Regulatory T Cell Plasticity and Stability and Autoimmune Diseases

Circulating CD45RA-Foxp3++ Treg cells serve as a biomarker for predicting minimal clinical manifestations status of myasthenia gravis

AIMS

Regulatory T cells (Tregs) are key mediators of the induction of immune tolerance; however, the mechanisms by which they regulate myasthenia gravis (MG) are not fully understood. This study aimed to explore the characteristics of Tregs and their subpopulations in the peripheral blood of patients with minimal clinical manifestations (MM) of MG and identify biomarkers that predict MM-MG for treatment guidance.

MATERIALS AND METHODS

The clinical data of patients with general MG who visited our hospital were retrospectively analyzed. Age- and sex-matched volunteers were selected as healthy controls (HC). Flow cytometry was used to determine the proportion, function, and subpopulations of total Tregs. A correlation analysis was conducted for subpopulation proportions and MG disease severity.

KEY FINDINGS

A total of 27 cases of MM-MG, 40 cases of naїve-MG, and 33 cases of HC were included in this study. The number of total Tregs and the suppressive function of total Tregs were elevated in patients with MM-MG compared to those of patients with naїve-MG. Further analysis revealed that the frequency of CD45RA-Foxp3++ Tregs (a-Tregs) negatively correlated with quantitative myasthenia gravis (QMG) scores for patients with naїve-MG. In addition, the number of a-Tregs was significantly greater in patients with MM-MG than in patients with naїve-MG, and CD45RA-Foxp3+ Tregs expressed higher and lower levels of CTLA-4 and CXCR3, respectively.

SIGNIFICANCE

CD45RA-Foxp3++ Tregs were significantly more abundant and highly expressed surface inhibitory molecules in patients with MM-MG. This profile may serve as a predictive biomarker for MM-MG.

Alloimmune Causes of Recurrent Pregnancy Loss: Cellular Mechanisms and Overview of Therapeutic Approaches

Recurrent pregnancy loss (RPL) is a complex early pregnancy complication affecting 1-2% of couples and is often linked to immune dysfunction. Aberrations in T and B cell subpopulations, as well as natural killer (NK) cell activity, are particularly influential, with studies showing that abnormal NK cell activation and imbalances in T and B cell subtypes contribute to immune-mediated miscarriage risk. Successful pregnancy requires a tightly regulated balance between pro-inflammatory and anti-inflammatory immune responses. In the early stages, inflammation supports processes such as trophoblast invasion and spiral artery remodeling, but this must be tempered to prevent immune rejection of the fetus. In this review, we explore the underlying immune mechanisms of RPL, focusing on how dysregulated T, B, and NK cell function disrupts maternal tolerance. Specifically, we discuss the essential role of uterine NK cells in the early stages of vascular remodeling in the decidua and regulate the depth of invasion by extravillous trophoblasts. Furthermore, we focus on the delicate Treg dynamics that enable the maintenance of optimal immune homeostasis, where the balance, and not only the quantity of Tregs, is crucial for fostering maternal-fetal tolerance. Other T cell subpopulations, such as Th1, Th2, and Th17 cells, also contribute to immune imbalance, with Th1 and Th17 cells promoting inflammation and potentially harming fetal tolerance, while Th2 cells support immune tolerance. Finally, we show how changes in B cell subpopulations and their functions have been associated with adverse pregnancy outcomes. We further discuss current therapeutic strategies aimed at correcting these immune imbalances, including intravenous immunoglobulin (IVIg), glucocorticoids, and TNF-α inhibitors, examining their efficacy, challenges, and potential side effects. By highlighting both the therapeutic benefits and limitations of these interventions, we aim to offer a balanced perspective on clinical applications for women facing immune-related causes of RPL.

Impairment of regulatory T cell stability in axial spondyloarthritis: role of EZH2 and pSTAT5

Background and objectives

Axial spondyloarthritis (axSpA) is a chronic inflammatory disease involving the spine, peripheral joints, and entheses. Functional impairment of regulatory T cells (Treg) is linked to inflammatory diseases, but limited data is available regarding Treg involvement in axSpA. Treg stability refers to their ability to maintain their functions and characteristics in pro-inflammatory environments. EZH2 and phosphorylated STAT5 (pSTAT5) play a critical role in maintaining Treg stability. We aimed to characterize Treg stability in patients with axSpA.

Methods

Peripheral blood mononuclear cells (PBMCs) from axSpA patients, either naïve from targeted therapy or treated by TNF inhibitors (TNFi), and from healthy donors (HD), were freshly isolated. Expression of stability (EZH2, pSTAT5) and suppressive (TNFR2 and CD39) markers by Treg was analyzed by flow cytometry.

Results

EZH2 expression by Treg was decreased in axSpA patients as compared to HD (p<0.01). Mechanistic study showed that inhibition of EZH2 attenuated Treg differentiation and suppressive phenotype in vitro. EZH2 was predominantly expressed by highly suppressive TNFR2+ and CD39+ Treg. Additionally, axSpA patients also exhibited a reduced frequency of pSTAT5+ Treg compared to HD (p<0.05), and pSTAT5+ Treg frequency increased at 3 months of TNFi treatment compared to baseline (p<0.05). This last result suggested a restoration of Treg stability upon TNFi treatment.

Conclusion

By highlighting a deficient expression of EZH2 and pSTAT5 by Treg, we revealed an impaired Treg stability in axSpA. Deciphering the pathways influenced by these molecules is necessary to assess the potential therapeutic benefits of restoring Treg stability in axSpA.

Effect of thymectomy on the frequencies of peripheral regulatory B and T lymphocytes in patients with Myasthenia gravis-a pilot study

AIM

We aimed to investigate the relationship between the peripheral lymphocyte subset frequency and thymectomy in patients with myasthenia gravis (MG).

MATERIALS AND METHODS

The frequencies of regulatory B (Breg) and regulatory T (Treg) cells in peripheral blood samples obtained from 69 patients with MG and 10 healthy controls were analyzed using flow cytometry. Serum acetylcholine receptor antibodies (AchR-Ab) were measured. Patients with MG were subdivided into pre-thymectomy, post-thymectomy, and normal thymus control group.

RESULTS

The percentage of Breg cells was significantly decreased in both the pre-thymectomy (7.92 ± 1.30%) and post-thymectomy (8.14 ± 1.34%) groups compared to healthy controls (16.02 ± 2.78%) and reduced in the exacerbation and relapse phase compared to the stable maintenance stage. The proportion of cluster of differentiation (CD) 4 + CD25 + T cells and CD4 + CD25 + CD127low/- Treg cells in MG patients were not significantly different than healthy controls. AchR-Ab titers in aggravating or recurrence patients after thymectomy were significantly higher than that of the stable remission patients (11.13 ± 0.70 and 6.03 ± 0.85 nmol/L, respectively; p < 0.001).

CONCLUSION

The frequency of Breg cells may serve as a potential indicator of MG prognosis, while Treg cell frequency did not demonstrate the same prognostic ability. The concentration of AchR-Ab can be used as a dynamic monitoring index of disease severity in patients with MG.

One-carbon metabolism shapes T cell immunity in cancer

One-carbon metabolism (1CM), comprising folate metabolism and methionine metabolism, serves as an important mechanism for cellular energy provision and the production of vital signaling molecules, including single-carbon moieties. Its regulation is instrumental in sustaining the proliferation of cancer cells and facilitating metastasis; in addition, recent research has shed light on its impact on the efficacy of T cell-mediated immunotherapy. In this review, we consolidate current insights into how 1CM affects T cell activation, differentiation, and functionality. Furthermore, we delve into the strategies for modulating 1CM in both T cells and tumor cells to enhance the efficacy of adoptively transferred T cells, overcome metabolic challenges in the tumor microenvironment (TME), and maximize the benefits of T cell-mediated immunotherapy.

Innate and Adaptive Immune Responses in Intestinal Transplant Rejection: Through the Lens of Inflammatory Bowel and Intestinal Graft-Versus-Host Diseases

Intestinal transplantation is a life-saving procedure utilized for patients failing total parenteral nutrition. However, intestinal transplantattion remains plagued with low survival rates and high risk of allograft rejection. The authors explore roles of innate (macrophages, natural killer cells, innate lymphoid cells) and adaptive immune cells (Th1, Th2, Th17, Tregs) in inflammatory responses, particularly inflammatory bowel disease and graft versus host disease, and correlate these findings to intestinal allograft rejection, highlighting which effectors exacerbate or suppress intestinal rejection. Better understanding of this immunology can open further investigation into potential biomolecular targets to develop improved therapeutic treatment options and immunomonitoring techniques to combat allograft rejection and enhance patient lives.

Osteopontin Regulates Treg Cell Stability and Function with Implications for Anti-Tumor Immunity and Autoimmunity

Foxp3-expressing regulatory T (Treg) cells represent the most highly immunosuppressive cell in the tumor microenvironment (TME) that halts effective anti-tumor immunity. Osteopontin (Opn), an extracellular matrix (ECM) glycophosphoprotein, plays key roles in many types of immune-related diseases and is associated with cancer aggressiveness when expressed by tumor cells. However, its role in Foxp3Treg heterogeneity, function, and stability in the TME is poorly defined. We generated mice with a Foxp3-specific deletion of Opn and assessed the ability of Opn-deficient Tregs to suppress inflammation. As these mice aged, they developed a scurfy-like syndrome characterized by aberrant and excessive activation of effector T cells. We evaluated and further confirmed the reduced suppressive capacity of Opn-deficient Tregs in an in vivo suppression assay of colitis. We also found that mice with Opn-deficient Foxp3+ Tregs have enhanced anti-tumor immunity and reduced tumor burden, associated with an unstable Treg phenotype, paralleled by reduced Foxp3 expression in tumor-infiltrating lymphocytes. Finally, we observed reduced Foxp3 and Helios expression in Opn-deficient Tregs compared to wild-type controls after in vitro activation. Our findings indicate that targeting Opn in Tregs reveals vigorous and effective ways of promoting Treg instability and dysfunction in the TME, facilitating anti-tumor immunity.

