Fetal Stem Cell Gene Therapy

说明(改编自应用程序) 越来越多的血液病可以在出生前诊断出来。在……里面 在某些情况下，早期治疗可能有利于胎儿的健康和存活。 无论是子宫内干细胞移植(IUT)还是胎儿基因治疗都可以治疗 血球蛋白病等疾病。此应用程序旨在确定 将基因导入胎儿造血干细胞的最佳方法 (HSCs)。胎儿的HSCs比他们的成年同龄人更具增殖性 因此，假设更容易被转导 基于小鼠白血病病毒或人类免疫缺陷的逆转录病毒载体 病毒。宫内节育器提供了另一种治疗多种血液病的方法 产生一种造血嵌合体的状态。然而，在没有任何 对供者造血干细胞的优势，嵌合体水平可以通过 宫内节育率较低。这将这种疗法的使用限制在极少数疾病上。我们的目标 是将宫内节育器的使用扩大到治疗地中海贫血等疾病 和镰状细胞性贫血，通过改造HSC使其具有增殖优势 而不是正常的造血干细胞。此应用程序将测试是否引入 促红细胞生成素受体(EPOR)进入HSCs将使这些改变的细胞 对促红细胞生成素(EPO)有反应。这将反过来导致改变 造血干细胞及其后代具有高于正常的增殖优势 祖先。截断形式的EPOR(TEpoR)也将进行测试。这些tEpoR， 在它们的细胞质负调控区有缺失 结构域，提供比EPOR更强的增殖信号。的影响 导入EPOR基因对HSCs增殖和分化的影响 他们的祖先后代将通过各种体外培养来确定 系统。假设EpoR或tEpoR异位表达 将赋予造血干细胞和早期祖细胞在 对EPO的反应对这些细胞的分化程序影响最小 细胞。检测HSC异位表达EPOR或tEpoR是否能使这些细胞 改良的造血干细胞比普通干细胞更具竞争力，将进行测试 在人类造血的小鼠模型中对照HSCs。的能力 不表达异位EPOR或仅表达EPOR的HSCs移植骨髓 细胞消融也将进行测试。这些活体实验将进一步 确定使HSC对EPO作出响应是否会对 长期重组和多血统的潜力 造血干细胞。拟议研究的积极结果将有助于制定 从造血论治血红蛋白病 异基因嵌合体。

DESCRIPTION (adapted from the application) A growing number of hematological diseases can be diagnosed before birth. In some cases, early treatment may benefit the health and survival of the fetus. Either in utero stem cell transplantation (IUT) or fetal gene therapy may treat diseases such as the hemaglobinopathies. This application aims to determine the best method for the introduction of genes into fetal hematopoietic stem cells (HSCs). Fetal HSCs are more proliferative than their adult counterparts and are, therefore, hypothesized to be more susceptible to transduction by retroviral vectors based on murine leukemia virus or human immunodeficiency virus. IUT offers another means of curing a number of hematological diseases by generating a state of hematopoietic chimerism. However, in the absence of any advantage for the donor HSCs, the levels of chimerism that can be achieved by IUT are low. This limits the use of this therapy to very few diseases. Our aim is to extend the use of IUT to the treatment of diseases, such as thalassemia and sickle cell anemia, by engineering HSCs to have a proliferative advantage over normal HSCs. This application will test if introduction of the erythropoietin receptor (EpoR) into HSCs will render these altered cells responsive to erythropoietin (EPO). This will in turn result in the altered HSCs and their progeny having a proliferative advantage over normal progenitors. Truncated forms of EpoR (tEpoR) will also be tested. These tEpoR, having deletions in the negative regulatory region of their cytoplasmic domains, deliver stronger proliferative signals than EpoR. The effects of introducing the EpoR genes on the proliferation and differentiation of HSCs and their progenitor progeny will be determined using various in vitro culture systems. It is hypothesized that ectopic expression of either EpoR or tEpoR will confer the ability of HSCs and early progenitors to proliferate in response to EPO with minimal effect on the differentiation program of these cells. To test if ectopic EpoR or tEpoR expression on HSCs can make these cells more competitive than their normal counterparts, modified HSCs will be tested against control HSCs in a mouse model of human hematopoiesis. The ability of HSCs expressing ectopic EpoR to engraft bone marrow after no or only minimal cytoablation will also be tested. These in vivo experiments will further determine if making HSCs responsive to EPO will have any detrimental effect on the long‑term reconstituting‑ and multilineage‑ potential of HSCs. A positive outcome from the proposed studies would aid in developing treatments for hemoglobinopathies based on generating hematopoietic allochimerism.