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GZMK+CD8+ T cells target a specific acinar cell type in Sjögren's disease.

OBJECTIVES: Sjögren's disease (SjD) is a systemic autoimmune disorder characterized by dysfunction of exocrine glands, particularly the salivary and lacrimal glands, with no clear etiology or effective therapy. This study explores the complex interplay of varied cell types in the salivary glands and their role in the pathology of Sjögren's disease. METHODS: Utilizing single-cell and spatial transcriptomics alongside spatial immunophenotyping to analyze human minor salivary glands, we developed a comprehensive understanding of the cellular landscape of non-SjD salivary glands and how that landscape changes in SjD patients. In vitro cellular assays and novel patient-derived primary epithelial cells were co-cultured with autologous T cells to confirm effector states and the delivery and effect of disease-associated granzymes. RESULTS: We identified previously unrecognized heterogeneity among acinar cells, including a PRR4⁺CST3⁺WFDC2⁻ seromucous acinar population that is selectively lost in Sjögren's disease. Expression and organizational changes were linked to clinical features: (i) T cells in the glands of SSA⁺, high-focus score patients showed increased transcriptional signatures of activation, antigen presentation, and apoptosis resistance compared with patients with mild or moderate disease, and (ii) patients with low immune infiltration exhibited distinct epithelial organization. Notably, GZMK⁺CD8⁺ T cells, which accumulate with disease severity, displayed a cytotoxic transcriptional program, degranulated upon stimulation ex vivo, and localized spatially with immune-engaged epithelial cells. Functional assays demonstrated that GZMK activates interferon signaling in vitro, and autologous co-cultures of patient-derived T cells and epithelial cells validated these findings. CONCLUSIONS: Using single-cell and spatial transcriptomics and proteomics, this study identifies a selective loss of PRR4⁺CST3⁺WFDC2⁻ seromucous acinar cells and a rise in GZMK⁺CD8⁺ T cells in Sjögren's disease, revealing distinct immune-mediated epithelial remodeling and interferon-driven dysfunction across diverse clinical presentations. These findings uncover a novel sub-cytolytic effector mechanism by which GZMK⁺CD8⁺ T cells impair mitochondrial integrity and activate innate immune signaling, linking epithelial injury to type I interferon responses and offering new therapeutic targets.

Humans

MicroRNA-directed program of cytotoxic CD8+ T-cell differentiation.

Acquisition of effector properties is a key step in the generation of cytotoxic T lymphocytes (CTLs). Here we show that inflammatory signals regulate Dicer expression in CTLs, and that deletion or depletion of Dicer in mouse or human activated CD8(+) T cells causes up-regulation of perforin, granzymes, and effector cytokines. Genome-wide analysis of microRNA (miR, miRNA) changes induced by exposure of differentiating CTLs to IL-2 and inflammatory signals identifies miR-139 and miR-150 as components of an miRNA network that controls perforin, eomesodermin, and IL-2Rα expression in differentiating CTLs and whose activity is modulated by IL-2, inflammation, and antigenic stimulation. Overall, our data show that strong IL-2R and inflammatory signals act through Dicer and miRNAs to control the cytolytic program and other aspects of effector CTL differentiation.

Adoptive Transfer

Distinct immune landscapes characterize highly versus minimally invasive brain metastases.

Brain metastases (BrMs) occur in approximately 30% of cancer patients, causing nearly one-fifth of cancer deaths. While immune checkpoint inhibitors (ICIs) benefit some BrM patients, responses remain highly variable. This variability partly reflects distinct histopathological growth patterns that include minimally invasive (MI) and highly invasive (HI) brain BrMs. Here we show that MI BrMs exhibit robust immune infiltration, whereas HI lesions are immunosuppressed. However, histological differentiation between MI and HI can be challenging because of subjective margin assessment. Here, using highly multiplexed spatial proteomics on 119 tumor sections from 46 patients with BrMs, we identify CHI3L1 as a key mediator of the immunosuppressive microenvironment in HI BrMs. In preclinical models, genetic deletion of CHI3L1 converts immune-cold metastases into lymphocyte-rich, ICI-responsive lesions infiltrated by granzyme B+ CD8+ T cells. In BrM patients treated with ICI, immunohistochemical quantification of CHI3L1 expression was a stronger predictor of ICI response than traditional MI/HI classification. Thus, CHI3L1 represents a promising biomarker and therapeutic target for BrMs.

Humans

An Immunosenescent CD8+ T Cell Subset in Patients with Axial Spondyloarthritis and Psoriatic Arthritis Links Spontaneous Motility to Telomere Shortening and Dysfunction.

