Hemodynamic Adaptation of Intercellular Junctions in Human Endothelium

描述(由申请人提供)：血液动力学环境似乎是整个循环中内皮细胞表型的关键调节因素。这与动脉粥样硬化的发展、定位和进展有关。我们正在用一种创新的细胞培养模型来验证这一假设，该模型重建了循环内正常和疾病区域的人体血流动力学剪应力流动模式。这项工作的数据首次表明，不同的剪应力模式调节内皮的表型，包括其炎症状态、动-静脉特性和内皮重构的特征。在动脉粥样硬化的区域，血流作用力(例如，剪切力)与动脉中无疾病的区域明显不同。同样，动脉粥样硬化易感区域的内皮细胞具有炎性表型、更高的周转率和更高的通透性。因此，内皮细胞间连接可能受到损害。有一种范例认为，连接起到了决斗的作用。这些连接不仅在维持通透性屏障方面起着结构性作用，而且通过调节β-和γ-连环蛋白的行为也起到了信号传递的作用。尽管结构作用已经确定，但剪切力对信号作用的影响尚不清楚，可能是导致内皮细胞表型差异的原因之一。我们的总体目标是确定流体剪切力与其对连接稳定性和内皮细胞表型的功能影响之间的机制联系。我们将比较正常和动脉粥样硬化易发区域的血流分布。我们的具体目的是研究切应力对VE-钙粘附素和PECAM与连接素的连接复合体组成变化的影响。我们还将从机械转导、通透性和结构重塑方面研究这种重塑的功能后果。进一步，我们将研究剪切力对连环蛋白的信号、运输和转录活性的影响。一旦完成，这些特定的目标将提高对血液动力学环境的了解，特别是当它与心脏病和中风有关时，并导致这种疾病的新治疗目标。

DESCRIPTION (provided by applicant): The hemodynamic environment appears to be a key regulator of endothelial cell phenotype throughout the circulation. This correlates to the development, localization and progression of atherosclerosis. We are testing this hypothesis with an innovative cell culture model that recreates human hemodynamic shear stress flow patterns from normal and disease regions within the circulation. Data from this work were the first to show that different shear stress patterns modulate the phenotype of the endothelium, including its inflammatory-state, arterial-venous identity, and characteristics of endothelial remodeling. In regions of atherosclerosis, blood flow forces (e.g., shear stress) are distinctly different from regions in arteries free from the disease. Likewise, the endothelium in atherosclerosis-susceptible regions possesses an inflammatory phenotype, higher rate of turnover and increased permeability. Thus, endothelial intercellular junctions might be compromised. There is a paradigm that junctions serve duel functions. The junctions not only serve a structural role in maintaining a permeability barrier, but also a signaling role, by regulating beta- and gamma catenin behavior. Although the structural role is established, the effect of shear stress on the signaling role is less understood and might contribute to differences in endothelial phenotype. Our overall objective is to define a mechanistic link between fluid shear stress and the functional consequences this has on junction stability and endothelial cell phenotype. Flow profiles from normal versus atherosclerosis-prone regions will be compared. Our specific aims are to investigate the effects of shear stress on changes in composition of VE-cadherin and PECAM junction complexes with the catenins. We will also investigate the functional consequences of that remodeling in terms of mechanotransduction, permeability and structural remodeling. Further, we will investigate the effect of shear stress on the signaling, trafficking and transcriptional activity of catenins. Once accomplished, these specific aims will improve understanding of the hemodynamic environment specifically as it relates to heart disease and stroke and lead to new therapeutic targets for this disease.