Mechanisms underlying helper T-cell plasticity: implications for immune-mediated disease

The Th1/Th2 paradigm: A misrepresentation of helper T cell plasticity

For decades, the Th1/2 paradigm has been used to classify immune responses as either Th1 or Th2-biased. However, in recent years, a staggering amount of evidence has emerged to support rejection of the classical Th1/Th2 paradigm, such as the discoveries of new helper T cell subsets, helper T cell plasticity and protective mixed-Th1/Th2 responses. This opinion piece investigates the shortcomings of classical Th1/Th2 paradigm in the context of recent works, with the goal of facilitating the development of newer models to represent the diversity of Th cells.

Understanding Autoimmunity: Mechanisms, Predisposing Factors, and Cytokine Therapies

Autoimmunity refers to an organism's immune response against its own healthy cells, tissues, or components, potentially leading to irreversible damage to vital organs. Central and peripheral tolerance mechanisms play crucial roles in preventing autoimmunity by eliminating self-reactive T and B cells. The disruption of immunological tolerance, characterized by the failure of these mechanisms, results in the aberrant activation of autoreactive lymphocytes that target self-tissues, culminating in the pathogenesis of autoimmune disorders. Genetic predispositions, environmental exposures, and immunoregulatory disturbances synergistically contribute to the susceptibility and initiation of autoimmune pathologies. Within the realm of immune therapies for autoimmune diseases, cytokine therapies have emerged as a specialized strategy, targeting cytokine-mediated regulatory pathways to rectify immunological imbalances. Proinflammatory cytokines are key players in inducing and propagating autoimmune inflammation, highlighting the potential of cytokine therapies in managing autoimmune conditions. This review discusses the etiology of autoimmune diseases, current therapeutic approaches, and prospects for future drug design.

Exploring the immune characteristions of CRKP pneumonia at single-cell level

The immune dysregulation associated with carbapenem-resistant Klebsiella pneumoniae (CRKP) severity was investigated through single-cell RNA sequencing (scRNA-seq) of 5 peripheral blood samples from 3 patients with moderate and severe CRKP pneumonia. Additionally, scRNA-seq datasets from two individuals with COVID-19 were included for comparative analysis. The dynamic characterization and functional properties of each immune cell type were examined by delineating the transcriptional profiles of immune cells throughout the transition from moderate to severe conditions. Overall, most immune cells in CRKP patients exhibited a robust interferon-α response and inflammatory reaction compared to healthy controls, mirroring observations in COVID-19 patients. Furthermore, cell signatures associated with NK cells, macrophages, and monocytes were identified in CRKP progression including PTPRCAP for NK cells, C1QB for macrophages, and S100A12 for both macrophages and monocytes. In summary, this study offers a comprehensive scRNA-seq resource for illustrating the dynamic immune response patterns during CRKP progression, thereby shedding light on the associations between CRKP and COVID-19.

The Role of Regulatory T Cells in Allergic Diseases: Collegium Internationale Allergologicum (CIA) Update 2024

BACKGROUND

Allergy represents a major health problem of increasing prevalence worldwide with a high socioeconomic impact. Our knowledge on the molecular mechanisms underlying allergic diseases and their treatments has significantly improved over the last years. The generation of allergen-specific regulatory T cells (Tregs) is crucial in the induction of healthy immune responses to allergens, preventing the development and worsening of allergic diseases.

SUMMARY

In the last decades, intensive research has focused on the study of the molecular mechanisms involved in Treg development and Treg-mediated suppression. These mechanisms are essential for the induction of sustained tolerance by allergen-specific immunotherapy (AIT) after treatment discontinuation. Compelling experimental evidence demonstrated altered suppressive capacity of Tregs in patients suffering from allergic rhinitis, allergic asthma, food allergy, or atopic dermatitis, as well as the restoration of their numbers and functionality after successful AIT.

KEY MESSAGE

The better understanding of the molecular mechanisms involved in Treg generation during allergen tolerance induction might well contribute to the development of novel strategies for the prevention and treatment of allergic diseases.

Is Th17-Targeted Therapy Effective in Systemic Lupus Erythematosus?

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with a broad spectrum of clinical manifestations. The proposed pathophysiological hypotheses of SLE are numerous, involving both innate and adaptive abnormal immune responses. SLE is characterized by the overproduction of different autoantibodies that form immune complexes, which cause damage in different organs. Current therapeutic modalities are anti-inflammatory and immunosuppressive. In the last decade, we have witnessed the development of many biologicals targeting different cytokines and other molecules. One of them is interleukin-17 (IL-17), a central cytokine of a proinflammatory process that is mediated by a group of helper T cells called Th17. Direct inhibitors of IL-17 are used in psoriatic arthritis, spondyloarthritis, and other diseases. Evidence about the therapeutic potential of Th17-targeted therapies in SLE is scarce, and probably the most promising is related to lupus nephritis. As SLE is a complex heterogeneous disease with different cytokines involved in its pathogenesis, it is highly unlikely that inhibition of only one molecule, such as IL-17, will be effective in the treatment of all clinical manifestations. Future studies should identify SLE patients that are eligible for Th17-targeted therapy.

Spatial Proteomics for the Molecular Characterization of Breast Cancer

Breast cancer (BC) is a major global health issue, affecting a significant proportion of the female population and contributing to high rates of mortality. One of the primary challenges in the treatment of BC is the disease's heterogeneity, which can lead to ineffective therapies and poor patient outcomes. Spatial proteomics, which involves the study of protein localization within cells, offers a promising approach for understanding the biological processes that contribute to cellular heterogeneity within BC tissue. To fully leverage the potential of spatial proteomics, it is critical to identify early diagnostic biomarkers and therapeutic targets, and to understand protein expression levels and modifications. The subcellular localization of proteins is a key factor in their physiological function, making the study of subcellular localization a major challenge in cell biology. Achieving high resolution at the cellular and subcellular level is essential for obtaining an accurate spatial distribution of proteins, which in turn can enable the application of proteomics in clinical research. In this review, we present a comparison of current methods of spatial proteomics in BC, including untargeted and targeted strategies. Untargeted strategies enable the detection and analysis of proteins and peptides without a predetermined molecular focus, whereas targeted strategies allow the investigation of a predefined set of proteins or peptides of interest, overcoming the limitations associated with the stochastic nature of untargeted proteomics. By directly comparing these methods, we aim to provide insights into their strengths and limitations and their potential applications in BC research.

Cancer Stem Cell Relationship with Pro-Tumoral Inflammatory Microenvironment

Inflammatory processes and cancer stem cells (CSCs) are increasingly recognized as factors in the development of tumors. Emerging evidence indicates that CSCs are associated with cancer properties such as metastasis, treatment resistance, and disease recurrence. However, the precise interaction between CSCs and the immune microenvironment remains unexplored. Although evasion of the immune system by CSCs has been extensively studied, new research demonstrates that CSCs can also control and even profit from the immune response. This review provides an overview of the reciprocal interplay between CSCs and tumor-infiltrating immune cells, collecting pertinent data about how CSCs stimulate leukocyte reprogramming, resulting in pro-tumor immune cells that promote metastasis, chemoresistance, tumorigenicity, and even a rise in the number of CSCs. Tumor-associated macrophages, neutrophils, Th17 and regulatory T cells, mesenchymal stem cells, and cancer-associated fibroblasts, as well as the signaling pathways involved in these pro-tumor activities, are among the immune cells studied. Although cytotoxic leukocytes have the potential to eliminate CSCs, immune evasion mechanisms in CSCs and their clinical implications are also known. We intended to compile experimental findings that provide direct evidence of interactions between CSCs and the immune system and CSCs and the inflammatory milieu. In addition, we aimed to summarize key concepts in order to comprehend the cross-talk between CSCs and the tumor microenvironment as a crucial process for the effective design of anti-CSC therapies.

