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1.
Nat Immunol ; 17(10): 1206-1215, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27548434

RESUMEN

Thymic epithelial cell differentiation, growth and function depend on the expression of the transcription factor Foxn1; however, its target genes have never been physically identified. Using static and inducible genetic model systems and chromatin studies, we developed a genome-wide map of direct Foxn1 target genes for postnatal thymic epithelia and defined the Foxn1 binding motif. We determined the function of Foxn1 in these cells and found that, in addition to the transcriptional control of genes involved in the attraction and lineage commitment of T cell precursors, Foxn1 regulates the expression of genes involved in antigen processing and thymocyte selection. Thus, critical events in thymic lympho-stromal cross-talk and T cell selection are indispensably choreographed by Foxn1.


Asunto(s)
Células Epiteliales/fisiología , Factores de Transcripción Forkhead/metabolismo , Células Precursoras de Linfocitos T/fisiología , Linfocitos T/fisiología , Timo/fisiología , Animales , Presentación de Antígeno/genética , Comunicación Celular , Diferenciación Celular/genética , Linaje de la Célula/genética , Células Cultivadas , Selección Clonal Mediada por Antígenos/genética , Factores de Transcripción Forkhead/genética , Regulación de la Expresión Génica , Genoma/genética , Ratones , Ratones Endogámicos C57BL , Ratones Mutantes , Ratones Transgénicos
2.
Proc Natl Acad Sci U S A ; 121(7): e2311049121, 2024 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-38319973

RESUMEN

Intrathecal synthesis of central nervous system (CNS)-reactive autoantibodies is observed across patients with autoimmune encephalitis (AE), who show multiple residual neurobehavioral deficits and relapses despite immunotherapies. We leveraged two common forms of AE, mediated by leucine-rich glioma inactivated-1 (LGI1) and contactin-associated protein-like 2 (CASPR2) antibodies, as human models to comprehensively reconstruct and profile cerebrospinal fluid (CSF) B cell receptor (BCR) characteristics. We hypothesized that the resultant observations would both inform the observed therapeutic gap and determine the contribution of intrathecal maturation to pathogenic B cell lineages. From the CSF of three patients, 381 cognate-paired IgG BCRs were isolated by cell sorting and scRNA-seq, and 166 expressed as monoclonal antibodies (mAbs). Sixty-two percent of mAbs from singleton BCRs reacted with either LGI1 or CASPR2 and, strikingly, this rose to 100% of cells in clonal groups with ≥4 members. These autoantigen-reactivities were more concentrated within antibody-secreting cells (ASCs) versus B cells (P < 0.0001), and both these cell types were more differentiated than LGI1- and CASPR2-unreactive counterparts. Despite greater differentiation, autoantigen-reactive cells had acquired few mutations intrathecally and showed minimal variation in autoantigen affinities within clonal expansions. Also, limited CSF T cell receptor clonality was observed. In contrast, a comparison of germline-encoded BCRs versus the founder intrathecal clone revealed marked gains in both affinity and mutational distances (P = 0.004 and P < 0.0001, respectively). Taken together, in patients with LGI1 and CASPR2 antibody encephalitis, our results identify CSF as a compartment with a remarkably high frequency of clonally expanded autoantigen-reactive ASCs whose BCR maturity appears dominantly acquired outside the CNS.


Asunto(s)
Enfermedades Autoinmunes del Sistema Nervioso , Encefalitis , Glioma , Enfermedad de Hashimoto , Humanos , Leucina , Péptidos y Proteínas de Señalización Intracelular , Recurrencia Local de Neoplasia , Autoanticuerpos , Autoantígenos
3.
Brain ; 147(4): 1130-1148, 2024 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-38092513

