Department of Chemical and Biochemical Engineering, Faculty of Engineering, The University of Western Ontario, London, Ontario N6A 5B9, Canada.
Biomaterials. 2012 Mar;33(8):2462-72. doi: 10.1016/j.biomaterials.2011.12.001. Epub 2011 Dec 26.
Phenotype regulation of vascular smooth muscle cells (VSMC) is an important requirement in both tissue engineering and balloon angioplasty strategies. In recent years, it has become increasingly evident that the Notch signalling pathway plays a critical role in regulating vascular morphogenesis during development and the transcription of differentiated VSMC and its maturation. In arteries, Notch3 is the predominant receptor on VSMC and, signalling is initiated upon binding to its ligand, Jagged1. However, little is known on how ligand presenting strategies affect Notch signalling and subsequently upregulation of smooth muscle cell differentiation. In this study, using human coronary artery smooth muscle cells (HCASMC) and human coronary artery endothelial cells (HCAEC), we show several lines of evidence that direct heterocellular cell-cell contact is necessary for VSMC differentiation via Notch3 signalling. First, neither the addition of soluble Jagged1 nor Jagged1 immobilized to protein G beads induced HCASMC differentiation in culture. Second, despite the upregulation of Notch3 expression, EC-conditioned medium failed to induce HCASMC differentiation. However, when HCASMC and HCAEC were co-cultured either on opposite sides of porous membrane or when these cells were co-cultured directly, both Notch3 and VSMC differentiation marker proteins were upregulated. These upregulations were abrogated by Jagged1-specific siRNA. This study provides the first direct evidence that contact of HCASMC and HCAEC is required for regulating smooth muscle cell differentiation. These findings may have clinical importance and therapeutic potential for modulating vascular SMC phenotype during various cardiovascular disease states and in tissue engineering.
血管平滑肌细胞（VSMC）的表型调节是组织工程和球囊血管成形术策略的重要要求。近年来，越来越明显的是，Notch 信号通路在发育过程中调节血管形态发生以及分化的 VSMC 的转录及其成熟中起着关键作用。在动脉中，Notch3 是 VSMC 上的主要受体，并且在与配体 Jagged1 结合后启动信号传导。但是，关于配体呈现策略如何影响 Notch 信号传导以及随后上调平滑肌细胞分化的了解甚少。在这项研究中，使用人冠状动脉平滑肌细胞（HCASMC）和人冠状动脉内皮细胞（HCAEC），我们提供了几条证据表明，通过 Notch3 信号传导，直接的异细胞细胞接触对于 VSMC 分化是必需的。首先，添加可溶性 Jagged1 或固定在蛋白 G 珠上的 Jagged1 均不能诱导 HCASMC 在培养物中分化。其次，尽管 Notch3 表达上调，但 EC 条件培养基未能诱导 HCASMC 分化。但是，当 HCASMC 和 HCAEC 在多孔膜的相对侧上共培养时，或者当这些细胞直接共培养时，Notch3 和 VSMC 分化标志物蛋白都被上调。Jagged1 特异性 siRNA 可阻断这些上调。这项研究首次提供了直接证据，表明 HCASMC 和 HCAEC 的接触对于调节平滑肌细胞分化是必需的。这些发现可能对调节各种心血管疾病状态和组织工程中的血管平滑肌细胞表型具有临床意义和治疗潜力。
