RESUMEN
Patients with asthma experience elevated rates of mental illness. However, the molecular links underlying such lung-brain crosstalk remain ambiguous. Hypothalamic dysfunction is observed in many psychiatric disorders, particularly those with an inflammatory component due to many hypothalamic regions being unprotected by the blood-brain barrier. To gain a better insight into such neuropsychiatric sequelae, this study investigated gene expression differences in the hypothalamus following lung inflammation (asthma) induction in mice, using RNA transcriptome profiling. BALB/c mice were challenged with either bacterial lipopolysaccharide (LPS, E. coli) or ovalbumin (OVA) allergens or saline control (n = 7 per group), and lung inflammation was confirmed via histological examination of postmortem lung tissue. The majority of the hypothalamus was micro-dissected, and total RNA was extracted for sequencing. Differential expression analysis identified 31 statistically significant single genes (false discovery rate FDR5%) altered in expression following LPS exposure compared to controls; however, none were significantly changed following OVA treatment, suggesting a milder hypothalamic response. When gene sets were examined, 48 were upregulated and 8 were downregulated in both asthma groups relative to controls. REACTOME enrichment analysis suggests these gene sets are involved in signal transduction metabolism, immune response and neuroplasticity. Interestingly, we identified five altered gene sets directly associated with neurotransmitter signaling. Intriguingly, many of these altered gene sets can influence mental health and or/neuroinflammation in humans. These findings help characterize the links between asthma-induced lung inflammation and the brain and may assist in identifying relevant pathways and therapeutic targets for future intervention.
Asunto(s)
Asma , Modelos Animales de Enfermedad , Hipotálamo , Lipopolisacáridos , Pulmón , Ratones Endogámicos BALB C , Transcriptoma , Animales , Asma/genética , Asma/metabolismo , Asma/patología , Hipotálamo/metabolismo , Ratones , Pulmón/metabolismo , Pulmón/patología , Ovalbúmina , Perfilación de la Expresión Génica , Femenino , Regulación de la Expresión GénicaRESUMEN
Oculopharyngodistal myopathy (OPDM) is an inherited myopathy manifesting with ptosis, dysphagia and distal weakness. Pathologically it is characterised by rimmed vacuoles and intranuclear inclusions on muscle biopsy. In recent years CGG ⢠CCG repeat expansion in four different genes were identified in OPDM individuals in Asian populations. None of these have been found in affected individuals of non-Asian ancestry. In this study we describe the identification of CCG expansions in ABCD3, ranging from 118 to 694 repeats, in 35 affected individuals across eight unrelated OPDM families of European ancestry. ABCD3 transcript appears upregulated in fibroblasts and skeletal muscle from OPDM individuals, suggesting a potential role of over-expression of CCG repeat containing ABCD3 transcript in progressive skeletal muscle degeneration. The study provides further evidence of the role of non-coding repeat expansions in unsolved neuromuscular diseases and strengthens the association between the CGG ⢠CCG repeat motif and a specific pattern of muscle weakness.
