甲醛与TMBIM家族相关基因交互作用影响早期胚胎发育的分子机制研究

TMBIM family is a group of anti-apoptosis factors emerged in recent years, and a variety of diseases are closely related to this family. our previous study showed that in zebrafish embryos exposed to formaldehyde, expression levels of gene tmbim1, tmbim3 and tmbim4 are upregulated. The development of zebrafish embryos are unaffected by knockdown of gene tmbim4. However, exposing tmbim4 knock-down embryos with low dose of formaldehyde, cell apoptosis are observed in these embryos and most of them are died at 2 days post fertilization. These results suggest that interactions of formaldehyde and gene tmbim4 affect early embryonic development. In this study, by using knockdown and knockout technology, combined with acute exposure experiments of formaldehyde, we try to find other members of TMBIM family affecting early embryonic development by interacting with formaldehyde. We hope this study could confirm genes in TMBIM family that are susceptible to formaldehyde and closely related to early embryonic development, and provide reliable basis for early-warning of people at high risk of spontaneous abortion and birth defect, but also provide new insights into investigating biomarkers of formaldehyde exposure inducing abnormal embryonic development.

TMBIM家族是近年来新发现的一组抗凋亡因子，与人类多种疾病密切相关。我们在前期研究中发现，甲醛暴露斑马鱼胚胎，能诱导tmbim1，tmbim3和tmbim4基因的上调表达。在斑马鱼胚胎中敲降tmbim4基因，胚胎发育不受影响。然而，以低浓度甲醛暴露tmbim4基因敲降的斑马鱼胚胎，胚胎在受精后第2天出现凋亡并死亡。说明甲醛与tmbim4基因共同作用影响早期胚胎发育。在本研究中，我们拟利用基因敲降和基因敲除技术，结合甲醛暴露急性毒理实验，观察敲降和敲除TMBIM家族成员的斑马鱼胚胎对甲醛暴露的敏感度，进一步筛查其它与甲醛交互作用影响早期胚胎发育的TMBIM家族成员，并进而深入探索其影响的分子机制。通过本研究，既有助于确定TMBIM家族中与早期胚胎发育密切相关的甲醛暴露易感基因，为自然流产和出生缺陷高危人群预警提供可靠依据，也为寻找甲醛暴露致胚胎发育异常的生物标记物提供新的思路。

三氯卡班（TCC）是一种亲脂性的抗菌剂，常用于家用和个人护理产品。最新的一项研究显示，TCC暴露增加胎儿畸形风险。TCC是否具有胚胎毒性，其毒性分子机制是什么，TCC暴露对哪些个体可能更敏感，目前还不清楚。本项目利用斑马鱼作为毒理学和发育生物学研究的理想模型，评估了TCC的胚胎毒性，并解析分子机制。研究发现斑马鱼胚胎暴露于环境相关浓度下的TCC可引起氧化应激随后通过Toll样受体信号传导途径释放促炎介质引起免疫应答相关基因表达的改变，诱导免疫毒性。环境相关浓度的TCC也通过诱导斑马鱼内质网（ER）应激和未折叠蛋白反应（UPR）影响胚胎的发育。TCC暴露斑马鱼胚胎诱导tmbim4上调表达。高浓度TCC暴露可以使tmbim4-/-的斑马鱼胚胎在84hpf时死亡。而tmbim4-/-胚胎过表达tmbim4 mRNA可拯救暴露于TCC中的tmbim4-/-胚胎，使其死亡率降低。进一步研究显示，TCC暴露导致tmbim4-/-胚胎自噬降解异常，导致自噬体过度积累，从而导致细胞凋亡增加，进一步引发其死亡。说明TCC与tmbim4-/-交互作用影响斑马鱼胚胎的早期发育。该研究为评估TCC暴露是否会对人胚胎发育产生风险，以及哪些人群为对三氯卡班暴露的易感人群提供了依据。