Microgravity-driven Rab27B activation amplifies mesenchymal stem cell-derived extracellular vesicle production and functions.

BACKGROUND

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are emerging as promising treatments for immunomodulation and tissue regeneration. However, the scalable production of functionally enhanced EVs remains a critical challenge. This study introduces microgravity culture using a three-dimensional (3D) rotating cell culture system as a novel strategy to optimize MSC-EVs yield and bioactivity.

METHODS

We first investigated the effects of microgravity on the proliferation and stemness of human umbilical cord-derived MSCs (UCMSCs). The yield of microgravity-derived EVs (µg-EVs) was quantified by nanoparticle tracking analysis. The function of µg-EVs was analyzed by proteomic profiling and further assessed by macrophage polarization and osteogenic differentiation of periodontal ligament stem cells (PDLSCs). Proteomic analysis of UCMSCs was performed to further explore the underlying mechanisms of EVs biogenesis and functional activity under microgravity condition.

RESULTS

Microgravity culture significantly enhanced UCMSCs proliferation and stemness. Compared with conventional static culture, EVs production increased by 7.7-fold under microgravity. Functionally, µg-EVs more effectively promoted macrophage polarization toward the anti-inflammatory M2 phenotype and significantly enhanced the osteogenic differentiation capacity of PDLSCs. Mechanistically, Rab27B upregulation in microgravity-cultured UCMSCs was associated with increased EVs secretion and enhanced therapeutic efficacy.

CONCLUSIONS

This study identifies microgravity as an effective platform for the large-scale production of high-quality UCMSC-EVs, addressing key manufacturing barriers and accelerating the clinical translation of EVs-based therapies.