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Mitochondrial abnormalities have been noted in lupus, but the causes and consequences remain obscure. Autophagy-related genes ATG5, ATG7 and IRGM have been previously implicated in autoimmune disease. We reasoned that failure to clear defective mitochondria via mitophagy might be a foundational driver in autoimmunity by licensing mitochondrial DNA-dependent induction of type I interferon. Here, we show that mice lacking the GTPase IRGM1 (IRGM homolog) exhibited a type I interferonopathy with autoimmune features. Irgm1 deletion impaired the execution of mitophagy with cell-specific consequences. In fibroblasts, mitochondrial DNA soiling of the cytosol induced cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING)-dependent type I interferon, whereas in macrophages, lysosomal Toll-like receptor 7 was activated. In vivo, Irgm1-/- tissues exhibited mosaic dependency upon nucleic acid receptors. Whereas salivary and lacrimal gland autoimmune pathology was abolished and lung pathology was attenuated by cGAS and STING deletion, pancreatic pathology remained unchanged. These findings reveal fundamental connections between mitochondrial quality control and tissue-selective autoimmune disease.
Assuntos
Doenças Autoimunes/metabolismo , Autoimunidade , Fibroblastos/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Mitocôndrias/metabolismo , Mitofagia , Animais , Doenças Autoimunes/genética , Doenças Autoimunes/imunologia , Doenças Autoimunes/patologia , Células Cultivadas , Fibroblastos/imunologia , Fibroblastos/patologia , Proteínas de Ligação ao GTP/deficiência , Proteínas de Ligação ao GTP/genética , Regulação da Expressão Gênica , Macrófagos/imunologia , Macrófagos/metabolismo , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , Mitocôndrias/genética , Mitocôndrias/imunologia , Mitocôndrias/patologia , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , Transdução de Sinais , Receptor 7 Toll-Like/genética , Receptor 7 Toll-Like/metabolismoRESUMO
Many infections, including malaria, are associated with an increase in autoantibodies (AAbs). Prior studies have reported an association between genetic markers of susceptibility to autoimmune disease and resistance to malaria, but the underlying mechanisms are unclear. Here, we performed a longitudinal study of children and adults (n = 602) in Mali and found that high levels of plasma AAbs before the malaria season independently predicted a reduced risk of clinical malaria in children during the ensuing malaria season. Baseline AAb seroprevalence increased with age and asymptomatic Plasmodium falciparum infection. We found that AAbs purified from the plasma of protected individuals inhibit the growth of blood-stage parasites and bind P. falciparum proteins that mediate parasite invasion. Protected individuals had higher plasma immunoglobulin G (IgG) reactivity against 33 of the 123 antigens assessed in an autoantigen microarray. This study provides evidence in support of the hypothesis that a propensity toward autoimmunity offers a survival advantage against malaria.
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A contribution of epigenetic modifications to B cell tolerance has been proposed but not directly tested. Here we report that deficiency of ten-eleven translocation (Tet) DNA demethylase family members Tet2 and Tet3 in B cells led to hyperactivation of B and T cells, autoantibody production and lupus-like disease in mice. Mechanistically, in the absence of Tet2 and Tet3, downregulation of CD86, which normally occurs following chronic exposure of self-reactive B cells to self-antigen, did not take place. The importance of dysregulated CD86 expression in Tet2- and Tet3-deficient B cells was further demonstrated by the restriction, albeit not complete, on aberrant T and B cell activation following anti-CD86 blockade. Tet2- and Tet3-deficient B cells had decreased accumulation of histone deacetylase 1 (HDAC1) and HDAC2 at the Cd86 locus. Thus, our findings suggest that Tet2- and Tet3-mediated chromatin modification participates in repression of CD86 on chronically stimulated self-reactive B cells, which contributes, at least in part, to preventing autoimmunity.
