RESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
Lupus nephritis is a potentially fatal autoimmune disease for which the current treatment is ineffective and often toxic. To develop mechanistic hypotheses of disease, we analyzed kidney samples from patients with lupus nephritis and from healthy control subjects using single-cell RNA sequencing. Our analysis revealed 21 subsets of leukocytes active in disease, including multiple populations of myeloid cells, T cells, natural killer cells and B cells that demonstrated both pro-inflammatory responses and inflammation-resolving responses. We found evidence of local activation of B cells correlated with an age-associated B-cell signature and evidence of progressive stages of monocyte differentiation within the kidney. A clear interferon response was observed in most cells. Two chemokine receptors, CXCR4 and CX3CR1, were broadly expressed, implying a potentially central role in cell trafficking. Gene expression of immune cells in urine and kidney was highly correlated, which would suggest that urine might serve as a surrogate for kidney biopsies.
Assuntos
Rim/imunologia , Nefrite Lúpica/imunologia , Biomarcadores , Biópsia , Análise por Conglomerados , Biologia Computacional/métodos , Células Epiteliais/metabolismo , Citometria de Fluxo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Imunofenotipagem , Interferons/metabolismo , Rim/metabolismo , Rim/patologia , Leucócitos/imunologia , Leucócitos/metabolismo , Nefrite Lúpica/genética , Nefrite Lúpica/metabolismo , Nefrite Lúpica/patologia , Linfócitos/imunologia , Linfócitos/metabolismo , Anotação de Sequência Molecular , Células Mieloides/imunologia , Células Mieloides/metabolismo , Análise de Célula Única , TranscriptomaRESUMO
To define the cell populations that drive joint inflammation in rheumatoid arthritis (RA), we applied single-cell RNA sequencing (scRNA-seq), mass cytometry, bulk RNA sequencing (RNA-seq) and flow cytometry to T cells, B cells, monocytes, and fibroblasts from 51 samples of synovial tissue from patients with RA or osteoarthritis (OA). Utilizing an integrated strategy based on canonical correlation analysis of 5,265 scRNA-seq profiles, we identified 18 unique cell populations. Combining mass cytometry and transcriptomics revealed cell states expanded in RA synovia: THY1(CD90)+HLA-DRAhi sublining fibroblasts, IL1B+ pro-inflammatory monocytes, ITGAX+TBX21+ autoimmune-associated B cells and PDCD1+ peripheral helper T (TPH) cells and follicular helper T (TFH) cells. We defined distinct subsets of CD8+ T cells characterized by GZMK+, GZMB+, and GNLY+ phenotypes. We mapped inflammatory mediators to their source cell populations; for example, we attributed IL6 expression to THY1+HLA-DRAhi fibroblasts and IL1B production to pro-inflammatory monocytes. These populations are potentially key mediators of RA pathogenesis.
Assuntos
Artrite Reumatoide/genética , Artrite Reumatoide/metabolismo , Perfilação da Expressão Gênica , Membrana Sinovial/metabolismo , Transcriptoma , Artrite Reumatoide/patologia , Autoimunidade/genética , Biomarcadores , Biologia Computacional/métodos , Estudos Transversais , Citocinas/metabolismo , Fibroblastos/metabolismo , Citometria de Fluxo , Expressão Gênica , Perfilação da Expressão Gênica/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Leucócitos/imunologia , Leucócitos/metabolismo , Monócitos/imunologia , Monócitos/metabolismo , Transdução de Sinais , Análise de Célula Única/métodos , Membrana Sinovial/patologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Fluxo de TrabalhoRESUMO
Systemic lupus erythematosus (SLE) is prototypical autoimmune disease driven by pathological T cell-B cell interactions1,2. Expansion of T follicular helper (TFH) and T peripheral helper (TPH) cells, two T cell populations that provide help to B cells, is a prominent feature of SLE3,4. Human TFH and TPH cells characteristically produce high levels of the B cell chemoattractant CXCL13 (refs. 5,6), yet regulation of T cell CXCL13 production and the relationship between CXCL13+ T cells and other T cell states remains unclear. Here, we identify an imbalance in CD4+ T cell phenotypes in patients with SLE, with expansion of PD-1+/ICOS+ CXCL13+ T cells and reduction of CD96hi IL-22+ T cells. Using CRISPR screens, we identify the aryl hydrocarbon receptor (AHR) as a potent negative regulator of CXCL13 production by human CD4+ T cells. Transcriptomic, epigenetic and functional studies demonstrate that AHR coordinates with AP-1 family member JUN to prevent CXCL13+ TPH/TFH cell differentiation and promote an IL-22+ phenotype. Type I interferon, a pathogenic driver of SLE7, opposes AHR and JUN to promote T cell production of CXCL13. These results place CXCL13+ TPH/TFH cells on a polarization axis opposite from T helper 22 (TH22) cells and reveal AHR, JUN and interferon as key regulators of these divergent T cell states.
Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos , Linfócitos T CD4-Positivos , Quimiocina CXCL13 , Interferon Tipo I , Lúpus Eritematoso Sistêmico , Proteínas Proto-Oncogênicas c-jun , Receptores de Hidrocarboneto Arílico , Feminino , Humanos , Masculino , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Diferenciação Celular , Quimiocina CXCL13/metabolismo , Epigenômica , Perfilação da Expressão Gênica , Interferon Tipo I/imunologia , Interferon Tipo I/metabolismo , Interleucina 22/imunologia , Interleucina 22/metabolismo , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/metabolismo , Lúpus Eritematoso Sistêmico/genética , Proteínas Proto-Oncogênicas c-jun/metabolismo , Receptores de Hidrocarboneto Arílico/metabolismo , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/metabolismoRESUMO
OBJECTIVE: Autoantibodies and autoimmune diseases after SARS-CoV-2 infection are widely reported. Given evolving variants, milder infections, and increasing population vaccination, we hypothesized that SARS-CoV-2 infection earlier in the pandemic would be associated with more autoimmune connective tissue disease (CTD) symptoms and immunologic abnormalities. METHODS: Patients ≥18 years old with COVID-19 3/1/2020-8/15/2022 completed the CTD Screening Questionnaire and were tested for 27 autoimmune serologies, SARS-CoV-2 serologies, cell-bound complement activation products (CB-CAPs), and T and B lymphocyte immunophenotypes by flow cytometry. We assessed relationships between symptoms, serologies, and immunophenotypes in earlier (3/1/2020-1/31/2021) vs. later (2/1/2021-8/15/2022) periods, with different predominating SARS-CoV-2 viruses. RESULTS: 57 subjects had earlier and 23 had later pandemic COVID-19. 35 % of earlier vs. 17 % of later pandemic patients had CTD symptoms (p 0.18). More patients were antinuclear antibody (ANA) positive (44 % vs. 13 %, p 0.01) and had lupus anticoagulant (11 % vs. 4 %, p 0.67). After adjustment for age, race, and sex, earlier (vs. later) COVID-19 was associated with increased ANA positivity (OR 4.60, 95%CI 1.17, 18.15). No subjects had positive CB-CAPs. T and B cell immunophenotypes and SARS-CoV-2 serologies did not differ by group. In heatmap analyses, higher autoantibody variety was seen among those with infection in the early pandemic. CONCLUSION: In this sample, having COVID-19 infection in the earlier (pre-2/1/2021) vs. later pandemic was associated with more CTD symptoms, ANA positivity, and autoantibody reactivities. Earlier SARS-CoV-2 variants circulating in a less vaccinated population with less natural immunity may have been more immunogenic.
