RETROVIRAL VECTOR-MEDIATED LIVER GENE THERAPY FOR MPS I

摘要 粘多糖沉积症I型（MPS I）是一种由α-利杜糖醛酸酶缺陷引起的溶酶体贮积病 （IDUA）活性，导致糖胺聚糖类肝素的蓄积 和硫酸皮肤素。严重的形式，被称为赫尔勒综合征，导致骨和关节 畸形，肺和心脏疾病，听力和视力缺陷，智力迟钝， 5岁左右死亡，如果不治疗。造血干细胞移植可以减少一些 表现，但有15%的死亡率，成本130，000美元，需要一个兼容的捐赠者。 酶替代疗法也可以减轻一些症状，但每年的费用超过50万美元 对于成年人，需要每周输注一次，并不是所有患者都可以使用。制定一项 有效和安全的MPS I基因治疗可能会对患者的生活产生巨大的积极影响。 病人和照顾他们的家人。在上一个融资期，我们证明， 新生儿静脉注射γ逆转录病毒载体（g-RV）， 表达犬IDUA的重复序列（LTR）在小鼠和犬中均具有真正显著的效果， MPS I，所有主要临床表现消除或减轻。这至少部分是由于 分泌甘露糖6-磷酸（M6 P）修饰的IDUA的肝细胞的有效转导 进入血液，扩散到其他器官，并通过M6 P受体吸收。还有 血细胞的一些转导和大脑中未定义的细胞类型，这可能有助于 对治疗反应的影响。虽然用这种方法在小鼠或狗身上没有产生肿瘤， LTR-完整载体的插入诱变的风险是一个问题。另一个问题是 将该载体给予成年MPS I小鼠或新生MPS I猫导致有效的免疫抑制。 细胞毒性T淋巴细胞（CTL）反应，破坏转导的细胞。这次重建的目的 应用是：1）通过开发一种自失活的 在3' LTR的增强子中具有缺失的g-RV; 2）试图通过以下方式预防免疫应答： 避免在抗原呈递细胞中表达;和3）分析效力的持续时间， 在长寿大型动物模型（犬）中评价毒性。如果成功，这项研究可能会加速 为新生儿患者开发一种简单有效的治疗方法， MPS I的毁灭性临床表现

Abstract Mucopolysaccharidosis I (MPS I) is a lysosomal storage disease caused by deficient a-Liduronidase (IDUA) activity, which results in the accumulation of the glycosaminoglycans heparan and dermatan sulfate. The severe form, known as Hurler syndrome, causes bone and joint abnormalities, pulmonary and cardiac disease, hearing and visual deficiencies, mental retardation, and death around age 5 if untreated. Hematopoietic stem cell transplantation can reduce some manifestations, but has a 15% mortality rate, costs $130,000, and requires a compatible donor. Enzyme replacement therapy can also reduce some symptoms, but costs over $500,000 per year for an adult, requires a weekly infusion, and is not available to all patients. The development of an effective and safe gene therapy for MPS I could have a dramatic positive impact on the lives of patients and the families that care for them. In the previous funding period, we demonstrated that neonatal intravenous injection of a gamma retroviral vector (g-RV) with an intact long-terminal repeat (LTR) expressing canine IDUA had a truly remarkable effect in both mice and dogs with MPS I, with elimination or reduction in all major clinical manifestations. This was due at least in part to efficient transduction of liver cells, which secreted mannose 6-phosphate (M6P)-modified IDUA into blood, which diffused to other organs and was taken up via the M6P receptor. There was also some transduction of blood cells and an undefined cell type in brain, which may have contributed to the therapeutic response. Although no tumors developed in mice or dogs with this approach, the risk of insertional mutagenesis with an LTR-intact vector is a concern. Another problem is that administration of this vector to adult MPS I mice or newborn MPS I cats resulted in a potent cytotoxic T lymphocyte (CTL) response that destroyed transduced cells. The aims of this renewal application are to: 1) reduce the risk of insertional mutagenesis by developing a self-inactivating g-RV with a deletion in the enhancer of the 3' LTR; 2) attempt to prevent an immune response by avoiding expression in antigen-presenting cells; and 3) analyze the duration of efficacy and evaluate for toxicity in a long-lived large animal model (dog). If successful, this study may hasten the development of a simple and effective treatment for newborn patients that will reduce or prevent the devastating clinical manifestations of MPS I.