Discovery of CD80 and CD86 as recent activation markers on regulatory T cells by protein-RNA single-cell analysis

Single cell transcriptomics reveals the cellular heterogeneity of keloids and the mechanism of their aggressiveness

Keloid is a dermatofibrotic disease known for its aggressive nature and characterized by pathological scarring, which often leads to disfigurement and frequent recurrences. Effective therapies for keloids are still limited, presumably due to the inadequate comprehension of their aggressive mechanisms. In our study, we examined the unique scenario where both keloid and non-aggressive pathological scar originate from the same patient, providing a rare opportunity to explore the aggressive mechanisms of keloids through single-cell RNA sequencing. We found that the dominant fibroblast subgroup in keloids is mechanoresponsive group, which showed enhanced mechanotransduction and migration. This mechanoresponsive fibroblast subgroup is likely to be the key cell population and confer aggressive growth of keloids. The results also indicate that the endothelial cells and keratinocytes in keloid involve in endothelial-mesenchymal and epithelial-mesenchymal transitions. This study demonstrated the mechanoresponsive fibroblasts and multiple cellular mesenchymal processes could pave the way for further investigations into the keloid aggressiveness.

Identification of a novel immune-related gene signature by single-cell and bulk sequencing for the prediction of the immune landscape and prognosis of breast cancer

BACKGROUND

As a common cause of cancer-related deaths in women, BRCA (breast cancer) shows complexity and requires precise biomarkers and treatment methods. This study delves into the molecular makeup of BRCA, focusing on immune profiles, molecular subtypes, gene expression and single-cell analysis.

METHODS

XCell was used to assess immune infiltration based on TCGA (the Cancer Genome Atlas) data and the clustering analysis was made. Differentially expressed genes were examined in distinct clusters, and the WGCNA (weighted correlation network analysis) was made to establish co-expression networks. The prognostic models were developed by Cox and LASSO-Cox regression. The clustering analysis, GSEA (Gene set enrichment analysis), GSVA (gene set variation analysis) and communication analysis of the single-cell dataset GSE161529 were performed to investigate the functional relevance. Real-time polymerase chain reaction (RT-PCR) was employed for evaluating gene expression.

RESULTS

The results revealed significant differences in immune cell infiltration between two clusters (C1 and C2). C2 had poorer survival outcomes, which was associated with higher expression of immune checkpoints PD1 and PD-L1. The gene modules identified via WGCNA were correlated with the immune-based subtypes. Then, a prognostic model comprising seven genes (ACSL1, ABCB5, XG, ADH4, OPN4, NPR3, NLGN1) was used to divide patients into high- and low-risk subgroups. The high-risk group had worse prognosis and higher scores of TIDE (Tumor Immune Dysfunction and Exclusion). The single-cell analysis depicted the immune landscape. Macrophages and endothelial cells exhibited higher AUCell scores. In cellular communication analysis, notably significant ligand-receptor interactions of HLA-DRA-> CD4 and TNFSF13B-> HLA-DPB1 were observed. The proportion of endothelial cells was correlated with risk scores. Finally, RT-PCR results illustrated the expression of seven genes in BRCA specimens.

CONCLUSION

The integrative analysis provides new insights into molecular complexities of BRCA. Immune profiles and gene signatures hold potential for improving stratification of BRCA patients and guiding the development of personalized immunotherapy strategies.

Glut3 promotes cellular O-GlcNAcylation as a distinctive tumor-supportive feature in Treg cells

Regulatory T cells (Tregs) establish dominant immune tolerance but obstruct tumor immune surveillance, warranting context-specific mechanistic insights into the functions of tumor-infiltrating Tregs (TIL-Tregs). We show that enhanced posttranslational O-linked N-acetylglucosamine modification (O-GlcNAcylation) of cellular factors is a molecular feature that promotes a tumor-specific gene expression signature and distinguishes TIL-Tregs from their systemic counterparts. We found that altered glucose utilization through the glucose transporter Glut3 is a major facilitator of this process. Treg-specific deletion of Glut3 abrogates tumor immune tolerance, while steady-state immune homeostasis remains largely unaffected in mice. Furthermore, by employing mouse tumor models and human clinical data, we identified the NF-κB subunit c-Rel as one such factor that, through Glut3-dependent O-GlcNAcylation, functionally orchestrates gene expression in Tregs at tumor sites. Together, these results not only identify immunometabolic alterations and molecular events contributing to fundamental aspects of Treg biology, specifically at tumor sites but also reveal tumor-specific cellular properties that can aid in the development of Treg-targeted cancer immunotherapies.

Temporal Alterations in CD8+ T Cells During the Progression From Stage 1 to Stage 3 Type 1 Diabetes

CD8+ T cells are perceived to play a major role in the pathogenesis of type 1 diabetes (T1D). In this study, we characterized the function and phenotype of circulating CD8+ memory T cells in samples from individuals at different stages of T1D progression using flow cytometry and single-cell multiomics. We observed two distinct CD8+ T-cell signatures during progression of T1D within the highly differentiated CD27-CD8+ memory T-cell subset. A proinflammatory signature, with an increased frequency of IFN-γ+TNF-α+ CD27-CD8+ memory T cells, was observed in children with newly diagnosed T1D (stage 3) and correlated with the level of dysglycemia at diagnosis. In contrast, a coinhibitory signature, with an increased frequency of KLRG1+TIGIT+ CD27-CD8+ memory T cells, was observed in islet autoantibody-positive children who later progressed to T1D (stage 1). No alterations within CD27-CD8+ memory T cells were observed in adults with established T1D or in children during the initial seroconversion to islet autoantibody positivity. Single-cell multiomics analyses suggested that CD27-CD8+ T cells expressing the IFNG+TNF+ proinflammatory signature may be distinct from those expressing the KLRG1+TIGIT+ coinhibitory signature at the single-cell level. Collectively, our findings suggest that distinct blood CD8+ T-cell signatures could be employed as potential biomarkers of T1D progression.

ARTICLE HIGHLIGHTS

Single-Cell RNA Sequencing and Combinatorial Approaches for Understanding Heart Biology and Disease

By directly measuring multiple molecular features in hundreds to millions of single cells, single-cell techniques allow for comprehensive characterization of the diversity of cells in the heart. These single-cell transcriptome and multi-omic studies are transforming our understanding of heart development and disease. Compared with single-dimensional inspections, the combination of transcriptomes with spatial dimensions and other omics can provide a comprehensive understanding of single-cell functions, microenvironment, dynamic processes, and their interrelationships. In this review, we will introduce the latest advances in cardiac health and disease at single-cell resolution; single-cell detection methods that can be used for transcriptome, genome, epigenome, and proteome analysis; single-cell multi-omics; as well as their future application prospects.

Single-cell sequencing to multi-omics: technologies and applications

Cells, as the fundamental units of life, contain multidimensional spatiotemporal information. Single-cell RNA sequencing (scRNA-seq) is revolutionizing biomedical science by analyzing cellular state and intercellular heterogeneity. Undoubtedly, single-cell transcriptomics has emerged as one of the most vibrant research fields today. With the optimization and innovation of single-cell sequencing technologies, the intricate multidimensional details concealed within cells are gradually unveiled. The combination of scRNA-seq and other multi-omics is at the forefront of the single-cell field. This involves simultaneously measuring various omics data within individual cells, expanding our understanding across a broader spectrum of dimensions. Single-cell multi-omics precisely captures the multidimensional aspects of single-cell transcriptomes, immune repertoire, spatial information, temporal information, epitopes, and other omics in diverse spatiotemporal contexts. In addition to depicting the cell atlas of normal or diseased tissues, it also provides a cornerstone for studying cell differentiation and development patterns, disease heterogeneity, drug resistance mechanisms, and treatment strategies. Herein, we review traditional single-cell sequencing technologies and outline the latest advancements in single-cell multi-omics. We summarize the current status and challenges of applying single-cell multi-omics technologies to biological research and clinical applications. Finally, we discuss the limitations and challenges of single-cell multi-omics and potential strategies to address them.

