埃默里大学Khalid Salaita研究小组取得一项新突破。他们的研究开发出了活细胞超分辨PAINT技术用于成像皮牛（pN）级别细胞牵引力量。 这一研究成果发表在2020年9月14日出版的《自然—方法学》上。

该研究团队通过整合分子张力探针和DNA点积累在纳米尺度的地形(DNA-PAINT)成像技术开发了tPAINT，用于映射~25-nm分辨率下皮牛级别机械力。为实现活细胞动态张力成像，课题组设计了可逆探针，该探针有一个神秘的对接位点，只有在探针受到作用力超过机械阈值(~ 7-21 pN)时才会出现。

此外，课题组报告了第二种不可逆tPAINT探针，其对接位点永久暴露，可以整合力随时间的历史变化，从而提供通过时间动力学信息换取更高空间分辨率的可能。研究团队应用这两种类型的tPAINT探针，在活的人类血小板和老鼠胚胎成纤维细胞中映射整合素受体所受机械力。重要的是，tPAINT揭示了细胞前沿的血小板受力与Arp2/3复合物核化的动态肌动蛋白环之间的关联。

据介绍，尽管机械力在生物学中起着至关重要的作用，但在亚100 nm分辨率尺度成像细胞力仍然是一个挑战。

附：英文原文

Title: Live-cell super-resolved PAINT imaging of piconewton cellular traction forces

Author: Joshua M. Brockman, Hanquan Su, Aaron T. Blanchard, Yuxin Duan, Travis Meyer, M. Edward Quach, Roxanne Glazier, Alisina Bazrafshan, Rachel L. Bender, Anna V. Kellner, Hiroaki Ogasawara, Rong Ma, Florian Schueder, Brian G. Petrich, Ralf Jungmann, Renhao Li, Alexa L. Mattheyses, Yonggang Ke, Khalid Salaita

Issue&Volume: 2020-09-14

Abstract: Despite the vital role of mechanical forces in biology, it still remains a challenge to image cellular force with sub-100-nm resolution. Here, we present tension points accumulation for imaging in nanoscale topography (tPAINT), integrating molecular tension probes with the DNA points accumulation for imaging in nanoscale topography (DNA-PAINT) technique to map piconewton mechanical events with ~25-nm resolution. To perform live-cell dynamic tension imaging, we engineered reversible probes with a cryptic docking site revealed only when the probe experiences forces exceeding a defined mechanical threshold (~7–21pN). Additionally, we report a second type of irreversible tPAINT probe that exposes its cryptic docking site permanently and thus integrates force history over time, offering improved spatial resolution in exchange for temporal dynamics. We applied both types of tPAINT probes to map integrin receptor forces in live human platelets and mouse embryonic fibroblasts. Importantly, tPAINT revealed a link between platelet forces at the leading edge of cells and the dynamic actin-rich ring nucleated by the Arp2/3 complex.

DOI: 10.1038/s41592-020-0929-2

Source: https://www.nature.com/articles/s41592-020-0929-2