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Músculo Esquelético , Expansión de Repetición de Trinucleótido , Población Blanca , Humanos , Masculino , Femenino , Adulto , Expansión de Repetición de Trinucleótido/genética , Persona de Mediana Edad , Población Blanca/genética , Músculo Esquelético/patología , Transportadoras de Casetes de Unión a ATP/genética , Miopatías Estructurales Congénitas/genética , Miopatías Estructurales Congénitas/patología , Linaje , Anciano , Adulto Joven , Fibroblastos/metabolismo , Fibroblastos/patología , Debilidad Muscular/genética , Debilidad Muscular/patología , Adolescente , Distrofias MuscularesRESUMEN
Relaxin-family peptide 3 receptor (RXFP3) is activated by relaxin-3 in the brain to influence arousal and related functions, such as feeding and stress responses. Two transgenic mouse lines have recently been developed that co-express different fluorophores within RXFP3-expressing neurons: either yellow fluorescent protein (YFP; RXFP3-Cre/YFP mice) or tdTomato (RXFP3-Cre/tdTomato mice). To date, the characteristics of neurons that express RXFP3-associated fluorophores in these mice have only been investigated in the bed nucleus of the stria terminalis and the hypothalamic arcuate nucleus. To better determine the utility of these fluorophore-expressing mice for further research, we characterised the neuroanatomical distribution of fluorophores throughout the brain of these mice and compared this to the published distribution of Rxfp3 mRNA (detected by in situ hybridisation) in wildtype mice. Coronal sections of RXFP3-Cre/YFP (n = 8) and RXFP3-Cre/tdTomato (n = 8) mouse brains were imaged, and the density of fluorophore-expressing cells within various brain regions/nuclei was qualitatively assessed. Comparisons with our previously reported RXFP3 mRNA distribution revealed that of 212 brain regions that contained either fluorophore or RXFP3 mRNA, approximately half recorded densities that were within two qualitative measurements of each other (on a 9-point scale), including hippocampal dentate gyrus and amygdala subregions. However, many brain areas with likely non-authentic, false-positive, or false-negative fluorophore expression were also detected, including the cerebellum. Therefore, this study provides a guide to which brain regions should be prioritized for future study of RXFP3 in these mice, to better understand the neuroanatomy and function of this intriguing, neuronal peptide receptor.
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Encéfalo , Proteínas Luminiscentes , Ratones Transgénicos , Receptores Acoplados a Proteínas G , Animales , Ratones , Proteínas Luminiscentes/genética , Proteínas Luminiscentes/metabolismo , Encéfalo/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Receptores Acoplados a Proteínas G/genética , Masculino , Colorantes Fluorescentes , Neuronas/metabolismo , Integrasas/genética , Integrasas/metabolismo , Ratones Endogámicos C57BL , Proteína Fluorescente Roja , Proteínas BacterianasRESUMEN
Tandem repeat DNA sequences constitute a significant proportion of the human genome. While previously considered to be functionally inert, these sequences are now broadly accepted as important contributors to genetic diversity. However, the polymorphic nature of these sequences can lead to expansion beyond a gene-specific threshold, causing disease. More than 50 pathogenic repeat expansions have been identified to date, many of which have been discovered in the last decade as a result of advances in sequencing technologies and associated bioinformatic tools. Commonly utilised diagnostic platforms including Sanger sequencing, capillary array electrophoresis, and Southern blot are generally low throughput and are often unable to accurately determine repeat size, composition, and epigenetic signature, which are important when characterising repeat expansions. The rapid advances in bioinformatic tools designed specifically to interrogate short-read sequencing and the development of long-read single molecule sequencing is enabling a new generation of high throughput testing for repeat expansion disorders. In this review, we discuss some of the challenges surrounding the identification and characterisation of disease-causing repeat expansions and the technological advances that are poised to translate the promise of genomic medicine to individuals and families affected by these disorders.