RESUMEN

Herpes simplex virus encephalitis (HSE) is the leading cause of non-epidemic encephalitis in the developed world and, despite antiviral therapy, mortality and morbidity is high. The emergence of post-HSE autoimmune encephalitis reveals a new immunological paradigm in autoantibody-mediated disease. A reductionist evaluation of the immunobiological mechanisms in HSE is crucial to dissect the origins of post-viral autoimmunity and supply rational approaches to the selection of immunotherapeutics. Herein, we review the latest evidence behind the phenotypic progression and underlying immunobiology of HSE including the cytokine/chemokine environment, the role of pathogen-recognition receptors, T- and B-cell immunity and relevant inborn errors of immunity. Second, we provide a contemporary review of published patients with post-HSE autoimmune encephalitis from a combined cohort of 110 patients. Third, we integrate novel mechanisms of autoimmunization in deep cervical lymph nodes to explore hypotheses around post-HSE autoimmune encephalitis and challenge these against mechanisms of molecular mimicry and others. Finally, we explore translational concepts where neuroglial surface autoantibodies have been observed with other neuroinfectious diseases and those that generate brain damage including traumatic brain injury, ischaemic stroke and neurodegenerative disease. Overall, the clinical and immunological landscape of HSE is an important and evolving field, from which precision immunotherapeutics could soon emerge.


Asunto(s)
Enfermedades Autoinmunes del Sistema Nervioso , Isquemia Encefálica , Encefalitis por Herpes Simple , Enfermedades Neurodegenerativas , Accidente Cerebrovascular , Humanos , Autoinmunidad , Encefalitis por Herpes Simple/tratamiento farmacológico , Encefalitis por Herpes Simple/patología , Autoanticuerpos , Simplexvirus
4.
Proc Natl Acad Sci U S A ; 119(24): e2121804119, 2022 06 14.
Artículo en Inglés | MEDLINE | ID: mdl-35666871

RESUMEN

Neuromyelitis optica spectrum disorders (NMOSDs) are caused by immunoglobulin G (IgG) autoantibodies directed against the water channel aquaporin-4 (AQP4). In NMOSDs, discrete clinical relapses lead to disability and are robustly prevented by the anti-CD20 therapeutic rituximab; however, its mechanism of action in autoantibody-mediated disorders remains poorly understood. We hypothesized that AQP4-IgG production in germinal centers (GCs) was a core feature of NMOSDs and could be terminated by rituximab. To investigate this directly, deep cervical lymph node (dCLN) aspirates (n = 36) and blood (n = 406) were studied in a total of 63 NMOSD patients. Clinical relapses were associated with AQP4-IgM generation or shifts in AQP4-IgG subclasses (odds ratio = 6.0; range of 3.3 to 10.8; P < 0.0001), features consistent with GC activity. From seven dCLN aspirates of patients not administered rituximab, AQP4-IgGs were detected alongside specific intranodal synthesis of AQP4-IgG. AQP4-reactive B cells were isolated from unmutated naive and mutated memory populations in both blood and dCLNs. After rituximab administration, fewer clinical relapses (annual relapse rate of 0.79 to 0; P < 0.001) were accompanied by marked reductions in both AQP4-IgG (fourfold; P = 0.004) and intranodal B cells (430-fold; P < 0.0001) from 11 dCLNs. Our findings implicate ongoing GC activity as a rituximab-sensitive driver of AQP4 antibody production. They may explain rituximab's clinical efficacy in several autoantibody-mediated diseases and highlight the potential value of direct GC measurements across autoimmune conditions.


Asunto(s)
Acuaporina 4 , Centro Germinal , Factores Inmunológicos , Neuromielitis Óptica , Rituximab , Acuaporina 4/efectos de los fármacos , Acuaporina 4/metabolismo , Autoanticuerpos , Centro Germinal/patología , Humanos , Factores Inmunológicos/farmacología , Factores Inmunológicos/uso terapéutico , Ganglios Linfáticos/metabolismo , Neuromielitis Óptica/tratamiento farmacológico , Rituximab/farmacología , Rituximab/uso terapéutico
5.
Genome Res ; 31(6): 1069-1081, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-34011578

