RESUMEN
Cancer cells subvert immune surveillance through inhibition of T cell effector function. Elucidation of the mechanism of T cell dysfunction is therefore central to cancer immunotherapy. Here, we report that dual specificity phosphatase 2 (DUSP2; also known as phosphatase of activated cells 1, PAC1) acts as an immune checkpoint in T cell antitumor immunity. PAC1 is selectively upregulated in exhausted tumor-infiltrating lymphocytes and is associated with poor prognosis of patients with cancer. PAC1hi effector T cells lose their proliferative and effector capacities and convert into exhausted T cells. Deletion of PAC1 enhances immune responses and reduces cancer susceptibility in mice. Through activation of EGR1, excessive reactive oxygen species in the tumor microenvironment induce expression of PAC1, which recruits the Mi-2ß nucleosome-remodeling and histone-deacetylase complex, eventually leading to chromatin remodeling of effector T cells. Our study demonstrates that PAC1 is an epigenetic immune regulator and highlights the importance of targeting PAC1 in cancer immunotherapy.
Asunto(s)
Fosfatasa 2 de Especificidad Dual/inmunología , Neoplasias/inmunología , Linfocitos T/inmunología , Animales , Cromatina/genética , Cromatina/metabolismo , Fosfatasa 2 de Especificidad Dual/deficiencia , Fosfatasa 2 de Especificidad Dual/genética , Proteína 1 de la Respuesta de Crecimiento Precoz/metabolismo , Femenino , Humanos , Activación de Linfocitos , Linfocitos Infiltrantes de Tumor/inmunología , Masculino , Complejo Desacetilasa y Remodelación del Nucleosoma Mi-2/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Ratones Noqueados , Ratones SCID , Neoplasias/genética , Neoplasias/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Microambiente Tumoral/genética , Microambiente Tumoral/inmunología , Regulación hacia ArribaRESUMEN
Dual-specificity MAP kinase (MAPK) phosphatases (DUSPs) are well-established negative modulators in regulating MAPK signaling in mammalian cells and tissues. Our previous studies have shown the involvement of DUSP6 in regulating innate immunity in Japanese flounder Paralichthys olivaceus. In order to gain a better understanding of the role of DUSPs in fish innate immunity, in the present study we identified and characterized three additional DUSP genes including DUSP1, 2 and 5 in P. olivaceus. The three Japanese flounder DUSP proteins share common domain structures composed of a conserved N-terminal Rhodanase/CDC25 domain and a C-terminal catalytic phosphatase domain, while they show only less than 26% sequence identities, indicating that they may have different substrate selectivity. In addition, mRNA transcripts of all the three DUSP genes are detected in all examined Japanese flounder tissues; however, DUSP1 is dominantly expressed in spleen while DUSP2 and 5 are primarily expressed in skin. Furthermore, all the three DUSP genes are constitutively expressed in the Japanese flounder head kidney macrophages (HKMs) and peripheral blood leucocytes (PBLs) with unequal distribution patterns. Moreover, all the three DUSPs gene expression was induced differently in response to the LPS and double-stranded RNA mimic poly(I:C) stimulations both in the Japanese flounder HKMs and PBLs, suggesting an association of DUSPs with TLR signaling in fish. Taken together, the co-expression of various DUSPs members together with their different responses to the immune challenges indicate that the DUSP members may operate coordinately in regulating the MAPK-dependent immune responses in the Japanese flounder.
