Treg Expression Research Articles

GPR174 knockdown enhances blood flow recovery in hindlimb ischemia mice model by upregulating AREG expression

Regulatory T cells (Tregs) are critically involved in neovascularization, an important compensatory mechanism in peripheral artery disease. The contribution of G protein coupled receptor 174 (GPR174), which is a regulator of Treg function and development, in neovascularization remains elusive. Here, we show that genetic deletion of GPR174 in Tregs potentiated blood flow recovery in mice after hindlimb ischemia. GPR174 deficiency upregulates amphiregulin (AREG) expression in Tregs, thereby enhancing endothelial cell functions and reducing pro-inflammatory macrophage polarization and endothelial cell apoptosis. Mechanically, GPR174 regulates AREG expression by inhibiting the nuclear accumulation of early growth response protein 1 (EGR1) via Gαs/cAMP/PKA signal pathway activation. Collectively, these findings demonstrate that GPR174 negatively regulates angiogenesis and vascular remodeling in response to ischemic injury and that GPR174 may be a potential molecular target for therapeutic interventions of ischemic vascular diseases.

Dissecting the role of CSF2RB expression in human regulatory T cells.

Colony stimulating factor 2 receptor subunit beta (CSF2RB; CD131) is the common subunit of the type I cytokine receptors for granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-3 and IL-5. Interestingly, FOXP3+ regulatory T cells (Tregs), which play a pivotal role in prevention of autoimmunity have been demonstrated to highly overexpress CSF2RB and genome-wide association studies (GWAS) identified CSF2RB as being linked to autoimmune diseases like multiple sclerosis (MS). However, the exact biological role of CD131 in human Tregs has not been defined yet. Here we investigated CD131 importance on Treg phenotype and function in a broad range of in vitro studies. Although we could not recognize a specific function of CSF2RB; CD131 in human Tregs, our data show that CD131 expression is vastly restricted to Tregs even under stimulatory conditions, indicating that CD131 could aid as a potential marker to identify Treg subpopulations from pools of activated CD4+ T cells. Importantly, our analysis further demonstrate the overexpression of CSF2RB in Tregs of patients with autoimmune diseases like MS and systemic lupus erythematosus (SLE) in comparison to healthy controls, thereby indicating that CSF2RB expression in Tregs could serve as a potential novel biomarker for disease.

Expression of Tregs and IL-35 in Peripheral Blood of Patients with Newly Diagnosed Acute Myeloid Leukemia

To explore the expression of regulatory T cells (Tregs) and interleukin-35 (IL-35) in peripheral blood of patients with newly diagnosed acute myeloid leukemia (AML). Peripheral blood samples were collected from 33 newly diagnosed AML patients and 40 healthy volunteers. The levels of innate and adaptive immune cells and Tregs were detected by flow cytometry. Plasma IL-35 level was detected by enzyme-linked immunosorbent assay (ELISA). The expression levels of P35 and EBI3 mRNA were detected by RT-PCR. The correlation between the levels of Tregs and IL-35 was analyzed. The proportion of CD4+T cells, CD8+T cells, B cells and NK cells in peripheral blood of newly diagnosed AML patients were significantly lower than those of control group (P<0.05). The levels of Tregs, IL-35, and the expression of P35 mRNA and EBI3 mRNA were significantly higher than that of healthy control group (P<0.01). The Tregs level was positively correlated with plasma IL-35 level (r=0.668,P<0.01). AML patients have a deficiency in immune function, which is characterized by the high levels of Tregs and IL-35 in peripheral blood, and it might be a new target for the treatment of AML.

The role of mesenchymal stem cells in allergic rhinitis and its relationship with IL-10, plasma cells and regulatory T cells.

