RESUMEN
Despite the established dogma of central nervous system (CNS) immune privilege, neuroimmune interactions play an active role in diverse neurological disorders. However, the precise mechanisms underlying CNS immune surveillance remain elusive; particularly, the anatomical sites where peripheral adaptive immunity can sample CNS-derived antigens and the cellular and molecular mediators orchestrating this surveillance. Here, we demonstrate that CNS-derived antigens in the cerebrospinal fluid (CSF) accumulate around the dural sinuses, are captured by local antigen-presenting cells, and are presented to patrolling T cells. This surveillance is enabled by endothelial and mural cells forming the sinus stromal niche. T cell recognition of CSF-derived antigens at this site promoted tissue resident phenotypes and effector functions within the dural meninges. These findings highlight the critical role of dural sinuses as a neuroimmune interface, where brain antigens are surveyed under steady-state conditions, and shed light on age-related dysfunction and neuroinflammatory attack in animal models of multiple sclerosis.
Asunto(s)
Senos Craneales/inmunología , Senos Craneales/fisiología , Duramadre/inmunología , Duramadre/fisiología , Animales , Presentación de Antígeno/inmunología , Células Presentadoras de Antígenos/metabolismo , Antígenos/líquido cefalorraquídeo , Senescencia Celular , Quimiocina CXCL12/farmacología , Duramadre/irrigación sanguínea , Femenino , Homeostasis , Humanos , Inmunidad , Masculino , Ratones Endogámicos C57BL , Fenotipo , Células del Estroma/citología , Linfocitos T/citologíaRESUMEN
While intestinal Th17 cells are critical for maintaining tissue homeostasis, recent studies have implicated their roles in the development of extra-intestinal autoimmune diseases including multiple sclerosis. However, the mechanisms by which tissue Th17 cells mediate these dichotomous functions remain unknown. Here, we characterized the heterogeneity, plasticity, and migratory phenotypes of tissue Th17 cells in vivo by combined fate mapping with profiling of the transcriptomes and TCR clonotypes of over 84,000 Th17 cells at homeostasis and during CNS autoimmune inflammation. Inter- and intra-organ single-cell analyses revealed a homeostatic, stem-like TCF1+ IL-17+ SLAMF6+ population that traffics to the intestine where it is maintained by the microbiota, providing a ready reservoir for the IL-23-driven generation of encephalitogenic GM-CSF+ IFN-γ+ CXCR6+ T cells. Our study defines a direct in vivo relationship between IL-17+ non-pathogenic and GM-CSF+ and IFN-γ+ pathogenic Th17 populations and provides a mechanism by which homeostatic intestinal Th17 cells direct extra-intestinal autoimmune disease.
Asunto(s)
Autoinmunidad , Intestinos/inmunología , Células Madre/metabolismo , Células Th17/inmunología , Animales , Movimiento Celular , Células Clonales , Encefalomielitis Autoinmune Experimental/inmunología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Homeostasis , Humanos , Interferón gamma/metabolismo , Interleucina-17/metabolismo , Ratones Endogámicos C57BL , Especificidad de Órganos , ARN/metabolismo , RNA-Seq , Receptores de Antígenos de Linfocitos T/metabolismo , Receptores CXCR6/metabolismo , Receptores de Interleucina/metabolismo , Reproducibilidad de los Resultados , Familia de Moléculas Señalizadoras de la Activación Linfocitaria/metabolismo , Análisis de la Célula Individual , Bazo/metabolismoRESUMEN
Nervous system function depends on proper myelination for insulation and critical trophic support for axons. Myelination is tightly regulated spatially and temporally, but how it is controlled molecularly remains largely unknown. Here, we identified key molecular mechanisms governing the regional and temporal specificity of CNS myelination. We show that transcription factor EB (TFEB) is highly expressed by differentiating oligodendrocytes and that its loss causes precocious and ectopic myelination in many parts of the murine brain. TFEB functions cell-autonomously through PUMA induction and Bax-Bak activation to promote programmed cell death of a subset of premyelinating oligodendrocytes, allowing selective elimination of oligodendrocytes in normally unmyelinated brain regions. This pathway is conserved across diverse brain areas and is critical for myelination timing. Our findings define an oligodendrocyte-intrinsic mechanism underlying the spatiotemporal specificity of CNS myelination, shedding light on how myelinating glia sculpt the nervous system during development.
