Volume expansion and TRPV4 activation regulate stem cell fate in three-dimensional microenvironments

Area of Science:

• Biomedical Engineering
• Stem Cell Biology
• Biomaterials Science

Background:

• Matrix remodeling in 3D cultures enhances osteogenic differentiation of mesenchymal stem cells (MSCs).
• The precise mechanisms connecting 3D matrix remodeling to MSC osteogenesis remain largely unelucidated.

Purpose of the Study:

• To investigate the role of cell volume changes during cell spreading in 3D matrices.
• To identify the molecular pathways linking matrix viscoelasticity to osteogenic differentiation in MSCs.

Main Methods:

• Culturing MSCs in viscoelastic hydrogels with controlled mechanical properties.
• Manipulating cell volume using osmotic pressure and assessing osteogenic markers.
• Investigating the involvement of TRPV4 ion channels and RUNX2/YAP nuclear localization.

Main Results:

• MSCs in viscoelastic hydrogels exhibited volume expansion correlated with enhanced osteogenesis.
• Restricting cell volume expansion diminished osteogenesis, while induced expansion accelerated it.
• TRPV4 channel activation mediated volume expansion and osteogenesis via RUNX2 nuclear localization.

Conclusions:

• Cell volume is a critical regulator of MSC fate in 3D culture.
• TRPV4 acts as a mechanosensor translating matrix viscoelasticity into osteogenic differentiation signals.