Induction Of Foxp3 Expression Research Articles

ADENOSINE INFLUENCES FOXP3 EXPRESSION OF T REGS VIA THE A2AR/CREB PATHWAY IN A MOUSE MODEL OF SEPSIS.

The adenosine concentration and forkhead box protein (Foxp3) expression in T regulatory cells (T regs ) are increased during sepsis. However, the mechanism by which adenosine induces Foxp3 expression is incompletely understood. A cecal ligation and puncture (CLP) model was constructed using C57BL/J mice. The plasma adenosine concentration and Foxp3 expression in splenic T regs were increased consistently for 15 days after sepsis onset. Analysis of the mean fluorescence intensity of Foxp3 and adenosine concentration in the same mice revealed a linear correlation. In the CLP model, adenosine 2a receptor (A2aR) blockade inhibited Foxp3 expression in T regs . In vitro activation of A2aR promoted Foxp3 expression in T regs and facilitated secretion of extracellular vesicles. Transcriptome sequencing revealed that A2aR blockade led to changes in cyclic adenosine monophosphate response element-binding protein (CREB) transcription in T regs in our sepsis model. Use of adenosine or A2aR agonists promoted CREB expression, CREB phosphorylation at S133, T reg expression of Foxp3, and enhanced inhibition of proliferation of cluster of differentiation (CD)4+ lymphocytes. A2aR blockade or inhibition of CREB expression inhibited Foxp3 expression in T regs . In the CLP model, use of CREB inhibitors could inhibit Foxp3 expression and reduce the bacterial load. In summary, adenosine in sepsis promotes CREB phosphorylation via A2aR which, in turn, upregulates Foxp3 expression in T regs .

Heat shock factor 1 drives regulatory T-cell induction to limit murine intestinal inflammation

The heat shock response is a critical component of the inflammatory cascade that prevents misfolding of new proteins and regulates immune responses. Activation of CD4+ T cells causes an upregulation of heat shock transcription factor, heat shock factor 1 (HSF1). We hypothesized that HSF1 promotes a pro-regulatory phenotype during inflammation. To validate this hypothesis, we interrogated cell-specific HSF1 knockout mice and HSF1 transgenic mice using in vitro and in vivo techniques. We determined that while HSF1 expression was induced by anti-CD3 stimulation alone, the combination of anti-CD3 and TGFβ, a vital cytokine for regulatory T cell (Treg) development, resulted in increased activating phosphorylation of HSF1, leading to increased nuclear translocation and binding to heat shock response elements. Using ChIP, we demonstrate direct binding of HSF1 to foxp3 in isolated murine CD4+ T cells, which in turn coincided with induction of FoxP3 expression. We defined that conditional knockout of HSF1 decreased development and function of Tregs and overexpression of HSF1 led to increased expression of FoxP3 along with enhanced Treg suppressive function. Adoptive transfer of CD45RBHigh CD4 colitogenic T cells along with HSF1 transgenic CD25+ Tregs prevented intestinal inflammation when WT Tregs did not. Finally, overexpression of HSF1 provided enhanced barrier function and protection from murine ileitis. This study demonstrates that HSF1 promotes Treg development and function and may represent both a crucial step in the development of induced regulatory T cells and an exciting target for the treatment of inflammatory diseases with a regulatory T cell component.

Teriflunomide induces Foxp3 expression in murine CD8 + T cells while IL-27 and retinoic acid exert a synergistic effect on the induction of CD39 expression on these cells

Teriflunomide induces Foxp3 expression in murine CD8 + T cells while IL-27 and retinoic acid exert a synergistic effect on the induction of CD39 expression on these cells

Distinct functions and transcriptional signatures in orally induced regulatory T cell populations

