Regulation of Zebrasfish Development by Semaphorin-Olfactomedin 2 Interactions

描述（由申请人提供）：脑信号蛋白通路在轴突导向中的作用已得到很好的表征。此外，最近的研究结果强调了该途径在其他关键领域的重要作用，如血管发生，血管生成，细胞迁移/分化，免疫调节和癌症病理学。Pi的实验室最近发现了斑马鱼嗅觉调节蛋白2（OM 2），这是一种具有高度保守的嗅觉调节蛋白结构域的分泌型糖蛋白。初步的表达和功能表征研究揭示了OM 2在三个重要的发育过程中的作用：轴突导向，神经嵴迁移/分化和血管生成。与来自中断的脑信号蛋白途径的已发表表型相比，对OM 2变形体的表型的分析一致地导致PI制定以下总体假设：OM 2通过其与脑信号蛋白途径的相互作用调节轴突引导、神经嵴细胞迁移/分化和血管生成。为了测试这些过程中的OM 2-脑信号蛋白通路联系，提出了三个具体目标。具体目标1：为了验证这一假设，即高度特异性颅轴突导向的缺陷，在OM 2的变形是由于干扰的直接相互作用OM 2和脑信号蛋白受体复合物。具体目标二：为了检验以下假设，即OM 2变形体中咽软骨的缺失是由于颅神经嵴细胞（cNCC）迁移和/或分化的扰动，这严重依赖于脑信号蛋白途径。具体目标3：为了检验这一假设，即高度特异性的缺陷，发现只有在晚发型颅血管的OM 2变形是由于干扰脑信号蛋白-神经纤毛蛋白和/或VEGF-神经纤毛蛋白途径。 这些假设将通过（1）OM 2和脑信号蛋白信号传导分子的高分辨率表达分析来检验，其缺陷导致与OM 2缺陷表型高度相似的表型;（2）脑信号蛋白组分和OM 2的伴随抑制以验证OM 2在脑信号蛋白信号传导途径中的功能会聚;（3）测试OM 2与脑信号蛋白受体复合物的组分之间的直接分子相互作用。鉴于已知脑信号蛋白通路与成人神经再生、颅面畸形（最常见的人类出生缺陷）和肿瘤血管生成密切相关，因此对该信号通路调控的新见解将具有至关重要的健康益处。

DESCRIPTION (provided by applicant): Semaphorin pathways have been well characterized for their roles in axon guidance. Moreover, recent findings highlight significant roles of this pathway in other critical areas such as vasculogenesis, angiogenesis, cell migration/differentiation, immune regulation, and cancer pathology. The Pi's laboratory has recently identified zebra fish olfactomedin 2 (OM2), a secreted glycoprotein with a highly conserved olfactomedin domain. Initial expression and functional characterization studies revealed OM2's roles in three important developmental processes: axon guidance, neural crest migration/differentiation, and angiogenesis. Analyses on phenotypes of OM2 morphants in comparison with published phenotypes from disrupted semaphorin pathways, consistently led the PI to formulate the following overall hypothesis: OM2 regulates axon guidance, neural crest cell migration/differentiation, and angiogenesis via its interaction with the semaphorin pathway. In order to test the OM2-semaphorin pathway link in these processes, three Specific Aims are proposed. Specific Aim 1: To test the hypothesis that highly specific cranial axon guidance defects in OM2 morphants are due to the perturbation of direct interaction between OM2 and semaphorin receptor complexes. Specific Aim 2: To test the hypothesis that the absence of pharyngeal cartilages in OM2 morphants is due to the perturbation of cranial neural crest cell (cNCC) migration and/or differentiation, which is critically dependent upon semaphorin pathways. Specific Aim 3: To test the hypothesis that highly specific defects found only in late-onset cranial vasculature in OM2 morphants are due to perturbation in semaphorin-neuropilin and/or VEGF-neuropilin pathways. These hypotheses will be tested by (1) high resolution expression analysis of OM2 and semaphorin signaling molecules, deficiency of which results in highly similar phenotypes as OM2-deficiency phenotypes; (2) concomitant inhibition of semaphorin components and OM2 to verify functional convergence of OM2 in the semaphorin signaling pathway; (3) testing direct molecular interactions between OM2 and components of the semaphorin receptor complex. Given that the semaphorin pathway is known to be critically involved in adult nerve regeneration, craniofacial malformation (most frequent human birth defects), and tumor angiogenesis, novel insights into the regulation of this signaling pathway will be of paramount health benefit.