Foxp3 Instability Helps tTregs Distinguish Self and Non-self

Single cell characterization of blood and expanded regulatory T cells in autoimmune polyendocrine syndrome type 1

Immune tolerance fails in autoimmune polyendocrine syndrome type 1 (APS-1) because of AIRE mutations. We have used single cell transcriptomics to characterize regulatory T cells (Tregs) sorted directly from blood and from in vitro expanded Tregs in APS-1 patients compared to healthy controls. We revealed only CD52 and LTB (down) and TXNIP (up) as consistently differentially expressed genes in the datasets. There were furthermore no large differences of the TCR-repertoire of expanded Tregs between the cohorts, but unique patients showed a more restricted use of specific clonotypes. We also found that in vitro expanded Tregs from APS-1 patients had similar suppressive capacity as controls in co-culture assays, despite expanding faster and having more exhausted cells. Our results suggest that APS-1 patients do not have intrinsic defects in their Treg functionality, and that their Tregs can be expanded ex vivo for potential therapeutic applications.

Intricacies of TGF-β signaling in Treg and Th17 cell biology

Balanced immunity is pivotal for health and homeostasis. CD4+ helper T (Th) cells are central to the balance between immune tolerance and immune rejection. Th cells adopt distinct functions to maintain tolerance and clear pathogens. Dysregulation of Th cell function often leads to maladies, including autoimmunity, inflammatory disease, cancer, and infection. Regulatory T (Treg) and Th17 cells are critical Th cell types involved in immune tolerance, homeostasis, pathogenicity, and pathogen clearance. It is therefore critical to understand how Treg and Th17 cells are regulated in health and disease. Cytokines are instrumental in directing Treg and Th17 cell function. The evolutionarily conserved TGF-β (transforming growth factor-β) cytokine superfamily is of particular interest because it is central to the biology of both Treg cells that are predominantly immunosuppressive and Th17 cells that can be proinflammatory, pathogenic, and immune regulatory. How TGF-β superfamily members and their intricate signaling pathways regulate Treg and Th17 cell function is a question that has been intensely investigated for two decades. Here, we introduce the fundamental biology of TGF-β superfamily signaling, Treg cells, and Th17 cells and discuss in detail how the TGF-β superfamily contributes to Treg and Th17 cell biology through complex yet ordered and cooperative signaling networks.

Depletion of enhancer zeste homolog 2 (EZH2) directs transcription factors associated with T cell differentiation through epigenetic regulation of Yin Yang 1(YY1) in combating non-small cell lung cancer (NSCLC)

Non-Small Cell Lung Cancer (NSCLC) is the leading cause of death in all countries alike. In the current study, we have found out that Histone H3Lys4trimethylation is abnormal on YY1 in CD4⁺T Helper (T_H) cells of NSCLC patients which is evident by Histone H3Lys27 trimethylation mediated via EZH2. We investigated the status of Yin Yang 1 (YY1) and the involvement of certain transcription factors that lead to tumorigenesis after depleting endogenous EZH2 in vitro by CRISPR/Cas9 in the CD4⁺T_H1-or-T_H2-polarized cells isolated initially as CD4⁺T_H0 cells from the PBMC of the control subjects and patients suffering from NSCLC. After depletion of endogenous EZH2, RT-qPCR based mRNA expression analysis showed that there was an increase in the expression of T_H1 specific genes and a decrease in the expression of T_H2 specific genes in NSCLC patients CD4⁺T_H cells. We can conclude that this group of NSCLC patients may have the tendency at least in vitro to elucidate adaptive/protective immunity through the depletion of endogenous EZH2 along with the reduction in the expression of YY1. Moreover, depletion of EZH2 not only suppressed the CD4⁺CD25⁺FOXP3⁺Regulatory T cells (Treg) but also it aided the generation of CD8⁺Cytotoxic T Lymphocytes (CTL) which were involved in killing of the NSCLC cells. Thus the transcription factors involved in EZH2 mediated T cell differentiation linked to malignancies offers us an appealing avenue of targeted therapeutic intervention for NSCLC.

Genomic Analysis of Foxp3 Function in Regulatory T Cells

Regulatory T (Treg) cells are critical for tolerance to self-antigens and for preventing autoimmunity. Foxp3 has been identified as a Treg cell lineage-defining transcription factor controlling Treg cell differentiation and function. In this article, we review the current mechanistic and systemic understanding of Foxp3 function enabled by experimental and computational advances in high-throughput genomics.

