Generation and Characterization of a Zebrafish Model for ADGRV1-Associated Retinal Dysfunction Using CRISPR/Cas9...

Area of Science:

• Genetics and Molecular Biology
• Ophthalmology
• Neuroscience

Background:

• Retinitis pigmentosa (RP) affects 40,000 people globally due to pathogenic variants in the ADGRV1 gene, with no current treatments.
• Developing a model organism is crucial for understanding ADGRV1-associated RP pathophysiology and testing therapies.
• CRISPR/Cas9 technology enables efficient generation of mutant models, and zebrafish are suitable for studying retinal dysfunction.

Purpose of the Study:

• To generate and characterize the first zebrafish model for ADGRV1-associated retinitis pigmentosa.
• To investigate the role of ADGRV1 in zebrafish photoreceptor function and USH2 complex member localization.
• To establish quantifiable outcome measures for evaluating future therapeutic strategies.

Main Methods:

• Utilized CRISPR/Cas9 genome editing to introduce a 4bp deletion in the adgrv1 gene exon 9 of zebrafish.
• Performed immunohistochemical analysis to assess Adgrv1 protein localization and USH2 complex member levels.
• Conducted electroretinogram (ERG) recordings to evaluate retinal function in adgrv1 mutant zebrafish.

Main Results:

• Adgrv1 protein was absent from the photoreceptor connecting cilium in the adgrv1 zebrafish retina.
• Absence of Adgrv1 led to reduced levels of usherin and Whrnb, suggesting interaction within the USH2 complex.
• Increased aberrant rhodopsin localization and decreased ERG B-wave amplitudes indicated impaired retinal function.

Conclusions:

• The adgrv1 zebrafish represents the first ADGRV1 mutant model exhibiting early retinal dysfunction.
• This model demonstrates Adgrv1's role in maintaining photoreceptor structure and function, potentially through interaction with the USH2 complex.
• The observed phenotypic changes provide quantifiable measures for assessing novel therapeutic strategies for ADGRV1-associated RP.