Zebrafish Cyp1b1 knockout alters eye and brain metabolomic profiles, affecting ocular and neurobehavioral function

Abstract

Cytochrome P450 1B1 (CYP1B1) metabolizes endogenous and xenobiotic substrates, including steroids and fatty acids. It is implicated in the metabolism of compounds essential for eye development and is a causative gene in primary congenital glaucoma (PCG). However, CYP1B1's role in PCG and related eye disorders and neurobehavioral function is poorly understood. To investigate the role of Cyp1b1 this study used a novel CRISPR-Cas9 generated Cyp1b1 mutant zebrafish (Danio rerio) line. Behavioral, metabolomic, and transcriptomic analyses were performed to determine the molecular and behavioral consequences of the mutant Cyp1b1. Further we aimed to distinguish a visual defect from other neurological effects. Larval mutant zebrafish were hyperactive during the vision-based larval photomotor response assay but behaved normally in the sound-based larval startle response assay. Adult mutants exhibited normal locomotion but altered interactions with other fish. In vision and hearing-based assays, mutant fish showed altered behavior to visual stimuli and reduced auditory responses. Mass spectrometry-based metabolomics analysis revealed 26 differentially abundant metabolites in the eye and 49 in the brain between the genotypes, with perturbed KEGG pathways related to lipid, nucleotide, and amino acid metabolism. RNA sequencing identified 95 differentially expressed genes in the eye and 45 in the brain. Changes in arachidonic and retinoic acid abundance were observed and potentially modulated by altered expression of CYP 1, 2, and 3 family enzymes. While these findings could not point to specific ocular defects over other neurobehavioral phenotypes, behavioral assays and omics analyses highlighted the role of Cyp1b1 in maintaining metabolic homeostasis and the behavioral consequences due to its loss.