Aberrant innate immune profile associated with COVID-19 mortality in Pretoria, South Africa

The African continent reported the least number of COVID-19 cases and deaths of all the continents, although the exact reasons for this are still unclear. In addition, little is known about the immunological profiles associated with COVID-19 mortality in Africa. The present study compared clinical and immunological parameters, as well as treatment outcomes in patients admitted with COVID-19 in Pretoria, South Africa, to determine if these parameters correlated with mortality in this population. The in-hospital mortality rate for the cohort was 15.79%. The mortality rate in people living with HIV (PLWH) was 10.81% and 17.16% in people without HIV (p = 0.395). No differences in age (p = 0.099), gender (p = 0.127) or comorbidities were found between deceased patients and those who survived. All four of the PLWH who died had a CD4+ T-cell count <200 cells/mm3, a significantly higher HIV viral load than those who survived (p = 0.009), and none were receiving antiretroviral therapy. Seven of 174 (4%) patients had evidence of auto-antibodies neutralizing Type 1 interferons (IFNs). Two of the them died, and their presence was significantly associated with mortality (p = 0.042). In the adjusted model, the only clinical parameters associated with mortality were: higher fraction of inspired oxygen (FiO2) (OR: 3.308, p = 0.011) indicating a greater need for oxygen, high creatinine (OR: 4.424, p = 0.001) and lower platelet counts (OR: 0.203, p = 0.009), possibly secondary to immunothrombosis. Overall, expression of the co-receptor CD86 (p = 0.021) on monocytes and percentages of CD8+ effector memory 2 T-cells (OR: 0.45, p = 0.027) was lower in deceased patients. Decreased CD86 expression impairs the development and survival of effector memory T-cells. Deceased patients had higher concentrations of RANTES (p = 0.003), eotaxin (p = 0.003) and interleukin (IL)-8 (p < 0.001), all involved in the activation and recruitment of innate immune cells. They also had lower concentrations of transforming growth factor (TGF)-β1 (p = 0.40), indicating an impaired anti-inflammatory response. The immunological profile associated with COVID-19 mortality in South Africa points to the role of aberrate innate immune responses.

Anti-allergic effect of vitamin C through inhibiting degranulation and regulating TH1/TH2 cell polarization

BACKGROUND

Food allergy has become a global public health problem. This study aimed to explore the possible anti-allergic effect of vitamin C (VC). A rat basophilic leukemia (RBL)-2H3 cell degranulation model was used to assess the effect of VC on degranulation in vitro, and an ovalbumin (OVA)-induced BALB/c mouse allergy model was used to assess the anti-allergy effect of VC in vivo.

RESULTS

In vitro, VC significantly attenuated the release of β-hexosaminidase, tryptase and histamine, and also reduced cytokine production (interleukins 4 and 6, tumor necrosis factor α) significantly (P < 0.05), with the inhibitory effect demonstrating a positive correlation with VC dose. In vivo, compared with the OVA group, the levels of serum immunoglobulins E and G1 of the VC low-dose (VCL) group (50 mg kg-1) and high-dose (VCH) group (200 mg·kg-1) were significantly reduced (P < 0.05). Furthermore, the plasma histamine level was also significantly decreased (P < 0.05). Moreover, TH2 cell polarization in mice of the VCL and VCH groups was significantly inhibited (P < 0.05), promoting the TH1/TH2 cell polarization balance. Additionally, VC treatment enhanced the expression of CD80 (P < 0.05) in spleen and small intestine tissues, while significantly inhibiting the expression of CD86 (P < 0.05); notably, high-dose VC treatment was more effective.

CONCLUSION

VC exerted an anti-allergic effect through inhibiting degranulation and regulating TH1/TH2 cell polarization balance. © 2024 Society of Chemical Industry.

The Immunomodulatory Function of Assembled Composite Nanopolypeptide Containing Bursal-Derived BP7 (CNPB7) in Promoting the Mucosal Immune Response within Poultry Immunization

Mucosal immunity is the main defense line against respiratory disease pathogens. Newcastle disease and avian infectious bronchitis are common respiratory diseases in poultry. However, the mucosal immune response is not sufficiently activated and thus fails to achieve the ideal immune protection. Therefore, it is important to develop a suitable mucosal immune adjuvant to enhance the immune response of live vaccines. Here, the bursal-derived peptide BP7, β-glucan, and hyaluronic acid were selected as the adjuvant to be assembled into the composite nanopolypeptide adjuvant (CNPB7) with ultrasonic dispersion technology. The results showed that after optimizing assembly conditions, the optimal average particle size of nanoparticle CNPB7 was 514.9 nm and PDI was 0.298. To evaluate the non-specific immune responses of nanoparticle CNPB7, the chickens were immunized only with nanoparticle CNPB7. It was confirmed that nanoparticle CNPB7 enhanced the expression of CD3, CD4, CD80, and CD86 factors in the spleen lymphocyte from the chicken immunized with nanoparticle CNPB7. To investigate the mucosal immune response of nanoparticle CNPB7, the chickens were orally immunized with Newcastle disease virus (NDV)-infectious bronchitis virus (IBV) dual vaccines and CNPB7. The results proved that the levels of immunoglobulin SIgA, IL-4, IFN-γ, and IL-13 in the mucus samples from the respiratory and digestive tract in chicken immunized with nanoparticle CNPB7 and vaccines were significantly increased, compared to that of vaccine control. Finally, it was observed that nanoparticle CNPB7 promoted specific increased antibody productions against NDV and IBV in the immunized chicken. These results proved that the assembled nanoparticle CNPB7 could enhance the vaccination efficacy in chicken, which provided the experimental basis for the development of new adjuvants, and offered technical support for preventing virus transmission of avian diseases.

Complex Role of Regulatory T Cells (Tregs) in the Tumor Microenvironment: Their Molecular Mechanisms and Bidirectional Effects on Cancer Progression

Regulatory T cells (Tregs) possess unique immunosuppressive activity among CD4-positive T cells. Tregs are ubiquitously present in mammals and function to calm excessive immune responses, thereby suppressing allergies or autoimmune diseases. On the other hand, due to their immunosuppressive function, Tregs are thought to promote cancer progression. The tumor microenvironment (TME) is a multicellular system composed of many cell types, including tumor cells, infiltrating immune cells, and cancer-associated fibroblasts (CAFs). Within this environment, Tregs are recruited by chemokines and metabolic factors and impede effective anti-tumor responses. However, in some cases, their presence can also improve patient's survival rates. Their functional consequences may vary across tumor types, locations, and stages. An in-depth understanding of the precise roles and mechanisms of actions of Treg is crucial for developing effective treatments, emphasizing the need for further investigation and validation. This review aims to provide a comprehensive overview of the complex and multifaceted roles of Tregs within the TME, elucidating cellular communications, signaling pathways, and their impacts on tumor progression and highlighting their potential anti-tumor mechanisms through interactions with functional molecules.

New expression of PD-L1 on activated CD4+ T cells opens up new opportunities for cell interactions and signaling

Surface expression of programmed death-ligand 1 (PD-L1) is mainly observed on antigen presenting cells (APC) such as monocytes or dendritic cells (DCs). Our results showing a high expression of PD-L1 on human naïve CD4+ effector T-cells (TEFFs) and CD4+ regulatory T cells (TREGs) after activation with human DCs, allow us to propose a new role for PD-L1 and its ligands and their potential impact on new signaling pathways. Indeed, expression of PD-L1 on activated CD4+T cells could allow cis interaction with its ligands such as PD-1 and CD80, thus disrupting interactions with other signaling receptors, such as cytotoxic T-lymphocyte antigen-4 (CTLA-4) or CD28, which interact with CD80. The ability to compete with hypothetical configuration modifications that may cause a change in affinity/avidity for the trans and cis interactions between these proteins expressed on T cells and/or DCs is discussed. As the study of cancer is strongly influenced by the role of the PD-L1/PD-1 pathway and CD4+T cells, new interactions, cis and/or trans, between TEFFs, TREGs and tumor cells are also proposed. The presence of PD-L1 on activated CD4+ T cells could influence the quality of the cytotoxic T lymphocyte response during priming to provide other help signals.

