Treg Cell Differentiation Research Articles

MiR-223-3p Inhibits Antigen Endocytosis and Presentation and Promotes the Tolerogenic Potential of Dendritic Cells through Targeting Mannose Receptor Signaling and Rhob.

Background The role of miR-223-3p in dendritic cells (DCs) is unknown. This study is aimed at investigating the effect of miR-223-3p on the antigen uptake and presentation capacities of DCs and the underlying molecular mechanism. Methods FITC-OVA antigen uptake and cell surface markers in bone marrow-derived DCs (BMDCs) were analyzed by flow cytometry. BMDCs were transfected with the miR-223-3p mimic or inhibitor. Cytokine levels were determined by ELISA. CD4+ T cell differentiation was determined by mixed lymphocyte culture assay. Results OVA treatment significantly downregulated miR-223-3p in BMDCs. The miR-223-3p mimic significantly inhibited OVA-induced antigen uptake and surface expression of MHC-II on BMDCs (P < 0.01). The miR-223-3p mimic increased TGF-β1 production in OVA-treated DCs (P < 0.01). Mixed lymphocyte reaction showed that the miR-223-3p mimic significantly promoted Treg cell differentiation. In addition, the miR-223-3p mimic significantly upregulated CD103 in DCs, indicating the promotion of tolerogenic DCs. The miR-223-3p mimic downregulated Rhob protein in OVA-induced DCs. Rhob knockdown significantly suppressed the ability of FITC-OVA endocytosis (P < 0.01) and surface MHC-II molecule expression (P < 0.01) in BMDCs, promoting promoted Treg cell differentiation. Mannose receptor (MR) knockdown significantly upregulated miR-223-3p, downregulated Rhob protein in OVA-treated DCs, inhibited the FITC-OVA endocytosis and surface MHC-II expression in BMDCs, and promoted Treg cell differentiation (all P < 0.01). Conclusion These data suggest that miR-223-3p has an inhibitory effect on the antigen uptake and presentation capacities of BMDCs and promotes Treg cell differentiation, which is, at least partially, through targeting MR signaling and Rhob.

065 CDK7 inhibitor suppresses psoriasis inflammation via inhibiting glycolysis to modulate Th17/Treg balance

Psoriasis is a chronic inflammatory disease characterized by hyper-activated Th17 and suppressive Treg cells, but the mechanism of Th17/Treg cells imbalance is still unclear. Cyclin-dependent kinase 7(CDK7) which is known as a cell cycle regulator has been reported an anti-inflammatory effect in immuno-cells. Here we firstly found CD4+T cells of psoriasis patients expressed higher levels of CDK7 along with an increased glycolysis levels than those in healthy controls. The chemical inhibitor of CDK7 called THZ1 restricted glycolytic metabolism in CD4+T cells of psoriasis patients as well as typical glycolysis related genes. More importantly, THZ1 could suppress Th17 cell differentiation and promote Treg cell differentiation even under Th17 polarizing condition in vitro. Intraperitoneal injection of THZ1 in mice exhibited an alleviated epidermal hyperplasia and alleviated inflammation caused by imiquimod(IMQ) treatment. THZ1-treated IMQ mice had significantly lower ratio of Th17 cells and higher ratio of Treg cells from the splenocytes, in comparison with vehicle-treated IMQ mice. Furthermore, we identified IL-23 as an upstream regulator that stimulated CDK7 expression and glycolysis through p-AKT-Hif-1α signalling pathway. Taken together, our results showed that abnormal CDK7 expression induced by IL-23 in CD4+ T cells in psoriasis patients contributed to the enhanced glycolysis levels which lead to the imbalance of Th17/Treg cells. CDK7 inhibitor THZ1 may serve as an immuno-modulator for psoriasis therapy in the future.

