Cannabinol enhancement of interleukin-2 (IL-2) expression by T cells is associated with an increase in IL-2 distal nuclear factor of activated T cell activity.
It has been demonstrated previously that cannabinol (CBN) differentially modulates interleukin-2 (IL-2) protein secretion by T cells with a corresponding change in extracellular signal-regulated kinase activity. The objective of the present studies was to further investigate the molecular mechanism by which CBN enhances IL-2 gene expression using the EL4 T cell line. We demonstrate here that steady-state IL-2 mRNA expression was significantly enhanced by CBN in a concentration-dependent manner in EL4 cells activated with suboptimal concentrations of phorbol-12-myristate-13-acetate (2-10 nM). Concordantly, a marked increase was observed in nuclear factor of activated T cells (NF-AT) DNA binding activity to the IL-2 distal NF-AT site, but not to nuclear factor for immunoglobulin kappa chain in B cells or activator protein 1 motifs. Transient transfection of EL4 cells with a reporter gene under the control of multiple IL-2 distal NF-AT motifs exhibited increased transcriptional activity by CBN in suboptimally activated cells. In addition, the CBN-mediated enhancement of IL-2 protein secretion and the transcriptional activity of the IL-2 distal NF-AT reporter gene was abrogated by the calcium/calmodulin-dependent protein kinase inhibitor KN93, but not by the CB2 receptor antagonist SR144528. Enhancement of IL-2 was also demonstrated with CP55940, Delta(9)-tetrahydrocannabinol, and cannabidiol, thus suggesting that the phenomenon is not unique to CBN. Collectively, these results suggest that increased IL-2 secretion by CBN is mediated through the enhancement of IL-2 gene transcription by activation of NF-AT in a CB1/CB2-independent manner.
Jan
Tong-Rong
TR
Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan 48824, USA.
Rao
Gautham K
GK
Kaminski
Norbert E
NE
D020816:Amino Acid Motifs; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000502:physiology; D001892:Camphanes / Q000494:pharmacology; D002187:Cannabinol / Q000494:pharmacology*; D003511:Cyclohexanols / Q000494:pharmacology; D004247:DNA / Q000187:drug effects / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D013759:Dronabinol / Q000494:pharmacology; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000378:metabolism; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D011720:Pyrazoles / Q000494:pharmacology; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug / Q000037:antagonists & inhibitors; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection
D001892:Camphanes; D003511:Cyclohexanols; D004268:DNA-Binding Proteins; D007376:Interleukin-2; D016328:NF-kappa B; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D011720:Pyrazoles; D012333:RNA, Messenger; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug; C110630:SR 144528; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D013759:Dronabinol; D002187:Cannabinol; C054649:3-(2-hydroxy-4-(1,1-dimethylheptyl)phenyl)-4-(3-hydroxypropyl)cyclohexanol; D004247:DNA; D017871:Calcium-Calmodulin-Dependent Protein Kinases