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1.
Brain Nerve ; 71(10): 1039-1051, 2019 Oct.
Artigo em Japonês | MEDLINE | ID: mdl-31588048

RESUMO

Dementia is a leading cause of death in many countries. Late-onset Alzheimer's disease (LOAD) is the most common form of dementia, with approximately 35 million affected people. LOAD shows a high heritability (h2) of 58-79%. Clarifying the genetic architecture of LOAD could contribute to precision medicine. In recent years, large-scale genome-wide association studies (GWASs) and their meta-analyses with a large sample size have elucidated the disease-susceptible genes and disease-causing pathways. To date, meta-analyses of GWASs in the Caucasian population have successfully identified approximately 40 LOAD risk loci. The gene set and disease pathway analysis obtained from the results of GWASs suggested biological mechanisms involving brain immune function, lipid-related processes, tau binding proteins, and degradation of amyloid precursor proteins in the pathogenesis of LOAD. Furthermore, the exome sequencing analysis in Japanese individuals with LOAD also revealed a rare variant with a large effect of SHARPIN in LOAD susceptibility, and the variant protein possibly affects the immune response through aberrant cellular localization, which may result in attenuated NF-κB activity in the brain. These findings could provide biological and pharmaceutical approaches in precision medicine for LOAD.


Assuntos
Doença de Alzheimer/genética , Patrimônio Genético , Estudo de Associação Genômica Ampla , Predisposição Genética para Doença , Humanos , NF-kappa B/metabolismo , Ubiquitinas/genética , Proteínas tau/metabolismo
2.
Nat Cell Biol ; 21(9): 1086-1092, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31481789

RESUMO

Tau is an intrinsically disordered protein, which diffuses on microtubules1. In neurodegenerative diseases, collectively termed tauopathies, malfunction of tau and its detachment from axonal microtubules are correlated with axonal degeneration2. Tau can protect microtubules from microtubule-degrading enzymes such as katanin3. However, how tau carries out this regulatory function is still unclear. Here, using in vitro reconstitution, we show that tau molecules on microtubules cooperatively form cohesive islands that are kinetically distinct from tau molecules that individually diffuse on microtubules. Dependent on the tau concentration in solution, the islands reversibly grow or shrink by addition or release of tau molecules at their boundaries. Shielding microtubules from kinesin-1 motors and katanin, the islands exhibit regulatory qualities distinct from a comparably dense layer of diffusible tau. Superprocessive kinesin-8 motors penetrate the islands and cause their disassembly. Our results reveal a microtubule-dependent phase of tau that constitutes an adaptable protective layer on the microtubule surface. We anticipate that other intrinsically disordered axonal proteins display a similar cooperative behaviour and potentially compete with tau in regulating access to the microtubule surface.


Assuntos
Cinesina/metabolismo , Microtúbulos/metabolismo , Neurônios/metabolismo , Proteínas tau/metabolismo , Adenosina Trifosfatases/metabolismo , Animais , Axônios/metabolismo , Células Cultivadas , Katanina/metabolismo , Cinética , Doenças Neurodegenerativas/metabolismo
3.
Nat Cell Biol ; 21(9): 1078-1085, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31481790

RESUMO

Tau is an abundant microtubule-associated protein in neurons. Tau aggregation into insoluble fibrils is a hallmark of Alzheimer's disease and other types of dementia1, yet the physiological state of tau molecules within cells remains unclear. Using single-molecule imaging, we directly observe that the microtubule lattice regulates reversible tau self-association, leading to localized, dynamic condensation of tau molecules on the microtubule surface. Tau condensates form selectively permissible barriers, spatially regulating the activity of microtubule-severing enzymes and the movement of molecular motors through their boundaries. We propose that reversible self-association of tau molecules, gated by the microtubule lattice, is an important mechanism of the biological functions of tau, and that oligomerization of tau is a common property shared between the physiological and disease-associated forms of the molecule.