CD27-Expressing Xenoantigen-Expanded Human Regulatory T Cells Are Efficient in Suppressing Xenogeneic Immune Response

Clinically, xenotransplantation often leads to T-cell-mediated graft rejection. Immunosuppressive agents including polyclonal regulatory T cells (poly-Tregs) promote global immunosuppression, resulting in serious infections and malignancies in patients. Xenoantigen-expanded Tregs (xeno-Tregs) have become a promising immune therapy strategy to protect xenografts with fewer side effects. In this study, we aimed to identify an efficient and stable subset of xeno-Tregs. We enriched CD27⁺ xeno-Tregs using cell sorting and evaluated their suppressive functions and stability in vitro via mixed lymphocyte reaction (MLR), real-time polymerase chain reaction, inflammatory induction assay, and Western blotting. A STAT5 inhibitor was used to investigate the relationship between the function and stability of CD27⁺ xeno-Tregs and the JAK3-STAT5 signaling pathway. A humanized xenotransplanted mouse model was used to evaluate the function of CD27⁺ xeno-Tregs in vivo. Our results show that CD27⁺ xeno-Tregs express higher levels of Foxp3, cytotoxic T-lymphocyte antigen-4 (CTLA4), and Helios and lower levels of interleukin-17 (IL-17) than their CD27^- counterparts. In addition, CD27⁺ xeno-Tregs showed enhanced suppressive function in xeno-MLR at ratios of 1:4 and 1:16 of Tregs:responder cells. Under inflammatory conditions, a lower percentage of CD27⁺ xeno-Tregs secretes IL-17 and interferon-γ (IFN-γ). CD27⁺ xeno-Tregs demonstrated an upregulated JAK3-STAT5 pathway compared with that of CD27^- xeno-Tregs and showed decreased Foxp3, Helios, and CTLA4 expression after addition of STAT5 inhibitor. Mice that received porcine skin grafts showed a normal tissue phenotype and less leukocyte infiltration after reconstitution with CD27⁺ xeno-Tregs. Taken together, these data indicate that CD27⁺ xeno-Tregs may suppress immune responses in a xenoantigen-specific manner, which might be related to the activation of the JAK3-STAT5 signaling pathway.

Advances in research on the effectiveness and mechanism of Traditional Chinese Medicine formulas for colitis-associated colorectal cancer

Inflammatory bowel disease (IBD) can progress into colitis-associated colorectal cancer (CAC) through the inflammation-cancer sequence. Although the mechanism of carcinogenesis in IBD has not been fully elucidated, the existing research indicates that CAC may represent a fundamentally different pathogenesis pattern of colorectal cancer. At present, there is no proven safe and effective medication to prevent IBD cancer. In recent years, Chinese medicine extracts and Chinese medicine monomers have been the subject of numerous articles about the prevention and treatment of CAC, but their clinical application is still relatively limited. Traditional Chinese Medicine (TCM) formulas are widely applied in clinical practice. TCM formulas have demonstrated great potential in the prevention and treatment of CAC in recent years, although there is still a lack of review. Our work aimed to summarize the effects and potential mechanisms of TCM formulas for the prevention and treatment of CAC, point out the issues and limitations of the current research, and provide recommendations for the advancement of CAC research in the future. We discovered that TCM formulas regulated many malignant biological processes, such as inflammation-mediated oxidative stress, apoptosis, tumor microenvironment, and intestinal microecology imbalance in CAC, through a review of the articles published in databases such as PubMed, SCOPUS, Web of Science, Embase, and CNKI. Several major signal transduction pathways, including NF-κB, STAT3, Wnt/β-catenin, HIF-1α, and Nrf2, were engaged. TCM formula may be a promising treatment candidate to control the colitis-cancer transformation, however further high-quality research is required.