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Biología Computacional , Secuencias Repetidas en Tándem , Humanos , Análisis de Secuencia de ADN/métodos , Secuenciación de Nucleótidos de Alto Rendimiento/métodosRESUMEN
Adult-onset cerebellar ataxias are a group of neurodegenerative conditions that challenge both genetic discovery and molecular diagnosis. In this study, we identified an intronic (GAA) repeat expansion in fibroblast growth factor 14 (FGF14). Genetic analysis of 95 Australian individuals with adult-onset ataxia identified four (4.2%) with (GAA)>300 and a further nine individuals with (GAA)>250. PCR and long-read sequence analysis revealed these were pure (GAA) repeats. In comparison, no control subjects had (GAA)>300 and only 2/311 control individuals (0.6%) had a pure (GAA)>250. In a German validation cohort, 9/104 (8.7%) of affected individuals had (GAA)>335 and a further six had (GAA)>250, whereas 10/190 (5.3%) control subjects had (GAA)>250 but none were (GAA)>335. The combined data suggest (GAA)>335 are disease causing and fully penetrant (p = 6.0 × 10-8, OR = 72 [95% CI = 4.3-1,227]), while (GAA)>250 is likely pathogenic with reduced penetrance. Affected individuals had an adult-onset, slowly progressive cerebellar ataxia with variable features including vestibular impairment, hyper-reflexia, and autonomic dysfunction. A negative correlation between age at onset and repeat length was observed (R2 = 0.44, p = 0.00045, slope = -0.12) and identification of a shared haplotype in a minority of individuals suggests that the expansion can be inherited or generated de novo during meiotic division. This study demonstrates the power of genome sequencing and advanced bioinformatic tools to identify novel repeat expansions via model-free, genome-wide analysis and identifies SCA50/ATX-FGF14 as a frequent cause of adult-onset ataxia.
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Ataxia Cerebelosa , Factores de Crecimiento de Fibroblastos , Ataxia de Friedreich , Expansión de Repetición de Trinucleótido , Adulto , Humanos , Ataxia/genética , Australia , Ataxia Cerebelosa/genética , Ataxia de Friedreich/genética , Expansión de Repetición de Trinucleótido/genéticaRESUMEN
Microglia play an important role in the pathogenesis of multiple sclerosis and the mouse model of MS, experimental autoimmune encephalomyelitis (EAE). To more fully understand the role of microglia in EAE we characterized microglial transcriptomes before the onset of motor symptoms (pre-onset) and during symptomatic EAE. We compared the transcriptome in brain, where behavioral changes are initiated, and spinal cord, where damage is revealed as motor and sensory deficits. We used a RiboTag strategy to characterize ribosome-bound mRNA only in microglia without incurring possible transcriptional changes after cell isolation. Brain and spinal cord samples clustered separately at both stages of EAE, indicating regional heterogeneity. Differences in gene expression were observed in the brain and spinal cord of pre-onset and symptomatic animals with most profound effects in the spinal cord of symptomatic animals. Canonical pathway analysis revealed changes in neuroinflammatory pathways, immune functions and enhanced cell division in both pre-onset and symptomatic brain and spinal cord. We also observed a continuum of many pathways at pre-onset stage that continue into the symptomatic stage of EAE. Our results provide additional evidence of regional and temporal heterogeneity in microglial gene expression patterns that may help in understanding mechanisms underlying various symptomology in MS.
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Encefalomielitis Autoinmune Experimental/metabolismo , Esclerosis Múltiple/metabolismo , Animales , Secuencia de Bases , Femenino , Técnica del Anticuerpo Fluorescente , Ratones , Microglía , ARN Mensajero/metabolismo , Transmisión Sináptica/fisiología , Transcriptoma/genéticaRESUMEN
Early-life inflammatory stress increases seizure susceptibility later in life. However, possible sex- and age-specific differences and the associated mechanisms are largely unknown. C57BL/6 mice were bred in house, and female and male pups were injected with lipopolysaccharide (LPS; 100 µg/kg, i.p.) or vehicle control (saline solution) at postnatal day 14 (P14). Seizure threshold was assessed in response to pentylenetetrazol (1% solution, i.v.) in adolescence (â¼P40) and adulthood (â¼P60). We found that adult, but not adolescent, mice treated with LPS displayed â¼34% lower seizure threshold compared with controls. Females and males showed similar increased seizure susceptibility, suggesting that altered brain excitability was age dependent, but not sex dependent. Whole-cell recordings revealed no differences in excitatory synaptic activity onto CA1 pyramidal neurons from control or neonatally inflamed adolescent mice of either sex. However, adult mice of both sexes previously exposed to LPS displayed spontaneous EPSC frequency approximately twice that of controls, but amplitude was unchanged. Although these changes were not associated with alterations in dendritic spines or in the NMDA/AMPA receptor ratio, they were linked to an increased glutamate release probability from Schaffer collateral, but not temporoammonic pathway. This glutamate increase was associated with reduced activity of presynaptic GABAB receptors and was independent of the endocannabinoid-mediated suppression of excitation. Our new findings demonstrate that early-life inflammation leads to long-term increased hippocampal excitability in adult female and male mice associated with changes in glutamatergic synaptic transmission. These alterations may contribute to enhanced vulnerability of the brain to subsequent pathologic challenges such as epileptic seizures.SIGNIFICANCE STATEMENT Adult physiology has been shown to be affected by early-life inflammation. Our data reveal that early-life inflammation increases excitatory synaptic transmission onto hippocampal CA1 pyramidal neurons in an age-dependent manner through disrupted presynaptic GABAB receptor activity on Schaffer collaterals. This hyperexcitability was seen only in adult, and not in adolescent, animals of either sex. The data suggest a maturation process, independent of sex, in the priming action of early-life inflammation and highlight the importance of studying mature brains to reveal cellular changes associated with early-life interventions.
