LPCAT1 is essential for perinatal lung function and survival

LPCAT1 对于围产期肺功能和生存至关重要

• 批准号: 8286356
• 负责人: JOHN M SHANNON
• 金额: $ 47.98万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8286356
• 关键词: Accounting; Acyltransferase; Adult; Adult Respiratory Distress Syndrome; Affect; Air; Alleles; Alveolar; Attention; Binding; Birth; Breathing; Breeding; Complementary DNA; Complex; Data; Distal; Enzymes; Epithelial Cells; Exons; Family; Fetus; Film; Functional disorder; Gases; Gene Expression; Genes; Histidine; Histopathology; Homeostasis; Host Defense; In Vitro; Inflammation; Knock-out; Knowledge; Lead; Lecithin; Link; Lipids; Liquid substance; Lung; Lung diseases; Mechanics; Mediating; Microarray Analysis; Molecular; Morphology; Mus; Newborn Infant; Palmitates; Pathway interactions; Patients; Perinatal; Phenotype; Phospholipid Transfer Proteins; Phospholipids; Production; Proteins; Pulmonary Surfactant-Associated Protein A; Pulmonary Surfactant-Associated Protein D; Pulmonary Surfactants; Respiratory Failure; Respiratory physiology; Role; Specificity; Structure; Surface; Surface Tension; Tertiary Protein Structure; Testing; Transgenes; Transgenic Mice; Type II Epithelial Receptor Cell; Virus; alveolar lamellar body; alveolar type II cell; deacylation; in vivo; lipid transfer protein; mRNA Expression; mature animal; member; mortality; neonatal death; neonate; postnatal; public health relevance; pulmonary function; research study; respiratory distress syndrome; steroidogenic acute regulatory protein; surfactant; surfactant deficiency; trafficking; treatment strategy

DESCRIPTION (provided by applicant): The air-liquid interface in the lung is a region of high surface tension that, if unmodified, causes alveolar collapse and respiratory failure. Under normal conditions, a surfactant film consisting of saturated phospholipids that is synthesized and secreted by alveolar type II cells reduces this high surface tension. Pulmonary surfactant also contains a family of proteins, SP-A, SP-B, SP-C, and SP-D, which variously contribute to formation of the surfactant film, surfactant homeostasis, and host defense. Pulmonary surfactant deficiency or alteration has been incontrovertibly linked to respiratory distress syndrome (RDS) in neonates and contributes to the lung dysfunction seen in acute respiratory distress syndrome (ARDS) in the mature lung. Phospholipids constitute approximately 85% of the mass of pulmonary surfactant. The single most abundant phospholipid, is saturated phosphatidylcholine (SatPC), particularly dipalmitoylphosphatidylcholine (DPPC). SatPC can be synthesized either de novo or by a mechanism involving the deacylation of monosaturated PC followed by reacylation, usually with palmitate. Studies on surfactant synthesis in vitro have shown that the latter pathway accounts for 55- 75% of the DPPC made by type II cells. Although activity of a lysoPC acyltransferase utilized in reacylation was demonstrated in type II cells over 30 years ago, the corresponding gene has not been heretofore identified. Data accompanying this application demonstrate that we have identified and isolated the mouse cDNA for a lysoPC acyltransferase (LPCAT1) that is highly enriched in type II cells. Using a hypomorphic transgenic mouse, we also demonstrated that decreased LPCAT1 expression reduces SatPC levels in the developing lung and directly correlates with survival. We will extend these studies in three Specific Aims. In the first Specific Aim we will completely inactivate the LPCAT1 gene in the fetus and determine how this affects survival, phospholipid synthesis, and overall gene expression in the lung. In Specific Aim 2 we will generate a conditional knockout of LPCAT1 that will allow us to define the relationship between SatPC pool size and lung function in the adult animal. In Specific Aim 3 we will exploit the role of LPCAT1 in SatPC synthesis to determine its role in the initiation of SatPC transport to lamellar bodies. The completion of these studies will fill important gaps in our knowledge regarding surfactant phospholipid synthesis, and may significantly impact strategies for the treatment of RDS and other lung diseases resulting from an insufficiency in pulmonary surfactant. PUBLIC HEALTH RELEVANCE: Pulmonary surfactant, a complex of lipids and proteins, is absolutely required for making the transition to breathing at birth. A deficit in surfactant is incontrovertibly linked to respiratory distress syndrome (RDS) in newborn infants, and is also associated with acute respiratory distress syndrome (ARDS) in the mature lung. LPCAT1 is an enzyme critical for the production of surfactant lipids. Understanding how LPCAT1 functions in surfactant homeostasis will help develop new strategies for treating RDS in newborns and in patients with lung disease related to inadequate pulmonary surfactant.

描述(申请人提供)：肺内的气液界面是一个表面张力较高的区域，如果不加以修改，会导致肺泡塌陷和呼吸衰竭。在正常情况下，由肺泡II型细胞合成和分泌的由饱和磷脂组成的表面活性物质膜可以降低这种高表面张力。肺表面活性物质还包含一系列蛋白质，SP-A、SP-B、SP-C和SP-D，它们对表面活性物质膜的形成、表面活性物质的动态平衡和宿主防御有不同的贡献。肺表面活性物质缺乏或改变与新生儿呼吸窘迫综合征(RDS)有关，并与成熟肺中的急性呼吸窘迫综合征(ARDS)的肺功能障碍有关。磷脂约占肺表面活性物质质量的85%。最丰富的单一磷脂是饱和磷脂酰胆碱(SatPC)，特别是二棕榈酰磷脂酰胆碱(DPPC)。Sat PC可以从头合成，也可以通过一种机制来合成，该机制涉及到单饱和PC的脱酰化，然后是反应，通常是与棕榈酸酯。体外合成表面活性物质的研究表明，后者占II型细胞产生的DPPC的55%-75%。尽管在30多年前，在II型细胞中已经证明了用于反应的溶酶PC酰基转移酶的活性，但到目前为止，相应的基因还没有被鉴定。伴随这项应用的数据表明，我们已经鉴定和分离了小鼠的溶血磷脂酰基转移酶(LPCAT1)的cDNA，该酶在II型细胞中高度丰富。利用一只亚形转基因小鼠，我们还证明了LPCAT1表达的降低会降低发育中的肺中SatPC的水平，并与生存直接相关。我们将在三个具体目标上扩展这些研究。在第一个特定目标中，我们将完全使胎儿中的LPCAT1基因失活，并确定这如何影响存活、磷脂合成和肺中的整体基因表达。在具体目标2中，我们将产生LPCAT1的条件敲除，这将使我们能够定义成年动物SatPC池大小和肺功能之间的关系。在特定的目标3中，我们将利用LPCAT1在SatPC合成中的作用来确定它在SatPC向板层小体转运的起始过程中的作用。这些研究的完成将填补我们在表面活性物质磷脂合成方面的重要知识空白，并可能显著影响因肺表面活性物质不足而导致的RDS和其他肺部疾病的治疗策略。 与公共健康相关：肺表面活性物质是一种脂质和蛋白质的复合体，在出生时过渡到呼吸是绝对必要的。肺表面活性物质缺乏无疑与新生儿呼吸窘迫综合征(RDS)有关，也与成熟肺的急性呼吸窘迫综合征(ARDS)有关。LPCAT1是一种对产生表面活性物质脂类至关重要的酶。了解LPCAT1如何在表面活性物质动态平衡中发挥作用，将有助于开发治疗新生儿和与肺表面活性物质不足相关的肺部疾病患者的RDS的新策略。