Oral administration of antigen induces regulatory T cells (Treg) that can not only control local immune responses in the small intestine, but also traffic to the central immune system to deliver systemic suppression. Employing murine models of the inherited bleeding disorder hemophilia, we find that oral antigen administration induces three CD4+ Treg subsets, namely FoxP3+LAP-, FoxP3+LAP+, and FoxP3-LAP+. These T cells act in concert to suppress systemic antibody production induced by therapeutic protein administration. Whilst both FoxP3+LAP+ and FoxP3-LAP+ CD4+ T cells express membrane-bound TGF-β (latency associated peptide, LAP), phenotypic, functional, and single cell transcriptomic analyses reveal distinct characteristics in the two subsets. As judged by an increase in IL-2Rα and TCR signaling, elevated expression of co-inhibitory receptor molecules and upregulation of the TGFβ and IL-10 signaling pathways, FoxP3+LAP+ cells are an activated form of FoxP3+LAP- Treg. Whereas FoxP3-LAP+ cells express low levels of genes involved in TCR signaling or co-stimulation, engagement of the AP-1 complex members Jun/Fos and Atf3 is most prominent, consistent with potent IL-10 production. Single cell transcriptomic analysis further reveals that engagement of the Jun/Fos transcription factors is requisite for mediating TGFβ expression. This can occur via an Il2ra dependent or independent process in FoxP3+LAP+ or FoxP3-LAP+ cells respectively. Surprisingly, both FoxP3+LAP+ and FoxP3-LAP+ cells potently suppress and induce FoxP3 expression in CD4+ conventional T cells. In this process, FoxP3-LAP+ cells may themselves convert to FoxP3+ Treg. We conclude that orally induced suppression is dependent on multiple regulatory cell types with complementary and interconnected roles.

Activated protein C modulates T-cell metabolism and epigenetic FOXP3 induction via α-ketoglutarate.

A direct regulation of adaptive immunity by the coagulation protease activated protein C (aPC) has recently been established. Preincubation of T cells with aPC for 1 hour before transplantation increases FOXP3+ regulatory T cells (Tregs) and reduces acute graft-versus-host disease (aGVHD) in mice, but the underlying mechanism remains unknown. Because cellular metabolism modulates epigenetic gene regulation and plasticity in T cells, we hypothesized that aPC promotes FOXP3+ expression by altering T-cell metabolism. To this end, T-cell differentiation was assessed invitro using mixed lymphocyte reaction or plate-bound α-CD3/CD28 stimulation, and exvivo using T cells isolated from mice with aGVHD without and with aPC preincubation, or analyses of mice with high plasma aPC levels. In stimulated CD4+CD25- cells, aPC induces FOXP3 expression while reducing expression of T helper type 1 cell markers. Increased FOXP3 expression is associated with altered epigenetic markers (reduced 5-methylcytosine and H3K27me3) and reduced Foxp3 promoter methylation and activity. These changes are linked to metabolic quiescence, decreased glucose and glutamine uptake, decreased mitochondrial metabolism (reduced tricarboxylic acid metabolites and mitochondrial membrane potential), and decreased intracellular glutamine and α-ketoglutarate levels. In mice with high aPC plasma levels, T-cell subpopulations in the thymus are not altered, reflecting normal T-cell development, whereas FOXP3 expression in splenic T cells is reduced. Glutamine and α-ketoglutarate substitution reverse aPC-mediated FOXP3+ induction and abolish aPC-mediated suppression of allogeneic T-cell stimulation. These findings show that aPC modulates cellular metabolism in T cells, reducing glutamine and α-ketoglutarate levels, which results in altered epigenetic markers, Foxp3 promoter demethylation and induction of FOXP3 expression, thus favoring a Treg-like phenotype.