Causal role of immune cells in bipolar disorder: a Mendelian randomization study

Background

The understanding of the immunological mechanisms underlying bipolar disorder (BD) has enhanced in recent years due to the extensive use of high-density genetic markers for genotyping and advancements in genome-wide association studies (GWAS). However, studies on the relationship between immune cells and the risk of BD remain limited, necessitating further investigation.

Methods

Bidirectional two-sample Mendelian Randomization (MR) analysis was employed to investigate the causal association between immune cell morphologies and bipolar disorder. Immune cell traits were collected from a research cohort in Sardinia, whereas the GWAS summary statistics for BD were obtained from the Psychiatric Genomics Consortium. Sensitivity analyses were conducted, and the combination of MR-Egger and MR-Presso was used to assess horizontal pleiotropy. Cochran's Q test was employed to evaluate heterogeneity, and the results were adjusted for false discovery rate (FDR).

Results

The study identified six immune cell phenotypes significantly associated with BD incidence (P< 0.01). These phenotypes include IgD- CD27- %lymphocyte, CD33br HLA DR+ CD14- AC, CD8 on CD28+ CD45RA+ CD8br, CD33br HLA DR+ AC, CD14 on CD14+ CD16+ monocyte, and HVEM on CD45RA- CD4+. After adjusting the FDR to 0.2, two immune cell phenotypes remained statistically significant: IgD-CD27-% lymphocyte (OR=1.099, 95% CI: 1.051-1.149, P = 3.51E-05, FDR=0.026) and CD33br HLA DR+ CD14-AC (OR=0.981, 95% CI: 0.971-0.991, P = 2.17E-04, FDR=0.079). In the reverse MR analysis, BD significantly impacted the phenotypes of four monocytes (P< 0.01), including CD64 on CD14+ CD16+ monocyte, CD64 on monocyte, CX3CR1 on CD14- CD16-, CD64 on CD14+ CD16- monocyte. However, after applying the FDR correction (FDR < 0.2), no statistically significant results were observed.

Conclusions

This MR investigation reveals associations between immune cell phenotypes, bipolar disorder, and genetics, providing novel perspectives on prospective therapeutic targets for bipolar disorder.

Histone deacetylases facilitate Th17-cell differentiation and pathogenicity in autoimmune uveitis via CDK6/ID2 axis

INTRODUCTION

Autoimmune uveitis (AU) is a prevalent ocular autoimmune disease leading to significant visual impairment. However, underlying pathogenesis of AU required to develop more efficient therapy remain unclear.

METHODS

We isolated peripheral blood mononuclear cells (PBMCs) from AU patients and performed single-cell RNA sequencing (scRNA-seq). Besides, experimental autoimmune uveitis (EAU) model was established and treated with histone deacetylase inhibitor (HDACi) Belinostat or vehicle. We extracted immune cells from Blank, EAU, and HDACi-treated EAU mice and used scRNA-seq, flow cytometry, siRNA, specific inhibitors, and adoptive transfer experiments to explore the role of HDACs and its downstream potential molecular mechanisms in the immune response of EAU and AU.

RESULTS

We found highly expressed histone deacetylases (HDACs) family in AU patients and identified it as a key factor related to CD4+ effector T cell differentiation in the pathogenesis of AU. Our further studies showed that targeted inhibition of HDACs effectively alleviated EAU, restored its Th17/Treg balance, and reduced inflammatory gene expression, especially in CD4+ T cells. Post-HDACs inhibition, Treg proportions increased with enhanced immunomodulatory effects. Importantly, HDACs exhibited a positive promoting role on Th17 cells. Based on scRNA-seq screening and application of knock-down siRNAs and specific inhibitors in vitro and vivo, we identified CDK6 as a key downstream molecule regulated by HDAC1/3/6 through acetyl-histone H3/p53/p21 axis, which is involved in Th17 pathogenicity and EAU development. Additionally, HDACs-regulated CDK6 formed a positive loop with ID2, inducing PIM1 upregulation, promoting Th17 cell differentiation and pathogenicity, and correlates with AU progression.

CONCLUSION

Based on the screening of clinical samples and downstream molecular functional validation experiments, we revealed a driving role for HDACs and the HDACs-regulated CDK6/ID2 axis in Th17 cell differentiation and pathogenicity in AU, proposing a promising therapeutic strategy.

Epigenetic regulation of human FOXP3+ Tregs: from homeostasis maintenance to pathogen defense

Regulatory T cells (Tregs), characterized by the expression of Forkhead Box P3 (FOXP3), constitute a distinct subset of T cells crucial for immune regulation. Tregs can exert direct and indirect control over immune homeostasis by releasing inhibitory factors or differentiating into Th-like Treg (Th-Treg), thereby actively contributing to the prevention and treatment of autoimmune diseases. The epigenetic regulation of FOXP3, encompassing DNA methylation, histone modifications, and post-translational modifications, governs the development and optimal suppressive function of Tregs. In addition, Tregs can also possess the ability to maintain homeostasis in diverse microenvironments through non-suppressive mechanisms. In this review, we primarily focus on elucidating the epigenetic regulation of Tregs as well as their multifaceted roles within diverse physiological contexts while looking forward to potential strategies involving augmentation or suppression of Tregs activity for disease management, particularly in light of the ongoing global COVID-19 pandemic.

Many Faces of Regulatory T Cells: Heterogeneity or Plasticity?

Regulatory T cells (Tregs) are essential for maintaining the immune balance in normal and pathological conditions. In autoimmune diseases and transplantation, they restrain the loss of self-tolerance and promote engraftment, whereas in cancer, an increase in Treg numbers is mostly associated with tumor growth and poor prognosis. Numerous markers and their combinations have been used to identify Treg subsets, demonstrating the phenotypic diversity of Tregs. The complexity of Treg identification can be hampered by the unstable expression of some markers, the decrease in the expression of a specific marker over time or the emergence of a new marker. It remains unclear whether such phenotypic shifts are due to new conditions or whether the observed changes are due to initially different populations. In the first case, cellular plasticity is observed, whereas in the second, cellular heterogeneity is observed. The difference between these terms in relation to Tregs is rather blurred. Considering the promising perspectives of Tregs in regenerative cell-based therapy, the existing confusing data on Treg phenotypes require further investigation and analysis. In our review, we introduce criteria that allow us to distinguish between the heterogeneity and plasticity of Tregs normally and pathologically, taking a closer look at their diversity and drawing the line between two terms.

Rheumatoid arthritis autologous synovial fluid affects the plasticity and function of peripheral and induced T regulatory cells in vitro

The synovial fluid (SF) microenvironment in rheumatoid arthritis (RA) may alter the stability and function of Tregs. In the present study, we assessed cytokine levels and percentage of Tregs, Tregs expressing CXCR3 (Th1-like Treg), CCR6 (Th17-like Treg) in RA peripheral blood (PB) and RA-SF using fluorescence cytometry. Effect of autologous SF on plasticity and function of RA-PB Tregs (pTregs; CD4+CD25hiCD127Lo/-) and induced vimentin-pulsed Tregs (iTregsVIM) was assessed in vitro. Cytokines and percentage of Th1-like and Th17-like Tregs were higher in RA-PB than OA-PB; higher in RA-SF than osteoarthritis (OA)-SF. Compared to OA-SF exposed OA-pTregs, RA-SF exposed RA-pTregs showed higher percentage of Th1-like (11% vs 20%) and Th17-like (16% vs 36%) Tregs; higher T-bet (p = 0.0001), RORγ (p = 0.0001) and lower FOXP3 (p = 0.0001) gene expression; and diminished percentage suppression of autologous T effector cells (36% vs 74%). RA-SF exposed iTregsVIM showed increased percentage of Th1-like and Th17-like Tregs compared to iTregsVIM exposed to AB serum (8% vs 0.1%; 21% vs 0.1%). IL-2, Tocilizumab and 5-azacytidine reduced the conversion of iTregsVIM (8% vs 2.4%; 21% vs 6.9%), when used in combination. To conclude, microenvironment in the RA synovial fluid is possibly responsible for conversion of pTregs into Th-like Tregs and their functional loss. A blockade of cytokine receptors and methyl transferases could inhibit Tregs conversion, providing clinical relevance for future Tregs targeting therapies.

Conventional Tregs in treatment-naïve rheumatoid arthritis are deficient in suppressive function with an increase in percentage of CXCR3 and CCR6 expressing Tregs

In rheumatoid arthritis (RA), immune homeostasis is maintained by T regulatory cells (Tregs) that in an inflammatory milieu can change towards T-helper-like phenotypes (Th-like Tregs). Our aim was to examine the phenotypic and functional characteristics of CD4+CD25+CD127lo/- Tregs, Th-like Tregs and T effector (Teff) cells in the peripheral blood (PB) and synovial fluid (SF) of treatment-naïve early RA, as compared to osteoarthritis (OA) and healthy control (HC) peripheral blood. Frequencies of Tregs, CXCR3, CCR6 expressing Tregs (Th-like Tregs), and Teff cells were analyzed using flow cytometry in RA (n = 80), OA (n = 20), and HC (n = 40). Cytokine concentrations of the respective T cell subsets in plasma and SF were measured using flow cytometric bead array. Tregs sorted from RA and HC PB using magnetic beads were analyzed for functional capacities by CFSE proliferation assay and FOXP3 gene expression using real-time PCR. We observed that the frequencies of Th17 cells in PB and SF were significantly higher in RA when compared to HC, whereas Tregs were lower in PB and high in SF compared to HC and OA respectively. Th1- and Th17-related pro-inflammatory cytokines IL12p70, INF-γ, TNF-α, and IL-6, and IL-17A were significantly higher in the plasma and SF of RA. Tregs expressing CXCR3 (Th1-like Tregs) and CCR6 (Th17-like Treg) were significantly higher in PB and SF of RA compared to controls and was positively associated with seropositivity and disease activity. Treg cells isolated from peripheral blood of RA showed decreased function and reduced FOXP3 gene expression compared to HC. In our study, we have demonstrated higher frequencies of Th1 and Th17 cells and increased circulatory and SF pro-inflammatory cytokines (IL12P70, INF-γ, IL-6, IL-17A, and TNF-α) in RA. This inflammatory milieu might alter total Tregs frequencies and influence conversion of Tregs into Th-like Tregs.

