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1.
Lancet Neurol ; 19(10): 872-878, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32949547

RESUMO

Studies in experimental animals show transmissibility of amyloidogenic proteins associated with prion diseases, Alzheimer's disease, Parkinson's disease, and other neurodegenerative diseases. Although these data raise potential concerns for public health, convincing evidence for human iatrogenic transmission only exists for prions and amyloid ß after systemic injections of contaminated growth hormone extracts or dura mater grafts derived from cadavers. Even though these procedures are now obsolete, some reports raise the possibility of iatrogenic transmission of amyloid ß through putatively contaminated neurosurgical equipment. Iatrogenic transmission of amyloid ß might lead to amyloid deposition in the brain parenchyma and blood vessel walls, potentially resulting in cerebral amyloid angiopathy after several decades. Cerebral amyloid angiopathy can cause life-threatening brain haemorrhages; yet, there is no proof that the transmission of amyloid ß can also lead to Alzheimer's dementia. Large, long-term epidemiological studies and sensitive, cost-efficient tools to detect amyloid are needed to better understand any potential routes of amyloid ß transmission and to clarify whether other similar proteopathic seeds, such as tau or α-synuclein, can also be transferred iatrogenically.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Doenças Neurodegenerativas/metabolismo , Vigilância da População , Doença de Alzheimer/etiologia , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/toxicidade , Animais , Síndrome de Creutzfeldt-Jakob/metabolismo , Síndrome de Creutzfeldt-Jakob/patologia , Síndrome de Creutzfeldt-Jakob/transmissão , Humanos , Doenças Neurodegenerativas/etiologia , Doenças Neurodegenerativas/patologia , Doença de Parkinson/etiologia , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Fatores de Risco
2.
Nat Commun ; 11(1): 4790, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32963242

RESUMO

Preventing aggregation of amyloid beta (Aß) peptides is a promising strategy for the treatment of Alzheimer's disease (AD), and gold nanoparticles have previously been explored as a potential anti-Aß therapeutics. Here we design and prepare 3.3 nm L- and D-glutathione stabilized gold nanoparticles (denoted as L3.3 and D3.3, respectively). Both chiral nanoparticles are able to inhibit aggregation of Aß42 and cross the blood-brain barrier (BBB) following intravenous administration without noticeable toxicity. D3.3 possesses a larger binding affinity to Aß42 and higher brain biodistribution compared with its enantiomer L3.3, giving rise to stronger inhibition of Aß42 fibrillation and better rescue of behavioral impairments in AD model mice. This conjugation of a small nanoparticle with chiral recognition moiety provides a potential therapeutic approach for AD.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/efeitos dos fármacos , Ouro/farmacologia , Transtornos da Memória/tratamento farmacológico , Nanopartículas Metálicas/química , Fragmentos de Peptídeos/efeitos dos fármacos , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Masculino , Transtornos da Memória/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Simulação de Acoplamento Molecular , Fragmentos de Peptídeos/metabolismo , Estereoisomerismo
3.
Nat Commun ; 11(1): 4571, 2020 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-32917871

RESUMO

Early therapeutic interventions are essential to prevent Alzheimer Disease (AD). The association of several inflammation-related genetic markers with AD and the early activation of pro-inflammatory pathways in AD suggest inflammation as a plausible therapeutic target. Inflammatory Caspase-1 has a significant impact on AD-like pathophysiology and Caspase-1 inhibitor, VX-765, reverses cognitive deficits in AD mouse models. Here, a one-month pre-symptomatic treatment of Swedish/Indiana mutant amyloid precursor protein (APPSw/Ind) J20 and wild-type mice with VX-765 delays both APPSw/Ind- and age-induced episodic and spatial memory deficits. VX-765 delays inflammation without considerably affecting soluble and aggregated amyloid beta peptide (Aß) levels. Episodic memory scores correlate negatively with microglial activation. These results suggest that Caspase-1-mediated inflammation occurs early in the disease and raise hope that VX-765, a previously Food and Drug Administration-approved drug for human CNS clinical trials, may be a useful drug to prevent the onset of cognitive deficits and brain inflammation in AD.


Assuntos
Envelhecimento/metabolismo , Doença de Alzheimer/metabolismo , Disfunção Cognitiva/metabolismo , Serpinas/metabolismo , Proteínas Virais/metabolismo , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/metabolismo , Animais , Comportamento Animal , Disfunção Cognitiva/tratamento farmacológico , Citocinas/metabolismo , Dipeptídeos/sangue , Dipeptídeos/farmacologia , Modelos Animais de Doenças , Encefalite/metabolismo , Encefalite/patologia , Feminino , Humanos , Inflamação/metabolismo , Masculino , Transtornos da Memória/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Serpinas/sangue , Serpinas/farmacologia , Memória Espacial/fisiologia , Proteínas Virais/sangue , Proteínas Virais/farmacologia , para-Aminobenzoatos/sangue , para-Aminobenzoatos/farmacologia
4.
PLoS One ; 15(8): e0236283, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764794