RESUMEN

Single-cell RNA sequencing (scRNA-seq) is a widely used method for identifying cell types and trajectories in biologically heterogeneous samples, but it is limited in its detection and quantification of lowly expressed genes. This results in missing important biological signals, such as the expression of key transcription factors (TFs) driving cellular differentiation. We show that targeted sequencing of ∼1000 TFs (scCapture-seq) in iPSC-derived neuronal cultures greatly improves the biological information garnered from scRNA-seq. Increased TF resolution enhanced cell type identification, developmental trajectories, and gene regulatory networks. This allowed us to resolve differences among neuronal populations, which were generated in two different laboratories using the same differentiation protocol. ScCapture-seq improved TF-gene regulatory network inference and thus identified divergent patterns of neurogenesis into either excitatory cortical neurons or inhibitory interneurons. Furthermore, scCapture-seq revealed a role for of retinoic acid signaling in the developmental divergence between these different neuronal populations. Our results show that TF targeting improves the characterization of human cellular models and allows identification of the essential differences between cellular populations, which would otherwise be missed in traditional scRNA-seq. scCapture-seq TF targeting represents a cost-effective enhancement of scRNA-seq, which could be broadly applied to improve scRNA-seq resolution.


Asunto(s)
Células Madre Pluripotentes Inducidas , Análisis de la Célula Individual , Perfilación de la Expresión Génica/métodos , Redes Reguladoras de Genes , Humanos , Células Madre Pluripotentes Inducidas/metabolismo , Análisis de Secuencia de ARN/métodos , Análisis de la Célula Individual/métodos , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
6.
Br J Psychiatry ; 224(6): 252-257, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38699852

RESUMEN

Leucine-rich glioma-inactivated 1-antibody-encephalitis is a treatable and potentially reversible cause of cognitive and psychiatric presentations, and may mimic cognitive decline, rapidly progressive dementia and complex psychosis in older patients. This aetiology is of immediate relevance given the alternative treatment pathway required, compared with other conditions presenting with cognitive deficits.


Asunto(s)
Autoanticuerpos , Demencia , Humanos , Demencia/terapia , Autoanticuerpos/sangre , Encefalitis/terapia , Encefalitis/diagnóstico , Encefalitis/inmunología , Péptidos y Proteínas de Señalización Intracelular , Diagnóstico Diferencial , Anciano , Servicios de Salud Mental , Femenino , Masculino
7.
J Immunol ; 2022 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-36375838

RESUMEN

In the thymus, cortical thymic epithelial cells (cTECs) and medullary thymic epithelial cells support αßT cell development from lymphoid progenitors. For cTECs, expression of a specialized gene signature that includes Cxcl12, Dll4, and Psmb11 enables the cortex to support T lineage commitment and the generation and selection of CD4+CD8+ thymocytes. Although the importance of cTECs in T cell development is well defined, mechanisms that shape the cTEC compartment and regulate its functional specialization are unclear. Using a Cxcl12 DsRed reporter mouse model, we show that changes in Cxcl12 expression reveal a developmentally regulated program of cTEC heterogeneity. Although cTECs are uniformly Cxcl12 DsRed+ during neonatal stages, progression through postnatal life triggers the appearance of Cxcl12 DsRed- cTECs that continue to reside in the cortex alongside their Cxcl12 DsRed+ counterparts. This appearance of Cxcl12 DsRed- cTECs is controlled by maturation of CD4-CD8-, but not CD4+CD8+, thymocytes, demonstrating that stage-specific thymocyte cross-talk controls cTEC heterogeneity. Importantly, although fate-mapping experiments show both Cxcl12 DsRed+ and Cxcl12 DsRed- cTECs share a common Foxn1 + cell origin, RNA sequencing analysis shows Cxcl12 DsRed- cTECs no longer express Foxn1, which results in loss of the FOXN1-dependent cTEC gene signature and may explain the reduced capacity of Cxcl12 DsRed- cTECs for thymocyte interactions. In summary, our study shows that shaping of the cTEC compartment during the life course occurs via stage-specific thymocyte cross-talk, which drives loss of Foxn1 expression and its key target genes, which may then determine the functional competence of the thymic cortex.

