Expression of glutathione S-transferases (GSTs) in human colon cells and inducibility of GSTM2 by butyrate
Expression of glutathione S-transferases (GSTs) in human colon cells and inducibility of GSTM2 by butyrate
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DOI：
10.1093/carcin/bgg122
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发表时间：
2003-10-01
期刊：
影响因子：
4.7
通讯作者：
Pool-Zobel, BL
中科院分区：
文献类型：
--
作者：
Ebert, MN;Klinder, A;Pool-Zobel, BL
谷胱甘肽S-转移酶（GST）是一个多基因酶家族，主要参与化学物质的解毒。在动物中，增强的表达由肠道发酵产物介导。其中，丁酸盐在人结肠肿瘤细胞系HT 29中诱导GST P1蛋白表达和GST活性。以下研究的目的是进一步阐明在HT 29中丁酸盐调节的额外结肠GST的诱导，并确定从人结肠直肠组织分离的非转化细胞中的基线表达。用Western blot检测GST蛋白的5个亚基（GSTA 1 - 2-由GST A1-1、A1-2和A2-2组成-GSTM 1、GSTM 2、GSTP 1、GSTT 1），用1-氯-2，4-二硝基苯为底物检测GST活性，用RT-PCR检测GST M2 mRNA的表达。GSTP 1是所有结肠细胞的主要亚基，其次是GSTT 1。从结肠组织中分离的细胞被鉴定为结肠细胞和结肠成纤维细胞，这两者也表达大量水平的GSTM 1和GSTM 2。15个个体的结肠细胞中GST亚基的个体间差异显著，每10（6）个细胞的总GST蛋白差异超过4倍。在HT 29中，丁酸盐显著增强GSTA 1/2（3.5倍）、GSTM 2（在对照中未检测到）、GSTP 1（1.5倍）和GST活性（1.4倍），但不增强GSTM 1或GSTT 1。GSTM 2 mRNA表达在处理24 h（约14倍）和72 h（约8倍）后显著诱导。在结肠成纤维细胞中，丁酸盐（4 mM，72 h）也诱导GSTM 2蛋白（1.7倍）和GST活性（1.4倍）。集落细胞寿命太短，不能用于诱导研究。总之，GST在人结肠细胞中表达具有高度个体间变异性。这表明细胞对异生物质的敏感性存在很大差异。然而，丁酸盐，一种由膳食纤维发酵产生的重要的管腔组分，是GST特别是GSTM 2的有效诱导剂。这表明丁酸盐可能通过增加结肠粘膜的解毒能力而起化学保护作用。
The glutathione S-transferases (GSTs) are a multigene family of enzymes largely involved in the detoxification of chemicals. In animals, enhanced expression is mediated by products of gut fermentation. Of these, butyrate induces GSTP1 protein expression and GST activity in the human colon tumor cell line HT29. The aim of the following investigations was to further elucidate butyrate-modulated induction of additional colonic GSTs in HT29 and to determine baseline expression in non-transformed cells, isolated from human colorectal tissue. We measured five GST protein subunits (GSTA1/2-composed of GST A1-1, A1-2 and A2-2-GSTM1, GSTM2, GSTP1, GSTT1) by western blot, GST activity using 1-chloro-2,4-dinitrobenzene as substrate and GSTM2 mRNA expression with RT-PCR. GSTP1, followed by GSTT1, were major subunits in all colon cells. Cells isolated from colon tissue were identified to be colonocytes and colon fibroblasts, both of which also expressed substantial levels of GSTM1 and GSTM2. The inter-individual variation of GST subunits in coloncytes of 15 individuals was marked, with total GST protein per 10(6) cells differing by more than a factor of four. In HT29, butyrate significantly enhanced GSTA1/2 (3.5-fold), GSTM2 (not detectable in controls), GSTP1 (1.5-fold) and GST activity (1.4-fold), but not GSTM1 or GSTT1. GSTM2 mRNA expression was significantly induced after 24 (approximate to14-fold) and 72 h treatment (approximate to8-fold). In colon fibroblasts, butyrate (4 mM, 72 h) also induced GSTM2 protein (1.7-fold) and GST activity (1.4-fold). Colonocytes were too short lived to be used for inducibility studies. In conclusion, GSTs are expressed with high inter-individual variability in human colonocytes. This points to large differences in cellular susceptibility to xenobiotics. However, butyrate, an important luminal component produced from fermentation of dietary fibers, is an efficient inducer of GSTs and especially of GSTM2. This indicates that butyrate may act chemoprotectively by increasing detoxification capabilities in the colon mucosa.