DEVELOPMENTAL REGULATION OF ANGIOTENSIN II VASCULAR MITOGENESIS

血管紧张素 II 血管有丝分裂的发育调节

• 批准号: 6272393
• 负责人: Susan P Bagby
• 金额: $ 16.91万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-06-01 至 1999-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6272393
• 关键词: angiotensin II; cell cycle; cell differentiation; cell growth regulation; embryogenesis; epidermal growth factor; gestational age; growth factor receptors; heart cell; hemodynamics; hormone receptor; hormone regulation /control mechanism; immunoprecipitation; mammalian embryology; mitogen activated protein kinase; mitogens; muscle cells; northern blottings; phenotype; renin angiotensin system; swine; tissue /cell culture; transforming growth factors; vascular smooth muscle; western blottings

Angiotensin II is a potent vasoconstrictor which also induces growth in vascular smooth muscle cells (VSMC). Evidence supports an essential role for AngII in fetal/neonatal vasculogenesis. We have shown in adult porcine aortic VSMC the AngII mitogenic action is incomplete, confined to late cell-cycle events: AngII induces completion of cell division by cells reversibly arrested in G2 Phase but has no capacity to stimulate or protein DNA synthesis. In contrast, based on our preliminary results, AngII potently stimulated DNA and protein synthesis and increased cell proliferation rate in neonatal porcine VSMC. This, together with published evidence that the full mitogenic response to AngII in human fetal mesangial cells is lost with aging, prompts our HYPOTHESIS that AngII mitogenic capacity is developmentally regulated. Using our established porcine VSMC model, we will test this in inbreed microswine, permitting control of precisely-timed fetal and neonatal tissues, reducing nonspecific genetic variability, and reducing number of passages in culture by pooling of VSMC from sex-matched littermates. Our three SPECIFIC AIMS each address VSMC obtained from fetal, neonatal, vs. post- pubertal microswine and studied at matched subconfluent density in 3rd- 5th passage. In SA#1, we will determine for each developmental stage the early cell-cycle vs. late cell-cycle loci of AngII mitogenic actions in (respectively) G0- or G2-synchronized VSMC using a newly validated synchronization protocol. In SA#2, we will assess developmental regulation of AngII receptor number, subtype, and AT-1:AT-2 ratio and determine the functional role of each subtype in the mitogenic actions of AngII defined at each developmental age. In SA#3, based on the importance of the Epidermal Growth Factor (EGF) receptor in fetal development and its capacity to increase AT and decrease AT-2 AngII receptors, we will determine the role of constitutive EGF-R number and activation status in the developmental regulation of AngII mitogenic capacity and will and compare effects of chronic "priming" with Transforming Growth Factor (TGF) alpha, the dominant fetal ligand for EGF receptor activation, on basal growth, on mitogenic responses to AngII, and on both Ang II receptors (AT- 1 and AT-2) and EGF-R in VSMC from each developmental stage. Because a fetal-like phenotype can be re-induced in mature VSMC in response to injury, understanding the developmental physiology of vascular growth regulation has relevance not only to normal growth, but also to preventive/therapeutic interventions in both children and adults at risk for vascular disease.

血管紧张素II是一种强有力的血管收缩剂， 血管平滑肌细胞（VSMC）。 有证据表明， 胎儿/新生儿血管生成中的血管生成素II。 我们在成人中展示了 猪主动脉VSMC的AngII促有丝分裂作用是不完全的，局限于 晚期细胞周期事件：AngII通过以下方式诱导细胞分裂完成： 细胞可逆地停滞在G2期，但没有能力刺激或 蛋白质DNA合成 相比之下，根据我们的初步结果， 血管紧张素Ⅱ能有效地刺激DNA和蛋白质的合成， 新生猪血管平滑肌细胞增殖率。 再加上 已发表的证据表明，人类对AngII的完整促有丝分裂反应 随着年龄的增长，胎儿系膜细胞丢失，提示我们的假设， AngII促有丝分裂能力是发育调节的。 使用我们 建立了猪VSMC模型，我们将在近交系微型猪中进行测试， 允许精确定时控制胎儿和新生儿组织， 非特异性遗传变异，并减少传代次数， 通过合并来自性别匹配的同窝仔的VSMC进行培养。 我们的三 具体目标分别涉及从胎儿、新生儿和产后获得的VSMC。 青春期小型猪，并在第3- 第五段。 在SA#1中，我们将确定每个发展阶段的 血管紧张素II促有丝分裂作用的早期细胞周期与晚期细胞周期位点， （分别）使用新验证的G 0或G2同步VSMC 同步协议。 在SA#2中，我们将评估发展 调节AngII受体数量、亚型和AT-1：AT-2比例， 确定每种亚型在促有丝分裂作用中的功能作用， AngII在每个发育年龄定义。 在SA#3中，基于 表皮生长因子（EGF）受体在胎儿发育及其 增加AT和减少AT-2 AngII受体的能力，我们将 确定组成型EGF-R数量和激活状态在 AngII促有丝分裂能力和意志的发育调节， 比较慢性“引发”与转化生长因子（TGF）的作用 EGF受体激活的主要胎儿配体α，在基础 生长，对AngII的促有丝分裂反应，以及对两种AngII受体（AT- 1和AT-2）和EGF-R的表达。 因为 胎儿样表型可以在成熟VSMC中重新诱导， 了解血管生长的发育生理学 监管不仅与正常增长有关， 对高危儿童和成人的预防/治疗干预 治疗血管疾病