8.
J Immunol ; 2022 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-36427001

RESUMEN

In the thymus, cortical thymic epithelial cells (cTECs) and medullary thymic epithelial cells support αßT cell development from lymphoid progenitors. For cTECs, expression of a specialized gene signature that includes Cxcl12, Dll4, and Psmb11 enables the cortex to support T lineage commitment and the generation and selection of CD4+CD8+ thymocytes. Although the importance of cTECs in T cell development is well defined, mechanisms that shape the cTEC compartment and regulate its functional specialization are unclear. Using a Cxcl12DsRed reporter mouse model, we show that changes in Cxcl12 expression reveal a developmentally regulated program of cTEC heterogeneity. Although cTECs are uniformly Cxcl12DsRed+ during neonatal stages, progression through postnatal life triggers the appearance of Cxcl12DsRed- cTECs that continue to reside in the cortex alongside their Cxcl12DsRed+ counterparts. This appearance of Cxcl12DsRed- cTECs is controlled by maturation of CD4-CD8-, but not CD4+CD8+, thymocytes, demonstrating that stage-specific thymocyte cross-talk controls cTEC heterogeneity. Importantly, although fate-mapping experiments show both Cxcl12DsRed+ and Cxcl12DsRed- cTECs share a common Foxn1+ cell origin, RNA sequencing analysis shows Cxcl12DsRed- cTECs no longer express Foxn1, which results in loss of the FOXN1-dependent cTEC gene signature and may explain the reduced capacity of Cxcl12DsRed- cTECs for thymocyte interactions. In summary, our study shows that shaping of the cTEC compartment during the life course occurs via stage-specific thymocyte cross-talk, which drives loss of Foxn1 expression and its key target genes, which may then determine the functional competence of the thymic cortex.

9.
Brain ; 145(8): 2742-2754, 2022 08 27.
Artículo en Inglés | MEDLINE | ID: mdl-35680425

RESUMEN

Autoantibodies against the extracellular domain of the N-methyl-d-aspartate receptor (NMDAR) NR1 subunit cause a severe and common form of encephalitis. To better understand their generation, we aimed to characterize and identify human germinal centres actively participating in NMDAR-specific autoimmunization by sampling patient blood, CSF, ovarian teratoma tissue and, directly from the putative site of human CNS lymphatic drainage, cervical lymph nodes. From serum, both NR1-IgA and NR1-IgM were detected more frequently in NMDAR-antibody encephalitis patients versus controls (both P < 0.0001). Within patients, ovarian teratoma status was associated with a higher frequency of NR1-IgA positivity in serum (OR = 3.1; P < 0.0001) and CSF (OR = 3.8, P = 0.047), particularly early in disease and before ovarian teratoma resection. Consistent with this immunoglobulin class bias, ovarian teratoma samples showed intratumoral production of both NR1-IgG and NR1-IgA and, by single cell RNA sequencing, contained expanded highly-mutated IgA clones with an ovarian teratoma-restricted B cell population. Multiplex histology suggested tertiary lymphoid architectures in ovarian teratomas with dense B cell foci expressing the germinal centre marker BCL6, CD21+ follicular dendritic cells, and the NR1 subunit, alongside lymphatic vessels and high endothelial vasculature. Cultured teratoma explants and dissociated intratumoral B cells secreted NR1-IgGs in culture. Hence, ovarian teratomas showed structural and functional evidence of NR1-specific germinal centres. On exploring classical secondary lymphoid organs, B cells cultured from cervical lymph nodes of patients with NMDAR-antibody encephalitis produced NR1-IgG in 3/7 cultures, from patients with the highest serum NR1-IgG levels (P < 0.05). By contrast, NR1-IgG secretion was observed neither from cervical lymph nodes in disease controls nor in patients with adequately resected ovarian teratomas. Our multimodal evaluations provide convergent anatomical and functional evidence of NMDAR-autoantibody production from active germinal centres within both intratumoral tertiary lymphoid structures and traditional secondary lymphoid organs, the cervical lymph nodes. Furthermore, we develop a cervical lymph node sampling protocol that can be used to directly explore immune activity in health and disease at this emerging neuroimmune interface.


Asunto(s)
Encefalitis Antirreceptor N-Metil-D-Aspartato , Vasos Linfáticos , Teratoma , Autoanticuerpos , Femenino , Centro Germinal , Humanos , Inmunoglobulina A , Inmunoglobulina G , Neoplasias Ováricas , Receptores de N-Metil-D-Aspartato
10.
J Biol Chem ; 295(10): 2948-2958, 2020 03 06.
Artículo en Inglés | MEDLINE | ID: mdl-31914405

