Piezo1 regulates remodeling of skin-derived extracellular matrix by embedded umbilical cord mesenchymal stem cells in a stiffness-dependent fashion.

Cells continuously sense and adapt to the mechanical properties of their surrounding extracellular matrix (ECM), yet how human umbilical cord-derived mesenchymal stromal cells (UC-MSCs) mechanotransduce stiffness cues in 3D ECM remains incompletely understood. This knowledge gap limits the rational design of MSC-based regenerative therapies and mechanically instructive biomaterials. Here, using ruthenium-catalyzed photocrosslinked skin-derived ECM hydrogels spanning a physiological to fibrotic stiffness range, we demonstrate that UC-MSCs exhibit distinct, stiffness-dependent remodeling strategies. Soft matrices (1.2 kPa) induced cell-mediated hydrogel contraction, medium stiffness (3.4 kPa, comparable to native skin) supported elongated cell morphology with minimal remodeling, whereas stiff matrices (17.7 kPa) kept seeded UC-MSCs rounded and induced pericellular void formation consistent with localized ECM remodeling. By decoupling geometric contraction from intrinsic ECM turnover using volume-normalized mechanical analyses, we identify the Piezo1 as a key regulator of stiffness-dependent adaptation. Piezo1 expression increased with stiffness, and its inhibition attenuated contraction in soft matrices and prevented stiffness reduction in stiff matrices, indicating that Piezo1 enables MSCs to mechanically adapt across 3D microenvironments. Analysis of matrix metalloproteinase expression revealed stiffness-dependent regulation of MMP2 and MMP14; however, their expression was only marginally affected by Piezo1 inhibition, suggesting that Piezo1 influences ECM remodeling through mechanisms beyond direct regulation of MMP expression. Together, these findings establish a mechanistic framework in which UC-MSCs adapt to 3D ECM stiffness through Piezo1-dependent mechanosensing. This work provides conceptual and practical guidance for the design of mechanically programmable biomaterials, the optimization of MSC-based regenerative strategies, and therapeutic approaches aimed at modulating pathological tissue mechanics such as fibrosis.