Brungs M, Rådmark O, Samuelsson B, Steinhilber D
Department of Pharmaceutical Chemistry, University of Tübingen, Germany.
Proc Natl Acad Sci U S A. 1995 Jan 3;92(1):107-11. doi: 10.1073/pnas.92.1.107.
5-Lipoxygenase (5-LO; EC 1.13.11.34) activity in the human monocytic cell line Mono Mac 6 was upregulated by combined treatment with transforming growth factor beta 1 (TGF-beta) and 1,25-dihydroxyvitamin D3 (VD3). In undifferentiated cells, 5-LO enzyme activity was undetectable. After the addition of TGF-beta plus VD3, the activity of intact cells was 800 ng per 10(6) cells--500 times more than the assay detection limit. Also 5-LO protein and mRNA expression were induced > 128-fold and 64-fold, respectively, as compared to undifferentiated cells. Both TGF-beta and VD3 were required for these prominent responses. Either agent alone gave small amounts of 5-LO protein and mRNA but very low 5-LO activities. After the addition of TGF-beta and VD3, the induction of 5-LO protein was obvious after 1 day, but the increase in activity was delayed and did not appear until the second day. Pretreatment of cells with TGF-beta or VD3 alone for 2 days led to 5-LO protein expression but very low enzyme activity. Addition of the lacking second inducer was required for full induction of 5-LO protein expression and for upregulation of enzyme activity. Partial purification of 5-LO from Mono Mac 6 cells and recombination with soluble cellular proteins from different sources indicated the presence of cytosolic factors that affect the activity of 5-LO.
在人单核细胞系Mono Mac 6中，5-脂氧合酶（5-LO；EC 1.13.11.34）的活性通过转化生长因子β1（TGF-β）和1,25-二羟基维生素D3（VD3）联合处理而上调。在未分化细胞中，检测不到5-LO酶活性。添加TGF-β加VD3后，完整细胞的活性为每10(6)个细胞800 ng，比检测限高500倍。与未分化细胞相比，5-LO蛋白和mRNA表达分别诱导增加了>128倍和64倍。这些显著反应需要TGF-β和VD3两者。单独使用任何一种试剂都只能产生少量的5-LO蛋白和mRNA，但5-LO活性非常低。添加TGF-β和VD3后，5-LO蛋白的诱导在1天后明显，但活性增加延迟，直到第二天才出现。单独用TGF-β或VD3预处理细胞2天会导致5-LO蛋白表达，但酶活性非常低。需要添加缺失的第二种诱导剂才能完全诱导5-LO蛋白表达并上调酶活性。从Mono Mac 6细胞中对5-LO进行部分纯化，并与来自不同来源的可溶性细胞蛋白重组，表明存在影响5-LO活性的细胞溶质因子。
