The researchers have previously developed xeno‑free induced MSCs (XF‑iMSCs) from human iPS cells via a neural crest cell lineage and confirmed that they express classical MSC markers, including CD44, CD73, and CD105, as well as their ability to differentiate into cartilage, bone, and adipose tissues. XF‑iMSCs were originally established to overcome major limitations of tissue‑derived MSCs, including donor‑dependent variability, limited proliferation capacity, and reliance on animal‑derived components during manufacturing. By enabling highly standardized, large‑scale production, XF‑iMSCs represent a robust alternative for clinical applications. Although their regenerative effects in bone and skeletal muscle were demonstrated in earlier work, their potential roles in immune regulation had not yet been explored, prompting this study to investigate their anti‑inflammatory and immunomodulatory functions.

Through a series of human and mouse cell‑based assays, the team demonstrated that XF‑iMSCs can significantly suppress inflammatory cytokine production. When mouse or human peripheral blood mononuclear cells (PBMCs) were stimulated with lipopolysaccharide, XF‑iMSCs significantly reduced production of IL‑6 and TNF‑α, two key cytokines involved in acute and chronic inflammation. At the same time, XF‑iMSCs increased levels of IL‑10, an anti‑inflammatory cytokine that helps restore immune balance. These results confirm that iPSC‑derived MSCs are capable of modulating innate immune responses similar to clinically used adipose-, bone marrow‑, and umbilical cord‑derived MSCs.

In addition to these cellular effects, the researchers examined extracellular vesicles (EVs) released by XF‑iMSCs. After purifying the vesicles, they found that concentrated XF‑iMSC‑EVs strongly suppressed IL‑6 and TNF‑α secretion in mouse PBMCs and reduced IL‑2, IFN‑γ, and IL‑17 levels in activated splenocytes, indicating potent regulation of both innate and adaptive immune pathways. In human PBMC assays, XF‑iMSC‑EVs effectively lowered TNF‑α but had minimal effect on IL‑6, suggesting that EV‑mediated pathways may be selectively cytokine‑specific. Proteomic analysis revealed 1,217 proteins within XF‑iMSC‑EVs, including unique factors such as midkine, pleiotrophin, IGSF3, LTBP4, and Shisa‑2--proteins associated with neural development, skeletal muscle biology, and immune modulation. These findings raise the possibility that XF‑iMSC‑EVs may also contribute to regenerative processes beyond immunoregulation.

In T‑cell suppression assays, XF‑iMSCs robustly inhibited proliferation of effector T cells, achieving nearly 80% suppression at a 0.5:1 MSC:PBMC ratio. EVs alone did not replicate this effect, highlighting that certain immunomodulatory functions depend on direct cell‑cell interactions rather than secreted factors. Importantly, neither XF‑iMSC‑EVs nor adipocyte‑MSC‑EVs impaired PBMC viability, indicating that reduced cytokine levels were not due to cell death.

Together, these results establish XF‑iMSCs as a scalable alternative—free of animal components—to primary MSCs with strong anti-inflammatory and immunomodulatory effects. The researchers now plan to evaluate how XF‑iMSC‑EVs influence macrophage polarization and to test both XF‑iMSCs and their EVs in mouse models of graft‑versus‑host disease, inflammatory bowel disease, and atopic dermatitis. Looking forward, the team envisions advancing XF iMSCs and their extracellular vesicles toward clinically viable, next generation immunomodulatory therapies that could address a wide range of currently untreatable inflammatory and autoimmune conditions.

• doi: 10.1016/j.reth.2026.101081