Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Pineal Res ; 68(2): e12624, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31742766

RESUMO

Melatonin is a pleiotrophic hormone, synthesised primarily by the pineal gland under the control of the suprachiasmatic nuclei (SCN). It not only provides a hormonal signal of darkness but also has neuroprotective properties. Huntington's disease (HD) is a progressive neurodegenerative disorder characterised by abnormal motor, cognitive and psychiatric symptoms. There is growing evidence, particularly from animal models, that circadian rhythms may also be disturbed in HD. We measured two circadian-regulated hormones, melatonin and cortisol, in plasma samples collected around-the-clock from normal and presymptomatic transgenic HD sheep (Ovis aries) at 5 and 7 years of age, to assess SCN-driven rhythms and the effect of genotype, sex and age. Melatonin-related precursors and metabolites (tryptophan, serotonin, kynurenine) were also measured by liquid chromatography (LC)-mass spectrometry (MS). At 5 years of age in both rams and ewes, plasma melatonin levels were significantly elevated in HD sheep. In ewes measured 2 years later, there was still a significant elevation of nocturnal melatonin. Furthermore, the daytime baseline levels of melatonin were significantly higher in HD sheep. Since increased melatonin could have global beneficial effects on brain function, we suggest that the increased melatonin measured in presymptomatic HD sheep is part of an autoprotective response to mutant huntingtin toxicity that may account, at least in part, for the late onset of disease that characterises HD.

2.
Proc Natl Acad Sci U S A ; 114(52): E11293-E11302, 2017 12 26.
Artigo em Inglês | MEDLINE | ID: mdl-29229845

RESUMO

The neurodegenerative disorder Huntington's disease (HD) is typically characterized by extensive loss of striatal neurons and the midlife onset of debilitating and progressive chorea, dementia, and psychological disturbance. HD is caused by a CAG repeat expansion in the Huntingtin (HTT) gene, translating to an elongated glutamine tract in the huntingtin protein. The pathogenic mechanism resulting in cell dysfunction and death beyond the causative mutation is not well defined. To further delineate the early molecular events in HD, we performed RNA-sequencing (RNA-seq) on striatal tissue from a cohort of 5-y-old OVT73-line sheep expressing a human CAG-expansion HTT cDNA transgene. Our HD OVT73 sheep are a prodromal model and exhibit minimal pathology and no detectable neuronal loss. We identified significantly increased levels of the urea transporter SLC14A1 in the OVT73 striatum, along with other important osmotic regulators. Further investigation revealed elevated levels of the metabolite urea in the OVT73 striatum and cerebellum, consistent with our recently published observation of increased urea in postmortem human brain from HD cases. Extending that finding, we demonstrate that postmortem human brain urea levels are elevated in a larger cohort of HD cases, including those with low-level neuropathology (Vonsattel grade 0/1). This elevation indicates increased protein catabolism, possibly as an alternate energy source given the generalized metabolic defect in HD. Increased urea and ammonia levels due to dysregulation of the urea cycle are known to cause neurologic impairment. Taken together, our findings indicate that aberrant urea metabolism could be the primary biochemical disruption initiating neuropathogenesis in HD.


Assuntos
Corpo Estriado/metabolismo , Doença de Huntington/metabolismo , Ureia/metabolismo , Adulto , Animais , Animais Geneticamente Modificados , Corpo Estriado/patologia , Modelos Animais de Doenças , Feminino , Humanos , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Doença de Huntington/genética , Doença de Huntington/patologia , Masculino , Ovinos , Expansão das Repetições de Trinucleotídeos/genética
3.
Neurobiol Aging ; 58: 112-119, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28728117

