RESUMO
BACKGROUND/OBJECTIVES: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are medical emergencies. Mainstays of treatment include removal of the offending agent, supportive care, and wound care. The use of immunosuppressive agents such as corticosteroids and intravenous immunoglobulin (IVIg) is controversial. Some case reports and small studies report the successful use of cyclosporin A (CsA) for SJS/TEN in halting disease progression, fostering reepithelialization, and reducing mortality. OBJECTIVE: To report on the efficacy of cyclosporine A in the treatment of SJS/TEN in three pediatric patients. METHODS: We describe three pediatric patients seen at a tertiary care hospital in Boston, Massachusetts, diagnosed with SJS/TEN confirmed by skin biopsy who were successfully treated with CsA with improvements seen in time to cessation of disease progression or new lesion formation, reepithelialization, and duration of hospital stay. RESULTS: The average time cessation of disease progression or new lesion formation after CsA administration was 2.2 days (range 1.5-3 days) and average time to remission or reepithelialization was 13 days (range 10-15 days). The average length of hospital stay was 11.7 days (range 4-19 days). CONCLUSIONS: We describe three pediatric patients treated successfully with CsA and provide evidence for the use of cyclosporine in children with SJS/TEN. These results further support previous observations that CsA use for SJS/TEN produces consistently favorable outcomes. The results in this case series are limited by their observational nature. Additional trials are needed to evaluate the safety and efficacy of CsA use in children.
Assuntos
Ciclosporina/uso terapêutico , Imunossupressores/uso terapêutico , Síndrome de Stevens-Johnson/tratamento farmacológico , Boston , Criança , Pré-Escolar , Progressão da Doença , Feminino , Humanos , Lactente , Tempo de Internação/estatística & dados numéricos , Masculino , Pele/patologia , Fatores de Tempo , Resultado do TratamentoRESUMO
IL-17 mediates essential inflammatory responses in host defense and autoimmunity. The IL-17A-IL-17F signaling complex is composed of IL-17RA and IL-17RC, both of which are necessary for signal transduction. To date, the specific contribution of IL-17RC to downstream signaling remains poorly understood. To define the regions within the IL-17RC cytoplasmic tail required for signal transduction, we assayed signaling by a panel of IL-17RC deletion mutants. These findings reveal that IL-17RC inducibly associates with a specific glycosylated IL-17RA isoform, in a manner independent of the IL-17RC cytoplasmic tail. Using expression of the IL-17 target genes IL-6 and 24p3/lipocalin-2 as a readout, functional reconstitution of signaling in IL-17RC(-/-) fibroblasts required the SEF/IL-17R signaling domain (SEFIR), a conserved motif common to IL-17R family members. Unexpectedly, the IL-17RC SEFIR alone was not sufficient to reconstitute IL-17-dependent signaling. Rather, an additional sequence downstream of the SEFIR was also necessary. We further found that IL-17RC interacts directly with the adaptor/E3 ubiquitin ligase Act1, and that the functional IL-17RC isoforms containing the extended SEFIR region interact specifically with a phosphorylated isoform of Act1. Finally, we show that IL-17RC is required for in vivo IL-17-dependent responses during oral mucosal infections caused by the human commensal fungus Candida albicans. These results indicate that IL-17RC is vital for IL-17-dependent signaling both in vitro and in vivo. Insight into the mechanisms by which IL-17RC signals helps shed light on IL-17-dependent inflammatory responses and may ultimately provide an avenue for therapeutic intervention in IL-17-mediated diseases.