RESUMEN

Forkhead box N1 (FOXN1) is a member of the forkhead box family of transcription factors and plays an important role in thymic epithelial cell differentiation and development. FOXN1 mutations in humans and mice give rise to the "nude" phenotype, which is marked by athymia. FOXN1 belongs to a subset of the FOX family that recognizes an alternative forkhead-like (FHL) consensus sequence (GACGC) that is different from the more widely recognized forkhead (FKH) sequence RYAAAYA (where R is purine, and Y is pyrimidine). Here, we present the FOXN1 structure in complex with DNA containing an FHL motif at 1.6 Å resolution, in which the DNA sequence is recognized by a mixture of direct and water-mediated contacts provided by residues in an α-helix inserted in the DNA major groove (the recognition helix). Comparisons with the structure of other FOX family members revealed that the FKH and FHL DNA sequences are bound in two distinct modes, with partially different registers for the protein DNA contacts. We identified a single alternative rotamer within the recognition helix itself as an important determinant of DNA specificity and found protein sequence features in the recognition helix that could be used to predict the specificity of other FOX family members. Finally, we demonstrate that the C-terminal region of FOXN1 is required for high-affinity DNA binding and that FOXN1 has a significantly reduced affinity for DNA that contains 5'-methylcytosine, which may have implications for the role of FOXN1 in thymic involution.


Asunto(s)
ADN/metabolismo , Factores de Transcripción Forkhead/metabolismo , Secuencia de Aminoácidos , Secuencia de Bases , Sitios de Unión , Cristalografía por Rayos X , ADN/química , Metilación de ADN , Ensayo de Cambio de Movilidad Electroforética , Factores de Transcripción Forkhead/química , Factores de Transcripción Forkhead/genética , Humanos , Unión Proteica , Conformación Proteica en Hélice alfa , Estructura Terciaria de Proteína , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/química , Proteínas Recombinantes/aislamiento & purificación , Alineación de Secuencia
11.
J Neurol Neurosurg Psychiatry ; 92(3): 291-294, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33219046

RESUMEN

OBJECTIVE: To generate a score which clinically identifies surface-directed autoantibodies in adults with new-onset focal epilepsy, and evaluate the value of immunotherapy in this clinical setting. METHODS: Prospective clinical and autoantibody evaluations in a cohort of 219 consecutive patients with new-onset focal epilepsy. RESULTS: 10.5% (23/219) of people with new-onset focal epilepsy had detectable serum autoantibodies to known or novel cell surface antigenic targets. 9/23 with autoantibodies were diagnosed with encephalitis, by contrast to 0/196 without autoantibodies (p<0.0001). Multivariate analysis identified six features which predicted autoantibody positivity (area under the curve=0.83): age ≥54 years, ictal piloerection, lowered self-reported mood, reduced attention, MRI limbic system changes and the absence of conventional epilepsy risk factors. 11/14 (79%) patients with detectable autoantibodies, but without encephalitis, showed excellent long-term outcomes (modified Rankin Score=0) despite no immunotherapy. These outcomes were superior to those of immunotherapy-treated patients with confirmed autoantibody-mediated encephalitis (p<0.05). CONCLUSIONS: Seizure semiology, cognitive and mood phenotypes, alongside inflammatory investigation findings, aid the identification of surface autoantibodies among unselected people with new-onset focal epilepsy. The excellent immunotherapy-independent outcomes of autoantibody-positive patients without encephalitis suggests immunotherapy administration should be guided by clinical features of encephalitis, rather than autoantibody positivity. Our findings suggest that, in this cohort, immunotherapy-responsive seizure syndromes with autoantibodies largely fall under the umbrella of autoimmune encephalitis.


Asunto(s)
Autoanticuerpos/sangre , Epilepsias Parciales/sangre , Epilepsias Parciales/inmunología , Inmunoterapia , Proteínas del Tejido Nervioso/inmunología , Adolescente , Adulto , Anciano , Estudios de Cohortes , Encefalitis/sangre , Encefalitis/etiología , Epilepsias Parciales/terapia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Curva ROC , Adulto Joven
12.
RNA Biol ; 17(12): 1741-1753, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32597303