Assuntos
Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Espastina/metabolismo , Proteínas tau/metabolismo , Animais , Camundongos , Neuroimagem/métodos , Neurônios/metabolismo , Suínos
4.
BMC Neurol ; 19(1): 211, 2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-31464590

RESUMO

BACKGROUND: THK5351 and flortaucipir tau ligands have high affinity for paired helical filament tau, yet diverse off-target bindings have been reported. Recent data support the hypothesis that THK5351 binds to monoamine oxidase B (MAO-B) expressed from reactive astrocytes and that flortaucipir has an affinity toward MAO-A and B; however, pathological evidence is lacking. We performed a head-to-head comparison of the two tau ligands in a sporadic Creutzfeldt-Jakob disease (CJD) patient and performed an imaging-pathological correlation study. CASE PRESENTATION: A 67-year-old man visited our clinic a history of 6 months of rapidly progressive dementia, visual disturbance, and akinetic mutism. Diffusion-weighted imaging showed cortical diffusion restrictions in the left temporo-parieto-occipital regions. 18F-THK5351 PET, but not 18F-flortaucipir PET showed high uptake in the left temporo-parieto-occipital regions, largely overlapping with the diffusion restricted areas. Cerebrospinal fluid analysis was weakly positive for 14-3-3 protein and pathogenic prion protein was found. The patient showed rapid cognitive decline along with myoclonic seizures and died 13 months after his first visit. A post-mortem study revealed immunoreactivity for PrPsc, no evidence of neurofibrillary tangles, and abundant astrocytosis which was reactive for MAO-B antibody. CONCLUSIONS: Our findings add pathological evidence that increased THK5351 uptake in sporadic CJD patients might be caused by an off-target binding driven by its high affinity for MAO-B.


Assuntos
Aminopiridinas/farmacologia , Carbolinas/farmacologia , Síndrome de Creutzfeldt-Jakob/diagnóstico por imagem , Síndrome de Creutzfeldt-Jakob/patologia , Tomografia por Emissão de Pósitrons/métodos , Quinolinas/farmacologia , Idoso , Autopsia , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Humanos , Masculino , Monoaminoxidase/metabolismo , Emaranhados Neurofibrilares/patologia , Proteínas tau/metabolismo
5.
Clin Biochem ; 73: 26-31, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31400306

RESUMO

Neuropathological diagnostic criteria of neurodegenerative disorders are based on the presence of specific inclusions in a specific area of brain tissue that correlate with clinical manifestations. Concomitant neurodegenerative disorders correspond to a combination of two (or more) different fully developed diseases in the same patient. Concomitant neurodegenerative pathology represents the presence of definite neurodegeneration and deposits of pathological proteins specific for another disease, which is not, however, fully developed. Very frequent overlaps include Alzheimer's disease and alpha-synuclein inclusions. Nevertheless, careful neuropathological investigations reveal an increasing frequency of different co-pathologies in examined brains. In Alzheimer's disease, protein TDP-43 may co-aggregate, but it is not clear whether this is atypical isolated Alzheimer's disease or overlap of Alzheimer's disease with early frontotemporal lobar degeneration. Comorbidities of Alzheimer's disease and tauopathies are relatively rare. A combination of vascular pathology with primary neurodegeneration (mostly Alzheimer's disease or dementia with Lewy bodies) is historically called mixed dementia. Overlap of different neuropathologically confirmed neurodegenerations could lead to atypical and unusual clinical presentations and may be responsible for faster disease progression. Several CSF biomarkers have been evaluated for their utility in diagnostic processes in different neurodegenerative dementias; however, evidence regarding their role in neurodegenerative overlaps is still limited.