Lactobacillus rhamnosus reduces CD8+T cell mediated inflammation in patients with rheumatoid arthritis

BackgroundThe T cells, components of adaptive immunity participate in immune pathology of the autoimmune inflammatory disorder called rheumatoid arthritis (RA). The presence of TLRs on the surface of the CD8+ T cells and their ability to recognize bacterial moieties adds to the inflammatory burden in case of RA. It has been reported that the gut microbiome is necessary for the crucial shift in the balance between proinflammatory and anti-inflammatory cytokines. The altered gut microbiome and the presence of TLRs emphasizes on the microbiome driven inflammatory responses in case of RA. MethodsEighty-nine RA patients participated in this study. Clinical variations like disease duration, number of actively inflamed joints, number and type of bone deformities, CRP, RF, Anti-CCP, ESR, DAS 28 score were recorded for each patient. Co-culture of CD8+T cells and bacteria has been performed with proper culture condition. TLRs and inflammatory mediators’ expression level were checked by both qPCR and flow cytometry analysis. ResultsWe observed in the suppression of pro-inflammatory molecules like Granzyme B and IFNƳ and expression of TLR2 in CD8 + T cells upon treatment with Lactobacillus rhamnosus (L. rhamnosus). Moreover, L. rhamnosus activated CD8+T cells such that they could induce FOXP3 expression in CD4+T cells thereby skewing T cell population towards a regulatory phenotype. On the contrary, TLR4 engagement on CD8+T cell by Escherichia coli (E.coli) increased in inflammatory responses following ERK activation. ConclusionsThus, we conclude that L. rhamnosus can effectively suppress CD8+T cell mediated inflammation by a simultaneous decrease of Th1 cells that may potentiate better treatment modalities for RA.

How autoreactive thymocytes differentiate into regulatory versus effector CD4+ T cells after avoiding clonal deletion

Thymocytes bearing autoreactive T cell receptors (TCRs) are agonist-signaled by TCR/co-stimulatory molecules to either undergo clonal deletion or to differentiate into specialized regulatory T (Treg) or effector T (Teff) CD4+ cells. How these different fates are achieved during development remains poorly understood. We now document that deletion and differentiation are agonist-signaled at different times during thymic selection and that Treg and Teff cells both arise after clonal deletion as alternative lineage fates of agonist-signaled CD4+CD25+ precursors. Disruption of agonist signaling induces CD4+CD25+ precursors to initiate Foxp3 expression and become Treg cells, whereas persistent agonist signaling induces CD4+CD25+ precursors to become IL-2+ Teff cells. Notably, we discovered that transforming growth factor-β induces Foxp3 expression and promotes Treg cell development by disrupting weaker agonist signals and that Foxp3 expression is not induced by IL-2 except under non-physiological in vivo conditions. Thus, TCR signaling disruption versus persistence is a general mechanism of lineage fate determination in the thymus that directs development of agonist-signaled autoreactive thymocytes.

Propolis anti-inflammatory effects on MAGE-1 and retinoic acid-treated dendritic cells and on Th1 and T regulatory cells.

Propolis exhibits huge potential in the pharmaceutical industry. In the present study, its effects were investigated on dendritic cells (DCs) stimulated with a tumor antigen (MAGE-1) and retinoic acid (RA) and on T lymphocytes to observe a possible differential activation of T lymphocytes, driving preferentially to Th1 or Treg cells. Cell viability, lymphocyte proliferation, gene expression (T-bet and FoxP3), and cytokine production by DCs (TNF-α, IL-10, IL-6 and IL-1β) and lymphocytes (IFN-γ and TGF-β) were analyzed. MAGE-1 and RA alone or in combination with propolis inhibited TNF-α production and induced a higher lymphoproliferation compared to control, while MAGE-1 + propolis induced IL-6 production. Propolis in combination with RA induced FoxP3 expression. MAGE-1 induced IFN-γ production while propolis inhibited it, returning to basal levels. RA inhibited TGF-β production, what was counteracted by propolis. Propolis affected immunological parameters inhibiting pro-inflammatory cytokines and favoring the regulatory profile, opening perspectives for the control of inflammatory conditions.

