Manipulating N-acetyl-L-aspartate to reverse Canavan leukodystrophy

Canavan病是一种尚未治愈的婴儿和儿童脑白质营养不良，其中ASPA 突变阻止了功能性腺苷酸酰化酶的脑表达。天冬氨酸酰化酶是必需的 大脑中丰富的氨基酸N-乙酰基-L-天冬氨酸（NAA）的分裂;因此，大脑 NAA浓度在卡纳万病中显著升高。该项目将评估 Canavan病中过量NAA的脑分布不均导致 脑空泡变性并导致延迟的脑神经元损失。我们之前的工作提供了 这一假说的一些支持;我们报告了组成性缺失或新生儿脑 敲低编码神经元NAA合成酶N-乙酰转移酶的Nat 8l 8-样，防止脂肪酰化酶缺陷的Canavan模型小鼠幼仔发育成空泡 脑白质营养不良而且，在初步研究中，我们已经表明，脑池内注射 抗Nat 81单链锁核酸反义寡核苷酸（“Nat 81缺口体”）， 年轻的成年Canavan模型小鼠逆转了其预先存在的共济失调和空泡小脑 退化具体目标1将确定基于Nat 8l缺口体的治疗方案是否 可以设计，这将提供成年Canavan模型小鼠长期保护， 空泡性脑白质营养不良和神经元缺失。如果是这样，这种方法可能适用于婴儿 和有症状的卡纳万病儿童。具体目标2的重点是假设， Canavan模型小鼠的空泡性脑白质营养不良是可预防和可逆的， 星形胶质细胞内NAA过度积累。我们将检验一个基于这一假设的预测， Canavan模型小鼠中的空泡性脑白质营养不良可以分别通过以下方法预防或逆转： 组成性或星形胶质细胞条件性Slc 13 a3缺失; Slc 13 a3编码质膜 由星形胶质细胞表达的钠偶联二羧酸协同转运蛋白（NaDC 3），具有高亲和力 对于NAA。该目的的阳性结果将鉴定Slc 13 a3和NaDC 3为新的Canavan 疾病治疗目标。

Canavan disease is an as yet incurable leukodystrophy of infancy and childhood, in which ASPA mutations prevent brain expression of functional aspartoacylase. Aspartoacylase is required for cleavage of the abundant brain amino acid N-acetyl-L-aspartate (NAA); hence, the brain concentration of NAA becomes massively elevated in Canavan disease. This project will evaluate the fundamental hypothesis that brain maldistribution of excess NAA in Canavan disease causes brain vacuolar degeneration and leads to delayed brain neuron loss. Our prior work provided some support for this hypothesis; we reported that constitutive deletion or neonatal brain knockdown of Nat8l, which encodes the neuronal NAA-synthesizing enzyme N-acetyltransferase 8-like, prevents aspartoacylase-deficient Canavan model mouse pups from developing vacuolar leukodystrophy. And, in preliminary studies, we’ve shown that intracisternal administration of an anti-Nat8l single-stranded locked nucleic acid antisense oligonucleotide (“Nat8l gapmer”) to young adult Canavan model mice reverses their pre-existing ataxia and vacuolar cerebellar degeneration. Specific Aim 1 will determine whether an Nat8l gapmer-based treatment regimen can be devised that will provide adult Canavan model mice with long-term protection against vacuolar leukodystrophy and neuron loss. If so, this approach might be translatable to infants and children with symptomatic Canavan disease. Specific Aim 2 focuses on the hypothesis that vacuolar leukodystrophy in Canavan model mice is preventable and reversible by inhibiting astroglial over-accumulation of NAA. We will test a prediction, based on this hypothesis, that vacuolar leukodystrophy in Canavan model mice can be prevented or reversed, respectively, by constitutive or astroglial conditional Slc13a3 deletion; Slc13a3 encodes a plasma membrane sodium-coupled dicarboxylate cotransporter (NaDC3) expressed by astroglia that has high affinity for NAA. A positive result in this aim would identify Slc13a3 and NaDC3 as novel Canavan disease therapeutic targets.