RESUMO
Huntingtin (HTT)-lowering therapies show great promise in treating Huntington's disease. We have developed a microRNA targeting human HTT that is delivered in an adeno-associated serotype 5 viral vector (AAV5-miHTT), and here use animal behaviour, MRI, non-invasive proton magnetic resonance spectroscopy and striatal RNA sequencing as outcome measures in preclinical mouse studies of AAV5-miHTT. The effects of AAV5-miHTT treatment were evaluated in homozygous Q175FDN mice, a mouse model of Huntington's disease with severe neuropathological and behavioural phenotypes. Homozygous mice were used instead of the more commonly used heterozygous strain, which exhibit milder phenotypes. Three-month-old homozygous Q175FDN mice, which had developed acute phenotypes by the time of treatment, were injected bilaterally into the striatum with either formulation buffer (phosphate-buffered saline + 5% sucrose), low dose (5.2 × 109 genome copies/mouse) or high dose (1.3 × 1011 genome copies/mouse) AAV5-miHTT. Wild-type mice injected with formulation buffer served as controls. Behavioural assessments of cognition, T1-weighted structural MRI and striatal proton magnetic resonance spectroscopy were performed 3 months after injection, and shortly afterwards the animals were sacrificed to collect brain tissue for protein and RNA analysis. Motor coordination was assessed at 1-month intervals beginning at 2 months of age until sacrifice. Dose-dependent changes in AAV5 vector DNA level, miHTT expression and mutant HTT were observed in striatum and cortex of AAV5-miHTT-treated Huntington's disease model mice. This pattern of microRNA expression and mutant HTT lowering rescued weight loss in homozygous Q175FDN mice but did not affect motor or cognitive phenotypes. MRI volumetric analysis detected atrophy in four brain regions in homozygous Q175FDN mice, and treatment with high dose AAV5-miHTT rescued this effect in the hippocampus. Like previous magnetic resonance spectroscopy studies in Huntington's disease patients, decreased total N-acetyl aspartate and increased myo-inositol levels were found in the striatum of homozygous Q175FDN mice. These neurochemical findings were partially reversed with AAV5-miHTT treatment. Striatal transcriptional analysis using RNA sequencing revealed mutant HTT-induced changes that were partially reversed by HTT lowering with AAV5-miHTT. Striatal proton magnetic resonance spectroscopy analysis suggests a restoration of neuronal function, and striatal RNA sequencing analysis shows a reversal of transcriptional dysregulation following AAV5-miHTT in a homozygous Huntington's disease mouse model with severe pathology. The results of this study support the use of magnetic resonance spectroscopy in HTT-lowering clinical trials and strengthen the therapeutic potential of AAV5-miHTT in reversing severe striatal dysfunction in Huntington's disease.
Assuntos
Doença de Huntington , MicroRNAs , Humanos , Animais , Camundongos , Lactente , Doença de Huntington/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Corpo Estriado/metabolismo , Encéfalo/patologia , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Modelos Animais de DoençasRESUMO
While Huntington disease (HD) is caused solely by a polyglutamine expansion in the huntingtin gene, environmental factors can influence HD onset and progression. Here, we review studies linking environment and HD in both humans and animal models. In HD patients, we find that: (i) an active lifestyle associates with both a delayed age at onset of HD and a decreased severity of symptoms, (ii) applying physical exercise and behavioral therapies in small cohorts of HD subjects indicate promising effects on the HD symptomatology, (iii) Mediterranean diet correlates with lower motor impairment, and treatments based on omega-3 fatty acids improve motor function , whereas (iv) increased cortisol levels associate with specific HD symptoms. In animal models, in line with the evidence in humans, physical exercise, environmental enrichment and different types of dietary intervention ameliorate or delay several HD phenotypes. In contrast, stress appears to be involved in the HD pathogenesis, and HD mice present increased stress sensitivity. Importantly, studies in animal models have uncovered several molecular factors mediating environmental effects on HD associated neuropathology. However, the influence of the environment on several key HD mechanisms as well as the underlying regulatory factors remain to be explored. Given the role of epigenetic factors and modifications in the interplay between environment and genes, the exploration of their role as mechanisms underlying the environmental action in HD is a promising avenue for both our fundamental understanding of the disease and as a potential for therapy.