Graphene Oxide (GO)-Based Bioink with Enhanced 3D Printability and Mechanical Properties for Tissue Engineering Applications

Currently, a major challenge in material engineering is to develop a cell-safe biomaterial with significant utility in processing technology such as 3D bioprinting. The main goal of this work was to optimize the composition of a new graphene oxide (GO)-based bioink containing additional extracellular matrix (ECM) with unique properties that may find application in 3D bioprinting of biomimetic scaffolds. The experimental work evaluated functional properties such as viscosity and complex modulus, printability, mechanical strength, elasticity, degradation and absorbability, as well as biological properties such as cytotoxicity and cell response after exposure to a biomaterial. The findings demonstrated that the inclusion of GO had no substantial impact on the rheological properties and printability, but it did enhance the mechanical properties. This enhancement is crucial for the advancement of 3D scaffolds that are resilient to deformation and promote their utilization in tissue engineering investigations. Furthermore, GO-based hydrogels exhibited much greater swelling, absorbability and degradation compared to non-GO-based bioink. Additionally, these biomaterials showed lower cytotoxicity. Due to its properties, it is recommended to use bioink containing GO for bioprinting functional tissue models with the vascular system, e.g., for testing drugs or hard tissue models.

Role of Treg cell subsets in cardiovascular disease pathogenesis and potential therapeutic targets

In the genesis and progression of cardiovascular diseases involving both innate and adaptive immune responses, inflammation plays a pivotal and dual role. Studies in experimental animals indicate that certain immune responses are protective, while others exacerbate the disease. T-helper (Th) 1 cell immune responses are recognized as key drivers of inflammatory progression in cardiovascular diseases. Consequently, the CD4+CD25+FOXP3+ regulatory T cells (Tregs) are gaining increasing attention for their roles in inflammation and immune regulation. Given the critical role of Tregs in maintaining immune-inflammatory balance and homeostasis, abnormalities in their generation or function might lead to aberrant immune responses, thereby initiating pathological changes. Numerous preclinical studies and clinical trials have unveiled the central role of Tregs in cardiovascular diseases, such as atherosclerosis. Here, we review the roles and mechanisms of Treg subsets in cardiovascular conditions like atherosclerosis, hypertension, myocardial infarction and remodeling, myocarditis, dilated cardiomyopathy, and heart failure. While the precise molecular mechanisms of Tregs in cardiac protection remain elusive, therapeutic strategies targeting Tregs present a promising new direction for the prevention and treatment of cardiovascular diseases.

Associating growth factor secretions and transcriptomes of single cells in nanovials using SEC-seq

Cells secrete numerous bioactive molecules that are essential for the function of healthy organisms. However, scalable methods are needed to link individual cell secretions to their transcriptional state over time. Here, by developing and using secretion-encoded single-cell sequencing (SEC-seq), which exploits hydrogel particles with subnanolitre cavities (nanovials) to capture individual cells and their secretions, we simultaneously measured the secretion of vascular endothelial growth factor A (VEGF-A) and the transcriptome for thousands of individual mesenchymal stromal cells. Our data indicate that VEGF-A secretion is heterogeneous across the cell population and is poorly correlated with the VEGFA transcript level. The highest VEGF-A secretion occurs in a subpopulation of mesenchymal stromal cells characterized by a unique gene expression signature comprising a surface marker, interleukin-13 receptor subunit alpha 2 (IL13RA2), which allowed the enrichment of this subpopulation. SEC-seq enables the identification of gene signatures linked to specific secretory states, facilitating mechanistic studies, the isolation of secretory subpopulations and the development of means to modulate cellular secretion.

Nanopore DNA sequencing technologies and their applications towards single-molecule proteomics

Sequencing of nucleic acids with nanopores has emerged as a powerful tool offering rapid readout, high accuracy, low cost and portability. This label-free method for sequencing at the single-molecule level is an achievement on its own. However, nanopores also show promise for the technologically even more challenging sequencing of polypeptides, something that could considerably benefit biological discovery, clinical diagnostics and homeland security, as current techniques lack portability and speed. Here we survey the biochemical innovations underpinning commercial and academic nanopore DNA/RNA sequencing techniques, and explore how these advances can fuel developments in future protein sequencing with nanopores.

Established and emerging techniques for the study of microglia: visualization, depletion, and fate mapping

The central nervous system (CNS) is an essential hub for neuronal communication. As a major component of the CNS, glial cells are vital in the maintenance and regulation of neuronal network dynamics. Research on microglia, the resident innate immune cells of the CNS, has advanced considerably in recent years, and our understanding of their diverse functions continues to grow. Microglia play critical roles in the formation and regulation of neuronal synapses, myelination, responses to injury, neurogenesis, inflammation, and many other physiological processes. In parallel with advances in microglial biology, cutting-edge techniques for the characterization of microglial properties have emerged with increasing depth and precision. Labeling tools and reporter models are important for the study of microglial morphology, ultrastructure, and dynamics, but also for microglial isolation, which is required to glean key phenotypic information through single-cell transcriptomics and other emerging approaches. Strategies for selective microglial depletion and modulation can provide novel insights into microglia-targeted treatment strategies in models of neuropsychiatric and neurodegenerative conditions, cancer, and autoimmunity. Finally, fate mapping has emerged as an important tool to answer fundamental questions about microglial biology, including their origin, migration, and proliferation throughout the lifetime of an organism. This review aims to provide a comprehensive discussion of these established and emerging techniques, with applications to the study of microglia in development, homeostasis, and CNS pathologies.

Single-cell insights into immune dysregulation in rheumatoid arthritis flare versus drug-free remission

Immune-mediated inflammatory diseases (IMIDs) are typically characterised by relapsing and remitting flares of inflammation. However, the unpredictability of disease flares impedes their study. Addressing this critical knowledge gap, we use the experimental medicine approach of immunomodulatory drug withdrawal in rheumatoid arthritis (RA) remission to synchronise flare processes allowing detailed characterisation. Exploratory mass cytometry analyses reveal three circulating cellular subsets heralding the onset of arthritis flare - CD45RO+PD1hi CD4+ and CD8+ T cells, and CD27+CD86+CD21- B cells - further characterised by single-cell sequencing. Distinct lymphocyte subsets including cytotoxic and exhausted CD4+ memory T cells, memory CD8+CXCR5+ T cells, and IGHA1+ plasma cells are primed for activation in flare patients. Regulatory memory CD4+ T cells (Treg cells) increase at flare onset, but with dysfunctional regulatory marker expression compared to drug-free remission. Significant clonal expansion is observed in T cells, but not B cells, after drug cessation; this is widespread throughout memory CD8+ T cell subsets but limited to the granzyme-expressing cytotoxic subset within CD4+ memory T cells. Based on our observations, we suggest a model of immune dysregulation for understanding RA flare, with potential for further translational research towards novel avenues for its treatment and prevention.

Beyond FOXP3: a 20-year journey unravelling human regulatory T-cell heterogeneity

The initial idea of a distinct group of T-cells responsible for suppressing immune responses was first postulated half a century ago. However, it is only in the last three decades that we have identified what we now term regulatory T-cells (Tregs), and subsequently elucidated and crystallized our understanding of them. Human Tregs have emerged as essential to immune tolerance and the prevention of autoimmune diseases and are typically contemporaneously characterized by their CD3+CD4+CD25high CD127lowFOXP3+ phenotype. It is important to note that FOXP3+ Tregs exhibit substantial diversity in their origin, phenotypic characteristics, and function. Identifying reliable markers is crucial to the accurate identification, quantification, and assessment of Tregs in health and disease, as well as the enrichment and expansion of viable cells for adoptive cell therapy. In our comprehensive review, we address the contributions of various markers identified in the last two decades since the master transcriptional factor FOXP3 was identified in establishing and enriching purity, lineage stability, tissue homing and suppressive proficiency in CD4+ Tregs. Additionally, our review delves into recent breakthroughs in innovative Treg-based therapies, underscoring the significance of distinct markers in their therapeutic utilization. Understanding Treg subsets holds the key to effectively harnessing human Tregs for immunotherapeutic approaches.

