AAV-mediated base editing restores cochlear gap junction in GJB2 dominant-negative mutation-associated syndromic...

Area of Science:

• Genetics
• Molecular Biology
• Ophthalmology

Background:

• Gap junction β2 (GJB2) gene mutations, encoding connexin 26, are a primary cause of genetic deafness.
• These mutations lead to the degeneration of gap junction plaques (GJPs), disrupting intercellular communication.
• The R75W mutation in GJB2 causes syndromic hearing loss and palmoplantar keratoderma through GJP fragmentation.

Purpose of the Study:

• To investigate the potential of adenine base editor (ABE) technology for correcting the GJB2 R75W mutation.
• To evaluate the efficacy of an adeno-associated virus (AAV)-mediated base-editing strategy in a mouse model of GJB2-related hearing loss.

Main Methods:

• Development of an all-in-one AAV vector encoding a compact SaCas9-NNG-ABE8e and a sgRNA targeting the GJB2 R75W mutation.
• Application of the AAV vector in a transgenic mouse model harboring the GJB2 R75W mutation.
• Assessment of GJP structure and intercellular communication in cochlear supporting cells.

Main Results:

• The AAV-mediated base editing successfully corrected the pathogenic GJB2 R75W mutation.
• Restoration of the gap junction intercellular communication network and recovery of fragmented GJPs were observed.
• Fragmented GJPs in cochlear supporting cells were restored to orderly structures in treated mice.

Conclusions:

• ABE-based base editing is a promising therapeutic strategy for dominant GJB2-related hearing loss.
• This approach holds potential for treating GJB2-related skin diseases and other single-base substitution deafness mutations.
• Gene editing offers a novel avenue for addressing genetic disorders affecting hearing and skin.