TREG-cell therapies for autoimmune rheumatic diseases

Chimeric antigen receptor T cell therapy for autoimmune disease

Infusion of T cells engineered to express chimeric antigen receptors (CARs) that target B cells has proven to be a successful treatment for B cell malignancies. This success inspired the development of CAR T cells to selectively deplete or modulate the aberrant immune responses that underlie autoimmune disease. Promising results are emerging from clinical trials of CAR T cells targeting the B cell protein CD19 in patients with B cell-driven autoimmune diseases. Further approaches are being designed to extend the application and improve safety of CAR T cell therapy in the setting of autoimmunity, including the use of chimeric autoantibody receptors to selectively deplete autoantigen-specific B cells and the use of regulatory T cells engineered to express antigen-specific CARs for targeted immune modulation. Here, we highlight important considerations, such as optimal target cell populations, CAR construct design, acceptable toxicities and potential for lasting immune reset, that will inform the eventual safe adoption of CAR T cell therapy for the treatment of autoimmune diseases.

Exploring the therapeutic potential of regulatory T cell in rheumatoid arthritis: Insights into subsets, markers, and signaling pathways

Rheumatoid arthritis (RA) is a complex autoimmune inflammatory rheumatic disease characterized by an imbalance between immunological reactivity and immune tolerance. Regulatory T cells (Tregs), which play a crucial role in controlling ongoing autoimmunity and maintaining peripheral tolerance, have shown great potential for the treatment of autoimmune inflammatory rheumatic diseases such as RA. This review aims to provide an updated summary of the latest insights into Treg-targeting techniques in RA. We focus on current therapeutic strategies for targeting Tregs based on discussing their subsets, surface markers, suppressive function, and signaling pathways in RA.

Insufficient phosphorylation of STAT5 in Tregs inhibits the expression of BLIMP-1 but not IRF4, reduction the proportion of Tregs in pediatric aplastic anemia

Deficiency in regulatory T cells (Tregs) is an important mechanism underlying the pathogenesis of pediatric aplastic anemia, but its specific mechanism is unclear. In our study, we aimed to investigate whether IL-2/STAT5 can regulate the proliferation of Tregs in aplastic anemia (AA) by regulating their expression of B lymphocyte-induced mature protein-1 (BLIMP-1) or interferon regulatory factor 4 (IRF4). Through clinical research and animal experiments, we found that poor activation of the IL-2/STAT5 signaling pathway may leads to low expression of BLIMP-1 in Tregs of children with AA, which leads to defects in the differentiation and proliferation of Tregs in AA. In AA model mice, treatment with IL-2c reversed the decrease in Treg proportions and reduction in Blimp-1 expression in Tregs by increasing the phosphorylation of Stat5 in Tregs. In AA, deficiency of IRF4 expression in Tregs is closely related to the deficiency of Tregs, but is not regulated by the IL-2/STAT5 pathway.

Current status of immunological therapies for rheumatoid arthritis with a focus on antigen-specific therapeutic vaccines

Rheumatoid arthritis (RA) is recognized as an autoimmune joint disease driven by T cell responses to self (or modified self or microbial mimic) antigens that trigger and aggravate the inflammatory condition. Newer treatments of RA employ monoclonal antibodies or recombinant receptors against cytokines or immune cell receptors as well as small-molecule Janus kinase (JAK) inhibitors to systemically ablate the cytokine or cellular responses that fuel inflammation. Unlike these treatments, a therapeutic vaccine, such as CEL-4000, helps balance adaptive immune homeostasis by promoting antigen-specific regulatory rather than inflammatory responses, and hence modulates the immunopathological course of RA. In this review, we discuss the current and proposed therapeutic products for RA, with an emphasis on antigen-specific therapeutic vaccine approaches to the treatment of the disease. As an example, we describe published results of the beneficial effects of CEL-4000 vaccine on animal models of RA. We also make a recommendation for the design of appropriate clinical studies for these newest therapeutic approaches, using the CEL-4000 vaccine as an example. Unlike vaccines that create or boost a new immune response, the clinical success of an immunomodulatory therapeutic vaccine for RA lies in its ability to redirect autoreactive pro-inflammatory memory T cells towards rebalancing the "runaway" immune/inflammatory responses that characterize the disease. Human trials of such a therapy will require alternative approaches in clinical trial design and implementation for determining safety, toxicity, and efficacy. These approaches include adaptive design (such as the Bayesian optimal design (BOIN), currently employed in oncological clinical studies), and the use of disease-related biomarkers as indicators of treatment success.

Off-label use of Baricitinib improves moderate and severe atopic dermatitis in China through inhibiting MAPK and PI3K/Akt/mTOR pathway via targeting JAK-STAT signaling of CD4+ cells

As an inflammatory disease with a disrupted immune system, cytokine disorders in atopic dermatitis (AD) are closely related to the abnormal activation of JAK-STAT signal pathway. The critical relevance of the JAK-STAT signaling pathway to the pathogenesis of AD provides a strong rationale for JAK inhibitor research. Baricitinib, a small-molecule oral JAK inhibitor, has been proven to inhibit JAK-STAT signaling in a variety of diseases, including AD. It is currently available in China for off-label use. However, its efficacy in China and its mechanism are rarely reported. In our study, we found that the immune status of patients with moderate and severe AD was hyperactive. Among the 49 known immunotherapy targets, JAK1 and JAK2 genes on lymphocytes of AD patients were significantly upregulated, which was closely related to the symptom severity in moderate and severe AD patients. Baricitinib can improve immune hyperresponsiveness and clinical symptoms in moderate and severe AD by inhibiting the activation of Th2 cell subsets and the secretion of Th2-type cytokines through MAPK, mTOR and PI3K-Akt signaling pathways, providing an important theoretical basis for clinical off-label use of Baricitinib to treat moderate and severe AD.

Unravelling the role of Sildenafil and SB204741 in suppressing fibrotic potential of peritoneal fibroblasts obtained from PD patients

Introduction: Peritoneal fibrosis (PF) results in technique failure in peritoneal dialysis (PD) patients. Peritoneal fibroblasts are characterized by increase in the ACTA2 gene, responsible for alpha smooth muscle actin (α-SΜΑ), extracellular matrix (ECM) production, and inflammatory cytokines production, which are the are key mediators in the pathogenesis of PF. 5-hydroxytryptamine (5-HT; serotonin) induces ECM synthesis in fibroblasts in a transforming growth factor-beta 1 (TGF-β1) dependent manner. The purpose of our study was to identify the potential mechanism and role of sildenafil and 5HT2B receptor inhibitor (SB204741) combination in attenuating PD-associated peritoneal fibrosis. Methods: Studies were performed to determine the effect of TGF-β1, sildenafil, and SB204741 on human peritoneal fibroblasts (HPFBs) isolated from the parietal peritoneum of patients in long-term PD patients (n = 6) and controls (n = 6). HPFBs were incubated with TGF-β1 (10 ng/mL) for 1 h and later with TGF-β1 (10 ng/mL)/[sildenafil (10 µM) or SB204741 (1 µM)] and their combination for 24 h (post-treatment strategy). In the pre-treatment strategy, HPFBs were pre-treated with sildenafil (10 µM) or SB204741 (1 µM) and a combination of the two for 1 h and later with only TGF-β1 (10 ng/mL) for 24 h. Results: The anti-fibrotic effects of the combination of sildenafil and SB204741 were greater than that of each drug alone. In TGF-β1-stimulated HPFBs, pro-fibrotic genes (COL1A1, COL1A2, ACTA2, CTGF, FN1, and TGFB1) exhibited higher expression than in controls, which are crucial targets of sildenafil and SB204741 against peritoneal fibrosis. The synergistic approach played an anti-fibrotic role by regulating the pro- and anti-fibrotic gene responses as well as inflammatory cytokine responses. The combination treatment significantly attenuated peritoneal fibrosis, as evident by the almost complete amelioration of ACTA2 expression, restoration of anti-fibrotic genes (MMP2/TIMP1), and, at least, by reducing the expression of pro-inflammatory cytokines (IFN-γ, IL-4, IL-17, IL-1β, IL-6, TNF-α, and TGF-β1) along with an increase in IL-10 levels. Discussion: Taken together, the above research evidences that the combination of sildenafil and SB204741 may have therapeutic potential in suppressing peritoneal fibrosis due to peritoneal dialysis.