Protein Kinase C Theta Modulates PCMT1 through hnRNPL to Regulate FOXP3 Stability in Regulatory T Cells

T cell receptor signaling, together with cytokine-induced signals, can differentially regulate RNA processing to influence T helper versus regulatory Tcell fate. Protein kinase C family members have been shown to function in alternative splicing and RNA processing in various cell types. Tcell-specific protein kinase C theta, a molecular regulator of Tcell receptor downstream signaling, has been shown to phosphorylate splicing factors and affect post-transcriptional control of Tcell gene expression. In this study, we explored how using a synthetic cell-penetrating peptide mimic for intracellular anti-protein kinase C theta delivery fine-tunes differentiation of induced regulatory Tcells through its differential effects on RNA processing. We identified protein kinase C theta signaling as a critical modulator of two key RNA regulatory factors, heterogeneous nuclear ribonucleoprotein L (hnRNPL) and protein-l-isoaspartate O-methyltransferase-1 (PCMT1), and loss of protein kinase C theta function initiated a "switch" in post-transcriptional organization in induced regulatory Tcells. More interestingly, we discovered that protein-l-isoaspartate O- methyltransferase-1 acts as an instability factor in induced regulatory Tcells, by methylating the forkhead box P3 (FOXP3) promoter. Targeting protein-l-isoaspartate O-methyltransferase-1 using a cell-penetrating antibody revealed an efficient means of modulating RNA processing to confer a stable regulatory Tcell phenotype.

Curcumin Promotes the Expression of IL-35 by Regulating Regulatory T Cell Differentiation and Restrains Uncontrolled Inflammation and Lung Injury in Mice.

Interleukin (IL)-35, which has an anti-inflammatory role in acute respiratory distress syndrome (ARDS)/acute lung injury (ALI), is relatively promising as a drug target. Studies have shown that curcumin may play a therapeutic role in ALI and enhance the suppressive function of regulatory T cells (Tregs). To illustrate the effect of curcumin on the regulation of Treg cell differentiation and expression of IL-35, we built a cecal ligation and puncture (CLP)-induced acute lung injury mouse mode with curcumin pretreatment. The expression of IL-35 in serum, severity of lung injury, IL-17A in lung tissue, survival rate, Treg-related cytokines levels in serum, nuclear factor-kappa B (NF-κB)'s nuclear translocation in lung tissue, and splenic CD4+CD25+FOXP3+ Tregs were assessed. Furthermore, the proportion of Tregs, STAT5, and IL-35 expression during naïve CD4+ T cell differentiation in vitro was measured. Compared with the CLP group, the increased IL-35 expression in CLP with the curcumin pretreatment (CLP + Cur) group was consistent with the decreased severity of lung injury, IL-17A protein levels in lung tissue, and Treg-related cytokines levels. Pretreatment with curcumin, the survival rate climbed to 50%, while the mortality rate was 100% in the CLP group. In addition, splenic CD4+CD25+FOXP3+ Treg cells increased in the CLP + Cur group. In vitro, CD4+CD25+FOXP3+ Treg cells from naïve CD4+ T cells, STAT5 proportion, and IL-35 expression increased after curcumin treatment. These findings showed that curcumin might regulate IL-35 by activating the differentiation of Treg cells to control the inflammation in acute lung injury.

Trophoblast H2S Maintains Early Pregnancy via Regulating Maternal-Fetal Interface Immune Hemostasis.

