CPS1缺陷型尿素循环障碍高氨血症体外疾病模型的建立及其基因修复的研究

Urea cycle disorders Hyperammonemia is a deficiency in the enzyme involved in the urea cycle in the human body, resulting in ammonia, a metabolite of the protein, which cannot be converted into urea but remains in the body, resulting in increased blood ammonia, which results in irreversible damage mainly to the nervous system. In various subtypes, CPS1 (carbamyl phosphate synthetase) deficiency affects the first-step response of the urea cycle, leading to death in children within a few weeks after birth, and the mortality rate is extremely high, whereas the liver transplantation method corresponds to very few donors, there are few types of urea-degrading drugs and they are expensive, so there is no good treatment at present. There is an urgent need for a human cell model that responds to disease. Our research group has established a CPS1-defective induced pluripotent stem cell line using cell reprogramming technology, and also an efficient induction program for pluripotent stem cells to hepatic progenitor cells and hepatic terminal cells. This study intends to induce differentiation of the disease iPS lineage into hepatic progenitor cells and 3D mini-livers, reproduce the occurrence of the disease phenotype, and observe whether the disease phenotype can be corrected by the CAS9 technique. Through this study, an model of CPS1-defective urea cycle disease in vitro can be established and the effect of gene repair can be evaluated. This provides a powerful model tool for studying the pathogenesis of UCD disease and drug screening, and helps to promote the development of new therapeutic methods.

尿素循环障碍高血氨症即人体内参与尿素循环的酶发生了缺陷，导致蛋白质的代谢产物氨无法转变成尿素而滞留体内，导致血氨增高，从而造成以神经系统为主的不可逆损伤。在各种亚型中，CPS1（氨甲酰磷酸合成酶）缺陷型影响尿素循环的首步反应，导致患儿在出生后几周内死亡，死亡率极高，而肝移植法配型对应的供体极少，尿素替代降解药物的种类少且价格昂贵，因此目前还没有好的治疗手段，急迫需要对应该疾病的人类细胞模型。课题组前期利用细胞重编程技术建立了CPS1缺陷的诱导多能干细胞系，并掌握了多能干细胞向肝祖细胞、肝终末细胞高效的诱导方案。本研究拟诱导该疾病iPS系向肝脏祖细胞及3D迷你肝脏进行分化，重现疾病表型的发生并观察能否通过CAS9技术将疾病表型进行纠正。通过本研究可以建立CPS1缺陷型尿素循环症的体外模型并评价基因修复的作用，为该疾病发病机制的研究和药物筛选提供有力的模型工具，并有助于推动治疗新方法的研发。

尿素循环障碍高血氨症即人体内参与尿素循环的酶发生了缺陷，导致蛋白质的代谢产物氨无法转变成尿素而滞留体内，导致血氨增高，从而造成以神经系统为主的不可逆损伤。在各种亚型中，CPS1（氨甲酰磷酸合成酶）缺陷型影响尿素循环的首步反应，导致患儿在出生后几周内死亡，死亡率极高，而肝移植法配型对应的供体极少，尿素替代降解药物的种类少且价格昂贵，因此目前还没有好的治疗手段，急迫需要对应该疾病的人类细胞模型。课题组利用胚胎干细胞建系技术建立了CPS1缺陷的胚胎干细胞系，并掌握了多能干细胞向迷你肝组织的诱导方案，诱导该疾病ESCs向3D迷你肝脏进行分化，结合cas9的基因修复技术，体外重现疾病表型的发生和被挽救。本研究建立CPS1缺陷型尿素循环症的体外模型并评价基因修复的作用，为该疾病发病机制的研究和药物筛选提供有力的模型工具，并有助于推动治疗新方法的研发。