RESUMO
OBJECTIVE: To determine the incidence and baseline factors associated with breakthrough coronavirus disease 2019 (COVID-19) after preexposure prophylaxis (PrEP) with tixagevimab/cilgavimab among patients with systemic autoimmune rheumatic diseases (SARDs). METHODS: We performed a retrospective cohort study among patients with SARDs who received tixagevimab/cilgavimab between January 2, 2022, and November 16, 2022. The primary outcome was breakthrough COVID-19 after tixagevimab/cilgavimab. We performed multivariable Cox regression models adjusted for baseline factors to identify risk factors for breakthrough COVID-19. RESULTS: We identified 444 patients with SARDs who received tixagevimab/cilgavimab (mean age 62.0 years, 78.2% female). There were 83 (18.7%) breakthrough COVID-19 cases (incidence rate 31.5/1000 person-months, 95% CI 24.70-38.24), 7 (1.6%) hospitalizations, and 1 (0.2%) death. Older age was inversely associated with breakthrough COVID-19 (adjusted hazard ratio [aHR] 0.86/10 years, 95% CI 0.75-0.99). Higher baseline spike antibody levels were associated with lower risk of breakthrough COVID-19 (aHR 0.42, 95% CI 0.18-0.99 for spike antibody levels > 200 vs < 0.4 units). CD20 inhibitor users had a similar risk of breakthrough COVID-19 (aHR 1.05, 95% CI 0.44-2.49) compared to conventional synthetic disease-modifying antirheumatic drug (DMARD) users. CONCLUSION: We found that patients with SARDs had frequent breakthrough COVID-19, but the proportion experiencing severe COVID-19 was low. DMARD type, including CD20 inhibitors, did not significantly affect risk of breakthrough COVID-19. Evidence of prior humoral immunity was protective against breakthrough infection, highlighting the continued need for a multimodal approach to prevent severe COVID-19 as novel PrEP therapies are being developed.
Assuntos
Anticorpos Monoclonais , Antirreumáticos , COVID-19 , Doenças Reumáticas , Humanos , Feminino , Pessoa de Meia-Idade , Masculino , Estudos Retrospectivos , Antirreumáticos/uso terapêutico , Doenças Reumáticas/complicações , Doenças Reumáticas/tratamento farmacológicoRESUMO
SerpinB1, a protease inhibitor and neutrophil survival factor, was recently linked with IL-17-expressing T cells. Here, we show that serpinB1 (Sb1) is dramatically induced in a subset of effector CD4 cells in experimental autoimmune encephalomyelitis (EAE). Despite normal T cell priming, Sb1-/- mice are resistant to EAE with a paucity of T helper (TH) cells that produce two or more of the cytokines, IFNγ, GM-CSF, and IL-17. These multiple cytokine-producing CD4 cells proliferate extremely rapidly; highly express the cytolytic granule proteins perforin-A, granzyme C (GzmC), and GzmA and surface receptors IL-23R, IL-7Rα, and IL-1R1; and can be identified by the surface marker CXCR6. In Sb1-/- mice, CXCR6+ TH cells are generated but fail to expand due to enhanced granule protease-mediated mitochondrial damage leading to suicidal cell death. Finally, anti-CXCR6 antibody treatment, like Sb1 deletion, dramatically reverts EAE, strongly indicating that the CXCR6+ T cells are the drivers of encephalitis.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Encefalomielite Autoimune Experimental/patologia , Receptores CXCR6/metabolismo , Serpinas/fisiologia , Linfócitos T Auxiliares-Indutores/imunologia , Animais , Citocinas/metabolismo , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/metabolismo , Interferon gama/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores CXCR6/genéticaRESUMO
More than 1 million apheresis platelet collections are performed annually in the United States. After 2 healthy plateletpheresis donors were incidentally found to have low CD4+ T-lymphocyte counts, we investigated whether plateletpheresis causes lymphopenia. We conducted a cross-sectional single-center study of platelet donors undergoing plateletpheresis with the Trima Accel, which removes leukocytes continuously with its leukoreduction system chamber. We recruited 3 groups of platelet donors based on the total number of plateletpheresis sessions in the prior 365 days: 1 or 2, 3 to 19, or 20 to 24. CD4+ T-lymphocyte counts were <200 cells per microliter in 0/20, 2/20, and 6/20 donors, respectively (P = .019), and CD8+ T-lymphocyte counts were low in 0/20, 4/20, and 11/20 donors, respectively (P < .001). The leukoreduction system chamber's lymphocyte-extraction efficiency was â¼15% to 20% for all groups. Immunophenotyping showed decreases in naive CD4+ T-lymphocyte and T helper 17 (Th17) cell percentages, increases in CD4+ and CD8+ effector memory, Th1, and regulatory T cell percentages, and stable naive CD8+ and Th2 percentages across groups. T-cell receptor repertoire analyses showed similar clonal diversity in all groups. Donor screening questionnaires supported the good health of the donors, who tested negative at each donation for multiple pathogens, including HIV. Frequent plateletpheresis utilizing a leukoreduction system chamber is associated with CD4+ and CD8+ T-cell lymphopenia in healthy platelet donors. The mechanism may be repeated extraction of these cells during plateletpheresis. The cytopenias do not appear to be harmful.
