RESUMEN
The mechanisms underlying the selective regional vulnerability to neurodegeneration in Huntington's disease (HD) have not been fully defined. To explore the role of astrocytes in this phenomenon, we used single-nucleus and bulk RNAseq, lipidomics, HTT gene CAG repeat-length measurements, and multiplexed immunofluorescence on HD and control post-mortem brains. We identified genes that correlated with CAG repeat length, which were enriched in astrocyte genes, and lipidomic signatures that implicated poly-unsaturated fatty acids in sensitizing neurons to cell death. Because astrocytes play essential roles in lipid metabolism, we explored the heterogeneity of astrocytic states in both protoplasmic and fibrous-like (CD44+) astrocytes. Significantly, one protoplasmic astrocyte state showed high levels of metallothioneins and was correlated with the selective vulnerability of distinct striatal neuronal populations. When modeled in vitro, this state improved the viability of HD-patient-derived spiny projection neurons. Our findings uncover key roles of astrocytic states in protecting against neurodegeneration in HD.
Asunto(s)
Astrocitos , Enfermedad de Huntington , Neuronas , Enfermedad de Huntington/metabolismo , Enfermedad de Huntington/genética , Enfermedad de Huntington/patología , Astrocitos/metabolismo , Astrocitos/patología , Humanos , Neuronas/metabolismo , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Masculino , Femenino , Lipidómica/métodos , Persona de Mediana Edad , Metalotioneína/metabolismo , Metalotioneína/genética , Encéfalo/metabolismo , Encéfalo/patología , Metabolismo de los Lípidos , Anciano , MultiómicaRESUMEN
Understanding the normal function of the Huntingtin (HTT) protein is of significance in the design and implementation of therapeutic strategies for Huntington's disease (HD). Expansion of the CAG repeat in the HTT gene, encoding an expanded polyglutamine (polyQ) repeat within the HTT protein, causes HD and may compromise HTT's normal activity contributing to HD pathology. Here, we investigated the previously defined role of HTT in autophagy specifically through studying HTT's association with ubiquitin. We find that HTT interacts directly with ubiquitin in vitro. Tandem affinity purification was used to identify ubiquitinated and ubiquitin-associated proteins that copurify with a HTT N-terminal fragment under basal conditions. Copurification is enhanced by HTT polyQ expansion and reduced by mimicking HTT serine 421 phosphorylation. The identified HTT-interacting proteins include RNA-binding proteins (RBPs) involved in mRNA translation, proteins enriched in stress granules, the nuclear proteome, the defective ribosomal products (DRiPs) proteome and the brain-derived autophagosomal proteome. To determine whether the proteins interacting with HTT are autophagic targets, HTT knockout (KO) cells and immunoprecipitation of lysosomes were used to investigate autophagy in the absence of HTT. HTT KO was associated with reduced abundance of mitochondrial proteins in the lysosome, indicating a potential compromise in basal mitophagy, and increased lysosomal abundance of RBPs which may result from compensatory up-regulation of starvation-induced macroautophagy. We suggest HTT is critical for appropriate basal clearance of mitochondrial proteins and RBPs, hence reduced HTT proteostatic function with mutation may contribute to the neuropathology of HD.
Asunto(s)
Proteína Huntingtina , Lisosomas , Mitocondrias , Proteínas de Unión al ARN , Ubiquitina , Proteína Huntingtina/metabolismo , Proteína Huntingtina/genética , Lisosomas/metabolismo , Proteínas de Unión al ARN/metabolismo , Proteínas de Unión al ARN/genética , Humanos , Ubiquitina/metabolismo , Mitocondrias/metabolismo , Autofagia , Animales , Proteínas Mitocondriales/metabolismo , Proteínas Mitocondriales/genética , Ratones , Unión Proteica , Enfermedad de Huntington/metabolismo , Enfermedad de Huntington/genética , Enfermedad de Huntington/patología , Péptidos/metabolismoRESUMEN
CalDAG-GEFI (CDGI) is a protein highly enriched in the striatum, particularly in the principal spiny projection neurons (SPNs). CDGI is strongly down-regulated in two hyperkinetic conditions related to striatal dysfunction: Huntington's disease and levodopa-induced dyskinesia in Parkinson's disease. We demonstrate that genetic deletion of CDGI in mice disrupts dendritic, but not somatic, M1 muscarinic receptors (M1Rs) signaling in indirect pathway SPNs. Loss of CDGI reduced temporal integration of excitatory postsynaptic potentials at dendritic glutamatergic synapses and impaired the induction of activity-dependent long-term potentiation. CDGI deletion selectively increased psychostimulant-induced repetitive behaviors, disrupted sequence learning, and eliminated M1R blockade of cocaine self-administration. These findings place CDGI as a major, but previously unrecognized, mediator of cholinergic signaling in the striatum. The effects of CDGI deletion on the self-administration of drugs of abuse and its marked alterations in hyperkinetic extrapyramidal disorders highlight CDGI's therapeutic potential.