Assuntos
Doença de Alzheimer/metabolismo , Proteínas de Ligação a DNA/metabolismo , Doença por Corpos de Lewy/metabolismo , Agregação Patológica de Proteínas/metabolismo , alfa-Sinucleína/metabolismo , Proteínas tau/metabolismo , Doença de Alzheimer/patologia , Biomarcadores/metabolismo , Humanos , Doença por Corpos de Lewy/patologia , Agregação Patológica de Proteínas/patologia
6.
Orv Hetil ; 160(33): 1289-1295, 2019 Aug.
Artigo em Húngaro | MEDLINE | ID: mdl-31401858

RESUMO

The ever-growing average age of the society significantly increases the occurrence of Alzheimer's disease. The increased prevalence represents considerable social and economic burden, which urges the development of diagnostic and therapeutic methods in the field. The most common cause of dementia is Alzheimer's disease, the typical histopathological abnormality of which are well known. The detection of functional changes results in the early diagnosis of the disease, which precedes the morphological changes by years. Positron-emission tomography plays an important role in the demonstration of metabolic changes. The glucose metabolic pattern differs significantly in each clinical form of dementia. The most important ß-amyloid-binding radiopharmaceuticals that should be highlighted are [11C]Pittsburgh compound B that is widely used in the research and [18F]florbetapir that is commonly approved in diagnostics. Tracers visualising neurofibrillary tangles consisting of tau protein appeared most recently. The development continues; newer and newer radiopharmaceuticals appear. These tracers play an important role in both the research and the diagnostics. Orv Hetil. 2019; 160(33): 1289-1295.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Peptídeos beta-Amiloides/metabolismo , Encéfalo/diagnóstico por imagem , Imagem Molecular , Emaranhados Neurofibrilares/metabolismo , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos , Proteínas tau/metabolismo , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Encéfalo/metabolismo , Encéfalo/patologia , Progressão da Doença , Humanos , Emaranhados Neurofibrilares/patologia , Placa Amiloide/diagnóstico por imagem , Placa Amiloide/metabolismo , Placa Amiloide/patologia
7.
Nervenarzt ; 90(9): 891-897, 2019 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-31332452

RESUMO

Alzheimer's disease is histopathologically characterized by aggregation of two proteins, namely amyloid-beta peptide and tau protein. Whereas former intervention trials focused particularly on the amyloid pathology, recent therapeutic approaches are directed against the tau pathology. This article summarizes recent progress in anti-tau therapies, especially therapies based on anti-tau immunization and antisense oligonucleotides (ASO).


Assuntos
Doença de Alzheimer , Proteínas tau , Doença de Alzheimer/terapia , Peptídeos beta-Amiloides/metabolismo , Humanos , Imunoterapia , Oligonucleotídeos Antissenso/uso terapêutico , Proteínas tau/antagonistas & inibidores , Proteínas tau/metabolismo
8.
Nat Commun ; 10(1): 2909, 2019 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-31266957

RESUMO

Cells form and use biomolecular condensates to execute biochemical reactions. The molecular properties of non-membrane-bound condensates are directly connected to the amino acid content of disordered protein regions. Lysine plays an important role in cellular function, but little is known about its role in biomolecular condensation. Here we show that protein disorder is abundant in protein/RNA granules and lysine is enriched in disordered regions of proteins in P-bodies compared to the entire human disordered proteome. Lysine-rich polypeptides phase separate into lysine/RNA-coacervates that are more dynamic and differ at the molecular level from arginine/RNA-coacervates. Consistent with the ability of lysine to drive phase separation, lysine-rich variants of the Alzheimer's disease-linked protein tau undergo coacervation with RNA in vitro and bind to stress granules in cells. Acetylation of lysine reverses liquid-liquid phase separation and reduces colocalization of tau with stress granules. Our study establishes lysine as an important regulator of cellular condensation.