Assuntos
Autoimunidade/imunologia , Linfócitos B/imunologia , Antígeno B7-2/imunologia , Proteínas de Ligação a DNA/imunologia , Dioxigenases/imunologia , Proteínas Proto-Oncogênicas/imunologia , Animais , Doenças Autoimunes/imunologia , Epigênese Genética/imunologia , Ativação Linfocitária/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos TransgênicosRESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
Gain-of-function mutations in the gene encoding the phosphatidylinositol-3-OH kinase catalytic subunit p110δ (PI3Kδ) result in a human primary immunodeficiency characterized by lymphoproliferation, respiratory infections and inefficient responses to vaccines. However, what promotes these immunological disturbances at the cellular and molecular level remains unknown. We generated a mouse model that recapitulated major features of this disease and used this model and patient samples to probe how hyperactive PI3Kδ fosters aberrant humoral immunity. We found that mutant PI3Kδ led to co-stimulatory receptor ICOS-independent increases in the abundance of follicular helper T cells (TFH cells) and germinal-center (GC) B cells, disorganized GCs and poor class-switched antigen-specific responses to immunization, associated with altered regulation of the transcription factor FOXO1 and pro-apoptotic and anti-apoptotic members of the BCL-2 family. Notably, aberrant responses were accompanied by increased reactivity to gut bacteria and a broad increase in autoantibodies that were dependent on stimulation by commensal microbes. Our findings suggest that proper regulation of PI3Kδ is critical for ensuring optimal host-protective humoral immunity despite tonic stimulation from the commensal microbiome.
Assuntos
Linfócitos B/fisiologia , Microbioma Gastrointestinal/imunologia , Centro Germinativo/fisiologia , Mutação/genética , Fosfatidilinositol 3-Quinases/genética , Linfócitos T Auxiliares-Indutores/fisiologia , Animais , Autoanticorpos/sangue , Células Cultivadas , Classe I de Fosfatidilinositol 3-Quinases/genética , Modelos Animais de Doenças , Proteína Forkhead Box O1/genética , Proteína Forkhead Box O1/metabolismo , Humanos , Imunidade Humoral/genética , Switching de Imunoglobulina/genética , Síndromes de Imunodeficiência/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismoRESUMO
The adaptor CARD9 functions downstream of C-type lectin receptors (CLRs) for the sensing of microbial infection, which leads to responses by the TH1 and TH17 subsets of helper T cells. The single-nucleotide polymorphism rs4077515 at CARD9 in the human genome, which results in the substitution S12N (CARD9S12N), is associated with several autoimmune diseases. However, the function of CARD9S12N has remained unknown. Here we generated CARD9S12N knock-in mice and found that CARD9S12N facilitated the induction of type 2 immune responses after engagement of CLRs. Mechanistically, CARD9S12N mediated CLR-induced activation of the non-canonical transcription factor NF-κB subunit RelB, which initiated production of the cytokine IL-5 in alveolar macrophages for the recruitment of eosinophils to drive TH2 cell-mediated allergic responses. We identified the homozygous CARD9 mutation encoding S12N in patients with allergic bronchopulmonary aspergillosis and revealed activation of RelB and production of IL-5 in peripheral blood mononuclear cells from these patients. Our study provides genetic and functional evidence demonstrating that CARD9S12N can turn alveolar macrophages into IL-5-producing cells and facilitates TH2 cell-mediated pathologic responses.
Assuntos
Aspergilose Broncopulmonar Alérgica/imunologia , Proteínas Adaptadoras de Sinalização CARD/imunologia , Interleucina-5/biossíntese , Macrófagos Alveolares/imunologia , Células Th2/imunologia , Animais , Aspergilose Broncopulmonar Alérgica/genética , Proteínas Adaptadoras de Sinalização CARD/genética , Humanos , Interleucina-5/imunologia , Macrófagos Alveolares/metabolismo , Camundongos , Polimorfismo de Nucleotídeo Único , Transdução de Sinais/imunologiaRESUMO
The mechanisms by which regulatory T (Treg) cells differentially control allergic and autoimmune responses remain unclear. We show that Treg cells in food allergy (FA) had decreased expression of transforming growth factor beta 1 (TGF-ß1) because of interleukin-4 (IL-4)- and signal transducer and activator of transciription-6 (STAT6)-dependent inhibition of Tgfb1 transcription. These changes were modeled by Treg cell-specific Tgfb1 monoallelic inactivation, which induced allergic dysregulation by impairing microbiota-dependent retinoic acid receptor-related orphan receptor gamma t (ROR-γt)+ Treg cell differentiation. This dysregulation was rescued by treatment with Clostridiales species, which upregulated Tgfb1 expression in Treg cells. Biallelic deficiency precipitated fatal autoimmunity with intense autoantibody production and dysregulated T follicular helper and B cell responses. These results identify a privileged role of Treg cell-derived TGF-ß1 in regulating allergy and autoimmunity at distinct checkpoints in a Tgfb1 gene dose- and microbiota-dependent manner.
