Role of NO in NGF trafficking, kinase phosphorylation and transcription factor activation in cholinergic neurons

乙酰胆碱，通常缩写为ACh，是第一个被发现的神经递质。它参与刺激肌肉，以及神经、身体外和大脑细胞之间的交流。在大脑中，ACh是从参与学习和记忆的细胞中释放出来的，而精神健康问题涉及记忆力丧失，与ACh水平的变化直接或间接相关。这些细胞依靠蛋白质神经生长因子(NGF)生存和维持。NGF结合并激活ACh释放细胞表面一种称为TrkA受体的蛋白质。然后，这种NGF-TrkA复合体被内化并运输到细胞体，在那里它可以调节对这些细胞生存至关重要的基因的表达。调控这些基因表达的机制尚不完全清楚，但很明显，NGF与TrkA的结合是必要的。在拟议的研究中，我们将利用细胞和分子生物学来更好地了解NGF如何增强这些细胞中的基因表达。最近，一氧化氮分子被认为与NGF的这些作用有关，因此我们的具体目的是了解NO如何参与NGF介导的ACh释放细胞的存活。据报道，一氧化氮不仅是一种重要的细胞信使，在某些情况下，它还充当一种神经毒素。为了阐明这些机制，我们建议研究NO在NGF被ACh释放细胞摄取中的作用，NGF-TrkA一旦在这些细胞内激活就会激活的信号事件，以及在维持这些细胞健康所必需的基因表达的调节中的作用。了解NO如何影响基因表达，有助于确定NO在大脑中的保护作用和毒性作用。绘制出在这些细胞中导致基因转录的受体介导的元件将有助于更广泛地理解多个信号通路的激活如何在许多生物过程中导致特定的细胞反应，并可能在诊断测试或治疗的设计中有用，这些诊断测试或治疗将维持脑细胞的健康或阻止细胞丢失的各个方面。

Acetylcholine, often abbreviated as ACh, was the first neurotransmitter to be identified. It is involved in the stimulation of muscle as well as communication in nerves through out the body and between cells in the brain. In the brain, ACh is released from cells that are involved in learning and memory and mental health issues that involve memory loss relate directly or indirectly to alterations in the levels of ACh. These cells depend on the protein nerve growth factor (NGF) for their survival and maintenance. NGF binds to and activates a protein, known as the TrkA receptor on the surface of the ACh-releasing cells. This NGF-TrkA complex then becomes internalized and is transported to the cell body where it can regulate the expression of genes that are critical for the survival of these cells. The mechanisms that regulate the expression of these genes are not completely understood, however it is clear that the binding of NGF to TrkA is necessary. In the proposed studies, we will use cellular and molecular biology to gain a better understanding of how NGF enhances gene expression in these cells. Recently, the molecule nitric oxide has been implicated in these actions of NGF so our specific aim is to understand how NO contributes to the NGF-mediated survival of ACh-releasing cells. Not only has NO has been reported to act as an important cellular messenger, in some situations NO acts as a neurotoxin. In order to elucidate the these mechanisms, we propose to investigate the role of NO in the uptake of NGF into ACh-releasing cells, the signalling events that NGF-TrkA activates once inside these cells and in the modulation of the expression of genes necessary for maintaining the health of these cells. Understanding how NO influences gene expression could be useful in identifying the protective versus toxic effects of NO in the brain. Mapping out the receptor-mediated elements that lead to gene transcription in these cells will contribute to a broader understanding of how activation of multiple signalling pathways can lead to specific cellular responses in a number of biological processes and could be useful in the design of diagnostic tests or therapies that would maintain the health of brain cells or halt aspects of cell loss.