Structure-effect relationship in the down-regulation of glutaminase in cultured human cells by phenylarsenic compounds
Structure-effect relationship in the down-regulation of glutaminase in cultured human cells by phenylarsenic compounds
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DOI：
10.1016/j.tox.2009.01.020
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发表时间：
2009-04-28
期刊：
影响因子：
4.5
通讯作者：
Ochi, Takafumi
中科院分区：
文献类型：
--
作者：
Kita, Kayoko;Sato, Motohiro;Ochi, Takafumi
在日本神栖发生中毒事件后，在用作饮用水的地下水中检测到二苯胂酸[DPAA（V）]。一种通过对来自培养的人细胞的蛋白质进行高通量分析来确定DPAA（V）的靶分子的方法证明了谷氨酰胺酶C（GAC）的下调。GAC是肾型转氨酶（KGA）基因的剪接变体，具有磷酸活化转氨酶（PAG）的酶活性。为了深入了解神鼠砷中毒的机制，研究了各种砷化合物，包括在地下水[DPAA（V）]、苯胂酸[PAA（V）]和双（二苯基胂）氧化物[BDPAO（III）]和大米（苯甲基胂酸[PMAA（V）]）中检测到的砷化合物，对GAC和PAG活性表达的影响。当培养的人HepG 2细胞与砷剂共同孵育24 h时，五价苯砷形式的PAA（V）、PMAA（V）和DPAA（V）均以浓度依赖的方式抑制GAC蛋白的表达和PAG活性。另一方面，三价苯砷形式的BDPAO（III）对GAC和PAG没有抑制作用。此外，三价苯砷化合物，如DPAA（V）[DPA-GS（III）]和三苯基砷[TPA（III）]的谷胱甘肽（GSH）缀合物，无机砷，iAs（V）和iAs（III），以及无机砷的甲基化代谢物，二甲基胂酸[DMA（V）]和二甲基胂酸[DMA（III）]，对转氨酶没有抑制作用。同样地，DPAA（V）、PAA（V）和PMAA（V）的羟基的甲基取代基、二苯基甲基氧化胂[DPMAO（V）]和苯基二甲基氧化胂[PDMAO（V）]没有任何抑制作用。这些结果表明，具有苯基和羟基的五价砷化合物在抑制转氨酶方面是有效的。此外，只有在Kamisu中检测到的砷剂才能有效抑制转氨酶，这一事实为Kamisu砷中毒的原因提供了见解。(c)2009爱思唯尔爱尔兰有限公司保留所有权利。
Diphenylarsinic acid [DPAA(V)] was detected in ground water used as drinking water after a poisonous incident in Kamisu, Japan. An approach to define the target molecules of DPAA(V) with a high throughput analysis of proteins from cultured human cells demonstrated down-regulation of glutaminase C (GAC). GAC is a splicing variant of the kidney-type glutaminase (KGA) gene and has the enzyme activity of phosphate-activated glutaminase (PAG). To gain some insights into the mechanism of arsenic intoxication in Kamisu, the effects of various arsenic compounds, including arsenicals that were detected in ground water [DPAA(V)], phenylarsonic acid [PAA(V)] and bis(diphenylarsine)oxide [BDPAO(III)]) and rice (phenylmethylarsinic acid [PMAA(V)], were investigated for the expression of GAC and PAG activity. When cultured human HepG2 cells were incubated with arsenicals for 24 h, the pentavalent phenylarsenic form of PAA(V) and PMAA(V) as well as DPAA(V) suppressed the expression of GAC protein and PAG activity in a concentration-dependent manner. On the other hand, the trivalent phenylarsenic form of BDPAO(III) had no suppressive effect on GAC and PAG. In addition, trivatent phenylarsenic compounds, such as the glutathione (GSH) conjugate of DPAA(V) [DPA-GS (III)] and triphenylarsine [TPA(III)], and the inorganic arsenics, iAs(V) and iAs(III), and methylated metabolites of inorganic arsenics, dimethylarsinic acid [DMA(V)] and dimethylarsinous acid [DMA(ill)], had no suppressive effect on glutaminase. Likewise, methyl substituents of the hydroxyl groups of DPAA(V), PAA(V) and PMAA(V), diphenylmethylarsine oxide [DPMAO(V)] and phenyldimethylarsine oxide [PDMAO(V)], did not have any suppressive effects. These results suggest that pentavalent arsenic compounds with both phenyl groups and hydroxyl groups are effective in the suppression of glutaminase. In addition, the fact that it was only the arsenicals detected in Kamisu that were effective in suppressing glutaminase provides insights into the cause of the arsenic intoxication at Kamisu. (c) 2009 Elsevier Ireland Ltd. All rights reserved.