Priming with inflammatory cytokines is not a prerequisite to increase immune-suppressive effects and responsiveness of equine amniotic mesenchymal stromal cells

Abstract

Background: Equine amniotic mesenchymal stromal cells (AMSCs) and their conditioned medium (CM) were evaluated for their ability to inhibit in vitro proliferation of peripheral blood mononuclear cells (PBMCs) with and without priming. Additionally, AMSC immunogenicity was assessed by expression of MHCI and MHCII and their ability to counteract the in vitro inflammatory process. Methods: Horse PBMC proliferation was induced with phytohemagglutinin. AMSC priming was performed with 10 ng/ml of TNF-α, 100 ng/ml of IFN-γ, and a combination of 5 ng/ml of TNF-α and 50 ng/ml of IFN-γ. The CM generated from naïve unprimed and primed AMSCs was also tested to evaluate its effects on equine endometrial cells in an in vitro inflammatory model induced by LPS. Immunogenicity marker expression (MHCI and II) was evaluated by qRT-PCR and by flow cytometry.Results: Priming does not increase MHCI and II expression. Furthermore, the inhibition of PBMC proliferation was comparable between naïve and conditioned cells, with the exception of AMSCs primed with both TNF-α and IFN-γ that had a reduced capacity to inhibit T cell proliferation. However, AMSC viability was lower after priming than under other experimental conditions. CM from naïve and primed AMSCs strongly inhibited PBMC proliferation and counteracted the inflammatory process, rescuing about 65% of endometrial cells treated by LPS.Conclusion: AMSCs and their CM have a strong capacity to inhibit PBMC proliferation, and priming is not necessary to improve their immunosuppressive activity or reactivity in an inflammatory in vitro model.

Interferon-gamma and TNF-alpha synergistically enhance the immunomodulatory capacity of Endometrial-Derived Mesenchymal Stromal Cell secretomes by differential microRNA and extracellular vesicle release

“…Our functional studies using in vitro stimulated lymphocytes (that partially mimic an antigen-specific activation of T cells) could demonstrate their immunomodulatory capacity, however, further studies need to be performed to identify targeted genes in different immune cells. In a very recent study (81) equine amniotic MSCs were primed with a combination of IFNγ and TNFα demonstrating no additional immunosuppressive activity in an inflammatory in vitro model, compared to non-primed cells. Even though this study was performed with lower concentrations of IFNγ and TNFα on a different type of MSCs, it remarks that further research is necessary to confirm our insights.…”

Targeting the chromatin structural changes of antitumor immunity

“…The tumor microenvironment is usually associated with immunosuppressive cells, which have negative effects on the activation, migration, and proliferation of T cells. MDSCs, immature DCs, macrophages, and Tregs [ 65 ] are known to have key roles in the tumor microenvironment [ 66 ]. Many Treg-specific epigenetic characteristic genes, such as CTLA4 , IKZF4 (EOS), and TNFRSF18 (GITR), show complete demethylation, which allows fork box P3 (FOXP3) T cells to obtain Treg characteristic gene expression, lineage stability, and specific immunosuppressive activity [ 67 ].…”

Application of Perinatal Derivatives in Ovarian Diseases

“…It has also been suggested that several types of PnD can be used for allogeneic transplantation without rejection because they show hypo immunogenicity and the ability to modulate immune responses ( Li et al, 2017 ; Ling et al, 2019 ). Compared to bone marrow-MSC, that are not able to exert suppressive effects if they are not previously exposed to inflammatory stimuli, PnD do not require “licensing” with inflammatory stimuli such as interferon (IFN) and tumor necrosis factor-α (TNF-α) ( Lange-Consiglio et al, 2020 ; Papait et al, 2020 ). Moreover, PnD produce higher levels of cytokines and growth factors as compared to bone marrow-MSC and adipose-MSC, including granulocyte colony-stimulating factor (G-CSF), regulated on activation, normal T cell expressed and secreted (RANTES) and interleukin (IL)-6/-8/-10 ( Seok et al, 2020 ).…”