Evi1基因在苯致造血毒性中的作用及机制研究

Benzene is a ubiquitous environmental and occupational pollutant. It is also the primary material which causes chronic occupational poisoning in China. In our previous study, benzene exposure induced decreased hematopoietic stem cell number, inhibition of differentiation and colony formation ability in mice. In addition, significant increase in the Evi1 level was also observed. The aim of this study was to investigate whether Evi1 gene plays a role in the benzene-induced hematotoxicity by regulating hematopoietic stem cells, causing hematopoietic cell number and function changes, and to explore the mechanism of action.. We intend to use mouse model to investigate whether Evi1 plays a role in benzene-induced hematopoietic toxicity by regulating hematopoietic stem cells ;use Evi1 low-expressing cell to study the downstream pathways which Evi1 participates in the cytotoxicity of benzene metabolites and reveal the molecular mechanism of Evi1 action; conduct an occupational epidemiological study to expolore the relationship between Evi1 expression and the hematopoietic toxicity of occupational benzene-exposed workers.. The results of this study will reveal the role and molecular mechanism of Evi1 in benzene-induced hematopoietic toxicity, which will provide an important scientific basis for the early effects indicators and primary prevention of hematopoietic toxicity induced by benzene.

苯是常见的环境污染物和职业危险因素，也是我国引起慢性职业中毒的首要物质。我们前期研究发现，苯暴露可引起小鼠骨髓造血干细胞数量减少、分化受阻、造血干/祖细胞集落形成能力受到抑制，骨髓细胞Evi1表达显著增加。本课题旨在研究Evi1基因是否通过调节造血干细胞引起造血细胞数量及功能改变，在苯致骨髓造血毒性中发挥作用，并探索其中的作用机制。. 本课题拟通过已建立的小鼠苯暴露造血毒性模型，研究Evi1是否通过调控造血干细胞在苯致造血毒性中发挥作用；建立Evi1低表达细胞，研究Evi1参与苯代谢产物细胞毒性的下游通路，揭示Evi1作用的分子机制；结合职业流行病学调查研究Evi1表达与职业苯暴露工人造血毒性的关系。. 研究结果将明确Evi1在苯造血毒性中的作用及分子机制，为发现苯致造血毒性中的早期效应指标及一级预防提供重要的科学依据。

本课题首先通过构建苯中毒小鼠模型，发现苯暴露在引起血液毒性的同时，导致小鼠骨髓细胞凋亡和增殖显著增加、Evi1蛋白水平异常增加，Evi1调控细胞凋亡和增殖的JNK通路等发生改变，表明Evi1可能参与苯致骨髓造血毒性。.随后，我们利用慢病毒转染K562细胞构建Evi1稳定低表达的细胞，研究Evi1低表达对苯代谢产物1,4-苯醌（1,4-BQ）致K562细胞毒性作用的影响。结果发现，Evi1可能通过激活PI3K/AKT通路加剧1,4-BQ暴露诱导的细胞增殖抑制和G0/G1阻滞，进而影响1,4-BQ对K562细胞的毒性。应用染色质免疫共沉淀测序技术ChIP-Seq，筛选在1,4-苯醌引起的细胞毒性过程中，Evi1参与调控的靶基因。结果表明Evi1可能通过下游靶基因FAM72B、FRG2B、USP14、EMB和TAS1R3等参与1,4-BQ的细胞毒性。最后，在健康人群和苯暴露人群外周血白细胞中检测Evi1的表达水平，探索其作为生物标志物的可能性。结果发现，未发生苯中毒的苯暴露工人外周血中白细胞Evi1水平显著增加，Evi1表达水平可作为潜在的苯血液毒性早期损伤效应标志物。研究成果可为进一步阐明苯造血毒性机制、发现苯暴露人群血液毒性的早期损伤标志物及干预提供科学基础。