Assuntos
Meio Ambiente , Doença de Huntington , Animais , Modelos Animais de Doenças , Humanos , Proteína Huntingtina , Doença de Huntington/genética , Doença de Huntington/patologia , Doença de Huntington/terapia , Camundongos , Camundongos TransgênicosRESUMO
Ginseng is a popular herbal medicine and known to have protective and therapeutic effects in various diseases. Ginsenosides are active gradients representing the diverse pharmacological efficacy of ginseng. Huntington's disease (HD) is incurable genetic disorder associated with mutant huntingtin (mHtt) aggregation in the central nervous system. This study was conducted to investigate the effects of ginsenoside Rg3 and Rf on mHtt aggregation, cell viability, mitochondrial function, and apoptotic molecules on HD model. To investigate the effect of ginsenosides on HD, neural stem cells were isolated from the R6/2 mouse brain and used as a cellular model of HD. Nuclear aggregation of mHtt was measured by immunocytochemistry, and expressions of mitochondrial biogenesis and apoptotic molecules were investigated by western blot. As a result, the number of mHtt aggregates positive cells has decreased by ginsenoside Rg3 and Rf treatment in cellular model of HD. Mitochondrial biogenesis-related molecules such as PGC-1α and phosphorylated CREB were increased or showed increased tendency by ginsenoside Rg3 and Rf. Apoptotic molecules, p53, Bax, and cleaved caspase-3, were down-regulated by treatment of ginsenoside Rg3 and Rf. In addition, Lysotracker staining result showed that cellular lysosomal content was reduced by ginsenoside Rg3 and Rf. Given that ginsenoside Rg3 and Rf have the potential to reduce mHtt aggregation and cellular apoptosis, these ginsenosides can be possible therapeutic candidates for treating HD phenotypes.
Assuntos
Ginsenosídeos/farmacologia , Proteína Huntingtina/genética , Doença de Huntington/tratamento farmacológico , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Apoptose/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Doença de Huntington/genética , Doença de Huntington/patologia , Proteínas Mutantes/genética , Células-Tronco Neurais/efeitos dos fármacosRESUMO
Huntington's disease (HD) is a neurodegenerative disorder caused by a dominant CAG-repeat expansion in the huntingtin gene. Microglial activation is a key feature of HD pathology, and is present before clinical disease onset. The kynurenine pathway (KP) of tryptophan degradation is activated in HD, and is thought to contribute to disease progression. Indoleamine-2,3-dioxygenase (IDO) catalyzes the first step in this pathway; this and other pathway enzymes reside with microglia. While HD brain microglia accumulate iron, the role of iron in promoting microglial activation and KP activity is unclear. Here we utilized the neonatal iron supplementation model to investigate the relationship between iron, microglial activation and neurodegeneration in adult HD mice. We show in the N171-82Q mouse model of HD microglial morphologic changes consistent with immune activation. Neonatal iron supplementation in these mice promoted neurodegeneration and resulted in additional microglial activation in adults as determined by increased soma volume and decreased process length. We further demonstrate that iron activates IDO, both in brain lysates and purified recombinant protein (EC50 = 1.24 nM). Brain IDO activity is increased by HD. Neonatal iron supplementation further promoted IDO activity in cerebral cortex, altered KP metabolite profiles, and promoted HD neurodegeneration as measured by brain weights and striatal volumes. Our results demonstrate that dietary iron is an important activator of microglia and the KP pathway in this HD model, and that this occurs in part through a direct effect on IDO. The findings are relevant to understanding how iron promotes neurodegeneration in HD.
Assuntos
Encéfalo/patologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Proteína Huntingtina/genética , Doença de Huntington/patologia , Indolamina-Pirrol 2,3,-Dioxigenase/metabolismo , Ferro/farmacologia , Microglia/patologia , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Modelos Animais de Doenças , Doença de Huntington/etiologia , Doença de Huntington/metabolismo , Cinurenina/metabolismo , Camundongos , Camundongos Transgênicos , Microglia/efeitos dos fármacos , Microglia/metabolismoRESUMO
Impairment of proteostasis network is one of the characteristic features of many age-related neurodegenerative disorders including autosomal dominantly inherited Huntington's disease (HD). In HD, N-terminal portion of mutant huntingtin protein containing expanded polyglutamine repeats accumulates as inclusion bodies and leads to progressive deterioration of various cellular functioning including proteostasis network. Here we report that Withaferin A (a small bioactive molecule derived from Indian medicinal plant, Withania somnifera) partially rescues defective proteostasis by activating heat shock response (HSR) and delays the disease progression in a HD mouse model. Exposure of Withaferin A activates HSF1 and induces the expression of HSP70 chaperones in an in vitro cell culture system and also suppresses mutant huntingtin aggregation in a cellular model of HD. Withaferin A treatment to HD mice considerably increased their lifespan as well as restored progressive motor behavioral deficits and declined body weight. Biochemical studies confirmed the activation of HSR and global decrease in mutant huntingtin aggregates load accompanied with improvement of striatal function in Withaferin A-treated HD mouse brain. Withaferin A-treated HD mice also exhibit significant decrease in inflammatory processes as evident from the decreased microglial activation. These results indicate immense potential of Withaferin A for the treatment of HD and related neurodegenerative disorders involving protein misfolding and aggregation.
