AGED FOREBRAIN CHOLINERGIC NEURONS AND NGF DELIVERY

衰老的大脑表现出胆碱能神经元的退化。 基底前脑，已被认为是一个重要的因素 与年龄相关的记忆和学习功能下降。因为这些 神经元依赖神经生长因子(NGF)维持 胆碱能表型，已被认为，NGF进入 大脑可能有助于治疗与年龄相关的痴呆 老年痴呆症。然而，这种分子太大了，无法转移 穿过血脑屏障的任何显著数量。我们有 最近记录了一种通过血液输送NGF的新方法- 脑屏障(BBB)。针对转铁蛋白的抗体(OX-26) 在血脑屏障血管上高水平存在的受体是 与NGF分子共价连接：与整个OX-26- NGF偶联物存在于大脑毛细血管内皮细胞中。我们 最近证明了使用OX-26-NGF静脉治疗 结合物显著促进整体生长和胆碱能神经元 眼内医用前脑移植的存活率 显示出发育完好的血脑屏障。在本提案中，我们将利用 眼内隔膜移植获得OX-26-NGF的量效关系曲线 1)存活，2)生长，3)胆碱能表型的维持 胆碱能神经元的衰老过程。将对移植进行调查 利用针对胆碱乙酰转移酶的抗体，受体 NGF和突触素蛋白在光镜和电子显微镜下均有表达。 此外，我们建议调查海马区移植是否有 能够产生足够数量的内源性NGF以支持 隔膜联合移植中的胆碱能神经元，如果这种NGF产生是 在老化过程中海马区移植物的减少，以及是否添加 OX-26-NGF偶联物可增加胆碱能神经支配密度 从隔区到海马区的联合移植。最后，将对其进行调查 OX-26-NGF在隔区-海马区双侧移植物中的应用 在老化过程中增加这种移植物中的胆碱能萌发，或者至少 在这条孤立的通路中，减少可能与年龄相关的下降。长的- 实验2和实验3中的分期组从嫁接到 评估，而短期试验将持续2-3个月。 我们假定这些实验将使我们更好地理解 NGF在发育过程中发挥作用，特别是在隔膜的衰老过程中。 海马体系统。此外，我们希望这些调查结果将有助于 计划转铁蛋白受体抗体的潜在使用策略- 神经生长因子结合物治疗阿尔茨海默病痴呆 打字。

The aging brain manifests a deterioration of cholinergic neurons in the basal forebrain, which has been suggested to be one important factor for age-related decreases in memory and learning functions. Since these neurons are dependent on nerve growth factor (NGF) for maintenance of cholinergic phenotype, it has been suggested, that NGF administration into the brain might aid in the treatment of age-related dementias of the Alzheimer type. However, this molecule is too large to be transferred across the blood-brain barrier in any significant amounts. We have recently documented a novel approach for delivering NGF across the blood- brain barrier (BBB). An antibody (OX-26) directed against transferrin receptors, which are present at high levels on the BBB vessels, is covalently linked to the NGF molecule: Transcytosis with the entire OX-26- NGF conjugate occurs across the endothelial cells of brain capillaries. We have recently demonstrated that intravenous treatment with the OX-26-NGF conjugate significantly enhances both overall growth and cholinergic neuron survival in intraocular medical forebrain transplants, which have been shown to develop an intact BBB. In the present proposal we will utilize intraocular septal grafts to obtain a dose-response curve for OX-26-NGF on 1) survival, 2) growth, and 3) maintenance of cholinergic phenotype in cholinergic neurons during aging. The transplants will be investigated using antibodies directed against choline acetyltransferase, receptors for NGF and synapsin protein at both light and electron microscopic level. Furthermore, we propose to investigate if hippocampal transplants have the ability to produce sufficient amounts of endogenous NGF to support cholinergic neurons in septal co-grafts, if this NGF production is decreased during aging in hippocampal grafts, and whether the addition of OX-26-NGF conjugate can increase the density of cholinergic innervation from septal to hippocampal co-grafts. Finally, it will be investigated whether administration of OX-26-NGF to septal-hippocampal double grafts can increase cholinergic sprouting in such grafts during aging or at least diminish possible age-related declines in this isolated pathway. The long- term groups in experiment 2 and 3 will take 2 years between grafting and evaluation, while the short-term experiments will stretch over 2-3 months. We postulate that these experiments will lead to a greater understanding of NGF functions during development and especially during aging in the septo- hippocampal system. Furthermore, we hope that these findings will aid in planning the strategy for potential use of transferrin receptor antibody- NGF conjugates for treatment of patients with dementias of the Alzheimer type.