丁酸钠对K562细胞系γ珠蛋白基因表达的诱导作用及机制

Sodium butyrate-induced expression of γ globin gene and its mechanisms

目的:研究丁酸钠对K562细胞系γ珠蛋白基因表达和胎儿血红蛋白合成的诱导作用及机制。方法:以丁酸钠(0.5 mmoL/L)诱导72h的K562细胞为实验组,设K562亲本细胞和SB203580(10μmol/L)处理1h后用丁酸钠(0.5 mmoL/L)诱导72h的K562细胞为阴性对照组,设羟基脲(100μmol/L)诱导72h的K562细胞为阳性对照。分别提取细胞总RNA和总蛋白。采用RT-PCR、Western blotting和联苯胺染色方法检测γ珠蛋白基因、胎儿血红蛋白和p38表达及p38磷酸化水平。结果:与K562亲本细胞和SB203580处理后丁酸钠诱导的K562细胞相比,丁酸钠诱导的K562细胞中G-γ珠蛋白、A-γ珠蛋白和胎儿血红蛋白的表达均明显上调(P<0.05),p38 mRNA和蛋白水平表达均无明显变化(P>0.05),但p38蛋白磷酸化水平显著增加(P<0.05)。K562亲本细胞、SB203580处理后丁酸钠诱导的K562细胞和丁酸钠诱导的K562细胞中联苯胺阳性细胞百分率分别为(3.2±0.4)%、(12.7±0.2)%和(36.3±0.8)%(P<0.05)。结论:丁酸钠可以诱导K562细胞高表达γ珠蛋白基因、合成胎儿血红蛋白,p38MAPKs的激活在丁酸钠诱导K562细胞高表达γ珠蛋白基因中发挥重要作用。

Aim ： To investigate the role of sodium butyrate in γ globin gene expression and fetal hemoglobin induction and its mechanisms. Methods：The K562 cells induced with 0.5 mmol/L sodium butyrate for 72 h were chosen as the experimental group, while the K562 parental cells and the K562 cells induced with 0.5 mmol/L sodium butyrate for 72 h followed by treatment with SB203580（ 10 μmol/L） for 1 h were set up as the negative control groups. Meanwhile, the K562 cells induced with 100 μmol/L hydroxyurea for 72 h were used as the positive control group. The total RNA and protein of different cell models were extracted, respectively. Then, the expressions of γ globin gene, fetal hemoglobin, p38, and the level of p38 phosphorylation were analyzed by RT-PCR, Western blotting, and benzidine staining. Results： The results of RT-PCR and Western blotting showed that there were no evident changes in the mRNA and protein levels of p38 expression for various groups（P 〉 0.05） , but compared with the negative control groups, the expression of G-γ globin gene, A-γ globin gene, and fetal hemoglobin, as well as the level of p38 phosphorylation in the experimental group were significantly increased （ P 〈 0.05 ）. The results of benzidine staining displayed that the mean percentages of positive cells stained by benzidine in K562 cells, K562 cells induced with sodium butyrate followed by treatment with SB203580, and K562 cells induced with sodium butyrate alone were （3.2± 0.4） %, （ 12.7±0.2 ） %, （ 36.3 ±0.8 ） %, respectively, and there were significant differences among the 3 groups （ P 〈0.05 ）. Conclusion ： Sodium butyrate can activate γ globin gene expression and fetal hemoglobin induction, and p38 may play an important role in sodium butyrate-induced expression of γ globin gene in human K562 cells.