RESUMO
Multiple myeloma (MM) is an incurable hematological cancer, in which immune checkpoint inhibition (ICI) with monoclonal antibodies (mAbs) has failed due to uncontrollable immune responses in combination therapies and lack of efficacy in monotherapies. Although NK cell-specific checkpoint targets such as NKG2A and KIRs are currently being evaluated in clinical trials, the clinical impact of NK cells on the PD1 cascade is less well understood compared to T cells. Furthermore, while NK cells have effector activity within the TME, under continuous ligand exposure, NK cell dysfunctionality may occur due to interaction of PD1 and its ligand PD-L1. Due to above-mentioned factors, we designed novel NK cell specific PD1-based chimeric switch receptors (PD1-CSR) by employing signaling domains of DAP10, DAP12 and CD3ζ to revert NK cell inhibition and retarget ICI. PD1-CSR modified NK cells showed increased degranulation, cytokine secretion and cytotoxicity upon recognition of PD-L1+ target cells. Additionally, PD1-CSR+ NK cells infiltrated and killed tumor spheroids. While primary NK cells (pNK), expressing native PD1, showed decreased degranulation and cytokine production against PD-L1+ target cells by twofold, PD1-CSR+ pNK cells demonstrated increased activity upon PD-L1+ target cell recognition and enhanced antibody-dependent cellular cytotoxicity. PD1-CSR+ pNK cells from patients with MM increased degranulation and cytokine expression against autologous CD138+PD-L1+ malignant plasma cells. Taken together, the present results demonstrate that PD1-CSR+ NK cells enhance and sustain potent anti-tumor activity in a PD-L1+ microenvironment and thus represent a promising strategy to advance adoptive NK cell-based immunotherapies toward PD-L1+ cancers.
Assuntos
Antígeno B7-H1 , Mieloma Múltiplo , Humanos , Antígeno B7-H1/metabolismo , Ligantes , Células Matadoras Naturais , Citocinas/metabolismo , Receptores de Células Matadoras Naturais/metabolismo , Imunoterapia/métodos , Microambiente TumoralRESUMO
Tyrosine kinase inhibitors (TKIs) have dramatically improved the survival in chronic myeloid leukemia (CML), but residual disease typically persists even after prolonged treatment. Several lines of evidence suggest that TKIs administered to CML patients upregulate interferon γ (IFNγ) production, which may counteract the anti-tumorigenic effects of the therapy. We now show that activated T cell-conditioned medium (TCM) enhanced proliferation and counteracted imatinib-induced apoptosis of CML cells, and addition of a neutralizing anti-IFNγ antibody at least partially inhibited the anti-apoptotic effect. Likewise, recombinant IFNγ also reduced imatinib-induced apoptosis of CML cells. This anti-apoptotic effect of IFNγ was independent of alternative IFNγ signaling pathways, but could be notably diminished by STAT1-knockdown. Furthermore, IFNγ upregulated the expression of several anti-apoptotic proteins, including MCL1, PARP9, and PARP14, both in untreated and imatinib-treated primary human CD34+ CML stem/progenitor cells. Our results suggest that activated T cells in imatinib-treated CML patients can directly rescue CML cells from imatinib-induced apoptosis at least partially through the secretion of IFNγ, which exerts a rapid, STAT1-dependent anti-apoptotic effect potentially through the simultaneous upregulation of several key hematopoietic survival factors. These mechanisms may have a major clinical impact, when targeting residual leukemic stem/progenitor cells in CML.
Assuntos
Interferon gama , Leucemia Mielogênica Crônica BCR-ABL Positiva , Antígenos CD34/metabolismo , Antígenos CD34/farmacologia , Apoptose , Linhagem Celular Tumoral , Humanos , Mesilato de Imatinib/farmacologia , Mesilato de Imatinib/uso terapêutico , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Células-Tronco/metabolismo , Regulação para CimaRESUMO
Tyrosine kinase inhibitor (TKI) treatment has dramatically improved the survival of chronic myeloid leukemia (CML) patients, but measurable residual disease typically persists. To more effectively eradicate leukemia cells, simultaneous targeting of BCR-ABL1 and additional CML-related survival proteins has been proposed. Notably, several highly specific myeloid cell leukemia 1 (MCL1) inhibitors have recently entered clinical trials for various hematologic malignancies, although not for CML, reflecting the insensitivity of CML cell lines to single MCL1 inhibition. Here, we show that combining TKI (imatinib, nilotinib, dasatinib, or asciminib) treatment with the small-molecule MCL1 inhibitor S63845 exerted strong synergistic antiviability and proapoptotic effects on CML lines and CD34+ stem/progenitor cells isolated from untreated CML patients in chronic phase. Using wild-type BCR-ABL1-harboring CML lines and their T315I-mutated sublines (generated by CRISPR/Cas9-mediated homologous recombination), we prove that the synergistic proapoptotic effect of the drug combination depended on TKI-mediated BCR-ABL1 inhibition, but not on TKI-related off-target mechanisms. Moreover, we demonstrate that colony formation of CML but not normal hematopoietic stem/progenitor cells became markedly reduced upon combination treatment compared to imatinib monotherapy. Our results suggest that dual targeting of MCL1 and BCR-ABL1 activity may efficiently eradicate residual CML cells without affecting normal hematopoietic stem/progenitors.
