RESUMEN

Condensin I and condensin II are multi-subunit complexes that are known for their individual roles in genome organization and preventing genomic instability. However, interactions between condensin I and condensin II subunits and cooperative roles for condensin I and condensin II, outside of their genome organizing functions, have not been reported. We previously discovered that condensin II cooperates with Gamma Interferon Activated Inhibitor of Translation (GAIT) proteins to associate with Long INterspersed Element-1 (LINE-1 or L1) RNA and repress L1 protein expression and the retrotransposition of engineered L1 retrotransposition in cultured human cells. Here, we report that the L1 3'UTR is required for condensin II and GAIT association with L1 RNA, and deletion of the L1 RNA 3'UTR results in increased L1 protein expression and retrotransposition. Interestingly, like condensin II, we report that condensin I also binds GAIT proteins, associates with the L1 RNA 3'UTR, and represses L1 retrotransposition. We provide evidence that the condensin I protein, NCAPD2, is required for condensin II and GAIT protein association with L1 RNA. Furthermore, condensin I and condensin II subunits interact to form a L1-dependent super condensin complex (SCC) which is located primarily within the cytoplasm of both transformed and primary epithelial cells. These data suggest that increases in L1 expression in epithelial cells promote cytoplasmic condensin protein associations that facilitate a feedback loop in which condensins may cooperate to mediate L1 repression.

Asunto(s)

Elementos de Nucleótido Esparcido Largo , Complejos Multiproteicos/metabolismo , Regiones no Traducidas 3' , Adenosina Trifosfatasas/genética , Adenosina Trifosfatasas/metabolismo , Proteínas Cromosómicas no Histona/metabolismo , Proteínas de Unión al ADN , Humanos , Interferón gamma/genética , Proteínas de Unión a Poli-ADP-Ribosa/genética

RESUMEN

New neurotechnologies fueled by the BRAIN Initiative now allow investigators to map, monitor and modulate complex neural circuits, enabling the pursuit of research questions previously considered unapproachable. Yet it is the convergence of molecular neuroscience with the new systems neuroscience that promises the greatest future advances. This is particularly true for our understanding of nervous system disorders, some of which have known molecular drivers or pathology but result in unknown perturbations in circuit function. NIH-supported research on "BRAIN Circuits" programs integrate experimental, analytic, and theoretical capabilities for analysis of specific neural circuits and their contributions to perceptions, motivations, and actions. In this review, we describe the BRAIN priority areas, review our strategy for balancing early feasibility with mature projects, and the balance of individual with team science for this 'BRAIN Circuits' program. We also highlight the diverse portfolio of techniques, species, and neural systems represented in these projects.

Asunto(s)

Encéfalo , Neurociencias , Mapeo Encefálico , Sistema Nervioso Central

RESUMEN

Sirtuin 1 (Sirt1) is a NAD+-dependent deacetylase capable of countering age-related neurodegeneration, but the basis of Sirt1 neuroprotection remains elusive. Spinocerebellar ataxia type 7 (SCA7) is an inherited CAG-polyglutamine repeat disorder. Transcriptome analysis of SCA7 mice revealed downregulation of calcium flux genes accompanied by abnormal calcium-dependent cerebellar membrane excitability. Transcription-factor binding-site analysis of downregulated genes yielded Sirt1 target sites, and we observed reduced Sirt1 activity in the SCA7 mouse cerebellum with NAD+ depletion. SCA7 patients displayed increased poly(ADP-ribose) in cerebellar neurons, supporting poly(ADP-ribose) polymerase-1 upregulation. We crossed Sirt1-overexpressing mice with SCA7 mice and noted rescue of neurodegeneration and calcium flux defects. NAD+ repletion via nicotinamide riboside ameliorated disease phenotypes in SCA7 mice and patient stem cell-derived neurons. Sirt1 thus achieves neuroprotection by promoting calcium regulation, and NAD+ dysregulation underlies Sirt1 dysfunction in SCA7, indicating that cerebellar ataxias exhibit altered calcium homeostasis because of metabolic dysregulation, suggesting shared therapy targets.