Asunto(s)
Fosfatasas de Especificidad Dual/genética , Proteínas de Peces/genética , Peces Planos/genética , Peces Planos/inmunología , Regulación de la Expresión Génica/inmunología , Inmunidad Innata/genética , Secuencia de Aminoácidos , Animales , Técnicas de Cultivo de Célula , Fosfatasa 1 de Especificidad Dual/química , Fosfatasa 1 de Especificidad Dual/genética , Fosfatasa 1 de Especificidad Dual/inmunología , Fosfatasa 1 de Especificidad Dual/metabolismo , Fosfatasa 2 de Especificidad Dual/química , Fosfatasa 2 de Especificidad Dual/genética , Fosfatasa 2 de Especificidad Dual/inmunología , Fosfatasa 2 de Especificidad Dual/metabolismo , Fosfatasas de Especificidad Dual/química , Fosfatasas de Especificidad Dual/inmunología , Fosfatasas de Especificidad Dual/metabolismo , Proteínas de Peces/química , Proteínas de Peces/inmunología , Regulación de la Expresión Génica/efectos de los fármacos , Lipopolisacáridos/farmacología , Filogenia , Poli I-C/farmacología , Alineación de Secuencia/veterinariaRESUMEN
Deregulation of the TH17 subset of helper T cells is closely linked with immunological disorders and inflammatory diseases. However, the mechanism by which TH17 cells are regulated remains elusive. Here we found that the phosphatase DUSP2 (PAC1) negatively regulated the development of TH17 cells. DUSP2 was directly associated with the signal transducer and transcription activator STAT3 and attenuated its activity through dephosphorylation of STAT3 at Tyr705 and Ser727. DUSP2-deficient mice exhibited severe susceptibility to experimental colitis, with enhanced differentiation of TH17 cells and secretion of proinflammatory cytokines. In clinical patients with ulcerative colitis, DUSP2 was downregulated by DNA methylation and was not induced during T cell activation. Our data demonstrate that DUSP2 is a true STAT3 phosphatase that modulates the development of TH17 cells in the autoimmune response and inflammation.
Asunto(s)
Diferenciación Celular/inmunología , Fosfatasa 2 de Especificidad Dual/inmunología , Factor de Transcripción STAT3/inmunología , Células Th17/inmunología , Animales , Células Cultivadas , Colitis/inducido químicamente , Colitis/genética , Colitis/inmunología , Colitis Ulcerosa/genética , Colitis Ulcerosa/inmunología , Colitis Ulcerosa/metabolismo , Citocinas/inmunología , Citocinas/metabolismo , Metilación de ADN/inmunología , Sulfato de Dextran , Fosfatasa 2 de Especificidad Dual/deficiencia , Fosfatasa 2 de Especificidad Dual/genética , Regulación de la Expresión Génica/inmunología , Células HEK293 , Humanos , Immunoblotting , Mediadores de Inflamación/inmunología , Mediadores de Inflamación/metabolismo , Ratones Endogámicos C57BL , Ratones Noqueados , Fosforilación/inmunología , Unión Proteica/inmunología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factor de Transcripción STAT3/metabolismo , Células Th17/metabolismo , Tirosina/inmunología , Tirosina/metabolismoRESUMEN
Dual-specificity phosphatase 2 (Dusp2; also called phosphatase of activated cells 1, PAC1) is highly expressed in activated immune cells. We examined whether a potential inhibitor of Dusp2, salubrinal, prevents inflammatory cytokine expression in immune cells and arthritic responses in a mouse model of anti-collagen antibody-induced arthritis (CAIA). Salubrinal is a synthetic chemical that inhibits de-phosphorylation of eukaryotic translation initiation factor 2 alpha (eIF2α). In this study, we examined the effects of salubrinal on expression of inflammation linked genes as well as a family of DUSP genes using genome-wide microarrays, qPCR, and RNA interference. We also evaluated the effects of salubrinal on arthritic responses in CAIA mice using clinical and histological scores. The results revealed that salubrinal decreased inflammatory gene expression in macrophages, T lymphocytes, and mast cells. Dusp2 was suppressed by salubrinal in LPS-activated macrophages as well as PMA/ionomycin-activated T lymphocytes and mast cells. Furthermore, a partial silencing of Dusp2 downregulated IL1ß and Cox2, and the inflammatory signs of CAIA mice were significantly suppressed by salubrinal. Collectively, this study presents a novel therapeutic possibility of salubrinal for inflammatory arthritis such as RA through inhibition of Dusp2.
