Cellular mechanical properties reflect the differentiation potential of nucleus pulposus-derived progenitor cells

Mechanical properties of cells reflect differences in cellular subpopulations, differentiation potency, and cell behaviors. Previous study has revealed that intervertebral disc (IVD) degeneration leads to alterations in cell behavior and differentiation potency. Human nucleus pulposus-derived progenitor cells (NPPCs) are an attractive cell sources for IVD regeneration. However, the relationship between mechanical properties and differentiation potential in different NPPC subpopulations is few known. In this study, mechanical properties of different NPPC subpopulations were measured via atomic force microscopy (AFM) and correlated with differentiation potential of NPPCs. We found that elastic modulus, relaxed modulus, and instantaneous modulus were positively correlated with osteogenic potential of NPPCs. And apparent viscosity was correlated with chondrogenic potential of NPPCs. These results indicated that the mechanical properties were predictive markers for differentiation potential of NPPC subpopulations, and could be used for enrichment based on differentiation potential, which could significantly improve the outcome of IVD regeneration.