Ito Shiori, Iwaki Soichiro, Kondo Rie, Satoh Masashi, Iwabuchi Kazuya, Ohkawa Ryunosuke, Mishima Yuko, Yatomi Yutaka, Furumoto Tomoo, Tsutsui Hiroyuki, Fujii Satoshi
aDepartment of Molecular and Cellular Pathobiology and Therapeutics, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya bDivision of Immunology, Kitasato University School of Medicine, Sagamihara cDepartment of Clinical Laboratory, University of Tokyo Hospital, Tokyo dDepartment of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Coron Artery Dis. 2014 Jun;25(4):311-20. doi: 10.1097/MCA.0000000000000082.
Natural killer T (NKT) cells are unique T lymphocytes that recognize glycolipid antigen and produce various cytokines. NKT cells accelerate atherosclerosis in mice. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid and regulates T-lymphocyte trafficking. We aimed to determine the effects of S1P on the production of proinflammatory cytokine, tumor necrosis factor (TNF)-α, in NKT cell hybridomas and mouse NKT cells.
NKT cell hybridomas and sorted mouse NKT cells were stimulated with S1P and α-galactosylceramide (α-GalCer), the major ligand to produce cytokines in NKT cells. TNF-α mRNA expression and protein production were determined by real-time PCR and ELISA, respectively. Cell migration was assayed using chemotaxicell. Plasma S1P was measured using HPLC.
Hybridomas expressed S1P receptors, S1P1, S1P2, and S1P4. S1P and α-GalCer increased TNF-α mRNA expression and protein production. S1P enhanced TNF-α induction by α-GalCer. S1P receptor antagonists decreased the TNF-α mRNA expression induced by S1P. FTY720, an immunosuppressive S1P receptor modulator, also decreased the TNF-α mRNA expression. The migration of NKT cell hybridomas was increased by S1P. FTY720 reduced the migration induced by S1P. S1P also increased the TNF-α mRNA expression in mouse NKT cells. Plasma TNF-α levels in patients with high plasma S1P (≥500 nmol/l) were higher than those in patients with low S1P (<500 nmol/l).
S1P binds to S1P receptors in NKT cells and enhances TNF-α production. TNF-α overproduction may induce atherogenic inflammatory responses. S1P may serve as a novel therapeutic target for amelioration of vascular inflammatory diseases.
自然杀伤T（NKT）细胞是一类独特的T淋巴细胞，可识别糖脂抗原并产生多种细胞因子。NKT细胞可加速小鼠动脉粥样硬化的发展。1-磷酸鞘氨醇（S1P）是一种生物活性鞘脂，可调节T淋巴细胞的迁移。我们旨在确定S1P对NKT细胞杂交瘤和小鼠NKT细胞中促炎细胞因子肿瘤坏死因子（TNF）-α产生的影响。
用S1P和α-半乳糖神经酰胺（α-GalCer）刺激NKT细胞杂交瘤和分选的小鼠NKT细胞，α-GalCer是NKT细胞中产生细胞因子的主要配体。分别通过实时PCR和ELISA测定TNF-α mRNA表达和蛋白产生情况。使用趋化细胞检测细胞迁移。用高效液相色谱法测定血浆S1P。
杂交瘤表达S1P受体S1P1、S1P2和S1P4。S1P和α-GalCer可增加TNF-α mRNA表达和蛋白产生。S1P增强了α-GalCer对TNF-α的诱导作用。S1P受体拮抗剂可降低S1P诱导的TNF-α mRNA表达。免疫抑制性S1P受体调节剂FTY720也可降低TNF-α mRNA表达。S1P可增加NKT细胞杂交瘤的迁移。FTY720可减少S1P诱导的迁移。S1P还可增加小鼠NKT细胞中TNF-α mRNA表达。血浆S1P水平高（≥500 nmol/l）的患者血浆TNF-α水平高于血浆S1P水平低（<500 nmol/l）的患者。
S1P与NKT细胞中的S1P受体结合并增强TNF-α的产生。TNF-α的过度产生可能诱导致动脉粥样硬化的炎症反应。S1P可能成为改善血管炎性疾病的新型治疗靶点。
