AGED FOREBRAIN CHOLINERGIC NEURONS AND NGF DELIVERY

衰老的大脑表现为大脑中胆碱能神经元的退化， 基底前脑，这已被认为是一个重要因素， 与年龄相关的记忆和学习功能下降。 由于这些 神经元依赖于神经生长因子（NGF）来维持 胆碱能表型，已经提出，NGF给药到 大脑可能有助于治疗老年痴呆症， 老年痴呆型 然而，这种分子太大，无法转移 穿过血脑屏障 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）。 一种针对转铁蛋白的抗体（OX-26）， 在BBB血管上以高水平存在的受体， 与NGF分子共价连接：与整个OX-26- NGF结合物发生在脑毛细血管的内皮细胞上。 我们 最近已经证明，静脉注射OX-26-NGF 缀合物显著增强总体生长和胆碱能神经元 眼内医学前脑移植的存活率， 显示形成完整的BBB。 在本提案中，我们将利用 眼内中隔移植物，以获得OX-26-NGF对 1)存活，2）生长和3）胆碱能表型的维持， 衰老过程中的胆碱能神经元 移植手术将被调查 使用针对胆碱乙酰转移酶的抗体， 在光镜和电镜水平上观察到神经生长因子和突触蛋白。 此外，我们建议研究海马移植是否具有 能够产生足够量的内源性NGF以支持 隔共同移植物中的胆碱能神经元，如果这种NGF的产生是 在海马移植物老化过程中减少，以及是否添加 OX-26-NGF偶联物可增加胆碱能神经支配的密度 从中隔到海马的联合移植 最后，将对其进行调查 将OX-26-NGF给予隔-海马双移植物是否可以 在老化过程中增加这种移植物中的胆碱能发芽，或至少 减少这一孤立途径中可能的年龄相关性下降。 很长的- 在实验2和3中的术语组将在嫁接和 短期实验将持续2 - 3个月。 我们假设这些实验将使我们更好地理解 NGF在发育过程中起作用，特别是在隔- 海马系统 此外，我们希望这些发现将有助于 为转铁蛋白受体抗体的潜在用途规划策略- 用于治疗阿尔茨海默氏痴呆患者的NGF缀合物 类型.

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.