Vitro UPLC analysis and mass method identification, and in vivo or cellular immune anti-inflammatory function of Sanhuang Xiexin Decoction (SHXD)

ETHNOPHARMACOLOGICAL RELEVANCE

Sanhuang Xiexin Decoction (SHXD), consisting of Coptis chinensis Franch., Scutellaria baicalensis Georgi and Rheum palmatum L., is traditionally used for relieving fever, purging fire for removing toxins, eliminating phlegm and haemostasis, eliminating the wetness-evil from the upper warmer, clearing away the heat-evil and expelling superficial evils. Each of the three herbs contained in SHXD has been indicated to have anti-inflammatory effects in vivo, but its effects on rat NK-cell phenotypes remain unexplored, and the comprehensive mechanism of this compound SHXD in curing the inflammation induced by lipopolysaccharides (LPS) remains to be revealed.

AIM OF THE STUDY

The study aim was to assess the effect of SHXD on LPS-induced fever and inflammation in a rat model, reduce NLRP3 activation in NK cells expressing specific cell phenotype antibodies and determine the therapeutic value of this approach in vivo.

MATERIALS AND METHODS

SHXD extract was prepared and analysed by the developed ultra-performance liquid chromatography (UPLC) method for the simultaneous detection of 14 compounds. The main peaks were firstly identified on an Orbitrap via high resolution tandem mass spectrometry (MS). Then, the extract was used in the rat model of LPS-induced inflammation and fever for pharmacologically study the effects of drug treatment. Peripheral blood lymphocyte cells were isolated from the animals, including those subjected to the SHXD extract treatment, and the cell phenotype was determined prior to cell culture and after treating the cell cultures with the extract. The phenotypes of cells harvested using CD3, CD4, CD8a, CD81, CD161 and CD86 antibodies were used to verify the enhanced memory of the peripheral blood lymphocytes cells (PBMC) that were induced into nature killer (NK) cells.

RESULTS

The SHXD extract was prepared, analysed and identified via quality control equipment and was observed to have pharmacological effects that reduced NLRP3 activation and fever in rats. The production of NK cells and peripheral blood lymphocytes was induced by the SHXD extract, which manifested as increased levels of CD4+, CD8a+, CD81+, CD161+ and CD86+ cells. The levels of CD3+ cells were significantly different between the model group and the drug-treated or control groups (p < 0.01) with dose independence, while the levels of CD4+ cells were not significantly different between the drug-treated and control groups, with a trend towards lower levels in the model group with dose independence. The levels of CD4+ cells was significantly different between the drug-treated group and the model groups with dose independence (p < 0.05). The levels of CD86+ cells were not significantly different between the drug-treated group and the model and control groups. The levels of CD8a + cells was significantly different between the model group and the drug and control groups (p < 0.05, dose 2.0 μg/ml), with higher levels in the drug-treated group. The levels of CD3+, CD4+, CD8a + cells in the drug treated group have dose dependence with SHXD.

CONCLUSIONS

This experiment revealed that SHXD reduced NLRP3 activation in the blood of LPS-treated rats, which occurred through the activation of NK cells that expressed CD3, CD8a and CD161. SHXD may possess anti-inflammatory effect via activacting the one of major pharmacology effcet of NK cells that expressed CD3, CD8a and CD161 phenotypes expression. This result demonstrates that SHXD may possess ability to enhance the memory of peripheral blood lymphocytes and natural killer cells.

Fingerprint of Circulating Immunocytes as Biomarkers for the Prognosis of Brain Inflammation and Neuronal Injury after Cardiac Arrest

Cardiac arrest is one of the most dangerous health problems in the world. Outcome prognosis is largely based on cerebral performance categories determined by neurological evaluations. Few systemic tests are currently available to predict survival to hospital discharge. Here, we present the results from the preclinical studies of cardiac arrest and resuscitation (CAR) in mice to identify signatures of circulating immune cells as blood-derived biomarkers to predict outcomes after CAR. Two flow cytometry panels for circulating blood lymphocytes and myeloid-derived cells, respectively, were designed to correlate with neuroinflammation and neuronal and dendritic losses in the selectively vulnerable regions of bilateral hippocampi. We found that CD4+CD25+ regulatory T cells, CD11b+CD11c- and CD11b+Ly6C+Ly6G+ myeloid-derived cells, and cells positive for the costimulatory molecules CD80 and CD86 in the blood were correlated with activation of microglia and astrocytosis, and CD4+CD25+ T cells are additionally correlated with neuronal and dendritic losses. A fingerprint pattern of blood T cells and monocytes is devised as a diagnostic tool to predict CAR outcomes. Blood tests aimed at identifying these immunocyte patterns in cardiac arrest patients will guide future clinical trials to establish better prognostication tools to avoid unnecessary early withdrawal from life-sustaining treatment.

Killer instincts: natural killer cells as multifactorial cancer immunotherapy

Natural killer (NK) cells integrate heterogeneous signals for activation and inhibition using germline-encoded receptors. These receptors are stochastically co-expressed, and their concurrent engagement and signaling can adjust the sensitivity of individual cells to putative targets. Against cancers, which mutate and evolve under therapeutic and immunologic pressure, the diversity for recognition provided by NK cells may be key to comprehensive cancer control. NK cells are already being trialled as adoptive cell therapy and targets for immunotherapeutic agents. However, strategies to leverage their naturally occurring diversity and agility have not yet been developed. In this review, we discuss the receptors and signaling pathways through which signals for activation or inhibition are generated in NK cells, focusing on their roles in cancer and potential as targets for immunotherapies. Finally, we consider the impacts of receptor co-expression and the potential to engage multiple pathways of NK cell reactivity to maximize the scope and strength of antitumor activities.

Memory regulatory T cells in pregnancy

Pregnancy requires the process of maternal immune tolerance to semi-allogeneic embryos. In contrast, an overreactive maternal immune system to embryo-specific antigens is likely to result in the rejection of embryos while damaging the invading placenta, such that the likelihood of adverse pregnancy outcomes can be increased. Regulatory T cells (Tregs) are capable of suppressing excessive immune responses and regulating immune homeostasis. When stimulating Tregs, specific antigens will differentiate into memory Tregs with long-term survival and rapid and powerful immune regulatory ability. Immunomodulatory effects mediated by memory Tregs at the maternal-fetal interface take on critical significance in a successful pregnancy. The impaired function of memory Tregs shows a correlation with various pregnancy complications (e.g., preeclampsia, gestational diabetes mellitus, and recurrent pregnancy losses). However, the differentiation process and characteristics of memory Tregs, especially their role in pregnancy, remain unclear. In this study, a review is presented in terms of memory Tregs differentiation and activation, the characteristics of memory Tregs and their role in pregnancy, and the correlation between memory Tregs and pregnancy complications. Furthermore, several potential therapeutic methods are investigated to restore the function of memory Tregs in accordance with immunopathologies arising from memory Tregs abnormalities and provide novel targets for diagnosing and treating pregnancy-associated diseases.

Tumour-associated macrophages: versatile players in the tumour microenvironment

Tumour-Associated Macrophages (TAMs) are one of the pivotal components of the tumour microenvironment. Their roles in the cancer immunity are complicated, both pro-tumour and anti-cancer activities are reported, including not only angiogenesis, extracellular matrix remodeling, immunosuppression, drug resistance but also phagocytosis and tumour regression. Interestingly, TAMs are highly dynamic and versatile in solid tumours. They show anti-cancer or pro-tumour activities, and interplay between the tumour microenvironment and cancer stem cells and under specific conditions. In addition to the classic M1/M2 phenotypes, a number of novel dedifferentiation phenomena of TAMs are discovered due to the advanced single-cell technology, e.g., macrophage-myofibroblast transition (MMT) and macrophage-neuron transition (MNT). More importantly, emerging information demonstrated the potential of TAMs on cancer immunotherapy, suggesting by the therapeutic efficiency of the checkpoint inhibitors and chimeric antigen receptor engineered cells based on macrophages. Here, we summarized the latest discoveries of TAMs from basic and translational research and discussed their clinical relevance and therapeutic potential for solid cancers.

