RESUMO
Sphingosine-1-phosphate (S1P) receptors are critical for lymphocyte egress from secondary lymphoid organs, and S1P receptor modulators suppress lymphocyte circulation. However, the role of S1P receptors on monocytes is less clear. To elucidate this, we systematically evaluated monocytes in rats and mice, both in naive and inflammatory conditions, with S1P receptor modulators FTY720 and BAF312. We demonstrate that S1P receptor modulators reduce circulating monocytes in a similar time course as lymphocytes. Furthermore, total monocyte numbers were increased in the spleen and bone marrow, suggesting that S1P receptor modulation restricts egress from hematopoietic organs. Monocytes treated ex vivo with FTY720 had reduced CD40 expression and TNF-α production, suggesting a direct effect on monocyte activation. Similar reductions in protein expression and cytokine production were also found in vivo. Suppression of experimental autoimmune encephalomyelitis in mice and rats by FTY720 correlated with reduced numbers of lymphocytes and monocytes. These effects on monocytes were independent of S1P3, as treatment with BAF312, a S1P1,4,5 modulator, led to similar results. These data reveal a novel role for S1P receptors on monocytes and offer additional insights on the mechanism of action of S1P receptor modulators in disease.
Assuntos
Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Propilenoglicóis/farmacologia , Receptores de Lisoesfingolipídeo/metabolismo , Esfingosina/análogos & derivados , Animais , Medula Óssea/efeitos dos fármacos , Medula Óssea/metabolismo , Movimento Celular/imunologia , Citocinas/biossíntese , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/metabolismo , Feminino , Cloridrato de Fingolimode , Células Matadoras Naturais/metabolismo , Contagem de Leucócitos , Camundongos , Monócitos/imunologia , Neutrófilos/metabolismo , Ratos , Esfingosina/farmacologia , Baço/efeitos dos fármacos , Baço/metabolismoRESUMO
Hidradenitis suppurativa (HS) is a chronic inflammatory disease manifesting as painful dermal nodules, abscesses, and tunnels. Activation of the IL-1R/toll-like receptor pathway is strongly implicated in the pathogenesis of HS; thus, the role of a key signaling node, IRAK4, was investigated in a noninterventional study (NCT04440410) that enrolled 30 patients with HS. IRAK4 expression was evaluated in blood and lesional, perilesional, and nonlesional skin biopsies. PBMCs expressed IRAK4, with significantly higher levels in monocytes (P ≤ .0001). Ex vivo treatment of PBMCs with KT-474, a targeted degrader of IRAK4, robustly decreased IRAK4 in all immune cell types from healthy volunteers and patients with HS. Ex vivo treatment of toll-like receptor-stimulated healthy donor monocytes with KT-474 decreased IRAK4 protein levels and inhibited inflammatory cytokine production. In HS skin samples, IRAK4 protein levels were significantly higher in lesional than in nonlesional tissue (P ≤ .0001), and IRAK4-positive immune infiltrate increased with greater disease severity. Multiple inflammatory mediators were upregulated in HS lesional skin, correlating with IRAK4 overexpression. These data confirm the significance of the IL-1R/toll-like receptor pathway in the pathogenesis of HS and provide support for ongoing clinical studies evaluating KT-474 in the treatment of HS.
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Preclinical human inflammatory bowel disease (IBD) mechanisms is one of 5 focus areas of the Challenges in IBD Research 2024 document, which also includes environmental triggers, novel technologies, precision medicine, and pragmatic clinical research. Herein, we provide a comprehensive overview of current gaps in inflammatory bowel diseases research that relate to preclinical research and deliver actionable approaches to address them with a focus on how these gaps can lead to advancements in IBD interception, remission, and restoration. The document is the result of multidisciplinary input from scientists, clinicians, patients, and funders and represents a valuable resource for patient-centric research prioritization. This preclinical human IBD mechanisms section identifies major research gaps whose investigation will elucidate pathways and mechanisms that can be targeted to address unmet medical needs in IBD. Research gaps were identified in the following areas: genetics, risk alleles, and epigenetics; the microbiome; cell states and interactions; barrier function; IBD complications (specifically fibrosis and stricturing); and extraintestinal manifestations. To address these gaps, we share specific opportunities for investigation for basic and translational scientists and identify priority actions.
