Figure 1.

Overview of Therapeutic Concepts, Experimental Timeline, Progression of Hearing Loss, and Underlying Cochlear Morphology in Tmc1^Bth/+ Mice

Cochlear transgene delivery in Tmc1^Bth/+ mice shows robust transduction of IHCs. (A) Click-evoked ABR thresholds in wild-type and Tmc1^Bth/+ mice from 4 to 20 weeks with representative IHC images of scanning electron microscopy and immunohistochemistry at the indicated time points. Arrows indicate IHC loss; disorganized and fused stereocilia bundles increase over time on scanning electron microscopy. (B) Schematic overview with and without RNAi-mediated gene silencing in Tmc1^Bth/+ mice. (C) Transgene constructs. Dual-promoter viral insert with the U6 promoter driving miTmc miRNA or miSafe and the CMV promoter driving EGFP. (D) Experimental timeline with delivery of miRNAs at three different time points (P15–P16, P56–P60, and P84–P90). Outcomes followed by ABR, immunohistochemistry, and scanning electron microscopy. (E) Cochleae harvested 14 days after AAV9.miTmc1 RWM+CF injection in 2-week-old Tmc1^Bth/+ mice. Representative low-magnification images of whole-mount apical turns and high-magnification images of regions along the cochlea duct 0.8–1.2 mm (apex), 2.2–2.6 mm (middle), and 3.8–4.2 mm (base) from the apical tip.