Autoimmune diseases and the risk of bladder cancer: A Mendelian randomization analysis

OBJECTIVE

To investigate the association between autoimmune diseases (AIDs) and bladder cancer (BC) at the genetic level using Mendelian randomization (MR).

METHODS

Single nucleotide polymorphisms (SNPs) associated with the seven AIDs were extracted from the IEU GWAS database, and the SNPs were quality-controlled using strict screening criteria. The association between AIDs and BC risk was assessed by inverse-variance weighted (IVW), MR-Egger regression and Weighted median method. The heterogeneity of SNPs was evaluated by Cochran Q test. MR-Egger intercept test and MR-PRESSO global test were used to test the horizontal pleiotropy of SNPs. Both sides with potential causal associations were validated using the validation set.

RESULTS

Our result showed that genetically predicted RA was significantly associated with an increased risk of BC (IVW OR = 1.214, 95 % CI = 1.062-1.388, P = 0.005). MS nominally increased the risk of BC (IVW OR = 1.095, 95 % CI = 1.005-1.193, P = 0.037), consistent with the results of the MR analysis of the BC validation cohort. However SLE, T1D, UC, CD, and MG were not causally associated with BC risk (P > 0.05). The sensitivity analyses showed that there was no heterogeneity or horizontal pleiotropy in our findings.

CONCLUSION

This study provides evidence of a causal relationship between AIDs and BC risk at the genetic level, confirming a causal relationship between RA and MS in increasing the risk of BC.

Preparation and application of fluorescent monoclonal antibodies recognizing goat CD4+CD25+ regulatory T cells

Regulatory T cells (Tregs) are a subset of T cells participating in a variety of diseases including mycoplasmal pneumonia, contagious ecthyma, and so on. The role of Tregs in goat contagious ecthyma is not completely understood due to the lack of species-specific antibodies. Here, we developed a combination of CD4 and CD25 fluorescence monoclonal antibodies (mAb) to recognize goat Tregs and assessed its utility in flow cytometry, immunofluorescence staining. Using immunofluorescence staining, we found that the frequency of Treg cells was positively correlated with the viral load during orf virus infection. These antibodies could serve as important tools to monitor Tregs during orf virus infection in goats. KEY POINTS: • A combination of fluorescent mAbs (C11 and D12) was prepared for the detection of goat Tregs. • C11 and D12 are effective in flow cytometry, immunofluorescence staining, and C11 has excellent species specificity. • The frequency of Treg cells was positively correlated with the viral load during orf virus infection.

Th17/1 and ex-Th17 cells are detected in patients with polyarticular juvenile arthritis and increase following treatment

BACKGROUND

A better understanding of the pathogenesis of polyarticular juvenile idiopathic arthritis (polyJIA) is needed to aide in the development of data-driven approaches to guide selection between therapeutic options. One inflammatory pathway of interest is JAK-STAT signaling. STAT3 is a transcription factor critical to the differentiation of inflammatory T helper 17 cells (Th17s). Previous studies have demonstrated increased STAT3 activation in adult patients with rheumatoid arthritis, but less is known about STAT3 activation in polyJIA. We hypothesized that Th17 cells and STAT3 activation would be increased in treatment-naïve polyJIA patients compared to pediatric controls.

METHODS

Blood from 17 patients with polyJIA was collected at initial diagnosis and again if remission was achieved (post-treatment). Pediatric healthy controls were also collected. Peripheral blood mononuclear cells were isolated and CD4 + T cell subsets and STAT activation (phosphorylation) were evaluated using flow cytometry. Data were analyzed using Mann-Whitney U and Wilcoxon matched-pairs signed rank tests.

RESULTS

Treatment-naïve polyJIA patients had increased Th17 cells (CD3 + CD4 + interleukin(IL)-17 +) compared to controls (0.15% v 0.44%, p < 0.05), but Tregs (CD3 + CD4 + CD25 + FOXP3 +) from patients did not differ from controls. Changes in STAT3 phosphorylation in CD4 + T cells following ex vivo stimulation were not significantly different in patients compared to controls. We identified dual IL-17 + and interferon (IFN)γ + expressing CD4 + T cells in patients, but not controls. Further, both Th17/1 s (CCR6 + CD161 + IFNγ + IL-17 +) and ex-Th17s (CCR6 + CD161 + IFNγ + IL-17neg) were increased in patients' post-treatment (Th17/1: 0.3% v 0.07%, p < 0.05 and ex-Th17s: 2.3% v 1.4%, p < 0.05). The patients with the highest IL-17 expressing cells post-treatment remained therapy-bound.

CONCLUSIONS

Patients with polyJIA have increased baseline Th17 cells, potentially reflecting higher tonic STAT3 activation in vivo. These quantifiable immune markers may identify patients that would benefit upfront from pathway-focused biologic therapies. Our data also suggest that inflammatory CD4 + T cell subsets not detected in controls but increased in post-treatment samples should be further evaluated as a tool to stratify patients in remission on medication. Future work will explore these proposed diagnostic and prognostic biomarkers.

Rosa roxburghii Tratt juice inhibits NF-κB and increases IL-2 to alleviates the Foxp3-mediated Tregs imbalance in the peripheral blood of arseniasis patients

Arsenic can cause immune inflammation, which is the basis of arsenic-induced damage to multiple organs and systems. Forkhead box P3 (Foxp3)-labelled CD4+CD25+ regulatory T cells (Tregs) play an essential role in maintaining immune homeostasis. Nuclear factor-κb (NF-κB) and Interleukin-2 (IL-2) are critical regulators of Foxp3. Rosa roxburghii Tratt (RRT) is an edible medicinal plant with anti-inflammation effects. In this study, a control group (n = 41) and an arseniasis group (n = 209) were recruited, and screened subjects from the arseniasis patients for RRTJ (n = 46) or placebo (n = 43) to explore the possible mechanism by which RRT alleviates immune inflammation. The results indicated that RRTJ can inhibits NF-κB and increases IL-2, and alleviates the Foxp3-mediated Tregs imbalance in the peripheral blood of arseniasis patients. In summary, these findings suggest a novel intervention or therapeutic target for immune inflammation in arseniasis patients and provide new evidence that RRTJ inhibits immune inflammation.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01384-0.

Advances in reprogramming of energy metabolism in tumor T cells

Cancer is a leading cause of human death worldwide, and the modulation of the metabolic properties of T cells employed in cancer immunotherapy holds great promise for combating cancer. As a crucial factor, energy metabolism influences the activation, proliferation, and function of T cells, and thus metabolic reprogramming of T cells is a unique research perspective in cancer immunology. Special conditions within the tumor microenvironment and high-energy demands lead to alterations in the energy metabolism of T cells. In-depth research on the reprogramming of energy metabolism in T cells can reveal the mechanisms underlying tumor immune tolerance and provide important clues for the development of new tumor immunotherapy strategies as well. Therefore, the study of T cell energy metabolism has important clinical significance and potential applications. In the study, the current achievements in the reprogramming of T cell energy metabolism were reviewed. Then, the influencing factors associated with T cell energy metabolism were introduced. In addition, T cell energy metabolism in cancer immunotherapy was summarized, which highlighted its potential significance in enhancing T cell function and therapeutic outcomes. In summary, energy exhaustion of T cells leads to functional exhaustion, thus resulting in immune evasion by cancer cells. A better understanding of reprogramming of T cell energy metabolism may enable immunotherapy to combat cancer and holds promise for optimizing and enhancing existing therapeutic approaches.

Low vitamin D during pregnancy is associated with infantile eczema by up-regulation of PI3K/AKT/mTOR signaling pathway and affecting FOXP3 expression: A bidirectional cohort study

Vitamin D has received increasing attention because of its association with atopic disease development. Limited studies that have been done on the impact of maternal vitamin D levels during pregnancy on infantile eczema are still debatable. We wanted to discover the effect of maternal vitamin D on infantile eczema and explore whether regulatory T cells (Treg) play a role in this process. 219 pairs of mothers and children were enrolled. Maternal fasting venous blood was collected in pregnancy's second and third trimesters to determine vitamin D levels. Cord blood and placenta samples were collected during childbirth for detecting levels of genes, proteins and cytokines. Pediatricians followed up the prevalence of eczema in infants within 1 year. The reported rate of vitamin D deficiency and insufficiency was 35.6% and 28.3%. Lower maternal 25(OH)D3 levels were related to a higher risk of infantile eczema. Foxp3 gene expression is lower in cord blood of infants with eczema compared to infants without eczema. There was a positive correlation between maternal 25(OH)D3 levels and the expression of FOXP3 gene in cord blood. Compared to vitamin D sufficiency women, vitamin D deficiency women's placental FOXP3 protein expression was decreased and PI3K/AKT/mTOR protein was up-regulated. Our study demonstrates that low prenatal maternal vitamin D levels increased the risk of infantile eczema aged 0-1 year, which might be related to the downregulating of the FOXP3 gene expression in cord blood and decreased placental FOXP3 protein expression. Low placental FOXP3 protein was related with activating PI3K/AKT/mTOR signaling pathway.

