Effects of substrate stiffness and cell-cell contact on mesenchymal stem cell differentiation

Abstract

The mechanical properties of the microenvironment and direct contact-mediated cell-cell interactions are two variables known to be important in the determination of stem cell differentiation fate, but little is known about the interplay of these cues. Here, we use a micropatterning approach on polyacrylamide gels of tunable stiffnesses to study how homotypic cell-cell contacts and mechanical stiffness affect different stages of osteogenesis of mesenchymal stem cells (MSCs). Nuclear localization of transcription factors associated with osteogenesis depended on substrate stiffness and was independent of the degree of cell-cell contact. However, expression of alkaline phosphatase, an early protein marker for osteogenesis, increased only in cells with both direct contact with neighboring cells and adhesion to stiffer substrates. Finally, mature osteogenesis, as assessed by calcium deposition, was low in micropatterned cells, even on stiff substrates and in multicellular clusters. These results indicate that substrate stiffness and the presence of neighboring cells regulate osteogenesis in MSCs.

Fibrin structural and diffusional analysis suggests that fibers are permeable to solute transport

“…As our data demonstrates a strong effect of composition on structural and mechanical (bulk rheological) properties, these may be more important to consider for the optimization of fibrin hydrogels for a specific application. Measured storage moduli covered two orders of magnitude within a range that is known to affect cell behavior in terms of differentiation [10,65], and also independently from the material porosity [66]. Low fibrinogen concentrations with relatively low thrombin and factor XIII concentrations (such as 5LL…”

Single cell-laden protease-sensitive microniches for long-term culture in 3D

“…In this regard, in future work our approach can serve for studying the influence of a broad set of mechanical and biochemical matrix properties on single cells as well as the effects of a lack of cell–cell contact on cellular processes in 3D as was done in 2D to study osteogenic and adipogenic differentiation of MSCs. 34,35 In addition, the tunability of microniche size, elasticity and proteolytic degradability can be used to exactly control the time of cellular egress, which is potentially appealing for therapeutic applications where encapsulated cells are ideally protected during initial stages to promote engraftment and viability and later interact with the host’s cells to stimulate repair and regeneration. 36 Moreover, our approach allows for encapsulation of heterogeneous cell populations, e.g.…”

Review: Mechanotransduction in ovarian cancer: Shearing into the unknown

“…Cells can perceive the surrounding stiffness of their microenvironment and its modulation has been shown to heavily influence phenotype, 77,78 protein expression, 79,80 and differentiation. 81,82 For cancer cells, the stiffness of their surrounding ECM can influence metastasis, invasion, proliferation, and chemoresistance. [83][84][85][86] Numerous studies have proven that stiffer substrates enhance the metastatic phenotypes of cancer cells.…”