A Biosynthetic Pathway for Anandamide

• Published in: Proceedings of the National Academy of Sciences - PNAS 2006-09, Vol.103 (36), p.13345-13350
• Main Authors: Liu, Jie, Wang, Lei, Harvey-White, Judith, Osei-Hyiaman, Douglas, Razdan, Raj, Gong, Qian, Chan, Andrew C., Zhou, Zhifeng, Huang, Bill X., Kim, Hee-Yong, Kunos, George
• Format: Article
• Language: English
• Subjects: Animals; Arachidonic Acids - biosynthesis; Autoimmune diseases; Biological Sciences; Brain; Brain - metabolism; Cannabinoids - biosynthesis; Cell Line; Cell lines; Complementary DNA; DNA, Complementary; Endocannabinoids; Enzyme Inhibitors - pharmacology; Enzymes; Immunohistochemistry; In Vitro Techniques; Kinetics; Lipids; Lipopolysaccharides - pharmacology; Macrophages; Macrophages - drug effects; Macrophages - metabolism; Messenger RNA; Mice; Mice, Knockout; Neurons; Phosphatases; Phosphatidylethanolamines - metabolism; Plasmids; Polymerase chain reaction; Polyunsaturated Alkamides; Protein Tyrosine Phosphatase, Non-Receptor Type 22; Protein Tyrosine Phosphatases - genetics; Protein Tyrosine Phosphatases - metabolism; Recombinant Proteins - metabolism; RNA, Messenger - metabolism; Rodents; Small interfering RNA; Solvents; Transfection; Type C Phospholipases - metabolism
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0601832103

The endocannabinoid arachidonoyl ethanolamine (anandamide) is a lipid transmitter synthesized and released "on demand" by neurons in the brain. Anandamide is also generated by macrophages where its endotoxin (LPS)-induced synthesis has been implicated in the hypotension of septic shock and advanced liver cirrhosis. Anandamide can be generated from its membrane precursor, N-arachidonoyl phosphatidylethanolamine (NAPE) through cleavage by a phospholipase D (NAPE-PLD). Here we document a biosynthetic pathway for anandamide in mouse brain and RAW264.7 macrophages that involves the phospholipase C (PLC)-catalyzed cleavage of NAPE to generate a lipid, phosphoanandamide, which is subsequently dephosphorylated by phosphatases, including PTPN22, previously described as a protein tyrosine phosphatase. Bacterial endotoxin (LPS)-induced synthesis of anandamide in macrophages is mediated exclusively by the PLC/phosphatase pathway, which is up-regulated by LPS, whereas NAPE-PLD is down-regulated by LPS and functions as a salvage pathway of anandamide synthesis when the PLC/phosphatase pathway is compromised. Both PTPN22 and endocannabinoids have been implicated in autoimmune diseases, suggesting that the PLC/phosphatase pathway of anandamide synthesis may be a pharmacotherapeutic target.