Myeloid and lymphoid expression of C9orf72 regulates IL-17A signaling in mice

A mutation in C9ORF72 is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Patients with ALS or FTD often develop autoimmunity and inflammation that precedes or coincides with the onset of neurological symptoms, but the underlying mechanisms are poorly understood. Here, we knocked out murine C9orf72 in seven hematopoietic progenitor compartments by conditional mutagenesis and found that myeloid lineage C9orf72 prevents splenomegaly, loss of tolerance, and premature mortality. Furthermore, we demonstrated that C9orf72 plays a role in lymphoid cells to prevent interleukin-17A (IL-17A) production and neutrophilia. Mass cytometry identified early and sustained elevation of the costimulatory molecule CD80 expressed on C9orf72-deficient mouse macrophages, monocytes, and microglia. Enrichment of CD80 was similarly observed in human spinal cord microglia from patients with C9ORF72-mediated ALS compared with non-ALS controls. Single-cell RNA sequencing of murine spinal cord, brain cortex, and spleen demonstrated coordinated induction of gene modules related to antigen processing and presentation and antiviral immunity in C9orf72-deficient endothelial cells, microglia, and macrophages. Mechanistically, C9ORF72 repressed the trafficking of CD80 to the cell surface in response to Toll-like receptor agonists, interferon-γ, and IL-17A. Deletion of Il17a in C9orf72-deficient mice prevented CD80 enrichment in the spinal cord, reduced neutrophilia, and reduced gut T helper type 17 cells. Last, systemic delivery of an IL-17A neutralizing antibody augmented motor performance and suppressed neuroinflammation in C9orf72-deficient mice. Altogether, we show that C9orf72 orchestrates myeloid costimulatory potency and provide support for IL-17A as a therapeutic target for neuroinflammation associated with ALS or FTD.

Regulatory T cells in spondyloarthropathies: genetic evidence, functional role, and therapeutic possibilities

Regulatory T cells (Tregs) are a very specialized subset of T lymphocytes: their main function is controlling immune responses during inflammation. T-regs involvement in autoimmune and immune-mediated rheumatic diseases is well-described. Here, we critically review the up-to-date literature findings on the role of Tregs in spondyloarthropathies, particularly in ankylosing spondylitis (AS), a polygenic inflammatory rheumatic disease that preferentially affects the spine and the sacroiliac joints. Genetics discoveries helped in elucidating pathogenic T-regs gene modules and functional involvement. We highlight T-regs tissue specificity as crucial point, as T-regs might have a distinct epigenomic and molecular profiling depending on the different site of tissue inflammation. Furthermore, we speculate about possible therapeutic interventions targeting, or enhancing, Treg cells in spondyloarthropathies.

Gene expression profile of immune-check point in response to Trastuzumab therapy in patients with HER-2 positive breast cancer

OBJECTIVE

Aim: To clarify the association between response to Trastuzumab and molecular expression of TIM-3 and FOXP-3 immune checkpoints.

PATIENTS AND METHODS

Materials and Methods: FOXP-3 and TIM-3 expression in peripheral blood was analyzed using qPCR, and the serum level of Trastuzumab was estimated using an immune sorbent enzyme assay.

RESULTS

Results: During treatment with Trastuzumab, the FOXP-3 gene expression showed a significant decline throughout one year of treatment, going from 0.85 at cycle 9 to 0.75 at cycle 17. While the TIM-3 gene expression showed a significant up regulation at cycle 9 to 2.8 fold, followed by a reduction in the fold change from 2.8 to 1.7 in the font of reference gene expression.

CONCLUSION

Conclusions:FOXP-3 and TIM-3 have the potential to be suggestive markers that can anticipate the response to Trastuzumab, but they are not capable of predicting the likelihood of recurrence.

Promises and Pitfalls of Next-Generation Treg Adoptive Immunotherapy

Regulatory T cells (Tregs) are fundamental to maintaining immune homeostasis by inhibiting immune responses to self-antigens and preventing the excessive activation of the immune system. Their functions extend beyond immune surveillance and subpopulations of tissue-resident Treg cells can also facilitate tissue repair and homeostasis. The unique ability to regulate aberrant immune responses has generated the concept of harnessing Tregs as a new cellular immunotherapy approach for reshaping undesired immune reactions in autoimmune diseases and allo-responses in transplantation to ultimately re-establish tolerance. However, a number of issues limit the broad clinical applicability of Treg adoptive immunotherapy, including the lack of antigen specificity, heterogeneity within the Treg population, poor persistence, functional Treg impairment in disease states, and in vivo plasticity that results in the loss of suppressive function. Although the early-phase clinical trials of Treg cell therapy have shown the feasibility and tolerability of the approach in several conditions, its efficacy has remained questionable. Leveraging the smart tools and platforms that have been successfully developed for primary T cell engineering in cancer, the field has now shifted towards "next-generation" adoptive Treg immunotherapy, where genetically modified Treg products with improved characteristics are being generated, as regards antigen specificity, function, persistence, and immunogenicity. Here, we review the state of the art on Treg adoptive immunotherapy and progress beyond it, while critically evaluating the hurdles and opportunities towards the materialization of Tregs as a living drug therapy for various inflammation states and the broad clinical translation of Treg therapeutics.

TIGIT reverses IFN-α-promoted Th1-like Tregs via in-sequence effects dependent on STAT4

OBJECTIVES

The induction direction of interferon (IFN)-α in T-cell phenotype and function varies depending on the activation state of the cell and the time of stimulation. To assess the effects of elevated IFN-α on regulatory T cells (Tregs) in systemic lupus erythematosus (SLE) patients, we investigated the differentiation of Th1-like Tregs under in-sequence and out-of-sequence conditions and the reversal effect of activating TIGIT on immune suppression.

METHODS

Phenotypes and activation levels of Tregs from SLE patients and healthy controls were analyzed using flow cytometry. In vitro culture conditions based on the sequence of TCR activation and IFN-α stimulation simulated in-sequence or out-of-sequence effects. CD4+T cells and Tregs were cultured under the above conditions with or without TIGIT agonist. Expression of related characteristic markers and phosphorylation levels of AKT, mTOR, and STATs were detected using flow cytometry and ELISA.

RESULTS

The frequency of Th1-like Tregs and activation levels of Tregs increased, but TIGIT expression in Tregs decreased in SLE patients. IFN-α promoted the conversation of Tregs to Th1-like Tregs while reducing immunosuppressive function under in-sequence conditions. The STAT4 pathway, but not the STAT1 pathway, was crucial for the IFN-α-mediated in-sequence effects. Reactivation of TIGIT reversed Th1 polarization of Tregs by suppressing AKT/mTOR and STAT4 signaling.

CONCLUSIONS

Our findings suggest that IFN-α mediated in-sequence effects on Tregs may be responsible for the expansion of Th1-like Tregs in SLE. TIGIT can restore immune suppression damage in Tregs and represents a potential therapeutic target for SLE.

Long-term consequences of regulatory T-cell-specific knockout of Notch2 in immune homeostasis

AIMS

To investigate the long-term alterations in immune function and spontaneous inflammation in mice following specific knockout of Notch2 (Notch2KO) in Treg cells.

MAIN METHODS

A Treg cell-specific Notch2 knockout mouse model was constructed, and the mice were named Notch2KO mice. The pathological changes and inflammatory cell infiltration in the lungs, skin, and liver of the mice at 2, 6, 9, and 12 months of age were evaluated by HE staining. The expression of Th1/Th2/Th17/Treg transcription factors was detected by Western blotting. The proportion of CD4 + T-cell subsets was determined by flow cytometry. The levels of Th1/Th2/Th17/Treg cytokines were measured by enzyme-linked immunosorbent assays (ELISAs).

KEY FINDINGS

The expression level of Notch2 in Treg cells from the Notch2KO mice was significantly decreased compared with that in Treg cells from the control mice (P < 0.05). HE staining showed that compared with the control mice, the Notch2KO mice displayed spontaneous inflammation and had a large amount of inflammatory cell infiltration in the lungs and skin (P < 0.05). The number of Treg cells, the expression level of Foxp3, and the level of IL-10 were reduced in the Notch2KO mice compared with the control mice (P < 0.05), and these metrics further decreased with increasing age (P < 0.05). In contrast, the number of Th1/Th2 cells, the expression level of T-bet/GATA3, and the levels of Th1 cytokines (IFN-γ)/Th2 cytokines (IL-4, IL-5, and IL-13) were significantly increased in the Notch2KO mice (P < 0.05), and these metrics further increased with increasing age (P < 0.05). There was no significant change in the number of Th17 cells, the expression of RORγt, or the level of IL-17. Further analysis showed that the balance of Th1/Th2 and Treg/Th17 cells in the Notch2KO mice was shifted, and the ratio showed a downward trend over time (P < 0.05).

SIGNIFICANCE

The number and function of Treg cells can be severely inhibited by a specific knockout of Notch2 in Treg cells, leading to immune disorders that gradually worsen over time.

