RESUMEN
TREX1/DNASE III, the most abundant 3'-5' DNA exonuclease in mammalian cells, is tail-anchored on the endoplasmic reticulum (ER). Mutations at the N-terminus affecting TREX1 DNase activity are associated with autoimmune and inflammatory conditions such as Aicardi-Goutières syndrome (AGS). Mutations in the C-terminus of TREX1 cause loss of localization to the ER and dysregulation of oligosaccharyltransferase (OST) activity, and are associated with retinal vasculopathy with cerebral leukodystrophy (RVCL) and in some cases with systemic lupus erythematosus (SLE). Here we investigate mice with conditional expression of the most common RVCL mutation, V235fs, and another mouse expressing a conditional C-terminal mutation, D272fs, associated with a case of human SLE. Mice homozygous for either mutant allele express the encoded human TREX1 truncations without endogenous mouse TREX1, and both remain DNase active in tissues. The two mouse strains are similar phenotypically without major signs of retinal, cerebral or renal disease but exhibit striking elevations of autoantibodies in the serum. The broad range of autoantibodies is primarily against non-nuclear antigens, in sharp contrast to the predominantly DNA-related autoantibodies produced by a TREX1-D18N mouse that specifically lacks DNase activity. We also found that treatment with an OST inhibitor, aclacinomycin, rapidly suppressed autoantibody production in the TREX1 frame-shift mutant mice. Together, our study presents two new mouse models based on TREX1 frame-shift mutations with a unique set of serologic autoimmune-like phenotypes.
Asunto(s)
Autoinmunidad/genética , Autoinmunidad/inmunología , Exodesoxirribonucleasas/genética , Mutación del Sistema de Lectura , Fosfoproteínas/genética , Aclarubicina/análogos & derivados , Aclarubicina/farmacología , Sustitución de Aminoácidos , Animales , Apoptosis/genética , Apoptosis/inmunología , Autoanticuerpos/inmunología , Autoinmunidad/efectos de los fármacos , Linfocitos B/inmunología , Linfocitos B/metabolismo , Activación Enzimática , Exodesoxirribonucleasas/química , Exodesoxirribonucleasas/metabolismo , Expresión Génica , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Humanos , Ratones , Ratones Transgénicos , Fenotipo , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Retina/inmunología , Retina/metabolismo , Retina/patología , Timocitos/inmunología , Timocitos/metabolismo , TranscriptomaRESUMEN
Autosomal dominant retinal vasculopathy with cerebral leukodystrophy is a microvascular endotheliopathy with middle-age onset. In nine families, we identified heterozygous C-terminal frameshift mutations in TREX1, which encodes a 3'-5' exonuclease. These truncated proteins retain exonuclease activity but lose normal perinuclear localization. These data have implications for the maintenance of vascular integrity in the degenerative cerebral microangiopathies leading to stroke and dementias.
Asunto(s)
Encefalopatías/genética , Exodesoxirribonucleasas/genética , Mutación , Fosfoproteínas/genética , Enfermedades de la Retina/genética , Secuencia de Aminoácidos , Encefalopatías/enzimología , Línea Celular , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Exodesoxirribonucleasas/química , Exodesoxirribonucleasas/metabolismo , Genes Dominantes , Predisposición Genética a la Enfermedad , Humanos , Proteínas Luminiscentes/genética , Proteínas Luminiscentes/metabolismo , Microscopía Confocal , Datos de Secuencia Molecular , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Enfermedades de la Retina/enzimología , Homología de Secuencia de Aminoácido , TransfecciónAsunto(s)
Asma/genética , Cromosomas Humanos Par 17/genética , Predisposición Genética a la Enfermedad/genética , Proteínas de la Membrana/genética , Proteínas de Neoplasias/genética , Islas de CpG , Metilación de ADN , Regulación de la Expresión Génica/genética , Genotipo , Humanos , Polimorfismo de Nucleótido Simple , Sitios de Carácter CuantitativoAsunto(s)
CADASIL/diagnóstico por imagen , CADASIL/epidemiología , Vasculitis Retiniana/diagnóstico por imagen , Vasculitis Retiniana/epidemiología , Adulto , CADASIL/genética , Femenino , Humanos , Leucoencefalopatías/diagnóstico por imagen , Leucoencefalopatías/epidemiología , Leucoencefalopatías/genética , Masculino , Persona de Mediana Edad , Vasculitis Retiniana/genéticaRESUMEN
The molecular and clinical features of a complex disease can be influenced by other diseases affecting the same individual. Understanding disease-disease interactions is therefore crucial for revealing shared molecular mechanisms among diseases and designing effective treatments. Here we introduce Flow Centrality (FC), a network-based approach to identify the genes mediating the interaction between two diseases in a protein-protein interaction network. We focus on asthma and COPD, two chronic respiratory diseases that have been long hypothesized to share common genetic determinants and mechanisms. We show that FC highlights potential mediator genes between the two diseases, and observe similar outcomes when applying FC to 66 additional pairs of related diseases. Further, we perform in vitro perturbation experiments on a widely replicated asthma gene, GSDMB, showing that FC identifies candidate mediators of the interactions between GSDMB and COPD-associated genes. Our results indicate that FC predicts promising gene candidates for further study of disease-disease interactions.
