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Sequencing the tyrosine phosphoproteome using MS-based proteomics is challenging due to the low abundance of tyrosine phosphorylation in cells, a challenge compounded in scarce samples like primary cells or clinical samples. The broad-spectrum optimisation of selective triggering (BOOST) method was recently developed to increase phosphotyrosine sequencing in low protein input samples by leveraging tandem mass tags (TMT), phosphotyrosine enrichment, and a phosphotyrosine-loaded carrier channel. Here, we demonstrate the viability of BOOST in T cell receptor (TCR)-stimulated primary murine T cells by benchmarking the accuracy and precision of the BOOST method and discerning significant alterations in the phosphoproteome associated with receptor stimulation. Using 1 mg of protein input (about 20 million cells) and BOOST, we identify and precisely quantify more than 2000 unique pY sites compared to about 300 unique pY sites in non-BOOST control samples. We show that although replicate variation increases when using the BOOST method, BOOST does not jeopardise quantitative precision or the ability to determine statistical significance for peptides measured in triplicate. Many pY previously uncharacterised sites on important T cell signalling proteins are quantified using BOOST, and we identify new TCR responsive pY sites observable only with BOOST. Finally, we determine that the phase-spectrum deconvolution method on Orbitrap instruments can impair pY quantitation in BOOST experiments.
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The highly conserved MicroRNA-9 (miR-9) family consists of three members. We discovered that miR-9-1 deletion reduced mature miR-9 expression, causing 43% of the mice to display smaller size and postweaning lethality. MiR-9-1-deficient mice with growth defects experienced severe lymphopenia, but other blood cells were unaffected. The lymphopenia wasn't due to defects in hematopoietic progenitors, as mutant bone marrow (BM) cells underwent normal lymphopoiesis after transplantation into wild-type recipients. Additionally, miR-9-1-deficient mice exhibited impaired osteoblastic bone formation, as mutant mesenchymal stem cells (MSCs) failed to differentiate into osteoblastic cells (OBs). RNA sequencing revealed reduced expression of master transcription factors for osteoblastic differentiation, Runt-related transcription factor 2 (Runx2) and Osterix (Osx), and genes related to collagen formation, extracellular matrix organization, and cell adhesion, in miR-9-1-deficient MSCs. Follistatin (Fst), an antagonist of bone morphogenetic proteins (BMPs), was found to be a direct target of miR-9-1. Its deficiency led to the up-regulation of Fst, inhibiting BMP signaling in MSCs, and reducing IL-7 and IGF-1. Thus, miR-9-1 controls osteoblastic regulation of lymphopoiesis by targeting the Fst/BMP/Smad signaling axis.
Assuntos
Linfopenia , MicroRNAs , Animais , Camundongos , Linfopoese/genética , Proteínas Morfogenéticas Ósseas/metabolismo , Diferenciação Celular , MicroRNAs/genética , MicroRNAs/metabolismo , Osteogênese/genética , Osteoblastos/metabolismoRESUMO
Background: Patients with COVID-19 have a higher risk of thrombosis and thromboembolism, but the underlying mechanism(s) remain to be fully elucidated. In patients with COVID-19, high lipoprotein(a) (Lp(a)) is positively associated with the risk of ischemic heart disease. Lp(a), composed of an apoB-containing particle and apolipoprotein(a) (apo(a)), inhibits the key fibrinolytic enzyme, tissue-type plasminogen activator (tPA). However, whether the higher Lp(a) associates with lower tPA activity, the longitudinal changes of these parameters in hospitalized patients with COVID-19, and their correlation with clinical outcomes are unknown. Objectives: To assess if Lp(a) associates with lower tPA activity in COVID-19 patients, and how in COVID-19 populations Lp(a) and tPA change post infection. Methods: Endogenous tPA enzymatic activity, tPA or Lp(a) concentration were measured in plasma from hospitalized patients with and without COVID-19. The association between plasma tPA and adverse clinical outcomes was assessed. Results: In hospitalized patients with COVID-19, we found lower tPA enzymatic activity and higher plasma Lp(a) than that in non-COVID-19 controls. During hospitalization, Lp(a) increased and tPA activity decreased, which associates with mortality. Among those who survived, Lp(a) decreased and tPA enzymatic activity increased during recovery. In patients with COVID-19, tPA activity is inversely correlated with tPA concentrations, thus, in another larger COVID-19 cohort, we utilized plasma tPA concentration as a surrogate to inversely reflect tPA activity. The tPA concentration was positively associated with death, disease severity, plasma inflammatory, and prothrombotic markers, and with length of hospitalization among those who were discharged. Conclusion: High Lp(a) concentration provides a possible explanation for low endogenous tPA enzymatic activity, and poor clinical outcomes in patients with COVID-19.