Augmenting regulatory T cells: new therapeutic strategy for rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune condition marked by inflammation of the joints, degradation of the articular cartilage, and bone resorption. Recent studies found the absolute and relative decreases in circulating regulatory T cells (Tregs) in RA patients. Tregs are a unique type of cells exhibiting immunosuppressive functions, known for expressing the Foxp3 gene. They are instrumental in maintaining immunological tolerance and preventing autoimmunity. Increasing the absolute number and/or enhancing the function of Tregs are effective strategies for treating RA. This article reviews the studies on the mechanisms and targeted therapies related to Tregs in RA, with a view to provide better ideas for the treatment of RA.

mRNA Lipid Nanoparticles for Ex Vivo Engineering of Immunosuppressive T Cells for Autoimmunity Therapies

Cell-based therapies for autoimmune diseases have gained significant traction, with several approaches centered around the regulatory T (Treg) cell─a well-known immunosuppressive cell characterized by its expression of the transcription factor Foxp3. Unfortunately, due to low numbers of Treg cells available in circulation, harvesting and culturing Treg cells remains a challenge. It has been reported that engineering Foxp3 expression in CD4+ T cells can result in a Treg-like phenotype; however, current methods result in the inefficient engineering of these cells. Here, we develop an ionizable lipid nanoparticle (LNP) platform to effectively deliver Foxp3 mRNA to CD4+ T cells. We successfully engineer CD4+ T cells into Foxp3-T (FP3T) cells that transiently exhibit an immunosuppressive phenotype and functionally suppress the proliferation of effector T cells. These results demonstrate the promise of an LNP platform for engineering immunosuppressive T cells with potential applications in autoimmunity therapies.

Research progress on Limosilactibacilus reuteri in diseases

Limosilactibacilus reuteri (L. reuteri) is a gram-positive probiotic that does not produce peroxidase. Certain strains of L. reuteri have been approved for use in human health products in China. The probiotic mechanism of L. reuteri in organisms can be divided into two directions: first, L. reuteri directly regulates the gut microbiota and indirectly affecting the host; second, L. reuteri secretes substances that directly affect the host. Numerous studies have shown that a deficiency in this commensal bacterium is associated with various diseases in different systems (such as inflammation in the digestive system, systemic lupus erythematosus in the autoimmune system, metabolic syndrome in the endocrine system, and mastitis in the reproductive system). However, although recent studies have found that L. reuteri can also promote disease progression, but overall, it is more beneficial than harmful in general. Further, more in-depth experiments are needed to determine whether L. reuteri should be removed from probiotics in the future. In this review, we provide an overview of the research history of L. reuteri and conclude with the main mechanisms through which this intestinal symbiont can improve health or aggravate diseases.

FGL1-LAG3 axis impairs IL-10-Producing regulatory T cells associated with Systemic lupus erythematosus disease activity

Background

Systemic Lupus Erythematosus (SLE) is a prototypic autoimmune disease, which is accompanied by liver damage. However, it remains unknown whether liver damage is associated with SLE progression.

Method

ology: HepG2 and L-02 cells were stimulated with cytokines, and FGL1 mRNA and protein expression levels were determined using Real-time PCR and ELISA, respectively. Regulatory T cells (Treg) isolated from healthy individuals as well as patients with SLE and SLE and liver damage (SLE-LD) were cultured with autologous effector CD4+T cells in the presence of a functional antibody or isotype control. The expression levels of LAG3, CD25, PD-1, CXCR5, ICOS and OX40 were evaluated by flow cytometry. FGL1, IL-10, IL-17a and IL-21 levels in serum or culture supernatants were quantified by ELISA.

Results

Patients with SLE-LD exhibits higher disease activity indices and anti-dsDNA antibody levels. Importantly, fibrinogen-like protein 1 (FGL1), a key factor released from the injured liver, is up-regulated in patients with SLE-LD and is associated with disease activity. FGL1 expression is induced by the inflammatory cytokine IL-6 signaling in hepatocytes. Higher expression of the FGL1 receptor lymphocyte activation gene 3 (LAG3) is detected in Treg cells from patients with SLE-LD. The FGL1-LAG3 signaling axis inhibits Treg cell proliferation and impairs the suppressive activity of Treg cells by limiting IL-10 secretion. Furthermore, FGL1-LAG3 signaling promotes the production of pathogenic IL-17a and IL-21 by CD4+T cells by reducing IL-10 level produced by Treg in patients with SLE.

Conclusions

The FGL1-LAG3 signal axis is a key mechanism that subverts the suppressive function of Treg cells. This may provide a new therapeutic target for SLE and SLE-induced liver damage.

Mechanisms regulating the loss of Tregs in HUPO mice that develop spontaneous inflammatory arthritis

T regulatory cells (Tregs) are a potential therapeutic target in many autoimmune diseases including rheumatoid arthritis (RA). The mechanisms responsible for the maintenance of Tregs in chronic inflammatory conditions such as RA are poorly understood. We employed our mouse model of RA in which, the following deletion of Flice-like inhibitory protein in CD11c+ cells, CD11c-FLIP-KO (HUPO) mice develop spontaneous, progressive, erosive arthritis, with reduced Tregs, and the adoptive transfer of Tregs ameliorates the arthritis. HUPO thymic Treg development was normal, but peripheral of Treg Foxp3 was diminished mediated by reduction of dendritic cells and interleukin-2 (IL-2). During chronic inflammatory arthritis Tregs fail to maintain Foxp3, leading to non-apoptotic cell death and conversion to CD4+CD25+Foxp3- cells. Treatment with IL-2 increased Tregs and ameliorated the arthritis. In summary, reduced dendritic cells and IL-2 in the milieu of chronic inflammation, contribute to Treg instability, promoting HUPO arthritis progression, and suggesting a therapeutic approach in RA.

Regulatory T cells in peripheral tissue tolerance and diseases

Maintenance of peripheral tolerance by CD4+Foxp3+ regulatory T cells (Tregs) is essential for regulating autoreactive T cells. The loss of function of Foxp3 leads to autoimmune disease in both animals and humans. An example is the rare, X-linked recessive disorder known as IPEX (Immune Dysregulation, Polyendocrinopathy, Enteropathy X-linked) syndrome. In more common human autoimmune diseases, defects in Treg function are accompanied with aberrant effector cytokines such as IFNγ. It has recently become appreciated that Tregs plays an important role in not only maintaining immune homeostasis but also in establishing the tissue microenvironment and homeostasis of non-lymphoid tissues. Tissue resident Tregs show profiles that are unique to their local environments which are composed of both immune and non-immune cells. Core tissue-residence gene signatures are shared across different tissue Tregs and are crucial to homeostatic regulation and maintaining the tissue Treg pool in a steady state. Through interaction with immunocytes and non-immunocytes, tissue Tregs exert a suppressive function via conventional ways involving contact dependent and independent processes. In addition, tissue resident Tregs communicate with other tissue resident cells which allows Tregs to adopt to their local microenvironment. These bidirectional interactions are dependent on the specific tissue environment. Here, we summarize the recent advancements of tissue Treg studies in both human and mice, and discuss the molecular mechanisms that maintain tissue homeostasis and prevent pathogenesis.

Immunomodulatory Mechanism and Potential Application of Dental Pulp-Derived Stem Cells in Immune-Mediated Diseases

Dental pulp stem cells (DPSCs) are mesenchymal stem cells (MSCs) derived from dental pulp tissue, which have high self-renewal ability and multi-lineage differentiation potential. With the discovery of the immunoregulatory ability of stem cells, DPSCs have attracted much attention because they have similar or even better immunomodulatory effects than MSCs from other sources. DPSCs and their exosomes can exert an immunomodulatory ability by acting on target immune cells to regulate cytokines. DPSCs can also migrate to the lesion site to differentiate into target cells to repair the injured tissue, and play an important role in tissue regeneration. The aim of this review is to summarize the molecular mechanism and target cells of the immunomodulatory effects of DPSCs, and the latest advances in preclinical research in the treatment of various immune-mediated diseases, providing new reflections for their clinical application. DPSCs may be a promising source of stem cells for the treatment of immune-mediated diseases.