Evolution of developmental and comparative immunology in poultry: The regulators and the regulated

Avian has a unique immune system that evolved in response to environmental pressures in all aspects of innate and adaptive immune responses, including localized and circulating lymphocytes, diversity of immunoglobulin repertoire, and various cytokines and chemokines. All of these attributes make birds an indispensable vertebrate model for studying the fundamental immunological concepts and comparative immunology. However, research on the immune system in birds lags far behind that of humans, mice, and other agricultural animal species, and limited immune tools have hindered the adequate application of birds as disease models for mammalian systems. An in-depth understanding of the avian immune system relies on the detailed studies of various regulated and regulatory mediators, such as cell surface antigens, cytokines, and chemokines. Here, we review current knowledge centered on the roles of avian cell surface antigens, cytokines, chemokines, and beyond. Moreover, we provide an update on recent progress in this rapidly developing field of study with respect to the availability of immune reagents that will facilitate the study of regulatory and regulated components of poultry immunity. The new information on avian immunity and available immune tools will benefit avian researchers and evolutionary biologists in conducting fundamental and applied research.

Positive Effects of Biologics on Osteoporosis in Rheumatoid Arthritis

Osteoporosis is a systemic skeletal disorder that causes vulnerability of bones to fracture owing to reduction in bone density and deterioration of the bone tissue microstructure. The prevalence of osteoporosis is higher in patients with autoimmune inflammatory rheumatic diseases, including rheumatoid arthritis (RA), than in those of the general population. In this autoimmune inflammatory rheumatic disease, in addition to known risk factors for osteoporosis, various factors such as chronic inflammation, autoantibodies, metabolic disorders, drugs, and decreased physical activity contribute to additional risk. In RA, disease-related inflammation plays an important role in local or systemic bone loss, and active treatment for inflammation can help prevent osteoporosis. In addition to conventional synthetic disease-modifying anti-rheumatic drugs that have been traditionally used for treatment of RA, biologic DMARDs and targeted synthetic DMARDs have been widely used. These agents can be employed more selectively and precisely based on disease pathogenesis. It has been reported that these drugs can inhibit bone loss by not only reducing inflammation in RA, but also by inhibiting bone resorption and promoting bone formation. In this review, the pathogenesis and research results of the increase in osteoporosis in RA are reviewed, and the effects of biological agents on osteoporosis are discussed.

Advances in T Cells Based on Inflammation in Metabolic Diseases

With the increasing incidence of metabolic diseases year by year and their impact on the incidence of cardiovascular diseases, metabolic diseases have attracted great attention as a major health care problem, but there is still no effective treatment. Oxidative stress and inflammation are the main mechanisms leading to metabolic diseases. T cells are involved in the inflammatory response, which can also regulate the development of metabolic diseases, CD4+ T cells and CD8+ T cells are mainly responsible for the role. Th1 and Th17 differentiated from CD4+ T promote inflammation, while Th2 and Treg inhibit inflammation. CD8+ T cells also contribute to inflammation. The severity and duration of inflammatory reactions can also lead to different degrees of progression of metabolic diseases. Moreover, mTOR, PI3K-Akt, and AMPK signaling pathways play unique roles in the regulation of T cells, which provide a new direction for the treatment of metabolic diseases in the future. In this review, we will elaborate on the role of T cells in regulating inflammation in various metabolic diseases, the signaling pathways that regulate T cells in metabolic diseases, and the latest research progress.

Distinct roles of ORAI1 in T cell-mediated allergic airway inflammation and immunity to influenza A virus infection

T cell activation and function depend on Ca2+ signals mediated by store-operated Ca2+ entry (SOCE) through Ca2+ release-activated Ca2+ (CRAC) channels formed by ORAI1 proteins. We here investigated how SOCE controls T cell function in pulmonary inflammation during a T helper 1 (TH1) cell-mediated response to influenza A virus (IAV) infection and TH2 cell-mediated allergic airway inflammation. T cell-specific deletion of Orai1 did not exacerbate pulmonary inflammation and viral burdens following IAV infection but protected mice from house dust mite-induced allergic airway inflammation. ORAI1 controlled the expression of genes including p53 and E2F transcription factors that regulate the cell cycle in TH2 cells in response to allergen stimulation and the expression of transcription factors and cytokines that regulate TH2 cell function. Systemic application of a CRAC channel blocker suppressed allergic airway inflammation without compromising immunity to IAV infection, suggesting that inhibition of SOCE is a potential treatment for allergic airway disease.

Autoreactive lymphocytes in multiple sclerosis: Pathogenesis and treatment target

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by destruction of the myelin sheath structure. The loss of myelin leads to damage of a neuron’s axon and cell body, which is identified as brain lesions on magnetic resonance image (MRI). The pathogenesis of MS remains largely unknown. However, immune mechanisms, especially those linked to the aberrant lymphocyte activity, are mainly responsible for neuronal damage. Th1 and Th17 populations of lymphocytes were primarily associated with MS pathogenesis. These lymphocytes are essential for differentiation of encephalitogenic CD8⁺ T cell and Th17 lymphocyte crossing the blood brain barrier and targeting myelin sheath in the CNS. B-lymphocytes could also contribute to MS pathogenesis by producing anti-myelin basic protein antibodies. In later studies, aberrant function of Treg and Th9 cells was identified as contributing to MS. This review summarizes the aberrant function and count of lymphocyte, and the contributions of these cell to the mechanisms of MS. Additionally, we have outlined the novel MS therapeutics aimed to amend the aberrant function or counts of these lymphocytes.

Cigarette Smoke and Morphine Promote Treg Plasticity to Th17 via Enhancing Trained Immunity

CD4+ regulatory T cells (Tregs) respond to environmental cues to permit or suppress inflammation, and atherosclerosis weakens Treg suppression and promotes plasticity. However, the effects of smoking plus morphine (SM + M) on Treg plasticity remain unknown. To determine whether SM + M promotes Treg plasticity to T helper 17 (Th17) cells, we analyzed the RNA sequencing data from SM, M, and SM + M treated Tregs and performed knowledge-based and IPA analysis. We demonstrated that (1) SM + M, M, and SM upregulated the transcripts of cytokines, chemokines, and clusters of differentiation (CDs) and modulated the transcripts of kinases and phosphatases in Tregs; (2) SM + M, M, and SM upregulated the transcripts of immunometabolism genes, trained immunity genes, and histone modification enzymes; (3) SM + M increased the transcripts of Th17 transcription factor (TF) RORC and Tfh factor CXCR5 in Tregs; M increased the transcripts of T helper cell 1 (Th1) TF RUNX3 and Th1-Th9 receptor CXCR3; and SM inhibited Treg TGIF1 transcript; (4) six genes upregulated in SM + M Tregs were matched with the top-ranked Th17 pathogenic genes; and 57, 39 genes upregulated in SM + M Tregs were matched with groups II and group III Th17 pathogenic genes, respectively; (5) SM + M upregulated the transcripts of 70 IPA-TFs, 11 iTregs-specific TFs, and 4 iTregs-Th17 shared TFs; and (6) SM + M, M, and SM downregulated Treg suppression TF Rel (c-Rel); and 35 SM + M downregulated genes were overlapped with Rel-/- Treg downregulated genes. These results provide novel insights on the roles of SM + M in reprogramming Treg transcriptomes and Treg plasticity to Th17 cells and novel targets for future therapeutic interventions involving immunosuppression in atherosclerotic cardiovascular diseases, autoimmune diseases, transplantation, and cancers.