To address the unmet medical needs of patients with inflammatory bowel diseases (IBD) and move toward cures, preclinical human-relevant research must center on mechanistic questions pertinent to patients with IBD in the 3 areas of disease interception, remission, and restoration.
Assuntos
Doenças Inflamatórias Intestinais , Humanos , Doenças Inflamatórias Intestinais/microbiologia , Animais , Microbioma Gastrointestinal , Pesquisa Biomédica , Medicina de Precisão/métodosRESUMO
Interleukin-1 receptor associated kinase 4 (IRAK4) is an essential mediator of the IL-1R and TLR signaling pathways, both of which have been implicated in multiple autoimmune conditions. Hence, blocking the activity of IRAK4 represents an attractive approach for the treatment of autoimmune diseases. The activity of this serine/threonine kinase is dependent on its kinase and scaffolding activities; thus, degradation represents a potentially superior approach to inhibition. Herein, we detail the exploration of structure-activity relationships that ultimately led to the identification of KT-474, a potent, selective, and orally bioavailable heterobifunctional IRAK4 degrader. This represents the first heterobifunctional degrader evaluated in a nononcology indication and dosed to healthy human volunteers. This molecule successfully completed phase I studies in healthy adult volunteers and patients with atopic dermatitis or hidradenitis suppurativa. Phase II clinical trials in both of these indications have been initiated.
RESUMO
Developing therapies for the activated B-cell like (ABC) subtype of diffuse large B-cell lymphomas (DLBCL) remains an area of unmet medical need. A subset of ABC DLBCL tumors is driven by activating mutations in myeloid differentiation primary response protein 88 (MYD88), which lead to constitutive activation of interleukin-1 receptor associated kinase 4 (IRAK4) and cellular proliferation. IRAK4 signaling is driven by its catalytic and scaffolding functions, necessitating complete removal of this protein and its escape mechanisms for complete therapeutic suppression. Herein, we describe the identification and characterization of a dual-functioning molecule, KT-413 and show it efficiently degrades IRAK4 and the transcription factors Ikaros and Aiolos. KT-413 achieves concurrent degradation of these proteins by functioning as both a heterobifunctional degrader and a molecular glue. Based on the demonstrated activity and safety of KT-413 in preclinical studies, a phase 1 clinical trial in B-cell lymphomas, including MYD88 mutant ABC DLBCL, is currently underway.
Assuntos
Quinases Associadas a Receptores de Interleucina-1 , Linfoma Difuso de Grandes Células B , Mutação , Fator 88 de Diferenciação Mieloide , Quinases Associadas a Receptores de Interleucina-1/metabolismo , Quinases Associadas a Receptores de Interleucina-1/antagonistas & inibidores , Fator 88 de Diferenciação Mieloide/metabolismo , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/genética , Linfoma Difuso de Grandes Células B/metabolismo , Linfoma Difuso de Grandes Células B/patologia , Humanos , Animais , Linhagem Celular Tumoral , Descoberta de Drogas , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/uso terapêutico , Camundongos , Imidazóis/química , Imidazóis/farmacologia , Imidazóis/metabolismo , Proteólise/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
Toll-like receptor-driven and interleukin-1 (IL-1) receptor-driven inflammation mediated by IL-1 receptor-associated kinase 4 (IRAK4) is involved in the pathophysiology of hidradenitis suppurativa (HS) and atopic dermatitis (AD). KT-474 (SAR444656), an IRAK4 degrader, was studied in a randomized, double-blind, placebo-controlled phase 1 trial where the primary objective was safety and tolerability. Secondary objectives included pharmacokinetics, pharmacodynamics and clinical activity in patients with moderate to severe HS and in patients with moderate to severe AD. KT-474 was administered as a single dose and then daily for 14 d in 105 healthy volunteers (HVs), followed by dosing for 28 d in an open-label cohort of 21 patients. Degradation of IRAK4 was observed in HV blood, with mean reductions after a single dose of ≥93% at 600-1,600 mg and after 14 daily doses of ≥95% at 50-200 mg. In patients, similar IRAK4 degradation was achieved in blood, and IRAK4 was normalized in skin lesions where it was overexpressed relative to HVs. Reduction of disease-relevant inflammatory biomarkers was demonstrated in the blood and skin of patients with HS and patients with AD and was associated with improvement in skin lesions and symptoms. There were no drug-related infections. These results, from what, to our knowledge, is the first published clinical trial using a heterobifunctional degrader, provide initial proof of concept for KT-474 in HS and AD to be further confirmed in larger trials. ClinicalTrials.gov identifier: NCT04772885 .