Assuntos
Lisina/metabolismo , RNA/química , RNA/metabolismo , Proteínas tau/química , Proteínas tau/metabolismo , Acetilação , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Linhagem Celular , Grânulos Citoplasmáticos/genética , Grânulos Citoplasmáticos/metabolismo , Humanos , Lisina/química , Lisina/genética , RNA/genética , Proteínas tau/genética
9.
Nat Commun ; 10(1): 3090, 2019 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-31300647

RESUMO

The role of brain somatic mutations in Alzheimer's disease (AD) is not well understood. Here, we perform deep whole-exome sequencing (average read depth 584×) in 111 postmortem hippocampal formation and matched blood samples from 52 patients with AD and 11 individuals not affected by AD. The number of somatic single nucleotide variations (SNVs) in AD brain specimens increases significantly with aging, and the rate of mutation accumulation in the brain is 4.8-fold slower than that in AD blood. The putatively pathogenic brain somatic mutations identified in 26.9% (14 of 52) of AD individuals are enriched in PI3K-AKT, MAPK, and AMPK pathway genes known to contribute to hyperphosphorylation of tau. We show that a pathogenic brain somatic mutation in PIN1 leads to a loss-of-function mutation. In vitro mimicking of haploinsufficiency of PIN1 aberrantly increases tau phosphorylation and aggregation. This study provides new insights into the genetic architecture underlying the pathogenesis of AD.


Assuntos
Doença de Alzheimer/genética , Peptidilprolil Isomerase de Interação com NIMA/genética , Agregação Patológica de Proteínas/genética , Proteínas tau/metabolismo , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/genética , Doença de Alzheimer/patologia , Animais , Linhagem Celular Tumoral , Feminino , Técnicas de Silenciamento de Genes , Haploinsuficiência , Hipocampo/citologia , Hipocampo/patologia , Humanos , Mutação com Perda de Função , Masculino , Camundongos , Pessoa de Meia-Idade , Taxa de Mutação , Peptidilprolil Isomerase de Interação com NIMA/metabolismo , Neurônios , Fosforilação/genética , Polimorfismo de Nucleotídeo Único , Agregação Patológica de Proteínas/patologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sequenciamento Completo do Exoma
10.
J Agric Food Chem ; 67(30): 8348-8360, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31304751

RESUMO

We have recently demonstrated that tau hyperphosphorylation causes diabetic synaptic neurodegeneration of retinal ganglion cells (RGCs), which might be the earliest affair during the pathogenesis of diabetic retinopathy (DR). Thus, there is a pressing need to seek therapeutic agents possessing neuroprotective effects against tau hyperphosphorylation in RGCs for arresting the progression of DR. Here, using a well-characterized diabetes model of db/db mouse, we discovered that topical ocular application of 10 mg/kg/day of ginsenoside Rg1 (GRg1), one of the major active ingredients extracted from Panax ginseng and Panax notoginseng, ameliorated hyperphosphorylated tau-triggered RGCs synaptic neurodegeneration in diabetic mice. The neuroprotective effects of GRg1 on diabetic retinae were abrogated when retinal IRS-1 or Akt was suppressed by intravitreal injection with si-IRS-1 or topically coadministered with a specific inhibitor of Akt, respectively. However, selective repression of retinal GSK3ß by intravitreal administration of si-GSK3ß rescued the neuroprotective properties of GRg1 when Akt was inactivated. Therefore, the present study showed for the first time that GRg1 can prevent hyperphosphorylated tau-induced synaptic neurodegeneration of RGCs via activation of IRS-1/Akt/GSK3ß signaling in the early phase of DR. Moreover, our data clarify the potential therapeutic significance of GRg1 for neuroprotective intervention strategies of DR.


Assuntos
Retinopatia Diabética/tratamento farmacológico , Ginsenosídeos/administração & dosagem , Glicogênio Sintase Quinase 3 beta/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , Fármacos Neuroprotetores/administração & dosagem , Proteínas Proto-Oncogênicas c-akt/metabolismo , Células Ganglionares da Retina/efeitos dos fármacos , Proteínas tau/metabolismo , Animais , Retinopatia Diabética/genética , Retinopatia Diabética/metabolismo , Glicogênio Sintase Quinase 3 beta/genética , Humanos , Proteínas Substratos do Receptor de Insulina/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Degeneração Neural/tratamento farmacológico , Degeneração Neural/genética , Degeneração Neural/metabolismo , Panax notoginseng/química , Fosforilação , Extratos Vegetais/administração & dosagem , Proteínas Proto-Oncogênicas c-akt/genética , Retina/patologia , Células Ganglionares da Retina/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas tau/genética
11.
Yakugaku Zasshi ; 139(7): 1021-1025, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31257249

