Postnatal Slc26a4 gene therapy improves hearing and structural integrity in a hereditary hearing loss model
Yi-Hsiu Tsai, Peng-Yu Wu, Yu-Chi Chuang, Chun-Ying Huang, Hiroki Takeda, Hiroshi Hibino, Chen-Chi Wu, Yen-Fu Cheng
Yi-Hsiu Tsai, Peng-Yu Wu, Yu-Chi Chuang, Chun-Ying Huang, Hiroki Takeda, Hiroshi Hibino, Chen-Chi Wu, Yen-Fu Cheng
View: Text | PDF
Research Article Genetics Otology

Postnatal Slc26a4 gene therapy improves hearing and structural integrity in a hereditary hearing loss model

Abstract

Mutations in SLC26A4 are the second most common cause of hereditary hearing loss (HL) in many Asian countries, leading to DFNB4, a condition characterized by progressive HL and inner ear malformations. While gene therapy holds great potential, its postnatal application has remained unexplored because of the lack of suitable animal models and the challenges of prenatal intervention. To our knowledge, this study represents the first preclinical investigation of postnatal gene therapy for DFNB4 using a clinically relevant Slc26a4-mutant mouse model that closely replicates human auditory phenotypes. Utilizing the synthetic AAV.Anc80L65 vector, we achieved robust SLC26A4 delivery to critical cochlear regions, including the endolymphatic sac and cochlear lateral wall. Comprehensive phenotypic analyses revealed a critical therapeutic window spanning the neonatal and juvenile stages, within which AAV.Anc80L65-mediated SLC26A4 delivery significantly improved hearing, as evidenced by lower auditory brainstem response thresholds. Moreover, the therapy preserved hair cells, reduced endolymphatic sac enlargement, partially restored the endocochlear potential, and mitigated inner ear structural degeneration. These therapeutic effects persisted into adulthood, highlighting the long-term efficacy of postnatal gene therapy. Together, these findings establish a critical therapeutic window for DFNB4 and demonstrate the feasibility of targeting the endolymphatic sac and cochlear lateral wall for effective intervention.

Authors

Yi-Hsiu Tsai, Peng-Yu Wu, Yu-Chi Chuang, Chun-Ying Huang, Hiroki Takeda, Hiroshi Hibino, Chen-Chi Wu, Yen-Fu Cheng

×

Figure 3

Neonatal delivery of Anc80.hSLC26A4 improves hearing improvement and preserves cochlear structure in L236P-mutant mice.

Options: View larger image (or click on image) Download as PowerPoint
Neonatal delivery of Anc80.hSLC26A4 improves hearing improvement and pre...
(A) Experimental timeline of neonatal delivery of Anc80.hSLC26A4 to L236P-mutant mice. The illustration is created with BioRender.com. (B) Representative ABR waveforms for P30 L236P-mutant mice receiving a vehicle (left panel, threshold at 90 dB SPL in 32 kHz) or Anc80.hSLC26A4 (middle panel, threshold at 35 dB SPL in 32 kHz) injection as neonates. Age-matched WT FVB mice were used as a control (right panel, threshold at 35 dB SPL in 32 kHz). (C) ABR thresholds of vehicle-treated (black lines) and Anc80.hSLC26A4-treated (dark blue lines; individual mice are represented by light blue lines) L236P-mutant mice. Age-matched WT FVB mice are represented by gray lines. Data are presented as the mean ± SD (n = 13–23 mice in each group). *P < 0.05, ** P < 0.01, and *** P < 0.001, by Kruskal-Wallis test with Dunn’s test. (D) Hair cell morphology at the cochlear basal turn in vehicle- and AAV-treated mice at P30 and P150. The green, red, and blue channels represent myosin VIIA, phalloidin, and DAPI, respectively. Scale bars: 100 μm. (E and F) Quantification of basal IHCs (E) and OHCs (F). Data are presented as mean ± SD. ***P = 0.004, by Mann-Whitney U test. (G) Morphology of marginal cells in the basal turn stria vascularis. Phalloidin staining (red) was used to delineate cell boundaries and epithelial organization. White arrows indicate atrophic marginal cells. Scale bars: 50 μm. (H) Quantification of the surface area of marginal cells. Data are presented as the mean ± SD. *P = 0.05 and ** P = 0.001, by ordinary 2-way ANOVA with Tukey’s multiple-comparison test. (I) EP value for vehicle-treated (n = 7) and AAV-treated L236P (n = 10) mice at P30. Data are presented as the mean ± SD. *P = 0.01, by unpaired, 2-tailed t test.