Assuntos
Doadores de Sangue/estatística & dados numéricos , Plaquetas/citologia , Linfopenia/etiologia , Plaquetoferese/efeitos adversos , Adulto , Idoso , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Contagem de Plaquetas , Prognóstico , Adulto JovemRESUMO
Mouse natural killer (NK) cells acquire effector function by an education process termed "licensing" mediated by inhibitory Ly49 receptors which recognize self-MHC class I. Ly49 receptors can bind to MHC class I on targets (in trans) and also to MHC class I on the NK-cell surface (in cis). Which of these interactions regulates NK-cell licensing is not yet clear. Moreover, there are no clear phenotypic differences between licensed and unlicensed NK cells, perhaps because of the previously limited ability to study NK cells with synchronized licensing. Here, we produced MHC class I-deficient mice with inducible MHC class I consisting of a single-chain trimer (SCT), ovalbumin peptide-ß2 microgloblin-H2K(b) (SCT-K(b)). Only NK cells with a Ly49 receptor with specificity for SCT-K(b) were licensed after MHC class I induction. NK cells were localized consistently in red pulp of the spleen during induced NK-cell licensing, and there were no differences in maturation or activation markers on recently licensed NK cells. Although MHC class I-deficient NK cells were licensed in hosts following SCT-K(b) induction, NK cells were not licensed after induced SCT-K(b) expression on NK cells themselves in MHC class I-deficient hosts. Furthermore, hematopoietic cells with induced SCT-K(b) licensed NK cells more efficiently than stromal cells. These data indicate that trans interaction with MHC class I on hematopoietic cells regulates NK-cell licensing, which is not associated with other obvious phenotypic changes.
Assuntos
Antígenos de Histocompatibilidade Classe I/metabolismo , Células Matadoras Naturais/imunologia , Ativação Linfocitária/imunologia , Subfamília A de Receptores Semelhantes a Lectina de Células NK/metabolismo , Receptores de Células Matadoras Naturais/metabolismo , Transferência Adotiva , Animais , Células-Tronco Hematopoéticas/imunologia , Células-Tronco Hematopoéticas/metabolismo , Antígenos de Histocompatibilidade Classe I/imunologia , Imuno-Histoquímica , Células Matadoras Naturais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Receptores de Células Matadoras Naturais/imunologia , Baço/metabolismoRESUMO
Natural killer (NK) cells have important functions in cancer immunosurveillance, BM allograft rejection, fighting infections, tissue homeostasis, and reproduction. NK cell-based therapies are promising treatments for blood cancers. Overcoming their currently limited efficacy requires a better understanding of the molecular mechanisms controlling NK cell development and dampening their effector functions. NK cells recognize the loss of self-antigens or up-regulation of stress-induced ligands on pathogen-infected or tumor cells through invariant NK cell receptors (NKRs), and then kill such stressed cells. Two second-messenger pathways downstream of NKRs are required for NK cell maturation and effector responses: PIP(3) generation by PI3K and generation of diacylglycerol and IP(3) by phospholipase-Cγ (PLCγ). In the present study, we identify a novel role for the phosphorylated IP(3) metabolite inositol (1,3,4,5)tetrakisphosphate (IP(4)) in NK cells. IP(4) promotes NK cell terminal differentiation and acquisition of a mature NKR repertoire. However, in mature NK cells, IP(4) limits NKR-induced IFNγ secretion, granule exocytosis, and target-cell killing, in part by inhibiting the PIP(3) effector-kinase Akt. This identifies IP(4) as an important novel regulator of NK cell development and function and expands our understanding of the therapeutically important mechanisms dampening NK cell responses. Our results further suggest that PI3K regulation by soluble IP(4) is a broadly important signaling paradigm.
