Transcriptional and epigenetic regulation of T-helper lineage specification

Regulation of T helper cell differentiation by the interplay between histone modification and chromatin interaction

The development and function of the immune system are controlled by temporospatial gene expression programs, which are regulated by cis-regulatory elements, chromatin structure, and trans-acting factors. In this study, we cataloged the dynamic histone modifications and chromatin interactions at regulatory regions during T helper (Th) cell differentiation. Our data revealed that the H3K4me1 landscape established by MLL4 in naive CD4+ T cells is critical for restructuring the regulatory interaction network and orchestrating gene expression during the early phase of Th differentiation. GATA3 plays a crucial role in further configuring H3K4me1 modification and the chromatin interaction network during Th2 differentiation. Furthermore, we demonstrated that HSS3-anchored chromatin loops function to restrict the activity of the Th2 locus control region (LCR), thus coordinating the expression of Th2 cytokines. Our results provide insights into the mechanisms of how the interplay between histone modifications, chromatin looping, and trans-acting factors contributes to the differentiation of Th cells.

Translatomics to explore dynamic differences in immunocytes in the tumor microenvironment

Protein is an essential component of all living organisms and is primarily responsible for life activities; furthermore, its synthesis depends on a highly complex and accurate translation system. For proteins, the regulation at the translation level exceeds the sum of that during transcription, mRNA degradation, and protein degradation. Therefore, it is necessary to study regulation at the translation level. Imbalance in the translation process may change the cellular landscape, which not only leads to the occurrence, maintenance, progression, invasion, and metastasis of cancer but also affects the function of immune cells and changes the tumor microenvironment. Detailed analysis of transcriptional and protein atlases is needed to better understand how gene translation occurs. However, a more rigorous direct correlation between mRNA and protein levels is needed, which somewhat limits further studies. Translatomics is a technique for capturing and sequencing ribosome-related mRNAs that can effectively identify translation changes caused by ribosome stagnation and local translation abnormalities during cancer occurrence to further understand the changes in the translation landscape of cancer cells themselves and immune cells in the tumor microenvironment, which can provide new strategies and directions for tumor treatment.

Anti-prolactin treatment alleviates lupus conditions by regulating the JAK2-STAT3 pathway

OBJECTIVES

We previously revealed the role of prolactin (PRL) in antibody production and disease activity in patients with systemic lupus erythematosus. In this study, we sought to determine whether inhibition of PRL could improve lupus-like disease in MRL/lpr mice.

METHODS

The expression levels of PRL in various cell types of lupus patients were measured by flow cytometry. The effects of anti-PRL on animal survival, renal histopathology, creatinine, proteinuria, anti-dsDNA antibody, cytokine production, splenomegaly and lymphadenopathy were assessed. The effect of anti-PRL on the Jak2-Stat3 signalling pathway was detected by western blotting.

RESULTS

Prolactin was upregulated in B cells, neutrophils, CD4+ T cells, and monocytes isolated from patients with lupus. Furthermore, inhibition of PRL by anti-PRL treatment around the time of onset prolonged the survival of MRL/lpr mice, significantly reduced anti-dsDNA antibody production, and alleviated symptoms of lupus nephritis, splenomegaly, and lymphadenopathy. In addition, anti-PRL-treated mice showed a decrease in the levels of pathogenic cytokines such as IL-21 and IL-6. Furthermore, mechanistically, anti-PRL treatment significantly reduced the levels of p-Jak2 and p-Stat3 in MRL/lpr mice.

CONCLUSIONS

In summary, these data suggest that PRL inhibition alleviates lupus-like disease in MRL/lpr mice by modulating the Jak2-Stat3 signalling cascade. More importantly, our results imply the potential of PRL inhibitors and may provide a novel therapeutic approach for lupus.

Negative impact of Interleukin-9 on synovial regulatory T cells in rheumatoid arthritis

In Rheumatoid Arthritis (RA), regulatory T cells (Tregs) have been found to be enriched in the synovial fluid. Despite their accumulation, they are unable to suppress synovial inflammation. Recently, we showed the synovial enrichment of interleukin-9 (IL-9) producing helper T cells and its positive correlation with disease activity. Therefore, we investigated the impact of IL-9 on synovial Tregs in RA. Here, we confirmed high synovial Tregs in RA patients, however these cells were functionally impaired in terms of suppressive cytokine production (IL-10 and TGF-β). Abrogating IL-9/ IL-9 receptor interaction could restore the suppressive cytokine production of synovial Tregs and reduce the synovial inflammatory T cells producing IFN-γ, TNF-α, IL-17. However, blocking these inflammatory cytokines failed to show any effect on IL-9 producing T cells, highlighting IL-9's hierarchy in the inflammatory network. Thus, we propose that blocking IL-9 might dampen synovial inflammation by restoring Tregs function and inhibiting inflammatory T cells.

Silicon-Based Biomaterials Modulate the Adaptive Immune Response of T Lymphocytes to Promote Osteogenesis/Angiogenesis via Epigenetic Regulation

Silicon (Si)-based biomaterials are widely applied for bone regeneration. However, the underlying mechanisms of the materials function remain largely unknown. T lymphocyte-mediated adaptive immune response plays a vital role in the process of bone regeneration. In the current study, mesoporous silica (MS) is used as a model material of Si-based biomaterials. It shows that the supernatant of CD4+ T lymphocytes pretreated with MS extract significantly promotes the vascularized bone regeneration. The potential mechanism is closely related to the fact that MS extract can reduce the expression of regulatory factor X-1 (RFX-1) in CD4+ T lymphocytes. This may result in the overexpression of interleukin-17A (IL-17A) by boosting histone H3 acetylation and lowering DNA methylation and H3K9 trimethylation. Importantly, the in vivo experiments further reveal that MS particles significantly enhance bone regeneration with improved angiogenesis in the critical-sized calvarial defect mouse model accompanied by upregulation of IL-17A in peripheral blood and the proportion of Th17 cells. This study suggests that modulation of the adaptive immune response of T lymphocytes by silicate-based biomaterials plays an important role for bone regeneration.

A review of cytokine-based pathophysiology of Long COVID symptoms

The Long COVID/Post Acute Sequelae of COVID-19 (PASC) group includes patients with initial mild-to-moderate symptoms during the acute phase of the illness, in whom recovery is prolonged, or new symptoms are developed over months. Here, we propose a description of the pathophysiology of the Long COVID presentation based on inflammatory cytokine cascades and the p38 MAP kinase signaling pathways that regulate cytokine production. In this model, the SARS-CoV-2 viral infection is hypothesized to trigger a dysregulated peripheral immune system activation with subsequent cytokine release. Chronic low-grade inflammation leads to dysregulated brain microglia with an exaggerated release of central cytokines, producing neuroinflammation. Immunothrombosis linked to chronic inflammation with microclot formation leads to decreased tissue perfusion and ischemia. Intermittent fatigue, Post Exertional Malaise (PEM), CNS symptoms with "brain fog," arthralgias, paresthesias, dysautonomia, and GI and ophthalmic problems can consequently arise as result of the elevated peripheral and central cytokines. There are abundant similarities between symptoms in Long COVID and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). DNA polymorphisms and viral-induced epigenetic changes to cytokine gene expression may lead to chronic inflammation in Long COVID patients, predisposing some to develop autoimmunity, which may be the gateway to ME/CFS.

