Integrated multi-omic profiling uncovers endocannabinoid system as a driver of nerve agent-induced cognitive dysfunction in guinea pigs

Soman, a highly lethal organophosphorus compound (OP), is notorious for its rapid induction of irreversible acetylcholinesterase binding through accelerated aging. Although subacute soman exposure has been specifically implicated in cognitive deficits, the molecular pathways driving these impairments remain poorly characterized, highlighting a significant research gap. This study aims to comprehensively elucidate the effects of soman exposure on cognitive impairment by analyzing proteome and lipidome alterations in the hippocampal tissue of guinea pigs administered a sublethal dose (11 µg/kg) of soman. A molecular network based on lipidomic and proteomics data was constructed to investigate the key molecules. The study demonstrates that subcutaneous exposure to low-dose soman for 14 consecutive days in guinea pigs impairs learning and memory. We further observed that soman exposure induces damage to both the hippocampal neurons and the mitochondrial ultrastructure in the brains of these animals. The study revealed that subacute soman exposure significantly altered the endocannabinoid system, characterized by disrupted biosynthesis and metabolism of 2-arachidonoylglycerol (2-AG), with a significant down-regulation of 2-AG lipid metabolism pathways, as well as a significant up-regulation of cannabinoid receptor 1 (CB1R) pathways. Notably, the disruption of 2-AG biosynthesis and metabolism is primarily attributed to the upregulation of the activities of three key enzymes, DAGLα, MAGL, and ABHD6. The activation of CB1R negatively feedback-regulate the cAMP/PKA pathway which further leads to dysregulation of mitochondrial homeostasis and reduced energy metabolism. Pharmacodynamic evaluations demonstrated that reversible MAGL inhibitor and ABHD6 inhibitor effectively elevate 2-AG levels in cerebral organoid models, subsequently restoring mitochondrial energy metabolism. This research expands the current understanding of soman’s systemic neurotoxicity, particularly its capacity to modulate endocannabinoid-mediated cognitive processes. Our results provide mechanistic insights into soman-induced cognitive deficits and associated health risks. Importantly, elevating 2-AG levels may serve as an effective strategy for preventing and treating soman-induced memory impairment.