Louis C A, Reichner J S, Henry W L, Mastrofrancesco B, Gotoh T, Mori M, Albina J E
Department of Surgery, Rhode Island Hospital, Providence, USA.
Am J Physiol. 1998 Mar;274(3):R775-82. doi: 10.1152/ajpregu.1998.274.3.R775.
Experiments were performed to identify arginase isoforms expressed in primary and transformed rodent macrophages and to determine the molecular mechanisms for the previously observed increase in arginase activity in macrophages cultured in hypoxia or anoxia. Results demonstrate the following: 1) mRNA and protein for hepatic-type AI arginase are expressed in primary cultures of rat and mouse peritoneal macrophages and are enhanced seven- and nine-fold, respectively, by lipopolysaccharide (LPS). 2) mRNA for extrahepatic-type AII arginase is constitutively expressed in mouse, but not rat, peritoneal macrophages and is detected in RAW264.7 cells after LPS treatment; neither J774A.1 nor P388D1 cells contain arginase mRNA. 3) AI arginase mRNA, arginase activity in cell lysates, and L-arginine flux through arginase in intact cells are all increased in rat wound-derived and mouse peritoneal macrophages by hypoxic or anoxic culture; AII arginase mRNA is, in contrast, suppressed > 50% by O2 deprivation. 4) Expression of the L-arginine transporter mCAT-2 is increased greater than twofold by reduced O2 culture. These results demonstrate substantial variability in arginase isoform expression among primary and transformed rodent macrophages. They also identify AI and AII arginase and the mCAT-2 L-arginine transporter as O2-regulated genes.
开展实验以鉴定在原代和转化的啮齿动物巨噬细胞中表达的精氨酸酶同工型，并确定先前观察到的在缺氧或无氧条件下培养的巨噬细胞中精氨酸酶活性增加的分子机制。结果表明如下：1）肝型AI精氨酸酶的mRNA和蛋白在大鼠和小鼠腹膜巨噬细胞的原代培养物中表达，并且分别被脂多糖（LPS）增强7倍和9倍。2）肝外型AII精氨酸酶的mRNA在小鼠而非大鼠的腹膜巨噬细胞中组成性表达，并且在LPS处理后的RAW264.7细胞中被检测到；J774A.1细胞和P388D1细胞均不含有精氨酸酶mRNA。3）在大鼠伤口来源的和小鼠腹膜巨噬细胞中，缺氧或无氧培养均使AI精氨酸酶mRNA、细胞裂解物中的精氨酸酶活性以及完整细胞中通过精氨酸酶的L-精氨酸通量增加；相比之下，缺氧使AII精氨酸酶mRNA表达降低>50%。4）低氧培养使L-精氨酸转运蛋白mCAT-2的表达增加超过两倍。这些结果表明原代和转化的啮齿动物巨噬细胞之间精氨酸酶同工型表达存在显著差异。它们还确定AI和AII精氨酸酶以及mCAT-2 L-精氨酸转运蛋白为氧调节基因。