Dysregulated immune hemostasis occurs in unexplained recurrent spontaneous abortion (URSA). Synthesized by cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), hydrogen sulfide (H2S) promotes regulatory T-cell differentiation and regulates immune hemostasis; yet, its role in URSA is elusive. To determine if H2S plays a role in early pregnancy and if dysregulated H2S signaling results in recurrent spontaneous abortion. First trimester placenta villi and decidua were collected from normal and URSA pregnancies. Protein expression was examined by immunohistochemistry and immunoblotting. Human trophoblast HTR8/SVneo and JEG3 cells were treated with H2S donors; HTR8/SVneo cells were transfected with CBS ribonucleic acid interference (RNAi) or complementary deoxyribonucleic acid. Cell migration and invasion were determined by transwell assays; trophoblast transcriptomes were determined by RNA sequencing (RNA-seq). Wild-type, CBS-deficient, and CBA/J × DBA/2 mice were treated with CBS and CSE inhibitors or H2S donors to determine the role of H2S in early pregnancy in vivo. CBS and CSE proteins showed cell-specific expressions, but only CBS decreased in the villous cytotrophoblast in URSA versus normal participants. H2S donors promoted migration and invasion and MMP-2 and VEGF expression in human placenta trophoblast cells that contain SV40 viral deoxyribonucleic acid sequences (HTR8/SVneo) and human placenta trophoblast cells (JEG3 cells), similar to forced CBS expression in HTR8/SVneo cells. The CBS-responsive transcriptomes in HTR8/SVneo cells contained differentially regulated genes (ie, interleukin-1 receptor and prostaglandin-endoperoxide synthase 2) that are associated with nuclear factor-κB-mediated inflammatory response. In vivo, dysregulated CBS/H2S signaling significantly increased embryonic resorption and decidual T-helper 1/T-helper 2 imbalance in mice, which was partially rescued by H2S donors. CBS/H2S signaling maintains early pregnancy, possibly via regulating maternal-fetal interface immune hemostasis, offering opportunities for H2S-based immunotherapies for URSA.

T cells expressing the lupus susceptibility allele Pbx1d enhance autoimmunity and atherosclerosis in dyslipidemic mice.

Patients with systemic lupus erythematosus (SLE) present a high incidence of atherosclerosis, which contributes significantly to morbidity and mortality in this autoimmune disease. An impaired balance between regulatory (Treg) and follicular helper (Tfh) CD4+ T cells is shared by both diseases. However, whether there are common mechanisms of CD4+ T cell dysregulation between SLE and atherosclerosis remains unclear. Pre-B cell leukemia transcription factor 1 isoform d (Pbx1d) is a lupus susceptibility gene that regulates Tfh cell expansion and Treg cell homeostasis. Here, we investigated the role of T cells overexpressing Pbx1d in low-density lipoprotein receptor-deficient (Ldlr-/-) mice fed with a high-fat diet, an experimental model for atherosclerosis. Pbx1d-transgenic T cells exacerbated some phenotypes of atherosclerosis, which were associated with higher autoantibody production, increased Tfh cell frequency, and impaired Treg cell regulation, in Ldlr-/- mice as compared with control T cells. In addition, we showed that dyslipidemia and Pbx1d-transgenic expression independently impaired the differentiation and function of Treg cells in vitro, suggesting a gene/environment additive effect. Thus, our results suggest that the combination of Pbx1d expression in T cells and dyslipidemia exacerbates both atherosclerosis and autoimmunity, at least in part through a dysregulation of Treg cell homeostasis.

