Extracellular signal regulated protein kinase and c-Jun N-terminal kinase are involved in m1 muscarinic receptor-enhanced interleukin-2 production pathway in Jurkat cells

We have previously shown that m1 and m2 muscarinic receptors were expressed on human peripheral blood lymphocytes (hPBL) and that pre-stimulation of t hese receptors enhanced phytohemagglutinin (PHA)-induced interleukin-2 (IL- 2) production, possible intracellular signal pathways of muscarinic recepto rs to regulate IL-2 production were examined in human T cell line Jurkat ce lls. Pretreatment of the cells with muscarinic receptor agonist, oxotremori ne M (Oxo-M), enhanced IL-2 production induced by phorbol 12-myristate 13-a cetate (PMA)/A23187, while Oxo-M by itself did not affect IL-2 production. The enhancement of IL-2 production by Oro-hl was inhibited by 4-diphenylace toxy-N-methylpiperidine methiodide (4-DAMP) an m1/m3 receptor antagonist. W hen the cells were pretreated with AF-DX116, an mi antagonist, the IL-2 pro duction enhanced by Oxo-M was further stimulated, Reverse transcription-pol ymerase chain reaction (RT-PCR) revealed that mi and m2 muscarinic receptor s exist on Jurkat cells, The stimulation of m1 receptors enhanced the PMA/A23187-induced binding act ivity to AP-1 consensus sequences in IL-2 promoter and production of c-Fos and c-Jun protein. The! stimulation of mi receptors did not modify the DNA binding of NF-kappa B, NF-AT or Oct-1. When mi receptors were stimulated, a ctivities of mitogen-activated protein kinase (MAPK)/extracellular signal r egulated protein kinase (ERK) and c-Jun N-terminal kinase (JNK) were increa sed, while p38 MAPK was not affected. incubation with Oxo-M induced a trans ient increase in [Ca2+](i), which was abolished by pretreatment with 4-DAMP . Treatment with cyclosporin A markedly decreased the PMA/A23187-induced IL -2 promoter activity. This treatment, however, did not affect the enhanceme nt of the promoter activity induced by mi receptor stimulation. The results suggest that transcription factor AP-1 is involved in the m1 re ceptor-mediated enhancement of IL-2 transcript in Jurkat cells, and that pa thways via MAPK/ERK and JNK, but not via p38 MAPK, are involved in the mi r eceptor-mediated enhancement of IL-2 promoter activity.