FELINE NIEMANN - PICK TYPE C

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。在NCRR P40拨款的支持下，宾夕法尼亚大学兽医学院将唯一一群患有尼曼-皮克C型疾病(NPC)的猫转移到了宾夕法尼亚大学兽医学院。鼻咽癌基因点突变是导致猫的临床症状的原因。跨膜NPC1蛋白的遗传缺陷导致神经内脏胆固醇-神经鞘糖脂沉积症，其特征是严重和进行性的认知和运动障碍，以及癫痫发作和肝脾肿大。本病的代谢基础尚不完全清楚，但NPC1蛋白的缺乏导致内吞胆固醇在细胞内的异常转运，以及由于未酯化的胆固醇和神经节苷脂(乳糖基神经酰胺、葡萄糖神经酰胺和神经节苷脂)储存在溶酶体和晚期内酶体中而导致细胞肿胀。神经节苷脂，特别是GM2神经节苷脂在神经元中的储存导致皮质锥体神经元以及屏状核和杏仁核的多极细胞上形成巨细胞和异位树突形成。大脑的神经病理还包括浦肯野细胞死亡、GABA能神经元轴突球体形成、脱髓鞘和由tau蛋白组成的神经原纤维缠结。在鼻咽癌猫身上进行的研究对于确定GABA能神经元中轴突球体的形成以及神经轴突营养不良与神经功能障碍的相关性至关重要。我们还利用鼻咽癌猫科动物模型来鉴定神经节苷脂GM2和GM3的晚期内体/溶酶体积聚，以及GM2的储存与巨核细胞的形成和树突状细胞的异常形成的关系。为了研究神经鞘糖脂的储存对鼻咽癌疾病的影响，对3只鼻咽癌猫预先给予N-丁基脱氧诺吉霉素(NB-DNJ)治疗，N-丁基脱氧诺吉霉素(NB-DNJ)是包括乳糖基神经酰胺和神经节苷脂在内的所有基于葡萄糖神经酰胺的糖鞘脂的抑制剂。鼻咽癌猫每天服用NB-DNJ 23-54天后，意向性震颤和共济失调的发作延迟，小白蛋白阳性轴突球体减少，Calbindin阳性浦肯野细胞数量增加，脑神经节苷脂积累减少，寿命延长。这项研究强调了鞘糖脂储存在疾病进展中的重要性，是第一种有效缓解鼻咽癌疾病进展的疗法。正在进行研究，以进一步确定猫模型鼻咽癌疾病的神经系统疾病的进展，使用神经学检查、电诊断测试、核磁共振成像(核磁共振)、生物化学和组织病理学。在这些研究的同时，我们正在评估N-丁基脱氧诺吉霉素、神经类固醇别孕酮以及别孕酮和N-丁基脱氧诺吉霉素联合治疗猫鼻咽癌神经系统疾病的疗效。我们推测，用这些药物治疗鼻咽癌猫将延迟神经功能障碍体征的出现，改善电诊断和核磁共振异常，延长寿命，提高浦肯野细胞存活率，并减少神经节苷脂在脑中的储存。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The only colony of cats with Niemann-Pick type C disease (NPC) was moved to the School of Veterinary Medicine of the University of Pennsylvania from Colorado State University using support from the NCRR P40 grant. A point mutation in the NPC gene is responsible for clinical signs in cats. Genetic deficiency of the transmembrane NPC1 protein results in a neurovisceral cholesterol-glycosphingolipidosis, which is characterized by severe and progressive cognitive and motor deficits in addition to seizures and hepatosplenomegaly. The metabolic basis of this disease is not fully understood but deficiency in NPC1 protein results in the abnormal intracellular transport of endocytosed cholesterol, and in cellular swelling due to the storage of unesterified cholesterol and glycosphingolipids (lactosylceramide, glucosylceramide, and gangliosides) in lysosomes and late endosomes. The storage of gangliosides in neurons, specifically GM2 ganglioside, results in meganeurite formation and ectopic dendritogenesis on cortical pyramidal neurons and multipolar cells of the claustrum and amygdala. Neuropathology of the brain also includes Purkinje cell death, axonal spheroid formation of GABAergic neurons, demyelination, and neurofibrillary tangles composed of tau protein. Studies performed in the NPC cat were critical for identifying axonal spheroid formation in GABAergic neurons and the correlation of neuroaxonal dystrophy with neurological dysfunction. The feline model of NPC disease was also used to identify the late endosomal/lysosomal accumulation of GM2 and GM3 gangliosides and unesterified cholesterol as well as the association of GM2 storage with meganeurite formation and abnormal dendritogenesis. To examine the effect of glycosphingolipid storage on NPC disease, three NPC cats were previously treated with N-bultyldeoxynojirimycin (NB-DNJ), an inhibitor of all glucosylceramide-based glycosphinglipids including lactosylceramide and the gangliosides. NPC cats treated with NB-DNJ daily for 23 to 54 days showed a delay in the onset of intention tremor and ataxia, diminished Parvalbumin-positive axonal spheroids, increased numbers of Calbindin-positive Purkinje cells, a reduction in brain ganglioside accumulation, and an increase in life span. This study underscored the importance of glycosphingolipid storage on disease progression and was the first therapy to effectively ameliorate disease progression in any species with NPC disease. Studies are being performed to further define the progression of nervous system disease in the feline model NPC disease using neurological examination, electrodiagnostic testing, nuclear magnetic resonance imaging (NMR), biochemistry, and histopathology. Concurrent with these studies we are evaluating the efficacy of N-butyldeoxynojirimycin, the neurosteroid allopregnanolone, and the combination of allopregnanolone and N-butyldeoxynojirimycin, to treat nervous system disease in feline NPC. We hypothesize that the treatment of NPC cats with these drugs will delay the onset of signs of neurological dysfunction, improve electrodiagnostic and NMR abnormalities, increase lifespan, increase Purkinje cell survival, and decrease ganglioside storage in the brain.