Clonal Analysis of hASC Differentiation Potential and Mechanical Biomarkers

Investigators: Vera Fonseca and Rafael Gonzalez Cruz

Mesenchymal stem cells are a diffusely defined population of multipotent cells found in many different tissues. Therapeutic use of these cells is problematic since there is variability in the differentiation potential of individual cells, making it difficult to control which genes and proteins are expressed in response to a given stimuli. Traditional biochemical markers have had minimal success identifying a “stem cell marker.” However, recent findings indicate mechanical properties are linked to the phenotype of certain cell types. Therefore, the objective of this study was to investigate whether single-cell elastic and viscoelastic properties are an indicator of lineage differentiation potential in adipose-derived stem cells (ASCs). We found that cellular mechanical properties can predict the differentiation potential of ASCs. Undifferentiated stem cells that are large and compliant tend to be more adipogenic, while undifferentiated cells that are less compliant and more viscous exhibit more robust differentiation along osteogenic and chondrogenic lineages. Additionally, we asked whether sorting cells by mechanical biomarkers could produce populations with greater regenerative capacity. To investigate this possibility, we conducted simulations that inspected the mechanical properties of the top 25% of ASC clones for adipogenic, osteogenic and chondrogenic lineages. We found that “high potential” ASC clones had similar mechanical properties within each lineage. For example, ASCs exhibiting robust osteogenesis had relaxed moduli values above 200 Pa while ASCs exhibiting robust chondrogenesis had apparent viscosity values above 1.6 kPa·s. The results of these experiments indicate that cellular mechanical properties can be used as biomarkers to identify ASCs exhibiting lineage-specific preferences. The experimental findings comprising this project have been published in the journal Proceedings of the National Academy of Sciences and the research article can be accessed here.