Regulation of thymic T regulatory cell differentiation by TECs in health and disease

The thymus produces self-limiting and self-tolerant T cells through the interaction between thymocytes and thymus epithelial cells (TECs), thereby generating central immune tolerance. The TECs are composed of cortical and medullary thymic epithelial cells, which regulate the positive and negative selection of T cells, respectively. During the process of negative selection, thymocytes with self-reactive ability are deleted or differentiated into regulatory T cells (Tregs). Tregs are a subset of suppressor T cells that are important for maintaining immune homeostasis. The differentiation and development of Tregs depend on the development of TECs and other underlying molecular mechanisms. Tregs regulated by thymic epithelial cells are closely related to human health and are significant in autoimmune diseases, thymoma and pregnancy. In this review, we summarize the current molecular and transcriptional regulatory mechanisms by which TECs affect the development and function of thymic Tregs. We also review the pathophysiological models of thymic epithelial cells regulating thymic Tregs in human diseases and specific physiological conditions.

Prebiotic Enriched Exclusive Enteral Nutrition Suppresses Colitis via Gut Microbiome Modulation and Expansion of Anti-inflammatory T Cells in a Mouse Model of Colitis

BACKGROUND & AIMS

Exclusive enteral nutrition (EEN) is used to treat pediatric Crohn's disease (CD), but therapeutic benefits are variable, and EEN can lead to microbial dysbiosis. Because of reported lower efficacy EEN is not routinely used to treat pediatric ulcerative colitis (UC). Inulin-type fructans (IN) beneficially modulate the gut microbiome and promote expansion of anti-inflammatory immune cells. We hypothesized that enriching EEN with IN (EEN IN) would enhance treatment efficacy. To test this, we examined the effects of EEN IN on colitis development, the gut microbiome, and CD4⁺ T cells using an adoptive T-cell transfer model of colitis.

METHODS

TCR-β deficient (^-/-) mice were randomized to 1 of 4 groups: (1) Control, (2) Chow, (3) EEN, and (4) EEN IN, and naive CD4⁺ T cells were adoptively transferred into groups 2-4, after which mice were monitored for 5 weeks before experimental endpoint.

RESULTS

Mice fed EEN IN showed greater colitis protection, with colonic shortening, goblet cell, and crypt density loss reduced compared with EEN fed mice and reduced disease activity and immune cell infiltration compared with chow fed mice, and less crypt hyperplasia and higher survival compared with both groups. EEN IN mice had less deterioration in the colonic mucus layer and had increased levels of Foxp3⁺IL-10⁺ and Rorγt⁺IL-22⁺ and reduced levels of Tbet⁺IFNγ⁺ and Tbet⁺TNF⁺ CD4⁺ T cells. EEN IN also led to higher butyrate concentrations, Bifidobacterium spp. and Anaerostipes caccae relative abundance, and lower [Clostridium] innocuum group spp. and Escherichia-Shigella spp. relative abundance.

CONCLUSIONS

The EEN IN group showed reduced colitis development as compared with the chow and EEN groups. This highlights the potential benefits of EEN IN as a novel induction therapy for pediatric CD and UC patients.

A Role for Folate in Microbiome-Linked Control of Autoimmunity

The microbiome exerts considerable control over immune homeostasis and influences susceptibility to autoimmune and autoinflammatory disease (AD/AID) such as inflammatory bowel disease (IBD), multiple sclerosis (MS), type 1 diabetes (T1D), psoriasis, and uveitis. In part, this is due to direct effects of the microbiome on gastrointestinal (GI) physiology and nutrient transport, but also to indirect effects on immunoregulatory controls, including induction and stabilization of T regulatory cells (T _reg). Secreted bacterial metabolites such as short-chain fatty acids (SCFA) are under intense investigation as mediators of these effects. In contrast, folate (vitamin B9), an essential micronutrient, has attracted less attention, possibly because it exerts global physiological effects which are difficult to differentiate from specific effects on the immune system. Here, we review the role of folate in AD/AID with some emphasis on sight-threatening autoimmune uveitis. Since folate is required for the generation and maintenance of T _{reg ,} we propose that one mechanism for microbiome-based control of AD/AID is via folate-dependent induction of GI tract T _{reg ,} particularly colonic T _reg, via anergic T cells (T _an). Hence, folate supplementation has potential prophylactic and/or therapeutic benefit in AID/AD.

