Mechanism of cGMP-Mediated Vasodilation in Perinatal Lung

cGMP 介导的围产期肺血管舒张机制

• 批准号: 6773918
• 负责人: J. Usha RAJ
• 金额: $ 48.51万
• 依托单位: LUNDQUIST INSTITUTE FOR BIOMEDICAL INNOVATION AT HARBOR-UCLA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6773918
• 关键词: RNA binding protein; SDS polyacrylamide gel electrophoresis; autoradiography; cGMP dependent protein kinase; cyclic GMP; densitometry; enzyme activity; free radical oxygen; hypoxia; immunoprecipitation; lung development; messenger RNA; nitric oxide; oxygen; perinatal; peroxynitrites; phosphorylation; protein biosynthesis; protein degradation; pulmonary circulation; regulatory gene; sheep; vascular smooth muscle; vasodilation; western blottings

DESCRIPTION (provided by applicant): We and others have established that the endothelium derived nitric oxide-guanylyl cyclase-cGMP pathway is an important mechanism of vasodilation in the pulmonary circulation during the transition from fetal to newborn state. Our laboratory was first to establish that cGMP-dependent protein kinase (PKG) is critically important for mediating the action of cGMP in the pulmonary circulation. We have also shown that cAMP can cross-activate PKG and thus it appears that PKG mediates the vasodilator action of both cyclic nucleotides. An important signal for the pulmonary vasculature to dilate at birth is the abrupt increase in oxygen tension. We have data to show that when fetal pulmonary vessels are exposed to increased oxygen, there is an increase in PKG activity leading to an enhanced dilator response to cGMP. Our preliminary data show that exposure of ovine fetal pulmonary vascular smooth muscle cells (PVSMC) to increased oxygen results in: 1. An increase in PKG kinase activity, 2. An increase in PKG protein levels, as well as 3. An increase in PKG mRNA levels. Our hypothesis is that at birth, oxygen up-regulates PKG protein levels and PKG kinase activity, thereby facilitating pulmonary vasodilation and a smooth neonatal transition. Our aims are: 1. To investigate how oxygen regulates PKG kinase activity in PVSMC; 2. To determine the effect of oxygen on PKG protein levels in PVSMC; and 3. To investigate two mechanisms of regulation of PKG protein and mRNA levels in PVSMC. Experiments will be done in ovine fetal PVSMC from arteries and veins. We will also use isolated ovine fetal intrapulmonary arteries and veins, to model the experiments with PVSMC, so that we can determine the physiological significance of the in vitro biochemical data. Our overall goal is to gain a better understanding of the unique biological processes by which pulmonary vasomotor tone is regulated in the perinatal period and to understand the role of PKG in this process. Knowledge derived from our studies should enable us to develop new prevention and treatment strategies for disorders of pulmonary vasomotor control at birth such as Persistent Pulmonary Hypertension of the Newborn.

描述（由申请人提供）：我们和其他人已经证实，内皮来源的一氧化氮-胍基环化酶- cgmp途径是胎儿到新生儿状态过渡期间肺循环血管舒张的重要机制。我们的实验室首先确定cGMP依赖性蛋白激酶（PKG）在肺循环中介导cGMP的作用至关重要。我们还表明cAMP可以交叉激活PKG，因此PKG似乎介导了两种环核苷酸的血管舒张作用。出生时肺血管扩张的一个重要信号是氧张力的突然增加。我们有数据表明，当胎儿肺血管暴露于氧气增加时，PKG活性增加，导致扩张剂对cGMP的反应增强。我们的初步数据表明，绵羊胎儿肺血管平滑肌细胞（PVSMC）暴露于增加的氧气会导致：1。PKG激酶活性增加，2。PKG蛋白水平升高，3。PKG mRNA水平升高。我们的假设是，在出生时，氧气上调PKG蛋白水平和PKG激酶活性，从而促进肺血管扩张和新生儿顺利过渡。我们的目标是：1；探讨氧对PVSMC PKG激酶活性的调控作用；2. 探讨氧对PVSMC PKG蛋白水平的影响；和3。探讨PKG蛋白和mRNA水平在PVSMC中的调控机制。实验将在绵羊胎儿动脉和静脉中进行。我们还将使用离体羊胎肺内动静脉，用PVSMC对实验进行建模，从而确定体外生化数据的生理意义。我们的总体目标是更好地了解围产期肺血管舒缩张力调节的独特生物学过程，并了解PKG在这一过程中的作用。从我们的研究中获得的知识应该使我们能够制定新的预防和治疗策略，以预防和治疗新生儿持续性肺动脉高压等出生时肺血管舒缩控制障碍。