R(+)-methanandamide induces cyclooxygenase-2 expression in human neuroglioma cells via a non-cannabinoid receptor-mediated mechanism.
Cannabinoids affect prostaglandin (PG) formation in the central nervous system through as yet unidentified mechanisms. Using H4 human neuroglioma cells, the present study investigates the effect of R(+)-methanandamide (metabolically stable analogue of the endocannabinoid anandamide) on the expression of the cyclooxygenase-2 (COX-2) enzyme. Incubation of cells with R(+)-methanandamide was accompanied by concentration-dependent increases in COX-2 mRNA, COX-2 protein, and COX-2-dependent PGE(2) synthesis. Moreover, treatment of cells with R(+)-methanandamide in the presence of interleukin-1beta led to an overadditive induction of COX-2 expression. The stimulatory effect of R(+)-methanandamide on COX-2 expression was mimicked by the structurally unrelated cannabinoid Delta(9)-tetrahydrocannabinol. Stimulation of both COX-2 mRNA expression and subsequent PGE(2) synthesis by R(+)-methanandamide was not affected by the selective CB(1) receptor antagonist AM-251 or the G(i/o) protein inactivator pertussis toxin. Enhancement of COX-2 expression by R(+)-methanandamide was paralleled by time-dependent phosphorylations of p38 mitogen-activated protein kinase (MAPK) and p42/44 MAPK. Consistent with the activation of both kinases, R(+)-methanandamide-induced COX-2 mRNA expression and PGE(2) formation were abrogated in the presence of specific inhibitors of p38 MAPK (SB203580) and p42/44 MAPK activation (PD98059). Together, our results demonstrate that R(+)-methanandamide induces COX-2 expression in human neuroglioma cells via a cannabinoid receptor-independent mechanism involving activation of the MAPK pathway. In conclusion, induction of COX-2 expression may represent a novel mechanism by which cannabinoids mediate PG-dependent effects within the central nervous system.
Ramer
R
R
Department of Experimental and Clinical Pharmacology and Toxicology, Friedrich Alexander University Erlangen-Nürnberg, Fahrstrasse 17, Erlangen, D-91054, Germany.
Brune
K
K
Pahl
A
A
Hinz
B
B
D018712:Analgesics, Non-Narcotic / Q000494:pharmacology; D001095:Arachidonic Acids / Q000494:pharmacology*; D015153:Blotting, Western; D001932:Brain Neoplasms / Q000201:enzymology*; D063385:Cannabinoid Receptor Modulators; D002460:Cell Line; D002490:Central Nervous System / Q000378:metabolism; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D013759:Dronabinol / Q000494:pharmacology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D005910:Glioma / Q000201:enzymology*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007375:Interleukin-1 / Q000378:metabolism; D007527:Isoenzymes / Q000096:biosynthesis*; D008565:Membrane Proteins; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D037342:Pertussis Toxin; D010766:Phosphorylation; D010880:Piperidines / Q000494:pharmacology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D011720:Pyrazoles / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014407:Tumor Cells, Cultured; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases
D018712:Analgesics, Non-Narcotic; D001095:Arachidonic Acids; D063385:Cannabinoid Receptor Modulators; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D007375:Interleukin-1; D007527:Isoenzymes; D008565:Membrane Proteins; D010880:Piperidines; D011720:Pyrazoles; D011725:Pyridines; D012333:RNA, Messenger; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug; D010566:Virulence Factors, Bordetella; C088155:methanandamide; C103505:AM 251; D013759:Dronabinol; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D037342:Pertussis Toxin; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D015232:Dinoprostone; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one