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The caspase recruitment domain family member (CARD)11-Bcl10-Malt1 signalosome controls TGF-ß-activated kinase 1 (TAK1) activation and regulates BCR-induced NF-κB activation. In this study, we discovered that CARD19 interacted with TAK1 and inhibited TAB2-mediated TAK1 ubiquitination and activation. Although CARD19 deficiency in mice did not affect B cell development, it enhanced clonal deletion, receptor editing, and anergy of self-reactive B cells, and it reduced autoantibody production. Mechanistically, CARD19 deficiency increased BCR/TAK1-mediated NF-κB activation, leading to increased expression of transcription factors Egr2/3, as well as the E3 ubiquitin ligases c-Cbl/Cbl-b, which are known inducers of B cell tolerance in self-reactive B cells. RNA sequencing analysis revealed that although CARD19 deficiency did not affect the overall Ag-induced gene expression in naive B cells, it suppressed BCR signaling and increased hyporesponsiveness of self-reactive B cells. As a result, CARD19 deficiency prevented Bm12-induced experimental systemic lupus erythematosus. In summary, CARD19 negatively regulates BCR/TAK1-induced NF-κB activation and its deficiency increases Egr2/3 and c-Cbl/Cbl-b expression in self-reactive B cells, thereby enhancing B cell tolerance.
Assuntos
NF-kappa B , Transdução de Sinais , Animais , Camundongos , NF-kappa B/metabolismo , Transdução de Sinais/fisiologia , MAP Quinase Quinase Quinases/metabolismo , UbiquitinaçãoRESUMO
Heparin-induced thrombocytopenia (HIT) is a serious adverse drug reaction characterized by antibodies that recognize platelet factor 4/heparin complexes (PF4/H) and activate platelets to create a prothrombotic state. Although a high percentage of heparin-treated patients produce antibodies to PF4/H, only a subset also makes antibodies that are platelet activating (PA). A close correlation between PA antibodies and the likelihood of experiencing HIT has been demonstrated in clinical studies, but how PA (presumptively pathogenic) and nonactivating (NA) (presumptively benign) antibodies differ from each other at the molecular level is unknown. To address this issue, we cloned 7 PA and 47 NA PF4/H-binding antibodies from 6 patients with HIT and characterized their structural and functional properties. Findings showed that PA clones differed significantly from NA clones in possessing 1 of 2 heavy chain complementarity-determining region 3 (HCDR3) motifs, RX1-2R/KX1-2R/H (RKH) and YYYYY (Y5), in an unusually long complementarity-determining region 3 (≥20 residues). Mutagenic studies showed that modification of either motif in PA clones reduced or abolished their PA activity and that appropriate amino acid substitutions in HCDR3 of NA clones can cause them to become PA. Repertoire sequencing showed that the frequency of peripheral blood IgG+ B cells possessing RKH or Y5 was significantly higher in patients with HIT than in patients without HIT given heparin, indicating expansion of B cells possessing RKH or Y5 in HIT. These findings imply that antibodies possessing RKH or Y5 are relevant to HIT pathogenesis and suggest new approaches to diagnosis and treatment of this condition.
