Roles of muscarinic receptors m1 and m2 on interleukin 2 production in human peripheral blood lymphocytes and human leukemic T cell line Jurkat cells ヒト末梢血リンパ球およびヒト株化T細胞Jurkatのインターロイキン2産生におけるm1、m2ムスカリン性受容体の役割

博士論文

In this study, I found the existence of muscarinic acetylcholine (mACh) receptors in human peripheral blood lymphocyte (hPBL) as well as in human leukemic T cell line Jurkat cells, and examined the roles of the mACh receptors in interleukin-2 (IL-2) production in the cells. In the first section, I examined the effects of a nonselective muscarinic receptor agonist, oxtremorine-M (Oxo-M), on IL-2 production in hPBL. The mACh receptor subtype genes have been characterized as m1 to m5 (1). I found that m1 and m2 subtype receptor mRNAs are expressed in hPBL and the pretreatment of the receptors with Oxo-M enhanced IL-2 production(2). I demonstrated that Jurkat cells also expressed m1 and m2 receptor mRNAs. In the second section, I examined the physiological roles of the m1 and m2 receptors in Jurkat cells. The results showed that the m1 subtype stimulation enhanced IL-2 production, while the m2 subtype stimulation decreased it through the regulation of mitogen-activated protein kinase (MAPK)- and c-Jun N-terminal kinase (JNK)-medjated pathways. In the third section, I examined the effects of cyclic AMP (cAMP) on IL-2 production. Pretreatment with dibutyryl cAMP (DBcAMP) for 24 hr enhanced IL-2 production in Jurkat cells. Fluorescence-activated cell sorter (FACS) analysis demonstrated that Jurkat cells were arrested in G1 phase by DBcAMP treatment. The enhancement of IL-2 production seemed to be correlated to the cell cycle progression. Although the m2 receptors are known to couple with Gi protein which inhibits cAMP accumulation. There were no effects of the m2 receptor stimulation on the cell cycle in Jurkat cells. In the sections 2 and 3, stimulation of m2 receptors for 18 hr did not affect the amount of cAMP, after PMA/A23187 stimulation for 30 min caused decreases of AP-1. Concomitant stimulation with m2 receptors and PMA/A23187 for 30 min decreased the amount of cAMP and caused decreases of AP-1 and NF-kB. The relationships of these events must be clarified in the future. These findings may be important steps to further clarify the functional roles and the intracellular mechanism of the neuro-immune interaction.