Understanding Harmful Algal Blooms & Neurotoxicity

Advancements in aquatic toxicology and developmental neuroscience have broadened understanding of harmful algal blooms (HABs) and their impact on aquatic ecosystems and human health. In the article "Domoic acid induces developmental stage-specific effects on microglia in zebrafish," published in the journal Harmful Algae, Exponent's Jordan Pitt and co-authors examined the effects of the neurotoxin domoic acid (DA) on microglial cells in zebrafish. Their study addresses a critical knowledge gap regarding the impact of DA on non-neuronal cells during sensitive developmental periods, a topic of growing concern as HABs become more frequent due to climate change and eutrophication.

Researchers found that DA exposure in zebrafish affects microglial cells differently depending on age and dose. The study showed that low DA levels at early stages changed microglial structure without visible defects, while higher doses in older larvae caused clear abnormalities. The findings suggest that microglial reactivity and neuroinflammation may arise at lower DA exposures than previously recognized.

This investigation provides new insights into the effects of HABs and the cellular mechanisms underlying DA neurotoxicity, highlighting the importance of developmental timing in toxicological outcomes. The authors emphasize the need for further research into the consequences of low-dose DA exposure and its impact on microglial function, recommending continued development of sensitive models and assays to better characterize environmental neurotoxin effects in developing organisms.

From the publication: "Our results revealed significant developmental stage-specific differences in sensitivity to DA. Notably, the incidence of gross morphological defects, alterations in microglial abundance, and changes in microglial morphology varied between larvae exposed to DA at 2 dpf and those exposed at 4 dpf."