Asunto(s)
Dendritas , Factores de Intercambio de Guanina Nucleótido/genética , Neostriado/fisiopatología , Plasticidad Neuronal , Sistema Nervioso Parasimpático/fisiopatología , Sinapsis , Animales , Enfermedades de los Ganglios Basales/genética , Enfermedades de los Ganglios Basales/fisiopatología , Enfermedades de los Ganglios Basales/psicología , Estimulantes del Sistema Nervioso Central/farmacología , Potenciales Postsinápticos Excitadores/genética , Hipercinesia/genética , Hipercinesia/psicología , Potenciación a Largo Plazo , Masculino , Ratones , Ratones Noqueados , Actividad Motora , Polimorfismo de Nucleótido Simple , Receptor Muscarínico M1/genética , Receptor Muscarínico M1/fisiología , Trastornos Relacionados con Sustancias/genética , Trastornos Relacionados con Sustancias/fisiopatología , Trastornos Relacionados con Sustancias/psicologíaRESUMEN
Brain metastases are refractory to therapies that control systemic disease in patients with human epidermal growth factor receptor 2 (HER2+) breast cancer, and the brain microenvironment contributes to this therapy resistance. Nutrient availability can vary across tissues, therefore metabolic adaptations required for brain metastatic breast cancer growth may introduce liabilities that can be exploited for therapy. Here, we assessed how metabolism differs between breast tumors in brain versus extracranial sites and found that fatty acid synthesis is elevated in breast tumors growing in brain. We determine that this phenotype is an adaptation to decreased lipid availability in brain relative to other tissues, resulting in a site-specific dependency on fatty acid synthesis for breast tumors growing at this site. Genetic or pharmacological inhibition of fatty acid synthase (FASN) reduces HER2+ breast tumor growth in the brain, demonstrating that differences in nutrient availability across metastatic sites can result in targetable metabolic dependencies.
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Neoplasias Encefálicas , Neoplasias de la Mama , Neoplasias Encefálicas/metabolismo , Neoplasias de la Mama/tratamiento farmacológico , Ácido Graso Sintasas/genética , Ácidos Grasos/uso terapéutico , Femenino , Humanos , Microambiente TumoralRESUMEN
Disruptive or excessive repetitive motor patterns (stereotypies) are cardinal symptoms in numerous neuropsychiatric disorders. Stereotypies are also evoked by psychomotor stimulants such as amphetamine. The acquisition of motor sequences is paralleled by changes in activity patterns in the striatum, and stereotypies have been linked to abnormal plasticity in these reinforcement-related circuits. Here, we designed experiments in mice to identify transcriptomic changes that underlie striatal plasticity occurring alongside the development of drug-induced stereotypic behavior. We identified three schedules of amphetamine treatment inducing different degrees of stereotypy and used bulk RNAseq to compare striatal gene expression changes among groups of mice treated with the different drug-dose schedules and vehicle-treated, cage-mate controls. Mice were identified as naïve, sensitized, or tolerant to drug-induced stereotypy. All drug-treated groups exhibited expression changes in genes that encode members of the extracellular signal-regulated kinase (ERK) cascades known to regulate psychomotor stimulant responses. In the sensitized group with the most prolonged stereotypy, we found dysregulation of 20 genes that were not changed in other groups. Gene set enrichment analysis indicated highly significant overlap with genes regulated by neuregulin 1 (Nrg1). Nrg1 is known to be a schizophrenia and autism susceptibility gene that encodes a ligand for Erb-B receptors, which are involved in neuronal migration, myelination, and cell survival, including that of dopamine-containing neurons. Stimulant abuse is a risk factor for schizophrenia onset, and these two disorders share behavioral stereotypy phenotypes. Our results raise the possibility that drug-induced sensitization of the Nrg1 signaling pathway might underlie these links.