Asunto(s)
Proteínas Reguladoras de la Apoptosis/metabolismo , Apoptosis , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/metabolismo , Encéfalo/metabolismo , Vaina de Mielina/metabolismo , Neuroglía/metabolismo , Oligodendroglía/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Animales , Proteínas Reguladoras de la Apoptosis/genética , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/genética , Encéfalo/citología , Femenino , Masculino , Ratones , Ratones Noqueados , Vaina de Mielina/genética , Neuroglía/citología , Oligodendroglía/citología , Proteínas Supresoras de Tumor/genéticaRESUMEN
Although the gut microbiota can influence central nervous system (CNS) autoimmune diseases, the contribution of the intestinal epithelium to CNS autoimmunity is less clear. Here, we showed that intestinal epithelial dopamine D2 receptors (IEC DRD2) promoted sex-specific disease progression in an animal model of multiple sclerosis. Female mice lacking Drd2 selectively in intestinal epithelial cells showed a blunted inflammatory response in the CNS and reduced disease progression. In contrast, overexpression or activation of IEC DRD2 by phenylethylamine administration exacerbated disease severity. This was accompanied by altered lysozyme expression and gut microbiota composition, including reduced abundance of Lactobacillus species. Furthermore, treatment with N2-acetyl-L-lysine, a metabolite derived from Lactobacillus, suppressed microglial activation and neurodegeneration. Taken together, our study indicates that IEC DRD2 hyperactivity impacts gut microbial abundances and increases susceptibility to CNS autoimmune diseases in a female-biased manner, opening up future avenues for sex-specific interventions of CNS autoimmune diseases.
Asunto(s)
Enfermedades Autoinmunes del Sistema Nervioso , Esclerosis Múltiple , Masculino , Femenino , Ratones , Animales , Esclerosis Múltiple/metabolismo , Modelos Animales de Enfermedad , Transducción de Señal , Progresión de la Enfermedad , Receptores DopaminérgicosRESUMEN
An explosion of findings driven by powerful new technologies has expanded our understanding of microglia, the resident immune cells of the central nervous system (CNS). This wave of discoveries has fueled a growing interest in the roles that these cells play in the development of the CNS and in the neuropathology of a diverse array of disorders. In this review, we discuss the crucial roles that microglia play in shaping the brain-from their influence on neurons and glia within the developing CNS to their roles in synaptic maturation and brain wiring-as well as some of the obstacles to overcome when assessing their contributions to normal brain development. Furthermore, we examine how normal developmental functions of microglia are perturbed or remerge in neurodevelopmental and neurodegenerative disease.
Asunto(s)
Encéfalo/crecimiento & desarrollo , Sistema Nervioso Central/crecimiento & desarrollo , Microglía/metabolismo , Neuronas/metabolismo , Animales , Encéfalo/metabolismo , Encéfalo/patología , Sistema Nervioso Central/metabolismo , Sistema Nervioso Central/patología , Humanos , Microglía/patología , Enfermedades Neurodegenerativas , Neuroglía/metabolismo , Neuroglía/patología , Neuronas/patología , Transducción de Señal/genéticaRESUMEN
Self-reactive B cell progenitors are eliminated through central tolerance checkpoints, a process thought to be restricted to the bone marrow in mammals. Here, we identified a consecutive trajectory of B cell development in the meninges of mice and non-human primates. The meningeal B cells were located predominantly at the dural sinuses, where endothelial cells expressed essential niche factors to support B cell development. Parabiosis experiments together with lineage tracing showed that meningeal developing B cells were replenished continuously from hematopoietic stem cell (HSC)-derived progenitors via a circulation-independent route. Autoreactive immature B cells that recognized myelin oligodendrocyte glycoprotein (MOG), a central nervous system-specific antigen, were eliminated specifically from the meninges. Furthermore, genetic deletion of the Mog gene restored the self-reactive B cell population in the meninges. These findings identify the meninges as a distinct reservoir for B cell development, allowing in situ negative selection to ensure a locally non-self-reactive immune repertoire.