Itaconate ameliorates autoimmunity by modulating T cell imbalance via metabolic and epigenetic reprogramming

Dysregulation of Th17 and Treg cells contributes to the pathophysiology of many autoimmune diseases. Herein, we show that itaconate, an immunomodulatory metabolite, inhibits Th17 cell differentiation and promotes Treg cell differentiation by orchestrating metabolic and epigenetic reprogramming. Mechanistically, itaconate suppresses glycolysis and oxidative phosphorylation in Th17- and Treg-polarizing T cells. Following treatment with itaconate, the S-adenosyl-L-methionine/S-adenosylhomocysteine ratio and 2-hydroxyglutarate levels are decreased by inhibiting the synthetic enzyme activities in Th17 and Treg cells, respectively. Consequently, these metabolic changes are associated with altered chromatin accessibility of essential transcription factors and key gene expression in Th17 and Treg cell differentiation, including decreased RORγt binding at the Il17a promoter. The adoptive transfer of itaconate-treated Th17-polarizing T cells ameliorates experimental autoimmune encephalomyelitis. These results indicate that itaconate is a crucial metabolic regulator for Th17/Treg cell balance and could be a potential therapeutic agent for autoimmune diseases.

A Highly Sensitive Flow Cytometric Approach to Detect Rare Antigen-Specific T Cells: Development and Comparison to Standard Monitoring Tools

Personalized vaccines against patient-unique tumor-associated antigens represent a promising new approach for cancer immunotherapy. Vaccine efficacy is assessed by quantification of changes in the frequency and/or the activity of antigen-specific T cells. Enzyme-linked immunosorbent spot (ELISpot) and flow cytometry (FCM) are methodologies frequently used for assessing vaccine efficacy. We tested these methodologies and found that both ELISpot and standard FCM [monitoring CD3/CD4/CD8/IFNγ/Viability+CD14+CD19 (dump)] demonstrate background IFNγ secretion, which, in many cases, was higher than the antigen-specific signal measured by the respective methodology (frequently ranging around 0.05-0.2%). To detect such weak T-cell responses, we developed an FCM panel that included two early activation markers, 4-1BB (CD137) and CD40L (CD154), in addition to the above-cited markers. These two activation markers have a close to zero background expression and are rapidly upregulated following antigen-specific activation. They enabled the quantification of rare T cells responding to antigens within the assay well. Background IFNγ-positive CD4 T cell frequencies decreased to 0.019% ± 0.028% and CD8 T cells to 0.009% ± 0.013%, which are 19 and 13 times lower, respectively, than without the use of these markers. The presented methodology enables highly sensitive monitoring of T-cell responses to tumor-associated antigens in the very low, but clinically relevant, frequencies.

Epigenetic remodeling of the immune landscape in cancer: therapeutic hurdles and opportunities

The tumor immune microenvironment represents a sophisticated ecosystem where various immune cell subtypes communicate with cancer cells and stromal cells. The dynamic cellular composition and functional characteristics of the immune landscape along the trajectory of cancer development greatly impact the therapeutic efficacy and clinical outcome in patients receiving systemic antitumor therapy. Mounting evidence has suggested that epigenetic mechanisms are the underpinning of many aspects of antitumor immunity and facilitate immune state transitions during differentiation, activation, inhibition, or dysfunction. Thus, targeting epigenetic modifiers to remodel the immune microenvironment holds great potential as an integral part of anticancer regimens. In this review, we summarize the epigenetic profiles and key epigenetic modifiers in individual immune cell types that define the functional coordinates of tumor permissive and non-permissive immune landscapes. We discuss the immunomodulatory roles of current and prospective epigenetic therapeutic agents, which may open new opportunities in enhancing cancer immunotherapy or overcoming existing therapeutic challenges in the management of cancer.

Plasma Extracellular Vesicles Play a Role in Immune System Modulation in Minimal Hepatic Encephalopathy

Minimal hepatic encephalopathy (MHE) is associated with changes in the immune system including an increased pro-inflammatory environment and altered differentiation of CD4+ T lymphocytes. The mechanisms remain unknown. Changes in extracellular vesicle (EV) cargo including proteins and miRNAs could play a main role as mediators of immune system changes associated with MHE. The aim was to assess whether plasma EVs from MHE patients played a role in inducing the pro-inflammatory environment and altered differentiation of CD4+ T lymphocyte subtypes in MHE patients. We characterized the miRNA and protein cargo of plasma EVs from 50 cirrhotic patients (27 without and 23 with MHE) and 24 controls. CD4+ T cells from the controls were cultured with plasma EVs from the three groups of study, and the cytokine release and differentiation to CD4+ T-cell subtypes were assessed. Plasma EVs from MHE patients had altered miRNA and protein contents, and were enriched in inflammatory factors compared to the controls and patients without MHE. EVs from MHE patients modulated the expression of pro-inflammatory IL-17, IL-21, and TNF-α and anti-inflammatory TGF-β in cultured CD4+ T lymphocytes, and increased the proportion of Th follicular and Treg cells and the activation of Th17 cells. In conclusion, plasma EVs could play an important role in the induction of immune changes observed in MHE.

Host immune response against DENV and ZIKV infections

Dengue is a major public health concern, affecting almost 400 million people worldwide, with about 70% of the global burden of disease in Asia. Despite revised clinical classifications of dengue infections by the World Health Organization, the wide spectrum of the manifestations of dengue illness continues to pose challenges in diagnosis and patient management for clinicians. When the Zika epidemic spread through the American continent and then later to Africa and Asia in 2015, researchers compared the characteristics of the Zika infection to Dengue, considering both these viruses were transmitted primarily through the same vector, the Aedes aegypti female mosquitoes. An important difference to note, however, was that the Zika epidemic diffused in a shorter time span compared to the persisting feature of Dengue infections, which is endemic in many Asian countries. As the pathogenesis of viral illnesses is affected by host immune responses, various immune modulators have been proposed as biomarkers to predict the risk of the disease progression to a severe form, at a much earlier stage of the illness. However, the findings for most biomarkers are highly discrepant between studies. Meanwhile, the cross-reactivity of CD8+ and CD4+ T cells response to Dengue and Zika viruses provide important clues for further development of potential treatments. This review discusses similarities between Dengue and Zika infections, comparing their disease transmissions and vectors involved, and both the innate and adaptive immune responses in these infections. Consideration of the genetic identity of both the Dengue and Zika flaviviruses as well as the cross-reactivity of relevant T cells along with the actions of CD4+ cytotoxic cells in these infections are also presented. Finally, a summary of the immune biomarkers that have been reported for dengue and Zika viral infections are discussed which may be useful indicators for future anti-viral targets or predictors for disease severity. Together, this information appraises the current understanding of both Zika and Dengue infections, providing insights for future vaccine design approaches against both viruses.

Epigenetic regulation of immune function in asthma

Asthma is a common complex respiratory disease characterized by chronic airway inflammation and partially reversible airflow obstruction resulting from genetic and environmental determinants. Because epigenetic marks influence gene expression and can be modified by both environmental exposures and genetic variation, they are increasingly recognized as relevant to the pathogenesis of asthma and may be a key link between environmental exposures and asthma susceptibility. Unlike changes to DNA sequence, epigenetic signatures are dynamic and reversible, creating an opportunity for not only therapeutic targets but may serve as biomarkers to follow disease course and identify molecular subtypes in heterogeneous diseases such as asthma. In this review, we will examine the relationship between asthma and 3 key epigenetic processes that modify gene expression: DNA methylation, modification of histone tails, and noncoding RNAs. In addition to presenting a comprehensive assessment of the existing epigenetic studies focusing on immune regulation in asthma, we will discuss future directions for epigenetic investigation in allergic airway disease.

Inhibition of MAT2A-Related Methionine Metabolism Enhances The Efficacy of Cisplatin on Cisplatin-Resistant Cells in Lung Cancer

Objective

Tumor drug resistance is a vital obstacle to chemotherapy in lung cancer. Methionine adenosyltransferase 2A has been considered as a potential target for lung cancer treatment because targeting it can disrupt the tumorigenicity of lung tumor-initiating cells. In this study, we primarily observed the role of methionine metabolism in cisplatin-resistant lung cancer cells and the functional mechanism of MAT2A related to cisplatin resistance.

Materials and Methods

In this experimental study, we assessed the half maximal inhibitory concentration (IC₅₀) of cisplatin in different cell lines and cell viability via Cell Counting Kit-8. Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the expression of relative proteins and genes. Crystal violet staining was used to investigate cell proliferation. Additionally, we explored the transcriptional changes in lung cancer cells via RNA-seq.