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Inflamación/fisiopatología , Células Piramidales/fisiología , Convulsiones/fisiopatología , Transmisión Sináptica/fisiología , Animales , Convulsivantes/toxicidad , Potenciales Postsinápticos Excitadores/fisiología , Femenino , Hipocampo/efectos de los fármacos , Hipocampo/fisiopatología , Inflamación/inducido químicamente , Lipopolisacáridos/toxicidad , Masculino , Ratones , Ratones Endogámicos C57BL , Pentilenotetrazol/toxicidad , Convulsiones/inducido químicamenteRESUMEN
RXFP3 (relaxin-family peptide 3 receptor) is the cognate G-protein-coupled receptor for the neuropeptide, relaxin-3. RXFP3 is expressed widely throughout the brain, including the hypothalamus, where it has been shown to modulate feeding behavior and neuroendocrine activity in rodents. In order to better characterize its potential mechanisms of action, this study determined whether RXFP3 is expressed by dopaminergic neurons within the arcuate nucleus (ARC) and dorsomedial hypothalamus (DMH), in addition to the ventral tegmental area (VTA). Neurons that express RXFP3 were visualized in coronal brain sections from RXFP3-Cre/tdTomato mice, which express the tdTomato fluorophore within RXFP3-positive cells, and dopaminergic neurons in these areas were visualized by simultaneous immunohistochemical detection of tyrosine hydroxylase-immunoreactivity (TH-IR). Approximately 20% of ARC neurons containing TH-IR coexpressed tdTomato fluorescence, suggesting that RXFP3 can influence the dopamine pathway from the ARC to the pituitary gland that controls prolactin release. The ability of prolactin to reduce leptin sensitivity and increase food consumption therefore represents a potential mechanism by which RXFP3 activation influences feeding. A similar proportion of DMH neurons containing TH-IR expressed RXFP3-related tdTomato fluorescence, consistent with a possible RXFP3-mediated regulation of stress and neuroendocrine circuits. In contrast, RXFP3 was barely detected within the VTA. TdTomato signal was absent from the ARC and DMH in sections from Rosa26-tdTomato mice, suggesting that the cells identified in RXFP3-Cre/tdTomato mice expressed authentic RXFP3-related tdTomato fluorescence. Together, these findings identify potential hypothalamic mechanisms through which RXFP3 influences neuroendocrine control of metabolism, and further highlight the therapeutic potential of targeting RXFP3 in feeding-related disorders.
