title: Differential modulation by delta9-tetrahydrocannabinol (∆9)-THC) of CD40 ligand (CD40L) expression in activated mouse splenic CD4+ T cells.
abstract: The anti-inflammatory activity of cannabinoids has been widely demonstrated in experimental animal models and in humans. CD40-CD40-ligand (L) interactions are among the most crucial initiators of inflammation. This study investigated the effects of ∆(9)-THC on CD40L expression in mouse splenic T cells after activation with various stimuli. Time course studies demonstrated that peak surface expression of CD40L by CD4(+) T cells after anti-CD3/CD28 or phorbol ester plus calcium ionophore (PMA/Io) occurred 8 h post activation. Peak CD40L mRNA levels were observed at 2 h post PMA/Io treatment and at 4 h post anti-CD3/CD28 treatment. Pretreatment with ∆(9)-THC significantly impaired the upregulation of CD40L induced by anti-CD3/CD28 at both the protein and mRNA level. By contrast, ∆(9)-THC did not affect PMA/Io-induced surface CD40L expression on CD4(+) T cells. Additionally, ∆(9)-THC also attenuated anti-CD3/CD28-induced CD40L expression on CD4(+) T cells derived from CB1(-/-)/CB2(-/-) mice. We investigated whether the mechanism by which ∆(9)-THC suppressed CD40L expression involved putative cannabinoid activation of the glucocorticoid receptor (GR). Although activation of GR resulted in suppression of CD40L induction by anti-CD3/CD28, no interaction between ∆(9)-THC and GR was observed by a glucocorticoid response element (GRE) luciferase reporter assay in HEK293T cells. Collectively, these results suggest that ∆(9)-THC targets proximal T cell receptor-associated signaling in a cannabinoid receptor- and glucocorticoid receptor-independent manner. These findings identify suppression of CD40L expression as a novel part of the mechanism by which ∆(9)-THC exerts anti-inflammatory activity.
authors.affiliation: Department of Pharmacology & Toxicology and Center of Integrative Toxicology, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Thitirat
authors.initials: T
authors.lastname: Ngaotepprutaram
authors.forename: Barbara L F
authors.initials: BL
authors.lastname: Kaplan
authors.forename: Robert B
authors.initials: RB
authors.lastname: Crawford
authors.forename: Norbert E
authors.initials: NE
authors.lastname: Kaminski
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D019013:CD40 Antigens / Q000096:biosynthesis*; D013759:Dronabinol / Q000494:pharmacology*; D005260:Female; D005434:Flow Cytometry; D057809:HEK293 Cells; D006213:Hallucinogens / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D010957:Plasmids / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D011965:Receptors, Glucocorticoid / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000378:metabolism; D014162:Transfection
chemical_list: D019013:CD40 Antigens; D006213:Hallucinogens; D012333:RNA, Messenger; D011965:Receptors, Glucocorticoid; D013759:Dronabinol