Mechanisms of PKG-induced PASMC Differentiation

描述(由申请人提供)：肺损伤导致肺外周动脉中肺血管平滑肌细胞(PASMC)过度增殖和肺高压，并导致婴儿和儿童的显著发病率。实验室研究表明，吸入一氧化氮(NO)可以减轻发育中肺的肺血管疾病。尽管NO的保护机制还不完全清楚，但NO通过刺激可溶性鸟苷环化酶合成cGMP，从而刺激cGMP依赖的蛋白激酶(PKG)来调节PASMC。已经观察到PKG通过抑制细胞增殖、增加收缩蛋白的表达和刺激细胞凋亡来诱导PASMC分化。这项赠款提案的广泛、长期的目标是识别和表征PKG调节PASMC分化的分子机制。最近，我们在酵母双杂交实验中发现了两个新的与PKG相互作用的环指蛋白，TRIM39R和AXOT。由于PKG和环指蛋白都调节细胞分化，它们可能具有相似的信号通路，环指蛋白可能介导了PKG的许多细胞调节活动。该方案的中心假设是，PKG通过与环指蛋白和调节蛋白相互作用来调节PASMC的分化。特定目的1研究TRIM39R如何调节PKG对PASMC增殖、分化和凋亡的调节。特异性目标2定义了PKG和AXOT之间的分子相互作用，并确定了AXOT在调节PKG在PASMC中的重要非血管扩张作用中的作用。特殊目的3利用一种新的实验方法，根据PASMC中它们的差异磷酸化，鉴定新的PASMC中由PKG磷酸化的新的环指和转录调节蛋白。这项拨款申请中提出的研究将为PKG如何调控PASMC的增殖、分化和凋亡提供重要的新机制信息。他们可能提供的信息将导致新的治疗靶点的开发，这些靶点可以用于预防受损肺的肺血管疾病。

DESCRIPTION (provided by applicant): Lung injury causes excessive pulmonary artery smooth muscle cell (PASMC) proliferation in the peripheral arteries of the lung and pulmonary hypertension and significant morbidity in infants and children. Laboratory studies indicate that inhaled nitric oxide (NO) attenuates pulmonary vascular disease in the developing lung. Although the protective mechanisms of NO are incompletely understood, NO regulates PASMC in part by stimulating soluble guanylate cyclase to synthesize cGMP, which stimulates cGMP-dependent protein kinase (PKG). PKG has been observed to induce PASMC differentiation by decreasing cell proliferation, increasing the expression of contractile proteins, and stimulating apoptosis. The BROAD, LONG-TERM OBJECTIVES of this grant proposal are to identify and characterize molecular mechanisms whereby PKG regulates PASMC differentiation. Recently, we identified two novel RING finger proteins, TRIM39R and axotrophin (AXOT), that interact with PKG in a yeast two-hybrid assay. Since PKG and RING finger proteins both regulate cell differentiation, they may share similar signaling pathways and RING finger proteins may mediate many of the cell regulatory activities of PKG. The central hypothesis of the proposal is that PKG regulates PASMC differentiation by interacting with RING finger proteins and regulatory proteins. Specific aim 1 examines how TRIM39R modulates PKG's regulation of PASMC proliferation, differentiation, and apoptosis. Specific aim 2 defines the molecular interaction between PKG and AXOT and defines the role of AXOT in modulating PKG's important non-vasodilatory actions in PASMC. Specific aim 3 utilizes a novel experimental approach to identify new RING finger and transcription regulating proteins phosphorylated by PKG in PASMC, based on their differential phosphorylation in cells. The studies proposed in this grant application will provide important new mechanistic information about how PKG modulates PASMC proliferation, differentiation, and apoptosis. They are likely to provide information that will lead to the development of novel therapeutic targets that can be used to prevent pulmonary vascular disease in the injured lung.