cAMP Signaling in Sympathoadrenal Cell Development

描述(由申请人提供)：拟议研究的长期目标 CAMP和BMP-2信号通路在决定 神经脊(NC)细胞向交感肾上腺(SA)的分化 血统，使用主要的NC文化。在单独的研究中，骨形态发生 蛋白质(BMP-2、BMP-4和BMP-7)和cAMP升高剂可刺激SA 细胞发育，以酪氨酸羟化酶(TH)的表达为特征， 多巴胺B羟化酶(DBH)和儿茶酚胺(CA)的合成。仅限 最近，我们实验室的研究表明，cAMP信号 通路调节影响SA细胞的正负信号 发展。具体地说，在协同作用中，cAMP信号的适度激活 BMP-2促进SA细胞发育并诱导SA表达 血统决定基因Phox2a。相比之下，cAMP的强劲激活 即使在BMP-2存在的情况下，信号也反对SA细胞的发育和 阻断SA谱系决定基因ASH-I和Phox2a的表达。 拟议研究的目标是通过以下方式研究分子机制 其中cAMP在SA细胞发育中起着双峰开关的作用。目标1针对的是 假设低水平的cAMP信号在转录上与 通过协同作用在phox2a基因启动子上传递BMP-2信号 发生在转录因子ASH-I和CREB之间，以及 共激活蛋白CBP。目标2解决了这样的假设，即对抗性 高水平cAMP信号对SA细胞发育的影响涉及 激活MAPK通路，抑制BMP-2激活 超激活剂斯麦德。具体目标是：目标1：确定 骨形态发生蛋白-2与低水平激活cAMP信号的协同作用 SA细胞的发育和Phox2a的表达，与转录 CAMP途径的功能。目标2：定义 高水平激活cAMP信号对骨形成蛋白-2的拮抗作用 介导ASH-I基因表达与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.