Vega L Johana C M, Lee Min Kyung, Jeong Jae Hyun, Smith Cartney E, Lee Kwan Young, Chung Hee Jung, Leckband Deborah E, Kong Hyunjoon
Neuroscience Program, §Department of Chemical and Biomolecular Engineering, ⊥Department of Molecular and Integrative Physiology, #Department of Chemistry, and &Institute for Genomic Biology, University of Illinois at Urbana-Champaign , Urbana, Illinois, United States.
Biomacromolecules. 2014 Jun 9;15(6):2172-9. doi: 10.1021/bm500335w. Epub 2014 May 15.
Intercellular adhesion modulated by cadherin molecules plays an important role in diverse cellular functions including tissue morphogenesis, regeneration, and pathogenesis. However, it is a challenging task to decipher the effects of cell-cell adhesion in vitro because of difficulty in controlling the extent and numbers of cell-cell contacts. In this study, we hypothesize that tethering recombinant extracellular domains of neural cadherin with a C-terminal immunoglobulin Fc domain (N-Cad-Fc) to a substrate with an immobilized anti-Fc antibody (Fc-antibody) and a bifunctional polymer, which is reactive to both protein and substrate, would allow us to recapitulate cell-cell adhesion, independent of the number of cells plated on the substrate. To examine this hypothesis, we first immobilized Fc-antibody to a polyacrylamide hydrogel and a methacrylate-substituted glass using poly(amino-2-hydroxyethyl-co-2-methacryloxyethyl aspartamide)-g-poly(ethylene glycol)-N-hydroxysuccinimide ester (PHMAA-g-PEGNHS) and then incubated the gel in medium containing defined concentrations of the recombinant N-Cad-Fc. The resulting N-Cad-conjugated substrate enabled us to modulate adhesion of bone marrow stromal cells to the gel surface by varying the surface density of N-Cad-Fc. In contrast, direct chemical conjugation of N-Cad-Fc to the gel surface did not support cell adhesion. Additionally, the glass substrate biologically tethered with N-Cad-Fc promoted neuronal adhesion significantly more than substrates coated with poly-l-lysine. We suggest that this novel biological tethering method could be broadly applicable for modifying substrates with a variety of classical cadherins to enable the systematic study of the effects of cadherin-modulated cell-cell adhesion on cellular activities.
由钙黏蛋白分子调节的细胞间黏附在多种细胞功能中发挥着重要作用,包括组织形态发生、再生和发病机制。然而,由于难以控制细胞间接触的程度和数量,在体外解读细胞间黏附的影响是一项具有挑战性的任务。在本研究中,我们假设将神经钙黏蛋白的重组细胞外结构域与C末端免疫球蛋白Fc结构域(N-Cad-Fc)通过固定化抗Fc抗体(Fc-抗体)和对蛋白质和底物均有反应性的双功能聚合物连接到底物上,将使我们能够重现细胞间黏附,而与接种在底物上的细胞数量无关。为了验证这一假设,我们首先使用聚(氨基-2-羟乙基-co-2-甲基丙烯酰氧基乙基天冬酰胺)-g-聚(乙二醇)-N-羟基琥珀酰亚胺酯(PHMAA-g-PEGNHS)将Fc-抗体固定到聚丙烯酰胺水凝胶和甲基丙烯酸酯取代的玻璃上,然后将凝胶在含有特定浓度重组N-Cad-Fc的培养基中孵育。所得的N-Cad偶联底物使我们能够通过改变N-Cad-Fc的表面密度来调节骨髓基质细胞与凝胶表面的黏附。相比之下,N-Cad-Fc与凝胶表面的直接化学偶联不支持细胞黏附。此外,用N-Cad-Fc生物连接的玻璃底物比涂有聚-L-赖氨酸的底物更能显著促进神经元黏附。我们认为,这种新型的生物连接方法可广泛应用于用各种经典钙黏蛋白修饰底物,以系统研究钙黏蛋白调节的细胞间黏附对细胞活性的影响。