RESUMO

Geographic atrophy (GA) is an advanced form of dry age-related macular degeneration (AMD), in which local inflammation and hyperactivity of the complement pathway have been implicated in its pathophysiology. This study explores whether any surrogate biomarkers are specifically associated with GA. Plasma from subjects with GA, intermediate dry AMD and non-AMD control were evaluated in 2 cohorts. Cohort 1 was assayed in a 320-analyte Luminex library. Statistical analysis was performed using non-parametric and parametric methods (Kruskal-Wallis, principal component analysis, partial least squares and multivariate analysis of variance (MANOVA) and univariate ANCOVAs). Bioinformatic analysis was conducted and identified connections to the amyloid pathway. Statistically significant biomarkers identified in Cohort 1 were then re-evaluated in Cohort 2 using individual ELISA and multiplexing. Of 320 analytes in Cohort 1, 273 were rendered measurable, of which 56 were identified as changing. Among these markers, 40 were identified in univariate ANCOVAs. Serum amyloid precursor protein (sAPP) was analyzed by a separate ELISA and included in further analyses. The 40 biomarkers, sAPP and amyloid-ß (Aß) (1-42) (included for comparison) were evaluated in Cohort 2. This resulted in 11 statistically significant biomarkers, including sAPP and Aß(1-40), but not Aß(1-42). Other biomarkers identified included serum proteases- tissue plasminogen activator, tumor-associated trypsinogen inhibitor, matrix metalloproteinases 7 and 9, and non-proteases- insulin-like growth factor binding protein 6, AXL receptor tyrosine kinase, omentin, pentraxin-3 and osteopontin. Findings suggest that there is a preferential processing of APP to Aß(1-40) over Aß(1-42), and a potential role for the carboxylase activity of the γ-secretase protein, which preferentially splices sAPPß to Aß(1-40). Other markers are associated with the breakdown and remodeling of the extracellular matrix, and loss of homeostasis, possibly within the photoreceptor-retinal pigment epithelium-choriocapillaris complex. These data suggest novel disease pathways associated with GA pathogenesis and could provide potential novel targets for treatment of GA.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Atrofia Geográfica/sangue , Degeneração Macular/complicações , Epitélio Pigmentado da Retina/patologia , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Biomarcadores/metabolismo , Estudos de Coortes , Biologia Computacional , Feminino , Fundo de Olho , Atrofia Geográfica/diagnóstico , Atrofia Geográfica/etiologia , Atrofia Geográfica/patologia , Humanos , Degeneração Macular/sangue , Degeneração Macular/patologia , Masculino , Pessoa de Meia-Idade , Imagem Óptica , Transdução de Sinais , Ativador de Plasminogênio Tecidual
5.
Nat Commun ; 11(1): 3942, 2020 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-32770063

RESUMO

Though discovered over 100 years ago, the molecular foundation of sporadic Alzheimer's disease (AD) remains elusive. To better characterize the complex nature of AD, we constructed multiscale causal networks on a large human AD multi-omics dataset, integrating clinical features of AD, DNA variation, and gene- and protein-expression. These probabilistic causal models enabled detection, prioritization and replication of high-confidence master regulators of AD-associated networks, including the top predicted regulator, VGF. Overexpression of neuropeptide precursor VGF in 5xFAD mice partially rescued beta-amyloid-mediated memory impairment and neuropathology. Molecular validation of network predictions downstream of VGF was also achieved in this AD model, with significant enrichment for homologous genes identified as differentially expressed in 5xFAD brains overexpressing VGF. Our findings support a causal role for VGF in protecting against AD pathogenesis and progression.


Assuntos
Doença de Alzheimer/etiologia , Encéfalo/patologia , Fatores de Crescimento Neural/metabolismo , Mapas de Interação de Proteínas , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Animais , Conjuntos de Dados como Assunto , Modelos Animais de Doenças , Feminino , Perfilação da Expressão Gênica , Redes Reguladoras de Genes , Estudo de Associação Genômica Ampla , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Fatores de Crescimento Neural/genética , Mapeamento de Interação de Proteínas , Proteômica
6.
PLoS One ; 15(8): e0237153, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32791516

RESUMO

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease characterized by cognitive dysfunction and memory loss as the main symptoms. The deposition of amyloid beta (Aß) and tau hyperphosphorylation are hallmarks of AD and are major therapeutic targets. However, the exact etiology has not yet been fully elucidated; thus, no drug that cures the disease has been approved. JBPOS0101 is a phenyl carbamate compound that has been tested as a drug for epileptic diseases. In our previous study, we showed that JBPOS0101 attenuated the accumulation of Aß as well as the deficits in learning and memory in the 5xFAD mouse model. Here, we tested the dose effect (70 or 35 mg/kg) of JBPOS0101 on the memory defect and pathological markers and further investigated the underlying mechanisms in 5xFAD mice. In the behavior tests, JBPOS0101 treatment ameliorated deficits in learning and memory. Moreover, JBPOS0101 attenuated Aß accumulation and tau phosphorylation. The elevated phosphorylation levels of the active GSK3ß form (GSK3ß-y216) in 5xFAD, which are responsible for tau phosphorylation, decreased in the JBPOS0101-treated groups. Furthermore, the elevation of reactive astrocytes and microglia in 5xFAD mice was attenuated in JBPOS0101-treated groups. These data suggest that JBPOS0101 may be a new drug candidate to lessen amyloid- and tau-related pathology by regulating glial cells.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/metabolismo , Microglia/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Proteínas tau/metabolismo , Animais , Feminino , Glicogênio Sintase Quinase 3 beta/metabolismo , Memória , Camundongos , Microglia/metabolismo , Fármacos Neuroprotetores/uso terapêutico
7.
Chem Biol Interact ; 328: 109144, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32653415

