Presenting Author University of Utah Salt Lake City, Utah
Purpose: Very long-chain polyunsaturated fatty acids (VLC-PUFAs) are a distinct class of lipids with chain lengths greater than 24 carbons. ELOVL4 is a protein responsible for VLC-PUFA biosynthesis. However, in patients with autosomal dominant Stargardt 3 disease, the gene encoding ELOVL4 is mutated, and as a result, a dysfunctional, truncated protein is produced instead. It is unclear whether the disease phenotype is caused by truncated protein aggregates, the absence of VLC-PUFAs, or a combination of these factors. Moreover, homozygous elovl4 ablation is neonatal lethal in mice. This study aimed to delineate the effect of VLC-PUFA loss on photoreceptor function.
Methods: Elovl4b knockout zebrafish were generated by creating a deletion mutation in exon 2 of the elovl4b gene using CRISPR-Cas9. Mutant zebrafish were screened for non-specific mutations by outcrossing mutant adults with wild-type fish. Their eyes were isolated, total fatty acids extracted, and the quantity of VLC-PUFAs determined through gas chromatography and mass spectrometry.
Results: We found that homozygous Elovl4b mutant zebrafish eyes had altered lipid profiles and a significantly lower abundance of C30 to C34 VLC-PUFAs compared to age-matched wild-type controls. We also predict diminished a- and b-wave amplitudes from ERG recordings – indicative of a loss of photoreceptor function and a thinner outer nuclear layer than controls.
Conclusion: Our data indicate that the loss of Elovl4b in zebrafish can cause an ocular phenotype comparable to juvenile-onset macular degeneration. The availability of a homozygous animal model of ELOVL4 deficiency will also allow for further studies on other ELOVL4-related diseases.
Support or Funding Information
National Institutes of Health
Foundation Fighting Blindness
Research to Prevent Blindness
lt;pgt;National Institutes of Health lt;/pgt;lt;pgt;Foundation Fighting Blindness lt;/pgt;lt;pgt;Research to Prevent Blindnesslt;/pgt;
