Effect of exosomes on fibroblast proliferation, migration, and angiogenic potential in 2D cultures

Abstract

Exosomes (EXs) which derived from umbilical cord mesenchymal stem cells (UCMSCs) have been emerging as a therapeutic candidate for tissue regeneration and wound healing due to their ability to modulate cellular functions. This study aimed to evaluate the internalization of UCMSC-derived EXs into fibroblasts and their effects on fibroblast proliferation, migration, and angiogenesis in vitro. EXs were isolated from UCMSC culture supernatants and characterized by transmission electron microscopy, revealing a typical cup-shaped morphology with an average size of approximately 100 nm. The ability of EXs to interact with target cells was assessed in a 2D fibroblast culture system, where rapid and efficient uptake was observed, reaching nearly complete internalization within 16 h. Functional assays demonstrated that UCMSC-derived EXs significantly enhanced fibroblast proliferation in a dose-dependent manner, with higher concentrations (50 and 100 µg/mL) producing stronger effects compared to lower doses. Similarly, EXs promoted fibroblast migration, as evidenced by accelerated wound closure in scratch assays, with the highest efficacy observed at 100 µg/mL. In contrast, the angiogenic effect of UCMSC-derived EXs on human umbilical vein endothelial cells showed a non-linear response. Enhanced tube formation was observed at an intermediate concentration (20 µg/mL), whereas higher doses exhibited reduced or inhibitory effects compared to the control group. These findings indicate that UCMSC-derived EXs play a multifaceted role in regulating key cellular processes involved in wound healing. However, their biological responses are strongly dose-dependent and vary across different cellular functions. Optimizing EX concentrations may therefore be critical for maximizing therapeutic outcomes in regenerative medicine.