Shifting gears: Id3 enables recruitment of E proteins to new targets during T cell development and differentiation

Shifting levels of E proteins and Id factors are pivotal in T cell commitment and differentiation, both in the thymus and in the periphery. Id2 and Id3 are two different factors that prevent E proteins from binding to their target gene cis-regulatory sequences and inducing gene expression. Although they use the same mechanism to suppress E protein activity, Id2 and Id3 play very different roles in T cell development and CD4 T cell differentiation. Id2 imposes an irreversible choice in early T cell precursors between innate and adaptive lineages, which can be thought of as a railway switch that directs T cells down one path or another. By contrast, Id3 acts in a transient fashion downstream of extracellular signals such as T cell receptor (TCR) signaling. TCR-dependent Id3 upregulation results in the dislodging of E proteins from their target sites while chromatin remodeling occurs. After the cessation of Id3 expression, E proteins can reassemble in the context of a new genomic landscape and molecular context that allows induction of different E protein target genes. To describe this mode of action, we have developed the “Clutch” model of differentiation. In this model, Id3 upregulation in response to TCR signaling acts as a clutch that stops E protein activity (“clutch in”) long enough to allow shifting of the genomic landscape into a different “gear”, resulting in accessibility to different E protein target genes once Id3 decreases (“clutch out”) and E proteins can form new complexes on the DNA. While TCR signal strength and cytokine signaling play a role in both peripheral and thymic lineage decisions, the remodeling of chromatin and E protein target genes appears to be more heavily influenced by the cytokine milieu in the periphery, whereas the outcome of Id3 activity during T cell development in the thymus appears to depend more on the TCR signal strength. Thus, while the Clutch model applies to both CD4 T cell differentiation and T cell developmental transitions within the thymus, changes in chromatin accessibility are modulated by biased inputs in these different environments. New emerging technologies should enable a better understanding of the molecular events that happen during these transitions, and how they fit into the gene regulatory networks that drive T cell development and differentiation.

Polychlorinated biphenyl quinone induces immunotoxicity via lymphocytes apoptosis and Th1-Th2 cell imbalance in C57BL/6 mice

Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants distributed worldwide. Existing researches indicated that the immune system is one of the most sensitive indicators of adverse health effects caused by PCBs. We for the first time evaluated the immunotoxic effect of PCB29-pQ, an active quinone-type PCB metabolite. After PCB29-pQ exposure, the body weight of the mice was reduced, but increased the organ index of the spleen and lungs. The morphology and structure of the mouse spleen and lungs were changed, and partial types of lymphocyte subsets in the spleen were significantly reduced. The activation of caspase-3, the significant up-regulation of Bax and the decrease of Bcl-2 indicated occurrence of apoptosis. In addition, mRNA results showed that PCB29-pQ caused the imbalance of Th1/Th2 cytokines and promoted the Th1-type immune response. Taken together, the above results demonstrated that treatment with PCB29-pQ induced spleen immune dysfunction targeting the apoptosis pathway and Th1/Th2 cytokines imbalance in mice. Since the immune system plays a fundamental role in maintaining homeostasis and is strongly involved in the development of diseases, this study provides a new insight into the immunotoxicity mechanism of PCBs.

HIV UTR, LTR, and Epigenetic Immunity

The duel between humans and viruses is unending. In this review, we examine the HIV RNA in the form of un-translated terminal region (UTR), the viral DNA in the form of long terminal repeat (LTR), and the immunity of human DNA in a format of epigenetic regulation. We explore the ways in which the human immune responses to invading pathogenic viral nucleic acids can inhibit HIV infection, exemplified by a chromatin vaccine (cVaccine) to elicit the immunity of our genome—epigenetic immunity towards a cure.

Formaldehyde exposure induces differentiation of regulatory T cells via the NFAT-mediated T cell receptor signalling pathway in Yucatan minipigs

The use of minipigs (Sus scrofa) as a platform for toxicological and pharmacological research is well established. In the present study, we investigated the effect of formaldehyde (FA) exposure on helper T cell-mediated splenic immune responses in Yucatan minipigs. The minipigs were exposed to different inhaled concentrations of FA (0, 2.16, 4.62, or 10.48 mg/m³) for a period of 2 weeks. Immune responses elicited by exposure to FA were determined by assessing physiological parameters, mRNA expression, and cytokine production. Additionally, the distribution of helper T cells and regulatory T (Treg) cells and expression of NFAT families, which are well-known T cell receptor signalling proteins associated with regulatory T cell development, were evaluated. Exposure to FA suppressed the expression of genes associated with Th1 and Th2 cells in minipigs in a concentration-dependent manner. The subsequent production of cytokines also declined post-FA exposure. Furthermore, exposure to FA induced the differentiation of CD4⁺ Foxp3⁺ Treg cells with divergent expression levels of NFAT1 and NFAT2. These results indicated that exposure to FA increased the Treg cell population via the NFAT-mediated T cell receptor signalling pathway, leading to suppression of effector T cell activity with a decline in T cell-related cytokine production.

Cluster analysis of splenocyte microRNAs in the pig reveals key signal regulators of immunomodulation in the host during acute and chronic Toxoplasma gondii infection

BACKGROUND

Toxoplasma gondii is an obligate intracellular protozoan parasite that can cause a geographically widespread zoonosis. Our previous splenocyte microRNA profile analyses of pig infected with T. gondii revealed that the coordination of a large number of miRNAs regulates the host immune response during infection. However, the functions of other miRNAs involved in the immune regulation during T. gondii infection are not yet known.

METHODS

Clustering analysis was performed by K-means, self-organizing map (SOM), and hierarchical clustering to obtain miRNA groups with the similar expression patterns. Then, the target genes of the miRNA group in each subcluster were further analyzed for functional enrichment by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome pathway to recognize the key signaling molecules and the regulatory signatures of the innate and adaptive immune responses of the host during T. gondii infection.

RESULTS

A total of 252 miRNAs were successfully divided into 22 subclusters by K-means clustering (designated as K1-K22), 29 subclusters by SOM clustering (designated as SOM1-SOM29), and six subclusters by hierarchical clustering (designated as H1-H6) based on their dynamic expression levels in the different infection stages. A total of 634, 660, and 477 GO terms, 15, 26, and 14 KEGG pathways, and 16, 15, and 7 Reactome pathways were significantly enriched by K-means, SOM, and hierarchical clustering, respectively. Of note, up to 22 miRNAs mainly showing downregulated expression at 50 days post-infection (dpi) were grouped into one subcluster (namely subcluster H3-K17-SOM1) through the three algorithms. Functional analysis revealed that a large group of immunomodulatory signaling molecules were controlled by the different miRNA groups to regulate multiple immune processes, for instance, IL-1-mediated cellular response and Th1/Th2 cell differentiation partly depending on Notch signaling transduction for subclusters K1 and K2, innate immune response involved in neutrophil degranulation and TLR4 cascade signaling for subcluster K15, B cell activation for subclusters SOM17, SOM1, and SOM25, leukocyte migration, and chemokine activity for subcluster SOM9, cytokine-cytokine receptor interaction for subcluster H2, and interleukin production, chemotaxis of immune cells, chemokine signaling pathway, and C-type lectin receptor signaling pathway for subcluster H3-K17-SOM1.

CONCLUSIONS

Cluster analysis of splenocyte microRNAs in the pig revealed key regulatory properties of subcluster miRNA molecules and important features in the immune regulation induced by acute and chronic T. gondii infection. These results contribute new insight into the identification of physiological immune responses and maintenance of tolerance in pig spleen tissues during T. gondii infection.

Targeted Immunotherapy for Autoimmune Disease

In the past few decades, biological drugs and small molecule inhibitors targeting inflammatory cytokines, immune cells, and intracellular kinases have become the standard-of-care to treat autoimmune diseases. Inhibition of TNF, IL-6, IL-17, and IL-23 has revolutionized the treatment of autoimmune diseases, such as rheumatoid arthritis, ankylosing spondylitis, and psoriasis. B cell depletion therapy using anti-CD20 mAbs has shown promising results in patients with neuroinflammatory diseases, and inhibition of B cell survival factors is approved for treatment of systemic lupus erythematosus. Targeting co-stimulatory molecules expressed on Ag-presenting cells and T cells is also expected to have therapeutic potential in autoimmune diseases by modulating T cell function. Recently, small molecule kinase inhibitors targeting the JAK family, which is responsible for signal transduction from multiple receptors, have garnered great interest in the field of autoimmune and hematologic diseases. However, there are still unmet medical needs in terms of therapeutic efficacy and safety profiles. Emerging therapies aim to induce immune tolerance without compromising immune function, using advanced molecular engineering techniques.

