RESUMO
Amyloid-ß (Aß) plays a central role in the pathogenesis of Alzheimer's disease (AD). Because AD pathologies begin two decades before the onset of dementia, prevention of Aß amyloidosis has been proposed as a mean to block the pathological cascade. Here, we generate a transgenic plant-based vaccine, a soybean storage protein containing Aß4-10, named Aß+, for oral Aß immunization. One mg of Aß+ or control protein (Aß-) was administered to TgCRND8 mice once a week from 9 weeks up to 58 weeks. Aß+ immunization raised both anti-Aß antibodies and cellular immune responses. Spatial learning decline was prevented in the Aß+ immunized group in an extended reference memory version of Morris water maze test from 21 to 57 weeks. In Tris-buffered saline (TBS), sodium dodecyl sulfate (SDS), and formic acid (FA) serial extractions, all sets of Aß species from Aß monomer, low to high molecular weight Aß oligomers, and Aß smears had different solubility in TgCRND8 brains. Aß oligomers decreased in TBS fractions, corresponding to an increase in high molecular weight Aß oligomers in SDS extracts and Aß smears in FA fraction of the Aß+ treated group. There was significant inhibition of histological Aß burden, especially in diffuse plaques, and suppression of microglial inflammation. Processing of amyloid-ß protein precursor was not different between Aß+ and Aß- groups. No evidence of amyloid-related inflammatory angiopathy was observed. Thus, Aß+ oral immunization could be a promising, cheap, and long-term safe disease-modifying therapy to prevent the pathological process in AD.
Assuntos
Peptídeos beta-Amiloides/administração & dosagem , Disfunção Cognitiva/prevenção & controle , Imunização/métodos , Plantas Geneticamente Modificadas , Proteínas de Soja/administração & dosagem , Aprendizagem Espacial/efeitos dos fármacos , Administração Oral , Animais , Disfunção Cognitiva/genética , Disfunção Cognitiva/metabolismo , Humanos , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Endogâmicos C3H , Camundongos Transgênicos , Plantas Geneticamente Modificadas/genética , Estrutura Secundária de Proteína , Proteínas de Armazenamento de Sementes/administração & dosagem , Proteínas de Armazenamento de Sementes/genética , Proteínas de Soja/química , Proteínas de Soja/genética , Aprendizagem Espacial/fisiologiaRESUMO
Perineuritis is a rare type of peripheral neuropathy defined by swelling and cellular infiltration in the perineurium. We herein report a 52-year-old man who presented with subacute onset pain from the back to the lower limbs, muscle weakness and hypoesthesia. A sural nerve biopsy revealed perineuritis, consisting of inflammatory cell infiltration and swelling of the perineurium. Oral prednisolone, plasma exchange and intravenous immunoglobulin treatment were all effective, leading to significant improvement of the symptoms.