RESUMEN

RNA-seq is the standard method for profiling gene expression in many biological systems. Due to the wide dynamic range and complex nature of the transcriptome, RNA-seq provides an incomplete characterization, especially of lowly expressed genes and transcripts. Targeted RNA sequencing (RNA CaptureSeq) focuses sequencing on genes of interest, providing exquisite sensitivity for transcript detection and quantification. However, uses of CaptureSeq have focused on bulk samples and its performance on very small populations of cells is unknown. Here we show CaptureSeq greatly enhances transcriptomic profiling of target genes in ultra-low-input samples and provides equivalent performance to that on bulk samples. We validate the performance of CaptureSeq using multiple probe sets on samples of iPSC-derived cortical neurons. We demonstrate up to 275-fold enrichment for target genes, the detection of 10% additional genes and a greater than 5-fold increase in identified gene isoforms. Analysis of spike-in controls demonstrated CaptureSeq improved both detection sensitivity and expression quantification. Comparison to the CORTECON database of cerebral cortex development revealed CaptureSeq enhanced the identification of sample differentiation stage. CaptureSeq provides sensitive, reliable and quantitative expression measurements on hundreds-to-thousands of target genes from ultra-low-input samples and has the potential to greatly enhance transcriptomic profiling when samples are limiting.


Asunto(s)
Perfilación de la Expresión Génica , Secuenciación de Nucleótidos de Alto Rendimiento , Análisis de Secuencia de ARN , Transcriptoma , Diferenciación Celular/genética , Biología Computacional/métodos , Perfilación de la Expresión Génica/métodos , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Neuronas/citología , Neuronas/metabolismo , Análisis de Secuencia de ARN/métodos , Factores de Transcripción/metabolismo
13.
Brain ; 142(12): 3852-3867, 2019 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-31742594

RESUMEN

The two-pore potassium channel, TRESK has been implicated in nociception and pain disorders. We have for the first time investigated TRESK function in human nociceptive neurons using induced pluripotent stem cell-based models. Nociceptors from migraine patients with the F139WfsX2 mutation show loss of functional TRESK at the membrane, with a corresponding significant increase in neuronal excitability. Furthermore, using CRISPR-Cas9 engineering to correct the F139WfsX2 mutation, we show a reversal of the heightened neuronal excitability, linking the phenotype to the mutation. In contrast we find no change in excitability in induced pluripotent stem cell derived nociceptors with the C110R mutation and preserved TRESK current; thereby confirming that only the frameshift mutation is associated with loss of function and a migraine relevant cellular phenotype. We then demonstrate the importance of TRESK to pain states by showing that the TRESK activator, cloxyquin, can reduce the spontaneous firing of nociceptors in an in vitro human pain model. Using the chronic nitroglycerine rodent migraine model, we demonstrate that mice lacking TRESK develop exaggerated nitroglycerine-induced mechanical and thermal hyperalgesia, and furthermore, show that cloxyquin conversely is able to prevent sensitization. Collectively, our findings provide evidence for a role of TRESK in migraine pathogenesis and its suitability as a therapeutic target.


Asunto(s)
Mutación con Pérdida de Función , Trastornos Migrañosos/genética , Nocicepción/fisiología , Nociceptores/metabolismo , Canales de Potasio/genética , Animales , Sistemas CRISPR-Cas , Modelos Animales de Enfermedad , Humanos , Células Madre Pluripotentes Inducidas/metabolismo , Ratones , Trastornos Migrañosos/inducido químicamente , Trastornos Migrañosos/metabolismo , Nitroglicerina , Dimensión del Dolor , Técnicas de Placa-Clamp , Canales de Potasio/metabolismo
14.
Hum Mol Genet ; 26(1): 79-89, 2017 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-27798116

