RESUMEN
AIMS: We examined major protein components of Schwann cells (SCs) and myelin in normal and diseased human peripheral nerves. METHODS: We evaluated distributions of neural cell adhesion molecule (NCAM), P0 protein (P0) and myelin basic protein (MBP) in frozen sections of 98 sural nerves. RESULTS: Non-myelinating SC in normal adults contained NCAM, but not P0 or MBP. With chronic axon loss, SC without associated axons (Büngner band cells) often co-stained for both NCAM and P0. Onion bulb cells also co-stained for both P0 and NCAM. Infants had many SC with MBP but no P0. All myelin sheaths contained P0. Myelin around large, and some intermediate-sized, axons co-stained for both MBP and P0. Myelin on other intermediate-sized axons had P0, but no MBP. Regenerated axons often had sheaths with MBP, P0 and some NCAM. During active axon degeneration, myelin ovoids often co-stained for MBP, P0 and NCAM. Demyelinating neuropathy patterns included SC (NCAM) loss, and myelin with abnormally distributed, or reduced, P0. CONCLUSIONS: Peripheral nerve SC and myelin have varied molecular phenotypes, related to age, axon size and nerve pathology. In normal adult peripheral nerve, myelin has two different patterns of molecular composition. MBP is mostly absent from myelin around a population of intermediate-sized axons, whereas P0 is present in myelin around all axons. Denervated SCs have a molecular signature that differs from normal SC types. With acute denervation, SCs may stain for both NCAM and MBP. Chronically denervated SCs often stain for both NCAM and P0.
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Axones , Vaina de Mielina , Adulto , Humanos , Vaina de Mielina/patología , Axones/patología , Células de Schwann/metabolismo , Células de Schwann/patología , Nervios Periféricos/metabolismo , Moléculas de Adhesión de Célula Nerviosa/metabolismoRESUMEN
OBJECTIVE: The aim of the study is to identify and prioritize early intervention (EI) stakeholders' perspectives of supports and barriers to implementing the Young Children's Participation and Environment Measure (YC-PEM), an electronic patient-reported outcome (e-PRO) tool, for scaling its implementation across multiple local and state EI programs. METHODS: An explanatory sequential (quan > QUAL) mixed-methods study was conducted with EI families (n = 6), service coordinators (n = 9), and program leadership (n = 7). Semi-structured interviews and focus groups were used to share select quantitative pragmatic trial results (e.g., percentages for perceived helpfulness of implementation strategies) and elicit stakeholder perspectives to contextualize these results. Three study staff deductively coded transcripts to constructs in the Consolidated Framework for Implementation Research (CFIR). Data within CFIR constructs were inductively analyzed to generate themes that were rated by national early childhood advisors for their relevance to longer term implementation. RESULTS: All three stakeholder groups (i.e., families, service coordinators, program leadership) identified thematic supports and barriers across multiple constructs within each of four CFIR domains: (1) Six themes for "intervention characteristics," (2) Six themes for "process," (3) three themes for "inner setting," and (4) four themes for "outer setting." For example, all stakeholder groups described the value of the YC-PEM e-PRO in forging connections and eliciting meaningful information about family priorities for efficient service plan development ("intervention characteristics"). Stakeholders prioritized reaching families with diverse linguistic preferences and user navigation needs, further tailoring its interface with automated data capture and exchange processes ("process"); and fostering a positive implementation climate ("inner setting"). Service coordinators and program leadership further articulated the value of YC-PEM e-PRO results for improving EI access ("outer setting"). CONCLUSION: Results demonstrate the YC-PEM e-PRO is an evidence-based intervention that is viable for implementation. Optimizations to its interface are needed before undertaking hybrid type-2 and 3 multisite trials to test these implementation strategies across state and local EI programs with electronic data capture capabilities and diverse levels of organizational readiness and resources for implementation.
