iPSC-MSCs Combined with Low-Dose Rapamycin Induced Islet Allograft Tolerance Through Suppressing Th1 and Enhancing Regulatory T-Cell Differentiation

Abstract

Mesenchymal stem cell (MSC) differentiation is dramatically reduced after long-term in vitro culture, which limits their application. MSCs derived from induced pluripotent stem cells (iPSCs-MSCs) represent a novel source of MSCs. In this study, we investigated the therapeutic effect of iPSC-MSCs on diabetic mice. Streptozocin-induced diabetic mice transplanted with 400 islets alone or with 1 · 10 6 iPSC-MSCs were examined following rapamycin injection (0.1 mg/kg/day, i.p., from days 0 to 9) after transplantation. Our results showed that iPSC-MSCs combined with rapamycin significantly prolonged islet allograft survival in the diabetic mice; 50% of recipients exhibited long-term survival ( > 100 days). Histopathological analysis revealed that iPSCMSCs combined with rapamycin preserved the graft effectively, inhibited inflammatory cell infiltration, and resulted in substantial release of insulin. Flow cytometry results showed that the proportion of CD4 + and CD8 + T cells was significantly reduced, and the number of T regulatory cells increased in the spleen and lymph nodes in the iPSC-MSCs combined with the rapamycin group compared with the rapamycin-alone group. Production of the Th1 proinflammatory cytokines interleukin-2 (IL-2) and interferon-g was reduced, and secretion of the anti-inflammatory cytokines IL-10 and transforming growth factor-b was enhanced compared with the rapamycin group, as determined using enzyme-linked immunosorbent assays. Transwell separation significantly weakened the immunosuppressive effects of iPSC-MSCs on the proliferation of Con A-treated splenic T cells, which indicated that the combined treatment exerted immunosuppressive effects through cell-cell contact and regulation of cytokine production. Taken together, these findings highlight the potential application of iPSCMSCs in islet transplantation.

Differentiation of Mesenchymal Stem Cells from Human Induced Pluripotent Stem Cells Results in Downregulation of c-Myc and DNA Replication Pathways with Immunomodulation Toward CD4 and CD8 Cells

“…While derivation of ESC‐MSCs was first reported in 2005 and demonstration of immunomodulation has been consistent for this type of PSC‐derived MSCs , studies on iPSC‐MSC immunomodulation have been few and discrepant. The most consistent immunomodulatory findings for iPSC‐MSCs are found in in vivo disease model studies, which demonstrate that these MSCs modulate CD4 T cells toward a Treg phenotype; however, effects on IFN‐γ, a cytokine representing effector Th1, was inconsistent and dependent on the disease model used . In vitro studies showed even less consistent results, with one study demonstrating strong immunomodulation toward natural killer lymphocytes whereas another study did not find any immunomodulatory effects .…”

“…MSCs derived from human ESCs (ESC‐MSCs) were the first to be reported on, and with the exception of one study in which only one cell line was used , nearly all studies have found significant immunomodulatory effects for these MSCs . On the other hand, data on iPSC‐MSC immunomodulation have ranged from immunosuppression to no effect , to immunoreactive . Unlike ESCs, iPSCs can be artificially generated from any somatic cell sources using many methods, but cell‐of‐origin differences can result in alterations in differentiation capacity .…”

Human iPSC-MSC-Derived Xenografts Modulate Immune Responses by Inhibiting the Cleavage of Caspases

“…We previously differentiated iPSCs to MSCs and reported that iPSC‐MSCs, when compared to BM‐MSCs, showed a similar phenotype but longer life span . Transplantation of iPSC‐MSCs not only inhibited both CD4 and CD8 positive T cell subsets , but also expressed less HLA‐II under IFN‐γ stimulation . MSCs isolated from diverse human iPS cell lines can strongly inhibit the cytotoxic functions of NK cells and T helper 2 (Th2) cells mediated allergy .…”

Recombinant IL-33 prolongs leflunomide-mediated graft survival by reducing IFN-γ and expanding CD4+Foxp3+ T cells in concordant heart transplantation

“…1 In concordant models, such as the mouse-to-rat heart transplantation model, the organs undergo cell-mediated rejection when the acute humoral xenograft rejection (AHXR), also known as DXR, is suppressed by sustained treatment with a B-lymphocyte inhibitor. 2 AHXR occurs within 3 days after transplantation in the mouse-to-rat and hamster-to-rat heart transplantation models, characterized by binding of different immunoglobulins (Ig) to the vascular endothelium, vasculitis, thrombosis, tissue destruction, and edema. 3 Turnquist et al 4 observed a potent ability of interleukin (IL)-33 to increase suppressive CD4 + Foxp3 + regulatory T cells (Tregs).…”