Mitochondrial fusion induced by transforming growth factor-β1 serves as a switch that governs the metabolic reprogramming during differentiation of regulatory T cells

Although metabolic reprogramming during the differentiation of regulatory T cells (Treg cells) has been extensively studied, the molecular switch to alter energy metabolism remains undefined. The present study explores the critical role of mitochondrial dynamics in the reprogramming and consequent generation of Treg cells. The results showed that during Treg cell differentiation, mitochondrial fusion but not fission led to elevation of oxygen consumption rate values, facilitation of metabolic reprogramming, and increase of number of Treg cells and expression of Foxp3 in vitro and in vivo. Mechanistically, mitochondrial fusion favored fatty acid oxidation but restricted glycolysis in Treg cells through down-regulating the expression of HIF-1α. Transforming growth factor-β1 (TGF-β1) played a crucial role in the induction of mitochondrial fusion, which activated Smad2/3, promoted the expression of PGC-1α and therefore facilitated the expression of mitochondrial fusion proteins. In conclusion, during Treg cell differentiation, TGF-β1 promotes PGC-1α-mediated mitochondrial fusion, which drives metabolic reprogramming from glycolysis to fatty acid oxidation via suppressing HIF-1α expression, and therefore favors the generation of Treg cells. The signals and proteins involved in mitochondrial fusion are potential therapeutic targets for Treg cell-related diseases.

Reduced circulating Tregs and positive pANCA were robustly associated with the occurrence of antiphospholipid syndrome in patients with systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is a typical chronic immune disorder with clinical heterogeneity. The systemic abnormal immune response not only challenges the diagnosis and treatment of the disease itself but also the secondary antiphospholipid syndrome (APS), characterized by recurrent arterial or venous thrombosis, recurrent spontaneous abortion, or stillbirth. Clinical interest has primarily focused on primary APS's pathological and clinical features. However, differences in clinical features and laboratory indicators between SLE with or without APS are still lacking, especially differences between circulating lymphocytes, which are critical in the pathogenesis of SLE and its complications.

METHODS

In this retrospective study, we collected and analyzed clinical characteristics, general laboratory indicators, immunological indicators, and circulating lymphocyte subsets of SLE with or without APS.

RESULTS

Systemic lupus erythematosus with APS (SLE-APS) had elevated SLEDAI scores, hospitalization costs and time, and frequencies of central nervous system symptoms and spontaneous abortion compared with those without APS. SLE-APS had higher positive anti-Cardiolipin antibodies, anti-β2 Glycoprotein 1 antibodies, and perinuclear antineutrophil cytoplasmic antibody (pANCA) than none-APS patients. Compared with healthy controls (HCs), the circulating lymphocyte subsets were altered to some extent in all patients, especially in patients with SLE-APS. Reduced Tregs and positive pANCA were independent risk factors for SLE secondary APS.

CONCLUSION

The present study revealed a robust association between APS secondary to SLE and reduced Tregs and positive pANCA, which provides essential information regarding the diagnosis and therapeutic possibilities of APS secondary to SLE.

A disposable impedance-based sensor for in-line cell growth monitoring in CAR-T cell manufacturing

This paper presents the development of low-cost, disposable impedance-based sensors for real-time, in-line monitoring of suspension cell culture. The sensors consist of electrical discharge machining (EDM) cut aluminum electrodes and polydimethylsiloxane (PDMS) spacers, both of which are low-cost materials that can be safely disposed of. Our research demonstrates the capability of these low-cost sensors for in-line, non-invasive monitoring of suspension cell growth in cell manufacturing. We use a hybrid equivalent circuit model to extract key features/parameters from intertwined impedance signals, which are then fed to a novel physics-inspired (gray-box) model designed for α-relaxation. This model determines viable cell count (VCC), a critical quality attribute (CQA) in cell manufacturing. Predicted VCC trends are then compared with image-based cell count data to verify their accuracy.

AhR activation promotes Treg cell generation by enhancing Lkb1-mediated fatty acid oxidation via the Skp2/K63-ubiquitination pathway

Several aryl hydrocarbon receptor (AhR) agonists have been reported to promote the generation of regulatory T cells (Treg cells), and the action mechanisms need to be identified. In this study, we addressed the underlying mechanism of AhR activation to induce the generation of Treg cells in the view of cellular metabolism. Naïve CD4+ T cells were purified with mouse CD4+ CD62L+ T Cells Isolation Kits. The proportions of Treg cells were detected by flow cytometry. The value of oxygen consumption rate (OCR) of CD4+ T cells was detected by the Seahorse XFe 96 analyzer. The activation of fatty acid oxidation (FAO)-related metabolic pathways was detected by Western blotting. Intracellular localization of Lkb1 was detected by immunofluorescence. The Strad-Mo25-Lkb1 complex formation and K63 chain ubiquitination modification of Lkb1 were detected by co-immunoprecipitation. The binding of AhR to the Skp2 promoter was detected by constructing luciferase reporter gene. AhR or carnitine palmitoyltransferases 1 was knockdown in dextran sulphate sodium (DSS)-induced colitis or collagen-induced arthritis (CIA) mice by infecting mice with adeno-associated virus via the tail vein injection. Compared to the control group, exogenous and endogenous AhR agonists 3,3'-diindolylmethane (DIM) and 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) were shown to preferentially upregulate the mRNA expression of FAO-related enzymes and the value of OCR. Consistently, pharmacological or genetic inhibition of FAO markedly diminished the induction of DIM and ITE on the differentiation of Treg cells. DIM and ITE functioned mainly through activating the liver kinase B1 (Lkb1)-AMPK pathway via promotion of Lkb1-Strad-Mo25 complex formation and Lkb1 K63 ubiquitination. DIM and ITE were also shown to upregulate the mRNA expression of Skp2, a ubiquitination-related enzyme, and facilitate the binding of AhR to the xenobiotic responsive element of Skp2 promoter region by luciferase reporter gene assay. Furthermore, the contribution of Skp2/K63 ubiquitination/Lkb1/FAO axis was verified in (DSS)-induced colitis or CIA mice. In summary, these findings indicate that AhR activation promotes Treg cell generation by enhancing Lkb1-mediated FAO via the Skp2/K63-ubiquitination pathway, and AhR agonists may be used as inducers of Treg cells to prevent and treat autoimmune diseases.

Prednisone acetate modulates Th1/Th2 and Th17/Treg cell homeostasis in experimental autoimmune uveitis via orchestrating the Notch signaling pathway

Uveitis is an immune eye disease that can seriously impair vision. Glucocorticoids (GC_S) have been extensively used to treat uveitis, though the mechanisms have not been fully elucidated. In this study, we investigated the regulatory effects of prednisone acetate (PA) on the Th1/Th2 and Th17/Treg balance in experimental autoimmune uveitis (EAU) through modulating the Notch signaling pathway. Briefly, Lewis rats were randomly divided into the normal control (NC), EAU, and EAU + PA groups. Rats in EAU and EAU + PA groups were induced EAU, while those in the EAU + PA group were treated with PA. Clinical and histopathological scores were employed to assess the progression of EAU. The expression levels of Notch signaling-related molecules (Notch1, Notch2, Dll3, Dll4, and Rbpj) and Th-associated cytokines (IFN-γ, IL-4, IL-10, and IL-17) were assessed via quantitative PCR (qPCR) and enzyme-linked immunosorbent assay (ELISA). In addition, the frequencies of Th1, Th2, Th17 and Treg cells were detected by flow cytometry. These experimental results indicated that activation of the Notch signaling pathway occurred in EAU rats and resulted in a severe imbalance of the Th17/Treg and Th1/Th2 ratios. PA treatment significantly alleviated ocular inflammation, inhibited activation of the Notch signaling pathway, and declined Th1, and Th17 cell differentiation, thereby restoring the Th1/Th2 and Th17/Treg balance. Collectively, PA can positively enhance the systemic immune response and improve the intraocular microenvironmental homeostasis by inhibiting activation of the Notch signaling pathway and by restoring Th1/Th2 and Th17/Treg balance, thus achieving the goal of treating uveitis.