Asunto(s)
Células Dendríticas/inmunología , Células Madre Hematopoyéticas/fisiología , Indolamina-Pirrol 2,3,-Dioxigenasa/metabolismo , Meninges/inmunología , Células Plasmáticas/inmunología , Animales , Anticuerpos Neutralizantes/metabolismo , Antígeno B7-1/metabolismo , Antígenos CD28/metabolismo , Autorrenovación de las Células , Supervivencia Celular , Células Cultivadas , Humanos , Inmunidad Humoral , Memoria Inmunológica , Indolamina-Pirrol 2,3,-Dioxigenasa/genética , Ratones , Ratones Endogámicos C57BLRESUMEN
The tissue-specific deployment of highly extended neural 3' UTR isoforms, generated by alternative polyadenylation (APA), is a broad and conserved feature of metazoan genomes. However, the factors and mechanisms that control neural APA isoforms are not well understood. Here, we show that three ELAV/Hu RNA binding proteins (Elav, Rbp9, and Fne) have similar capacities to induce a lengthened 3' UTR landscape in an ectopic setting. These factors promote accumulation of chromatin-associated, 3' UTR-extended, nascent transcripts, through inhibition of proximal polyadenylation site (PAS) usage. Notably, Elav represses an unannotated splice isoform of fne, switching the normally cytoplasmic Fne toward the nucleus in elav mutants. We use genomic profiling to reveal strong and broad loss of neural APA in elav/fne double mutant CNS, the first genetic background to largely abrogate this distinct APA signature. Overall, we demonstrate how regulatory interplay and functionally overlapping activities of neural ELAV/Hu RBPs drives the neural APA landscape.
Asunto(s)
Regiones no Traducidas 3'/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Proteínas ELAV/metabolismo , Neuronas/metabolismo , Empalme Alternativo/genética , Secuencias de Aminoácidos , Animales , Línea Celular , Núcleo Celular/metabolismo , Proteínas ELAV/química , Larva/metabolismo , Mutación/genética , Poli A/metabolismo , Isoformas de Proteínas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismoRESUMEN
Dysregulation of the ubiquitin-proteasomal system (UPS) enables pathogenic accumulation of disease-driving proteins in neurons across a host of neurological disorders. However, whether and how the UPS contributes to oligodendrocyte dysfunction and repair after white matter injury (WMI) remains undefined. Here we show that the E3 ligase VHL interacts with Daam2 and their mutual antagonism regulates oligodendrocyte differentiation during development. Using proteomic analysis of the Daam2-VHL complex coupled with conditional genetic knockout mouse models, we further discovered that the E3 ubiquitin ligase Nedd4 is required for developmental myelination through stabilization of VHL via K63-linked ubiquitination. Furthermore, studies in mouse demyelination models and white matter lesions from patients with multiple sclerosis corroborate the function of this pathway during remyelination after WMI. Overall, these studies provide evidence that a signaling axis involving key UPS components contributes to oligodendrocyte development and repair and reveal a new role for Nedd4 in glial biology.
