Navakauskienė Rūta, Borutinskaitė Veronika V, Treigytė Gražina, Savickienė Jūratė, Matuzevičius Dalius, Navakauskas Dalius, Magnusson Karl-Eric
Department of Molecular Cell Biology, Institute of Biochemistry, Vilnius University, LT-08662 Vilnius, Lithuania.
BMC Cell Biol. 2014 Jan 20;15:4. doi: 10.1186/1471-2121-15-4.
Epigenetic regulation is known to affect gene expression, and recent research shows that aberrant DNA methylation patterning and histone modifications may play a role in leukemogenesis. In order to highlight the co-operation of epigenetic mechanisms acting during the latter process it is important to clarify their potential as biomarkers of granulocytic differentiation.
In this study we investigated epigenetic alterations in human hematopoietic cells at a distinct differentiation stages: primary hematopoietic CD34+ cells, KG1 myeloid leukemic cells, whose development is stopped at early stage of differentiation, and mature neutrophils. We focused on the epigenetic status of cell cycle regulating (p15, p16) and differentiation related (E-cadherin and RARβ) genes. We found that the methylation level in promoter regions of some of these genes was considerably higher in KG1 cells and lower in CD34+ cells and human neutrophils. As examined and evaluated by computer-assisted methods, histone H3 and H4 modifications, i.e. H3K4Me3, H3K9Ac, H3K9Ac/S10Ph and H4 hyperAc, were similar in CD34+ cells and human mature neutrophils. By contrast, in the KG1 cells, histone H3 and H4 modifications were quite high and increased after induction of granulocytic differentiation with the HDAC inhibitor phenyl butyrate.
We found the methylation status of the examined gene promoters and histone modifications to be characteristically associated with the hematopoietic cell progenitor state, induced to differentiate myeloid KG1 cells and normal blood neutrophils. This could be achieved through epigenetic regulation of E-cadherin, p15, p16 and RARβ genes expression caused by DNA methylation/demethylation, core and linker histones distribution in stem hematopoietic cells, induced to differentiation KG1 cells and mature human neutrophils, as well as the histone modifications H3K4Me3, H3K9Ac, H3K9Ac/S10Ph and H4 hyperAc in relation to hematopoietic cell differentiation to granulocyte. These findings also suggest them as potentially important biomarkers of hematopoietic cell granulocytic differentiation and could be valuable for leukemia induced differentiation therapy.
已知表观遗传调控会影响基因表达，近期研究表明，异常的DNA甲基化模式和组蛋白修饰可能在白血病发生过程中发挥作用。为了突出在后者过程中起作用的表观遗传机制的协同作用，阐明它们作为粒细胞分化生物标志物的潜力很重要。
在本研究中，我们调查了处于不同分化阶段的人类造血细胞中的表观遗传改变：原发性造血CD34+细胞、KG1髓系白血病细胞（其发育在分化早期停止）和成熟中性粒细胞。我们关注细胞周期调节（p15、p16）和分化相关（E-钙黏蛋白和RARβ）基因的表观遗传状态。我们发现，其中一些基因启动子区域的甲基化水平在KG1细胞中相当高，而在CD34+细胞和人类中性粒细胞中较低。通过计算机辅助方法检测和评估，组蛋白H3和H4修饰，即H3K4Me3、H3K9Ac、H3K9Ac/S10Ph和H4高乙酰化，在CD34+细胞和人类成熟中性粒细胞中相似。相比之下，在KG1细胞中，组蛋白H3和H4修饰相当高，在用组蛋白去乙酰化酶抑制剂苯丁酸盐诱导粒细胞分化后增加。
我们发现所检测基因启动子的甲基化状态和组蛋白修饰与造血细胞祖细胞状态、诱导分化的髓系KG1细胞和正常血液中性粒细胞具有特征性关联。这可以通过DNA甲基化/去甲基化、造血干细胞中核心和连接组蛋白的分布、诱导分化的KG1细胞和成熟人类中性粒细胞中E-钙黏蛋白、p15、p16和RARβ基因表达的表观遗传调控，以及与造血细胞向粒细胞分化相关的组蛋白修饰H3K4Me3、H3K9Ac、H3K9Ac/S10Ph和H4高乙酰化来实现。这些发现还表明它们可能是造血细胞粒细胞分化的重要生物标志物，对白血病诱导分化治疗可能有价值。
