人类胚胎干细胞治疗心梗的免疫耐受策略及其机制研究

Myocardial infarction is a major healthcare problem in China. Studies have shown that myocardial is non-renewable and there is no effective treatment, therefore the mortality rate of heart failure after myocardial infarction remains in high level during recent years. Human Embryonic Stem Cells (hESCs) hold great promise in the field of regenerative medicine especially for myocardial infarction, but the key bottleneck is the immune rejection of hESC-derived allografts by the recipient. However, all of the current immunosuppressive strategies will inevitably increase the cancer risk of hESCs and their derivatives. We have established an immune tolerated hESCs cell line CPTK Hues3 hESCs previously. This cell line is capable to induce immune tolerance and reduce cancer risk simultaneously. We hypothesize that this cell line could repair damaged myocardium with a safety checkpoint, and can induce immune tolerance. This study will establish a CPTK H7 hESCs cell line. The functionality, safety, immune tolerance efficiency and the related mechanism of CPTK H7 hESCs derived cardiomyocytes will be evaluated using the immune system humanized rat myocardial infarction models. This study will provide reliable and more clinically relevant data of hESCs derived cardiomyocytes for myocardial infarction, which will improve the feasibility of hESCs-based cell treatment on myocardial infarction.

心肌梗死是我国医疗卫生面临的重大问题。由于心肌不可再生，心梗缺乏有效治疗方案，心梗引发心衰导致的死亡率一直居高不下。利用来源于hESCs的心肌细胞修复心梗是再生医学中的一个重要发展方向，但异体免疫排斥是其中最关键的瓶颈。目前临床上所采取的抑制移植排斥手段均会增加癌变及感染风险。项目申报人前期建立了一株同时表达CTLA4-Ig、PD-L1和TK的Hues3 hESCs，其分化细胞耐受异体免疫排斥、同时具有极小的癌变风险。申报人推测该细胞具有治疗心梗的作用和较高的安全性，并且能诱导免疫耐受。本项目拟通过建立CPTK H7 hESCs, 诱导其分化成为心肌细胞，在免疫系统人源化大鼠心梗模型中考察其治疗心梗的有效性和安全性、验证其诱导免疫耐受的作用及机制。该研究将会提供更可靠、更贴近临床的hESCs衍生心肌细胞治疗心梗临床前数据和诱导免疫耐受策略，促进基于hESCs的细胞治疗心梗的发展。

利用来源于hESCs的心肌细胞替换心梗后受损的心脏组织是过去十多年间再生医学研究中的热点之一。目前已有方法诱导hESCs分化得到高纯度的成熟的心肌细胞，hESCs应用于心脏修复治疗具有可行性和广阔的发展前景。hESCs能解决临床治疗中的细胞来源问题，但免疫排斥一直是影响hESCs应用于临床的最关键瓶颈之一。本项目通过构建一株同时表达CTLA4-Ig、PD-L1和HSV-TK的H7 hESCs，体外分化得到CPTK心肌细胞，验证其治疗心梗的有效性，并且研究其体内诱导免疫耐受的具体机制。通过本项目研究，我们将会得到更可靠、更贴近临床的hESCs治疗心梗的有效性、安全性和免疫耐受策略及其具体机制的临床前数据，能有效促进基于hESCs的再生医学治疗心梗的发展。本项目构建了同时表达CTLA4-Ig、PD-L1和HSV-TK的H7 hESCs和表达SOD-1的hESCs，这两株细胞均能分化成心肌细胞。另外构建了更健康的严重免疫缺陷大鼠NRG，此动物模型能广泛应用于免疫性、肿瘤学和再生医学研究，是一种具有广阔应用前景的动物模型。