Results

We found H460/DDP and PC-9 cells were more resistant to cisplatin than H460, and MAT2A was overexpressed in cisplatin-resistant cells. Interestingly, methionine deficiency enhanced the inhibitory effect of cisplatin on cell activity and the pro-apoptotic effect. Targeting MAT2A not only restrained cell viability and proliferation, but also contributed to sensitivity of H460/DDP to cisplatin. Furthermore, 4283 up-regulated and 5841 down-regulated genes were detected in H460/DDP compared with H460, and 71 signal pathways were significantly enriched. After treating H460/DDP cells with PF9366, 326 genes were up-regulated, 1093 genes were down-regulated, and 13 signaling pathways were significantly enriched. In TNF signaling pathway, CAS7 and CAS8 were decreased in H460/DDP cells, which increased by PF9366 treatment. Finally, the global histone methylation (H3K4me3, H3K9me2, H3K27me3, H3K36me3) was reduced under methionine deficiency conditions, while H3K9me2 and H3K36me3 were decreased specially via PF9366.

Conclusion

Methionine deficiency or MAT2A inhibition may modulate genes expression associated with apoptosis, DNA repair and TNF signaling pathways by regulating histone methylation, thus promoting the sensitivity of lung cancer cells to cisplatin.

Physical Activity and Systemic Lupus Erythematosus Among European Populations: A Two-Sample Mendelian Randomization Study

Background: The causal relationship between physical activity (PA) and systemic lupus erythematosus (SLE) remains uncertain. We aimed to assess the causal effect of PA on SLE by two-sample Mendelian randomization (MR) study.

Methods: Summary statistics of SLE were obtained from a genome-wide association study (GWAS) meta-analysis of European descent, including 4,036 cases and 6,959 controls. Genetic instruments for PA, including MVPA, VPA, SSOE, and average acceleration, were identified from a large-scale GWAS meta-analysis among 377,234 individuals of European ancestry from United Kingdom biobank and Atherosclerosis Risk in Communities (ARIC) study, and another GWAS with 91,105 European participants was employed for sedentary behavior. The two-sample MR study was conducted to estimate causal relationship between PA and SLE, with the inverse-variance weighted (IVW) method, simple- and weighted-median method. Moreover, MR-Egger regression, MR-PRESSO and leave-one-out analysis were performed to evaluate the potential pleiotropy effect.

Results: In the end, we totally selected 37 SNPs (15 SNPs for MVPA, 5 SNPs for VPA, 9 SNPs for SSOE, 5 SNPs for average acceleration and 3 SNPs for sedentary behavior). According to the IVW results, as the primary method, we found that genetically predicted PA was not causally associated with risk of SLE (MVPA: OR 0.44, 95% CI 0.09–2.10, p = 0.305; VPA: OR 0.20, 95% CI 0.00–18.97, p = 0.490; SSOE: OR 0.96, 95% CI 0.03–29.24, p = 0.983; average acceleration: OR 0.91, 95% CI 0.79–1.05, p = 0.190; sedentary behavior: OR 1.54, 95% CI 0.35–6.81, p = 0.572). MR-Egger, MR-PRESSO, and leave-one-out analysis did not indicate horizontal pleiotropy.

Conclusions: Our MR study suggested that genetically predicted PA was not causally associated with SLE among the European populations.

Senescence-induced changes in CD4 T cell differentiation can be alleviated by treatment with senolytics

Aging and senescence impact CD4 T helper cell (Th) subset differentiation during influenza infection. In the lungs of infected aged mice, there were significantly greater percentages of Th cells expressing the transcription factor FoxP3, indicative of regulatory CD4 T cells (Treg), when compared to young. TGF‐beta levels, which drive FoxP3 expression, were also higher in the bronchoalveolar lavage of aged mice and blocking TGF‐beta reduced the percentage of FoxP3⁺ Th in aged lungs during influenza infection. Since TGF‐beta can be the product of senescent cells, these were targeted by treatment with senolytic drugs. Treatment of aged mice with senolytics prior to influenza infection restored the differentiation of Th cells in those aged mice to a more youthful phenotype with fewer Th cells expressing FoxP3. In addition, treatment with senolytic drugs induced differentiation of aged Th toward a healing Type 2 phenotype, which promotes a return to homeostasis. These results suggest that senescent cells, via production of cytokines such as TGF‐beta, have a significant impact on Th differentiation.

L-type amino acid transporter 1 as a target for inflammatory disease and cancer immunotherapy

Ingestion of amino acids is fundamental for cellular activity. Amino acids are important components for protein synthesis but are also crucial for intracellular metabolic reactions and signal transduction. Following activation, immune cells induce metabolic reprogramming to generate adequate energy and constitutive substances. Hence, the delivery of amino acids by transporters is necessary for the progression of metabolic rewiring. In this review, we discuss how amino acids and their transporters regulate immune cell functions, with emphasis on LAT1, a transporter of large neutral amino acids. Furthermore, we explore the possibility of targeting amino acid transporters to improve immune disorders and cancer immune therapies.

Tbx21 and Foxp3 Are Epigenetically Stabilized in T-Bet+ Tregs That Transiently Accumulate in Influenza A Virus-Infected Lungs

During influenza A virus (IAV) infections, CD4⁺ T cell responses within infected lungs mainly involve T helper 1 (Th1) and regulatory T cells (Tregs). Th1-mediated responses favor the co-expression of T-box transcription factor 21 (T-bet) in Foxp3⁺ Tregs, enabling the efficient Treg control of Th1 responses in infected tissues. So far, the exact accumulation kinetics of T cell subsets in the lungs and lung-draining lymph nodes (dLN) of IAV-infected mice is incompletely understood, and the epigenetic signature of Tregs accumulating in infected lungs has not been investigated. Here, we report that the total T cell and the two-step Treg accumulation in IAV-infected lungs is transient, whereas the change in the ratio of CD4⁺ to CD8⁺ T cells is more durable. Within lungs, the frequency of Tregs co-expressing T-bet is steadily, yet transiently, increasing with a peak at Day 7 post-infection. Interestingly, T-bet⁺ Tregs accumulating in IAV-infected lungs displayed a strongly demethylated Tbx21 locus, similarly as in T-bet⁺ conventional T cells, and a fully demethylated Treg-specific demethylated region (TSDR) within the Foxp3 locus. In summary, our data suggest that T-bet⁺ but not T-bet^- Tregs are epigenetically stabilized during IAV-induced infection in the lung.

Th17 Cells in Viral Infections-Friend or Foe?

Th17 cells are recognized as indispensable in inducing protective immunity against bacteria and fungi, as they promote the integrity of mucosal epithelial barriers. It is believed that Th17 cells also play a central role in the induction of autoimmune diseases. Recent advances have evaluated Th17 effector functions during viral infections, including their critical role in the production and induction of pro-inflammatory cytokines and in the recruitment and activation of other immune cells. Thus, Th17 is involved in the induction both of pathogenicity and immunoprotective mechanisms seen in the host's immune response against viruses. However, certain Th17 cells can also modulate immune responses, since they can secrete immunosuppressive factors, such as IL-10; these cells are called non-pathogenic Th17 cells. Here, we present a brief review of Th17 cells and highlight their involvement in some virus infections. We cover these notions by highlighting the role of Th17 cells in regulating the protective and pathogenic immune response in the context of viral infections. In addition, we will be describing myocarditis and multiple sclerosis as examples of immune diseases triggered by viral infections, in which we will discuss further the roles of Th17 cells in the induction of tissue damage.