Identification of human exTreg cells as CD16+CD56+ cytotoxic CD4+ T cells

In atherosclerosis, some regulatory T (Treg) cells become exTreg cells. We crossed inducible Treg and exTreg cell lineage-tracker mice (FoxP3eGFP-Cre-ERT2ROSA26CAG-fl-stop-fl-tdTomato) to atherosclerosis-prone Apoe-/- mice, sorted Treg cells and exTreg cells and determined their transcriptomes by bulk RNA sequencing (RNA-seq). Genes that were differentially expressed between mouse Treg cells and exTreg cells and filtered for their presence in a human single-cell RNA-sequencing (scRNA-seq) panel identified exTreg cell signature genes as CST7, NKG7, GZMA, PRF1, TBX21 and CCL4. Projecting these genes onto the human scRNA-seq with CITE-seq data identified human exTreg cells as CD3+CD4+CD16+CD56+, which was validated by flow cytometry. Bulk RNA-seq of sorted human exTreg cells identified them as inflammatory and cytotoxic CD4+T cells that were significantly distinct from both natural killer and Treg cells. DNA sequencing for T cell receptor-β showed clonal expansion of Treg cell CDR3 sequences in exTreg cells. Cytotoxicity was functionally demonstrated in cell killing and CD107a degranulation assays, which identifies human exTreg cells as cytotoxic CD4+T cells.

Immunological mechanisms of inflammatory diseases caused by gut microbiota dysbiosis: A review

The gut microbiota is indispensable for maintaining host health by enhancing the host's digestive capacity, safeguarding the intestinal epithelial barrier, and preventing pathogen invasion. Additionally, the gut microbiota exhibits a bidirectional interaction with the host immune system and promotes the immune system of the host to mature. Dysbiosis of the gut microbiota, primarily caused by factors such as host genetic susceptibility, age, BMI, diet, and drug abuse, is a significant contributor to inflammatory diseases. However, the mechanisms underlying inflammatory diseases resulting from gut microbiota dysbiosis lack systematic categorization. In this study, we summarize the normal physiological functions of symbiotic microbiota in a healthy state and demonstrate that when dysbiosis occurs due to various external factors, the normal physiological functions of the gut microbiota are lost, leading to pathological damage to the intestinal lining, metabolic disorders, and intestinal barrier damage. This, in turn, triggers immune system disorders and eventually causes inflammatory diseases in various systems. These discoveries provide fresh perspectives on how to diagnose and treat inflammatory diseases. However, the unrecognized variables that might affect the link between inflammatory illnesses and gut microbiota, need further studies and extensive basic and clinical research will still be required to investigate this relationship in the future.

T cells in health and disease

T cells are crucial for immune functions to maintain health and prevent disease. T cell development occurs in a stepwise process in the thymus and mainly generates CD4+ and CD8+ T cell subsets. Upon antigen stimulation, naïve T cells differentiate into CD4+ helper and CD8+ cytotoxic effector and memory cells, mediating direct killing, diverse immune regulatory function, and long-term protection. In response to acute and chronic infections and tumors, T cells adopt distinct differentiation trajectories and develop into a range of heterogeneous populations with various phenotype, differentiation potential, and functionality under precise and elaborate regulations of transcriptional and epigenetic programs. Abnormal T-cell immunity can initiate and promote the pathogenesis of autoimmune diseases. In this review, we summarize the current understanding of T cell development, CD4+ and CD8+ T cell classification, and differentiation in physiological settings. We further elaborate the heterogeneity, differentiation, functionality, and regulation network of CD4+ and CD8+ T cells in infectious disease, chronic infection and tumor, and autoimmune disease, highlighting the exhausted CD8+ T cell differentiation trajectory, CD4+ T cell helper function, T cell contributions to immunotherapy and autoimmune pathogenesis. We also discuss the development and function of γδ T cells in tissue surveillance, infection, and tumor immunity. Finally, we summarized current T-cell-based immunotherapies in both cancer and autoimmune diseases, with an emphasis on their clinical applications. A better understanding of T cell immunity provides insight into developing novel prophylactic and therapeutic strategies in human diseases.

T cells: an emerging cast of roles in bipolar disorder

Bipolar disorder (BD) is a distinctly heterogeneous and multifactorial disorder with a high individual and social burden. Immune pathway dysregulation is an important pathophysiological feature of BD. Recent studies have suggested a potential role for T lymphocytes in the pathogenesis of BD. Therefore, greater insight into T lymphocytes' functioning in patients with BD is essential. In this narrative review, we describe the presence of an imbalance in the ratio and altered function of T lymphocyte subsets in BD patients, mainly in T helper (Th) 1, Th2, Th17 cells and regulatory T cells, and alterations in hormones, intracellular signaling, and microbiomes may be potential causes. Abnormal T cell presence explains the elevated rates of comorbid inflammatory illnesses in the BD population. We also update the findings on T cell-targeting drugs as potentially immunomodulatory therapeutic agents for BD disease in addition to classical mood stabilizers (lithium, valproic acid). In conclusion, an imbalance in T lymphocyte subpopulation ratios and altered function may be involved in the development of BD, and maintaining T cell immune homeostasis may provide an overall therapeutic benefit.

Interleukin-6 neutralization and regulatory T cells are additive in chondroprotection from IL-1β-induced inflammation

Anti-inflammatory Regulatory T cells (Tregs) are enriched in the joints of patients with osteoarthritis (OA) compared to healthy joints. Tregs maintain homeostasis through secretion of anti-inflammatory cytokines and cell-to-cell interactions including immune checkpoint signaling. Interleukin-6 (IL-6) is a pleiotropic cytokine secreted by inflamed synoviocytes and chondrocytes that can inhibit or alter Treg function. This study tested the hypothesis that neutralization of IL-6 would enable Treg anti-inflammatory function to resolve inflammation and catabolism elicited by IL-1β in an equine chondrocyte/synoviocyte/Treg tri-culture OA model. Synoviocyte/chondrocyte co-cultures were stimulated with IL-1β, and treated with αIL-6 neutralizing antibody. Activated Tregs secreting IL-10 were added in direct contact with synoviocytes to create a tri-culture. Neutralization of IL-6 partially restored Treg anti-inflammatory functions and, in combination, reduced IL-1β-stimulated synoviocyte MMP13 expression to control levels and restored Acan expression in chondrocytes. IL-6 neutralization alone decreased Il6 expression in chondrocytes and synoviocytes, mitigating IL-6 positive feedback loop. Although Tregs were the primary producers of anti-inflammatory IL-10 and IL-4, they also produced pro-inflammatory IL-17A, as detected by ELIA, which may have been responsible for incomplete rescue of synoviocyte/chondrocyte homeostasis following IL-1β stimulation. Treg secretion of IL-10, IL-4, and IL-17A was not altered by tri-culture conditions or presence of αIL-6, therefore, it was unlikely that Treg phenotype instability occurred. The significant effect of chondrocyte/synoviocyte donor, but not Treg donor, on gene expression and IL-6 concentration in conditioned media, indicated that personalized therapy considering the patient's OA status might be needed for successful implementation of immunotherapy in the context of OA.

Promoted Generation of T Helper 1-Like Regulatory T Cells After Transient Middle Cerebral Artery Occlusion in Type-2 Diabetic Mice

BACKGROUND

Regulatory T cells (Tregs) play a remarkable role in modulating post-ischemic neuroinflammation. However, the characteristics of Tregs in diabetic ischemic stroke remain unknown.

METHODS

Transient middle cerebral artery occlusion (MCAO) was conducted on leptin receptor-mutated db/db mice and db/+ mice. The number, cytokine production, and signaling features of Tregs in peripheral blood and ipsilateral hemispheres were evaluated by flow cytometry. Treg plasticity was assessed by the adoptive transfer of splenic Tregs into mice. The effect of ipsilateral macrophages/microglia on Treg plasticity was determined by in vitro co-culture analysis.

RESULTS

db/db mice had more infiltrating Tregs in their ipsilateral hemispheres than db/+ mice. Infiltrating Tregs in db/db mice expressed higher transforming growth factor-β (TGF-β), interleukin-10 (IL-10), forkhead box P3 (Foxp3), interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and T-box expressed in T cells (T-bet) in comparison to infiltrating Tregs in db/+ mice, suggesting promoted generation of T helper 1 (Th1)-like Tregs in the brains of db/db mice after stroke. The post-ischemic brain microenvironment of db/db mice significantly up-regulated IFN-γ, TNF-α, T-bet, IL-10, and TGF-β in infiltrating Tregs. Moreover, ipsilateral macrophages/microglia remarkably enhanced the expression of IFN-γ, TNF-α, and T-bet but not IL-10 and TGF-β in Tregs. db/db macrophages/microglia were more potent in up-regulating IFN-γ, TNF-α, and T-bet than db/+ macrophages/microglia. Interleukin-12 (IL-12) blockage partially abolished the modulatory effect of macrophages/microglia on Tregs.

CONCLUSION

The generation of Th1-like Tregs was promoted in the brains of type 2 diabetic mice after stroke. Our study reveals significant Treg plasticity in diabetic stroke.Abbreviations: Foxp3: forkhead box P3; IFN-γ: interferon-γ; IL-10: interleukin-10; IL-12: interleukin-12; MCAO: middle cerebral artery occlusion; PBS: phosphate-buffered saline; STAT1: Signal transducer and activator of transcription 1; STAT5: Signal transducer and activator of transcription 1; T-bet: T-box expressed in T cells; TGF-β: transforming growth factor-β; Th1: T helper 1; TNF-α: tumor necrosis factor-α; Tregs: regulatory T cells. Foxp3: forkhead box P3; IFN-γ: interferon-γ; IL-10: interleukin-10; IL-12: interleukin-12; MCAO: middle cerebral artery occlusion; PBS: phosphate-buffered saline; STAT1: Signal transducer and activator of transcription 1; STAT5: Signal transducer and activator of transcription 1; T-bet: T-box expressed in T cells; TGF-β: transforming growth factor-β; Th1: T helper 1; TNF-α: tumor necrosis factor-α; Tregs: regulatory T cells.

