Mesenchymal stem cell–educated macrophages: A novel type of alternatively activated macrophages

Abstract

Objective-Mesenchymal stem cells (MSCs) are capable of modulating the immune system through interaction with a wide range of immune cells. This study investigates the hypothesis that interaction of MSCs with macrophages could play a significant role in their anti-inflammatory/ immune modulatory effects.Materials and Methods-MSCs were derived from bone marrow and monocytes were isolated from peripheral blood of healthy donors. We cultured human monocytes for seven days without any added cytokines to generate macrophages, and then co-cultured them for three more days with culture-expanded MSCs. We used cell surface antigen expression and intracellular cytokine expression patterns to study the immunophenotype of macrophages at the end of this co-culture period, and phagocytic assays to investigate their functional activity in vitro.Results-Macrophages co-cultured with MSCs consistently showed high level expression of CD206, a marker of alternatively activated macrophages. Furthermore, these macrophages expressed high levels of IL-10 and low levels of IL-12, as determined by intracellular staining, typical of alternatively activated macrophages. However, macrophages co-cultured with MSCs also expressed high levels of IL-6 and low levels of TNF-α, compared to controls. Functionally, macrophages cocultured with MSCs showed a higher level of phagocytic activity.Conclusions-We describe a novel type of human macrophage generated in vitro after co-culture with MSCs that assume an immunophenotype defined as IL-10 high, IL-12 low, IL-6 high and TNF-α low secreting cells. These MSC-educated macrophages may be a unique and novel type of alternatively activated macrophages with potentially significant role in tissue repair. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Keywords Conflict of Interest Disclosure:No financial interest/relationships with financial interest relating to the topic of this article have been declared. NIH Public Access Materials and methods Cell cultureWe used human blood and bone marrow to derive monocytes and MSCs, respectively. All protocols were approved by the Health Sciences Institutional Review Board of University of Wisconsin-Madison School of Medicine and Public Health. Monocytes were isolated from human peripheral blood by using magnetic bead separation methods according to manufacturers' protocol. Briefly, peripheral blood mononuclear cells were collected from blood of healthy donors by density gradient separation using Percoll (GE Healthcare Biosciences, Piscataway, NJ, USA). Red blood cells were lysed by incubating cells in ACK lysis buffe...

Mesenchymal Stromal Cells Modulate Macrophages in Clinically Relevant Lung Injury Models by Extracellular Vesicle Mitochondrial Transfer

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“…Among them, only expression of CD206 (a marker for M2 polarization [40]) demonstrated differential regulation by LPS and MSCs; MDM expression of CD206 was significantly increased by MSCs in both the presence (40 6 16% increase) and the absence (25 6 12% increase) of LPS ( Figure 1C). Notably, expression of CD163 (an established M2 marker [41]), although detectable, was not affected by any of the stimulations.…”

Mesenchymal Stem Cells Shape Microglia Effector Functions Through the Release of CX3CL1

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Extensive bone marrow necrosis resolved by allogeneic umbilical cord blood mesenchymal stem cell transplantation in a chronic myeloid leukemia patient

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