The study found that a short piece of the IGF‑1 protein, called MGF‑E, makes rat bone‑marrow stem cells move more by turning on the CXCR4‑ERK1/2 signaling pathway, which also makes the cells stiffer and changes their internal skeleton. This work was done in cell cultures, not in people, so it doesn’t give a direct way to use the peptide for health benefits yet.

Mechano growth factor (MGF) is a splicing variant of insulin-like growth factor 1 (IGF-1). The unique C-terminal E domain of MGF (MGF-E) makes it distinct from the other variants of IGF-1. Our previous work demonstrated that MGF-25E induces the migration of rat bone marrow-derived mesenchymal stem cells (rMSCs) by altering their mechanical properties, which is accompanied by the activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway. However, the relationship between ERK1/2 activation and the change in mechanical properties has not been illustrated. In the present study, we determined that MGF-25E induced the migration of rMSCs by modulating CXCR4 to activate the ERK1/2 pathway. The analysis of the Young's modulus and F-actin remodeling indicated that MGF-25E increased the stiffness and the F-actin polymerization of rMSCs through the activation of the CXCR4-ERK1/2 pathway. For the first time, this study clarified the signaling pathway that regulates the mechanical properties of rMSCs and is responsible for MGF-25E-promoted migration.