Regulation of pulmonary circulation in fetus and newborn

胎儿和新生儿肺循环的调节

• 批准号: 6682093
• 负责人: GIRIJA G. KONDURI
• 金额: $ 21.25万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-05-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6682093
• 关键词: adenosine triphosphate; congenital cardiovascular disorder; enzyme activity; erythrocytes; genetic transcription; heat shock proteins; intermolecular interaction; neurotransmitter biosynthesis; neurotransmitter receptor; newborn animals; nitric oxide synthase; oxidative phosphorylation; oxygen tension; polymerase chain reaction; potassium channel; pregnancy circulation; pulmonary circulation; sheep; vascular endothelium; vascular resistance; vasodilation; western blottings

DESCRIPTION (provided by applicant): The pulmonary vascular resistance in the fetus undergoes a rapid decrease at birth to facilitate gas exchange during postnatal life. Alteration in this adaptation leads to Persistent Pulmonary Hypertension of Newborn (PPHN), a condition associated with increased morbidity and mortality. The mechanism of this altered adaptation in PPHN remains unknown. Previous studies have shown that pulmonary vasodilation at birth is facilitated by release of ATP from fetal RBC and stimulation of nitric oxide (NO) release from endothelial cells by ATP. Association of Hsp90, a stress protein, with endothelial NOS (eNOS) facilitates release of NO in response to physiological stimuli. Inhibition of Hsp90-NOS interaction appears to uncouple NOS activity from release of NO to superoxide (O2"), a vasoconstrictor. The proposed studies will investigate the hypotheses that (i) association of Hsp90 with eNOS facilitates NO release and vasodilation when normal fetal pulmonary vessels are exposed to ATP, (ii) dissociation of Hsp90 from eNOS during increased pressure load in PPHN shifts the balance of NOS activity from NO to O2- and (iii) O2 impairs No independent vasodilation by inhibition of K channels on vascular smooth muscle. The hypotheses will be investigated in fetal lambs with pulmonary hypertension induced by constriction of ductus arteriosus, an established model of PPHN, and in control lambs with sham ligation of ductus arteriosus. Studies will be done in pulmonary arteries isolated from control and PPHN lambs to determine the role of Hsp90-NOS interaction and Kv channels in normal relaxation response to ATP and the role of uncoupled NOS activity in the impaired response in PPHN Studies in endothelial cells from control and PPHN lambs will determine the effect of ATP on (a) balance of NO and O2- release from eNOS, (b) Hsp90 - eNOS association and (c) serine-1177-phosphorylation of eNOS, a marker of its activation. These studies will (1) delineate the role of Hsp90-eNOS association in stimulation of NO release by ATP and (2) determine if decreased Hsp90-eNOS association results in generation of O2 when NOS is activated by ATP. The proposed studies will also address two potential mechanisms for decreased Hsp90-eNOS association in PPHN: (a) decreased tyrosine phosphorylation of Hsp90 due to nitrotyrosine formation and (b) recruitment of Hsp90 to cytoskeleton proteins, actin and a-tubulin to preserve their integrity during increased pressure load. These studies will provide new information on mechanisms of impaired adaptation in PPHN.

描述（由申请人提供）：胎儿中的肺血管耐药性在出生时会迅速减少，以促进产后生命期间的气体交换。这种适应性的改变会导致新生儿（PPHN）的持续性肺动脉高压，这种疾病与发病率和死亡率的增加有关。这种改变PPHN的适应性的机制仍然未知。先前的研究表明，通过胎儿RBC释放ATP并刺激ATP从内皮细胞从内皮细胞释放一氧化氮（NO），可以促进出生时的肺血管舒张。 Hsp90的缔合性蛋白质与内皮NOS（ENOS）的缔约蛋白（ENOS）有助于响应生理刺激的NO释放。 HSP90-NOS相互作用的抑制似乎使NOS活性从NO释放到超氧化物（O2“），一种血管收缩器。拟议的研究将调查HSP90（I）HSP90与ENOS与正常胎儿释放的胎盘的释放和血管降低的eNOS（i）eNOS促进（I II）的压力（II）的偏移（II）的偏移（II）的偏移（II）dissociation（II）的偏移（II），II）的假设是（II）的变化（II）。 NOS活性从NO到O2和（III）O2在血管平滑肌上抑制K通道无独立的血管舒张。从对照和PPHN羔羊中分离出的动脉，以确定HSP90-NOS相互作用和KV通道在正常放松对ATP的响应中的作用以及未偶联的NOS活性在受损中的PPHN研究中，来自对照和PPHN LAMBS的PPHN研究中的作用将确定AT​​P对ATP的影响（A）ATP对ENS的效果（A）ENS（A）ENS（a）（a）（a）（a）（a）（a）（c）（c）（c）（c）（c）（b）（c）（c）（c）b） ENOS的丝氨酸-1177-磷酸化，其激活的标志。这些研究将（1）描述HSP90-ENOS关联在刺激ATP释放的刺激中的作用，（2）确定Hsp90-Enos关联的降低是否会导致NOS被ATP激活时的O2产生。拟议的研究还将解决PPHN中HSP90-ENOS关联降低的两种潜在机制：（a）由于硝基苯胺的形成而导致HSP90的酪氨酸磷酸化降低，以及（b）将Hsp90募集到HSP90对细胞骨骼蛋白质，肌动蛋白和A-微管蛋白的整合性增加的繁殖。这些研究将提供有关PPHN适应受损机制的新信息。