Interleukin-10-engineered mesenchymal stem/stromal cells exhibit robust immunomodulatory effects in vitro and in vivo

INTRODUCTION: A dysregulated inflammatory response to infection can lead to sepsis, a leading cause of mortality worldwide, and effective anti-inflammatory therapies remain limited. Mesenchymal stem/stromal cells (MSCs) are attractive candidates as immunomodulatory agents. This study evaluated whether genetic modification of MSCs to express interleukin-10 (IL-10), a key anti-inflammatory cytokine, enhances their immunomodulatory effects. METHODS: Bone marrow-derived MSCs from C57Bl/6 mice were genetically engineered by lentiviral transduction to express mouse IL-10 (MSC-IL-10). The immunomodulatory activity in vitro was assessed by co-cultures with macrophages stimulated with LPS and IFN-γ, as well as in Con A-stimulated splenocytes. BALB/c mice subjected to lipopolysaccharide (LPS)-induced endotoxemia were treated with vehicle, dexamethasone, wild-type MSCs (MSC-WT), or MSC-IL-10. Survival, plasma cytokines, leukocyte profiles, CD11b⁺ inflammatory cells, and organ histopathology and biodistribution were evaluated in vivo. RESULTS: MSC-IL-10 maintained the mesenchymal phenotype and multipotent characteristics while exhibiting robust IL-10 expression. In in vitro assays, MSC-IL-10 significantly decreased the production of the cytokines TNF-α, IL-1β, IL-6, IL-12 or Nos2 expression by stimulated macrophages or splenocytes, demonstrating superior immunomodulatory effects compared to MSC-WT. In in vivo mice models, MSC-IL-10 significantly reduced systemic pro-inflammatory cytokines, restored circulating leukocyte counts, and attenuated CD11b⁺ (Mac-1 integrin) inflammatory cell recruitment, surpassing MSC-WT-treated groups. Importantly, MSC-IL-10 mitigated tissue damage mainly to lungs and exhibited biodistribution to liver, lungs and spleen in LPS-challenged mice. CONCLUSIONS: These results support an enhanced immunomodulatory effect of IL-10-expressing MSCs as a promising cell-based therapeutic approach for sepsis and other inflammatory and immune mediated disorders.