Opposing Roles of DCs and iNKT Cells in the Induction of Foxp3 Expression by MLN CD25+CD4+ T Cells during IFNγ-Driven Colitis

We have previously shown that a deficiency of CD1d-restricted invariant natural killer T (iNKT) cells exacerbates dextran sulfate sodium (DSS)-induced colitis in Yeti mice that exhibit IFNγ-mediated hyper-inflammation. Although iNKT cell-deficiency resulted in reduced Foxp3 expression by mesenteric lymph node (MLN) CD4+ T cells in DSS-treated Yeti mice, the cellular mechanisms that regulate Foxp3 expression by CD25+CD4+ T cells during intestinal inflammation remain unclear. We found that Foxp3-CD25+CD4+ T cells expressing Th1 and Th17 phenotypic hallmarks preferentially expanded in the MLNs of DSS-treated Yeti/CD1d knockout (KO) mice. Moreover, adoptive transfer of Yeti iNKT cells into iNKT cell-deficient Jα18 KO mice effectively suppressed the expansion of MLN Foxp3-CD25+CD4+ T cells during DSS-induced colitis. Interestingly, MLN dendritic cells (DCs) purified from DSS-treated Yeti/CD1d KO mice promoted the differentiation of naive CD4+ T cells into Foxp3-CD25+CD4+ T cells rather than regulatory T (Treg) cells, indicating that MLN DCs might mediate Foxp3+CD25+CD4+ T cell expansion in iNKT cell-sufficient Yeti mice. Furthermore, we showed that Foxp3-CD25+CD4+ T cells were pathogenic in DSS-treated Yeti/CD1d KO mice. Our result suggests that pro-inflammatory DCs and CD1d-restricted iNKT cells play opposing roles in Foxp3 expression by MLN CD25+CD4+ T cells during IFNγ-mediated intestinal inflammation, with potential therapeutic implications.

IPSC-Derived HLA-A2 CAR Tregs Showed Suppression of GvHD in a Xenograft Model

Overcoming pathologies caused by excessive immunity, such as graft-versus-host disease (GvHD) after hematopoietic stem cell transplantation and autoimmune diseases such as type1 diabetes and inflammatory bowel disease, is a challenge for medical research. It has been reported that CD4 single positive helper T cells can be induced from iPS cells (iPS-CD4Ts) by organoid culture using Notch ligand-expressing cells. However, these cells are conventional helper T cells (Tconvs) that secrete inflammatory cytokines such as IFN-γ or IL-4 if they are not treated in any way. Now, we report that we have succeeded in inducing FOXP3, a marker of immunosuppressive regulatory T cells (Tregs), in these iPS-CD4Ts at a high rate by combining compounds and cytokines. We used CDK8/19 inhibitor(A), TNFR2 antibody(M), Rapamycin(R), and TGF-β(T). Therefore, we named this process the AMRT. AMRT-treated iPS-CD4Ts didn't secrete inflammatory cytokines even under strong stimulus conditions. And, these cells were accompanied by demethylation of the Treg-specific demethylation region (TSDR), which suggested stable conversion to immunosuppressive cells. Furthermore, the combination of compounds and cytokines that induced FOXP3 expression in iPSC-derived Tconvs and converted them to FOXP3+ cells can also be used to amplify primary natural Tregs (nTregs) while retaining FOXP3. Comprehensive gene expression analysis (Ampliseq) showed close profiling of primary nTregs and AMRT-treated iPS-CD4Ts. These AMRT-treated iPS-CD4Ts were assessed functionally by CAR-mediated immunosuppressive ability. We evaluated the ability of these iPSC-derived HLA-A2 CAR-transduced FOXP3+ T cells to inhibit CTL division in mixed lymphocyte reaction (MLR) assays with HLA-A2+ allo CTLs. AMRT-treated iPS-CD4Ts showed CTL division suppression ability beyond primary nTregs. Surprisingly, this suppressive capacity was independent of the induction of CAR. If proximity is guaranteed in advance, the bystander suppression effect may be sufficient. We then assessed the immunosuppressive capacity of these cells through the extent to which they could suppress the xenograft GvHD that human HLA-A2+ PBMCs cause in NSG mice. AMRT-treated HLA-A2 CAR-transduced iPS-CD4Ts showed a survival benefit comparable to that of primary nTregs. In contrast to the invitro results, the invivo immunosuppressive capacity was CAR-specific. In summary, we have successfully generated large numbers of immune-suppressing regulatory T cells from iPS cells to suppress GvHD. This is a groundbreaking achievement that paves the way for curative therapies for GvHD and autoimmune diseases. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Paeonia lactiflora Pallas extract alleviates antibiotics and DNCB-induced atopic dermatitis symptoms by suppressing inflammation and changing the gut microbiota composition in mice