OBJECTIVE: A pathogenetic role of CD8+ T lymphocytes in radiographic axial spondyloarthritis (r-axSpA) and other spondyloarthritis (SpA) is sustained by genome-wide association studies and by the expansion of public T cell clonotypes in the target tissues. This study investigates the migration of CD8+ T cells along with their phenotype and functions in patients with r-axSpA and psoriatic arthritis (PsA). METHODS: Peripheral blood CD8+ and CD4+ T cells were isolated from patients with r-axSpA (n = 128), PsA (n = 60), and rheumatoid arthritis (RA) (n = 74) and healthy donors (HDs) (n = 79). Transwell migration assay was performed in the presence of different chemokines. CD8+ T cell immunoprofiling and effector functions were assessed by multiparametric flow cytometry. Transcriptome signature was evaluated by RNA sequencing analysis, whereas telomere length and dysfunction were measured by reverse transcriptase-polymerase chain reaction and immunofluorescence-fluorescence in situ hybridization, respectively. RESULTS: A significantly higher number of CD8+ T cells migrating in the absence of chemokine stimuli was found in patients with SpA compared with HDs and patients with RA. This subset, producing cytotoxic (granzyme B, perforin, granulysin) and proinflammatory molecules (tumor necrosis factor), was significantly enriched in terminally differentiated (CCR7-CD45RA+) and senescent (CD28-CD57+) cells having a gene expression profile characterized by cytolytic signature and natural killer markers. Remarkably, these spontaneously migrating CD8+ T cells showed DNA damage response activation, telomere shortening, and dysfunction. CONCLUSION: These data describe a terminally differentiated CD8+ T cell subset with a senescent and cytotoxic/proinflammatory profile and an intrinsic invasive potential enriched in patients with SpA that represents a possible player in disease pathogenesis.

Humans

Dengue virus infection elicits highly polarized CX3CR1+ cytotoxic CD4+ T cells associated with protective immunity.

Dengue virus (DENV) is a rapidly spreading pathogen with unusual pathogenesis, and correlates of protection from severe dengue disease and vaccine efficacy have not yet been established. Although DENV-specific CD8(+) T-cell responses have been extensively studied, the breadth and specificity of CD4(+) T-cell responses remains to be defined. Here we define HLA-restricted CD4(+) T-cell epitopes resulting from natural infection with dengue virus in a hyperepidemic setting. Ex vivo flow-cytometric analysis of DENV-specific CD4(+) T cells revealed that the virus-specific cells were highly polarized, with a strong bias toward a CX3CR1(+) Eomesodermin(+) perforin(+) granzyme B(+) CD45RA(+) CD4 CTL phenotype. Importantly, these cells correlated with a protective HLA DR allele, and we demonstrate that these cells have direct ex vivo DENV-specific cytolytic activity. We speculate that cytotoxic dengue-specific CD4(+) T cells may play a role in the control of dengue infection in vivo, and this immune correlate may be a key target for dengue virus vaccine development.

Adult

Intrathecally expanded GZMK+/GZMH+ CD8 T cells targeting EBV antigens may reduce severity of Multiple Sclerosis.

Combining cerebrospinal fluid B cell receptor and T cell receptor repertoire analysis with transcriptional/ flow cytometry cellular profiles in hundreds of deeply-phenotyped people with Multiple Sclerosis (pwMS) and controls, we identified intrathecal expansion of anti-viral, cytotoxic, granzymes H/K (GZMH+/GZMK+) double positive (DP) CD8+ T cells that recognize EBV epitopes in pwMS. DP CD8+ T cells are activated and expanded by, and kill autologous, EBV-infected CSF B cell lines in-vitro. Correlations of surrogate transcriptional profiles with clinical and imaging outcomes infer a beneficial role for EBV-targeting DP CD8+ T cells, as untreated pwMS with proportionally higher DP CD8+ T cells to intrathecal B cells accumulate neurological disability slower. MS therapies also increase ratios of beneficial CD8+ T cell responses to intrathecal B cells, consistent with their ability to inhibit disability progression. This study provides indirect evidence that intrathecal EBV infection participates in disability accumulation in pwMS.

Journal Article

ITIH4 alleviates OVA-induced asthma by regulating lung-gut microbiota.

