(P25-031-24) Creation of a Novel Zebrafish Model With Altered Omega-3 Fatty Acid Status to Study the Role of Maternal Nutrition During Neurodevelopment

Objectives: Docosahexaenoic acid (DHA), a dietary omega-3 fatty acid, is a major building block of cell membrane phospholipids in the brain. Offspring rely on maternal DHA transfer to meet their neurodevelopmental needs, but most Americans do not meet DHA intake guidelines. Low DHA status is linked to impaired immune responses, white matter defects, and an increased risk of psychiatric disorders. However, the underlying cellular mechanisms involved are unknown, and advancements in the field have been limited by the existing tools and animal models. Zebrafish are an excellent model for studying neurodevelopmental mechanisms; embryos undergo rapid external development and are optically transparent, enabling direct observation of individual cells and dynamic cell-cell interactions in a way that is not possible in rodents.

Methods: We created a zebrafish model with low DHA status by 1) disrupting elovl2, a rate-limiting gene in the DHA biosynthesis pathway, via CRISPR-Cas9 mutagenesis and 2) feeding mothers a diet containing omega-3 precursors but no preformed DHA for 5 months. As a preliminary readout of offspring status, DHA-containing phospholipid species (DHA-PL) were profiled via LC-MS in pooled larvae at 4 days post fertilization (n=3 pools/group). Total fatty acid analyses are also underway as an indicator of overall body DHA status.

Results: Wild-type mothers fed DHA-deficient diet produced offspring with 44% lower DHA-PL than the DHA-sufficient reference group (76.5±17.5 vs 43.2±9.7 pmol/pool; P=0.06). Feeding elovl2^+/- mothers DHA-deficient diet reduced offspring DHA-PL by 55% (76.5±17.5 vs 34.5±5.0 pmol/pool; P < 0.01). DHA-PL were similar between elovl2^+/+ and elovl2^-/- siblings (34.1±6.9 vs 34.9±7.4 pmol/pool; P=0.72).

Conclusions: By combining dietary restriction and genetic disruption at the maternal level, we generated offspring with altered DHA status. We are using this novel zebrafish model to investigate whether DHA depletion during development alters the response and functions of microglia, the brain’s resident macrophages. This work could reveal a cellular mechanism by which low DHA status leads to neurodevelopmental abnormalities and provide insight into maternal nutritional strategies that optimize infant brain health.

Funding Sources: NIH/NINDS F32 (KMR); Colorado NORC Pilot Grant (KMR); NIH/NINDS R35 (BA)