Granulocyte-macrophage colony-stimulating factor increases L-arginine transport through the induction of CAT2 in bone marrow-derived macrophages
Granulocyte-macrophage colony-stimulating factor increases L-arginine transport through the induction of CAT2 in bone marrow-derived macrophages
复制标题
DOI：
10.1152/ajpcell.00520.2005
复制
发表时间：
2006-05-01
影响因子：
5.5
通讯作者：
Bertran, J
中科院分区：
文献类型：
--
作者：
Martín, L;Comalada, M;Bertran, J
L-精氨酸转运对于巨噬细胞活化至关重要，因为它为关键酶一氧化氮合酶2和辅酶I提供底物。这些酶分别参与巨噬细胞的经典和替代活化。巨噬细胞的经典活化由I型细胞因子诱导，并且替代活化由II型细胞因子诱导。粒细胞巨噬细胞集落刺激因子（GMCSF），除了诱导巨噬细胞的增殖和分化，激活辅酶I，但其作用L-精氨酸转运是未知的。我们研究了小鼠原代骨髓源性巨噬细胞（BMM）中具有活性的L-精氨酸转运蛋白，并检查了GM-CSF处理对转运活性的影响。在基础条件下，L-精氨酸主要通过y（+）L系统进入（> 75%）。其余的转运由系统y（+）（< 10%）和扩散组分（10-15%）解释。对GM-CSF处理的响应，转运活性主要通过系统y（+）增加（> 10倍），占总L-精氨酸转运的约40%。y（+）活性的增加与阳离子氨基酸转运体（CAT）-2 mRNA和蛋白的升高相关。此外，GM-CSF诱导的酶活性和L-精氨酸的转化为鸟氨酸，瓜氨酸，谷氨酸，脯氨酸，和多胺的增加。从CAT 2基因敲除小鼠获得的BMM通过增加γ-淀粉酶活性和CAT 1 mRNA的表达对GM-CSF作出反应，CAT 1 mRNA也编码系统γ（+）活性。尽管如此，CAT 1活性的增加仅部分补偿CAT 2的缺乏，L-精氨酸代谢几乎没有受到刺激。我们的结论是，BMM目前主要是γ（+）L活性，并在响应GM-CSF，L-精氨酸转运增加通过CAT 2，从而增加这种氨基酸的细胞的可用性。
L-Arginine transport is crucial for macrophage activation because it supplies substrate for the key enzymes nitric oxide synthase 2 and arginase I. These enzymes participate in classic and alternative activation of macrophages, respectively. Classic activation of macrophages is induced by type I cytokines, and alternative activation is induced by type II cytokines. The granulocyte macrophage colony-stimulating factor ( GMCSF), in addition to inducing proliferation and differentiation of macrophages, activates arginase I, but its action on L-arginine transport is unknown. We studied the L-arginine transporters that are active in mouse primary bone marrow-derived macrophages (BMM) and examined the effect of GM-CSF treatment on transport activities. Under basal conditions, L-arginine entered mainly through system y(+)L (> 75%). The remaining transport was explained by system y(+)(< 10%) and a diffusion component (10-15%). In response to GM-CSF treatment, transport activity increased mostly through system y(+)(> 10-fold), accounting for about 40% of the total L-arginine transport. The increase in y(+) activity correlated with a rise in cationic amino acid transporter (CAT)-2 mRNA and protein. Furthermore, GM-CSF induced an increase in arginase activity and in the conversion of L-arginine to ornithine, citrulline, glutamate, proline, and polyamines. BMM obtained from CAT2-knockout mice responded to GM-CSF by increasing arginase activity and the expression of CAT1 mRNA, which also encodes system y(+) activity. Nonetheless, the increase in CAT1 activity only partially compensated the lack of CAT2 and L-arginine metabolism was hardly stimulated. We conclude that BMM present mainly y(+) L activity and that, in response to GM-CSF, L-arginine transport augments through CAT2, thereby increasing the availability of this amino acid to the cell.