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Electrónica , Medición de Resultados Informados por el Paciente , Niño , Humanos , Preescolar , Grupos Focales , Investigación CualitativaRESUMEN
Background: There is increased interest in using artificial intelligence (AI) to provide participation-focused pediatric re/habilitation. Existing reviews on the use of AI in participation-focused pediatric re/habilitation focus on interventions and do not screen articles based on their definition of participation. AI-based assessments may help reduce provider burden and can support operationalization of the construct under investigation. To extend knowledge of the landscape on AI use in participation-focused pediatric re/habilitation, a scoping review on AI-based participation-focused assessments is needed. Objective: To understand how the construct of participation is captured and operationalized in pediatric re/habilitation using AI. Methods: We conducted a scoping review of literature published in Pubmed, PsycInfo, ERIC, CINAHL, IEEE Xplore, ACM Digital Library, ProQuest Dissertation and Theses, ACL Anthology, AAAI Digital Library, and Google Scholar. Documents were screened by 2-3 independent researchers following a systematic procedure and using the following inclusion criteria: (1) focuses on capturing participation using AI; (2) includes data on children and/or youth with a congenital or acquired disability; and (3) published in English. Data from included studies were extracted [e.g., demographics, type(s) of AI used], summarized, and sorted into categories of participation-related constructs. Results: Twenty one out of 3,406 documents were included. Included assessment approaches mainly captured participation through annotated observations (n = 20; 95%), were administered in person (n = 17; 81%), and applied machine learning (n = 20; 95%) and computer vision (n = 13; 62%). None integrated the child or youth perspective and only one included the caregiver perspective. All assessment approaches captured behavioral involvement, and none captured emotional or cognitive involvement or attendance. Additionally, 24% (n = 5) of the assessment approaches captured participation-related constructs like activity competencies and 57% (n = 12) captured aspects not included in contemporary frameworks of participation. Conclusions: Main gaps for future research include lack of: (1) research reporting on common demographic factors and including samples representing the population of children and youth with a congenital or acquired disability; (2) AI-based participation assessment approaches integrating the child or youth perspective; (3) remotely administered AI-based assessment approaches capturing both child or youth attendance and involvement; and (4) AI-based assessment approaches aligning with contemporary definitions of participation.
RESUMEN
During multiple sclerosis (MS), an inflammatory and neurodegenerative disease of the central nervous system (CNS), symptoms, and outcomes are determined by the location of inflammatory lesions. While we and others have shown that T cell cytokines differentially regulate leukocyte entry into perivascular spaces and regional parenchymal localization in murine models of MS, the molecular mechanisms of this latter process are poorly understood. Here, we demonstrate that astrocytes exhibit region-specific responses to T cell cytokines that promote hindbrain versus spinal cord neuroinflammation. Analysis of cytokine receptor expression in human astrocytes showed region-specific responsiveness to Th1 and Th17 inflammatory cytokines. Consistent with this, human and murine astrocytes treated with these cytokines exhibit differential expression of the T cell localizing molecules VCAM-1 and CXCR7 that is both cytokine and CNS region-specific. Using in vivo models of spinal cord versus brain stem trafficking of myelin-specific T cells and astrocyte-specific deletion strategies, we confirmed that Th1 and Th17 cytokines differentially regulate astrocyte expression of VCAM-1 and CXCR7 in these locations. Finally, stereotaxic injection of individual cytokines into the hindbrain or spinal cord revealed region- and cytokine-specific modulation of localizing cue expression by astrocytes. These findings identify a role for inflammatory cytokines in mediating local astrocyte-dependent mechanisms of immune cell trafficking within the CNS during neuroinflammation.
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Astrocitos/metabolismo , Sistema Nervioso Central/metabolismo , Encefalomielitis Autoinmune Experimental/patología , Enfermedades Neurodegenerativas/patología , Animales , Movimiento Celular/fisiología , Sistema Nervioso Central/patología , Citocinas/metabolismo , Encefalomielitis Autoinmune Experimental/metabolismo , Ratones Transgénicos , Esclerosis Múltiple/patología , Enfermedades Neurodegenerativas/metabolismo , Médula Espinal/patologíaRESUMEN
Recent success with B cell depletion therapies has revitalized efforts to understand the pathogenic role of B cells in Multiple Sclerosis (MS). Using the adoptive transfer system of experimental autoimmune encephalomyelitis (EAE), a murine model of MS, we have previously shown that mice in which B cells are the only MHCII-expressing antigen presenting cell (APC) are susceptible to EAE. However, a reproducible delay in the day of onset of disease driven by exclusive B cell antigen presentation suggests that B cells require optimal conditions to function as APCs in EAE. In this study, we utilize an in vivo genetic system to conditionally and temporally regulate expression of MHCII to test the hypothesis that B cell APCs mediate attenuated and delayed neuroinflammatory T cell responses during EAE. Remarkably, induction of MHCII on B cells following the transfer of encephalitogenic CD4 T cells induced a rapid and robust form of EAE, while no change in the time to disease onset occurred for recipient mice in which MHCII is induced on a normal complement of APC subsets. Changes in CD4 T cell activation over time did not account for more rapid onset of EAE symptoms in this new B cell-mediated EAE model. Our system represents a novel model to study how the timing of pathogenic cognate interactions between lymphocytes facilitates the development of autoimmune attacks within the CNS.
