Defining and treating peripheral nervous system dysfunction in Cln1 disease

摘要： CLN 1疾病或婴儿神经元蜡样脂褐质沉积症（INCL或婴儿巴滕病）是其中一种 最早发病且进展最快的神经元蜡样脂褐质沉积症（NCL或Batten病）。 CLN 1疾病是由溶酶体酶棕榈酰蛋白硫酯酶-1（PPT 1）的缺乏引起的，并且 对中枢神经系统（CNS）有毁灭性的影响。症状开始于生命的第一年 并且进展迅速。CLN 1疾病总是致命的，并且没有有效的治疗方法。而 PPT 1缺陷对中枢神经系统的灾难性影响是众所周知的，但对它的正式了解相对较少 关于大脑和脊髓以外的疾病表型。除了运动功能迅速下降外 导致不动，CLN 1疾病的儿童表现出多种感觉异常，包括疼痛改变， 阈值和对触摸的过度兴奋。我们从CLN 1疾病小鼠的初步数据表明， 表型是由于CLN 1疾病对运动和感觉成分的显著影响 周围神经系统（PNS）是以前被忽视的。这些损失包括： 外周轴突，神经肌肉接头的去神经支配，非髓鞘化终末雪旺细胞的丢失 和受损的复合肌肉动作电位，改变阈值的机械刺激，损失的背 根神经节神经元和脊髓背角疼痛相关神经肽的上调 线.这种PNS表型对CLN 1疾病结果的贡献知之甚少，CNS- 定向治疗不太可能完全治疗这种疾病的这些PNS表现， 随着时间现在，我们将更彻底地描述PNS疾病的程度和性质，然后再进行测试。 能够治疗CNS和PNS缺陷的基因治疗策略。我们已经证明， 表达PPT 1的AAV 2/9载体的新生儿CNS递送显著改善脑和脊髓 在CLN 1疾病小鼠中的功能。我们现在将测试是否结合CNS靶向和系统性递送 与用该载体单独治疗CNS相比，AAV 2/9-PPT 1将提供更好的治疗结果。我们 将通过以下具体目标实现这些目标。 具体目标1：确定周围神经系统的结构和功能完整性， CLN 1疾病小鼠。 具体目标2：用AAV介导的基因治疗治疗周围神经系统疾病。 这些研究将共同提供有关PPT 1缺陷如何影响PNS结构的详细信息， 在CLN 1疾病小鼠中的功能。确定基因疗法治疗这些被低估的疾病的疗效 PPT 1缺乏症在脑外的后果，将使我们能够改进治疗策略， 生活质量，并为患有CLN 1疾病的儿童提供临床相关的疾病结局。

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.