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Preparaciones Farmacéuticas , Transcriptoma , Anfetamina , Animales , Cuerpo Estriado , Ratones , Conducta EstereotipadaRESUMEN
Epstein-Barr virus (EBV) is a ubiquitous human γ-herpesvirus that establishes life-long infection and increases the risk for the development of several cancers and autoimmune diseases. The mechanisms by which chronic EBV infection leads to subsequent disease remain incompletely understood. Lytic reactivation plays a central role in the development of EBV-driven cancers and may contribute to other EBV-associated diseases. Thus, the clinical use of antivirals as suppressive therapy for EBV lytic reactivation may aid efforts aimed at disease prevention. Current antivirals for EBV have shown limited clinical utility due to low potency or high toxicity, leaving open the need for potent antivirals suitable for long-term prophylaxis. In the present study, we show that tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF), drugs with excellent safety profiles used clinically for HIV prevention, inhibit EBV lytic DNA replication, with respective IC50 values of 0.30 µM and 84 nM. In a cell-based assay, TAF was 35- and 24-fold and TDF was 10- and 7-fold more potent than acyclovir and penciclovir, respectively, and TAF was also twice as potent as ganciclovir. The active metabolite of tenofovir prodrugs, tenofovir-diphosphate, inhibited the incorporation of dATP into a primed DNA template by the EBV DNA polymerase in vitro. In contrast to acyclovir, treatment of cells during latency for 24 h with TAF still inhibited EBV lytic DNA replication at 72 h after drug was removed. Our results suggest that tenofovir prodrugs may be particularly effective as inhibitors of EBV lytic reactivation, and that clinical studies to address critical questions about disease prevention are warranted.
Asunto(s)
Antivirales/farmacología , Replicación del ADN/efectos de los fármacos , Infecciones por Virus de Epstein-Barr/virología , Herpesvirus Humano 4/efectos de los fármacos , Inhibidores de la Síntesis del Ácido Nucleico/farmacología , Tenofovir/farmacología , Proteínas Virales/antagonistas & inhibidores , ADN Viral/genética , ADN Viral/metabolismo , ADN Polimerasa Dirigida por ADN/genética , ADN Polimerasa Dirigida por ADN/metabolismo , Herpesvirus Humano 4/enzimología , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/fisiología , Humanos , Profármacos/farmacología , Proteínas Virales/genética , Proteínas Virales/metabolismo , Replicación Viral/efectos de los fármacosRESUMEN
Huntington's disease (HD) is a chronic neurodegenerative disorder characterized by a late clinical onset despite ubiquitous expression of the mutant Huntingtin gene (HTT) from birth. Transcriptional dysregulation is a pivotal feature of HD. Yet, the genes that are altered in the prodromal period and their regulators, which present opportunities for therapeutic intervention, remain to be elucidated. Using transcriptional and chromatin profiling, we found aberrant transcription and changes in histone H3K27acetylation in the striatum of R6/1 mice during the presymptomatic disease stages. Integrating these data, we identified the Elk-1 transcription factor as a candidate regulator of prodromal changes in HD. Exogenous expression of Elk-1 exerted beneficial effects in a primary striatal cell culture model of HD, and adeno-associated virus-mediated Elk-1 overexpression alleviated transcriptional dysregulation in R6/1 mice. Collectively, our work demonstrates that aberrant gene expression precedes overt disease onset in HD, identifies the Elk-1 transcription factor as a key regulator linked to early epigenetic and transcriptional changes in HD, and presents evidence for Elk-1 as a target for alleviating molecular pathology in HD.
