Methylenetetrahydrofolate reductase C677T polymorphism, folic acid and riboflavin are important determinants of genome stability in cultured human lymphocytes
Methylenetetrahydrofolate reductase C677T polymorphism, folic acid and riboflavin are important determinants of genome stability in cultured human lymphocytes
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DOI：
10.1093/jn/134.1.48
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发表时间：
2004-01-01
影响因子：
4.2
通讯作者：
Fenech, M
中科院分区：
文献类型：
--
作者：
Kimura, M;Umegaki, K;Fenech, M
我们检验了这样一个假设：亚甲基四氢叶酸还原酶（MTHFR）C677T多态性、叶酸缺乏和核黄素缺乏，无论是独立作用还是相互作用，都是9天人类淋巴细胞培养中基因组稳定性、细胞死亡、细胞增殖和同型半胱氨酸（Hcy）浓度的重要决定因素。7名野生型（CC）和7名突变型（TT）纯合子的淋巴细胞在核黄素缺乏和充足（0和500 nmol/L）以及叶酸缺乏和充足（20和100 nmol/L）的四种可能组合下培养，L - 甲硫氨酸浓度恒定为50 μmol/L。TT细胞的活细胞生长比CC细胞高25%（P < 0.05），在100 nmol/L叶酸条件下比在20 nmol/L叶酸条件下高32%（P = 0.002）。采用综合胞质分裂阻滞微核试验来测量微核（MNi；染色体断裂和丢失的标志物）、核质桥（NPB；染色体重排的标志物）和核芽（NBUD，基因扩增的标志物）。TT细胞的MNi水平比CC细胞高21%（P < 0.05），在高叶酸培养基中比在低叶酸培养基中低42%（P < 0.0001）。TT细胞的NBUD水平比CC细胞低27%（P < 0.05），在高叶酸培养基中比在低叶酸培养基中低45%（P < 0.0001）。在叶酸缺乏条件下（20 nmol/L叶酸培养基），高核黄素浓度（500 nmol/L）使NBUD水平增加25%（与0 nmol/L核黄素相比；P < 0.05），并且叶酸和核黄素之间存在影响NBUD水平的相互作用（P = 0.042）。这项初步研究表明，MTHFR C677T多态性和核黄素影响基因组不稳定性；然而，与叶酸相比，其影响相对较小。
We tested the hypothesis that methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism, folic acid deficiency and riboflavin deficiency, independently or interactively, are important determinants of genomic stability, cell death, cell proliferation and homocysteine (Hcy) concentration in 9-d human lymphocyte cultures. Lymphocytes of seven wild-type (CC) and seven mutant (TT) homozygotes were cultured under the four possible combinations of deficiency and sufficiency of riboflavin (0 and 500 nmol/L) and folic acid (20 and 100 nmol/L) at a constant L-methionine concentration of 50 mumol/L. Viable cell growth was 25% greater in TT than in CC cells (P < 0.05) and 32% greater at 100 nmol/L folic acid than at 20 nmol/L folic acid (P = 0.002). The comprehensive cytokinesis-block micronucleus assay was used to measure micronuclei (MNi; a marker for chromosome breakage and loss), nucleoplasmic bridges (NPB; a marker of chromosome rearrangement) and nuclear buds (NBUD, a marker of gene amplification). The MNi levels were 21% higher in TT cells than in CC cells (P < 0.05) and 42% lower in the high folic acid medium than in the low folic acid medium (P < 0.0001). The NBUD levels were 27% lower in TT cells than in CC cells (P < 0.05) and 45% lower in the high folic acid medium than in the low folic acid medium (P < 0.0001). High riboflavin concentration (500 nmol/L) increased NBUD levels by 25% (compared with 0 nmol/L riboflavin) in folate-deficient conditions (20 nmol/L folic acid medium; P < 0.05), and there was an interaction between folic acid and riboflavin that affected NBUD levels (P = 0.042). This preliminary investigation suggests that MTHFR C677T polymorphism and riboflavin affect genome instability; however, the effect is relatively small compared with that of folic acid.