Species differences in expression pattern of arginase isoenzymes and differential effects of arginase inhibition on collagen synthesis in human and rat pulmonary fibroblasts
Species differences in expression pattern of arginase isoenzymes and differential effects of arginase inhibition on collagen synthesis in human and rat pulmonary fibroblasts
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DOI：
10.1007/s00210-009-0489-6
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发表时间：
2010-04-01
影响因子：
3.6
通讯作者：
Racke, K.
中科院分区：
文献类型：
--
作者：
Warnken, M.;Haag, S.;Racke, K.
精氨酸酶在炎症性和纤维化呼吸道疾病的不同动物模型中被证明是上调的。由于精氨酸酶提供L-鸟氨酸的前体，L-脯氨酸是胶原合成的重要底物，因此精氨酸酶可能是气道重塑的关键酶。本研究旨在研究精氨酸酶同工酶在大鼠和人肺成纤维细胞中的表达，以及精氨酸酶抑制对胶原合成的影响。在原代培养的大鼠气管和肺成纤维细胞中可检测到精氨酸酶I和精氨酸酶II的mRNA，其中精氨酸酶I是主要的同工酶。而在人肺成纤维细胞(原代细胞和不同细胞系)中，精氨酸酶I的mRNA水平处于或低于检测下限，而精氨酸酶II的mRNA水平明显高于大鼠肺成纤维细胞。大鼠气管和肺成纤维细胞的精氨酸酶活性在20~30mU/mg蛋白之间，而人肺成纤维细胞的精氨酸酶活性低于检测下限(2.5mU/mg蛋白)。在无脯氨酸培养的大鼠气管和肺成纤维细胞中，N-omega-羟基或L-精氨酸对精氨酸酶的抑制可使I型胶原的基础积累量减少约1/3(用免疫印迹法测定)，并大大减弱转化生长因子-β1(TGF1)诱导的胶原积聚的增加，而基础和TGF1诱导的人肺成纤维细胞胶原积聚不受精氨酸酶抑制的影响。总而言之，精氨酸酶同工酶显示了物种特有的表达模式。在大鼠成纤维细胞中，精氨酸酶是胶原合成的主要同工酶，而在人成纤维细胞中则不是，精氨酸酶是唯一表达的同工酶。
Arginase was shown to be up-regulated in different animal models of inflammatory and fibrotic airway diseases. Since arginase provides l-ornithine, one precursor for l-proline, an essential substrate for collagen synthesis, it has been suggested that arginase might be a key enzyme in airway remodelling. The present study aimed to characterize expression of arginase isoenzymes in rat and human pulmonary fibroblasts, and to test whether arginase inhibition affects collagen synthesis. In primary rat tracheal and lung fibroblasts, mRNA for arginase I and II could be detected, with arginase I as predominant isoenzyme. In contrast, in human lung fibroblasts (primary cells and different cells lines) mRNA levels for arginase I were at or below detection limit whereas arginase II mRNA was markedly higher than in rat pulmonary fibroblasts. Arginase activity in rat tracheal and lung fibroblasts was between 20 and 30 mU/mg protein, but was below detection limit (2.5 mU/mg) in human lung fibroblasts. In rat tracheal and lung fibroblasts cultured in proline-free medium, arginase inhibition by N-omega-hydroxy-nor-l-arginine caused a reduction by about one-third of basal collagen I accumulation (determined by western blot analysis) and largely attenuated transforming growth factor beta 1 (TGF-(1))-induced increase in collagen accumulation, whereas basal and TGF-(1)-induced collagen accumulation by human lung fibroblasts was not affected by arginase inhibition. In conclusion, arginase isoenzymes reveal a species specific expression pattern. Arginase contributes significantly to l-proline supply for collagen synthesis in rat fibroblasts, in which arginase I is the predominant isoenzyme, but not in human fibroblasts, in which arginase II is the only isoenzyme expressed.