Assuntos
Motivos de Aminoácidos , Fibroblastos/imunologia , Receptores de Interleucina-17/imunologia , Transdução de Sinais/imunologia , Sequência de Aminoácidos , Animais , Sítios de Ligação , Western Blotting , Candidíase Bucal/genética , Candidíase Bucal/imunologia , Linhagem Celular , Células Cultivadas , Modelos Animais de Doenças , Fibroblastos/citologia , Fibroblastos/metabolismo , Citometria de Fluxo , Predisposição Genética para Doença , Humanos , Interleucina-17/farmacologia , Camundongos , Camundongos Knockout , Mutação , Orofaringe/imunologia , Orofaringe/microbiologia , Ligação Proteica , Isoformas de Proteínas/genética , Isoformas de Proteínas/imunologia , Isoformas de Proteínas/metabolismo , Receptores de Interleucina-17/genética , Receptores de Interleucina-17/metabolismo , Transdução de Sinais/efeitos dos fármacos , TransfecçãoRESUMO
IL-17, the hallmark cytokine of the Th17 population, mediates immunity to extracellular pathogens and promotes autoimmune immunopathology. The signaling mechanisms triggered by the IL-17 receptor (IL-17RA) and related receptors are strikingly different from other cytokine subclasses. Namely, IL-17Rs contain a conserved SEF/IL-17R (SEFIR) subdomain that engages Act1, leading to activation of TRAF6, NF-κB, and other events. Although the SEFIR is critical for signaling, the molecular details of the functional subdomains within IL-17RA remain poorly characterized. Here, we provide a detailed structure-function analysis delineating the C-terminal boundary of the SEFIR-containing region of IL-17RA. We show that functionality of this domain requires a large extension to the previously identified SEFIR motif. In contrast to the SEFIR, this extension is not conserved among IL-17R family members. Surprisingly, Act1 recruitment is not sufficient for downstream signaling activation, whereas ubiquitination of TRAF6 correlates tightly with functional receptors. We further demonstrate that IL-17RA exhibits signaling properties that are nonredundant with other IL-17R family members. Finally, we report that IL-17 signals synergistically with lymphotoxin-α3, using the same signaling motifs within IL-17RA. These studies provide new insight into the structure-function relationships of IL-17RA and reveal distinct signaling differences among IL-17R family members.
Assuntos
Receptores de Interleucina-17/metabolismo , Transdução de Sinais/fisiologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Motivos de Aminoácidos , Animais , Humanos , Interleucina-17/metabolismo , Linfotoxina-alfa/genética , Linfotoxina-alfa/metabolismo , Camundongos , Camundongos Knockout , NF-kappa B/genética , NF-kappa B/metabolismo , Estrutura Terciária de Proteína , Receptores de Interleucina-17/genética , Fator 6 Associado a Receptor de TNF/genética , Fator 6 Associado a Receptor de TNF/metabolismo , Peptídeos e Proteínas Associados a Receptores de Fatores de Necrose Tumoral/genética , Peptídeos e Proteínas Associados a Receptores de Fatores de Necrose Tumoral/metabolismo , Ubiquitinação/fisiologiaRESUMO
Waldenstrom macroglobulinemia (WM) is an incurable low-grade lymphoma characterized by bone marrow (BM) involvement of IgM secreting lymphoplasmacytic cells. The induction of unfolded protein response (UPR) genes ("physiologic" UPR) enables cells to differentiate into professional secretory cells capable of production of high amounts of endoplasmic reticulum (ER)-processed proteins, such as immunoglobulins. Ultimately, the initially cytoprotective UPR triggers an apoptotic cascade if ER stress is not corrected, called proapoptotic/terminal UPR. We show that WM cells inherently express the physiologic UPR machinery compared with normal BM cells, and that increased ER stress leads to proapoptotic/terminal UPR in WM cells. We therefore examined tunicamycin, ER stress inducer, for potential antitumor effects in WM. Tunicamycin induced significant cytotoxicity, apoptosis and cell-cycle arrest, and inhibited DNA synthesis in WM cell lines and primary BM CD19(+) cells from patients with WM with an inhibitory concentration (IC(50)) of 0.5 microg/mL to 1 microg/mL, but not in healthy donor cells. Importantly, coculture of WM cells in the context of the BM microenvironment did not inhibit tunicamycin-induced cytotoxicity. Finally, we demonstrate that ER stress inducer synergizes with other agents used in the treatment of WM. These preclinical studies provide a framework for further evaluation of ER stress inducing agents as therapeutic agents in WM.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Retículo Endoplasmático/efeitos dos fármacos , Tunicamicina/farmacologia , Macroglobulinemia de Waldenstrom/tratamento farmacológico , Apoptose/fisiologia , Linfócitos B/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Retículo Endoplasmático/patologia , Citometria de Fluxo , Expressão Gênica , Humanos , Immunoblotting , Dobramento de Proteína/efeitos dos fármacos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Estresse Fisiológico , Macroglobulinemia de Waldenstrom/genética , Macroglobulinemia de Waldenstrom/patologiaRESUMO
