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: 8279185
• 负责人: KATHRYN N FARROW
• 金额: $ 41.02万
• 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/8279185
• 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.

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）和右心衰竭已被认为是中度或重度 BPD 婴儿的并发症。虽然真正的患病率仍不清楚，但一项病例系列估计，高达 25% 的 BPD 婴儿患有 PH。一旦婴儿出现PH，人们对如何治疗知之甚少，并且发病和死亡的风险非常高。 BPD 治疗的支柱之一是氧气 (O2)，但超生理的 O2 浓度与机械通气相结合会增加活性氧 (ROS) 的产生，从而导致新生儿出现严重的血管功能障碍。 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，高氧暴露会导致 PDE5 表达和活性增加，同时 cGMP 降低，并且我们有初步数据表明高氧暴露会降低 sGC 表达和活性。因此，如果新生儿早产并接受超生理性 O2 机械通气，那么 sGC 和 PDE5 都容易出现失调，从而影响肺血管反应性和血管重塑，随着时间的推移导致右心室肥厚。我们的小组之前发表过，高氧暴露会增加离体肺动脉平滑肌细胞 (PASMC) 中的线粒体和细胞质 ROS。线粒体靶向抗氧化剂足以降低 PDE5 活性并恢复分离的 PASMC 中的正常 cGMP 水平。此外，在未发表的数据中，蛋白激酶 G I1 (PKGI1) 抑制剂足以阻断 ROS 介导的 PDE5 增加并恢复正常的 cGMP 水平。我们假设早产加上暴露于高氧诱导的线粒体 ROS 会破坏肺内关键的 sGC-cGMP-PKG-PDE5 信号通路，导致肺血管生长异常和 RVH，如 BPD 和肺动脉高压婴儿中所见。我们将利用已建立的 BPD 小鼠模型，结合新生小鼠 PASMC、新生儿活体肺切片和比例氧化还原传感器等新技术，阐明 ROS 破坏该通路的分子机制。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）是否足以预防 PH（如果与氧气暴露同时给予）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，以改善患有 PH 的 BPD 婴儿的预防和药物治疗。 PDE5 抑制剂，例如西地那非，已在临床上可用，并且可获得足月新生儿的药代动力学数据。如果能够证明其使用的理由，那么它们代表了这些婴儿最直接的治疗选择。