RESUMO

This study reports the identification and characterization of markers of Alzheimer's disease (AD) in aged sheep (Ovis aries) as a preliminary step toward making a genetically modified large animal model of AD. Importantly, the sequences of key proteins involved in AD pathogenesis are highly conserved between sheep and human. The processing of the amyloid-ß (Aß) protein is conserved between sheep and human, and sheep Aß1-42/Aß1-40 ratios in cerebrospinal fluid (CSF) are also very similar to human. In addition, total tau and neurofilament light levels in CSF are comparable with those found in human. The presence of neurofibrillary tangles in aged sheep brain has previously been established; here, we report for the first time that plaques, the other pathologic hallmark of AD, are also present in the aged sheep brain. In summary, the biological machinery to generate the key neuropathologic features of AD is conserved between the human and sheep, making the sheep a good candidate for future genetic manipulation to accelerate the condition for use in pathophysiological discovery and therapeutic testing.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Animais Geneticamente Modificados , Modelos Animais de Doenças , Proteínas de Neurofilamentos/líquido cefalorraquidiano , Fragmentos de Peptídeos/líquido cefalorraquidiano , Proteínas tau/líquido cefalorraquidiano , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Animais , Biomarcadores/líquido cefalorraquidiano , Encéfalo/metabolismo , Encéfalo/patologia , Humanos , Emaranhados Neurofibrilares , Placa Amiloide/metabolismo , Placa Amiloide/patologia , Ovinos
4.
Sci Rep ; 7: 43030, 2017 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-28223686

RESUMO

The pronounced cachexia (unexplained wasting) seen in Huntington's disease (HD) patients suggests that metabolic dysregulation plays a role in HD pathogenesis, although evidence of metabolic abnormalities in HD patients is inconsistent. We performed metabolic profiling of plasma from presymptomatic HD transgenic and control sheep. Metabolites were quantified in sequential plasma samples taken over a 25 h period using a targeted LC/MS metabolomics approach. Significant changes with respect to genotype were observed in 89/130 identified metabolites, including sphingolipids, biogenic amines, amino acids and urea. Citrulline and arginine increased significantly in HD compared to control sheep. Ten other amino acids decreased in presymptomatic HD sheep, including branched chain amino acids (isoleucine, leucine and valine) that have been identified previously as potential biomarkers of HD. Significant increases in urea, arginine, citrulline, asymmetric and symmetric dimethylarginine, alongside decreases in sphingolipids, indicate that both the urea cycle and nitric oxide pathways are dysregulated at early stages in HD. Logistic prediction modelling identified a set of 8 biomarkers that can identify 80% of the presymptomatic HD sheep as transgenic, with 90% confidence. This level of sensitivity, using minimally invasive methods, offers novel opportunities for monitoring disease progression in HD patients.


Assuntos
Biomarcadores/metabolismo , Doença de Huntington/patologia , Metabolômica , Aminoácidos de Cadeia Ramificada/metabolismo , Animais , Animais Geneticamente Modificados/genética , Área Sob a Curva , Arginina/análogos & derivados , Arginina/metabolismo , Citrulina/metabolismo , Genótipo , Doença de Huntington/metabolismo , Doença de Huntington/veterinária , Modelos Logísticos , Curva ROC , Ovinos
5.
Sci Rep ; 6: 20681, 2016 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-26864449

RESUMO

Huntington's disease (HD) is a dominantly inherited, progressive neurodegenerative disorder caused by a CAG repeat expansion within exon 1 of HTT, encoding huntingtin. There are no therapies that can delay the progression of this devastating disease. One feature of HD that may play a critical role in its pathogenesis is metabolic disruption. Consequently, we undertook a comparative study of metabolites in our transgenic sheep model of HD (OVT73). This model does not display overt symptoms of HD but has circadian rhythm alterations and molecular changes characteristic of the early phase disease. Quantitative metabolite profiles were generated from the motor cortex, hippocampus, cerebellum and liver tissue of 5 year old transgenic sheep and matched controls by gas chromatography-mass spectrometry. Differentially abundant metabolites were evident in the cerebellum and liver. There was striking tissue-specificity, with predominantly amino acids affected in the transgenic cerebellum and fatty acids in the transgenic liver, which together may indicate a hyper-metabolic state. Furthermore, there were more strong pair-wise correlations of metabolite abundance in transgenic than in wild-type cerebellum and liver, suggesting altered metabolic constraints. Together these differences indicate a metabolic disruption in the sheep model of HD and could provide insight into the presymptomatic human disease.