Assuntos
Imunoglobulinas Intravenosas/uso terapêutico , Imunoterapia/métodos , Nervos Periféricos/patologia , Doenças do Sistema Nervoso Periférico/tratamento farmacológico , Nervo Sural/patologia , Biópsia , Eletromiografia , Humanos , Fatores Imunológicos/uso terapêutico , Masculino , Pessoa de Meia-Idade , Doenças do Sistema Nervoso Periférico/diagnósticoRESUMO
Cerebrospinal fluid (CSF) amyloid-ß (Aß)42 and tau are biomarkers for Alzheimer's disease (AD); however, the effects of other neurodegenerative processes on these biomarkers remain unclear. We measured Aß40, Aß42, total tau, phosphorylated-tau, and α-synuclein in CSF and plasma using matched samples from various neurodegenerative diseases to expand our basic knowledge on these biomarkers and their practical applications. A total of 213 CSF and 183 plasma samples were analyzed from cognitively unimpaired subjects, and patients with Alzheimer's disease dementia (ADD), mild cognitive impairment (MCI), non-AD dementias, and other neurological diseases. The CSF/plasma ratios of Aß40 and Aß42 were approximately 25:1. Aß40/42 ratios in CSF and plasma were both 10:1. The CSF total tau/P181tau ratio was 6:1. The CSF/plasma α-synuclein ratio was 1:65. Significantly decreased Aß42 levels and an increased Aß40/42 ratio in CSF in ADD/MCI suggested that these relationships were specifically altered in AD. Increased total tau levels in ADD/MCI, encephalopathy, and multiple system atrophy, and increased P181tau in ADD/MCI indicated that these biomarkers corresponded to neurodegeneration and tauopathy, respectively. Although CSF α-synuclein levels were increased in ADD/MCI, there was no merit in measuring α-synuclein in CSF or plasma as a biomarker. The combination of biomarkers by the Aß40/42 ratio×p181tau reflected specific changes due to the AD pathology in ADD/MCI. Thus, CSF Aß40, Aß42, p181tau, and tau were identified as biomarkers for aggregated Aß associated state (A), aggregated tau associated state (T), and neurodegeneration state (N) pathologies in AD based on the NIA-AA criteria. Overlaps in these biomarkers need to be considered in clinical practice for differential diagnoses of neurodegenerative diseases.
Assuntos
Peptídeos beta-Amiloides/metabolismo , Doenças Neurodegenerativas/sangue , Doenças Neurodegenerativas/líquido cefalorraquidiano , Fragmentos de Peptídeos/metabolismo , alfa-Sinucleína/metabolismo , Proteínas tau/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Biomarcadores/líquido cefalorraquidiano , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doenças Neurodegenerativas/diagnóstico , Adulto JovemRESUMO
We report the case of a 53-year-old woman with severe chronic inflammatory demyelinating polyneuropathy (CIDP) who developed progressive tetraplegia with respiratory failure despite receiving a standard dose of intravenous immunoglobulin therapy (IVIg), steroid pulse therapy, plasma exchange, and cyclosporine. We administered high-dose IVIg (3 g/kg; 0.6 g/kg/day for 5 consecutive days at monthly intervals). The patient's muscle weakness gradually improved after IVIg. She recovered completely 2 years after the onset of symptoms. The effects of IVIg treatment in individuals with CIDP may vary in each patient. In patients with refractory CIDP receiving standard-dose IVIg, repeated high-dose IVIg treatment can be considered.
Assuntos
Imunoglobulinas Intravenosas/uso terapêutico , Fatores Imunológicos/uso terapêutico , Polirradiculoneuropatia Desmielinizante Inflamatória Crônica/tratamento farmacológico , Relação Dose-Resposta a Droga , Feminino , Humanos , Pessoa de Meia-Idade , Índice de Gravidade de DoençaRESUMO
OBJECTIVE: The aim of this study was to confirm determinative factors for plasma Aß and its association with cognitive function. METHODS: Fasting plasma Aß40 and Aß42 levels were measured by ELISA in 1019 participants in the Iwaki Health Promotion Project. The relationships between plasma Aß and health-related items, including physical characteristics, cognitive function tests, blood chemistry, and APOE-ε4 genotype were analyzed. RESULTS: The plasma levels of Aß40 and Aß42, and Aß40/42 ratio were found to significantly increase with aging. The age-dependent increase in Aß42 level was significantly suppressed by APOE-ε4. Renal function was an associated factor for the plasma Aß40 level. The plasma Aß42 level and Aß40/42 ratio correlated with cognitive function. INTERPRETATION: Age and APOE-ε4 are major determinative factors of plasma levels of Aß42 and the Aß40/42 ratio. These factors are critical adjustment factors for the usage of plasma Aß as a biomarker of central nervous system amyloidosis.