Assuntos
Antineoplásicos/farmacologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/farmacologia , Tiofenos/farmacologia , Antígenos CD34/metabolismo , Protocolos de Quimioterapia Combinada Antineoplásica , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Caspase 7/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Células Clonais , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Sinergismo Farmacológico , Células-Tronco Hematopoéticas/efeitos dos fármacos , Células-Tronco Hematopoéticas/metabolismo , Humanos , Mesilato de Imatinib/administração & dosagem , Mesilato de Imatinib/farmacologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/antagonistas & inibidores , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Proteínas de Neoplasias/metabolismo , Proteínas de Ligação a Fosfato/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Piroptose/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/farmacologia , Proteína bcl-X/metabolismoRESUMO
X-linked neutropenia (XLN) is caused by gain-of-function mutations in the actin regulator Wiskott-Aldrich Syndrome protein (WASp). XLN patients have reduced numbers of cytotoxic cells in peripheral blood; however, their capacity to kill tumor cells remains to be determined. Here, we examined NK and T cells from 2 patients with XLN harboring the activating WASpL270P mutation. XLN patient NK and T cells had increased granzyme B content and elevated degranulation and IFN-γ production when compared with healthy control cells. Murine WASpL272P NK and T cells formed stable synapses with YAC-1 tumor cells and anti-CD3/CD28-coated beads, respectively. WASpL272P mouse T cells had normal degranulation and cytokine response whereas WASpL272P NK cells showed an enhanced response. Imaging experiments revealed that while WASpL272P CD8+ T cells had increased accumulation of actin upon TCR activation, WASpL272P NK cells had normal actin accumulation at lytic synapses triggered through NKp46 signaling but had impaired response to lymphocyte function associated antigen-1 engagement. When compared with WT mice, WASpL272P mice showed reduced growth of B16 melanoma and increased capacity to reject MHC class I-deficient cells. Together, our data suggest that cytotoxic cells with constitutively active WASp have an increased capacity to respond to and kill tumor cells.
Assuntos
Degranulação Celular , Granzimas/metabolismo , Proteína da Síndrome de Wiskott-Aldrich/metabolismo , Síndrome de Wiskott-Aldrich/imunologia , Animais , Estudos de Casos e Controles , Camundongos , Neoplasias/imunologia , Neoplasias/patologia , Linfócitos T Citotóxicos/imunologia , Síndrome de Wiskott-Aldrich/genética , Síndrome de Wiskott-Aldrich/patologiaRESUMO
The Wiskott-Aldrich syndrome protein (WASp) is a key regulator of the actin cytoskeleton in hematopoietic cells and mutated in two severe immunodeficiency diseases with high incidence of cancer. Wiskott-Aldrich syndrome (WAS) is caused by loss-of-function mutations in WASp and most frequently associated with lymphoreticular tumors of poor prognosis. X-linked neuropenia (XLN) is caused by gain-of-function mutations in WASp and associated with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). To understand the role of WASp in tumorigenesis, we bred WASp+, WASp-, and WASp-XLN mice onto tumor susceptible p53+/- background and sub-lethally irradiated them to enhance tumor development. We followed the cohorts for 24 weeks and tumors were characterized by histology and flow cytometry to define the tumor incidence, onset, and cell origin. We found that p53+/-WASp+ mice developed malignancies, including solid tumors and T cell lymphomas with 71.4% of survival 24 weeks after irradiation. p53+/-WASp- mice showed lower survival rate and developed various early onset malignancies. Surprisingly, the p53+/-WASp-XLN mice developed malignancy mostly with late onset, which caused delayed mortality in this colony. This study provides evidence for that loss-of-function and gain-of-function mutations in WASp influence tumor incidence and onset.
