Gene transfer & NMR studies in alpha-mannosidosis brain

描述（由申请人提供）：溶酶体贮积症是一组遗传性酶缺陷，会产生致命的退行性综合征，其中大多数影响中枢神经系统。对小鼠疾病模型中的神经干细胞移植和直接基因转移的研究表明，提供正常的酶可以显着减少病理。然而，影响中枢神经系统的代谢疾病通常具有整体性病变，并且大脑内的基因传递相对有限，特别是在大型哺乳动物中。我们已经证明，将 AAV2 载体注射到小鼠脑实质中会导致局部转导，但可以通过分泌介导正常酶的广泛分布。这通过受体介导的内吞作用介导纠正远离转导位点的细胞中的储存损伤。我们最近发现，当AAV2被注射到新生小鼠大脑的侧脑室时，载体通过脑脊液循环广泛分布，导致播散性基因表达。在这个项目中，我们将研究酸性 α-D-甘露糖苷酶 (MANB) 的遗传性缺陷，该缺陷会导致未降解的富含甘露糖的寡糖在细胞溶酶体中积累，尤其是在中枢神经系统 (CNS) 中，从而导致智力低下和其他异常。我们研究了人类疾病猫模型的遗传学、生物化学和病理学，该模型饲养在繁殖群体中。我们将研究 AAV 转导细胞分泌治疗水平酶的能力，并确定转导位点周围可校正的脑组织体积。我们最近还表明，可以通过非侵入性核磁共振（NMR）方法对活体动物中的重要病理进行定量评估。治疗效果将在生前通过临床神经学评估和 MR 进行评估。这些发现将与组织病理学、电子显微镜和生化分析的尸检分析进行比较。猫的α-甘露糖苷中毒是一个模型，用于评估大型哺乳动物大脑中具有播散性病变的中枢神经系统的治疗，其条件类似于治疗人类疾病时遇到的条件。

DESCRIPTION (provided by applicant): The lysosomal storage diseases are a group of inherited enzyme deficiencies that produce fatal degenerative syndromes, most of which affect the CNS. Studies of neural stem cell transplantation and direct gene transfer in mouse disease models have shown that supplying the normal enzyme can significantly reduce pathology. However, metabolic diseases that affect the CNS typically have global lesions and gene delivery within the brain has been relatively limited, particularly in large mammals. We have shown that injection of AAV2 vectors into the parenchyma of the brain in the mouse results in localized transduction, but can mediate widespread distribution of the normal enzyme by secretion. This mediates correction of storage lesions in cells distal from the transduction site, by receptor-mediated endocytosis. We have recently found that when AAV2 is injected into the cerebral lateral ventricles in the newborn mouse brain, the vector becomes widely distributed by the CSF circulation, resulting in disseminated gene expression. In this project we will study an inherited deficiency of acidic alpha-D-mannosidase (MANB), which results in the accumulation of undegraded mannose-rich oligosaccharides in cellular lysosomes, prominently in the central nervous system (CNS), causing mental retardation and other abnormalities. We have studied the genetics, biochemistry, and pathology of a cat model of the human disease, which is maintained in a breeding colony. We will investigate the ability of AAV-transduced cells to secrete therapeutic levels of enzyme and determine the volume of brain tissue that can be corrected surrounding transduction sites. We also have shown recently that there is significant pathology that can be quantitatively evaluated in living animals by non-invasive nuclear magnetic resonance (NMR) methods. The effects of treatment will be evaluated ante-mortem by clinical neurologic assessments and MR. These findings will be compared to post-mortem analysis by histopathology, electron microscopy, and biochemical analyses. The alpha-mannosidosis cat is a model for evaluating treatment of the CNS in a large mammalian brain, with disseminated lesions, under conditions similar to those that will be encountered in treating the human disease.