Myeloablative conditioning and late complications in ARTEMIS-deficient SCID

项目摘要 非常多样化的抗原受体基因是由许多V、D和J编码片段组装而成的 通过淋巴特异性DNA重排、V(D)J重组。V(D)J缺陷重组受损 淋巴细胞发育，从而导致免疫缺陷。非同源末端连接(NHEJ) 在V(D)J重组过程中需要途径，因为它是主要的DNA双链之一 中断(DSB)修复路径。几乎所有NHEJ基因的突变都被发现与 人类原发免疫缺陷综合征。Artemis是NHEJ基因突变最频繁的基因， 最初在辐射敏感型重症联合免疫缺陷综合征中发现RS-SCID。NHEJ- 缺陷患者可以接受造血细胞移植，以重建T和B细胞功能。 然而，由于NHEJ对所有细胞类型的DSB修复都是关键的，因此涉及辐射的预适应方案 造成过度的组织损伤，并可能导致死亡。青蒿素缺乏症患者已成功 移植T细胞和B细胞，并使用烷化剂进行清髓处理。然而，这些患者 表现出晚期并发症，包括生长障碍、内分泌缺陷和牙齿异常。目标 是为了阐明与清髓剂相关的毒性的潜在机制 使用我们先前开发和表征的NHEJ-小鼠模型用烷化剂进行条件化 缺乏SCID和确定替代调理方案的疗效。发病较晚的可能性 相关的肿瘤发生也将被检查。总而言之，这些研究将提供对 NHEJ缺陷的初级免疫缺陷的晚期毒性的原因，并可能导致 开发更有效的治疗方法。

PROJECT ABSTRACT The vastly diverse antigen receptor genes are assembled from numerous V, D and J coding segments via the lymphoid specific DNA rearrangement, V(D)J recombination. Defective V(D)J recombination impairs lymphocyte development and thus, results in immunodeficiency. The non-homologous end joining (NHEJ) pathway is required during V(D)J recombination by virtue of its role as one of the major DNA double strand break (DSB) repair pathways. Mutations in nearly all of the NHEJ genes have been found in association with human primary immunodeficiency syndromes. ARTEMIS is the most frequently mutated NHEJ gene and was initially discovered in the radiation sensitive severe combined immunodeficiency syndrome, RS-SCID. NHEJ- deficient patients can undergo hematopoietic cell transplantation to reconstitute T and B cell functions. However, because NHEJ is critical for DSB repair in all cell types, conditioning regimens involving radiation cause excessive tissue damage and can lead to mortality. ARTEMIS-deficient patients have been successfully engrafted with T and B cells with myeloablative conditioning using alkylating agents. However, these patients exhibit late complications including growth failure, endocrine deficiencies and dental abnormalities. The goals of this proposal are to elucidate the mechanisms underlying the toxicities associated with myeloablative conditioning with alkylating agents using our previously developed and characterized mouse models of NHEJ- deficient SCID and to determine the efficacy of alternative conditioning regimens. The potential for late onset tumorigenesis associated will also be examined. Together, these studies will provide mechanistic insight into the causes of late toxicities in NHEJ-deficient primary immunodeficiencies and potentially lead to the development of more effective therapies.