RESUMO
Congenital neutropenia is characterized by low absolute neutrophil numbers in blood, leading to recurrent bacterial infections, and patients often require life-long granulocyte CSF (G-CSF) support. X-linked neutropenia (XLN) is caused by gain-of-function mutations in the actin regulator Wiskott-Aldrich syndrome protein (WASp). To understand the pathophysiology in XLN and the role of WASp in neutrophils, we here examined XLN patients and 2 XLN mouse models. XLN patients had reduced myelopoiesis and extremely low blood neutrophil number. However, their neutrophils had a hyperactive phenotype and were present in normal numbers in XLN patient saliva. Murine XLN neutrophils were hyperactivated, with increased actin dynamics and migration into tissues. We provide molecular evidence that the hyperactivity of XLN neutrophils is caused by WASp in a constitutively open conformation due to contingent phosphorylation of the critical tyrosine-293 and plasma membrane localization. This renders WASp activity less dependent on regulation by PI3K. Our data show that the amplitude of WASp activity inside a cell could be enhanced by cell-surface receptor signaling even in the context in which WASp is already in an active conformation. Moreover, these data categorize XLN as an atypical congenital neutropenia in which constitutive activation of WASp in tissue neutrophils compensates for reduced myelopoiesis.
Assuntos
Doenças Genéticas Ligadas ao Cromossomo X/genética , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Neutropenia/genética , Neutropenia/metabolismo , Neutrófilos/metabolismo , Proteína da Síndrome de Wiskott-Aldrich/genética , Proteína da Síndrome de Wiskott-Aldrich/metabolismo , Animais , Síndrome Congênita de Insuficiência da Medula Óssea , Feminino , Mutação com Ganho de Função , Técnicas de Introdução de Genes , Humanos , Masculino , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neutropenia/congênito , Neutrófilos/ultraestrutura , Fagocitose , Fosforilação , Conformação Proteica , Proteína da Síndrome de Wiskott-Aldrich/químicaRESUMO
Patients with mutations of the recombination-activating genes (RAG) present with diverse clinical phenotypes, including severe combined immune deficiency (SCID), autoimmunity, and inflammation. However, the incidence and extent of immune dysregulation in RAG-dependent immunodeficiency have not been studied in detail. Here, we have demonstrated that patients with hypomorphic RAG mutations, especially those with delayed-onset combined immune deficiency and granulomatous/autoimmune manifestations (CID-G/AI), produce a broad spectrum of autoantibodies. Neutralizing anti-IFN-α or anti-IFN-ω antibodies were present at detectable levels in patients with CID-G/AI who had a history of severe viral infections. As this autoantibody profile is not observed in a wide range of other primary immunodeficiencies, we hypothesized that recurrent or chronic viral infections may precipitate or aggravate immune dysregulation in RAG-deficient hosts. We repeatedly challenged Rag1S723C/S723C mice, which serve as a model of leaky SCID, with agonists of the virus-recognizing receptors TLR3/MDA5, TLR7/-8, and TLR9 and found that this treatment elicits autoantibody production. Altogether, our data demonstrate that immune dysregulation is an integral aspect of RAG-associated immunodeficiency and indicate that environmental triggers may modulate the phenotypic expression of autoimmune manifestations.
Assuntos
Autoanticorpos/imunologia , Autoantígenos/imunologia , Doenças Autoimunes/imunologia , Citocinas/imunologia , Proteínas de Ligação a DNA/deficiência , Doença Granulomatosa Crônica/imunologia , Proteínas de Homeodomínio/imunologia , Proteínas Nucleares/deficiência , Imunodeficiência Combinada Severa/imunologia , Adolescente , Adulto , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Especificidade de Anticorpos , Autoanticorpos/sangue , Doenças Autoimunes/genética , Criança , Pré-Escolar , RNA Helicases DEAD-box/imunologia , Proteínas de Ligação a DNA/genética , Modelos Animais de Doenças , Feminino , Doença Granulomatosa Crônica/genética , Doença Granulomatosa Crônica/terapia , Proteínas de Homeodomínio/genética , Humanos , Lactente , Helicase IFIH1 Induzida por Interferon , Masculino , Camundongos , Camundongos Endogâmicos , Proteínas Nucleares/genética , Imunodeficiência Combinada Severa/genética , Imunodeficiência Combinada Severa/terapia , Receptores Toll-Like/agonistas , Receptores Toll-Like/imunologia , Viroses/imunologia , Adulto JovemRESUMO
Humoral immunodeficiency caused by mutations in the Wiskott-Aldrich syndrome protein (WASp) is associated with failure to respond to common pathogens and high frequency of autoimmunity. Here we addressed the question how deficiency in WASp and the homologous protein N-WASp skews the immune response towards autoreactivity. Mice devoid of WASp or both WASp and N-WASp in B cells formed germinal center to increased load of apoptotic cells as a source of autoantigens. However, the germinal centers showed abolished polarity and B cells retained longer and proliferated less in the germinal centers. While WASp-deficient mice had high titers of autoreactive IgG, B cells devoid of both WASp and N-WASp produced mainly IgM autoantibodies with broad reactivity to autoantigens. Moreover, B cells lacking both WASp and N-WASp induced somatic hypermutation at reduced frequency. Despite this, IgG1-expressing B cells devoid of WASp and N-WASp acquired a specific high affinity mutation, implying an increased BCR signaling threshold for selection in germinal centers. Our data provides evidence for that N-WASp expression alone drives WASp-deficient B cells towards autoimmunity.
