Huang Yan, Chen Can-Can, Wang Ting-Ting, Qiu Yi-Hua, Peng Yu-Ping
School of Biological and Basic Medical Sciences, Soochow University, Suzhou, China.
Department of Physiology, School of Medicine, and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China.
Neuro Endocrinol Lett. 2016 Dec;37(7):491-500.
We have previously reported that dopamine D2-like receptors including D2, D3 and D4 receptors are more important in mediating modulation of T cells than dopamine D1-like receptors (D1 and D5 receptors). Here we aimed to clarify the role of D2-like receptors in regulation of differentiation and function of T lymphocyte subsets, including helper T (Th)1, Th2, Th17 and regulatory T (Treg) cells.
Lymphocytes, separated from the mesenteric lymph nodes of mice, were stimulated with concanavalin A (Con A) and treated with the D2-like receptor agonist quinpirole or the antagonist haloperidol. Expression of lymphocyte cytokines and transcription factors and dopamine D2, D3 and D4 receptors were measured by real-time quantitative polymerase chain reaction and Western blot assay. Meanwhile, cAMP and phosphorylated cAMP-response element-binding (CREB) levels in the lymphocytes were examined by enzyme-linked immunosorbent assay and Western blot assay, respectively.
Activation of D2-like receptors with the agonist quinpirole upregulated the expression of Th2- and Treg-specific transcription factors and cytokines in Con A-activated lymphocytes, but downregulated the expression of Th1- and Th17-specific transcription factors and cytokines. Simultaneously, quinpirole increased dopamine D3 and D4 receptor expression, but did not alter D2 receptor expression. However, quinpirole reduced both cAMP and phosphorylated CREB levels in Con A-activated lymphocytes. All these quinpirole effects were blocked by haloperidol, an antagonist of D2-like receptors.
D2-like receptors, principally dopamine D3 and D4 receptors, promote differentiation and function of T lymphocytes towards anti-inflammatory T cell subsets by a negative link to cAMP-CREB pathway.
我们之前报道过，包括D2、D3和D4受体在内的多巴胺D2样受体在介导T细胞调节方面比多巴胺D1样受体（D1和D5受体）更为重要。在此，我们旨在阐明D2样受体在调节T淋巴细胞亚群（包括辅助性T细胞（Th）1、Th2、Th17和调节性T细胞（Treg））的分化和功能中的作用。
从小鼠肠系膜淋巴结分离出淋巴细胞，用伴刀豆球蛋白A（Con A）刺激并用D2样受体激动剂喹吡罗或拮抗剂氟哌啶醇处理。通过实时定量聚合酶链反应和蛋白质印迹分析测量淋巴细胞细胞因子、转录因子以及多巴胺D2、D3和D4受体的表达。同时，分别通过酶联免疫吸附测定和蛋白质印迹分析检测淋巴细胞中cAMP和磷酸化环磷酸腺苷反应元件结合蛋白（CREB）的水平。
用激动剂喹吡罗激活D2样受体可上调Con A激活的淋巴细胞中Th2和Treg特异性转录因子及细胞因子的表达，但下调Th1和Th17特异性转录因子及细胞因子的表达。同时，喹吡罗增加了多巴胺D3和D4受体的表达，但未改变D2受体的表达。然而，喹吡罗降低了Con A激活的淋巴细胞中cAMP和磷酸化CREB的水平。D2样受体拮抗剂氟哌啶醇阻断了喹吡罗的所有这些作用。
D2样受体，主要是多巴胺D3和D4受体，通过与cAMP-CREB途径的负向联系促进T淋巴细胞向抗炎性T细胞亚群的分化和功能。
