Extended time frame for restoring inner ear function through gene therapy in Usher1G preclinical model

Area of Science:

• Otolaryngology
• Genetics
• Developmental Biology

Background:

• Usher syndrome type 1 (USH1) is a leading genetic cause of congenital deafness, blindness, and vestibular dysfunction.
• Current neonatal gene therapy models for USH1 face challenges due to differing hearing onset times between mice and humans.
• USh1G is a significant subtype of USH1, necessitating research into extended therapeutic timelines.

Purpose of the Study:

• To investigate the efficacy of gene therapy for USH1G beyond the neonatal period in a mouse model.
• To determine if the therapeutic time window for USH1G gene therapy can be extended to align with human neonatal intervention stages.
• To assess the restoration of inner ear structure, hearing, and vestibular function following delayed gene therapy.

Main Methods:

• Gene therapy was administered to Ush1g-/- mice after the typical hearing onset.
• Inner ear hair cell structure was analyzed using confocal imaging and electron microscopy.
• Auditory brainstem response, vestibulo-ocular reflex, and locomotor tests were used to evaluate functional recovery.

Main Results:

• Gene therapy significantly restored hearing and vestibular function in Ush1g-/- mice up to postnatal day 21 (P21).
• Beyond P21 and up to P30, vestibular function recovery was observed, but hearing restoration was not significant.
• These findings demonstrate successful gene therapy intervention in USH1G mice at later developmental stages.

Conclusions:

• Gene therapy for USH1G is effective beyond the neonatal stage in mice, suggesting a potentially broader therapeutic window.
• The extended therapeutic window implies that USH1G gene therapy could be applicable to newborn humans.
• Further research is warranted to confirm the translatability of these findings to clinical applications for Usher syndrome type 1G.