Asunto(s)

Calcio/fisiología , Homeostasis/fisiología , Neuroprotección/fisiología , Niacinamida/metabolismo , Sirtuina 1/metabolismo , Ataxias Espinocerebelosas/metabolismo , Animales , Línea Celular , Cerebelo/metabolismo , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Técnicas de Cultivo de Órganos , Transducción de Señal/fisiología , Sirtuina 1/genética , Ataxias Espinocerebelosas/genética , Ataxias Espinocerebelosas/prevención & control

RESUMEN

The maintenance of mitochondrial respiratory function and homeostasis is essential to human health. Here, we identify condensin II subunits as novel regulators of mitochondrial respiration and mitochondrial stress responses. Condensin II is present in the nucleus and cytoplasm. While the effects of condensin II depletion on nuclear genome organization are well studied, the effects on essential cytoplasmic and metabolic processes are not as well understood. Excitingly, we observe that condensin II chromosome-associated protein (CAP) subunits individually localize to different regions of mitochondria, suggesting possible mitochondrial-specific functions independent from those mediated by the canonical condensin II holocomplex. Changes in cellular ATP levels and mitochondrial respiration are observed in condensin II CAP subunit-deficient cells. Surprisingly, we find that loss of NCAPD3 also sensitizes cells to oxidative stress. Together, these studies identify new, and possibly independent, roles for condensin II CAP subunits in preventing mitochondrial damage and dysfunction. These findings reveal a new area of condensin protein research that could contribute to the identification of targets to treat diseases where aberrant function of condensin II proteins is implicated.

Asunto(s)

Adenosina Trifosfatasas/metabolismo , Proteínas de Unión al ADN/metabolismo , Mitocondrias/metabolismo , Complejos Multiproteicos/metabolismo , Estrés Oxidativo/fisiología , Consumo de Oxígeno/fisiología , Adenosina Trifosfatasas/genética , Animales , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Línea Celular , Proteínas de Unión al ADN/genética , Drosophila , Células HT29 , Humanos , Complejos Multiproteicos/genética , Serina Endopeptidasas/genética , Serina Endopeptidasas/metabolismo , Smegmamorpha

RESUMEN

Focused echocardiography may be a useful tool in cardiopulmonary resuscitation for prognostication, to identify certain reversible causes of cardiac arrest, and to guide further management and procedures. Nonetheless, many clinicians have reservations regarding its widespread adoption due to evidence that it leads to prolonged interruption of cardiac compressions. Furthermore, the lack of a clear protocol for the inclusion of focused echocardiography into the rhythm check can lead to confusion in teams not familiar with incorporating the modality, as well as safety concerns for the echosonographer during delivery of a shock. We propose the protocol COACHRED to guide the use of focused echocardiography during rhythm check in a safe and timely manner. This approach incorporates the best strategies identified to date that minimise interruptions to chest compressions. We demonstrate that, in a simulation environment, it is achievable to incorporate focused echocardiography into the rhythm check while keeping the interruption to chest compressions within the timeframe prescribed by international guidelines.

Asunto(s)

Reanimación Cardiopulmonar , Protocolos Clínicos , Ecocardiografía , Paro Cardíaco/diagnóstico por imagen , Paro Cardíaco/terapia , Humanos , Pronóstico

RESUMEN

Spinocerebellar ataxia type 7 (SCA7) is a retinal-cerebellar degenerative disorder caused by CAG-polyglutamine (polyQ) repeat expansions in the ataxin-7 gene. As many SCA7 clinical phenotypes occur in mitochondrial disorders, and magnetic resonance spectroscopy of patients revealed altered energy metabolism, we considered a role for mitochondrial dysfunction. Studies of SCA7 mice uncovered marked impairments in oxygen consumption and respiratory exchange. When we examined cerebellar Purkinje cells in mice, we observed mitochondrial network abnormalities, with enlarged mitochondria upon ultrastructural analysis. We developed stem cell models from patients and created stem cell knockout rescue systems, documenting mitochondrial morphology defects, impaired oxidative metabolism, and reduced expression of nicotinamide adenine dinucleotide (NAD+) production enzymes in SCA7 models. We observed NAD+ reductions in mitochondria of SCA7 patient NPCs using ratiometric fluorescent sensors and documented alterations in tryptophan-kynurenine metabolism in patients. Our results indicate that mitochondrial dysfunction, stemming from decreased NAD+, is a defining feature of SCA7.