THU0085 RESOLVIN D5 MODULATES TH17/TREG CELL DIFFERENTIATION AND SUPPRESSES OSTEOCLASTOGENESIS

Background:Resolution phase of acute inflammation has been recognized not passive but active process during the last 2 decades. This active process is highly regulated by novel families of potent bioactive lipid mediators, which are coined as specialized proresolving mediators (SPMs) including resolvins. Little has been known, however, about how resolvins are involved in chronic inflammation, such as rheumatoid arthritis (RA).Objectives:To investigate whether lipid mediators (LM) are involved in the pathogenesis of RA.Methods:We investigated lipid mediator profiling in the paws of SKG arthritis mice by using lipid chromatography (LC) /mass spectrometry (MS) /MS-based LM metabololipidomics. CD4+T cells from spleens of SKG mice were cultured on anti-CD3/ CD28Abs precoated plate with IL-6/TGF-β, anti-IFNγ/IL-4 and analyzed by flow cytometry. CD4+T cells were labeled with CFSE, and cell proliferation was analyzed by flow cytometry. Mouse bone marrow cells were cultured with M-CSF and RANKL, and TRAP-positive multinucleated cells were defined as osteoclasts. Osteoclast differentiation markers were analyzed by qRT-PCR. RvD5 or normal saline was administered daily into the peritoneal cavity of arthritic SKG mice.Results:RvE3, RvD1, RvD3, RvD5 and Maresin2 were significantly elevated on the paws of arthritic SKG mice. Among the elevated SPMs, only RvD5 levels on arthritic paws were significantly correlated with arthritis disease activity (Figure 1). We demonstrated that RvD5 suppressed Th17 cell differentiation, and facilitated Treg cell differentiationin vitro. In addition, RvD5 inhibited CD4+T cell proliferation. Furthermore, RvD5 attenuated osteoclast differentiation (Figure 2) and interfered osteoclastogenesis at the molecular level. In thein vivoexperiment, incidence of arthritis tended to be lower in RvD5-treated mice than that in control group, although there was no significant difference.Conclusion:RvD5 is increased in the paws of arthritic mice, and that RvD5 suppresses Th17 cell differentiation and CD4+T cell proliferation, facilitates Treg cell differentiation, and suppresses osteoclastogenesis.

Transforming growth factor β (TGF-β) receptor signaling regulates kinase networks and phosphatidylinositol metabolism during T-cell activation

The cytokine content in tissue microenvironments shapes the functional capacity of a T cell. This capacity depends on the integration of extracellular signaling through multiple receptors, including the T-cell receptor (TCR), co-receptors, and cytokine receptors. Transforming growth factor β (TGF-β) signals through its cognate receptor, TGFβR, to SMAD family member proteins and contributes to the generation of a transcriptional program that promotes regulatory T-cell differentiation. In addition to transcription, here we identified specific signaling networks that are regulated by TGFβR. Using an array of biochemical approaches, including immunoblotting, kinase assays, immunoprecipitation, and flow cytometry, we found that TGFβR signaling promotes the formation of a SMAD3/4-protein kinase A (PKA) complex that activates C-terminal Src kinase (CSK) and thereby down-regulates kinases involved in proximal TCR activation. Additionally, TGFβR signaling potentiated CSK phosphorylation of the P85 subunit in the P85-P110 phosphoinositide 3-kinase (PI3K) heterodimer, which reduced PI3K activity and down-regulated the activation of proteins that require phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P3) for their activation. Moreover, TGFβR-mediated disruption of the P85-P110 interaction enabled P85 binding to a lipid phosphatase, phosphatase and tensin homolog (PTEN), aiding in the maintenance of PTEN abundance and thereby promoting elevated PtdIns(4,5)P2 levels in response to TGFβR signaling. Taken together, these results highlight that TGF-β influences the trajectory of early T-cell activation by altering PI3K activity and PtdIns levels.

RNA binding protein PCBP1 is an intracellular immune checkpoint for shaping T cell responses in cancer immunity.

Distinct lineages of T cells can act in response to various environmental cues to either drive or restrict immune-mediated pathology. Here, we identify the RNA binding protein, poly(C)-binding protein 1 (PCBP1) as an intracellular immune checkpoint that is up-regulated in activated T cells to prevent conversion of effector T (Teff) cells into regulatory T (Treg) cells, by restricting the expression of Teff cell-intrinsic Treg commitment programs. This was critical for stabilizing Teff cell functions and subverting immune-suppressive signals. T cell-specific deletion of Pcbp1 favored Treg cell differentiation, enlisted multiple inhibitory immune checkpoint molecules including PD-1, TIGIT, and VISTA on tumor-infiltrating lymphocytes, and blunted antitumor immunity. Our results demonstrate a critical role for PCBP1 as an intracellular immune checkpoint for maintaining Teff cell functions in cancer immunity.