Atopic dermatitis (AD) is a highly prevalent inflammatory skin disease worldwide. Recent studies have suggested an important role for association with the gut and skin microbiome axis in AD development. Paeonia lactiflora Pallas extract (PL) is commonly used for the treatment of inflammatory diseases. However, the possible mechanisms by which PL can alleviate AD by regulating the gut microbiota have not been investigated. In this study, we aimed to investigate the therapeutic effects and underlying mechanism of PL in mice with antibiotic cocktail (ABX)-induced AD. The effects of PL were evaluated in bone marrow-derived macrophages (BMDMs) and ABX and dinitrochlorobenzene (DNCB) mouse models. PL suppressed inflammatory cytokine and NO production in LPS-treated BMDMs. Moreover, PL attenuated scoring atopic dermatitis (SCORAD) scores, epidermal thickness, white blood cell counts and the disease activity index (DAI) in ABX-induced AD mice. Meanwhile, PL decreased IL-17A production, induced Foxp3 expression and improved intestinal barrier integrity by especially increasing the expression of tight junction proteins such as ZO-1 and occludin. Additionally, PL partially increased the diversity of the gut microbiota and changed the microbial composition. Our findings suggest that PL may be a potential natural product that can ameliorate atopic dermatitis symptoms by suppressing inflammatory cytokine production, inducing Foxp3 expression, increasing intestinal barrier integrity and changing the gut microbiota composition.

Lactoferrin-derived chimeric peptide (LFch) strongly boosts TGFβ1-mediated inducible Treg differentiation possibly through downregulating TCR/CD28 signalling.

We recently reported that lactoferrin (LF) induces Foxp3+ Treg differentiation through binding to TGFβ receptor III (TβRIII), and this activity was further enhanced by TGFβ1. Generally, a low T-cell receptor (TCR) signal strength is favourable for Foxp3+ Treg differentiation. In the present study, we explored the effect of lactoferrin chimera (LFch, containing lactoferricin [aa 17-30] and lactoferrampin [aa 265-284]), along with TGFβ1 on Foxp3+ Treg differentiation. LFch alone did not induce Foxp3 expression, yet LFch dramatically enhanced TGFβ1-induced Foxp3 expression. LFch had little effect on the phosphorylation of Smad3, a canonical transcriptional factor of TGFβ1. Instead, LFch attenuated the phosphorylation of S6 (a target of mTOR), IκB and PI3K. These activities of LFch were completely abrogated by pretreatment of LFch with soluble TGFβ1 receptor III (sTβRIII). Consistent with this, the activity of LFch on TGFβ1-induced Foxp3 expression was also abrogated by treatment with sTβRIII. Finally, the TGFβ1/LFch-induced T cell population substantially suppressed the proliferation of responder CD4+ T cells. These results indicate that LFch robustly enhances TGFβ1-induced Foxp3+ Treg differentiation by diminishing TCR/CD28 signal intensity.

Exosomal B7–H4 from irradiated glioblastoma cells contributes to increase FoxP3 expression of differentiating Th1 cells and promotes tumor growth

