IL-35 inhibits acute graft-versus-host disease in a mouse model

The potential therapeutic role of IL-35 in pathophysiological processes in type 1 diabetes mellitus

A chronic autoimmune condition known as type 1 diabetes mellitus (T1DM) has characteristics marked by a gradual immune-mediated deterioration of the β-cells that produce insulin and causes overt hyperglycemia. it affects more than 1.2 million kids and teenagers (0-19 years old). In both, the initiation and elimination phases of T1DM, cytokine-mediated immunity is crucial in controlling inflammation. T regulatory (Treg) cells, a crucial anti-inflammatory CD4+ T cell subset, secretes interleukin-35 (IL-35). The IL-35 has immunomodulatory properties by inhibiting pro-inflammatory cells and cytokines, increasing the secretion of interleukin-10 (IL-10) as well as transforming Growth Factor- β (TGF-β), along with stimulating the Treg and B regulatory (Breg) cells. IL-35, it is a possible target for cutting-edge therapies for cancers, inflammatory, infectious, and autoimmune diseases, including TIDM. Unanswered questions surround IL-35's function in T1DM. Increasing data suggests Treg cells play a crucial role in avoiding autoimmune T1DM. Throughout this review, we will explain the biological impacts of IL-35 and highlight the most recently progresses in the roles of IL-35 in treatment of T1DM; the knowledge gathered from these findings might lead to the development of new T1DM treatments. This review demonstrates the potential of IL-35 as an effective autoimmune diabetes inhibitor and points to its potential therapeutic value in T1DM clinical trials.

LYG1 Deficiency Attenuates the Severity of Acute Graft-Versus-Host Disease via Skewing Allogeneic T Cells Polarization Towards Treg Cells

Acute graft-versus-host disease (aGVHD) is a lethal complication after allogeneic hematopoietic stem cell transplantation. The mechanism involves the recognition of host antigens by donor-derived T cells which induces augmented response of alloreactive T cells. In this study, we characterized the role of a previously identified novel classical secretory protein with antitumor function-LYG1 (Lysozyme G-like 1), in aGVHD. LYG1 deficiency reduced the activation of CD4⁺ T cells and Th1 ratio, but increased Treg ratio in vitro by MLR assay. By using major MHC mismatched aGVHD model, LYG1 deficiency in donor T cells or CD4⁺ T cells attenuated aGVHD severity, inhibited CD4⁺ T cells activation and IFN-γ expression, promoted FoxP3 expression, suppressed CXCL9 and CXCL10 expression, restrained allogeneic CD4⁺ T cells infiltrating in target organs. The function of LYG1 in aGVHD was also confirmed using haploidentical transplant model. Furthermore, administration of recombinant human LYG1 protein intraperitoneally aggravated aGVHD by promoting IFN-γ production and inhibiting FoxP3 expression. The effect of rhLYG1 could partially be abrogated with the absence of IFN-γ. Furthermore, LYG1 deficiency in donor T cells preserved graft-versus-tumor response. In summary, our results indicate LYG1 regulates aGVHD by the alloreactivity of CD4⁺ T cells and the balance of Th1 and Treg differentiation of allogeneic CD4⁺ T cells, targeting LYG1 maybe a novel therapeutic strategy for preventing aGVHD.

STAT4: an immunoregulator contributing to diverse human diseases

Signal transducer and activator of transcription 4 (STAT4) is a member of the STAT family and localizes to the cytoplasm. STAT4 is phosphorylated after a variety of cytokines bind to the membrane, and then dimerized STAT4 translocates to the nucleus to regulate gene expression. We reviewed the essential role played by STAT4 in a wide variety of cells and the pathogenesis of diverse human diseases, especially many kinds of autoimmune and inflammatory diseases, via activation by different cytokines through the Janus kinase (JAK)-STAT signaling pathway.

Interleukin (IL)-35 Suppresses IL-6 and IL-8 Production in IL-17A-Stimulated Human Periodontal Ligament Cells

Interleukin (IL)-35 is a novel anti-inflammatory cytokine that is produced by regulatory T cells. IL-35 is reported to suppress IL-17A-producing helper T (Th17) cell activation. IL-17A is related to progression of periodontitis. Furthermore, IL-35 and IL-17A are detected in human gingival crevicular fluid. However, the effect of IL-35 and interaction between IL-35 and IL-17A on pro-inflammatory cytokine production in human periodontal resident cells are still unclear. The aim of this study was to clarify the effect of IL-35 on IL-6 and IL-8 production in human periodontal ligament cells (HPDLCs) stimulated with IL-17A. IL-35 inhibited IL-6 and IL-8 production in IL-17A-stimulated HPDLCs. Moreover, western blot analysis showed that IL-35 suppressed extracellular signal-regulated kinase (ERK) and nuclear factor (NF)-κB p65 phosphorylation in IL-17A-stimulated HPDLCs. Our findings suggested that IL-35 produced from regulatory T cells might inhibit progression of periodontitis by decreasing IL-17A-induced levels of IL-6 and IL-8.