Assuntos
Regiões Determinantes de Complementaridade , Trombocitopenia , Humanos , Regiões Determinantes de Complementaridade/genética , Trombocitopenia/induzido quimicamente , Trombocitopenia/genética , Heparina , Anticorpos/efeitos adversos , Plaquetas/metabolismo , Fator Plaquetário 4Assuntos
Peptídeos e Proteínas de Sinalização Intracelular , Leucemia , Proteínas Monoméricas de Ligação ao GTP , Fosfoproteínas , Células Precursoras de Linfócitos T , Animais , GTP Fosfo-Hidrolases , Haploinsuficiência/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Leucemia/genética , Proteínas de Membrana , Camundongos , Proteínas Monoméricas de Ligação ao GTP/genética , Mutação , Proteínas Nucleares , Fosfoproteínas/genéticaRESUMO
Severe COVID-19 is associated with unprecedented thromboembolic complications. We found that hospitalized COVID-19 patients develop immunoglobulin Gs (IgGs) that recognize a complex consisting of platelet factor 4 and heparin similar to those developed in heparin-induced thrombocytopenia and thrombosis (HIT), however, independent of heparin exposure. These antibodies activate platelets in the presence of TLR9 stimuli, stimuli that are prominent in COVID-19. Strikingly, 4 out of 42 antibodies cloned from IgG1+ RBD-binding B cells could activate platelets. These antibodies possessed, in the heavy-chain complementarity-determining region 3, an RKH or Y5 motif that we recently described among platelet-activating antibodies cloned from HIT patients. RKH and Y5 motifs were prevalent among published RBD-specific antibodies, and 3 out of 6 such antibodies tested could activate platelets. Features of platelet activation by these antibodies resemble those by pathogenic HIT antibodies. B cells with an RKH or Y5 motif were robustly expanded in COVID-19 patients. Our study demonstrates that SARS-CoV-2 infection drives the development of a subset of RBD-specific antibodies that can activate platelets and have activation properties and structural features similar to those of the pathogenic HIT antibodies.
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Yin Yang 1 (YY1) is a ubiquitous transcription factor and mammalian Polycomb Group protein (PcG) with important functions for regulating lymphocyte development and stem cell self-renewal. YY1 mediates stable PcG-dependent transcriptional repression via recruitment of PcG proteins that result in histone modifications. Many questions remain unanswered regarding how cell- and tissue-specificity is achieved by PcG proteins. Here, we demonstrate that a conditional knockout of Yy1 in the hematopoietic system results in an early T cell developmental blockage at the double negative (DN) 1 stage with reduced Notch1 signaling. There is a lineage-specific requirement for YY1 PcG function. YY1 PcG domain is required for T and B cell development but not necessary for myeloid cells. YY1 functions in early T cell development are multicomponent and involve both PcG-dependent and -independent regulations. Although YY1 promotes early T cell survival through its PcG function, its function to promote the DN1-to-DN2 transition and Notch1 expression and signaling is independent of its PcG function. Our results reveal how a ubiquitously expressed PcG protein mediates lineage-specific and context-specific functions to control early T cell development.
Assuntos
Diferenciação Celular/fisiologia , Proteínas do Grupo Polycomb/genética , Proteínas do Grupo Polycomb/metabolismo , Linfócitos T/metabolismo , Fator de Transcrição YY1/genética , Fator de Transcrição YY1/metabolismo , Animais , Sobrevivência Celular , Regulação da Expressão Gênica no Desenvolvimento , Camundongos , Camundongos Knockout , Receptor Notch1 , TranscriptomaRESUMO
Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is an aggressive subtype of T-cell ALL. Although genetic mutations hyperactivating cytokine receptor/Ras signaling are prevalent in ETP-ALL, it remains unknown how activated Ras signaling contributes to ETP-ALL. Here, we find that in addition to the frequent oncogenic RAS mutations, wild-type (WT) KRAS transcript level was significantly downregulated in human ETP-ALL cells. Similarly, loss of WT Kras in NrasQ61R/+ mice promoted hyperactivation of extracellular signal-regulated kinase (ERK) signaling, thymocyte hyperproliferation, and expansion of the ETP compartment. Kras-/-; NrasQ61R/+ mice developed early onset of T-cell malignancy that recapitulates many biological and molecular features of human ETP-ALL. Mechanistically, RNA-sequencing analysis and quantitative proteomics study identified that Rasgrp1, a Ras guanine nucleotide exchange factor, was greatly downregulated in mouse and human ETP-ALL. Unexpectedly, hyperactivated Nras/ERK signaling suppressed Rasgrp1 expression and reduced Rasgrp1 level led to increased ERK signaling, thereby establishing a positive feedback loop to augment Nras/ERK signaling and promote cell proliferation. Corroborating our cell line data, Rasgrp1 haploinsufficiency induced Rasgrp1 downregulation and increased phosphorylated ERK level and ETP expansion in NrasQ61R/+ mice. Our study identifies Rasgrp1 as a negative regulator of Ras/ERK signaling in oncogenic Nras-driven ETP-like leukemia.