Assuntos
Autoimunidade/imunologia , Hipersensibilidade/imunologia , Linfócitos T Reguladores/imunologia , Fator de Crescimento Transformador beta1/imunologia , Adolescente , Animais , Autoimunidade/genética , Linfócitos B/imunologia , Diferenciação Celular , Criança , Pré-Escolar , Hipersensibilidade Alimentar/imunologia , Dosagem de Genes , Humanos , Hipersensibilidade/genética , Imunoglobulina G/imunologia , Lactente , Mastócitos/imunologia , Camundongos , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , Células T Auxiliares Foliculares/imunologia , Linfócitos T Reguladores/metabolismo , Transcrição Gênica , Fator de Crescimento Transformador beta1/genética , Adulto JovemRESUMO
While a mutation in C9ORF72 is the most common genetic contributor to amyotrophic lateral sclerosis (ALS), much remains to be learned concerning the function of the protein normally encoded at this locus. To elaborate further on functions for C9ORF72, we used quantitative mass spectrometry-based proteomics to identify interacting proteins in motor neurons and found that its long isoform complexes with and stabilizes SMCR8, which further enables interaction with WDR41. To study the organismal and cellular functions for this tripartite complex, we generated Smcr8 loss-of-function mutant mice and found that they developed phenotypes also observed in C9orf72 loss-of-function animals, including autoimmunity. Along with a loss of tolerance for many nervous system autoantigens, we found increased lysosomal exocytosis in Smcr8 mutant macrophages. In addition to elevated surface Lamp1 (lysosome-associated membrane protein 1) expression, we also observed enhanced secretion of lysosomal components-phenotypes that we subsequently observed in C9orf72 loss-of-function macrophages. Overall, our findings demonstrate that C9ORF72 and SMCR8 have interdependent functions in suppressing autoimmunity as well as negatively regulating lysosomal exocytosis-processes of potential importance to ALS.
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Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/fisiopatologia , Autoimunidade/genética , Proteínas de Transporte/metabolismo , Exocitose/genética , Lisossomos/metabolismo , Animais , Proteína C9orf72/genética , Proteína C9orf72/metabolismo , Proteínas de Transporte/genética , Regulação da Expressão Gênica/genética , Humanos , Linfonodos/patologia , Proteína 1 de Membrana Associada ao Lisossomo/genética , Macrófagos/patologia , Camundongos , Camundongos Knockout , Mutação , Isoformas de Proteínas , Estabilidade Proteica , Esplenomegalia/genéticaRESUMO
Wiskott-Aldrich syndrome (WAS) is a rare X-linked disorder characterized by combined immunodeficiency, eczema, microthrombocytopenia, autoimmunity, and lymphoid malignancies. Gene therapy (GT) to modify autologous CD34+ cells is an emerging alternative treatment with advantages over standard allogeneic hematopoietic stem cell transplantation for patients who lack well-matched donors, avoiding graft-versus-host-disease. We report the outcomes of a phase 1/2 clinical trial in which 5 patients with severe WAS underwent GT using a self-inactivating lentiviral vector expressing the human WAS complementary DNA under the control of a 1.6-kB fragment of the autologous promoter after busulfan and fludarabine conditioning. All patients were alive and well with sustained multilineage vector gene marking (median follow-up: 7.6 years). Clinical improvement of eczema, infections, and bleeding diathesis was universal. Immune function was consistently improved despite subphysiologic levels of transgenic WAS protein expression. Improvements in platelet count and cytoskeletal function in myeloid cells were most prominent in patients with high vector copy number in the transduced product. Two patients with a history of autoimmunity had flares of autoimmunity after GT, despite similar percentages of WAS protein-expressing cells and gene marking to those without autoimmunity. Patients with flares of autoimmunity demonstrated poor numerical recovery of T cells and regulatory T cells (Tregs), interleukin-10-producing regulatory B cells (Bregs), and transitional B cells. Thus, recovery of the Breg compartment, along with Tregs appears to be protective against development of autoimmunity after GT. These results indicate that clinical and laboratory manifestations of WAS are improved with GT with an acceptable safety profile. This trial is registered at clinicaltrials.gov as #NCT01410825.