Assuntos
Dermatite Atópica , Hidradenite Supurativa , Humanos , Hidradenite Supurativa/tratamento farmacológico , Dermatite Atópica/tratamento farmacológico , Quinases Associadas a Receptores de Interleucina-1 , Resultado do Tratamento , Pele/patologia , Método Duplo-Cego , Índice de Gravidade de DoençaRESUMO
OBJECTIVE: Clinical studies indicate that anti-CD20 B-cell depletion may be an effective multiple sclerosis (MS) therapy. We investigated mechanisms of anti-CD20-mediated immune modulation using 2 paradigms of experimental autoimmune encephalomyelitis (EAE). METHODS: Murine EAE was induced by recombinant myelin oligodendrocyte glycoprotein (rMOG), a model in which B cells are considered to contribute pathogenically, or MOG peptide (p)35-55, which does not require B cells. RESULTS: In EAE induced by rMOG, B cells became activated and, when serving as antigen-presenting cells (APCs), promoted differentiation of proinflammatory MOG-specific Th1 and Th17 cells. B-cell depletion prevented or reversed established rMOG-induced EAE, which was associated with less central nervous system (CNS) inflammation, elimination of meningeal B cells, and reduction of MOG-specific Th1 and Th17 cells. In contrast, in MOG p35-55-induced EAE, B cells did not become activated or efficiently polarize proinflammatory MOG-specific T cells, similar to naive B cells. In this setting, anti-CD20 treatment exacerbated EAE, and did not impede development of Th1 or Th17 cells. Irrespective of the EAE model used, B-cell depletion reduced the frequency of CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg), and increased the proinflammatory polarizing capacity of remaining myeloid APCs. INTERPRETATION: Our study highlights distinct roles for B cells in CNS autoimmunity. Clinical benefit from anti-CD20 treatment may relate to inhibition of proinflammatory B cell APC function. In certain clinical settings, however, elimination of unactivated B cells, which participate in regulation of T cells and other APC, may be undesirable. Differences in immune responses to MOG protein and peptide may be important considerations when choosing an EAE model for testing novel B cell-targeting agents for MS.
Assuntos
Anticorpos/uso terapêutico , Antígenos CD20/imunologia , Encefalomielite Autoimune Experimental/tratamento farmacológico , Encefalomielite Autoimune Experimental/fisiopatologia , Ativação Linfocitária/imunologia , Animais , Antígenos CD20/genética , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Citocinas/metabolismo , Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/imunologia , Feminino , Citometria de Fluxo/métodos , Fatores de Transcrição Forkhead/metabolismo , Glicoproteínas/efeitos adversos , Humanos , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Ativação Linfocitária/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Glicoproteína Mielina-Oligodendrócito , Fragmentos de Peptídeos/efeitos adversos , Estatísticas não Paramétricas , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologiaRESUMO
Transient transfection of mammalian cells in suspension culture has recently emerged as a very useful method for production of research-scale quantities of recombinant proteins. The most commonly used cell lines for this purpose are suspension-adapted HEK and CHO cells. We report here that the plasma exposure in mice of an IL-23R extracellular domain Fc fusion protein (IL23R-Fc) differed dramatically depending on whether the protein was prepared by transient transfection of HEK or CHO cells. Specifically, IL23R-Fc expressed using CHO cells had about 30-fold higher in vivo plasma exposure compared to the HEK-expressed protein. In contrast to their differing plasma exposures, the HEK- and CHO-expressed proteins had equivalent in vitro biological activity. Characterization of the CHO- and HEK-expressed IL23R-Fc proteins indicated that the differences in in vivo plasma exposure between them are due to differential glycosylation.