When a Friend Becomes Your Enemy: Natural Killer Cells in Atherosclerosis and Atherosclerosis-Associated Risk Factors

Atherosclerosis (ATS), the change in structure and function of arteries with associated lesion formation and altered blood flow, is the leading cause of cardiovascular disease, the number one killer worldwide. Beyond dyslipidemia, chronic inflammation, together with aberrant phenotype and function of cells of both the innate and adaptive immune system, are now recognized as relevant contributors to atherosclerosis onset and progression. While the role of macrophages and T cells in atherosclerosis has been addressed in several studies, Natural Killer cells (NKs) represent a poorly explored immune cell type, that deserves attention, due to NKs’ emerging contribution to vascular homeostasis. Furthermore, the possibility to re-polarize the immune system has emerged as a relevant tool to design new therapies, with some succesfull exmples in the field of cancer immunotherapy. Thus, a deeper knowledge of NK cell pathophysiology in the context of atherosclerosis and atherosclerosis-associated risk factors could help developing new preventive and treatment strategies, and decipher the complex scenario/history from “the risk factors for atherosclerosis” Here, we review the current knowledge about NK cell phenotype and activities in atherosclerosis and selected atherosclerosis risk factors, namely type-2 diabetes and obesity, and discuss the related NK-cell oriented environmental signals.

Revisiting the Principles of Designing a Vaccine

Immune principles formulated by Jenner, Pasteur, and early immunologists served as fundamental propositions for vaccine discovery against many dreadful pathogens. However, decisive success in the form of an efficacious vaccine still eludes for diseases such as tuberculosis, leishmaniasis, and trypanosomiasis. Several antileishmanial vaccine trials have been undertaken in past decades incorporating live, attenuated, killed, or subunit vaccination, but the goal remains unmet. In light of the above facts, we have to reassess the principles of vaccination by dissecting factors associated with the hosts' immune response. This chapter discusses the pathogen-associated perturbations at various junctures during the generation of the immune response which inhibits antigenic processing, presentation, or remodels memory T cell repertoire. This can lead to ineffective priming or inappropriate activation of memory T cells during challenge infection. Thus, despite a protective primary response, vaccine failure can occur due to altered immune environments in the presence of pathogens.

T helper cells in depression: central role of Th17 cells

Depression is one of the most common neuropsychiatric disorders in the world. While conventional pharmaceutical therapy targets monoaminergic pathway dysfunction, it has not been totally successful in terms of positive outcomes, remission, and preventing relapses. There is an increasing amount of evidence that neuroinflammation may play a significant part in the pathophysiology of depression. Among the key components of the neuroinflammatory pathways already known to be active are the T helper (Th) cells, especially Th17 cells. While various preclinical and clinical studies have reported increased levels of Th17 cells in both serum and brain tissue of laboratory model animals, contradictory results have argued against a pertinent role of Th17 cells in depression. Recent studies have also revealed a role for more pathogenic and inflammatory subsets of Th17 in depression, as well as IL-17A and Th17 cells in non-responsiveness to conventional antidepressant therapy. Despite recent advances, there is still a significant knowledge gap concerning the exact mechanism by which Th17 cells influence neuroinflammation in depression. This review first provides a short introduction to the major findings that led to the discovery of the role of Th cells in depression. The major subsets of Th cells known to be involved in neuroimmunology of depression, such as Th1, Th17, and T regulatory cells, are subsequently described, with an in-depth discussion on current knowledge about Th17 cells in depression.

Clinical and immunological allergy assessment in cancer patients

Cancer is associated with immunodeficiency, while allergies result from immune system hyperactivity mediated by cytokines and immunoglobulins. The purpose of this study was to determine the relationship between immune environment of specific cancers and allergies, emphasizing cytokines related to Th1 and Th2 responses associated with IgE. 80 adults were distributed into two groups: control (n = 20) and cancer (n = 60), distributed in three subgroups (n = 20), head and neck, stomach, and prostate cancers. This study compared Th1 (IL-2) and Th2 (IL-4) parameters, anti-inflammatory, pro-inflammatory, or regulatory profile regarding both IgE levels and reported allergies, by means of clinical manifestations and IgE, IL-1β, IL-2, IL-4, IL-17, and TGF-β serum concentration. Clinically allergies were observed in 50% of the control group and in 20% of the cancer group (p = 0.009). IL-2 cytokine and TGF-β concentrations were higher in the patients with cancer as compared to the control (p < 0.005). However, there were IL-4, IL-17, and IL-1β decreases in the patients with cancer (p < 0.05). No correlation was observed between the cytokines studied and IgE and clinically proven allergies in both investigated groups. There was an inverse association between cancer and clinical allergy manifestations. In head and neck, stomach, and prostate cancers, an immunosuppressive serum tumor environment was predominant. There was no difference in cytokines related to Th1 and Th2 parameters in relation to IgE. No correlation was found between clinically proved allergies and immunity markers related to the same allergens.

Extracellular traps released by antimicrobial TH17 cells contribute to host defense

TH17 cell subpopulations have been defined that contribute to inflammation and homeostasis, yet the characteristics of TH17 cells that contribute to host defense against infection are not clear. To elucidate the antimicrobial machinery of the TH17 subset, we studied the response to Cutibacterium acnes, a skin commensal that is resistant to IL-26, the only known TH17-secreted protein with direct antimicrobial activity. We generated C. acnes-specific antimicrobial TH17 clones (AMTH17) with varying antimicrobial activity against C. acnes, which we correlated by RNA sequencing to the expression of transcripts encoding proteins that contribute to antimicrobial activity. Additionally, we validated that AMTH17-mediated killing of C. acnes and bacterial pathogens was dependent on the secretion of granulysin, granzyme B, perforin, and histone H2B. We found that AMTH17 cells can release fibrous structures composed of DNA decorated with histone H2B that entangle C. acnes that we call T cell extracellular traps (TETs). Within acne lesions, H2B and IL-17 colocalized in CD4+ T cells, in proximity to TETs in the extracellular space composed of DNA decorated with H2B. This study identifies a functionally distinct subpopulation of TH17 cells with an ability to form TETs containing secreted antimicrobial proteins that capture and kill bacteria.

Inflammation and tumor progression: signaling pathways and targeted intervention

Cancer development and its response to therapy are regulated by inflammation, which either promotes or suppresses tumor progression, potentially displaying opposing effects on therapeutic outcomes. Chronic inflammation facilitates tumor progression and treatment resistance, whereas induction of acute inflammatory reactions often stimulates the maturation of dendritic cells (DCs) and antigen presentation, leading to anti-tumor immune responses. In addition, multiple signaling pathways, such as nuclear factor kappa B (NF-kB), Janus kinase/signal transducers and activators of transcription (JAK-STAT), toll-like receptor (TLR) pathways, cGAS/STING, and mitogen-activated protein kinase (MAPK); inflammatory factors, including cytokines (e.g., interleukin (IL), interferon (IFN), and tumor necrosis factor (TNF)-α), chemokines (e.g., C-C motif chemokine ligands (CCLs) and C-X-C motif chemokine ligands (CXCLs)), growth factors (e.g., vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β), and inflammasome; as well as inflammatory metabolites including prostaglandins, leukotrienes, thromboxane, and specialized proresolving mediators (SPM), have been identified as pivotal regulators of the initiation and resolution of inflammation. Nowadays, local irradiation, recombinant cytokines, neutralizing antibodies, small-molecule inhibitors, DC vaccines, oncolytic viruses, TLR agonists, and SPM have been developed to specifically modulate inflammation in cancer therapy, with some of these factors already undergoing clinical trials. Herein, we discuss the initiation and resolution of inflammation, the crosstalk between tumor development and inflammatory processes. We also highlight potential targets for harnessing inflammation in the treatment of cancer.