RESUMO

Abnormal proteins such as tau or α-synuclein that accumulate in brains with dementia have been shown to propagate like prion proteins. However, the expression patterns of tau in the mouse brain are different from those in humans, and the pathogenesis in the animal model of abnormal tau propagation remains incompletely understood. To overcome this problem, a novel mouse showing tau expression patterns similar to those of humans was developed using genome editing techniques. We inoculated the brain of this mouse with a sarkosyl-insoluble fraction containing abnormal tau derived from tauopathy patients and examined the accumulation of tau pathologies. We also performed a detailed analysis of the relationship between the inoculation site and the sites where tau accumulates abnormally by histochemical and neuronal circuitry and elucidated the propagation mechanism of the abnormally accumulated protein. This research is expected to lead to the development of novel drugs for the treatment of dementia using the innovative approach of "inhibition of abnormal protein propagation".


Assuntos
Encéfalo/metabolismo , Proteínas tau/metabolismo , Animais , Demência/tratamento farmacológico , Demência/metabolismo , Modelos Animais de Doenças , Descoberta de Drogas , Edição de Genes , Humanos , Camundongos , Proteínas Priônicas , Agregação Patológica de Proteínas , Tauopatias
12.
J Toxicol Sci ; 44(7): 493-503, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31270305

RESUMO

Methamphetamine (METH) is a potent and highly addictive central nervous system stimulant. The association between METH exposure and Alzheimer's disease (AD) has gained more attention, but, the mechanisms behind METH-induced neuron-related adverse outcomes remain poorly understood. With the western blot assay, our results revealed that METH exposure significantly increased the expression of AD-associated pathological proteins, including the amyloid precursor protein (APP) and the phosphorylated tau protein (p-tau). Meanwhile, the insulin signaling was disturbed after the administration of METH, since the key insulin signaling proteins, such as p-AKT, p-GSK3α, p-GSK3ß and p-ERK, were reduced. Additionally, the linking between the pathological proteins and the insulin signaling mediated by METH in the present work was verified by the treatment with the insulin signaling enhancer rosiglitazone, which was shown to improve the insulin signaling and decrease APP and p-tau expression. Thus, targeting insulin signaling may provide novel insights into potential therapeutic intervention for METH-mediated AD-like neurodegeneration.


Assuntos
Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Estimulantes do Sistema Nervoso Central/efeitos adversos , Expressão Gênica , Insulina/fisiologia , Metanfetamina/efeitos adversos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Proteínas tau/genética , Proteínas tau/metabolismo , Doença de Alzheimer/induzido quimicamente , Doença de Alzheimer/genética , Linhagem Celular Tumoral , MAP Quinases Reguladas por Sinal Extracelular/genética , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Quinase 3 da Glicogênio Sintase/genética , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta/metabolismo , Humanos , Fosforilação , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/fisiologia
13.
J Agric Food Chem ; 67(27): 7684-7693, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31203623

RESUMO

This study investigated the alleviative effect of caffeic acid (CA) on Alzheimer's disease (AD) pathogenesis and associated mechanisms in high-fat (HF) diet-induced hyperinsulinemic rats. The results of a Morris water maze indicated that, by administrating CA (30 mg/kg b.w./day) for 30 weeks, the memory and learning impairments in HF-induced hyperinsulinemic rats were significantly ameliorated. CA also enhanced superoxide dismutase and glutathione free radical scavenger activity in hyperinsulinemic rats. The Western blot data further confirmed that protein expressions of phosphorylated-glycogen synthase kinase 3ß (GSK3ß) were significantly increased, whereas the expression of phosphorylated-tau protein decreased in the hippocampus of rats administered with CA in comparison with the HF group. Moreover, the expression of amyloid precursor protein (APP) and ß-site APP cleaving enzyme were attenuated, subsequently lowering the level of ß-amyloid 1-42 (Aß 1-42) in the hippocampus of CA-treated hyperinsulinemic rats. CA also significantly increased the expression of synaptic proteins in HF rats.