Role of Epigenetic Regulation in Plasticity of Tumor Immune Microenvironment

The tumor immune microenvironment (TIME), an immunosuppressive niche, plays a pivotal role in contributing to the development, progression, and immune escape of various types of cancer. Compelling evidence highlights the feasibility of cancer therapy targeting the plasticity of TIME as a strategy to retrain the immunosuppressive immune cells, including innate immune cells and T cells. Epigenetic alterations, such as DNA methylation, histone post-translational modifications, and noncoding RNA-mediated regulation, regulate the expression of many human genes and have been reported to be accurate in the reprogramming of TIME according to vast majority of published results. Recently, mounting evidence has shown that the gut microbiome can also influence the colorectal cancer and even extraintestinal tumors via metabolites or microbiota-derived molecules. A tumor is a kind of heterogeneous disease with specificity in time and space, which is not only dependent on genetic regulation, but also regulated by epigenetics. This review summarizes the reprogramming of immune cells by epigenetic modifications in TIME and surveys the recent progress in epigenetic-based cancer clinical therapeutic approaches. We also discuss the ongoing studies and future areas of research that benefits to cancer eradication.

Low-Dose Decitabine Augments the Activation and Anti-Tumor Immune Response of IFN-γ+ CD4+ T Cells Through Enhancing IκBα Degradation and NF-κB Activation

Background

CD4⁺ T cells play multiple roles in controlling tumor growth and increasing IFN-γ⁺ T-helper 1 cell population could promote cell-mediated anti-tumor immune response. We have previously showed that low-dose DNA demethylating agent decitabine therapy promotes CD3⁺ T-cell proliferation and cytotoxicity; however, direct regulation of purified CD4⁺ T cells and the underlying mechanisms remain unclear.

Methods

The effects of low-dose decitabine on sorted CD4⁺ T cells were detected both in vitro and in vivo. The activation, proliferation, intracellular cytokine production and cytolysis activity of CD4⁺ T cells were analyzed by FACS and DELFIA time-resolved fluorescence assays. In vivo ubiquitination assay was performed to assess protein degradation. Moreover, phosphor-p65 and IκBα levels were detected in sorted CD4⁺ T cells from solid tumor patients with decitabine-based therapy.

Results

Low-dose decitabine treatment promoted the proliferation and activation of sorted CD4⁺ T cells, with increased frequency of IFN-γ⁺ Th1 subset and enhanced cytolytic activity in vitro and in vivo. NF-κB inhibitor, BAY 11-7082, suppressed decitabine-induced CD4⁺ T cell proliferation and IFN-γ production. In terms of mechanism, low-dose decitabine augmented the expression of E3 ligase β-TrCP, promoted the ubiquitination and degradation of IκBα and resulted in NF-κB activation. Notably, we observed that in vitro low-dose decitabine treatment induced NF-κB activation in CD4⁺ T cells from patients with a response to decitabine-primed chemotherapy rather than those without a response.

Conclusion

These data suggest that low-dose decitabine potentiates CD4⁺ T cell anti-tumor immunity through enhancing IκBα degradation and therefore NF-κB activation and IFN-γ production.

Age-Dependent Differences in T-Cell Responses to Influenza A Virus

Respiratory infections from influenza A virus (IAV) cause substantial morbidity and mortality in children relative to adults. T cells play a critical role in the host response to IAV by supporting the innate and humoral responses, mediating cytotoxic activity, and promoting recovery. There are age-dependent differences in the number, subsets, and localization of T cells, which impact the host response to pathogens. In this article, we first review how T cells recognize IAV and examine differences in the resting T-cell populations between juveniles and adults. Next, we describe how the juvenile CD4⁺, CD8⁺, and regulatory T-cell responses compare with those in adults and discuss the potential physiologic and clinical consequences of the differences. Finally, we explore the roles of two unconventional T-cell types in the juvenile response to influenza, natural-killer T cells and γδ T cells. A clear understanding of age-dependent differences in the T-cell response is essential to developing therapies to prevent or reverse the deleterious effects of IAV in children.

Egr2 regulation in T cells is mediated through IFNγ/STAT1 and IL-6/STAT3 signalling pathway

The immune system is a host defence system to protect the body against foreign invaders. T cells are one of the major components of the immune cells and they are essential for immune responses. Early growth response gene (Egr2) in T cells is important for maintaining immune functions of T cells by promoting adaptive immune responses while controlling inflammation and preventing the development of autoimmune diseases. A study by our group demonstrated the function of Egr2 as a checkpoint regulator controlling the proliferation and differentiation of the T cells. In association, Egr2 and 3 play indispensable role in T cell immune response, but the mechanism regulating Egr2 expression in T cells is still unclear. In this study, we analysed the Egr2 expression mechanism in CD4 T cells under antigen stimulation. We found that Egr2 expression is regulated by different cytokines including IL-2 and IL-4, which increased Egr2 induction in activated T cells. However, inflammatory cytokines, including INFγ and IL-6, suppressed Egr2 expression through STAT1 and STAT3 signalling pathway respectively, highlighting a mechanism for tolergenic immune response on T cells.

The Impact of Milk and Its Components on Epigenetic Programming of Immune Function in Early Life and Beyond: Implications for Allergy and Asthma

Specific and adequate nutrition during pregnancy and early life is an important factor in avoiding non-communicable diseases such as obesity, type 2 diabetes, cardiovascular disease, cancers, and chronic allergic diseases. Although epidemiologic and experimental studies have shown that nutrition is important at all stages of life, it is especially important in prenatal and the first few years of life. During the last decade, there has been a growing interest in the potential role of epigenetic mechanisms in the increasing health problems associated with allergic disease. Epigenetics involves several mechanisms including DNA methylation, histone modifications, and microRNAs which can modify the expression of genes. In this study, we focus on the effects of maternal nutrition during pregnancy, the effects of the bioactive components in human and bovine milk, and the environmental factors that can affect early life (i.e., farming, milk processing, and bacterial exposure), and which contribute to the epigenetic mechanisms underlying the persistent programming of immune functions and allergic diseases. This knowledge will help to improve approaches to nutrition in early life and help prevent allergies in the future.

The expression analyses of RMRP, DDX5, and RORC in RRMS patients treated with different drugs versus naïve patients and healthy controls

Although T helper 17 (Th17) lymphocytes protect mucosal barriers against infections, they have been implicated in the development of multiple sclerosis (MS). RORC and DDX5 can regulate Th17 differentiation and the development of MS. Since RMRP, as a long non-coding RNA (lncRNA), can mediate the RORC-DDX5 complex, this lncRNA can be involved in developing MS. This study investigated the expression levels of RORC, DDX5, and RMRP in treatment-naïve relapsing-remitting multiple sclerosis (RRMS) patients, healthy controls, and RRMS patients treated with IFNβ-1α or fingolimod, or dimethyl fumarate (DMF), or glatiramer acetate (GA). There was substantial up-regulation in the expression of RORC, DDX5, and RMRP in treatment-naïve RRMS patients compared to healthy controls. Among the comparisons of their expressions in the different groups of treated patients with treatment-naïve patients, only the down-regulation of the RMRP expression level was significant in IFNβ-1α-treated patients. Also, these changes were more pronounced in female patient groups. Our analyses have highlighted the high diagnostic value of RORC, DDX5, and RMRP in treatment-naïve RRMS patients. Furthermore, RMRP has demonstrated moderate positive correlations with the expression of DDX5 and RORC in treated RRMS patients.

Immune and microRNA responses to Helicobacter muridarum infection and indole-3-carbinol during colitis

BACKGROUND

Indole-3-carbinol (I3C) and other aryl hydrocarbon receptor agonists are known to modulate the immune system and ameliorate various inflammatory and autoimmune diseases in animal models, including colitis induced by dextran sulfate sodium (DSS). MicroRNAs (miRNAs) are also gaining traction as potential therapeutic agents or diagnostic elements. Enterohepatic Helicobacter (EHH) species are associated with an increased risk of inflammatory bowel disease, but little is known about how these species affect the immune system or response to treatment.

AIM

To determine whether infection with an EHH species alters the response to I3C and how the immune and miRNA responses of an EHH species compare with responses to DSS and inflammatory bowel disease.

