Effects of SaCas9-KKH+sgRNA4.2 on inner ear function in Bth mice. (a) Representative sensory transduction currents recorded at P14-16 from apical IHCs and OHC of uninjected Tmc1Bth/Δ;Tmc2Δ/Δ mice (left) and those injected with AAV-SaCas9-KKH-sgRNA4.2 at P1-P2 (right). (b) Mean ± SEM maximal current amplitudes, measured at P14-16 for uninjected IHCs (n = 19; top) and OHCs (n = 10; bottom) from uninjected Tmc1Bth/Δ; Tmc2
Δ/Δ (red) and injected (black) mice. (IHCs: 124 ± 118 pA, n = 7, p = 3.4×10−6; OHCs: 71 ± 41 pA, n = 12, p = 8.1×10−7; unpaired two-tailed t-test). (c) Families of ABR waveforms recorded at eight weeks from an uninjected Tmc1Bth/WT mouse (left) and a Tmc1Bth/WT mouse injected with AAV-SaCas9-KKH-gRNA-4.2 at P1 (right). Bolded traces indicate threshold. Scale bar applies to all traces. (d) ABR thresholds plotted as a function of frequency for ten injected Tmc1Bth/WT mice (green). Mean ± S.D. ABR thresholds for uninjected Tmc1Bth/WT (red, n = 8), and uninjected Tmc1WT/WT control mice (black) tested at 4 (n = 6), 8 (n = 12) and 12 (n = 12) weeks. (e) DPOAE thresholds verses stimulus frequency at 12 weeks for eight injected Tmc1Bth/WT mice (green). Mean ± S.D. DPOAE thresholds for uninjected Tmc1Bth/WT (red, n = 9), and uninjected Tmc1WT/WT control mice (black, n = 13). (f) Mean ± S.D. ABR thresholds at 8 kHz verses age, from 4 to 40 weeks (WT: n = 6, 12, 12, 6; Tmc1Bth/WT: n = 8, 8, 9, 9, 6; +SaCas9-KKH: n = 8, 7, 7, 4, 4; one-way ANOVA, p = 0.32). (g) Representative confocal images of 100-μm cochlear sections harvested at 24 weeks from 8, 16, and 32 kHz regions of four uninjected (top), and six injected Tmc1Bth/WT mice (bottom). Tissue was stained for MYO7A (red) and actin (green). (h) Mean ± S.D. number of IHCs (left) and OHCs (right) per 100-μm section for four uninjected and six injected Tmc1Bth/WT mice (i) SEM images of the apical cochlear sensory epithelium showing hair bundle morphology for one uninjected Tmc1WT/WT (left), one uninjected Tmc1Bth/WT (middle), and one injected Tmc1Bth/WT mouse (right).