Assuntos
Espaço Extracelular/metabolismo , Receptores Fc/metabolismo , Receptores de Interleucina/sangue , Receptores de Interleucina/química , Proteínas Recombinantes de Fusão/metabolismo , Transfecção/métodos , Sequência de Aminoácidos , Animais , Células CHO , Cricetinae , Cricetulus , Eletroforese em Gel de Poliacrilamida , Glicosilação , Humanos , Focalização Isoelétrica , Lectinas/metabolismo , Camundongos , Dados de Sequência Molecular , Estrutura Terciária de Proteína , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/farmacocinéticaRESUMO
T cells are classically recognized as distinct subsets that express αß or γδ TCRs. We identify a novel population of T cells that coexpress αß and γδ TCRs in mice and humans. These hybrid αß-γδ T cells arose in the murine fetal thymus by day 16 of ontogeny, underwent αß TCR-mediated positive selection into CD4+ or CD8+ thymocytes, and constituted up to 10% of TCRδ+ cells in lymphoid organs. They expressed high levels of IL-1R1 and IL-23R and secreted IFN-γ, IL-17, and GM-CSF in response to canonically restricted peptide antigens or stimulation with IL-1ß and IL-23. Hybrid αß-γδ T cells were transcriptomically distinct from conventional γδ T cells and displayed a hyperinflammatory phenotype enriched for chemokine receptors and homing molecules that facilitate migration to sites of inflammation. These proinflammatory T cells promoted bacterial clearance after infection with Staphylococcus aureus and, by licensing encephalitogenic Th17 cells, played a key role in the development of autoimmune disease in the central nervous system.
Assuntos
Inflamação/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Linfócitos T/imunologia , Animais , Biomarcadores/metabolismo , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/patologia , Humanos , Inflamação/patologia , Ativação Linfocitária/imunologia , Camundongos Endogâmicos C57BL , Fenótipo , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T gama-delta/genética , Infecções Estafilocócicas/imunologia , Staphylococcus aureus/fisiologia , Transcrição Gênica , Transcriptoma/genéticaRESUMO
Interleukin-17A (IL17A) plays a critical role in the development of numerous autoimmune diseases, including psoriasis. The clinical success of IL17A neutralizing biologics in psoriasis has underlined its importance as a drug discovery target. While many studies have focused on the differentiation and trafficking of IL17A producing T-helper 17 cells, less is known about IL17A-initiated signaling events in stromal and parenchymal cells leading to psoriatic phenotypes. We sought to discover signaling nodes downstream of IL17A contributing to disease pathogenesis. Using IL17A and tumor necrosis factor α (TNF) to stimulate primary human epidermal keratinocytes, we employed two different phenotypic screening approaches. First, a library of â¼22000 annotated compounds was screened for reduced secretion of the pro-inflammatory chemokine IL8. Second, a library of 729 kinases was screened in a pooled format by utilizing CRISPR-Cas9 and monitoring IL8 intracellular staining. The highest-ranking novel hits identified in both screens were the bromodomain and extra-terminal domain (BET) family proteins and bromodomain-containing protein 2 (BRD2), respectively. Comparison of BRD2, BRD3, and BRD4 silencing with siRNA and CRISPR confirmed that BRD2 was responsible for mediating IL8 production. Pan-BRD inhibitors and BRD2 knockout also reduced IL17A/TNF-mediated CXC motif chemokines 1/2/6 (CXCL1/2/6) and granulocyte colony stimulating factor (G-CSF) production. In RNA-Seq analysis, 438 IL17A/TNF dependent genes were reduced in BRD2-deficient primary keratinocytes. KEGG pathway analysis of these genes showed enrichment in TNF signaling and rheumatoid arthritis relevant genes. Moreover, a number of genes important for keratinocyte homeostasis and cornification were dysregulated in BRD2-deficient keratinocytes. In IL17A/TNF/IL22 stimulated three-dimensional organotypic raft cultures, pan-BRD inhibition reduced inflammatory factor production but elicited aberrant cornification, consistent with RNA-Seq analysis. These studies highlight a novel role for BRDs and BRD2 in particular in IL17A-mediated inflammatory signaling.
