Monoacylglycerols activate TRPV1--a link between phospholipase C and TRPV1

• Published in: PloS one 2013-12, Vol.8 (12), p.e81618-e81618
• Main Authors: Zygmunt, Peter M, Ermund, Anna, Movahed, Pouya, Andersson, David A, Simonsen, Charlotte, Jönsson, Bo A G, Blomgren, Anders, Birnir, Bryndis, Bevan, Stuart, Eschalier, Alain, Mallet, Christophe, Gomis, Ana, Högestätt, Edward D
• Format: Article
• Language: English
• Subjects: 2-Arachidonoylglycerol; Activation; Adenosine triphosphate; Animals; Arachidonic Acids - biosynthesis; Arteries; ATP; Basic Medicine; Benzodioxoles - pharmacology; Bioassays; Bradykinin; Brain; Brain research; Calcineurin; Capsaicin receptors; Capsazepine; Deuterium; Diglycerides; Dorsal root ganglia; Drosophila; Endocannabinoids - biosynthesis; Farmakologi och toxikologi; Fatty acids; Female; Fibers; Ganglia; Ganglia, Spinal - cytology; Ganglia, Spinal - drug effects; Ganglia, Spinal - metabolism; Glycerides - biosynthesis; HEK293 Cells; Histamine; Humans; Inhibitors; Inositol 1,4,5-trisphosphate receptors; Insects; Ion channels; Kinases; Laboratories; Life Sciences; Ligands; Lipase; Lipoprotein lipase; Läkemedelskemi; Male; Medical and Health Sciences; Medicin och hälsovetenskap; Medicinal Chemistry; Medicine; Medicinska och farmaceutiska grundvetenskaper; Metabolism; Metabolites; Mice; Monoglycerides; Monoglycerides - biosynthesis; Monoglycerides - metabolism; Neurosciences; Nociception - drug effects; Pain; Pain perception; Palmitoylethanolamide; Pharmacology and Toxicology; Phosphatidylinositol 4,5-diphosphate; Phospholipase; Phospholipase C; Phospholipases; Physiological aspects; Physiology; Piperidines - pharmacology; Protons; Rats; Receptors; Rodents; Sensory neurons; Sensory Receptor Cells - cytology; Sensory Receptor Cells - drug effects; Sensory Receptor Cells - metabolism; Signaling; TRPV Cation Channels - metabolism; Type C Phospholipases - metabolism; Veins & arteries
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0081618

Phospholipase C-mediated hydrolysis of phosphatidylinositol 4,5-bisphosphate generates diacylglycerol, inositol 1,4,5-trisphosphate and protons, all of which can regulate TRPV1 activity via different mechanisms. Here we explored the possibility that the diacylglycerol metabolites 2-arachidonoylglycerol and 1-arachidonoylglycerol, and not metabolites of these monoacylglycerols, activate TRPV1 and contribute to this signaling cascade. 2-Arachidonoylglycerol and 1-arachidonoylglycerol activated native TRPV1 on vascular sensory nerve fibers and heterologously expressed TRPV1 in whole cells and inside-out membrane patches. The monoacylglycerol lipase inhibitors methylarachidonoyl-fluorophosphonate and JZL184 prevented the metabolism of deuterium-labeled 2-arachidonoylglycerol and deuterium-labeled 1-arachidonoylglycerol in arterial homogenates, and enhanced TRPV1-mediated vasodilator responses to both monoacylglycerols. In mesenteric arteries from TRPV1 knock-out mice, vasodilator responses to 2-arachidonoylglycerol were minor. Bradykinin and adenosine triphosphate, ligands of phospholipase C-coupled membrane receptors, increased the content of 2-arachidonoylglycerol in dorsal root ganglia. In HEK293 cells expressing the phospholipase C-coupled histamine H1 receptor, exposure to histamine stimulated the formation of 2-AG, and this effect was augmented in the presence of JZL184. These effects were prevented by the diacylglycerol lipase inhibitor tetrahydrolipstatin. Histamine induced large whole cell currents in HEK293 cells co-expressing TRPV1 and the histamine H1 receptor, and the TRPV1 antagonist capsazepine abolished these currents. JZL184 increased the histamine-induced currents and tetrahydrolipstatin prevented this effect. The calcineurin inhibitor ciclosporin and the endogenous "entourage" compound palmitoylethanolamide potentiated the vasodilator response to 2-arachidonoylglycerol, disclosing TRPV1 activation of this monoacylglycerol at nanomolar concentrations. Furthermore, intracerebroventricular injection of JZL184 produced TRPV1-dependent antinociception in the mouse formalin test. Our results show that intact 2-arachidonoylglycerol and 1-arachidonoylglycerol are endogenous TRPV1 activators, contributing to phospholipase C-dependent TRPV1 channel activation and TRPV1-mediated antinociceptive signaling in the brain.