Asunto(s)

Enfermedades Mitocondriales/metabolismo , Enfermedades Mitocondriales/patología , Orgánulos/metabolismo , Orgánulos/patología , Ataxias Espinocerebelosas/metabolismo , Ataxias Espinocerebelosas/patología , Tejido Adiposo/metabolismo , Animales , Ataxina-7/genética , Glucemia/metabolismo , Metabolismo Energético , Humanos , Quinurenina/metabolismo , Metabolómica , Ratones , Mitocondrias/metabolismo , Mitocondrias/patología , Enfermedades Mitocondriales/sangre , NAD/metabolismo , Células-Madre Neurales/metabolismo , Péptidos/metabolismo , Fenotipo , Células de Purkinje/metabolismo , Reproducibilidad de los Resultados , Ataxias Espinocerebelosas/sangre , Expansión de Repetición de Trinucleótido/genética , Triptófano/metabolismo

RESUMEN

A perplexing question in neurodegeneration is why different neurons degenerate. The Purkinje cell degeneration (pcd) mouse displays a dramatic phenotype of degeneration of cerebellar Purkinje cells. Loss of CCP1/Nna1 deglutamylation of tubulin accounts for pcd neurodegeneration, but the mechanism is unknown. In this study, we modulated the dosage of fission and fusion genes in a Drosophila melanogaster loss-of-function model and found that mitochondrial fragmentation and disease phenotypes were rescued by reduced Drp1. We observed mitochondrial fragmentation in CCP1 null cells and in neurons from pcd mice, and we documented reduced mitochondrial fusion in cells lacking CCP1. We examined the effect of tubulin hyperglutamylation on microtubule-mediated mitochondrial motility in pcd neurons and noted markedly reduced retrograde axonal transport. Mitochondrial stress promoted Parkin-dependent turnover of CCP1, and CCP1 and Parkin physically interacted. Our results indicate that CCP1 regulates mitochondrial motility through deglutamylation of tubulin and that loss of CCP1-mediated mitochondrial fusion accounts for the exquisite vulnerability of Purkinje neurons in pcd mice.

Asunto(s)

Proteínas del Citoesqueleto/genética , Proteínas de Unión al GTP/genética , Mitocondrias/metabolismo , Proteínas del Tejido Nervioso/genética , Enfermedades Neurodegenerativas/genética , Células de Purkinje/metabolismo , Animales , Transporte Axonal , Proteínas del Citoesqueleto/deficiencia , Modelos Animales de Enfermedad , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Proteínas de Unión al GTP/deficiencia , Regulación de la Expresión Génica , Glutamina/metabolismo , Masculino , Ratones , Ratones Noqueados , Mitocondrias/patología , Dinámicas Mitocondriales , Proteínas del Tejido Nervioso/deficiencia , Enfermedades Neurodegenerativas/metabolismo , Enfermedades Neurodegenerativas/patología , Fenotipo , Células de Purkinje/patología , Células de Purkinje/ultraestructura , Transducción de Señal , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo

RESUMEN

The Condensin II complex plays important, conserved roles in genome organization throughout the cell cycle and in the regulation of gene expression. Previous studies have linked decreased Condensin II subunit expression with a variety of diseases. Here, we show that elevated levels of Condensin II subunits are detected in somatic cancers. To evaluate potential biological effects of elevated Condensin II levels, we overexpressed the Condensin II subunit, dCAP-D3 in Drosophila melanogaster larval tissues and examined the effects on the mitotic- and interphase-specific functions of Condensin II. Interestingly, while ubiquitous overexpression resulted in pupal lethality, tissue specific overexpression of dCAP-D3 caused formation of nucleoplasmic protein aggregates which slowed mitotic prophase progression, mimicking results observed when dCAP-D3 levels are depleted. Surprisingly, dCAP-D3 aggregate formation resulted in faster transitions from metaphase to anaphase. Overexpressed dCAP-D3 protein failed to precipitate other Condensin II subunits in nondividing tissues, but did cause changes to gene expression which occurred in a manner opposite of what was observed when dCAP-D3 levels were depleted in both dividing and nondividing tissues. Our findings show that altering dCAP-D3 levels in either direction has detrimental effects on mitotic timing, the regulation of gene expression, and organism development. Taken together, these data suggest that the different roles for Condensin II throughout the cell cycle may be independent of each other and/or that dCAP-D3 may possess functions that are separate from those involving its association with the Condensin II complex. If conserved, these findings could have implications for tumors harboring elevated CAP-D3 levels.