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Regulação para Baixo , Regulação Leucêmica da Expressão Gênica , Fatores de Troca do Nucleotídeo Guanina , Proteínas Monoméricas de Ligação ao GTP , Mutação de Sentido Incorreto , Leucemia-Linfoma Linfoblástico de Células T Precursoras , Proteínas Proto-Oncogênicas p21(ras)/deficiência , Substituição de Aminoácidos , Animais , Proliferação de Células/genética , Fatores de Troca do Nucleotídeo Guanina/genética , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Humanos , Sistema de Sinalização das MAP Quinases/genética , Camundongos , Camundongos Knockout , Proteínas Monoméricas de Ligação ao GTP/genética , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Proteínas Proto-Oncogênicas p21(ras)/metabolismoRESUMO
Acute graft-versus-host disease (aGVHD) is one major serious complication that is induced by alloreactive donor T cells recognizing host Ags and limits the success of allogeneic hematopoietic stem cell transplantation. In the current studies, we identified a critical role of Kras in regulating alloreactive T cell function during aGVHD. Kras deletion in donor T cells dramatically reduced aGVHD mortality and severity in an MHC-mismatched allogeneic hematopoietic stem cell transplantation mouse model but largely maintained the antitumor capacity. Kras-deficient CD4 and CD8 T cells exhibited impaired TCR-induced activation of the ERK pathway. Kras deficiency altered TCR-induced gene expression profiles, including the reduced expression of various inflammatory cytokines and chemokines. Moreover, Kras deficiency inhibited IL-6-mediated Th17 cell differentiation and impaired IL-6-induced ERK activation and gene expression in CD4 T cells. These findings support Kras as a novel and effective therapeutic target for aGVHD.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Doença Enxerto-Hospedeiro/imunologia , Efeito Enxerto vs Leucemia/imunologia , Transplante de Células-Tronco Hematopoéticas , Proteínas Proto-Oncogênicas p21(ras)/deficiência , Células Th17/imunologia , Aloenxertos , Animais , Linhagem Celular Tumoral , Doença Enxerto-Hospedeiro/genética , Efeito Enxerto vs Leucemia/genética , Interleucina-6/genética , Interleucina-6/imunologia , Sistema de Sinalização das MAP Quinases/genética , Sistema de Sinalização das MAP Quinases/imunologia , Camundongos , Camundongos Transgênicos , Proteínas Proto-Oncogênicas p21(ras)/imunologiaRESUMO
Heparin-induced thrombocytopenia is a relatively common drug-induced immune disorder that can have life-threatening consequences for affected patients. Immune complexes consisting of heparin, platelet factor 4 (PF4), and PF4/heparin-reactive Abs are central to the pathogenesis of heparin-induced thrombocytopenia. Regulatory T (Treg) cells are a subpopulation of CD4 T cells that play a key role in regulating immune responses, but their role in controlling PF4/heparin-specific Ab production is unknown. In the studies described in this article, we found that Foxp3-deficient mice lacking functional Treg cells spontaneously produced PF4/heparin-specific Abs. Following transplantation with bone marrow cells from Foxp3-deficient but not wild-type mice, Rag1-deficient recipients also produced PF4/heparin-specific Abs spontaneously. Adoptively transferred Treg cells prevented spontaneous production of PF4/heparin-specific Abs in Foxp3-deficient mice and inhibited PF4/heparin complex-induced production of PF4/heparin-specific IgGs in wild-type mice. Treg cells suppress immune responses mainly through releasing anti-inflammatory cytokines, such as IL-10. IL-10-deficient mice spontaneously produced PF4/heparin-specific Abs. Moreover, bone marrow chimeric mice with CD4 T cell-specific deletion of IL-10 increased PF4/heparin-specific IgG production upon PF4/heparin complex challenge. Short-term IL-10 administration suppresses PF4/heparin-specific IgG production in wild-type mice. Taken together, these findings demonstrate that Treg cells play an important role in suppressing PF4/heparin-specific Ab production.
