Extracelular vesicles derived from mesenchymal stromal cells modulate immune cells, generating a regulatory profile.
Year: 2019
Type: dissertation
Abstract: Introduction: Mesenchymal stromal cells (MSCs) can generate immunological tolerance due to their modulatory activity in T and B cells, dendritic cells (DCs) and natural killer cells. Extracellular vesicles (EVs) are one of the main mechanisms by which MSCs exert their actions. Objectives: In this study, our objective was to evaluate whether MSCs-EVs can, by themselves, modulate the immune response, generating a regulatory profile. Methods: MSCs were expanded and EVs were obtained by ultracentrifugation of the supernatant. Bone marrow-DCs were expanded with GM-CSF. The incorporation of MSCEVs by DCs and T cells was detected by confocal microscopy. Expression of surface markers was detected by flow cytometry (FACS) and cytokines were detected by RTPCR, ELISA, FACS and confocal microscopy. A miRNA PCR array was performed to evaluate the expression profile of miRNAs. Results: We demonstrated that MSC-EVs were incorporated by DCs and lymphocytes in vitro. Treatment with MSC-EVs did not affect the expression of surface markers on DCs, but affected their function, mainly by the increase of IL-10 protein. In addition, TCD4+ cells in the presence of DCs pretreated with MSC-EVs demonstrated less differentiation for a Th1 profile (IFNγ+) when compared to untreated DCs. When the effect of MSC-EVs was evaluated directly on T cells, addition of EVs induced less proliferation and less Th1 differentiation. Interestingly, in a specific Th1 polarization, the addition of MSC-EVs increased Foxp3 expression, also generating subpopulations of IFNγ+/Foxp3+ T cells. Previous treatment with RNAse appeared to partially abolish some of the functions, suggesting an important role of RNAs/miRNAs in this regulation. Finally, we observed a differential expression profile of miRNAs in Th1 cells treated with MSC-EVs, as well as modulation of one of their target genes, TGFbR2. The treatment with EVs also altered the mitochondrial metabolism of Th1-differentiated T cells, suggesting the involvement of the TGFβ pathway in this metabolic modulation. Conclusions: Our data suggest that MSCs-EVs are able to modulate the immune response, generating a regulatory profile, especially in activated T cells.
Language: Portuguese
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7120614275