Asunto(s)

Adenosina Trifosfatasas/genética , Proteínas de Unión al ADN/genética , Proteínas de Drosophila/genética , Complejos Multiproteicos/genética , Adenosina Trifosfatasas/metabolismo , Animales , Proteínas de Unión al ADN/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Desarrollo Embrionario/genética , Regulación del Desarrollo de la Expresión Génica , Mitosis , Complejos Multiproteicos/metabolismo

RESUMEN

LINE-1 (L1) retrotransposons can mobilize (retrotranspose) within the human genome, and mutagenic de novo L1 insertions can lead to human diseases, including cancers. As a result, cells are actively engaged in preventing L1 retrotransposition. This work reveals that the human Condensin II complex restricts L1 retrotransposition in both non-transformed and transformed cell lines through inhibition of L1 transcription and translation. Condensin II subunits, CAP-D3 and CAP-H2, interact with members of the Gamma-Interferon Activated Inhibitor of Translation (GAIT) complex including the glutamyl-prolyl-tRNA synthetase (EPRS), the ribosomal protein L13a, Glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and NS1 associated protein 1 (NSAP1). GAIT has been shown to inhibit translation of mRNAs encoding inflammatory proteins in myeloid cells by preventing the binding of the translation initiation complex, in response to Interferon gamma (IFN-γ). Excitingly, our data show that Condensin II promotes complexation of GAIT subunits. Furthermore, RNA-Immunoprecipitation experiments in epithelial cells demonstrate that Condensin II and GAIT subunits associate with L1 RNA in a co-dependent manner, independent of IFN-γ. These findings suggest that cooperation between the Condensin II and GAIT complexes may facilitate a novel mechanism of L1 repression, thus contributing to the maintenance of genome stability in somatic cells.

Asunto(s)

Proteínas de Ciclo Celular/genética , Interferón gamma/genética , Elementos de Nucleótido Esparcido Largo/genética , Proteínas Nucleares/genética , Adenosina Trifosfatasas/genética , Proteínas de Unión al ADN/genética , Células Epiteliales/metabolismo , Genoma Humano , Humanos , Factor 3 de Genes Estimulados por el Interferón/genética , Complejos Multiproteicos/genética , Unión Proteica , Inhibidores de la Síntesis de la Proteína , ARN Mensajero/genética , Retroelementos/genética

Asunto(s)

Competencia Clínica , Liderazgo , Enfermeras Administradoras , Personal de Enfermería en Hospital/organización & administración , Atención a la Salud/organización & administración , Predicción , Hospitales Pediátricos , Humanos , Modelos de Enfermería , Rol de la Enfermera , Investigación en Administración de Enfermería , Investigación en Evaluación de Enfermería , Texas

Asunto(s)

Daño del ADN/genética , Enzimas Reparadoras del ADN/genética , Enfermedad de Machado-Joseph/genética , Proteínas del Tejido Nervioso/genética , Proteínas Nucleares/genética , Fosfotransferasas (Aceptor de Grupo Alcohol)/genética , Proteínas Represoras/genética , Humanos

RESUMEN

Genome-wide studies have revealed that genes commonly have a high density of RNA polymerase II just downstream of the transcription start site. This has raised the possibility that genes are commonly regulated by transcriptional elongation, but this remains largely untested in vivo, particularly in vertebrates. Here, we show that the proximal promoter from the Rhox5 homeobox gene recruits polymerase II and begins elongating in all tissues and cell lines that we tested, but it only completes elongation in a tissue-specific and developmentally regulated manner. Relief of the elongation block is associated with recruitment of the elongation factor P-TEFb, the co-activator GRIP1, the chromatin remodeling factor BRG1, and specific histone modifications. We provide evidence that two mechanisms relieve the elongation block at the proximal promoter: demethylation and recruitment of androgen receptor. Together, our findings support a model in which promoter proximal pausing helps confer tissue-specific and developmental gene expression through a mechanism regulated by DNA demethylation-dependent nuclear hormone receptor recruitment.

