Non-invasive gene therapy for inherited neurodegenerative disorders (How to cross the BBB?)

非侵入性基因治疗遗传性神经退行性疾病如异染性脑白质营养不良（MLD）的可行性已被研究。甘露糖-6-磷酸受体（M6 PR）在溶酶体酶跨血脑屏障的交叉校正和转胞吞中起重要作用。M6 PR是一种多功能细胞表面受体，也与胰岛素样生长因子II（IGF-II）相互作用，由15个重复结构域组成。我们克隆了7.6kb的M6 PR cDNA，并构建了一系列小基因。含有结构域1至9的4.8kb小基因显示结合M6 P而不结合IGF-II。利用含有4.8kb小基因的慢病毒载体，M6 PR可以在各种细胞系和动物模型的组织中表达。M6 PR表达载体可用于研究溶酶体酶的亚细胞定位和运输，以及提高酶替代疗法对溶酶体疾病的疗效。在另一种方法中，我们研究了鞘内（IT）注射腺相关病毒载体血清型1（AAV 1）治疗MLD的可行性。将表达芳基硫酸酯酶A（阿萨）或绿色荧光蛋白（GFP）的AAV 1载体鞘内注射到阿萨敲除的MLD模型小鼠中。在整个脑中观察到GFP表达的广泛分布。此外，在脊髓背侧的大量神经纤维和背根神经节中的许多神经细胞体被有效地转导。阿萨活性的广泛分布和硫苷脂含量的显着降低被证实在治疗的MLD模型小鼠。IT注射AAV 1载体是一种有用的和非侵入性的方法，用于广泛的基因递送到大脑和背根神经节。

The feasibility of non-invasive gene therapy for inherited neurodegenerative disorders like metachromatic leuko dystrophy (MLD) has been investigated. Mannose-6-phosphate receptor (M6PR) plays important roles in both corss-correction and transcytosis across the blood brain barrier of lysosomal enzymes. M6PR is a multifunctional cell surface receptor which also interacts with insulin-like growth factor II (IGF-II) and is composed of 15 repeated domains. We have cloned 7.6kb M6PR cDNA and constructed a series of minigenes. The 4.8kb minigene containing domain 1 to 9 was shown to bind M6P but not IGF-II. Using a lentiviral vector containing the 4.8kb minigene, M6PR can be expressed in various cell lines and tissues of animal models. M6PR expression vector should be useful for studying subcellular localization and trafficking of lysosomal enzymes and for enhancing the efficacy of enzyme replacement therapy for lysosomal disorders. In an alternative approach, we examined the feasibility of intrathecal (IT) injection of adeno-associated viral vector serotype 1 (AAV1) to treat MLD. AAV1 vector expressing arylsulfatase A (ASA) or green fluorescence protein (GFP) was intrathecally injected into ASA knockout MLD model mice. Broad distribution of GFP expression was seen throughout the brain. In addition, a large number of nerve fibers in the dorsal spinal cord and many neural cell bodies in the dorsal root ganglia were efficiently transduced. Widespread distribution of ASA activity and significant reduction of sulfatide content were confirmed in treated MLD model mice. IT injection of AAV1 vector is a useful and noninvasive method for widespread gene delivery to the brain and dorsal root ganglia.