BMP9在眼眶静脉畸形发生中的作用及其机制研究

Orbital venous malformation (OVM) is one of common orbital diseases, which can severely cause disfigured appearance as well as impaired visual function. Previous studies consistently demonstrated that the downregulation of bone morphogenetic protein-9 (BMP9) could potentially induce OVM. The evidences are listed as follows: 1. BMP9 level in serum of OVM patients is significantly lower than healthy people. 2. BMP9 can upregulate extracellular matrix and enhance the angiogenesis of endothelial cells (ECs), which is the prerequisite to maintain normal structure of vessels. In order to explore the role of BMP9 in OVM and to clarify its regulatory mechanism, the project intends to carry out investigations in following aspects: firstly, to determine the role of BMP9 in OVM by using animal models. Secondly, to screen the downstream key factors of BMP9 by isobaric tags for relative and absolute quantification (iTRAQ), and evaluate their roles in cell lines as well as animal models. Thirdly, to elucidate the regulatory mechanism exhibited by BMP9 to the key factors by utilizing the techniques of tandem affinity purification (TAP/MS) and co-immunoprecipitation (Co-IP). Finally, to verify the expression of BMP9 and other key factors in the tissues from OVM patients. The findings of our study are promising to provide scientific evidences for new therapeutic targets in the management of OVM.

眼眶静脉畸形（OVM）是常见眼眶疾病，可严重损害患者外观和视力。前期研究表明，骨形态发生蛋白9（BMP9）表达下降，是促进OVM发生的重要因素：1、OVM患者血液中BMP9水平显著低于健康人；2、BMP9可促进血管内皮细胞（ECs）表达细胞外基质蛋白，并增强ECs成管能力（均为维持血管结构的重要条件）。为明确BMP9在OVM发生中的作用及其机制，本项目拟从以下四个方面开展研究：1、利用动物模型，确立BMP9在OVM发生中的作用；2、应用同位素标记定量（iTRAQ）等方法，解析BMP9下游关键因子，并在细胞水平、动物模型层面进行验证；3、采用串联亲和纯化/质谱(TAP/MS)、免疫共沉淀（Co-IP）等技术手段，阐明BMP9调控关键因子的作用机制；4、在OVM临床组织标本中验证BMP9和关键因子的表达及修饰情况。本项目的实施，有望为针对BMP9开展OVM的防治研究提供科学依据。

眼眶静脉畸形（OVM）是常见眼眶疾病，可严重损害患者外观和视力。OVM患者血管壁平滑肌层缺失断裂、结构蛋白α-SMA和DESMIN表达下调是OVM发生的组织学基础之一，找到其上游关键调控因子至关重要。前期结果表明，OVM患者血清中骨形态发生蛋白9（BMP9）水平显著低于健康人。本研究通过构建BMP9敲除小鼠模型、人源化BMP9重组蛋白等手段，首次解释了BMP9缺失促进OVM发展的分子机制：BMP9可抑制脐静脉内皮细胞迁移能力、促进其体外成管活动，从而维持细胞静息状态，并通过激活ALK1-SMAD1/5-ID1信号通路，促进脐静脉平滑肌细胞表达α-SMA等结构蛋白；同时，敲除BMP9的c57小鼠出现血管壁和气管壁α-SMA表达缺失，管腔平滑肌层缺失、断裂。基于上述结果，课题组通过构建体内疾病模型进一步明确，BMP9预处理血管内皮细胞可延缓静脉畸形进展，有望为针对BMP9缺失开展OVM防治提供科学依据。上述研究结果已发表于国际心脏研究协会（International Society for Heart Research）会刊J Mol Cell Cardiol。同时，在研究过程中，课题组利用收集的血管性疾病（VA）家系联合全外显子测序技术，发现导致遗传型VA发生的新型突变基因GPAA1（c.968A > G），相关论文A novel variant in GPAA1, encoding a GPI transamidase complex protein, causes inherited vascular anomalies with various phenotypes发表于遗传学杂志Hum Genet。并利用单细胞转录组测序技术，揭示了OVM与海绵状血管畸形之间的细胞构成及免疫微环境差异，为后续探究奠定基础，相关论文Cellular heterogeneity and immune microenvironment revealed by single-cell transcriptome in venous malformation and cavernous venous malformation发表于J Mol Cell Cardiol。研究期间培养博士三名，硕士两名，受邀参加国内外学术会议做专题报告5次。