Assuntos
Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética , Doenças Neurodegenerativas/diagnóstico por imagem , Idoso , Atrofia , Encéfalo/patologia , Diagnóstico Diferencial , Progressão da Doença , Feminino , Humanos , Corpos de Inclusão Intranuclear/patologia , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/patologiaRESUMO
Alzheimer's disease is characterized by the presence of extracellular deposits of amyloid, primarily composed of the amyloid ß-protein (Aß). A growing body of evidence indicates that oligomeric forms of Aß play a critical role in disease causation. Soybean isoflavones are flavonoids with an isoflavone backbone. Isoflavones have been reported to protect against Aß-induced neurotoxicity in cultured cell systems, the molecular mechanisms remain unclear. Our previous studies demonstrated that red wine-related flavonoids with a flavone backbone are able to inhibit Aß assembly and destabilize preformed Aß aggregates. Here, we show that isoflavones, especially glycitein and genistein, have anti-fibrillization, anti-oligomerization and fibril-destabilizing effects on Aß(1-40) and Aß(1-42)in vitro at physiological pH and temperature, by using nucleation-dependent polymerization monitored by thioflavin T fluorescence, atomic force microscopy, electron microscopy, and photo-induced cross-linking of unmodified proteins followed by SDS-PAGE. Our three-dimensional fluorescence spectroscopic analyses demonstrated that glycitein interacted with Aß monomers, oligomers and fibrils, indicating specific binding of glycitein to these Aß species. Glycitein also interacted with different Aß fragments (Aß(1-42), Aß(1-40), Aß(1-16) and Aß(25-35)), exhibiting the highest fluorescence enhancement with Aß(25-35). We speculated that glycitein's anti-amyloidogenic properties are specifically mediated by its binding to Aß monomers, oligomers and fibrils. Isoflavones may hold promise as a treatment option for preventative strategies targeting amyloid formation in Alzheimer's disease.
Assuntos
Peptídeos beta-Amiloides/metabolismo , Isoflavonas/metabolismo , Isoflavonas/farmacologia , Fragmentos de Peptídeos/metabolismo , Peptídeos beta-Amiloides/química , Benzotiazóis , Humanos , Microscopia de Força Atômica , Microscopia Eletrônica/métodos , Fragmentos de Peptídeos/química , Glycine max/química , Espectrometria de Fluorescência/métodos , Tiazóis/químicaRESUMO
Inhibition of amyloid-ß (Aß) aggregation is an attractive therapeutic strategy for treatment of Alzheimer's disease (AD). We previously reported that vitamin A and ß-carotene inhibit fibrillation of Aß40 and Aß42 (Ono et al, 2004, Exp Neurol). In this study, we firstly examined the effects of vitamin A (retinoic acid, retinol, and retinal), ß-carotene, vitamin B2, vitamin B6, vitamin C, vitamin E, coenzyme Q10, and α-lipoic acid on oligomerization of Aß40 and Aß42 in vitro; vitamin A and ß-carotene dose-dependently inhibited oligomerization of Aß40 and Aß42. Furthermore, retinoic acid decreased cellular toxicity by inhibition of Aß42 oligomerization. Second, we analyzed how vitamin A inhibits Aß aggregation by using fluorescence spectroscopy and thioflavin T assay with two Aß fragments, Aß1-16 and Aß25-35. A fluorescence peak of retinoic acid was greatly restrained in the presence of Aß25-35, and retinoic acid inhibited aggregation of Aß25-35, but not of Aß1-16, which suggest the specific binding of retinoic acid to the C-terminal portion of Aß. Thus, vitamin A and ß-carotene might be key molecules for prevention of AD.