Assuntos
Doença de Alzheimer/prevenção & controle , Peptídeos beta-Amiloides/metabolismo , Encéfalo/metabolismo , Ácidos Cafeicos/administração & dosagem , Insulina/metabolismo , Plasticidade Neuronal/efeitos dos fármacos , Doença de Alzheimer/metabolismo , Animais , Antioxidantes/química , Córtex Cerebral/química , Córtex Cerebral/enzimologia , Córtex Cerebral/metabolismo , Dieta Hiperlipídica , Modelos Animais de Doenças , Glutationa/metabolismo , Glicogênio Sintase Quinase 3 beta/análise , Glicogênio Sintase Quinase 3 beta/metabolismo , Hipocampo/química , Hipocampo/enzimologia , Hipocampo/metabolismo , Hiperinsulinismo/etiologia , Hiperinsulinismo/metabolismo , Masculino , Fosforilação , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Proteínas tau/análise , Proteínas tau/metabolismo
14.
Nat Neurosci ; 22(8): 1217-1222, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31235932

RESUMO

Variants in the triggering receptor expressed on myeloid cells 2 (TREM2) have been associated with increased risk for sporadic, late-onset Alzheimer's disease. Here we show that germline knockout of Trem2 or the TREM2R47H variant reduces microgliosis around amyloid-ß plaques and facilitates the seeding and spreading of neuritic plaque tau aggregates. These findings demonstrate a key role for TREM2 and microglia in limiting the development of peri-plaque tau pathologies.


Assuntos
Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Placa Amiloide/genética , Placa Amiloide/metabolismo , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Tauopatias/genética , Tauopatias/metabolismo , Proteínas tau/genética , Proteínas tau/metabolismo , Animais , Córtex Cerebral/patologia , Camundongos , Camundongos Knockout , Microglia/patologia
15.
Eur J Med Chem ; 177: 291-301, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31158745

RESUMO

Based on our previous research on the fluorinated phenylquinoxaline scaffold, in this study, different positions of N,N-dimethyl amino group, and alkyl linkers with various lengths were introduced into this scaffold to regulate their lipophilicity and binding affinity to Tau. Four novel 99mTc/Re complexes with diethyl iminodiacetate chelator were synthesized and evaluated as Tau imaging tracers in the brain of Alzheimer's disease. Their specific binding to neurofibrillary tangles was verified by in vitro fluorescence staining and further confirmed by the results of immunofluorescence staining on the same brain sections from AD patient and Tg-tau mice. From in vitro binding assay using recombinant Tau aggregates, complex 4.2 with 6-N(CH3)2 and longer carbon chain (n = 4) displayed the highest affinity (Kd = 59.95 nM). [99mTc]4.2 was achieved by the ligand exchange reaction between dicarboxylic precursor and [99mTc(CO)3(H2O)3]+ intermediate with radiochemical yield over 45%. Ex vivo biodistribution studies on normal ICR mice revealed that [99mTc]4.2 exhibited moderate initial brain uptake (0.61% ID/g) and more structure optimizations are still required to improve the blood-brain barrier permeability.