RESUMO

The debilitating nature of cognitive impairment in epilepsy and the potential of some traditional antiepileptics to further deteriorate cognitive function are areas of growing concern. Glucagon-like peptide-1 (GLP-1) deficiency has been linked to reduced seizure threshold as well as cognitive dysfunction. Here, we tested whether sitagliptin (SITA), by virtue of its neuroprotective properties, could alleviate both epilepsy and associated cognitive dysfunction in a rat model of kindling epilepsy. Chemical kindling was induced by subconvulsive doses of pentylenetetrazol (PTZ) (30 mg/kg; i.p). SITA (50 mg/kg; p.o) was administered 1 h before PTZ injections. SITA conceivably attenuated PTZ hippocampal histological insult, preserved neuronal integrity and amended neurotransmitter perturbations in rat hippocampi paralleled with enhanced hippocampal GLP-1 levels as well as the downstream cAMP content and protein kinase A (PKA) activity. Moreover, SITA improved cognitive functioning of rats in the Morris water maze which was coupled with hampered hippocampal p(Ser404)-tau and ß-amyloid proteins. SITA replenished p(Ser9)-glycogen synthase kinase-3ß (GSK-3ß). It also opposed the boosted matrix metalloproteinase-9 (MMP-9), brain-derived neurotrophic factor (BDNF), and insulin-like growth factor-1 (IGF-1) levels associated with PTZ administration along with mitigation of both ß-secretase-1 (BACE1) immunoreactivity and receptor for advanced glycation end products (RAGE) protein level in rat hippocampi. In conclusion, SITA subdues epileptic and cognitive upshots of PTZ kindling in rats, which might correspond to the modulation of BACE1, amyloidogenic/RAGE axis as well as GSK-3ß/MMP-9/BDNF signaling cascade. SITA effects are probably mediated via boosting GLP-1 and subsequently enhancing GLP-1/GLP-1R signaling.


Assuntos
Secretases da Proteína Precursora do Amiloide/metabolismo , Amiloide/metabolismo , Ácido Aspártico Endopeptidases/metabolismo , Transtornos Cognitivos/induzido quimicamente , Transtornos Cognitivos/metabolismo , Excitação Neurológica/efeitos dos fármacos , Receptor para Produtos Finais de Glicação Avançada/metabolismo , Transdução de Sinais , Fosfato de Sitagliptina/farmacologia , Peptídeos beta-Amiloides/metabolismo , Animais , Biomarcadores/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Transtornos Cognitivos/patologia , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Glicogênio Sintase Quinase 3 beta/metabolismo , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Fator de Crescimento Insulin-Like I/metabolismo , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Inibição Neural/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Neurotransmissores/metabolismo , Pentilenotetrazol , Ratos Wistar , Convulsões/induzido quimicamente , Convulsões/metabolismo , Convulsões/patologia , Transdução de Sinais/efeitos dos fármacos , Memória Espacial/efeitos dos fármacos , Proteínas tau/metabolismo
8.
Life Sci ; 257: 118020, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32603820

RESUMO

Alzheimer's disease (AD) is the most common form of dementia worldwide. ß-amyloid peptide (Aß) is currently assumed to be the main cause of synaptic dysfunction and cognitive impairments in AD, but the molecular signaling pathways underlying its neurotoxic consequences have not yet been completely explored. Additional investigations regarding these pathways will contribute to development of new therapeutic targets. In context, developing evidence suggest that Aß decreases brain-derived neurotrophic factor (BDNF) mostly by lowering phosphorylated cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) protein. In fact, it has been observed that brain or serum levels of BDNF appear to be beneficial markers for cognitive condition. In addition, the participation of transcription mediated by CREB has been widely analyzed in the memory process and AD development. Designing pharmacologic or genetic therapeutic approaches based on the targeting of CREB-BDNF signaling could be a promising treatment potential for AD. In this review, we summarize data demonstrating the role of CREB-BDNF signaling pathway in cognitive status and mediation of Aß toxicity in AD. Finally, we also focus on the developing intervention methods for improvement of cognitive decline in AD based on targeting of CREB-BDNF pathway.