Assuntos
Eczema , Transplante de Células-Tronco Hematopoéticas , Síndrome de Wiskott-Aldrich , Humanos , Síndrome de Wiskott-Aldrich/genética , Síndrome de Wiskott-Aldrich/terapia , Proteína da Síndrome de Wiskott-Aldrich/genética , Células-Tronco Hematopoéticas/metabolismo , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Terapia Genética/métodos , Eczema/etiologia , Eczema/metabolismo , Eczema/terapiaRESUMO
Anoikis-Related Genes (ARGs) lead to the organism manifesting resistance to anoikis and are associated with unfavorable prognostic outcomes across various malignancies.Therefore, it is crucial to identify the pivotal target genes related to anoikis in HCC .We found that ARGs were significantly correlated with prognosis and immune responses in HCC. The core gene, SPP1, notably promoted anoikis resistance and metastasis in HCC through both in vivo and in vitro studies. The PI3K-Akt-mTOR pathway played a critical role in anoikis suppression within HCC contexts. Our research unveiled SPP1's role in enhancing PKCα phosphorylation, which in turn activated the PI3K-Akt-mTOR cascade. Additionally, SPP1 was identified as a key regulator of MDSCs and Tregs migration, directly affecting their immunosuppressive capabilities.These findings indicate that in HCC, SPP1 promoted anoikis resistance and facilitated immune evasion by modulating MDSCs and Tregs.
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TREX1 is an endoplasmic reticulum (ER)-associated negative regulator of innate immunity. TREX1 mutations are associated with autoimmune and autoinflammatory diseases. Biallelic mutations abrogating DNase activity cause autoimmunity by allowing immunogenic self-DNA to accumulate, but it is unknown how dominant frameshift (fs) mutations that encode DNase-active but mislocalized proteins cause disease. We found that the TREX1 C terminus suppressed immune activation by interacting with the ER oligosaccharyltransferase (OST) complex and stabilizing its catalytic integrity. C-terminal truncation of TREX1 by fs mutations dysregulated the OST complex, leading to free glycan release from dolichol carriers, as well as immune activation and autoantibody production. A connection between OST dysregulation and immune disorders was demonstrated in Trex1(-/-) mice, TREX1-V235fs patient lymphoblasts, and TREX1-V235fs knock-in mice. Inhibiting OST with aclacinomycin corrects the glycan and immune defects associated with Trex1 deficiency or fs mutation. This function of the TREX1 C terminus suggests a potential therapeutic option for TREX1-fs mutant-associated diseases.