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Formação de Anticorpos , Heparina/imunologia , Imunoglobulina G/imunologia , Fator Plaquetário 4/imunologia , Linfócitos T Reguladores/imunologia , Animais , Fatores de Transcrição Forkhead/deficiência , Fatores de Transcrição Forkhead/imunologia , Heparina/genética , Imunoglobulina G/genética , Interleucina-10/deficiência , Interleucina-10/imunologia , Camundongos , Camundongos Knockout , Fator Plaquetário 4/genética , Linfócitos T Reguladores/citologiaRESUMO
Many autoimmune diseases are characterized by the production of autoantibodies. The current view is that CD4+ T follicular helper (Tfh) cells are the main subset regulating autoreactive B cells. Here we report a CXCR5+PD1+ Tfh subset of CD8+ T cells whose development and function are negatively modulated by Stat5. These CD8+ Tfh cells regulate the germinal center B cell response and control autoantibody production, as deficiency of Stat5 in CD8 T cells leads to an increase of CD8+ Tfh cells, resulting in the breakdown of B cell tolerance and concomitant autoantibody production. CD8+ Tfh cells share similar gene signatures with CD4+ Tfh, and require CD40L/CD40 and TCR/MHCI interactions to deliver help to B cells. Our study thus highlights the diversity of follicular T cell subsets that contribute to the breakdown of B-cell tolerance.
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Linfócitos B/imunologia , Linfócitos T CD8-Positivos/imunologia , Tolerância Imunológica/imunologia , Receptor de Morte Celular Programada 1/imunologia , Receptores CXCR5/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Autoanticorpos/imunologia , Autoanticorpos/metabolismo , Doenças Autoimunes/genética , Doenças Autoimunes/imunologia , Doenças Autoimunes/metabolismo , Linfócitos B/metabolismo , Antígenos CD40/genética , Antígenos CD40/imunologia , Antígenos CD40/metabolismo , Ligante de CD40/genética , Ligante de CD40/imunologia , Ligante de CD40/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Perfilação da Expressão Gênica/métodos , Humanos , Tolerância Imunológica/genética , Receptor de Morte Celular Programada 1/genética , Receptor de Morte Celular Programada 1/metabolismo , Receptores CXCR5/genética , Receptores CXCR5/metabolismo , Fator de Transcrição STAT5/genética , Fator de Transcrição STAT5/imunologia , Fator de Transcrição STAT5/metabolismo , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Linfócitos T Auxiliares-Indutores/metabolismoRESUMO
Inflammatory Bowel Disease (IBD) is a multi-factorial chronic inflammation of the gastrointestinal tract prognostically linked to CD8+ T-cells, but little is known about their mechanism of activation during initiation of colitis. Here, Grb2-associated binding 2/3 adaptor protein double knockout mice (Gab2/3-/-) were generated. Gab2/3-/- mice, but not single knockout mice, developed spontaneous colitis. To analyze the cellular mechanism, reciprocal bone marrow (BM) transplantation demonstrated a Gab2/3-/- hematopoietic disease-initiating process. Adoptive transfer showed individual roles for macrophages and T-cells in promoting colitis development in vivo. In spontaneous disease, intestinal intraepithelial CD8+ but much fewer CD4+, T-cells from Gab2/3-/- mice with rectal prolapse were more proliferative. To analyze the molecular mechanism, reduced PI3-kinase/Akt/mTORC1 was observed in macrophages and T-cells, with interleukin (IL)-2 stimulated T-cells showing increased pSTAT5. These results illustrate the importance of Gab2/3 collectively in signaling responses required to control macrophage and CD8+ T-cell activation and suppress chronic colitis.