Assuntos
Autoanticorpos/imunologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Deleção de Genes , Centro Germinativo/imunologia , Centro Germinativo/metabolismo , Imunoglobulina M/imunologia , Proteína da Síndrome de Wiskott-Aldrich/genética , Animais , Anticorpos Antinucleares/sangue , Anticorpos Antinucleares/imunologia , Formação de Anticorpos , Antígenos CD19/genética , Apoptose/genética , Apoptose/imunologia , Autoanticorpos/sangue , Autoantígenos/imunologia , Linfócitos B/citologia , Transplante de Medula Óssea , Diferenciação Celular , Haptenos , Hemocianinas/imunologia , Imunoglobulina M/sangue , Ativação Linfocitária/genética , Ativação Linfocitária/imunologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Quimeras de TransplanteRESUMO
Mutations affecting the SLAM-associated protein (SAP) are responsible for the X-linked lympho-proliferative syndrome (XLP), a severe primary immunodeficiency syndrome with disease manifestations that include fatal mononucleosis, B cell lymphoma and dysgammaglobulinemia. It is well accepted that insufficient help by SAP-/- CD4+ T cells, in particular during the germinal center reaction, is a component of dysgammaglobulinemia in XLP patients and SAP-/- animals. It is however not well understood whether in XLP patients and SAP-/- mice B cell functions are affected, even though B cells themselves do not express SAP. Here we report that B cell intrinsic responses to haptenated protein antigens are impaired in SAP-/- mice and in Rag-/- mice into which B cells derived from SAP-/- mice together with wt CD4+ T cells had been transferred. This impaired B cells functions are in part depending on the genetic background of the SAP-/- mouse, which affects B cell homeostasis. Surprisingly, stimulation with an agonistic anti-CD40 causes strong in vivo and in vitro B cell responses in SAP-/- mice. Taken together, the data demonstrate that genetic factors play an important role in the SAP-related B cell functions. The finding that anti-CD40 can in part restore impaired B cell responses in SAP-/- mice, suggests potentially novel therapeutic interventions in subsets of XLP patients.
Assuntos
Linfócitos B/imunologia , Linfócitos T CD4-Positivos/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Transtornos Linfoproliferativos/genética , Transtornos Linfoproliferativos/imunologia , Animais , Linfócitos B/citologia , Linfócitos T CD4-Positivos/transplante , Antígenos CD40/imunologia , Antígenos CD40/metabolismo , Proteínas de Homeodomínio/genética , Leucossialina/metabolismo , Ativação Linfocitária/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína Associada à Molécula de Sinalização da Ativação LinfocitáriaRESUMO
The costimulatory receptor Slamf6 partially controls lupus-related autoimmunity in congenic Sle1b mice; for instance, the presence of the protein isoform Slamf6-H1 in Sle1b.Slamf6-H1 mice mitigates disease. Here, we report that young Sle1b mice, but not Sle1b.Slamf6-H1 or B6 mice, contain a memory T-helper cell subset identified by ]mt]2-fold increase in expression of 17 genes, chief among which is Spp1, encoding the cytokine osteopontin (OPN). These T follicular helper (TFH) cells, including OPN(+) TFH cells, expand concomitantly with severity of the disease. By contrast, Sle1b.Slamf6-H1 or Sle1b.SAP(-)/(-) mice do not develop autoantibodies and the number of T(FH) cells is 5 times lower than in age-matched Sle1b mice. By comparing Sle1b and Sle1b.OPN(-)/(-) mice, we find that the lack of OPN expression impedes early autoantibody production. Furthermore, on the adoptive transfer of Sle1b.OPN(-)/(-) CD4(+) T cells into bm12 recipients autoantibody production and germinal center formation is reduced compared to recipients of Sle1b.OPN(+/+) CD4(+) T cells. We propose a model in which OPN provides a survival signal for a precursor T(FH) cell subset, which is a key factor in autoimmunity.
