cAMP Signaling in Sympathoadrenal Cell Development

描述（由申请方提供）：拟定研究的长期目标 阐述了cAMP和BMP-2信号通路在决定 神经嵴（NC）细胞向交感肾上腺（SA）细胞的分化 谱系，采用原代NC培养。在单独的研究中，骨形态发生 蛋白质（BMP-2、4和7）和cAMP升高剂显示刺激SA 细胞发育，其特征在于酪氨酸羟化酶（TH）的表达， 多巴胺B-羟化酶（DBH）和儿茶酚胺（CA）的合成。只 最近，我们实验室的研究表明， 信号通路调节影响SA细胞的正性和负性信号 发展具体地，在协同作用下， 与BMP-2一起，促进SA细胞发育并诱导SA的表达， 谱系决定基因Phox 2a。相比之下，cAMP的强烈激活 即使在BMP-2存在的情况下，信号传导也会抑制SA细胞的发育， 阻断SA谱系决定基因ASH-I和Phox 2a的表达。 拟议研究的目的是通过以下方式研究分子机制： 其中cAMP在SA细胞发育中充当双峰开关。目标1针对 假设低水平cAMP信号传导在转录上与 通过协同相互作用在phox 2a基因启动子处的BMP-2信号传导 发生在转录因子ASH-i和CREB之间， 共激活蛋白CBP。目的2解决了拮抗剂 高水平cAMP信号对SA细胞发育的影响涉及 MAPK通路的激活，影响BMP-2激活的 反式激活因子SMAD。具体目标是：目标1：确定 BMP-2和cAMP信号传导低水平活化之间的协同作用， SA细胞的发育和Phox 2a的表达，与转录调控有关。 cAMP途径的功能。目标2：确定 高水平激活cAMP信号对BMP-2的拮抗作用 介导的ASH-I基因表达和SA细胞发育。

DESCRIPTION (provided by applicant): The long-term goal of the proposed studies addresses the interplay of the cAMP and BMP-2 signaling pathways in determining the differentiation of Neural Crest (NC) cells to the sympathoadrenal (SA) lineage, employing primary NC cultures. In separate studies, bone morphogenetic proteins (BMP-2, 4 and 7) and cAMP elevating agents were shown to stimulate SA cell development, characterized by the expression of tyrosine hydroxylase (TH), dopamineB-hydroxylase (DBH) and the synthesis of catecholamines (CA). Only recently, studies from our laboratory demonstrated that the cAMP signaling pathway modulates both positive and negative signals which influence SA cell development. Specifically, moderate activation of cAMP signaling, in synergy with BMP-2, promotes SA cell development and induces the expression of the SA lineage-determining gene Phox2a. By contrast, robust activation of cAMP signaling opposes, even in the presence of BMP-2, SA cell development and blocks the expression of the SA lineage-determining genes ASH-I and Phox2a. The objectives of the proposed studies investigate the molecular mechanisms by which cAMP acts as a bimodal switch on SA cell development. Aim 1 addresses the hypothesis that low-level cAMP signaling synergizes transcriptionally with BMP-2 signaling at the phox2a gene promoter, via synergistic interactions occurring between the transcription factors ASH-i and CREB, and the co-activator protein CBP. Aim 2 addresses the hypothesis that the antagonistic effect of high-level cAMP signaling on SA cell development involves the activation of the MAPK pathway, effecting the inhibition of the BMP-2-activated transactivators SMADs. The Specific Aims are: Aim 1: To determine whether the synergistic effect between BMP-2 and low-level activation of cAMP signaling, on SA cell development and Phox2a expression, is linked to the transcriptional function of the cAMP pathway. Aim 2: To define the mechanism of the antagonistic effect of high-level activation of cAMP signaling on the BMP-2 mediated ASH-I gene expression and SA cell development.