Autoimmunity and Carcinogenesis: Their Relationship under the Umbrella of Autophagy

The immune system and autophagy share a functional relationship. Both innate and adaptive immune responses involve autophagy and, depending on the disease’s origin and pathophysiology, it may have a detrimental or positive role on autoimmune disorders. As a “double-edged sword” in tumors, autophagy can either facilitate or impede tumor growth. The autophagy regulatory network that influences tumor progression and treatment resistance is dependent on cell and tissue types and tumor stages. The connection between autoimmunity and carcinogenesis has not been sufficiently explored in past studies. As a crucial mechanism between the two phenomena, autophagy may play a substantial role, though the specifics remain unclear. Several autophagy modifiers have demonstrated beneficial effects in models of autoimmune disease, emphasizing their therapeutic potential as treatments for autoimmune disorders. The function of autophagy in the tumor microenvironment and immune cells is the subject of intensive study. The objective of this review is to investigate the role of autophagy in the simultaneous genesis of autoimmunity and malignancy, shedding light on both sides of the issue. We believe our work will assist in the organization of current understanding in the field and promote additional research on this urgent and crucial topic.

MicroRNA-143-3p ameliorates collagen-induced arthritis by polarizing naive CD4+ T cells into Treg cells

BACKGROUND

Rheumatoid arthritis (RA) is a persistent and systemic autoimmunity disease. The abnormal differentiation of Treg cells is important in pathogenesis. Despite previous studies showed that microRNAs (miRNAs, miR) are pivotal modulators of Treg cells, the effect of miRNAs on Treg cell differentiation and function is not clear. Our study wants to reveal the relationship of miR-143-3p with the differentiative ability and biofunction of Treg cells during the development of RA.

METHODS

The Expressing level of miR-143-3p and cell factor generation in peripheral blood (PB) of RA sufferers were identified by ELISA or RT-qPCR. The roles of miR-143-3p in Treg cell differentiation were studied via ShRNA/lentivirus transfection. Male DBA/1 J mice were separated into control, model, control mimics, and miR-143-3p mimics groups to analyze the anti-arthritis efficacy, the differentiative ability of Treg cells, and the expression level of miR-143-3p.

RESULTS

Our team discovered that the Expressing level of miR-143-3p was related to RA disease activities in a negative manner, and remarkably related to antiinflammation cell factor IL-10. In vitro, the expression of miR-143-3p in the CD4⁺ T cells upregulated the percentage of CD4⁺ CD25⁺ Fxop3⁺ cells (Tregs) and forkhead box protein 3 (Foxp3) mRNA expression. Evidently, miR-143-3p mimic intervention considerably upregulated the content of Treg cells in vivo, validly avoided CIA progression, and remarkably suppressed the inflammatory events of joints in mice.

CONCLUSION

Our findings indicated that miR-143-3p could ameliorate CIA through polarizing naive CD4⁺ T cells into Treg cells, which may be a novel strategy to treat autoimmune diseases such as RA.

Innate and adaptive immune abnormalities underlying autoimmune diseases: the genetic connections

With the exception of an extremely small number of cases caused by single gene mutations, most autoimmune diseases result from the complex interplay between environmental and genetic factors. In a nutshell, etiology of the common autoimmune disorders is unknown in spite of progress elucidating certain effector cells and molecules responsible for pathologies associated with inflammatory and tissue damage. In recent years, population genetics approaches have greatly enriched our knowledge regarding genetic susceptibility of autoimmunity, providing us with a window of opportunities to comprehensively re-examine autoimmunity-associated genes and possible pathways. In this review, we aim to discuss etiology and pathogenesis of common autoimmune disorders from the perspective of human genetics. An overview of the genetic basis of autoimmunity is followed by 3 chapters detailing susceptibility genes involved in innate immunity, adaptive immunity and inflammatory cell death processes respectively. With such attempts, we hope to expand the scope of thinking and bring attention to lesser appreciated molecules and pathways as important contributors of autoimmunity beyond the 'usual suspects' of a limited subset of validated therapeutic targets.

Radiolabelling of Polyclonally Expanded Human Regulatory T Cells (Treg) with 89Zr-oxine for Medium-Term In Vivo Cell Tracking

Regulatory T cells (Tregs) are a promising candidate cell therapy to treat autoimmune diseases and aid the longevity of transplanted solid organs. Despite increasing numbers of clinical trials using human Treg therapy, important questions pertaining to their in vivo fate, distribution, and function remain unanswered. Treg accumulation in relevant tissues was found to be crucial for Treg therapy efficacy, but existing blood-borne biomarkers are unlikely to accurately reflect the tissue state. Non-invasive Treg tracking by whole-body imaging is a promising alternative and can be achieved by direct radiolabelling of Tregs and following the radiolabelled cells with positron emission tomography (PET). Our goal was to evaluate the radiolabelling of polyclonal Tregs with 89Zr to permit their in vivo tracking by PET/CT for longer than one week with current preclinical PET instrumentation. We used [89Zr]Zr(oxinate)4 as the cell-labelling agent and achieved successful radiolabelling efficiency of human Tregs spanning 0.1-11.1 Bq 89Zr/Treg cell, which would be compatible with PET tracking beyond one week. We characterized the 89Zr-Tregs, assessing their phenotypes, and found that they were not tolerating these intracellular 89Zr amounts, as they failed to survive or expand in a 89Zr-dose-dependent manner. Even at 0.1 Bq 89Zr per Treg cell, while 89Zr-Tregs remained functional as determined by a five-day-long effector T cell suppression assay, they failed to expand beyond day 3 in vitro. Moreover, PET imaging revealed signs of 89Zr-Treg death after adoptive transfer in vivo. In summary, 89Zr labelling of Tregs at intracellular radioisotope amounts compatible with cell tracking over several weeks did not achieve the desired outcomes, as 89Zr-Tregs failed to expand and survive. Consequently, we conclude that indirect Treg labelling is likely to be the most effective alternative method to satisfy the requirements of this cell tracking scenario.

Acupuncture regulates the Th17/Treg balance and improves cognitive deficits in a rat model of vascular dementia

Objective

The present study was developed to explore the impact of acupuncture on the Th17/Treg balance in the brain and the periphery and associated changes in cognitive deficits in a rat model of vascular dementia (VD).

Methods

Male Wistar rats (8 weeks old) were randomly assigned to sham-operated (Gs, n = 10), and operation (n = 30) groups. A VD model was established for all rats in the operation group via the permanent bilateral occlusion of the common carotid artery. Behavioral screening of these rats was conducted via a hidden platform trial at 2 months post-operation. These operation group rats were then further subdivided into impaired (Gi) and acupuncture (Ga) groups (n = 10/group). Acupuncture was performed over a 21-day period for rats in the Ga group. A Morris water maze (MWM) test was used to assess cognitive function for rats in all groups. Flow cytometry and fluorescent staining were used to detect Th17 and Treg cells in samples from these animals based on IL-17/FoxP3 or CD4+FoxP3+/CD4+RORγt+ staining profiles.

Results

Relative to the Gs group, escape latency values for rats in the Gi group were significantly increased. Following treatment, rats in the Ga group exhibited significant reductions in escape latency values as compared to rats in the Gi group (P < 0.05). The relative Treg proportion in the peripheral blood and spleen additionally trended upwards in these Ga rats as compared to those in the Gi group (P > 0.05), whereas the frequency of Th17 cells in the peripheral blood and spleen of Ga group rats trended downward relative to the Gi group (P > 0.05). Significantly fewer CD4+RORγt+ and RORγt+ cells were detected in the Ga group relative to the Gi group, whereas CD4+FoxP3+ and FoxP3+ cell counts were increased (P < 0.01).

Conclusion

In summary, VD model rats exhibited dysregulated Th17/Treg homeostasis. Acupuncture treatment was sufficient to reduce the frequency and numbers of Th17 cells in these animals while increasing Treg cell levels, thereby alleviating cognitive deficits with respect to both spatial learning and memory impairment. Consequently, the therapeutic benefits of such acupuncture treatment may be attributable to the regulation of the Th17/Treg balance and associated improvements in cognitive function.

Th17 Cells: Orchestrators of Mucosal Inflammation and Potential Therapeutic Targets

T helper 17 (Th17) cells represent a specialized subgroup of effector CD4+ T cells known for their role in provoking neutrophil-driven tissue inflammation, particularly within mucosal tissues. Although they are pivotal for defending the host against extracellular bacteria and fungi, they have also been associated with development of various T cell-mediated inflammatory conditions, autoimmune diseases, and even cancer. Notably, Th17 cells exhibit a dual nature, with different Th17 cell subtypes showcasing distinct effector functions and varying capacities to incite autoimmune tissue inflammation. Furthermore, Th17 cells exhibit significant plasticity, which carries important functional implications, both in terms of their expression of cytokines typically associated with other effector T cell subsets and in their interactions with regulatory CD4+ T cells. The intricate balance of Th17 cytokines can also be a double-edged sword in inflammation, autoimmunity, and cancer. Within this article, we delve into the mechanisms that govern the differentiation, function, and adaptability of Th17 cells. We culminate with an exploration of therapeutic potentials in harnessing the power of Th17 cells and their cytokines. Targeted interventions to modulate Th17 responses are emerging as promising strategies for autoimmunity, inflammation, and cancer treatment. By precisely fine-tuning Th17-related pathways, we may unlock new avenues for personalized therapeutic approaches, aiming to restore immune balance, alleviate the challenges of these disorders, and ultimately enhance the quality of life for individuals affected by them.

