Immunosuppression Of Mesenchymal Stem Cells Research Articles

Roles of PD-L1 in human adipose-derived mesenchymal stem cells under inflammatory microenvironment.

Mesenchymal stem cells (MSCs) display unique homing and immunosuppression features which make them promising candidates for cell therapy in inflammatory disorders. It is known that C-X-C chemokine receptor type 4 (CXCR4, also known as CD184) is a critical receptor implicated in MSCs migration, and the protein programmed death ligand-1 (PD-L1) is involved in MSC's immunosuppression. However, it remains unclear how the molecular mechanisms regulate PD-L1 expression for migration and immunosuppression of MSCs under the inflammatory microenvironment. In this article, we used the human adipose-derived mesenchymal stem cells (hADMSCs) treated with lipopolysaccharide (LPS) as an in vitro inflammatory model to explore the roles of PD-L1 on the migration and immunosuppression of MSC. Our results demonstrate that in hADMSCs, LPS significantly increased PD-L1 expression, which mediated the migration of the LPS-treated hADMSCs via CXCR4. In addition, we found that the increased PD-L1 expression in the LPS-treated hADMSCs inhibited B cell proliferation and immunoglobulin G secretion through nuclear factor-κB. Our study suggests that the PD-L1 plays critical roles in the homing and immunosuppression of MSCs which are a promising cell therapy to treat inflammatory diseases.

Interleukin 17 (IL-17)-Induced Mesenchymal Stem Cells Prolong the Survival of Allogeneic Skin Grafts.

BackgroundMesenchymal stem cells (MSCs) have the potential of self-renewal and multi-differentiation and have a wide application prospect in organ transplantation for the effect of inducing immune tolerance. It has found that interleukin 17 (IL-17) could enhance the inhibition effect of MSCs on T cell proliferation and increase the immunosuppressive effect of MSCs. In this study, we aimed to investigate the effect of IL-17-induced MSCs on allograft survival time after transplantation.Material/MethodsBMSCs were characterized by differential staining. The allogenic skin transplantations were performed and the BMSCs pre-treated by IL-17 were injected. To assess the immunosuppressive function of IL-17-induced BMSCs, the morphology of the grafts, the homing ability of the BMSCs, and the survival time of the grafts were analyzed.ResultsBMSCs from BALB/c have multidirectional differentiation potential to differentiate into osteogenic, chondrogenic, and adipogenic lineage cells. IL-17-induced BMSCs prolonged the survival time of allogeneic skin grafts dramatically. We found that there were more labeled MSCs in the skin grafts, and the Treg subpopulations percentage, IL-10, and TGF-β were significantly increased, while the IFN-γ level was decreased compared to the control group and MSCs group. In conclusion, IL-17 can enhance the homing ability of MSCs and regulate the immunosuppressive function of MSC.ConclusionsOur data demonstrate that IL-17 plays the crucial role in MSC homing behaviors and promotes immunosuppression of MSCs during transplantation procedures, suggesting that IL-17-pre-treated MSCs have potential to prolong graft survival and reduce transplant rejection.

Mesenchymal stem cells moderate immune response of type 1 diabetes.

Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by lack of insulin and irreversible destruction of islet β cells. In order to alleviate the symptoms, lifelong exogenous insulin administration has been the primary treatment of T1DM. In recent years, as a novel promising therapy, the transplantation of mesenchymal stem cells (MSCs) with or without pancreatic islets has achieved great therapeutic effects in animal models due to their multipotency along with their secretion of cytokines, angiogenic factors and immunomodulatory substances. There is plenty of evidence showing that MSCs can delay T1DM onset, reverse hyperglycemia after onset and increase insulin production. To date, the immunoregulation and immunosuppression of MSCs have been widely proved but the exact mechanisms are still not clear enough. Therefore, in this review, we mainly discuss the immunologic mechanism of MSCs in moderating the immune response of T1DM.

CD4(+)CD25 (+) regulatory T cells are not required for mesenchymal stem cell function in fully MHC-mismatched mouse cardiac transplantation.

Although the immunomodulative properties of mesenchymal stem cells (MSCs) open up attractive possibilities in solid-organ transplantation, information concerning the optimal dose, route, timing of administration, major histocompatibility complex (MHC)-restriction and relevant mechanisms is currently lacking. Therefore, better characterization of MSC immunoregulatory activity and elucidation of its mechanisms are crucial. In this study, we confirmed that MSCs did not elicit proliferation by allogeneic CD4(+) T cells, suggesting that MSCs were not immunogenic. By using C57BL/6 mouse MSCs as donor-derived or recipient-derived or as third-party MSCs, we discovered that MSCs suppressed CD4(+) T cell proliferation and prolonged mouse cardiac allograft survival in a dose-dependent and non-MHC-restricted manner. We also found that intraperitoneal administration favored survival prolongation, although this prolongation was weaker than that via the intravenous route. Only infusion at earlier time points favored survival prolongation. Depletion of CD4(+)CD25(+) T cells did not affect the immunosuppression of MSCs on CD4(+) T cells. Moreover, MSCs did not induce regulatory T cells. The in vivo data revealed that MSCs did not increase the percentage of CD4(+)CD25(+) T cells and FoxP3 expression. More importantly, we demonstrated for the first time that depletion of CD4(+)CD25(+) T cells did not hinder MSC-induced survival prolongation, indicating that CD4(+)CD25(+) regulatory T cells were not essential for the prolongation of MSC-mediated allograft survival.