Asunto(s)
Diferenciación Celular , Proteínas de Microfilamentos/metabolismo , Ubiquitina-Proteína Ligasas Nedd4/metabolismo , Regeneración Nerviosa/genética , Enfermedades del Sistema Nervioso/genética , Oligodendroglía/fisiología , Proteína Supresora de Tumores del Síndrome de Von Hippel-Lindau/metabolismo , Proteínas de Unión al GTP rho/metabolismo , Animales , Regulación del Desarrollo de la Expresión Génica , Humanos , Ratones , Ratones Noqueados , Esclerosis Múltiple/fisiopatología , Vaina de Mielina/genética , Enfermedades del Sistema Nervioso/fisiopatología , Oligodendroglía/citología , Estabilidad Proteica , Ubiquitinación/genéticaRESUMEN
Multiple sclerosis (MS) affects more than 2.8 million people worldwide but the distribution is not even. Although over 200 gene variants have been associated with susceptibility, studies of genetically identical monozygotic twin pairs suggest that the genetic make-up is responsible for only about 20%-30% of the risk to develop disease, while the rest is contributed by milieu factors. Recently, a new, unexpected player has entered the ranks of MS-triggering or facilitating elements: the human gut microbiota. In this review, we summarize the present knowledge of microbial effects on formation of a pathogenic autoreactive immune response targeting the distant central nervous system and delineate the approaches, both in people with MS and in MS animal models, which have led to this concept. Finally, we propose that a tight combination of investigations of human patients with studies of suitable animal models is the best strategy to functionally characterize disease-associated microbiota and thereby contribute to deciphering pathogenesis of a complex human disease.
Asunto(s)
Modelos Animales de Enfermedad , Microbioma Gastrointestinal , Esclerosis Múltiple , Humanos , Esclerosis Múltiple/inmunología , Esclerosis Múltiple/etiología , Esclerosis Múltiple/microbiología , Animales , Microbioma Gastrointestinal/inmunología , Intestinos/inmunología , Intestinos/microbiología , AutoinmunidadRESUMEN
The GPR124/RECK/WNT7 pathway is an essential regulator of CNS angiogenesis and blood-brain barrier (BBB) function. GPR124, a brain endothelial adhesion seven-pass transmembrane protein, associates with RECK, which binds and stabilizes newly synthesized WNT7 that is transferred to frizzled (FZD) to initiate canonical ß-catenin signaling. GPR124 remains enigmatic: although its extracellular domain (ECD) is essential, the poorly conserved intracellular domain (ICD) appears to be variably required in mammals versus zebrafish, potentially via adaptor protein bridging of GPR124 and FZD ICDs. GPR124 ICD deletion impairs zebrafish angiogenesis, but paradoxically retains WNT7 signaling upon mammalian transfection. We thus investigated GPR124 ICD function using the mouse deletion mutant Gpr124ΔC. Despite inefficiently expressed GPR124ΔC protein, Gpr124ΔC/ΔC mice could be born with normal cerebral cortex angiogenesis, in comparison with Gpr124-/- embryonic lethality, forebrain avascularity and hemorrhage. Gpr124ΔC/ΔC vascular phenotypes were restricted to sporadic ganglionic eminence angiogenic defects, attributable to impaired GPR124ΔC protein expression. Furthermore, Gpr124ΔC and the recombinant GPR124 ECD rescued WNT7 signaling in culture upon brain endothelial Gpr124 knockdown. Thus, in mice, GPR124-regulated CNS forebrain angiogenesis and BBB function are exerted by ICD-independent functionality, extending the signaling mechanisms used by adhesion seven-pass transmembrane receptors.
