Second Generation Approaches to Foamy Virus (FV) Vector SCID-X1 Gene Therapy

X连锁严重联合免疫缺陷(SCID-XL)如果留下来，在生命的第一年都是致命的 未经治疗。造血干细胞(HSC)基因治疗为许多患者提供了最佳治疗选择 他们没有人类白细胞抗原匹配的捐献者。在SCID-XL的临床研究中，伽马逆转录病毒载体前病毒 包括LM02在内的附近原癌基因调控失调，导致克隆性扩张，在某些情况下是直白的 白血病。因此，需要不太可能反式激活原癌基因的更安全的载体系统来 SC1D-X1基因治疗。与用于SCID的伽马逆转录病毒载体相比，FV载体可能是一种更安全的替代方案。 XL临床试验。它们在原癌基因附近的整合方面具有良好的整合特征 与伽玛逆转录病毒和慢病毒载体相比，反式激活附近基因的倾向降低。 我们的长期目标是开发更安全、更有效的FV载体用于HSC基因治疗，并更好地 了解使用这些载体的相对风险。此外，我们希望更好地了解主机 影响FV的限制机制。如果可以识别并消除主机限制机制 用来产生FV载体的细胞，FV载体的效价可能会提高。这将降低 未来的临床试验，可能导致FV载体在临床上的更多使用。我们在这方面的目标 应用是使用一种评估遗传毒性的新方法来建立FV载体的相对安全性， 开发更安全的绝缘FV载体，提高FV载体的生产效率。我们将聘用 一种创新的穿梭载体方法，不依赖于基于PCR的指数扩增来更好地 了解FV载体潜在的遗传毒性。我们的建议与其他计划高度结合 项目。我们将合作在小鼠身上测试我们的新型绝缘FV SCID-XL载体(项目1)和 DOG(项目2)SCID-XL模型使用这种新的穿梭向量方法来生成非常显著的预 临床数据。我们的中心假设是，FV媒介的安全和生产效率可以提高。 这项拟议的研究具有重要意义，因为它有望导致FV载体在临床上的使用 威胁生命的疾病包括SCID-XL。 相关性： 拟议的项目与公共健康直接相关，因为正在开发改进的方法来评估 载体的遗传毒性，以及开发更安全和更有效的基因治疗载体有望导致 成功治疗SCID-XL等血液病。因此，拟议的研究是直接的 与美国国立卫生研究院开发创新研究战略并将其应用于改善人类健康的使命有关 健康。

X-linked severe combined immunodeficiency (SCID-Xl) is uniformly fatal in the first years of life if left untreated. Hematopoietic stem cell (HSC) gene therapy offers the best therapeutic option for many patients who do not have HLA-matched donors. In SCID-Xl clinical studies gammaretroviral vector proviruses have dysregulated nearby proto-oncogenes including LM02, leading to clonal expansion and in some cases frank leukemia. Thus, safer vector systems that are less likely to transactivate proto-oncogenes are needed for SC1D-X1 gene therapy. FV vectors may be a safer alternative to the gammaretroviral vectors used for SCID- Xl clinical trials. They have a favorable integration profile with respect to integration near proto-oncogenes and a reduced propensity to transactivate nearby genes relative to gammaretroviral and lentiviral vectors. Our long term goal is to develop safer and more effective FV vectors for HSC gene therapy, and to better understand the relative risks of using these vectors. Additionally, we would like to better understand host restriction mechanisms that impact FVs. If host restriction mechanisms can be identified and eliminated from the cells used to produce FV vectors, FV vector titers may be improved. This would reduce the costs of future clinical trials, potentially leading to increased use of FV vectors in the clinic. Our objectives in this application are to establish the relative safety of FV vectors using a novel approach to assess genotoxicity, to develop safer insulated FV vectors, and to improve the efficiency of FV vector production. We will employ an innovative shuttle vector approach that does not rely on PCR-based exponential amplification to better understand potential FV vector genotoxicity. Our proposal is highly integrated with the other program Projects. We will collaborate to test our novel insulated FV SCID-Xl vectors in the mouse (Project 1) and dog (Project 2) SCID-Xl models using this novel shuttle vector approach to generate highly significant pre- clinical data. Our central hypothesis is that FV vector safety and efficiency of production can be improved. The proposed research is significant because it is expected to lead to the use of FV vectors in the clinic for life-threatening diseases including SCID-Xl. RELEVANCE: The proposed project is directly related to public health because developing improved methods to assess vector genotoxicity, and developing safer and more effective gene therapy vectors is expected to lead to successful treatment of SCID-Xl and other hematopoietic diseases. The proposed research is thus directly related to the NIH's mission to develop innovative research strategies and apply them to improve human health.