心脏特异性高表达的金属硫蛋白预防三氧化二砷心脏毒性的效应及机制研究

One main problem which limits the wide application of ATO(As2O3) to tumor patients (including APL) is severe cardiotoxicity. Currently, the exact mechanism by which ATO causes myocardial toxicity remains unclear, and no functional management is obtained to prevent and treat this toxicity . As a new apoptotic pathway, endoplasmic reticulum stress may plays an important role in this cardiac damage. Nowadays we can not get any information about ERS in the arsenite induced cardiotoxicity. Our Pre-experiment showed the ERS related apoptotic proteins' expression -CHOP and Cleaved Caspase-12. So ERS and its related proteins may play some functions in the ATO induced cardiac cell death. To find effective way to resolve the problem of arsenite cardiotoxicity is a hot focus these years. Our pre-experiment had showed the excellent protective role of MT from arsenite damage to the H9c2 cells. So one hypothesis of this study is: MT can alleviate or prevent the cardiac toxicity of ATO. Some study showed Bismuth compound could specificly induced MT expression in the heart, and did not influence the anti-tumor effect of chemotherapy. So another hypothesis of this study produced: Bismuth may also plays a protective function in the ATO-induced cardiotoxicity, and the specificly induction of MT in the heart may be the pathway. To prove these hypothesises,we will do studies by the ways as follows: Study 1: In vitro, to define whether arsenite induces cardiac cell death via ER stress and whehter MT can prevent ATO-induced cell death via inhibtion of Arsenic-induced ER stress. We will use CHOP siRNA, ERS inhibitor and CHOP overexpressing carrier to elucidate how about ERS and MT roles in the ATO-induced cardiac cell death.Our results we have got will show in this document. Study 2: In vivo, to confirm that MT overexpression can protect arsenic induced cardiac cell death via inhibition of arsenic-induced ER stress. We will use MT-TG, MT -KO and WT mice here. Study 3:In vivo, to define Bismuth-induced cardiac MT expression provide MT-TG-like cardiac protection from arsenite using NOD/SCID leukemia mice model. In our pre-experiment, we have see the increasing expression of CHOP, C-Caspase12 which are the markers of ERS in the process of ATO-induced cell death. Using the metallothinein overexpressing cardiac cell modal -H9c2MT7 which we have set up, and the mouse modal -MT-TG and MT-KO,by technology of immunohistochemistry and molecular biology, we can further calrify these two hypothesises.

三氧化二砷（ATO）的心脏毒性是限制其临床应用的主要因素。ATO心脏毒性的分子机理不清。本课题组预实验发现ATO诱导心肌细胞凋亡伴随着内质网应激(ERS）相关标记分子包括凋亡蛋白酶Caspase-12、Caspase-3的显著激活及CHOP蛋白的表达增加，提示ERS可能介导了ATO诱导的心肌细胞凋亡。同时本预实验发现心肌细胞特异性高表达金属硫蛋白（MT）能有效预防ATO诱导的心肌细胞凋亡，伴随ERS相关标记分子显著下调。据此本课题组提出如下科学假设：通过抑制ERS凋亡途径，MT能够减少ATO诱导的心肌细胞凋亡, 从而预防ATO心脏毒性的发生。为验证该假设，本课题组拟利用已建立的特异性高表达MT的心肌细胞模型H9c2MT及小鼠模型MT-TG,系统剖析MT预防ATO心脏毒性的效应及其分子、细胞机制，并探讨心脏特异性的MT表达诱导剂-铋剂等诱导心肌细胞高表达MT从而预防ATO心脏毒性的可行性。

三氧化二砷（ATO）的心脏毒性是限制其临床应用的主要因素。ATO心脏毒性的分子机理不清。本课题组预实验发现ATO诱导心肌细胞凋亡伴随着内质网应激(ERS）相关标记分子包括凋亡蛋白酶Caspase-12、Caspase-3的显著激活及CHOP蛋白的表达增加，提示ERS介导了ATO诱导的心肌细胞凋亡。同时本实验发现心肌细胞特异性高表达金属硫蛋白（MT）能有效预防ATO诱导的心肌细胞凋亡，伴随ERS相关标记分子显著下调。据此本课题组提出如下科学假设：通过抑制ERS凋亡途径，MT能够减少ATO诱导的心肌细胞凋亡, 从而预防ATO心脏毒性的发生。为验证该假设，本课题组计划利用已建立的特异性高表达MT的心肌细胞模型H9c2MT及小鼠模型MT-TG,系统剖析MT预防ATO心脏毒性的效应及其分子、细胞机制，并探讨心脏特异性的MT表达诱导剂-铋剂等诱导心肌细胞高表达MT从而预防ATO心脏毒性的可行性。目前的研究表明ATO诱导的心肌细胞凋亡有ERS相关蛋白分子的激活，其中MAPKs的通路激活最明显，而MT对心肌细胞的保护作用主要通过抑制MAPKs通路的激活而发挥保护作用。在进行此项研究过程中，MT心脏保护作用的文章不断涌现，故本课题组与相关研究中心合作，进一步探讨了MT心脏保护作用的机制，尤其是从锌诱导MT对肥胖导致的心脏损伤以及从表观遗传学角度进一步阐明了MT心脏保护作用的机制。参与发表SCI论文3篇，参与编写MT专著1章节。同时获本项目资助发表临床SCI论文1篇、核心期刊论文1篇。本课题关于MT的高表达是否影响亚砷酸抗白血病的疗效的相关研究正在进行中。陆续相关成果会以SCI文章形式发表。