Redox Regulation of Vascular cGMP Signaling in Neonatal Lungs

新生儿肺血管 cGMP 信号传导的氧化还原调节

• 批准号: 8162629
• 负责人: KATHRYN N FARROW
• 金额: $ 44.47万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-15 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8162629
• 关键词: Affect; Animal Model; Animals; Antioxidants; Blood Vessels; Bronchopulmonary Dysplasia; Case Series; Cell Proliferation; Chemicals; Clinical Research; Complication; Critical Pathways; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Data; Development; Disease; Drug Kinetics; Exposure to; Functional disorder; Future; Growth; Health Care Costs; Heart failure; Hyperoxia; Infant; Knockout Mice; Life; Lung; Measures; Mechanical ventilation; Mediating; Mediator of activation protein; Mitochondria; Mitochondrial Matrix; Molecular; Morbidity - disease rate; Mus; Neonatal; Oxidation-Reduction; Oxidative Stress; Oxygen; Pathway interactions; Phase; Premature Birth; Prevalence; Prevention; Production; Publishing; Pulmonary Hypertension; Pulmonary artery structure; Reactive Oxygen Species; Regulation; Right Ventricular Hypertrophy; Risk; Role; SOD2 gene; Side; Signal Pathway; Signal Transduction; Slice; Smooth Muscle Myocytes; Soluble Guanylate Cyclase; Techniques; Testing; Therapeutic; Time; Vascular remodeling; Wild Type Mouse; improved; inhibitor/antagonist; mortality; mouse model; neonate; new therapeutic target; novel; phosphodiesterase V; pre-clinical; prevent; pup; ratiometric; restoration; sensor; sildenafil

DESCRIPTION (provided by applicant): Bronchopulmonary dysplasia (BPD) is a common complication of preterm birth affecting 30% of infants with birthweights < 1000 grams. Recently, pulmonary hypertension (PH) and right-sided heart failure have been recognized as complications in infants with moderate or severe BPD. While the true prevalence remains unknown, one case series estimates that PH occurs in up to 25% of BPD infants. Once infants develop PH, little is known about how to treat them, and risk of morbidity and mortality is very high. One of the mainstays of BPD therapy is oxygen (O2), but supraphysiologic O2 concentrations in combination with mechanical ventilation increase reactive oxygen species (ROS) production, inducing significant vascular dysfunction in neonates. Potential key targets for ROS-mediated dysregulation in the pulmonary vasculature are soluble guanylate cyclase (sGC) and phosphodiesterase 5 (PDE5). We have previously demonstrated that hyperoxia exposure leads to increased PDE5 expression and activity with concomitant decreased cGMP, and we have preliminary data that hyperoxia exposure decreases sGC expression and activity. Thus, if neonates are born prematurely and exposed to mechanical ventilation with supraphysiologic O2, then both sGC and PDE5 are vulnerable to dysregulation that can impact pulmonary vasoreactivity and vascular remodeling, leading to right ventricular hypertrophy over time. Our group has previously published that hyperoxia exposure increases both mitochondrial and cytoplasmic ROS in isolated pulmonary artery smooth muscle cells (PASMC). Mitochondrially-targeted antioxidants are sufficient to decrease PDE5 activity and restore normal cGMP levels in isolated PASMC. Additionally, in unpublished data, protein kinase G I1 (PKGI1) inhibitors are sufficient to block ROS-mediated increases in PDE5 and restore normal cGMP levels. We hypothesize that preterm birth combined with exposure to hyperoxia-induced mitochondrial ROS disrupts the critical sGC-cGMP-PKG-PDE5 signaling pathway within the lung, leading to abnormal pulmonary vascular growth and RVH as seen in infants with BPD and pulmonary hypertension. We will utilize the established mouse model of BPD in combination with novel techniques including neonatal mouse PASMC, neonatal living lung slices, and ratiometric redox sensors, to elucidate the molecular mechanism by which ROS disrupts this pathway. Furthermore, we will utilize the BPD mouse model to test whether antioxidants or sildenafil, a PDE5 inhibitor, are sufficient to either prevent PH if given concurrently with oxygen exposure or to reverse established PH if given during the convalescent phase. These studies will provide the pathophysiologic, mechanistic framework for future pre-clinical and clinical studies to improve prevention and pharmacologic treatment of BPD infants with PH. PDE5 inhibitors, such as sildenafil, are clinically available, and pharmacokinetic data are available for term neonates. They represent the most immediate therapeutic option for these infants if a rationale for their use can be demonstrated. PUBLIC HEALTH RELEVANCE: Pulmonary hypertension associated with bronchopulmonary dysplasia is a late complication of premature birth that results in significant long-term morbidity, increased health care costs and utilization, and in many cases, increased mortality. In this proposal, we will utilize a mouse model to determine how oxygen exposure negatively impacts soluble guanylate cyclase-cGMP-phosphodiesterase-5 signaling in this condition and whether treatment with antioxidants or sildenafil, a phosphodiesterase-5 inhibitor, can reverse established disease.

描述（由申请人提供）：支气管肺发育不良（BPD）是一种常见的早产并发症，影响30%的出生体重< 1000克的婴儿。最近，肺动脉高压（PH）和右侧心力衰竭已被认为是中度或重度BPD婴儿的并发症。虽然真正的患病率尚不清楚，但一个病例系列估计，PH在高达25%的BPD婴儿中发生。一旦婴儿出现PH，人们对如何治疗知之甚少，发病率和死亡率的风险非常高。BPD治疗的主要支柱之一是氧气（O2），但超生理氧浓度与机械通气相结合会增加活性氧（ROS）的产生，导致新生儿血管功能障碍。ros介导的肺血管失调的潜在关键靶点是可溶性鸟苷酸环化酶（sGC）和磷酸二酯酶5 （PDE5）。我们之前已经证明，高氧暴露导致PDE5表达和活性增加，同时cGMP降低，我们有初步数据表明高氧暴露会降低sGC表达和活性。因此，如果新生儿早产并暴露于机械通气下的超生理氧，那么sGC和PDE5都容易发生失调，从而影响肺血管反应性和血管重塑，导致右心室肥厚。本小组先前发表的研究表明，高氧暴露会增加离体肺动脉平滑肌细胞（PASMC）的线粒体和细胞质ROS。线粒体靶向抗氧化剂足以降低PDE5活性并恢复离体PASMC的正常cGMP水平。此外，在未发表的数据中，蛋白激酶g1 （PKGI1）抑制剂足以阻断ros介导的PDE5升高并恢复正常的cGMP水平。我们假设早产与暴露于高氧诱导的线粒体ROS破坏肺内关键的sGC-cGMP-PKG-PDE5信号通路，导致肺血管生长异常和RVH，如BPD和肺动脉高压婴儿所见。我们将利用建立的小鼠BPD模型，结合新技术，包括新生儿小鼠PASMC，新生儿活肺切片和比例氧化还原传感器，来阐明ROS破坏这一途径的分子机制。此外，我们将利用BPD小鼠模型来测试抗氧化剂或西地那非（一种PDE5抑制剂）是否足以防止PH（如果同时给予氧暴露）或逆转已建立的PH（如果在恢复期给予）。这些研究将为未来的临床前和临床研究提供病理生理学、机制框架，以改善ph - PDE5抑制剂（如西地那非）对BPD婴儿的预防和药物治疗。如果可以证明使用它们的理由，它们代表了这些婴儿最直接的治疗选择。