METHODS

We infected C57BL/6 mice with Helicobacter muridarum (H. muridarum), with and without DSS and I3C treatment. Pathological responses were evaluated by histological examination, symptom scores, and cytokine responses. MiRNAs analysis was performed on mesenteric lymph nodes to further evaluate the regional immune response.

RESULTS

H. muridarum infection alone caused colonic inflammation and upregulated proinflammatory, macrophage-associated cytokines in the colon similar to changes seen in DSS-treated mice. Further upregulation occurred upon treatment with DSS. H. muridarum infection caused broad changes in mesenteric lymph node miRNA expression, but colitis-associated miRNAs were regulated similarly in H. muridarum-infected and uninfected, DSS-treated mice. In spite of causing colitis exacerbation, H. muridarum infection did not prevent disease amelioration by I3C. I3C normalized both macrophage- and T cell-associated cytokines.

CONCLUSION

Thus, I3C may be useful for inflammatory bowel disease patients regardless of EHH infection. The miRNA changes associated with I3C treatment are likely the result of, rather than the cause of immune response changes.

Helios enhances the preferential differentiation of human fetal CD4+ naïve T cells into regulatory T cells

T cell receptor (TCR) stimulation and cytokine cues drive the differentiation of CD4⁺ naïve T cells into effector T cell populations with distinct proinflammatory or regulatory functions. Unlike adult naïve T cells, human fetal naïve CD4⁺ T cells preferentially differentiate into FOXP3⁺ regulatory T (T_reg) cells upon TCR activation independent of exogenous cytokine signaling. This cell-intrinsic predisposition for T_reg differentiation is implicated in the generation of tolerance in utero; however, the underlying mechanisms remain largely unknown. Here, we identify epigenetic and transcriptional programs shared between fetal naïve T and committed T_reg cells that are inactive in adult naïve T cells and show that fetal-derived induced T_reg (iT_reg) cells retain this transcriptional program. We show that a subset of T_reg-specific enhancers is accessible in fetal naïve T cells, including two active superenhancers at Helios Helios is expressed in fetal naïve T cells but not in adult naïve T cells, and fetal iT_reg cells maintain Helios expression. CRISPR-Cas9 ablation of Helios in fetal naïve T cells impaired their differentiation into iT_reg cells upon TCR stimulation, reduced expression of immunosuppressive genes in fetal iT_reg cells such as IL10, and increased expression of proinflammatory genes including IFNG Consequently, Helios knockout fetal iT_reg cells had reduced IL-10 and increased IFN-γ cytokine production. Together, our results reveal important roles for Helios in enhancing preferential fetal T_reg differentiation and fine-tuning eventual T_reg function. The T_reg-biased programs identified within fetal naïve T cells could potentially be used to engineer enhanced iT_reg populations for adoptive cellular therapies.

Metabolic Reprogramming in Immune Response and Tissue Inflammation

Innate and adaptive immunity participate in and regulate numerous human diseases. Increasing evidence implies that metabolic reprogramming mediates immune cell functional changes during immune responses. In this review, we present and discuss our current understanding of metabolic regulation in different immune cells and their subsets in response to pathological stimuli. An interactive biochemical and molecular model was established to characterize metabolic reprogramming and their functional implication in anti-inflammatory, immune resolution, and proinflammatory responses. We summarize 2 major features of metabolic reprogramming in inflammatory stages in innate and adaptive immune cells: (1) energy production and biosynthesis reprogramming, including increased glycolysis and decreased oxidative phosphorylation, to secure faster ATP production and biosynthesis for defense response and damage repair and (2) epigenetic reprogramming, including enhanced histone acetylation and suppressed DNA methylation, due to altered accessibility of acetyl/methyl group donor and metabolite-modulated enzymatic activity. Finally, we discuss current strategies of metabolic and epigenetic therapy in cardiovascular disease and recommend cell-specific metabolic and gene-targeted site-specific epigenetic alterations for future therapies.

The multifaceted functional role of DNA methylation in immune-mediated rheumatic diseases

Genomic predisposition cannot explain the onset of complex diseases, as well illustrated by the largely incomplete concordance among monozygotic twins. Epigenetic mechanisms, including DNA methylation, chromatin remodelling and non-coding RNA, are considered to be the link between environmental stimuli and disease onset on a permissive genetic background in autoimmune and chronic inflammatory diseases. The paradigmatic cases of rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), Sjogren's syndrome (SjS) and type-1 diabetes (T1D) share the loss of immunological tolerance to self-antigen influenced by several factors, with a largely incomplete role of individual genomic susceptibility. The most widely investigated epigenetic mechanism is DNA methylation which is associated with gene silencing and is due to the binding of methyl-CpG binding domain (MBD)-containing proteins, such as MECP2, to 5-methylcytosine (5mC). Indeed, a causal relationship occurs between DNA methylation and transcription factors occupancy and recruitment at specific genomic locus. In most cases, the results obtained in different studies are controversial in terms of DNA methylation comparison while fascinating evidence comes from the comparison of the epigenome in clinically discordant monozygotic twins. In this manuscript, we will review the mechanisms of epigenetics and DNA methylation changes in specific immune-mediated rheumatic diseases to highlight remaining unmet needs and to identify possible shared mechanisms beyond different tissue involvements with common therapeutic opportunities. Key Points • DNA methylation has a crucial role in regulating and tuning the immune system. • Evidences suggest that dysregulation of DNA methylation is pivotal in the context of immune-mediated rheumatic diseases. • DNA methylation dysregulation in FOXP3 and interferons-related genes is shared within several autoimmune diseases. • DNA methylation is an attractive marker for diagnosis and therapy.

Potential T Cell-Intrinsic Regulatory Roles for IRF5 via Cytokine Modulation in T Helper Subset Differentiation and Function

Interferon Regulatory Factor 5 (IRF5) is one of nine members of the IRF family of transcription factors. Although initially discovered as a key regulator of the type I interferon and pro-inflammatory cytokine arm of the innate immune response, IRF5 has now been found to also mediate pathways involved in cell growth and differentiation, apoptosis, metabolic homeostasis and tumor suppression. Hyperactivation of IRF5 has been implicated in numerous autoimmune diseases, chief among them systemic lupus erythematosus (SLE). SLE is a heterogeneous autoimmune disease in which patients often share similar characteristics in terms of autoantibody production and strong genetic risk factors, yet also possess unique disease signatures. IRF5 pathogenic alleles contribute one of the strongest risk factors for SLE disease development. Multiple models of murine lupus have shown that loss of Irf5 is protective against disease development. In an attempt to elucidate the regulatory role(s) of IRF5 in driving SLE pathogenesis, labs have begun to examine the function of IRF5 in several immune cell types, including B cells, macrophages, and dendritic cells. A somewhat untouched area of research on IRF5 is in T cells, even though Irf5 knockout mice were reported to have skewing of T cell subsets from T helper 1 (Th1) and T helper 17 (Th17) toward T helper 2 (Th2), indicating a potential role for IRF5 in T cell regulation. However, most studies attributed this T cell phenotype in Irf5 knockout mice to dysregulation of antigen presenting cell function rather than an intrinsic role for IRF5 in T cells. In this review, we offer a different interpretation of the literature. The role of IRF5 in T cells, specifically its control of T cell effector polarization and the resultant T cell-mediated cytokine production, has yet to be elucidated. A strong understanding of the regulatory role(s) of this key transcription factor in T cells is necessary for us to grasp the full picture of the complex pathogenesis of autoimmune diseases like SLE.

