Remodeling of Three-Dimensional Collagen I Matrices by Human Bone Marrow Stromal Cells during Osteogenic Differentiation In Vitro

Abstract

Cell fate is triggered by the characteristics of the surrounding extracellular matrix (ECM) including its composition and topological and mechanical properties. Human bone marrow stromal cells (hBMSC) are known to reside in a niche environment where they are maintained in a quiescent, multipotent state, also controlled by the ECM characteristics. In this in vitro study, three-dimensional (3D) fibrillary collagen I (Col)-based matrices with defined topological and mechanical characteristics were used (pore size of 3–4 μm, fibril diameter of ∼0.7 μm, ∼90 Pa (non-cross-linked), and ∼160 Pa (cross-linked)), mimicking conditions of the environment in the bone marrow. The performance of non-cross-linked and cross-linked scaffolds during osteogenic differentiation of hBMSC in terms of matrix stiffness and proteolytic degradability was investigated. Cell adhesion, morphology, and invasion as well as matrix remodeling were investigated on cross-linked and non-cross-linked Col matrices over 22 days. About 25% of the cells invaded the matrices and showed a spread morphology independent of cross-linking. Cellular proteolytic matrix degradation in terms of a decreased matrix layer thickness was only found for non-cross-linked matrices at constant pore size and fibril diameter. Osteogenic differentiation of hBMSC was examined by alkaline phosphatase staining and enzyme activity (early marker) and calcium phosphate deposition (late marker) and was similarly supported in both scaffolds. Furthermore, both matrices were strongly stiffened by about 10-fold because of high mineralization under osteogenic conditions. In summary, these results emphasize that fibrillary 3D Col matrices are a suitable model to study primary hBMSC behavior in terms of ECM remodeling during osteogenesis at defined in vitro conditions.

Differential Smad2/3 linker phosphorylation is a crosstalk mechanism of Rho/ROCK and canonical TGF-β3 signaling in tenogenic differentiation

“…However, the different stiffness of the respective cell culture substrates will likely have influenced the activation of other signaling cascades. Tissue culture plastics have a much higher stiffness of 1 × 10 7 kPa in comparison to collagen matrices, which can be reconstituted in the range of 10 Pa to 50 kPa 38 – 40 . On stiff scaffolds, MSCs showed reduced tenogenic differentiation and increased activation of the FAK-ERK1/2 signaling pathway compared to softer scaffolds 41 , 42 .…”

Differential Smad2/3 linker phosphorylation is a crosstalk mechanism of Rho/ROCK and canonical TGF-β3 signaling in tenogenic differentiation

“…However, the different stiffness of the respective cell culture substrates will likely have in uenced the activation of other signaling cascades. Tissue culture plastics have a much higher stiffness of 1 x 10 7 kPa in comparison to collagen matrices, which can be reconstituted in the range of 10 Pa to 50 kPa [38][39][40]. On stiff scaffolds, MSCs showed reduced tenogenic differentiation and increased activation of the FAK-ERK1/2 signaling pathway compared to softer scaffolds [41,42].…”

Osteogenic Potential of Additively Manufactured TiTa Alloys

“…In this study, to account for the heterogeneity in behavior of hBMSCs, passage six cells were used from five independent donors. This study utilized hBMSCs as they are commonly used to model osteogenic response for new implant materials and tissue scaffolds. ,− MSCs are critical for implant success in the body as they are largely responsible for bone repair and remodeling as well as enhancing generalized wound healing. hBMSCs are also primary human cells, which are more predicative of an in vivo or clinical response than nonhuman or immortalized cell lines, such as L929 and SaOS2s.…”