Ectopic FOXP3 Expression in Combination with TGF-β1 and IL-2 Stimulation Generates Limited Suppressive Function in Human Primary Activated Thymocytes Ex Vivo

Regulatory T cells (Tregs), which are characterized by the expression of the transcription factor forkhead box P3 (FOXP3), are the main immune cells that induce tolerance and are regulators of immune homeostasis. Natural Treg cells (nTregs), described as CD4⁺CD25⁺FOXP3⁺, are generated in the thymus via activation and cytokine signaling. Transforming growth factor beta type 1 (TGF-β1) is pivotal to the generation of the nTreg lineage, its maintenance in the thymus, and to generating induced Treg cells (iTregs) in the periphery or in vitro arising from conventional T cells (Tconvs). Here, we tested whether TGF-β1 treatment, associated with interleukin-2 (IL-2) and CD3/CD28 stimulation, could generate functional Treg-like cells from human thymocytes in vitro, as it does from Tconvs. Additionally, we genetically manipulated the cells for ectopic FOXP3 expression, along with the TGF-β1 treatment. We demonstrated that TGF-β1 and ectopic FOXP3, combined with IL-2 and through CD3/CD28 activation, transformed human thymocytes into cells that expressed high levels of Treg-associated markers. However, these cells also presented a lack of homogeneous suppressive function and an unstable proinflammatory cytokine profile. Therefore, thymocyte-derived cells, activated with the same stimuli as Tconvs, were not an appropriate alternative for inducing cells with a Treg-like phenotype and function.

Separating the wheat from the chaff: Making sense of Treg heterogeneity for better adoptive cellular therapy

Regulatory T (Treg) cells are essential for immunological tolerance and can be used to suppress unwanted or excessive immune responses through adoptive cellular therapy. It is increasingly clear that many subsets of Treg cells exist, which have different functions and reside in different locations. Treg cell therapies may benefit from tailoring the selected subset to the tissue that must be protected as well as to characteristics of the immune response that must be suppressed, but little attention is given to this topic in current therapies. Here, we will discuss how three major axes of heterogeneity can be discerned among the Treg cell population, which determine function and lineage fidelity. A first axis relates to the developmental route, as Treg cells can be generated from immature T cells in the thymus or from already mature Tconv cells in the immunological periphery. Heterogeneity furthermore stems from activation history (naïve or effector) and location (lymphoid or peripheral tissues). Each of these axes bestows specific properties on Treg cells, which are further refined by additional processes leading to yet further variation. A critical aspect impacting on Treg cell heterogeneity is TCR specificity, which determines when and where Treg cells are generated as well as where they exhibit their effector functions. We will discuss the implications of this heterogeneity and the role of the TCR for the design of next generation adoptive cellular therapy with Treg cells.

Regulatory T Cell Stability and Plasticity in Atherosclerosis

Regulatory T cells (Tregs) express the lineage-defining transcription factor FoxP3 and play crucial roles in self-tolerance and immune homeostasis. Thymic tTregs are selected based on affinity for self-antigens and are stable under most conditions. Peripheral pTregs differentiate from conventional CD4 T cells under the influence of TGF-β and other cytokines and are less stable. Treg plasticity refers to their ability to inducibly express molecules characteristic of helper CD4 T cell lineages like T-helper (Th)₁, Th₂, Th₁₇ or follicular helper T cells. Plastic Tregs retain FoxP3 and are thought to be specialized regulators for “their” lineage. Unstable Tregs lose FoxP3 and switch to become exTregs, which acquire pro-inflammatory T-helper cell programs. Atherosclerosis with systemic hyperlipidemia, hypercholesterolemia, inflammatory cytokines, and local hypoxia provides an environment that is likely conducive to Tregs switching to exTregs.

Recombinant ling zhi-8 enhances Tregs function to restore glycemic control in streptozocin-induced diabetic rats

OBJECTIVES

To explore the effect of recombinant LZ-8 (rLZ-8) on streptozocin (STZ)-induced diabetic rats and further illustrate its underlying mechanism.

METHODS

Rats were intraperitoneally injected with single-dose STZ 50 mg/kg for induction of type 1 diabetes (T1D), and then, the diabetic rats were treated with rLZ-8 for 3 months. The clinical symptoms, fasting blood glucose, insulin, cytokines, histopathology, flow cytometry and immunofluorescence were used to evaluate the therapeutic effect and underlying mechanism of rLZ-8 on alleviating diabetes mellitus (DM).