Assuntos
Modelos Animais de Doenças , Progressão da Doença , Proteínas de Choque Térmico HSP70/biossíntese , Doença de Huntington/metabolismo , Vitanolídeos/uso terapêutico , Animais , Relação Dose-Resposta a Droga , Proteínas de Choque Térmico HSP70/genética , Humanos , Proteína Huntingtina/biossíntese , Proteína Huntingtina/genética , Doença de Huntington/tratamento farmacológico , Doença de Huntington/genética , Camundongos , Camundongos Endogâmicos CBA , Camundongos Transgênicos , Vitanolídeos/farmacologiaRESUMO
Huntington's disease (HD) is a neurodegenerative disorder characterized by accumulation of mutant huntingtin protein and significant loss of neurons in striatum and cortex. Along with motor difficulties, the HD patients also manifest anxiety and loss of cognition. Unfortunately, the clinically approved drugs only offer symptomatic relief and are not free from side effects. This study underlines the importance of glyceryl tribenzoate (GTB), an FDA-approved food flavoring ingredient, in alleviating HD pathology in transgenic N171-82Q mouse model. Oral administration of GTB significantly reduced mutant huntingtin level in striatum, motor cortex as well as hippocampus and increased the integrity of viable neurons. Furthermore, we found the presence of sodium benzoate (NaB), a FDA-approved drug for urea cycle disorders and glycine encephalopathy, in the brain of GTB-fed HD mice. Accordingly, NaB administration also markedly decreased huntingtin level in striatum and cortex. Glial activation is found to coincide with neuronal death in affected regions of HD brains. Interestingly, both GTB and NaB treatment suppressed activation of glial cells and inflammation in the brain. Finally, neuroprotective effect of GTB and NaB resulted in improved motor performance of HD mice. Collectively, these results suggest that GTB and NaB may be repurposed for HD.
Assuntos
Benzoatos/administração & dosagem , Aromatizantes/farmacologia , Conservantes de Alimentos/farmacologia , Proteína Huntingtina/efeitos dos fármacos , Doença de Huntington/metabolismo , Córtex Motor/efeitos dos fármacos , Neostriado/efeitos dos fármacos , Benzoato de Sódio/farmacologia , Administração Oral , Animais , Benzoatos/farmacologia , Ácido Benzoico/farmacologia , Análise da Marcha , Força da Mão , Humanos , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Doença de Huntington/genética , Doença de Huntington/fisiopatologia , Camundongos , Camundongos Transgênicos , Córtex Motor/metabolismo , Neostriado/metabolismo , Teste de Campo Aberto , Teste de Desempenho do Rota-Rod , Benzoato de Sódio/metabolismoRESUMO
Alzheimer's disease (AD) is defined by progressive neurodegeneration, with oligomerization and aggregation of amyloid-ß peptides (Aß) playing a pivotal role in its pathogenesis. In recent years, the yeast Saccharomyces cerevisiae has been successfully used to clarify the roles of different human proteins involved in neurodegeneration. Here, we report a genome-wide synthetic genetic interaction array to identify toxicity modifiers of Aß42, using yeast as the model organism. We find that FMN1, the gene encoding riboflavin kinase, and its metabolic product flavin mononucleotide (FMN) reduce Aß42 toxicity. Classic experimental analyses combined with RNAseq show the effects of FMN supplementation to include reducing misfolded protein load, altering cellular metabolism, increasing NADH/(NADH + NAD+) and NADPH/(NADPH + NADP+) ratios and increasing resistance to oxidative stress. Additionally, FMN supplementation modifies Htt103QP toxicity and α-synuclein toxicity in the humanized yeast. Our findings offer insights for reducing cytotoxicity of Aß42, and potentially other misfolded proteins, via FMN-dependent cellular pathways.
Assuntos
Peptídeos beta-Amiloides/metabolismo , Peptídeos beta-Amiloides/toxicidade , Mononucleotídeo de Flavina/metabolismo , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/toxicidade , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Doença de Alzheimer/etiologia , Doença de Alzheimer/metabolismo , Genes Sintéticos , Genoma Fúngico , Humanos , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Modelos Genéticos , Mutação , Oxirredução , Oxirredutases/genética , Oxirredutases/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Dobramento de Proteína , Proteólise , RNA-Seq , Riboflavina/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , alfa-Sinucleína/genética , alfa-Sinucleína/metabolismoRESUMO
Objectives: Green tea infusion contains a complex mixture of polyphenolic compounds that were shown to provide health benefits. It was previously demonstrated that (-)-epigallocatechin-3-gallate, one of the major polyphenols present in green tea, has a suppressing effect on various aspects of pathogenesis in models of Huntington's disease (HD), an inherited neurodegenerative disorder. In this study, we aimed to investigate, whether green tea infusion prepared as for human consumption has similar positive effects.Methods: We used a transgenic Drosophila model of HD to study the effects of green tea on mutant Huntingtin induced phenotypes. We tested the effects of green tea infusion on mutant Huntingtin induced neurodegeneration, impaired motor performance, reduced viability and lifespan by pseudopupil assay, climbing assay, eclosion and survival tests, respectively. We used immunoblots to measure Huntingtin protein levels and tested generic health benefits of green tea by longevity analysis.Results: We found that green tea supplementation reduced mutant Huntingtin induced neurodegeneration in Drosophila and positively impacted the longevity of mutant Huntingtin expressing flies. However, green tea did not rescue reduced viability of Drosophila expressing mutant Huntingtin or increased longevity of wild-type fruit flies.Discussion: Our results indicate that green tea consumption might have a modest positive effect on symptoms of HD.
