Aβ-RAGE信号通路介导内皮损伤诱导主动脉瓣钙化机制研究

Aortic valve (AV) calcification is a common clinical problem with increased morbidity and mortality. However, the mechanism of AV calcification has not been thoroughly understood. An abundance of evidence have suggested that, AV calcification is not simply a passive degenerative disease, but an active pathological progress akin to atherosclerosis, including endothelial dysfunction , lipoprotein deposition, chronic inflammation, extracellular matrix remodeling, etc. Receptor for advanced glycation end products (RAGE) is a multi-ligand receptor expressed in a range of cell types. The associations among RAGE, inflammation and arterial calcification have been well documented. In our previous study, we showed that RAGE was significantly increased in calcified AVs of hypercholesterolemic rabbits. This implys that RAGE activation may participate in the pathogenesis of AV calcification, and further studies are warranted to elucidate the underlying mechanisms. Endothelial dysfunction is a key event in the intitial states of cariovasucular diseases. We found that Aβ1-42 could induce the apoptosis of valvular endothelial cells (VECs), and co-culture valvular endothelial cells with interstitial cells inhibited the calcification of interstitial cells. We therefore speculate that Aβ-RAGE signaling pathway may promote AV calcification probably by damaging the endothelial barrier. To prove this hypothesis, this study will utilize ApoE and RAGE deficency mice, and primary VECs, to investigate the role and the mechanisms of Aβ-RAGE in AV calcification pathogenesis in both animal and cellular levels, and thus to provide a potential target for AVC prevention and treatment.

RAGE是细胞表面一种多配体受体，广泛参与多种炎症相关性疾病，但在主动脉瓣钙化中的作用机制尚不明确。我们前期工作发现：家兔主动脉瓣钙化模型中RAGE表达显著增多，且激活RAGE可诱导瓣膜间质细胞向成骨样细胞分化，这说明RAGE活化与主动脉瓣钙化密切相关。另外，Aβ在钙化主动脉瓣中显著增多，且Aβ1-42可激活主动脉瓣内皮细胞表面RAGE，诱导内皮细胞凋亡。因而我们推测：Aβ-RAGE通过损伤主动脉瓣内皮功能，加重脂质沉积与巨噬细胞浸润，并诱导瓣膜间质细胞成骨样分化，导致主动脉瓣钙化。本项目拟建立ApoE-/-RAGE-/-小鼠主动脉瓣钙化模型，结合Transwell细胞共培养等方法，观察Aβ-RAGE对主动脉瓣内皮细胞炎症、凋亡、巨噬细胞浸润及亚型变化（M1/M2）以及内皮细胞RAGE活化对瓣膜间质细胞钙化的作用及机制，为阐明主动脉瓣钙化发病机制提供新的实验依据，为临床防治提供潜在靶点。

RAGE是细胞表面一种多配体受体，广泛参与多种炎症相关性疾病，但在主动脉瓣钙化中的作用机制尚不明确。我们前期工作发现：家兔主动脉瓣钙化模型中RAGE表达显著增多，且激活RAGE可诱导瓣膜间质细胞向成骨样细胞分化，这说明RAGE活化与主动脉瓣钙化密切相关。另外，Aβ在钙化主动脉瓣中显著增多，且Aβ1-42可激活主动脉瓣内皮细胞表面RAGE，诱导内皮细胞凋亡。因而我们推测：Aβ-RAGE通过损伤主动脉瓣内皮功能，加重脂质沉积与巨噬细胞浸润，并诱导瓣膜间质细胞成骨样分化，导致主动脉瓣钙化。本项目通过建立ApoE-/-RAGE-/-小鼠主动脉瓣钙化模型，结合Transwell细胞共培养等方法，观察Aβ-RAGE对主动脉瓣内皮细胞炎症、凋亡、巨噬细胞浸润及亚型变化（M1/M2）以及内皮细胞RAGE活化对瓣膜间质细胞钙化的作用及机制，为阐明主动脉瓣钙化发病机制提供了新的实验依据.