Assuntos
Doença de Alzheimer/terapia , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Encéfalo/metabolismo , Fator Neurotrófico Derivado do Encéfalo/fisiologia , Cognição/fisiologia , Transtornos Cognitivos/metabolismo , Disfunção Cognitiva/metabolismo , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/fisiologia , Modelos Animais de Doenças , Humanos , Memória/fisiologia , Neurônios/metabolismo , Fosforilação , Transdução de Sinais
9.
Life Sci ; 257: 118037, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32622942

RESUMO

Palmitoylethanolamide (PEA) is an endogenous lipid mediator that, also by blunting astrocyte activation, demonstrated beneficial properties in several in vitro and in vivo models of Alzheimer's disease (AD). In the present study, we used astrocyte-neuron co-cultures from 3xTg-AD mouse (i.e. an animal model of AD) cerebral cortex to further investigate on the role of astrocytes in PEA-induced neuroprotection. To this aim, we evaluated the number of viable cells, apoptotic nuclei, microtubule-associated protein-2 (MAP2) positive cells and morphological parameters in cortical neurons co-cultured with cortical astrocytes pre-exposed, or not, to Aß42 (0.5 µM; 24 h) or PEA (0.1 µM; 24 h). Pre-exposure of astrocytes to Aß42 failed to affect the viability, the number of neuronal apoptotic nuclei, MAP2 positive cell number, neuritic aggregations/100 µm, dendritic branches per neuron, the neuron body area, the length of the longest dendrite and number of neurites/neuron in 3xTg-AD mouse astrocyte-neuron co-cultures. Compared to neurons from wild-type (non-Tg) mouse co-cultures, 3xTg-AD mouse neurons co-cultured with astrocytes from this mutant mice displayed higher number of apoptotic nuclei, lower MAP2 immunoreactivity and several morphological changes. These signs of neuronal suffering were significantly counteracted when the 3xTg-AD mouse cortical neurons were co-cultured with 3xTg-AD mouse astrocytes pre-exposed to PEA. The present data suggest that in astrocyte-neuron co-cultures from 3xTg-AD mice, astrocytes contribute to neuronal damage and PEA, by possibly counteracting reactive astrogliosis, improved neuronal survival. These findings further support the role of PEA as a possible new therapeutic opportunity in AD treatment.


Assuntos
Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Etanolaminas/farmacologia , Ácidos Palmíticos/farmacologia , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Sobrevivência Celular/efeitos dos fármacos , Córtex Cerebral/metabolismo , Técnicas de Cocultura , Modelos Animais de Doenças , Etanolaminas/metabolismo , Gliose , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Proteínas Associadas aos Microtúbulos , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Ácidos Palmíticos/metabolismo , Proteínas tau/metabolismo
10.
Ecotoxicol Environ Saf ; 203: 110975, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32678756

RESUMO

Manganese (Mn) produces cholinergic neuronal loss in basal forebrain (BF) region that was related to cognitive dysfunction induced after single and repeated Mn treatment. All processes that generate cholinergic neuronal loss in BF remain to be understood. Mn exposure may produce the reduction of BF cholinergic neurons by increasing amyloid beta (Aß) and phosphorylated Tau (pTau) protein levels, altering heat shock proteins' (HSPs) expression, disrupting proteasome P20S activity and generating oxidative stress. These mechanisms, described to be altered by Mn in regions different than BF, could lead to the memory and learning process alteration produced after Mn exposure. The research performed shows that single and repeated Mn treatment of SN56 cholinergic neurons from BF induces P20S inhibition, increases Aß and pTau protein levels, produces HSP90 and HSP70 proteins expression alteration, and oxidative stress generation, being the last two effects mediated by NRF2 pathway alteration. The increment of Aß and pTau protein levels was mediated by HSPs and proteasome dysfunction. All these mechanisms mediated the cell decline observed after Mn treatment. Our results are relevant because they may assist to reveal the processes leading to the neurotoxicity and cognitive alterations observed after Mn exposure.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Prosencéfalo Basal/efeitos dos fármacos , Neurônios Colinérgicos/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Proteínas de Choque Térmico HSP70/metabolismo , Proteínas de Choque Térmico HSP90/metabolismo , Manganês/toxicidade , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteínas tau/metabolismo , Animais , Prosencéfalo Basal/metabolismo , Prosencéfalo Basal/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Neurônios Colinérgicos/metabolismo , Neurônios Colinérgicos/patologia , Relação Dose-Resposta a Droga , Poluentes Ambientais/metabolismo , Manganês/metabolismo , Camundongos , Estresse Oxidativo/efeitos dos fármacos
11.
PLoS One ; 15(7): e0235543, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645028

RESUMO

Senile plaques frequently contain Aß-pE(3), a N-terminally truncated Aß species that is more closely linked to AD compared to other Aß species. Tau protein is highly phosphorylated at several residues in AD, and specifically phosphorylation at Ser202/Thr205 is known to be increased in AD. Several studies suggest that formation of plaques and tau phosphorylation might be linked to each other. To evaluate if Aß-pE(3) and ptau Ser202/Thr205 levels correlate in human and transgenic AD mouse models, we analyzed human cortical and hippocampal brain tissue of different Braak stages as well as murine brain tissue of two transgenic mouse models for levels of Aß-pE(3) and ptau Ser202/Thr205 and correlated the data. Our results show that Aß-pE(3) formation is increased at early Braak stages while ptau Ser202/Thr205 mostly increases at later stages. Further analyses revealed strongest correlations between the two pathologies in the temporal, frontal, cingulate, and occipital cortex, however correlation in the hippocampus was weaker. Evaluation of murine transgenic brain tissue demonstrated a slow but steady increase of Aß-pE(3) from 6 to 12 months of age in the cortex and hippocampus of APPSL mice, and a very early and strong Aß-pE(3) increase in 5xFAD mice. ptau Ser202/Thr205 levels increased at the age of 9 months in APPSL mice and at 6 months in 5xFAD mice. Our results show that Aß-pE(3) and ptau Ser202/Thr205 levels strongly correlate in human as well as murine tissues, suggesting that tau phosphorylation might be amplified by Aß-pE(3).


Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Encéfalo/metabolismo , Proteínas tau/metabolismo , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/genética , Animais , Encéfalo/patologia , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Fosforilação , Ácido Pirrolidonocarboxílico/química , Especificidade da Espécie , Proteínas tau/genética
12.
Proc Natl Acad Sci U S A ; 117(25): 14482-14492, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32518112

RESUMO

Cerebral amyloid angiopathy (CAA), where beta-amyloid (Aß) deposits around cerebral blood vessels, is a major contributor of vascular dysfunction in Alzheimer's disease (AD) patients. However, the molecular mechanism underlying CAA formation and CAA-induced cerebrovascular pathology is unclear. Hereditary cerebral amyloid angiopathy (HCAA) is a rare familial form of CAA in which mutations within the (Aß) peptide cause an increase in vascular deposits. Since the interaction between Aß and fibrinogen increases CAA and plays an important role in cerebrovascular damage in AD, we investigated the role of the Aß-fibrinogen interaction in HCAA pathology. Our work revealed the most common forms of HCAA-linked mutations, Dutch (E22Q) and Iowa (D23N), resulted in up to a 50-fold stronger binding affinity of Aß for fibrinogen. In addition, the stronger interaction between fibrinogen and mutant Aßs led to a dramatic perturbation of clot structure and delayed fibrinolysis. Immunofluorescence analysis of the occipital cortex showed an increase of fibrin(ogen)/Aß codeposition, as well as fibrin deposits in HCAA patients, compared to early-onset AD patients and nondemented individuals. Our results suggest the HCAA-type Dutch and Iowa mutations increase the interaction between fibrinogen and Aß, which might be central to cerebrovascular pathologies observed in HCAA.


Assuntos
Peptídeos beta-Amiloides/genética , Encéfalo/patologia , Angiopatia Amiloide Cerebral Familiar/patologia , Fibrina/metabolismo , Fibrinogênio/metabolismo , Fragmentos de Peptídeos/genética , Peptídeos beta-Amiloides/metabolismo , Angiopatia Amiloide Cerebral Familiar/genética , Feminino , Fibrinogênio/isolamento & purificação , Fibrinólise/genética , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Fragmentos de Peptídeos/metabolismo , Ligação Proteica/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo
13.
J Pharmacol Sci ; 143(4): 245-254, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32482409

RESUMO

The accumulation of insoluble amyloid ß (Aß) peptides is one of the pathological changes in Alzheimer's disease (AD), which induced synaptic plasticity impairment and excitatory amino acid toxicity associated with decreased memory function. Xingnaojing (XNJ), a well-known prescription in traditional Chinese medicine, has been used for the treatment of stroke for many years in China. In this study, we aim to investigate the therapeutic effects of XNJ in a hippocampus of Aß1-42 induced mouse model of AD which showed significant memory loss and impaired synaptic morphology and function. Treatment of XNJ could attenuate spatial and working memory dysfunction, increase dendritic spine density and improve long-term potential (LTP) induction. In addition, XNJ treatment significantly increased the level of N-methyl-d-aspartate receptors (NMDARs) and inhibit the NMDA/α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) ratio in AD mice. XNJ treatment also activated the AKT/mechanistic target of rapamycin (mTOR) pathway, while inhibition of the mTOR pathway by rapamycin could reverse the protective effects of XNJ treatment. In conclusion, XNJ protected against synaptic plasticity and memory impairment in AD mice via the activation of AKT/mTOR signaling pathway, suggesting XNJ as an alternative treatment for AD.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/fisiopatologia , Peptídeos beta-Amiloides/metabolismo , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/uso terapêutico , Transtornos da Memória/tratamento farmacológico , Plasticidade Neuronal/efeitos dos fármacos , Fragmentos de Peptídeos/metabolismo , Doença de Alzheimer/metabolismo , Animais , Modelos Animais de Doenças , Masculino , Camundongos Endogâmicos C57BL
14.
Lancet ; 395(10242): 1988-1997, 2020 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-32593336