Assuntos
Fosfatos de Inositol/imunologia , Células Matadoras Naturais/imunologia , Ativação Linfocitária/imunologia , Fosfatidilinositol 3-Quinases/imunologia , Transdução de Sinais/imunologia , Animais , Fosfatos de Inositol/metabolismo , Células Matadoras Naturais/metabolismo , Camundongos , Camundongos Knockout , Fosfatidilinositol 3-Quinases/metabolismo , Receptores Citoplasmáticos e Nucleares/imunologia , Receptores Citoplasmáticos e Nucleares/metabolismoRESUMO
Granzymes are a family of serine proteases mainly expressed by CD8+ T cells, natural killer cells, and innate-like lymphocytes1,2. Although their major role is thought to be the induction of cell death in virally infected and tumor cells, accumulating evidence suggests some granzymes can regulate inflammation by acting on extracellular substrates2. Recently, we found that the majority of tissue CD8+ T cells in rheumatoid arthritis (RA) synovium, inflammatory bowel disease and other inflamed organs express granzyme K (GZMK)3, a tryptase-like protease with poorly defined function. Here, we show that GZMK can activate the complement cascade by cleaving C2 and C4. The nascent C4b and C2a fragments form a C3 convertase that cleaves C3, allowing further assembly of a C5 convertase that cleaves C5. The resulting convertases trigger every major event in the complement cascade, generating the anaphylatoxins C3a and C5a, the opsonins C4b and C3b, and the membrane attack complex. In RA synovium, GZMK is enriched in areas with abundant complement activation, and fibroblasts are the major producers of complement C2, C3, and C4 that serve as targets for GZMK-mediated complement activation. Our findings describe a previously unidentified pathway of complement activation that is entirely driven by lymphocyte-derived GZMK and proceeds independently of the classical, lectin, or alternative pathways. Given the widespread abundance of GZMK-expressing T cells in tissues in chronic inflammatory diseases and infection, GZMK-mediated complement activation is likely to be an important contributor to tissue inflammation in multiple disease contexts.
RESUMO
OBJECTIVE: Disease-modifying anti-rheumatic drugs (DMARDs) that treat rheumatoid arthritis (RA) may reduce immune responses to COVID-19 vaccination. We compared humoral and cell-mediated immunity before and after a 3rd dose of mRNA COVID vaccine in RA subjects. METHODS: RA patients that received 2 doses of mRNA vaccine enrolled in an observational study in 2021 before receiving a 3rd dose. Subjects self-reported holding or continuing DMARDs. Blood samples were collected pre- and 4 weeks after the 3rd dose. 50 healthy controls provided blood samples. Humoral response was measured with in-house ELISA assays for anti-Spike IgG (anti-S) and anti-receptor binding domain IgG (anti-RBD). T cell activation was measured after stimulation with SARS-CoV-2 peptide. Spearman's correlations assessed the relationship between anti-S, anti-RBD, and frequencies of activated T cells. RESULTS: Among 60 subjects, mean age was 63 years and 88% were female. 57% of subjects held at least 1 DMARD around the 3rd dose. 43% (anti-S) and 62% (anti-RBD) had a normal humoral response at week 4, defined as ELISA within 1 standard deviation of the healthy control mean. No differences in antibody levels were observed based on holding DMARDs. Median frequency of activated CD4 T cells was significantly greater post- vs. pre-3rd dose. Changes in antibody levels did not correlate with change in frequency of activated CD4 T cells. CONCLUSION: Virus-specific IgG levels significantly increased in RA subjects using DMARDs after completing the primary vaccine series, though fewer than two-thirds achieved a humoral response like healthy controls. Humoral and cellular changes were not correlated.