RBP-RNA interactions in the control of autoimmunity and autoinflammation

Autoimmunity and autoinflammation arise from aberrant immunological and inflammatory responses toward self-components, contributing to various autoimmune diseases and autoinflammatory diseases. RNA-binding proteins (RBPs) are essential for immune cell development and function, mainly via exerting post-transcriptional regulation of RNA metabolism and function. Functional dysregulation of RBPs and abnormities in RNA metabolism are closely associated with multiple autoimmune or autoinflammatory disorders. Distinct RBPs play critical roles in aberrant autoreactive inflammatory responses via orchestrating a complex regulatory network consisting of DNAs, RNAs and proteins within immune cells. In-depth characterizations of RBP-RNA interactomes during autoimmunity and autoinflammation will lead to a better understanding of autoimmune pathogenesis and facilitate the development of effective therapeutic strategies. In this review, we summarize and discuss the functions of RBP-RNA interactions in controlling aberrant autoimmune inflammation and their potential as biomarkers and therapeutic targets.

Role of peripheral immune cells in spinal cord injury

Secondary spinal cord injury is caused by an inflammatory response cascade, and the process is irreversible. The immune system, as a mediator of inflammation, plays an important role in spinal cord injury. The spinal cord retains its immune privilege in a physiological state. Hence, elucidating the mechanisms by which peripheral immune cells are recruited to the lesion site and function after spinal cord injury is meaningful for the exploration of clinical therapeutic targets. In this review, we provide an overview of the multifaceted roles of peripheral immune cells in spinal cord injury.

First-in-human clinical trial of the NKT cell-stimulatory glycolipid OCH in multiple sclerosis

Background

Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system that causes the damage to the myelin sheath as well as axonal degeneration. Individuals with MS appear to have changes in the numbers and functions of T-cell subsets, leading to an immunological imbalance accompanied by enhanced autoreactivity. In previous preclinical studies, (2 S,3 S,4R)-1-O-(α-D-Galactopyranosyl)-N-tetracosanoyl-2-amino-1,3,4-nonanetriol (OCH), a synthetic analog of α-galactosylceramide stimulatory for invariant NKT (iNKT) cells, has shown therapeutic or disease-preventive immunoregulatory effects in autoimmune disease models such as experimental autoimmune encephalomyelitis (EAE).

Objectives

This study is the first-in-human study of oral OCH to evaluate the pharmacokinetics and to examine the effects on immune cells as well as related gene expression profiles.

Methods

Fifteen healthy volunteers and 13 MS patients who met the study criteria were enrolled. They were divided into five cohorts and received oral administration of various doses of granulated powder of OCH (0.3-30 mg), once per week for 4 or 13 weeks. Plasma OCH concentrations were measured by high-performance liquid chromatography. Frequencies of lymphocyte subsets in peripheral blood were evaluated by flow cytometry, and microarray analysis was performed to determine OCH-induced changes in gene expression.

Results

Oral OCH was well tolerated, and its bioavailability was found to be sufficient. Six hours after a single dose of OCH, increased frequencies of Foxp3⁺ regulatory T-cells were observed in some cohorts of healthy subjects and MS patients. Furthermore, gene expression analysis demonstrated an upregulation of several immunoregulatory genes and downregulation of pro-inflammatory genes following OCH administration.

Conclusion

This study has demonstrated immunomodulatory effects of the iNKT cell-stimulatory drug OCH in human. Safety profiles together with the presumed anti-inflammatory effects of oral OCH encouraged us to conduct a phase II trial.

Stress Suppresses Systemic Th17/Treg Imbalance in Rats with Experimental Autoimmune Uveitis

PURPOSE

To explore the effect of chronic unpredictable mild stress (CUMS) on the immune response involved in rats with experimental autoimmune uveitis (EAU).

METHODS

Lewis rats were randomly divided into control, EAU, CUMS, and EAU+CUMS groups and received relevant treatments. On days 7, 11, 14, 21 and 28, frequencies of Th17 and Treg cells and the related cytokines were analyzed.

RESULTS

The intraocular inflammation of EAU rats peaked between days 11 and 13, while the severity of inflammation of the rats in EAU+CUMS group fluctuated between 11 and 15 days. Both frequencies of Th17, Treg cells and the related cytokines exhibited a significant difference between the two groups on days 11 and 14.

CONCLUSION

CUMS may protect against the possible harmful effects of immune disorder in rats with EAU through suppressing the immune disorder of T lymphocyte and the related cytokine responses.

Research advance of natural products in tumor immunotherapy

Cancer immunotherapy has emerged as a novel anti-tumor treatment. Despite significant breakthroughs, cancer immunotherapy remains focused on several types of tumors that are sensitive to the immune system. Therefore, effective strategies to expand its indications and improve its efficacy become key factors for the further development of cancer immunotherapy. In recent decades, the anticancer activities of natural products are reported to have this effect on cancer immunotherapy. And the mechanism is largely attributed to the remodeling of the tumor immunosuppressive microenvironment. The compelling data highlight that natural products offer an alternative method option to improve immune function in the tumor microenvironment (TME). Currently, more attention is being paid to the discovery of new potential modulators of tumor immunotherapy from natural products. In this review, we describe current advances in employing natural products and natural small-molecule drugs targeting immune cells to avoid tumor immune escape, which may bring some insight for guiding tumor treatment.

New insights for regulatory T cell in lupus nephritis

Lupus nephritis (LN) is a complicated autoimmune disease marked by out-of-balance of immunological reactivity and immune tolerance. With the advance of immunotherapy in human disease, regulatory T (Treg) cells serve a crucial function in immune tolerance regulation and are characterized with suppression function as one of the most important research hotspots for autoimmunity diseases. In recent years, Treg cells have shown the robust potential for treatment to autoimmunity diseases like type I diabetic mellitus and rheumatoid arthritis. However, Treg cell therapy is poorly understood for LN patients. This review aims to summarize new insights for Treg-targeting techniques in LN patients. The current data regarding the biology features of Treg cells in LN patients is discussed. The propotion of Treg cells in LN patients have contradictory results regarding the use of different molecular markers. Forkhead box protein 3 (FOXP3) are hallmarks for control function of Treg cells. Treg cells can directly or indirectly target T cells and B cells by playing supressive role. The molecular targets for Treg cells in LN patients includes gene variants, miRNAs, and inflammatory related factors. Based on the current knowledge of Treg cell biology, several therapeutic strategies could be used to treat LN: cell transplantation, low dose IL-2 treatment, drugs target the balance of Treg and type 17 T helper (Th17) cells, and Chinese medicine.

PPAR-α Agonist Fenofibrate Ameliorates Sjögren Syndrome-Like Dacryoadenitis by Modulating Th1/Th17 and Treg Cell Responses in NOD Mice

Purpose

To investigate the effects and mechanisms of fenofibrate, a synthetic ligand of peroxisome proliferator-activated receptor α (PPAR-α), on autoimmune dacryoadenitis in a mouse model of Sjögren syndrome (SS) dry eye.

Methods

Male nonobese diabetic (NOD) mice were fed chow with or without 0.03% fenofibrate for 8 weeks, and clinical scores were determined by assessing tear secretion, fluorescein, and hematoxylin and eosin staining. Intracellular IFN-γ, IL-17, and Foxp3 in CD4+ T cells were measured by flow cytometry. The expressions of Th1, Th17, and Treg cell-related transcription factors and cytokines were detected by real-time PCR. The levels of PPAR-α and liver X receptor β (LXR-β) were detected with real-time PCR and Western blotting.

Results

Fenofibrate efficiently diminished the lymphocytic inflammation in lacrimal glands (LGs), increased tear secretion, and decreased corneal fluorescein staining in NOD mice. Meanwhile, treatment of fenofibrate evidently reduced the proportion of Th1 and Th17 cells and increased the proportion of Treg cells in vivo and vitro, together with decreased expression of T-bet, IFN-γ, RORγt, and IL-17, as well as increased expression of Foxp3 and TGF-β1 in LGs. Furthermore, fenofibrate significantly upregulated the expressions of PPAR-α and LXR-β at the protein and mRNA levels.

Conclusions

Fenofibrate potently attenuated LG inflammation in a model of autoimmune dry eye, and this effect might partially result from regulating Th1/Th17/Treg cell responses by activating PPAR-α/LXR-β signaling. These data suggest that fenofibrate may be a novel class of therapeutic agent for SS-associated dacryoadenitis.