Assuntos
Antígenos CD/imunologia , Autoimunidade/imunologia , Osteopontina/imunologia , Receptores de Superfície Celular/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Animais , Antígenos CD/genética , Antígenos CD/metabolismo , Antígenos de Diferenciação/genética , Antígenos de Diferenciação/imunologia , Antígenos de Diferenciação/metabolismo , Autoimunidade/genética , Western Blotting , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Proliferação de Células , Feminino , Citometria de Fluxo , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/metabolismo , Masculino , Camundongos , Camundongos Knockout , Osteopontina/genética , Osteopontina/metabolismo , Receptor de Morte Celular Programada 1 , Isoformas de Proteínas/genética , Isoformas de Proteínas/imunologia , Isoformas de Proteínas/metabolismo , Receptores CXCR5/genética , Receptores CXCR5/imunologia , Receptores CXCR5/metabolismo , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Família de Moléculas de Sinalização da Ativação Linfocitária , Membro 1 da Família de Moléculas de Sinalização da Ativação Linfocitária , Linfócitos T Auxiliares-Indutores/citologia , Linfócitos T Auxiliares-Indutores/metabolismo , Transcriptoma/imunologiaRESUMO
One of the manifestations of X-linked lymphoproliferative disease (XLP) is progressive agammaglobulinemia, caused by the absence of a functional signaling lymphocyte activation molecule (SLAM)-associated protein (SAP) in T, invariant natural killer T (NKT) cells and NK cells. Here we report that α-galactosylceramide (αGalCer) activated NKT cells positively regulate antibody responses to haptenated protein antigens at multiple checkpoints, including germinal center formation and affinity maturation. Whereas NKT cell-dependent B cell responses were absent in SAP(-/-).B6 mice that completely lack NKT cells, the small number of SAP-deficient NKT cells in SAP(-/-).BALB/c mice adjuvated antibody production, but not the germinal center reaction. To test the hypothesis that SAP-deficient NKT cells can facilitate humoral immunity, SAP was deleted after development in SAP(fl/fl).tgCreERT2.B6 mice. We find that NKT cell intrinsic expression of SAP is dispensable for noncognate helper functions, but is critical for providing cognate help to antigen-specific B cells. These results demonstrate that SLAM-family receptor-regulated cell-cell interactions are not limited to T-B cell conjugates. We conclude that in the absence of SAP, several routes of NKT cell-mediated antibody production are still accessible. The latter suggests that residual NKT cells in XLP patients might contribute to variations in dysgammaglobulinemia.
Assuntos
Linfócitos B/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/imunologia , Células Matadoras Naturais/imunologia , Transtornos Linfoproliferativos/imunologia , Animais , Antineoplásicos Hormonais/farmacologia , Linfócitos B/citologia , Comunicação Celular/efeitos dos fármacos , Comunicação Celular/imunologia , Feminino , Galactosilceramidas/metabolismo , Galactosilceramidas/farmacologia , Expressão Gênica/imunologia , Centro Germinativo/imunologia , Haptenos/imunologia , Haptenos/metabolismo , Células Matadoras Naturais/citologia , Ativação Linfocitária/efeitos dos fármacos , Ativação Linfocitária/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Proteína Associada à Molécula de Sinalização da Ativação Linfocitária , Tamoxifeno/farmacologiaRESUMO
The Wiskott-Aldrich syndrome protein (WASP) is a key cytoskeletal regulator of hematopoietic cells. Although WASP-knockout (WKO) mice have aberrant B-cell cytoskeletal responses, B-cell development is relatively normal. We hypothesized that N-WASP, a ubiquitously expressed homolog of WASP, may serve some redundant functions with WASP in B cells. In the present study, we generated mice lacking WASP and N-WASP in B cells (conditional double knockout [cDKO] B cells) and show that cDKO mice had decreased numbers of follicular and marginal zone B cells in the spleen. Receptor-induced activation of cDKO B cells led to normal proliferation but a marked reduction of spreading compared with wild-type and WKO B cells. Whereas WKO B cells showed decreased migration in vitro and homing in vivo compared with wild-type cells, cDKO B cells showed an even more pronounced decrease in the migratory response in vivo. After injection of 2,4,6-trinitrophenol (TNP)-Ficoll, cDKO B cells had reduced antigen uptake in the splenic marginal zone. Despite high basal serum IgM, cDKO mice mounted a reduced immune response to the T cell-independent antigen TNP-Ficoll and to the T cell-dependent antigen TNP-keyhole limpet hemocyanin. Our results reveal that the combined activity of WASP and N-WASP is required for peripheral B-cell development and function.