Assuntos
Peptídeos beta-Amiloides/antagonistas & inibidores , Peptídeos beta-Amiloides/metabolismo , Fragmentos de Peptídeos/antagonistas & inibidores , Vitamina A/farmacologia , Biopolímeros/antagonistas & inibidores , Biopolímeros/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Células HEK293 , Humanos , Fragmentos de Peptídeos/metabolismoRESUMO
The folding of amyloid ß-protein (Aß) into oligomeric, protofibrillar, and fibrillar assemblies is hypothesized to be the key pathogenic event in Alzheimer's disease (AD), with oligomeric assemblies thought to be the most neurotoxic. Inhibitors of oligomer formation, therefore, could be valuable therapeutics for patients with AD. Epidemiological studies have indicated that estrogen therapy reduces the risk of developing AD in women. Here, we examined the effects of estrogen (estrone (E1), estradiol (E2), and estriol (E3)) and related sexual steroids (androstenedione (AND) and testosterone (TES)) on the in vitro oligomer formation of Aß(1-40) and Aß(1-42) using a method of photo-induced cross-linking of unmodified proteins (PICUP) and electron microscopic studies. Estrogens (E1, E2, and E3) inhibited low-order Aß oligomer formation, and among them, E3 had the strongest in vitro activity. Estrogen could be a potential therapeutic agent to prevent or delay AD progression, and further understanding of the fact that these very similar molecules have different anti-oligomeric effects would contribute to the development of new agents.
Assuntos
Envelhecimento/metabolismo , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Hormônios Esteroides Gonadais/farmacologia , Placa Amiloide/metabolismo , Multimerização Proteica/efeitos dos fármacos , Envelhecimento/efeitos dos fármacos , Doença de Alzheimer/tratamento farmacológico , Feminino , Hormônios Esteroides Gonadais/deficiência , Hormônios Esteroides Gonadais/uso terapêutico , Humanos , Placa Amiloide/tratamento farmacológico , Pós-Menopausa/efeitos dos fármacos , Pós-Menopausa/metabolismoRESUMO
The aggregation of α-synuclein (αS) in the central nervous system (CNS) is the hallmark of multiple system atrophy (MSA) and Lewy body diseases including Parkinson's disease (PD) and dementia with Lewy bodies (DLB) (α-synucleinopathies). To test the hypothesis that patients with α-synucleinopathies have a CNS environment favorable for αS aggregation, we examined the influence of cerebrospinal fluid (CSF) from patients with MSA (n=20), DLB (n=8), and PD (n=10) on in vitro αS fibril (fαS) formation at pH 7.5 and 37°C using fluorescence spectroscopy with thioflavin S, compared with those with hereditary spinocerebellar ataxia (hSCA) (n=16), and tension-type headache (n=7). CSF from MSA patients (MSA-CSF) promoted fαS formation more strongly than PD-, hSCA-, or headache-CSF. By electron microscopic analyses, the width of fαS formed in MSA-CSF was significantly greater than others. MSA may have a CSF environment particularly favorable for fαS formation.
Assuntos
Líquido Cefalorraquidiano/química , Atrofia de Múltiplos Sistemas/líquido cefalorraquidiano , Degeneração Neural/líquido cefalorraquidiano , Neurofibrilas/metabolismo , alfa-Sinucleína/biossíntese , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Atrofia de Múltiplos Sistemas/patologia , Degeneração Neural/patologia , Neurofibrilas/patologia , Ataxias Espinocerebelares/líquido cefalorraquidiano , Ataxias Espinocerebelares/patologia , Cefaleia do Tipo Tensional/líquido cefalorraquidiano , Cefaleia do Tipo Tensional/patologia , alfa-Sinucleína/metabolismoRESUMO
The alpha-synuclein aggregation in the brain is the hallmark of Lewy body diseases, including Parkinson's disease and dementia with Lewy bodies, and multiple system atrophy. Some epidemiological studies have revealed that estrogen therapy reduces the risk of Parkinson's disease in females. We examined the effects of estriol, estradiol, estrone, androstenedione, and testosterone on the formation and destabilization of alpha-synuclein fibrils at pH 7.5 and 37 degrees C in vitro, using fluorescence spectroscopy with thioflavin S and electron microscopy. These sex hormones, especially estriol, significantly exert anti-aggregation and fibril-destabilizing effects; and hence, could be valuable preventive and therapeutic agents for alpha-synucleinopathies.