Ongoing Clinical Trials in Aging-Related Tissue Fibrosis and New Findings Related to AhR Pathways

Fibrosis is a pathological manifestation of wound healing that replaces dead/damaged tissue with collagen-rich scar tissue to maintain homeostasis, and complications from fibrosis contribute to nearly half of all deaths in the industrialized world. Ageing is closely associated with a progressive decline in organ function, and the prevalence of tissue fibrosis dramatically increases with age. Despite the heavy clinical and economic burden of organ fibrosis as the population ages, to date, there is a paucity of therapeutic strategies that are specifically designed to slow fibrosis. Aryl hydrocarbon receptor (AhR) is an environment-sensing transcription factor that exacerbates aging phenotypes in different tissues that has been brought back into the spotlight again with economic development since AhR could interact with persistent organic pollutants derived from incomplete waste combustion. In addition, gut microbiota dysbiosis plays a pivotal role in the pathogenesis of numerous diseases, and microbiota-associated tryptophan metabolites are dedicated contributors to fibrogenesis by acting as AhR ligands. Therefore, a better understanding of the effects of tryptophan metabolites on fibrosis modulation through AhR may facilitate the exploitation of new therapeutic avenues for patients with organ fibrosis. In this review, we primarily focus on how tryptophan-derived metabolites are involved in renal fibrosis, idiopathic pulmonary fibrosis, hepatic fibrosis and cardiac fibrosis. Moreover, a series of ongoing clinical trials are highlighted.

Anti-inflammatory and immunomodulatory activity of Mangifera indica L. reveals the modulation of COX-2/mPGES-1 axis and Th17/Treg ratio

In the context of inflammation and immunity, there are fragmented and observational studies relating to the pharmacological activity of Mangifera indica L. and its main active component, mangiferin. Therefore, we aimed to analyze the potential beneficial effects of this plant extract (MIE, 90% in mangiferin) in a mouse model of gouty arthritis, to allow the evaluation of cellular immune phenotypes and the biochemical mechanism/s beyond MIE activity. Gouty arthritis was induced by the intra-articular administration of MSU crystals (200μg 20μl^-1), whereas MIE (0.1-10mgkg^-1) or corresponding vehicle (DMSO/saline 1:3) were orally administrated concomitantly with MSU (time 0), 6 and 12h after the stimulus. Thereafter, knee joint score and oedema were evaluated in addition to western blot analysis for COX-2/mPGES-1 axis. Moreover, the analysis of pro/anti-inflammatory cyto-chemokines coupled with the phenotyping of the cellular infiltrate was performed. Treatment with MIE revealed a dose-dependent reduction in joint inflammatory scores with maximal inhibition observed at 10mgkg^-1. MIE significantly reduced leukocyte infiltration and activation and the expression of different pro-inflammatory cyto-chemokines in inflamed tissues. Furthermore, biochemical analysis revealed that MIE modulated COX-2/mPGES-1 and mPGDS-1/PPARγ pathways. Flow cytometry analysis also highlighted a prominent modulation of inflammatory monocytes (CD11b⁺/CD115⁺/LY6C^hi), and Treg cells (CD4⁺/CD25⁺/FOXP3⁺) after MIE treatment. Collectively, the results of this study demonstrate a novel function of MIE to positively affect the local and systemic inflammatory/immunological perturbance in the onset and progression of gouty arthritis.

A Decreased Absolute Number of Treg Cells in Patients with Active Rheumatoid Arthritis is Associated with Elevated Serum Osteopontin Levels with Disease Progression

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic and refractory autoimmune disease characterized by synovial inflammation with unknown aetiology. Immune system dysfunction mediated by CD4⁺ T lymphocytes, which is regulated by the cytokine osteopontin (OPN), plays an important role in the pathogenesis of RA.

METHODS

In this study, the levels of peripheral CD4⁺ T subsets and serum OPN in patients with active RA were measured and analysed to determine the possible pathogenesis of RA and to provide potential therapeutic targets.

RESULTS

Serum OPN levels in both patients with active RA and patients with refractory RA were higher than those in healthy controls (HCs). Compared with HCs, the absolute numbers of Th2 cells increased in patients with active RA, while the absolute counts of Th1 and T_reg cells decreased. There was no significant difference in CD4⁺ T subset levels between new-onset and refractory patients. As the condition persisted or deteriorated, a gradual increase in the levels of OPN and gradual declines in the absolute counts of Th1 and T_reg cells were observed in patients with active RA. The fewest Th1 and T_reg cells and the highest OPN levels were observed in patients with high disease activity. The serum OPN level was only significantly negatively correlated with the absolute counts of T_reg cells in the CD4⁺ T lymphocyte subsets.

CONCLUSIONS

Fewer T_reg cells with the increase in disease activity may be related to the increased OPN concentration, which may provide new ideas and directions for the targeted immunoregulatory treatment of RA.

Cell-based therapies for rheumatoid arthritis: opportunities and challenges

Rheumatoid arthritis (RA) is the most common immune-mediated inflammatory disease characterized by chronic synovitis that hardly resolves spontaneously. The current treatment of RA consists of nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, conventional disease-modifying antirheumatic drugs (cDMARDs), biologic and targeted synthetic DMARDs. Although the treat-to-target strategy has been intensively applied in the past decade, clinical unmet needs still exist since a substantial proportion of patients are refractory or even develop severe adverse effects to current therapies. In recent years, with the deeper understanding of immunopathogenesis of the disease, cell-based therapies have exhibited effective and promising interventions to RA. Several cell-based therapies, such as mesenchymal stem cells (MSC), adoptive transfer of regulatory T cells (Treg), and chimeric antigen receptor (CAR)-T cell therapy as well as their beneficial effects have been documented and verified so far. In this review, we summarize the current evidence and discuss the prospect as well as challenges for these three types of cellular therapies in RA.

Parthenolide Suppresses T Helper 17 and Alleviates Experimental Autoimmune Encephalomyelitis

T helper (Th) cells play crucial roles in inflammation and adaptive immune system. Importantly, Th17 cells, a major pathogenic Th cell subset, are involved in the pathogenesis of multiple sclerosis (MS) and its classical animal modal experimental autoimmune encephalomyelitis (EAE). Previous studies have shown that parthenolide (PTL), a sesquiterpene lactone, possesses potent anti-cancer and anti-inflammatory activities. However, the immunosuppressive effect of PTL on the pathogenic Th17 cell and MS is unclear. In this study, we showed that PTL treatment could alleviate clinical symptoms by inhibiting inflammatory cell infiltration, reducing inflammation and demyelination of CNS. In addition, the mRNA expression of cytokines and inflammatory factors in CD4⁺ T cells, especially Th1 and Th17 cells, reduced in both CNS and peripheral immune tissue of EAE mice. Furthermore, PTL could inhibit the reactivation of MOG-specific T cells and the differentiation of naïve CD4⁺ T cells into Th17 cells in vitro. We also found that PTL inhibited nuclear factor kappa B (NF-κB) signaling and retinoid-related orphan receptor-γt (RORγt) in mouse Th17 cell and human Jurkat cell line. Taken together, our data demonstrated a critical immune-suppressive effect of PTL on autoimmune inflammation through regulating Th17 cells and the NF-κB/RORγt pathway.

The relation of CD4+CD25+Foxp3+ regulatory T cells concentration with disease activity and damage index in systemic lupus erythematosus

Introduction

Regulatory T cells (Treg) deficits, both quantitative and qualitative, are known to be possible triggers for the development of autoimmune disorders by causing T and B cells dysfunction. The contribution of Treg deficiency in the etiology of systemic lupus erythematosus (SLE) is still being debated. The aim of the present study is to evaluate the percentage of circulating CD4+CD25+Foxp3+ Treg cells in a cohort of Egyptian SLE patients and to correlate this value with the activity and damage index of these patients.

Methods

50 female patients with SLE together with an equal number of age- and sex-matched healthy controls were enrolled in the study. Flow cytometric determination of peripheral Treg cells was carried out for all participants by detecting the percentage of CD4+CD25+Foxp3+ cells to compare cases with the control group. Disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K), while disease damage was assessed using the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SLICC/ACR DI). Both indices were correlated with the percentage of CD4+CD25+Foxp3 T regulatory cells.

