Mechanisms of Early Kidney Development

早期肾脏发育的机制

• 批准号: 6887816
• 负责人: TERI J MAUCH
• 金额: $ 25.56万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6887816
• 关键词: angiogenesis; biological signal transduction; blood vessels; cell cell interaction; ephrins; fluorescent in situ hybridization; growth factor receptors; laboratory mouse; mesoderm; nephrogenesis; polymerase chain reaction; quail; vascular endothelial growth factors; vertebrate embryology; video microscopy

DESCRIPTION (provided by applicant): Recent advances in stem cell technology offer hope that cell therapy and tissue engineering may one day replace renal function lost as a consequence of maldevelopment or disease. Prerequisite to tissue engineering is the understanding of the mechanisms underlying embryonic kidney induction and development. The pronephros arises directly from intermediate mesoderm (IM) and represents the first stage of vertebrate kidney induction. Paraxial mesoderm (PM), which gives rise to somites, induces the pronephros, but the cellular and molecular mechanisms underlying pronephros induction by the PM have not been defined. Somitogenesis and pronephros induction are closely linked to vascular development. The pronephros lies sandwiched between the post-cardinal vein and the aorta in the early embryo, and the PM contains angioblasts. Angioblast-derived signals induce the embryonic heart, pancreas, and liver, suggesting that this may be a general inductive mechanism. Pilot studies showed that inhibition of vasculogenesis decreased expression of the kidney marker, pax-2, in the IM, and suggested that the timing of vascular disruption is important. We hypothesize that molecules secreted by resident angioblasts regulate pronephros induction by the paraxial mesoderm. We know that angioblasts meet the temporal and spatial criteria for a pronephros inducer. In Aim 1, we will define the temporal and spatial appearance of blood vessel precursors in relation to pronephros induction using high-resolution fate mapping. Time-lapse videomicroscopy will follow the development of PM, IM angioblasts, and blood vessels. We will determine whether ectopically induced somites and pronephroi form in association with ectopic blood vessels. Results of these studies will help us understand the details of interactions between angioblasts, PM and IM during their specification. Aim 2 will determine if blood vessel precursors are required for pronephros induction by PM, thereby fulfilling the second criterion for an inducer. We will determine if PM obtained from VEGFR2 (-/-) mice, which lack blood vessels, can induce the pronephros in competent (able to form pronephros) quail mesoderm. Soluble VEGF-R1 will be injected into quail mesoderm to disrupt vasculogenesis, and secondarily, pronephros induction. Aim 3 will determine if blood vessels are sufficient for pronephros induction and thus fulfill the third criterion for an inducer. We will examine the effect of ectopic or excessive blood vessel formation on pronephros induction, and we will recombine embryonic arteries and veins with uninduced competent mesoderm in collagen gel cultures to determine if pronephros induction is specific to a particular vascular type, or is a general feature of blood vessels and angioblasts. The experiments described in this proposal will combine the ease of experimental manipulation of the avian model with the genetic power of mutant mice to define the molecular relationships between blood vessel formation, somitogenesis and pronephros induction.

描述(申请人提供)：干细胞技术的最新进展带来了希望，细胞疗法和组织工程有一天可能取代因发育不良或疾病而丧失的肾功能。组织工程学的前提是了解胚胎肾脏诱导和发育的机制。原肾直接来源于中间中胚层(IM)，代表了脊椎动物肾脏诱导的第一阶段。旁轴中胚层产生体节，诱导原肾，但其诱导原肾的细胞和分子机制尚不清楚。体细胞发生和原肾诱导与血管发育密切相关。在早期胚胎中，前肾夹在隆后静脉和主动脉之间，PM含有血管母细胞。血管母细胞来源的信号诱导胚胎心脏、胰腺和肝脏，表明这可能是一种一般的诱导机制。初步研究表明，抑制血管生成减少了肾脏标记物PAX-2在IM中的表达，并表明血管破裂的时机很重要。我们假设，驻留的血管母细胞分泌的分子调控着旁中胚层对前肾的诱导。我们知道血管母细胞满足前肾诱导剂的时间和空间标准。在目标1中，我们将使用高分辨率命运图来定义与前肾诱导相关的血管前体的时间和空间外观。延时视频显微镜将跟踪PM、IM血管母细胞和血管的发育。我们将确定异位诱导的体节和原肾是否与异位血管相关。这些研究的结果将有助于我们理解血管母细胞、PM和IM在其特化过程中相互作用的细节。目标2将确定PM诱导前肾是否需要血管前体，从而满足诱导剂的第二个标准。我们将确定从缺乏血管的VEGFR2(-/-)小鼠获得的PM是否能在合格的(能够形成前肾的)鹌鹑中胚层诱导出前肾。将可溶性的血管内皮生长因子-R_1注入鹌鹑中胚层，以阻断血管生成，继而诱导前肾。目标3将确定血管是否足以诱导前肾功能，从而满足诱导剂的第三个标准。我们将研究异位或过度血管形成对前肾诱导的影响，我们将在胶原凝胶培养中将胚胎动脉和静脉与未诱导的合格中胚层重组，以确定前肾诱导是特定血管类型所特有的，还是血管和血管母细胞的普遍特征。这项建议中描述的实验将结合鸟类模型实验操作的简便性和突变小鼠的遗传能力，以确定血管形成、体细胞发生和前肾诱导之间的分子关系。