Genetic Manipulation of sn-1-Diacylglycerol Lipase and CB Cannabinoid Receptor Gain-of-Function Uncover Neuronal 2-Linoleoyl Glycerol Signaling in .

In mammals, sn-1-diacylglycerol lipases (DAGL) generate 2-arachidonoylglycerol (2-AG) that, as the major endocannabinoid, modulates synaptic neurotransmission by acting on CB1 cannabinoid receptors (CBR). Even though the insect genome codes for , which is a DAGL ortholog (dDAGL), its products and their functions remain unknown particularly because insects lack chordate-type cannabinoid receptors. Gain-of-function and loss-of-function genetic manipulations were carried out in , including the generation of both dDAGL-deficient and mammalian CBR-overexpressing flies. Neuroanatomy, dietary manipulations coupled with targeted mass spectrometry determination of arachidonic acid and 2-linoleoyl glycerol (2-LG) production, behavioral assays, and signal transduction profiling for Akt and Erk kinases were employed. Findings from were validated by a CBR-binding assay for 2-LG in mammalian cortical homogenates with functionality confirmed in neurons using high-throughput real-time imaging . In this study, we show that dDAGL is primarily expressed in the brain and nerve cord of during larval development and in adult with 2-LG being its chief product as defined by dietary precursor availability. Overexpression of the human CBR in the ventral nerve cord compromised the mobility of adult . The causality of 2-LG signaling to CBR-induced behavioral impairments was shown by inactivation normalizing defunct motor coordination. The 2-LG-induced activation of transgenic CBRs affected both Akt and Erk kinase cascades by paradoxical signaling. Data from models were substantiated by showing 2-LG-mediated displacement of [H]CP 55,940 in mouse cortical homogenates and reduced neurite extension and growth cone collapsing responses in cultured mouse neurons. Overall, these results suggest that 2-LG is an endocannabinoid-like signal lipid produced by dDAGL in .