Interleukin-35 mitigates the function of murine transplanted islet cells via regulation of Treg/Th17 ratio

Abstract

Pancreatic islet transplantation is a promising treatment for type 1 diabetes (T1D). Interleukin-35 (IL-35) is a recently discovered cytokine that exhibits potent immunosuppressive functions. However, the role of IL-35 in islet transplant rejection remains to be elucidated. In this study, we isolated islet cells of BALB/c mouse and purified CD4+ T cell subsets of a C57BL/6 mouse. The model for islet transplantation was established in vitro by co-culture of the islet cells and CD4+ T cells. IL-35 (20 ng/ml) was administered every other day. Following co-culture, the islet function and Treg/Th17 ratio were analyzed on days 1, 3, and 5. Furthermore, the Th17/Treg ratio was modulated (1:0–2), and the function of islet cells as well as proliferation of Th17 cells were analyzed. T cell sorting was performed using the magnetic bead sorting method; Treg and Th17 count using flow cytometry; cell proliferation detection using the carboxyfluorescein diacetate succinimidyl ester (CFSE) method, and islet function test using the sugar stimulation test. Results showed that Th17 counts increased in the co-culture system. However, after administration of IL-35, the number of Treg cells increased significantly compared to that in the control group (50.7% of total CD4+ T cells on day 5 in IL-35 group vs. 9.5% in control group) whereas the proliferation rate of Th17 cells was significantly inhibited (0.3% in IL-35 group vs. 7.2% in control group on day 5). Reducing the Th17/Treg ratio significantly improved the function of transplanted islets. Treg inhibited Th17 proliferation and IL-35 enhanced this inhibitory effect. IL-35 mitigates the function of murine transplanted islet cells via regulation of the Treg/Th17 ratio. This might serve as a potential therapeutic strategy for in-vivo islet transplant rejection and T1D.

Rejection of xenogeneic porcine islets in humanized mice is characterized by graft-infiltrating Th17 cells and activated B cells

“…The signature cytokine IFN‐γ has been detected consistently in recipient sera, islet allografts, and in in vitro assays of T cell stimulation . More recently, however, emerging literature suggests a significant role of Th17 responses in allogeneic as well as in xenogeneic islet rejection . Drawing from our previous work using a pig‐to‐B6 mouse islet transplant model in which a predominant Th17 anti‐porcine immune response was identified during acute rejection, we examined if the human Th17 response contributed to xenogeneic porcine islet rejection in our HuMice.…”

Inhibition of cardiac allograft rejection in mice using interleukin‐35‐modified mesenchymal stem cells

“…The most critical ability of IL‐35 its ability to induce the differentiation of CD4 + Foxp3 ‐ Tregs (iTr35), which can once again secrete IL‐35, thus ensuring that IL‐35 maintains a strong immunosuppressive ability and inhibits the effects of multiple effector T cells, such as Th1 and Th17 cells, in vitro and in vivo . More importantly, previous studies on IL‐35 mainly focus on autoimmune diseases, but recent studies show that IL‐35 can effectively alleviate allograft rejection; thus, IL‐35 may become a new potential target for the treatment of allograft rejection …”

“…40 More importantly, previous studies on IL-35 mainly focus on autoimmune diseases, but recent studies show that IL-35 can effectively alleviate allograft rejection; thus, IL-35 may become a new potential target for the treatment of allograft rejection. [9][10][11] Mesenchymal stem cells exhibit multidirectional differentiation potential as well as migration, paracrine, and immunosuppressive activities and have gradually become promising candidates for cell-based immunotherapy. Studies have shown that MSCs can induce the formation of Tregs and inhibit the proliferation of inflammatory Th1 and Th17 cells, 41 exerting significant therapeutic effects on various disease models.…”

“…For example, IL‐35 could inhibit the promotion of T helper 1 (Th1) and Th17 cell differentiation and function, which relieves the symptoms of collagen‐induced arthritis, and accumulating evidence indicates that IL‐35 plays an important role in the occurrence and development of various autoimmune diseases, such as inflammatory bowel disease, multiple sclerosis and systemic lupus erythaematosus . Even more intriguingly, recent studies have shown that IL‐35 could also inhibit graft rejection and thus has great potential in transplantation …”

“…8 Even more intriguingly, recent studies have shown that IL-35 could also inhibit graft rejection and thus has great potential in transplantation. [9][10][11] Mesenchymal stem cells (MSCs), which exhibit the important properties of multilineage differentiation, tissue repair and immunoregulation, 12,13 have recently emerged as promising candidates in gene and cell immunotherapy. Studies indicate that MSCs have strong immunosuppressive effects, which could weaken the immune response of the mixed lymphocyte reaction system in vitro.…”