Aim Allergic rhinitis (AR) is an IgE-mediated inflammation of the nose. Regulatory T cells (Tregs), plasma cells and inflammatory cytokines have shown to play a critical role in allergic airway inflammation. The aim of the study was to investigate the role of mesenchymal stem cells (MSCs) in generating Treg cells and plasma cells associated with regulating interlukin-10 (IL-10) in AR model. Methods Fifteen male Wistar rats (6 to 8 weeks old) were randomly divided into three groups (control group, sham group, and MSCs treatment group). Ovalbumin (OVA) nasal challenge was conducted daily from day 15 to 21, and MSCs (1x106) were administrated intraperitoneally to OVA-sensitized rats on day 21. Sneezing was observed from day 24 to 27. The rats were sacrificed on day 24 and day 27. The expression of Treg and plasma cells was analysed by flow cytometry assay. The level of IL-10 was analysed under ELISA assay. Results This study showed that the percentage of sneezing and rubbing times significantly decreased in MSCs treatment associated with the regulation of IL-10 level and plasma cell. This finding was aligned with the significant increase of Treg level. Conclusion MSCs administration regulates IL-10 and plasma cell-mediated immune and inflammatory responses while increasing Treg cell production. MSCs may be a promising therapeutic target for treating Treg-mediated allergic diseases.

CD169+ Monocyte and Regulatory T Cell Subsets Are Associated with Disease Activity in Rheumatoid Arthritis.

Disease activity in rheumatoid arthritis (RA) is influenced by activation of circulating and synovial immune cells. Regulatory T cells (Tregs) and monocytes are key cells that drive inflammation in RA. This study investigated if a relationship exists between disease activity in RA and circulating Treg and monocyte numbers and phenotypes. A potential sialic acid (Sia) mediated link between Tregs and monocytes was also probed in vitro. Peripheral blood mononuclear cells (PBMCs) were isolated from RA patient (n = 62) and healthy control (n = 21) blood using density gradient separation. Flow cytometry was used to count and phenotype Treg and monocyte subsets, and to sort healthy control Tregs for Sia cell culture experiments. The effects of Sia on activated Treg FoxP3 and NFκB expression was assessed by flow cytometry and concentrations of secreted TNFα, IL-10 and IFNγ determined by ELISA. High disease activity RA patients who were unresponsive to disease modifying anti-rheumatic drugs (n = 31), have significantly lower relative numbers (percentages) of CD4+CD25+CD127- Tregs (p &lt; 0.01) and memory CD45RA-FoxP3+ Tregs (p &lt; 0.01), compared to low disease activity responders (n = 24). Relative numbers of non-classical CD169+ monocytes are associated with disease activity in RA (p = 0.012). Sia reduced Treg expression of FoxP3, NFκB and cytokines in vitro. A strong association has been identified between non-classical CD169+ monocytes and post-treatment disease activity in RA. This study also indicates that Sia can reduce Treg activation and cytokine release. We postulate that such a reduction could be mediated by interaction with sialyted proteins captured by CD169+ monocytes.

α-Synuclein induces Th17 differentiation and impairs the function and stability of Tregs by promoting RORC transcription in Parkinson's disease

