Syndecan Shedding in Vascular Lesion Formation

描述（由申请人提供）： 我们假设氧化脂质以及局部机械应力调节syndecan-1和-4的表达和脱落作为初始适应性反应，最终有助于产生持续的促炎性生长刺激环境，导致血管病变形成。特别是，我们推测，多配体蛋白聚糖脱落在这些促炎刺激将优先结合和有效地隔离相关的血管病变形成的趋化因子和蛋白酶。具体而言，我们计划（1）确定动脉壁力学和氧化脂质作为独立和相互作用因素调节多配体蛋白聚糖表达和脱落的能力。syndecan- 1和-4的表达将采用免疫组织化学和原位杂交技术在高血压ApoE缺陷小鼠中进行表征。此外，将进行相关的体外研究，以确定循环机械应力和氧化脂质的能力，无论是作为孤立的和相互作用的因素，以加强多配体蛋白聚糖的表达和脱落的血管平滑肌细胞和外膜周成纤维细胞。(2)表征由机械应力和氧化脂质激活的信号转导途径，其在调节多配体蛋白聚糖表达和脱落中会聚。氧化还原敏感和不敏感的MAP激酶信号通路在响应机械应力和氧化脂质的收敛调节多配体蛋白聚糖脱落和表达的程度将被确定。此外，独特的途径差异调节syndecan表达和脱落的潜力将被调查和金属蛋白酶作为主要介质的加速syndecan脱落在血管间充质细胞的作用将被定义。(3)定义脱落的多配体蛋白聚糖与选定的致动脉粥样硬化趋化因子和蛋白酶之间的分子结合相互作用。将表征所选趋化因子（RANTES、MCP-1）和蛋白酶（MMP-2、MMP-9）对响应于氧化脂质和/或机械应力而脱落的多配体聚糖相关硫酸乙酰肝素链的相对结合亲和力，并将确定复合蛋白对降解的敏感性。这些数据将有助于随后的研究，旨在评估乙酰肝素和硫酸软骨素的药理学抑制剂的能力，以及syndecan脱落，以限制体外和体内促炎或蛋白水解活性固相梯度的形成。

DESCRIPTION (provided by applicant): We postulate that oxidized lipids, as well as local mechanical stress regulate the expression and shedding of syndecan-1 and -4 as an initial adaptive response that ultimately contributes to the generation of a sustained proinflammatory, growth-stimulating environment that leads to vascular lesion formation. In particular, we speculate that syndecans shed in response to these pro-inflammatory stimuli will preferentially bind and effectively sequester chemokines and proteases relevant to vascular lesion formation. Specifically, we plan to (1) Determine the capacity of arterial wall mechanics and oxidized lipids, both as isolated and interactive factors, to modulate syndecan expression and shedding. The expression of syndecan- 1 and -4 will be characterized in hypertensive ApoE deficient mice using immunohistochemical and in situ hybridization techniques. Moreover, correlative in vitro studies will be performed to determine the capacity of cyclic mechanical stress and oxidized lipids, both as isolated and interactive factors, to potentiate syndecan expression and shedding in vascular smooth muscle cells and periadventitial fibroblasts. (2) Characterize the signal transduction pathways activated by mechanical stress and oxidized lipids that converge in regulating syndecan expression and shedding. The extents to which redox-sensitive and insensitive MAP kinase signaling pathways initiated in response to mechanical stress and oxidized lipids converge in regulating syndecan shedding and expression will be determined. Furthermore, the potential that unique pathways differentially regulate syndecan expression and shedding will be investigated and the role of metalloproteinases as primary mediators of accelerated syndecan shedding in vascular mesenchymal cells will be defined. (3) Define the molecular binding interactions between shed syndecans and selected proatherogenic chemokines and proteases. The relative binding affinities of selected chemokines (RANTES, MCP-1) and proteases (MMP-2, MMP-9) to syndecan associated heparan sulfate chains shed in response to oxidized lipids and/or mechanical stress will be characterized and the susceptibility of the complexed protein to degradation will be defined. This data will facilitate subsequent studies directed at assessing the capacity of pharmacological inhibitors of heparan and chondroitin sulfate, as well as syndecan shedding to limit the formation of pro-inflammatory or proteolytically active solid phase gradients in vitro and in vivo.