Assuntos
Hormônios Esteroides Gonadais/farmacologia , Corpos de Lewy/efeitos dos fármacos , Neurofibrilas/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , alfa-Sinucleína/efeitos dos fármacos , Benzotiazóis , Estradiol/análogos & derivados , Estradiol/metabolismo , Estradiol/farmacologia , Estriol/metabolismo , Estriol/farmacologia , Hormônios Esteroides Gonadais/química , Hormônios Esteroides Gonadais/metabolismo , Humanos , Técnicas In Vitro , Corpos de Lewy/metabolismo , Corpos de Lewy/patologia , Doença por Corpos de Lewy/tratamento farmacológico , Doença por Corpos de Lewy/metabolismo , Doença por Corpos de Lewy/fisiopatologia , Microscopia Eletrônica , Estrutura Molecular , Neurofibrilas/metabolismo , Neurofibrilas/patologia , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/metabolismo , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/metabolismo , Doença de Parkinson/fisiopatologia , Espectrometria de Fluorescência , Testosterona/análogos & derivados , Testosterona/metabolismo , Testosterona/farmacologia , Tiazóis/química , alfa-Sinucleína/metabolismoRESUMO
Lewy bodies (LBs) and Lewy neurites (LNs) in the brain constitute the main histopathological features of Parkinson's disease (PD) and dementia with Lewy bodies (DLB), and are comprised of amyloid-like fibrils composed of a small protein ( approximately 14 kDa) named alpha-synuclein (alphaS). As the aggregation of (alphaS in the brain has been implicated as a critical step in the development of the diseases, the current search for disease-modifying drugs is focused on modification of the process of (alpha S deposition in the brain. In this article, the recent developments on the molecules that inhibit the formation of alpha-synuclein fibrils (falphaS) as well as the oligomerization of alphaS are reviewed. Recently, various compounds such as curcumin, nicotine and wine-related polyphenols have been reported to inhibit the formation of falphaS, and to destabilize preformed falphaS at pH 7.5 at 37 degrees C in vitro. Although the mechanisms by which these compounds inhibit falphaS formation from falphaS, and destabilize preformed falphaS are still unclear, they could be key molecules for the development of preventives and therapeutics for PD and other alpha-synucleinopathies.
Assuntos
Antiparkinsonianos , Desenho de Fármacos , Doença de Parkinson/tratamento farmacológico , alfa-Sinucleína/metabolismo , Animais , Antiparkinsonianos/química , Antiparkinsonianos/farmacologia , Antiparkinsonianos/uso terapêutico , Encéfalo/metabolismo , Demência/tratamento farmacológico , Demência/metabolismo , Humanos , Corpos de Lewy/metabolismo , Estrutura Molecular , Doença de Parkinson/metabolismo , Relação Estrutura-AtividadeRESUMO
Amyloidosis is a clinical disorder caused by deposition of proteins that abnormally self-assemble into insoluble fibrils and impair organ function. More than 20 unrelated precursor proteins lose their native structure and misfold, leading to the formation of amyloid fibrils. The latter share cross-beta core structure in vivo and in vitro and gain abnormal functions. Local amyloid deposition occurs in the central nervous system in Alzheimer's disease (AD) and cerebral amyloid angiopathy. AD is the most common form of neurodegenerative disorder, with dementia in the elderly as well as dementia with Lewy bodies (DLB). Extracellular deposition of amyloid beta-peptide (Abeta) has been implicated as a critical step in the pathogenesis of AD. Involvement of neuroinflammation and microglial activation has been emphasized in the AD brain. Recent epidemiological studies have shown that long-term therapeutic use of non-steroidal anti-inflammatory drugs (NSAIDs) reduces the risk of developing AD and delayed the onset of AD. We review epidemiological studies of anti-AD effects of NSAIDs, experimental studies of anti-amyloidogenic as well as anti-inflammatory effects of NSAIDs, and recent clinical trials for AD with NSAIDs. We refer to the anti-fibrillogenic and fibril-destabilizing activities of NSAIDs for other proteins that can aggregate and form amyloid-like fibrils, including alpha-synuclein in DLB. The anti-amyloidogenic properties of some NSAIDs provide new insights for future therapeutic and preventative opportunities for AD and other amyloidoses, and protein-misfolding disorders.