BackgroundParkinson’s disease (PD) is characterized by the loss of dopaminergic neurons (DA) and the accumulation of Lewy body deposits composed of alpha-Synuclein (α-Syn), which act as antigenic epitopes to drive cytotoxic T-cell responses in PD. Increased T helper 17 (Th17) cells and dysfunctional regulatory T cells (Tregs) have been reported to be associated with the loss of DA in PD. However, the mechanism underlying the Th17/Treg imbalance remains unknown. MethodsHere, we examined the percentage of Th17 cells, the percentage of Tregs and the α-Syn level and analysed their correlations in the peripheral blood of PD patients and in the substantia nigra pars compacta (SNpc) and spleen of MPTP-treated mice and A53 transgenic mice. We assessed the effect of α-Syn on the stability and function of Tregs and the differentiation of Th17 cells and evaluated the role of retinoid-related orphan nuclear receptor (RORγt) upregulation in α-Syn stimulation in vivo and in vitro. ResultsWe found that the α-Syn level and severity of motor symptoms were positively correlated with the increase in Th17 cells and decrease in Tregs in PD patients. Moreover, α-Syn stimulation led to the loss of Forkhead box protein P3 (FOXP3) expression in Tregs, accompanied by the acquisition of IL-17A expression. Increased Th17 differentiation was detected upon α-Syn stimulation when naïve CD4+ T cells were cultured under Th17-polarizing conditions. Mechanistically, α-Syn promotes the transcription of RORC, encoding RORγt, in Tregs and Th17 cells, leading to increased Th17 differentiation and loss of Treg function. Intriguingly, the increase in Th17 cells, decrease in Tregs and apoptosis of DA were suppressed by a RORγt inhibitor (GSK805) in MPTP-treated mice. ConclusionTogether, our data suggest that α-Syn promotes the transcription of RORC in circulating CD4+ T cells, including Tregs and Th17 cells, to impair the stability of Tregs and promote the differentiation of Th17 cells in PD. Inhibition of RORγt attenuated the apoptosis of DA and alleviated the increase in Th17 cells and decrease in Tregs in PD.

MiR-125b-5p modulates the function of regulatory T cells in tumor microenvironment by targeting TNFR2

BackgroundTumor necrosis factor receptor type 2 (TNFR2) is primarily expressed by CD4+FoxP3+ regulatory T cells (Tregs), especially those present in tumor microenvironment. There is compelling evidence that TNFR2 plays a...

FGF15 Protects Septic Mice by Inhibiting Inflammation and Modulating Treg Responses.

Fibroblast growth factor 15 (FGF15) through its FGF-receptor (FGFR)-4 inhibits hepatic inflammation. The current study aimed at investigating whether FGF15 could inhibit septic inflammation and its compensative regulatory T cell (Treg) responses in a mouse sepsis model of cecal ligation and puncture (CLP) and in vitro transwell co-culture. Following the sham or CLP procedure, male CLP C57BL/6 mice were intravenously injected with vehicle saline or FGF15 beginning at 2 h post the procedure every 12 h for three days. Some mice were euthanized and their serum and liver samples were collected for examination of cytokines and Tregs by enzyme-linked immunosorbent assay (ELISA), Western blot and flow cytometry. The remaining mice were monitored for their survival up to 14 days post procedure. Moreover, the purified hepatic CD4+ T cells were co-cultured in transwell plates with unmanipulated NCTC 1469 cells or the cells that had been transfected with the control or FGFR4-specific siRNA and treated with, or without, Lipopolysaccharides (LPS) for 24 h, followed by treatment with vehicle PBS or FGF15 for 48 h. Compared with the CLP group of mice, treatment with FGF15 significantly prolonged the mean survival days of mice (12 vs 1.17 in the CLP group, P = 0.022), mitigated hepatic inflammation and reduced the frequency of apoptotic cells in the liver of mice. FGF15 treatment decreased the percentages of hepatic Tregs, hepatic IL-2, TGF-β and FOXP3 expression in septic mice, accompanied by decreasing serum IL-1β, TNF-α, IL-6 and IL-10 levels. Similarly, FGF15 treatment also attenuated the LPS-increased frequency of Tregs, FOXP3 and IL-2 expression and IL-1β, TNF-α, IL-6 and IL-10 secretion in vitro after co-culture with NCTC 1469 cells, but not co-cultured FGFR4-silenced NCTC 1649 cells. FGF15 treatment through FGFR4 ameliorated hepatic inflammation and its compensative Treg responses, which were associated with protecting from septic death in mice.