Regulation of in vivo delivery of nanomedicines by herbal medicines

Nanomedicines are of increasing scrutiny due to their improved efficacy and/or mitigated side effects. They can be integrated with many other therapeutics to further boost the clinical benefits. Among those, herbal medicines are arousing great interest to be combined with nanomedicines to exert synergistic effects in multifaceted mechanisms. The in vivo performance of nanomedicines which determines the therapeutic efficacy and safety is believed to be heavily influenced by the physio-pathological characters of the body. Activation of multiple immune factors, e.g., complement system, phagocytic cells, lymphocytes, and among many others, can affect the fate of nanomedicines in blood circulation, biodistribution, interaction with single cells and intracellular transport. Immunomodulatory effects and metabolic regulation by herbal medicines have been widely witnessed during the past decades, which alter the physio-pathological conditions and dramatically affect in vivo delivery of nanomedicines. In this review, we summarize recent progress of understanding on the in vivo delivery process of nanomedicines and analyze the major affecting factors that regulate the interaction of nanomedicines with organisms. We discuss the immunomodulatory roles and metabolic regulation by herbal medicines and their effects on in vivo delivery process of nanomedicines, as well as the prospective clinical benefits from the combination of nanomedicines and herbal medicines.

Spatially Resolved Mass Spectrometry at the Single Cell: Recent Innovations in Proteomics and Metabolomics

Biological systems are composed of heterogeneous populations of cells that intercommunicate to form a functional living tissue. Biological function varies greatly across populations of cells, as each single cell has a unique transcriptome, proteome, and metabolome that translates to functional differences within single species and across kingdoms. Over the past decade, substantial advancements in our ability to characterize omic profiles on a single cell level have occurred, including in multiple spectroscopic and mass spectrometry (MS)-based techniques. Of these technologies, spatially resolved mass spectrometry approaches, including mass spectrometry imaging (MSI), have shown the most progress for single cell proteomics and metabolomics. For example, reporter-based methods using heavy metal tags have allowed for targeted MS investigation of the proteome at the subcellular level, and development of technologies such as laser ablation electrospray ionization mass spectrometry (LAESI-MS) now mean that dynamic metabolomics can be performed in situ. In this Perspective, we showcase advancements in single cell spatial metabolomics and proteomics over the past decade and highlight important aspects related to high-throughput screening, data analysis, and more which are vital to the success of achieving proteomic and metabolomic profiling at the single cell scale. Finally, using this broad literature summary, we provide a perspective on how the next decade may unfold in the area of single cell MS-based proteomics and metabolomics.

CD4 T Helper Cell Subsets and Related Human Immunological Disorders

The immune system plays a critical role in protecting hosts from the invasion of organisms. CD4 T cells, as a key component of the immune system, are central in orchestrating adaptive immune responses. After decades of investigation, five major CD4 T helper cell (Th) subsets have been identified: Th1, Th2, Th17, Treg (T regulatory), and Tfh (follicular T helper) cells. Th1 cells, defined by the expression of lineage cytokine interferon (IFN)-γ and the master transcription factor T-bet, participate in type 1 immune responses to intracellular pathogens such as mycobacterial species and viruses; Th2 cells, defined by the expression of lineage cytokines interleukin (IL)-4/IL-5/IL-13 and the master transcription factor GAΤA3, participate in type 2 immune responses to larger extracellular pathogens such as helminths; Th17 cells, defined by the expression of lineage cytokines IL-17/IL-22 and the master transcription factor RORγt, participate in type 3 immune responses to extracellular pathogens including some bacteria and fungi; Tfh cells, by producing IL-21 and expressing Bcl6, help B cells produce corresponding antibodies; whereas Foxp3-expressing Treg cells, unlike Th1/Th2/Th17/Tfh exerting their effector functions, regulate immune responses to maintain immune cell homeostasis and prevent immunopathology. Interestingly, innate lymphoid cells (ILCs) have been found to mimic the functions of three major effector CD4 T helper subsets (Th1, Th2, and Th17) and thus can also be divided into three major subsets: ILC1s, ILC2s, and ILC3s. In this review, we will discuss the differentiation and functions of each CD4 T helper cell subset in the context of ILCs and human diseases associated with the dysregulation of these lymphocyte subsets particularly caused by monogenic mutations.

Formaldehyde exposure induces regulatory T cell-mediated immunosuppression via calcineurin-NFAT signalling pathway

In this study, we investigated the effects of Formaldehyde (FA) exposure on splenic immune responses wherein helper T cells become activated and differentiate into effector T and regulatory T cells. BALB/c mice were exposed to two FA concentrations (1.38 mg/m3 and 5.36 mg/m3) for 4 h/day and 5 days/week for 2 weeks. FA-induced immune responses were examined by the production of cytokines, expression of mRNAs, and distributions of helper T cells and regulatory T cells. Moreover, expression of calcineurin and NFATs, regulatory T cell-related signalling proteins, were evaluated. FA exposure suppressed Th2-, Th1-, and Th17-related splenic cytokines in a dose-dependent manner. mRNA expression of splenic cytokines was also decreased by FA exposure, which correlated with decreased cytokine expression. In parallel, FA exposure promoted T cell differentiation into regulatory T cells in a dose-dependent manner supported by the expression of calcineurin and NFAT1. Taken together, our results indicated that FA exposure increases the number of regulatory T cells via calcineurin-NFAT signalling, thereby leading to effector T cell activity suppression with decreased T cell-related cytokine secretion and mRNA expression. These findings provide insight into the mechanisms underlying the adverse effects of FA and accordingly have general implications for human health, particularly in occupational settings.

FOXP3rs3761548 gene variant and interleukin-35 serum levels as biomarkers in patients with multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS). Aberrant expression of transcription factor forkhead box P3 (FoxP3) has been suggested to underlie different immunological disorders as FOXP3 expression is essential for T regulatory cells (Tregs) to maintain their suppressive and anti-inflammatory functions and exert immunologic self-tolerance. Interleukin-35 (IL-35) is an important immunosuppressive cytokine that is produced mainly by CD4+ FOXP3+ Tregs.

OBJECTIVES

To assess the possible role of the FOXP3 rs3761548 (C/A) single-nucleotide variation (SNV) in relapsing-remitting multiple sclerosis (RRMS). Also, measurement of the serum IL-35 concentration and study its relation to different genotypes and the degree of disease-related disability.

METHODS

A total of 100 RRMS patients and 90 healthy control subjects were subjected to genotyping for the FOXP3 (rs3761548) variant by TaqMan real-time PCR, and measurement of the IL-35 level in their sera by Elisa.

RESULTS

The frequencies of the AA genotype and A allele were significantly higher in the MS patients than in the healthy controls (P=0.008, OR=2.53, 95% CI=1.27-5.04; P=0.001, OR=1.98, 95% CI=1.31-3.00, respectively). There was a significant association between FOXP3 rs3761548 variant and female MS patients. The serum IL-35 level was significantly higher in MS patients (1372 [575-2192] pg/mL) compared to healthy controls (604 [454-696] pg/mL) (P<0.0001). No significant differences were found between the different FOXP3 genotypes and EDSS score (P=0.730).

CONCLUSION

The FOXP3rs3761548 gene variant may influence the genetic susceptibility to MS rather than affecting its course, severity or progression. The serum IL-35 level might have a role in the development of the disease, however its role in disease-related disability is questionable.