Assuntos
Citosol/enzimologia , Exodesoxirribonucleases/metabolismo , Hexosiltransferases/metabolismo , Proteínas de Membrana/metabolismo , Fosfoproteínas/metabolismo , Aclarubicina/análogos & derivados , Aclarubicina/farmacologia , Animais , Células Cultivadas , Embrião de Mamíferos/citologia , Exodesoxirribonucleases/antagonistas & inibidores , Exodesoxirribonucleases/genética , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Mutação da Fase de Leitura , Células HEK293 , Células HeLa , Hexosiltransferases/genética , Humanos , Imunidade Inata/genética , Immunoblotting , Proteínas de Membrana/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Microscopia de Fluorescência , Fosfoproteínas/antagonistas & inibidores , Fosfoproteínas/genética , Polissacarídeos/metabolismo , Ligação Proteica , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Prostate cancer (PCa) is a common malignant cancer in elderly males in Western countries. Whole-genome sequencing confirmed that long non-coding RNAs (lncRNAs) are frequently altered in castration-resistant prostate cancer (CRPC) and promote drug resistance to cancer therapy. Therefore, elucidating the prospective role of lncRNAs in PCa oncogenesis and progression is of remarkable clinical significance. In this study, gene expression in prostate tissues was determined using RNA-sequencing datasets, and the gene diagnostic and prognostic values of CRPC were analyzed using bioinformatics. Further, the expression levels and clinical significance of MAGI2 Antisense RNA 3 (MAGI2-AS3) in PCa clinical specimens were evaluated. The tumor-suppressive activity of MAGI2-AS3 was functionally explored in PCa cell lines and animal xenograft models. MAGI2-AS3 was found to be aberrantly decreased in CRPC and was negatively correlated with Gleason score and lymph node status. Notably, low MAGI2-AS3 expression positively correlated with poorer survival in patients with PCa. The overexpression of MAGI2-AS3 significantly inhibited the proliferation and migration of PCa in vitro and in vivo. Mechanistically, MAGI2-AS3 could play a tumor suppressor function in CRPC through a novel miR-106a-5p/RAB31 regulatory network and could be a target for future cancer therapy.
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MicroRNAs , Neoplasias de Próstata Resistentes à Castração , RNA Longo não Codificante , Masculino , Animais , Humanos , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Neoplasias de Próstata Resistentes à Castração/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Prognóstico , Proliferação de Células/genética , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Proteínas rab de Ligação ao GTP/genética , Proteínas rab de Ligação ao GTP/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Guanilato Quinases/genética , Guanilato Quinases/metabolismoRESUMO
BACKGROUND & AIMS: There is a major unmet need to assess the prognostic impact of antifibrotics in clinical trials because of the slow rate of liver fibrosis progression. We aimed to develop a surrogate biomarker to predict future fibrosis progression. METHODS: A fibrosis progression signature (FPS) was defined to predict fibrosis progression within 5 years in patients with hepatitis C virus and nonalcoholic fatty liver disease (NAFLD) with no to minimal fibrosis at baseline (n = 421) and was validated in an independent NAFLD cohort (n = 78). The FPS was used to assess response to 13 candidate antifibrotics in organotypic ex vivo cultures of clinical fibrotic liver tissues (n = 78) and cenicriviroc in patients with nonalcoholic steatohepatitis enrolled in a clinical trial (n = 19, NCT02217475). A serum protein-based surrogate FPS was developed and tested in a cohort of compensated cirrhosis patients (n = 122). RESULTS: A 20-gene FPS was defined and validated in an independent NAFLD cohort (adjusted odds ratio, 10.93; area under the receiver operating characteristic curve, 0.86). Among computationally inferred fibrosis-driving FPS genes, BCL2 was confirmed as a potential pharmacologic target using clinical liver tissues. Systematic ex vivo evaluation of 13 candidate antifibrotics identified rational combination therapies based on epigallocatechin gallate, which were validated for enhanced antifibrotic effect in ex vivo culture of clinical liver tissues. In patients with nonalcoholic steatohepatitis treated with cenicriviroc, FPS modulation was associated with 1-year fibrosis improvement accompanied by suppression of the E2F pathway. Induction of the PPARα pathway was absent in patients without fibrosis improvement, suggesting a benefit of combining PPARα agonism to improve the antifibrotic efficacy of cenicriviroc. A 7-protein serum protein-based surrogate FPS was associated with the development of decompensation in cirrhosis patients. CONCLUSION: The FPS predicts long-term fibrosis progression in an etiology-agnostic manner, which can inform antifibrotic drug development.