Assuntos
Antirreumáticos , Artrite Reumatoide , COVID-19 , Humanos , Feminino , Pessoa de Meia-Idade , Masculino , Vacinas contra COVID-19 , SARS-CoV-2 , Imunidade Celular , RNA Mensageiro , Imunoglobulina GRESUMO
Immune checkpoint inhibitor (ICI) therapies used to treat cancer, such as anti-PD-1 antibodies, can induce autoimmune conditions in some individuals. The T cell mechanisms mediating such iatrogenic autoimmunity and their overlap with spontaneous autoimmune diseases remain unclear. Here, we compared T cells from the joints of 20 patients with an inflammatory arthritis induced by ICI therapy (ICI-arthritis) with two archetypal autoimmune arthritides, rheumatoid arthritis (RA) and psoriatic arthritis (PsA). Single-cell transcriptomic and antigen receptor repertoire analyses highlighted clonal expansion of an activated effector CD8 T cell population in the joints and blood of patients with ICI-arthritis. These cells were identified as CD38hiCD127- CD8 T cells and were uniquely enriched in ICI-arthritis joints compared with RA and PsA and also displayed an elevated interferon signature. In vitro, type I interferon induced CD8 T cells to acquire the ICI-associated CD38hi phenotype and enhanced cytotoxic function. In a cohort of patients with advanced melanoma, ICI therapy markedly expanded circulating CD38hiCD127- T cells, which were frequently bound by the therapeutic anti-PD-1 drug. In patients with ICI-arthritis, drug-bound CD8 T cells in circulation showed marked clonal overlap with drug-bound CD8 T cells from synovial fluid. These results suggest that ICI therapy directly targets CD8 T cells in patients who develop ICI-arthritis and induces an autoimmune pathology that is distinct from prototypical spontaneous autoimmune arthritides.
Assuntos
Artrite Psoriásica , Artrite Reumatoide , Linfócitos T CD8-Positivos , Humanos , Artrite Psoriásica/metabolismo , Líquido Sinovial/metabolismo , Linfócitos T Citotóxicos/metabolismoRESUMO
Rheumatoid arthritis (RA) is an autoimmune disease initiated by antigen-specific T cells and B cells, which promote synovial inflammation through a complex set of interactions with innate immune and stromal cells. To better understand the phenotypes and clonal relationships of synovial T and B cells, we performed single-cell RNA and repertoire sequencing on paired synovial tissue and peripheral blood samples from 12 donors with seropositive RA ranging from early to chronic disease. Paired transcriptomic-repertoire analyses highlighted 3 clonally distinct CD4 T cells populations that were enriched in RA synovium: T peripheral helper (Tph) and T follicular helper (Tfh) cells, CCL5+ T cells, and T regulatory cells (Tregs). Among these cells, Tph cells showed a unique transcriptomic signature of recent T cell receptor (TCR) activation, and clonally expanded Tph cells expressed an elevated transcriptomic effector signature compared to non-expanded Tph cells. CD8 T cells showed higher oligoclonality than CD4 T cells, and the largest CD8 T cell clones in synovium were highly enriched in GZMK+ cells. TCR analyses revealed CD8 T cells with likely viral-reactive TCRs distributed across transcriptomic clusters and definitively identified MAIT cells in synovium, which showed transcriptomic features of TCR activation. Among B cells, non-naive B cells including age-associated B cells (ABC), NR4A1+ activated B cells, and plasma cells, were enriched in synovium and had higher somatic hypermutation rates compared to blood B cells. Synovial B cells demonstrated substantial clonal expansion, with ABC, memory, and activated B cells clonally linked to synovial plasma cells. Together, these results reveal clonal relationships between functionally distinct lymphocyte populations that infiltrate RA synovium.
RESUMO
NK cells are innate immune lymphocytes that can react to cells lacking self-MHC class I. However, NK cells that cannot engage self-MHC through an inhibitory receptor are resistant to stimulation through their activation receptors. To become licensed (i.e., functionally competent to be triggered through its activation receptors), an NK cell must engage host MHC class I via a MHC class I-specific inhibitory receptor, such as a member of the murine Ly49 family. To explore potential determinants of NK cell licensing on a single Ly49 receptor, we have investigated the relative licensing impacts of the b, d, k, q, r, and s H2 haplotypes on Ly49A(+) NK cells. The results indicate that licensing is essentially analog but is saturated by moderate-binding MHC class I ligands. Interestingly, licensing exhibited a strong inverse correlation with a measure of cis engagement of Ly49A. Finally, licensing of Ly49A(+) NK cells was found to be less sensitive to MHC class I engagement than Ly49A-mediated effector inhibition, suggesting that licensing establishes a margin of safety against NK cell autoreactivity.