Results

CD4+CD25+Foxp3+ Treg cells percentage was significantly decreased in patients with SLE as compared to healthy controls. On correlating CD4+CD25+Foxp3+ Treg percentage with SLEDAI-2K, a significantly negative correlation was found. Also, there was a negative significant correlation between CD4+CD25+Foxp3+ Treg cells percentage and SLICC/ACR DI. On correlating SLEDAI-2K with damage index (SLICC/ACR DI), we found highly significant positive correlation.

Conclusion

Our study showed impaired production of CD4+CD25+Foxp3+ Tregs in SLE patients, which can play a reciprocal role with some cytokines to affect the activity of the disease and organ damage. CD4+CD25+Foxp3+ Tregs cells should be the target to determine the clinical effectiveness of new therapy to modulate Tregs besides the traditional treatments.

Norisoboldine induces the development of Treg cells by promoting fatty acid oxidation-mediated H3K27 acetylation of Foxp3

Norisoboldine (NOR), an alkaloid isolated from Radix Lindera, was previously reported to promote the differentiation of regulatory T cells (Treg cells), an important subtype of lymphocytes capable of controlling autoimmune diseases. The present study was performed to explore the mechanism of NOR in the view of cellular metabolism. A global metabolomic analysis indicated that NOR preferentially altered the fatty acid oxidation (FAO) pathway and elevated the content of related metabolites during Treg cell differentiation. The detection of oxygen consumption rate (OCR) and mRNA expression of FAO-related enzymes demonstrated that NOR promoted FAO in the early stage of Treg cell differentiation. Consistently, pharmacological or genetic inhibition of FAO markedly diminished the induction of NOR on Treg cell differentiation. Furthermore, NOR was shown to elevate the level of acetyl-CoA derived from FAO and acetylation of lysine 27 on histone 3 (H3K27) at the Foxp3 promoter and CNS2 regions. A knockdown of CPT1, the rate-limiting enzyme of FAO, weakened the promotion of NOR on the development, acetyl-CoA level, and acetylation of H3K27 of Treg cells in vitro and in the mice with collagen-induced arthritis, and attenuated the anti-arthritic effect of NOR. These findings demonstrate that NOR induces the development of Treg cells through promoting FAO, therefore, facilitating gene transcription of Foxp3 via acetyl-CoA-mediated H3K27 acetylation modification, and FAO might serve as a novel target to induce Treg cell development.

[Increased suppressor activity of transformed ex vivo regulatory T-cells in comparison with unstimulated cells of the same donor]

Regulatory T-cells CD4⁺CD25⁺FoxP3⁺CD127low (Tregs) play a key role in the maintenance of tolerance to auto antigens, inhibit function of effector T and B lymphocytes, and provide a balance between effector and regulatory arms of immunity. Patients with autoimmune diseases have decreased Treg numbers and impaired suppressive activity. Transformed ex vivo autologous Tregs could restore destroyed balance of the immune system. We developed a method for Treg precursor cell cultivation. Following the method, we were able to grown up 300-400 million of Tregs cells from 50 ml of peripheral blood during a week. Transformed ex vivo Tregs are 90-95% CD4⁺CD25⁺FoxP3⁺CD127low and have increased expression of transcription genes FoxP3 and Helios. Transformed ex vivo Tregs have increased demethylation of FoxP3 promoter and activated genes of proliferation markers Cycline B1, Ki67 and LGALS 1. Transformed ex vivo Tregs have increased suppressive activity and up to 80-90% these cells secrete cytokines TNFα и IFNγ. Our data suggest transformed ex vivo autologous Tregs have genetic, immunophenotypic and functional characteristics for regulatory T-cells and further can be used for adoptive immunotherapy autoimmune diseases and inhibition of transplantation immunity.

Induction of Foxp3 and activation of Tregs by HSP gp96 for treatment of autoimmune diseases

Upregulation and stabilization of Foxp3 expression in Tregs are essential for regulating Treg function and immune homeostasis. In this study, gp96 immunization showed obvious therapeutic effects in a Lyn^–/– mouse model of systemic lupus erythematosus. Moreover, gp96 alleviated the initiation and progression of MOG-induced experimental autoimmune encephalomyelitis. Immunization of gp96 increased Treg frequency, expansion, and suppressive function. Gene expression profiling identified the NF-κB family member p65 and c-Rel as the key transcription factors for enhanced Foxp3 expression in Treg by gp96. Mutant gp96 within its Toll-like receptor (TLR) binding domain, TLR2 knockout mice, and mice with cell-specific deletion of MyD88, were used to demonstrate that gp96 activated Tregs and induced Foxp3 expression via a TLR2-MyD88-mediated NF-κB signaling pathway. Taken together, these results show that gp96 immunization restricted antibody-induced and Th-induced autoimmune diseases by integrating Treg expansion and activation, indicating its potential clinical usefulness against autoimmune diseases.

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SLE symptoms in Lyn^–/– mice are ameliorated by gp96 immunization

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Tregs expanded by gp96 provide potential in suppressing Th-mediated EAE

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Gp96 promotes Treg proliferation, stability, and suppressive function

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Gp96 binds to and activates Treg in a TLR2-MyD88-NF-кB-Foxp3 pathway

TGF-β-induced CD4+ FoxP3+ regulatory T cell-derived extracellular vesicles modulate Notch1 signaling through miR-449a and prevent collagen-induced arthritis in a murine model

CD4⁺FOXP3⁺ Treg cells are central to the maintenance of self-tolerance and can be defective in autoimmunity. In autoimmune rheumatic diseases, dysfunctional self-tolerance, is to a large extent, caused by insufficient Treg-cell activity. Although nTregs have therapeutic effects in vivo, their relative scarcity and slow rate of in vitro expansion hinder the application of nTreg therapy. It was previously reported that EVs contribute significantly to the suppressive function of FOXP3⁺ Treg cells. Considering that the stability and plasticity of nTregs remain major challenges in vivo, we established EVs derived from in vitro TGF-β-induced Treg cells (iTreg-EVs) and assessed their functions in a murine model of autoimmune arthritis. The results demonstrated that iTreg-EVs preferentially homed to the pathological joint and efficiently prevented the imbalance in Th17/Treg cells in arthritic mice. Furthermore, we found that miR-449a-5p mediated Notch1 expression modulation and that miR-449a-5p knockdown abolished the effects of iTreg-EVs on effector T cells and regulatory T cells in vitro and in vivo. Taken together, our results show that iTreg-EVs control the inflammatory responses of recipient T cells through miR-449a-5p-dependent modulation of Notch1 and ameliorate the development and severity of arthritis, which may provide a potential cell-free strategy based on manipulating iTreg-EVs to prevent autoimmune arthritis.

Regulatory T cells enhance Th17 migration in psoriatic arthritis which is reversed by anti-TNF

Regulatory T cells (Treg) prevent the migration of effector T cells toward sites of inflammation, thereby limiting disease progression. We investigated this aspect of Treg function using psoriatic arthritis (PsA) as an exemplar of chronic inflammation. Patients with PsA had an increased Th17:Treg ratio which was reversed by anti-tumor necrosis factor (TNF) therapy. Utilizing an in vitro migration assay, Treg from patients with PsA treated with conventional therapy paradoxically boosted CCR6⁺ effector T-cell (a surrogate for Th17) migration toward CCL20. In contrast, Treg from patients with PsA treated with anti-TNF suppressed CCL20-driven effector T-cell migration. The boosting effect of TNF blockade upon Treg suppression of migration was accompanied by increased effector T-cell CCL20 production and enhanced interaction between Treg and effector T cells. This study provides mechanistic insight into Treg modulation of effector T-cell migration in patients with chronic inflammation and how this can be targeted by therapy.

Synthesized nanoparticles, biomimetic nanoparticles and extracellular vesicles for treatment of autoimmune disease: Comparison and prospect

An emerging strategy is needed to treat autoimmune diseases, many of which are chronic with no definitive cure. Current treatments only alleviate symptoms and have many side effects affecting patient quality of life. Recently, nanoparticle drug delivery systems, an emerging method in medicine, has been used to target cells or organs, without damaging normal tissue. This approach has led to fewer side effects, along with a strong immunosuppressive capacity. Therefore, a nanotechnology approach may help to improve the treatment of autoimmune diseases. In this review, we separated nanoparticles into three categories: synthesized nanoparticles, biomimetic nanoparticles, and extracellular vesicles. This review firstly compares the typical mechanism of action of these three nanoparticle categories respectively in terms of active targeting, camouflage effect, and similarity to parent cells. Then their immunomodulation properties are discussed. Finally, the challenges faced by all these nanoparticles are described.

