Yegorova Svitlana, Yegorov Oleg, Lou Marjorie F
Department of Veterinary and Biomedical Sciences, University of Nebraska-Lincoln, 134 VBS, Fair St./East Campus Loop, 68583-0905, USA.
Exp Eye Res. 2006 Oct;83(4):783-92. doi: 10.1016/j.exer.2006.03.018. Epub 2006 May 19.
Thioredoxin (Trx) is one of the major redox-regulating proteins. It catalyzes dithiol/disulfide exchange reactions and displays many unique intracellular and extracellular activities thereby controlling multiple mammalian cell functions. In the present study we examine the effect of exogenous Trx on the expression of several antioxidant genes in human lens epithelial (HLE B3) cells. mRNA levels for gene expression were monitored by RT-PCR and real-time PCR while protein levels were measured by western blot analysis. We have found that recombinant human Trx (hTrx)-treated HLE B3 cells have a simultaneous increase in mRNA expressions of mitochondrial manganese superoxide dismutase (MnSOD), thioltranferase 1 (TTase 1) or glutaredoxin 1 (Grx1), mitochondrial thioltransferase (TTase 2) or glutaredoxin 2 (Grx2), and thioredoxin peroxidase IV (Prx IV). The increased MnSOD and TTase 1 mRNA expressions were accompanied with their respective increases in protein levels. Other antioxidant genes, including Cu/ZnSOD, catalase, glutathione peroxidase 1 (GPx1), thioredoxin reductase 1 (TrxR1), thioredoxin peroxidase III (Prx III), and gamma-glutamyl cysteine synthetase were not affected. The ability of Trx to induce selectively these antioxidant genes in the absence of oxidative stress suggest a cytokine/growth factor-like new physiological role of hTrx in HLE B3 cells. Our data also provide evidence of a strong antioxidant defense system in HLE B3 cells that can be activated by extracellular hTrx, as well as of a possible link between the thioredoxin (Trx) and glutathione (GSH) redox regulating systems in these cells.
硫氧还蛋白（Trx）是主要的氧化还原调节蛋白之一。它催化二硫醇/二硫化物交换反应，并表现出许多独特的细胞内和细胞外活性，从而控制多种哺乳动物细胞功能。在本研究中，我们检测了外源性Trx对人晶状体上皮（HLE B3）细胞中几种抗氧化基因表达的影响。通过逆转录聚合酶链反应（RT-PCR）和实时定量PCR监测基因表达的mRNA水平，同时通过蛋白质印迹分析测量蛋白质水平。我们发现，经重组人Trx（hTrx）处理的HLE B3细胞中线粒体锰超氧化物歧化酶（MnSOD）、硫醇转移酶1（TTase 1）或谷氧还蛋白1（Grx1）、线粒体硫醇转移酶（TTase 2）或谷氧还蛋白2（Grx2）以及硫氧还蛋白过氧化物酶IV（Prx IV）的mRNA表达同时增加。MnSOD和TTase 1 mRNA表达的增加伴随着它们各自蛋白质水平的升高。其他抗氧化基因，包括铜/锌超氧化物歧化酶（Cu/ZnSOD）、过氧化氢酶、谷胱甘肽过氧化物酶1（GPx1）、硫氧还蛋白还原酶1（TrxR1）、硫氧还蛋白过氧化物酶III（Prx III）和γ-谷氨酰半胱氨酸合成酶则未受影响。Trx在无氧化应激情况下选择性诱导这些抗氧化基因的能力表明hTrx在HLE B3细胞中具有类似细胞因子/生长因子的新生理作用。我们的数据还提供了证据，证明HLE B3细胞中存在一个强大的抗氧化防御系统，该系统可被细胞外hTrx激活，以及这些细胞中硫氧还蛋白（Trx）和谷胱甘肽（GSH）氧化还原调节系统之间可能存在的联系。