Assuntos
Cerebelo/metabolismo , Hipocampo/metabolismo , Doença de Huntington/metabolismo , Fígado/metabolismo , Metaboloma , Córtex Motor/metabolismo , Aminoácidos/metabolismo , Animais , Animais Geneticamente Modificados , Doenças Assintomáticas , Cerebelo/fisiopatologia , Ritmo Circadiano , Modelos Animais de Doenças , Ácidos Graxos/metabolismo , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Hipocampo/fisiopatologia , Humanos , Doença de Huntington/fisiopatologia , Fígado/fisiopatologia , Masculino , Córtex Motor/fisiopatologia , Especificidade de Órgãos , Carneiro Doméstico
6.
PLoS One ; 10(7): e0132331, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26161747

RESUMO

Variant late-infantile Batten disease is a neuronal ceroid lipofuscinosis caused by mutations in CLN6. It is a recessive genetic lysosomal storage disease characterised by progressive neurodegeneration. It starts insidiously and leads to blindness, epilepsy and dementia in affected children. Sheep that are homozygous for a natural mutation in CLN6 have an ovine form of Batten disease Here, we used in vivo magnetic resonance imaging to track brain changes in 4 unaffected carriers and 6 affected Batten disease sheep. We scanned each sheep 4 times, between 17 and 22 months of age. Cortical atrophy in all sheep was pronounced at the baseline scan in all affected Batten disease sheep. Significant atrophy was also present in other brain regions (caudate, putamen and amygdala). Atrophy continued measurably in all of these regions during the study. Longitudinal MRI in sheep was sensitive enough to measure significant volume changes over the relatively short study period, even in the cortex, where nearly 40% of volume was already lost at the start of the study. Thus longitudinal MRI could be used to study the dynamics of progression of neurodegenerative changes in sheep models of Batten disease, as well as to assess therapeutic efficacy.


Assuntos
Encéfalo/patologia , Progressão da Doença , Imagem por Ressonância Magnética , Proteínas de Membrana/genética , Lipofuscinoses Ceroides Neuronais/patologia , Animais , Atrofia , Peso Corporal , Feminino , Masculino , Tamanho do Órgão , Fenótipo , Ovinos
7.
Hum Mol Genet ; 23(13): 3375-83, 2014 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-24488771

RESUMO

Insidious changes in behaviour herald the onset of progressive neurodegenerative disorders such as Huntington's disease (HD), sometimes years before overt symptoms are seen. Sleep and circadian disturbances are particularly disruptive symptoms in patients with neurological disorders, but they are difficult to measure in humans. Here we studied circadian behaviour in transgenic HD sheep expressing the full-length human huntingtin protein with an expanded CAG repeat mutation in the juvenile range. Young HD sheep with no other symptoms exhibited circadian behavioural abnormalities that worsened with age. The most obvious change was a disturbed evening behaviour reminiscent of 'sundowning' that is seen in some patients with dementia. There were no structural abnormalities seen with magnetic resonance imaging, even in 5-year-old HD sheep. Interestingly, detection of the circadian abnormalities depended upon their social grouping. Abnormalities emerged in sheep kept in an 'HD-only' flock, whereas the behaviour of HD sheep kept mixed with normal sheep was relatively normal. Sleep-wake abnormalities in HD patients are also likely to be hidden, and may precede overt symptoms by many years. Sleep disruption has deleterious effects, even in normal people. The knock-on effects of sleep-wake disturbance may exacerbate, or even cause symptoms such as irritability and depression that are common in early stage HD patients. HD sheep will be useful models for probing the mechanisms underlying circadian behavioural disorder in HD.


Assuntos
Ritmo Circadiano/fisiologia , Doença de Huntington/fisiopatologia , Meio Social , Animais , Ovinos
8.
J Huntingtons Dis ; 2(3): 279-95, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-25062676

RESUMO

BACKGROUND: Huntington's disease is a neurodegenerative disorder, typically with clinical manifestations in adult years, caused by an expanded polyglutamine-coding repeat in HTT. There are no treatments that delay or prevent the onset or progression of this devastating disease. OBJECTIVE AND METHODS: In order to study its pre-symptomatic molecular progression and provide a large mammalian model for determining natural history of the disease and for therapeutic testing, we generated and previously reported on lines of transgenic sheep carrying a full length human HTT cDNA transgene, with expression driven by a minimal HTT promoter. We report here further characterization of our preferred line, OVT73. RESULTS: This line reliably expresses the expanded human huntingtin protein at modest, but readily detectable levels throughout the brain, including the striatum and cortex. Transmission of the 73 unit glutamine coding repeat was relatively stable over three generations. At the first time-point of a longitudinal study, animals sacrificed at 6 months (7 transgenic, 7 control) showed reduced striatum GABAA α1 receptor, and globus pallidus leu-enkephalin immunoreactivity. Two of three 18 month old animals sacrificed revealed cortical neuropil aggregates. Furthermore, neuronal intranuclear inclusions were identified in the piriform cortex of a single 36 month old animal in addition to cortical neuropil aggregates. CONCLUSIONS: Taken together, these data indicate that the OVT73 transgenic sheep line will progressively reveal early HD pathology and allow therapeutic testing over a period of time relevant to human patients.