Modular immune-homeostatic microparticles promote immune tolerance in mouse autoimmune models

The therapeutic goal for autoimmune diseases is disease antigen-specific immune tolerance without nonspecific immune suppression. However, it is a challenge to induce antigen-specific immune tolerance in a dysregulated immune system. In this study, we developed immune-homeostatic microparticles (IHMs) that treat multiple mouse models of autoimmunity via induction of apoptosis in activated T cells and reestablishment of regulatory T cells. Specifically, in an experimental model of colitis, IHMs rapidly released monocyte chemotactic protein-1 after intravenous administration, which recruited activated T cells and then induced their apoptosis by conjugated Fas ligand on the IHM surface. This triggered professional macrophages to ingest apoptotic T cells and produce high quantities of transforming growth factor-β, which drove regulatory T cell differentiation. Furthermore, the modular design of IHMs allowed IHMs to be engineered with the autoantigen peptides that can reduce disease in an experimental autoimmune encephalomyelitis mouse model and a nonobese diabetic mouse model. This was accomplished by sustained release of the autoantigens after induction of T cell apoptosis and transforming growth factor-β production by macrophages, which promoted to establish an immune tolerant environment. Thus, IHMs may be an efficient therapeutic strategy for autoimmune diseases through induction of apoptosis and reestablishment of tolerant immune responses.

Molecular docking analysis of stachydrine and sakuranetin with IL-6 and TNF-α in the context of inflammation

Inflammation is a process triggered by pro-inflammatory cytokines and anti-inflammatory molecules. Therefore, it is of interest to document the anti-inflammatory activity of Stachydrine and Sakuranetin against the inflammatory target proteins IL-6 and TNF-α by using molecular docking analysis. Both compounds showed good binding features with the selected target proteins. Compared to Sakuranetin, the Stachydrine have low binding energy and good hydrogen bond interactions. Hence, data show that Stachydrine possessed high and specific inhibitory activity on tumor necrosis factor-α and interleukin-6.

Deconvolution of sarcoma methylomes reveals varying degrees of immune cell infiltrates with association to genomic aberrations

BACKGROUND

Soft-tissue sarcomas (STS) are a heterogeneous group of mesenchymal tumors for which response to immunotherapies is not well established. Therefore, it is important to risk-stratify and identify STS patients who will most likely benefit from these treatments.

RESULTS

To reveal shared and distinct methylation signatures present in STS, we performed unsupervised deconvolution of DNA methylation data from the TCGA sarcoma and an independent validation cohort. We showed that leiomyosarcoma can be subclassified into three distinct methylation groups. More importantly, we identified a component associated with tumor-infiltrating leukocytes, which suggests varying degrees of immune cell infiltration in STS subtypes and an association with prognosis. We further investigated the genomic alterations that may influence tumor infiltration by leukocytes including RB1 loss in undifferentiated pleomorphic sarcomas and ELK3 amplification in dedifferentiated liposarcomas.

CONCLUSIONS

In summary, we have leveraged unsupervised methylation-based deconvolution to characterize the immune compartment and molecularly stratify subtypes in STS, which may benefit precision medicine in the future.

Low-dose IL-2 therapy limits the reduction in absolute numbers of circulating regulatory T cells in rheumatoid arthritis

Background:

Circulating regulatory T cells (Tregs) are responsible for mediating immune tolerance and maintaining immunological homeostasis. Decreases in Tregs may be involved in the onset of rheumatoid arthritis (RA). Low-dose interleukin-2 (IL-2) has been considered for the treatment of inflammatory diseases mediated by T cells. This study focused on the status of circulating CD4⁺T subsets and the clinical feasibility of IL-2 therapies in patients with RA.

Methods:

The subjects included 888 patients with RA and 100 healthy controls (HCs); 233 RA patients received IL-2 treatment with 0.5 million international units (MIU)/day from days 1 through 5. The demographic features, disease activity, and levels of CD4+T cells measured by modified flow cytometry were collected in all RA patients before and after treatment.

Results:

RA patients had lower absolute Treg counts (but not Th17) compared with HCs, which was associated with disease activity; previously treated RA patients had the fewest circulating Tregs (p < 0.05). Patients treated with low-dose IL-2 had a three-fold increase in absolute anti-inflammatory Treg counts, as well as a two-fold increase in the other CD4⁺T subsets. Moreover, post-treatment levels of markers of disease activity in RA patients treated with IL-2 were significantly lower than the baseline values (p < 0.001), with no apparent side effects.

Conclusion:

Decreased absolute counts of circulating CD4⁺T lymphocyte subsets were observed in patients with RA. Circulating Tregs, which mediate immune tolerance, may be involved in the pathogenesis and progression of RA; however, this was ameliorated by low-dose IL-2, without obvious side effects.

Plain language summary

Low-dose IL-2 treatment for rheumatoid arthritis

• Circulating Tregs may be involved in the pathogenesis and progression of RA.

• The absolute count of Tregs was significantly correlated with disease activity measures.

• Low-dose IL-2 was able to effectively expade Tregs and help for RA patients’ symptoms remission without evaluated side effects.

Peripheral Blood from Rheumatoid Arthritis Patients Shows Decreased Treg CD25 Expression and Reduced Frequency of Effector Treg Subpopulation

Rheumatoid arthritis (RA) is a common autoimmune disease characterized by immune cell infiltration of the synovium, leading to the loss of cartilage, bone, and joint function. Although regulatory T (T_reg) cells are thought to modulate the initiation and progression of RA, a consensus has yet to be reached regarding the function and composition of T_reg cells in RA patients. To address these discrepancies, we analyzed not only the total T_reg frequency but also that of T_reg subpopulations in the peripheral blood of RA patients and healthy controls by flow cytometry. We found that the total T_reg population was not significantly different between RA and control subjects. However, the effector T_reg cell subgroup, defined as CD45RA⁻CD25^hi, showed markedly decreased frequency in RA patients. In addition, the total T_reg population from RA patients showed a significant decline in the expression of CD25. Both the naïve and effector T_reg subgroups also showed marked reduction of CD25 expression in RA patients compared to controls. These data suggest that the decreased frequency of effector T_reg cells and overall reduction of CD25 expression in T_reg cells in the peripheral blood may be evidence of altered T_reg homeostasis associated with RA pathogenesis.

Longdan Xiegan Decoction alleviates experimental autoimmune uveitis in rats by inhibiting Notch signaling pathway activation and Th17 cell differentiation

This study aimed to investigate the dynamic effects of the traditional Chinese medicine compound Longdan Xiegan Decoction (LXD) on the inhibition of Notch signaling pathway activation and T helper (Th) cell differentiation in rats with experimental autoimmune uveitis (EAU). Based on a network pharmacology strategy, we conducted protein interaction network analysis to construct an active ingredient-disease treatment network. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were further used to screen out the possible signaling pathways regulated by LXD in the treatment of uveitis. In the subsequent functional studies, we established an EAU rat model and investigated the regulatory role of LXD in the Notch signaling pathway and Th cell differentiation in rats with EAU. Female Lewis rats were randomly divided into a normal control (NC) group, an EAU group, and an LXD group. After the induction of EAU, the ocular inflammation and pathological changes in the rats in each group were observed; for documentation, a scanning laser ophthalmoscope (SLO) was used to observe fundus inflammation on day 12 after immunization. Additionally, quantitative polymerase chain reaction (Q-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to detect the expression of Notch1, DLL4, IL-10 and IL-17A in the spleen, lymph nodes and ocular tissues of each group at 0, 6, 9, 12, 15 and 18 days after immunization. In addition, the dynamic frequencies of the CD4+, CD8+, Th17 and Treg cell subsets in the spleen, lymph nodes and ocular tissues were measured by flow cytometry. We found that the Notch signaling pathway was activated and the Th17 frequency was elevated in rats with EAU, leading to disrupted CD4+/CD8+ and Th17/Treg balance. The expression of Notch1, DLL4 and IL-17 mRNA and proteins in the EAU and LXD groups reached a peak on day 12, and then gradually decreased (all P < 0.05), and the ratios of the CD4+/CD8+ and Th17/Treg also peaked on day 12. However, after treatment with LXD, the expression of Notch1, DLL4 and IL-17 mRNA and proteins was significantly decreased (all P < 0.05), and the CD4+/CD8+ and Th17/Treg ratios significantly gradually returns to balance. LXD can efficiently inhibit Th17 cell differentiation, decrease inflammatory cytokine expression, and restore the CD4+/CD8+ and Th17/Treg balance by inhibiting the activation of the Notch signaling pathway in rats with EAU, thus effectively alleviating eye inflammation, protecting eye tissue structures, and positively regulating the immune state of the whole body and the intraocular microenvironment.