Assuntos
Animais Geneticamente Modificados , Drosophila/genética , Proteína Huntingtina/genética , Degeneração Neural/tratamento farmacológico , Extratos Vegetais/administração & dosagem , Chá , Animais , Feminino , Expressão Gênica , Proteína Huntingtina/análise , Doença de Huntington/tratamento farmacológico , Doença de Huntington/fisiopatologia , Longevidade/efeitos dos fármacos , MasculinoRESUMO
Accumulation of mutant proteins is a major cause of many diseases (collectively called proteopathies), and lowering the level of these proteins can be useful for treatment of these diseases. We hypothesized that compounds that interact with both the autophagosome protein microtubule-associated protein 1A/1B light chain 3 (LC3)1 and the disease-causing protein may target the latter for autophagic clearance. Mutant huntingtin protein (mHTT) contains an expanded polyglutamine (polyQ) tract and causes Huntington's disease, an incurable neurodegenerative disorder2. Here, using small-molecule-microarray-based screening, we identified four compounds that interact with both LC3 and mHTT, but not with the wild-type HTT protein. Some of these compounds targeted mHTT to autophagosomes, reduced mHTT levels in an allele-selective manner, and rescued disease-relevant phenotypes in cells and in vivo in fly and mouse models of Huntington's disease. We further show that these compounds interact with the expanded polyQ stretch and could lower the level of mutant ataxin-3 (ATXN3), another disease-causing protein with an expanded polyQ tract3. This study presents candidate compounds for lowering mHTT and potentially other disease-causing proteins with polyQ expansions, demonstrating the concept of lowering levels of disease-causing proteins using autophagosome-tethering compounds.
Assuntos
Alelos , Avaliação Pré-Clínica de Medicamentos/métodos , Proteína Huntingtina/antagonistas & inibidores , Proteína Huntingtina/genética , Proteínas Mutantes/antagonistas & inibidores , Proteínas Mutantes/genética , Mutação/genética , Animais , Ataxina-3/genética , Autofagossomos/metabolismo , Autofagia , Modelos Animais de Doenças , Proteínas de Drosophila/antagonistas & inibidores , Proteínas de Drosophila/química , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Feminino , Humanos , Proteína Huntingtina/química , Proteína Huntingtina/metabolismo , Masculino , Camundongos , Proteínas Associadas aos Microtúbulos/genética , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Mutação/efeitos dos fármacos , Neurônios/citologia , Peptídeos/genética , Fenótipo , Reprodutibilidade dos TestesRESUMO
Huntington's disease (HD) is an incurable disease with progressive loss of neural function, which is influenced by epigenetic, oxidative stress, metabolic, and nutritional factors. Targeting inhibition of huntingtin protein aggregation is a strategy for HD therapy, but the efficacy is unsatisfactory. Studies found that selenium (Se) levels in the brain are insufficient for HD disease individuals, while improvement in Se homeostasis in the brain may attenuate neuronal loss and dysfunction. In this study, we applied selenium nanoparticles (NPs) (Nano-Se) for the HD disease therapy by regulating HD-related neurodegeneration and cognitive decline based on transgenic HD models of Caenorhabditis elegans (C. elegans). At low dosages, Nano-Se NPs significantly reduced neuronal death, relieved behavioral dysfunction, and protected C. elegans from damages in stress conditions. The molecular mechanism further revealed that Nano-Se attenuated oxidative stress, inhibited the aggregation of huntingtin proteins, and downregulated the expression of histone deacetylase family members at mRNA levels. The results suggested that Nano-Se has great potential for Huntington's disease therapy. In conclusion, the mechanism about how Nano-Se NPs protect from damages in stress conditions and how they repair neural functions will benefit HD disease therapy. This study will also guide rational design of Nano-Se NPs or other selenium compounds to improve HD therapy in the future.
