血管生成素样蛋白7用于新生儿支气管肺发育不良防治的应用基础研究

ANGPTL7 (angiopoietin-like 7) is an endogenous protein expressed richly in mesenchymal stem cells, and is one of the novel paracrine cytokines which was identified by via hierarchical clustering. In our previous work, we have found that ANGPTL7 can restore the proliferation of type II alveolar epithelial cells after LPS stimulation and protect alveolar epithelium from apoptosis in BPD (bronchopulmonary dysplasia) rats. High throughput screening showed that ANGPTL7 can activate Wnt/β-CATENIN pathway in alveolar epithelial cells stimulated by LPS。It is known that activation of Wnt/β-CATENIN pathway plays an important role in alleviating apoptosis and reserving normal cell function. Therefore, we hypothesized that ANGPTL7 may protect the alveolar epithelium during the pathogenesis BPD by regulating Wnt/β-CATENIN pathway. .Further study will evaluate the feasibility and possibility of ANGPTL7 for alveolar epithelial damage repair and prevention and treatment of experimental BPD through the LPS-induced alveolar epithelial cells and hyperoxia induced BPD animal models. Addition, we will systematically elucidate the molecular mechanism of how ANGPTL7 regulating Wnt/β-CATENIN signal pathway through Wnt inhibitor and the Pull-down experiment. Furthermore, we will detect the concentration of ANGPTL7 in umbilical cord blood of different gestation age or perinatal complications, and explore the relationship between ANGPTL7 and the occurrence of BPD. These studies could elucidate the effective components of cell therapy from the perspective of translational medicine and may provide a new strategy for the prevention and treatment of BPD.

ANGPTL7是从间充质干细胞旁分泌众多因子中筛选到、丰富表达的内源性蛋白，前期发现，ANGPTL7可减轻LPS所致肺泡上皮细胞损伤，保护BPD大鼠模型肺泡上皮完整性。高通量筛选显示ANGPTL7可激活LPS处理的肺泡上皮细胞Wnt/β-CATENIN信号通路，已知Wnt/β-CATENIN的激活可减轻肺上皮细胞凋亡，促进增殖，提示ANGPTL7可能通过调控Wnt/β-CATENIN信号通路而保护BPD状态下II型肺泡上皮功能。研究拟通过细胞与动物实验，论证ANGPTL7对肺部上皮细胞的损伤修复作用及治疗BPD的可能性；借助Wnt抑制剂和Pull down实验，阐明ANGPTL7通过调控Wnt/β-CATENIN通路保护新生儿BPD肺损伤的分子机制；检测不同孕周/不同围生期并发症脐带血ANGPTL7含量，探索其与BPD发生的关系；从转化医学角度阐明细胞治疗的有效成分，为BPD防治提供新手段

ANGPTL7是从间充质干细胞旁分泌众多因子中筛选到、丰富表达的内源性蛋白，前期发现 ，ANGPTL7可减轻LPS所致肺泡上皮细胞损伤，保护BPD大鼠模型肺泡上皮完整性。高通量筛选显示ANGPTL7可激活LPS处理的肺泡上皮细胞Wnt/β-CATENIN信号通路，已知Wnt/β-CATENIN的激活可减轻肺上皮细胞凋亡，促进增殖，提示ANGPTL7可能通过调控Wnt/β-CATENIN信号通路而保护BPD状态下II型肺泡上皮功能。研究拟通过细胞与动物实验，论证ANGPTL7对肺部上皮细胞的损伤修复作用及治疗BPD的可能性；借助Wnt抑制剂，阐明ANGPTL7通过调控Wnt通路保护新生儿BPD肺损伤的分子机制；检测脐带血ANGPTL7的含量，探索其与BPD发生的关系；结果发现，ANGPTL7能改善LPS所致的A549的凋亡率及活力，加上Wnt抑制剂IWP2后，A549的凋亡减轻。同时，ANGPTL7能减轻LPS所致的小鼠肺炎症性损伤，改善肺部血管的发育，减轻肺部巨噬细胞及炎症因子的浸润以及减轻Wnt通路中Wnt5a、Flt1蛋白的分泌。临床上，通过检测脐带血ANGPTL7水平，我们发现ANGPTL7水平与胎龄呈负相关关系，与婴儿性别，出生体重以及母亲的年龄，妊娠高血压，妊娠糖尿病等无关。脐带血ANGPTL7水平降低是BPD发生的危险因子（BPD组VS 非BPD组，7.54±3.88 VS 9.91±4.43，P=0.007），并且脐带血ANGPTL7水平与炎症因子呈负相关关系，与血管生长因子VEGF呈正相关关系。本研究通过体外细胞水平以及在体动物实验证明了ANGPTL7对II型肺泡上皮细胞炎症损伤具有保护作用，这种保护性作用可能通过Wnt信号通路发挥作用，此外，从临床上我们得知脐带血ANGPTL7水平探讨脐带血 ANGPTL7 的临床生物学属性及其在生理及病理状态下（先兆子痫，糖尿病等）的分泌规律，其脐带血水平与 BPD 发生率有关系。