Assuntos
Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Inflamação/metabolismo , Interleucina-17/metabolismo , Queratinócitos/metabolismo , Transdução de Sinais , Bibliotecas de Moléculas Pequenas/metabolismo , Fatores de Transcrição/metabolismo , Diferenciação Celular , Células Cultivadas , Técnicas de Silenciamento de Genes , Homeostase , Humanos , Queratinócitos/citologia , RNA Interferente Pequeno/genética , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
OBJECTIVE: For a successful immune response, migration of lymphocytes to lymphoid organs and other tissues is a key step, as the initial recognition of foreign antigens and activation of lymphocytes takes place in these organs. CD62L is a homing receptor that mediates entry of naïve T cells to peripheral lymph nodes. Maybe the preventing of T cell homing will change the immune response against allogeneic tissue and suppress rejection. METHODS: We treated different mouse strains with pertussis toxin to manipulate T cell homing and measured the rejection of allografts in terms of allogeneic tumor cells. We transferred pertussis toxin treated or nontreated transgenic T cells into BALB/c wild type mice. The transgenic T cells could be followed ex vivo by specific antibodies. Cytokine production from purified (1x10(5)/ml) T cells after different stimulations in vitro and expression of surface markers on T cells following pertussis toxin treatment by FACS analysis were performed. RESULTS: Pertussis toxin-treated C57BL/6 mice with the MHC class I molecule H-2K(b) could not reject allogeneic tumor cells R1.1, which expressed the MHC class I molecule H-2K(k) and were killed by these cells. This allograft survival could be demonstrated for various allogeneic cells in different mouse strains with different MHC class I expression and emphasizes the general mechanism in these studies. In vivo CD62L expression on T cells was down-regulated by pertussis toxin in normal mice and transgenic mice that produce only one specific T cell, and after the pertussis toxin treatment the mice showed 4-5 times larger spleens compared to untreated mice. In transfer experiments, we demonstrated that CD62L low transgenic T cells could not home to lymph nodes. Furthermore, spleen cells from pertussis toxin-treated mice produced high amounts of the Th-2 cytokine interleukin 4 after stimulation in primary culture. CONCLUSIONS: Our data suggest that the inhibition of T cell homing changes the immune response. Prevention of homing of T cells in combination with the induction of a Th-2 response is a mechanism to prevent specific acute rejection of allogeneic tissue.
Assuntos
Regulação para Baixo/imunologia , Rejeição de Enxerto/prevenção & controle , Selectina L/metabolismo , Células Th2/imunologia , Doença Aguda , Transferência Adotiva , Animais , Movimento Celular/imunologia , Proliferação de Células , Células Cultivadas , Citocinas/biossíntese , Feminino , Rejeição de Enxerto/imunologia , Tolerância Imunológica , Selectina L/imunologia , Ativação Linfocitária/imunologia , Camundongos , Camundongos Endogâmicos , Transplante de Neoplasias , Toxina Pertussis/imunologia , Células Tumorais CultivadasRESUMO
While neuromyelitis optica (NMO) immunoglobulin (Ig) G is considered the hallmark serologic marker of NMO, its association is not absolute, as NMO IgG is not detected in approximately one-fourth of the patients diagnosed with NMO spectrum disorder (NMOSD). Thus, the recent discovery that antibodies to myelin oligodendrocyte glycoprotein (MOG) are detected in some NMO IgG-seronegative patients manifesting clinical and neuroimaging signs of NMO or NMOSD has created tremendous excitement. However, it may be premature to classify this subgroup as NMOSD. NMO is considered an autoimmune astrocytopathy, and aquaporin-4 (AQP4), expressed on astrocytes, is recognized as the target autoantigen of NMO IgG. As its name denotes, MOG is produced by oligodendrocytes, CNS myelin-producing cells, and MOG is well-recognized as one of the candidate autoantigens in multiple sclerosis (MS) and acute disseminated encephalomyelitis (ADEM). Thus, is it possible that the clinical NMOSD-like phenotype associated with MOG-specific antibodies represents a variant of opticospinal MS or ADEM but not AQP4 autoimmunity or NMOSD? Whether this MOG-Ig positive AQP4-seronegative phenotype should be classified as NMOSD, opticospinal MS, or a unique entity is not simply a theoretical question but rather has practical implications for patients, their physicians, insurance carriers, and clinical investigators conducting NMO treatment trials.
