Boontheekul Tanyarut, Kong Hyun-Joon, Hsiong Susan X, Huang Yen-Chen, Mahadevan L, Vandenburgh Herman, Mooney David J
Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
Faraday Discuss. 2008;139:53-70; discussion 105-28, 419-20. doi: 10.1039/b719928g.
Many functions of the extracellular matrix can be mimicked by small peptide fragments (e.g., arginine-glycine-aspartic acid (RGD) sequence) of the entire molecule, but the presentation of the peptides is critical to their effects on cells. It is likely that some effects of peptide presentation from biomaterials simply relate to the number of bonds formed between cell receptors and the adhesion ligands, but a lack of tools to quantify bond number limits direct investigation of this assumption. The impact of different ligand presentations (density, affinity, and nanoscale distribution) on the proliferation of C2C12 and human primary myoblasts was first examined in this study. Increasing the ligand density or binding affinity led to a similar enhancement in proliferation of C2C12 cells and human primary myoblasts. The nanoscale distribution of clustered RGD ligands also influenced C2C12 cells and human primary myoblast proliferation, but in an opposing manner. A theological technique and a FRET technique were then utilized to quantify the number of receptor-ligand interactions as a function of peptide presentation. Higher numbers of bonds were formed when the RGD density and affinity were increased, as measured with both techniques, and bond number correlated with cell growth rates. However, the influence of the nanoscale peptide distribution did not appear to be solely a function of bond number. Altogether, these findings provide significant insight to the role of peptide presentation in the regulation of cell proliferation, and the approaches developed in this work may have significant utility in probing how adhesion regulates a variety of other cellular functions and aid in developing design criterion for cell-interactive materials.
细胞外基质的许多功能可以通过整个分子的小肽片段（例如，精氨酸-甘氨酸-天冬氨酸（RGD）序列）来模拟，但肽的呈现方式对其对细胞的影响至关重要。生物材料中肽的呈现所产生的一些影响可能仅仅与细胞受体和粘附配体之间形成的键的数量有关，但缺乏量化键数量的工具限制了对这一假设的直接研究。本研究首先考察了不同配体呈现方式（密度、亲和力和纳米级分布）对C2C12细胞和人原代成肌细胞增殖的影响。增加配体密度或结合亲和力会导致C2C12细胞和人原代成肌细胞的增殖有类似的增强。聚集的RGD配体的纳米级分布也影响C2C12细胞和人原代成肌细胞的增殖，但方式相反。然后利用一种流变学技术和一种荧光共振能量转移技术来量化受体-配体相互作用的数量，作为肽呈现方式的函数。用这两种技术测量发现，当RGD密度和亲和力增加时，会形成更多的键，并且键的数量与细胞生长速率相关。然而，纳米级肽分布的影响似乎不仅仅是键数量的函数。总之，这些发现为肽呈现方式在细胞增殖调节中的作用提供了重要的见解，并且本研究中开发的方法在探究粘附如何调节多种其他细胞功能以及协助制定细胞相互作用材料的设计标准方面可能具有重要用途。