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Amiloide/metabolismo , Amiloidose/tratamento farmacológico , Anti-Inflamatórios não Esteroides/uso terapêutico , Doença de Alzheimer/epidemiologia , Doença de Alzheimer/metabolismo , Doença de Alzheimer/prevenção & controle , Amiloidose/epidemiologia , Amiloidose/metabolismo , Amiloidose/prevenção & controle , Animais , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacologia , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Ensaios Clínicos como Assunto , Humanos , Estrutura Molecular , Dobramento de Proteína , Relação Estrutura-AtividadeRESUMO
The aggregation of alpha-synuclein (alphaS) in the brain has been implicated as a critical step in the development of Lewy body diseases (LBD) [Parkinson's disease (PD)/dementia with Lewy bodies (DLB)] and multiple system atrophy (MSA). The involvement of neuroinflammation and microglial activation has been emphasized in the pathogenesis of PD. Recent epidemiological studies have revealed that therapeutic use of non-steroidal anti-inflammatory drugs (NSAIDs) reduces the risk of developing PD. Here, we examined the effects of NSAIDs, such as ibuprofen, aspirin, acetaminophen, meclofenamic acid sodium salt, sulindac sulfide, ketoprofen, flurbiprofen, diclofenac sodium salt, naproxen, and indomethacin, on the formation and destabilization of alphaS fibrils (falphaS) at pH 7.5 and 37 degrees C in vitro, using fluorescence spectroscopy with thioflavin S and electron microscopy. All examined NSAIDs, except for naproxen and indomethacin, inhibited the formation of falphaS in a dose-dependent manner. Moreover, these molecules dose-dependently destabilized preformed falphaS. The overall activity was in the order: ibuprofen approximately aspirin approximately acetaminophen approximately meclofenamic acid sodium salt approximately sulindac sulfide>ketoprofen approximately flurbiprofen approximately diclofenac sodium salt>naproxen approximately indomethacin. These findings indicate that NSAIDs could be key molecules for the development of therapeutic or preventive agents for LBD and MSA.
Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Emaranhados Neurofibrilares/efeitos dos fármacos , Emaranhados Neurofibrilares/metabolismo , alfa-Sinucleína/metabolismo , Animais , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/classificação , Relação Dose-Resposta a Droga , Técnicas In Vitro , Microscopia Eletrônica de Varredura/métodos , Emaranhados Neurofibrilares/ultraestrutura , Espectrometria de Fluorescência , Fatores de TempoRESUMO
Inhibition of the assembly of amyloid beta-peptide (Abeta) as well as the destabilization of preformed beta-amyloid fibrils (fAbeta) in the central nervous system could be valuable therapeutics of patients with Alzheimer's disease (AD). Epidemiological studies have indicated that estrogen therapy reduced the risk of developing AD in women. Here, we examined the effects of estrogen (estrone (E1), estradiol (E2), and estriol (E3)) and related sexual steroids (androstenedione (AND) and testosterone (TES)) on the polymerization, extension and destabilization of fAbeta(1-42) and fAbeta(1-40) at pH 7.5 at 37 degrees C in vitro, using fluorescence spectroscopic analysis with thioflavin T and electron microscopic studies. E1, E2, and E3 dose-dependently inhibited the formation, as well as destabilization of fAbetas. The overall anti-amyloidogenic activity of these molecules was in the order of: E3>E2=E1>>AND=TES. Estrogen could be a potential therapeutic agent to prevent or delay AD progression.
Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Estrogênios/farmacologia , Peptídeos beta-Amiloides/ultraestrutura , Estrogênios/química , Microscopia Eletrônica , Estrutura Molecular , Fragmentos de Peptídeos/metabolismoRESUMO
The aggregation of alpha-synuclein (alphaS) has been implicated as a critical step in the development of Lewy body diseases (LBD) and multiple system atrophy (MSA). Both retrospective and prospective epidemiological studies have consistently demonstrated an inverse association between cigarette smoking and Parkinson's disease (PD). We used fluorescence spectroscopy with thioflavin S, electron microscopy and atomic force microscopy to examine the effects of nicotine, pyridine, and N-methylpyrrolidine on the formation of alphaS fibrils (f alphaS) from wild-type alphaS (alphaS (WT)) and A53T mutant alphaS (A53T) and on preformed f alpha Ss. Nicotine dose-dependently inhibited the f alphaS formation from both alphaS (WT) and A53T. Moreover, nicotine dose-dependently destabilized preformed f alpha Ss. These effects of nicotine were similar to those of N-methylpyrrolidine. The anti-fibrillogenic activity of nicotine may be exerted not only by the inhibition of f alphaS formation but also by the destabilization of preformed f alphaS. Additionally, this effect may be attributed to N-methylpyrrolidine moieties of nicotine.
Assuntos
Doença por Corpos de Lewy/prevenção & controle , Microfibrilas/efeitos dos fármacos , Microfibrilas/patologia , Nicotina/farmacologia , Nicotina/uso terapêutico , Agonistas Nicotínicos/farmacologia , Agonistas Nicotínicos/uso terapêutico , Benzotiazóis , Humanos , Cinética , Doença por Corpos de Lewy/patologia , Microfibrilas/ultraestrutura , Microscopia de Força Atômica , Microscopia Eletrônica , Mutação , Piridinas/metabolismo , Pirrolidinas/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Espectrometria de Fluorescência , Tiazóis , alfa-Sinucleína/genética , alfa-Sinucleína/metabolismoRESUMO
The aggregation of alpha-synuclein (alphaS) in the brain has been implicated as a critical step in the development of Lewy body diseases (LBD) and multiple system atrophy (MSA). Among the antioxidant strategies proposed, increasing evidence points to the possibility of achieving neuroprotection by dopamine agonists, as well as monoamine oxidase B inhibitors. We showed previously that the anti-Parkinsonian agents dose-dependently inhibited beta-amyloid fibrils (fAbeta)(1-40) and fAbeta(1-42) formation as well as destabilized preformed fAbetas. Using fluorescence spectroscopy with thioflavin S, electron microscopy, and atomic force microscopy, we examined the effects of anti-Parkinsonian agents, selegiline, dopamine, pergolide, bromocriptine, and trihexyphenidyl on the formation of alphaS fibrils (falphaS) and on preformed falphaS. All molecules except for trihexyphenidyl, dose-dependently inhibited the formation of falphaS. Moreover, these molecules dose-dependently destabilized preformed falphaS. The overall activity of the molecules examined was in the order of: selegiline = dopamine > pergolide > bromocriptine. These agents and other compounds related structurally could be key molecules for the development of therapeutics for LBD and MSA.