Cell-Penetrating Anti-Protein Kinase C Theta Antibodies Act Intracellularly to Generate Stable, Highly Suppressive Regulatory T Cells

Regulatory Tcells maintain immunological tolerance and dampen inflammatory responses. Administering regulatory Tcells can prevent the immune-mediated tissue destruction of graft-versus-host disease, which frequently accompanies hematopoietic stem cell transfer. Neutralizing the Tcell-specific kinase, protein kinase C theta, which promotes Tcell effector functions and represses regulatory Tcell differentiation, augments regulatory Tcell immunosuppression and stability. We used a synthetic, cell-penetrating peptide mimic to deliver antibodies recognizing protein kinase C theta into primary human CD4 Tcells. When differentiated exvivo into induced regulatory Tcells, treated cells expressed elevated levels of the regulatory Tcell transcriptional regulator forkhead box P3, the surface-bound immune checkpoint receptor programmed death receptor-1, and pro-inflammatory interferon gamma, previously ascribed to a specific population of stable, highly suppressive human induced regulatory Tcells. The invitro suppressive capacity of these induced regulatory Tcells was 10-fold greater than that of Tcells differentiated without antibody delivery. When administered at the time of graft-versus-host disease induction, using a humanized mouse model, antibody-treated regulatory Tcells were superior to non-treated Tcells in attenuating lethal outcomes. This antibody delivery approach may overcome obstacles currently encountered using patient-derived regulatory Tcells as a cell-based therapy for immune modulation.

Regulating T-cell differentiation through the polyamine spermidine

The cross-talk between the host and its microbiota plays a key role in the promotion of health. The production of metabolites such as polyamines by intestinal-resident bacteria is part of this symbiosis shaping host immunity. The polyamines putrescine, spermine, and spermidine are abundant within the gastrointestinal tract and might substantially contribute to gut immunity. We aimed to characterize the polyamine spermidine as a modulator of T-cell differentiation and function. Naive T cells were isolated from wild-type mice or cord blood from healthy donors and submitted to polarizing cytokines, with and without spermidine treatment, to evaluate CD4+ T-cell differentiation invitro. Moreover, mice were subjected to oral supplementation of spermidine, or its precursor l-arginine, to assess the frequency and total numbers of regulatory T (Treg) cells invivo. Spermidine modulates CD4+ T-cell differentiation invitro, preferentially committing naive T cells to a regulatory phenotype. After spermidine treatment, activated T cells lacking the autophagy gene Atg5 fail to upregulate Foxp3 to the same extent as wild-type cells. These results indicate that spermidine's polarizing effect requires an intact autophagic machinery. Furthermore, dietary supplementation with spermidine promotes homeostatic differentiation of Treg cells within the gut and reduces pathology in a model of T-cell transfer-induced colitis. Altogether, our results highlight the beneficial effects of spermidine, or l-arginine, on gut immunity by promoting Treg cell development.

Targeting of Phospholipase D1 Ameliorates Collagen-Induced Arthritis via Modulation of Treg and Th17 Cell Imbalance and Suppression of Osteoclastogenesis.

Phospholipase D1 (PLD1) plays a crucial role in various inflammatory and autoimmune diseases. Rheumatoid arthritis (RA) is a chronic and systemic autoimmune disease. However, the role of PLD1 in the pathogenesis of RA remains unknown. Here, we first investigated the role and effects of PLD1 in collagen-induced arthritis (CIA) and found that genetic and pharmacological inhibition of PLD1 in DBA1/J mice with CIA reduced the incidence of CIA, decreased the clinical score, and abrogated disease symptoms including infiltration of leukocytes, synovial inflammation, bone erosion, and cartilage destruction. Moreover, ablation and inhibition of PLD1 suppressed the production of type II collagen-specific IgG2a autoantibody and proinflammatory cytokines, accompanied by an increase in the regulatory T (Treg) cell population and a decrease in the Th17 cell population in CIA mice. The PLD1 inhibitor also promoted differentiation of Treg cells and suppressed differentiation of Th17 cells in vitro. Furthermore, the PLD1 inhibitor attenuated pathologic bone destruction in CIA mice by suppressing osteoclastogenesis and bone resorption. Thus, our findings indicate that the targeting of PLD1 can ameliorate CIA by modulating the imbalance of Treg and Th17 cells and suppressing osteoclastogenesis, which might be a novel strategy to treat autoimmune diseases, such as RA.