The environmental pollutant 3-methyl-4-nitrophenol reduces the regulatory T cells in the intestine

Dysfunction of immune regulation plays a crucial role in the pathogenesis of many immune disorders in the body. The underlying mechanism is still not completely understood. Environmental pollution contributes to immune de-regulation. 3-methyl-4-nitrophenol (MNP) is one of the major environmental pollutants. This study aims to investigate the role of MNP in compromising immune regulatory functions in the intestine. A food allergy (FA) mouse model was established using ovalbumin (OVA) as the specific antigen. The activities of regulatory T cells in the mouse intestine were evaluated by flow cytometry and enzyme-linked immunosorbent assay. We found that MNP reduced the CD4+ Foxp3+ Treg frequency, increased Th17 cells, and converted Tregs to Th17 cells in the intestine. MNP induced the expression of IL-6 in regulatory T cells (Tregs). Estrogen receptor (ER) mediated the effects of MNP on promoting IL-6 expression in Tregs. The IL-6 in synergy with transforming growth factor (TGF)-β to convert Tregs to Th17 cells. The concomitant exposure of MNP and OVA induced FA like response in mice. Modulation of the ER-STAT3-IL-6 signal pathway attenuated mouse FA response. In summary, MNP, an environmental pollutant, acts as an immunoadjuvant for developing FA. By activation of the estrogen receptor, MNP induces Tregs to express IL-6. IL-6 in synergy with TGF-β converts Tregs to Th17 cells.

The Efficacy and Safety of the Zhuyun Formula and Auricular Acupressure for the Infertile Women with Recurrent Implantation Failure: A Randomized Controlled Trial.

Background Recurrent implantation failure (RIF), a clinical disorder characterized by failure to achieve pregnancy after repeated (≥3) embryo transfer, is a challenge for reproductive demands worldwide. In our preliminary work, the Zhuyun formula (ZYF) with auricular acupressure, a complementary and alternative medicine (CAM) with a small sample size for RIF, can improve the clinical pregnancy rate (41.2% vs. 26.7%, treatment group vs. control group, p < 0.05). Based on the toxicological and pregnancy-related pharmacological analysis of ZYF for RIF, the T-cell receptor signaling pathway might be involved in the pharmacological activity. This study aimed at evaluating the efficacy and safety of the CAM therapy according to pregnancy outcomes and maternal and child health and investigating the changes of T-helper (Th) cells in the peripheral blood of unexplained RIF women. Materials and Methods We conducted a prospective, two-arms, randomized, nonblinded study. All eligible women were randomly assigned to the treatment group (TG) and the control group (CG) according to a computer-generated randomization list in sealed opaque envelopes. Blood samples were collected from the two groups, and serum Th1, Th2, and Treg were detected by flow cytometry. The cytokines were detected by an enzyme-linked immunosorbent assay (ELISA). The TG was administrated with ZYF and auricular acupressure for three months before ovarian stimulation, while the control group was on a waiting list for the same period. The primary outcome was CPR. The second outcomes were the serum levels of immune parameters. For the safety evaluation, the perinatal outcomes of maternal and child were obtained by follow-up. Post-hoc sensitivity analyses were performed to assess the effect of missing data. Results One hundred and twenty-three women were randomized into the TG (n = 62) and CG (n = 61). The CPR was increased significantly in the TG (45.2%) than CG (26.2%) (p = 0.029). Twenty blood samples were collected, and the Th2/Th1 and Treg expression level was significantly higher in the TG than in the CG. IL-2, IL-10, and Foxp3 were higher significantly in the TG than in the CG. The maternal and child perinatal outcomes were not significantly different between the two groups. Conclusions The ZYF with auricular acupressure was effective and safe in improving the pregnancy outcomes of RIF. It might be related to balancing the level of cytokines related to the immune tolerance of the maternal-fetal interface to protect the embryo from the maternal immune system. Clinical Trial Registration: Clinical Trial Registry; date: 14/Dec/2013; no. NCT03078205.

Prognostic value of FOXP3+ regulatory T cells in patients with diffuse large B-cell lymphoma: a systematic review and meta-analysis

ObjectivesWe aimed to comprehensively evaluate the relationship between forkhead box P3 (FOXP3+) regulatory T cell (Treg) expression and diffuse large B-cell lymphoma (DLBCL) prognosis and to explore the sources of...

