Jeon Y J, Yang K H, Pulaski J T, Kaminski N E
Department of Pharmacology, Michigan State University, East Lansing, USA.
Mol Pharmacol. 1996 Aug;50(2):334-41.
delta 9-Tetrahydrocannabinol (delta 9-THC) a prototypic compound belonging to the family of agents known as cannabinoids, produces a wide variety of biological effects, including inhibition of immune function. The putative mechanism for cannabinoid biological action involves binding to cannabinoid receptor types 1 and 2 (CB1 and CB2) to negatively regulate adenylate cyclase and inhibit intracellular signaling via the cAMP cascade. In the current study, we show that delta 9-THC produces a marked inhibition of inducible nitric oxide synthase (iNOS) transcription and nitric oxide production by the macrophage line RAW 264.7 in response to lipopolysaccharide (LPS). Analysis of RAW 264.7 cell RNA demonstrated transcripts for CB2 but not CB1. Treatment of RAW 264.7 with delta 9-THC inhibited forskolin-stimulated cAMP production in a dose-related manner, verifying the expression of functional cannabinoid receptors by this cell line. iNOS transcription, which is regulated in part by the nuclear factor-kappa B/Rel (NF-kappa B/Rel) family of transcription factors, has been shown to be under the control of the cAMP signaling cascade. We demonstrate that delta 9-THC inhibits the activation and binding of NF-kappa B/Rel proteins to their cognate DNA site, kappa B, in response to LPS stimulation. LPS treatment of RAW 264.7 cells also induced the activation of the cAMP cascade, as indicated by an increase in binding of nuclear factors to the cAMP response element. Activation of CRE binding proteins was inhibited by delta 9-THC. Forskolin treatment of RAW 264.7 cells induced both kappa B and cAMP response element binding activity and was likewise inhibited by delta 9-THC. Collectively, this series of experiments indicates that NF-kappa B/Rel is positively regulated by the cAMP cascade to help initiate iNOS gene expression in response to LPS stimulation of macrophages. This activation of iNOS is attenuated by delta 9-THC through the inhibition of cAMP signaling.
δ9 - 四氢大麻酚（δ9 - THC）是一种属于大麻素类药物家族的原型化合物，具有多种生物学效应，包括抑制免疫功能。大麻素生物作用的推测机制涉及与1型和2型大麻素受体（CB1和CB2）结合，以负向调节腺苷酸环化酶并通过cAMP级联抑制细胞内信号传导。在本研究中，我们表明δ9 - THC对巨噬细胞系RAW 264.7响应脂多糖（LPS）诱导的一氧化氮合酶（iNOS）转录和一氧化氮产生具有显著抑制作用。对RAW 264.7细胞RNA的分析显示有CB2转录本，但没有CB1转录本。用δ9 - THC处理RAW 264.7以剂量相关方式抑制了福斯高林刺激的cAMP产生，证实了该细胞系功能性大麻素受体的表达。iNOS转录部分受核因子 - κB/Rel（NF - κB/Rel）转录因子家族调控，已证明其受cAMP信号级联控制。我们证明，δ9 - THC抑制NF - κB/Rel蛋白在LPS刺激下的激活及其与同源DNA位点κB的结合。用LPS处理RAW 264.7细胞也诱导了cAMP级联的激活，表现为核因子与cAMP反应元件结合增加。δ9 - THC抑制了CRE结合蛋白的激活。用福斯高林处理RAW 264.7细胞诱导了κB和cAMP反应元件结合活性，同样也被δ9 - THC抑制。总体而言，这一系列实验表明，NF - κB/Rel受cAMP级联正向调节，以帮助启动巨噬细胞在LPS刺激下的iNOS基因表达。iNOS的这种激活被δ9 - THC通过抑制cAMP信号传导而减弱。
