Three-dimensional spherical spatial boundary conditions differentially regulate osteogenic differentiation of mesenchymal stromal cells

Abstract

The spatial boundary condition (SBC) arising from the surrounding microenvironment imposes specific geometry and spatial constraints that affect organogenesis and tissue homeostasis. Mesenchymal stromal cells (MSCs) sensitively respond to alterations of mechanical cues generated from the SBC. However, mechanical cues provided by a three-dimensional (3D) environment are deprived in a reductionist 2D culture system. This study investigates how SBC affects osteogenic differentiation of MSCs using 3D scaffolds with monodispersed pores and homogenous spherical geometries. MSCs cultured under SBCs with diameters of 100 and 150 μm possessed the greatest capability of osteogenic differentiation. This phenomenon was strongly correlated with MSC morphology, organization of actin cytoskeleton, and distribution of focal adhesion involving α2 and α5 integrins. Further silencing either α2 or α5 integrin significantly reduced the above mentioned mechanosensitivity, indicating that the α2 and α5 integrins as mechano-sensitive molecules mediate MSCs’ ability to provide enhanced osteogenic differentiation in response to different spherical SBCs. Taken together, the findings provide new insights regarding how MSCs respond to mechanical cues from the surrounding microenvironment in a spherical SBC, and such biophysical stimuli should be taken into consideration in tissue engineering and regenerative medicine in conjunction with biochemical cues.

Hot isostatic pressure treatment of 3D printed Ti6Al4V alters surface modifications and cellular response

“…The addition of biomimetic architecture most likely contributes through altered cytoskeletal reorganization that activates signaling pathways which increase osteoblast response. Previous studies have shown that cytoskeletal reorganization in response to implant surface or cell spanning of pores results in increased production of osteoblast markers (Lai et al, ; Li et al, ; Lo et al, ).…”

Surface Curvature Differentially Regulates Stem Cell Migration and Differentiation via Altered Attachment Morphology and Nuclear Deformation

“…Numerous studies have shown that the mechanical properties of the cell's microenvironment, such as the substrate stiffness, have a fundamental effect on hMSC cell fate and function and impact tissue regeneration 6, 7, 8, 9. Recently, evidence is rising that the geometrical properties of the cell's environment also play an important role as regulators of cell behavior 10, 11, 12, 13, 14, 15, 16, 17, 18, 19. Using geometric features, such as pore geometry, as a cue to direct tissue regeneration is compelling since it may allow a biomaterial to steer cell function purely by its shape and hereby contribute to tissue regeneration.…”

“…Furthermore, there are first indications that also single cell behavior is influenced by 3D surface curvature as cells were observed to actively migrate out of concave pits, while cells attached and proliferated on convex structures 11. Recently, it was shown that the diameter of 3D spherical pores in scaffold structures has an impact on cell morphology and osteogenic differentiation of MSCs 15. Together, these studies give the first evidence that cell behavior and organization are altered by curvatures much larger than the cell size.…”

Multilayered membranes with tuned well arrays to be used as regenerative patches

“…Cell migration was clearly affected by the presence of the wells on the membrane; the presence of the geometrical cues led cells to migrate and start to adhere in the borders of the wells and proliferate to the centre direction. A recent study [72] shown that the diameter of 3D spherical pores could has influence on cellular morphological changes and osteogenic differentiation, even when curvatures are much larger than cell size. Herein, we developed concave spherical structures with a diameter of 500 µm (principle curvature (κ) = 1/250 µm −1 ), much larger than the size of SaOs-2 cell in a spread shape.…”