Clinical and experimental immunology最新文献

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multiple organ involvement. It is known that cytokines produced from activated CD4+ T cells play a pivotal role in the development of SLE; however, the details of pathological processes remain unclear. The purpose of this study is to elucidate the role of activated CD4+ T cells on the pathogenesis of lupus using SLE murine models induced by toll like receptor 7 agonist imiquimod (IMQ). Lupus was induced in wild-type (WT) and interferon γ (IFNγ)-deficient (IFNγ-/-) mice by topical IMQ treatment. Splenic T and B cell subsets were analyzed by flow cytometry. CD4+ T cells and B cells were isolated for co-culture to assess B cell differentiation and IgG production. Comprehensive lupus-like phenotypes were evaluated. Single-cell RNA sequencing (scRNA-seq) was performed to characterize IFNγ-associated cellular and molecular pathways. IMQ treatment increased IFNγ-producing CD4+ T cells, along with Tfh cells, Tph cells, age-associated B cells, and plasma cells in WT mice. CD4+ T cells from IMQ-treated WT mice promoted B-cell differentiation and IgG production in co-culture assays. In IFNγ-/- mice, lupus-like phenotypes were significantly attenuated, and co-cultured B cells showed reduced differentiation and IgG production. Single-cell RNA sequencing revealed that IFNγ plays a critical role in promoting B cell differentiation and autoantibody production. IFNγ derived from activated CD4+ T cells plays a critical role in driving B-cell differentiation and promoting autoantibody production in IMQ-induced lupus.

Lysophosphatidic acid (LPA) is a crucial bioactive lipid mediator involved in various physiological processes; however, its role in macrophage polarization remains poorly understood; therefore, this study aimed to elucidate the modulatory effect of LPA on macrophage polarization, particularly its ability to shift M1 macrophages towards an M2-like phenotype, using murine macrophage RAW264.7 cells to confirm the expression of LPA receptor 1 (LPAR1) through immunofluorescence staining, which revealed that treatment of resting MO macrophages with LPA decreased inflammatory cytokines (IL-6, TNF-α) and increased TGF-β, with similar effects observed in LPS-stimulated cells and reversed by the LPAR1 inhibitor AM095, and immunostaining demonstrated a notable shift from an M1- to M2-like phenotype, as evidenced by an increase in the arginase-1/CD68 ratio; furthermore, LPA significantly decreased lactate production and increased ATP production in M1 macrophages, promoting a shift towards oxidative phosphorylation and suggesting metabolic reprogramming towards an M2-like phenotype, significantly influencing macrophage polarization and promoting a shift from a pro-inflammatory M1-like phenotype to an anti-inflammatory M2-like phenotype; these results suggest that treatment with LPA may help ameliorate diseases characterized by aberrant macrophage polarization, providing insights for the development of potential therapeutic strategies for inflammatory and autoimmune diseases.

Increased glycolytic metabolism in synovial fibroblasts contributes to their activated phenotype in rheumatoid arthritis (RA). Our previous results revealed that the activation of the dopamine D3 receptor (D3R) in mast cells reduced inflammation in a mouse model of RA. In this study, we explored the role of D3R in regulating dopamine-induced activation and glycolysis in synovial fibroblasts from patients with RA (RASFs). RASFs were cultured in the presence of dopamine. Pharmacological modulation of D3R-by-D3R agonist (7-OHDPAT) and antagonist (NGB2904) was used to investigate the regulatory role of D3R in dopamine-induced activation and glycolysis in RASFs. Dopamine stimulation induced a dose-dependent increase in cell viability and α-SMA expression in RASFs. Dopamine also caused significant and dose-dependent upregulation of glycolysis-related enzymes in RASFs. Treatment with 7-OH-DPAT inhibited dopamine-induced increases in α-SMA expression and inflammatory response in RASFs, whereas NGB2904 treatment resulted in the enhanced effects stimulated by dopamine. NGB2904 treatment upregulated glycolysis and the expression of glycolytic enzymes induced by dopamine, whereas 7-OH-DPAT treatment downregulated glycolysis and glycolytic enzymes in RASFs. NGB2904 attenuated the ability of 7-OH-DPAT to inhibit the dopamine-induced elevation in cAMP levels of RASFs. Involvements of the cAMP pathway was confirmed by findings that H89 (a PKA inhibitor) abrogated the upregulation of activation, glycolysis, and expression of glycolytic enzymes mediated by the D3R antagonist, NGB2904, in RASFs. D3R downregulates dopamine-induced activation and glycolysis of RASFs by suppressing PKA activity. Therefore, inhibition of glycolysis by manipulating the D3R pathway may provide a novel therapeutic strategy to reduce the activation of RASFs.