A Dynamic Quantitative Systems Pharmacology Model of Inflammatory Bowel Disease: Part 1 - Model Framework

A mechanistic, multistate, mathematical model of inflammatory bowel disease (IBD) was developed by including key biological mechanisms in blood and gut, including cell differentiation, cytokine production, and clinical biomarkers. The model structure is consistent between healthy volunteers and IBD disease phenotype, with 24 parameters changed between diseases. Modular nature of the model allows for easy incorporation of new mechanisms or modification of existing interactions. Model simulations for steady-state levels of proteins and cells in the blood and gut using a population approach are consistent with published data. By simulating the response of two clinical biomarkers, C-reactive protein and fecal calprotectin, to parameter perturbations, the model explores hypotheses for possible treatment mechanisms. With additional experimental validation and addition of drug treatments, the model provides a platform to test hypothesis on treatment effects in IBD.

Mechanisms of TREG cell adaptation to inflammation

Inflammation is an important defense mechanism. In this complex and dynamic process, drastic changes in the tissue micro-environment play key roles in dictating the nature of the evolving immune response. However, uncontrolled inflammation is detrimental, leading to unwanted cellular damage, loss of physiological functions, and even death. As such, the immune system possesses tools to limit inflammation while ensuring rapid and effective clearance of the inflammatory trigger. Foxp3⁺ regulatory T (T_REG ) cells, a potently immunosuppressive CD4⁺ T cell subset, play a crucial role in immune tolerance by controlling the extent of the response to self and non-self Ags, all-the-while promoting a quick return to immune homeostasis. T_REG cells adapt to changes in the local micro-environment enabling them to migrate, proliferate, survive, differentiate, and tailor their suppressive ability at inflamed sites. Several inflammation-associated factors can impact T_REG cell functional adaptation in situ including locally released alarmins, oxygen availability, tissue acidity and osmolarity and nutrient availability. Here, we review some of these key signals and pathways that control the adaptation of T_REG cell function in inflammatory settings.

Depletion of ID3 enhances mesenchymal stem cells therapy by targeting BMP4 in Sjögren's syndrome

Mesenchymal stem cell (MSCs) transplantation has been used to treat Sjögren’s syndrome (SS) based on the immunoregulatory properties of MSCs. However, the effectiveness need improving and its underlying intrinsic mechanisms remain largely unknown. Here, we show that Id3 is upregulated in bone marrow-derived MSCs (BMMSCs) isolated from NOD/ShiLtJ mice, a widely used SS model, compared with ICR mice as control, suggesting that it functions in SS development and therapy. Transplantation of Id3-deficient BMMSCs rescues salivary gland function more effective than wild-type BMMSCs in NOD/ShiLtJ mice. Mechanistically, we show that ID3 negatively regulated BMP4 expression by preventing binding of basic helix–loop–helix protein E2A to the promoter of the Bmp4 gene. BMP4 in turn promoted PGE2 production in MSCs, and exhibited enhanced suppressive activities of T-cell proliferation and Th1 differentiation. Importantly, BMMSCs from SS patients showed significantly lower BMP4 and PGE2 expression than those from healthy individuals. Taken together, our findings revealed the targeting Id3 may be therapeutically useful for improving MSC immunoregulation and effectiveness of MSCs therapy for SS.

Immunomodulatory roles of human herpesvirus-encoded microRNA in host-virus interaction

Human herpesviruses (HHV) are large, double stranded, DNA viruses with high seroprevalence across the globe. Clinical manifestation of primary HHV infection resolve shortly, however, this period is prolonged in immunocompromised patients or individuals with suppressed immunity. Examining molecular mechanisms of HHV-encoded virulence factors can provide finer details of HHV-host interaction. A unique genetic feature of most members of HHV is that they encode multiple microRNAs (miR). In this review, I will provide mechanistic insights into the immunomodulatory functions of herpesvirus-encoded viral miR (v-miR) that favor viral persistence and spread by ingenious immune evasion schemes. Similar to host miR, v-miR can simultaneously regulate expression of multiple transcripts including host- and virus-derived. V-miRs, by virtue of their direct interaction with various transcripts, can regulate expression of critical components of host innate and adaptive immune system. V-miRs are also exported through exosomal route and gain entry into various cells even at distant sites, thereby allowing HHV to manipulate cellular and tissue immunity. Targeting v-miR may serve as a novel and promising therapeutic candidate to mitigate HHV-mediated clinical manifestations.

Intracellular Energy Variability Modulates Cellular Decision-Making Capacity

Cells generate phenotypic diversity both during development and in response to stressful and changing environments, aiding survival. Functionally vital cell fate decisions from a range of phenotypic choices are made by regulatory networks, the dynamics of which rely on gene expression and hence depend on the cellular energy budget (and particularly ATP levels). However, despite pronounced cell-to-cell ATP differences observed across biological systems, the influence of energy availability on regulatory network dynamics is often overlooked as a cellular decision-making modulator, limiting our knowledge of how energy budgets affect cell behaviour. Here, we consider a mathematical model of a highly generalisable, ATP-dependent, decision-making regulatory network, and show that cell-to-cell ATP variability changes the sets of decisions a cell can make. Our model shows that increasing intracellular energy levels can increase the number of supported stable phenotypes, corresponding to increased decision-making capacity. Model cells with sub-threshold intracellular energy are limited to a singular phenotype, forcing the adoption of a specific cell fate. We suggest that energetic differences between cells may be an important consideration to help explain observed variability in cellular decision-making across biological systems.

Cigarette smoke triggers inflammation mediated by autophagy in BEAS-2B cells

Cigarette smoking, as an individual consumption habit, is associated with a variety of related diseases. Exposure of cigarette smoke was reported to induce autophagy and inflammation in experimental animals and humans. However, the toxicity mechanism of cigarette smoke in organisms has not been entirely investigated. In this present study, we studied the role of autophagy played in the inflammation caused by cigarette smoke in human bronchial epithelial cells (BEAS-2B), as well as the role of the phosphatidylinositol 3-kinase (PI3K) signaling pathway and the mitogen-activated protein kinase (MAPK) signaling pathways underlying autophagy and inflammation. We found that cigarette smoke induced autophagy and inflammation in BEAS-2B, and the blockage of autophagy significantly reduced the release levels of IL-1β, IL-6 and IL-8 in BEAS-2B exposed to cigarette smoke for 24 h. Cigarette smoke downregulated the activity of PI3K/Akt/mTOR pathway and elevated the activity of MAPK pathways. Pretreatment of autophagic inhibitor could inhibit autophagy and the activity of JNK and p38 pathways. These results suggested that cigarette smoke-induced autophagy triggered inflammation through the activation of JNK and p38 pathways, which might contribute to understanding the adverse outcome pathways induced by cigarette smoke exposure and provide the information about the risk assessment of tobacco products.

IL-17 receptor-based signaling and implications for disease

IL-17 is a highly versatile pro-inflammatory cytokine crucial for a variety of processes, including host defense, tissue repair, the pathogenesis of inflammatory disease and the progression of cancer. In contrast to its profound impact in vivo, IL-17 exhibits surprisingly moderate activity in cell-culture models, which presents a major knowledge gap about the molecular mechanisms of IL-17 signaling. Emerging studies are revealing a new dimension of complexity in the IL-17 pathway that may help explain its potent and diverse in vivo functions. Discoveries of new mRNA stabilizers and receptor-directed mRNA metabolism have provided insights into the means by which IL-17 cooperates functionally with other stimuli in driving inflammation, whether beneficial or destructive. The integration of IL-17 with growth-receptor signaling in specific cell types offers new understanding of the mitogenic effect of IL-17 on tissue repair and cancer. This Review summarizes new developments in IL-17 signaling and their pathophysiological implications.