Clinical effect of aerobic exercise training in chronic obstructive pulmonary disease: A retrospective study

Aerobic exercise training is a kind of pulmonary rehabilitation for lung diseases. This was a retrospective study to assess the efficacy of aerobic exercise training in chronic obstructive pulmonary disease (COPD) at a stable stage. A total of one hundred and fifty-six stable COPD patients who had accepted self-education only or self-education combined with an aerobic exercise training between January 2017 to January 2019 were reviewed retrospectively. A total of 79 patients who had received self-education combined with an aerobic exercise training schedule comprised the aerobic exercise training group (AET group) and 77 patients who had received self-education only were regarded as the education group (EDU group). The acute incidence rate in AET group was 7.6% better than that in EDU group 20.7% (P < .05). The AET group patients expressed higher levels of 6 minutes walking distance (6MWD) (P < .05) and better evaluations of both lung function (P < .05) and T lymphocyte immune response (P < .05), as well as significantly decreased chronic obstructive pulmonary disease assessment test (CAT) scores and modified British medical research council (mMRC) grades (P < .05). Patients in EDU group did not report any changes in any of these characteristics. The aerobic exercise training intervention contributed to an increasing in 6MWD and decrease in CAT scores and mMRC grades, as well as improving the T lymphocyte immune response in stable COPD patients.

Molecular insights of a CBP/β-catenin-signaling inhibitor on nonalcoholic steatohepatitis-induced liver fibrosis and disorder

Nonalcoholic steatohepatitis (NASH) is a progressive fibrotic disease associated with an increased risk of developing hepatocellular carcinoma; at present, no efficient therapeutic strategy has been established. Herein, we examined the efficacy of PRI-724, a potent inhibitor of CBP/β-catenin signaling, for treating NASH-related liver fibrosis and disorder and characterized its mechanism. Choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD)-fed mice exhibited NASH-induced liver fibrosis that is characterized by steatosis, lobular inflammation, hepatocellular injury and collagen fibrils. To examine the therapeutic effect, CDAHFD-fed mice were administered PRI-724. Serum levels of ALT and pro-fibrotic molecule, i.e. Mac-2 bp, alpha smooth muscle actin, type I and type III collagens, decreased significantly. mRNA levels of the matrix metalloproteinases Mmp8 and Mmp9 in the liver were significantly increased, and increases in the abundance of MMP9-producing neutrophils and macrophages were observed. Marco+Mmp9+Cd68+ Kupffer cells were only observed in the livers of mice treated with PRI-724, and Mmp9 expression in Marco+Cd68+ Kupffer cells increased 4.3-fold. Moreover, hepatic expression of the lipid metabolism regulator, pyruvate dehydrogenase kinase 4 and liver lipid droplets also decreased significantly. PRI-724-treated NASH mice not only recovered from NASH-related liver fibrosis through the effect of PRI-724 down-regulating the expression of pro-fibrotic genes and up-regulating the expression of anti-fibrotic genes, but they also recovered from NASH-induced liver disorder. PRI-724, a selective CBP/β-catenin inhibitor, thus shows a potent therapeutic effect for NASH-related liver fibrosis and for decreasing adipose tissue in the liver.

Inflammation across tissues: can shared cell biology help design smarter trials?

Immune-mediated inflammatory diseases (IMIDs) are responsible for substantial global disease burden and associated health-care costs. Traditional models of research and service delivery silo their management within organ-based medical disciplines. Very often patients with disease in one organ have comorbid involvement in another, suggesting shared pathogenic pathways. Moreover, different IMIDs are often treated with the same drugs (including glucocorticoids, immunoregulators and biologics). Unlocking the cellular basis of these diseases remains a major challenge, leading us to ask why, if these diseases have so much in common, they are not investigated in a common manner. A tissue-based, cellular understanding of inflammation might pave the way for cross-disease, cross-discipline basket trials (testing one drug across two or more diseases) to reduce the risk of failure of early-phase drug development in IMIDs. This new approach will enable rapid assessment of the efficacy of new therapeutic agents in cross-disease translational research in humans.

CTLA4 depletes T cell endogenous and trogocytosed B7 ligands via cis-endocytosis

CD28 and CTLA4 are T cell coreceptors that competitively engage B7 ligands CD80 and CD86 to control adaptive immune responses. While the role of CTLA4 in restraining CD28 costimulatory signaling is well-established, the mechanism has remained unclear. Here, we report that human T cells acquire antigen-presenting-cell (APC)-derived B7 ligands and major histocompatibility complex (MHC) via trogocytosis through CD28:B7 binding. Acquired MHC and B7 enabled T cells to autostimulate, and this process was limited cell-intrinsically by CTLA4, which depletes B7 ligands trogocytosed or endogenously expressed by T cells through cis-endocytosis. Extending this model to the previously proposed extrinsic function of CTLA4 in human regulatory T cells (Treg), we show that blockade of either CD28 or CTLA4 attenuates Treg-mediated depletion of APC B7, indicating that trogocytosis and CTLA4-mediated cis-endocytosis work together to deplete B7 from APCs. Our study establishes CTLA4 as a cell-intrinsic molecular sink that limits B7 availability on the surface of T cells, with implications for CTLA4-targeted therapy.

Curving out a new path: CD28/B7 cis interactions

Important signaling events at the immunological synapse have increasingly been linked to cis interactions between receptors on T cells. In this issue of Immunity, Zhao et al.¹ implicate cis CD28/B7 interactions facilitated by curved membrane invaginations in boosting tumor immunity.

Endocrine side effects of immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) have increasingly been the mainstay of treatment for numerous malignancies. However, due to their association with autoimmunity, ICIs have resulted in a variety of side effects that involve multiple organs including the endocrine system. In this review article, we describe our current understanding of the autoimmune endocrinopathies as a result of the use of ICIs. We will review the epidemiology, pathophysiology, clinical presentation, diagnosis, and management of the most commonly encountered endocrinopathies, including thyroiditis, hypophysitis, Type 1 diabetes, adrenalitis, and central diabetes insipidus.

Dysregulation of immune response in PCOS organ system

Polycystic ovary syndrome (PCOS) is the most common reproductive endocrine disorder affecting women, which can lead to infertility. Infertility, obesity, hirsutism, acne, and irregular menstruation are just a few of the issues that PCOS can be linked to. PCOS has a complicated pathophysiology and a range of clinical symptoms. Chronic low-grade inflammation is one of the features of PCOS. The inflammatory environment involves immune and metabolic disturbances. Numerous organ systems across the body, in addition to the female reproductive system, have been affected by the pathogenic role of immunological dysregulation in PCOS in recent years. Insulin resistance and hyperandrogenism are associated with immune cell dysfunction and cytokine imbalance. More importantly, obesity is also involved in immune dysfunction in PCOS, leading to an inflammatory environment in women with PCOS. Hormone, obesity, and metabolic interactions contribute to the pathogenesis of PCOS. Hormone imbalance may also contribute to the development of autoimmune diseases. The aim of this review is to summarize the pathophysiological role of immune dysregulation in various organ systems of PCOS patients and provide new ideas for systemic treatment of PCOS in the future.

Advanced Delivery Strategies for Immunotherapy in Type I Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) has been defined as an autoimmune disease characterised by immune-mediated destruction of the pancreatic β cells, leading to absolute insulin deficiency and hyperglycaemia. Current research has increasingly focused on immunotherapy based on immunosuppression and regulation to rescue T-cell-mediated β-cell destruction. Although T1DM immunotherapeutic drugs are constantly under clinical and preclinical development, several key challenges remain, including low response rates and difficulty in maintaining therapeutic effects. Advanced drug delivery strategies can effectively harness immunotherapies and improve their potency while reducing their adverse effects. In this review, we briefly introduce the mechanisms of T1DM immunotherapy and focus on the current research status of the integration of the delivery techniques in T1DM immunotherapy. Furthermore, we critically analyse the challenges and future directions of T1DM immunotherapy.

