Immunomodulatory effect of mesenchymal stem cells on the immune response of macrophages stimulated by Aspergillus fumigatus conidia.

Mesenchymal stem cells (MSCs) are known to exert potent immunosuppression and anti-inflammatory effects. There is growing interest in their use for immunotherapy for controlling inflammation as well as acute organ injury. However, there are few reports regarding MSC's immunomodulatory effects in the settings of fungal infection. In this study, we attempted to examine the immunomodulatory effects of MSCs in response to Aspergillus fumigatus. We measured the cytokine response of murine MSCs on the immune response of murine macrophages (J774A. 1 cells) evoked by A. fumigatus conidia. In addition, we evaluated the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) on the MSC-related cytokine response and fungal growth. As a results, after conidia stimulation, tumor necrosis factor (TNF)-alpha was down-regulated and interleukin (IL)-10 was up-regulated in MSC-treated J774A. 1 cells when compared to J774A. 1 cells alone. In addition, fungal growth was reduced in MSC-treated J774A. 1 cells when compared to J774A. 1 cells, which recovered by GM-CSF. However, the effect of MSCs on the cytokine response was not reversed by GM-CSF. NF-kappa B translocation decreased in MSC-treated J774A. 1 cells compared to J774A. 1 cells alone. In conclusion, MSCs demonstrate immunomodulatory properties in both aspects of cytokines and fungal growth. The antiinflammatory effect of MSCs with regard to cytokine response might be associated with decreased NF-kappa B translocation, and is not reversed by GM-CSF.