German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany.
Mol Nutr Food Res. 2010 May;54(5):652-60. doi: 10.1002/mnfr.200900462.
Based on the observation that 3 months alpha-tocopherol supplementation caused an up-regulation of the mRNA of vesicular transport proteins in livers of mice, the functional relevance was investigated in RBL-2H3 cells, a model for mast cell degranulation. In total, 24 h incubation with 100 muM alpha-tocopherol enhanced the basal and phorbol-12-myristyl-13-acetate/ionomycin-stimulated release of beta-hexosaminidase and cathepsin D as measured by enzymatic analysis as well as Western blotting and immunocytochemistry, respectively. beta-Tocopherol exerted the same effect, whereas alpha-tocopheryl phosphate and trolox were inactive, indicating that both the side chain and the 6-OH group at the chroman ring are essential for activation of degranulation. alpha-Tocopherol did not induce mRNA expression of soluble NSF-attachment protein receptor (soluble N-ethylmaleimide-sensitive factor-attachment protein receptor) proteins, such as N-ethylmaleimide sensitive fusion protein, complexin-2, SNAP23 or syntaxin-3, in the RBL-2H3 cell model. In view of the well known alpha-tocopherol-mediated activation of protein phosphatases, which regulate soluble NSF-attachment protein receptor activities by dephosphorylation, underlying mechanisms are discussed in terms of preventing oxidative inactivation of protein phosphatases and so far unknown functions in certain membrane domains.
基于观察到 3 个月的α-生育酚补充剂会导致小鼠肝脏中囊泡运输蛋白的 mRNA 上调，因此在 RBL-2H3 细胞中研究了其功能相关性，RBL-2H3 细胞是肥大细胞脱粒的模型。总的来说，用 100μM 的α-生育酚孵育 24 小时，通过酶分析以及 Western blot 和免疫细胞化学，分别增强了基础和佛波醇 12-肉豆蔻酸 13-乙酸/离子霉素刺激的β-己糖胺酶和组织蛋白酶 D 的释放。β-生育酚也具有相同的作用，而α-生育酚磷酸酯和 Trolox 则没有活性，表明侧链和色满环上的 6-OH 基团对于脱粒的激活都是必需的。α-生育酚在 RBL-2H3 细胞模型中不会诱导可溶性 NSF 附着蛋白受体（可溶性 N-乙基马来酰亚胺敏感因子附着蛋白受体）蛋白的 mRNA 表达，如 N-乙基马来酰亚胺敏感融合蛋白、复合蛋白-2、SNAP23 或 syntaxin-3。鉴于众所周知的α-生育酚介导的蛋白磷酸酶激活，通过去磷酸化调节可溶性 NSF 附着蛋白受体的活性，因此在某些膜域中，讨论了其潜在的机制，包括防止蛋白磷酸酶的氧化失活和迄今为止未知的功能。