Assuntos
Caenorhabditis elegans , Doença de Huntington , Nanopartículas , Estresse Oxidativo/efeitos dos fármacos , Selênio , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Morte Celular/efeitos dos fármacos , Modelos Animais de Doenças , Humanos , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Doença de Huntington/tratamento farmacológico , Doença de Huntington/genética , Doença de Huntington/metabolismo , Doença de Huntington/patologia , Nanomedicina , Nanopartículas/química , Nanopartículas/uso terapêutico , Neurônios/metabolismo , Neurônios/patologia , Selênio/química , Selênio/farmacologiaRESUMO
BACKGROUND: According to Compendium of Materia Medica, Gastrodia elata (GE) Blume as a top grade and frequently prescribed herbal medicine has been used in treating dizziness, headaches, and epilepsy, indicating a neuroprotective effect. Because GE is capable of suppressing a hyperactive liver and thus calming endogenous wind, and because Huntington's disease (HD) can be classified as a phenomenon of disturbed liver wind, it is suggested that GE might be beneficial in treating HD. However, although current studies support GE for the prevention of diverse neurodegenerations such as HD, its detailed mechanisms remain elusive. PURPOSE: To investigate the molecular mechanism of GE in preventing HD by focusing on mitochondrial morphology, which is highly associated with HD etiology and thus proposed as a therapeutic target of neurodegenerations. STUDY DESIGN/METHODS: The overexpression of the mutant huntingtin (mHTT) gene in rat pheochromocytoma (PC12) cells was used as an in vitro cell model of HD. A filter retardation assay was applied to measure protein aggregations during HTT expression. Cotransfection with mitochondrial fusion and fission genes was used to test their relationships with HTT aggregates by monitoring with a confocal laser scanning microscope and filter retardation assay. Western blot analysis was used to estimate protein expression under different drug treatments or cotransfections with other related genes. RESULTS: The overexpression of mutant but not normal HTT genes significantly resulted in protein aggregations in PC12 cells. GE dose-dependently attenuated mHTT-induced protein aggregations and free radical formations. GE significantly reversed mHTT-induced mitochondrial fragmentation and dysregulation of mitochondrial fusion and fission molecules. The overexpression of mitochondrial fusion genes attenuated mHTT-induced protein aggregations. Further, Mdivi-1, a DRP1 fission molecule inhibitor, significantly reversed mHTT-induced protein aggregations and mitochondrial fragmentation. CONCLUSION: GE attenuated mHTT aggregations through the control of mitochondrial fusion and the fission pathway.
Assuntos
Gastrodia , Proteína Huntingtina/metabolismo , Doença de Huntington/metabolismo , Mitocôndrias/efeitos dos fármacos , Extratos Vegetais/farmacologia , Agregados Proteicos/efeitos dos fármacos , Animais , Proteína Huntingtina/genética , Doença de Huntington/tratamento farmacológico , Mitocôndrias/metabolismo , Mutação , Células PC12 , Fitoterapia , Extratos Vegetais/uso terapêutico , RatosRESUMO
Edible berries are considered to be among nature's treasure chests as they contain a large number of (poly)phenols with potentially health-promoting properties. However, as berries contain complex (poly)phenol mixtures, it is challenging to associate any interesting pharmacological activity with a single compound. Thus, identification of pharmacologically interesting phenols requires systematic analyses of berry extracts. Here, raspberry (Rubus idaeus, var Prestige) extracts were systematically analyzed to identify bioactive compounds against pathological processes of neurodegenerative diseases. Berry extracts were tested on different Saccharomyces cerevisiae strains expressing disease proteins associated with Alzheimer's, Parkinson's, or Huntington's disease, or amyotrophic lateral sclerosis. After identifying bioactivity against Huntington's disease, the extract was fractionated and the obtained fractions were tested in the yeast model, which revealed that salidroside, a glycosylated phenol, displayed significant bioactivity. Subsequently, a metabolic route to salidroside was reconstructed in S cerevisiae and Corynebacterium glutamicum The best-performing S cerevisiae strain was capable of producing 2.1 mm (640 mg L-1) salidroside from Glc in shake flasks, whereas an engineered C glutamicum strain could efficiently convert the precursor tyrosol to salidroside, accumulating up to 32 mm (9,700 mg L-1) salidroside in bioreactor cultivations (yield: 0.81 mol mol-1). Targeted yeast assays verified that salidroside produced by both organisms has the same positive effects as salidroside of natural origin.
