Rishikof D C, Krupsky M, Goldstein R H
Pulmonary Center and the Department of Biochemistry at the Boston University School of Medicine and the Boston VA Medical Center, Boston, MA, USA.
Biochim Biophys Acta. 1998 Oct 21;1405(1-3):155-60. doi: 10.1016/s0167-4889(98)00104-9.
Prostaglandin E2 (PGE2) is an inflammatory mediator capable of regulating fibroblast cell proliferation, matrix protein production, and system A amino acid transport. System x-c amino acid transport is regulated by electrophilic agents and oxygen. The effect of PGE2 on the x-c system transport of cystine and the synthesis of glutathione by human lung fibroblasts was examined. Preincubation of fibroblast cultures with PGE2 decreased cystine uptake by 42%. Kinetic studies revealed a 42% decrease in the Vmax of the x-c system transporter in PGE2-treated fibroblasts; however, the apparent Km was not affected. The glutathione content of PGE2-treated fibroblasts was decreased by up to 25% of control. These results demonstrate that system x-c transport of cystine is regulated by PGE2 and suggest that the limited availability of intracellular cysteine inhibited glutathione synthesis.
前列腺素E2（PGE2）是一种炎症介质，能够调节成纤维细胞增殖、基质蛋白生成以及系统A氨基酸转运。系统x-c氨基酸转运受亲电试剂和氧气调节。研究了PGE2对人肺成纤维细胞x-c系统胱氨酸转运及谷胱甘肽合成的影响。用PGE2预孵育成纤维细胞培养物可使胱氨酸摄取减少42%。动力学研究显示，PGE2处理的成纤维细胞中x-c系统转运体的Vmax降低了42%；然而，表观Km未受影响。PGE2处理的成纤维细胞中谷胱甘肽含量最多降低了对照的25%。这些结果表明，胱氨酸的系统x-c转运受PGE2调节，提示细胞内半胱氨酸可用性受限抑制了谷胱甘肽合成。