Asunto(s)
Antiinflamatorios/uso terapéutico , Artritis Experimental/tratamiento farmacológico , Cinamatos/uso terapéutico , Fosfatasa 2 de Especificidad Dual/antagonistas & inhibidores , Tiourea/análogos & derivados , Animales , Artritis Experimental/genética , Artritis Experimental/inmunología , Artritis Experimental/patología , Línea Celular , Citocinas/genética , Citocinas/inmunología , Fosfatasa 2 de Especificidad Dual/genética , Fosfatasa 2 de Especificidad Dual/inmunología , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Inflamación/tratamiento farmacológico , Inflamación/genética , Inflamación/inmunología , Inflamación/patología , Interleucina-1beta/genética , Interleucina-1beta/inmunología , Ratones , Ratones Endogámicos BALB C , Interferencia de ARN , Tiourea/uso terapéuticoRESUMEN
Dual-specificity phosphatases (DUSPs) is an emerging subclass of the protein tyrosine phosphatase gene superfamily, a heterogeneous group of protein phosphatases that can dephosphorylate both phosphotyrosine and phosphoserine/phosphothreonine residues within the one substrate. Recently, a series of investigations of DUSPs defined their essential roles in cell proliferation, cancer and the immune response. This review will focus on DUSP2, its involvement in different diseases and its potential as a therapeutic target.
Asunto(s)
Fosfatasa 2 de Especificidad Dual/metabolismo , Inmunidad Adaptativa , Animales , Biomarcadores , Fosfatasa 2 de Especificidad Dual/genética , Fosfatasa 2 de Especificidad Dual/inmunología , Humanos , Infecciones/diagnóstico , Infecciones/genética , Infecciones/metabolismo , Inflamación/diagnóstico , Inflamación/genética , Inflamación/metabolismo , Sistema de Señalización de MAP Quinasas , Neoplasias/diagnóstico , Neoplasias/genética , Neoplasias/metabolismoRESUMEN
BACKGROUND: Multiparameter flow cytometric analysis of bone marrow and peripheral blood cells has proven to be of help in the diagnostic workup of myelodysplastic syndromes. However, the usefulness of flow cytometry for the detection of megakaryocytic and platelet dysplasia has not yet been investigated. The aim of this pilot study was to evaluate by flow cytometry the diagnostic and prognostic value of platelet dysplasia in myelodysplastic syndromes. DESIGN AND METHODS: We investigated the pattern of expression of distinct surface glycoproteins on peripheral blood platelets from a series of 44 myelodysplastic syndrome patients, 20 healthy subjects and 19 patients with platelet alterations associated to disease conditions other than myelodysplastic syndromes. Quantitative expression of CD31, CD34, CD36, CD41a, CD41b, CD42a, CD42b and CD61 glycoproteins together with the PAC-1, CD62-P, fibrinogen and CD63 platelet activation-associated markers and platelet light scatter properties were systematically evaluated. RESULTS: Overall, flow cytometry identified multiple immunophenotypic abnormalities on platelets of myelodysplastic syndrome patients, including altered light scatter characteristics, over-and under expression of specific platelet glycoproteins and asynchronous expression of CD34; decreased expression of CD36 (n = 5), CD42a (n = 1) and CD61 (n = 2), together with reactivity for CD34 (n = 1) were only observed among myelodysplastic syndrome cases, while other alterations were also found in other platelet disorders. Based on the overall platelet alterations detected for each patient, an immunophenotypic score was built which identified a subgroup of myelodysplastic syndrome patients with a high rate of moderate to severe alterations (score>1.5; n = 16) who more frequently showed thrombocytopenia, megakaryocytic dysplasia and high-risk disease, together with a shorter overall survival. CONCLUSIONS: Our results show the presence of altered phenotypes by flow cytometry on platelets from around half of the myelodysplastic syndrome patients studied. If confirmed in larger series of patients, these findings may help refine the diagnostic and prognostic assessment of this group of disorders.