BackgroundGlioblastoma (GBM) is the most common and aggressive form of primary brain tumor. Although numerous postoperative therapeutic strategies have already been developed, including radiotherapy, tumors inevitably recur after several years of treatment. The coinhibitory molecule B7–H4 negatively regulates T cell immune responses and promotes immune escape. Exosomes mediate intercellular communication and initiate immune evasion in the tumor microenvironment (TME). ObjectiveThis study aimed to determine whether B7–H4 is upregulated by radiation and loaded into exosomes, thus contributing to immunosuppression and enhancing tumor growth. MethodsIodixanol density-gradient centrifugation and flow cytometry were used to verify exosomal B7–H4. Naïve T cells were differentiated into Th1 cells, with or without exosomes. T cell-secreted cytokines and markers of T cell subsets were measured. Mechanistically, the roles of B7–H4, and ALIX in GBM were analyzed using databases and tissue samples. Co‐immunoprecipitation, and pull-down assays were used to tested the direct interactions between ATM and ALIX or STAT3. In vitro ATM kinase assays, western blotting, and site-directed mutation were used to assess ATM-mediated STAT3 phosphorylation. Finally, the contribution of exosomal B7–H4 to immunosuppression and tumor growth was investigated in vivo. ResultsExosomes from irradiated GBM cells decreased the anti-tumor immune response of T cell in vitro and in vivo via delivered B7–H4. Mechanistically, irradiation promoted exosome biogenesis by increasing the ATM-ALIX interaction. Furthermore, the ATM-phosphorylated STAT3 was found to directly binds to the B7–H4 promoter to increase its expression. Finally, the radiation-induced increase in exosomal B7–H4 induced FoxP3 expression during Th1 cell differentiation via the activated STAT1 pathway. In vivo, exosomal B7–H4 decreased the radiation sensitivity of GBM cells, and reduced the survival of GBM mice model. ConclusionThis study showed that radiation-enhanced exosomal B7–H4 promoted immunosuppression and tumor growth, hence defining a direct link between irradiation and anti-tumor immune responses. Our results suggest that co-administration of radiotherapy with anti-B7-H4 therapy could improve local tumor control and identify exosomal B7–H4 as a potential tumor biomarker.

A Combination of Cytokine-Induced Killer Cells With PD-1 Blockade and ALK Inhibitor Showed Substantial Intrinsic Variability Across Non-Small Cell Lung Cancer Cell Lines.

BackgroundCancer heterogeneity poses a serious challenge concerning the toxicity and adverse effects of therapeutic inhibitors, especially when it comes to combinatorial therapies that involve multiple targeted inhibitors. In particular, in non-small cell lung cancer (NSCLC), a number of studies have reported synergistic effects of drug combinations in the preclinical models, while they were only partially successful in the clinical setup, suggesting those alternative clinical strategies (with genetic background and immune response) should be considered. Herein, we investigated the antitumor effect of cytokine-induced killer (CIK) cells in combination with ALK and PD-1 inhibitors in vitro on genetically variable NSCLC cell lines.MethodsWe co-cultured the three genetically different NSCLC cell lines NCI-H2228 (EML4-ALK), A549 (KRAS mutation), and HCC-78 (ROS1 rearrangement) with and without nivolumab (PD-1 inhibitor) and crizotinib (ALK inhibitor). Additionally, we profiled the variability of surface expression multiple immune checkpoints, the concentration of absolute dead cells, intracellular granzyme B on CIK cells using flow cytometry as well as RT-qPCR. ELISA and Western blot were performed to verify the activation of CIK cells.ResultsOur analysis showed that (a) nivolumab significantly weakened PD-1 surface expression on CIK cells without impacting other immune checkpoints or PD-1 mRNA expression, (b) this combination strategy showed an effective response on cell viability, IFN-γ production, and intracellular release of granzyme B in CD3+ CD56+ CIK cells, but solely in NCI-H2228, (c) the intrinsic expression of Fas ligand (FasL) as a T-cell activation marker in CIK cells was upregulated by this additive effect, and (d) nivolumab induced Foxp3 expression in CD4+CD25+ subpopulation of CIK cells significantly increased. Taken together, we could show that CIK cells in combination with crizotinib and nivolumab can enhance the anti-tumor immune response through FasL activation, leading to increased IFN-γ and granzyme B, but only in NCI-H2228 cells with EML4-ALK rearrangement. Therefore, we hypothesize that CIK therapy may be a potential alternative in NSCLC patients harboring EML4-ALK rearrangement, in addition, we support the idea that combination therapies offer significant potential when they are optimized on a patient-by-patient basis.

