Metabolism of Inorganic Arsenic in Intestinal Epithelial Cell Lines
Metabolism of Inorganic Arsenic in Intestinal Epithelial Cell Lines
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DOI：
10.1021/tx300385y
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发表时间：
2012-11-01
影响因子：
4.1
通讯作者：
Devesa, V.
中科院分区：
文献类型：
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作者：
Calatayud, M.;Velez, D.;Devesa, V.
本研究评估了无机砷（iAs）[As（III）和As（V）]在人体肠细胞中的代谢，作为细胞类型，分化阶段，用于细胞生长的支持类型和暴露时间的函数。此外，评估砷（+3氧化态）甲基转移酶（AS 3 MT）的mRNA表达。为此，Caco-2（吸收型）和HT 29-MTX（杯型）细胞暴露在不同的分化阶段（5，15，和21天后播种）与不同浓度的As（III）和As（V）（1和10 μ M）和曝光时间（24，48，和72小时），使用多孔板或Transwell。结果表明，两种细胞系在所有分化阶段和所有培养条件下均表达AS 3 MT。Caco-2细胞能够代谢iAs，As（HI）代谢大于As（V）。代谢取决于分化阶段，分化细胞暴露48小时后（接种后15天）达到36%，单甲基化物质为主要代谢产物。细胞内部的分析表明，代谢产物主要以三价形式存在。支持物的类型也是一个重要因素，多孔板中的代谢高于Transwell（36 +/- 6% vs 11 +/- 3%）。暴露于iAs后，在HT 29-MTX细胞中未检测到单甲基化砷物质（MMA）或二甲基化砷物质（DMA），这可能是因为大多数iAs保留在粘液层中，不内化。这些结果表明，肠道是一个器官，可能参与了系统前代谢的iAs。此外，iAs转化为更具毒性的物种表明需要研究该物种对肠上皮的影响。
This study evaluates the metabolism of inorganic arsenic (iAs) [As(III) and As(V)] in human intestinal cells as a function of cell type, differentiation stage, type of support used for cell growth, and exposure time. Additionally, mRNA expression of arsenic (+3 oxidation state) methyltransferase (AS3MT) was evaluated. For this purpose, Caco-2 (absorptive type) and HT29-MTX (goblet type) cells were exposed at various stages of differentiation (5, 15, and 21 days post-seeding) with different concentrations of As(III) and As(V) (1 and 10 mu M) and exposure times (24, 48, and 72 h), using multiwell plates or Transwells. The results show that both cell lines express AS3MT at all stages of differentiation and in all culture conditions. Caco-2 cells are capable of metabolizing iAs, As(HI) metabolism being greater than that observed for As(V). Metabolism depends on the stage of differentiation, reaching 36% after 48 h of exposure of differentiated cells (15 days post-seeding), with the monomethylated species as the major metabolite. Analysis of the cell interior shows that the metabolites are present predominantly in trivalent form. The type of support is also an important factor, metabolism being greater in multiwell plates than in Transwells (36 +/- 6% vs 11 +/- 3%). Neither monomethylated arsenic species (MMA) nor dimethylated arsenic species (DMA) are detected in HT29-MTX cells after exposure to iAs, possibly because most of the iAs is retained in the mucus layer and does not internalize. These results show that the intestine is an organ that may take part in presystemic metabolism of iAs. Moreover, the transformation of iAs into more toxic species indicates the need to study the effects of this species on the intestinal epithelium.