Persons Derek A, Hargrove Phillip W, Allay Esther R, Hanawa Hideki, Nienhuis Arthur W
Division of Experimental Hematology, Department of Hematology and Oncology, St Jude Children's Research Hospital, Memphis, TN 38105, USA.
Blood. 2003 Mar 15;101(6):2175-83. doi: 10.1182/blood-2002-07-2211. Epub 2002 Oct 31.
Increased fetal hemoglobin (HbF) levels diminish the clinical severity of beta-thalassemia and sickle cell anemia. A treatment strategy using autologous stem cell-targeted gene transfer of a gamma-globin gene may therefore have therapeutic potential. We evaluated oncoretroviral- and lentiviral-based gamma-globin vectors for expression in transduced erythroid cell lines. Compared with gamma-globin, oncoretroviral vectors containing either a beta-spectrin or beta-globin promoter and the alpha-globin HS40 element, a gamma-globin lentiviral vector utilizing the beta-globin promoter and elements from the beta-globin locus control region demonstrated a higher probability of expression. This lentiviral vector design was evaluated in lethally irradiated mice that received transplants of transduced bone marrow cells. Long-term, stable erythroid expression of human gamma-globin was observed with levels of vector-encoded gamma-globin mRNA ranging from 9% to 19% of total murine alpha-globin mRNA. The therapeutic efficacy of the vector was subsequently evaluated in a murine model of beta-thalassemia intermedia. The majority of mice that underwent transplantation expressed significant levels of chimeric m(alpha)(2)h(gamma)(2) molecules (termed HbF), the amount of which correlated with the degree of phenotypic improvement. A group of animals with a mean HbF level of 21% displayed a 2.5 g/dL (25 g/L) improvement in Hb concentration and normalization of erythrocyte morphology relative to control animals. gamma-Globin expression and phenotypic improvement was variably lower in other animals due to differences in vector copy number and chromosomal position effects. These data establish the potential of using a gamma-globin lentiviral vector for gene therapy of beta-thalassemia.
胎儿血红蛋白（HbF）水平升高可减轻β地中海贫血和镰状细胞贫血的临床严重程度。因此，一种使用自体干细胞靶向γ珠蛋白基因转移的治疗策略可能具有治疗潜力。我们评估了基于γ珠蛋白的逆转录病毒载体和慢病毒载体在转导的红系细胞系中的表达情况。与γ珠蛋白相比，含有β-血影蛋白或β-珠蛋白启动子以及α-珠蛋白HS40元件的逆转录病毒载体、利用β-珠蛋白启动子和来自β-珠蛋白基因座控制区元件的γ珠蛋白慢病毒载体表现出更高的表达可能性。在接受转导骨髓细胞移植的经致死性照射的小鼠中评估了这种慢病毒载体设计。观察到人类γ珠蛋白的长期稳定红系表达，载体编码的γ珠蛋白mRNA水平占小鼠总α珠蛋白mRNA的9%至19%。随后在中间型β地中海贫血小鼠模型中评估了该载体的治疗效果。大多数接受移植的小鼠表达了显著水平的嵌合m(α)(2)h(γ)(2)分子（称为HbF），其含量与表型改善程度相关。一组平均HbF水平为21%的动物相对于对照动物，血红蛋白浓度提高了2.5 g/dL（25 g/L），红细胞形态恢复正常。由于载体拷贝数和染色体位置效应的差异，其他动物中的γ珠蛋白表达和表型改善程度有所不同。这些数据证实了使用γ珠蛋白慢病毒载体进行β地中海贫血基因治疗的潜力。
