluated. Phenotypic follow-up of mice of all genotypes indicate that the genetic humanization has no adverse effects, and removal of the Cdh23ahl allele is mandatory to observe the late-onset auditory phenotype: the first signs of high-frequency hearing loss emerged at 12 months of age. Studies in iPSC-OPCs indicated that the ASOs identified in overexpression studies also effectively reduce mutant COCH transcript levels in patient-derived cells with physiological expression levels. Unfortunately, variation between replicate wells of OPC differentiation is relatively high, making it difficult to draw conclusions on allele-specificity. We selected a candidate ASO, directed against a rare mutant allele-spe-cific intronic SNP, for subsequent studies in our humanized mouse model. First intracochlear injections will be conducted in May 2024, after which we can collect the first in vivo data on gapmer ASO uptake and efficacy in fibrocytes of the mammalian inner ear. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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