Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems , and Institute of Physical Chemistry, Heidelberg University , Heisenbergstraße 3, Stuttgart 70569, Germany.
ACS Nano. 2013 Nov 26;7(11):9984-96. doi: 10.1021/nn403923h. Epub 2013 Oct 4.
Neutrophilic granulocytes play a fundamental role in cardiovascular disease. They interact with platelet aggregates via the integrin Mac-1 and the platelet receptor glycoprotein Ibα (GPIbα). In vivo, GPIbα presentation is highly variable under different physiological and pathophysiological conditions. Here, we quantitatively determined the conditions for neutrophil adhesion in a biomimetic in vitro system, which allowed precise adjustment of the spacings between human GPIbα presented on the nanoscale from 60 to 200 nm. Unlike most conventional nanopatterning approaches, this method provided control over the local receptor density (spacing) rather than just the global receptor density. Under physiological flow conditions, neutrophils required a minimum spacing of GPIbα molecules to successfully adhere. In contrast, under low-flow conditions, neutrophils adhered on all tested spacings with subtle but nonlinear differences in cell response, including spreading area, spreading kinetics, adhesion maturation, and mobility. Surprisingly, Mac-1-dependent neutrophil adhesion was very robust to GPIbα density variations up to 1 order of magnitude. This complex response map indicates that neutrophil adhesion under flow and adhesion maturation are differentially regulated by GPIbα density. Our study reveals how Mac-1/GPIbα interactions govern cell adhesion and how neutrophils process the number of available surface receptors on the nanoscale. In the future, such in vitro studies can be useful to determine optimum therapeutic ranges for targeting this interaction.
中性粒细胞在心血管疾病中起着至关重要的作用。它们通过整合素 Mac-1 和血小板受体糖蛋白 Ibα（GPIbα）与血小板聚集物相互作用。在体内，GPIbα 的呈现受不同生理和病理生理条件的高度影响。在这里，我们在仿生体外系统中定量确定了中性粒细胞黏附的条件，该系统允许精确调节纳米尺度上呈现的人 GPIbα 之间的间隔从 60nm 到 200nm。与大多数传统的纳米图案化方法不同，这种方法可以控制局部受体密度（间隔），而不仅仅是全局受体密度。在生理流动条件下，中性粒细胞需要 GPIbα 分子的最小间隔才能成功黏附。相比之下，在低流速条件下，中性粒细胞在所有测试的间隔上都黏附，细胞反应略有但非线性差异，包括扩展面积、扩展动力学、黏附成熟和迁移性。令人惊讶的是，Mac-1 依赖性中性粒细胞黏附对 GPIbα 密度变化非常稳健，可达 1 个数量级。这种复杂的反应图谱表明，流动下的中性粒细胞黏附和黏附成熟受到 GPIbα 密度的差异调节。我们的研究揭示了 Mac-1/GPIbα 相互作用如何控制细胞黏附，以及中性粒细胞如何在纳米尺度上处理可用表面受体的数量。在未来，这种体外研究可以有助于确定靶向这种相互作用的最佳治疗范围。