Assuntos
Linfócitos B/citologia , Linfócitos B/fisiologia , Proteína Neuronal da Síndrome de Wiskott-Aldrich/fisiologia , Proteína da Síndrome de Wiskott-Aldrich/fisiologia , Animais , Western Blotting , Movimento Celular , Proliferação de Células , Células Cultivadas , Quimiotaxia , Ficoll/análogos & derivados , Ficoll/farmacologia , Citometria de Fluxo , Hematopoese/fisiologia , Imunização , Técnicas Imunoenzimáticas , Integrases/metabolismo , Camundongos , Camundongos Knockout , Trinitrobenzenos/farmacologiaRESUMO
Wiskott Aldrich syndrome (WAS) is caused by mutations in the WAS gene that encodes for a protein (WASp) involved in cytoskeleton organization in hematopoietic cells. Several distinctive abnormalities of T, B, and natural killer lymphocytes; dendritic cells; and phagocytes have been found in WASp-deficient patients and mice; however, the in vivo consequence of WASp deficiency within individual blood cell lineages has not been definitively evaluated. By conditional gene deletion we have generated mice with selective deficiency of WASp in the B-cell lineage (B/WcKO mice). We show that this is sufficient to cause a severe reduction of marginal zone B cells and inability to respond to type II T-independent Ags, thereby recapitulating phenotypic features of complete WASp deficiency. In addition, B/WcKO mice showed prominent signs of B-cell dysregulation, as indicated by an increase in serum IgM levels, expansion of germinal center B cells and plasma cells, and elevated autoantibody production. These findings are accompanied by hyperproliferation of WASp-deficient follicular and germinal center B cells in heterozygous B/WcKO mice in vivo and excessive differentiation of WASp-deficient B cells into class-switched plasmablasts in vitro, suggesting that WASp-dependent B cell-intrinsic mechanisms critically contribute to WAS-associated autoimmunity.
Assuntos
Linfócitos B/citologia , Linfócitos B/imunologia , Proteína da Síndrome de Wiskott-Aldrich/imunologia , Animais , Autoanticorpos/sangue , Autoanticorpos/imunologia , Autoantígenos/imunologia , Contagem de Células , Modelos Animais de Doenças , Citometria de Fluxo , Imunofluorescência , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína da Síndrome de Wiskott-Aldrich/deficiência , Proteína da Síndrome de Wiskott-Aldrich/genéticaRESUMO
Phagocytosis is a pivotal process by which macrophages eliminate microorganisms after recognition by pathogen sensors. Here we unexpectedly found that the self ligand and cell surface receptor SLAM functioned not only as a costimulatory molecule but also as a microbial sensor that controlled the killing of gram-negative bacteria by macrophages. SLAM regulated activity of the NADPH oxidase NOX2 complex and phagolysosomal maturation after entering the phagosome, following interaction with the bacterial outer membrane proteins OmpC and OmpF. SLAM recruited a complex containing the intracellular class III phosphatidylinositol kinase Vps34, its regulatory protein kinase Vps15 and the autophagy-associated molecule beclin-1 to the phagosome, which was responsible for inducing the accumulation of phosphatidylinositol-3-phosphate, a regulator of both NOX2 function and phagosomal or endosomal fusion. Thus, SLAM connects the gram-negative bacterial phagosome to ubiquitous cellular machinery responsible for the control of bacterial killing.