RESUMO

BACKGROUND: Alzheimer's disease and its complications are the leading cause of death in adults with Down syndrome. Studies have assessed Alzheimer's disease in individuals with Down syndrome, but the natural history of biomarker changes in Down syndrome has not been established. We characterised the order and timing of changes in biomarkers of Alzheimer's disease in a population of adults with Down syndrome. METHODS: We did a dual-centre cross-sectional study of adults with Down syndrome recruited through a population-based health plan in Barcelona (Spain) and through services for people with intellectual disabilities in Cambridge (UK). Cognitive impairment in participants with Down syndrome was classified with the Cambridge Cognitive Examination for Older Adults with Down Syndrome (CAMCOG-DS). Only participants with mild or moderate disability were included who had at least one of the following Alzheimer's disease measures: apolipoprotein E allele carrier status; plasma concentrations of amyloid ß peptides 1-42 and 1-40 and their ratio (Aß1-42/1-40), total tau protein, and neurofilament light chain (NFL); tau phosphorylated at threonine 181 (p-tau), and NFL in cerebrospinal fluid (CSF); and one or more of PET with 18F-fluorodeoxyglucose, PET with amyloid tracers, and MRI. Cognitively healthy euploid controls aged up to 75 years who had no biomarker abnormalities were recruited from the Sant Pau Initiative on Neurodegeneration. We used a first-order locally estimated scatterplot smoothing curve to determine the order and age at onset of the biomarker changes, and the lowest ages at the divergence with 95% CIs are also reported where appropriate. FINDINGS: Between Feb 1, 2013, and June 28, 2019 (Barcelona), and between June 1, 2009, and Dec 31, 2014 (Cambridge), we included 388 participants with Down syndrome (257 [66%] asymptomatic, 48 [12%] with prodromal Alzheimer's disease, and 83 [21%] with Alzheimer's disease dementia) and 242 euploid controls. CSF Aß1-42/1-40 and plasma NFL values changed in individuals with Down syndrome as early as the third decade of life, and amyloid PET uptake changed in the fourth decade. 18F-fluorodeoxyglucose PET and CSF p-tau changes occurred later in the fourth decade of life, followed by hippocampal atrophy and changes in cognition in the fifth decade of life. Prodromal Alzheimer's disease was diagnosed at a median age of 50·2 years (IQR 47·5-54·1), and Alzheimer's disease dementia at 53·7 years (49·5-57·2). Symptomatic Alzheimer's disease prevalence increased with age in individuals with Down syndrome, reaching 90-100% in the seventh decade of life. INTERPRETATION: Alzheimer's disease in individuals with Down syndrome has a long preclinical phase in which biomarkers follow a predictable order of changes over more than two decades. The similarities with sporadic and autosomal dominant Alzheimer's disease and the prevalence of Down syndrome make this population a suitable target for Alzheimer's disease preventive treatments. FUNDING: Instituto de Salud Carlos III, Fundació Bancaria La Caixa, Fundació La Marató de TV3, Medical Research Council, and National Institutes of Health.


Assuntos
Doença de Alzheimer/metabolismo , Biomarcadores/sangue , Síndrome de Down/complicações , Adulto , Doença de Alzheimer/líquido cefalorraquidiano , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/epidemiologia , Peptídeos beta-Amiloides/metabolismo , Amiloidose/diagnóstico por imagem , Amiloidose/patologia , Apolipoproteínas E/metabolismo , Estudos de Casos e Controles , Disfunção Cognitiva/psicologia , Estudos Transversais , Síndrome de Down/epidemiologia , Síndrome de Down/mortalidade , Síndrome de Down/psicologia , Fluordesoxiglucose F18/administração & dosagem , Humanos , Imagem por Ressonância Magnética/métodos , Pessoa de Meia-Idade , Proteínas de Neurofilamentos/líquido cefalorraquidiano , Tomografia por Emissão de Pósitrons/métodos , Prevalência , Espanha/epidemiologia , Reino Unido/epidemiologia , Proteínas tau/metabolismo
15.
Nat Commun ; 11(1): 3014, 2020 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-32541820

RESUMO

Formation of amyloid-beta (Aß) oligomer pores in the membrane of neurons has been proposed to explain neurotoxicity in Alzheimer's disease (AD). Here, we present the three-dimensional structure of an Aß oligomer formed in a membrane mimicking environment, namely an Aß(1-42) tetramer, which comprises a six stranded ß-sheet core. The two faces of the ß-sheet core are hydrophobic and surrounded by the membrane-mimicking environment while the edges are hydrophilic and solvent-exposed. By increasing the concentration of Aß(1-42) in the sample, Aß(1-42) octamers are also formed, made by two Aß(1-42) tetramers facing each other forming a ß-sandwich structure. Notably, Aß(1-42) tetramers and octamers inserted into lipid bilayers as well-defined pores. To establish oligomer structure-membrane activity relationships, molecular dynamics simulations were carried out. These studies revealed a mechanism of membrane disruption in which water permeation occurred through lipid-stabilized pores mediated by the hydrophilic residues located on the core ß-sheets edges of the oligomers.