Methionine Metabolism Shapes T Helper Cell Responses through Regulation of Epigenetic Reprogramming

Epigenetic modifications on DNA and histones regulate gene expression by modulating chromatin accessibility to transcription machinery. Here we identify methionine as a key nutrient affecting epigenetic reprogramming in CD4⁺ T helper (Th) cells. Using metabolomics, we showed that methionine is rapidly taken up by activated T cells and serves as the major substrate for biosynthesis of the universal methyl donor S-adenosyl-L-methionine (SAM). Methionine was required to maintain intracellular SAM pools in T cells. Methionine restriction reduced histone H3K4 methylation (H3K4me3) at the promoter regions of key genes involved in Th17 cell proliferation and cytokine production. Applied to the mouse model of multiple sclerosis (experimental autoimmune encephalomyelitis), dietary methionine restriction reduced the expansion of pathogenic Th17 cells in vivo, leading to reduced T cell-mediated neuroinflammation and disease onset. Our data identify methionine as a key nutritional factor shaping Th cell proliferation and function in part through regulation of histone methylation.

Molecular Signatures of Dengue Virus-Specific IL-10/IFN-γ Co-producing CD4 T Cells and Their Association with Dengue Disease

Dengue virus (DENV) can cause diseases ranging from dengue fever (DF) to more severe dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). Whether antiviral T cells contribute to the protection against or pathogenesis of severe disease is not well defined. Here, we identified antigen-specific IL-10+IFN-γ+ double-positive (DP) CD4 T cells during acute DENV infection. While the transcriptomic signatures of DP cells partially overlapped with those of cytotoxic and type 1 regulatory CD4 T cells, the majority of them were non-cytotoxic/Tr1 and included IL21, IL22, CD109, and CCR1. Although we observed a higher frequency of DP cells in DHF, the transcriptomic profile of DP cells was similar in DF and DHF, suggesting that DHF is not associated with the altered phenotypic or functional attributes of DP cells. Overall, this study revealed a DENV-specific DP cell subset in patients with acute dengue disease and argues against altered DP cells as a determinant of DHF.

The emerging role of epigenetic therapeutics in immuno-oncology

The past decade has seen the emergence of immunotherapy as a prime approach to cancer treatment, revolutionizing the management of many types of cancer. Despite the promise of immunotherapy, most patients do not have a response or become resistant to treatment. Thus, identifying combinations that potentiate current immunotherapeutic approaches will be crucial. The combination of immune-checkpoint inhibition with epigenetic therapy is one such strategy that is being tested in clinical trials, encompassing a variety of cancer types. Studies have revealed key roles of epigenetic processes in regulating immune cell function and mediating antitumour immunity. These interactions make combined epigenetic therapy and immunotherapy an attractive approach to circumvent the limitations of immunotherapy alone. In this Review, we highlight the basic dynamic mechanisms underlying the synergy between immunotherapy and epigenetic therapies and detail current efforts to translate this knowledge into clinical benefit for patients.

Therapeutic effects of artesunate on lupus-prone MRL/lpr mice are dependent on T follicular helper cell differentiation and activation of JAK2-STAT3 signaling pathway

BACKGROUND

Anti-malarial drug artesunate (ART), a semi-synthetic derivative of artemisnin, has immunosuppressive effects on several autoimmune diseases, including Systemic lupus erythematosus (SLE), Rheumatoid arthritis (RA), and Colitis. However, molecular mechanisms of ART, especially on follicular helper T cells (Tfh), central players in SLE pathology, are far from clear.

PURPOSE

The object for this work is to investigate the therapeutic effect of ART on lupus-prone MRL/lpr mice and its regulatory function on Tfh cells.

STUDY DESIGN AND METHODS

MRL/lpr mice were used to explore therapeutic effects of ART on lupus-prone MRL/lpr mice and its regulatory functions on Tfh cells. Then, experiments of renal function were accomplished using the biochemical kits. Effects of ART on histopathology of kidneys, inflammatory factors and autoantibodies were examined using H&E staining, ELISA and real-time PCR. Flow cytometry and western blot analysis were used to examine effects of ART on Tfh differentiation and Jak2-Stat3 signaling pathway.

RESULTS

Upon oral administration, ART significantly prolonged the survival of MRL/lpr mice, ameliorated the lupus nephritis symptoms, decreased the levels of anti-dsDNA antibodies deposited in the kidney, and the levels of pathogenic cytokines (IL-6, IFN-γ and IL-21). After ART treatment, T-cell compartment in the spleen of MRL/lpr mice was restored in terms of reduction in the number of Tfh cells and in the maintenance of the ratio of Tfr to follicular regulatory T cells (Tfh). In addition, ART has significantly inhibited the phosphorylation levels of Jak2 and Stat3 in the MRL/lpr mice.

CONCLUSION

ART showed therapeutic effects on lupus-prone MRL/lpr mice by inhibiting the differentiation of Tfh cells as well as altering the activation status of Jak2-Stat3 signaling cascade.

Dihydrotanshinone I Alleviates Crystalline Silica-Induced Pulmonary Inflammation by Regulation of the Th Immune Response and Inhibition of STAT1/STAT3

Occupational exposure to crystalline silica (CS) results in a persistent pulmonary inflammatory response that eventually leads to abnormal tissue repair, disability, and death. The inflammatory-immune responses occur in the early stages of CS exposure, and both innate and adaptive immunity are involved. CD4+ T cells play a pivotal role in the pathogenesis of CS-induced pulmonary disease, which has no proven curative therapy. Dihydrotanshinone I (DHI), a natural product isolated from Salvia miltiorrhiza Bunge (Danshen), has anti-inflammatory and immunomodulatory properties. However, whether DHI has a protective effect on CS-induced lung disease, how it influences the Th immune response, and the potential underlying molecular mechanism(s) have not been fully clarified. In this study, DHI treatment of CS-exposed mice reduced the expression of proinflammatory cytokines and the infiltration of immune cells. It significantly ameliorated CS-induced pulmonary inflammation by attenuating T helper (Th)1 and Th17 responses, which were tightly related to the inhibition of STAT1 and STAT3. DHI significantly altered Th2 cytokines but not the Th2 nuclear transcription factor. Furthermore, our study found that DHI treatment also affected regulatory T cell activity in CS-injured mice. Taken together, our findings indicated that DHI could modulate Th responses and alleviate CS-induced pulmonary inflammation, suggesting a novel application of DHI in CS-induced pulmonary disease.

Desmoplasia in Lymph Node Metastasis of Pancreatic Adenocarcinoma Reveals Activation of Cancer-Associated Fibroblasts Pattern and T-helper 2 Immune Cell Infiltration

OBJECTIVES

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a peritumoral proliferation of fibroblasts and extracellular matrix production known as desmoplasia. We aimed to study desmoplasia in PDAC lymph node (LN) metastases.

METHODS

We evaluated LNs from 66 patients with PDAC and LN metastases. We used immunohistochemistry and real-time polymerase chain reaction to phenotype the desmoplastic response.

RESULTS

Desmoplasia was identified in 57% of patients with LN metastases (Des+). Cancer-associated fibroblasts (CAFs) in Des+ expressed α-smooth muscle actin and collagen 11A1. The latter expression was present only in CAFs but not in LN stroma or in LN metastases without desmoplasia (Des-). Desmoplasia was associated with upregulation of transforming growth factor β messenger RNA. Whereas numbers of CD8+ in tumor vicinity were not different between Des+ and Des- patients (78 [standard deviation {SD}, 57] vs 92 [SD, 52], P = 0.48, respectively), the numbers of GATA-3+ cells, a marker of T-helper 2 immune response was significantly increased (3.7 [SD, 6.3] for Des+ vs 1.3 [SD, 2.7] for Des-, P < 0.05).

CONCLUSIONS

Lymph node desmoplasia is associated with CAF pattern activation and Th2 infiltration. Therapeutic modulation of desmoplasia may be relevant in the metastatic phase and influence antitumor immune response.