Asunto(s)
Epigenómica , Enfermedad de Huntington/genética , Proteína Elk-1 con Dominio ets/genética , Proteína Elk-1 con Dominio ets/metabolismo , Animales , Cuerpo Estriado/metabolismo , Dependovirus , Modelos Animales de Enfermedad , Histonas/metabolismo , Proteína Huntingtina/genética , Enfermedad de Huntington/tratamiento farmacológico , Ratones , Ratones Transgénicos , Neuronas/metabolismo , Proteínas Nucleares/metabolismoRESUMEN
Neuroinflammation is an important contributor to neuronal pathology and death in neurodegenerative diseases and neuronal injury. Therapeutic interventions blocking the activity of the inflammatory kinase IKKß, a key regulator of neuroinflammatory pathways, is protective in several animal models of neurodegenerative disease and neuronal injury. In Huntington's disease (HD), however, significant questions exist as to the impact of blocking or diminishing the activity of IKKß on HD pathology given its potential role in Huntingtin (HTT) degradation. In cell culture, IKKß phosphorylates HTT serine (S) 13 and activates HTT degradation, a process that becomes impaired with polyQ expansion. To investigate the in vivo relationship of IKKß to HTT S13 phosphorylation and HD progression, we crossed conditional tamoxifen-inducible IKKß knockout mice with R6/1 HD mice. Behavioral assays in these mice showed a significant worsening of HD pathological phenotypes. The increased behavioral pathology correlated with reduced levels of endogenous mouse full-length phospho-S13 HTT, supporting the importance of IKKß in the phosphorylation of HTT S13 in vivo. Notably, many striatal autophagy genes were up-regulated in HD vs. control mice; however, IKKß knockout partially reduced this up-regulation in HD, increased striatal neurodegeneration, and enhanced an activated microglial response. We propose that IKKß is protective in striatal neurons early in HD progression via phosphorylation of HTT S13. As IKKß is also required for up-regulation of some autophagy genes and HTT is a scaffold for selective autophagy, IKKß may influence autophagy through multiple mechanisms to maintain healthy striatal function, thereby reducing neuronal degeneration to slow HD onset.
Asunto(s)
Enfermedad de Huntington , Quinasa I-kappa B , Animales , Autofagia/genética , Cuerpo Estriado/citología , Cuerpo Estriado/patología , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Enfermedad de Huntington/metabolismo , Enfermedad de Huntington/patología , Quinasa I-kappa B/genética , Quinasa I-kappa B/metabolismo , Masculino , Ratones , Ratones Noqueados , Microglía/citología , Microglía/patología , Fosforilación/genéticaRESUMEN
Skeletal muscle has emerged as a critical, disease-relevant target tissue in spinal and bulbar muscular atrophy, a degenerative disorder of the neuromuscular system caused by a CAG/polyglutamine (polyQ) expansion in the androgen receptor (AR) gene. Here, we used RNA-sequencing (RNA-Seq) to identify pathways that are disrupted in diseased muscle using AR113Q knockin mice. This analysis unexpectedly identified substantially diminished expression of numerous ubiquitin/proteasome pathway genes in AR113Q muscle, encoding approximately 30% of proteasome subunits and 20% of E2 ubiquitin conjugases. These changes were age, hormone, and glutamine length dependent and arose due to a toxic gain of function conferred by the mutation. Moreover, altered gene expression was associated with decreased levels of the proteasome transcription factor NRF1 and its activator DDI2 and resulted in diminished proteasome activity. Ubiquitinated ADRM1 was detected in AR113Q muscle, indicating the occurrence of stalled proteasomes in mutant mice. Finally, diminished expression of Drosophila orthologues of NRF1 or ADRM1 promoted the accumulation of polyQ AR protein and increased toxicity. Collectively, these data indicate that AR113Q muscle develops progressive proteasome dysfunction that leads to the impairment of quality control and the accumulation of polyQ AR protein, key features that contribute to the age-dependent onset and progression of this disorder.