Assuntos
Glucosídeos/biossíntese , Proteína Huntingtina/química , Doença de Huntington/metabolismo , Extratos Vegetais/química , Rubus/química , Vias Biossintéticas , Fracionamento Químico , Glucosídeos/química , Glucosídeos/metabolismo , Modelos Biológicos , Fenóis/química , Fenóis/metabolismo , Extratos Vegetais/isolamento & purificação , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismoRESUMO
The 25 years since the identification of the gene responsible for Huntington disease (HD) have stood witness to profound discoveries about the nature of the disease and its pathogenesis. Despite this progress, however, the development of disease-modifying therapies has thus far been slow. Preclinical validation of the therapeutic potential of disrupted pathways in HD has led to the advancement of pharmacological agents, both novel and repurposed, for clinical evaluation. The most promising therapeutic approaches include huntingtin (HTT) lowering and modification as well as modulation of neuroinflammation and synaptic transmission. With clinical trials for many of these approaches imminent or currently ongoing, the coming years are promising not only for HD but also for more prevalent neurodegenerative disorders, such as Alzheimer and Parkinson disease, in which many of these pathways have been similarly implicated.
Assuntos
Doença de Huntington/tratamento farmacológico , Preparações Farmacêuticas/administração & dosagem , Animais , Ensaios Clínicos como Assunto , Avaliação Pré-Clínica de Medicamentos , Humanos , Proteína Huntingtina/metabolismo , Doença de Huntington/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
Huntington's disease (HD) is an autosomal dominant neurodegenerative disease which has no effective treatment and is characterized by psychiatric disorders, motor alterations, and dementia, with the cognitive deficits representing a devastating aspect of the disorder. Oxidative stress and elevated levels of lipid peroxidation (LPO) products are found in mouse models and patients with HD, suggesting that strategies to reduce LPO may be beneficial in HD. In contrast with traditional antioxidants, substituting hydrogen with deuterium at bis-allylic sites in polyunsaturated fatty acids (D-PUFA) decreases the rate-limiting initiation step of PUFA autoxidation, a strategy that has shown benefits in other neurodegenerative diseases. Here, we investigated the effect of D-PUFA treatment in a knock-in mouse model of HD (Q140) which presents motor deficits and neuropathology from a few months of age, and progressive cognitive decline. Q140 knock-in mice were fed a diet containing either D- or H-PUFAs for 5 months starting at 1 month of age. D-PUFA treatment significantly decreased F2 -isoprostanes in the striatum by approximately 80% as compared to H-PUFA treatment and improved performance in novel object recognition tests, without significantly changing motor deficits or huntingtin aggregation. Therefore, D-PUFA administration represents a promising new strategy to broadly reduce rates of LPO, and may be useful in improving a subset of the core deficits in HD.
Assuntos
Disfunção Cognitiva/dietoterapia , Deutério/farmacologia , Doença de Huntington/etiologia , Ácido Linoleico/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Disfunção Cognitiva/metabolismo , Deutério/química , Suplementos Nutricionais , Modelos Animais de Doenças , Ácidos Graxos Insaturados/química , Ácidos Graxos Insaturados/farmacologia , Feminino , Proteína Huntingtina/genética , Ácido Linoleico/química , Masculino , Camundongos Transgênicos , Atividade Motora/efeitos dos fármacosRESUMO
Accumulation of ubiquitinated protein aggregates is a common pathology associated with a number of neurodegenerative diseases and selective autophagy plays a critical role in their elimination. Although aging-related decreases in protein degradation properties may enhance protein aggregation, it remains unclear whether proteasome dysfunction is indispensable for ubiquitinated-protein aggregation in neurodegenerative diseases. Here, we show that N-oleoyl-dopamine and N-arachidonyl-dopamine, which are endogenous brain substances and belong to the N-acyldopamine (AcylDA) family, generate cellular inclusions through aggresome formation without proteasome inhibition. Although AcylDA itself does not inhibit proteasome activity in vitro, it activates the rearrangement of vimentin distribution to form a vimentin cage surrounding aggresomes and sequesters ubiquitinated proteins in aggresomes. The gene transcription of p62/SQSTM1 was significantly increased by AcylDAs, whereas the transcription of other ubiquitin-dependent autophagy receptors was unaffected. Genetic depletion of p62 resulted in the loss of ubiquitinated-protein sequestration in aggresomes, indicating that p62 is a critical component of aggresomes. Furthermore, AcylDAs accelerate the aggregation of mutant huntingtin exon 1 proteins. These results suggest that aggresome formation does not require proteasome dysfunction and AcylDA-induced aggresome formation may participate in forming cytoplasmic protein inclusions.