Forced Fox-P3 expression can improve the safety and antigen-specific function of engineered regulatory T cells

Regulatory T cells (Treg) are potent inhibitors of autoreactive T cells. The intracellular transcription factor FoxP3 controls the expression levels of a diverse set of genes and plays a critical role in programming functional Tregs. Although, antigen-specific Tregs are more potent than polyclonal Tregs in treating ongoing autoimmunity, phenotype plasticity associated with loss of FoxP3 expression in Tregs can lead to the conversion into antigen-specific effector T cells which might exacerbate autoimmune pathology. In this study, we designed a retroviral vector driving the expression of FoxP3 and a human HLA-DR-restricted TCR from the same promoter. Transduction of purified human Tregs revealed that all TCR-positive cells had elevated levels of FoxP3 expression, increased CD25 and CTLA4 expression and potent suppressive function. Elevated FoxP3 expression did not impair the in vitro expansion of engineered Tregs. Adoptive transfer into HLA-DR transgenic mice revealed that FoxP3+TCR engineered Tregs showed long-term persistence with stable FoxP3 and TCR expression. In contrast, adoptive transfer of Tregs engineered with TCR only resulted in the accumulation of TCR-positive, FoxP3-negative T cells which displayed antigen-specific effector function when stimulated with the TCR-recognised peptides. Our data indicate that forced expression of FoxP3 can prevent accumulation of antigen-specific effector T cells without impairing the engraftment and persistence of engineered Tregs.

Suppression of FOXP3 expression by the AP-1 family transcription factor BATF3 requires partnering with IRF4.

FOXP3 is the lineage-defining transcription factor for Tregs, a cell type critical to immune tolerance, but the mechanisms that control FOXP3 expression in Tregs remain incompletely defined, particularly as it relates to signals downstream of TCR and CD28 signaling. Herein, we studied the role of IRF4 and BATF3, two transcription factors upregulated upon T cell activation, to the conversion of conventional CD4+ T cells to FOXP3+ T cells (iTregs) in vitro. We found that IRF4 must partner with BATF3 to bind to a regulatory region in the Foxp3 locus where they cooperatively repress FOXP3 expression and iTreg induction. In addition, we found that interactions of these transcription factors are necessary for glycolytic reprogramming of activated T cells that is antagonistic to FOXP3 expression and stability. As a result, Irf4 KO iTregs show increased demethylation of the critical CNS2 region in the Foxp3 locus. Together, our findings provide important insights how BATF3 and IRF4 interactions integrate activating signals to control CD4+ cell fate decisions and govern Foxp3 expression.

Tumour-draining lymph nodes in head and neck cancer are characterized by accumulation of CTLA-4 and PD-1 expressing Treg cells

IntroductionHigh Tregs infiltration within the tumour microenvironment (TME) of various cancers shows a positive correlation with poor prognosis. Despite the fact that tumour draining lymph nodes (TDLNs) are recognized as key organs playing a crucial role in response to immunotherapy and modulating anti-cancer immunity, the distribution of Tregs and their role in TDLNs remain uncertain thus far. The purpose of this project is to investigate the density of Tregs in TDLNs and non-TDLNs and their expression of immune checkpoint molecules – PD-1 and CTLA-4. MethodsSamples including TDLNs, non-TDLNs and metastatic lymph nodes (LNs) from 23 patients with oral squamous cell carcinoma (OSCC) were analyzed by multicolour flow cytometry with a focus on Tregs population and expression of CTLA-4 and PD-1. ResultsTDLNs and metastatic LNs were characterized by a significantly higher infiltration of Tregs defined as CD4+FoxP3+CD25highCD127low cells and significantly higher expression of CTLA-4 and PD-1 on Tregs compared with non-TDLNs. Tregs in TDLNs and metastatic LNs co-expressed CTLA-4 and PD-1 abundantly. High expression of these immune check-point molecules correlated with positive N-stage but not with T-stage. ConclusionTDLNs and metastatic LNs are characterized by a high accumulation of Tregs expressing high levels of CTLA-4 and PD-1. High infiltration of Tregs can be a potential driver of an immunosuppressive milieu in TDLNs that can, in turn, favour cancer progression. High accumulation of Tregs expressing CTLA-4 and PD-1 in TDLNs is associated with lymph node involvement, but not with the size of the primary tumour.