The Role of Co-stimulatory/Co-inhibitory Signals in Graft-vs.-Host Disease

Allogeneic hematopoietic cell transplantation (allo-HCT) is an effective immunotherapeutic approach for various hematologic and immunologic ailments. Despite the beneficial impact of allo-HCT, its adverse effects cause severe health concerns. After transplantation, recognition of host cells as foreign entities by donor T cells induces graft-vs.-host disease (GVHD). Activation, proliferation and trafficking of donor T cells to target organs and tissues are critical steps in the pathogenesis of GVHD. T cell activation is a synergistic process of T cell receptor (TCR) recognition of major histocompatibility complex (MHC)-anchored antigen and co-stimulatory/co-inhibitory signaling in the presence of cytokines. Most of the currently used therapeutic regimens for GVHD are based on inhibiting the allogeneic T cell response or T-cell depletion (TCD). However, the immunosuppressive drugs and TCD hamper the therapeutic potential of allo-HCT, resulting in attenuated graft-vs.-leukemia (GVL) effect as well as increased vulnerability to infection. In view of the drawback of overbroad immunosuppression, co-stimulatory, and co-inhibitory molecules are plausible targets for selective modulation of T cell activation and function that can improve the effectiveness of allo-HCT. Therefore, this review collates existing knowledge of T cell co-stimulation and co-inhibition with current research that may have the potential to provide novel approaches to cure GVHD without sacrificing the beneficial effects of allo-HCT.

Interleukin 35 induced Th2 and Tregs bias under normal conditions in mice

Objective

The benefits of IL-35 treatment have been verified in multiple animal models of diseases, while its influence on T cells immunity under normal condition still needs to be elucidated. The present study was designed to investigate the effects modulating IL-35 levels in vivo and in vitro on T cells, response and also the effects on T cells subsets in normal mice.

Methods

A plasmid pMSCV-IL-35-GFP carrying mouse linear IL-35 fragment with two subunits joint together was constructed and the heterodimer expression was confirmed. Normal mice were randomly divided into three groups and received an intravenous injection of PBS, pMSCV-GFP and pMSCV-IL-35-GFP respectively. After 72 h, spleen tissues and peripheral blood were harvested for following analysis. Meanwhile, splenic T cells were isolated and incubated with 10, 30, or 50 ng/mL recombinant IL-35 factor for 24 h with the addition of anti-CD3/CD28 in vitro. T-cell subsets were assessed by Fluorescence activated cell sorting (FACS) and related cytokines together with effector molecules were determined by real time PCR.

Results

Western blotting confirmed a 52 kDa band in the cell lysate of HEK 293T transducted with pMSCV-IL-35-GFP plasmid, indicating a successful expression of IL-35. Ebi3 and IL-12A, two subunits of IL-35, could be identified 72 h post DNA injection. IL-35 upregulation in vivo effectively inhibit CD4⁺ and CD8⁺ T cell proliferation and Th1 cytokine secretion. Effector molecules of CD8⁺ T cells were also remarkably suppressed. On the contrary, high level of IL-35 significantly induced CD4⁺ CD25⁺ Tregs and Th2 enhancement. The in vitro study provided similar results.

Conclusion

The results indicated Th1 and CD8⁺ T cell inhibition and Th2 and Tregs bias in the presence of IL-35 under a normal state which partly contributed to its therapeutic potential.

Genetic Association of Hematopoietic Stem Cell Transplantation Outcome beyond Histocompatibility Genes

The outcome of hematopoietic stem cell transplantation (HSCT) is controlled by genetic factors among which the leukocyte antigen human leukocyte antigen (HLA) matching is most important. In addition, minor histocompatibility antigens and non-HLA gene polymorphisms in genes controlling immune responses are known to contribute to the risks associated with HSCT. Besides single-nucleotide polymorphisms (SNPs) in protein coding genes, SNPs in regulatory elements such as microRNAs (miRNAs) contribute to these genetic risks. However, genetic risks require for their realization the expression of the respective gene or miRNA. Thus, gene and miRNA expression studies may help to identify genes and SNPs that indeed affect the outcome of HSCT. In this review, we summarize gene expression profiling studies that were performed in recent years in both patients and animal models to identify genes regulated during HSCT. We discuss SNP–mRNA–miRNA regulatory networks and their contribution to the risks associated with HSCT in specific examples, including forkheadbox protein 3 and regulatory T cells, the role of the miR-155 and miR-146a regulatory network for graft-versus-host disease, and the function of MICA and its receptor NKG2D for the outcome of HSCT. These examples demonstrate how SNPs affect expression or function of proteins that modulate the alloimmune response and influence the outcome of HSCT. Specific miRNAs targeting these genes and directly affecting expression of mRNAs are identified. It might be valuable in the future to determine SNPs and to analyze miRNA and mRNA expression in parallel in cohorts of HSCT patients to further elucidate genetic risks of HSCT.

β-cell-specific IL-35 therapy suppresses ongoing autoimmune diabetes in NOD mice

IL-35 is a recently identified cytokine exhibiting potent immunosuppressive properties. The therapeutic potential and effects of IL-35 on pathogenic T effector cells (Teff) and Foxp3⁺ Treg, however, are ill defined. We tested the capacity of IL-35 to suppress ongoing autoimmunity in NOD mice. For this purpose, an adeno-associated virus vector in which IL-35 transgene expression is selectively targeted to β cells via an insulin promoter (AAV8mIP-IL35) was used. AAV8mIP-IL35 vaccination of NOD mice at a late preclinical stage of type 1 diabetes (T1D) suppressed β-cell autoimmunity and prevented diabetes onset. Numbers of islet-resident conventional CD4⁺ and CD8⁺ T cells, and DCs were reduced within 4 weeks of AAV8mIP-IL35 treatment. The diminished islet T-cell pool correlated with suppressed proliferation, and a decreased frequency of IFN-γ-expressing Teff. Ectopic IL-35 also reduced islet Foxp3⁺ Treg numbers and proliferation, and protection was independent of induction/expansion of adaptive islet immunoregulatory T cells. These findings demonstrate that IL-35-mediated suppression is sufficiently robust to block established β-cell autoimmunity, and support the use of IL-35 to treat T1D and other T-cell-mediated autoimmune diseases.