RESUMEN

Dense genotyping approaches have revealed much about the genetic architecture both of gene expression and disease susceptibility. However, assigning causality to genetic variants associated with a transcriptomic or phenotypic trait presents a far greater challenge. The development of epigenomic resources by ENCODE, the Epigenomic Roadmap and others has led to strategies that seek to infer the likely functional variants underlying these genome-wide association signals. It is known, for example, that such variants tend to be located within areas of open chromatin, as detected by techniques such as DNase-seq and FAIRE-seq. We aimed to assess what proportion of variants associated with phenotypic or transcriptomic traits in the human brain are located within transcription factor binding sites. The bioinformatic tools, Wellington and HINT, were used to infer transcription factor footprints from existing DNase-seq data derived from central nervous system tissues with high spatial resolution. This dataset was then employed to assess the likely contribution of altered transcription factor binding to both expression quantitative trait loci (eQTL) and genome-wide association study (GWAS) signals. Surprisingly, we show that most haplotypes associated with GWAS or eQTL phenotypes are located outside of DNase-seq footprints. This could imply that DNase-seq footprinting is too insensitive an approach to identify a large proportion of true transcription factor binding sites. Importantly, this suggests that prioritising variants for genome engineering studies to establish causality will continue to be frustrated by an inability of footprinting to identify the causative variant within a haplotype.


Asunto(s)
Encefalopatías/patología , Encéfalo/patología , Huella de ADN/métodos , Desoxirribonucleasa I/metabolismo , Haplotipos/genética , Sitios de Carácter Cuantitativo/genética , Factores de Transcripción/metabolismo , Sitios de Unión , Encéfalo/metabolismo , Encefalopatías/genética , Encefalopatías/metabolismo , Cromatina/metabolismo , Inmunoprecipitación de Cromatina , Biología Computacional/métodos , Bases de Datos Factuales , Regulación de la Expresión Génica , Variación Genética/genética , Genoma Humano , Estudio de Asociación del Genoma Completo , Genotipo , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Anotación de Secuencia Molecular , Fenotipo , Unión Proteica , Análisis de Secuencia de ADN/métodos
15.
Hum Mol Genet ; 25(5): 989-1000, 2016 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-26740550

RESUMEN

Induced pluripotent stem cell (iPSC)-derived cortical neurons potentially present a powerful new model to understand corticogenesis and neurological disease. Previous work has established that differentiation protocols can produce cortical neurons, but little has been done to characterize these at cellular resolution. In particular, it is unclear to what extent in vitro two-dimensional, relatively disordered culture conditions recapitulate the development of in vivo cortical layer identity. Single-cell multiplex reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) was used to interrogate the expression of genes previously implicated in cortical layer or phenotypic identity in individual cells. Totally, 93.6% of single cells derived from iPSCs expressed genes indicative of neuronal identity. High proportions of single neurons derived from iPSCs expressed glutamatergic receptors and synaptic genes. And, 68.4% of iPSC-derived neurons expressing at least one layer marker could be assigned to a laminar identity using canonical cortical layer marker genes. We compared single-cell RNA-seq of our iPSC-derived neurons to available single-cell RNA-seq data from human fetal and adult brain and found that iPSC-derived cortical neurons closely resembled primary fetal brain cells. Unexpectedly, a subpopulation of iPSC-derived neurons co-expressed canonical fetal deep and upper cortical layer markers. However, this appeared to be concordant with data from primary cells. Our results therefore provide reassurance that iPSC-derived cortical neurons are highly similar to primary cortical neurons at the level of single cells but suggest that current layer markers, although effective, may not be able to disambiguate cortical layer identity in all cells.


Asunto(s)
Corteza Cerebral/metabolismo , Células Madre Pluripotentes Inducidas/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Neurogénesis/genética , Neuronas/metabolismo , Transcriptoma , Adulto , Anciano , Biomarcadores/metabolismo , Diferenciación Celular , Línea Celular , Corteza Cerebral/citología , Femenino , Feto , Fibroblastos/citología , Fibroblastos/metabolismo , Perfilación de la Expresión Génica , Regulación del Desarrollo de la Expresión Génica , Humanos , Células Madre Pluripotentes Inducidas/citología , Proteínas del Tejido Nervioso/genética , Neuronas/citología , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores de Glutamato/genética , Receptores de Glutamato/metabolismo , Análisis de Secuencia de ARN , Análisis de la Célula Individual
17.
Hum Mol Genet ; 23(4): 942-8, 2014 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-24092328

