Glycosylated <i>N</i>-Acyl Phosphoethanolamines as Bacterial Food-Dependent Signaling Molecules in <i>Caenorhabditis</i> Nematodes

<i>N</i>-acyl ethanolamines represent conserved lipophilic signaling molecules that function as endogenous ligands at G-protein-coupled receptors, ion channels, and nuclear receptors. Using a combination of comparative ultrahigh-performance liquid chromatography electrospray ionization high-resolution tandem mass spectrometry (UHPLC-ESI-HR-MS^E) analysis and microreactions, a diversity of glycosylated <i>N</i>-acyl phosphoethanolamines were characterized in <i>Caenorhabditis</i> nematodes. Representative examples were enriched by RP-C18 chromatography and identified by NMR spectroscopy. Comparative metabolomics and isotope incorporation experiments revealed that the biosynthesis of the homologous <i>N</i>-acyl building blocks (approximately 50 compounds) depends on the bacterial food source, chain elongation and desaturation of food-derived fatty acids, or their de novo biosynthesis by the nematode, whereas the biosynthesis of medium-chain <i>N</i>-acyl units depends on the peroxisomal β-oxidation cycle via the 3-ketoacyl-<i>S</i>-CoA thiolase <i>daf-22</i>. Glycosylation of these lipophilic <i>N</i>-acyl ethanolamines results in amphiphilic modular metabolites (approximately 100 identified compounds) that are released into the environment and exhibit potential signaling functions. Exclusively male-produced β-sophorosyl <i>N-</i>acyl-phosphoethanolamines like SNAP-13:1cyclo retain females of and , and its biosynthesis requires bacterial cyclo fatty acids 17:1cyclo and 19:1cyclo, thereby translating growth phase-dependent bacterial lipogeneses into a behavioral signal. Amphiphilic 2-(β-glucosyl)-glyceryl <i>N</i>-eicosapentaenoyl phosphoethanolamine (GGp-NAE-20:5), a dominating component of the metabolome, represents a water-soluble derivative of <i>N</i>-eicosapentaenoyl ethanolamine (NAE 20:5), potentially enabling intra- and interspecies endocannabinoid signaling.