siPiezo1 or scRNA immortalised MSC cell line (Y201) cultured on soft hydrogels

Mechanosensitive ion channels have emerged as fundamental proteins in sensing extracellular matrix (ECM) mechanics. Among those, Piezo1 has been proposed as a key mechanosensor in cells. However, whether and how Piezo1 senses time-dependent ECM mechanical properties (i.e., viscoelasticity) remains unknown. To address this question, we combined an immortalised mesenchymal stem cell (MSC) line with adjustable Piezo1 expression with soft (0.4 kPa) and stiff (25 kPa) viscoelastic hydrogels with independently tuneable Young's modulus and stress relaxation. Here, we propose that Piezo1 is an important sensor of stiffness at this range (25kPa) consistent with the molecular clutch model. By performing RNA sequencing (RNA-seq), we identified the transcriptomic phenotype of MSCs response to matrix viscoelasticity and Piezo1 activity, highlighting gene signatures that drive MSCs mechanobiology at this elasticity scale. Overall design: RNAseq profiling of small interferring RNA (siPiezo1) and scrambled RNA (scRNA) treated immortalised mesenchymal stem cells (Y201) grown on 0.4 kPa elastic (V-) and viscoelastic (V+) Fibronectin coated polyacrylamide hydrogels. Three independent biological replicates cultured in parallel in a single experiment were sequenced.