What they found
TL;DR (qwen3.6:35b): This study demonstrates that the absence of Oncomodulin (OCM) significantly accelerates hearing loss in mice carrying the Cdh23753G→A mutation, causing functional decline by three months compared to twelve months in mice without the mutation. Additionally, OCM-deficient outer hair cells show greater structural deterioration and functional loss when exposed to ototoxic stress from HPβCD.
Oncomodulin (OCM) is the most abundant Ca2+ buffering protein found in mature outer hair cells (OHCs). Cadherin 23 (CDH23) is a crucial component of the tip-links in hair cell stereocilia. The absence or dysfunction of these two proteins contributes to the early onset of age-related hearing loss (AHL). In this study, we investigated the effects of the Cdh23753G→A mutation on OHC function using new Ocm-knockout (KO) mouse models (Ocmtm1a/tm1a) with or without the Cdh23753G→A mutation. Despite having the same genetic background, Ocm-KO mice carrying the Cdh23753G→A mutation displayed a notable decline in OHC function across all measured frequencies as early as three months of age. In contrast, Ocm-KO mice without the Cdh23753G→A mutation did not exhibit comparable hearing loss until they reached twelve months of age. Additionally, we examined the role of OCM in preserving OHC function under ototoxic stress induced by HPβCD (2-hydroxypropyl-β-cyclodextrin). The distortion product otoacoustic emission data show that the administration of HPβCD resulted in a more pronounced decline in OHC function in Ocm-KO mice compared to wild-type (WT) mice. Time-lapse recording also shows that HPβCD treatment led to greater structural deterioration and more rapid rupture events in OHCs from Ocm-KO mice than in those from WT mice. These findings suggest that the Cdh23753G→A mutation, rather than other potential strain-specific genetic factors associated with AHL, significantly exacerbates the early onset of AHL phenotypes in Ocm-KO mice. Furthermore, our data indicates that the OCM protein in OHCs enhances their ability to withstand ototoxic stimuli.
How this applies to our program
This research highlights the critical role of calcium buffering and tip-link integrity in hair cell survival, which is directly relevant to understanding the mechanotransduction defects and fragility associated with STRC/DFNB16 mutations. It suggests that preserving hair cell resilience against stressors may be a viable therapeutic strategy for STRC-related hearing loss.
Key numbers
- 3 months: Age of notable OHC function decline in Ocm-KO mice with the Cdh23753G→A mutation
- 12 months: Age of hearing loss onset in Ocm-KO mice without the Cdh23753G→A mutation
- HPβCD: The ototoxic agent used to induce stress and demonstrate reduced structural resilience in Ocm-KO mice
Links
Connections
[source]auto-indexed 2026-05-14 by strc-lit-watch