Assuntos
Ácidos Araquidônicos/metabolismo , Dopamina/análogos & derivados , Regulação da Expressão Gênica/efeitos dos fármacos , Agregados Proteicos/efeitos dos fármacos , Proteína Sequestossoma-1/genética , Proteína Sequestossoma-1/metabolismo , Ácidos Araquidônicos/farmacologia , Autofagia/efeitos dos fármacos , Linhagem Celular , Dopamina/metabolismo , Dopamina/farmacologia , Avaliação Pré-Clínica de Medicamentos , Humanos , Proteína Huntingtina/química , Proteína Huntingtina/genética , Leupeptinas/farmacologia , Mutação , Fosforilação/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma/metabolismo , Transcrição Gênica/efeitos dos fármacosRESUMO
Huntington's disease (HD) is an autosomal dominant progressive neurological disorder characterized by motor, cognitive, and psychiatric symptoms that typically present later on in life, although juvenile cases do exist. The identification of the disease-causing mutation, a CAG triplet repeat expansion in the HTT gene, in 1993 generated numerous investigations into the cellular and molecular pathways underlying the disorder. HD mouse models have played a prominent role in these studies, and the use of these mouse models of HD in the development and evaluation of novel therapeutic strategies is reviewed in this chapter. As new interventions and therapeutic approaches are evaluated and implemented, genetic mouse models will continue to be used with the hope of developing effective treatments for HD.
Assuntos
Modelos Animais de Doenças , Terapia Genética/métodos , Doença de Huntington/terapia , Camundongos , Fármacos Neuroprotetores/uso terapêutico , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Avaliação Pré-Clínica de Medicamentos/instrumentação , Avaliação Pré-Clínica de Medicamentos/métodos , Humanos , Proteína Huntingtina/genética , Doença de Huntington/genética , Doença de Huntington/patologia , Camundongos Endogâmicos , Camundongos Transgênicos , Fármacos Neuroprotetores/farmacologia , Resultado do TratamentoRESUMO
Advances in molecular biology and genetics have been used to elucidate the fundamental genetic mechanisms underlying central nervous system (CNS) diseases, yet disease-modifying therapies are currently unavailable for most CNS conditions. Antisense oligonucleotides (ASOs) are synthetic single stranded chains of nucleic acids that bind to a specific sequence on ribonucleic acid (RNA) and regulate posttranscriptional gene expression. Decreased gene expression with ASOs might be able to reduce production of the disease-causing protein underlying dominantly inherited neurodegenerative disorders. Huntington's disease (HD), which is caused by a CAG repeat expansion in exon 1 of the huntingtin (HTT) gene and leads to the pathogenic expansion of a polyglutamine (PolyQ ) tract in the N terminus of the huntingtin protein (Htt), is a prime candidate for ASO therapy.State-of-the art translational science techniques can be applied to the development of an ASO targeting HTT RNA, allowing for a data-driven, stepwise progression through the drug development process. A deep and wide-ranging understanding of the basic, preclinical, clinical, and epidemiologic components of drug development will improve the likelihood of success. This includes characterizing the natural history of the disease, including evolution of biomarkers indexing the underlying pathology; using predictive preclinical models to assess the putative gain-of-function of mutant Htt protein and any loss-of-function of the wild-type protein; characterizing toxicokinetic and pharmacodynamic effects of ASOs in predictive animal models; developing sensitive and reliable biomarkers to monitor target engagement and effects on pathology that translate from animal models to patients with HD; establishing a drug delivery method that ensures reliable distribution to relevant CNS tissue; and designing clinical trials that move expeditiously from proof of concept to proof of efficacy. This review focuses on the translational science techniques that allow for efficient and informed development of an ASO for the treatment of HD.
Assuntos
Proteína Huntingtina/genética , Doença de Huntington/terapia , Oligonucleotídeos Antissenso/uso terapêutico , Reparo Gênico Alvo-Dirigido/métodos , Pesquisa Translacional Biomédica/métodos , Animais , Encéfalo/patologia , Modelos Animais de Doenças , Desenvolvimento de Medicamentos , Avaliação Pré-Clínica de Medicamentos/métodos , Humanos , Proteína Huntingtina/metabolismo , Doença de Huntington/genética , Doença de Huntington/patologia , Macaca fascicularis , Camundongos , Mutação , Oligonucleotídeos Antissenso/genética , Oligonucleotídeos Antissenso/farmacologia , Precursores de RNA/genética , Ratos , Resultado do TratamentoRESUMO
Huntington's disease (HD) is a neurodegenerative disorder causing cognitive and motor impairments, evolving to death within 15-20 years after symptom onset. We previously established a mouse model with the entire human HD gene containing 128 CAG repeats (YAC128) which accurately recapitulates the natural history of the human disease. Defined time points in this natural history enable the understanding of longitudinal trajectories from the neurochemical and structural points of view using non-invasive high-resolution multi-modal imaging. Accordingly, we designed a longitudinal structural imaging (MRI and DTI) and spectroscopy (1H-MRS) study in YAC128, at 3, 6, 9 and 12 months of age, at 9.4 T. Structural analysis (MRI/DTI), confirmed that the striatum is the earliest affected brain region, but other regions were also identified through connectivity analysis (pre-frontal cortex, hippocampus, globus pallidus and thalamus), suggesting a striking homology with the human disease. Importantly, we found for the first time, a negative correlation between striatal and hippocampal changes only in YAC128. In fact, the striatum showed accelerated volumetric decay in HD, as opposed to the hippocampus. Neurochemical analysis of the HD striatum suggested early neurometabolic alterations in neurotransmission and metabolism, with a significant increase in striatal GABA levels, and specifically anticorrelated levels of N-acetyl aspartate and taurine, suggesting that the later is homeostatically adjusted for neuroprotection, as neural loss, indicated by the former, is progressing. These results provide novel insights into the natural history of HD and prove a valuable role for longitudinal multi-modal panels of structural and metabolite/neurotransmission in the YAC128 model.
