Presence and regulation of the endocannabinoid system in human dendritic cells.
Cannabinoid receptors and their endogenous ligands, the endocannabinoids, have been detected in several blood immune cells, including monocytes/macrophages, basophils and lymphocytes. However, their presence in dendritic cells, which play a key role in the initiation and development of the immune response, has never been investigated. Here we have analyzed human dendritic cells for the presence of the endocannabinoids, anandamide and 2-arachidonoylglycerol (2-AG), the cannabinoid CB1 and CB2 receptors, and one of the enzymes mostly responsible for endocannabinoid hydrolysis, the fatty acid amide hydrolase (FAAH). By using a very sensitive liquid chromatography-atmospheric pressure chemical ionization-mass spectrometric (LC-APCI-MS) method, lipids extracted from immature dendritic cells were shown to contain 2-AG, anandamide and the anti-inflammatory anandamide congener, N-palmitoylethanolamine (PalEtn) (2.1 +/- 1.0, 0.14 +/- 0.02 and 8.2 +/- 3.9 pmol x 10(-7) cells, respectively). The amounts of 2-AG, but not anandamide or PalEtn, were significantly increased following cell maturation induced by bacterial lipopolysaccharide (LPS) or the allergen Der p 1 (2.8- and 1.9-fold, respectively). By using both RT-PCR and Western immunoblotting, dendritic cells were also found to express measurable amounts of CB1 and CB2 receptors and of FAAH. Cell maturation did not consistently modify the expression of these proteins, although in some cell preparations a decrease of the levels of both CB1 and CB2 mRNA transcripts was observed after LPS stimulation. These findings demonstrate for the first time that the endogenous cannabinoid system is present in human dendritic cells and can be regulated by cell activation.
Matias
Isabel
I
Endocannabinoid Research Group, Istituto di Chimica Biomolecolare, Consiglio Nazionale delle Ricerche, Comprensorio Olivetti, Pozzuoli (Napoli), Italy.
Pochard
Pierre
P
Orlando
Pierangelo
P
Salzet
Michel
M
Pestel
Joel
J
Di Marzo
Vincenzo
V
D000581:Amidohydrolases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D039741:Antigens, Dermatophagoides; D001095:Arachidonic Acids / Q000032:analysis / Q000378:metabolism; D063385:Cannabinoid Receptor Modulators; D002186:Cannabinoids / Q000378:metabolism*; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D063388:Endocannabinoids; D005989:Glycerides / Q000032:analysis / Q000378:metabolism; D006023:Glycoproteins / Q000494:pharmacology; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D008969:Molecular Sequence Data; D053284:Polyunsaturated Alkamides; D051381:Rats; D011919:Rats, Inbred Strains; D043885:Receptor, Cannabinoid, CB2; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D000099252:Fatty Acid Amide Hydrolases
D000581:Amidohydrolases; D039741:Antigens, Dermatophagoides; D001095:Arachidonic Acids; D063385:Cannabinoid Receptor Modulators; D002186:Cannabinoids; D063388:Endocannabinoids; D005989:Glycerides; D006023:Glycoproteins; D008070:Lipopolysaccharides; D053284:Polyunsaturated Alkamides; D043885:Receptor, Cannabinoid, CB2; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug; D000099252:Fatty Acid Amide Hydrolases; C469526:Cnr2 protein, rat; C094503:glyceryl 2-arachidonate; C078814:anandamide