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Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Linfócitos T CD8-Positivos/imunologia , Colite/imunologia , Doenças Inflamatórias Intestinais/imunologia , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Proteínas Adaptadoras de Transdução de Sinal/genética , Transferência Adotiva , Animais , Linfócitos T CD8-Positivos/transplante , Colite/patologia , Modelos Animais de Doenças , Linfócitos Intraepiteliais/imunologia , Lipocalina-2/análise , Ativação Linfocitária , Ativação de Macrófagos , Macrófagos/transplante , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Fosfatidilinositol 3-Quinases/fisiologia , Proteínas Proto-Oncogênicas c-akt/fisiologia , Quimera por Radiação , Prolapso Retal/etiologia , Prolapso Retal/imunologia , Prolapso Retal/patologia , Transdução de Sinais , Serina-Treonina Quinases TOR/fisiologiaRESUMO
The precise molecular mechanism underlying the regulation of early B cell lymphopoiesis is unclear. The PLCγ signaling pathway is critical for antigen receptor-mediated lymphocyte activation, but its function in cytokine signaling is unknown. Here we show that PLCγ1/PLCγ2 double deficiency in mice blocks early B cell development at the pre-pro-B cell stage and renders B cell progenitors unresponsive to IL-7. PLCγ pathway inhibition blocks IL-7-induced activation of mTOR, but not Stat5. The PLCγ pathway activates mTOR through the DAG/PKC signaling branch, independent of the conventional Akt/TSC/Rheb signaling axis. Inhibition of PLCγ/PKC-induced mTOR activation impairs IL-7-mediated B cell development. PLCγ1/PLCγ2 double-deficient B cell progenitors have reduced expression of genes related to B cell lineage, IL-7 signaling, and cell cycle. Thus, IL-7 receptor controls early B lymphopoiesis through activation of mTOR via PLCγ/DAG/PKC signaling, not via Akt/Rheb signaling.
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Interleucina-7/imunologia , Linfopoese/imunologia , Fosfolipase C gama/deficiência , Fosfolipase C gama/imunologia , Células Precursoras de Linfócitos B/citologia , Serina-Treonina Quinases TOR/metabolismo , Animais , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosfolipase C gama/genética , Células Precursoras de Linfócitos B/imunologia , Fator de Transcrição STAT5/metabolismo , Transdução de Sinais/imunologiaRESUMO
BACKGROUND: Heparin-induced thrombocytopenia (HIT) complicated by severe thrombocytopenia and thrombosis can pose significant treatment challenges. Use of alternative anticoagulants in this setting may increase bleeding risks, especially in patients who have a protracted disease course. Additional therapies are lacking in this severely affected patient population. METHODS: We describe three patients with HIT who had severe thromboembolism and prolonged thrombocytopenia refractory to standard treatment but who achieved an immediate and sustained response to IVIg therapy. The mechanism of action of IVIg was evaluated in these patients and in five additional patients with severe HIT. The impact of a common polymorphism (H/R 131) in the platelet IgG receptor FcγRIIa on IVIg-mediated inhibition of platelet activation was also examined. RESULTS: At levels attained in vivo, IVIg inhibits HIT antibody-mediated platelet activation. The constant domain of IgG (Fc) but not the antigen-binding portion (Fab) is required for this effect. Consistent with this finding, IVIg had no effect on HIT antibody binding in a solid-phase HIT immunoassay (platelet factor 4 enzyme-linked immunoassay). The H/R131 polymorphism in FcγRIIa influences the susceptibility of platelets to IVIg treatment, with the HH131 genotype being most susceptible to IVIg-mediated inhibition of antibody-induced activation. However, at high doses of IVIg, activation of platelets of all FcγRIIa genotypes was significantly inhibited. All three patients did well on long-term anticoagulation therapy with direct oral anticoagulants. CONCLUSIONS: These studies suggest that IVIg treatment should be considered in patients with HIT who have severe disease that is refractory to standard therapies.