Lactoferrin-derived Chimeric Peptide (LFch) boosts TGFβ1-induced Treg Differentiation by diminishing of TCR Signal intensity via TβRIII

Abstract Regulatory T cells (Tregs) are a special subset of T cells to suppress excessive immune response and maintain immunologic tolerance. It is known that lesser TCR signal strength is favorable for Foxp3+ Treg differentiation. We recently reported that LF substantially promoted Foxp3 expression by activated CD4+ T cells and this activity was further enhanced by TGF-β1. In the present study, we explored the effect of lactoferrin chimera (LFch, synthetic LF-derived chimeric peptides) along with TGFβ1 on Foxp3+ Treg differentiation. LFch itself did not induce Foxp3 expression. However, LFch dramatically enhanced TGFβ1-induced Foxp3 expression. LFch little affected the phosphorylation of Smad3, which is a canonical TGF-β1 mediator. Instead, LFch decreased the phosphorylation of S6, IkB, and PI3 kinase (an activation hallmark of TCR signaling). These effects of LFch were completely abolished by pretreatment of LFch with soluble TβRIII. Consistently, the enhancement of TGFβ1-induced Foxp3 by LFch was also abrogated by treatment of soluble TβRIII. Finally, TGFβ1/LFch-induced T cell population substantially suppressed the proliferation of responder CD4+ T cells. These results indicate that LFch potently enhances TGFβ1-induced Foxp3+ Treg differentiation by diminishing TCR signal intensity through TβRIII.

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

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

The Defect in Regulatory T Cells in Psoriasis and Therapeutic Approaches

Psoriasis is a chronic inflammatory skin disease characterized by accelerated tumor necrosis factor-α/interleukin (IL)-23/IL-17 axis. Patients with psoriasis manifest functional defects in CD4+CD25+ forkhead box protein 3 (Foxp3)+ regulatory T cells (Tregs), which suppress the excess immune response and mediate homeostasis. Defects in Tregs contribute to the pathogenesis of psoriasis and may attribute to enhanced inhibition and/or impaired stimulation of Tregs. IL-23 induces the conversion of Tregs into type 17 helper T (Th17) cells. IL-17A reduces transforming growth factor (TGF)-β1 production, Foxp3 expression, and suppresses Treg activity. Short-chain fatty acids (SCFAs), butyrate, propionate, and acetate are microbiota-derived fermentation products that promote Treg development and function by inducing Foxp3 expression or inducing dendritic cells or intestinal epithelial cells to produce retinoic acids or TGF-β1, respectively. The gut microbiome of patients with psoriasis revealed reduced SCFA-producing bacteria, Bacteroidetes, and Faecallibacterium, which may contribute to the defect in Tregs. Therapeutic agents currently used, viz., anti-IL-23p19 or anti-IL-17A antibodies, retinoids, vitamin D3, dimethyl fumarate, narrow-band ultraviolet B, or those under development for psoriasis, viz., signal transducer and activator of transcription 3 inhibitors, butyrate, histone deacetylase inhibitors, and probiotics/prebiotics restore the defected Tregs. Thus, restoration of Tregs is a promising therapeutic target for psoriasis.

Interleukin 32 Promotes Foxp3+ Treg Cell Development and CD8+ T Cell Function in Human Esophageal Squamous Cell Carcinoma Microenvironment.

