Spatially resolved lipid disruption induced in Daphnia magna by environmentally relevant exposure to obesogens tributyltin and pyriproxyfen.

Abstract

Environmental pollutants, particularly endocrine disruptors, are known to significantly dysregulate lipid homeostasis, causing severe health issues. However, their obesogenic effects on invertebrate species, such as the planktonic crustacean Daphnia magna, remain poorly understood. Previous research suggested that compounds such as organotin tributyltin and the insecticide pyriproxyfen promote lipid accumulation, particularly triacylglycerol species. However, bulk LC-MS methodologies used did not retain the spatial context of the biomolecules analyzed, failing in providing crucial insights into the tissue-specific molecular effects of pollutant exposure and risk assessment. The present study evaluates the disruptive effects of these compounds at the lipidomic level using a novel spatial MALDI-MSI-based approach integrated with ion mobility. In terms of toxicological assessment, MALDI-MSI revealed distinct lipidomic disruptions. Both pollutants increased glycerolipids, but glycerophospholipids exhibited opposing patterns. Tributyltin significantly altered the lipid composition of the nervous system, whereas pyriproxyfen predominantly affected the cardiovascular system. In conclusion, the integration of MALDI-MSI with ion mobility not only enhanced the identification of lipids but also allowed to provide deeper insights into the tissue-specific toxicological mechanisms of environmental obesogens in Daphnia magna. Additionally, this study emphasizes the potential of these state-of-the-art analytical techniques in advancing spatial biology and environmental risk assessment.