Asunto(s)
Envejecimiento/metabolismo , Músculo Esquelético/metabolismo , Atrofia Muscular Espinal/metabolismo , Péptidos/metabolismo , Receptores Androgénicos/metabolismo , Expansión de Repetición de Trinucleótido , Envejecimiento/genética , Envejecimiento/patología , Animales , Moléculas de Adhesión Celular/genética , Moléculas de Adhesión Celular/metabolismo , Péptidos y Proteínas de Señalización Intracelular , Masculino , Ratones , Ratones Transgénicos , Músculo Esquelético/patología , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/patología , Factor Nuclear 1 de Respiración/genética , Factor Nuclear 1 de Respiración/metabolismo , Péptidos/genética , Complejo de la Endopetidasa Proteasomal/genética , Complejo de la Endopetidasa Proteasomal/metabolismo , Receptores Androgénicos/genéticaRESUMEN
TDP-43 (encoded by the gene TARDBP) is an RNA binding protein central to the pathogenesis of amyotrophic lateral sclerosis (ALS). However, how TARDBP mutations trigger pathogenesis remains unknown. Here, we use novel mouse mutants carrying point mutations in endogenous Tardbp to dissect TDP-43 function at physiological levels both in vitro and in vivo Interestingly, we find that mutations within the C-terminal domain of TDP-43 lead to a gain of splicing function. Using two different strains, we are able to separate TDP-43 loss- and gain-of-function effects. TDP-43 gain-of-function effects in these mice reveal a novel category of splicing events controlled by TDP-43, referred to as "skiptic" exons, in which skipping of constitutive exons causes changes in gene expression. In vivo, this gain-of-function mutation in endogenous Tardbp causes an adult-onset neuromuscular phenotype accompanied by motor neuron loss and neurodegenerative changes. Furthermore, we have validated the splicing gain-of-function and skiptic exons in ALS patient-derived cells. Our findings provide a novel pathogenic mechanism and highlight how TDP-43 gain of function and loss of function affect RNA processing differently, suggesting they may act at different disease stages.
Asunto(s)
Esclerosis Amiotrófica Lateral/genética , Proteínas de Unión al ADN/genética , Regulación de la Expresión Génica/genética , Proteínas de Unión al ARN/genética , Empalme Alternativo/genética , Esclerosis Amiotrófica Lateral/patología , Animales , Exones/genética , Humanos , Ratones , Neuronas Motoras/metabolismo , Neuronas Motoras/patología , Mutación , Empalme del ARN/genéticaRESUMEN
We present the case of an HIV-negative patient clinically diagnosed with relapsing-remitting MS who achieved significant disease improvement on Combivir (zidovudine/lamivudine). Within months of treatment, the patient reported complete resolution of previously unremitting fatigue and paresthesiae, with simultaneous improvements in lesion burden detected by MRI. All improvements have been sustained for more than three years. This response may be related to the action of zidovudine as a known inhibitor of EBV lytic DNA replication, suggesting future directions for clinical investigation.
Asunto(s)
Infecciones por Virus de Epstein-Barr/complicaciones , Infecciones por Virus de Epstein-Barr/tratamiento farmacológico , Lamivudine/uso terapéutico , Esclerosis Múltiple Recurrente-Remitente/complicaciones , Esclerosis Múltiple Recurrente-Remitente/tratamiento farmacológico , Inhibidores de la Transcriptasa Inversa/uso terapéutico , Zidovudina/uso terapéutico , Adulto , Encéfalo/diagnóstico por imagen , Combinación de Medicamentos , Fatiga/tratamiento farmacológico , Fatiga/etiología , Femenino , Humanos , Factores Inmunológicos/uso terapéutico , Esclerosis Múltiple Recurrente-Remitente/diagnóstico por imagenRESUMEN
The heat shock response (HSR) is a mechanism to cope with proteotoxic stress by inducing the expression of molecular chaperones and other heat shock response genes. The HSR is evolutionarily well conserved and has been widely studied in bacteria, cell lines and lower eukaryotic model organisms. However, mechanistic insights into the HSR in higher eukaryotes, in particular in mammals, are limited. We have developed an in vivo heat shock protocol to analyze the HSR in mice and dissected heat shock factor 1 (HSF1)-dependent and -independent pathways. Whilst the induction of proteostasis-related genes was dependent on HSF1, the regulation of circadian function related genes, indicating that the circadian clock oscillators have been reset, was independent of its presence. Furthermore, we demonstrate that the in vivo HSR is impaired in mouse models of Huntington's disease but we were unable to corroborate the general repression of transcription that follows a heat shock in lower eukaryotes.