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Presentación de Antígeno , Células Presentadoras de Antígenos/inmunología , Linfocitos B/inmunología , Linfocitos T CD4-Positivos/inmunología , Encefalomielitis Autoinmune Experimental/inmunología , Esclerosis Múltiple/inmunología , Animales , Células Presentadoras de Antígenos/patología , Linfocitos B/patología , Linfocitos T CD4-Positivos/patología , Encefalomielitis Autoinmune Experimental/patología , Ratones , Ratones Transgénicos , Esclerosis Múltiple/patologíaRESUMEN
The features that define autoreactive T helper (Th) cell pathogenicity remain obscure. We have previously shown that Th cells require the transcription factor Bhlhe40 to mediate experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. Here, using Bhlhe40 reporter mice and analyzing both polyclonal and TCR transgenic Th cells, we found that Bhlhe40 expression was heterogeneous after EAE induction, with Bhlhe40-expressing cells displaying marked production of IFN-γ, IL-17A, and granulocyte-macrophage colony-stimulating factor. In adoptive transfer EAE models, Bhlhe40-deficient Th1 and Th17 cells were both nonencephalitogenic. Pertussis toxin (PTX), a classical co-adjuvant for actively induced EAE, promoted IL-1ß production by myeloid cells in the draining lymph node and served as a strong stimulus for Bhlhe40 expression in Th cells. Furthermore, PTX co-adjuvanticity was Bhlhe40 dependent. IL-1ß induced Bhlhe40 expression in polarized Th17 cells, and Bhlhe40-expressing cells exhibited an encephalitogenic transcriptional signature. In vivo, IL-1R signaling was required for full Bhlhe40 expression by Th cells after immunization. Overall, we demonstrate that Bhlhe40 expression identifies encephalitogenic Th cells and defines a PTX-IL-1-Bhlhe40 pathway active in EAE.
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Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Encefalomielitis Autoinmune Experimental/inmunología , Proteínas de Homeodominio/metabolismo , Interleucina-1beta/metabolismo , Linfocitos T Colaboradores-Inductores/inmunología , Adyuvantes Inmunológicos , Traslado Adoptivo , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Citocinas/biosíntesis , Encefalomielitis Autoinmune Experimental/genética , Encefalomielitis Autoinmune Experimental/patología , Factores de Transcripción Forkhead/metabolismo , Expresión Génica , Proteínas de Homeodominio/genética , Interleucina-10/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Toxina del Pertussis/inmunología , Receptores Tipo I de Interleucina-1/deficiencia , Receptores Tipo I de Interleucina-1/genética , Receptores Tipo I de Interleucina-1/metabolismo , Transducción de Señal , Linfocitos T Colaboradores-Inductores/patologíaRESUMEN
B cells are increasingly regarded as integral to the pathogenesis of multiple sclerosis, in part as a result of the success of B cell-depletion therapy. Multiple B cell-dependent mechanisms contributing to inflammatory demyelination of the CNS have been explored using experimental autoimmune encephalomyelitis (EAE), a CD4 T cell-dependent animal model for multiple sclerosis. Although B cell Ag presentation was suggested to regulate CNS inflammation during EAE, direct evidence that B cells can independently support Ag-specific autoimmune responses by CD4 T cells in EAE is lacking. Using a newly developed murine model of in vivo conditional expression of MHC class II, we reported previously that encephalitogenic CD4 T cells are incapable of inducing EAE when B cells are the sole APC. In this study, we find that B cells cooperate with dendritic cells to enhance EAE severity resulting from myelin oligodendrocyte glycoprotein (MOG) immunization. Further, increasing the precursor frequency of MOG-specific B cells, but not the addition of soluble MOG-specific Ab, is sufficient to drive EAE in mice expressing MHCII by B cells alone. These data support a model in which expansion of Ag-specific B cells during CNS autoimmunity amplifies cognate interactions between B and CD4 T cells and have the capacity to independently drive neuroinflammation at later stages of disease.
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Presentación de Antígeno/inmunología , Linfocitos B/inmunología , Encefalomielitis Autoinmune Experimental/inmunología , Esclerosis Múltiple/inmunología , Glicoproteína Mielina-Oligodendrócito/inmunología , Inflamación Neurogénica/inmunología , Animales , Linfocitos T CD4-Positivos/inmunología , Células Dendríticas/inmunología , Encefalomielitis Autoinmune Experimental/patología , Antígenos de Histocompatibilidad Clase II/biosíntesis , Antígenos de Histocompatibilidad Clase II/inmunología , Ratones , Ratones Endogámicos C57BL , Esclerosis Múltiple/patología , Glicoproteína Mielina-Oligodendrócito/administración & dosificaciónRESUMEN
Apolipoprotein E (ApoE) functions as a ligand in receptor-mediated endocytosis of lipoprotein particles and has been demonstrated to play a role in antigen presentation. To explore the contribution of ApoE during autoimmune central nervous system (CNS) demyelination, we examined the clinical, cellular immune function, and pathologic consequences of experimental autoimmune encephalomyelitis (EAE) induction in ApoE knockout (ApoE(-/-)) mice. We observed reduced clinical severity of EAE in ApoE(-/-) mice in comparison to WT mice that was concomitant with an early reduction of dendritic cells (DCs) followed by a reduction of additional innate cells in the spinal cord at the peak of disease without any differences in axonal damage. While T cell priming was enhanced in ApoE(-/-) mice, reduced severity of EAE was also observed in ApoE(-/-) recipients of encephalitogenic wild type T cells. Expression of ApoE during EAE was elevated within the CNS of wild type mice, particularly by innate cells such as DCs. Overall, ApoE promotes clinical EAE, likely by mediation of inflammation localized within the CNS.