Asunto(s)
Barrera Hematoencefálica , Encéfalo , Neovascularización Fisiológica , Receptores Acoplados a Proteínas G , Animales , Barrera Hematoencefálica/metabolismo , Barrera Hematoencefálica/embriología , Neovascularización Fisiológica/genética , Receptores Acoplados a Proteínas G/metabolismo , Receptores Acoplados a Proteínas G/genética , Ratones , Encéfalo/metabolismo , Encéfalo/embriología , Dominios Proteicos , Ratones Noqueados , Transducción de Señal , Proteínas Wnt/metabolismo , Proteínas Wnt/genética , Humanos , Células Endoteliales/metabolismo , Angiogénesis , Proteínas Ligadas a GPIRESUMEN
The Hsp90 chaperone machinery in eukaryotes comprises a number of distinct accessory factors. Cns1 is one of the few essential co-chaperones in yeast, but its structure and function remained unknown. Here, we report the X-ray structure of the Cns1 fold and NMR studies on the partly disordered, essential segment of the protein. We demonstrate that Cns1 is important for maintaining translation elongation, specifically chaperoning the elongation factor eEF2. In this context, Cns1 interacts with the novel co-factor Hgh1 and forms a quaternary complex together with eEF2 and Hsp90. The in vivo folding and solubility of eEF2 depend on the presence of these proteins. Chaperoning of eEF2 by Cns1 is essential for yeast viability and requires a defined subset of the Hsp90 machinery as well as the identified eEF2 recruiting factor Hgh1.
Asunto(s)
Proteínas HSP90 de Choque Térmico/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Chaperonas Moleculares/metabolismo , Extensión de la Cadena Peptídica de Translación , Factor 2 de Elongación Peptídica/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Cristalografía por Rayos X , Peptidil-Prolil Isomerasa F , Ciclofilinas/genética , Ciclofilinas/metabolismo , Proteínas HSP90 de Choque Térmico/química , Proteínas HSP90 de Choque Térmico/genética , Péptidos y Proteínas de Señalización Intracelular/química , Péptidos y Proteínas de Señalización Intracelular/genética , Modelos Moleculares , Chaperonas Moleculares/química , Chaperonas Moleculares/genética , Resonancia Magnética Nuclear Biomolecular , Factor 2 de Elongación Peptídica/química , Factor 2 de Elongación Peptídica/genética , Unión Proteica , Pliegue de Proteína , Dominios y Motivos de Interacción de Proteínas , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Relación Estructura-ActividadRESUMEN
Viral infection is frequently assayed by ongoing expression of viral genes. These assays fail to identify cells that have been exposed to the virus but limit or inhibit viral replication. To address this limitation, we used a dual-labeling vesicular stomatitis virus (DL-VSV), which has a deletion of the viral glycoprotein gene, to allow evaluation of primary infection outcomes. This virus encodes Cre, which can stably mark any cell with even a minimal level of viral gene expression. Additionally, the virus encodes GFP, which distinguishes cells with higher levels of viral gene expression, typically due to genome replication. Stereotactic injections of DL-VSV into the murine brain showed that different cell types had very different responses to the virus. Almost all neurons hosted high levels of viral gene expression, while glial cells varied in their responses. Astrocytes (Sox9+) were predominantly productively infected, while oligodendrocytes (Sox10+) were largely abortively infected. Microglial cells (Iba1+) were primarily uninfected. Furthermore, we monitored the early innate immune response to viral infection and identified unique patterns of interferon (IFN) induction. Shortly after infection, microglia were the main producers of IFNb, whereas later, oligodendrocytes were the main producers. IFNb+ cells were primarily abortively infected regardless of cell type. Last, we investigated whether IFN signaling had any impact on the outcome of primary infection and did not observe significant changes, suggesting that intrinsic factors are likely responsible for determining the outcome of primary infection.