Asunto(s)

Metilación de ADN , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Especificidad de Órganos , Testosterona/farmacología , Elongación de la Transcripción Genética/efectos de los fármacos , Andrógenos/farmacología , Animales , Línea Celular , Células HeLa , Histonas/metabolismo , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Humanos , Hígado/crecimiento & desarrollo , Hígado/metabolismo , Masculino , Ratones , Factor B de Elongación Transcripcional Positiva/metabolismo , Regiones Promotoras Genéticas/genética , ARN Polimerasa II/metabolismo , Receptores Androgénicos/genética , Receptores Androgénicos/metabolismo , Elementos de Respuesta/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Vesículas Seminales/crecimiento & desarrollo , Vesículas Seminales/metabolismo , Testículo/crecimiento & desarrollo , Testículo/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo

Asunto(s)

Trastornos del Conocimiento/genética , Discapacidad Intelectual/genética , Proteínas de la Membrana/genética , Mutación/fisiología , Degeneraciones Espinocerebelosas/genética , Femenino , Humanos , Masculino

RESUMEN

Deconstructing the mechanistic basis of neurodegenerative disorders, such as Huntington's disease (HD), has been a particularly challenging undertaking, relying mostly on post-mortem tissue samples, non-neural cell lines from affected individuals, and model organisms. Two articles recently published in Cell Stem Cell report first the generation and characterization of induced pluripotent stem cell (iPSC)-derived models for HD, and second, the genetic correction of a disease-causing CAG expansion mutation in iPSCs from individuals with HD. Taken together, these two studies provide a framework for the production and validation of iPSC materials for human neurodegenerative disease research and yield crucial tools for investigating future therapies.

RESUMEN

BACKGROUND: This study trialled the outcome for asthma patients of a brief, nurse led, patient education session with general practice review of an Asthma Action Plan. METHODS: Prospective cohort with before-after measures conducted in six rural general practices. Outcome measures were changes over 12 months in self reported asthma control, quality of life, device use, and unscheduled general practice and emergency department visits for asthma exacerbation. RESULTS: Eighty-three patients participated. Mean asthma control score decreased but did not reach statistical significance (p=0.124). Quality of life improved for adults (Wilcoxon rank signed test for two related samples p<0.001). The proportion of patients who had one or more unscheduled visits to their general practitioner over 12 months decreased from 23% to 13% (p=0.178) and emergency department presentations decreased from 9% to 4% (p=0.102). DISCUSSION: Structured general practice based education appears to be an effective preventive health care program, with the potential to reduce expensive unscheduled use of health services.

Asunto(s)

Asma/tratamiento farmacológico , Educación del Paciente como Asunto/métodos , Población Rural , Autocuidado , Resultado del Tratamiento , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Asma/enfermería , Niño , Intervalos de Confianza , Femenino , Médicos Generales , Indicadores de Salud , Humanos , Masculino , Inhaladores de Dosis Medida , Persona de Mediana Edad , Relaciones Enfermero-Paciente , Proyectos Piloto , Estudios Prospectivos , Calidad de Vida , Estadística como Asunto , Encuestas y Cuestionarios , Adulto Joven

RESUMEN

Chironomids may adapt to pollution stress but data are confined to species that can be reared in the laboratory. A microcosm approach was used to test for adaptation and species differences in heavy metal tolerance. In one experiment, microcosms containing different levels of contaminants were placed in polluted and reference locations. The response of Chironomus februarius to metal contaminants suggested local adaptation: relatively more flies emerged from clean sediment at the reference site and the reverse pattern occurred at the polluted site. However, maternal effects were not specifically ruled out. In another species, Kiefferulus intertinctus, there was no evidence for adaptation. In a second experiment, microcosms with different contaminant levels were placed at two polluted and two unpolluted sites. Species responded differently to contaminants, but there was no evidence for adaptation in the species where this could be tested. Adaptation to heavy metals may be uncommon and species specific, but more sensitive species need to be tested across a range of pollution levels. Factors influencing the likelihood of adaptation are briefly discussed.

Asunto(s)

Aclimatación , Chironomidae/efectos de los fármacos , Sedimentos Geológicos/química , Metales Pesados/toxicidad , Contaminantes Químicos del Agua/toxicidad , Animales , Biodiversidad , Chironomidae/clasificación , Chironomidae/fisiología , Agua Dulce/análisis , Metales Pesados/análisis , Especificidad de la Especie , Contaminantes Químicos del Agua/análisis