RESUMO
Autoimmune disorders represent inappropriate immune responses directed at self-tissue. Because CD4+ T cells are important mediators in the pathogenesis of autoimmune disease, they are ideal candidates for cell-based gene therapy. Using retrovirally-transduced cells and luciferase bioluminescence, we have demonstrated that primary T cells and hybridomas, rapidly and preferentially home to the sites of inflammation in organ-specific autoimmune disease. These cells, transduced with retroviral vectors to drive expression of various 'regulatory proteins', such as IL-4, IL-10 and IL-12p40, deliver these immunoregulatory proteins to the inflamed lesions, providing therapy for experimental models of autoimmune disease such as EAE, CIA and NOD mice. This technique was originally developed in our lab in the murine model of multiple sclerosis, EAE, where T cell hybridomas reactive with myelin basic protein (MBP) were transduced to express and used to deliver the modulatory cytokine, IL-4. Recently we have observed that the cytokine receptor antagonist, IL-12p40 transduced anti-myelin basic protein (MBP) TCR-transgenic T cells (but not CII-reactive T cells) were effective in preventing EAE whereas the CII-reactive, but not MBP-reactive T cells, transduced to express IL-12p40, would treat CIA.
Assuntos
Doenças Autoimunes/terapia , Terapia Genética/métodos , Transferência Adotiva , Animais , Artrite Experimental/imunologia , Artrite Experimental/terapia , Doenças Autoimunes/imunologia , Células Dendríticas/imunologia , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/terapia , Vetores Genéticos , Medições Luminescentes , Camundongos , Retroviridae/genéticaRESUMO
Autoimmune disorders represent inappropriate immune responses directed at self-tissue. Antigen-specific CD4+ T cells and antigen-presenting dendritic cells (DCs) are important mediators in the pathogenesis of auto-immune disease and thus are ideal candidates for adoptive cellular gene therapy, an ex vivo approach to therapeutic gene transfer. Using retrovirally transduced cells and luciferase bioluminescence, we have demonstrated that primary T cells, T cell hybridomas, and DCs rapidly and preferentially home to the sites of inflammation in animal models of multiple sclerosis, arthritis, and diabetes. These cells, transduced with retroviral vectors to drive expression of various "regulatory proteins" such as IL-4, IL-10, IL-12p40, and anti-TNF scFv, deliver these immunoregulatory proteins to the inflamed lesions, providing therapy for experimental autoimmune encephalitis (EAE), collagen-induced arthritis (CIA), and nonobese diabetic mice (NOD).
Assuntos
Transferência Adotiva , Doenças Autoimunes/terapia , Terapia Genética , Animais , Células Dendríticas/metabolismo , Vetores Genéticos/genética , Humanos , Medições Luminescentes , Retroviridae/genética , Linfócitos T/metabolismoRESUMO
Sphingosine-1-phosphate (S1P) is a bioactive metabolite with pleiotropic effects on multiple cellular processes in health and disease. Responses elicited by S1P are a result of binding to five specific G-protein-coupled receptors. We have developed multiple assays to systematically study the downstream signaling of these receptors, including early events such as direct receptor activation (GTPγS) as well as more distal events such as S1P1 receptor degradation. Employing such assays, we have characterized and compared multiple S1P1 agonists that are in clinical development including FTY720, BAF312, CS-0777, and other molecules from the S1P1 patent literature. Our parallel assessment has allowed us to compare their potency against S1P1, their selectivity against the four other S1P receptors, as well as species cross-reactivity. We note that all of the compounds studied signal in an identical manner through S1P1, leading to receptor degradation.