Functional approaches to properly examine individual's susceptibility to complement dysregulation are limited. We assessed ex vivo complement activation induced by sera from 38 healthy donors on resting microvascular endothelial cells with or without complement dysregulation (OX-24 monoclonal antibody). Following incubation, immunofluorescence was used to quantify membrane-bound C3b/iC3b and C5b-9 with a computer-assisted method (H-score). C3a and C5a anaphylatoxins were quantified in supernatants by ELISA. Genetic sequencing of 32 donors was also performed to identify variants in alternative pathway genes. Elevated complement deposition was defined by H-scoreC3c > 50 and/or H-scoreC5b-9 > 30. Combined analysis of C3b/iC3b and C5b-9 deposition in 35 donors showed that one donor (2.8%) had an isolated increase in C3b/iC3b deposits, three (8.6%) had an isolated increase in C5b-9 deposits, and one (2.8%) had both increased C3b/iC3b and C5b-9 deposition. Genetic analysis revealed three heterozygous rare/low frequency missense variants in CFH (p.N1050Y, p.R1210C) and CFI (p.A76G) in 3/5 donors with increased complement deposition. This model revealed distinct patterns of complement activation among healthy individuals and identified a genetic basis for dysregulation in three cases. This assay offers a promising tool to study complement activity and its mechanisms in research.

Oral squamous cell carcinoma (OSCC) is one of the most aggressive malignancies, marked by immune evasion and perineural invasion that fuel therapy resistance and poor prognosis. Long non-coding RNAs (lncRNAs) have emerged as key regulators of cancer progression, capable of shaping immune responses and promoting neural invasion. This review examines the developing concept of the nerve-immune-cancer axis, emphasizing new findings on neuroimmune interactions and how lncRNAs influence neuroinflammation. The review summarizes recent studies on the functions of lncRNAs in OSCC, particularly their role in neuroimmune interactions. This review explains how lncRNAs can influence both the immune system and nerve-related signals in OSCC. Unlike previous reviews that address neuronal or immune mechanisms in isolation, this work highlights the convergent neuroimmune pathways potentially regulated by lncRNAs and identifies critical gaps, including the lack of OSCC-specific functional studies, absence of spatial or single-cell resolution of lncRNA activity, and limited in vivo models assessing lncRNA-driven perineural invasion. By articulating these research gaps, this review outlines testable hypotheses regarding lncRNA-mediated regulation of neuroimmune crosstalk and proposes future directions such as functional genomics, spatial transcriptomics, and nerve-tumor co-culture models. Clarifying these mechanisms may enable the identification of novel biomarkers and therapeutic targets, ultimately improving the management of OSCC.

Granulomatosis with polyangiitis (GPA) is traditionally regarded as a neutrophil-driven necrotizing vasculitis. However, the potential involvement of eosinophilic inflammation has not been fully elucidated. We investigated the contribution of eosinophilic inflammation to the pathogenesis of GPA, with a particular focus on eosinophil extracellular trap formation (EETosis). This retrospective study included 52 patients, including 25 with active GPA and 27 in remission. We recorded enzyme-linked immunosorbent assay-based serum concentrations of eosinophil-derived proteins (galectin-10, eosinophil cationic protein, and eosinophil-derived neurotoxin), neutrophil-derived proteins (myeloperoxidase), and a marker for extracellular traps (citrullinated histone H3) for these patients. EETosis in tissue samples of patients was examined by immunofluorescence staining. Serum-induced EETosis was evaluated in vitro. Serum concentrations of galectin-10, eosinophil cationic protein, eosinophil-derived neurotoxin, citrullinated histone H3, and C-reactive protein and antineutrophil cytoplasmic antibody titre of patients with active GPA were significantly higher than those in remission. Galectin-10 had the strongest correlation with the Birmingham Vasculitis Activity Score (r = 0.778, P < 0.001). Increased galectin-10 levels were identified to be associated with the active stage after adjustment for glucocorticoid dose and eosinophil count. Receiver operating characteristic analyses of galectin-10 to discriminate between the active and remission phases revealed an area under the curve of 0.923, with 85.2% sensitivity and 91.1% specificity. GPA lung tissue showed lytic eosinophils and EETosis. Additionally, serum from active GPA patients induced EETosis in vitro whereas that from remission patients did not. Eosinophil activation and EETosis may contribute to the disease activity of GPA, highlighting a previously underrecognized component of its pathogenesis.

