Interventions Against the Molecular Etiology of BMPR2-induced PAH

针对 BMPR2 诱导的 PAH 分子病因学的干预措施

• 批准号: 8286974
• 负责人: JAMES D WEST
• 金额: $ 50.17万
• 依托单位: VANDERBILT UNIVERSITY
• 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/8286974
• 关键词: Adhesions; Agonist; BMPR2 gene; Blood Glucose; Blood Vessels; Cell Culture Techniques; Cell Nucleus; Cells; Chronic; Coculture Techniques; Data; Disease; Etiology; Functional disorder; Genes; Genetic Transcription; Glucocorticoid Receptor; Glucocorticoids; Human; Inflammation; Inflammatory; Intervention; LIMK1 gene; Lead; Left; Libraries; Life; Ligands; Lipid Peroxidation; Lipids; Literature; Lung; Macrophage Activation; Mediating; Metabolism; Mitochondria; Molecular; Mus; Mutant Strains Mice; Mutation; Pathogenesis; Pathologic; Pathway interactions; Permeability; Peroxides; Phenotype; Predisposition; Production; Protein Dephosphorylation; Pulmonary Hypertension; Pulmonary artery structure; Reactive Oxygen Species; Receptor Signaling; Regulation; Signal Transduction; Smooth Muscle Myocytes; Staining method; Stains; Systolic Pressure; Testing; Thrombus; Transgenic Mice; Ventricular; Weight Gain; aerobic glycolysis; arterial remodeling; bone morphogenic protein; cofilin; human data; macrophage; monocyte; mouse model; mutant; mutation carrier; public health relevance; pulmonary arterial hypertension; receptor; research study; vasoconstriction

DESCRIPTION (provided by applicant): Idiopathic pulmonary arterial hypertension (PAH) is a lethal disorder characterized by pulmonary arterial remodeling, increased RVSP, chronic inflammation and vasoconstriction. The familial form of PAH is usually due to mutations in the type 2 receptor for Bone Morphogenic Protein, BMPR2. Examination of the consequences of BMPR2 mutation in transgenic mice and in cell culture, corroborated by human data from the literature, implicates several pathways that converge to promote PAH. Our preliminary data indicate that BMPR2 mutation causes dephosphorylation of cofilin, likely through direct regulation of LIMK. Dephosphorylation of cofilin drives the glucocorticoid receptor (GR) into the nucleus, where in the absence of ligand it causes both abnormal signaling and glucocorticoid insensitivity. This paradoxically causes some GR-dependent agonist effects, thus weight gain and high blood glucose in BMPR2 mutant humans and mice, but causes inability to signal through others, leaving BMPR2 mutation carriers susceptible to the chronic inflammation, which glucocorticoids are meant to suppress. Glucocorticoid activation and elevated blood glucose can lead to elevated reactive oxygen species (ROS) through mitochondrial ROS production. Our data indicate that BMPR2 mutant mice have a ~2x increase in lipid peroxidation in whole lung, increased pulmonary vascular peroxidized lipid staining, and increased expression of ROS-responsive genes. Also, all BMPR2 mutations tested in cultured smooth muscle cells lead to a ~2x increase in peroxide formation, and RNA expression changes suggestive of increased ROS and a shift to aerobic glycolysis and glutaminolysis. Aberrant glucocorticoid receptor signaling leads to increased vascular adhesion and permeability by monocytes, and this in combination with increased ROS may drive recruitment of monocytes and alternative (M2) macrophage activation, which can drive pathologic changes to the pulmonary vasculature in their microenvironment. To synthesize these data, we hypothesize that the important early etiologic changes caused by BMPR2 mutation are aberrant glucocorticoid receptor signaling and increased ROS, which drive increased recruitment of monocytes, alternative (M2) macrophage activation, and remodeling of the pulmonary vasculature. This chronic inflammatory state in precapillary pulmonary arteries leads to PAH through loss of normal vasoreactivity, increased formation of thrombi, and a predisposition to proliferation caused by microenvironmental changes brought about by interactive signaling between BMPR2 mutant vascular cells and macrophages. This study will clarify the early molecular etiology of BMPR2-induced PAH, as well as providing information about BMP regulation of inflammation with implications to a host of diseases. PUBLIC HEALTH RELEVANCE: This project tests the hypothesis that BMPR2 mutation predisposes to pulmonary hypertension by directly causing glucocorticoid receptor dysfunction leading to increased reactive oxygen species and recruitment of circulating cells to the lungs. A combination of cell culture and transgenic mouse model experiments will be used to test this hypothesis.

描述（由申请人提供）：特发性肺动脉高压（PAH）是一种致命性疾病，其特征为肺动脉重塑、RVSP 增加、慢性炎症和血管收缩。家族性 PAH 通常是由于骨形态发生蛋白 BMPR2 的 2 型受体突变所致。对转基因小鼠和细胞培养物中 BMPR2 突变的影响进行了检查，并得到了文献中的人类数据的证实，表明了几种共同促进 PAH 的途径。我们的初步数据表明 BMPR2 突变可能通过直接调节 LIMK 导致 cofilin 去磷酸化。丝切蛋白的去磷酸化驱动糖皮质激素受体 (GR) 进入细胞核，在没有配体的情况下，它会导致异常信号传导和糖皮质激素不敏感。矛盾的是，这会导致一些 GR 依赖性激动剂效应，从而导致 BMPR2 突变人类和小鼠体重增加和高血糖，但导致无法通过其他信号传递信号，使 BMPR2 突变携带者容易受到糖皮质激素旨在抑制的慢性炎症的影响。糖皮质激素激活和血糖升高可通过线粒体 ROS 产生导致活性氧 (ROS) 升高。我们的数据表明，BMPR2 突变小鼠全肺脂质过氧化增加约 2 倍，肺血管过氧化脂质染色增加，ROS 反应基因表达增加。此外，在培养的平滑肌细胞中测试的所有 BMPR2 突变都会导致过氧化物形成增加约 2 倍，并且 RNA 表达变化表明 ROS 增加以及有氧糖酵解和谷氨酰胺分解的转变。异常的糖皮质激素受体信号传导导致单核细胞的血管粘附和通透性增加，这与ROS增加相结合可能会促进单核细胞的募集和替代性（M2）巨噬细胞的激活，从而驱动微环境中肺血管系统的病理变化。为了综合这些数据，我们假设 BMPR2 突变引起的重要早期病因变化是异常的糖皮质激素受体信号传导和 ROS 增加，这导致单核细胞募集增加、替代性 (M2) 巨噬细胞激活和肺血管系统重塑。毛细血管前肺动脉的这种慢性炎症状态通过正常血管反应性丧失、血栓形成增加以及BMPR2突变血管细胞和巨噬细胞之间的相互作用信号传导引起的微环境变化引起的增殖倾向而导致PAH。这项研究将阐明 BMPR2 诱导的 PAH 的早期分子病因学，并提供有关 BMP 对炎症的调节以及对许多疾病的影响的信息。 公共健康相关性：该项目测试了以下假设：BMPR2 突变直接导致糖皮质激素受体功能障碍，导致活性氧增加和循环细胞向肺部募集，从而诱发肺动脉高压。细胞培养和转基因小鼠模型实验的结合将用于检验这一假设。