Chloroquine modulates inflammatory autoimmune responses through Nurr1 in autoimmune diseases

Abstract For over a half-century the anti-malarial drug chloroquine (CQ) has been used as a therapeutic agent, alone or in combination, to treat autoimmune diseases. However, neither the underlying mechanism(s) of action nor their molecular target(s) are well defined. The orphan nuclear receptor Nurr1 (also known as NR4A2) is an essential transcription factor affecting the development and maintenance of midbrain dopaminergic neurons. In this study, using in vitro T cell differentiation models, we demonstrate that CQ activates TREG cell differentiation and induces Foxp3 gene expression in a Nurr1-dependent manner. Remarkably, CQ appears to induce Nurr1 function by two distinct mechanisms: firstly, by direct binding to Nurr1’s ligand-binding domain and promoting its transcriptional activity and secondly by upregulation of Nurr1 expression through the CREB signaling pathway. In contrast, CQ suppressed gene expression and differentiation of pathogenic TH17 cells. Importantly, using a valid animal model of inflammatory bowel disease (IBD), we demonstrated that CQ promotes Foxp3 expression and differentiation of TREG cells in a Nurr1-dependent manner, leading to significant improvement of IBD-related symptoms. Taken together, these data suggest that CQ ameliorates autoimmune diseases via regulating Nurr1 function/expression and that Nurr1 is a promising target for developing effective therapeutics of human inflammatory autoimmune diseases.

Anergy-derived Foxp3+ T regulatory cell differentiation in the neonatal mouse

Abstract The neonatal period is a natural scenario to study the effects of peripheral self-antigen (Ag) recognition by autoreactive conventional CD4+ T cells under conditions of low Foxp3+ T regulatory cell (Treg) numbers and function. Moreover, the neonatal environment is an interesting scenario to study the relationship between the induction of CD4+ T cell anergy and the peripheral generation of anergy-derived Tregs, given that anergy induction relies on normal Treg function whereas anergy-derived Treg generation is optimal in the setting of Treg cell deficiency. We have hypothesized that the neonatal period is both necessary and sufficient to allow for the induction of anergy as well as the peripheral differentiation of anergy-derived Foxp3+ Tregs from naive conventional CD4+ T cells during self-Ag recognition. To test our hypotheses we developed a system of neonatal peripheral tolerance induction. Neonatal pups engineered to express the experimental “self” peptide Ag chicken ovalbumin (OVAp) were given OVAp/I-Ab–specific OT-II CD4+ T cells, and the pups were later examined for anergy induction, Treg differentiation, and development of autoimmunity. Our data demonstrate that in the neonatal period: 1) previously naive CD4+ T cells express markers of anergy following exposure to self-Ag, and a small fraction of these cells can be seen to differentiate to a Foxp3+ Treg phenotype, and 2) previously anergic CD4+ T cells typically retain their anergic phenotype but also give rise to a substantial fraction of Foxp3+ Tregs, and 3) animals remain free of autoimmune disease. These findings suggest that during the neonatal period peripheral Foxp3+ Treg cell differentiation may proceed through a conventional anergic CD4+ T cell intermediate.

