Ex Vivo–Induced Bone Marrow-Derived Myeloid Suppressor Cells Prevent Corneal Allograft Rejection in Mice

Abstract

PURPOSE.To investigate the effects of ex vivo-induced bone marrow myeloid-derived suppressor cells (BM-MDSCs) on allogeneic immune responses in corneal transplantation. METHODS.Bone marrow cells from C57BL/6J (B6) mice were cultured with IL-6 and GM-CSF for four days. The ex vivo induction of the BM-MDSCs was assessed using flow cytometry, inducible nitric oxide synthase (iNOS) mRNA expression using reverse transcriptionquantitative polymerase chain reaction, and nitric oxide (NO) production in allogeneic stimulation. T-cell proliferation and regulatory T-cell (Treg) expansion were investigated on allogeneic stimulation in the presence of ex vivo-induced BM-MDSCs. IFN-γ , IL-2, IL-10, and TGF-β1 protein levels were measured using enzyme-linked immunosorbent assays. After subconjunctival injection of ex vivo-induced BM-MDSCs, the migration of the BM-MDSCs into corneal grafts, allogeneic corneal graft survival, neovascularization, and lymphangiogenesis were assessed using flow cytometry, slit-lamp microscopy, and immunohistochemistry. RESULTS. The combination of GM-CSF and IL-6 significantly induced BM-MDSCs with increased iNos mRNA expression. The ex vivo-induced BM-MDSCs promoted NO release in allogeneic stimulation in vitro. The ex vivo-induced BM-MDSCs inhibited T-cell proliferation and promoted Treg expansion. Decreased IFN-γ and increased IL-2, IL-10, and TGF-β1 production was observed in coculture of ex vivo-induced BM-MDSCs. Injected ex vivo-induced BM-MDSCs were confirmed to migrate into the grafts. The injected BM-MDSCs also prolonged corneal graft survival and prevented angiogenesis and lymphangiogenesis. CONCLUSIONS.The ex vivo-induced BM-MDSCs have suppressive effects on allogeneic immune responses and prolong corneal allograft survival via the iNOS pathway, indicating that they may be a potential therapeutic tool for corneal transplantation.

Role of Immune Cell Diversity and Heterogeneity in Corneal Graft Survival: A Systematic Review and Meta-Analysis

“…For example, it has been reported that third-party allogeneic mesenchymal stromal cells could prevent rejection in a pre-sensitized high-risk model of corneal transplantation [134]. Moreover, our previous research has revealed the immunoregulatory effect of donor's bone-marrow-derived suppressor cells in a mouse model of high-risk corneal transplantation [76]. These cellular therapies may provide a potential method of dealing with neovascularization and graft rejection.…”

“…DCs also play an important role in the innate detection of pathogens and activation of the adaptive immune system [75]. Immature DCs (with lower levels of HLA-DR, CD80, CD83, and CD86), including bone-marrow-derived immunosuppressive cells [76], could induce T-cell tolerance, whereas mature DCs induce T-cell immunity [77][78][79][80][81]. Immature DCs were found to be associated with longer allograft survival compared with normal controls during the immune response process of corneal transplantation (Figure 2A) [45].…”

Anti-CD80/86 antibodies inhibit inflammatory reaction and improve graft survival in a high-risk murine corneal transplantation rejection model

“…Inflamed, neovascularized, “high-risk” recipient beds were created 7 , 8 , 45 by placing three intrastromal sutures into the central cornea 14 days before corneal transplantation. As described previously 7 – 9 , 46 , 47 , C57BL/6 corneas were grafted onto BALB/c host beds.…”

“…Graft neovascularization score, opacity score, and survival rate were evaluated using a slit lamp biomicroscope 7 , 45 , 47 . We used a standardized scoring system to calculate the neovascularization (range 0–8) and opacity (range 0–5+) scores.…”

The role of lymphangiogenesis in cardiovascular diseases and heart transplantation

“…For this reason, VEGFR-3 inhibition could be used as lymphatictargeted immunomodulatory therapy to prevent acute and chronic rejection in cardiac allografts [20]. Reduction of lymphangiogenesis has been reported to protect allogenic heart transplants and beyond [19,21]. Therefore, it is important to understand the diversity and complexity of the interplay between lymphangiogenesis and transplantation immunology.…”