Regulating osteogenesis and adipogenesis in adipose‐derived stem cells by controlling underlying substrate stiffness

Abstract

Cells reside in a complex microenvironment (niche) in which the biochemical and biophysical properties of the extracellular matrix profoundly affect cell behavior. Extracellular stiffness, one important bio-mechanical characteristic of the cell niche, is important in regulating cell proliferation, migration, and lineage specification. However, the mechanism by which mechanical signals guide osteogenic and adipogenic commitment of stem cells remains difficult to dissect. To explore this question, we generated a range of polydimethylsiloxane-based matrices with differing degrees of stiffness that mimicked the stiffness seen in natural tissues and examined adipose stem cell morphology, spreading, vinculin expression, and differentiation along the osteogenic and adipogenic pathways. Rigid matrices allowed broader cell spreading, faster growth rate and stronger expression of vinculin in adipose-derived stem cells. In the presence of inductive culture media, stiffness-dependent osteogenesis and adipogenesis of the adipose stem cells indicated that there was a combinatorial effect of biophysical and biochemical cues; no such lineage specification was observed in normal media. Osteogenic differentiation behavior showed a correlation with matrix rigidity, as well as with elevated expression of RhoA, ROCK-1/-2, and related proteins in the Wnt/β-catenin pathway. The result provides a comprehensive understanding of how stem cells respond to the surrounding microenvironment and points to the fact that matrix stiffness is a critical element in biomaterial design and this will be an important advance in stem cell-based tissue engineering.

Regulation and Directing Stem Cell Fate by Tissue Engineering Functional Microenvironments: Scaffold Physical and Chemical Cues

“…Stem cells differentiate into muscle cells on soft substrates and osteoblasts on harder substrates [86,87]. Another study supported this finding, and stem cell on soft materials when stiffness is less than 0.05 kPa could promote neural differentiation effectively, while hard stiffness materials (>40 kPa) promoted osteogenic differentiation effectively [88,89], which could be related to the Wnt signal pathway [90]. However, there is no agreement on the optimal stiffness for stem cells to differentiate into neurons, muscle cells, cartilage cells, and osteoblasts [86,91].…”

<p>Functionalized Graphene Nanoparticles Induce Human Mesenchymal Stem Cells to Express Distinct Extracellular Matrix Proteins Mediating Osteogenesis</p>

“…55,56 The results of the studies reported herein demonstrate that osteogenesis may be partially due to the rough topography of LOG nanoparticles, further supported by published studies. [57][58][59][60][61][62]…”

Tendon-Derived Stem Cell Differentiation in the Degenerative Tendon Microenvironment

“…Matrix stiffness, a biophysical cue in the cell microenvironment, played important roles in stem cell differentiation [ 24 – 26 ]. Mesenchymal stem cells (MSCs) [ 27 ], adipose-derived stem cells (ADSCs) [ 28 ], and umbilical cord mesenchymal stem cells (UCMSCs) [ 11 ], which were cultured on substrates with different stiffness, have been shown to possess diverse lineage commitments. MSCs would differentiate toward bone, muscle, or neuronal lineages as they grew on substrates with high, medium, or low stiffness, respectively [ 29 ].…”