Assuntos
Peptídeos beta-Amiloides/química , Membrana Celular/química , Bicamadas Lipídicas/química , Simulação de Dinâmica Molecular , Fragmentos de Peptídeos/química , Conformação Proteica , Multimerização Proteica , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Membrana Celular/metabolismo , Condutividade Elétrica , Humanos , Interações Hidrofóbicas e Hidrofílicas , Bicamadas Lipídicas/metabolismo , Síndromes Neurotóxicas/metabolismo , Fragmentos de Peptídeos/metabolismo , Água/metabolismo
16.
Gene ; 754: 144854, 2020 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-32525045

RESUMO

Alzheimer's disease (AD) is one of the most common forms of neurodegenerative diseases. Aggregation of Aß42 and hyperphosphorylated tau are two major hallmarks of AD. Whether different forms of tau (soluble or hyperphosphorylated) or Aß are the main culprit in the events observed in AD is still under investigation. Here, we examined the effect of wild-type, prone to hyperphosphorylation and hyperphosphorylated tau, and also Aß42 peptide on the brain antioxidant defense system and two mitochondrial genes, Marf (homologous to human MFN2) and Drp1 involved in mitochondrial dynamics in transgenic Drosophila melanogaster. AD is an age associated disease. Therefore, the activity of antioxidant agents, CAT, SOD, and GSH levels and the mRNA levels of Marf and Drp1 were assessed in different time points of the flies lifespan. Reduction in cognitive function and antioxidant activity was observed in all transgenic flies at any time point. The most and the least effect on the eye phenotype was exerted by hyperphosphorylated tau and Aß42, respectively. In addition, the most remarkable alteration in Marf and Drp1 mRNA levels was observed in transgenic flies expressing hyperphosphorylated tau when pan neuronal expression of transgenes was applied. However, when the disease causing gene expression was confined to the mushroom body, Marf and Drp1 mRNA levels alteration was more prominent in tauWT and tauE14 transgenic flies, respectively. In conclusion, in spite of antioxidant deficiency caused by different types of tau and Aß42, it seems that tau exerts more toxic effect on the eye phenotype and mitochondrial genes regulation (Marf and Drp1). Moreover, different mechanisms seem to be involved in mitochondrial genes dysregulation when Aß or various forms of tau are expressed.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Animais Geneticamente Modificados/metabolismo , Drosophila melanogaster/metabolismo , Dinaminas/metabolismo , GTP Fosfo-Hidrolases/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , RNA Mensageiro/metabolismo , Proteínas tau/metabolismo , Animais , Animais Geneticamente Modificados/genética , Encéfalo/metabolismo , Drosophila melanogaster/genética , Dinaminas/genética , GTP Fosfo-Hidrolases/genética , Regulação da Expressão Gênica , Transtornos da Memória/metabolismo , Transtornos da Memória/patologia , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/genética , Fosforilação , RNA Mensageiro/genética , Proteínas tau/genética
17.
Nat Med ; 26(6): 952-963, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32514169

RESUMO

In Alzheimer's disease, amyloid deposits along the brain vasculature lead to a condition known as cerebral amyloid angiopathy (CAA), which impairs blood-brain barrier (BBB) function and accelerates cognitive degeneration. Apolipoprotein (APOE4) is the strongest risk factor for CAA, yet the mechanisms underlying this genetic susceptibility are unknown. Here we developed an induced pluripotent stem cell-based three-dimensional model that recapitulates anatomical and physiological properties of the human BBB in vitro. Similarly to CAA, our in vitro BBB displayed significantly more amyloid accumulation in APOE4 compared to APOE3. Combinatorial experiments revealed that dysregulation of calcineurin-nuclear factor of activated T cells (NFAT) signaling and APOE in pericyte-like mural cells induces APOE4-associated CAA pathology. In the human brain, APOE and NFAT are selectively dysregulated in pericytes of APOE4 carriers, and inhibition of calcineurin-NFAT signaling reduces APOE4-associated CAA pathology in vitro and in vivo. Our study reveals the role of pericytes in APOE4-mediated CAA and highlights calcineurin-NFAT signaling as a therapeutic target in CAA and Alzheimer's disease.


Assuntos
Apolipoproteína E4/genética , Barreira Hematoencefálica/metabolismo , Calcineurina/metabolismo , Angiopatia Amiloide Cerebral/genética , Fatores de Transcrição NFATC/genética , Pericitos/metabolismo , Peptídeos beta-Amiloides/metabolismo , Apolipoproteína E3/genética , Apolipoproteína E3/metabolismo , Apolipoproteína E4/metabolismo , Barreira Hematoencefálica/citologia , Humanos , Técnicas In Vitro , Células-Tronco Pluripotentes Induzidas , Fatores de Transcrição NFATC/metabolismo , Permeabilidade , RNA-Seq , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
18.
Proc Natl Acad Sci U S A ; 117(24): 13509-13518, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32493749

RESUMO

Protein misfolding and aggregation is the hallmark of numerous human disorders, including Alzheimer's disease. This process involves the formation of transient and heterogeneous soluble oligomers, some of which are highly cytotoxic. A major challenge for the development of effective diagnostic and therapeutic tools is thus the detection and quantification of these elusive oligomers. Here, to address this problem, we develop a two-step rational design method for the discovery of oligomer-specific antibodies. The first step consists of an "antigen scanning" phase in which an initial panel of antibodies is designed to bind different epitopes covering the entire sequence of a target protein. This procedure enables the determination through in vitro assays of the regions exposed in the oligomers but not in the fibrillar deposits. The second step involves an "epitope mining" phase, in which a second panel of antibodies is designed to specifically target the regions identified during the scanning step. We illustrate this method in the case of the amyloid ß (Aß) peptide, whose oligomers are associated with Alzheimer's disease. Our results show that this approach enables the accurate detection and quantification of Aß oligomers in vitro, and in Caenorhabditis elegans and mouse hippocampal tissues.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Anticorpos/imunologia , Agregados Proteicos , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/química , Animais , Anticorpos/química , Anticorpos/metabolismo , Especificidade de Anticorpos , Caenorhabditis elegans , Modelos Animais de Doenças , Epitopos , Hipocampo/metabolismo , Camundongos , Ligação Proteica , Conformação Proteica , Anticorpos de Domínio Único
19.
Am J Chin Med ; 48(4): 945-966, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32476431

