β地中海贫血症基因修复治疗的研究

Thalassemia is the most prevalent genetic disease in the world and in China. Although blood transfusion and iron chelation can extend lifespan of the patients, there are thousands of people died of this devastating genetic disease each year. Gene therapy has been developed to treat this disease, but the existing gene therapy still pose hazards to the patients. Gene targeting is the most likely technique to improve the safety of gene therapy. By using homologous recombination, the technique can correct the genetic mutations and avoid the mutations and cancers caused by traditional gene therapy. Recently, zinc finger nuclease, TALEN, CRISPR-CAS9 system and homing endonuclease have been widely used in gene targeting. Even though these systems can generate highly homologous recombination, their off-target effects need to be examined before the technique can be clinically applied. To create a highly specific gene correction with low genotoxicity, we propose to combine the low genotoxicity of homing nuclease and highly specific gene targeting of TALEN，and construct a fusion endonuclease TALE-ISceI. We will apply the gene correction in hematopoietic stem cells procured from βthalassemia patients. This research will provide the knowledge and experimental system to develop treatment toβthalassemia and other genetic diseases.

地中海贫血症是中国及全球最高发、分布最广的遗传疾病。虽然输血及去铁治疗能延缓病人的寿命, 但每年仍有数万人死于此疾病。基因治疗法已被嘗试应用于根治此症，但已报道的治疗法仍存在很大的安全隐患。基因打靶技术是目前最可能提高基因治疗安全性的技术。它通过同源重组修复，修正突变基因，并避免传统基因治疗中造成的基因突变及癌症。锌指核酸酶、TALEN核酸酶、CRISPR-CAS9系统以及归巢内切酶已被广泛用于基因打靶技术。尽管这些系统能够诱导产生高效的同源重组修复，但其脱靶效应而导致的基因重组及突变毒性，在临床应用上仍需经过严谨的测试。为探索高效修复且低毒性的基因打靶技术，我们尝试综合利用归巢内切酶低基因毒性和TALEN高效打靶的优势，构建融合型内切酶TALE-ISceI。接着, 我们将用β-地中海贫血疾病患者造血干细胞为模型，对其突变基因进行修复。此项研究将为遗传疾病提供基因治疗的理论和实验依据。

地中海贫血症是中国及全球最高发、分布最广的遗传疾病。虽然输血及去铁治疗能延缓病人的寿命, 但每年仍有数万人死于此疾病。基因治疗法已被嘗试应用于根治此症，但已报道的治疗法仍存在很大的安全隐患。基因打靶技术是目前最可能提高基因治疗安全性的技术。它通过同源重组修复，修正突变基因，并避免传统基因治疗中造成的基因突变及癌症。锌指核酸酶、TALEN核酸酶、CRISPR-CAS9系统以及归巢内切酶已被广泛用于基因打靶技术。尽管这些系统能够诱导产生高效的同源重组修复，但其脱靶效应而导致的基因重组及突变毒性，在临床应用上仍需经过严谨的测试。为探索高效修复且低毒性的基因打靶技术，我们尝试综合利用归巢内切酶低基因毒性和TALEN高效打靶的优势，构建融合型内切酶TALE-ISceI。此项研究将为遗传疾病提供基因治疗的理论和实验依据。