3D Collagen Fiber Concentration Regulates Treg Cell Infiltration in Triple Negative Breast Cancer.

BackgroundTriple negative breast cancer (TNBC) is characterized by poor prognosis and a lack of effective therapeutic agents owing to the absence of biomarkers. A high abundance of tumor-infiltrating regulatory T cells (Tregs) was associated with worse prognosis in malignant disease. Exploring the association between Treg cell infiltration and TNBC will provide new insights for understanding TNBC immunosuppression and may pave the way for developing novel immune-based treatments.Materials and MethodsPatients from TCGA were divided into Treg-high (Treg-H) and Treg-low (Treg-L) groups based on the abundance of Tregs according to CIBERSORT analysis. The association between expression level of Tregs and the clinical characteristics as well as prognosis of breast cancer were evaluated. Next, a Treg-related prognostic model was established after survival-dependent univariate Cox and LASSO regression analysis, companied with an external GEO cohort validation. Then, GO, KEGG and GSEA analyses were performed between the Treg-H and Treg-L groups. Masson and Sirius red/Fast Green staining were applied for ECM characterization. Accordingly, Jurkat T cells were encapsulated in 3D collagen to mimic the ECM microenvironment, and the expression levels of CD4, FOXP3 and CD25 were quantified according to immunofluorescence staining.ResultsThe expression level of Tregs is significantly associated with the clinical characteristics of breast cancer patients, and a high level of Treg cell expression indicates a poor prognosis in TNBC. To further evaluate this, a Treg-related prognostic model was established that accurately predicted outcomes in both TCGA training and GEO validation cohorts of TNBC patients. Subsequently, ECM-associated signaling pathways were identified between the Treg-H and Treg-L groups, indicating the role of ECM in Treg infiltration. Since we found increasing collagen concentrations in TNBC patients with distant migration, we encapsulated Jurkat T cells within a 3D matrix with different collagen concentrations and observed that increasing collagen concentrations promoted the expression of Treg biomarkers, supporting the regulatory role of ECM in Treg infiltration.ConclusionOur results support the association between Treg expression and breast cancer progression as well as prognosis in the TNBC subtype. Moreover, increasing collagen density may promote Treg infiltration, and thus induce an immunosuppressed TME.

Regulatory T cells, damage-associated molecular patterns, and myeloid-derived suppressor cells in bronchoalveolar lavage fluid interlinked with chronic obstructive pulmonary disease severity: An observational study.