BACKGROUND: Inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4), a Type 2 acute phase protein, is critical for resolving inflammation and promoting tissue repair. While its role in chronic respiratory diseases is recognized, its effects on asthma remain unclear. This study investigated the effects of ITIH4 on the modulation of lung and gut microbiota, the attenuation of allergic inflammation, and the improvement of respiratory outcomes in an asthma mouse model. METHODS: Six-week-old male Balb/c mice were divided into five groups: control, ITIH4, ovalbumin (OVA), and two OVA&#x2009;+&#x2009;ITIH4 treatment groups at different doses. Lung function and oxygen saturation were measured, and bronchoalveolar lavage fluid (BALF) was analyzed for white blood cell counts and cytokines. Lung and gut microbiota were profiled using 16&#xa0;S rRNA gene sequencing, and short-chain fatty acids (SCFAs) were measured using gas chromatography-mass spectrometry (GC-MS). Proteomic profiling of intestinal tissues was conducted to identify ITIH4-associated signaling pathways. RESULTS: ITIH4 administration significantly mitigated OVA-induced asthma symptoms by reducing weight loss, airway resistance, and tissue damping (p&#x2009;<&#x2009;0.05). Histological analysis showed decreased airway wall thickening and lung injury scores (p&#x2009;<&#x2009;0.05). ITIH4 also lowered BALF eosinophils and lymphocytes, IgE, and Th2 cytokines (IL-4, IL-5, and IL-13) (p&#x2009;<&#x2009;0.05). ITIH4 treatment modulated microbiome composition, enriching Gram-positive taxa (Nocardioidaceae and Acholeplasmataceae) and depleting Gram-negative Helicobacteraceae (p&#x2009;<&#x2009;0.05). SCFAs correlated with microbiome alterations, notably reduced 4-methylpentanoic acid levels (p&#x2009;<&#x2009;0.05). Proteomic analysis revealed a dose-dependent activation of granzyme A signaling and suppression of metabolic and solute transport pathways. CONCLUSIONS: ITIH4 ameliorates asthma symptoms by modulating lung and gut microbiota, dampening Th2-driven inflammation, and restoring mucosal immune balance. These findings support ITIH4 as a potential candidate for microbiome-targeted asthma therapy.

Animals

Senescent fibroblasts drive CD8+ T cell dysfunction in colorectal cancer via CD36-mediated lipid transfer and peroxidation.

BACKGROUND: Functional exhaustion of tumor-infiltrating CD8+ T cells represents a hallmark of colorectal cancer (CRC) immunosuppression, though its mechanistic drivers remain elusive. Given the established correlation between CRC progression and stromal senescence characterized by pathological lipid accumulation and impaired immunity, we investigated whether and how senescent fibroblasts actively regulate CD8+ T cell dysfunction. METHODS: Single-cell RNA sequencing (scRNA-seq) analysis was conducted to unveil the diverse fibroblast populations and the significant lipid metabolism changes between senescent fibroblasts and non-senescent fibroblasts in human CRC specimens and adjacent normal mucosa. Machine-learning identified senescent fibroblasts with a distinct gene signature. Cell-cell communication analysis was used to evaluate the interactions between senescent fibroblasts and CD8+ T cells in colorectal cancer. Co-culture experiments were conducted among senescent fibroblasts, CD8+ T cells and patient-derived organoids of CRC (CRC-PDOs), with the results evaluated with high-content imaging and propidium iodide/Hoechst 33,342 staining. Flow cytometry, ELISA and lipid pulse-chase with BODIPY FL C16 were performed to detect the alterations of CD8+ T cell cytotoxic function and metabolic status. AOM/DSS-induced CRC mouse model was used to conduct in vivo validation to evaluate whether senolytics could suppress CRC progression. Patients from the Cancer Genome Atlas colorectal cancer cohort were stratified into CD36-high and CD36-low groups by median expression, and drug sensitivity for GDSC2 compounds was predicted computationally using the oncoPredict R package. RESULTS: ScRNA-seq demonstrated the specific cell population presence and divergence of senescent fibroblasts between neoplastic and histologically normal adjacent cell clusters in CRC. Random Forest was employed for cell senescence classification. Feature importance analysis identified five genes as key contributors to the model&#x2019;s decision process. Cell-cell communication analysis revealed enhanced interactions between senescent fibroblasts and CD8+ T cells in CRC. Co-culture of senescent fibroblasts significantly impaired the cytotoxic functions of CD8+ T cells on CRC-PDOs, which was reflected by the declined proportions of granzyme B (GZMB) + and interferon gamma (IFN&#x3b3;) + CD8+ T cells and enhanced viability of CRC-PDOs. Mechanistically, the co-culture with senescent fibroblasts promoted the lipid shuttling into CD8+ T cells to induce lipid peroxidation and downstream impairment of cytotoxicity. Furthermore, the inhibition of CD36, the specific scavenger receptor for lipid uptake of CD8+ T cells, effectively suppressed lipid transfer and peroxidation thereby preserving the effector functions of CD8+ T cells and ultimately promoting tumor apoptosis. Complementarily, in vivo senolytic treatment significantly suppressed CRC progression in AOM-DSS CRC mouse models. Top 12 therapeutic agents were identified significantly enhanced predicted efficacy in CD36-high tumors. CONCLUSIONS: Our study identified a substantial population of senescent fibroblasts in human CRC through single cell transcriptomics, machine-learning and clinical biopsies. These senescent fibroblasts impair CD8+ T cell-mediated killing of CRC-PDOs via CD36-dependent lipid transfer, suggesting senolytic targeting of stromal cells as a promising immunotherapeutic strategy for CRC.