Bile acid metabolites control Th17 and Treg cell differentiation

Abstract Bile acids are abundantly present in the mammalian gut, where they undergo bacteria-mediated transformation, generating a large pool of bioactive molecules. While they have been shown to affect host metabolism, cancer progression and innate immunity, it is unknown whether bile acids affect the function of adaptive immune cells such as T cells expressing IL-17a (Th17 cells) and regulatory T cells (Tregs) that mediate inflammatory and anti-inflammatory responses, respectively. By screening a small-molecule library primarily composed of bile acid metabolites, we identified two distinct derivatives of lithocholic acid (LCA), 3-oxoLCA and isoalloLCA, as specific regulators of Th17 and Treg cells. While 3-oxoLCA inhibited Th17 cell differentiation by directly binding to its key transcription factor RORγt (retinoid-related orphan receptor γt), isoalloLCA enhanced Treg differentiation through the production of mitochondrial reactive oxygen species (mitoROS), leading to increased FoxP3 expression. IsoalloLCA-mediated Treg enhancement required an intronic FoxP3 enhancer the conserved noncoding sequence 3 (CNS3), suggesting a distinct mode of action from other previously identified Treg enhancing metabolites that require CNS1. Lastly, oral administration of 3-oxoLCA and isoalloLCA to mice led to reduced Th17 and increased Treg cell differentiation in the intestinal lamina propria. Altogether, our data suggest novel mechanisms by which bile acid metabolites control host immune responses by directly modulating the Th17 and Treg balance.

Lupus susceptibility gene Pbx1 promotes atherosclerosis via dysfunctional T cells in a mouse model

Abstract The incidence of atherosclerosis is higher among patients with systemic lupus erythematosus (SLE). An imbalance between regulatory T cells (Treg) and follicular helper T cells (Tfh) occurs in the development and progression in both diseases. However, the mechanisms by which lupus T cells may aggravate atherosclerosis remain unclear. Pre-B-cell leukemia transcription factor 1 isoform d (Pbx1-d) is a lupus susceptibility gene and transgenic (Tg) Pbx1-d in CD4+ T cells expands Tfh and impairs Treg. Here, we investigated the role of CD4-Pbx1-d-Tg T cells in the low-density lipoprotein receptor-deficient (Ldlr−/−) mice, an experimental model for atherosclerosis. Pbx1-d T cells exacerbated atherosclerosis in Ldlr−/− mice as compared to B6 T cells. The enhanced atherosclerosis was associated with increased body weight, increased autoantibody production, reduced Treg in the aorta, as well as increased splenic Tfh frequency and impaired Treg cell suppressive markers. Dyslipidemia inhibited the differentiation and function of Treg cells in vitro. Moreover, Pbx1-d Treg cells were less suppressive than B6 control Treg cells in dyslipidemia conditions. Thus, our results showed that Pbx1-d-Tg T cells exacerbate atherosclerosis due to the dysregulated Treg and Tfh cells, briging autoimmunity and cardiovascular pathology.

Thymic epithelial miR-155 promotes regulatory T cell development through safeguarding medullary thymic epithelial cell maturation

Abstract During thymocyte development, medullary thymic epithelial cells (mTECs) provide appropriate instructive cues in the thymic microenvironment for not only negative selection but also the generation of regulatory T (Treg) cells. Here, we identify that miR-155, a microRNA whose expression in Treg cells has previously been shown to be crucial for their development and homeostasis, also contributes to thymic Treg (tTreg) cell differentiation by promoting mTEC maturation. Mechanistically, we show that RANKL stimulation induces expression of miR-155 to safeguard the thymic medulla through targeting multiple known and previously uncharacterized molecules within the TGFβ signaling pathway, which is recognized for its role in restricting the maturation and expansion of mTECs. Our work uncovers a miR-155-TGFβ axis in the thymic medulla to determine mTEC maturity and, consequently, the quantity of tTreg cells and suggests that miR-155 ensures proper tTreg cell development in both cell-intrinsic and -extrinsic manners.