The role of regulatory T cells (Tregs), damage-associated molecular patterns (DAMPs), and myeloid-derived suppressor cells (MDSCs) in the mechanism of innate and adaptive immune responses in chronic obstructive pulmonary disease (COPD) is not well understood.Evaluating the presence of Tregs in the bronchoalveolar lavage fluid (BALF) and peripheral blood in patients with COPD, and assessment of the relationship between Tregs, MDSCs, and DAMPs as factors activating innate and adaptive immune responses. Description of the association between immune and clinical parameters in COPD.Thirty-one patients with COPD were enrolled. Clinical parameters (forced expiratory volume in one second [FEV1], forced vital capacity, total lung capacity [TLC], diffusion capacity of carbon monoxide, and B-BMI, O-obstruction, D-dyspnea, E-exercise [BODE]) were assessed. Tregs and MDSCs were investigated in the BALF and blood using monoclonal antibodies directly conjugated with fluorochromes in flow cytometry. The levels of defensin (DEF2), galectin-1 (Gal-1), galectin-3 (Gal-3), galectin-9 (Gal-9), heat shock protein-27 (HSP27), and surfactant protein A were assessed via sandwich enzyme-linked immunosorbent assay.The percentage of Tregs was significantly higher in the blood than in the BALF, in contrast to the mean fluorescence intensity of forkhead box P3 (FoxP3). Significant associations were observed between Tregs and HSP27 (r = 0.39), Gal-1 (r = 0.55), Gal-9 (r = −0.46), and MDSCs (r = −0.50), and between FoxP3 and Gal-1 (r = −0.42), Gal-3 (r = −0.39), and MDSCs (r = −0.43). Tregs and clinical parameters, including FEV1%pred (r = 0.39), residual volume (RV)%pred (r = −0.56), TLC%pred (r = −0.55), RV/TLC (r = −0.50), arterial oxygen saturation (r = −0.38), and arterial oxygen pressure (r = −0.39) were significantly correlated. FoxP3 was significantly interlinked with RV/TLC (r = −0.52), arterial oxygen pressure (r = 0.42), and BODE index (r = −0.57).The interaction between innate and adaptive immune responses in patients with COPD was confirmed. The expression of Tregs in BALF may have prognostic value in patients with COPD. The conversion of immune responses to clinical parameters appears to be associated with disease severity.

Pneumococcal pep27-mutant inhibits Wnt5a expression via the regulation of T helper cells to attenuate colitis

Inflammatory bowel disease (IBD) is a chronic gut inflammatory disease characterized by extensive colitis and remission of the symptoms. The incidence rate and prevalence of IBD are increasing worldwide; IBD affects millions of people, has poorly defined etiology, and often results in a failure of pharmacological interventions. Regardless of the cause, mucosal healing is indispensable for the regeneration of inflamed mucosa to ensure intestinal homeostasis. Intranasal immunization with the pneumococcal pep27 mutant (Δpep27) has been reported as an avirulent and live vaccine that has been proposed to suppress immune-regulated disorders, eliciting long-lasting immunity. The dose-dependent activity of Δpep27 in the lungs was measured by transcriptome analysis to investigate the long-lasting immunogenic response against IBD. Novel therapeutic targets based on the modulation of Wnt signaling and T regulatory cells interconnected with other signaling cascades in the context of IBD were investigated by qPCR and immunoblotting. M1/M2 macrophages were quantified by FACS analysis. Dextran sulfate sodium-induced colitis induced significant upregulation of Th2 and Th17 as well as noncanonical Wnt5, which subsequently inhibited regulatory T (Treg) expression. In contrast, Δpep27 immunization significantly attenuated the levels of Wnt5, proinflammatory cytokines, oxidative stress parameters, and infiltration of inflammatory cells and enhanced barrier integrity via T helper cell homeostasis and upregulation of M2 macrophages. The data of the present study suggested that Δpep27-elicited Tregs were able to repress Wnt5a expression, assisting with the restoration of immunological tolerance and providing a robust regenerative and antioxidant milieu.

Frequency of CD4+ regulatory T cells and modulation of CD4+T lymphocyte activation in pleural tuberculoma

BackgroundThe expression of regulatory T cells (Tregs) is elevated in patients with active tuberculosis (TB) or multidrug-resistant TB. However, it remains uncertain whether Tregs mediate immune suppression in pleural tuberculoma (PTM). MethodsPeripheral venous blood and clinical data were collected from 56 PTM patients and 50 healthy volunteers. The expression of CD38 and HLA-DR expression in T cell subsets and Tregs was determined by flow cytometry. ResultsPTM patients had significantly more Tregs than the matched healthy controls. The expression of CD4+T cells normalized after treatment. Although the median proportions of CD3+T, CD4+T, and CD8+T lymphocytes did not differ significantly between PTM patients and healthy controls, the CD4/CD8 ratio was higher in PTM patients. Moreover, the proportion of CD4+T lymphocytes expressing activation markers, including HLA-DR and CD38, was higher in PTM patients than healthy controls. Treg expression was positively associated with the level of CD4+T lymphocyte activation. ConclusionsThe increased expression of Tregs seen in PTM patients, and subsequent decrease after treatment, indicate that Tregs play an important role in the immune reactivity of PTM.