Waldenström macroglobulinemia (WM) is a B-cell malignancy characterized by an IgM monoclonal gammopathy and bone marrow (BM) infiltration with lymphoplasmacytic cells (LPCs). Excess mast cells (MCs) are commonly present in WM, and provide growth and survival signals to LPCs through several TNF family ligands (CD40L, a proliferation-inducing ligand [APRIL], and B-lymphocyte stimulator factor [BLYS]). As part of these studies, we demonstrated that WM LPCs secrete soluble CD27 (sCD27), which is elevated in patients with WM (P < .001 vs healthy donors), and serves as a faithful marker of disease. Importantly, sCD27 stimulated expression of CD40L on 10 of 10 BM MC samples and APRIL on 4 of 10 BM MC samples obtained from patients with WM as well as on LAD2 MCs. Moreover, the SGN-70 humanized monoclonal antibody, which binds to CD70 (the receptor-ligand partner of CD27), abrogated sCD27 mediated up-regulation of CD40L and APRIL on WM MCs. Last, treatment of severe combined immunodeficiency-human (SCID-hu) mice with established WM using the SGN-70 antibody blocked disease progression in 12 of 12 mice, whereas disease progressed in all 5 untreated mice. The results of these studies demonstrate a functional role for sCD27 in WM pathogenesis, along with its utility as a surrogate marker of disease and a target in the treatment of WM.
Assuntos
Ligante CD27/metabolismo , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismo , Macroglobulinemia de Waldenstrom/etiologia , Animais , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais/uso terapêutico , Biomarcadores Tumorais/metabolismo , Ligante CD27/imunologia , Ligante CD27/fisiologia , Estudos de Casos e Controles , Células Cultivadas , Humanos , Mastócitos/metabolismo , Mastócitos/patologia , Camundongos , Camundongos SCID , Plasmócitos/metabolismo , Plasmócitos/patologia , Ligação Proteica , Carga Tumoral , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/fisiologia , Macroglobulinemia de Waldenstrom/metabolismo , Macroglobulinemia de Waldenstrom/patologia , Macroglobulinemia de Waldenstrom/terapia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
CD4+T helper (Th) cells are critical in homeostasis and host defense but are also central to the development of various autoimmune diseases if they become dysregulated. Specifically, pathogenic Th1 and Th17 cells contribute to autoimmune inflammation whereas Treg and Tr1 cells are important for maintaining immune tolerance and resolution of inflammation, respectively. Cytokines trigger signaling pathways in naive T cells that induce lineage-defining transcription factors that direct their differentiation into the distinct T helper cell subsets. It has become clear that the differentiation of T helper cells is not only influenced by the cytokine milieu but also by their metabolic state, cues from the microbiota and the tissue they reside in. A comprehensive understanding how these various stimuli contribute to T helper cell differentiation and phenotype could potentially provide novel ways for therapeutic intervention in autoimmunity and tissue inflammation.
Assuntos
Autoimunidade/imunologia , Linfócitos T CD4-Positivos/imunologia , Citocinas/imunologia , Inflamação/imunologia , Fatores de Transcrição/imunologia , Animais , Diferenciação Celular/imunologia , HumanosRESUMO
Waldenstrom Macroglobulinemia (WM) is a B-cell malignancy characterized by excess bone marrow (BM) lymphoplasmacytic cells (LPC). The accumulation of LPC in WM may represent a failure of B-cells to properly differentiate into plasma cells. The present study investigated transcriptional expression of genes involved in late B-cell differentiation, including PRDM1, PAX5, XBP1 transcripts and ERN1, in BM B-cells from 31 patients with WM and six healthy donors. Real time reverse transcription polymerase chain reaction (RT-PCR) determined that approximately 80% of the patients had high XBP1 spliced mRNA expression, 80% of whom had high mRNA ERN1alpha expression. XBP1, PRDM1 and PAX5 mRNA was present in all patients studied. Using relative quantitative RT-PCR we isolated two groups with low and high expression of XBP1, XBP1 spliced and ERN1alpha. Sequence analysis showed germline polymorphisms in all genes studied. These data depict for the first time a heterogeneous expression pattern of the genes involved in late differentiation process of plasma cells in patients with WM and propose a role of XBP1-ERN1alpha in WM pathogenesis.