KEY FINDINGS

Treatment with rLZ-8 obviously alleviated the clinical symptoms of T1D and dose-dependently reduced the levels of blood glucose, blood lipid and haemoglobin A1c (HbA1c) in diabetic rat model. Meanwhile, rLZ-8 markedly increased insulin secretion and protected against STZ-induced pancreatic tissue injury. Additionally, rLZ-8 dramatically inhibited the levels of TNF-α and IL-1β, and obviously increased the level of IL-10 in serum and pancreas. Further investigation indicated that rLZ-8 treatment significantly increased the number of regulatory T cells (Tregs) and up-regulated the expression of Foxp3 to restore balance between anti-inflammatory and inflammatory cytokines.

CONCLUSIONS

These data suggest that rLZ-8 can antagonize STZ-induced T1D, and its mechanism may be related to inhibit inflammation and enhance Tregs generation.

Nanoengineered targeting strategy for cancer immunotherapy

Cancer immunotherapy is rapidly changing the paradigm of cancer care and treatment by evoking host immunity to kill cancer cells. As clinical approval of checkpoint inhibitors (e.g., ipilimumab and pembrolizumab) has been accelerated by a dramatic improvement of long-term survival in a small subset of patients compared to conventional chemotherapy, growing interesting research has focused on immunotherapy. However, majority of patients have not benefited from checkpoint therapies that only partially remove the inhibition of T cell functions. Insufficient systemic T cell responses, low immunogenicity and the immunosuppressive environment of tumors, create great challenges on therapeutic efficiency. Nanotechnology can integrate multiple functions within controlled size and shape, and has been explored as a unique avenue for the development of cancer immunotherapy. In this review, we mainly address how nanoengineered vaccines can induce robust T cell responses against tumors, as well as how nanomedicine can remodel the tumor immunosuppressive microenvironment to boost antitumor immune responses.

Different Expression Pattern of TIM-3 and Galectin-9 Molecules by Peripheral and Peritoneal Lymphocytes in Women with and without Endometriosis

Endometriosis is a gynecological condition that is associated with chronic pelvic inflammation, pain, and infertility. Although substantial evidence supports that immunological alterations contribute to its pathogenesis and we previously posed a pivotal role of Galectin-9 (Gal-9) in this disorder, the involvement of the TIM-3/Gal-9 pathway in the development of endometriosis-associated immunological abnormalities is not yet known. In the present study, multicolor flow cytometry was used to compare the immunophenotype and cell surface expression of TIM-3 and Gal-9 molecules on peripheral blood (PB) and peritoneal fluid (PF) lymphocytes of women with and without endometriosis. We found an altered distribution of different lymphocyte subpopulations, a markedly decreased TIM-3 labeling on all T and NK subsets and a significantly increased Gal-9 positivity on peripheral CD4+ T and Treg cells of the affected cohort. Furthermore, a significantly increased TIM-3 expression on CD4+T-cells and elevated Gal-9 labeling on all T and NK subsets was also revealed in the PF of the examined patients. In conclusion, our results suggest a persistent activation and disturbed TIM-3/Gal-9-dependent regulatory function in endometriosis, which may be involved in the impaired immune surveillance mechanisms, promotes the survival of ectopic lesions, and aids the evolution of reproductive failures in endometriosis.

Beneficial and Detrimental Effects of Regulatory T Cells in Neurotropic Virus Infections

Neurotropic viruses infect the central nervous system (CNS) and cause acute or chronic neurologic disabilities. Regulatory T cells (Treg) play a critical role for immune homeostasis, but may inhibit pathogen-specific immunity in infectious disorders. The present review summarizes the current knowledge about Treg in human CNS infections and their animal models. Besides dampening pathogen-induced immunopathology, Treg have the ability to facilitate protective responses by supporting effector T cell trafficking to the infection site and the development of resident memory T cells. Moreover, Treg can reduce virus replication by inducing apoptosis of infected macrophages and attenuate neurotoxic astrogliosis and pro-inflammatory microglial responses. By contrast, detrimental effects of Treg are caused by suppression of antiviral immunity, allowing for virus persistence and latency. Opposing disease outcomes following Treg manipulation in different models might be attributed to differences in technique and timing of intervention, infection route, genetic background, and the host’s age. In addition, mouse models of virus-induced demyelination revealed that Treg are able to reduce autoimmunity and immune-mediated CNS damage in a disease phase-dependent manner. Understanding the unique properties of Treg and their complex interplay with effector cells represents a prerequisite for the development of new therapeutic approaches in neurotropic virus infections.