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BACKGROUND/AIMS: Amyloid plaques, generated during the progression of Alzheimer's disease, cause major neurological deficits due to substantial cell toxicity and death. The underlying cause of plaque generation stems from cleavage of the amyloid precursor protein (APP) by ß-secretase (BACE1). A resulting amyloid-ß (Aß) fragment forms aggregates to produce the main constituent of a plaque. METHODS: Phage display and biopanning techniques were used to identify a 12-mer peptide that had a natural affinity for the BACE1 enzyme. The peptide was translated from phage DNA and synthetically produced. The peptide, at concentrations of 1nM, 10nM and 100nM, was used to confirm binding by direct assay. Non-specific binding to BACE2, renin and cathepsin D was tested by direct binding assay. A BACE1 activity assay was used to determine the peptide effect on cleavage of an APP substrate. Treatment of SY5Y cells with the peptide was used to determine toxicity and prevention of Aß40 and Aß42 production. RESULTS: After identification and synthetic production, the peptide exhibited a strong affinity for BACE1 at nanomolar concentrations in the direct assay. In case of non-specific binding to homologous BACE2, renin and cathepsin D, the peptide showed minor binding but was nullified when in solution with BACE1. The peptide addition to a BACE1 activity assay was able to significantly reduce the amount of substrate cleavage. SY5Y cells, when treated with the peptide, did not show any detrimental morphological changes while being able to reduce the production of natural Aß40 and Aß42. Even under stressed conditions (H2O2 treatment) where the Aß production was higher, the peptide was still able to significantly reduce the effect of BACE1 while not effecting cell viability. CONCLUSION: The identified peptide exhibited strong binding to BACE1 in vitro and was able to reduce production of Aß, suggesting a favourable BACE1 inhibitor for future refining and characterisation.
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Enfermedad de Alzheimer/tratamiento farmacológico , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Péptidos beta-Amiloides/antagonistas & inhibidores , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Fragmentos de Péptidos/antagonistas & inhibidores , Péptidos/farmacología , Enfermedad de Alzheimer/metabolismo , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Péptidos beta-Amiloides/metabolismo , Ácido Aspártico Endopeptidasas/metabolismo , Línea Celular , Descubrimiento de Drogas , Inhibidores Enzimáticos/metabolismo , Humanos , Fragmentos de Péptidos/metabolismo , Péptidos/metabolismoRESUMEN
Early life, systemic inflammation causes long-lasting changes in behavior. To unmask possible mechanisms associated with this phenomenon, we asked whether the intrinsic membrane properties in hippocampal neurons were altered as a consequence of early life inflammation. C57BL/6 mice were bred in-house and both male and female pups from multiple litters were injected with lipopolysaccharide (LPS; 100 µg/kg, i.p.) or vehicle at postnatal day (P)14, and kept until adolescence (P35-P45) or adulthood (P60-P70), when brain slices were prepared for whole-cell and perforated-patch recordings from CA1 hippocampal pyramidal neurons. In neurons of adult male mice pretreated with LPS, the number of action potentials elicited by depolarizing current pulses was significantly increased compared with control neurons, concomitant with increased input resistance, and a lower action potential threshold. Although these changes were not associated with changes in relevant sodium channel expression or differences in capacitance or dendritic architecture, they were linked to a mechanism involving intracellular chloride overload, revealed through a depolarized GABA reversal potential and increased expression of the chloride transporter, NKCC1. In contrast, no significant changes were observed in neurons of adult female mice pretreated with LPS, nor in adolescent mice of either sex. These data uncover a potential mechanism involving neonatal inflammation-induced plasticity in chloride homeostasis, which may contribute to early life inflammation-induced behavioral alterations.SIGNIFICANCE STATEMENT Early life inflammation results in long-lasting changes in many aspects of adult physiology. In this paper we reveal that a brief exposure to early life peripheral inflammation with LPS increases excitability in hippocampal neurons in a sex- and age-dependent manner through a chloride homeostasis disruption. As this hyperexcitability was only seen in adult males, and not in adult females or adolescent animals of either sex, it raises the possibility of a hormonal interaction with early life inflammation. Furthermore, as neonatal inflammation is a normal feature of early life in most animals, as well as humans, these findings may be very important for the development of animal models of disease that more appropriately resemble the human condition.
