Pulmonary Blood Flow in Lung Development and Congenital Diaphragmatic Hernia

描述(申请人提供)：这是一份K08职业发展奖的申请书，研究胚胎肺血流在正常肺发育中的作用以及先天性横隔疝(CDH)所见的肺异常的发展。先天性心脏病是一种出生缺陷，大约每2500名活产婴儿中就有一名发生。在CDH中，在胎儿发育过程中，横隔膜存在缺陷，导致腹部脏器滞留在胸腔内。CDH与不同程度的肺发育不良、气道分支减少和肺血管的特殊发育缺陷有关，包括肺内动脉肌化增加。继发于潜在的肺血管异常的肺动脉高压，加上肺发育不良，通常会导致CDH新生儿严重的呼吸窘迫，导致高达40%的婴儿死亡率。此外，相当大比例的CDH幸存者患有显著的长期发病率。胚胎肺血流在调节气道分支、形态发生和肺血管发育中的潜在作用尚未被研究。另外，CDH肺发育不良和肺血管异常发生的分子机制尚不完全清楚。这一建议的压倒一切的假设是，正常的肺气道和血管发育具体依赖于足够的胚胎肺血流，胚胎肺血流的不足导致CDH的肺发育缺陷。为了解决这一假说，我们将采用一种新的技术--超声引导下利用CDH小鼠模型进行宫内胎鼠心内注射，以达到以下特定目的：1)证实发育中肺的气道分支形态发生对胚胎肺血流的依赖；2)确定肺壁成熟是否依赖于成熟血管内的胚胎肺血流；以及3)测量CDH中胚胎肺血流不足的模式，并确定CDH肺发育中的气道分支形态发生和血管成熟缺陷是否与胚胎肺血流不足有关。在野生型小鼠和CDH小鼠模型中，将研究与胚胎早期肺血流和组织氧合有关的呼吸道分支、形态发生和肺动脉壁成熟。候选人是一名儿科外科医生，自从成为全职教师以来，他一直与导师密切合作。应聘者受益于一位久负盛名的成功导师，以及非常支持的研究和实践环境。此外，候选人将定期与该机构内一个由肺发育和肺血管生物学专家组成的科学咨询委员会举行会议。应聘者的近期目标是在高级实验发育生物学概念和技术方面获得更多的知识和熟练程度，并能够设计和进行越来越复杂的实验来解决假设驱动的问题。候选人的长期目标是成为一名富有成效的独立研究员，能够为发育生物学和儿科外科领域做出重大贡献，并最终将基础科学成果转化回临床领域。为了实现这些目标，制定了一项系统的职业发展计划，其中包括：在奖励期间获得更多的先进实验技术的经验；课程作业；参加会议、专题讨论会和全国会议；经常与导师会面以获得指导；以及在奖励期间逐步提高独立性。 公共卫生相关性：CDH与婴儿死亡率和长期存活者发病率显著相关。更好地了解CDH肺缺陷的发育机制可能会导致CDH更有效的治疗选择，包括产前和出生后的定向治疗，指向涉及呼吸道分支和肺血管功能的特定机制。此外，更好地了解早期胚胎肺血流在正常肺发育中的作用可能会导致对其他肺发育缺陷的更多了解。

DESCRIPTION (provided by applicant): This is an application for a K08 Career Development Award studying the role of embryonic pulmonary blood flow in normal lung development and the development of lung abnormalities seen in congenital diaphragmatic hernia (CDH). CDH is a birth defect occurring in approximately 1 out of 2,500 live-born infants. In CDH, there is a defect in the diaphragm allowing persistence of abdominal viscera in the chest cavity during fetal development. CDH is associated with varying degrees of lung hypoplasia, with decreased airway branching, and specific developmental defects of the pulmonary vasculature, including increased muscularization of intrapulmonary arteries. The combination of pulmonary hypertension, secondary to the underlying abnormal pulmonary vasculature, along with pulmonary hypoplasia results in often severe respiratory distress in neonates with CDH resulting in high infant mortality of up to 40%. Furthermore, a significant proportion of CDH survivors suffer from significant long-term morbidity. The potential role of embryonic pulmonary blood flow in modulating airway branching morphogenesis and pulmonary vascular development has not been examined. Also, the molecular mechanisms responsible for the development of pulmonary hypoplasia and pulmonary vascular abnormalities in CDH are incompletely understood. The overriding hypothesis for this proposal is that normal lung airway and vascular development is specifically dependent upon adequate embryonic pulmonary blood flow and that deficiencies in embryonic pulmonary blood flow contribute to lung developmental defects in CDH. To address this hypothesis, a novel technique of ultrasound-guided in utero embryonic mouse intracardiac injection utilizing a well-described murine model of CDH will be employed to pursue the following specific aims: 1) to demonstrate the dependence of airway branching morphogenesis on embryonic pulmonary blood flow in the developing lung; 2) to determine whether pulmonary arterial wall maturation is dependent upon embryonic pulmonary blood flow within the maturing vessel; and 3) to measure patterns of deficient embryonic pulmonary blood flow in CDH and determine whether defects in airway branching morphogenesis and vessel maturation in developing CDH lung are related to deficient embryonic pulmonary blood flow. Airway branching morphogenesis and pulmonary arterial wall maturation will be examined in relation to early embryonic pulmonary blood flow and tissue oxygenation in wide-type mice and in a murine model of CDH. The candidate is a pediatric surgeon who has been working closely with the mentor since becoming full-time faculty. The candidate benefits from a well-established and successful mentor and a very supportive research and practice environment. In addition, the candidate will have regular meetings with a scientific advisory committee compromised of experts in lung development and pulmonary vascular biology within the institution. The candidate's immediate goals are to obtain increased knowledge and proficiency in advanced experimental developmental biology concepts and techniques and to be able to design and conduct increasingly sophisticated experiments to address hypothesis-driven questions. The candidate's long-term goals are to become a productive independent investigator who is able to contribute significantly to the fields of developmental biology and pediatric surgery and eventually translate basic science findings back to the clinical realm. To achieve these goals a structured career development plan over the award period has been developed consisting of: gaining increased experience with advanced experimental techniques; course work; participation in conferences, symposia, and national meetings; frequent meetings with the mentor for guidance; and a gradual increase in independence over the award period. PUBLIC HEALTH RELEVANCE: CDH is associated with significant infant mortality and morbidity in long-term survivors. A greater understanding of the developmental mechanisms responsible for the lung defects in CDH could lead to more effective treatment options for CDH involving directed therapies, both prenatal and postnatal, toward specific mechanisms involved in airway branching and pulmonary vascular function. Also, a greater understanding of the role of early embryonic pulmonary blood flow on normal lung development may lead to a greater understanding of other lung developmental defects.