Cannabinoid inhibition of adenylate cyclase-mediated signal transduction and interleukin 2 (IL-2) expression in the murine T-cell line, EL4.IL-2.
Cannabinoid receptors negatively regulate adenylate cyclase through a pertussis toxin-sensitive GTP-binding protein. In the present studies, signaling via the adenylate cyclase/cAMP pathway was investigated in the murine thymoma-derived T-cell line, EL4.IL-2. Northern analysis of EL4.IL-2 cells identified the presence of 4-kilobase CB2 but not CB1 receptor-subtype mRNA transcripts. Southern analysis of genomic DNA digests for the CB2 receptor demonstrated identical banding patterns for EL4.IL-2 cells and mouse-derived DNA, both of which were dissimilar to DNA isolated from rat. Treatment of EL4.IL-2 cells with either cannabinol or Delta9-THC disrupted the adenylate cyclase signaling cascade by inhibiting forskolin-stimulated cAMP accumulation which consequently led to a decrease in protein kinase A activity and the binding of transcription factors to a CRE consensus sequence. Likewise, an inhibition of phorbol 12-myristate 13-acetate (PMA)/ionomycin-induced interleukin 2 (IL-2) protein secretion, which correlated to decreased IL-2 gene transcription, was induced by both cannabinol and Delta9-THC. Further, cannabinoid treatment also decreased PMA/ionomycin-induced nuclear factor binding to the AP-1 proximal site of the IL-2 promoter. Conversely, forskolin enhanced PMA/ionomycin-induced AP-1 binding. These findings suggest that inhibition of signal transduction via the adenylate cyclase/cAMP pathway induces T-cell dysfunction which leads to a diminution in IL-2 gene transcription.
Condie
R
R
Department of Pharmacology & Toxicology, Michigan State University, East Lansing, Michigan 48824-1317, USA.
Herring
A
A
Koh
W S
WS
Lee
M
M
Kaminski
N E
NE
D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002187:Cannabinol / Q000494:pharmacology*; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D017931:DNA Primers; D013759:Dronabinol / Q000494:pharmacology*; D005260:Female; D007376:Interleukin-2 / Q000235:genetics*; D015759:Ionomycin / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D015534:Trans-Activators / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism
D000067956:Adenylyl Cyclase Inhibitors; D017931:DNA Primers; D007376:Interleukin-2; D012333:RNA, Messenger; D015534:Trans-Activators; D018808:Transcription Factor AP-1; D015759:Ionomycin; D013759:Dronabinol; D002187:Cannabinol; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D013755:Tetradecanoylphorbol Acetate