ADENO ASSOCIATED VIRUS GENE THERAPY FOR THE CNS IN MUCO

大多数影响中枢神经系统（CNS）的遗传性疾病会在整个大脑中产生代谢异常和病变。 体细胞基因转移有可能阻止或逆转许多遗传性疾病的疾病过程。然而，目前可用于将基因转移到中枢神经系统中的方法通常仅将外源基因递送到有限数量的细胞或特定结构。 影响CNS的一大类人类遗传疾病是溶酶体贮积症，其特征在于精神发育迟滞和其他进行性退行性异常。我们研究的长期目标是开发一种方法，将正常的溶酶体酶基因以一种可以纠正这组神经退行性疾病典型的播散性病变的方式递送到大脑中。 在这项研究中，我们将研究腺相关病毒（AAV）载体介导的治疗基因，β-葡萄糖醛酸酶（GUSB），在GUSB缺陷的粘多糖样变性（MPS）VII型（Sly病），一个代表性的神经退行性疾病的动物模型的大脑转移的属性。 初步研究表明，载体可以表达持续治疗水平的转移GUSB，并分泌的酶在一个大的球体周围的转导位点的校正，这表明该载体可能是适合于长期校正的遗传缺陷。 具体目标是：1）确定对在脑中广泛表达或在神经元中以高水平表达的载体基因表达启动子的影响; 2）表征来自AAV载体的GUSB在脑的各种细胞类型和结构中的表达; 3）定量GUSB在MPS VII脑中的表达的量和寿命，并评估可增加总转导和酶递送的方法;和4）评估长期脑中病理学的变化。 大部分开发和测试将在MPS VII小鼠脑中进行，以优化载体设计和递送策略。 然后，将在MPS VII犬脑中测试该方法，以评价载体性能和较大体积脑组织中的酶扩散。 在人类神经退行性疾病的真实临床模型中进行评价将有助于确定这种方法治疗溶酶体贮积症中CNS疾病的潜力和局限性。

Most genetic diseases that affect the central nervous system (CNS) produce metabolic abnormalities and lesions throughout the brain. Somatic gene transfer is potentially capable of arresting or reversing the disease process in many genetic disorders. However, the methods presently available to transfer genes into the central nervous system generally only deliver a foreign gene to a limited number of cells or to specific structures. A large class of human genetic diseases affecting the CNS are the lysosomal storage disorders, which are characterized by mental retardation and other progressive degenerative abnormalities. The long-term goal of our studies is to develop a method to deliver normal lysosomal enzyme genes into the brain in a manner that can correct the disseminated lesions that are typical of this group of neurodegenerative diseases. In this grant we will study the properties of adeno-associated virus (AAV) vector-mediated transfer of a therapeutic gene, beta-glucuronidase (GUSB), in the brains of GUSB-deficient animal models of mucopolysaccharidosis (MPS) type VII (Sly disease), a representative neurodegenerative storage disease. Preliminary studies demonstrate that the vectors can express sustained therapeutic levels of the transferred GUSB, and secrete the enzyme in a large sphere of correction surrounding the transduction site, suggesting that this vector may be suitable for long-term correction of genetic deficiencies. The Specific Aims are to: 1) Determine the effects on vector gene expression promoters that are expressed widely in the brain or at high levels in neurons; 2) Characterize the expression of GUSB from AAV vectors in various cell types and structures of the brain; 3) Quantitate the amount and longevity of expression of GUSB in the MPS VII brain and evaluate methods which may increase total transduction and enzyme delivery; and 4) Evaluate changes in pathology in the brain over the long-term. Most of the development and testing will be done in the MPS VII mouse brain to optimize the vector designs and delivery strategies. Then, the methods will be tested in the MPS VII dog brain to evaluate vector performance and enzyme diffusion in a larger volume of brain tissue. Evaluation in true clinical models of a human neurodegenerative disease will help define both the potential and limitations of this approach to treating the CNS disease in lysosomal storage disorders.