Assuntos
Regulação para Baixo/efeitos dos fármacos , Receptores de Lisoesfingolipídeo/agonistas , Receptores de Lisoesfingolipídeo/antagonistas & inibidores , Animais , Células CHO , Cálcio/metabolismo , Linhagem Celular , Cricetulus , AMP Cíclico/metabolismo , Relação Dose-Resposta a Droga , Descoberta de Drogas , Humanos , Camundongos , Organofosfatos/farmacologia , Proteólise/efeitos dos fármacos , Ratos , Receptores de Lisoesfingolipídeo/metabolismo , Esfingosina/análogos & derivados , Esfingosina/farmacologiaRESUMO
OBJECTIVE: Recently, we reported that the 218 amino acid murine full-length myelin oligodendrocyte glycoprotein (MOG) contains novel T-cell epitopes p119-132, p181-195, and p186-200, located within its transmembrane and cytoplasmic domains, and that p119-132 is its immunodominant encephalitogenic T-cell epitope in mice. Here, we investigated whether the corresponding human MOG sequences contain T-cell epitopes in patients with multiple sclerosis (MS) and healthy controls (HC). METHODS: Peripheral blood T cells from patients with MS and HC were examined for proliferation to MOG p119-130, p181-195, p186-200, and p35-55 by fluorescence-activated cell sorting analysis using carboxylfluorescein diacetate succinimidyl ester dilution assay. Intracellular production of proinflammatory cytokines was analyzed by flow cytometry. RESULTS: MOG p119-130, p181-195, and p186-200 elicited significantly greater T-cell responses than p35-55 in patients with MS. T cells from patients with MS proliferated significantly more strongly to MOG p119-130 and p186-200 than did T cells from HC. Further, MOG p119-130-specific T cells exhibited Th17 polarization, suggesting this T-cell epitope may be relevant to MS pathogenesis. CONCLUSIONS: Transmembrane and cytoplasmic MOG domains contain potent T-cell epitopes in MS. Recognition of these determinants is important when evaluating T-cell responses to MOG in MS and may have implications for development of myelin antigen-based therapeutics.
RESUMO
OBJECTIVE: Studies evaluating T-cell recognition of myelin oligodendrocyte glycoprotein (MOG) in multiple sclerosis (MS) and its model, experimental autoimmune encephalomyelitis (EAE), have focused mostly on its 117 amino acid (aa) extracellular domain, especially peptide (p) 35-55. We characterized T-cell responses to the entire 218 aa MOG sequence, including its transmembrane and cytoplasmic domains. METHODS: T-cell recognition in mice was examined using overlapping peptides and intact full-length mouse MOG. EAE was evaluated by peptide immunization and by adoptive transfer of MOG epitope-specific T cells. Frequency of epitope-specific T cells was examined by ELISPOT. RESULTS: Three T-cell determinants of MOG were discovered in its transmembrane and cytoplasmic domains, p119-132, p181-195, and p186-200. Transmembrane MOG p119-132 induced clinical EAE, CNS inflammation, and demyelination as potently as p35-55 in C57BL/6 mice and other H-2(b) strains. p119-128 contained its minimal encephalitogenic epitope. p119-132 did not cause disease in EAE-susceptible non-H-2(b) strains, including Biozzi, NOD, and PL/J. MOG p119-132-specific T cells produced Th1 and Th17 cytokines and transferred EAE to wild-type recipient mice. After immunization with full-length MOG, a significantly higher frequency of MOG-reactive T cells responded to p119-132 than to p35-55, demonstrating that p119-132 is an immunodominant encephalitogenic epitope. MOG p181-195 did not cause EAE, and MOG p181-195-specific T cells could not transfer EAE into wild-type or highly susceptible T- and B-cell-deficient mice. CONCLUSIONS: Transmembrane and cytoplasmic domains of MOG contain immunodominant T-cell epitopes in EAE. A CNS autoantigen can also contain nonpathogenic stimulatory T-cell epitopes. Recognition that a myelin antigen contains multiple encephalitogenic and nonencephalitogenic determinants may have implications for therapeutic development in MS.
RESUMO
Whether B cells serve as antigen-presenting cells (APCs) for activation of pathogenic T cells in the multiple sclerosis model experimental autoimmune encephalomyelitis (EAE) is unclear. To evaluate their role as APCs, we engineered mice selectively deficient in MHC II on B cells (B-MHC II(-/-)), and to distinguish this function from antibody production, we created transgenic (Tg) mice that express the myelin oligodendrocyte glycoprotein (MOG)-specific B cell receptor (BCR; IgH(MOG-mem)) but cannot secrete antibodies. B-MHC II(-/-) mice were resistant to EAE induced by recombinant human MOG (rhMOG), a T cell- and B cell-dependent autoantigen, and exhibited diminished Th1 and Th17 responses, suggesting a role for B cell APC function. In comparison, selective B cell IL-6 deficiency reduced EAE susceptibility and Th17 responses alone. Administration of MOG-specific antibodies only partially restored EAE susceptibility in B-MHC II(-/-) mice. In the absence of antibodies, IgH(MOG-mem) mice, but not mice expressing a BCR of irrelevant specificity, were fully susceptible to acute rhMOG-induced EAE, also demonstrating the importance of BCR specificity. Spontaneous opticospinal EAE and meningeal follicle-like structures were observed in IgH(MOG-mem) mice crossed with MOG-specific TCR Tg mice. Thus, B cells provide a critical cellular function in pathogenesis of central nervous system autoimmunity independent of their humoral involvement, findings which may be relevant to B cell-targeted therapies.