Asunto(s)
Factores de Transcripción del Choque Térmico/genética , Respuesta al Choque Térmico/genética , Enfermedad de Huntington/genética , Animales , Relojes Circadianos/genética , Proteínas de Unión al ADN , Modelos Animales de Enfermedad , Humanos , Enfermedad de Huntington/patología , RatonesRESUMEN
Identifying large expansions of short tandem repeats (STRs), such as those that cause amyotrophic lateral sclerosis (ALS) and fragile X syndrome, is challenging for short-read whole-genome sequencing (WGS) data. A solution to this problem is an important step toward integrating WGS into precision medicine. We developed a software tool called ExpansionHunter that, using PCR-free WGS short-read data, can genotype repeats at the locus of interest, even if the expanded repeat is larger than the read length. We applied our algorithm to WGS data from 3001 ALS patients who have been tested for the presence of the C9orf72 repeat expansion with repeat-primed PCR (RP-PCR). Compared against this truth data, ExpansionHunter correctly classified all (212/212, 95% CI [0.98, 1.00]) of the expanded samples as either expansions (208) or potential expansions (4). Additionally, 99.9% (2786/2789, 95% CI [0.997, 1.00]) of the wild-type samples were correctly classified as wild type by this method with the remaining three samples identified as possible expansions. We further applied our algorithm to a set of 152 samples in which every sample had one of eight different pathogenic repeat expansions, including those associated with fragile X syndrome, Friedreich's ataxia, and Huntington's disease, and correctly flagged all but one of the known repeat expansions. Thus, ExpansionHunter can be used to accurately detect known pathogenic repeat expansions and provides researchers with a tool that can be used to identify new pathogenic repeat expansions.
Asunto(s)
Esclerosis Amiotrófica Lateral/genética , Expansión de las Repeticiones de ADN , Secuenciación Completa del Genoma/métodos , Algoritmos , Proteína C9orf72/genética , Bases de Datos Genéticas , Humanos , Medicina de Precisión , Sensibilidad y Especificidad , Programas InformáticosRESUMEN
Expansions of microsatellite repeats are responsible for numerous hereditary diseases in humans, including myotonic dystrophy and Friedreich's ataxia. Whereas the length of an expandable repeat is the main factor determining disease inheritance, recent data point to genomic trans modifiers that can impact the likelihood of expansions and disease progression. Detection of these modifiers may lead to understanding and treating repeat expansion diseases. Here, we describe a method for the rapid, genome-wide identification of trans modifiers for repeat expansion in a yeast experimental system. Using this method, we found that missense mutations in the endoribonuclease subunit (Ysh1) of the mRNA cleavage and polyadenylation complex dramatically increase the rate of (GAA)n repeat expansions but only when they are actively transcribed. These expansions correlate with slower transcription elongation caused by the ysh1 mutation. These results reveal an interplay between RNA processing and repeat-mediated genome instability, confirming the validity of our approach.
Asunto(s)
Ataxia de Friedreich/metabolismo , ARN Mensajero/genética , Replicación del ADN/genética , Replicación del ADN/fisiología , Ataxia de Friedreich/genética , Inestabilidad Genómica/genética , Inestabilidad Genómica/fisiología , Humanos , Mutación/genética , Mutación Puntual/genética , Poliadenilación/genética , Poliadenilación/fisiología , Expansión de Repetición de Trinucleótido/genética , Expansión de Repetición de Trinucleótido/fisiología , Repeticiones de Trinucleótidos/genéticaRESUMEN
Brain microvascular endothelial cells (BMECs) are an essential component of the blood-brain barrier (BBB) that shields the brain against toxins and immune cells. While BBB dysfunction exists in neurological disorders, including Huntington's disease (HD), it is not known if BMECs themselves are functionally compromised to promote BBB dysfunction. Further, the underlying mechanisms of BBB dysfunction remain elusive given limitations with mouse models and post-mortem tissue to identify primary deficits. We undertook a transcriptome and functional analysis of human induced pluripotent stem cell (iPSC)-derived BMECs (iBMEC) from HD patients or unaffected controls. We demonstrate that HD iBMECs have intrinsic abnormalities in angiogenesis and barrier properties, as well as in signaling pathways governing these processes. Thus, our findings provide an iPSC-derived BBB model for a neurodegenerative disease and demonstrate autonomous neurovascular deficits that may underlie HD pathology with implications for therapeutics and drug delivery.