Proinflammatory cytokine interleukin 32 (IL-32) is involved in infectious diseases and cancer, but what subtypes of immune cells express IL-32 and its roles in tumor microenvironment (TME) have not been well discussed. In this study, we applied bioinformatics to analyze single-cell RNA sequencing data about tumor-infiltrating immune cells from esophageal squamous cell carcinoma (ESCC) TME and analyzed IL-32 expression in different immune cell types. We found CD4+ regulatory T cells (Treg cells) express the highest level of IL-32, while proliferating T and natural killer cells expressed relatively lower levels. Knocking down of IL-32 reduced Foxp3 and interferon gamma (IFNγ) expressions in CD4+ and CD8+ T cells, respectively. IL-32 was positively correlated with Foxp3, IFNG, and GZMB expression but was negatively correlated with proliferation score. IL-32 may have a contradictory role in the TME such as it promotes IFNγ expression in CD8+ T cells, which enhances the antitumor activity, but at the same time induces Foxp3 expression in CD4+ T cells, which suppresses the tumor immune response. Our results demonstrate different roles of IL-32 in Treg cells and CD8+ T cells and suggest that it can potentially be a target for ESCC cancer immunosuppressive therapy.

Regulation of autoreactive CD4 T cells by FoxO1 signaling in CNS autoimmunity

Myelin-specific CD4 T effector cells (Teffs), Th1 and Th17 cells, are encephalitogenic in experimental autoimmune encephalomyelitis (EAE), a well-defined murine model of multiple sclerosis (MS) and implicated in MS pathogenesis. Forkhead box O 1 (FoxO1) is a conserved effector molecule in PI3K/Akt signaling and critical in the differentiation of CD4 T cells into T helper subsets. However, it is unclear whether FoxO1 may be a target for redirecting CD4 T cell differentiation and benefit CNS autoimmunity. Using a selective FoxO1 inhibitor AS1842856, we show that inhibition of FoxO1 suppressed the differentiation and expansion of Th1 cells. The transdifferentiation of Th17 cells into encephalitogenic Th1-like cells was suppressed by FoxO1 inhibition upon reactivation of myelin-specific CD4 T cells from EAE mice. The transcriptional balance skewed from the Th1 transcription factor T-bet toward the Treg transcription factor Foxp3. Myelin-specific CD4 T cells treated with the FoxO1 inhibitor were less encephalitogenic in adoptive transfer EAE studies. Inhibition of FoxO1 in T cells from MS patients significantly suppressed the expansion of Th1 cells. Furthermore, FoxO1 inhibition with AS1842856 promoted the development of functional iTreg cells. The immune checkpoint programmed cell death protein-1 (PD-1)-induced Foxp3 expression in CD4 T cells was impaired by FoxO1 inhibition. These data illustrate an important role of FoxO1 signaling in CNS autoimmunity via regulating autoreactive Teff and Treg balance.

Induction of Foxp3 and Activation of Regulatory T Cells by Heat Shock Protein Gp96 for Treatment of Autoimmune Diseases

Utilizing regulatory T cells (Treg) is a promising approach for treating autoimmune diseases, including systemic lupus erythematosus (SLE) and rheumatic diseases. Upregulation and stabilization of forkhead box P3 (Foxp3) expression in Tregs are essential for regulating Treg function and immune homeostasis. In this study, we examined the potential effect and mechanism of heat shock protein gp96 in regulating Foxp3 expression and Treg activation in vivo. High-dose gp96 immunization showed obvious therapeutic effects in a Lyn-/- mouse model of SLE, as evidenced by decreased auto-antibody titers, follicular helper T cells, and antibody-production plasma cells. Moreover, immunization of mice with gp96 alleviated the initiation and progression of myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis (EAE). Immunization of gp96 increased Treg frequency, expansion, and suppressive function with no obvious effector T cell activation. Gene expression profiling was used to identify the NF-κB family member p65 and c-Rel as the key transcription factors for enhanced Foxp3 expression in Treg by gp96. Mutant gp96 within its Toll-like receptor (TLR) binding domain, TLR2 knockout (KO) mice, and mice with cell-specific deletion of MyD88, were used to demonstrate that gp96 activated Tregs and induced Foxp3 expression via a TLR2-MyD88-mediated NF-κB signaling pathway. Taken together, these results show that gp96 immunization restricted antibody- and Th-induced autoimmune diseases by integrating Treg expansion and activation, indicating its potential clinical usefulness against autoimmune diseases.