Asunto(s)
Astrocitos , Animales , Ratones , Astrocitos/virología , Astrocitos/metabolismo , Replicación Viral , Microglía/virología , Microglía/metabolismo , Microglía/inmunología , Neuronas/virología , Neuronas/metabolismo , Factor de Transcripción SOX9/metabolismo , Factor de Transcripción SOX9/genética , Vesiculovirus/fisiología , Vesiculovirus/inmunología , Vesiculovirus/genética , Oligodendroglía/virología , Oligodendroglía/metabolismo , Estomatitis Vesicular/virología , Estomatitis Vesicular/inmunología , Inmunidad Innata , Ratones Endogámicos C57BL , Encéfalo/virología , Encéfalo/metabolismo , Encéfalo/inmunología , Neuroglía/virología , Neuroglía/metabolismoRESUMEN
Chronic inflammatory diseases are influenced by dysregulation of cytokines. Among them, granulocyte macrophage colony stimulating factor (GM-CSF) is crucial for the pathogenic function of T cells in preclinical models of autoimmunity. To study the impact of dysregulated GM-CSF expression in vivo, we generated a transgenic mouse line allowing the induction of GM-CSF expression in mature, peripheral helper T (Th) cells. Antigen-independent GM-CSF release led to the invasion of inflammatory myeloid cells into the central nervous system (CNS), which was accompanied by the spontaneous development of severe neurological deficits. CNS-invading phagocytes produced reactive oxygen species and exhibited a distinct genetic signature compared to myeloid cells invading other organs. We propose that the CNS is particularly vulnerable to the attack of monocyte-derived phagocytes and that the effector functions of GM-CSF-expanded myeloid cells are in turn guided by the tissue microenvironment.
Asunto(s)
Sistema Nervioso Central/inmunología , Sistema Nervioso Central/patología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/inmunología , Fagocitos/inmunología , Animales , Citometría de Flujo , Inmunohistoquímica , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Modelos Animales , Reacción en Cadena de la PolimerasaRESUMEN
Traumatic injuries of the central nervous system (CNS) affect millions of people worldwide, and they can lead to severely damaging consequences such as permanent disability and paralysis. Multiple factors can obstruct recovery after CNS injury. One of the most significant is the progressive neuronal death that follows the initial mechanical impact, leading to the loss of undamaged cells via a process termed secondary neurodegeneration. Efforts to define treatments that limit the spread of damage, while important, have been largely ineffectual owing to gaps in the mechanistic understanding that underlies the persisting neuronal cell death. Inflammation, with its influx of immune cells that occurs shortly after injury, has been associated with secondary neurodegeneration. However, the role of the immune system after CNS injury is far more complex. Studies have indicated that the immune response after CNS injury is detrimental, owing to immune cell-produced factors (e.g., pro-inflammatory cytokines, free radicals, neurotoxic glutamate) that worsen tissue damage. Our lab and others have also demonstrated the beneficial immune response that occurs after CNS injury, with the release of growth factors such as brain-derived growth factor (BDNF) and interleukin (IL-10) and the clearance of apoptotic and myelin debris by immune cells1-4. In this review, we first discuss the multifaceted roles of the immune system after CNS injury. We then speculate on how advancements in single-cell RNA technologies can dramatically change our understanding of the immune response, how the spinal cord meninges serve as an important site for hosting immunological processes critical for recovery, and how the origin of peripherally recruited immune cells impacts their function in the injured CNS.
Asunto(s)
Sistema Nervioso Central , Traumatismos de la Médula Espinal , Humanos , Inflamación , Citocinas , Sistema Inmunológico , InmunidadRESUMEN
Multiple sclerosis (MS) is an incurable autoimmune disease and is currently treated by systemic immunosuppressants with off-target side effects. Although aberrant myeloid function is often observed in MS plaques in the central nervous system (CNS), the role of myeloid cells in therapeutic intervention is currently overlooked. Here, we developed a myeloid cell-based strategy to reduce the disease burden in experimental autoimmune encephalomyelitis (EAE), a mouse model of progressive MS. We developed monocyte-adhered microparticles ("backpacks") for activating myeloid cell phenotype to an anti-inflammatory state through localized interleukin-4 and dexamethasone signals. We demonstrate that backpack-laden monocytes infiltrated into the inflamed CNS and modulated both the local and systemic immune responses. Within the CNS, backpack-carrying monocytes regulated both the infiltrating and tissue-resident myeloid cell compartments in the spinal cord for functions related to antigen presentation and reactive species production. Treatment with backpack-monocytes also decreased the level of systemic pro-inflammatory cytokines. Additionally, backpack-laden monocytes induced modulatory effects on TH1 and TH17 populations in the spinal cord and blood, demonstrating cross talk between the myeloid and lymphoid arms of disease. Backpack-carrying monocytes conferred therapeutic benefit in EAE mice, as quantified by improved motor function. The use of backpack-laden monocytes offers an antigen-free, biomaterial-based approach to precisely tune cell phenotype in vivo, demonstrating the utility of myeloid cells as a therapeutic modality and target.