Immunomodulatory properties of colonic mesenchymal stem cells

AimTo elucidate the immunomodulatory functions of colonic mesenchymal stem cells (MSCs) in the colonic mucosal immune system. MethodsThe colonic MSCs were isolated, enriched and expanded. The immunosuppressive role of colonic MSCs on activated T cells was evaluated. The cell cycle progression of T cells and the expression of FoxP3+ T cells were assessed by fluorescence-activated cell sorting (FACS). The levels of cytokines and PGE2 were measured by ELISA. ResultMouse colonic MSCs can inhibit the proliferation of activated T cells by arresting cells in G0/G1 phase, induce the expression of CD4+CD25+Foxp3+ T cells (8.05%±0.49% in transwell culture vs 8.45%±0.64% in direct contact culture vs 4.30%±0.28% in control, p<0.05), downregulate the levels of the cytokines TNF-α and IFN-γ, and increase the production of IL-10 (p<0.05). The data obtained from transwell culture and direct contact culture showed no difference (p>0.05). PGE2 level was increased when T cells were cultured with colonic MSCs (385.10±19.45ng/l in transwell culture vs 387.91±19.85ng/l in direct contact culture vs 276.21±25.49ng/l in control, p<0.05). Blocking PGE2 partially reversed the immunosuppression of MSCs on activated T cells proliferation (p<0.05). ConclusionColonic MSCs have the same immunosuppressive property as other MSCs. They performed their functions partially through secreting soluble factor PGE2. The characterization of these colonic MSCs may be helpful for studying the involvement of stromal cell compartment in colon diseases.

Мезенхімальні стовбурові клітини та їх імунні властивості

Mesenchymal stem cells (MSC) are found in a variety of tissues, including bone marrow, skin and adipose tissue and can be expanded easily in vitro. MSC are thought to have tissue regenerative properties, in the first place via their multilineage differentiation capacity. In addition, MSC have potent immunomodulatory capacity. They inhibit the proliferation of T cells and inhibit dendritic cell maturation. These properties make MSC promising for a diversity of clinical applications; for example, for the prevention and treatment of autoimmune diseases and bone marrow rejection. Different studies have attributed the immunosuppressive effect of MSC to different immunosuppressive factors. These include indoleamine 2,3-dioxygenase (IDO), HLA-G, nitric oxide, interleukines. The long-term ability of allogeneic MSCs to preserve function in the infarcted heart is limited by a biphasic immune response whereby they transition from an immunoprivileged to an immunogenic state after differentiation, which is associated with an alteration in major histocompatibility complex--immune antigen profile. These findings provide critical information about the immunosuppression of MSCs and for better application of MSCs in treating immune disorders.

The role of immunosuppression of mesenchymal stem cells in tissue repair and tumor growth

Mesenchymal stem cells (MSCs) have acquired great interests for their potential use in the clinical therapy of many diseases because of their functions including multiple lineage differentiation, low immunogenicity and immunosuppression. Many studies suggest that MSCs are strongly immunosuppressive in vitro and in vivo. MSCs exert a profound inhibitory effect on the proliferation of T cells, B cells, dendritic cells and natural killer cells. In addition, several soluble factors have been reported to involved in the immunosuppressive effects by MSCs such as TGF-β, HGF, PGE2, IDO and iNOS. These results suggest that MSCs can be used in the therapy of immune disorder diseases, prevention of organ transplantation rejection and tissue injury. In recent study, we demonstrated that MSCs in tumor inflammatory microenvironment might be elicited of immunosuppressive function. Thus, the application of MSCs in cancer therapy might have negative effect by helping tumor cells escaping from the immune surveillance.

Effect of FK506 on the immunosuppression of mesenchymal stem cells induced by interferon-γ and tumor necrosis factor-α

Objective To investigate the mechanism of immunosuppressant FK506 on the immunesuppression of mesenchymal stem cells ( MSCs) induced by interferon ( IFN) -γ and tumor necrosis factor (TNF)-α. Methods MSCs pretreated with inflammatory cytokines were co-cultured with mice spleen cells. After incubation with FK506 for 72 h, proliferation of spleen cells was measured by methyl thiazol tetrazolium (MTT) assay and the apoptosis was assessed by flow cytometry. Real-time polymerase chain reaction (PCR) was used to detect the major molecule that mediated the immunosuppression of MSCs and the effect of FK506 on the molecule. Results MSCs pretreated with inflammatory cytokines could inhibit the proliferation of spleen cells and increase the apoptosis of spleen cells, and the apoptosis rate was (53. 5 ±2. 5) % , which was higher than that of MSCs pretreated with IFN-γ or TNF-α and control group ( P ＜0. 05), and IFN-γ and TNF-α upregulated inducible nitric oxide synthase (iNOS) expression in MSCs significantly, and this immunosuppression could also be antagonized by a specific inhibitor 1400W. However,FK506 could inhibit iNOS expression in MSCs pretreated with IFN-γ and TNF-α, the inhibition of spleen cells proliferation by MSCs was reduced significantly, and the apoptosis rate of spleen cells was reduced to (44. 3 ±3. 2)% (P＜0. 05). Conclusion FK506 inhibits the immunosuppression of MSCs through downregulation of iNOS expression in MSCs pretreated with IFN-γ and TNF-α. Key words: Mesenchymal stem cells; Inflammation; Immunosuppression; FK506