Selection of viral capsids and promoters affects the efficacy of rescue of Tmprss3-deficient cochlea

Ksenia A Aaron; Katja Pekrun; Patrick J Atkinson; Sara E Billings; Julia M Abitbol; Ina A Lee; Yasmin Eltawil; Yuan-Siao Chen; Wuxing Dong; Rick F Nelson; Mark A Kay; Alan G Cheng

doi:10.1016/j.omtm.2023.08.004

Selection of viral capsids and promoters affects the efficacy of rescue of Tmprss3-deficient cochlea

Mol Ther Methods Clin Dev. 2023 Aug 11:30:413-428. doi: 10.1016/j.omtm.2023.08.004. eCollection 2023 Sep 14.

Authors

Ksenia A Aaron^{1

2}, Katja Pekrun^{3

4}, Patrick J Atkinson¹, Sara E Billings¹, Julia M Abitbol¹, Ina A Lee¹, Yasmin Eltawil¹, Yuan-Siao Chen⁵, Wuxing Dong¹, Rick F Nelson⁵, Mark A Kay^{3

4}, Alan G Cheng^{1

3}

Affiliations

¹ Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
² Head and Neck Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
³ Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94305, USA.
⁴ Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.
⁵ Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA.

Abstract

Adeno-associated virus (AAV)-mediated gene transfer has shown promise in rescuing mouse models of genetic hearing loss, but how viral capsid and promoter selection affects efficacy is poorly characterized. Here, we tested combinations of AAVs and promoters to deliver Tmprss3, mutations in which are associated with hearing loss in humans. Tmprss3^tm1/tm1 mice display severe cochlear hair cell degeneration, loss of auditory brainstem responses, and delayed loss of spiral ganglion neurons. Under the ubiquitous CAG promoter and AAV-KP1 capsid, Tmprss3 overexpression caused striking cytotoxicity in vitro and in vivo and failed to rescue degeneration or dysfunction of the Tmprss3^tm1/tm1 cochlea. Reducing the dosage or using AAV-DJ-CAG-Tmprss3 diminished cytotoxicity without rescue of the Tmprss3^tm1/tm1 cochlea. Finally, the combination of AAV-KP1 capsid and the EF1α promoter prevented cytotoxicity and reduced hair cell degeneration, loss of spiral ganglion neurons, and improved hearing thresholds in Tmprss3^tm1/tm1 mice. Together, our study illustrates toxicity of exogenous genes and factors governing rescue efficiency, and suggests that cochlear gene therapy likely requires precisely targeted transgene expression.

Keywords: Tmprss3; cochlea; gene therapy; hair cells; hearing loss; supporting cells.

Abstract

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