Bone Cells Grown on Micropatterned Surfaces are More Sensitive to Fluid Shear Stress

Bone has the ability to adapt its structure to meet its mechanical environment. In spite of great efforts to understand the mechanisms underlying this phenomenon, little is known about bone mechanotransduction at the cellular level. In this work, we propose that there is an interaction between the architecture of the cell and mechanosensitivity. Specifically, we hypothesized that cell spreading plays an important role in bone cell mechanotransduction. To test our hypothesis, we utilized micropatterned surfaces that allowed us to control the degree of cell spreading. Focal adhesion area is also known to depend on cell spreading. Thus patterns were utilized that maintained a constant total adhesive contact area, but permitted differing degrees of spreading. MC3T3-E1 osteoblasts cultured on these patterned surfaces were exposed to dynamic fluid shear stress. The fluid flow-induced changes in intracellular calcium [Ca2+]i were determined as a function of the degree of spreading. Cells grown on micropatterned surfaces were more responsive in general than those grown on traditional unpatterned surfaces. Interestingly, however, we found that cells with a higher degree of spreading were less responsive to mechanical loading. This work provides new insights into the interplay of cellular structure and mechanotransduction.