Induced pluripotent stem cells-derived suppressor cells ameliorate experimental autoimmune uveoretinitis in mice

Abstract

Purpose : Induced pluripotent stem cells-derived suppressor cells (iPS-SCs) have been known to have immunosuppressive ability in mice. In this study, we evaluate the efficacy of iPS-SCs in experimental autoimmune uveoretinitis (EAU) in mice.

Methods : iPS cells were established from spleen B cells isolated from naïve C57BL/6 mice, then they were stimulated with cytokines (e.g. macrophage-colony-stimulating factor, granulocyte macrophage-colony- stimulating factor and interleukin-4) and lipopolysaccharide to be differentiated into iPS-SCs. Mice received iPS-SCs intraperitoneally 24 hours before EAU induction.To induce EAU, mice were immunized with human interphotoreceptor-binding protein derived peptide 1-20 emulsified with complete Freund’s adjuvant, and purified Bordetella pertussis toxin was injected intraperitoneally as an additional adjuvant. Clinical severity of EAU was assessed every 3 or 4 days. Eyes were enucleated 21 days after immunization to evaluate the histopathological severity. T cell proliferative response was examined in vitro. CD4⁺T cells were enriched from draining lymph nodes of immunized mice at day 9, and labeled with division-tracking dye (CellTrace™ Violet). After co-cultured with irradiated syngeneic spleen cells and antigens with or without iPS-SCs, proliferation of T cells was evaluated. Cytokine levels of tumor necrosis factor-α (TNF-α) and interferon-gamma (IFN-γ) were also quantified in culture supernatant.

Results : EAU was significantly milder on day 21 in iPS-SCs treated group (2.5 ± 0.5) than controls (1.6 ± 0.5, p < 0.05) clinically. Histologic score was lower in treated mice than in controls. T cell proliferative response was suppressed in the presence of iPS-SCs (17.6 ± 1.1%) compared with the controls (37.5 ± 0.6%, p < 0.01). The level of nitric oxide was significantly elevated when cultured with iPS-SCs (32.5 ± 4.5 μM) than controls (0.2 ± 0.2 μM, p < 0.01). In contrast, concentrations of TNF-α (iPS-SCs: 55.4 ± 3.2 pg/ml, control: 91.7 ± 2.5 pg/ml) and IFN-γ(iPS-SCs: 2508.7 ± 64.1 pg/ml, control: 4739.5 ± 117.5 pg/ml) were significantly decreased in the presence of iPS-SCs compared with the controls (p < 0.01).

Conclusions : The results of the present study indicated the possibility of the new “immunotherapy approach” to uveitis.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.