Assuntos
Antígenos CD/metabolismo , Infecções por Escherichia coli/imunologia , Escherichia coli/imunologia , Macrófagos/imunologia , Fagossomos/imunologia , Receptores de Superfície Celular/metabolismo , Infecções por Salmonella/imunologia , Salmonella typhimurium/imunologia , Animais , Antígenos CD/genética , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas de Bactérias/genética , Proteína Beclina-1 , Células Cultivadas , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Macrófagos/microbiologia , Masculino , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Chaperonas Moleculares/genética , NADPH Oxidase 2 , NADPH Oxidases/metabolismo , Fagocitose , Fagossomos/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Porinas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Receptores de Superfície Celular/genética , Membro 1 da Família de Moléculas de Sinalização da Ativação Linfocitária , Proteína VPS15 de Distribuição VacuolarRESUMO
The contribution of B cells to the pathology of Omenn syndrome and leaky severe combined immunodeficiency (SCID) has not been previously investigated. We have studied a mut/mut mouse model of leaky SCID with a homozygous Rag1 S723C mutation that impairs, but does not abrogate, V(D)J recombination activity. In spite of a severe block at the pro-B cell stage and profound B cell lymphopenia, significant serum levels of immunoglobulin (Ig) G, IgM, IgA, and IgE and a high proportion of Ig-secreting cells were detected in mut/mut mice. Antibody responses to trinitrophenyl (TNP)-Ficoll and production of high-affinity antibodies to TNP-keyhole limpet hemocyanin were severely impaired, even after adoptive transfer of wild-type CD4(+) T cells. Mut/mut mice produced high amounts of low-affinity self-reactive antibodies and showed significant lymphocytic infiltrates in peripheral tissues. Autoantibody production was associated with impaired receptor editing and increased serum B cell-activating factor (BAFF) concentrations. Autoantibodies and elevated BAFF levels were also identified in patients with Omenn syndrome and leaky SCID as a result of hypomorphic RAG mutations. These data indicate that the stochastic generation of an autoreactive B cell repertoire, which is associated with defects in central and peripheral checkpoints of B cell tolerance, is an important, previously unrecognized, aspect of immunodeficiencies associated with hypomorphic RAG mutations.
Assuntos
Células Produtoras de Anticorpos/imunologia , Células Produtoras de Anticorpos/patologia , Linfócitos B/imunologia , Linfócitos B/patologia , Proteínas de Homeodomínio/imunologia , Tolerância Imunológica/imunologia , Animais , Formação de Anticorpos/imunologia , Autoanticorpos/sangue , Fator Ativador de Células B/sangue , Proliferação de Células , Proteínas de Homeodomínio/genética , Humanos , Imunidade/imunologia , Imunização , Síndromes de Imunodeficiência/sangue , Síndromes de Imunodeficiência/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Mutação/genética , Baço/imunologia , Baço/patologiaRESUMO
DNA ligase IV (LIG4) is an essential component of the nonhomologous end-joining (NHEJ) repair pathway and plays a key role in V(D)J recombination. Hypomorphic LIG4 mutations in humans are associated with increased cellular radiosensitivity, microcephaly, facial dysmorphisms, growth retardation, developmental delay, and a variable degree of immunodeficiency. We have generated a knock-in mouse model with a homozygous Lig4 R278H mutation that corresponds to the first LIG4 mutation reported in humans. The phenotype of homozygous mutant mice Lig4(R278H/R278H) (Lig4(R/R)) includes growth retardation, a decreased life span, a severe cellular sensitivity to ionizing radiation, and a very severe, but incomplete block in T and B cell development. Peripheral T lymphocytes show an activated and anergic phenotype, reduced viability, and a restricted repertoire, reminiscent of human leaky SCID. Genomic instability is associated with a high rate of thymic tumor development. Finally, Lig4(R/R) mice spontaneously produce low-affinity antibodies that include autoreactive specificities, but are unable to mount high-affinity antibody responses. These findings highlight the importance of LIG4 in lymphocyte development and function, and in genomic stability maintenance, and provide a model for the complex phenotype of LIG4 syndrome in humans.
Assuntos
Anormalidades Múltiplas/genética , Formação de Anticorpos/genética , DNA Ligases/genética , Deficiências do Desenvolvimento/genética , Modelos Animais de Doenças , Mutação de Sentido Incorreto/genética , Imunodeficiência Combinada Severa/genética , Animais , Apoptose/imunologia , Southern Blotting , Criança , DNA Ligase Dependente de ATP , DNA Ligases/imunologia , Citometria de Fluxo , Humanos , Imunoglobulinas/sangue , Imunofenotipagem , Camundongos , Mutação de Sentido Incorreto/imunologia , SíndromeRESUMO
One or more of the signaling lymphocytic activation molecule (SLAM) family (SLAMF) of cell surface receptors, which consists of nine transmembrane proteins, i.e., SLAMF1-9, are expressed on most hematopoietic cells. While most SLAMF receptors serve as self-ligands, SLAMF2 and SLAMF4 use each other as counter structures. Six of the receptors carry one or more copies of a unique intracellular tyrosine-based switch motif, which has high affinity for the single SH2-domain signaling molecules SLAM-associated protein and EAT-2. Whereas SLAMF receptors are costimulatory molecules on the surface of CD4+, CD8+, and natural killer (NK) T cells, they also involved in early phases of lineage commitment during hematopoiesis. SLAMF receptors regulate T lymphocyte development and function and modulate lytic activity, cytokine production, and major histocompatibility complex-independent cell inhibition of NK cells. Furthermore, they modulate B cell activation and memory generation, neutrophil, dendritic cell, macrophage and eosinophil function, and platelet aggregation. In this review, we will discuss the role of SLAM receptors and their adapters in T cell function, and we will examine the role of these receptors and their adapters in X-linked lymphoproliferative disease and their contribution to disease susceptibility in systemic lupus erythematosus.
