Next Generation Treatment for Krabbe Disease

Krabbe病（球状细胞脑白质营养不良，GLD）是一种遗传性儿童疾病，由缺乏 溶酶体酶，半乳糖神经酰胺酶（GALC）。在缺乏GALC活性的情况下， 脂质，半乳糖鞘氨醇（psychosine，Psy）积累，并优先导致死亡， 少突胶质细胞Krabbe病影响中枢（CNS）和外周神经系统（PNS），导致 从6个月龄开始出现易怒、感觉退化、运动缺陷、癫痫发作和认知缺陷 死亡发生在2-5岁。目前还没有有效的治疗Krabbe病的方法。在 此外，多年来对克拉布病真实动物模型的研究的所有证据表明， 单次治疗可提供有意义的长期益处。然而，我们最近发现， 治疗方法，同时针对主要致病机制（GALC缺乏症）和 GALC缺乏的继发性后果（精神病积累，炎症等）显着， 协同地增加功效。尽管克拉布病在100多年前就被描述过， 模型已经有近40年的历史，但我们对这种疾病的发病机制知之甚少。 疾病这在很大程度上是交叉校正的混淆效应。我们创造了一种嵌合形式 GALC保留了酶的活性，防止了精神病的积累，并且不能交叉- 纠正周围的细胞。这种新型试剂现在将使我们能够确定交叉- 纠正各种治疗策略和特定细胞类型在Krabbe发病机制中的作用 疾病该提案的目标是：1）确定新开发的底物减少的功效 单独和联合治疗药物，2）确定某些治疗相互作用的机制， 协同增加功效，3）确定特定细胞类型在克拉伯病发病机制中的作用 疾病，以及4）确定精神病产生的机制，并可能发现一种新的 底物减少目标。我们将通过以下具体目标实现这些目标： 目的1：我们将确定CGT特异性SRT药物BMNS 202单独和联合应用的治疗效果。 联合HSCT和AAV介导的基因治疗。 目的2：我们将确定HSCT在与CNS-定向的AAV-1结合时观察到的协同作用中的作用。 在Krabbe病的鼠模型中的介导的基因治疗。 目的3：我们将确定特定细胞类型在Krabbe病发病机制中的作用。 目的4：我们将确定酸性神经酰胺酶在精神碱分解代谢产物中的作用， Krabbe病的发病机制。

Krabbe disease (Globoid-cell leukodystrophy, GLD) is an inherited childhood disease caused by a deficiency in the lysosomal enzyme, galactosyl-ceramidase (GALC). In the absence of GALC activity a highly cytotoxic lipid, galactosyl-sphingosine (psychosine, Psy) accumulates and preferentially causes the death of oligodendrocytes. Krabbe disease affects the central (CNS) and peripheral nervous systems (PNS) leading to irritability, sensory deterioration, motor defects, seizures, and cognitive deficits beginning at 6 months of age and death occurs by 2-5 years of age. There is currently no effective therapy for Krabbe disease. In addition, all the evidence from years of research in authentic animal models of Krabbe disease shows that no single treatment provides meaningful long-term benefits. However, we recently showed that a combination therapy approach that simultaneously targets the primary pathogenic mechanism (GALC deficiency) and secondary consequences of GALC deficiency (psychosine accumulation, inflammation, etc) dramatically and synergistically increases efficacy. Although Krabbe disease was described over 100 years ago and the murine model has been available for nearly 40 years, we know surprisingly little about the pathogenesis of the disease. This is largely to the confounding effects of cross-correction. We have created a chimeric form of GALC that retains enzyme activity, prevents the accumulation of psychosine and is incapable of cross- correcting surrounding cells. This novel reagent will now enable us to determine both the contribution of cross- correction to various therapeutic strategies and the role of specific cell types in the pathogenesis of Krabbe disease. The goals of this proposal are to 1) determine the efficacy of newly developed substrate reduction therapy drugs alone and in combination, 2) determine the mechanism/s by which certain therapies interact to synergistically increase efficacy, 3) determine the role of specific cell types in the pathogenesis of Krabbe disease, and 4) determine the mechanism/s by which psychosine is generated and potentially uncover a new substrate reduction target. We will accomplish these goals with the following Specific Aims: Aim 1: We will determine the therapeutic efficacy of a CGT-specific SRT drug, BMNS202, alone and in combination with HSCT and AAV-mediated gene therapy. Aim 2: We will determine the role of HSCT in the synergy observed when combined with CNS-directed AAV- mediated gene therapy in the murine model of Krabbe disease. Aim 3: We will determine the role of specific cell types in the pathogenesis of Krabbe disease. Aim 4: We will determine the role of acid ceramidase in the catabolic production of psychosine and the pathogenesis of Krabbe disease.