Asunto(s)
Encefalomielitis Autoinmune Experimental , Esclerosis Múltiple , Ratones , Animales , Esclerosis Múltiple/terapia , Células Mieloides , Sistema Nervioso Central , Monocitos , Ratones Endogámicos C57BLRESUMEN
In multiple sclerosis (MS), pathogenic T cell responses are known to be important drivers of autoimmune inflammation. However, increasing evidence suggests an additional role for B cells, which may contribute to pathogenesis via antigen presentation and production of proinflammatory cytokines. However, these B cell effector functions are not featured well in classical experimental autoimmune encephalomyelitis (EAE) mouse models. Here, we compared properties of myelin oligodendrocyte glycoprotein (MOG)-specific and polyclonal B cells and developed an adjuvant-free cotransfer EAE mouse model, where highly activated, MOG-specific induced germinal center B cells provide the critical stimulus for disease development. We could show that high levels of MOG-specific immunoglobulin G (IgGs) are not required for EAE development, suggesting that antigen presentation and activation of cognate T cells by B cells may be important for pathogenesis. As our model allows for B cell manipulation prior to transfer, we found that overexpression of the proinflammatory cytokine interleukin (IL)-6 by MOG-specific B cells leads to an accelerated EAE onset accompanied by activation/expansion of the myeloid compartment rather than a changed T cell response. Accordingly, knocking out IL-6 or tumor necrosis factor α in MOG-specific B cells via CRISPR-Cas9 did not affect activation of pathogenic T cells. In summary, we generated a tool to dissect pathogenic B cell effector function in EAE development, which should improve our understanding of pathogenic processes in MS.
Asunto(s)
Encefalomielitis Autoinmune Experimental , Esclerosis Múltiple , Ratones , Animales , Citocinas , Autoinmunidad , Glicoproteína Mielina-Oligodendrócito , Interleucina-6 , Ratones Endogámicos C57BLRESUMEN
The CNS of the protovertebrate Ciona intestinalis contains a single cluster of dopaminergic (DA) neurons, the coronet cells, which have been likened to the hypothalamus of vertebrates. Whole-embryo single-cell RNA sequencing (RNA-seq) assays identified Ptf1a as the most strongly expressed cell-specific transcription factor (TF) in DA/coronet cells. Knockdown of Ptf1a activity results in their loss, while misexpression results in the appearance of supernumerary DA/coronet cells. Photoreceptor cells and ependymal cells are the most susceptible to transformation, and both cell types express high levels of Meis Coexpression of both Ptf1a and Meis caused the wholesale transformation of the entire CNS into DA/coronet cells. We therefore suggest that the reiterative use of functional manipulations and single-cell RNA-seq assays is an effective means for the identification of regulatory cocktails underlying the specification of specific cell identities.
