Umbilical Cord Blood Mesenchymal Stem Cells Enhance Lipopolysaccharide-Induced IL-10 and IL-37 Production in THP-1 Cells.

Umbilical cord blood mesenchymal stem cells (UCB-MSCs) have been shown to be a source of stem cells for use in cellular therapies and have immunomodulatory effects on several immune cells in an inflammatory environment. However, whether UCB-MSCs have immunomodulatory effects against lipopolysaccharide (LPS)-induced inflammatory cytokine secretion in macrophages and whether it is involved in phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) signaling pathway remain unclear. After co-culture of UCB-MSCs and phorbol 12-myristate 13-acetate (PMA)-activated human THP-1 cells using a transwell system, it showed that LPS significantly induced increases in the expression levels of interleukin 10 (IL-10), interleukin 37 (IL-37), phospho-PI3K (p-PI3K), and phospho-Akt (p-Akt) in macrophages. UCB-MSCs upregulated the expression of IL-10, IL-37, p-PI3K, and p-Akt, while it had no obvious effect on PI3K and Akt levels. Inhibitors of PI3K (LY294002) significantly suppressed the expression of IL-10, IL-37, p-PI3K, and p-Akt; however, it had no effect on the expression levels of PI3K and Akt. The present study demonstrated that UCB-MSCs increased the LPS-stimulated expression of IL-10 and IL-37 in macrophages through the PI3K/Akt signaling pathway.