Assuntos
Animais Geneticamente Modificados , Córtex Cerebral/patologia , Modelos Animais de Doenças , Doença de Huntington/patologia , Carneiro Doméstico/genética , Animais , Humanos , Proteína Huntingtina , Corpos de Inclusão Intranuclear/patologia , Proteínas do Tecido Nervoso/genética
9.
Nat Genet ; 44(4): 390-7, S1, 2012 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-22388000

RESUMO

We defined the genetic landscape of balanced chromosomal rearrangements at nucleotide resolution by sequencing 141 breakpoints from cytogenetically interpreted translocations and inversions. We confirm that the recently described phenomenon of 'chromothripsis' (massive chromosomal shattering and reorganization) is not unique to cancer cells but also occurs in the germline, where it can resolve to a relatively balanced state with frequent inversions. We detected a high incidence of complex rearrangements (19.2%) and substantially less reliance on microhomology (31%) than previously observed in benign copy-number variants (CNVs). We compared these results to experimentally generated DNA breakage-repair by sequencing seven transgenic animals, revealing extensive rearrangement of the transgene and host genome with similar complexity to human germline alterations. Inversion was the most common rearrangement, suggesting that a combined mechanism involving template switching and non-homologous repair mediates the formation of balanced complex rearrangements that are viable, stably replicated and transmitted unaltered to subsequent generations.


Assuntos
Quebra Cromossômica , Reparo do DNA por Junção de Extremidades/genética , Rearranjo Gênico , Mutação em Linhagem Germinativa , Animais , Animais Geneticamente Modificados , Inversão Cromossômica , Humanos , Dados de Sequência Molecular , Neoplasias/genética , Análise de Sequência com Séries de Oligonucleotídeos , Análise de Sequência de DNA , Translocação Genética
10.
Int J Biol Sci ; 8(2): 258-64, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22298953

RESUMO

Most protein in hair and wool is of two broad types: keratin intermediate filament-forming proteins (commonly known as keratins) and keratin-associated proteins (KAPs). Keratin nomenclature was reviewed in 2006, but the KAP nomenclature has not been revised since 1993. Recently there has been an increase in the number of KAP genes (KRTAPs) identified in humans and other species, and increasingly reports of variation in these genes. We therefore propose that an updated naming system is needed to accommodate the complexity of the KAPs. It is proposed that the system is founded in the previous nomenclature, but with the abbreviation sp-KAPm-nL*x for KAP proteins and sp-KRTAPm-n(p/L)*x for KAP genes. In this system "sp" is a unique letter-based code for different species as described by the protein knowledge-based UniProt. "m" is a number identifying the gene or protein family, "n" is a constituent member of that family, "p" signifies a pseudogene if present, "L" if present signifies "like" and refers to a temporary "place-holder" until the family is confirmed and "x" signifies a genetic variant or allele. We support the use of non-italicised text for the proteins and italicised text for the genes. This nomenclature is not that different to the existing system, but it includes species information and also describes genetic variation if identified, and hence is more informative. For example, GenBank sequence JN091630 would historically have been named KRTAP7-1 for the gene and KAP7-1 for the protein, but with the proposed nomenclature would be SHEEP-KRTAP7-1*A and SHEEP-KAP7-1*A for the gene and protein respectively. This nomenclature will facilitate more efficient storage and retrieval of data and define a common language for the KAP proteins and genes from all mammalian species.