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Apolipoproteínas E/metabolismo , Sistema Nervioso Central/patología , Encefalomielitis Autoinmune Experimental/complicaciones , Esclerosis Múltiple/complicaciones , Animales , Presentación de Antígeno , Apolipoproteínas E/genética , Linfocitos T CD4-Positivos/patología , Receptor 1 de Quimiocinas CX3C , Células Dendríticas/inmunología , Células Dendríticas/patología , Modelos Animales de Enfermedad , Relación Dosis-Respuesta Inmunológica , Encefalitis/inducido químicamente , Encefalitis/etiología , Encefalitis/genética , Encefalitis/patología , Encefalomielitis Autoinmune Experimental/inducido químicamente , Encefalomielitis Autoinmune Experimental/genética , Adyuvante de Freund , Leucocitos Mononucleares/patología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Esclerosis Múltiple/genética , Receptores de Quimiocina/genética , Médula Espinal/metabolismo , Médula Espinal/patologíaRESUMEN
TH1 and TH17 cells mediate neuroinflammation in experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. Pathogenic TH cells in EAE must produce the pro-inflammatory cytokine granulocyte-macrophage colony stimulating factor (GM-CSF). TH cell pathogenicity in EAE is also regulated by cell-intrinsic production of the immunosuppressive cytokine interleukin 10 (IL-10). Here we demonstrate that mice deficient for the basic helix-loop-helix (bHLH) transcription factor Bhlhe40 (Bhlhe40(-/-)) are resistant to the induction of EAE. Bhlhe40 is required in vivo in a T cell-intrinsic manner, where it positively regulates the production of GM-CSF and negatively regulates the production of IL-10. In vitro, GM-CSF secretion is selectively abrogated in polarized Bhlhe40(-/-) TH1 and TH17 cells, and these cells show increased production of IL-10. Blockade of IL-10 receptor in Bhlhe40(-/-) mice renders them susceptible to EAE. These findings identify Bhlhe40 as a critical regulator of autoreactive T-cell pathogenicity.
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Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/inmunología , Encefalomielitis Autoinmune Experimental/inmunología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/inmunología , Proteínas de Homeodominio/inmunología , Interleucina-10/inmunología , Esclerosis Múltiple/inmunología , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Encefalomielitis Autoinmune Experimental/genética , Proteínas de Homeodominio/genética , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Esclerosis Múltiple/genética , Receptores de Interleucina-10/genética , Receptores de Interleucina-10/inmunología , Células TH1/inmunología , Células Th17/inmunologíaRESUMEN
The activation, differentiation, and subsequent effector functions of CD4 T cells depend on interactions with a multitude of MHC class II (MHCII)-expressing APCs. To evaluate the individual contribution of various APCs to CD4 T cell function, we have designed a new murine tool for selective in vivo expression of MHCII in subsets of APCs. Conditional expression of MHCII in B cells was achieved using a cre-loxP approach. After i.v. or s.c. priming, partial proliferation and activation of CD4 T cells was observed in mice expressing MHCII only by B cells. Restricting MHCII expression to B cells constrained secondary CD4 T cell responses in vivo, as demonstrated in a CD4 T cell-dependent model of autoimmunity, experimental autoimmune encephalomyelitis. These results highlight the limitations of B cell Ag presentation during initiation and propagation of CD4 T cell function in vivo using a novel system to study individual APCs by the conditional expression of MHCII.
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Presentación de Antígeno , Linfocitos B/inmunología , Linfocitos B/metabolismo , Linfocitos T CD4-Positivos/inmunología , Antígenos de Histocompatibilidad Clase II/metabolismo , Animales , Células Presentadoras de Antígenos/inmunología , Células Presentadoras de Antígenos/metabolismo , Línea Celular , Proliferación Celular , Encefalomielitis Autoinmune Experimental/inmunología , Antígenos de Histocompatibilidad Clase II/inmunología , Activación de Linfocitos , Ratones , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
Dendritic cells (DCs) subsets differ in precursor cell of origin, functional properties, requirements for growth factors, and dependence on transcription factors. Lymphoid-tissue resident CD8α(+) conventional DCs (cDCs) and CD11b(low/-)CD103(+) non-lymphoid DCs are developmentally related, each being dependent on FMS-like tyrosine kinase 3 ligand (Flt3L), and requiring the transcription factors Batf3, Irf8, and Id2 for development. It was recently suggested that granulocyte/macrophage colony stimulating factor (GM-CSF) was required for the development of dermal CD11b(low/-)Langerin(+)CD103(+) DCs, and that this dermal DC subset was required for priming autoreactive T cells in experimental autoimmune encephalitis (EAE). Here, we compared development of peripheral tissue DCs and susceptibility to EAE in GM-CSF receptor deficient (Csf2rb(-/-)) and Batf3(-/-) mice. We find that Batf3-dependent dermal CD11b(low/-)Langerin(+) DCs do develop in Csf2rb(-/-) mice, but that they express reduced, but not absent, levels of CD103. Further, Batf3(-/-) mice lacking all peripheral CD11b(low/-) DCs show robust Th cell priming after subcutaneous immunization and are susceptible to EAE. Our results suggest that defective T effector priming and resistance to EAE exhibited by Csf2rb(-/-) mice does not result from the absence of dermal CD11b(low/-)Langerin(+)CD103(+) DCs.
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Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Antígeno CD11b/metabolismo , Reactividad Cruzada/efectos de los fármacos , Células Dendríticas/inmunología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/farmacología , Inmunización , Proteínas Represoras/metabolismo , Linfocitos T Colaboradores-Inductores/inmunología , Animales , Antígenos CD/metabolismo , Antígenos de Superficie/metabolismo , Antígenos CD8/metabolismo , Subunidad beta Común de los Receptores de Citocinas/deficiencia , Células Dendríticas/efectos de los fármacos , Dermis/inmunología , Dermis/patología , Susceptibilidad a Enfermedades , Encefalomielitis Autoinmune Experimental/inmunología , Encefalomielitis Autoinmune Experimental/patología , Cadenas alfa de Integrinas/metabolismo , Lectinas Tipo C/metabolismo , Ganglios Linfáticos/efectos de los fármacos , Ganglios Linfáticos/inmunología , Lectinas de Unión a Manosa/metabolismo , Ratones , Ratones Endogámicos C57BL , Proteínas de la Mielina/inmunología , Glicoproteína Mielina-Oligodendrócito , Transducción de Señal/efectos de los fármacos , Bazo/efectos de los fármacos , Bazo/inmunología , Tejido Subcutáneo/efectos de los fármacos , Tejido Subcutáneo/inmunología , Linfocitos T Colaboradores-Inductores/efectos de los fármacosRESUMEN
Immature dendritic cells (DCs) specialize in antigen capture and maintain a highly dynamic pool of intracellular major histocompatibility complex class II (MHCII) that continuously recycles from peptide loading compartments to the plasma membrane and back again. This process facilitates sampling of environmental antigens for presentation to T helper cells. Here, we show that a signaling pathway mediated by the DC immunoreceptor tyrosine-based activation motif (ITAM)-containing adaptors (DAP12 and FcRγ) and Vav family guanine nucleotide exchange factors controls the half-life of surface peptide-MHCII (pMHCII) complexes and is critical for CD4 T-cell triggering in vitro. Strikingly, mice with disrupted DC ITAMs show defective T helper cell priming in vivo and are protected from experimental autoimmune encephalitis. Mechanistically, we show that deficiency in ITAM signaling results in increased pMHCII internalization, impaired recycling, and an accumulation of ubiquitinated MHCII species that are prematurely degraded in lysosomes. We propose a novel mechanism for control of T helper cell priming.
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Proteínas Adaptadoras Transductoras de Señales/inmunología , Células Dendríticas/inmunología , Antígenos de Histocompatibilidad Clase II/inmunología , Proteínas Proto-Oncogénicas c-vav/inmunología , Receptores de IgG/inmunología , Linfocitos T Colaboradores-Inductores/inmunología , Secuencias de Aminoácidos , Animales , Presentación de Antígeno , Encefalopatías/inducido químicamente , Encefalopatías/inmunología , Linfocitos T CD4-Positivos/inmunología , Encefalitis , Enfermedad de Hashimoto/inducido químicamente , Enfermedad de Hashimoto/inmunología , Antígenos de Histocompatibilidad Clase II/metabolismo , Lisosomas/metabolismo , Ratones , Transducción de Señal , Tirosina/inmunología , UbiquitinaciónRESUMEN
This study utilized an adoptive transfer model of experimental autoimmune encephalomyelitis (EAE) induction in mice to characterize the mechanisms involved in CNS accumulation of transferred and host T-cells. Using a flow cytometric technique, we examined phenotypic characteristics of CNS T-cells following disease initiation and the role of T-cell activation in CNS invasion and retention. Host T-cell activation increased cell recruitment and EAE severity. CNS antigen specific T-cells were required to induce T-cell retention within the CNS. Once retention was initiated, CNS T-cells were retained regardless of specificity. This study characterizes mechanisms involved in CNS accumulation of T-cells during EAE pathogenesis.
