Review of the potential of mesenchymal stem cells for the treatment of infectious diseases

Figure 2 Immunomodulation by mesenchymal stem cells. Mesenchymal stem cells (MSCs) secrete various paracrine factors and chemokines to reduce inflammation at the site of injury by inhibiting infiltration of neutrophils, pro-inflammatory monocytes, and maturation of dendritic cells[39,62,219]. MSCs promote anti-inflammatory M2 phenotype in macrophages, improve phagocytic ability and increase their survival via mitochondrial transfer[12,43-45,48]. MSCs under inflammatory conditions inhibit T-cell proliferation via secretion of programmed death-ligand 1 (PD-L1) and PD-L2[54]. MSCs induce a “tolerogenic” phenotype in monocytes and promote migration of regulatory T cells to the site of infection[58,60]. Ang1: Angiopoietin-1; EVs: Extracellular vesicles; HGF: Hepatocyte growth factor; KGF: Keratinocyte growth factor; LXA: LipoxinA₄; MMPs: Matrix metalloproteinases; VEGF: Vascular endothelial growth factor.