Mettl14 sustains FOXP3 expression to promote the differentiation and functions of induced-regulatory T cells via the mTOR signaling pathway

Induced regulatory T cell (iTregs) can be generated in vitro. Thus, iTregs-based therapeutics are receiving increased attention for their potential to treat autoimmune diseases and prevent transplant rejection. However, iTregs fail to maintain FoxP3 expression and suppressive activity, which limits their clinical application. Increasing lines of evidence suggest that methyltransferase-like 14 (METTL14), a critical component of the m6A writer complex, regulates the stability and function of the Treg cells. However, beyond meeting the epigenetic modification of Treg cells, whether Mettl14 plays a role in the fate determination of iTregs is unclear. Here, we systemically investigated the potential function of METTL14 in iTregs differentiation and regulatory activity. In our study, iTregs were generated from CD4⁺ naïve T cells under iTreg-polarizing conditions, we found that the expression of METTL14 was increased in iTregs compared with CD4⁺ naïve T cells. Subsequently, the expression of METTL14 was knocked down by siRNA-METTL14 interference in CD4⁺ naïve T cells and cultured under iTreg-polarizing conditions. According to the results, Mettl14 deficiency resulted in the disruption of iTregs differentiation evidenced by the limited FoxP3 expression. Meanwhile, inflammatory cytokines such as IFN-γ and IL-17a were upregulated in cultured iTregs. We next determined the functional change in METTL14-deficient iTregs. The results of the colitis development in Rag1^-/- mice and CFSE assays revealed that loss of METTL14 significantly compromised the suppressive function of iTregs in vivo and in vitro. We further checked the altered signaling pathway in METTL14-deficient iTregs. We found that reduced METTL14 leads to activation of the mTOR pathway with increased p-mTOR and p-p70S6K, which are known to modulate the suppressive function of iTregs. In conclusion, our study revealed that Mettl14 plays a critical role in the development and suppressive function of iTregs in vitro and could thus serve as a regulatory element for stabilizing iTregs in cell-based therapy.

Induced regulatory T cells modified by knocking down T-bet in combination with ectopic expression of inhibitory cytokines effectively protect Graft-versus-Host Disease

Induced regulatory T (iT_reg) cells play a vital role in immune tolerance and in controlling chronic inflammation. Generated in the periphery, iT_reg cells are suitable for responding to alloantigens and preventing transplant rejection. Nevertheless, their clinical application has been impeded by the plasticity and instability attributed to the loss of Foxp3 expression, raising concerns that iT_reg may be converted to T_eff cells and even exert a pathogenic effect. Herein, second-generation short hairpin RNAs (shRNAs) loaded with three pairs of small interfering RNAs (siRNAs) were utilized to target the transcription factor T-bet. In addition, two immunosuppressive cytokines, namely transforming growth factor beta (TGF-β) and interleukin-10 (IL-10), were constitutively expressed. This novel engineering strategy allowed the generation of stably-induced iT_reg cells (SI T_reg), which maintained the expression of Foxp3 even in an unfavorable environment and exerted potent immunosuppressive functions in vitro. Furthermore, SI T_reg cells demonstrated an effector transcriptional profile. Finally, SI T_reg showed a significant protective effect against G_VHD-related deaths in a xenotransplantation model. Collectively, these results signify that SI T_reg cells hold great promise for future clinical application and offer a rational therapeutic approach for transplant rejection.

Single-cell proteomics enabled by next-generation sequencing or mass spectrometry

In the last decade, single-cell RNA sequencing routinely performed on large numbers of single cells has greatly advanced our understanding of the underlying heterogeneity of complex biological systems. Technological advances have also enabled protein measurements, further contributing to the elucidation of cell types and states present in complex tissues. Recently, there have been independent advances in mass spectrometric techniques bringing us one step closer to characterizing single-cell proteomes. Here we discuss the challenges of detecting proteins in single cells by both mass spectrometry and sequencing-based methods. We review the state of the art for these techniques and propose that there is a space for technological advancements and complementary approaches that maximize the advantages of both classes of technologies.

The Evolution of Single-Cell RNA Sequencing Technology and Application: Progress and Perspectives

As an emerging sequencing technology, single-cell RNA sequencing (scRNA-Seq) has become a powerful tool for describing cell subpopulation classification and cell heterogeneity by achieving high-throughput and multidimensional analysis of individual cells and circumventing the shortcomings of traditional sequencing for detecting the average transcript level of cell populations. It has been applied to life science and medicine research fields such as tracking dynamic cell differentiation, revealing sensitive effector cells, and key molecular events of diseases. This review focuses on the recent technological innovations in scRNA-Seq, highlighting the latest research results with scRNA-Seq as the core technology in frontier research areas such as embryology, histology, oncology, and immunology. In addition, this review outlines the prospects for its innovative application in traditional Chinese medicine (TCM) research and discusses the key issues currently being addressed by scRNA-Seq and its great potential for exploring disease diagnostic targets and uncovering drug therapeutic targets in combination with multiomics technologies.

Phenotypic and Functional Studies of Human Treg Cell Subpopulations

CD4⁺ regulatory T (Treg) cells play an important role in maintaining immune homeostasis. Although these cells were initially studied as a homogenous cohort, we now know that they have unprecedented underlying heterogeneity. This heterogeneity is reflected in their phenotype and functions. As human Treg subpopulations are very small in numbers, it is necessary to develop novel ways of isolating and manipulating these cell populations. In this chapter, we discuss immunoassays established to this effect.

BD Rhapsody™ Single-Cell Analysis System Workflow: From Sample to Multimodal Single-Cell Sequencing Data

Advancements in single-cell sequencing have revolutionized our understanding of complex biological systems such as the immune system and allowed us to overcome limitations in various disciplines of life science research such as oncology, developmental biology, or neurobiology (Perkel, Nature 595. https://www.nature.com/articles/d41586-021-01994-w , 2021).The BD Rhapsody™ Single-Cell Analysis System enables us to capture multimodal information from thousands of single cells in parallel ("Multiomics") covering mRNA expression levels, protein expression levels, the immune repertoire for T-cell receptors (TCR) and B-cell receptors (BCR), and the identification of antigen-specific T cells and B cells using dCODE Dextramer^® (RiO) from Immudex. The system utilizes microwell-based cartridges that allow to capture a broad range of single cells and an imaging device for sample quality control and workflow quality control (including viability and multiplets). The power of Multiomics relies on simultaneously measuring several aspects of single cells, including gene expression and protein abundance, using next generation sequencing (NGS) as a single readout.Here we describe the complete BD Rhapsody™ Single-Cell Analysis System from the sample preparation including different options for the antibody and/or dCODE Dextramer^® staining through to the data analysis.For updated protocols, guides, and technical bulletins, please visit the BD Scomix page: https://scomix.bd.com/hc/en-us or the BDB webpage: https://www.bdbiosciences.com/en-eu .

Low-dose IL-2 reduces IL-21+ T cell frequency and induces anti-inflammatory gene expression in type 1 diabetes

Despite early clinical successes, the mechanisms of action of low-dose interleukin-2 (LD-IL-2) immunotherapy remain only partly understood. Here we examine the effects of interval administration of low-dose recombinant IL-2 (iLD-IL-2) in type 1 diabetes using high-resolution single-cell multiomics and flow cytometry on longitudinally-collected peripheral blood samples. Our results confirm that iLD-IL-2 selectively expands thymic-derived FOXP3+HELIOS+ regulatory T cells and CD56bright NK cells, and show that the treatment reduces the frequency of IL-21-producing CD4+ T cells and of two innate-like mucosal-associated invariant T and Vγ9Vδ2 CD8+ T cell subsets. The cellular changes induced by iLD-IL-2 associate with an anti-inflammatory gene expression signature, which remains detectable in all T and NK cell subsets analysed one month after treatment. These findings warrant investigations into the potential longer-term clinical benefits of iLD-IL-2 in immunotherapy.