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Sistema Nervioso Central/inmunología , Quimiotaxis de Leucocito/inmunología , Encefalomielitis Autoinmune Experimental/inmunología , Epítopos/inmunología , Activación de Linfocitos/inmunología , Linfocitos T/inmunología , Traslado Adoptivo/métodos , Animales , Antígenos de Superficie/inmunología , Recuento de Células , Línea Celular , Movimiento Celular/inmunología , Proliferación Celular , Células Cultivadas , Sistema Nervioso Central/patología , Sistema Nervioso Central/fisiopatología , Modelos Animales de Enfermedad , Encefalomielitis Autoinmune Experimental/fisiopatología , Interacciones Huésped-Parásitos/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones TransgénicosRESUMEN
Activator protein 1 (AP-1, also known as JUN) transcription factors are dimers of JUN, FOS, MAF and activating transcription factor (ATF) family proteins characterized by basic region and leucine zipper domains. Many AP-1 proteins contain defined transcriptional activation domains, but BATF and the closely related BATF3 (refs 2, 3) contain only a basic region and leucine zipper, and are considered to be inhibitors of AP-1 activity. Here we show that Batf is required for the differentiation of IL17-producing T helper (T(H)17) cells. T(H)17 cells comprise a CD4(+) T-cell subset that coordinates inflammatory responses in host defence but is pathogenic in autoimmunity. Batf(-/-) mice have normal T(H)1 and T(H)2 differentiation, but show a defect in T(H)17 differentiation, and are resistant to experimental autoimmune encephalomyelitis. Batf(-/-) T cells fail to induce known factors required for T(H)17 differentiation, such as RORgamma t (encoded by Rorc) and the cytokine IL21 (refs 14-17). Neither the addition of IL21 nor the overexpression of RORgamma t fully restores IL17 production in Batf(-/-) T cells. The Il17 promoter is BATF-responsive, and after T(H)17 differentiation, BATF binds conserved intergenic elements in the Il17a-Il17f locus and to the Il17, Il21 and Il22 (ref. 18) promoters. These results demonstrate that the AP-1 protein BATF has a critical role in T(H)17 differentiation.
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Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Diferenciación Celular , Interleucina-17/metabolismo , Linfocitos T Colaboradores-Inductores/citología , Linfocitos T Colaboradores-Inductores/metabolismo , Factor de Transcripción AP-1/metabolismo , Animales , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/deficiencia , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Encefalomielitis Autoinmune Experimental/genética , Femenino , Regulación de la Expresión Génica , Predisposición Genética a la Enfermedad , Interleucina-17/biosíntesis , Interleucina-17/genética , Interleucinas/genética , Interleucinas/metabolismo , Interleucinas/farmacología , Ganglios Linfáticos/metabolismo , Masculino , Ratones , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares , Regiones Promotoras Genéticas/genética , Receptores de Ácido Retinoico/genética , Receptores de Ácido Retinoico/metabolismo , Receptores de Hormona Tiroidea/genética , Receptores de Hormona Tiroidea/metabolismo , Factor de Transcripción AP-1/deficiencia , Factor de Transcripción AP-1/genéticaRESUMEN
Despite extensive study, the role of phosphatidylinositol 3-kinase (PI3-kinase) activation in CD28 function has been highly contentious. To definitively address this question, we generated knock-in mice expressing mutations in two critical domains of the cytoplasmic tail of CD28. Mutation of the proximal tyrosine motif interrupted PI3-kinase binding and prevented CD28-dependent phosphorylation of protein kinase B (PKB)/Akt; however, there was no detectable effect on interleukin-2 (IL-2) secretion, expression of Bcl-X(L), or on T-cell function in vivo. Furthermore, we demonstrate that signaling initiated by the C-terminal proline motif is directly responsible for tyrosine phosphorylation of phosphoinosotide-dependent kinase 1, protein kinase C theta, and glycogen synthase kinase 3beta, as well as contributing to threonine phosphorylation of PKB. T cells mutated in this domain were profoundly impaired in IL-2 secretion, and the mice had marked impairment of humoral responses as well as less severe disease manifestations in experimental allergic encephalomyelitis. These data demonstrate that the distal proline motif initiates a critical nonredundant signaling pathway, whereas direct activation of PI3-kinase by the proximal tyrosine motif of CD28 is not required for normal T-cell function.