Asunto(s)
Ciona intestinalis/genética , Neuronas Dopaminérgicas/metabolismo , Animales , Diferenciación Celular , Ciona intestinalis/embriología , Ciona intestinalis/crecimiento & desarrollo , Ciona intestinalis/metabolismo , Neuronas Dopaminérgicas/citología , Embrión no Mamífero/metabolismo , Perfilación de la Expresión Génica , Redes Reguladoras de Genes , Análisis de la Célula Individual , Factores de Transcripción/metabolismoRESUMEN
A diverse number of DNA and RNA viruses have the potential to invade the central nervous system (CNS), causing inflammation and injury to cells that have a limited capacity for repair and regeneration. While rare, viral encephalitis in humans is often fatal and survivors commonly suffer from permanent neurological sequelae including seizures. Established treatment options are extremely limited, predominantly relying on vaccines, antivirals, or supportive care. Many viral CNS infections are characterized by the presence of antiviral antibodies in the cerebral spinal fluid (CSF), indicating local maintenance of protective antibody secreting cells. However, the mechanisms maintaining these humoral responses are poorly characterized. Furthermore, while both viral and autoimmune encephalitis are associated with the recruitment of diverse B cell subsets to the CNS, their protective and pathogenic roles aside from antibody production are just beginning to be understood. This review will focus on the relevance of B cell responses to viral CNS infections, with an emphasis on the importance of intrathecal immunity and the potential contribution to autoimmunity. Specifically, it will summarize the newest data characterizing B cell activation, differentiation, migration, and localization in clinical samples as well as experimental models of acute and persistent viral encephalitis.
Asunto(s)
Enfermedades Virales del Sistema Nervioso Central , Encefalitis Viral , Antivirales , Linfocitos B , Sistema Nervioso Central , Enfermedades Virales del Sistema Nervioso Central/patología , Encefalitis Viral/patología , HumanosRESUMEN
The immune cells of the central nervous system (CNS) comprise parenchymal microglia and at the CNS border regions meningeal, perivascular, and choroid plexus macrophages (collectively called CNS-associated macrophages, CAMs). While previous work has shown that microglial properties depend on environmental signals from the commensal microbiota, the effects of microbiota on CAMs are unknown. By combining several microbiota manipulation approaches, genetic mouse models, and single-cell RNA-sequencing, we have characterized CNS myeloid cell composition and function. Under steady-state conditions, the transcriptional profiles and numbers of choroid plexus macrophages were found to be tightly regulated by complex microbiota. In contrast, perivascular and meningeal macrophages were affected to a lesser extent. An acute perturbation through viral infection evoked an attenuated immune response of all CAMs in germ-free mice. We further assessed CAMs in a more chronic pathological state in 5xFAD mice, a model for Alzheimer's disease, and found enhanced amyloid beta uptake exclusively by perivascular macrophages in germ-free 5xFAD mice. Our results aid the understanding of distinct microbiota-CNS macrophage interactions during homeostasis and disease, which could potentially be targeted therapeutically.
Asunto(s)
Enfermedad de Alzheimer/inmunología , Bacterias/crecimiento & desarrollo , Sistema Nervioso Central/inmunología , Homeostasis , Macrófagos/inmunología , Células Mieloides/inmunología , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/microbiología , Enfermedad de Alzheimer/patología , Animales , Bacterias/clasificación , Bacterias/metabolismo , Sistema Nervioso Central/metabolismo , Sistema Nervioso Central/microbiología , Sistema Nervioso Central/patología , Femenino , Macrófagos/metabolismo , Macrófagos/microbiología , Macrófagos/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Microbiota , Células Mieloides/metabolismo , Células Mieloides/microbiología , Células Mieloides/patología , TranscriptomaRESUMEN
The CNS has traditionally been considered an immune-privileged organ, but recent studies have identified a plethora of immune cells in the choroid plexus, meninges, perivascular spaces, and cribriform plate. Although those immune cells are crucial for the maintenance of CNS homeostasis and for neural protection against infections, they can lead to neuroinflammation in some circumstances. The blood and the lymphatic vasculatures exhibit distinct structural and molecular features depending on their location in the CNS, greatly influencing the compartmentalization and the nature of CNS immune responses. In this review, we discuss how endothelial cells regulate the migration and the functions of T cells in the CNS both at steady-state and in murine models of neuroinflammation, with a special focus on the anatomical, cellular, and molecular mechanisms implicated in EAE.