Assuntos
Antiparkinsonianos/farmacologia , Emaranhados Neurofibrilares/química , Polímeros/química , alfa-Sinucleína/química , Antiparkinsonianos/química , Bromocriptina/química , Bromocriptina/farmacologia , Dopamina/química , Dopamina/farmacologia , Relação Dose-Resposta a Droga , Técnicas In Vitro , Estrutura Molecular , Emaranhados Neurofibrilares/efeitos dos fármacos , Pergolida/química , Pergolida/farmacologia , Selegilina/química , Selegilina/farmacologia , Triexifenidil/química , Triexifenidil/farmacologia , alfa-Sinucleína/efeitos dos fármacosRESUMO
How various anti-amyloidogenic compounds inhibit the formation of Alzheimer's beta-amyloid fibrils (fAbeta) from amyloid beta-peptide (Abeta) and destabilize fAbeta remains poorly understood. Using spectrophotometry, spectrofluorometry, atomic force microscopy, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and surface plasmon resonance (SPR), we investigated the anti-amyloidogenic effects of five flavonoids on fAbeta in vitro. Oxidized flavonoids generally inhibited fAbeta(1-40) formation significantly more potently than fresh compounds. Characterization of the novel fluorescence of myricetin (Myr) emitted at 575 nm with an excitation maximum at 430 nm in the presence of fAbeta(1-40) revealed the specific binding of Myr to fAbeta(1-40). By SPR analysis, distinct association and dissociation reactions of Myr with fAbeta(1-40) were observed, in contrast to the very weak binding to the Abeta monomer. A significant decrease in the rate of fibril extension was observed when >0.5 microM Myr was injected into the SPR experimental system. These findings suggest that flavonoids, especially Myr, exert an anti-amyloidogenic effect in vitro by preferentially and reversibly binding to the amyloid fibril structure of fAbeta, rather than to Abeta monomers.
Assuntos
Doença de Alzheimer/metabolismo , Amiloide/antagonistas & inibidores , Amiloide/química , Flavonoides/química , Peptídeos beta-Amiloides/antagonistas & inibidores , Peptídeos beta-Amiloides/química , Eletroforese em Gel de Poliacrilamida , Microscopia de Força Atômica , Fragmentos de Peptídeos/antagonistas & inibidores , Fragmentos de Peptídeos/química , Ligação Proteica , Espectrometria de Fluorescência , Espectrofotometria/métodos , Ressonância de Plasmônio de SuperfícieRESUMO
Inhibition of the formation of beta-amyloid fibrils (fAbeta), as well as the destabilization of preformed fAbeta in the CNS would be attractive therapeutic targets for the treatment of Alzheimer's disease (AD). Using fluorescence spectroscopic analysis with thioflavin T and electron microscopic studies, we examined the effects of alpha-lipoic acid (LA) and the metabolic product of LA, dihydrolipoic acid (DHLA), on the formation, extension, and destabilization of fAbeta at pH 7.5 at 37 degrees C in vitro. LA and DHLA dose-dependently inhibited fAbeta formation from amyloid beta-protein, as well as their extension. Moreover, they destabilized preformed fAbetas. LA and DHLA could be key molecules for the development of therapeutics for AD.
Assuntos
Peptídeos beta-Amiloides/efeitos dos fármacos , Peptídeos beta-Amiloides/ultraestrutura , Amiloide/antagonistas & inibidores , Ácido Tióctico/farmacologia , Peptídeos beta-Amiloides/química , Benzotiazóis , Masoprocol/farmacologia , Microscopia Eletrônica , Rifampina/farmacologia , Espectrometria de Fluorescência , Tetraciclina/farmacologia , Tiazóis/farmacologia , Ácido Tióctico/análogos & derivadosRESUMO
Inhibition of the formation of beta-amyloid fibrils (fAbeta), as well as the destabilization of preformed fAbeta in the CNS, would be attractive therapeutic targets for the treatment of Alzheimer's disease (AD). We reported previously that curcumin (Cur) inhibits fAbeta formation from Abeta and destabilizes preformed fAbeta in vitro. Using fluorescence spectroscopic analysis with thioflavin T and electron microscopic studies, we examined the effects of ferulic acid (FA) on the formation, extension, and destabilization of fAbeta at pH 7.5 at 37 degrees C in vitro. We next compared the anti-amyloidogenic activities of FA with Cur, rifampicin, and tetracycline. Ferulic acid dose-dependently inhibited fAbeta formation from amyloid beta-peptide, as well as their extension. Moreover, it destabilized preformed fAbetas. The overall activity of the molecules examined was in the order of: Cur > FA > rifampicin = tetracycline. FA could be a key molecule for the development of therapeutics for AD.