Asunto(s)
Antígenos CD28 , Ratones Transgénicos , Mutación , Transducción de Señal/fisiología , Secuencias de Aminoácidos , Animales , Antígenos CD28/genética , Antígenos CD28/inmunología , Encefalomielitis Autoinmune Experimental/inmunología , Activación Enzimática , Inflamación/inmunología , Interleucina-2/genética , Interleucina-2/metabolismo , Interleucina-4/inmunología , Interleucina-4/metabolismo , Activación de Linfocitos/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Bazo/citología , Linfocitos T/inmunología , Linfocitos T/metabolismo , Timo/citología , Proteína bcl-X/metabolismoRESUMEN
The localization of inflammatory foci within the cerebellum is correlated to severe clinical outcomes in multiple sclerosis (MS). Previous studies of experimental autoimmune encephalomyelitis (EAE), a model of MS, revealed distinct clinical outcomes correlated with the capacity of the animal to produce IFN-gamma. Outcomes were linked to localization of inflammatory cells in either the spinal cord (wild type [WT]) or the cerebellum and brain stem (IFN-gamma deficient). We demonstrate, using an adoptive transfer system, that the ability of the central nervous system (CNS) to sense pathogenic T cell-produced IFN-gamma during EAE initiation determines the sites of CNS pathogenesis. Transfer of WT Th1 cells into IFN-gamma receptor-deficient mice results in pathogenic invasion of the brain stem and cerebellum with attendant clinical symptoms, which are identical to the disease observed after transfer of IFN-gamma-deficient T cells to WT hosts. Inflammation of the spinal cord associated with classical EAE is abrogated in both IFN-gamma-deficient systems. Cotransfer of CNS antigen-specific WT Th1 cells with IFN-gamma-deficient T cells is sufficient to restore spinal cord invasion and block cerebellar and brain stem invasion. These data demonstrate that interaction between IFN-gamma and host CNS cells during the initiation of EAE can selectively promote or suppress neuroinflammation and pathogenesis.
Asunto(s)
Sistema Nervioso Central/patología , Encefalomielitis Autoinmune Experimental/inmunología , Interferón gamma/metabolismo , Células TH1/inmunología , Traslado Adoptivo , Animales , Sistema Nervioso Central/metabolismo , Encefalomielitis Autoinmune Experimental/metabolismo , Encefalomielitis Autoinmune Experimental/patología , Citometría de Flujo , Interleucina-17/inmunología , Interleucina-17/metabolismo , Ratones , Ratones Noqueados , Receptores de Interferón/genética , Receptor de Interferón gammaRESUMEN
Experimental autoimmune encephalomyelitis (EAE) is an animal model of multiple sclerosis and is characterized by an infiltrate of predominantly T cells and macrophages in the spinal cord and brain. In both the spinal cord and the cerebellum, Th1 cells direct inflammation to antigen-rich white matter tracts, and there is a TNFR1-dependent recruitment of CD11b(hi) cells in both regions. In the spinal cord, parenchymal invasion, demyelination and clinical symptoms are associated with TNFR1-dependant parenchymal induction (especially astrocytes) of VCAM-1 and CXCL2. None of these events occur in the cerebellum despite the fact that an inflammatory infiltrate accumulates in the perivascular space. Therefore regional specificity in astrocyte responses to inflammatory cytokines may regulate regional parenchymal infiltration and pathogenesis.
Asunto(s)
Cerebelo/inmunología , Cerebelo/patología , Encefalomielitis Autoinmune Experimental/inmunología , Encefalomielitis Autoinmune Experimental/patología , Médula Espinal/inmunología , Médula Espinal/patología , Traslado Adoptivo , Animales , Antígeno CD11b/metabolismo , Movimiento Celular/inmunología , Cerebelo/metabolismo , Quimiocina CXCL2 , Quimiocinas/metabolismo , Colorantes , Enfermedades Desmielinizantes/inmunología , Enfermedades Desmielinizantes/patología , Modelos Animales de Enfermedad , Células Endoteliales/metabolismo , Macrófagos/inmunología , Macrófagos/patología , Ratones , Ratones Congénicos , Ratones Endogámicos C57BL , Monocitos/inmunología , Monocitos/patología , Proteínas de la Mielina , Glicoproteína Asociada a Mielina/inmunología , Glicoproteína Asociada a Mielina/metabolismo , Glicoproteína Mielina-Oligodendrócito , Fibras Nerviosas Mielínicas/inmunología , Fibras Nerviosas Mielínicas/patología , Receptores Tipo I de Factores de Necrosis Tumoral/metabolismo , Médula Espinal/metabolismo , Linfocitos T/inmunología , Linfocitos T/metabolismo , Linfocitos T/patología , Antígenos Thy-1/genética , Cloruro de Tolonio , Molécula 1 de Adhesión Celular Vascular/metabolismoRESUMEN
We examined the role of tumor necrosis factor receptor 1 (TNFR1) in inflammation initiated by the adoptive transfer of central nervous system (CNS)-specific Th1 cells in experimental autoimmune encephalomyelitis, a murine model of multiple sclerosis. This adoptive transfer paradigm eliminates the confounding effects of bacterial adjuvants in the analysis of inflammation. We found that although T cells could reach the meninges and perivascular space in the absence of TNFR1, recruitment of other inflammatory cells from the blood was dramatically reduced. The reduction in the recruitment of CD11b(hi) cells correlated with a dramatic reduction in the production of the chemokines CCL2 (MCP-1) and CXLC2 (MIP-2) in TNFR1-deficient hosts. Bone marrow chimera experiments demonstrated that TNF can be effectively supplied by either the hematopoietic system or the CNS, but the essential TNFR1-responsive cells reside in the CNS. Previous work has demonstrated that microglia produce CCL2, and here we demonstrate that astrocytes and endothelial cells produced CXCL2 in the early stages of inflammation. Therefore, productive inflammation results from a conversation, or mutually responding signals, between the initiating T cells and cells in the parenchyma of the spinal cord.