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Hepatopatia Gordurosa não Alcoólica , Progressão da Doença , Desenvolvimento de Medicamentos , Fibrose , Humanos , Fígado/patologia , Cirrose Hepática/complicações , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/genética , PPAR alfa/genéticaRESUMO
BACKGROUND: Autoimmunity has been reported in patients with severe coronavirus disease 2019 (COVID-19). We investigated whether anti-nuclear/extractable-nuclear antibodies (ANAs/ENAs) were present up to a year after infection, and if they were associated with the development of clinically relevant post-acute sequalae of COVID-19 (PASC) symptoms. METHODS: A rapid-assessment line immunoassay was used to measure circulating levels of ANAs/ENAs in 106 convalescent COVID-19 patients with varying acute phase severities at 3, 6 and 12â months post-recovery. Patient-reported fatigue, cough and dyspnoea were recorded at each time point. Multivariable logistic regression model and receiver operating curves were used to test the association of autoantibodies with patient-reported outcomes and pro-inflammatory cytokines. RESULTS: Compared to age- and sex-matched healthy controls (n=22) and those who had other respiratory infections (n=34), patients with COVID-19 had higher detectable ANAs at 3â months post-recovery (p<0.001). The mean number of ANA autoreactivities per individual decreased between 3 and 12â months (from 3.99 to 1.55) with persistent positive titres associated with fatigue, dyspnoea and cough severity. Antibodies to U1-snRNP and anti-SS-B/La were both positively associated with persistent symptoms of fatigue (p<0.028, area under the curve (AUC) 0.86) and dyspnoea (p<0.003, AUC=0.81). Pro-inflammatory cytokines such as tumour necrosis factor (TNF)-α and C-reactive protein predicted the elevated ANAs at 12â months. TNF-α, D-dimer and interleukin-1ß had the strongest association with symptoms at 12â months. Regression analysis showed that TNF-α predicted fatigue (ß=4.65, p=0.004) and general symptomaticity (ß=2.40, p=0.03) at 12â months. INTERPRETATION: Persistently positive ANAs at 12â months post-COVID are associated with persisting symptoms and inflammation (TNF-α) in a subset of COVID-19 survivors. This finding indicates the need for further investigation into the role of autoimmunity in PASC.
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Autoanticorpos , COVID-19 , Humanos , Síndrome de COVID-19 Pós-Aguda , Fator de Necrose Tumoral alfa , Tosse , Anticorpos Antinucleares , Citocinas , FadigaRESUMO
Cognate interactions between autoreactive B and T cells promote systemic lupus erythematosus pathogenesis by inter alia facilitating spontaneous germinal center (GC) formation. Whereas both myeloid and B cell APCs express B7 ligands (CD80 and CD86), the prevailing model holds that dendritic cell costimulation is sufficient for CD28-dependent T cell activation. In this study, we report that B cell-intrinsic CD80/CD86 deletion unexpectedly abrogates GCs in murine lupus. Interestingly, absent GCs differentially impacted serum autoantibodies. In keeping with distinct extrafollicular and GC activation pathways driving lupus autoantibodies, lack of GCs correlated with loss of RNA-associated autoantibodies but preserved anti-dsDNA and connective tissue autoantibody titers. Strikingly, even heterozygous B cell CD80/CD86 deletion was sufficient to prevent autoimmune GCs and RNA-associated autoantibodies. Together, these findings identify a key mechanism whereby B cells promote lupus pathogenesis by providing a threshold of costimulatory signals required for autoreactive T cell activation.
