PIKfyve preserves endolysosomal function in photoreceptors and RPE cells to maintain retinal integrity

Area of Science:

• Ophthalmology
• Cell Biology
• Biochemistry

Background:

• Photoreceptors require efficient clearance of cellular waste and mislocalized proteins for vision.
• Mechanisms for photoreceptor protein degradation are not fully understood.
• Retinal pigment epithelial (RPE) cells clear shed photoreceptor outer segments via phagocytosis.

Purpose of the Study:

• To investigate the role of PIKfyve, a lipid kinase, in retinal degradative and metabolic pathways.
• To determine the impact of PIKfyve deficiency on photoreceptor and RPE cell function and integrity.
• To explore the therapeutic potential of modulating PIKfyve activity in retinal degenerative diseases.

Main Methods:

• Selective deletion of PIKfyve in mouse models.
• Analysis of retinal structure and function (histology, electroretinography).
• Assessment of lysosomal markers, protein turnover, and metabolic balance in photoreceptors and RPE cells.
• Studies in P23H rhodopsin mutant mice to evaluate synergistic effects.

Main Results:

• PIKfyve deletion in photoreceptors caused progressive retinal degeneration, vacuolation, and functional decline.
• PIKfyve deficiency in RPE cells impaired phagocytosis and autophagy, leading to protein and lipid accumulation.
• Reduced PIKfyve accelerated degeneration in P23H rhodopsin mutant mice.
• PIKfyve is crucial for lysosomal function, protein turnover, and metabolic stability in the retina.

Conclusions:

• PIKfyve is essential for maintaining photoreceptor and RPE integrity.
• PIKfyve supports critical cellular processes including lysosomal function and protein degradation.
• Targeting PIKfyve may offer therapeutic benefits for retinal degenerative diseases, but requires careful consideration of potential side effects.