Asunto(s)
Encéfalo/inmunología , Encefalomielitis Autoinmune Experimental/inmunología , Receptores del Factor de Necrosis Tumoral/fisiología , Médula Espinal/inmunología , Linfocitos T/inmunología , Traslado Adoptivo , Animales , Astrocitos/metabolismo , Células de la Médula Ósea/metabolismo , Encéfalo/metabolismo , Encéfalo/patología , Antígeno CD11b/metabolismo , Quimiocina CCL2/biosíntesis , Quimiocina CXCL2 , Quimiocinas/biosíntesis , Quimiocinas CXC/biosíntesis , Quimera , Encefalomielitis Autoinmune Experimental/metabolismo , Encefalomielitis Autoinmune Experimental/patología , Células Endoteliales/metabolismo , Ratones , Ratones Congénicos , Ratones Endogámicos C57BL , Mielitis/inmunología , Mielitis/metabolismo , Mielitis/patología , Receptores del Factor de Necrosis Tumoral/genética , Receptores Tipo I de Factores de Necrosis Tumoral , Médula Espinal/metabolismo , Médula Espinal/patología , Células TH1/inmunología , Receptores Señuelo del Factor de Necrosis TumoralRESUMEN
This paper examined heat-induced radiosensitization in two Chinese hamster heat-resistant cell lines, HR-1 and OC-14, that were isolated from the same wild-type HA-1 cell line. It found a reduction of the magnitude of heat-induced radiosensitization after exposure to 43 degrees C in both HR-1 and OC-14 cells and a similar reduction after exposure to 45 degrees C in HR-1 cells, but not in OC-14 cells. The effect of heat exposure on a class of ionizing radiation-induced DNA damage that inhibits the ability of nuclear DNA to undergo super-coiling changes was also studied using the fluorescent halo assay in these three cell lines. Wild type cells exposed to either 43 or 45 degrees C before irradiation had a DNA rewinding ability that was intermediate between control and unheated cells, a phenomenon previously described as a masking effect. This masking effect was significantly reduced in HR-1 cells exposed to either 43 or 45 degrees C or in OC-14 cells exposed to 43 degrees C under conditions that heat-induced radiosensitization was reduced. In contrast, the masking effect was not altered in OC-14 cells exposed to 45 degrees C, conditions under which heat-induced radiosensitization was similar to that observed in wild-type HA-1 cells. These results suggest that a reduction in the masking effect is associated with a reduction of the magnitude of heat-induced radiosensitization in the HR-1 and OC-14 heat-resistant cell lines. The reduction of the masking effect in the cell lines resistant to heat-induced radiosensitization was associated with neither a reduction in the magnitude of the heat-induced increase in total nuclear protein content nor major differences in the protein profiles of the nucleoids isolated from heated cells.
Asunto(s)
Hipertermia Inducida , Tolerancia a Radiación , Animales , Línea Celular , Cricetinae , Cricetulus , Daño del ADN , Proteínas Nucleares/biosíntesisRESUMEN
Nitric oxide (*NO) is a reactive nitrogen species known to be involved in cytotoxic processes. Cells respond to cytotoxic injury by stress response induction leading to the development of cellular resistance. This report describes an *NO-induced stress response in Chinese hamster fibroblasts (HA1), which leads to glutathione synthesis-dependent resistance to H2O2-mediated oxidative stress. The development of resistance to H2O2 was completely abolished by the inhibition of glutamate cysteine ligase (GCL) during the first 8 h of recovery after *NO exposure. Altered thiol metabolism was observed immediately after *NO exposure as demonstrated by up to 75% decrease in intracellular thiol pools (glutathione, gamma-glutamylcysteine, and cysteine), which then reaccumulated during the *NO-mediated development of resistance. Immunoreactive protein and activity associated with GCL decreased immediately after exposure to *NO and then reaccumulated during the development of resistance to H2O2 challenge. Moreover, compared to N2 controls the activity levels of GCL in *NO-exposed cells increased approximately twofold 24 h after H2O2 challenge. These results demonstrate that *NO exposure is capable of inducing an adaptive response to H2O2-mediated oxidative stress in mammalian cells, which involves alterations in thiol metabolism and is dependent upon glutathione synthesis and increased GCL activity.