Comparing MSC-derived conditioned media and MSC-derived exosomes on M2-Macrophages differentiation in PBMCs

Background: Mesenchymal stem cells (MSCs) are well-known due to their immunomodulatory effects that could be mediated by paracrine factors and exosomes which are the major players in intercellular communications. In present study, we investigated the effect of MSC-conditioned media (MSC-CM) and MSC-derived exosomes on the expression of pro- and anti-inflammatory genes and IL-10 cytokine level in macrophages of Peripheral Blood Mononuclear Cells (PBMCs).Methods: Bone marrow-derived MSCs were verified by the osteoblastic and adipocytic differentiation and flow-cytometric analysis. MSC-exosomes were characterized by their size, concentration, and morphology. Afterwards, co-culture of isolated monocytes with MSC-CM and MSC-exosomes, and substantially characterization of macrophage population by flow-cytometry was performed. Gene expression of pro- and anti-inflammatory markers (IL-6, IL-12b, Arg-1, EGR-2, iNOS, and IL-10) in culture was evaluated by Real-time PCR. Moreover, IL-10 serum level was assessed by ELISA technique.Results: Regarding observed decrease in pro-inflammatory genes expression and elevated expression of anti-inflammatory ones, MSC-CM was more effective in phenotype shifting of monocytes to M2-macrophages. However IL-10 cytokine secretion level was higher in exosomes treated co-culture.Conclusion: Despite recent advances in cell-free therapies and applying immune-regulatory abilities of MSCs in clinic, little is known about the efficacy of MSC-CM comparing to MSC-exosomes. We showed that MSC-CM was more efficient in differentiating monocytes toward M2-macrophages and rendering them anti-inflammatory functionalities.

Keywords:

Mesenchymal Stem Cells , Conditioned media , Exosomes , Macrophages