Assuntos
Queratinas/classificação , Terminologia como Assunto , Animais , Regulação da Expressão Gênica/fisiologia , Especificidade da Espécie
11.
Hum Mol Genet ; 19(10): 1873-82, 2010 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-20154343

RESUMO

Huntington's disease (HD) is an inherited autosomal dominant neurodegenerative disorder caused by an expansion of a CAG trinucleotide repeat in the huntingtin (HTT) gene [Huntington's Disease Collaborative Research Group (1993) A novel gene containing a trinucleotide repeat that is expanded and unstable on Huntington's disease chromosomes. The Huntington's Disease Collaborative Research Group. Cell, 72, 971-983]. Despite identification of the gene in 1993, the underlying life-long disease process and effective treatments to prevent or delay it remain elusive. In an effort to fast-track treatment strategies for HD into clinical trials, we have developed a new large-animal HD transgenic ovine model. Sheep, Ovis aries L., were selected because the developmental pattern of the ovine basal ganglia and cortex (the regions primarily affected in HD) is similar to the analogous regions of the human brain. Microinjection of a full-length human HTT cDNA containing 73 polyglutamine repeats under the control of the human promotor resulted in six transgenic founders varying in copy number of the transgene. Analysis of offspring (at 1 and 7 months of age) from one of the founders showed robust expression of the full-length human HTT protein in both CNS and non-CNS tissue. Further, preliminary immunohistochemical analysis demonstrated the organization of the caudate nucleus and putamen and revealed decreased expression of medium size spiny neuron marker DARPP-32 at 7 months of age. It is anticipated that this novel transgenic animal will represent a practical model for drug/clinical trials and surgical interventions especially aimed at delaying or preventing HD initiation. New sequence accession number for ovine HTT mRNA: FJ457100.


Assuntos
Animais Geneticamente Modificados/genética , Modelos Animais de Doenças , Doença de Huntington/genética , Ovinos/genética , Animais , Gânglios da Base/metabolismo , Gânglios da Base/patologia , Cromossomos de Mamíferos/genética , Fosfoproteína 32 Regulada por cAMP e Dopamina/metabolismo , Feminino , Efeito Fundador , Humanos , Proteína Huntingtina , Masculino , Proteínas do Tecido Nervoso/genética , Proteínas Nucleares/genética , Linhagem , Receptor CB1 de Canabinoide/metabolismo , Transgenes/genética
12.
Differentiation ; 77(3): 307-16, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19272529

RESUMO

The catalogue of hair keratin intermediate filaments (KIFs) and keratin-associated proteins (KAPs) present in wool follicles is incomplete. The full coding sequences for three novel sheep KIFs (KRT27, KRT35 and KRT38) and one KAP (KRTAP4-3) were established in this study. Spatial expression patterns of these and other genes (KRT31, KRT85, KRTAP6-1 and trichohyalin) were determined by in situ hybridisation in wool follicles at synchronised stages of growth. Transcription proceeded in the order: trichohyalin, KRT27, KRT85, KRT35, KRT31, KRT38, KRTAP6-1 and KRTAP4-3, as determined by increasing distance of their expression zones from the germinal matrix in anagen follicles. Expression became gradually more restricted to the lower follicle during follicle regression (catagen), and ceased during dormancy (telogen). Some genes (KRT27, KRT31, KRT85 and KRTAP6-1), but not others, were expressed in cortical cells forming the brush-end, indicating specific requirements for the formation of this anchoring structure. The resumption of keratin expression was observed only in later stages of follicle reactivation (proanagen). KIF expression patterns in primary wool follicles showed general resemblance to their human homologues but with some unique features. Consistent differences in localisation between primary and secondary wool follicles were observed. Asymmetrical expression of KRT27, KRT31, KRT35, KRT85 and trichohyalin genes in secondary follicles were associated with bulb deflection and follicle curvature, suggesting a role in the determination of follicle and fibre morphology.


Assuntos
Regulação da Expressão Gênica , Folículo Piloso/metabolismo , Filamentos Intermediários/genética , Filamentos Intermediários/metabolismo , Queratinas , Ovinos/metabolismo , , Animais , Sequência de Bases , Perfilação da Expressão Gênica , Folículo Piloso/crescimento & desenvolvimento , Queratinas/genética , Queratinas/metabolismo , Dados de Sequência Molecular , RNA Mensageiro/metabolismo , Ovinos/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA