Hierarchical Development of Motile Polarity in Durotactic Cells Just Crossing an Elasticity Boundary

Abstract

Cellular durotaxis has been extensively studied in the field of mechanobiology. In principle, asymmetric mechanical field of a stiffness gradient generates motile polarity in a cell, which is a driving factor of durotaxis. However, the actual process by which the motile polarity in durotaxis develops is still unclear. In this study, to clarify the details of the kinetics of the development of durotactic polarity, we investigated the dynamics of both cell-shaping and the microscopic turnover of focal adhesions (FAs) for Venus-paxillin-expressing fibroblasts just crossing an elasticity boundary prepared on microelastically patterned gels. The Fourier mode analysis of cell-shaping based on a persistent random deformation model revealed that motile polarity at a cellbody scale was established within the first few hours after the leading edges of a moving cell passed through the boundary from the soft to the stiff regions. A fluorescence recovery after photobleaching (FRAP) analysis showed that the mobile fractions of paxillin at FAs in the anterior part of the cells exhibited an asymmetric increase within several tens of minutes after cells entered the stiff region. The results demonstrated that motile polarity in durotactic cells is established through the hierarchical step-wise development of different types of asymmetricity in the kinetics of FAs activity and cell-shaping with a several-hour time lag.

Mechanical guidance of self-condensation patterns of differentiating progeny

“…Mesenchymal condensates on a locally stiffened region showed two-step condensation dynamics ( Figure S3 A), which were also observed in the case of iPSC-based liver buds on a uniform Matrigel ( Takebe et al., 2015 ). Primary condensation speed ( v ) was estimated to v ∼ 37 μm/h, which is comparable to the migration speed of mesenchymal fibroblast cells ( Kuboki et al., 2019 ; Moriyama and Kidoaki, 2018 ). Here, the mechanical gradient ( IG = 0.008 ka/μm) is comparable to the previously reported mechanical gradient to drive the directed motion of single smooth muscle cells ( Choi et al., 2012 ; Whang and Kim, 2016 ; Wong et al., 2003 ; Zaari et al., 2004 ).…”

High Axial and Lateral Resolutions on Self-Assembled Gold Nanoparticle Metasurfaces for Live-Cell Imaging

“…20 s for Venus-paxillin provides a diffusion constant of ca. 2.5 × 10 –3 μm 2 /s in a 1.5 μm radius of an exemplary FA according to the Soumpasis equation, , which means that the typical diffusion radius of paxillin per 1 s is ca. 30 nm.…”

Interplay among cell migration, shaping, and traction force on a matrix with cell-scale stiffness heterogeneity

“…For polarized cells on a homogeneous substrate [63,64] and adhesive islands [65], the sequential regulation of focal adhesion, cell shape, and migration has been reported, and the development of the focal adhesion orientation precedes the elongation of the cell body in a few hours [63]. As for cell polarization during durotaxis, the micro-elastically patterned gels can be a platform to investigate the sequential development of cell To elucidate the detailed relationship between cell asymmetry and durotaxis, the time evolution of the asymmetric shape of durotactic fibroblasts was studied on gels with a single stiffness jump [66] (Fig. 3 (a)).…”

“…These results indicate that cell elongation and triangular deformation (extension of the lamellipodia) were enhanced in response to the stiffness gradient, and the magnitude of shape asymmetry grew on a scale of hours. To reveal the sequential order of the responses of focal adhesions and cell shape to the stiffness gradient, the time evolution of focal adhesions in the anterior part of durotactic cells was investigated using fluorescence recovery after photobleaching (FRAP) [66]. The mobile fraction of paxillin and the half-time of fluorescence recovery were measured through live-cell imaging and FRAP analysis of Venus-paxillin in focal adhesions.…”

“…To elucidate the detailed relationship between cell asymmetry and durotaxis, the time evolution of the asymmetric shape of durotactic fibroblasts was studied on gels with a single stiffness jump [ 66 ] ( Fig. 3 (a)).…”