Pressure in lung development and congenital diaphragmatic hernia

肺部发育压力与先天性膈疝

• 批准号: 9311116
• 负责人: Jason Paul Gleghorn
• 金额: $ 36.94万
• 依托单位: UNIVERSITY OF DELAWARE
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9311116
• 关键词: Abdomen; Address; Affect; Animal Model; Animals; Biophysical Process; Biophysics; Calmodulin; Chest; Coculture Techniques; Congenital Abnormality; Congenital diaphragmatic hernia; Data; Development; Devices; Electrophysiology (science); Engineering; Event; Exhibits; Failure; Feedback; Fetal Lung; Fetal Mortality Statistics; Fluids and Secretions; Future; Grant; Growth; Guanine Nucleotide Exchange Factors; Human; Hypoxemia; In Vitro; Ion Channel; KRAS2 gene; Light; Link; Liquid substance; Live Birth; Lung; Mechanics; Mediating; Microfluidics; Modeling; Molecular; Morbidity - disease rate; Morphogenesis; Mus; Muscle Contraction; Muscle function; Mutation; Myosin Light Chain Kinase; Neonatal; Newborn Infant; Operative Surgical Procedures; Organ; Organ Culture Techniques; Pathway interactions; Perinatal mortality demographics; Peristalsis; Pharmacology; Plasmids; Play; Proteins; Pump; Regulation; Replacement Therapy; Respiratory Diaphragm; Respiratory Insufficiency; Risk; Role; Severities; Signal Pathway; Signal Transduction; Small Interfering RNA; Stimulus; Stretching; Structural Congenital Anomalies; Structural defect; Structure of parenchyma of lung; Survival Rate; System; Techniques; Testing; Thoracic cavity structure; Trachea; Transfection; Translating; Work; airway epithelium; base; clinical translation; cost; embryo surgery; fetal; in vitro Model; keratinocyte growth factor; lung basal segment; lung development; lung pressure; malformation; mechanotransduction; medical specialties; mortality; new therapeutic target; novel; perinatal morbidity; pressure; pulmonary hypoplasia; ras Proteins; respiratory smooth muscle; response; stem; success; targeted treatment; therapeutic target; treatment strategy

ABSTRACT Congenital diaphragmatic hernia (CDH) is a devastating structural birth defect, resulting in significant perinatal morbidity and mortality. In CDH, a failure of the diaphragm to completely close allows abdominal organs to move into the thoracic cavity, compressing the developing lung and resulting in often lethal pulmonary hypoplasia. As the high morbidity and mortality of CDH is linked to a structural defect (abdominal organs compressing the lung) with no consistent genetic defect, identifying signaling pathways to target therapeutically is difficult. To date, treatment strategies have focused on surgically occluding the trachea and increasing fluid accumulation in the lung, which has been linked to accelerated lung growth in animal models. However, these strategies have resulted in minimal improvement to neonatal survival rates, especially in light of the risks of any prenatal surgery. A major challenge in successfully translating these findings from animal models is a poor understanding of how mechanical signals, such as the elevated pressure caused by fluid accumulation, are transduced into accelerated lung growth and branching. Several aspects of this mechanotransduction system have identified. Airway smooth muscle (ASM) has been long known to exhibit peristalsis in the lung, and this has been hypothesized to provide an essential dynamic stimulus to induce branching and growth of the airway. In support of this, we have recently shown that airway pressure directly regulates the timing of branching events, and that this depends on ASM function. In this proposal, we focus on the molecular mechanotransduction pathways downstream of lung pressure. Specifically, we hypothesize novel mechanotransduction pathways connecting pressure to three distinct aspects of lung growth. First, we test the role of the mechanosensitive TRPV4 ion channel and myosin light chain kinase in linking airway smooth muscle function. Secondly, we test the role of TRPV4 and K- Ras in mediating the proliferation and branching of the airway epithelium. Third, we test a positive feedback system, where pressure activated expression of FGF7 leads to increased fluid secretion and further pressurization. To test these aims we utilize ex vivo culture of mouse lungs using our novel microfluidic culture device, allowing us to directly control pressures within the developing lung. Further, we will employ pharmacological inhibition and activation of our proposed pathways. To extend and validate our ex vivo findings, we will additionally use siRNA and plasmid transfection with in vitro culture models. By identifying molecular mechanisms that underlie pressure-based lung morphogenesis, this work will provide a framework for future studies to explore mechanotransduction events central to both normal lung development and the dysregulation that occurs in CDH. Further, this work will identify potential therapeutic targets that can be exploited as adjuncts to or replacements for current surgical CDH treatments.

摘要