'Yin-Yang' functions of transforming growth factor-beta and T regulatory cells in immune regulation

Similarities between the Yin/Yang Doctrine and Hormesis in Toxicology and Pharmacology

Hormesis is a generalizable dose-response relationship characterized by low-dose stimulation and high-dose inhibition. Despite debate over this biphasic dose-response curve, hormesis is challenging central beliefs in the evaluation of chemicals or drugs and has influenced biological model selection, concentration range, study design, and hypothesis testing. We integrate the traditional Chinese philosophy - Yin/Yang doctrine - into the representation of the Western hormetic dose-response relationship and review the Yin/Yang historical philosophy contained in the hormesis concept, aiming to promote general acceptance and wider applications of hormesis. We suggest that the Yin/Yang doctrine embodies the hormetic dose-response, including the relationship between the opposing components, curve shape, and time-dependence, and may afford insights that clarify the hormetic dose-response relationship in toxicology and pharmacology.

Altered expression of nuclear factor of activated T cells, forkhead box P3, and immune-suppressive genes in regulatory T cells of generalized vitiligo patients

The study was aimed to analyze expression of nuclear factor of activated T cells (NFATs), forkhead box P3 (FOXP3), and their associated genes (sCTLA4, flCTLA4, IL10, TGFB, IL2, IL4, CD25) in regulatory T cells (Tregs) of 48 generalized vitiligo (GV) patients and 45 unaffected controls. The transcripts of NFATC1 to NFATC4, FOXP3, IL10, flCTLA4 (p < .0001), NFAT5 (p = .0003), sCTLA4 (p = .001), and FOXP3 protein in Tregs and plasma IL-10 levels were reduced significantly (p < .0001) in GV Tregs compared to controls. The FOXP3 promoter polymorphisms [rs3761548(C > A), rs3761547(A > G), and rs2232365(A > G)] revealed significantly decreased FOXP3 protein levels in patients' Tregs with susceptible AA, GG, and GG genotypes (p < .0001, p = .028, p = .022, respectively). The active vitiligo Tregs showed reduced levels of NFATC3, NFATC4, NFAT5, FOXP3, TGFB, and flCTLA4 transcripts (p = .0005, p = .0003, p = .0002, p = .020, p < .0001, p = .006, respectively) and FOXP3 and TGF-β proteins (p = .0394 and p = .0013) compared to stable vitiligo. Early-onset patients (1-20 years) demonstrated decreased IL-10, sCTLA-4, flCTLA-4, TGFB, and FOXP3 transcripts and FOXP3 protein as compared to late-onset patients (41-60 years) (p = .001, p = .003, p = .009, p = .005, p = .038, p = .0226, respectively). Overall, our results for the first time suggest a likely role of NFATs and FOXP3 together with Treg immune-suppressive genes in GV pathogenesis and disease progression, warranting additional investigations.

Inhibition of Histone Deacetylase (HDAC) Enhances Checkpoint Blockade Efficacy by Rendering Bladder Cancer Cells Visible for T Cell-Mediated Destruction

Inhibitory checkpoint blockade therapy is an immunomodulatory strategy that results in the restoration of T cell functions, and its efficacy depends on the recognition of tumor cells for destruction. Considering the factors at play, one could propose that anti-tumor responses will not occur if tumor cells are immunologically invisible to T cells. In this study, we tested a strategy based on the modulation of cancer cell's immunovisibility through HDAC inhibition. In a model (heterotopic and orthotopic) of mouse urothelial bladder cancer, we demonstrated that the use of intratumoral or intravesical HDACi in combination with systemic anti-PD-1 was effective at inducing curative responses with durable anti-tumor immunity capable of preventing tumor growth at a distal site. Mechanistically, we determined that protective responses were dependent on CD8 cells, but not NK cells. Of significance, in an in vitro human model, we found that fully activated T cells fail at killing bladder cancer cells unless tumor cells were pretreated with HDACi. Complementary to this observation, we found that HDACi cause gene deregulation, that results in the upregulation of genes responsible for mediating immunorecognition, NKG2D ligands and HSP70. Taken together, these data indicate that HDAC inhibition results in the elimination of the tumor cell's “invisibility cloak” that prevents T cells from recognizing and killing them. Finally, as checkpoint blockade therapy moves into the adjuvant setting, its combined use with locally administrated HDACi represents a new approach to be included in our current therapeutic treatment toolbox.

Immune modulation by complement receptor 3-dependent human monocyte TGF-β1-transporting vesicles

Extracellular vesicles have an important function in cellular communication. Here, we show that human and mouse monocytes release TGF-β1-transporting vesicles in response to the pathogenic fungus Candida albicans. Soluble β-glucan from C. albicans binds to complement receptor 3 (CR3, also known as CD11b/CD18) on monocytes and induces the release of TGF-β1-transporting vesicles. CR3-dependence is demonstrated using CR3-deficient (CD11b knockout) monocytes generated by CRISPR-CAS9 genome editing and isolated from CR3-deficient (CD11b knockout) mice. These vesicles reduce the pro-inflammatory response in human M1-macrophages as well as in whole blood. Binding of the vesicle-transported TGF-β1 to the TGF-β receptor inhibits IL1B transcription via the SMAD7 pathway in whole blood and induces TGFB1 transcription in endothelial cells, which is resolved upon TGF-β1 inhibition. Notably, human complement-opsonized apoptotic bodies induce production of similar TGF-β1-transporting vesicles in monocytes, suggesting that the early immune response might be suppressed through this CR3-dependent anti-inflammatory vesicle pathway.

Immunomodulatory Strategies Targeting Dendritic Cells to Improve Corneal Graft Survival

Even though the cornea is regarded as an immune-privileged tissue, transplantation always comes with the risk of rejection due to mismatches between donor and recipient. It is common sense that an alternative to corticosteroids as the current gold standard for treatment of corneal transplantation is needed. Since blood and lymphatic vessels have been identified as a severe risk factor for corneal allograft survival, much research has focused on vessel regression or inhibition of hem- and lymphangiogenesis in general. However, lymphatic vessels have been identified as required for the inflammation's resolution. Therefore, targeting other players of corneal engraftment could reveal new therapeutic strategies. The establishment of a tolerogenic microenvironment at the graft site would leave the recipient with the ability to manage pathogenic conditions independent from transplantation. Dendritic cells (DCs) as the central player of the immune system represent a target that allows the induction of tolerogenic mechanisms by many different strategies. These strategies are reviewed in this article with regard to their success in corneal transplantation.

Immunoregulatory Potential of Exosomes Derived from Cancer Stem Cells

Head and neck squamous cell carcinomas (HNSCCs) are malignancies that originate in the mucosal lining of the upper aerodigestive tract. Despite advances in therapeutic interventions, survival rates among HNSCC patients have remained static for years. Cancer stem cells (CSCs) are tumor-initiating cells that are highly resistant to treatment, and are hypothesized to contribute to a significant fraction of tumor recurrences. Consequently, further investigations of how CSCs mediate recurrence may provide insights into novel druggable targets. A key element of recurrence involves the tumor's ability to evade immunosurveillance. Recent published reports suggest that CSCs possess immunosuppressive properties, however, the underlying mechanism have yet to be fully elucidated. To date, most groups have focused on the role of CSC-derived secretory proteins, such as cytokines and growth factors. Here, we review the established immunoregulatory role of exosomes derived from mixed tumor cell populations, and propose further study of CSC-derived exosomes may be warranted. Such studies may yield novel insights into new druggable targets, or lay the foundation for future exosome-based diagnostics.

Potential role of NF-κB pathway in the immuno-inflammatory responses during human cystic echinococcosis

Cystic echinococcosis (CE) induces in the human host innate and adaptive immune response that plays an important role in controlling the immunopathogenesis. Due to the crucial role of nuclear factor kappa B (NF-κB) in regulating immuno-inflammatory processes, we investigated its potential contribution in systemic and local immuno-inflammatory responses in primary CE patients and relapsed patients. The expression of NF-κB and inducible nitric oxide synthase (iNOS) was analyzed in peripheral blood mononuclear cells (PBMC) as well as in pericystic layer of pulmonary hydatid cysts from Algerian primary CE patients and relapsed patients. Tumor necrosis factor alpha (TNF-α) and nitric oxide (NO) production was evaluated in plasma samples. Our results showed high iNOS and NF-κB expression in both PBMCs and pericystic histiocytes from primary CE patients. In addition, substantial amounts of systemic NO and TNF-α were detected in the same patients. Remarkably, relapsed patients exhibited a low NF-κB and iNOS expression associated with low amounts of plasmatic TNF-α and NO. Collectively, NF-κB/iNOS pathway is involved in the host defense mechanisms at the systemic and local level during primary CE. Our results indicate that the inhibition of this pathway in relapsed patients will attenuate protective immunity and promote parasite escape. This study allowed to identify a novel predictive biomarkers of hydatidosis.

Mutation in Fbxo11 Leads to Altered Immune Cell Content in Jeff Mouse Model of Otitis Media

The Jeff mouse mutant carries a mutation in the F-box only 11 gene (Fbxo11) and heterozygous animals display conductive deafness due to the development of otitis media (OM). The Fbxo11 locus is also associated with chronic otitis media with effusion (COME) and recurrent OM in humans. The Jeff mutation affects the ability of FBXO11 to stabilize p53 that leads to perturbation in the TGF-beta/Smad2 signaling pathway important in immunity and inflammation. In the current study, we evaluated the effect of the Jeff mutation on the immune cell content using multicolor flow cytometry. In blood of Jeff heterozygotes, we observed a significant increase in the number of NK, dendritic (CD11b+), neutrophils, and natural killer T (NKT) cells and a significant decrease in effector T-helper and B-lymphocytes compared to wild-type controls. The percentage of NK cells significantly decreased in the lungs of Jeff heterozygotes, with a concomitant reduction in B-lymphocytes and T-cytotoxic cells. In the spleen, Jeff heterozygotes displayed a significant decrease in mature B-lymphocytes, effector T-helper, and naïve T-cytotoxic cells. Neutrophils, dendritic, and NKT cells dominated bulla fluid in Jeff heterozygote mice. Similar analysis carried out on Fbxo11^tm2b/+ heterozygotes, which carry a null allele, showed no difference when compared to wild-type. Cytokine/chemokine analysis revealed a significant increase in the G-CSF, GM-CSF, sTNFRI, TPO, and IL-7 levels in Jeff heterozygote serum compared to wild-type. This analysis increases our understanding of the role played by Fbxo11, a gene associated with human OM, in the systemic and localized cellular immune response associated with increased susceptibility to OM.

Significance of TC9 and TH9 in Helicobacter pylori-induced gastritis

BACKGROUND

H pylori plays a critical role in the development of stomach cancer, especially in people affected by the bacteria at an early stage of life. Th9 cells and IL-9 play major roles in immune responses against various infections. IL-9 is influential in chronic or acute inflammation of the mucosa.

AIM

This study seeks to investigate the possible functions of Tc9, Th9 cells, and IL-9 level in patients with inflammation due to H pylori infection.

METHODS

Eighty-three patients with dyspepsia symptoms and twenty normal subjects with no sign and symptoms of dyspepsia were recruited. Frequencies of T-cell subsets were determined by flow cytometry. Levels of cytokines IL-9 family in the sera and supernatants of antigen-activated PBMCs patients were measured by ELISA and flow cytometry.

RESULTS

The participants included 56 females and 47 males with a mean age of 39.2 ± 15.3 years. We assigned the infected group into peptic ulcer and gastritis (chronic active and chronic). Frequencies of Tc9, Th17, Tc17, Th17/9, and Tc17/9 increased significantly in the peptic ulcer, chronic active, and chronic gastritis, compared with the uninfected and healthy control groups. A significant increase was seen in IL-9, IL-4, and IL-23 in the chronic active gastritis. Further observed was a significant increase in IL-21 and a decrease in IL-10 in the infected groups.

CONCLUSION

The results revealed that increased Tc9, Th17/9, and Tc17/9 cells appear to be influential in the progression and severity of H pylori infection. Also, increased IL-9 and IL-4 levels and Tc9, Tc17/9, and Th17/9 were seen in chronic active gastritis patients. These findings may provide useful information for a therapeutic targeting of chronic active H pylori infections.

Deep Infiltrating Endometriosis and Activation and Memory Surface Markers and Cytokine Expression in Isolated Treg Cells

It is not yet clear whether regulatory T (Treg) cells are active, and whether they play a favorable or adverse effect on endometrial foci implantation. Our aim was to evaluate activation and memory surface markers in Treg isolated from peritoneal fluid (PF) and peripheral blood (PB) of women with deep endometriosis and to assess its cytokine mRNA expression. This case-control study included 49 women with deep infiltrating endometriosis and 20 healthy controls. It was analyzed PF and PB of both groups. Cell surface markers GITR, TNFRII, HLA-DR, ICOS, CTLA-4, CD45RA, and CD45RO were evaluated in Treg (CD3⁺CD4⁺CD25⁺CD127^lowFoxp3⁺) cells by flow cytometry. Additionally, Foxp3, TGF-beta, IL-10, IL-6, and TNF-alpha mRNA expression was assessed by real-time PCR in Treg cells (CD4⁺CD25⁺CD127^dim/-) isolated using magnetic microbeads. Women with endometriosis had higher percentages of TNFRII+ Treg and CTLA-4+ Treg in their PB, and lower percentages of ICOS+ Treg and CD45RO+ Treg in their PF. The groups displayed no differences in mRNA expression. Regardless of the group, in PF, the percentage of Treg cells overall and of CD45RA+ Treg cells were significantly lower, whereas the percentage of TNFRII+ Treg and CD45RO+ Treg were significantly higher than in PB. Foxp3 and TGF-beta mRNA expression were also higher in PF than in PB. Our results indicated that Treg cells in women with endometriosis have a distinct profile of activation and memory markers, but similar cytokine expression. Moreover, we could observe clearly that Treg cells have distinct profile regarding their origin site.

NHC-gold compounds mediate immune suppression through induction of AHR-TGFβ1 signalling in vitro and in scurfy mice

Gold compounds have a long history of use as immunosuppressants, but their precise mechanism of action is not completely understood. Using our recently developed liver-on-a-chip platform we now show that gold compounds containing planar N-heterocyclic carbene (NHC) ligands are potent ligands for the aryl hydrocarbon receptor (AHR). Further studies showed that the lead compound (MC3) activates TGFβ1 signaling and suppresses CD4+ T-cell activation in vitro, in human and mouse T cells. Conversely, genetic knockdown or chemical inhibition of AHR activity or of TGFβ1-SMAD-mediated signaling offsets the MC3-mediated immunosuppression. In scurfy mice, a mouse model of human immunodysregulation polyendocrinopathy enteropathy X-linked syndrome, MC3 treatment reduced autoimmune phenotypes and extended lifespan from 24 to 58 days. Our findings suggest that the immunosuppressive activity of gold compounds can be improved by introducing planar NHC ligands to activate the AHR-associated immunosuppressive pathway, thus expanding their potential clinical application for autoimmune diseases.

Immune Th17 lymphocytes play a critical role in the multiple beneficial properties of resveratrol

Modulation of the inflammatory response is one of the major issues of the 21st century due to its importance in the occurrence of various pathologies (cancer, autoimmune diseases, degenerative diseases) and their progression over time. Whether acute or chronic, the inflammatory response is directly related to the immune response through different subtypes of T lymphocytes. In addition, among the compounds capable of modulating the cells of the immune system, resveratrol, a polyphenol with pleiotropic biological properties, seems to be a good candidate. Indeed, resveratrol is able to alter the immune response by modulating the process of lymphocyte differentiation and subsequently diminishing the inflammatory-associated response. More specifically, thanks to its ability to act as a sirtuin-1 agonist, it can deacetylate the transcription factor STAT3 and alter nuclear factors essential to the process of lymphocyte differentiation. We present and discuss these different aspects in relation to various pathologies and how the alteration of the ratios between the different lymphocyte subtypes by resveratrol is an important element to take into account when studying its anti-inflammatory and immunomodulatory properties.

The Cross Talk between Cancer Stem Cells/Cancer Initiating Cells and Tumor Microenvironment: The Missing Piece of the Puzzle for the Efficient Targeting of these Cells with Immunotherapy

Cancer Stem Cells/Cancer Initiating Cells (CSCs/CICs) is a rare sub-population within a tumor that is responsible for tumor formation, progression and resistance to therapies. The interaction between CSCs/CICs and tumor microenvironment (TME) can sustain “stemness” properties and promote their survival and plasticity. This cross-talk is also pivotal in regulating and modulating CSC/CIC properties. This review will provide an overview of the mechanisms underlying the mutual interaction between CSCs/CICs and TME. Particular focus will be dedicated to the immunological profile of CSCs/CICs and its role in orchestrating cancer immunosurveillance. Moreover, the available immunotherapy strategies that can target CSCs/CICs and of their possible implementation will be discussed. Overall, the dissection of the mechanisms regulating the CSC/CIC-TME interaction is warranted to understand the plasticity and immunoregulatory properties of stem-like tumor cells and to achieve complete eradications of tumors through the optimization of immunotherapy.

Dendritic Cells Control Regulatory T Cell Function Required for Maintenance of Intestinal Tissue Homeostasis

Dendritic cells (DCs) together with regulatory T cells (Tregs) are essential mediators of immune homeostasis. Disruption of function or frequency of either cell type can lead to fatal autoimmunity. We previously described that mice constitutively lacking DCs (∆DC) develop autoimmunity characterized by reduced body weight, autoantibodies, and pronounced intestinal inflammation. In this study, we show that lack of DCs leads to an altered gene expression profile in peripheral but not thymic Tregs with increased expression of inhibitory receptors. The suppressive function of Tregs from ΔDC mice was impaired in T cell cocultures. In a model of transfer colitis, Tregs from ∆DC mice were only functional in the presence of DCs in recipient mice. Lack of MHC class II on DCs also resulted in upregulation of inhibitory receptors on Tregs, reduced body weight, and elevated serum IgA levels. Further analysis of the IgA response revealed an expansion of IgA⁺ germinal center B cells and plasma cells in mesenteric lymph nodes and more IgA-coated commensal bacteria in feces of ∆DC mice. Thus, we show a critical role for DCs to establish intestinal homeostasis by regulating Treg function for prevention of spontaneous inflammation.

The Deubiquitinating Enzyme Ubiquitin-Specific Peptidase 11 Potentiates TGF-β Signaling in CD4+ T Cells to Facilitate Foxp3+ Regulatory T and TH17 Cell Differentiation

Foxp3⁺ regulatory T (T_REG) cells are central mediators in the control of peripheral immune responses. Genome-wide transcriptional profiles show canonical signatures for Foxp3⁺ T_REG cells, distinguishing them from Foxp3^- effector T (T_EFF) cells. We previously uncovered distinct mRNA translational signatures differentiating CD4⁺ T_EFF and T_REG cells through parallel measurements of cytosolic (global) and polysome-associated (translationally enhanced) mRNA levels in both subsets. We show that the mRNA encoding for the ubiquitin-specific peptidase 11 (USP11), a known modulator of TGF-β signaling, was preferentially translated in TCR-activated T_REG cells compared with conventional, murine CD4⁺ T cells. TGF-β is a key cytokine driving the induction and maintenance of Foxp3 expression in T cells. We hypothesized that differential translation of USP11 mRNA endows T_REG cells with an advantage to respond to TGF-β signals. In an in vivo mouse model promoting T_REG cells plasticity, we found that USP11 protein was expressed at elevated levels in stable T_REG cells, whereas ectopic USP11 expression enhanced the suppressive capacity and lineage commitment of these cells in vitro and in vivo. USP11 overexpression in T_EFF cells enhanced the activation of the TGF-β pathway and promoted T_REG or T_H17, but not Th1, cell differentiation in vitro and in vivo, an effect abrogated by USP11 gene silencing or the inhibition of enzymatic activity. Thus, USP11 potentiates TGF-β signaling in both T_REG and T_EFF cells, in turn driving increased suppressive function and lineage commitment in thymic-derived T_REG cells and potentiating the TGF-β-dependent differentiation of T_EFF cells to peripherally induced T_REG and T_H17 cells.

VAMP8-mediated MUC2 mucin exocytosis from colonic goblet cells maintains innate intestinal homeostasis

The mucus layer is the first line of innate host defense in the gut that protects the epithelium by spatially separating commensal bacteria. MUC2 mucin is produced and stored by goblet cells that is constitutively exocytosed or hyper secreted upon sensing a threat. How coordinated mucus exocytosis maintains homeostasis in the intestinal epithelium and modulates the immunological landscape remains elusive. Here we describe how the vesicle SNARE protein VAMP8 coordinates mucin exocytosis from goblet cells. Vamp8^-/- exhibit a mild pro-inflammatory state basally due to an altered mucus layer and increased encounters with microbial antigens. Microbial diversity shifts to a detrimental microbiota with an increase abundance of pathogenic and mucolytic bacteria. To alleviate the heavy microbial burden and inflammatory state basally, Vamp8^-/- skews towards tolerance. Despite this, Vamp8^-/- is highly susceptible to both chemical and infectious colitis demonstrating the fragility of the intestinal mucosa without proper mucus exocytosis mechanisms.

Oral delivery of pancreatitis-associated protein by Lactococcus lactis displays protective effects in dinitro-benzenesulfonic-acid-induced colitis model and is able to modulate the composition of the microbiota

Antimicrobial peptides secreted by intestinal immune and epithelial cells are important effectors of innate immunity. They play an essential role in the maintenance of intestinal homeostasis by limiting microbial epithelium interactions and preventing unnecessary microbe‐driven inflammation. Pancreatitis‐associated protein (PAP) belongs to Regenerating islet‐derived III proteins family and is a C‐type (Ca⁺² dependent) lectin. PAP protein plays a protective effect presenting anti‐inflammatory properties able to reduce the severity of colitis, preserving gut barrier and epithelial inflammation. Here, we sought to determine whether PAP delivered at intestinal lumen by recombinant Lactococcus lactis strain (LL‐PAP) before and after chemically induced colitis is able to reduce the severity in two models of colitis. After construction and characterization of our recombinant strains, we tested their effects in dinitro‐benzenesulfonic‐acid (DNBS) and Dextran sulfate sodium (DSS) colitis model. After the DNBS challenge, mice treated with LL‐PAP presented less severe colitis compared with PBS and LL‐empty‐treated mice groups. After the DSS challenge, no protective effects of LL‐PAP could be detected. We determined that after 5 days administration, LL‐PAP increase butyrate producer's bacteria, especially Eubacterium plexicaudatum. Based on our findings, we hypothesize that a treatment with LL‐PAP shifts the microbiota preventing the severity of colon inflammation in DNBS colitis model. These protective roles of LL‐PAP in DNBS colitis model might be through intestinal microbiota modulation.

Insights into the HIV Latency and the Role of Cytokines

Human immunodeficiency virus-1 (HIV-1) has the ability to infect latently at the level of individual CD4+ cells. Latent HIV-1 proviruses are transcriptionally silent and immunologically inert, but are still capable of reactivating productive lytic infection following cellular activation. These latent viruses are the main obstacle in the eradication of HIV-1, because current HIV-1 treatment regimens are ineffective against them. Normal immunological response against an antigen activates CD4+ naïve T cells. The activated CD4+ naïve T cells undergo cell cycle, resulting in further transformation and profound proliferation to form effector CD4+ T-cells. Notably, in HIV-1 infected individuals, some of the effector CD4+ T cells get infected with HIV-1. Upon fulfillment of their effector functions, almost all activated CD4+ T cells are committed to apoptosis or programmed cell death, but a miniscule fraction revert to quiescence and become resting memory CD4+ T cells to mediate a rapid immunological response against the same antigen in the future. However, due to the quiescent nature of the resting memory T cells, the integrated HIV-1 becomes transcriptionally silent and acquires a latent phenotype. Following re-exposure to the same antigen, memory cells and integrated HIV-1 are stimulated. The reactivated latent HIV provirus subsequently proceeds through its life cycle and eventually leads to the production of new viral progeny. Recently, many strategies against HIV-1 latency have been developed and some of them have even matured to the clinical level, but none can yet effectively eliminate the latent HIV reservoir, which remains a barrier to HIV-1 cure. Therefore, alternative strategies to eradicate latent HIV need to be considered. This review provides vital knowledge on HIV latency and on strategies to supplement highly active anti-retroviral therapy (HAART) with cytokine-mediated therapeutics for dislodging the latent HIV reservoirs in order to open up new avenues for curing HIV.

The rs3761548 FOXP3 variant is associated with multiple sclerosis and transforming growth factor β1 levels in female patients

OBJECTIVE

The aim of this study was to evaluate the association between rs3761548 FOXP3 (-3279 C > A) variant and multiple sclerosis (MS), disability, disability progression, as well as transforming growth factor (TGF)-β1 and interleukin (IL)-10 plasma levels in MS patients.

METHODS AND SUBJECTS

The study included 170 MS patients and 182 controls. Disability was evaluated using Expanded Disability Status Scale (EDSS) and categorized as mild (EDSS ≤ 3) and moderate/high (EDSS > 3). Disability progression was evaluated using Multiple Sclerosis Severity Score (MSSS). The rs3761548 variant was determined with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Plasma levels of TGF-β1 and IL-10 were determined using immunofluorimetric assay.

RESULTS

CA and AA genotypes were associated with MS [odds ratio (OR) 2.03, 95% confidence interval (CI) 1.66-3.53, p = 0.012; OR 8.19, 95% CI 3.04-22.07, p < 0.001, respectively). With the dominant model, the CA + AA genotypes were associated with MS (OR 2.57, 95% CI 1.50-4.37, p < 0.001). In the recessive model, the AA genotype was also associated with MS (OR 5.38, 95% CI 2.12-13.64, p < 0.001). After adjustment by age, ethnicity, BMI and smoking, all these results remained significant, as well as female patients carrying the CA + AA genotypes showed higher TGF-β1 than those carrying the CC genotype (OR 1.35, 95% CI 1.001-1.054, p = 0.043). No association was observed between the genotypes and disability, disability progression and IL-10 levels.

CONCLUSION

These results suggest that the A allele of FOXP3 -3279 C > A variant may exert a role in the T regulatory cell function, which could be one of the factors involved in the susceptibility for MS in females.

Blockade of TGF-β signaling to enhance the antitumor response is accompanied by dysregulation of the functional activity of CD4+CD25+Foxp3+ and CD4+CD25-Foxp3+ T cells

Background

The pleiotropic cytokine, transforming growth factor (TGF)-β, and CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Tregs) play a critical role in actively suppressing antitumor immune responses. Evidence shows that TGF-β produced by tumor cells promotes tolerance via expansion of Tregs. Our group previously demonstrated that blockade of TGF-β signaling with a small molecule TGF-β receptor I antagonist (SM16) inhibited primary and metastatic tumor growth in a T cell dependent fashion. In the current study, we evaluated the effect of SM16 on Treg generation and function.

Methods

Using BALB/c, FoxP3eGFP and Rag^−/− mice, we performed FACS analysis to determine if SM16 blocked de novo TGF-β-induced Treg generation in vitro and in vivo. CD4⁺ T cells from lymph node and spleen were isolated from control mice or mice maintained on SM16 diet, and flow cytometry analysis was used to detect the frequency of CD4⁺CD25⁻FoxP3⁺ and CD4⁺CD25⁺FoxP3⁺ T cells. In vitro suppression assays were used to determine the ability to suppress naive T cell proliferation in vitro of both CD4⁺CD25⁺FoxP3⁺ and CD4⁺CD25⁻FoxP3⁺ T cell sub-populations. We then examined whether SM16 diet exerted an inhibitory effect on primary tumor growth and correlated with changes in FoxP3⁺expression. ELISA analysis was used to measure IFN-γ levels after 72 h co-culture of CD4⁺CD25⁺ T cells from tumor-bearing mice on control or SM16 diet with CD4⁺CD25⁻ T cells from naive donors.

Results

SM16 abrogates TGF-β-induced Treg generation in vitro but does not prevent global homeostatic expansion of CD4⁺ T cell sub-populations in vivo. Instead, SM16 treatment causes expansion of a population of CD4⁺CD25⁻Foxp3⁺ Treg-like cells without significantly altering the overall frequency of Treg in lymphoreplete naive and tumor-bearing mice. Importantly, both the CD4⁺CD25⁻Foxp3⁺ T cells and the CD4⁺CD25⁺Foxp3⁺ Tregs in mice receiving SM16 diet exhibited diminished ability to suppress naive T cell proliferation in vitro compared to Treg from mice on control diet.

Conclusions

These findings suggest that blockade of TGF-β signaling is a potentially useful strategy for blunting Treg function to enhance the anti-tumor response. Our data further suggest that the overall dampening of Treg function may involve the expansion of a quiescent Treg precursor population, which is CD4⁺CD25⁻Foxp3⁺.

Thrombospondin-1 in ocular surface health and disease

Thrombospondin 1 (TSP-1) is an extracellular matrix protein that interacts with a wide array of ligands including cell receptors, growth factors, cytokines and proteases to regulate various physiological and pathological processes. Constitutively expressed by certain ocular surface tissues (e.g. corneal and conjunctival epithelium), TSP-1 expression is modulated during ocular surface inflammation. TSP-1 is an important activator of latent TGF-β, serving to promote the immunomodulatory and wound healing functions of TGF-β. Mounting research has deepened our understanding of how TSP-1 expression (and lack thereof) contributes to ocular surface homeostasis and disease. Here, we review current knowledge of the function of TSP-1 in dry eye disease, ocular allergy, angiogenesis/lymphangiogenesis, corneal transplantation, corneal wound healing and infectious keratitis.

Thrombopoietin receptor agonists: ten years later

The two thrombopoietin receptor agonists (TPO-RA), eltrombopag and romiplostim, were licensed in the US for treatment of immune thrombocytopenia (ITP) in 2008 and, since then, their use has progressively increased around the world; they are currently used in more than 100 countries. The six largest randomized controlled trials conducted in ITP have used one of these two agents. All studies have demonstrated a platelet response rate between 50-90%, depending on the criteria used, with good safety and tolerability. TPO-RA were shown to be effective in reducing bleeding and the need for concomitant or rescue medication. Many other investigations of their mechanism of effect, prospective and retrospective trials, and studies focusing on toxicity have been performed widening our knowledge of these two agents. Initial concerns on issues such as myelofibrosis have not been confirmed. Only a small number of patients develop moderate-severe reticulin fibrosis and/or collagen fibrosis; however, these are usually reversed after discontinuation of TPO-RA. Studies indicate, however, that TPO-RA may increase the risk of venous thromboembolism. Both TPO-RA are currently approved in patients with chronic ITP aged >1-year who are refractory to at least one other treatment. Eltrombopag has acquired two additional indications: severe aplastic anemia refractory to first-line treatment and hepatitis C patients undergoing treatment with interferon-ribavirin. Despite these wide-ranging studies, important questions still need to be answered. This summary review on TPO-RA will summarize what is known regarding efficacy in ITP, evaluate safety concerns in more depth, and focus on the questions that remain.

Linked CD4 T Cell Help: Broadening Immune Attack Against Cancer by Vaccination

In the last decade, immunotherapy with monoclonal antibodies targeting immunological check points has become a breakthrough therapeutic modality for solid cancers. However, only up to 50 % of patients benefit from this powerful approach. For others vaccination might provide a plausible addition or alternative. For induction of effective anticancer immunity CD4+ T cell help is required, which is often difficult to induce to self cancer targets because of tolerogenic mechanisms. Our approach for cancer vaccines has been to incorporate into the vaccine design sequences able to activate foreign T cell help, through genetically linking cancer targets to microbial sequences (King et al. in Nat Med 4(11):1281-1286, 1998; Savelyeva et al. in Nat Biotechnol 19(8):760-764, 2001). This harnesses the non-tolerized CD4 T cell repertoire available in patients to help induction of effective immunity against fused cancer antigens. Multiple immune effector mechanisms including antibody, CD8+ T cells as well as CD4 effector T cells can be activated using this strategy. Delivery via DNA vaccines has already indicated clinical efficacy. The same principle of linked T cell help has now been transferred to other novel vaccine modalities to further potentiate immunity against cancer targets.

Polymorphisms in IL-10 and TGF-β gene promoter are associated with lower risk to gastric cancer in a Mexican population

BACKGROUND

Helicobacter pylori infection is recognized as the main risk factor for gastric cancer (GC), the fifth most common neoplasia worldwide. H. pylori interacts with the immune system, disrupting the cytokine network and inducing chronic inflammation. This work aimed to evaluate the association between single nucleotide polymorphisms (SNPs) in selected cytokine gene promoters and GC.

METHODS

The study included 359 subjects, 125 GC patients, 109 intestinal metaplasia (IM) patients and 125 asymptomatic controls. DNA was extracted from white blood cells and nine SNPs in cytokine gene promoters were genotyped using predesigned 5'-endonulease assays. The association of the SNPs with IM and GC was evaluated using multinomial regression models.

RESULTS

Both genotypes, TC (OR = 0.51, 95% CI = 0.27-0.98) and TT (OR = 0.42, 95% CI = 0.20-0.91) in the locus - 509 of the TGF-β promoter were significantly associated with GC. The TT genotype in the locus - 819 of the IL-10 promoter was also significantly associated with GC (OR = 0.37, 95% CI = 0.17-0.81). No significant association was found with SNPs IL-4 -590 T/C (rs1800629), IL-6 -573G/C (rs1800796), IL-10 -592C/A (rs1800872), IL-10 -1082A/G (rs1800896), and, IFN-γ -1615C/T (rs2069705).

CONCLUSIONS

SNPs in TGFβ (- 509 C/T, rs1800469) and IL-10 (- 819 C/T, rs1800871) promoters were associated with a lower risk for GC in a Mexican population.

Mevalonate promotes differentiation of regulatory T cells

Mevalonate is a precursor in a biosynthetic pathway that is important for the coordination of regulatory T cell (Treg) proliferation and upregulation of the suppressive function that establishes the functional competency of Tregs. The extensive role of mevalonate and its underlying effect on Treg differentiation are still unclear. We found that mevalonate increases in vitro differentiation of induced Tregs (iTregs) without broadly affecting Th1 and Th17 cell differentiation. Furthermore, an adoptive transfer study showed that mevalonate enhanced peripherally induced Treg cells (pTregs) in mesenteric lymphocytes in vivo. Mevalonate-treated iTregs exhibited greater suppressive activity against effector cells than untreated Tregs. Mechanistically, mevalonate enhanced transforming growth factor (TGF)-β signaling by increasing the phosphorylation of Smad3, but not Smad2, and by promoting Foxp3 expression. Furthermore, we demonstrated that mevalonate treatment ameliorated dextran sulfate sodium (DSS)-induced colitis and resulted in an increased percentage of Tregs in vivo. Our results suggest that mevalonate enhanced Treg differentiation and ameliorated DSS colitis, indicating its potential for treatment of inflammatory diseases.

MicroRNA-92 Expression in CD133+ Melanoma Stem Cells Regulates Immunosuppression in the Tumor Microenvironment via Integrin-Dependent Activation of TGFβ

In addition to being refractory to treatment, melanoma cancer stem cells (CSC) are known to suppress host antitumor immunity, the underlying mechanisms of which need further elucidation. In this study, we established a novel role for miR-92 and its associated gene networks in immunosuppression. CSCs were isolated from the B16-F10 murine melanoma cell line based on expression of the putative CSC marker CD133 (Prominin-1). CD133⁺ cells were functionally distinct from CD133^- cells and showed increased proliferation in vitro and enhanced tumorigenesis in vivo. CD133⁺ CSCs also exhibited a greater capacity to recruit immunosuppressive cell types during tumor formation, including FoxP3⁺ Tregs, myeloid-derived suppressor cells (MDSC), and M2 macrophages. Using microarray technology, we identified several miRs that were significantly downregulated in CD133⁺ cells compared with CD133^- cells, including miR-92. Decreased expression of miR-92 in CSCs led to higher expression of target molecules integrin α_V and α₅ subunits, which, in turn, enhanced TGFβ activation, as evidenced by increased phosphorylation of SMAD2. CD133⁺ cells transfected with miR-92a mimic and injected in vivo showed significantly decreased tumor burden, which was associated with reduced immunosuppressive phenotype intratumorally. Using The Cancer Genome Atlas database of patients with melanoma, we also noted a positive correlation between integrin α₅ and TGFβ1 expression levels and an inverse association between miR-92 expression and integrin alpha subunit expression. Collectively, this study suggests that a miR-92-driven signaling axis involving integrin activation of TGFβ in CSCs promotes enhanced tumorigenesis through induction of intratumoral immunosuppression. SIGNIFICANCE: CD133⁺ cells play an active role in suppressing melanoma antitumor immunity by modulating miR-92, which increases influx of immunosuppressive cells and TGFβ1 expression.

Combined Inhibition of TGF-β Signaling and the PD-L1 Immune Checkpoint Is Differentially Effective in Tumor Models

Antibodies blocking the programmed death-ligand 1 (PD-L1) have shown impressive and durable responses in clinical studies. However, this type of immunotherapy is only effective in a subset of patients and not sufficient for rejection of all tumor types. In this study, we explored in two mouse tumor models whether the antitumor effect could be enhanced by the combined blockade of PD-L1 and transforming growth factor-β (TGF-β), a potent immunosuppressive cytokine. The effect of anti-PD-L1 mouse monoclonal (mAb) and a TGF-β type I receptor small molecule kinase inhibitor (LY364947) was evaluated in the highly immunogenic mouse MC38 colon adenocarcinoma and the poorly immunogenic mouse KPC1 pancreatic tumor model. In the MC38 tumor model, LY364947 monotherapy did not show any antitumor effect, whereas treatment with anti-PD-L1 mAb significantly delayed tumor outgrowth. However, combination therapy showed the strongest therapeutic efficacy, resulting in improved long-term survival compared with anti-PD-L1 mAb monotherapy. This improved survival was associated with an increased influx of CD8⁺ T cells in the tumor microenvironment. In the KPC1 tumor model, LY364947 did not enhance the antitumor effect of anti-PD-L1 mAb. Despite this, delayed KPC1 tumor outgrowth was observed in the LY364947-treated group and this treatment led to a significant reduction of CD4⁺ T cells in the tumor microenvironment. Together, our data indicate that an additive anti-tumor response of dual targeting PD-L1 and TGF-β is dependent on the tumor model used, highlighting the importance of selecting appropriate cancer types, using in-depth analysis of the tumor microenvironment, which can benefit from combinatorial immunotherapy regimens.

Impaired Tip60-mediated Foxp3 acetylation attenuates regulatory T cell development in rheumatoid arthritis

In rheumatoid arthritis (RA), imbalanced T cells subsets play a critical role in sustaining chronic inflammatory responses in the synovium. Naïve T cells in RA patients undergo maldifferentiation, including an increase in the effector Th1/Th17 lineage and a reduction in regulatory T (Treg) cells. Upon stimulation, naïve CD4⁺CD45RO^- T cells from RA patients exhibited insufficient expression of Foxp3, which induced a deficiency in Tregs production and an imbalance of Treg/Th17 differentiation. Further mechanistic study indicated that RA T cells failed to produce sufficient levels of the histone acetyltransferase Tip60, leading to reduced acetylation of Foxp3; this, in turn, decreased Foxp3 expression, impaired Treg commitment, and promoted Th17 production. Moreover, in human synovium chimeric mice, suppression of Tip60 activity in healthy T cells promoted tissue infiltration and arthritogenesis, while reconstitution of Tip60 in RA T cells suppressed synovitis and effector T cell infiltration. Our findings link T cell maldifferentiation and tissue infiltration with Tip60-mediated Foxp3 acetylation and identify Tip60 as a potential therapeutic target for suppression of tissue inflammation and autoimmunogenesis in RA.

Soluble CD83 Triggers Resolution of Arthritis and Sustained Inflammation Control in IDO Dependent Manner

Interference with autoimmune-mediated cytokine production is a key yet poorly developed approach to treat autoimmune and inflammatory diseases such as rheumatoid arthritis. Herein, we show that soluble CD83 (sCD83) enhances the resolution of autoimmune antigen-induced arthritis (AIA) by strongly reducing the expression levels of cytokines such as IL-17A, IFNγ, IL-6, and TNFα within the joints. Noteworthy, also the expression of RANKL, osteoclast differentiation, and joint destruction was significantly inhibited by sCD83. In addition, osteoclasts which were cultured in the presence of synovial T cells, derived from sCD83 treated AIA mice, showed a strongly reduced number of multinuclear large osteoclasts compared to mock controls. Enhanced resolution of arthritis by sCD83 was mechanistically based on IDO, since inhibition of IDO by 1-methyltryptophan completely abrogated sCD83 effects on AIA. Blocking experiments, using anti-TGF-β antibodies further revealed that also TGF-β is mechanistically involved in the sCD83 induced reduction of bone destruction and cartilage damage as well as enhanced resolution of inflammation. Resolution of arthritis was associated with increased numbers of regulatory T cells, which are induced in a sCD83-IDO-TGF-β dependent manner. Taken together, sCD83 represents an interesting approach for downregulating cytokine production, inducing regulatory T cells and inducing resolution of autoimmune arthritis.

An injectable bone marrow-like scaffold enhances T cell immunity after hematopoietic stem cell transplantation

The use of allogeneic hematopoietic stem cell transplantation (HSCT) to cure multiple disorders is limited by deficiency and dysregulation of T-cells. Here we report a biomaterial-based scaffold that mimics features of T-cell lymphopoiesis in the bone marrow. The bone marrow cryogel (BMC) releases bone morphogenetic protein-2 to recruit stromal cells, and presents the Notch ligand Delta-like ligand-4 to facilitate T-cell lineage specification of mouse and human hematopoietic progenitor cells. BMCs subcutaneously injected in mice at the time of HSCT enhanced T-cell progenitor seeding of the thymus, T-cell neogenesis and diversification of the T-cell receptor repertoire. Peripheral T-cell reconstitution increased ~6-fold in mouse HSCT and ~2-fold in human xenogeneic HSCT. Furthermore, BMCs promoted donor CD4⁺ regulatory T-cell generation and improved survival after allogeneic HSCT. Compared with adoptive transfer of T-cell progenitors, BMCs increased donor chimerism, T-cell generation and antigen-specific T-cell responses to vaccination. BMCs may provide an off-the-shelf approach for enhancing T-cell regeneration and mitigating graft-versus-host disease in HSCT.

Inhibitory role of transforming growth factor β2 in experimental autoimmune anterior uveitis

PURPOSE

Experimental autoimmune anterior uveitis (EAAU) is a clinically relevant animal model for human idiopathic anterior uveitis (IAU). The role of the immunomodulator transforming growth factor β2 (TGF-β2) in EAAU pathology is unknown. In this study, we investigated the regulatory role of TGF-β2 in EAAU.

METHODS

EAAU was induced in male Lewis rats by footpad injection of melanin-associated antigen (MAA). TGF-β2 was administered intravenously (iv) in MAA-sensitized rats during the induction of EAAU, or after the clinical onset of uveitis. MAA-sensitized rats injected similarly with an equal volume of PBS served as control. Animals were examined daily between days 7 and 30 post-injection for the clinical signs of uveitis using slit lamp biomicroscopy. Animals were sacrificed at various time points and eyes were harvested for histological analysis to assess the course and severity of inflammation. For histopathological analysis, paraffin sections of harvested eyes were stained with hematoxylin and eosin. Popliteal lymph nodes (LNs) were used for CD4⁺CD25⁺FoxP3⁺ T regulatory (Tregs) population analysis and for CD4⁺ T cell proliferation assay.

RESULTS

Administration of recombinant TGF-β2 during the early stages of EAAU prevented the induction of uveitis. Compared to PBS, the presence of TGF-β2 in the cell culture significantly (p < 0.05) inhibited the proliferation of CD4⁺ T cells in response to MAA. In MAA-sensitized Lewis rats, iv treatment with recombinant TGF-β2 resulted in significantly (p < 0.05) increased percentage of Tregs compared to animals treated similarly with PBS. Thus, TGF-β2 inhibited the induction of EAAU by inhibiting CD4⁺ T cell proliferation and increasing the number of Tregs. Injection of TGF-β2 in rats with active EAAU resulted in diminished disease activity. Unfortunately, this treatment did not lead to the early resolution of EAAU.

CONCLUSIONS

TGF-β2 plays a critical role in regulation of intraocular inflammation in EAAU. Findings reported in this study improve our understanding of immunopathology of IAU and suggest that recombinant TGF-β2 may be a promising therapeutic agent for human IAU.

Megakaryocytes as immune cells

Platelets play well-recognized roles in inflammation, but their cell of origin-the megakaryocyte-is not typically considered an immune lineage. Megakaryocytes are large polyploid cells most commonly identified in bone marrow. Egress via sinusoids enables migration to the pulmonary capillary bed, where elaboration of platelets can continue. Beyond receptors involved in hemostasis and thrombosis, megakaryocytes express receptors that confer immune sensing capacity, including TLRs and Fc-γ receptors. They control the proliferation of hematopoietic cells, facilitate neutrophil egress from marrow, possess the capacity to cross-present antigen, and can promote systemic inflammation through microparticles rich in IL-1. Megakaryocytes internalize other hematopoietic lineages, especially neutrophils, in an intriguing cell-in-cell interaction termed emperipolesis. Together, these observations implicate megakaryocytes as direct participants in inflammation and immunity.

Novel Immunoregulatory Functions of IL-18, an Accomplice of TGF-β1

TGF-β1 is a pleiotropic factor exerting a strong regulatory role in several cell types, including immune cells. In NK cells it profoundly alters the surface expression of crucial activating and chemokine receptors. To understand which soluble signals might better contrast these effects, we cultured human NK cells in the presence of TGF-β1 and different innate and adaptive cytokines, generally referred as “immunostimulatory”. These included IL-2, IL-15, IL-21, IL-27, and IL-18. Unexpectedly, IL-18 strengthened rather than contrasting important TGF-β1-mediated functions. In particular, IL-18 further reduced the expression of CX₃CR1 and NKp30, leading to the virtual abrogation of the triggering capability of this activating receptor. Moreover, IL-18 further increased the expression of CXCR4. The IL-18-mediated additive effect on NKp30 and CXCR4 expression involved transcriptional regulation and activation of MEK/ERK and/or p38MAPK. A proteomic approach quantified both surface and intracellular proteins significantly modified in cytokine-treated NK cells, thus giving global information on the biological processes involving TGF-β1 and IL-18. Our data support the concept that IL-18 may have a different behavior depending on the type of soluble factors characterizing the microenvironment. In a TGF-β1 rich milieu such as tumors, it may contribute to the impairment of both NK cells recruitment and killing capability.

Sialylation of vasorin by ST3Gal1 facilitates TGF-β1-mediated tumor angiogenesis and progression

ST3Gal1 is a key sialyltransferase which adds α2,3‐linked sialic acid to substrates and generates core 1 O‐glycan structure. Upregulation of ST3Gal1 has been associated with worse prognosis of breast cancer patients. However, the protein substrates of ST3Gal1 implicated in tumor progression remain elusive. In our study, we demonstrated that ST3GAL1‐silencing significantly reduced tumor growth along with a notable decrease in vascularity of MCF7 xenograft tumors. We identified vasorin (VASN) which was shown to bind TGF‐β1, as a potential candidate that links ST3Gal1 to angiogenesis. LC‐MS/MS analysis of VASN secreted from MCF7, revealed that more than 80% of its O‐glycans are sialyl‐3T and disialyl‐T. ST3GAL1‐silencing or desialylation of VASN by neuraminidase enhanced its binding to TGF‐β1 by 2‐ to 3‐fold and thereby dampening TGF‐β1 signaling and angiogenesis, as indicated by impaired tube formation of HUVECs, suppressed angiogenesis gene expression and reduced activation of Smad2 and Smad3 in HUVEC cells. Examination of 114 fresh primary breast cancer and their adjacent normal tissues showed that the expression levels of ST3Gal1 and TGFB1 were high in tumor part and the expression of two genes was positively correlated. Kaplan Meier survival analysis showed a significantly shorter relapse‐free survival for those with lower expression VASN, notably, the combination of low VASN with high ST3GAL1 yielded even higher risk of recurrence (p = 0.025, HR = 2.967, 95% CI = 1.14–7.67). Since TGF‐β1 is known to transcriptionally activate ST3Gal1, our findings illustrated a feedback regulatory loop in which TGF‐β1 upregulates ST3Gal1 to circumvent the negative impact of VASN.

What's new?

The addition of sialic acid to glycoproteins is dysregulated in many cancers, and enhanced expression of one key enzyme, the sialyltransferase ST3Gal1, is associated with poor prognosis. Here, the authors identified the membrane protein vasorin as a new ST3Gal1 substrate and connect it with TGF‐β1‐induced signaling and angiogenesis in breast cancer. As silencing of ST3Gal1 dampened TGF‐β1 signaling and suppressed angiogenesis, development of ST3Gal1 inhibitors might be clinically useful to improve the prognosis of breast cancer patients.

Resveratrol Attenuates Allergic Asthma and Associated Inflammation in the Lungs Through Regulation of miRNA-34a That Targets FoxP3 in Mice

Asthma is a chronic inflammatory disease of airways mediated by T-helper 2 (Th2) cells involving complex signaling pathways. Although resveratrol has previously been shown to attenuate allergic asthma, the role of miRNA in this process has not been studied. We investigated the effect of resveratrol on ovalbumin-induced experimental allergic asthma in mice. To that end, BALB/c mice were immunized with ovalbumin (OVA) intraperitoneally followed by oral gavage of vehicle (OVA-veh) or resveratrol (100 mg/kg body) (OVA-res). On day 7, the experimental groups received intranasal challenge of OVA followed by 7 days of additional oral gavage of vehicle or resveratrol. At day 15, all mice were euthanized and bronchioalveolar fluid (BALF), serum and lung infiltrating cells were collected and analyzed. The data showed that resveratrol significantly reduced IL-5, IL-13, and TGF-β in the serum and BALF in mice with OVA-induced asthma. Also, we saw a decrease in CD3+CD4+, CD3+CD8+, and CD4+IL-4+ cells with increase in CD4+CD25+FOXP3+ cells in pulmonary inflammatory cell infiltrate in OVA-res group when compared to OVA-veh. miRNA expression arrays using lung infiltrating cells showed that resveratrol caused significant alterations in miRNA expression, specifically downregulating the expression of miR-34a. Additionally, miR-34a was found to target FOXP3, as evidenced by enhanced expression of FOXP3 in the lung tissue. Also, transfection studies showed that miR-34a inhibitor upregulated FOXP3 expression while miR-34a-mimic downregulated FOXP3 expression. The current study suggests that resveratrol attenuates allergic asthma by downregulating miR-34a that induces increased expression of FOXP3, a master regulator of Treg development and functions.

Assessment of soluble cytotoxic T lymphocyte-associated antigen-4, transforming growth factor β1, and platelet-derived microparticles during dasatinib therapy for patients with chronic myelogenous leukemia

BACKGROUND

The outcome for chronic myelogenous leukemia (CML) patients presented in the chronic phase has changed dramatically since the introduction of tyrosine kinase inhibitor (TKI) therapy. Notably, an increased incidence of large granular lymphocytes (LGLs), which is related to immunological conditions, appears to be predictive of a favorable outcome for dasatinib therapy. We therefore examined the immunological characteristics of CML patients during dasatinib therapy by determining the plasma concentrations of five different biomarkers.

METHODS

The plasma levels of biomarkers, specifically interleukin-6, platelet-derived microparticles (PDMPs), soluble vascular cell adhesion molecule 1 (sVCAM-1), transforming growth factor (TGF) β1, and soluble cytotoxic T lymphocyte-associated antigen-4 (sCTLA-4), were measured by ELISA at baseline and after 2 and 6 months of TKI treatment. The incidence of LGLs was estimated by microscopic examination.

RESULTS

The levels of PDMPs, sVCAM-1, and TGFβ1 were significantly elevated in patients with CML. Dasatinib treatment was associated with a significant reduction in the levels of these markers and with an increased incidence of LGLs compared with imatinib or nilotinib treatment. In addition, an increased incidence of LGLs was significantly correlated with a decreased sCTLA-4 level during dasatinib therapy.

CONCLUSION

The assessment of the levels of specific biomarkers may be beneficial to understand the immunological conditions of patients with CML during dasatinib treatment.

Regulatory T cell modulation of cytokine and cellular networks in corneal graft rejection

PURPOSE OF REVIEW

Corneal allografts placed in vascularized or inflamed host beds are at increased risk of graft rejection due to the preponderance of activated immune cells in the host bed. Regulatory T cells (Tregs) are master regulators of the adaptive immune response and play a key role in the induction of immune tolerance. The aim of this review is to discuss mechanisms through which Tregs mediate tolerance in corneal transplantation and the novel therapeutic approaches that target Tregs to promote transplant survival.

RECENT FINDINGS

The inflammatory environment of high-risk allografts not only promotes activation of effector T cells and their infiltration to graft site, but also impairs Treg immunomodulatory function. Recent studies have shown that expansion of Tregs and enhancing their modulatory function significantly improve graft survival.

SUMMARY

As our understanding of the cellular and molecular pathways in corneal transplantation has deepened, novel therapeutic strategies have been developed to improve allograft survival. In this review, we discuss therapeutic approaches that focus on Tregs to promote corneal allograft survival.

Tissue Resident CD8 Memory T Cell Responses in Cancer and Autoimmunity

Resident memory (T_RM) cells are a distinct tissue-localized T cell lineage that is crucial for protective immunity in peripheral tissues. While a great deal of effort has focused on defining their role in immunity to infections, studies now reveal T_RM cells as a vital component of the host immune response to cancer. Characterized by cell-surface molecules including CD103, CD69, and CD49a, T_RM-like tumor-infiltrating lymphocytes (TILs) can be found in a wide range of human cancers, where they portend improved prognosis. Recent studies in mouse tumor models have shown that T_RM cells are induced by cancer vaccines delivered in peripheral tissue sites, or by the depletion of regulatory T cells. Such tumor-specific T_RM cells are recognized as both necessary and sufficient for long-lived protection against tumors in peripheral tissue locations. T_RM responses against tumor/self-antigens can concurrently result in the development of pathogenic T_RM responses to self, with a growing number of autoimmune diseases and inflammatory pathologies being attributed to T_RM responses. This review will recount the path to discovering the importance of resident memory CD8 T cells as they pertain to cancer immunity. In addition to highlighting key studies that directly implicate T_RM cells in anti-tumor immunity, we will highlight earlier work that implicitly suggested their importance. Informed by studies in infectious disease models, and instructed by a clear role for T_RM cells in autoimmunity, we will discuss strategies for therapeutically promoting T_RM responses in settings where they don't naturally occur.

Role of Regulatory T Cells in Noninherited Maternal Antigen-Related Tolerance in Cord Blood: An in Vitro Study

Cord blood (CB) is an alternative stem cell source for allogeneic hematopoietic stem cell transplantation (HSCT). The unique advantages of using CB as a stem cell source are a degree of permissibility for HLA mismatch, rapid availability, and relatively risk-free cell collection. Because HLA is highly polymorphic and population-specific, optimal HLA-matched unrelated donors or cord blood units (CBUs) might not be available. In view of the possibility that matched CBUs that include noninherited maternal antigens (NIMAs) might contain acceptable HLA mismatches, we attempted to determine the degree of alloreactivity of CB mononuclear cells (MNCs) on stimulation by the maternal, paternal, and unrelated stimulator cells. Suppression of T cell proliferation, cytotoxicity, and a cytokine profile indicating suppressed Th1 and elevated IL-10 and TGF-β1 responses were observed in the mixed lymphocyte reaction in response to NIMAs. The increases in IL-10 and TGF-β1 production may be due to the Th2 response and/or regulatory T cells (Tregs). The reduced IL-10 and TGF-β1 production after CD25 depletion could have been due to removal of Tregs from the CB cells. Thus, Tregs appear to play an important role in the CB MNC response to NIMAs, possibly due to the induction of IL-10 and TGF-β1. We hope that our work can provide some evidence of the beneficial effect of NIMAs.

The imbalance of Th17/Treg axis involved in the pathogenesis of preeclampsia

PROBLEM

Inappropriate activation of the immune system, particularly the imbalance of T-helper type 17 (Th17)/regulatory T (Treg) cells is thought to play considerable roles in preeclampsia (PE). To investigate the probable effects of the adaptive immune system in the pathophysiology of PE, we analyzed the dynamic changes of Th17/Treg cells, cytokines profile, and transcription pattern of Th17/Treg-related genes and microRNAs (miRNAs) in 50 women suffering from PE in comparison with 50 healthy pregnant women.

METHODS

Expressions of cytokines, specific transcription factors, and related miRNAs were measured by real-time polymerase chain reaction (PCR). Enzyme-linked immunosorbent assay (ELISA) was used to test the interleukin (IL)-17, IL-23, IL-6, and IL-10 and transforming growth factor β in serum and supernatant of peripheral blood mononuclear cells (PBMCs). The frequency of Th17 and Treg cells were determined by flow cytometry.

RESULTS

PE patients exhibited a decreased number of Treg cells (p = 0.006), while Th17 cells were increased ( p = 0.004). Forkhead box P3 and IL-10 mRNA expressions were reduced ( p = 0.0001 and 0.0028, respectively), while expressions of retinoic acid receptor-related orphan nuclear receptor γt, IL-17, IL-23, and IL-6 were enhanced ( p < 0.0001, 0.0018, 0.0014, and 0.027, respectively). ELISA results also showed increased levels of IL-6, IL-17, and IL-23 ( p = 0.022, 0.0005, 0.0081, respectively), and decreased levels of IL-10 in the supernatant of PBMCs of PE patients compared with control group ( p = 0.0011). There was significant upregulation of miR-106b and miR-326 ( p = 0.0048 and 0.028, respectively) in PE patients in comparison with the control group.

CONCLUSIONS

These findings suggest that imbalance of Th17/Treg cells, regulated possibly via microRNAs, may be involved in the pathogenesis of PE, emphasizing on the importance of these cells in feto-maternal immune cross-talk.

Reevaluation of Pluripotent Cytokine TGF-β3 in Immunity

Transforming growth factor (TGF)-βs are pluripotent cytokines with stimulatory and inhibitory properties for multiple types of immune cells. Analyses of genetic knockouts of each isoform of TGF-β have revealed differing expression patterns and distinct roles for the three mammalian isoforms of TGF-β. Considerable effort has been focused on understanding the molecular mechanisms of TGF-β1-mediated immune regulation, given its pivotal role in prohibiting systemic autoimmune disease. In recent years, functional similarities and differences between the TGF-β isoforms have delineated their distinct roles in the development of immunopathology and immune tolerance, with increased recent attention being focused on TGF-β3. In addition to the characteristic properties of each TGF-β isoform, recent progress has identified determinants of context-dependent functionality, including various cellular targets, cytokine concentrations, tissue microenvironments, and cytokine synergy, which combine to shape the physiological and pathophysiological roles of the TGF-βs in immunity. Controlling TGF-β production and signaling is being tested as a novel therapeutic strategy in multiple clinical trials for several human diseases. This review highlights advances in the understanding of the cellular sources, activation processes, contextual determinants, and immunological roles of TGF-β3 with comparisons to other TGF-β isoforms.

Expanded Regulatory T Cells Induce Alternatively Activated Monocytes With a Reduced Capacity to Expand T Helper-17 Cells

Regulatory T cells (Tregs) are essential in maintaining peripheral immunological tolerance by modulating several subsets of the immune system including monocytes. Under inflammatory conditions, monocytes migrate into the tissues, where they differentiate into dendritic cells or tissue-resident macrophages. As a result of their context-dependent plasticity, monocytes have been implicated in the development/progression of graft-vs-host disease (GvHD), autoimmune diseases and allograft rejection. In the last decade, Tregs have been exploited for their use in cell therapy with the aim to induce tolerance after solid organ transplantation and for the treatment of autoimmune diseases and GvHD. To date, safety and feasibility of Treg infusion has been demonstrated; however, many questions of how these cells induce tolerance have been raised and need to be answered. As monocytes constitute the major cellular component in inflamed tissues, we have developed an in vitro model to test how Tregs modulate their phenotype and function. We demonstrated that expanded Tregs can drive monocytes toward an alternatively activated state more efficiently than freshly isolated Tregs. The effect of expanded Tregs on monocytes led to a reduced production of pro-inflammatory cytokines (IL-6 and tumor necrosis factor-α) and NF-κB activation. Furthermore, monocytes co-cultured with expanded Tregs downregulated the expression of co-stimulatory and MHC-class II molecules with a concomitant upregulation of M2 macrophage specific markers, CD206, heme oxygenase-1, and increased interleukin-10 production. Importantly, monocytes co-cultured with expanded Tregs showed a reduced capacity to expand IL-17-producing T cells compared with monocyte cultured with freshly isolated Tregs and conventional T cells. The capacity to decrease the expansion of pro-inflammatory Th-17 was not cytokine mediated but the consequence of their lower expression of the co-stimulatory molecule CD86. Our data suggest that expanded Tregs have the capacity to induce phenotypical and functional changes in monocytes that might be crucial for tolerance induction in transplantation and the prevention/treatment of GvHD and autoimmune diseases.

Knockdown of Smad7 With a Specific Antisense Oligonucleotide Attenuates Colitis and Colitis-Driven Colonic Fibrosis in Mice

BACKGROUND

In Crohn's disease (CD), the pathogenic immune response is associated with high Smad7, an inhibitor of TGF-β1 signaling. Smad7 knockdown with Mongersen, a specific antisense oligonucleotide-containing compound, restores TGF-β1 activity leading to inhibition of inflammatory signals and associates with clinical benefit in CD patients. As TGF-β1 is pro-fibrogenic, it remains unclear whether Mongersen-induced Smad7 inhibition increases the risk of intestinal fibrosis. We assessed the impact of Smad7 inhibition on the course of colitis-driven intestinal fibrosis in mice.

METHODS

BALB/c mice were rectally treated with increasing doses of trinitrobenzene sulfonic acid (TNBS) for 8 or 12 weeks. The effect of oral Smad7 antisense or control oligonucleotide, administered to mice starting from week 5 or week 8, respectively, on mucosal inflammation and colitis-associated colonic fibrosis was assessed. Mucosal samples were analyzed for Smad7 by immunoblotting and immunohistochemistry, TGF-β1 by enzyme-linked immunosorbent assay, and collagen by immunohistochemistry.

RESULTS

TNBS-induced chronic colitis was associated with colonic deposition of collagen I and fibrosis, which were evident at week 8 and became more pronounced at week 12. TNBS treatment enhanced Smad7 in both colonic epithelial and lamina propria mononuclear cells. Colitic mice treated with Smad7 antisense oligonucleotide exhibited reduced signs of colitis, less collagen deposition, and diminished fibrosis. These findings were associated with diminished synthesis of TGF-β1 and reduced p-Smad3 protein expression.

CONCLUSION

Attenuation of colitis with Smad7 antisense oligonucleotide limits development of colonic fibrosis.

TGF-β1 Signaling and Tissue Fibrosis

Activation of TGF-β1 initiates a program of temporary collagen accumulation important to wound repair in many organs. However, the outcome of temporary extracellular matrix strengthening all too frequently morphs into progressive fibrosis, contributing to morbidity and mortality worldwide. To avoid this maladaptive outcome, TGF-β1 signaling is regulated at numerous levels and intimately connected to feedback signals that limit accumulation. Here, we examine the current understanding of the core functions of TGF-β1 in promoting collagen accumulation, parallel pathways that promote physiological repair, and pathological triggers that tip the balance toward progressive fibrosis. Implicit in better understanding of these processes is the identification of therapeutic opportunities that will need to be further advanced to limit or reverse organ fibrosis.