Significance: There is a lack of a general method to noninvasively and remotely manipulate cells with high spatiotemporal precisions. We developed an ultrasound-based mechanogenetics system to achieve this goal. Cells were engineered with the mechanosensor Piezo1 and genetic transducing modules to perceive the mechanical perturbation generated by the ultrasound wave and transduce it into genetic activities. Mechanosensitive and ultrasound-controllable T cells were further engineered to target and eradicate tumor cells with inducible chimeric antigen receptors. This mechanogenetics approach can be extended to remotely control, in principle, any gene activity in live cells for the reprogramming of cellular functions. This method should also provide a general approach to remotely control molecular functions for biological studies and clinical applications, particularly cell-based cancer immunotherapy.

Significance: Mechanical forces, which guide cellular functions, can be sensed and translated into biochemical information at focal adhesions, where cells physically connect to extracellular matrix (ECM) through transmembrane receptor integrins. Our results have identified that different ECM proteins, type 1 collagen (Col I) and fibronectin (FN), can either transmit or shield from mechanical forces when regulating crucial intracellular signaling, focal adhesion kinase (FAK), with their different accessibility to the corresponding integrin receptors. Whereas the integrin α2 binding site in Col I is constitutively accessible, mechanical tension is required to expose the integrin α5 binding motif in FN. This finding should advance our understanding on how cells perceive extracellular mechanical cues through natural surface materials.

Cell migration requires the fine spatiotemporal integration of many proteins that regulate the fundamental processes that drive cell movement. Focal adhesion (FA) dynamics is a continuous process involving coordination between FA and actin cytoskeleton, which is essential for cell migration. We studied the spatiotemporal relationship between the dynamics of focal adhesion kinase (FAK) and paxillin at FAs in the protrusion of living endothelial cells. Concurrent dual-color imaging showed that FAK was assembled at FA first, which was followed by paxillin recruitment to the FA. By tracking and quantifying FAK and paxillin in migrating cells, the normalized FAK/Paxillin fluorescence intensity (FI) ratio is > 1 (≈4 fold) at cell front, ≈1 at cell center, and < 1 at cell rear. The significantly higher FAK FI than paxillin FI at cell front indicates that the assembly of FAK-FAs occurs ahead of paxillin at cell front. To determine the time difference between the assemblies of FAK and paxillin at nascent FAs, FAs containing both FAK and paxillin were quantified by image analysis and time correlation. The results show that FAK assembles at the nascent FAs earlier than paxillin in the protrusions at cell front.