Mesenchymal Stromal Cell-Derived Microvesicles Regulate an Internal Pro-Inflammatory Program in Activated Macrophages.

ABSTRACT: Mesenchymal stromal cells (MSCs) are multipotent cells with abilities to exert immunosuppressive response promoting tissue repair. Studies have shown that MSCs can secrete extracellular vesicles (MVs-MSCs) with similar regulatory functions to the parental cells. Furthermore, strong evidence suggesting that MVs-MSCs can modulate several immune cells (i.e., Th1, Th17, and Foxp3⁺ T cells). However, their precise effect on macrophages (M?s) remains unexplored. We investigated the immunoregulatory effect of MVs-MSCs on activated M1-M?s in vitro and in vivo using differentiated bone marrow M?s and an acute experimental model of thioglycollate-induced peritonitis, respectively. We observed that MVs-MSCs shared surface molecules with MSCs (CD44, CD105, CD90, CD73) and expressed classical microvesicle markers (Annexin V and CD9). The in vitro treatment with MVs-MSCs exerted a regulatory-like phenotype in M1-M?s, which showed higher CD206 level and reduced CCR7 expression. This was associated with decreased levels of inflammatory molecules (IL-1?, IL-6, nitric oxide) and increased immunoregulatory markers (IL-10 and Arginase) in M1-M?s. In addition, we detected that MVs-MSCs promoted the downregulation of inflammatory miRNAs (miR-155 and miR-21), as well as, upregulated its predicted target gene SOCS3 in activated M1-M?s. In vivo MVs-MSCs treatment reduced the M?s infiltrate in the peritoneal cavity inducing a M2-like regulatory phenotype in peritoneal M?s (higher arginase activity and reduced expression of CD86, iNOS, IFN-?, IL-1?, TNF-?, IL-1?, and IL-6 molecules). This in vivo immunomodulatory effect of MVs-MSCs on M1-M?s was partially associated with the upregulation of CX3CR1 in F4/80⁺/Ly6C⁺/CCR2⁺ M?s subsets. In summary, our findings indicate that MVs-MSCs can modulate an internal program in activated M?s establishing an alternative regulatory-like phenotype.

SUBMITTER: Henao Agudelo JS 

PROVIDER: S-EPMC5535070 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature