The anti-inflammatory property of human bone marrow-derived mesenchymal stem/stromal cells is preserved in late-passage cultures

• hMSCs decreased NO level of IFNγ-activated BV-2 in a cell density dependent manner.
• hMSCs decreased NO level of IFNγ-activated BV-2 by cell-cell communication.
• Aged hMSCs decreased differentiation but maintained NO suppressive ability.
• hMSCs suppressed NO production in IFNγ activated primary microglia/macrophage.

Human mesenchymal stem/stromal cells (hMSCs) have been reported to improve neural damage via anti-inflammation and multi-differentiation abilities. Here, we investigated immunosuppression effects of hMSCs by mixed-culturing with interferon-γ (IFNγ) stimulated BV-2 mouse microglial cells. We show that hMSCs decreased nitrite oxide (NO) production from BV-2 cells in cell density dependent manner. Aged hMSCs and peroxisome proliferator-activated receptor-γ (PPARγ) knockdown hMSCs decreased differentiation abilities but maintained NO suppressive function. We finally confirmed NO suppression activities of hMSCs in IFNγ-stimulated primary microglia/macrophages. It suggested that hMSCs significantly modified NO production in activated phagocytes and it might be preserved in late passage cultures.