Splicing factor SRSF1 controls autoimmune-related molecular pathways in regulatory T cells distinct from FoxP3

Regulatory T cells (Tregs) are vital for maintaining immune self-tolerance, and their impaired function leads to autoimmune disease. Mutations in FoxP3, the master transcriptional regulator of Tregs, leads to immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome in humans and the early lethal "scurfy" phenotype with multi-organ autoimmune disease in mice. We recently identified serine/arginine-rich splicing factor 1 (SRSF1) as an indispensable regulator of Treg homeostasis and function. Intriguingly, Treg-conditional SRSF1-deficient mice exhibit early lethal systemic autoimmunity with multi-organ inflammation reminiscent of the scurfy mice. Importantly, SRSF1 is decreased in T cells from patients with the autoimmune disease systemic lupus erythematosus (SLE), and low SRSF1 levels inversely correlate with disease severity. Given that the Treg-specific deficiency of SRSF1 causes similarly profound autoimmune disease outcomes in mice as the deficiency/mutation in FoxP3, we aimed to evaluate the genes and molecular pathways controlled by these two indispensable regulatory proteins. We performed comparative bioinformatic analyses of transcriptomic profiles of Tregs from Srsf1-knockout mice and two Foxp3 mutant mice--the FoxP3-deficient ΔFoxp3 and the Foxp3 M370I mutant mice. We identified 132 differentially expressed genes (DEGs) unique to Srsf1-ko Tregs, 503 DEGs unique to Foxp3 M370I Tregs, and 1367 DEGs unique to ΔFoxp3 Tregs. Gene set enrichment and pathway analysis of DEGs unique to Srsf1-ko Tregs indicate that SRSF1 controls cytokine and immune response pathways. Conversely, FoxP3 controls pathways involved in DNA replication and cell cycle. Besides the distinct gene signatures, we identified only 30 shared genes between all three Treg mutants, mostly contributing to cytokine and immune defense pathways. Prominent genes included the chemokines CXCR6 and CCL1 and the checkpoint inhibitors FASLG and PDCD1. Thus, we demonstrate that SRSF1 and FoxP3 control common and distinct molecular pathways implicated in autoimmunity. Our analyses suggest that SRSF1 controls crucial immune functions in Tregs contributing to immune tolerance, and perturbations in its levels lead to systemic autoimmunity via mechanisms that are largely distinct from FoxP3.

Interleukin-23 receptor defines T helper 1-like regulatory T cells in oral squamous cell carcinoma

BACKGROUND

The immune responses play significant roles in the onset, progression, and outcome of oral squamous cell carcinoma (OSCC). CD4+ regulatory T cells (Tregs) significantly impact tumor immunity. However, their role in OSCC development remains elusive.

METHODS

In a carcinogen-induced mouse OSCC model, interleukin-23 receptor (IL-23R) expression on Tregs and Treg function were determined by flow cytometry. IL-23R overexpression in Tregs was achieved by lentiviral infection, followed by evaluation of the expression of Forkhead box P3 (Foxp3), T-bet, retineic-acid-receptor-related orphan nuclear receptor gamma t, and cytokines by flow cytometry. Adoptive transfer assays were applied to analyze the function of IL-23R- overexpressing Tregs in vivo. The cellular sources of IL-23 were also determined by flow cytometry.

RESULTS

IL-23R- Tregs and IL-23R+ Tregs were found in the tongues but not spleens of OSCC-bearing mice. IL-23R+ Tregs expressed lower Foxp3 but higher T-bet than IL-23R- Tregs. IL-23R- Tregs produced abundant IL-10 and transforming growth factor (TGF)-β, while IL-23R+ Tregs produced lower IL-10 and TGF-β but remarkably higher interferon (IFN)-γ. Furthermore, IL-23R+ Tregs possessed more phosphorylated signal transducer and activator of transcription (STAT3) and STAT4 than IL-23R- Tregs. IL-23R+ Tregs were less immunosuppressive than IL-23R- Tregs, as evidenced by weaker inhibition of activated conventional T cells. IL-23R overexpression in splenic Tregs remarkably reduced the expression of IL-10 and TGF-β but increased IFN-γ expression when Tregs were adoptively transferred into OSCC-bearing mice. In the OSCC microenvironment, macrophages, dendritic cells, and malignant OSCC cells produced IL-23 which might modulate the function of IL-23R+ Tregs.

CONCLUSIONS

This study unveils Treg heterogeneity, thus deepening the understanding of Treg biology and tumor immunity in OSCC.

Notch2-dependent GATA3+ Treg cells alleviate allergic rhinitis by suppressing the Th2 cell response

The aim of this study was to investigate the role and mechanism of Notch2-dependent GATA3+ Treg cells in allergic rhinitis (AR). Samples were collected from patients in the control and AR groups to detect differences in the numbers of GATA3+ Treg cells and their intracellular Notch2 levels. The effects of Notch2 on GATA3+ Treg cell differentiation and function in vitro were detected. AR mice were subjected to adoptive transfer of GATA3+ Treg cells to detect changes in the allergic inflammatory response and Th2 cells. Mice with Treg cell-specific knockout of Notch2 were constructed, and an AR model was established to detect the changes. The number of GATA3+ Treg cells and intracellular Notch2 expression in peripheral blood of the AR group were decreased compared with the controls (P < 0.05), and the number of GATA3+ Treg cells was significantly negatively correlated with the level of allergen-specific IgE (sIgE; P < 0.01). In vitro experiments showed that Notch2 promoted the differentiation and immunosuppressive function of GATA3+ Treg cells, and Notch2 directly promoted GATA3 transcription in Treg cells (P < 0.05). Animal experiments indicated that adoptive transfer of GATA3+ Treg cells reduced the allergic inflammatory response in AR mice (P < 0.05). The number of GATA3+ Treg cells was decreased in gene knockout mice (P < 0.05), and autoimmune inflammation was observed. After modeling, the allergic inflammatory response was further aggravated (P < 0.05). Overall, our findings indicate that Notch2 alleviates AR by specifically increasing GATA3+ Treg cell differentiation. Notch2 expressed in Treg cells is expected to be a new therapeutic target for AR.

EZH2: Its regulation and roles in immune disturbance of SLE

The pathogenesis of systemic lupus erythematosus (SLE) is related to immune homeostasis imbalance. Epigenetic mechanisms have played a significant role in breaking immune tolerance. Enhancer of zeste homolog 2 (EZH2), the specific methylation transferase of lysine at position 27 of histone 3, is currently found to participate in the pathogenesis of SLE through affecting multiple components of the immune system. This review mainly expounds the mechanisms underlying EZH2-mediated disruption of immune homeostasis in SLE patients, hoping to provide new ideas in the pathogenesis of SLE and new targets for future treatment.

Human chorionic gonadotropin promotes murine Treg cells and restricts pregnancy-harmful proinflammatory Th17 responses

An equilibrium between proinflammatory and anti-inflammatory immune responses is essential for maternal tolerance of the fetus throughout gestation. To study the participation of fetal tissue-derived factors in this delicate immune balance, we analyzed the effects of human chorionic gonadotropin (hCG) on murine Treg cells and Th17 cells in vitro, and on pregnancy outcomes, fetal and placental growth, blood flow velocities and remodeling of the uterine vascular bed in vivo. Compared with untreated CD4⁺CD25⁺ T cells, hCG increased the frequency of Treg cells upon activation of the LH/CG receptor. hCG, with the involvement of IL-2, also interfered with induced differentiation of CD4⁺ T cells into proinflammatory Th17 cells. In already differentiated Th17 cells, hCG induced an anti-inflammatory profile. Transfer of proinflammatory Th17 cells into healthy pregnant mice promoted fetal rejection, impaired fetal growth and resulted in insufficient remodeling of uterine spiral arteries, and abnormal flow velocities. Our works show that proinflammatory Th17 cells have a negative influence on pregnancy that can be partly avoided by in vitro re-programming of proinflammatory Th17 cells with hCG.

Allergen immunotherapy enhances the immunosuppressive effects of Treg cells to alleviate allergic rhinitis by decreasing PU-1+ Treg cell numbers

OBJECTIVE

To investigate the role of Tregs and their subtypes in the treatment of allergic rhinitis with allergen immunotherapy (AIT) as well as the underlying mechanism.

METHODS

1. Thirty-one healthy controls, 29 Allergic rhinitis (AR) patients and 16 AR patients treated with AIT were recruited. The total nasal symptom scores (TNSSs) were calculated. The serum levels of IgE, IL-2, TNF-α, IFN-γ, IL-4, IL-5, IL-6, IL-10 and IL-17 were measured. 2. Changes in the proportions of CD4+ T cells, Treg cells, Treg subtypes and Th1/Th2/Th9/Th17/Tfh cells in the peripheral blood of the subjects in the three groups were measured. 3. The correlations of Treg cells, Treg subtypes and TNSS with the levels of various cytokines in the AR group and AIT group were analysed.

RESULTS

1. Compared with the control group, the TNSS and IgE, IL-5 and IL-6 levels in the AR group were significantly increased, while the IL-2, IFN-γ and IL-10 levels were significantly decreased (P < 0.05). Compared with the AR group, the TNSS and IgE, IL-5 and IL-6 levels in the AIT group were significantly decreased, while the IL-2, IFN-γ and IL-10 levels were significantly increased (P < 0.05). 2. Compared with the control group, the proportions of Tregs, GATA3+ Tregs and Th1 cells in the AR group were significantly reduced, while the proportions of PU-1+ Tregs, T-bet+ Tregs and Th2 cells were significantly increased (P < 0.05). Compared with the AR group, the proportions of Tregs and Th1 cells in the AIT group were significantly increased, while the proportions of PU-1+ Tregs and Th2 cells were decreased (P < 0.05). 3. Correlation analysis showed that Treg cell proportions were negatively correlated with the TNSS, sIgE levels, IL-5 levels and IL-6 levels but positively correlated with the IL-2 and IL-10 levels (P < 0.05). PU-1+ Treg cell proportions were positively correlated with the TNSS, sIgE levels, IL-5 levels and IL-6 levels but negatively correlated with the Treg cell proportions, IL-2 levels and IL-10 levels (P < 0.05).

