Influence of an altered methylation potential on mRNA methylation and gene expression in HepG2 cells
Influence of an altered methylation potential on mRNA methylation and gene expression in HepG2 cells
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DOI：
10.1016/j.yexcr.2003.12.001
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发表时间：
2004-04-01
影响因子：
3.7
通讯作者：
Kloor, D
中科院分区：
文献类型：
--
作者：
Hermes, M;Osswald, H;Kloor, D
S-腺苷高半胱氨酸（S-adenosylhomocysteine，S-Hcy）是S-腺苷蛋氨酸（S-adenosylmethionine，S-Met）依赖性甲基化反应的副产物和抑制剂，可被S-Hcy水解酶去除。β-Met和β-Hcy的比率，也称为甲基化潜力（NIP），是细胞甲基化状态的代谢指标。在本研究中，我们研究了缺氧和抑制HepG2细胞中的MP-Hcy水解酶的影响。此外，我们还研究了MP偏离对mRNA和DNA甲基化以及所选基因：促红细胞生成素、VEGF-A、Hcy水解酶、亲环蛋白和HIT-1 α表达的影响。在缺氧条件下，MP从53.4 +/-3.3升高到239.4 +/-24.8，这是Hcy水平升高和Hcy水平降低的结果。腺苷-2，3'-二醛抑制α-Hcy水解酶导致MP在常氧和缺氧条件下均减少40倍。缺氧增加促红细胞生成素（2.7倍）和VEGF-A（5倍）mRNA表达。在减少MP促红细胞生成素mRNA表达降低常氧和缺氧70%，而VEGF-A mRNA表达仅减少缺氧条件下的60%。mRNA的表达，HIF-1 α，亲环素，同型半胱氨酸水解酶是不敏感的改变MP。此外，MP降低导致总体mRNA甲基化的高度显著降低。我们的研究结果表明，所研究的基因的mRNA水平差异MP的变化。这意味着转录速率较慢的基因和周转较慢的mRNA对MP的短期变化不敏感。(C)2004年爱思唯尔公司All rights reserved.
S-adenosylhomocysteine (AdoHcy), a by-product and inhibitor of S-adenosylmethionine (AdoMet)-dependent methylation reactions, is removed by AdoHcy hydrolase. The ratio of AdoMet and AdoHcy, also termed methylation potential (NIP), is a metabolic indicator for cellular methylation status. In the present study, we have investigated the influence of hypoxia and inhibition of AdoHcy hydrolase on MP in HepG2 cells. Furthermore, we studied the impact of deviations in MP on mRNA and DNA methylation and the expression of selected genes: erythropoietin, VEGF-A, AdoHcy hydrolase, cyclophilin, and HIT-1alpha.Under hypoxic conditions, the MP raised from 53.4 +/- 3.3 to 239.4 +/- 24.8, which is the result of increased AdoMet and decreased AdoHcy levels. Inhibition of AdoHcy hydrolase by adenosine-2,3'-dialdehyde leads to a 40-fold reduction of the MP under both normoxic and hypoxic conditions. Hypoxia increases erythropoietin (2.7-fold) and VEGF-A (5-fold) mRNA expression. During a reduced MP erythropoietin mRNA expression is lowered under normoxia and hypoxia by 70%, whereas VEGF-A mRNA expression is only reduced under hypoxic conditions by 60%. The mRNA expression of AdoHcy hydrolase, HIF-1alpha, and cyclophilin is insensitive to an altered MP. Furthermore, decreased MP leads to a highly significant decrease in overall mRNA methylation. Our results show that the mRNA levels of the studied genes respond differentially to changes in MP. This implies that genes with a slower transcription rate and mRNAs with a slower turnover are insensitive to short-term changes in MP. (C) 2004 Elsevier Inc. All rights reserved.