Assuntos
Citotoxicidade Imunológica/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Células Matadoras Naturais/imunologia , Ativação Linfocitária/imunologia , Subfamília A de Receptores Semelhantes a Lectina de Células NK/imunologia , Alelos , Animais , Separação Celular , Citometria de Fluxo , Haplótipos , Antígenos de Histocompatibilidade Classe I/genética , Ativação Linfocitária/genética , Camundongos , Camundongos TransgênicosRESUMO
Macrophages regulate protective immune responses to infectious microbes, but aberrant macrophage activation frequently drives pathological inflammation. To identify regulators of vigorous macrophage activation, we analyzed RNA-seq data from synovial macrophages and identified SLAMF7 as a receptor associated with a superactivated macrophage state in rheumatoid arthritis. We implicated IFN-γ as a key regulator of SLAMF7 expression and engaging SLAMF7 drove a strong wave of inflammatory cytokine expression. Induction of TNF-α after SLAMF7 engagement amplified inflammation through an autocrine signaling loop. We observed SLAMF7-induced gene programs not only in macrophages from rheumatoid arthritis patients but also in gut macrophages from patients with active Crohn's disease and in lung macrophages from patients with severe COVID-19. This suggests a central role for SLAMF7 in macrophage superactivation with broad implications in human disease pathology.
Assuntos
Inflamação/imunologia , Ativação de Macrófagos/imunologia , Família de Moléculas de Sinalização da Ativação Linfocitária/imunologia , Transcriptoma/imunologia , Doença Aguda , Adulto , Artrite Reumatoide/genética , Artrite Reumatoide/imunologia , Artrite Reumatoide/metabolismo , COVID-19/genética , COVID-19/imunologia , COVID-19/metabolismo , COVID-19/virologia , Células Cultivadas , Doença Crônica , Doença de Crohn/genética , Doença de Crohn/imunologia , Doença de Crohn/metabolismo , Feminino , Humanos , Inflamação/genética , Inflamação/metabolismo , Ativação de Macrófagos/genética , RNA-Seq/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , SARS-CoV-2/imunologia , SARS-CoV-2/fisiologia , Família de Moléculas de Sinalização da Ativação Linfocitária/genética , Família de Moléculas de Sinalização da Ativação Linfocitária/metabolismo , Análise de Célula Única/métodos , Membrana Sinovial/imunologia , Membrana Sinovial/metabolismo , Membrana Sinovial/patologia , Transcriptoma/genéticaRESUMO
T cell-derived pro-inflammatory cytokines are a major driver of rheumatoid arthritis (RA) pathogenesis. Although these cytokines have traditionally been attributed to CD4 T cells, we have found that CD8 T cells are notably abundant in synovium and make more interferon (IFN)-γ and nearly as much tumor necrosis factor (TNF) as their CD4 T cell counterparts. Furthermore, using unbiased high-dimensional single-cell RNA-seq and flow cytometric data, we found that the vast majority of synovial tissue and synovial fluid CD8 T cells belong to an effector CD8 T cell population characterized by high expression of granzyme K (GzmK) and low expression of granzyme B (GzmB) and perforin. Functional experiments demonstrate that these GzmK+ GzmB+ CD8 T cells are major cytokine producers with low cytotoxic potential. Using T cell receptor repertoire data, we found that CD8 GzmK+ GzmB+ T cells are clonally expanded in synovial tissues and maintain their granzyme expression and overall cell state in blood, suggesting that they are enriched in tissue but also circulate. Using GzmK and GzmB signatures, we found that GzmK-expressing CD8 T cells were also the major CD8 T cell population in the gut, kidney, and coronavirus disease 2019 (COVID-19) bronchoalveolar lavage fluid, suggesting that they form a core population of tissue-associated T cells across diseases and human tissues. We term this population tissue-enriched expressing GzmK or TteK CD8 cells. Armed to produce cytokines in response to both antigen-dependent and antigen-independent stimuli, CD8 TteK cells have the potential to drive inflammation.