全反式维甲酸调控K562细胞红系分化的表观遗传机制  

All-trans Retinoic Acid Regulates Erythroid Differentiation of K562 Cells via Epigenetic Mechanisms

作　　者：刘春亚 贾炳豪 唐琴 孙元田[1] 任立成 LIU Chun-Ya;JIA Bing-Hao;TANG Qin;SUN Yuan-Tian;REN Li-Cheng(Key Laboratory of Tropical Translational Medicine of Ministry of Education,Department of Biology,School of Basic Medicine and Life Sciences,Hainan Medical University,Haikou 571199,China)

机构地区：[1]海南医科大学,基础医学与生命科学学院,热带转化医学教育部重点实验室,生物学教研室,海口571199

出　　处：《中国生物化学与分子生物学报》2024年第10期1441-1452,共12页Chinese Journal of Biochemistry and Molecular Biology

基　　金：海南省科技专项(No.ZDYF2023SHFZ112);国家自然科学基金项目(No.31660318);校级研究生创新科研课题(No.HYYS2022B02)资助。

摘　　要：全反式维甲酸(ATRA)是早幼粒细胞分化的有效诱导剂,其对红系分化过程的作用尚不完全清楚。为研究ATRA在红系分化进程中的作用及其表观遗传调控机制,本文以诱导白血病细胞K562向红系分化为模型,对ATRA干扰红系分化过程的调控机制进行研究。首先利用血红素(he-min)诱导K562细胞向红系分化;流式细胞术结果显示,ATRA影响细胞向红系分化过程中的谱系变化,阻滞细胞分化进程;ATRA处理分化中的细胞后,红系分化相关基因表达水平降低;而通过3C、FAIRE和ChIP技术对其中的表观遗传机制进行探究发现,ATRA处理细胞后,β-珠蛋白家族基因座位内的染色质可及性降低,LCR与其靶基因启动子之间的相互作用频率降低;而基因座位染色质可及性降低导致了红系相关转录因子GATA1、LDB1、LMO2和TAL1在LCR及珠蛋白家族基因座位的启动子区的富集频率降低。上述结果表明,ATRA处理分化中的细胞导致红系分化相关基因的染色质可及性降低,更加封闭的染色质结构阻碍了LCR招募转录因子与基因启动子区的结合,进而抑制β-珠蛋白家族基因表达,这种动态的变化过程阐明了ATRA调控红系分化的表观遗传机制。All-trans retinoic acid(ATRA)is able to induce promyelocytic differentiation effectively.However,its role in the process of erythroid differentiation remains unclear.To investigate the role of ATRA in the process of erythroid differentiation and its epigenetic regulatory mechanism,we established an induced leukemia cell K562 model in this study.Firstly,hemin was used to induce the differentiation of K562 cells into erythroid cells.The results of flow cytometry showed that ATRA affected the lineage changes of cells during erythroid differentiation and blocked the process of cell differentiation.After ATRA treatment of differentiating cells,the expression level of erythroid differentiation-related genes decreased.Through chromatin conformational capture(3C),formaldehyde-assisted separation of regulatory elements(FAIRE),chromatin immunoprecipitation(ChIP)techniques,the epigenetic mechanism was explored and it was found that after ATRA treatment of cells,the chromatin accessibility within the β-globin family gene locus decreased,and the frequency of interaction between the locus control region(LCR)and its target gene promoter decreased.The decrease in the chromatin accessibility of the gene locus led to a decrease in the enrichment frequency of erythroid-related transcription factors GATA binding protein 1(GATA1),LIM domain binding 1(LDB1),LIM domain only 2(LMO2),and BHLH transcription factor 1(TAL1)at the promoter regions of the LCR and the gene locus of the globin family.The above results indicate that the ATRA treatment of differentiating cells leads to a decrease in the chromatin accessibility of erythroid differentiation-related genes,and a more closed chromatin structure hinders the binding of LCR-recruiting transcription factors to the promoter regions of genes,thereby further repressing the expression of β-globin family genes.This dynamic process elucidates the epigenetic mechanism of ATRA in regulating erythroid differentiation.

关 键 词：全反式维甲酸 红系分化 染色质构象捕获 染色质免疫沉淀 基因表达调控 

分 类 号：Q2[生物学—细胞生物学] Q3