Substrate Curvature Regulates Cell Proliferation and YAP Distribution in Spherical Microwells

Bor-Lin Huang^1*, Giovanni J. Paylaga¹, You-Hsuan Liu¹, Cheng-Kuang Huang¹, Keng-Hui Lin¹

¹Institute of Physics, Academia Sinica, Taipei, Taiwan

* Presenter:Bor-Lin Huang, email:borlinhuang@gate.sinica.edu.tw

A growing number of studies show that curvatures at the cellular scale affect cell behaviors but little is known about the curvature sensing mechanism. Our lab pioneered in fabricating spherical microwells and demonstrated that cell proliferation reduced as the microwell radius decreased. In this study, we aim to investigate the distribution of YAP (Yes-Associated Protein), a mechano-responsive transcriptional activator, which regulates cell proliferation. We found that in high-curvature microwells (diameter (d) = 60 µm), YAP was diffusive in cytoplasm and that in low curvature (d = 100 µm), YAP was concentrated in nuclei. We also noticed that cells in 100 µm microwells exert higher traction force and develop pronounced stress fibers compared to those seeded in 60 µm microwells. Myosin perturbation with blebbistatin reduced nuclear flatness, cell conformity to substrate and YAP nuclear shuttling. Based on these findings, we hypothesize that highly curved substrates suppress myosin-mediated contractility, which promotes nuclear compression, YAP translocation, and cell proliferation. We believe our novel spherical microwells can provide insights into the pathway in which the mechanical cues regulate YAP nuclear translocation and associated cell functions.

Keywords: spherical microwell, proliferation, YAP, myosin