Börner Christine, Bedini Andrea, Höllt Volker, Kraus Jürgen
Department of Pharmacology and Toxicology, Magdeburg University, 44 Leipzigerstrasse, 39120 Magdeburg, Germany.
Mol Pharmacol. 2008 Mar;73(3):1013-9. doi: 10.1124/mol.107.042945. Epub 2007 Dec 21.
The majority of effects of cannabinoids are mediated by the two receptors CB1 and CB2. In addition to neuronal cells, CB1 receptors are expressed in T lymphocytes, in which they are involved in cannabinoid-induced T helper cell biasing. Although basally expressed only weakly in T cells, CB1 receptors are up-regulated in these cells by stimuli such as cannabinoids themselves. This effect is mediated by interleukin-4. In this study, we investigated basal and interleukin-4-inducible expression of the CB1 gene in T lymphocytes. In a promoter analysis, two regions [nucleotides (nts) -3086 to -2490 and nts -1950 to -1653] were identified, which suppress basal transcription of the gene in Jurkat T cells, whereas the region between nts -648 and -559 enhanced basal CB1 transcription. Interleukin-4 markedly induced transcription of CB1 in Jurkat cells and primary human T cells. Experiments using transcription factor decoy oligonucleotides demonstrated that STAT6 mediates regulation of the gene by interleukin-4. Using reporter gene assays and the transcription factor decoy oligonucleotide approach, a binding site for STAT6 was identified at nt -2769 on the human CB1 gene promoter. Interleukin-4 also caused up-regulation of functional CB1 receptor proteins. In interleukin-4 pretreated, but not in naive Jurkat cells, the CB1 agonist R(+)-methanandamide caused a significant inhibition of forskolin-induced cAMP formation. This effect was blocked by the CB1-selective antagonists N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251) and 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-4-mo rpholinyl-1H-pyrazole-3-carboxamide (AM281). Taken together, these data show that CB1 receptors are expressed and up-regulated by interleukin-4 in T lymphocytes, which enables CB1-mediated communication to cells of other systems, such as neuronal cells.
大麻素的大多数作用是由两种受体CB1和CB2介导的。除神经元细胞外，CB1受体在T淋巴细胞中表达，它们参与大麻素诱导的辅助性T细胞偏向。虽然CB1受体在T细胞中基础表达较弱，但在这些细胞中会被大麻素自身等刺激上调。这种作用是由白细胞介素-4介导的。在本研究中，我们研究了T淋巴细胞中CB1基因的基础表达和白细胞介素-4诱导的表达。在启动子分析中，鉴定出两个区域[核苷酸（nts）-3086至-2490和nts -1950至-1653]，它们抑制Jurkat T细胞中该基因的基础转录，而nts -648和-559之间的区域增强CB1基础转录。白细胞介素-4显著诱导Jurkat细胞和原代人T细胞中CB1的转录。使用转录因子诱饵寡核苷酸的实验表明，STAT6介导白细胞介素-4对该基因的调控。使用报告基因测定和转录因子诱饵寡核苷酸方法，在人CB1基因启动子的nt -2769处鉴定出STAT6的结合位点。白细胞介素-4还导致功能性CB1受体蛋白上调。在白细胞介素-4预处理的Jurkat细胞中，但在未处理的细胞中没有，CB1激动剂R(+)-甲硫安非他明导致福斯可林诱导的cAMP形成显著抑制。这种作用被CB1选择性拮抗剂N-(哌啶-1-基)-5-(4-碘苯基)-1-(2,4-二氯苯基)-4-甲基-1H-吡唑-3-甲酰胺（AM251）和1-(2,4-二氯苯基)-5-(4-碘苯基)-4-甲基-N-4-吗啉基-1H-吡唑-3-甲酰胺（AM281）阻断。综上所述，这些数据表明CB1受体在T淋巴细胞中由白细胞介素-4表达并上调，这使得CB1介导的与其他系统细胞（如神经元细胞）的通讯成为可能。
