Control of extracellular cysteine/cystine redox state by HT-29 cells is independent of cellular glutathione
Control of extracellular cysteine/cystine redox state by HT-29 cells is independent of cellular glutathione
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DOI：
10.1152/ajpregu.00195.2007
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发表时间：
2007-09-01
影响因子：
2.8
通讯作者：
Jones, Dean P.
中科院分区：
文献类型：
--
作者：
Anderson, Corinna L.;Iyer, Smita S.;Jones, Dean P.
人类细胞系将培养基中半胱氨酸/胱氨酸（Cys/CySS）偶对的氧化还原态（Eh）调节到约- 80 mV，与人血浆中Cys/CySS的平均Eh值相似。CySS /CySS调节细胞外Eh的机制尚不清楚，但GSH以与组织GSH浓度成正比的速率从组织中释放出来，这种释放的GSH可以与CySS反应，有助于维持这种平衡。本研究旨在确定细胞GSH的消耗是否会改变细胞外Cys/CySS Eh的调节。通过抑制l -丁硫氨酸-[S， R]-亚砜亚胺的合成来降低HT- 29细胞的GSH，对细胞外CySS的还原速率没有影响，以达到培养基中CySS /CySS的稳定Eh。限制培养基中的Cys和CySS也显著降低了细胞GSH，但对细胞外Cys/CySS Eh没有显著影响。添加CySS后，细胞外Cys/CySS Eh在4 h时接近- 80 mV，而细胞内GSH和细胞外GSH/GSSG Eh恢复较慢。总之，这些结果表明HT- 29细胞具有通过独立于细胞GSH的机制调节细胞外Cys/CySS Eh的能力。结果表明，在细胞外Cys/CySS Eh的调控中，Cys和CySS和/或膜氧化还原酶的转运系统可能比细胞GSH更重要。
Human cell lines regulate the redox state ( Eh) of the cysteine/cystine ( Cys/CySS) couple in culture medium to approximately - 80 mV, a value similar to the average Eh for Cys/CySS in human plasma. The mechanisms involved in regulation of extracellular Eh of Cys/CySS are not known, but GSH is released from tissues at rates proportional to tissue GSH concentration, and this released GSH could react with CySS to contribute to maintenance of this balance. The present study was undertaken to determine whether depletion of cellular GSH alters regulation of extracellular Cys/CySS Eh. Decrease of GSH in HT- 29 cells by inhibiting synthesis with L-buthionine-[ S, R]- sulfoximine showed no effect on the rate of reduction of extracellular CySS to achieve a stable Eh for Cys/CySS in the culture medium. Limiting Cys and CySS in the culture medium also substantially decreased cellular GSH but resulted in no significant effect on extracellular Cys/CySS Eh. Addition of CySS to these cells showed that extracellular Cys/CySS Eh approached - 80 mV at 4 h while cellular GSH and extracellular GSH/GSSG Eh recovered more slowly. Together, these results show that HT- 29 cells have the capacity to regulate the extracellular Cys/CySS Eh by mechanisms that are independent of cellular GSH. The results suggest that transport systems for Cys and CySS and/or membranal oxidoreductases could be more important than cellular GSH in regulation of extracellular Cys/CySS Eh.