Villard Viviane, Kalyuzhniy Oleksandr, Riccio Orbicia, Potekhin Sergey, Melnik Tatjana N, Kajava Andrey V, Rüegg Curzio, Corradin Giampietro
Institute of Biochemistry, University of Lausanne, CH-1066 Epalinges, Switzerland.
J Pept Sci. 2006 Mar;12(3):206-12. doi: 10.1002/psc.707.
Integrin receptors are the main mediators of cell adhesion to the extracellular matrix. They bind to their ligands by interacting with short amino acid sequences, such as the RGD sequence. Soluble, small RGD-based peptides have been used to block integrin-binding to ligands, thereby interfering with cell adhesion, migration and survival, while substrate-immobilized RGD sequences have been used to enhance cell binding to artificial surfaces. This approach has several important medical applications, e.g. in suppression of tumor angiogenesis or stimulation of bone formation around implants. However, the relatively weak affinity of short RGD-containing peptides often results in incomplete integrin inhibition or ineffective ligation. In this work, we designed and synthesized several new multivalent RGD-containing molecules and tested their ability to inhibit or to promote integrin-dependent cell adhesion when used in solution or immobilized on substrates, respectively. These molecules consist of an oligomeric structure formed by alpha-helical coiled coil peptides fused at their amino-terminal ends with an RGD-containing fragment. When immobilized on a substrate, these peptides specifically promoted integrin alphaVbeta3-dependent cell adhesion, but when used in solution, they blocked alphaVbeta3-dependent cell adhesion to the natural substrates fibronectin and vitronectin. One of the peptides was nearly 10-fold more efficient than fibronectin or vitronectin in promoting cell adhesion, and almost 100-fold more efficient than a linear RGD tripeptide in blocking adhesion. These results indicate that alpha-helical coiled coil peptides carrying an amino-terminal RGD motif can be used as soluble antagonists or surface-immobilized agonists to efficiently inhibit or promote integrin alphaVbeta3-mediated cell adhesion, respectively.
整合素受体是细胞与细胞外基质黏附的主要介质。它们通过与短氨基酸序列（如RGD序列）相互作用来结合其配体。基于RGD的可溶性小肽已被用于阻断整合素与配体的结合，从而干扰细胞黏附、迁移和存活，而固定在底物上的RGD序列则被用于增强细胞与人工表面的结合。这种方法有几个重要的医学应用，例如在抑制肿瘤血管生成或刺激植入物周围的骨形成方面。然而，含短RGD肽的相对较弱亲和力常常导致整合素抑制不完全或连接无效。在这项工作中，我们设计并合成了几种新的多价含RGD分子，并分别测试了它们在溶液中使用或固定在底物上时抑制或促进整合素依赖性细胞黏附的能力。这些分子由α-螺旋卷曲螺旋肽在其氨基末端与含RGD片段融合形成的寡聚结构组成。当固定在底物上时，这些肽特异性地促进整合素αVβ3依赖性细胞黏附，但在溶液中使用时，它们阻断αVβ3依赖性细胞与天然底物纤连蛋白和玻连蛋白的黏附。其中一种肽在促进细胞黏附方面比纤连蛋白或玻连蛋白效率高近10倍，在阻断黏附方面比线性RGD三肽效率高近100倍。这些结果表明，携带氨基末端RGD基序的α-螺旋卷曲螺旋肽可分别用作可溶性拮抗剂或表面固定的激动剂，以有效抑制或促进整合素αVβ3介导的细胞黏附。