The Cellular Origins of Breast Implant-Associated Anaplastic Large Cell Lymphoma (BIA-ALCL): Implications for Immunogenesis

The exact cellular origins of most malignancies are unknown, largely because of the complex nature of malignancies, and because the potential vast number of pathways towards transformation are difficult to discern from established growths. This is compounded by the fact that cancer cells have evolved rather than being the consequence of a design process, with most data collected from (sometimes epidemiological) studies of large numbers of related malignancies. In the case of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL), the relative rarity of this disease, coupled with limited insight into its biological basis, have hampered progress. The known facts that are holding up as our knowledge increases with rising incidences are that most cases have been reported in the context of textured breast implants, although not all women with these implants develop BIA-ALCL, and cure for early-stage disease (accounting for the majority of patients) can be achieved via complete capsulectomy and implant removal. However, some theories can be gleaned from the limited biological studies conducted to date whereby a T-helper cell derivation is implicated, with its specific and apparent subset of origin dependent on, and shaped by, a number of factors, including the inflammatory microenvironment (the presence of other inflammatory cell types), the driving antigen (bacterial and/or synthetic), the acquisition of driving oncogenic events, and the inherent genetics/health status of the patient.

Assessing the role of the T-box transcription factor Eomes in B cell differentiation during either Th1 or Th2 cell-biased responses

Successful T-dependent humoral responses require the production of antibody-secreting plasmablasts, as well as the formation of germinal centers which eventually form high-affinity B cell memory. The ability of B cells to differentiate into germinal center and plasma cells, as well as the ability to tailor responses to different pathogens, is driven by transcription factors. In T cells, the T-box transcription factors T-bet and Eomesodermin (Eomes) regulate effector and memory T cell differentiation, respectively. While T-bet has a critical role in regulating anti-viral B cell responses, a role for Eomes in B cells has yet to be described. We therefore investigated whether Eomes was required for B cell differentiation during either Th1 or Th2 cell-biased immune responses. Here, we demonstrate that deletion of Eomes specifically in B cells did not affect B cell differentiation in response to vaccination, as well as following viral or helminth infection. In contrast to its established role in CD8⁺ T cells, Eomes did not influence memory B cell differentiation. Finally, the use of an Eomes reporter mouse confirmed the lack of Eomes expression during immune responses. Thus, germinal center and plasma cell differentiation and the formation of isotype-switched memory B cells in response to infection are independent of Eomes expression.

A Functionally Different Immune Phenotype in Cattle Is Associated With Higher Mastitis Incidence

A novel vaccine against bovine viral diarrhea (BVD) induced pathogenic antibody production in 5-10% of BVD-vaccinated cows. Transfer of these antibodies via colostrum caused Bovine neonatal pancytopenia (BNP) in calves, with a lethality rate of 90%. The exact immunological mechanisms behind the onset of BNP are not fully understood to date. To gain further insight into these mechanisms, we analyzed the immune proteome from alloreactive antibody producers (BNP cows) and non-responders. After in vitro stimulation of peripheral blood derived lymphocytes (PBL), we detected distinctly deviant expression levels of several master regulators of immune responses in BNP cells, pointing to a changed immune phenotype with severe dysregulation of immune response in BNP cows. Interestingly, we also found this response pattern in 22% of non-BVD-vaccinated cows, indicating a genetic predisposition of this immune deviant (ID) phenotype in cattle. We additionally analyzed the functional correlation of the ID phenotype with 10 health parameters and 6 diseases in a retrospective study over 38 months. The significantly increased prevalence of mastitis among ID cows emphasizes the clinical relevance of this deviant immune response and its potential impact on the ability to fight infections.

Chromatin Accessibility and Interactions in the Transcriptional Regulation of T Cells

During T cell differentiation and activation, specific stimuli, and a network of transcription factors (TFs) are involved in orchestrating chromatin accessibility, establishing enhancer-promoter interactions, and regulating gene expression. Over the past few years, there have been new insights into how chromatin interactions coordinate differentiation during T cell development and how regulatory elements are programmed to allow T cells to differentially respond to distinct stimuli. In this review, we discuss recent advances related to the roles of TFs in establishing the regulatory chromatin landscapes that orchestrate T cell development and differentiation. In particular, we focus on the role of TFs (e.g., TCF-1, BCL11B, PU.1, STAT3, STAT5, AP-1, and IRF4) in mediating chromatin accessibility and interactions and in regulating gene expression in T cells, including gene expression that is dependent on IL-2 and IL-21. Furthermore, we discuss the state of knowledge on enhancer-promoter interactions and how autoimmune disease risk variants can be linked to molecular functions of putative target genes.

Decidualization of Human Endometrial Stromal Fibroblasts is a Multiphasic Process Involving Distinct Transcriptional Programs

Decidual stromal cells differentiate from endometrial stromal fibroblasts (ESFs) under the influence of progesterone and cyclic adenosine monophosphate (cAMP) and are essential for implantation and the maintenance of pregnancy. They evolved in the stem lineage of placental (eutherian) mammals coincidental with the evolution of implantation. Here we use the well-established in vitro decidualization protocol to compare early (3 days) and late (8 days) gene transcription patterns in immortalized human ESF. We document extensive, dynamic changes in the early and late decidual cell transcriptomes. The data suggest the existence of an early signal transducer and activator of transcription (STAT) pathway dominated state and a later nuclear factor κB (NFKB) pathway regulated state. Transcription factor expression in both phases is characterized by putative or known progesterone receptor ( PGR) target genes, suggesting that both phases are under progesterone control. Decidualization leads to proliferative quiescence, which is reversible by progesterone withdrawal after 3 days but to a lesser extent after 8 days of decidualization. In contrast, progesterone withdrawal induces cell death at comparable levels after short or long exposure to progestins and cAMP. We conclude that decidualization is characterized by a biphasic gene expression dynamic that likely corresponds to different phases in the establishment of the fetal-maternal interface.

Altered Cell-Cycle Control, Inflammation, and Adhesion in High-Risk Persistent Bronchial Dysplasia

Persistent bronchial dysplasia is associated with increased risk of developing invasive squamous cell carcinoma (SCC) of the lung. In this study, we hypothesized that differences in gene expression profiles between persistent and regressive bronchial dysplasia would identify cellular processes that underlie progression to SCC. RNA expression arrays comparing baseline biopsies from 32 bronchial sites that persisted/progressed to 31 regressive sites showed 395 differentially expressed genes [ANOVA, FDR ≤ 0.05). Thirty-one pathways showed significantly altered activity between the two groups, many of which were associated with cell-cycle control and proliferation, inflammation, or epithelial differentiation/cell-cell adhesion. Cultured persistent bronchial dysplasia cells exhibited increased expression of Polo-like kinase 1 (PLK1), which was associated with multiple cell-cycle pathways. Treatment with PLK1 inhibitor induced apoptosis and G2-M arrest and decreased proliferation compared with untreated cells; these effects were not seen in normal or regressive bronchial dysplasia cultures. Inflammatory pathway activity was decreased in persistent bronchial dysplasia, and the presence of an inflammatory infiltrate was more common in regressive bronchial dysplasia. Regressive bronchial dysplasia was also associated with trends toward overall increases in macrophages and T lymphocytes and altered polarization of these inflammatory cell subsets. Increased desmoglein 3 and plakoglobin expression was associated with higher grade and persistence of bronchial dysplasia. These results identify alterations in the persistent subset of bronchial dysplasia that are associated with high risk for progression to invasive SCC. These alterations may serve as strong markers of risk and as effective targets for lung cancer prevention.Significance: Gene expression profiling of high-risk persistent bronchial dysplasia reveals changes in cell-cycle control, inflammatory activity, and epithelial differentiation/cell-cell adhesion that may underlie progression to invasive SCC. Cancer Res; 78(17); 4971-83. ©2018 AACR.