Assuntos
Encéfalo/metabolismo , Corpo Estriado/metabolismo , Proteína Huntingtina/genética , Doença de Huntington/genética , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Corpo Estriado/diagnóstico por imagem , Corpo Estriado/patologia , Modelos Animais de Doenças , Regulação da Expressão Gênica/genética , Humanos , Doença de Huntington/diagnóstico por imagem , Doença de Huntington/patologia , Estudos Longitudinais , Camundongos , Camundongos Transgênicos , Neostriado/diagnóstico por imagem , Neostriado/metabolismo , Neostriado/patologia , Neurônios/metabolismo , Neurônios/patologia , Tálamo/diagnóstico por imagem , Tálamo/metabolismo , Tálamo/patologia , Repetições de Trinucleotídeos/genética , Ácido gama-Aminobutírico/genética , Ácido gama-Aminobutírico/metabolismoRESUMO
Huntington's disease (HD) is a monogenic disorder, caused by mutations in the HTT gene which result in expansion of CAG triplets. The product of the mutated gene is misfolded huntingtin protein that forms aggregates leading to impairment of neuronal function, neurodegeneration, motor abnormalities and cognitive deficits. No effective cure is currently available for HD. Here we studied effects of genistein (trihydroxyisoflavone) on a HD cellular model consisting of HEK-293 cells transfected with a plasmid bearing mutated HTT gene. Both level of mutated huntingtin and number of aggregates were significantly decreased in genistein-treated HD cell model. This led to increased viability of the cells. Autophagy was up-regulated while inhibition of lysosomal functions by chloroquine impaired the genistein-mediated degradation of the mutated huntingtin aggregates. Hence, we conclude that through stimulating autophagy, genistein removes the major pathogenic factor of HD. Prolonged induction of autophagy was suspected previously to be risky for patients due to putative adverse effects; however, genistein has been demonstrated recently to be safe and suitable for long-term therapies even at doses as high as 150 mg/kg/day. Therefore, results presented in this report provide a basis for the use of genistein in further studies on development of the potential treatment of HD.
Assuntos
Autofagia/efeitos dos fármacos , Genisteína/farmacologia , Doença de Huntington/tratamento farmacológico , Autofagia/fisiologia , Cloroquina/toxicidade , Avaliação Pré-Clínica de Medicamentos , Genes Reporter , Células HEK293 , Humanos , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Doença de Huntington/patologia , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Agregação Patológica de Proteínas/tratamento farmacológico , Agregação Patológica de Proteínas/prevenção & controle , Proteínas Recombinantes de Fusão/metabolismoRESUMO
BACKGROUND: According to the Compendium of Materia Medica, Gastrodia elata (GE) Blume is a top-grade herbal medicine frequently used to treat dizziness, headaches, tetanus, and epilepsy, suggesting that it affects neurological functions. Although studies have supported its effects in preventing diverse neurodegenerations such as Huntington's disease (HD), its mechanisms require further investigation. PURPOSE: To investigate the ability of the molecular mechanism of GE to prevent mutant huntingtin (mHTT) protein aggregation by focusing on mitochondrial function and biogenesis, which have been proposed as the therapeutic targets of HD. STUDY DESIGN/METHODS: mHtt overexpression in pheochromocytoma (PC12) cells was used as an in vitro cell model of HD. A retardation assay was applied to measure protein aggregation during Htt expression. Cotransfection with transcriptional genes was used to test their relationships with HTT aggregates by monitoring with a confocal laser scanning microscope. Western blot analysis was used to estimate protein expression under different drug treatments or when cotransfected with other related genes. RESULTS: Mutant, abnormal Htt overexpression resulted in significant protein aggregation in PC12 cells. GE dose-dependently attenuated mHTT aggregates and increased cyclic-AMP response element-binding protein (CREB) phosphorylation. Adenosine A2A-R receptor (A2A-R) antagonist counteracted these phenomena. CREB overexpression significantly attenuated mHTT aggregation. GE increased the promoter activity and expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α). Furthermore, wild-type PGC-1α but not mutant PGC-1α overexpression attenuated mHTT aggregates. CONCLUSION: GE attenuated mHtt aggregation by mediating mitochondrial function and biogenesis through the A2A-R/PKA/CREB/PGC-1α-dependent pathway.