Abstract
Very-long-chain PUFAs (VLC-PUFAs) are a group of lipids with chain lengths >24 carbons, and the ELOVL4 (elongation of very-long-chain FA-4) enzyme is responsible for vertebrate VLC-PUFA biosynthesis. Studies on the role of VLC-PUFAs in vision have been hindered because of the need for adequate animal models to capture the global loss of VLC-PUFAs. Since homozygous Elovl4 ablation is lethal in neonatal mice because of catastrophic drying from the loss of their protective skin barrier, we established a zebrafish (Danio rerio) model of Elovl4 ablation. We generated Elovl4b KO zebrafish by creating a 56-bp deletion mutation in exon 2 of the Elovl4b gene using CRISPR-Cas9. We used GC-MS and LC-MS/MS to analyze the VLC-PUFA and lipid profiles from wild-type and Elovl4b KO fish eyes. We also performed histology and visual-behavioral tests. We found that heterozygous and homozygous Elovl4b KO zebrafish eyes had altered lipid profiles and a significantly lower C30 to C36 VLC-PUFA abundance than wild-type fish. Moreover, Elovl4b and Elovl4b-/- KO larvae had significantly lower motor activity in response to light-dark cycles than their age-matched controls. Elovl4b-/- adult fish showed no obvious differences in gross retinal morphology and lamination compared with wild type, except for the presence of lipid droplets within the retinal pigment epithelial cell layer of Elovl4b-/- fish. Our data indicate that the loss of Elovl4b in zebrafish changes ocular lipid profiles and leads to visual abnormalities and subtle retinal changes. These findings highlight the use of zebrafish as a model for VLC-PUFA depletion and ELOVL4-related dysfunction.
| Original language | English (US) |
|---|---|
| Article number | 100518 |
| Journal | Journal of lipid research |
| Volume | 65 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 2024 |
Funding
The authors acknowledge the Centralized Zebrafish Animal Resource at the University of Utah for providing zebrafish husbandry, laboratory space, and equipment to carry out portions of this research. Lipidomic analysis was performed at the Metabolomics Core Facility at the University of Utah. Mass spectrometry equipment was obtained through NCRR Shared Instrumentation grants 1S10OD016232-01, 1S10OD018210-01A1, and 1S10OD021505-01. The authors thank Dan Cuthbertson of Agilent Technologies for assistance in implementing iterative exclusion in the tandem mass spectrometry experiments. Sequencing was performed at the DNA Sequencing Core Facility, and imaging with the Zeiss AxioScan slide scanner was performed at the Health Sciences Center Cell Imaging Core, University of Utah. This work was supported by the National Institutes of Health grants EY034497 and EY014800, the Foundation for Fighting Blindness, and an unrestricted grant from Research to Prevent Blindness, New York, NY, to the Department of Ophthalmology and Visual Sciences, University of Utah.
Keywords
- ELOVL4
- lipids
- retinal degeneration
- verylong- chain PUFAs
- zebrafish
ASJC Scopus subject areas
- Biochemistry
- Endocrinology
- Cell Biology