Sub-lethal Dose of Alcohol Modulates Innate Immune-Mediated Regulatory T-Cell Differentiation

Abstract The use of alcohol for consumption and other purposes is widely prevalent in our society. High concentration of alcohol (ethanol) in the household and clinical cleaners is employed for disinfecting. Deleterious effects of alcohol abuse in terms of death and dysfunction of cells, including immune-cells, has been extensively documented. However, moderate consumption of alcoholic beverages has been indicated to be beneficial. In this study, we sought to investigate the effects of sub-lethal doses of alcohol on the interaction of innate and adaptive immunity. We used murine bone marrow-derived macrophages (BMM) as antigen presenting cells and naïve T-cells isolated from spleens of C57BL/6 mice for in vitro T-helper differentiation assays. We found that doses of alcohol at 3% (v/v) or higher induces severe cell death, whereas lower concentrations of alcohol (&amp;lt;2% v/v) modulates the BMM activity for increased differentiation of T-regulatory cells (Tregs), which play a major role in preventing inflammation. Further, alcohol at lower doses also reversed the inhibitory effect of the endotoxin lipopolysaccharide (LPS) on Treg differentiation. Interestingly, BMM treated with alcohol also increased differentiation of TH17 cells. We also investigated the effects of alcohol-treated BMM on immune-modulation of T-helper differentiation in vivo. The data provide insights for immunomodulatory effects of low doses of alcohol and have implications for the regulation of Tregs.

Inducers, Attractors and Modulators of CD4+ Treg Cells in Non-Small-Cell Lung Cancer.

Lung cancer is the leading cause of cancer-associated deaths worldwide, with non-small cell-lung cancer (NSCLC) accounting for approximately 80% of cases. Immune escape has been demonstrated to play a key role in the initiation and progression of NSCLC, although the underlying mechanisms are diverse and their puzzling nature is far from being understood. As a critical participant in immune escape, the CD4+ T cell subset of regulatory T (Treg) cells, with their immunosuppressive functions, has been implicated in the occurrence of many types of cancers. Additionally, therapies based on Treg blockade have benefited a portion of cancer patients, including those with NSCLC. Accumulating literature has noted high Treg infiltration in NSCLC tumor tissues, bone marrow, lymph nodes and/or blood; moreover, the tumor milieu is involved in regulating the proliferation, differentiation, recruitment and suppressive functions of Treg cells. Multifarious mechanisms by which CD4+ Treg cells are generated, attracted and modulated in the NSCLC milieu will be discussed in this review.

Regulating the balance of Th17/Treg cells in gut-lung axis contributed to the therapeutic effect of Houttuynia cordata polysaccharides on H1N1-induced acute lung injury

Our previous study had demonstrated that oral administration of Houttuynia cordata polysaccharides (HCP) without in vitro antiviral activity ameliorated gut and lung injuries induced by influenza A virus (IAV) in mice. However, as macromolecules, HCP was hard to be absorbed in gastrointestinal tract and had no effect on lung injury when administrated intravenously. The action mechanism of HCP was thus proposed as regulating the gut mucosal-associated lymphoid tissue (GALT). Actually, HCP treatment restored the balance of Th17/Treg cells firstly in GALT and finally in the lung. HCP reduced the expression of chemokine CCL20 in the lung and regulated the balance of Th17/Treg carrying CCR6+ (the CCL20 receptor), which was associated with specific migration of Th17/Treg cells from GALT to lung. In vitro, HCP inhibited Th17 cell differentiation through the downregulation of phospho-STAT3, whereas it promoted Treg cell differentiation by upregulating phospho-STAT5. Furthermore, its therapeutic effect was abolished in RORγt−/− or Foxp3−/− mice. These findings indicated that oral administration of macromolecular polysaccharides like HCP might ameliorate lung injury in IAV infected mice via directly regulating the balance of Th17/Treg cells in gut-lung axis. Our results provided a potential mechanism underlying the therapeutic effect of polysaccharides on pulmonary infection.