BAY 41-2272 inhibits human T lymphocyte functions

BAY 41-2272 increases guanosine 3', 5'-cyclic monophosphate (cGMP) levels by stimulating soluble guanylate cyclase (sGC). In this study, we evaluated the effect of BAY 41-2272 on human T lymphocyte functions. Pretreating T cells for 24 h with BAY 41-2272 at 3 μM and 30 μM, followed by activation with 90 nM phorbol myristate acetate (PMA), inhibited interferon-gamma (IFN-γ) production, with 3 μM and 30 μM BAY causing 16.5-fold and 12.1-fold inhibition, respectively, compared to PMA alone (p < 0.05, one-way ANOVA followed by Tukey's test). We also observed suppressive effects on the expression of CD69, with 30 μM BAY causing 3.55-fold lower expression than PMA/ionomycin (p < 0.001 one-way ANOVA followed by Tukey's test), and T-bet, with 30 μM BAY causing 1.47-fold lower expression than PMA/ionomycin (p < 0.05, one-way ANOVA test followed by Tukey's test). Additionally, T lymphocyte proliferation was reduced 2.13-fold and 4.3-fold, respectively, by 3 μM BAY and 30 μM BAY compared to PMA/ionomycin (p < 0.01, p < 0.001, one-way ANOVA followed by Tukey's test). BAY 41-2272 inhibits human T lymphocyte function and may be explored as an immunomodulatory drug in patients with autoimmune/inflammatory diseases and lymphoproliferative syndromes.

The versatile plasmacytoid dendritic cell: Function, heterogeneity, and plasticity

Since their identification as the natural interferon-producing cell two decades ago, plasmacytoid dendritic cells (pDCs) have been attributed diverse functions in the immune response. Their most well characterized function is innate, i.e., their rapid and robust production of type-I interferon (IFN-I) in response to viruses. However, pDCs have also been implicated in antigen presentation, activation of adaptive immune responses and immunoregulation. The mechanisms by which pDCs enact these diverse functions are poorly understood. One central debate is whether these functions are carried out by different pDC subpopulations or by plasticity in the pDC compartment. This chapter summarizes the latest reports regarding pDC function, heterogeneity, cell conversion and environmentally influenced plasticity, as well as the role of pDCs in infection, autoimmunity and cancer.

Regulation of CD39 expression in ATP-P2Y2R-mediated alcoholic liver steatosis and inflammation

Inflammation plays a central role in the progression of alcoholic liver disease. ATP-P2Y2R signaling and CD39 play an important role in various diseases, but little is known about their role in alcoholic liver steatosis and inflammation. As a transmembrane hydrolase, CD39 hydrolyzes ATP, while the mutual regulation of CD39 and ATP-P2Y2R in alcoholic steatohepatitis is poorly understood. Here, we found that the expression of ATP, P2Y2R, and CD39 is increased significantly both in the liver of alcohol-fed mice and alcohol-induced RAW264.7 cell lines. In this study, C57BL/6 mice were intrapretationally injected with P2Y2R inhibitor suramin from day 4 until day 10 during the induction of a chronic/binge drinking model. Pharmacological blockade of P2Y2R largely prevents liver damage, lipid accumulation, and inflammation, with concomitant down-expression of CD39 in liver. We found that the inhibition of P2Y2R in vitro reduces inflammation via down-expression of interleukin 6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-alpha (TNF-α), and the expression of CD39 was reduced, whereas the activation of P2Y2R showed an opposite effect. Silencing of CD39 promoted the expression of ATP and P2Y2R. These results indicate that CD39 attenuates alcohol-induced steatohepatitis by scavenging extracellular ATP to indirectly regulate the expression of P2Y2R. Interestingly, P2Y2R paradoxically boosts CD39 activity. Thus, blockade of the extracellular ATP-P2Y2R signalling represents a potential therapeutic approach against alcoholic liver disease, and CD39 is a potential therapeutic target.

Epigenetic mechanisms regulating T-cell responses

During the last decade, advances in sequencing technologies allowed production of a wealth of information on epigenetic modifications in T cells. Epigenome maps, in combination with mechanistic studies, have demonstrated that T cells undergo extensive epigenome remodeling in response to signals, which has a strong effect on phenotypic stability and function of lymphocytes. In this review we focus on DNA methylation, histone modifications, and chromatin structure as important epigenetic mechanisms involved in controlling T-cell responses. In particular, we discuss epigenetic processes in light of the development, activation, and differentiation of CD4⁺ T helper (T_H), regulatory T, and CD8⁺ T cells. As central aspects of the adaptive immune system, we review mechanisms that ensure molecular memory, stability, plasticity, and exhaustion of T cells. We further discuss the effect of the tissue environment on imprinting T-cell epigenomes with potential implications for immunotherapy.

Glucocorticoids-All-Rounders Tackling the Versatile Players of the Immune System

Glucocorticoids regulate fundamental processes of the human body and control cellular functions such as cell metabolism, growth, differentiation, and apoptosis. Moreover, endogenous glucocorticoids link the endocrine and immune system and ensure the correct function of inflammatory events during tissue repair, regeneration, and pathogen elimination via genomic and rapid non-genomic pathways. Due to their strong immunosuppressive, anti-inflammatory and anti-allergic effects on immune cells, tissues and organs, glucocorticoids significantly improve the quality of life of many patients suffering from diseases caused by a dysregulated immune system. Despite the multitude and seriousness of glucocorticoid-related adverse events including diabetes mellitus, osteoporosis and infections, these agents remain indispensable, representing the most powerful, and cost-effective drugs in the treatment of a wide range of rheumatic diseases. These include rheumatoid arthritis, vasculitis, and connective tissue diseases, as well as many other pathological conditions of the immune system. Depending on the therapeutically affected cell type, glucocorticoid actions strongly vary among different diseases. While immune responses always represent complex reactions involving different cells and cellular processes, specific immune cell populations with key responsibilities driving the pathological mechanisms can be identified for certain autoimmune diseases. In this review, we will focus on the mechanisms of action of glucocorticoids on various leukocyte populations, exemplarily portraying different autoimmune diseases as heterogeneous targets of glucocorticoid actions: (i) Abnormalities in the innate immune response play a crucial role in the initiation and perpetuation of giant cell arteritis (GCA). (ii) Specific types of CD4+ T helper (Th) lymphocytes, namely Th1 and Th17 cells, represent important players in the establishment and course of rheumatoid arthritis (RA), whereas (iii) B cells have emerged as central players in systemic lupus erythematosus (SLE). (iv) Allergic reactions are mainly triggered by several different cytokines released by activated Th2 lymphocytes. Using these examples, we aim to illustrate the versatile modulating effects of glucocorticoids on the immune system. In contrast, in the treatment of lymphoproliferative disorders the pro-apoptotic action of glucocorticoids prevails, but their mechanisms differ depending on the type of cancer. Therefore, we will also give a brief insight into the current knowledge of the mode of glucocorticoid action in oncological treatment focusing on leukemia.

Protium javanicum Burm. Methanol Extract Attenuates LPS-Induced Inflammatory Activities in Macrophage-Like RAW264.7 Cells

Protium javanicum Burm. f. is a medicinal plant used in traditional medicine. Gum and oleoresins from this plant have been used as anti-inflammatory agents for treating ulcers, headaches, eyelid inflammation, and rheumatic pain. However, its anti-inflammatory mechanism of action is still unknown. To better understand the mechanism, we used lipopolysaccharide- (LPS-) treated RAW264.7 cells to measure inflammatory mediators with the Griess assay and to identify target signaling molecules by immunoblot analysis. In this study, we report that the Protium javanicum methanol extract (Pj-ME) plays an important role in suppressing nitric oxide (NO) levels without cytotoxicity. The effect of Pj-ME in LPS-induced expression leads to reduced inflammatory cytokine expression, specifically inducible nitric oxide synthase (iNOS), cyclooxygenase (COX-2), and tumor necrosis factor (TNF-α). Pj-ME significantly inhibited LPS-induced protein expression of the nuclear factor-kappa B (NF-κB) signaling pathway in a time-dependent manner. Syk and Src were identified as putative signaling molecules of Pj-ME-mediated anti-inflammatory activity, which were inhibited by Pj-ME. We demonstrated that Pj-ME controls the STAT3 signaling pathway by suppressing STAT3 and JAK phosphorylation and also downregulates the gene expression of IL-6. Therefore, these results elucidate Pj-ME as a novel anti-inflammatory naturally derived drug with anti-inflammatory and antioxidant properties which may be subject to therapeutic and prognostic relevance.