Treg-specific ablation of HuR results in systemic autoimmunity associated with decreased TLR4 activation and IL-1β production

Abstract The RNA-binding protein HuR (Elavl1) plays a critical role in T cell activation and function by regulating the stability and transport of its mRNA targets. To study the role of HuR in regulatory T cell (Treg) development and function, we generated the Foxp3YFP-Cre HuRfl/fl mouse in which HuR is selectively deleted in CD4+Foxp3+ cells, a lineage with crucial roles in self-tolerance and immune homeostasis. Foxp3+ Treg-specific HuR deletion results in abnormal phenotypic features (scurfy-like mice, hair loss, stippled/banded tails, significant failure to thrive, splenomegaly and multi-organ inflammation, including lung and lymphoid organs), likely the result of reduced Treg function, a phenotype similar to human IPEX syndrome (an autoimmune disorder). Unexpectedly, our RNAseq data showed reduced levels of TLR4, IL-1β, IL-18 and NLRP3 mRNA expression in HuR deficient Tregs (Foxp3YFP-Cre HuRfl/fl). In control WT mice, in vitro LPS treatment of Tregs induced increased expression of TLR4 and IL-1β production, associated with increased nucleocytoplasmic shuttling of HuR. In contrast, the expression of TLR4 and IL-1β was significantly decreased in Tregs from Foxp3YFP-Cre HuRfl/fl mice. Homozygous Foxp3YFP-Cre HuRfl/fl mice had statistically significant reductions in Treg numbers and increased frequency of activated effector T cells. We were also able to detect IL-1β secretion from WT Tregs in vitro following LPS treatment, which was amplified by the addition of DAMP agonists (e.g., ATP or Nigericin). In contrast, HuR KO Tregs had decreases in IL-1β secretion. Together, our data show that HuR is critical for normal CD4+Foxp3+ regulatory T cell function. Supported by grants from NIH (R01 AI080870 and R21 AI079341).

Enhancing and stabilization of cord blood regulatory T-cell suppressive function by human mesenchymal stem cell (MSC)-derived exosomes.

FOXP3+ regulatory T cells (Tregs) are central to maintaining peripheral tolerance and immune homeostasis. They have the potential to be developed as a cellular therapy to treat various clinical ailments such as autoimmune disorders, inflammatory diseases and to improve transplantation outcomes. However, a major question remains whether Tregs can persist and exert their function effectively in a disease state, where a broad spectrum of inflammatory mediators could inactivate Tregs. In this study, we investigated the potential of mesenchymal stem cell (MSC)-derived exosomes to promote and sustain Tregs function. MSC-conditioned media (MSC-CM) cultured Tregs were more suppressive in both polyclonal and allogeneic responses and were resistant to inflammatory stimulation in vitro compared with the controls. A similar enhancement of Treg function was also observed by culturing Tregs with MSC-derived exosomes alone. The enhanced suppressive activity and stability of Treg cultured in MSC-CM was reduced when exosomes were depleted from MSC-CM. We identified that MSC-derived exosomes could upregulate the expression of LC3(II/I), phosphorylate Jak3 and Stat5 to promote Treg survival, and regulate FOXP3 expression in Tregs. Overall, our study demonstrates that MSC-derived exosomes are capable of enhancing Hucb-Tregs function and stability by activating autophagy and Stat5 signalling pathways. Our findings provide a strong rationale for utilizing MSC-derived exosomes as an effective strategy to enhance Treg function, and improve the overall Tregs-based cell therapy landscape.