Assuntos
Antígenos CD/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/imunologia , Receptores de Superfície Celular/imunologia , Linfócitos T/imunologia , Animais , Antígenos CD/genética , Antígenos CD/metabolismo , Diferenciação Celular/imunologia , Predisposição Genética para Doença , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/imunologia , Ativação Linfocitária/genética , Ativação Linfocitária/imunologia , Transtornos Linfoproliferativos/genética , Transtornos Linfoproliferativos/imunologia , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Proteína Associada à Molécula de Sinalização da Ativação Linfocitária , Membro 1 da Família de Moléculas de Sinalização da Ativação Linfocitária , Linfócitos T/citologia , Linfócitos T/metabolismoRESUMO
PURPOSE: To identify radiation-induced early transcriptional responses in primary human fibroblasts and understand cellular pathways leading to damage correction. METHODS AND MATERIALS: Primary human fibroblast cell lines were irradiated with 2 Gy gamma-radiation and RNA isolated 2 h later. Radiation-induced transcriptional alterations were investigated with microarrays covering the entire human genome. Time- and dose dependent radiation responses were studied by quantitative real-time polymerase chain reaction (RT-PCR). RESULTS: About 200 genes responded to ionizing radiation on the transcriptional level in primary human fibroblasts. The expression profile depended on individual genetic backgrounds. Thirty genes (28 up- and 2 down-regulated) responded to radiation in identical manner in all investigated cells. Twenty of these consensus radiation response genes were functionally categorized: most of them belong to the DNA damage response (GADD45A, BTG2, PCNA, IER5), regulation of cell cycle and cell proliferation (CDKN1A, PPM1D, SERTAD1, PLK2, PLK3, CYR61), programmed cell death (BBC3, TP53INP1) and signaling (SH2D2A, SLIC1, GDF15, THSD1) pathways. Four genes (SEL10, FDXR, CYP26B1, OR11A1) were annotated to other functional groups. Many of the consensus radiation response genes are regulated by, or regulate p53. Time- and dose-dependent expression profiles of selected consensus genes (CDKN1A, GADD45A, IER5, PLK3, CYR61) were investigated by quantitative RT-PCR. Transcriptional alterations depended on the applied dose, and on the time after irradiation. CONCLUSIONS: The data presented here could help in the better understanding of early radiation responses and the development of biomarkers to identify radiation susceptible individuals.
Assuntos
Fibroblastos/efeitos da radiação , Perfilação da Expressão Gênica , Análise de Sequência com Séries de Oligonucleotídeos , Idoso , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Criança , Dano ao DNA , Relação Dose-Resposta à Radiação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Fatores de Tempo , Transcrição GênicaRESUMO
Several data indicate a connection between Chlamydophila pneumoniae infection and asthma. Although C. pneumoniae is a common cause of infection, not all infected patients develop asthma. This suggests that certain individuals may be genetically predisposed to the chronic effects of C. pneumoniae infection on airway functions. We investigated the possible modifying effect of different polymorphisms on C. pneumoniae infection and on the susceptibility to asthma in 318 children, among those 144 had asthma and 174 had no asthmatic symptoms. C. pneumoniae-specific antibodies were measured by ELISA. Tumor necrosis factor-alpha (TNFalpha), monocyte chemoattractant protein-1 (MCP-1), and RANTES (regulated on activation normal T cell expressed and secreted) genotypes were determined by PCR-restriction fragment length polymorphism (RFLP). There were no significant differences in the percentage of children positive for C. pneumoniae-specific antibodies between cases and controls. None of the genotypes was associated with altered susceptibility to C. pneumoniae infection. Among asthmatic children carrying the TNFalpha -308A allele, there were significantly more patients positive for C. pneumoniae-specific IgG, than among control children carrying the same allele (20.1% versus 9.2% of asthmatic versus control children, respectively; p = 0.002; odds ratio = 3.52 (1.52-7.53); p = 0.005). This study indicates the possible roles of polymorphisms in the immune system in the susceptibility to asthma in children infected with C. pneumoniae.