RESUMO

Tetramethylpyrazine has shown neuroprotective and axonal outgrowth-promoting effects and can improve cognitive deficit in a rat model of chronic hypoperfusion. However, the role of tetramethylpyrazine in sevoflurane-induced neurotoxicity is still vague. Therefore, this study was designed to investigate the effects and mechanisms of tetramethylpyrazine on sevoflurane-induced autophagy, apoptosis, and the expression of BACE1 and A[Formula: see text] in SH-SY5Y cells. We measured the expression levels of the apoptosis protein markers Bax and Bcl-2, autophagy protein markers Atg5 and LC3-II, BACE1, and A[Formula: see text] in SH-SY5Y cells after sevoflurane treatment and determined the effects of tetramethylpyrazine on sevoflurane-induced expression of these proteins after silencing GPR50 or Atg5 with siRNA in vitro. We found that exposure to 3.4% sevoflurane for 6 h decreased the expression of autophagy protein markers and increased the expression of the apoptosis protein markers, BACE1, and A[Formula: see text] in SH-SY5Y cells. The number of red puncta (autolysosomes) and yellow puncta (autophagosomes) in each SH-SY5Y cell decreased after transient transfection with the mRFP-GFP-LC3 expression plasmid. Silencing of GPR50 decreased the expression of pCREB, Atg5, and LC3-II, while silencing of Atg5 increased the expression of BACE1 and A[Formula: see text] in SH-SY5Y cells. Our results demonstrate that tetramethylpyrazine attenuated sevoflurane-induced neurotoxicity by enhancing autophagy through the GPR50/CREB pathway in SH-SY5Y cells.


Assuntos
Autofagia/efeitos dos fármacos , Autofagia/genética , Proteína de Ligação a CREB/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neuroprostanos , Pirazinas/farmacologia , Pirazinas/uso terapêutico , Receptores Acoplados a Proteínas-G/metabolismo , Sevoflurano/toxicidade , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Secretases da Proteína Precursora do Amiloide/genética , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/genética , Peptídeos beta-Amiloides/metabolismo , Apoptose/efeitos dos fármacos , Apoptose/genética , Ácido Aspártico Endopeptidases/genética , Ácido Aspártico Endopeptidases/metabolismo , Proteína 5 Relacionada à Autofagia/genética , Proteína 5 Relacionada à Autofagia/metabolismo , Expressão Gênica/efeitos dos fármacos , Humanos , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Células Tumorais Cultivadas
20.
Gene ; 755: 144904, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32540373

RESUMO

BACKGROUND: Aquaporins (AQPs) are water channel proteins robustly presenting in the central nervous system (CNS). Increasing evidence suggests the crucial role of AQP1 in the pathogenesis of CNS injury but scarce data are provided for the potential role of AQP1 in Alzheimer's disease (AD). Thus, the present study aimed to investigate the effects of AQP1 on cognitive function in a mouse model of AD. METHODS: A mouse model of AD was established by using the ß-amyloid isoform Aß1-42, and then assessed by the step-through test and water maze experiment. The expression of AQP1 was quantified in the AD model. The effects of AQP1 on the cognitive function of AD mice and the Wnt signaling pathway were elucidated using gain- and loss-of-function approaches. Furthermore, hippocampal neurons were isolated and treated with Aß1-42 for in vitro experiments and the effects of the Wnt signaling pathway on hippocampal neuron apoptosis were analyzed with the use of inhibitor or activator of this pathway. RESULTS: AQP1 was highly-expressed in the AD mouse model while AQP1 silencing improved cognitive function in AD mice. Besides, silencing of AQP1 exhibited protective effects on hippocampal neurons in AD mice. Furthermore, AQP1 inhibited the Wnt signaling pathway while AQP1 promoted neuronal apoptosis by inhibiting the Wnt signaling pathway, thereby damaging the cognitive function. CONCLUSIONS: AQP1 silencing attenuates the cognitive impairment in AD through activation of the Wnt signaling pathway, highlighting a novel therapeutic target against AD.


Assuntos
Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Aquaporina 1/metabolismo , Via de Sinalização Wnt , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Animais , Apoptose/fisiologia , Aquaporina 1/genética , Encéfalo/metabolismo , Cognição/fisiologia , Modelos Animais de Doenças , Hipocampo/metabolismo , Masculino , Aprendizagem em Labirinto , Camundongos , Camundongos Transgênicos , Neurônios/metabolismo
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