Low-Dose IL-2 Therapy in Autoimmune and Rheumatic Diseases

Regulatory T cells (Treg) are crucial for the maintenance of peripheral tolerance and for the control of ongoing inflammation and autoimmunity. The cytokine interleukin-2 (IL-2) is essentially required for the growth and survival of Treg in the peripheral lymphatic tissues and thus plays a vital role in the biology of Treg. Most autoimmune and rheumatic diseases exhibit disturbances in Treg biology either at a numerical or functional level resulting in an imbalance between protective and pathogenic immune cells. In addition, in some autoimmune diseases, a relative deficiency of IL-2 develops during disease pathogenesis leading to a disturbance of Treg homeostasis, which further amplifies the vicious cycle of tolerance breach and chronic inflammation. Low-dose IL-2 therapy aims either to compensate for this IL-2 deficiency to restore a physiological state or to strengthen the Treg population in order to be more effective in counter-regulating inflammation while avoiding global immunosuppression. Here we highlight key findings and summarize recent advances in the clinical translation of low-dose IL-2 therapy for the treatment of autoimmune and rheumatic diseases.

Bee venom phospholipase A2 alleviates collagen-induced polyarthritis by inducing Foxp3+ regulatory T cell polarization in mice

The mechanism underlying bee venom (BV) therapy is still controversial, with opinions ranging from constituent-based pharmacological action to homeopathic-like activity. The purpose of this study was to examine whether BV phospholipase A2 (bvPLA2), an enzymatic component of BV, is a novel anti-inflammatory and anti-arthritic mediator capable of stimulating CD25+ Foxp3+ regulatory T cell (Treg) polarization in a mouse model of human rheumatoid arthritis (RA). An experimental model of RA was established in male DBA/1 mouse by 2-week-interval injections of 100 μg type II collagen emulsified in complete (first injection) or incomplete Freund's adjuvant (second injection) at the base of the tail. During arthritis development, bvPLA2 (0.1, 0.5, 1.0 mg/kg) and/or Treg inhibitors such as anti-CD25 antibodies and peptide 60 (P60) were injected intraperitoneally for 5 weeks. Arthritic symptoms and the expansion of Tregs were then assessed by behavioral assessments, histological and micro-CT imaging, and flow cytometry. bvPLA2 injections significantly alleviated arthritic behaviors such as squeaking and joint swelling, consistent with changes seen on both histological and micro-CT images. The anti-arthritic effects of bvPLA2 were blocked by intraperitoneal injections of 0.25 mg/kg anti-CD25 antibody and 10 μg/kg P60, as determined by behavioral assessments. Flow cytometric analysis of dendritic cells, B cells, and major T cell subsets from spleens revealed a significant depletion of Tregs following anti-CD25 antibody, but not P60, treatment. bvPLA2 treatment exerted significant anti-inflammatory and anti-arthritic activities in a mouse model of RA via the induction of Tregs.

Regulatory T Cell Therapy Following Liver Transplantation

Liver transplantation (LT) is considered the gold standard of curative treatment for patients with end-stage liver disease or nonresectable hepatic malignant tumors. Rejection after LT is the main nontechnical factor affecting the prognosis of recipients. Medical and surgical advances, combined with improved immunosuppression with drugs such as calcineurin inhibitors (CNIs), have contributed to an increase in 1-year graft survival to around 80%. However, medium- and long-term improvements in LT outcomes have lagged behind. Importantly, CNIs and other classical immunosuppressive drugs are associated with significant adverse effects, including malignancies, cardiovascular disease, and severe renal dysfunction. Immunomodulation using regulatory T cells (Tregs) is emerging as a promising alternative to classical immunosuppression. Since their discovery, the immunomodulatory effects of Tregs have been demonstrated in a range of diseases. This has rejuvenated the interest in using Tregs as a therapeutic strategy to induce immune tolerance after LT. In this review, we first summarize the discovery and development of Tregs. We then review the preclinical data supporting their production, mechanism of action, and therapeutic efficacy followed by a summary of relevant clinical trials. Finally, we discuss the outstanding challenges of Treg therapy and its future prospects for routine use in LT.

A prognostic nomogram for lung adenocarcinoma based on immune-infiltrating Treg-related genes: from bench to bedside

Background

Accumulating evidence suggests that lymphocyte infiltration in the tumor microenvironment is positively correlated with tumorigenesis and development, while the role of Tregs (regulatory T cells) has been controversial. Therefore, we attempted to discover the possible value of Tregs for lung adenocarcinoma (LUAD).

Methods

The gene-sequencing data of LUAD were applied from three Gene Expression Omnibus (GEO) datasets—GSE10072, GSE32863 and GSE43458; the corresponding fractions of tumor-infiltrating immune cells were extracted from the CIBERSORTx portal. Weighted gene coexpression network analysis (WGCNA) and protein-protein interaction (PPI) network analysis were conducted to identify the significant module and candidate genes related to Tregs. The role of candidate genes in LUAD was further verified using data from The Cancer Genome Atlas (TCGA) database. Finally, we constructed a nomogram model to predict the prognosis of LUAD by plotting Kaplan-Meier (K-M), receiver operating characteristic (ROC) and calibration curves, which elucidated the performance of the nomogram.

Results

In total, 10,047 genes in 333 samples (196 tumor and 137 normal samples) from the GEO database were included. By WGCNA and PPI analysis, we identified a significant black module and 36 candidate genes related to Treg. Next, the candidate genes were verified using TCGA data by Cox regression analysis to screen 13 hub genes that stratified LUAD patients into low- or high-risk groups. Low-risk patients showed a significantly longer overall survival (OS) than high-risk patients (3-year OS: 70.2% vs. 35.2%; 5-year OS: 36.6% vs. 0; P=1.651E-09), and the areas under the ROC curves (AUCs) showed good (3-year AUC: 0.733; 5-year AUC: 0.777). Next, we constructed a survival nomogram combining the hub genes and clinical parameters; the low-risk patients still showed a favorable prognosis compared with that of the high-risk patients (P=7.073E-13), and the AUCs were better (3-year AUC: 0.763; 5-year AUC: 0.873).

Conclusions

We revealed the role of immune-infiltrating Treg-related genes in LUAD and constructed a prognostic nomogram, which may help clinicians make optimal therapeutic decisions and help patients obtain better outcomes.

The role of Treg subtypes in glomerulonephritis

While Th1 and Th17 T effector cells are pathogenic drivers of glomerulonephritis (GN), regulatory T cells (Tregs) potently protect from renal tissue injury. Recently, it has become evident that different Treg subtypes exist. Among these are lineage specific Treg1 and Treg17 cells, which are specialized to down regulate either Th1 or Th17 T effector cell responses. Interestingly, programming of specialized Tregs and the corresponding T helper effector cells depend on the same lineage specific master transcription factors Tbet (Th1/Treg1) and STAT3 (Th17/Treg17). Furthermore, early control of T effector cell priming in secondary lymphoid organs by specialized Tregs was described. One central mechanism of T effector cell control by the corresponding Treg subtype seems to be expression of the same chemokine receptor repertoire, which facilitates their co-localization. More recently, another intriguing Treg subset was identified, which expresses Foxp3 together with the Th17 characteristic transcription factor RORγt. While these Foxp3⁺RORγt⁺ Tregs were shown to be highly immunosuppressive, studies in GN also identified pro-inflammatory potential via secretion of IL-17. Many questions regarding this unusual Treg subset remain, including their origin, stability, and mechanisms of action. Further characterization of the renal Treg landscape during GN will help to identify novel immunosuppressive mechanisms and develop successful Treg-directed therapies. In this review, we summarize the currently available data about specialized Treg subsets and discuss their role in GN.