Mini-PCDH15 gene therapy rescues hearing in a mouse model of Usher syndrome type 1F
Maryna V. Ivanchenko, Daniel M. Hathaway, Alex J. Klein, Bifeng Pan, Olga Strelkova, Pedro De‐la‐Torre, Xudong Wu, Cole W. Peters, Eric M. Mulhall, Kevin T. Booth, Corey Goldstein, Joseph Brower, Marcos Sotomayor, Artur A. Indzhykulian, David P. Corey
Abstract
Usher syndrome type 1 F (USH1F), caused by mutations in the protocadherin-15 gene (PCDH15), is characterized by congenital deafness, lack of balance, and progressive blindness. In hair cells, the receptor cells of the inner ear, PCDH15 is a component of tip links, fine filaments which pull open mechanosensory transduction channels. A simple gene addition therapy for USH1F is challenging because the PCDH15 coding sequence is too large for adeno-associated virus (AAV) vectors. We use rational, structure-based design to engineer mini-PCDH15s in which 3-5 of the 11 extracellular cadherin repeats are deleted, but which still bind a partner protein. Some mini-PCDH15s can fit in an AAV. An AAV encoding one of these, injected into the inner ears of mouse models of USH1F, produces a mini-PCDH15 which properly forms tip links, prevents the degeneration of hair cell bundles, and rescues hearing. Mini-PCDH15s may be a useful therapy for the deafness of USH1F.