Asunto(s)
Barrera Hematoencefálica/patología , Células Endoteliales/patología , Enfermedad de Huntington/patología , Células Madre Pluripotentes Inducidas/patología , Microvasos/patología , Neovascularización Fisiológica , Vía de Señalización Wnt , Redes Reguladoras de Genes , Humanos , Enfermedad de Huntington/genética , Células Madre Pluripotentes Inducidas/metabolismo , Transcriptoma/genética , Transcitosis , beta Catenina/metabolismoRESUMEN
BACKGROUND: Advances in DNA sequencing technology have resulted in an abundance of personalized data with challenging clinical utility and meaning for clinicians. This wealth of data has potential to dramatically impact the quality of healthcare. Nurses are at the focal point in educating patients regarding relevant healthcare needs; therefore, an understanding of sequencing technology and utilizing these data are critical. AIM: The objective of this study was to explicate the role of nurses and nurse scientists as integral members of healthcare teams in improving understanding of DNA sequencing data and translational genomics for patients. APPROACH: A history of the nurse role in newborn screening is used as an exemplar. DISCUSSION: This study serves as an exemplar on how genome sequencing has been utilized in nursing science and incorporates linkages of other omics approaches used by nurses that are included in this special issue. This special issue showcased nurse scientists conducting multi-omic research from various methods, including targeted candidate genes, pharmacogenomics, proteomics, epigenomics, and the microbiome. From this vantage point, we provide an overview of the roles of nurse scientists in genome sequencing research and provide recommendations for the best utilization of nurses and nurse scientists related to genome sequencing.
Asunto(s)
Enfermería Neonatal/métodos , Tamizaje Neonatal/enfermería , Rol de la Enfermera , Análisis de Secuencia de ADN , Pruebas Genéticas , Genoma Humano , Humanos , Recién Nacido , Investigación Metodológica en EnfermeríaRESUMEN
Mutations that cause neurological phenotypes are highly informative with regard to mechanisms governing human brain function and disease. We report autosomal recessive mutations in the enzyme glutamate pyruvate transaminase 2 (GPT2) in large kindreds initially ascertained for intellectual and developmental disability (IDD). GPT2 [also known as alanine transaminase 2 (ALT2)] is one of two related transaminases that catalyze the reversible addition of an amino group from glutamate to pyruvate, yielding alanine and α-ketoglutarate. In addition to IDD, all affected individuals show postnatal microcephaly and â¼80% of those followed over time show progressive motor symptoms, a spastic paraplegia. Homozygous nonsense p.Arg404* and missense p.Pro272Leu mutations are shown biochemically to be loss of function. The GPT2 gene demonstrates increasing expression in brain in the early postnatal period, and GPT2 protein localizes to mitochondria. Akin to the human phenotype, Gpt2-null mice exhibit reduced brain growth. Through metabolomics and direct isotope tracing experiments, we find a number of metabolic abnormalities associated with loss of Gpt2. These include defects in amino acid metabolism such as low alanine levels and elevated essential amino acids. Also, we find defects in anaplerosis, the metabolic process involved in replenishing TCA cycle intermediates. Finally, mutant brains demonstrate misregulated metabolites in pathways implicated in neuroprotective mechanisms previously associated with neurodegenerative disorders. Overall, our data reveal an important role for the GPT2 enzyme in mitochondrial metabolism with relevance to developmental as well as potentially to neurodegenerative mechanisms.
