MMPs/TIMPs系统在息肉状脉络膜血管病变发病中的作用与机制研究

Polypoidal choroidal vasculopathy (PCV) has become a major blinding eye diseases in China. In our last National Natural Science Foundation project, we identified that PCV and intracranial aneurysms share the same genetic predisposition, and indicated that the metabolic abnormalities of vascular extracellular matrix (ECM) is an important factor in the pathogenesis of PCV and intracranial aneurysms. Matrix metalloproteinase/tissue metalloproteinase inhibitors (MMPs/TIMPs) are the main enzymes that regulate ECM degradation and synthesis. Whether they are involved in PCV pathogenesis through the regulation of ECM metabolism is still unclear. Our preliminary experiments showed that the serum MMP-9 and MMP-2 levels and activity were significantly elevated and MMPs/TIMPs imbalanced in PCV patients . Therefore, the imbalance of MMPs/TIMPs system is very likely involved in the PCV pathogenesis. This project will investigate the relationship between MMPs/TIMPs polymorphism and the susceptibility of PCV, to observe the influence of risky mutations on MMPs/TIMPs protein levels and enzyme activity, and simultaneous detect the status of ECM metabolism. For positive MMPs and TIMPs and their variation locus, we will do functional verification by vitro and vivo experiments. To obtain the reliable evidence that MMPs/TIMPs involved in the PCV pathogenesis through the regulation of ECM metabolism.

息肉状脉络膜血管病变(PCV)已成为我国重要的致盲性眼病。我们课题组在上个国家自然基金项目中首次鉴定出PCV与颅内动脉瘤具有一相同的遗传易感性，并提示血管细胞外基质(ECM）的代谢异常是PCV发病的重要因素。基质金属蛋白酶/组织金属蛋白酶抑制剂(MMPs/TIMPs)系统是调节ECM降解与合成的主要酶类，该系统是否通过调控ECM代谢参与PCV发病机制呢？目前尚不清楚。我们的预实验表明PCV患者血清中MMP-9和MMP-2水平及活性显著升高，MMPs/TIMPs失衡。因此MMPs/TIMPs系统的失调极有可能参与了PCV发病。本项目拟探讨MMPs/TIMPs多态性与PCV易感性的关系，分析其危险变异对蛋白水平及酶活性的影响，同时检测ECM代谢状态。对得到的阳性MMPs和TIMPs及其变异位点通过体内外实验进行功能验证，以获得MMPs/TIMPs通过调控ECM代谢参与PCV发病机制的可靠证据。

息肉状脉络膜血管病变(PCV)已成为我国重要的不可逆致盲性眼病。本项目临床观察证实PCV血管网突破Bruch膜侵袭于视网膜色素上皮下。该病理过程涉及细胞外基质（ECM）重塑，基质金属蛋白酶(MMPs)和弹性蛋白酶是调节ECM降解与合成的主要酶类。PCV患者血清MMP9（p<0.001)和MMP2(p=0.001)水平和活性显著升高，但其血清降解产物、房水MMPs水平和血清总的胶原酶活性未受影响。MMP9基因的rs17576, rs3787268和rs2274755三个位点和TIMP3基因的rs9621532和rs5749482两个位点的单核苷酸多态性与PCV发病无关联。PCV患者血清总弹性蛋白酶活性于体外32h和48h时显著升高（p=0.018，p=0.012）。HTRA1本身的弹性蛋白酶活性低下，体外不足以降解Bruch膜弹性纤维层，但与中性粒细胞弹性蛋白酶同时存在时，弹性蛋白酶活性可有成倍升高，并可剥夺α1 抗胰蛋白酶的抗弹性蛋白酶活性，从而大大促进Bruch膜降解。但HTRA1对MMP9的胶原酶活性的促进作用微弱。这些结果表明系统性的ECM代谢失衡参与PCV发病，弹性蛋白酶系统较MMPs系统在该病理过程中有更大作用。