Hydrogel biophysical properties instruct coculture-mediated osteogenic potential.
Kaitlin C Murphy1, Roberta S Stilhano1, Debika Mitra1
1*Department of Biomedical Engineering and Department of Orthopaedic Surgery, School of Medicine, University of California, Davis, Davis, California, USA; and Department of Biophysics, Federal University of Sao Paulo, Sao Paulo, Brazil.
Summary
Engineered hydrogel stiffness enhances bone formation by instructing co-implanted mesenchymal stem/stromal cells (MSCs) and endothelial colony-forming cells (ECFCs). Increased stiffness boosts osteogenic and proangiogenic potential, mediated by ECFC-derived bone morphogenetic protein-2 (BMP-2).
Area of Science:
- Biomaterials Science
- Regenerative Medicine
- Tissue Engineering
Background:
- Cell-based bone regeneration requires environmental cues.
- Co-implantation of mesenchymal stem/stromal cells (MSCs) and endothelial colony-forming cells (ECFCs) offers a promising strategy for bone formation and vascularization.
- The biophysical properties of the carrier material can influence cell behavior.
Purpose of the Study:
- To investigate how the mechanical properties of engineered hydrogels influence the osteogenic and proangiogenic potential of co-cultured MSCs and ECFCs.
- To determine the role of ECFC-derived bone morphogenetic protein-2 (BMP-2) in mediating the observed cellular responses.
- To assess the translational potential of cell co-implantation strategies for bone repair.
Main Methods:
- Fabrication of fibrin hydrogels with varying compressive stiffness.
- Co-culture of human MSCs and ECFCs within engineered hydrogels.
- Assessment of osteogenic differentiation and proangiogenic potential of the co-cultured cells.
- Quantification of BMP-2 secretion by ECFCs.
- Genetic manipulation of ECFCs to knockdown BMP-2 expression.
Main Results:
- Increased hydrogel stiffness significantly enhanced both osteogenic and proangiogenic potential of co-cultured MSCs and ECFCs compared to MSCs alone.
- ECFCs secreted BMP-2, and its secretion levels positively correlated with hydrogel stiffness.
- Knockdown of BMP-2 in ECFCs abrogated the enhanced osteogenic response in MSCs, highlighting BMP-2's critical role.
- Engineered hydrogel stiffness modulated cellular functions independently of exogenous inductive cues.
Conclusions:
- The biophysical properties of engineered hydrogels, specifically stiffness, play a crucial role in instructing co-cultured MSCs and ECFCs for enhanced bone formation and vascularization.
- ECFCs contribute to MSC osteogenesis via BMP-2 secretion, with production levels dependent on matrix stiffness.
- This study demonstrates the potential of rationally designed biomaterials to guide cell behavior for improved bone regeneration therapies.