PA-X protein of H9N2 subtype avian influenza virus suppresses the innate immunity of chicken bone marrow-derived dendritic cells

H9N2 subtype avian influenza (AI) is an infectious disease associated with immunosuppression in poultry. Here, the regulation function of PA-X protein was determined on the host innate immune response of H9N2-infected chicken bone marrow-derived DCs (chBM-DCs). Based on 2 mutated viruses expressing PA-X protein (rTX) or deficient PA-X protein (rTX-FS), and the established culture system of chBM-DCs, results showed PA-X protein inhibited viral replication in chBM-DCs but not in non-immune chicken cells (DF-1). Moreover, PA-X protein downregulated the expression of phenotypic markers (CD40, CD86, and MHCII) and proinflammatory cytokine (IL-12 and IL-1β) of chBM-DCs. The mixed lymphocyte reaction between chBM-DCs and chicken T cells showed PA-X protein significantly decreased H9N2-infected chBM-DCs to induce T cell proliferation, implying a suppression of the DC-induced downstream T cell response. Taken together, these findings indicated that PA-X protein is a key viral protein to help H9N2 subtype AIVs escape the innate immunity of chBM-DCs.

Joining Forces in Basic Science: ITS Meeting 2.0

The second International Transplant Science (ITS) meeting jointly organized by the European Society for Organ Transplantation (ESOT), the American Society of Transplantation (AST), and The Transplantation Society (TTS) took place in May 2022 in one of Europe's most iconic cities: Berlin, Germany. The ITS meeting 2022 was designed to serve as an international platform for scientific discussions on the latest ground-breaking discoveries in the field, while providing an excellent opportunity to present cutting-edge research to the scientific community. We think this is fundamental for the exchange of new ideas and establishment of collaborative work between advanced transplant experts, young professionals and early-stage researchers and students. Scientific sessions tackled hot topics in transplantation such as mechanisms of tolerance, biomarkers, big data and artificial intelligence. Our educational pre-meeting focused on the breakthrough and challenges in single-cell multimodal omics. The program included panel discussions illuminating various topics concerning conflicts and problems related to gender, such as challenges for female scientists. Attendees returned to their institutes with not only profound knowledge of the latest discoveries, technologies, and concepts in basic and translational science, but also inspired and excited after discussions and networking sessions with fellow scientists which have been duly missed during the pandemic.

PA-X protein assists H9N2 subtype avian influenza virus in escaping immune response of mucosal dendritic cells

H9N2 subtype low pathogenicity avian influenza virus (AIV) poses a potential zoonotic risk. PA-X, a novel protein generated by PA gene ribosomal frameshift, is considered to be the virulence factor of H9N2 subtype AIVs. Our study found that rTX possessing PA-X protein enhanced the mammalian pathogenicity of H9N2 subtype AIVs compared with PA-X-deficient virus (rTX-FS). Furthermore, PA-X protein inhibited H9N2 subtype AIVs to infect dendritic cells (DCs), but not nonimmune cells (MDCK cells). Meanwhile, PA-X protein suppressed the phenotypic expression (CD80, CD86, CD40 and MHCII), early activation marker (CD69) and pro-inflammatory cytokines (IL-6 and TNF-α), whereas increased anti-inflammatory cytokine (IL-10) in DCs. After intranasally viral infection in mice, we found that PA-X protein of H9N2 subtype AIVs reduced CD11b+ and CD103+ subtype mucosal DCs recruitment to the nasal submucosa by inhibiting CCL20 expression. Moreover, PA-X protein abolished the migratory ability of CD11b+ and CD103+ DCs into draining cervical lymph nodes by down-regulating CCR7 expression. The rTX-infected DCs significantly impaired the allogeneic CD4+ T cell proliferation, suggesting PA-X protein suppressed the immune functions of DCs for hindering the downstream immune activation. These findings indicated that PA-X protein assisted H9N2 subtype AIVs in escaping immune response of mucosal DCs for enhancing the pathogenicity.

Differences in CD80 and CD86 transendocytosis reveal CD86 as a key target for CTLA-4 immune regulation

CD28 and CTLA-4 (CD152) play essential roles in regulating T cell immunity, balancing the activation and inhibition of T cell responses, respectively. Although both receptors share the same ligands, CD80 and CD86, the specific requirement for two distinct ligands remains obscure. In the present study, we demonstrate that, although CTLA-4 targets both CD80 and CD86 for destruction via transendocytosis, this process results in separate fates for CTLA-4 itself. In the presence of CD80, CTLA-4 remained ligand bound, and was ubiquitylated and trafficked via late endosomes and lysosomes. In contrast, in the presence of CD86, CTLA-4 detached in a pH-dependent manner and recycled back to the cell surface to permit further transendocytosis. Furthermore, we identified clinically relevant mutations that cause autoimmune disease, which selectively disrupted CD86 transendocytosis, by affecting either CTLA-4 recycling or CD86 binding. These observations provide a rationale for two distinct ligands and show that defects in CTLA-4-mediated transendocytosis of CD86 are associated with autoimmunity.

Altered DNA methylation pattern characterizes the peripheral immune cells of patients with autoimmune hepatitis

BACKGROUND AND AIMS

Little is known about the impact of DNA methylation modifications on autoimmune hepatitis (AIH) pathogenesis and therapeutic response. We investigated the potential alterations of DNA methylation in AIH peripheral lymphocytes at diagnosis and remission.

METHODS

Ten AIH patients at diagnosis (time-point 1; AIH-tp1), 8/10 following biochemical response (time-point 2; AIH-tp2), 9 primary biliary cholangitis (PBC) and 10 healthy controls (HC) were investigated. Peripheral CD19(+) and CD4(+) cells were isolated. Global DNA methylation (5^m C)/hydroxymethylation (5^hm C) was studied by ELISAs. mRNA of DNA methylation (DNMT1/3A/3B) and their counteracting hydroxymethylation enzymes (TET1/2/3) was determined by quantitative RT-PCR. Epigenome wide association study (EWAS) was performed in CD4(+) cells (Illumina HumanMethylation 850 K array) in AIH and HC. Total 5^m C/5^hm C was also assessed by immunohistochemistry (IHC) on paraffin-embedded liver sections.

RESULTS

Reduced TET1 and increased DNMT3A mRNA levels characterized CD19(+) and CD4(+)-lymphocytes from AIH-tp1 compared to HC and PBC, respectively, without affecting global DNA 5^m C/5^hm C. In AIH-tp1, CD4(+) DNMT3A expression was negatively correlated with serum IgG (P = .03). In remission, DNMT3A decreased in both CD19(+) and CD4(+) cells compared to AIH-tp1 (P = .02, P = .03 respectively). EWAS in CD4(+) cells from AIH patients confirmed important modifications in genes implicated in immune responses (HLA-DP, TNF, lnRNAs and CD86). IHC showed increased 5^hm C staining of periportal infiltrating lymphocytes in AIH-tp1 compared to HC and PBC.

CONCLUSION

Altered TET1 and DNMT3A expressions, characterize peripheral lymphocytes in AIH. DNMT3A was associated with disease activity and decreased following remission. Gene DNA methylation modifications affect immunological pathways that may play an important role in AIH pathogenesis.

Characterization of Peripheral Blood TCR in Patients with Type 1 Diabetes Mellitus by BD RhapsodyTM VDJ CDR3 Assay

The sequence of complementarity-determining region 3 of the T-cell receptor (TCR) varies widely due to the insertion of random bases during V-(D)-J recombination. In this study, we used single-cell VDJ sequencing using the latest technology, BD Rhapsody, to identify the TCR sequences of autoreactive T-cells characteristic of Japanese type 1 diabetes mellitus (T1DM) and to clarify the pairing of TCR of peripheral blood mononuclear cells from four patients with T1DM at the single-cell level. The expression levels of the TCR alpha variable (TRAV) 17 and TRAV21 in T1DM patients were higher than those in healthy Japanese subjects. Furthermore, the Shannon index of CD8⁺ T cells and FOXP3⁺ cells in T1DM patients was lower than that of healthy subjects. The gene expression of PRF1, GZMH, ITGB2, NKG7, CTSW, and CST7 was increased, while the expression of CD4, CD7, CD5, HLA-A, CD27, and IL-32 was decreased in the CD8⁺ T cells of T1DM patients. The upregulated gene expression was IL4R and TNFRSF4 in FOXP3⁺ cells of T1DM patients. Overall, these findings demonstrate that TCR diversity and gene expression of CD8⁺ and FOXP3⁺ cells are different in patients with T1DM and healthy subjects.