RESUMEN

Genome-wide association studies (GWASs) have shown that approximately 60 genetic variants influence the risk of developing multiple sclerosis (MS). Our aim was to identify the cell types in which these variants are active. We used available data on MS-associated single nucleotide polymorphisms (SNPs) and deoxyribonuclease I hypersensitive sites (DHSs) from 112 different cell types. Genomic intervals were tested for overlap using the Genomic Hyperbrowser. The expression profile of the genes located nearby MS-associated SNPs was assessed using the software GRAIL (Gene Relationships Across Implicated Loci). Genomic regions associated with MS were significantly enriched for a number of immune DHSs and in particular T helper (Th) 1, Th17, CD8+ cytotoxic T cells, CD19+ B cells and CD56+ natural killer (NK) cells (enrichment = 2.34, 2.19, 2.27, 2.05 and 1.95, respectively; P < 0.0001 for all of them). Similar results were obtained when genomic regions with suggestive association with MS and additional immune-mediated traits were investigated. Several new candidate MS-associated genes located within regions of suggestive association were identified by GRAIL (CARD11, FCRL2, CHST12, SYK, TCF7, SOCS1, NFKBIZ and NPAS1). Genetic data indicate that Th1, Th17, cytotoxic T, B and NK cells play a prominent role in the etiology of MS. Regions with confirmed and suggestive association have a similar immunological profile, indicating that many SNPs truly influencing the risk of MS actually fail to reach genome-wide significance. Finally, similar cell types are involved in the etiology of other immune-mediated diseases.


Asunto(s)
Esclerosis Múltiple/genética , Desoxirribonucleasas/química , Epistasis Genética , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Células Hep G2 , Humanos , Polimorfismo de Nucleótido Simple
19.
BMC Med Educ ; 14: 225, 2014 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-25335431

RESUMEN

BACKGROUND: Medical students perceive neurology to be a difficult subject, a phenomenon described as "neurophobia". Studies investigating student attitudes towards neurology have so far been limited by small sample sizes as a consequence of being conducted within a single medical school or region. We aimed to conduct the first national survey of the perception of neurology among UK medical students. METHODS: A 24 question online survey was designed and distributed in the form of a web-link to all UK medical schools. Responses were collected for 10 weeks with reminders sent at 3 and 6 weeks. A prize-draw of £300 was offered upon completion of the survey. RESULTS: 2877 medical students from 25 of 31 medical schools responded. Students found neurology to be significantly more difficult than other specialties and were least comfortable drawing up a neurological differential diagnosis compared to other specialties (p < 0.0001 for neurology vs. each of the other specialties). Neuroanatomy was regarded as the most important factor contributing to neurology being perceived as difficult. CONCLUSIONS: The findings of the first national survey addressing this issue are consistent with previous research. The perception of neurology remains unchanged, in contrast to the rapidly changing demands of neurological care in an ageing population. Neurological examination and formulating a differential diagnosis are important skills in any medical specialty, and combatting "neurophobia" in medical students is therefore essential.


Asunto(s)
Selección de Profesión , Educación de Pregrado en Medicina/estadística & datos numéricos , Neurología/educación , Estudiantes de Medicina/estadística & datos numéricos , Encuestas y Cuestionarios , Adulto , Estudios Transversales , Educación de Pregrado en Medicina/métodos , Evaluación Educacional , Femenino , Humanos , Masculino , Percepción , Vigilancia de la Población , Facultades de Medicina/estadística & datos numéricos , Estudiantes de Medicina/psicología , Reino Unido
20.
Ann Clin Transl Neurol ; 11(4): 1053-1058, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38303486

RESUMEN

Patient-reported quality-of-life (QoL) and carer impacts are not reported after leucine-rich glioma-inactivated 1-antibody encephalitis (LGI1-Ab-E). From 60 patients, 85% (51 out of 60) showed one abnormal score across QoL assessments and 11 multimodal validated questionnaires. Compared to the premorbid state, QoL significantly deteriorated (p < 0.001) and, at a median of 41 months, fatigue was its most important predictor (p = 0.025). In total, 51% (26 out of 51) of carers reported significant burden. An abbreviated five-item battery explained most variance in QoL. Wide-ranging impacts post-LGI1-Ab-E include decreased QoL and high caregiver strain. We identify a rapid method to capture QoL in routine clinic or clinical trial settings.


Asunto(s)
Encefalitis , Glioma , Humanos , Leucina , Calidad de Vida , Péptidos y Proteínas de Señalización Intracelular , Autoanticuerpos , Fatiga/etiología
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