Differential TLR activation of murine mesenchymal stem cells generates distinct immunomodulatory effects in EAE

Abstract

BackgroundRecently, it has been observed that mesenchymal stem cells (MSCs) can modulate their immunoregulatory properties depending on the specific in-vitro activation of different Toll-like receptors (TLR), such as TLR3 and TLR4. In the present study, we evaluated the effect of polyinosinic:polycytidylic acid (poly(I:C)) and lipopolysaccharide (LPS) pretreatment on the immunological capacity of MSCs in vitro and in vivo.MethodsC57BL/6 bone marrow-derived MSCs were pretreated with poly(I:C) and LPS for 1 hour and their immunomodulatory capacity was evaluated. T-cell proliferation and their effect on Th1, Th17, and Treg differentiation/activation were measured. Next, we evaluated the therapeutic effect of MSCs in an experimental autoimmune encephalomyelitis (EAE) model, which was induced for 27 days with MOG35–55 peptide following the standard protocol. Mice were subjected to a single intraperitoneal injection (2 × 106 MSCs/100 μl) on day 4. Clinical score and body weight were monitored daily by blinded analysis. At day 27, mice were euthanized and draining lymph nodes were extracted for Th1, Th17, and Treg detection by flow cytometry.ResultsPretreatment of MSCs with poly(I:C) significantly reduced the proliferation of CD3+ T cells as well as nitric oxide secretion, an important immunosuppressive factor. Furthermore, MSCs treated with poly(I:C) reduced the differentiation/activation of proinflammatory lymphocytes, Th1 and Th17. In contrast, MSCs pretreated with LPS increased CD3+ T-cell proliferation, and induced Th1 and Th17 cells, as well as the levels of proinflammatory cytokine IL-6. Finally, we observed that intraperitoneal administration of MSCs pretreated with poly(I:C) significantly reduced the severity of EAE as well as the percentages of Th1 and Th17 proinflammatory subsets, while the pretreatment of MSCs with LPS completely reversed the therapeutic immunosuppressive effect of MSCs.ConclusionsTaken together, these data show that pretreatment of MSCs with poly(I:C) improved their immunosuppressive abilities. This may provide an opportunity to better define strategies for cell-based therapies to autoimmune diseases.

Immunity and ultrasonic vocalization in rodents

“…Furthermore, it should be remarked that exposure to LPS and poly I:C does not have exactly the same immunological consequences. For example, they have different qualitative or quantitative effects on T cell proliferation, cytokine production, types of cells recruited, and inflammatory mediators produced, and they have different effects on plasma and brain cytokine levels in the fetuses …”

Membrane particles generated from mesenchymal stromal cells modulate immune responses by selective targeting of pro-inflammatory monocytes

“…Recent work demonstrated that heat inactivated MSC that lost their capacity to secrete factors maintain their immunomodulatory capacity after intravenous infusion in an LPS-induced sepsis model, suggesting that cell membrane dependent interactions with immune cells are responsible for the immune regulatory effects 18 . MSC express immunomodulatory molecules on their membrane such as Toll-like receptors (TLRs) 19 , ATPases 20 and CD73 (ecto-5′-nucleotidase, Ecto5′NTase) which dephosphorylate ATP into AMP and AMP into adenosine, respectively 21 . This is an important immunomodulatory function as adenosine has immunosuppressive properties 22 .…”

IL17/IL17RA as a Novel Signaling Axis Driving Mesenchymal Stem Cell Therapeutic Function in Experimental Autoimmune Encephalomyelitis

“…5 days after EAE induction and clinical score and animal weight was recorded daily for 22 days. Clinical scores were calculated as previously described ( 38 ). Blood samples were collected from mouse tail veins at day 18 after EAE induction and the plasma was obtained after centrifugation (300 × g , 20 min).…”

“…The enzyme-linked immunosorbent assay (ELISA) for GM-CSF and the Enzyme Immunoassay kit for PGE2 (R&D Systems, USA) were used following manufacturer’s instructions with MSCs supernatants from cells activated or not with proinflammatory cytokines. NO 2 production was quantified in the supernatants of MSCs cocultured with Th17 cells for 5 days, using a modified Griess reagent (Sigma-Aldrich) as previously described by our group ( 38 , 39 ).…”