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Región CA1 Hipocampal/metabolismo , Homeostasis/fisiología , Inflamación/metabolismo , Células Piramidales/metabolismo , Caracteres Sexuales , Miembro 2 de la Familia de Transportadores de Soluto 12/metabolismo , Factores de Edad , Animales , Región CA1 Hipocampal/efectos de los fármacos , Femenino , Homeostasis/efectos de los fármacos , Inflamación/inducido químicamente , Lipopolisacáridos/toxicidad , Masculino , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Ratones , Ratones Endogámicos C57BL , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Células Piramidales/efectos de los fármacos , Factores SexualesRESUMEN
Dark matter-only simulations of galaxy formation predict many more subhalos around a Milky Way-like galaxy than the number of observed satellites. Proposed solutions require the satellites to inhabit dark matter halos with masses 10(9)-10(10 )Msun at the time they fell into the Milky Way. Here we use a modelling approach, independent of cosmological simulations, to obtain a pre-infall mass of 3.6(-2.3)(+3.8) × 10(8) Msun for one of the Milky Way's satellites: Carina. This determination of a low halo mass for Carina can be accommodated within the standard model only if galaxy formation becomes stochastic in halos below â¼10(10 )Msun. Otherwise Carina, the eighth most luminous Milky Way dwarf, would be expected to inhabit a significantly more massive halo. The implication of this is that a population of 'dark dwarfs' should orbit the Milky Way: halos devoid of stars and yet more massive than many of their visible counterparts.
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Histone acetyltransferases (HATs) and histone deacetylases (HDACs) promote histone posttranslational modifications, which lead to an epigenetic alteration in gene expression. Aberrant regulation of HATs and HDACs in neuronal cells results in pathological consequences such as neurodegeneration. Alzheimer's disease is the most common neurodegenerative disease of the brain, which has devastating effects on patients and loved ones. The use of pan-HDAC inhibitors has shown great therapeutic promise in ameliorating neurodegenerative ailments. Recent evidence has emerged suggesting that certain deacetylases mediate neurotoxicity, whereas others provide neuroprotection. Therefore, the inhibition of certain isoforms to alleviate neurodegenerative manifestations has now become the focus of studies. In this review, we aimed to discuss and summarize some of the most recent and promising findings of HAT and HDAC functions in neurodegenerative diseases.
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Epigénesis Genética , Enfermedades Neurodegenerativas/genética , Neuronas/metabolismo , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/metabolismo , Cognición , Epigénesis Genética/efectos de los fármacos , Epigenómica , Regulación de la Expresión Génica/efectos de los fármacos , Histona Acetiltransferasas/metabolismo , Inhibidores de Histona Desacetilasas/farmacología , Inhibidores de Histona Desacetilasas/uso terapéutico , Histona Desacetilasas/metabolismo , Histonas/metabolismo , Humanos , Enfermedades Neurodegenerativas/tratamiento farmacológico , Enfermedades Neurodegenerativas/metabolismoRESUMEN
Euclid is a European Space Agency medium-class mission selected for launch in 2019 within the Cosmic Vision 2015-2025 program. The main goal of Euclid is to understand the origin of the accelerated expansion of the universe. Euclid will explore the expansion history of the universe and the evolution of cosmic structures by measuring shapes and red-shifts of galaxies as well as the distribution of clusters of galaxies over a large fraction of the sky. Although the main driver for Euclid is the nature of dark energy, Euclid science covers a vast range of topics, from cosmology to galaxy evolution to planetary research. In this review we focus on cosmology and fundamental physics, with a strong emphasis on science beyond the current standard models. We discuss five broad topics: dark energy and modified gravity, dark matter, initial conditions, basic assumptions and questions of methodology in the data analysis. This review has been planned and carried out within Euclid's Theory Working Group and is meant to provide a guide to the scientific themes that will underlie the activity of the group during the preparation of the Euclid mission.