Herring A C, Faubert Kaplan B L, Kaminski N E
Department of Pharmacology and Toxicology and National Food Safety and Toxicology Center, 315 Food Safety and Toxicology Building, Michigan State University, 48824, East Lansing, MI, USA.
Cell Signal. 2001 Apr;13(4):241-50. doi: 10.1016/s0898-6568(01)00145-0.
Cannabinoid compounds inhibit the cAMP signalling cascade in leukocytes. One of these compounds, cannabinol (CBN) has been shown to inhibit interleukin-2 (IL-2) expression and the activation of cAMP response element binding protein (CREB) and nuclear factor for immunoglobulin kappa chain in B cells (NF-kappaB) following phorbol-12-myristate-13 acetate (PMA) plus ionomycin (Io) treatment of thymocytes. Therefore, the objective of the present studies was to determine the role of cAMP and protein kinase A (PKA) in the CBN-mediated inhibition of IL-2, CREB, and NF-kappaB in PMA/Io-activated thymocytes. The inhibition of CREB/ATF-1 phosphorylation, or cAMP response element (CRE) or kappaB DNA binding activity produced by CBN in PMA/Io-activated thymocytes, could not be reversed by DBcAMP costimulation. Furthermore, DBcAMP failed to reverse the concentration-dependent inhibition of IL-2 protein secretion by CBN. Pretreatment of thymocytes with H89 produced a modest inhibition of PMA/Io-induced CREB/ATF-1 phosphorylation and CRE DNA binding activity but H89 had no effect on protein binding to a kappaB motif. Additionally, H89 modestly inhibited PMA/Io-induced IL-2 secretion. In light of the modest involvement of the cAMP pathway in CBN-mediated inhibition of CREB and IL-2 in PMA/Io-activated thymocytes, PD098059 (PD), the MEK inhibitor, was utilized to determine the role of ERK MAP kinases in thymocytes. ERKs play a critical role in IL-2 production but not for CREB phsophorylation. Collectively, these findings suggest that CBN may modulate several signalling pathways in activated T cells.
大麻素化合物可抑制白细胞中的环磷酸腺苷（cAMP）信号级联反应。其中一种化合物，大麻酚（CBN）已被证明在佛波醇-12-肉豆蔻酸酯-13-乙酸酯（PMA）加离子霉素（Io）处理胸腺细胞后，能抑制白细胞介素-2（IL-2）的表达以及B细胞中环磷酸腺苷反应元件结合蛋白（CREB）和免疫球蛋白κ链核因子（NF-κB）的激活。因此，本研究的目的是确定cAMP和蛋白激酶A（PKA）在CBN介导的对PMA/Io激活的胸腺细胞中IL-2、CREB和NF-κB的抑制作用中的作用。CBN在PMA/Io激活的胸腺细胞中对CREB/ATF-1磷酸化、环磷酸腺苷反应元件（CRE）或κB DNA结合活性的抑制作用，不能被二丁酰环磷腺苷（DBcAMP）共刺激所逆转。此外，DBcAMP未能逆转CBN对IL-2蛋白分泌的浓度依赖性抑制作用。用H89预处理胸腺细胞可适度抑制PMA/Io诱导的CREB/ATF-1磷酸化和CRE DNA结合活性，但H89对与κB基序的蛋白结合没有影响。此外，H89适度抑制PMA/Io诱导的IL-2分泌。鉴于cAMP途径在CBN介导的对PMA/Io激活的胸腺细胞中CREB和IL-2的抑制作用中参与程度有限，使用MEK抑制剂PD098059（PD）来确定细胞外信号调节激酶（ERK）丝裂原活化蛋白激酶在胸腺细胞中的作用。ERK在IL-2产生中起关键作用，但对CREB磷酸化不起作用。总体而言，这些发现表明CBN可能调节活化T细胞中的多种信号通路。
