Mohagheghpour N, Abel K, La Paglia N, Emanuele N V, Azad N
Kuzell Institute for Arthritis and Infectious Diseases, California Pacific Medical Center Research Institute, San Francisco 94115, USA.
Cell Immunol. 1995 Jul;163(2):280-8. doi: 10.1006/cimm.1995.1127.
We have previously demonstrated that both human CD4+ and CD8+ T lymphocytes produce enhanced levels of luteinizing hormone-releasing hormone (LHRH) mRNA and peptide upon stimulation with monoclonal antibody directed at the CD3 component of the T cell receptor for antigen (TCR) or mitogenic lectin. In the current study, we define the signaling pathways that control TCR-mediated LHRH production by using agents known to affect distinct signals, and compare the messenger systems required for LHRH response to other T-cell-associated activation responses, such as expression of CD69 and interleukin-2 receptor (IL-2R) molecules and production of interleukin-2 (IL-2). Results indicate that the activation of protein kinase C (PKC) is essential for LHRH production by previously nonstimulated T cells, not increased concentration of cytosolic-free calcium ([Ca2+]i). Phorbol ester (PMA), a direct activator of PKC, provoked LHRH production and cell surface expression of CD69 and IL-2R molecules by T cells, but not IL-2 synthesis. The synthesis of IL-2 by T cells required costimulation with PMA and ionomycin, a Ca2+ ionophore. Consistent with these observations, H7, an inhibitor of PKC, prevented T cells from producing LHRH upon activation with mitogen. However, LHRH production was not suppressed by HA1004, which inhibits all cyclic nucleotide-dependent protein kinases except for PKC. Genistein, a selective inhibitor of protein tyrosine kinase, blocked PMA-induced increase in LHRH production, but not CD69 and IL-2R expression, suggesting that protein tyrosine phosphorylation events distal from PKC activation may play a role in regulating LHRH response.
我们之前已经证明，用针对抗原的T细胞受体（TCR）的CD3成分的单克隆抗体或促有丝分裂凝集素刺激后，人类CD4⁺和CD8⁺ T淋巴细胞会产生更高水平的促黄体生成激素释放激素（LHRH）mRNA和肽。在当前的研究中，我们使用已知影响不同信号的试剂来确定控制TCR介导的LHRH产生的信号通路，并比较LHRH反应所需的信使系统与其他T细胞相关激活反应所需的信使系统，如CD69和白细胞介素-2受体（IL-2R）分子的表达以及白细胞介素-2（IL-2）的产生。结果表明，蛋白激酶C（PKC）的激活对于先前未受刺激的T细胞产生LHRH至关重要，而非细胞内游离钙（[Ca²⁺]i）浓度的增加。佛波酯（PMA）是PKC的直接激活剂，可引发T细胞产生LHRH以及CD69和IL-2R分子的细胞表面表达，但不会引发IL-2的合成。T细胞合成IL-2需要PMA和离子霉素（一种Ca²⁺离子载体）共同刺激。与这些观察结果一致，PKC抑制剂H7可阻止T细胞在用有丝分裂原激活后产生LHRH。然而，HA1004不会抑制LHRH的产生，HA1004可抑制除PKC外的所有环核苷酸依赖性蛋白激酶。染料木黄酮是一种蛋白酪氨酸激酶的选择性抑制剂，可阻断PMA诱导的LHRH产生增加，但不会阻断CD69和IL-2R的表达，这表明PKC激活远端的蛋白酪氨酸磷酸化事件可能在调节LHRH反应中起作用。