Assuntos
Linfócitos B/metabolismo , Genes Reguladores , Plasmócitos/metabolismo , Macroglobulinemia de Waldenstrom/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Linfócitos B/patologia , Estudos de Casos e Controles , Diferenciação Celular/genética , Eletroforese Capilar , Feminino , Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Plasmócitos/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Análise de Sequência de DNA , Estatísticas não Paramétricas , Macroglobulinemia de Waldenstrom/patologiaAssuntos
Melanose/patologia , Boca/patologia , Adulto , Biópsia , Diagnóstico Diferencial , Feminino , Humanos , Visitas de PreceptoriaRESUMO
Skin is our primary interface with the environment, and T cells are crucial for orchestrating host immune responses against pathogenic microorganisms at this site. Effective skin immune responses require the generation of antigen-specific effector T cells, which home to cutaneous sites of injury or infection. Long-lasting immunity against future immune challenges is mediated by memory T cells. Among the memory T cells found in skin are both recirculating cells that transit between skin and blood and tissue-resident memory T (TRM) cells, which remain in skin for long periods of time and mediate durable protective immunity. These TRM cells also appear to drive many inflammatory diseases of skin. Here, we consider how a better understanding of cutaneous T cell responses can aid in the development of effective new therapies for immune-mediated cutaneous diseases.
Assuntos
Memória Imunológica , Inflamação/imunologia , Dermatopatias/imunologia , Pele/imunologia , Linfócitos T/imunologia , Animais , HumanosRESUMO
OBJECTIVES: Waldenstrom Macroglobulinemia (WM) is a B-cell neoplasm characterised by secretion of IgM by lymphoplasmacytic bone marrow cells and by cytopenias and hypogammaglobulinemia in a subset of patients. Beta-2 microglobulin (b2m) is a major prognostic factor in WM and the heavy chain of HLA class I molecules, which are known to have immunosuppressive properties and have been implicated in the pathogeny of several malignancies. METHODS: We assessed the serum levels of the total soluble HLA-I molecules and the HLA-Gs molecules in 105 patients with IgM-related disorders [WM (n = 42) and IgM MGUS (n = 63)], and compared the results to 41 healthy subjects. RESULTS: We found higher levels of HLA-Is in WM, compared to IgM MGUS and healthy donors. HLA-Gs levels were similar in WM and in IgM MGUS, but higher than in healthy donors. The association between HLA-Is at the cut-off of 1.8 microg/mL and known markers of poor prognosis was then evaluated among WM patients using univariate and multivariate methods. Based on this, high HLA-Is level was strongly associated with high serum beta2M level >3 mg/L [OR = 2, (CI 95% 1.1-5.7); P = 0.04], age > 65 yrs [OR = 1.5, (CI 95% 0.5-4.1), P = 0.06] and haemoglobin < or =11.5 g/dL [OR = 3.3, (CI 95% 1.2-9.7); P = 0.03]. High levels of serum HLA-Is were also found in patients with cryoglobulinemia, however irrespectively of WM or IgM-MGUS status. CONCLUSION: Together our results suggest a possible role for soluble MHC class I molecules in WM disease. Further investigations are necessary to further demonstrate the prognostic impact of soluble MHC class I molecules in Waldenstrom Macroglobulinemia.