Altered frequency and function of spleen CTLA-4+Tim-3+ T cells are associated with miscarriage†

Normal pregnancy is associated with several immune adaptations in both systemic and local maternal-fetal interface to allow the growth of semi-allogeneic conceptus. A failure in maternal immune tolerance to the fetus may result in abnormal pregnancies, such as recurrent spontaneous abortion. The regulation of T-cell homeostasis during pregnancy has important implications for maternal tolerance and immunity. Cytotoxic T-lymphocyte antigen-4 (CTLA-4) and T-cell immunoglobulin mucin-3 (Tim-3) are important negative immune regulatory molecules involved in viral persistence and tumor metastasis. Here we described the lower frequency of splenic T cells co-expressing CTLA-4 and Tim-3 accompanied by higher levels of proinflammatory but lower anti-inflammatory cytokines production in abortion-prone mouse model. Blockade of CTLA-4 and Tim-3 pathways leaded to the dysfunction of splenic T cells. By the higher expression during normal pregnancy, CTLA-4 and Tim-3 co-expression on splenic T cells linked to immunosuppressive phenotype. As the spleen is an important site for peripheral immune activation, our data suggest potential noninvasive biomarkers and therapeutic targets for miscarriage.

Computation of Robust Minimal Intervention Sets in Multi-Valued Biological Regulatory Networks

Enabled by rapid advances in computational sciences, in silico logical modeling of complex and large biological networks is more and more feasible making it an increasingly popular approach among biologists. Automated high-throughput, drug target identification is one of the primary goals of this in silico network biology. Targets identified in this way are then used to mine a library of drug chemical compounds in order to identify appropriate therapies. While identification of drug targets is exhaustively feasible on small networks, it remains computationally difficult on moderate and larger models. Moreover, there are several important constraints such as off-target effects, efficacy and safety that should be integrated into the identification of targets if the intention is translation to the clinical space. Here we introduce numerical constraints whereby efficacy is represented by efficiency in response and robustness of outcome. This paper introduces an algorithm that relies on a Constraint Satisfaction (CS) technique to efficiently compute the Minimal Intervention Sets (MIS) within a set of often complex clinical safety constraints with the aim of identifying the smallest least invasive set of targets pharmacologically accessible for therapy that most efficiently and reliably achieve the desired outcome.

The cytokine environment influence on human skin-derived T cells

Skin resident T cells provide immediate immunologic responses at their specific location and play a role in the pathogenesis of skin diseases such as psoriasis. Recently, IL-9-producing T cells were described as a major T-cell subtype present in the skin, but knowledge on the biology and in situ regulation of this T-cell subtype is scarce. Here, we investigated the cytokine influence on skin T cells with focus on IL-9-producing T cells because a better understanding of their biology may identify novel therapeutic approaches. Healthy human skin biopsies were cultured either in the presence of IL-2, IL-4, and TGF-β [T helper (T_h)9-promoting condition (T_h9-PC)] or IL-2 and IL-15 [standard condition (SC)]. Paired analysis of enzymatically isolated skin T cells and emigrated T cells after 4 wk of skin culture showed significant alterations of T-cell phenotypes, cytokine production, and IL-9-producing T-cell frequency. RNA sequencing analysis revealed differentially regulated pathways and identified CXCL8 and CXCL13 as top up-regulated genes in T_h9-PC compared with SC. Functionally supernatant of stimulated skin-derived T cells, CXCL8 and CXCL13 increased neutrophil survival. We report that the cytokine environment alters skin-derived T-cell phenotype and functional properties.-Kienzl, P., Polacek, R., Reithofer, M., Reitermaier, R., Hagenbach, P., Tajpara, P., Vierhapper, M., Gschwandtner, M., Mildner, M. Jahn-Schmid, B., Elbe-Bürger, A. The cytokine environment influence on human skin-derived T cells.

Nucleic Acid Sensing in Allergic Disorders

Recent advances indicate that there is crosstalk between allergic disorders and nucleic acid sensing. Triggers that activate inflammatory mechanisms via nucleic acid sensors affect both allergic phenotypes and anti-viral responses, depending on the timing and the order of exposure. Viral respiratory infections, such as those caused by the rhinovirus, influenza, and respiratory syncytial virus, are the most frequent cause of significant asthma exacerbations through effects mediated predominantly by TLR3. However, agonists of other nucleic acid sensors, such as TLR7/8 and TLR9 agonists, may inhibit allergic inflammation and reduce clinical manifestations of disease. The allergic state can predispose the immune system to both exaggerated responses to viral infections or protection from anti-viral inflammatory responses. T_H2 cytokines appear to alter the epithelium, leading to defective viral clearance or exaggerated responses to viral infections. However, a T_H2 skewed allergic response may be protective against a T_H1-dependent inflammatory anti-viral response. This review briefly introduces the receptors involved in nucleic acid sensing, addresses mechanisms by which nucleic acid sensing and allergic responses can counteract one another, and discusses the strategies in experimental settings, both in animal and human studies, to harness the nucleic acid sensing machinery for the intervention of allergic disorders.

Simulation of Stimulation: Cytokine Dosage and Cell Cycle Crosstalk Driving Timing-Dependent T Cell Differentiation

Triggering an appropriate protective response against invading agents is crucial to the effectiveness of human innate and adaptive immunity. Pathogen recognition and elimination requires integration of a myriad of signals from many different immune cells. For example, T cell functioning is not qualitatively, but quantitatively determined by cellular and humoral signals. Tipping the balance of signals, such that one of these is favored or gains advantage on another one, may impact the plasticity of T cells. This may lead to switching their phenotypes and, ultimately, modulating the balance between proliferating and memory T cells to sustain an appropriate immune response. We hypothesize that, similar to other intracellular processes such as the cell cycle, the process of T cell differentiation is the result of: (i) pleiotropy (pattern) and (ii) magnitude (dosage/concentration) of input signals, as well as (iii) their timing and duration. That is, a flexible, yet robust immune response upon recognition of the pathogen may result from the integration of signals at the right dosage and timing. To investigate and understand how system's properties such as T cell plasticity and T cell-mediated robust response arise from the interplay between these signals, the use of experimental toolboxes that modulate immune proteins may be explored. Currently available methodologies to engineer T cells and a recently devised strategy to measure protein dosage may be employed to precisely determine, for example, the expression of transcription factors responsible for T cell differentiation into various subtypes. Thus, the immune response may be systematically investigated quantitatively. Here, we provide a perspective of how pattern, dosage and timing of specific signals, called interleukins, may influence T cell activation and differentiation during the course of the immune response. We further propose that interleukins alone cannot explain the phenotype variability observed in T cells. Specifically, we provide evidence that the dosage of intercellular components of both the immune system and the cell cycle regulating cell proliferation may contribute to T cell activation, differentiation, as well as T cell memory formation and maintenance. Altogether, we envision that a qualitative (pattern) and quantitative (dosage) crosstalk between the extracellular milieu and intracellular proteins leads to T cell plasticity and robustness. The understanding of this complex interplay is crucial to predict and prevent scenarios where tipping the balance of signals may be compromised, such as in autoimmunity.