Increased proteasomal activity supports photoreceptor survival in inherited retinal degeneration

Area of Science:

• Ophthalmology
• Molecular Biology
• Genetics

Background:

• Inherited retinal degenerations affect over 2 million people globally, caused by mutations in more than 200 genes.
• A common pathological pathway involves impaired ubiquitin-proteasome system function in photoreceptor cells, leading to protein processing issues.
• Mutation-independent therapeutic strategies are needed to address the diverse genetic causes of these conditions.

Purpose of the Study:

• To investigate the potential of enhancing photoreceptor proteasomal activity as a therapeutic strategy for inherited retinal degenerations.
• To determine if increasing proteasome function can delay retinal degeneration.
• To evaluate the efficacy of overexpressing the 11S proteasome cap subunit, PA28α, in a mouse model.

Main Methods:

• Utilized a mouse model of inherited retinal degeneration.
• Overexpressed the 11S proteasome cap subunit, PA28α, in photoreceptor cells.
• Assessed the impact on proteasomal activity and photoreceptor survival, particularly in mice with the P23H rhodopsin mutation.

Main Results:

• Increasing photoreceptor proteasomal activity significantly delayed retinal degeneration in mice.
• Overexpression of PA28α enhanced ubiquitin-independent protein degradation in photoreceptors.
• Mice with the P23H rhodopsin mutation showed a quadrupled increase in surviving photoreceptors when treated with this strategy.

Conclusions:

• Proteasomes represent an attractive therapeutic target for inherited blindness.
• Enhancing proteasomal activity, specifically via PA28α, offers a potent mutation-independent approach to combat inherited retinal degenerations.
• This strategy holds significant promise for preserving vision in patients with various forms of inherited blindness.