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Linfócitos B/imunologia , Centro Germinativo/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Nefrite Lúpica/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Animais , Autoanticorpos/metabolismo , Autoimunidade , Antígeno B7-1/genética , Antígeno B7-1/metabolismo , Antígeno B7-2/genética , Antígeno B7-2/metabolismo , Células Cultivadas , Modelos Animais de Doenças , Humanos , Ativação Linfocitária , Camundongos , Camundongos Knockout , Receptor Cross-TalkRESUMO
B lymphocytes acquire self-reactivity as an unavoidable byproduct of antibody gene diversification in the bone marrow and in germinal centers (GCs). Autoreactive B cells emerging from the bone marrow are silenced in a series of well-defined checkpoints, but less is known about how self-reactivity that develops by somatic mutation in GCs is controlled. Here, we report the existence of an apoptosis-dependent tolerance checkpoint in post-GC B cells. Whereas defective GC B cell apoptosis has no measurable effect on autoantibody development, disruption of post-GC apoptosis results in accumulation of autoreactive memory B cells and plasma cells, antinuclear antibody production, and autoimmunity. The data presented shed light on mechanisms that regulate immune tolerance and the development of autoantibodies.
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Apoptose/genética , Autoimunidade/genética , Genes de Imunoglobulinas/genética , Tolerância Imunológica/genética , Animais , Anticorpos Antinucleares/imunologia , Apoptose/imunologia , Autoanticorpos/imunologia , Autoimunidade/imunologia , Linfócitos B/imunologia , Genes de Imunoglobulinas/imunologia , Centro Germinativo/imunologia , Humanos , Memória Imunológica/genética , Memória Imunológica/imunologia , Camundongos , Plasmócitos/imunologiaRESUMO
BACKGROUND & AIMS: Severe alcoholic hepatitis (AH) is a highly lethal condition and it is still a challenge to predict the outcome. We previously identified and validated a composite score of hepatic 123-gene prognostic signature and the model for end-stage liver disease (MELD) score: gene signature-MELD. However, the need for liver biopsy limits its clinical application. Therefore, we aimed to identify a plasma protein-based surrogate of the gene signature and independently validate its prognostic capability. METHODS: All patients were diagnosed with severe AH at Cliniques universitaires de Bruxelles Hôpital Erasme (Brussels, Belgium), and the plasma samples were collected at admission before any treatment. The primary outcome was death or liver transplantation within 90 days. Using our computational pipeline, named translation of tissue expression to secretome (TexSEC), a hepatic-transcriptome-based prognostic signature was converted to a plasma-based secretome signature, which was optimized in 50 patients by comparing their hepatic molecular dysregulation status and combining it with the MELD score. The composite score was validated independently in 57 patients. RESULTS: The TexSEC and optimization process identified a 6-plasma-protein panel as a surrogate for the 123-gene signature. A composite score with the MELD score, the plasma-signature (ps)-MELD score, was created by using the coefficients of the gene signature-MELD equation. In the validation cohort, the high-risk ps-MELD (n = 23; 40%) was associated significantly with death or liver transplantation within 90 days (adjusted hazard ratio, 4.57; 95% CI, 2.15-9.30; P < .001). The ps-MELD score showed a stable, high prognostic association (time-dependent area under receiver operating characteristics curve, >0.80) and was well calibrated over time; it consistently outperformed existing clinical scores as indicated by various model performance indices. CONCLUSIONS: The high-risk ps-MELD score was associated with short-term survival in patients with severe AH.
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Doença Hepática Terminal , Hepatite Alcoólica , Hepatite Alcoólica/tratamento farmacológico , Humanos , Testes de Função Hepática , Prognóstico , Curva ROC , Estudos Retrospectivos , Índice de Gravidade de DoençaRESUMO
Cirrhosis is the terminal stage of progressive liver fibrosis, affecting 1%-2% of the global population and accounting for 1.3 million deaths annually.1,2 Median survival for persons with compensated cirrhosis is approximately 12 years, compared with only 2 years for those with hepatic decompensation. Accurate prediction of hepatic decompensation is an unmet need to enable identification of patients with cirrhosis who could benefit from close monitoring and timely medical interventions. Besides, risk stratification of patients with cirrhosis could help inform patient selection for trials evaluating therapies to prevent hepatic decompensation. Although various clinical scores, such as the albumin-bilirubin (ALBI) and fibrosis-4 (FIB-4) indices (ALBI-FIB4 score) have been proposed to predict long-term risk of hepatic decompensation,3 external validation has often shown suboptimal prognostic capability and revealed room for improvement.4.