The Effect of Direct Co-culture of Adipose-derived MSCs and Murine Macrophages on Response to LPS In Vitro

Introduction: We investigated whether the interaction of mesenchymal stem cells (MSCs) with macrophages could play a significant role in the macrophage response to lipopolysaccharide (LPS) and their anti-inflammatory/immune-modulatory effects.Methods: BALB/C-adipose-derived MSCs were characterized by assessment of cell surface marker expression (cluster of differentiation (CD) 29, CD11b, CD73, CD105, spinocerebellar ataxia type 1 (Sca1), and CD45), and their capacity of differentiation into osteocytes and adipocytes. Co-culture of isolated MSCs with macrophages was done and RNA expression profiles, cytokine, and Nitric Oxide levels were assessed.Results: Macrophages co-cultured with MSCs treated with LPS significantly decreased the protein and mRNA expression of inducible nitric oxide synthase (iNOS), compare to macrophages treated with LPS in the absence of MSCs. Furthermore, these LPS treated MSC-educated macrophages expressed high levels of Tumor necrosis factor α (TNF-α) and low levels of Interleukin 10 (IL-10) and transforming growth factor β1(TGF-β1), as determined by inflammatory and anti-inflammatory cytokine, respectively. However, MSC-educated macrophages results showed that the IL-10 and TGF-β1 significantly increased, and TNF-α decreased in the co-cultured system compared with macrophages cultured alone.Conclusions: We describe a type of macrophage generated in vitro, as MSC-educated macrophages, which may be a unique type of alternatively activated macrophage with a potentially significant role in tissue repair.