Asunto(s)
Asma/genética , Predisposición Genética a la Enfermedad/genética , Mapas de Interacción de Proteínas/genética , Enfermedad Pulmonar Obstructiva Crónica/genética , Asma/complicaciones , Asma/metabolismo , Línea Celular , Biología Computacional/métodos , Perfilación de la Expresión Génica , Humanos , Proteínas de Neoplasias/genética , Enfermedad Pulmonar Obstructiva Crónica/complicaciones , Enfermedad Pulmonar Obstructiva Crónica/metabolismo , Reproducibilidad de los ResultadosRESUMEN
BACKGROUND: Mutations in the three-prime repair exonuclease 1 (TREX1) gene have been associated with neurological diseases, including Retinal Vasculopathy with Cerebral Leukoencephalopathy (RVCL). However, the endogenous expression of TREX1 in human brain has not been studied. METHODS: We produced a rabbit polyclonal antibody (pAb) to TREX1 to characterize TREX1 by Western blotting (WB) of cell lysates from normal controls and subjects carrying an RVCL frame-shift mutation. Dual staining was performed to determine cell types expressing TREX1 in human brain tissue. TREX1 distribution in human brain was further evaluated by immunohistochemical analyses of formalin-fixed, paraffin-embedded samples from normal controls and patients with RVCL and ischemic stroke. RESULTS: After validating the specificity of our anti-TREX1 rabbit pAb, WB analysis was utilized to detect the endogenous wild-type and frame-shift mutant of TREX1 in cell lysates. Dual staining in human brain tissues from patients with RVCL and normal controls localized TREX1 to a subset of microglia and macrophages. Quantification of immunohistochemical staining of the cerebral cortex revealed that TREX1+ microglia were primarily in the gray matter of normal controls (22.7 ± 5.1% and 5.5 ± 1.9% of Iba1+ microglia in gray and white matter, respectively) and commonly in association with the microvasculature. In contrast, in subjects with RVCL, the TREX1+ microglia were predominantly located in the white matter of normal appearing cerebral cortex (11.8 ± 3.1% and 38.9 ± 5.8% of Iba1+ microglia in gray and white matter, respectively). The number of TREX1+ microglia was increased in ischemic brain lesions in central nervous system of RVCL and stroke patients. CONCLUSIONS: TREX1 is expressed by a subset of microglia in normal human brain, often in close proximity to the microvasculature, and increases in the setting of ischemic lesions. These findings suggest a role for TREX1+ microglia in vessel homeostasis and response to ischemic injury.
Asunto(s)
Isquemia Encefálica/metabolismo , Isquemia Encefálica/patología , Encéfalo/metabolismo , Exodesoxirribonucleasas/metabolismo , Exodesoxirribonucleasas/fisiología , Microglía/metabolismo , Fosfoproteínas/metabolismo , Fosfoproteínas/fisiología , Anciano , Animales , Anticuerpos/metabolismo , Encéfalo/patología , Exodesoxirribonucleasas/genética , Femenino , Mutación del Sistema de Lectura , Células HEK293 , Células HeLa , Enfermedades Desmielinizantes del Sistema Nervioso Central Hereditarias/genética , Enfermedades Desmielinizantes del Sistema Nervioso Central Hereditarias/patología , Homeostasis/fisiología , Humanos , Macrófagos/metabolismo , Masculino , Persona de Mediana Edad , Fosfoproteínas/genética , Conejos/inmunología , Enfermedades de la Retina/genética , Enfermedades de la Retina/patología , Enfermedades Vasculares/genética , Enfermedades Vasculares/patologíaRESUMEN
Cerebroretinal vasculopathy (CRV) and the related diseases hereditary endotheliopathy with retinopathy, neuropathy, and stroke (HERNS), hereditary vascular retinopathy (HVR) and hereditary systemic angiopathy (HSA) [subsequently combined as retinovasculopathy and cerebral leukodystrophy (RVCL)] are devastating autosomal-dominant disorders of early to middle-age onset presenting with a core constellation of neurologic and ophthalmologic findings. This family of diseases is linked by specific mutations targeting a core region of a gene. Frameshift mutations in the carboxyl-terminus of three prime exonuclease-1 (TREX1), the major mammalian 3' to 5' DNA exonuclease on chromosome 3p21.1-p21.3, result in a systemic vasculopathy that follows an approximately 5-year course leading to death secondary to progressive neurologic decline, with sometimes a more protracted course in HERNS. Neuropathological features include a fibrinoid vascular necrosis or thickened hyalinized vessels associated with white matter ischemia, necrosis and often striking dystrophic calcifications. Ultrastructural studies of the vessel walls often demonstrate unusual multilaminated basement membranes.
Asunto(s)
Exodesoxirribonucleasas/genética , Enfermedades Desmielinizantes del Sistema Nervioso Central Hereditarias/genética , Enfermedades Desmielinizantes del Sistema Nervioso Central Hereditarias/patología , Fosfoproteínas/genética , Enfermedades de la Retina/genética , Enfermedades de la Retina/patología , Enfermedades Vasculares/genética , Enfermedades Vasculares/patología , Encéfalo/irrigación sanguínea , Encéfalo/ultraestructura , Mutación del Sistema de Lectura , Humanos , Riñón/ultraestructuraRESUMEN
Aicardi-Goutières syndrome (AGS), Systemic Lupus Erythematosus (SLE), Familial Chilblain Lupus (FCL) and Retinal Vasculopathy and Cerebral Leukodystrophy (RVCL) {a new term encompassing three independently described conditions with a common etiology--Cerebroretinal Vasculopathy (CRV), Hereditary Vascular Retinopathy (HVR) and Hereditary Endotheliopathy, Retinopathy and Nephropathy (HERNS)}--have previously been regarded as distinct entities. However, recent genetic analysis has demonstrated that each of these diseases maps to chromosome 3p21 and can be caused by mutations in TREX1, the major human 3'-5' exonuclease. In this review, we discuss the putative functions of TREX1 in relationship to the clinical, genetic and functional characteristics of each of these conditions.