Defining and treating peripheral nervous system dysfunction in Cln1 disease

摘要： CLN1病或婴儿神经性干酪样脂褐质沉着症(包括婴儿巴顿病)是 起病最早、进展最快的神经性蜡样脂褐素沉着症(NCL或Batten病)。 CLN1病是由溶酶体酶棕榈酰基蛋白硫酯酶-1(PPT1)缺乏引起的，以及 对中枢神经系统(CNS)有毁灭性的影响。症状在生命的第一年就开始了 而且进展很快。CLN1疾病总是致命的，而且没有有效的治疗方法。而当 PPT1缺乏对中枢神经系统的灾难性影响已得到很好的认识，但形式上知之甚少 关于大脑和脊髓以外的疾病表型。除了运动功能的快速下降 患有CLN1疾病的儿童会表现出各种感觉异常，包括疼痛改变，从而导致行动不便 触碰的阈值和过度兴奋。我们来自CLN1疾病小鼠的初步数据表明 表型是由于CLN1疾病对运动和感觉成分的显著影响 以前被忽视的外周神经系统(PNS)。这些损失包括 外周轴突、神经肌肉接头失神经、非髓鞘终末雪旺细胞丢失 复合肌肉动作电位受损，机械刺激阈值改变，背部丧失 根神经节神经元与脊髓背角痛相关神经肽的上调 电源线。这些PNS表型对CLN1疾病预后的贡献还知之甚少，而CNS- 定向治疗不太可能完全治疗这种疾病的PNS表现，它可能会恶化。 随着时间的推移。现在我们将更彻底地描述PNS疾病的程度和性质，然后再测试 能够同时治疗CNS和PNS缺陷的基因治疗策略。我们已经证明了 表达PPT1的AAV2/9载体对新生儿中枢神经系统功能的显著改善 对CLN1病小鼠的作用。我们现在将测试是否将CNS靶向和系统交付相结合 AAV2/9-PPT1将提供比单独使用该载体治疗中枢神经系统更好的治疗结果。我们 将通过以下具体目标实现这些目标。 具体目标1：确定老年人周围神经系统的结构和功能的完整性 CLN1病小鼠。 具体目的2：应用AAV介导的基因治疗周围神经系统疾病。 这些研究将提供有关PPT1缺陷如何影响PNS结构和 对CLN1病小鼠的作用。确定基因疗法治疗这些被低估的疾病的有效性 大脑外PPT1缺乏的后果，将使我们能够改进治疗策略 并为患有CLN1疾病的儿童提供临床上相关的疾病结局。

Abstract: CLN1 disease or Infantile Neuronal Ceroid Lipofuscinosis (INCL or Infantile Batten disease) is one of the earliest onset and most rapidly progressing forms of neuronal ceroid lipofuscinosis (NCL or Batten disease). CLN1 disease is caused by deficiency in the lysosomal enzyme palmitoyl protein thioesterase-1 (PPT1), and has a devastating impact upon the central nervous system (CNS). Symptoms start within the first year of life and progress rapidly. CLN1 disease is always fatal, and there is no effective therapy. While the catastrophic effects of PPT1 deficiency upon the CNS are well appreciated, relatively little is formally known about disease phenotypes outside the brain and spinal cord. In addition to a rapid decline in motor function leading to immobility, children with CLN1 disease display diverse sensory abnormalities including altered pain thresholds and hyperexcitability to touch. Our preliminary data from CLN1 disease mice suggest these phenotypes are due to a pronounced impact of CLN1 disease upon both motor and sensory components of the peripheral nervous system (PNS) that have been previously overlooked. These include loss of peripheral axons, denervation of the neuromuscular junction, loss of non-myelinating terminal Schwann cells and compromised compound muscle action potentials, altered thresholds to mechanical stimuli, loss of dorsal root ganglia neurons and an upregulation of pain-associated neuropeptides in the dorsal horn of the spinal cord. The contribution of such PNS phenotypes to CLN1 disease outcome is poorly understood, and CNS- directed therapies are unlikely to completely treat these PNS manifestations of this disease, which may worsen over time. Now we will more thoroughly characterize the extent and nature of PNS disease before testing a gene therapy strategy capable of treating both CNS and PNS defects. We have already demonstrated that neonatal CNS delivery of an AAV2/9 vector expressing PPT1 remarkably improves brain and spinal cord function in CLN1 disease mice. We will now test whether combining CNS-targeted and systemic delivery of AAV2/9-PPT1 will provide better treatment outcomes compared to treating the CNS alone with this vector. We will achieve these goals with the following specific aims. Specific Aim 1: To determine the structural and functional integrity of the peripheral nervous system in CLN1 disease mice. Specific Aim 2: To treat peripheral nervous system disease with AAV-mediated gene therapy. Together these studies will provide detailed information about how PPT1 deficiency impacts PNS structure and function in CLN1 disease mice. Determining the efficacy of gene therapy to treat these underappreciated consequences of PPT1-deficiency outside the brain, will allow us to refine treatment strategies to improve quality of life and provide clinically relevant disease outcomes for children with CLN1 disease.