Assuntos
Células Apresentadoras de Antígenos/imunologia , Linfócitos B/imunologia , Sistema Nervoso Central/imunologia , Genes MHC da Classe II , Bainha de Mielina/imunologia , Animais , Proliferação de Células , Separação Celular , Citocinas/metabolismo , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/imunologia , Citometria de Fluxo , Regulação da Expressão Gênica , Predisposição Genética para Doença , Imunoglobulinas/imunologia , Interleucina-6/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Células Th1/imunologia , Células Th17/imunologiaRESUMO
Multiple sclerosis (MS) is a devastating autoimmune disease that affects more than 1 million people worldwide and severely compromises motor and sensory function through demyelination and axonal loss. This review covers current therapies, lessons learned from failed clinical trials, genetic susceptibility, key cell types involved, animal models, gene expression, and biomarker information. The current first-line therapies for MS include the type I interferons (IFN-I) and glatiramer acetate (GA) but because of their limited effectiveness new therapeutic modalities are required. Tysabri is an anti very late antigen-4 antibody that antagonizes the migration of multiple cell types and appears more efficacious as compared to the IFNs or GA. Tysabri blocks the transmigration of T cells and monocytes, which indicates that blocking multiple cell types may increase the effectiveness of the therapy. However, this therapy may increase the risk of progressive multifocal leukoencephalopathy. The major cell types hypothesized to be pathogenic include T cells and antigen-presenting cells, including B cells. The correlation of the animal model experimental autoimmune encephalomyelitis (EAE) of MS and its predictive value to determine efficacy in the clinic appears limited. However, all current therapies do demonstrate efficacy in EAE models. There are also examples of mechanisms that have worked in EAE but have failed in the clinic, such as the TNFα antagonists and anti-p40 (a subunit of IL-12 and IL-23). The MS field would benefit if clinical biomarkers were available to monitor clinical efficacy. The etiology of MS remains elusive but additional understanding of mechanisms involved in the pathogenesis of MS may guide us to more effective treatment and management of this autoimmune disease.
Assuntos
Encefalomielite Autoimune Experimental/imunologia , Esclerose Múltipla/imunologia , Esclerose Múltipla/terapia , Animais , Ensaios Clínicos como Assunto , Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/terapia , Predisposição Genética para Doença , Humanos , Imunossupressores/farmacologia , Imunoterapia/métodos , Esclerose Múltipla/genéticaRESUMO
Midkine (MDK) is a heparin-binding growth factor involved in growth, survival, migration, and differentiation of various target cells and dysregulation of MDK signaling is implicated in a variety of inflammatory diseases and cancers. Although MDK has been reported to act on endothelial cells and to have proangiogenic effects, the exact role of MDK in angiogenesis is poorly defined. Here, we report that MDK is actually a modulator of angiogenesis and that it can abrogate the vascular endothelial growth factor A (VEGF-A)-induced proliferation of human microvascular endothelial cells in vitro through the downregulation of proangiogenic cytokines and through the upregulation of the antiangiogenic factor, tissue inhibitor of metalloproteinase 2. Phosphorylation of vascular endothelial growth factor receptor 2 (VEGFR-2) and of downstream signaling molecules, such as phosphatidylinositol-3-kinase and mitogen-activated protein kinases, is also impaired. Moreover, MDK downregulates VEGF-A-induced neovascularization and vascular permeability in vivo. We propose a model in which MDK is a new modulator of the VEGF-A-VEGFR-2 axis.