TGF-β-mediated enhancement of TH17 cell generation is inhibited by bone morphogenetic protein receptor 1α signaling

The cytokines of the transforming growth factor-β (TGF-β) family promote the growth and differentiation of multiple tissues, but the role of only the founding member, TGF-β, in regulating the immune responses has been extensively studied. TGF-β is critical to prevent the spontaneous activation of self-reactive T cells and sustain immune homeostasis. In contrast, in the presence of proinflammatory cytokines, TGF-β promotes the differentiation of effector T helper 17 (TH17) cells. Abrogating TGF-β receptor signaling prevents the development of interleukin-17 (IL-17)-secreting cells and protects mice from TH17 cell-mediated autoimmunity. We found that the receptor of another member of TGF-β family, bone morphogenetic protein receptor 1α (BMPR1α), regulates T helper cell activation. We found that the differentiation of TH17 cells from naive CD4+ T cells was inhibited in the presence of BMPs. Abrogation of BMPR1α signaling during CD4+ T cell activation induced a developmental program that led to the generation of inflammatory effector cells expressing large amounts of IL-17, IFN-γ, and TNF family cytokines and transcription factors defining the TH17 cell lineage. We found that TGF-β and BMPs cooperated to establish effector cell functions and the cytokine profile of activated CD4+ T cells. Together, our data provide insight into the immunoregulatory function of BMPs.

miR-340 Alleviates Psoriasis in Mice through Direct Targeting of IL-17A

Th17 cell is a well-known lineage of CD4⁺ effector Th cells that selectively produce IL-17A and play critical roles during the pathogenesis of autoimmune disease. A microRNA (miRNA) is a small noncoding RNA molecule that functions in posttranscriptional regulation of gene expression. Recently, an increasing number of studies have demonstrated that multiple miRNAs are dysregulated in patients with various autoimmune diseases and mediate autoimmune disease pathologic condition at least in part through the regulation of Th17 response. However, among the few miRNAs identified so far that play possible roles in the differentiation of Th17 cells, they all regulate the Th17 response through targeting negative or positive regulators of Th17 differentiation. In the current study, we sought to identify new miRNAs that can directly regulate the expression of IL-17A, the most important cytokine produced by Th17 cells. Our results showed that the 3' untranslated region of mouse IL-17A can act as a negative regulatory element to downregulate gene expression. Further study revealed that miR-340 can specifically bind to the 3' untranslated region of mouse IL-17A and downregulate the expression of endogenous IL-17A. More importantly, we demonstrated that treatment with miR-340 alleviates the clinical severity of imiquimod-induced psoriasis in mice through the downregulation of IL-17A. These data indicate that miR-340 may be a useful therapeutic target for the treatment of psoriasis and other IL-17A-mediated autoimmune diseases.

Quantitative proteomic characterization and comparison of T helper 17 and induced regulatory T cells

The transcriptional network and protein regulators that govern T helper 17 (Th17) cell differentiation have been studied extensively using advanced genomic approaches. For a better understanding of these biological processes, we have moved a step forward, from gene- to protein-level characterization of Th17 cells. Mass spectrometry–based label-free quantitative (LFQ) proteomics analysis were made of in vitro differentiated murine Th17 and induced regulatory T (iTreg) cells. More than 4,000 proteins, covering almost all subcellular compartments, were detected. Quantitative comparison of the protein expression profiles resulted in the identification of proteins specifically expressed in the Th17 and iTreg cells. Importantly, our combined analysis of proteome and gene expression data revealed protein expression changes that were not associated with changes at the transcriptional level. Our dataset provides a valuable resource, with new insights into the proteomic characteristics of Th17 and iTreg cells, which may prove useful in developing treatment of autoimmune diseases and developing tumor immunotherapy.

T helper 17 (Th17) cells and induced regulatory T (iTreg) cells are two subsets of T helper cells differentiated from naïve cells that play important roles in autoimmune diseases, immune homeostasis, and tumor immunity. The differentiation process is achieved by changes in numerous proteins, including transcription regulators, enzymes, membrane receptors, and cytokines, which are critical in lineage commitment. To profile protein expression changes in Th17 and iTreg cells, we polarized murine naïve CD4+ T (Thp) cells in vitro to Th17 and iTreg cells and performed quantitative proteomic analysis of these cells. More than 4,000 proteins, covering almost all subcellular compartments, were detected. Quantitative comparison of the protein expression profiles resulted in the identification of proteins specifically expressed in the Th17 and iTreg cells. Importantly, our combined analysis of proteome and gene expression data revealed protein expression changes that were not associated with changes at the transcriptional level. The present study serves as a valuable resource that may prove useful in developing treatment of autoimmune diseases and cancer.

Histone modifications and their role in epigenetics of atopy and allergic diseases

This review covers basic aspects of histone modification and the role of posttranslational histone modifications in the development of allergic diseases, including the immune mechanisms underlying this development. Together with DNA methylation, histone modifications (including histone acetylation, methylation, phosphorylation, ubiquitination, etc.) represent the classical epigenetic mechanisms. However, much less attention has been given to histone modifications than to DNA methylation in the context of allergy. A systematic review of the literature was undertaken to provide an unbiased and comprehensive update on the involvement of histone modifications in allergy and the mechanisms underlying this development. In addition to covering the growing interest in the contribution of histone modifications in regulating the development of allergic diseases, this review summarizes some of the evidence supporting this contribution. There are at least two levels at which the role of histone modifications is manifested. One is the regulation of cells that contribute to the allergic inflammation (T cells and macrophages) and those that participate in airway remodeling [(myo-) fibroblasts]. The other is the direct association between histone modifications and allergic phenotypes. Inhibitors of histone-modifying enzymes may potentially be used as anti-allergic drugs. Furthermore, epigenetic patterns may provide novel tools in the diagnosis of allergic disorders.

Tailoring Immune Responses toward Autoimmunity: Transcriptional Regulators That Drive the Creation and Collusion of Autoreactive Lymphocytes

T-dependent humoral immune responses to infection involve a collaboration between B and CD4 T cell activation, migration, and co-stimulation, thereby culminating in the formation of germinal centers (GCs) and eventual differentiation into memory cells and long-lived plasma cells (PCs). CD4 T cell-derived signals drive the formation of a tailored B cell response. Downstream of these signals are transcriptional regulators that are the critical enactors of immune cell programs. In particular, a core group of transcription factors regulate both B and T cell differentiation, identity, and function. The timing and expression levels of these transcription factors are tightly controlled, with dysregulated expression correlated to immune cell dysfunction in autoimmunity and lymphomagenesis. Recent studies have significantly advanced our understanding of both extrinsic and intrinsic regulators of autoreactive B cells and antibody-secreting PCs in systemic lupus erythematosus, rheumatoid arthritis, and other autoimmune conditions. Yet, there are still gaps in our understanding of the causative role these regulators play, as well as the link between lymphoid responses and peripheral damage. This review will focus on the genesis of immunopathogenic CD4 helper and GC B cells. In particular, we will detail the transcriptional regulation of cytokine and chemokine receptor signaling during the pathogenesis of GC-derived autoimmune conditions in both murine models and human patients.

IL-6/STAT3 pathway induced deficiency of RFX1 contributes to Th17-dependent autoimmune diseases via epigenetic regulation

Epigenetic modifications affect the differentiation of T cell subsets and the pathogenesis of autoimmune diseases, but many mechanisms of epigenetic regulation of T cell differentiation are unclear. Here we show reduced expression of the transcription factor RFX1 in CD4⁺ T cells from patients with systemic lupus erythematosus, which leads to IL-17A overexpression through increased histone H3 acetylation and decreased DNA methylation and H3K9 tri-methylation. Conditional deletion of Rfx1 in mice exacerbates experimental autoimmune encephalomyelitis and pristane-induced lupus-like syndrome and increases induction of Th17 cells. In vitro, Rfx1 deficiency increases the differentiation of naive CD4⁺ T cells into Th17 cells, but this effect can be reversed by forced expression of Rfx1. Importantly, RFX1 functions downstream of STAT3 and phosphorylated STAT3 can inhibit RFX1 expression, highlighting a non-canonical pathway that regulates differentiation of Th17 cells. Collectively, our findings identify a unique role for RFX1 in Th17-related autoimmune diseases.

Th17 cells are a common pathogenic effector cell in autoimmune inflammatory diseases. Here the authors show that the transcription factor RFX1 limits Th17 differentiation and is protective against the pathogenesis of Th17-driven autoimmune diseases.