肺动脉高压新信号通路与干预靶标发现

Pulmonary artery disease (PAH) is a deadly disease characterized by an increased mean pulmonary artery pressure (mPAP) of >25 mmHg and increased pulmonary vascular resistance due to vascular remodeling, leading to right ventricular failure and death. The underlying molecular pathogenic mechanisms are poorly understood. The current treatments are inefficient to improve the survival of patients and reverse the disease. The long-term objective of this project is thus to identify novel genetic determinants and new molecular mechanisms for PAH and to develop new effective treatments. In 2004, we reported in Nature about the identification of a novel angiogenic factor AGGF1. Recently, we have found that AGGF1 plays a critical role in the pathogenesis of PAH. Homozygous AGGF1 knockout mice are embryonic ally lethal, whereas heterozygous AGGF1 knockout mice spontaneously developed PAH with all relevant features of human PAH patients, including a significantly increased mPAP (27.3 mmHg vs. 16.4　mmHg，P=0.007，n=8), higher total pulmonary resistance, increased muscularization, increased medial wall thickness of pulmonary arteries and right ventricular hypertrophy. However, the molecular mechanisms and signal transduction pathways by which AGGF1 haploinsufficiency causes PAH is unknown. In this project, we plan to utilize AGGF1 knockout mice, endothelial cell-specific AGGF1 knockout mice, and vascular smooth muscle cell-specific knockout mice to conclusively demonstrate the critical role of AGGF1 in the pathogenesis of PAH, to define the molecular mechanisms and signal transduction pathways by which AGGF1 knockout causes PAH, to determine the effects of AGGF1 protein therapy on PAH in a hypoxia-induced mouse model, to identify mutations and rare genomic variants associated with PAH and to determine the association between AGGF expression levels and the pathogenesis of PAH. Successful accomplishment of these goals should lead to identification of a new gene causing PAH (AGGF1), identification of novel molecular mechanisms and previously unrecognized signaling pathways for PAH, and establishment of AGGF1 protein therapy as a new treatment strategy for PAH. This study may also lead to more effective screening and early treatment of high-risk individuals and suggest novel molecular targets for treatment, prevention, and drug development for PAH.

肺动脉高压是肺血管功能和结构改变，导致以肺动脉压力和阻力升高为特征的疾病，最终导致右心衰竭甚至死亡。肺动脉高压是一种高度致死性疾病，但具体分子病理机制尚不清楚，尚无有效治疗手段。我们2004年在Nature报道了一个新血管生长因子AGGF1。 最近我们发现AGGF1在肺动脉高压中起关键作用。AGGF1敲除小鼠肺动脉平均压对比野生型小鼠显著升高，并且伴有其它肺动脉高压表征。我们拟利用AGGF1血管内皮细胞和平滑肌细胞条件性敲除小鼠进一步确认AGGF1在肺动脉高压中的关键作用、阐明AGGF1调控肺动脉高压的信号通路、用AGGF1蛋白靶向治疗肺动脉高压小鼠，并在肺动脉高压病人中筛查AGGF1的突变及罕见变异。本项目的成功完成将确立AGGF1基因为一新的肺动脉高压分子决定因子，阐明AGGF1调控肺动脉血管重构、舒张、肺动脉高压新分子机制，确定AGGF1靶向治疗为一种新的有效的肺动脉高压治疗手段。

肺动脉高压（PAH）是一种高度致死性疾病，但当前仍缺乏有效治疗手段。AGGF1是本项目组前期发现的一新的血管生成因子。本项目首次发现AGGF1功能缺失导致PAH。AGGF1+/-杂合敲除小鼠呈现PAH表型。内皮细胞（EC）特异性敲除AGGF1EKO小鼠和平滑肌细胞（SMC）特异性AGGF1SKO敲除小鼠，均呈现明显肺动脉高压表型，证明AGGF1同时通过EC和SMC导致PAH。本研究进一步阐明了AGGF1导致PAH的分子机制。在EC，AGGF1通过结合其表面受体integrin α5β1、激活FAK-Src-AKT、调控EC功能。在SMC，AGGF1结合其受体integrin α7，抑制SMC中TGF-β前体LAP-TGF-β切割，降低活化TGF-β量、抑制TGF-β成熟、调控SMC表型转换、增值与迁移。本研究同时发现AGGF1蛋白能在PAH小鼠中成功治疗PAH，有望成为治疗PAH新技术。最后通过PAH病例-对照遗传关联分析，我们发现AGGF1基因位点2个遗传变异显著增加PAH风险。另外，我们发现miR-191-5p表达量与PAH相关并调控SWI/SNF染色质重塑复合体重要成分之一SMARCD1的表达，而SMARCD1+/-杂合敲除小鼠呈现PAH表型，首次证明SMARCD1及SWI/SNF染色质重塑复合体在PAH发病中起重要作用。更重要的是miR-191-5p抑制剂抑制SMC增殖、迁移，PAH发生，有可能成为治疗PAH新手段。我们也发现SMC中一SUMOylation调控PAH新分子机制。SUMO1在PAH小鼠中表达量升高，诱导Vps34 SUMOylation，导致Beclin-1-Vps34-Atg14L复合物形成，激活自噬，调控SMC表型转化、增殖、迁移。综上所述，本项目通过分子、细胞、小鼠和PAH病人层面系列技术确立AGGF1、miR-191-5p、SMARCD1为新的PAH分子决定因子，发现PAH发生发展新分子病理机制和新生物学通路，而且确定AGGF1和miR-191-5p为治疗PAH新靶标。共发表SCI论文27篇，其中影响因子>10分论文4篇，同期配发评述文章3篇。申请专利1项、培养博士生26名，硕士生5名，博士后1名。