CONCLUSIONS

AIT can reduce the proportions of PU-1+ Treg subtypes in AR patients. PU-1+ Treg cell numbers can potentially be used as an indicator to monitor the therapeutic effect of AIT on AR.

Autoimmunity and Cancer-Two Sides of the Same Coin

Autoimmune disease results from the immune response against self-antigens, while cancer develops when the immune system does not respond to malignant cells. Thus, for years, autoimmunity and cancer have been considered as two separate fields of research that do not have a lot in common. However, the discovery of immune checkpoints and the development of anti-cancer drugs targeting PD-1 (programmed cell death receptor 1) and CTLA-4 (cytotoxic T lymphocyte antigen 4) pathways proved that studying autoimmune diseases can be extremely helpful in the development of novel anti-cancer drugs. Therefore, autoimmunity and cancer seem to be just two sides of the same coin. In the current review, we broadly discuss how various regulatory cell populations, effector molecules, genetic predisposition, and environmental factors contribute to the loss of self-tolerance in autoimmunity or tolerance induction to cancer. With the current paper, we also aim to convince the readers that the pathways involved in cancer and autoimmune disease development consist of similar molecular players working in opposite directions. Therefore, a deep understanding of the two sides of immune tolerance is crucial for the proper designing of novel and selective immunotherapies.

CD103 integrin identifies a high IL-10-producing FoxP3+ regulatory T-cell population suppressing allergic airway inflammation

BACKGROUND

Although FoxP3⁺ regulatory T (Treg) cells constitute a highly heterogeneous population, with different regulatory potential depending on the disease context, distinct subsets or phenotypes remain poorly defined. This hampers the development of immunotherapy for allergic and autoimmune disorders. The present study aimed at characterizing distinct FoxP3⁺ Treg subpopulations involved in the suppression of Th2-mediated allergic inflammation in the lung.

METHODS

We used an established mouse model of allergic airway disease based on ovalbumin sensitization and challenge to analyze FoxP3⁺ Tregs during the induction and resolution of inflammation, and identify markers that distinguish their most suppressive phenotypes. We also developed a new knock-in mouse model (Foxp3^cre Cd103^dtr ) enabling the specific ablation of CD103⁺ FoxP3⁺ Tregs for functional studies.

RESULTS

We found that during resolution of allergic airway inflammation in mice >50% of FoxP3⁺ Treg cells expressed the integrin CD103 which marks FoxP3⁺ Treg cells of high IL-10 production, increased expression of immunoregulatory molecules such as KLRG1, ICOS and CD127, and enhanced suppressive capacity for Th2-mediated inflammatory responses. CD103⁺ FoxP3⁺ Tregs were essential for keeping allergic inflammation under control as their specific depletion in Foxp3^cre Cd103^dtr mice lead to severe alveocapillary damage, eosinophilic pneumonia, and markedly reduced lifespan of the animals. Conversely, adoptive transfer of CD103⁺ FoxP3⁺ Tregs effectively treated disease, attenuating Th2 responses and allergic inflammation in an IL-10-dependent manner.

CONCLUSIONS

Our study identifies a novel regulatory T-cell population, defined by CD103 expression, programmed to prevent exuberant type 2 inflammation and keep homeostasis in the respiratory tract under control. This has important therapeutic implications.

Th1-Like Treg Cells Are Increased But Deficient in Function in Rheumatoid Arthritis

OBJECTIVES

This study aimed to investigate the changes in quantity and function of T helper (Th)-like T regulatory (Treg) cell subsets in peripheral blood (PB) and synovial fluid (SF) of rheumatoid arthritis (RA) patients and to understand their relationship with disease activity.

METHODS

A total of 86 RA patients and 76 gender and age-matched healthy controls (HC) were enrolled in this study. Th-like Treg frequency and function were determined using flow cytometry. The inhibitory function of Th-like Treg cells was detected using an in vitro co-culture suppression assay.

RESULTS

The proportion and absolute number of Th1-like Treg cells from RA PB and RA SF were significantly higher than those of HC PB. In RA SF, the proportions of Treg cells and Th1-like Treg cells were significantly lower in the elevated erythrocyte sedimentation rate or the C-Reactive Protein group, and in the positive groups of anti-CCP antibody and anti-MCV antibody. Additionally, the proportions of Treg cells and Th1-like Treg cells from RA SF were negatively correlated with disease activity. However, the expression levels of CD73 and TGF-β1 in Th1-like Treg cells were decreased, and these Treg cells could not effectively inhibit the proliferation of effector T (Teff) cells.

CONCLUSION

Our data indicate that Th1-like Treg cells are the predominant Treg cell subset in RA SF, but their suppressive function is defective. Improving the function of Th1-like Treg cells may control inflammation in joints and provide new strategies for Treg-targeted therapies in RA.

Splicing factor SRSF1 controls distinct molecular programs in regulatory and effector T cells implicated in systemic autoimmune disease

Systemic autoimmune diseases are characterized by hyperactive effector T cells (Teffs), aberrant cytokines and chemokines, and dysfunctional regulatory T cells (Tregs). We previously uncovered new roles for serine/arginine-rich splicing factor 1 (SRSF1) in the control of genes involved in T cell signaling and cytokine production in human T cells. SRSF1 levels are decreased in T cells from patients with systemic lupus erythematosus (SLE), and low levels correlate with severe disease. Moreover, T cell-conditional Srsf1-deficient mice recapitulate the autoimmune phenotype, exhibiting CD4 T cell hyperactivity, dysfunctional Tregs, systemic autoimmunity, and tissue inflammation. However, the role of SRSF1 in controlling molecular programs in Teffs and Tregs and how these pathways are implicated in autoimmunity is not known. Here, by comparative bioinformatics analysis, we demonstrate that SRSF1 controls largely distinct gene programs in Tregs and Teffs in vivo. SRSF1 regulates 189 differentially expressed genes (DEGs) unique to Tregs, 582 DEGs unique to Teffs, and 29 DEGs shared between both. Shared genes included IL-17A, IL-17F, CSF1, CXCL10, and CXCR4, and were highly enriched for inflammatory response and cytokine-cytokine receptor interaction pathways. SRSF1 controls distinct pathways in Tregs, which include chemokine signaling and immune cell differentiation, compared with pathways in Teffs, which include cytokine production, T cell homeostasis, and activation. We identified putative mRNA binding targets of SRSF1 which include CSF1, CXCL10, and IL-17F. Finally, comparisons with transcriptomics profiles from lupus-prone MRL/lpr mice reveal that SRSF1 controls genes and pathways implicated in autoimmune disease. The target genes of SRSF1 and putative binding targets we discovered, have known roles in systemic autoimmunity. Our findings suggest that SRSF1 controls distinct molecular pathways in Tregs and Teffs and aberrant SRSF1 levels may contribute to their dysfunction and immunopathogenesis of systemic autoimmune disease.

Oxidative Stress Promotes Instability of Regulatory T Cells in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

We investigated the characteristics of regulatory T cells (Tregs), focusing on the relationship between their stability and reactive oxygen species (ROS), in antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Intracellular expressions of effector cytokines, forkhead box protein 3 (FoxP3), ROS, phosphorylated mammalian target of rapamycin (mTOR), and sirtuin 1 (SIRT1) in Tregs from peripheral blood mononuclear cells (PBMCs) of patients with AAV and healthy controls (HC) were analyzed. The alterations in and functional ability of Tregs were compared before and after resveratrol (RVL) treatment of PBMCs in patients with AAV. Significantly higher expressions of interferon (IFN)-γ, interleukin (IL)-17, IL-4, ROS, and phosphorylated mTOR (pho-mTOR) and lower expression of SIRT1 in CD4+CD25+FoxP3+ cells were found in patients with AAV than in the HC. FoxP3 expression in CD4+CD25+ cells and suppressive function of Tregs were significantly lower in patients with AAV than in the HC. Tregs after RVL treatment demonstrated significant decreases in IFN-γ, ROS, and pho-mTOR levels and increases in FoxP3, SIRT1 levels, and functional activity. Conversely, the direct activation of SIRT1 by SRT1720 resulted in decreased FoxP3 expression, with no reduction in ROS levels. The pho-mTOR levels were significantly higher in Tregs after activation by SRT1720 than in those after RVL treatment. This study suggested that imbalanced changes in Tregs could be attributed to mTOR activation, in which ROS overproduction was predominantly implicated. Therefore, ROS is a key mediator for promoting Tregs instability in AAV.

Butyric Acid Protects Against Renal Ischemia-Reperfusion Injury by Adjusting the Treg/Th17 Balance via HO-1/p-STAT3 Signaling

Immune regulation plays a vital role in ischemia-reperfusion injury (IRI). Butyric acid (BA) has immunomodulatory effects in many diseases, but its immunomodulatory effects during renal IRI are still unclear. Our research shows that BA protected against IRI and significantly improved renal IRI in vivo. In vitro studies showed that BA inhibits Th17 cell differentiation and induces Treg cell differentiation. Mechanism studies have shown that heme oxygenase 1 (HO-1)/STAT3 signaling pathway was involved in the inhibitory effect of BA on Th17 cell differentiation. HO-1 inhibitors can significantly rescue the BA-mediated inhibition of Th17 cell differentiation. We confirmed that BA promotes the differentiation of Th17 cells into Treg cells by regulating the pathway and reduces renal IRI.