Patel Arti B, Theoharides Theoharis C
Molecular Immunopharmacology and Drug Discovery Laboratory, Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, Massachusetts (A.B.P. and T.C.T.); Graduate Program in Cell, Molecular and Developmental Biology, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachusetts (A.B.P.); Departments of Internal Medicine and Psychiatry, Tufts University School of Medicine and Tufts Medical Center, Boston, Massachusetts (T.C.T.).
Molecular Immunopharmacology and Drug Discovery Laboratory, Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, Massachusetts (A.B.P. and T.C.T.); Graduate Program in Cell, Molecular and Developmental Biology, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachusetts (A.B.P.); Departments of Internal Medicine and Psychiatry, Tufts University School of Medicine and Tufts Medical Center, Boston, Massachusetts (T.C.T.)
J Pharmacol Exp Ther. 2017 Jun;361(3):462-471. doi: 10.1124/jpet.117.240564. Epub 2017 Apr 12.
Mast cells (MCs) are critical for allergic reactions but are also important in inflammatory processes. Stimulation by neuropeptides, such as substance P (SP) and neurotensin (NT), leads to release of preformed molecules stored in numerous MC secretory granules and newly synthesized proinflammatory mediators, including tumor necrosis factor, C-X-C motif chemokine ligand 8, and vascular endothelial growth factor. Here, we investigate the role of mammalian target of rapamycin (mTOR) signaling in the stimulation of cultured human LAD2 MCs by NT or SP, as well as the inhibitory effect of the natural flavonoids 3',4',5,7-tetrahydroxyflavone (luteolin) and its novel structural analog 3',4',5,7-tetramethoxyflavone (methoxyluteolin). Stimulation by NT (10 M) or SP (1 M) increases ( < 0.0001) gene expression (after 6 hours) and release (after 24 hours) of tumor necrosis factor, C-X-C motif chemokine ligand 8, and vascular endothelial growth factor. This occurs via activation of both mTOR complexes, as denoted by the increased phosphorylated (p) protein levels ( < 0.0001) of the downstream mTORC1 substrate pp70S6KThr389 and mTORC2 component pmTORSer2448. Pretreatment of human MCs using the mTORC1 inhibitor rapamycin, the mTORC1/mTORC2 inhibitor Torin1, or the two flavonoids decreases both gene expression and release ( < 0.0001) of all three mediators. Methoxyluteolin is a more potent human MC inhibitor than luteolin or Torin1, implicating other MC protein targets in addition to the mTOR complex. These findings indicate that mTOR is partially involved in the neuropeptide stimulation of MCs, but the novel flavonoid methoxyluteolin inhibits the response entirely, suggesting that it may be developed for treatment of allergic and inflammatory diseases.
肥大细胞（MCs）对过敏反应至关重要，但在炎症过程中也发挥重要作用。神经肽如P物质（SP）和神经降压素（NT）的刺激会导致大量MC分泌颗粒中储存的预形成分子以及新合成的促炎介质释放，包括肿瘤坏死因子、C-X-C基序趋化因子配体8和血管内皮生长因子。在此，我们研究雷帕霉素哺乳动物靶标（mTOR）信号传导在NT或SP刺激培养的人LAD2 MCs中的作用，以及天然黄酮类化合物3',4',5,7-四羟基黄酮（木犀草素）及其新型结构类似物3',4',5,7-四甲氧基黄酮（甲氧基木犀草素）的抑制作用。NT（10 μM）或SP（1 μM）刺激会增加（P < 0.0001）肿瘤坏死因子、C-X-C基序趋化因子配体8和血管内皮生长因子的基因表达（6小时后）和释放（24小时后）。这是通过激活两种mTOR复合物发生的，下游mTORC1底物pp70S6KThr389和mTORC2组分pmTORSer2448的磷酸化（p）蛋白水平升高（P < 0.0001）表明了这一点。使用mTORC1抑制剂雷帕霉素、mTORC1/mTORC2抑制剂托林1或这两种黄酮类化合物对人MCs进行预处理会降低所有三种介质的基因表达和释放（P < 0.0001）。甲氧基木犀草素是比木犀草素或托林1更有效的人MC抑制剂，这意味着除了mTOR复合物外还存在其他MC蛋白靶点。这些发现表明mTOR部分参与MCs的神经肽刺激，但新型黄酮类化合物甲氧基木犀草素完全抑制该反应，表明它可能被开发用于治疗过敏性和炎症性疾病。