Patients with systemic lupus erythematosus (SLE) exhibit significant susceptibility to severe bacterial infections, a leading cause of mortality. A key host defence mechanism is immunothrombosis, wherein activated monocytes rapidly upregulate tissue factor (TF) to initiate localized fibrin deposition that traps and contains pathogens. Effective immunothrombosis is therefore critical for preventing microbial dissemination. This process appears deficient in SLE, a disease defined by a systemic prothrombotic state, yet poor infection outcomes. A recently discovered molecular interaction suggests that TF directly binds to the interferon-α receptor (IFNAR1), acting as a rheostat to suppress interferon signalling. We hypothesize that in SLE, this regulatory axis is disrupted. The dominant, sustained interferon-stimulated gene (ISG) signatures in monocytes limit their capacity for TF upregulation in response to bacterial challenge, thereby impairing immunothrombosis and compromising bacterial containment. Supporting this, SLE patients with secondary antiphospholipid syndrome who have lower interferon signatures display markedly elevated TF levels and a different thrombotic profile, demonstrating the inverse relationship in a clinical subset. Furthermore, TF induction in monocytes is glycolysis-dependent, and SLE monocytes are known to have profound metabolic alterations. The chronic interferon state may thus impose a metabolic constraint that further limits the bioenergetic capacity for a robust TF response. Therefore, the confluence of interferon-driven suppression and metabolic dysfunction in SLE monocytes provides a compelling explanation for the failure of immunothrombosis, directly linking a core disease feature to infection susceptibility.

Introduction: We describe the immunophenotyping and genetic analysis of HIV-uninfected apparently immunocompetent adults presenting with disseminated cryptococcosis. Cryptococci are environmentally ubiquitous fungi that may cause disseminated infection including meningitis. Cryptococcosis occurs predominantly in immunocompromised hosts and most commonly in the context of human immunodeficiency virus (HIV) infection. In apparently immunocompetent patients, cryptococcal disease is rare, often diagnosed later and associated with higher mortality. The immunologic work-up and management of this patient group is challenging and poorly studied.

Methods: Between 2015-2021, eight apparently immunocompetent adults at the time of diagnosis with cryptococcosis underwent extensive diagnostic immunological work-up including T-/B-cell subsets, immunoglobulins, T-cell proliferation and phenotyping, serum-specific antibody responses, mannose binding lectin, measurement of selected cytokines, anti-cytokine autoantibodies and targeted genetic next-generation sequencing.

Results: The production of interleukin (IL)-17 following phytohaemagglutinin (PHA) stimulation was significantly reduced in all eight patients with cryptococcosis compared to healthy controls (median IL-17 concentration in whole blood stimulation assay 88.1pg/mL in patients; 452.1pg/mL in controls, p=0.0047). In 5/5 patients tested, the percentage of CD4+ T-cells positive for IL-17, including memory CD4+CD45RO+ IL-17+ T-cells, after stimulation with staphylococcal enterotoxin B (SEB) was significantly reduced (<=0.4% cells). Reduced IgM+ memory B-cells were noted in 4/5 tested. 4/8 patients were found to have CD4 lymphopaenia. One patient with Cryptococcus gattii infection had autoantibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF). No underlying genetic causes were identified.

Conclusion: Patients had several immunological risk factors, but reduced IL-17 production was a striking feature across the cohort - a phenotype that may facilitate tailored immunotherapeutic approaches.Graphical Abstract.

Gamma-aminobutyric acid receptors (GABARs) primarily function by suppressing inflammatory responses, modulating neuronal excitability, and maintaining intracellular homeostasis, whereas N-methyl-D-aspartate receptors (NMDARs) play a key role in mediating pathological processes through the regulation of excitatory neurotransmission and immune responses. Viral infections have the capacity to modify the expression and functionality of these receptors, either directly or indirectly, thereby contributing to dysregulation within the neurological and immune systems and triggering a range of disease states. This review offers a comprehensive analysis of the mechanisms through which various viral infections interact with GABARs and NMDARs, emphasizing the possible intricate roles these receptors play in viral pathogenesis. Additionally, it underscores their potential as therapeutic targets for antiviral interventions, particularly in addressing immune dysregulation and neurological disorders.

Introduction: Murine studies have demonstrated that lymph node fibroblasts can present self-antigens via major histocompatibility complex class II molecules, inducing functional regulatory T cells and contributing to peripheral tolerance.

Methods: To investigate this phenomenon in humans, we developed an in vitro system co-culturing human lymph node fibroblasts with autologous CD4+ T cells.

Results: Our results reveal that lymph node fibroblasts upregulate human leukocyte antigen-DR (HLA-DR) upon contact with CD4+ T cells and maintain FoxP3+ regulatory T cells. This maintenance is lost upon blockade of HLA-DR or interleukin-2, and regulatory T cells are lost in the absence of lymph node fibroblasts. Furthermore, we demonstrate that lymph node fibroblasts directly isolated from rheumatoid arthritis patients exhibit a significant reduction in the frequency of HLA-DR+ cells compared to those from individuals at risk of developing the disease.

Conclusion: These findings highlight a crucial role for HLA-DR-expressing lymph node fibroblasts in maintaining peripheral tolerance within lymph nodes, a function that may be impaired in autoimmunity. Our study provides novel insights into the intricate cellular interactions within human lymph nodes and their potential implications in autoimmune disorders, opening new avenues for understanding and potentially treating these conditions.