Single-cell multi-omics analysis reveals IFN-driven alterations in T lymphocytes and natural killer cells in systemic lupus erythematosus

Background: The characterisation of the peripheral immune system in the autoimmune disease systemic lupus erythematosus (SLE) at the single-cell level has been limited by the reduced sensitivity of current whole-transcriptomic technologies. Here we employ a targeted single-cell multi-omics approach, combining protein and mRNA quantification, to generate a high-resolution map of the T lymphocyte and natural killer (NK) cell populations in blood from SLE patients. Methods: We designed a custom panel to quantify the transcription of 534 genes in parallel with the expression of 51 surface protein targets using the BD Rhapsody AbSeq single-cell system. We applied this technology to profile 20,656 T and NK cells isolated from peripheral blood from an SLE patient with a type I interferon (IFN)-induced gene expression signature (IFN hi), and an age- and sex- matched IFN low SLE patient and healthy donor. Results: We confirmed the presence of a rare cytotoxic CD4 + T cell (CTL) subset, which was exclusively present in the IFN hi patient. Furthermore, we identified additional alterations consistent with increased immune activation in this patient, most notably a shift towards terminally differentiated CD57 + CD8 + T cell and CD16 + NK dim phenotypes, and the presence of a subset of recently-activated naïve CD4 + T cells. Conclusions: Our results identify IFN-driven changes in the composition and phenotype of T and NK cells that are consistent with a systemic immune activation within the IFN hi patient, and underscore the added resolving power of this multi-omics approach to identify rare immune subsets. Consequently, we were able to find evidence for novel cellular peripheral biomarkers of SLE disease activity, including a subpopulation of CD57 + CD4 + CTLs.

The Intriguing Landscape of Single-Cell Protein Analysis

Profiling protein expression at single-cell resolution is essential for fundamental biological research (such as cell differentiation and tumor microenvironmental examination) and clinical precision medicine where only a limited number of primary cells are permitted. With the recent advances in engineering, chemistry, and biology, single-cell protein analysis methods are developed rapidly, which enable high-throughput and multiplexed protein measurements in thousands of individual cells. In combination with single cell RNA sequencing and mass spectrometry, single-cell multi-omics analysis can simultaneously measure multiple modalities including mRNAs, proteins, and metabolites in single cells, and obtain a more comprehensive exploration of cellular signaling processes, such as DNA modifications, chromatin accessibility, protein abundance, and gene perturbation. Here, the recent progress and applications of single-cell protein analysis technologies in the last decade are summarized. Current limitations, challenges, and possible future directions in this field are also discussed.

Distinguishing activated T regulatory cell and T conventional cells by single cell technologies

Resting conventional T cells (Tconv) can be distinguished from T regulatory cells (Treg) by the canonical markers FOXP3, CD25 and CD127. However, the expression of these proteins alters after T‐cell activation leading to overlap between Tconv and Treg. The objective of this study was to distinguish resting and antigen‐responsive T effector (Tconv) and Treg using single‐cell technologies. CD4⁺ Treg and Tconv cells were stimulated with antigen and responsive and non‐responsive populations processed for targeted and non‐targeted single‐cell RNAseq. Machine learning was used to generate a limited set of genes that could distinguish responding and non‐responding Treg and Tconv cells and which was used for single‐cell multiplex qPCR and to design a flow cytometry panel. Targeted scRNAseq clearly distinguished the four‐cell populations. A minimal set of 27 genes was identified by machine learning algorithms to provide discrimination of the four populations at >95% accuracy. In all, 15 of the genes were validated to be differentially expressed by single‐cell multiplex qPCR. Discrimination of responding Treg from responding Tconv could be achieved by a flow cytometry strategy that included staining for CD25, CD127, FOXP3, IKZF2, ITGA4, and the novel marker TRIM which was strongly expressed in Tconv and weakly expressed in both responding and non‐responding Treg. A minimal set of genes was identified that discriminates responding and non‐responding CD4⁺ Treg and Tconv cells and, which have identified TRIM as a marker to distinguish Treg by flow cytometry.

The Anti-Inflammatory and Anti-Pruritus Mechanisms of Huanglian Jiedu Decoction in the Treatment of Atopic Dermatitis

Atopic dermatitis (AD) is a common chronic skin disease driven by a T-cell-mediated immune response, with inflammation and pruritus being its main clinical manifestations. Huanglian Jiedu decoction (HLJDT), which is an ancient Chinese medicine herbal formula derived from Wai-Tai-Mi-Yao, is a potentially effective treatment for AD. We aimed to clarify the anti-inflammatory and anti-pruritus mechanisms of HLJDT in AD treatment. We performed immunohistochemistry, Western blotting, reverse transcriptase-polymerase chain reaction, Luminex-based direct multiplex immunoassay, enzyme-linked immunosorbent assays, and flow cytometry to address the abovementioned aims. HLJDT significantly reduced clinical symptoms and ear swelling in AD-like mice by inhibiting the production of cytokines [histamine, interleukin (IL)-3, IL-4, IL-5, IL-13, IL-17A, IL-31, and IL-33], substance P (SP), transient receptor potential cation channel subfamily V member 1 (TRPV-1), and gastrin-releasing peptide (GRP). Additionally, HLJDT significantly suppressed the protein expression levels and positive cell percentage of CD28, CD80, CD86, CD207, CD326, MHCII, and OX40 in the lymphoid nodes. Moreover, HLJDT significantly suppressed mRNA and protein expression of tyrosine–protein kinase (JAK1), histamine H4 receptor, and IL-4Rα, as well as the protein expression of GRP, SP, and TRPV-1 in the root ganglion. Our findings indicate that HLJDT can treat AD by regulating the antigen presentation function of dendritic cells, weakening T-lymphocyte activation, and subsequently exerting anti-inflammatory and anti-pruritus effects.

Candidate host epigenetic marks predictive for HIV reservoir size, responsiveness to latency reversal, and viral rebound

OBJECTIVE

This study aimed to identify candidate host epigenetic biomarkers predicting latency reversal agents (LRA) efficacy and HIV-1 rebound kinetics during analytical treatment interruption (ATI).

DESIGN

Retrospective longitudinal epigenetic profiling study from 13 people with HIV (PWH) on virologically suppressive antiretroviral therapy (ART) that participated in a LRA (HDAC inhibitor) clinical trial (NCT01680094) and a subsequent optional ATI to monitor for viral recrudescence after ART cessation.

METHODS

Genome-wide DNA methylation (DNAm) in purified CD4+ T cells was measured at single-nucleotide resolution using the Infinium MethylationEPIC array. HIV-1 DNA and RNA measures were previously assessed by PCR-based methods and the association of DNAm levels at regulatory sites of the human genome were examined with reservoir size, responsiveness to LRA, and time to viral rebound following ATI.

RESULTS

A distinct set of 15 candidate DNAm sites in purified CD4+ T cells at baseline pre-LRA and pre-ATI significantly correlated with time to viral rebound. Eight of these DNAm sites occurred in genes linked to HIV-1 replication dynamics including (SEPSECS, cg19113954), (MALT1, cg15968021), (CPT1C, cg14318858), (CRTAM, cg10977115), (B4GALNT4, cg04663285), (IL10, cg16284789), (TFPI2, cg19645693), and (LIFR, cg26437306); with the remaining sites at intergenic regions containing regulatory elements. Moreover, baseline DNAm states related to total HIV-1 DNA levels and the fold change in unspliced cell-associated HIV RNA following LRA treatment.

CONCLUSION

Preexisting host epigenetic states may determine HIV-1 rebound kinetics and reservoir maintenance. These findings suggest integrating a suite of DNA methylation markers to improve optimal participant selection and drug regimen in future HIV cure clinical trials.