Assuntos
Antígenos de Histocompatibilidade Classe I/imunologia , Macroglobulinemia de Waldenstrom/imunologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , PrognósticoRESUMO
A significant impairment in understanding the biology and advancing therapeutics for Waldenstrom's macroglobulinemia (WM) has been the lack of a representative cell line and animal model. We, therefore, report on the establishment of the BCWM.1 cell line, which was derived from the long-term culture of CD19(+) selected bone marrow lymphoplasmacytic cells isolated from an untreated patient with WM. BCWM.1 cells morphologically resemble lymphoplasmacytic cells (LPC) and propagate in RPMI-1640 medium supplemented with 10% fetal bovine serum. Phenotypic characterization by flow cytometric analysis demonstrated typical WM LPC characteristics: CD5(-), CD10(-), CD19(+), CD20(+), CD23(+), CD27(-), CD38(+), CD138(+), CD40(+), CD52(+), CD70(+), CD117(+), cIgM(+), cIgG(-), cIgA(-), ckappa(-), clambda(+), as well as the survival proteins APRIL and BLYS, and their receptors TACI, BCMA and BAFF-R. Enzyme-linked immunosorbent assay studies demonstrated secretion of IgMlambda and soluble CD27. Karyotypic and multicolor fluorescence in situ hybridization studies did not demonstrate cytogenetic abnormalities. Molecular analysis of BCWM.1 cells confirmed clonality by determination of IgH rearrangements. Inoculation of BCWM.1 cells in human bone marrow chips implanted in severe combined immunodeficient-hu mice led to rapid engraftment of tumor cells and serum detection of human IgM, lambda, and soluble CD27. These studies support the use of BCWM.1 cells as an appropriate model for the study of WM, which in conjunction with the severe combined immunodeficient-hu mouse model may be used as a convenient model for studies focused on both WM pathogenesis and development of targeted therapies for WM.
Assuntos
Linhagem Celular , Modelos Animais de Doenças , Transplante Heterólogo , Macroglobulinemia de Waldenstrom/patologia , Animais , Células Cultivadas , Sobrevivência de Enxerto , Humanos , Camundongos , Camundongos SCID , Camundongos TransgênicosRESUMO
BACKGROUND: Polymorphisms in FcgammaRIIa and FcgammaRIIIa receptors are associated with responses to the CD20-directed immunoglobulin G1 (IgG1) monoclonal antibody rituximab among patients with indolent lymphoma. At odds with the aforementioned clinical observations has been the finding that IgG1 binding is impacted by polymorphisms in FcgammaRIIIa but not FcgammaRIIa. One possibility for this discrepancy might involve linkage of polymorphisms between FcgammaRIIa and FcgammaRIIIa. MATERIALS AND METHODS: As such, we performed allelespecific polymerase chain reaction and directed sequencing of the genomic DNA coding region of FcgammaRIIA and FcgammaRIIIA for 52 healthy individuals. RESULTS: Two common polymorphisms were observed for FcgammaRIIA (at positions 27 and 131) and FcgammaRIIIA (at positions 48 and 158). Importantly, we observed linkage among polymorphisms within and between FcgammaRIIa and FcgammaRIIIa, including the expression of histidine at FcgammaRIIa-131 and valine at FcgammaRIIIa, both of which are associated with enhanced responses to rituximab. The results of these studies demonstrate that there is wide linkage within and between polymorphisms in FcgammaRIIa and FcgammaRIIIa and might provide an explanation for why polymorphisms at FcgammaRIIa are associated with rituximab responses despite a lack of impact on IgG1 binding. CONCLUSION: Knowledge of such linkages could facilitate the development of diagnostic tests aimed at identifying patients who might be more suitable for treatment with rituximab and possibly other therapeutic antibodies.
Assuntos
Anticorpos Monoclonais/uso terapêutico , Antígenos CD20/imunologia , Antígenos CD/genética , Ligação Genética , Linfoma não Hodgkin/tratamento farmacológico , Receptores de IgG/genética , Adulto , Idoso , Anticorpos Monoclonais Murinos , Antígenos CD20/genética , Feminino , Genótipo , Humanos , Imunoglobulina G/imunologia , Linfoma não Hodgkin/genética , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético , Rituximab , Resultado do TratamentoRESUMO
Waldenström's macroglobulinemia is a B-cell disorder characterized by bone marrow infiltration with lymphoplasmacytic cells and demonstration of an immunoglobulin M monoclonal gammopathy. Despite advances in therapy, Waldenström's macroglobulinemia remains incurable. As such, novel therapeutic agents are needed for the treatment of Waldenström's macroglobulinemia. In ongoing efforts, we and others have sought to exploit advances made in the understanding of the biology of Waldenström's macroglobulinemia so as to better target therapeutics for this malignancy. Importantly, as part of these efforts, we have prioritized the development of stem cell-sparing drugs because autologous stem cell transplantation remains a viable salvage option in Waldenström's macroglobulinemia. These efforts have led to the development of several novel agents for treating Waldenström's macroglobulinemia, including bortezomib; monoclonal antibodies and/or blocking protein targeting CD40, CD52, or CD70, a proliferation-inducing ligand and B-lymphocyte stimulator; the immunomodulator thalidomide as an enhancer of rituximab activity, as well as agents interfering with stem cell factor, phosphatidylinositol 3-kinase/Akt, phosphodiesterase, cholesterol, and protein kinase C beta signaling. This report provides an update on biologic studies and clinical efforts for the development of these novel agents in the treatment of Waldenström's macroglobulinemia.
Assuntos
Antineoplásicos/uso terapêutico , Fatores Imunológicos/uso terapêutico , Inibidores de Proteases/uso terapêutico , Macroglobulinemia de Waldenstrom/tratamento farmacológico , Animais , HumanosRESUMO
BACKGROUND: Alemtuzumab is a monoclonal antibody used in the treatment of CD52-expressing B-cell malignancies, including Waldenstrom's macroglobulinemia (WM). Recent studies demonstrate high levels of alemtuzumab activity in relapsed/refractory disease. One potential target of alemtuzumab is bone marrow mast cells (BMMCs), which provide growth and survival signaling for WM lymphoplasmacytic cells. PATIENTS AND METHODS: We therefore examined BMMCs (FceRI+, CD117+) from WM and other mast cell (MC) disorders for expression of CD52. RESULTS: We identified cell surface antigen expression by multicolor flow cytometric analysis and found CD52 expressed on human mast-derived cell line-1 (HMC-1) and LAD2 MC lines, on BMMC from 13 of 15 patients with WM, and on BMMCs from 4 of 4 patients with systemic mastocytosis (SM). None of 4 healthy donors expressed CD52. Reverse-transcriptase polymerase chain reaction analysis confirmed CD52 expression in the HMC-1 and LAD2 MC lines, in BMMCs from 14 of 15 patients with WM, and 3 of 3 patients with SM. CD52 transcripts were also detected in BMMCs from 6 of 6 healthy donors, despite the absence of CD52 cell surface expression. Importantly, we observed high levels of alemtuzumab-mediated, antibody-dependent, cell-mediated cytotoxicity against LAD2 MCs and BMMCs from patients with WM and SM. CONCLUSION: These studies demonstrate that CD52 is widely expressed on human MCs and WM bone marrow lymphoplasmacytic cells and provide the preclinical rationale for the use of alemtuzumab in the treatment of WM and possibly other MC-related disorders.
