Concise Review: Mesenchymal Stem Cells Ameliorate Tissue Injury via Secretion of Tumor Necrosis Factor-α Stimulated Protein/Gene 6

Figure 3

Anti-inflammatory action of MSCs is mediated mainly through TSG-6. Damage-associated molecular patterns (DAMPs), as a result of tissue injury, activated resident macrophages via Toll like receptors (TLRs) and nuclear factor-κB (NF-κB) to increase the expression of proinflammatory cytokines. In addition, the target cells could also secrete a number of proinflammatory cytokines when they were damaged. In turn, the production of cytokines and other signals would engage MSCs to secrete TSG-6, which negatively regulated TLRs/NF-κB signaling through binding the CD44 receptors on the macrophages or suppress inflammation via extracellular matrix (ECM) reorganization.