Relationship between acetaldehyde levels and cell survival in ethanol-metabolizing hepatoma cells
Relationship between acetaldehyde levels and cell survival in ethanol-metabolizing hepatoma cells
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DOI：
10.1053/jhep.2002.32668
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发表时间：
2002-05-01
期刊：
影响因子：
13.5
通讯作者：
Tuma, DJ
中科院分区：
文献类型：
--
作者：
Clemens, DL;Forman, A;Tuma, DJ
我们已经创造了许多重组Hep G2细胞系，被称为VA细胞，它们组成性地表达乙醇脱氢酶。乙醇被VA细胞氧化导致乙醛的产生和积累，烟酰胺腺嘌呤二核苷酸急剧增加，降低(NADH)/烟酰胺腺嘌呤二核苷酸（NAD+）比例（氧化还原状态）。据信，乙醛的产生和肝细胞氧化还原状态的增加是许多与酒精性肝病相关的功能障碍的原因。当VA细胞在乙醇中培养时，我们观察到细胞积累显著减少。这种减少在更有效地代谢乙醇的细胞中更为明显。酒精脱氢酶活性的抑制消除了这种还原，表明这种功能障碍需要乙醇氧化。随后的研究表明，这种乙醇氧化介导的细胞积累减少是细胞毒性和DNA合成受损的结果。为了将细胞氧化还原状态的增加与乙醛生产分离，在异丙醇存在下培养VA细胞。异丙醇的氧化引起类似的氧化还原变化，但异丙醇氧化的代谢副产物是丙酮。VA细胞对异丙醇的代谢导致细胞数量很少减少。此外，用醛脱氢酶抑制剂氰酰胺处理乙醇代谢的VA细胞，增加了乙醛水平，导致细胞数量进一步减少。总之，这些研究表明，暴露于乙醛引起细胞毒性，以及乙醇氧化介导的细胞数量减少。
We have created a number of recombinant Hep G2 cell lines, designated VA cells, that constitutively express alcohol dehydrogenase. Oxidation of ethanol by the VA cells results in the production and accumulation of acetaldehyde, and a dramatic increase in the nicotinamide adenine dinucleotide, reduced (NADH)/nicotinamide adenine dinucleotide (NAD+) ratio (redox-state). It is believed that production of acetaldehyde, and the increase in the redox-state of hepatocytes, are responsible for many of the dysfunctions associated with alcoholic liver disease. When the VA cells were cultured in the presence of ethanol, we observed a dramatic reduction in cell accumulation. This reduction was more pronounced in cells that metabolized ethanol more efficiently. Inhibition of alcohol dehydrogenase activity abolished this reduction, demonstrating that ethanol oxidation was required for this dysfunction. Subsequent investigations indicated that this ethanol oxidation-mediated reduction in cell accumulation was the result of both cytotoxicity and impaired DNA synthesis. To dissociate the increase in the cellular redox-state from acetaldehyde production, VA cells were cultured in the presence of isopropanol. The oxidation of isopropanol results in similar redox changes, but the metabolic by-product of isopropanol oxidation is acetone. The metabolism of isopropanol by VA cells resulted in very little reduction in cell number. Furthermore, treatment of ethanol-metabolizing VA cells with the aldehyde dehydrogenase inhibitor, cyanamide, increased the levels of acetaldehyde and resulted in an additional reduction in cell number. In conclusion, these studies indicated that exposure to acetaldehyde caused cytotoxicity, as well as the ethanol oxidation-mediated reduction in cell number.