Assuntos
Anticorpos Monoclonais/uso terapêutico , Anticorpos Antineoplásicos/uso terapêutico , Antígenos CD/imunologia , Antígenos de Neoplasias/imunologia , Células da Medula Óssea/imunologia , Glicoproteínas/imunologia , Mastócitos/imunologia , Mastocitose/tratamento farmacológico , Macroglobulinemia de Waldenstrom/tratamento farmacológico , Alemtuzumab , Anticorpos Monoclonais Humanizados , Antígenos CD/genética , Antígenos de Neoplasias/genética , Apoptose/efeitos dos fármacos , Células da Medula Óssea/patologia , Antígeno CD52 , Glicoproteínas/genética , Humanos , Mastócitos/efeitos dos fármacos , Mastócitos/patologia , Mastocitose/imunologia , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Macroglobulinemia de Waldenstrom/imunologiaRESUMO
IL-17 is the founding member of a family of cytokines and receptors with unique structures and signaling properties. IL-17 is the signature cytokine of Th17 cells, a relatively new T cell population that promotes inflammation in settings of infection and autoimmunity. Despite advances in understanding Th17 cells, mechanisms of IL-17-mediated signal transduction are less well defined. IL-17 signaling requires contributions from two receptor subunits, IL-17RA and IL-17RC. Mutants of IL-17RC lacking the cytoplasmic domain are nonfunctional, indicating that IL-17RC provides essential but poorly understood signaling contributions to IL-17-mediated signaling. To better understand the role of IL-17RC in signaling, we performed a yeast 2-hybrid screen to identify novel proteins associated with the IL-17RC cytoplasmic tail. One of the most frequent candidates was the anaphase promoting complex protein 7 (APC7 or AnapC7), which interacted with both IL-17RC and IL-17RA. Knockdown of AnapC7 by siRNA silencing exerted no detectable impact on IL-17 signaling. However, AnapC5, which associates with AnapC7, was also able to bind IL-17RA and IL-17RC. Moreover, AnapC5 silencing enhanced IL-17-induced gene expression, suggesting an inhibitory activity. Strikingly, AnapC5 also associated with A20 (TNFAIP3), a recently-identified negative feedback regulator of IL-17 signal transduction. IL-17 signaling was not impacted by knockdown of Itch or TAXBP1, scaffolding proteins that mediate A20 inhibition in the TNFα and IL-1 signaling pathways. These data suggest a model in which AnapC5, rather than TAX1BP1 and Itch, is a novel adaptor and negative regulator of IL-17 signaling pathways.
Assuntos
Subunidade Apc5 do Ciclossomo-Complexo Promotor de Anáfase/metabolismo , Proteínas de Ligação a DNA/metabolismo , Interleucina-17/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Transdução de Sinais , Ubiquitina-Proteína Ligases/metabolismo , Motivos de Aminoácidos , Animais , Subunidade Apc7 do Ciclossomo-Complexo Promotor de Anáfase/metabolismo , Proteínas de Transporte/metabolismo , Linhagem Celular , Fator D do Complemento/metabolismo , Cisteína Endopeptidases , Camundongos , Modelos Biológicos , Ligação Proteica , Mapeamento de Interação de Proteínas , Subunidades Proteicas/metabolismo , Receptores de Interleucina-17/química , Receptores de Interleucina-17/metabolismo , Proteína 3 Induzida por Fator de Necrose Tumoral alfa , Técnicas do Sistema de Duplo-Híbrido , Proteínas ras/metabolismoAssuntos
Melanoma/terapia , Terapia de Alvo Molecular/métodos , Terapia de Alvo Molecular/tendências , Neoplasias Cutâneas/terapia , Pesquisa Translacional Biomédica/métodos , Pesquisa Translacional Biomédica/tendências , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Humanos , MAP Quinase Quinase Quinases/antagonistas & inibidores , Melanoma/fisiopatologia , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , PTEN Fosfo-Hidrolase/antagonistas & inibidores , Inibidores de Fosfoinositídeo-3 Quinase , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Neoplasias Cutâneas/fisiopatologiaRESUMO
The interleukin (IL)-17 cytokine family members IL-17A and IL-17F mediate inflammatory activities via the IL-17 receptor (IL-17R) complex, comprised of the IL-17RA and IL-17RC subunits. Proper regulation of the IL-17 signaling axis results in effective host defense against extracellular pathogens, while aberrant signaling can drive autoimmune pathology. Elucidating the molecular mechanisms underlying IL-17 signal transduction can yield an enhanced understanding of inflammatory immune processes and also create an avenue for therapeutic intervention in the treatment of IL-17-dependent diseases. To date, the fundamental signaling mechanisms used by the IL-17R complex are still incompletely defined. While current structure-function studies have primarily focused on the IL-17RA subunit, recent research indicates that the IL-17RC subunit plays a key role in modulating IL-17 responses. This review will examine what is known regarding IL-17RC function and provide a framework for future work on this subunit and its impact on human health.