Colorectal Neoplasms

Natural killer (NK) cells with downregulated activating receptors and IL-10 production promote Trypanosoma cruzi T-cell responses in subjects in the Chronic phase of Trypanosoma cruzi infection: An exploratory immunological analysis.

BACKGROUND: Subjects with chronic Chagas disease and no signs of heart disease exhibit decreased NKp46 expression, high CD57 expression, and IL-10 production by NK cells. This study provides a detailed characterization of the phenotype and function of NK cells according to the severity of heart disease, and evaluates how these changes following treatment with benznidazole, as well as their association with Trypanosoma cruzi-specific T-cell responses. METHODS: The phenotype and function of NK cells in a cohort of 51 subjects infected with Trypanosoma cruzi and exhibiting varying degrees of heart disease were evaluated using high-dimensional flow cytometry and Boolean gating analysis. ELISPOT assays were performed to measure IFN-&#x3b3; and IL-2 production in response to T. cruzi antigens, using CD56, CD4 and CD8-depleted PBMC. RESULTS: In contrast to individuals without heart disease, those with advanced cardiomyopathy have an increased number of NK cells that express the activating receptors NKp46 and CD16, as well as the differentiation marker CD57. NK cells in subjects with advanced cardiomyopathy were also found to be enriched in CD56+CD107+granzyme B+TNF-&#x3b1;+ cells and depleted of CD56+IL-10+ cells. The function of NK cells shifted towards monofunctionality in subjects with declining T. cruzi-specific antibodies following treatment with benznidazole. Eliminating CD56+ cells significantly decreased the number of IFN-&#x3b3;-producing cells in response to T. cruzi. CONCLUSIONS: In chronic T. cruzi infection, NK-cell function may be balanced by the downregulation of activating receptors and IL-10 production, However, parasite persistence may desensitize the regulation of NK activating receptors, enabling NK cells to exert a potent polyfunctional cytotoxicity that potentially induce tissue damage.

Humans

GCH1, identified by a ferroptosis-related prognostic model, contributes to progression and drug resistance of esophageal cancer.

OBJECTIVE: Esophageal cancer has a poor prognosis and limited treatment options. Ferroptosis, an iron-dependent cell death pathway, is a promising therapeutic target; however, its significance in esophageal cancer remains largely unexplored. Here, we investigated the prognostic significance of ferroptosis-related genes in esophageal cancer and identified a key functional regulator that may serve as a therapeutic target. METHODS: We analyzed ferroptosis-related gene expression profiles with The Cancer Genome Atlas-Esophageal Carcinoma (TCGA-ESCA) cohort and constructed a prognostic risk model using LASSO Cox regression analysis. Among the genes in this model, GTP cyclohydrolase 1 (GCH1) was selected for functional investigation, based on its established role in antioxidant defense. Subsequently, in vitro experiments were performed to assess the effects of GCH1 knockdown on cell proliferation, migration, clonogenicity, and ferroptosis-related biochemical indicators. The role of GCH1 in antitumor immunity was evaluated through co-culture of esophageal cancer cells with activated T cells, and drug sensitivity was assessed using cytotoxicity assays. RESULTS: A prognostic model consisting of nine ferroptosis-related genes (STC2, TRIB3, HMGB3, CXCL8, GCH1, PARP10, APOE, MTIM, and GPER1) with reliable risk stratification was constructed. The prognostic model could reflect the differences in drug responses and immune cell infiltration. GCH1 knockdown suppressed esophageal cancer cell proliferation, migration, and clonogenicity. Furthermore, GCH1 knockdown increased the intracellular levels of reactive oxygen species, lipid peroxidation, and ferrous iron (Fe2+). Co-culture assays demonstrated that GCH1 knockdown in tumor cells increased the production of granzyme B and interferon-&#x3b3; by CD8+ T cells. Moreover, GCH1 silencing sensitized esophageal cancer cells to both sorafenib and cisplatin. CONCLUSIONS: This study established a ferroptosis-related prognostic model for esophageal cancer and identified GCH1 as a critical regulator that contributes to esophageal cancer progression and drug resistance. These findings suggest that targeting GCH1 may be a promising strategy to improve drug sensitivity and clinical outcomes in esophageal cancer.

Esophageal cancer