Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA.
Proc Natl Acad Sci U S A. 2011 Jul 5;108(27):10986-91. doi: 10.1073/pnas.1101315108. Epub 2011 Jun 20.
RBCs are known to release ATP, which acts as a signaling molecule to cause dilation of blood vessels. A reduction in the release of ATP from RBCs has been linked to diseases such as type II diabetes and cystic fibrosis. Furthermore, reduced deformation of RBCs has been correlated with myocardial infarction and coronary heart disease. Because ATP release has been linked to cell deformation, we undertook a multiscale approach to understand the links between single RBC dynamics, ATP release, and macroscopic viscosity all at physiological shear rates. Our experimental approach included microfluidics, ATP measurements using a bioluminescent reaction, and rheology. Using microfluidics technology with high-speed imaging, we visualize the deformation and dynamics of single cells, which are known to undergo motions such as tumbling, swinging, tanktreading, and deformation. We report that shear thinning is not due to cellular deformation as previously believed, but rather it is due to the tumbling-to-tanktreading transition. In addition, our results indicate that ATP release is constant at shear stresses below a threshold (3 Pa), whereas above the threshold ATP release is increased and accompanied by large cellular deformations. Finally, performing experiments with well-known inhibitors, we show that the Pannexin 1 hemichannel is the main avenue for ATP release both above and below the threshold, whereas, the cystic fibrosis transmembrane conductance regulator only contributes to deformation-dependent ATP release above the stress threshold.
RBC 被认为会释放 ATP，作为一种信号分子来引起血管扩张。RBC 中 ATP 释放的减少与 II 型糖尿病和囊性纤维化等疾病有关。此外，RBC 变形能力的降低与心肌梗死和冠心病有关。由于 ATP 释放与细胞变形有关，我们采用了一种多尺度方法来理解单个 RBC 动力学、ATP 释放和宏观粘度之间的联系，所有这些都在生理剪切率下进行。我们的实验方法包括使用生物发光反应进行微流体、ATP 测量和流变学。我们使用高速成像的微流控技术可视化单个细胞的变形和动力学，这些细胞已知会经历翻滚、摆动、坦克滑行和变形等运动。我们报告说，剪切稀化不是由于以前认为的细胞变形，而是由于翻滚到坦克滑行的转变。此外，我们的结果表明，在剪切应力低于阈值（3 Pa）时，ATP 释放是恒定的，而在阈值以上，ATP 释放增加并伴有大的细胞变形。最后，通过使用众所周知的抑制剂进行实验，我们表明 Pannexin 1 半通道是 ATP 释放的主要途径，无论是在阈值以上还是以下，而囊性纤维化跨膜电导调节剂仅在应力阈值以上对变形依赖性的 ATP 释放有贡献。