Asunto(s)
Encéfalo/crecimiento & desarrollo , Mitocondrias/enzimología , Enfermedades del Sistema Nervioso/genética , Transaminasas/genética , Secuencia de Aminoácidos/genética , Animales , Encéfalo/metabolismo , Encéfalo/patología , Ciclo del Ácido Cítrico/genética , Homocigoto , Humanos , Ácidos Cetoglutáricos/metabolismo , Ratones , Mitocondrias/patología , Mutación Missense , Enfermedades del Sistema Nervioso/patología , Fenotipo , Ácido Pirúvico/metabolismo , Transaminasas/metabolismoRESUMEN
The dopamine systems of the brain powerfully influence movement and motivation. We demonstrate that striatonigral fibers originating in striosomes form highly unusual bouquet-like arborizations that target bundles of ventrally extending dopamine-containing dendrites and clusters of their parent nigral cell bodies. Retrograde tracing showed that these clustered cell bodies in turn project to the striatum as part of the classic nigrostriatal pathway. Thus, these striosome-dendron formations, here termed "striosome-dendron bouquets," likely represent subsystems with the nigro-striato-nigral loop that are affected in human disorders including Parkinson's disease. Within the bouquets, expansion microscopy resolved many individual striosomal fibers tightly intertwined with the dopamine-containing dendrites and also with afferents labeled by glutamatergic, GABAergic, and cholinergic markers and markers for astrocytic cells and fibers and connexin 43 puncta. We suggest that the striosome-dendron bouquets form specialized integrative units within the dopamine-containing nigral system. Given evidence that striosomes receive input from cortical regions related to the control of mood and motivation and that they link functionally to reinforcement and decision-making, the striosome-dendron bouquets could be critical to dopamine-related function in health and disease.
Asunto(s)
Dopamina/metabolismo , Neuronas Dopaminérgicas/ultraestructura , Enfermedad de Parkinson/fisiopatología , Sustancia Negra/ultraestructura , Animales , Ganglios Basales/fisiología , Ganglios Basales/ultraestructura , Mapeo Encefálico , Cuerpo Estriado/metabolismo , Cuerpo Estriado/fisiología , Cuerpo Estriado/ultraestructura , Dendrímeros/química , Dendritas/fisiología , Dendritas/ultraestructura , Neuronas Dopaminérgicas/metabolismo , Humanos , Ratones , Neostriado/metabolismo , Neostriado/fisiología , Neostriado/ultraestructura , Enfermedad de Parkinson/metabolismo , Sustancia Negra/metabolismo , Sustancia Negra/fisiologíaRESUMEN
Although dominant gain-of-function triplet repeat expansions in the Huntingtin (HTT) gene are the underlying cause of Huntington disease (HD), understanding the normal functions of nonmutant HTT protein has remained a challenge. We report here findings that suggest that HTT plays a significant role in selective autophagy. Loss of HTT function in Drosophila disrupts starvation-induced autophagy in larvae and conditional knockout of HTT in the mouse CNS causes characteristic cellular hallmarks of disrupted autophagy, including an accumulation of striatal p62/SQSTM1 over time. We observe that specific domains of HTT have structural similarities to yeast Atg proteins that function in selective autophagy, and in particular that the C-terminal domain of HTT shares structural similarity to yeast Atg11, an autophagic scaffold protein. To explore possible functional similarity between HTT and Atg11, we investigated whether the C-terminal domain of HTT interacts with mammalian counterparts of yeast Atg11-interacting proteins. Strikingly, this domain of HTT coimmunoprecipitates with several key Atg11 interactors, including the Atg1/Unc-51-like autophagy activating kinase 1 kinase complex, autophagic receptor proteins, and mammalian Atg8 homologs. Mutation of a phylogenetically conserved WXXL domain in a C-terminal HTT fragment reduces coprecipitation with mammalian Atg8 homolog GABARAPL1, suggesting a direct interaction. Collectively, these data support a possible central role for HTT as an Atg11-like scaffold protein. These findings have relevance to both mechanisms of disease pathogenesis and to therapeutic intervention strategies that reduce levels of both mutant and normal HTT.