Assuntos
Doença de Alzheimer/diagnóstico , Complexos de Coordenação/química , Corantes Fluorescentes/química , Compostos de Organotecnécio/química , Quinoxalinas/química , Proteínas tau/metabolismo , Idoso de 80 Anos ou mais , Peptídeos beta-Amiloides/metabolismo , Animais , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Quelantes/síntese química , Quelantes/química , Quelantes/metabolismo , Complexos de Coordenação/síntese química , Complexos de Coordenação/metabolismo , Feminino , Fluorescência , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/metabolismo , Humanos , Iminoácidos/síntese química , Iminoácidos/química , Iminoácidos/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos ICR , Estrutura Molecular , Emaranhados Neurofibrilares/metabolismo , Emaranhados Neurofibrilares/patologia , Compostos de Organotecnécio/síntese química , Compostos de Organotecnécio/metabolismo , Fragmentos de Peptídeos/metabolismo , Quinoxalinas/síntese química , Quinoxalinas/metabolismo , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/química , Compostos Radiofarmacêuticos/metabolismo , Rênio/química , Distribuição Tecidual
16.
Nat Commun ; 10(1): 2394, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31160584

RESUMO

To understand the molecular processes that link Aß amyloidosis, tauopathy and neurodegeneration, we screened for tau-interacting proteins by immunoprecipitation/LC-MS. We identified the carboxy-terminal PDZ ligand of nNOS (CAPON) as a novel tau-binding protein. CAPON is an adaptor protein of neuronal nitric oxide synthase (nNOS), and activated by the N-methyl-D-aspartate receptor. We observed accumulation of CAPON in the hippocampal pyramidal cell layer in the AppNL-G-F -knock-in (KI) brain. To investigate the effect of CAPON accumulation on Alzheimer's disease (AD) pathogenesis, CAPON was overexpressed in the brain of AppNL-G-F mice crossbred with MAPT (human tau)-KI mice. This produced significant hippocampal atrophy and caspase3-dependent neuronal cell death in the CAPON-expressing hippocampus, suggesting that CAPON accumulation increases neurodegeneration. CAPON expression also induced significantly higher levels of phosphorylated, oligomerized and insoluble tau. In contrast, CAPON deficiency ameliorated the AD-related pathological phenotypes in tauopathy model. These findings suggest that CAPON could be a druggable AD target.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Doença de Alzheimer/metabolismo , Hipocampo/metabolismo , Agregação Patológica de Proteínas/metabolismo , Células Piramidais/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Precursor de Proteína beta-Amiloide/genética , Animais , Atrofia , Caspase 3/metabolismo , Morte Celular , Cromatografia Líquida , Modelos Animais de Doenças , Técnicas de Introdução de Genes , Hipocampo/patologia , Humanos , Imunoprecipitação , Espectrometria de Massas , Camundongos , Neurônios/metabolismo , Neurônios/patologia , Agregação Patológica de Proteínas/patologia , Células Piramidais/patologia , Tauopatias , Proteínas tau/metabolismo
17.
Nat Commun ; 10(1): 2493, 2019 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-31175300

RESUMO

Tauopathies are neurodegenerative diseases characterized by intracellular amyloid deposits of tau protein. Missense mutations in the tau gene (MAPT) correlate with aggregation propensity and cause dominantly inherited tauopathies, but their biophysical mechanism driving amyloid formation is poorly understood. Many disease-associated mutations localize within tau's repeat domain at inter-repeat interfaces proximal to amyloidogenic sequences, such as 306VQIVYK311. We use cross-linking mass spectrometry, recombinant protein and synthetic peptide systems, in silico modeling, and cell models to conclude that the aggregation-prone 306VQIVYK311 motif forms metastable compact structures with its upstream sequence that modulates aggregation propensity. We report that disease-associated mutations, isomerization of a critical proline, or alternative splicing are all sufficient to destabilize this local structure and trigger spontaneous aggregation. These findings provide a biophysical framework to explain the basis of early conformational changes that may underlie genetic and sporadic tau pathogenesis.


Assuntos
Agregação Patológica de Proteínas/genética , Tauopatias/genética , Proteínas tau/genética , Motivos de Aminoácidos/genética , Simulação por Computador , Células HEK293 , Humanos , Espectrometria de Massas , Microscopia Eletrônica de Transmissão , Mutação de Sentido Incorreto , Agregação Patológica de Proteínas/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestrutura , Proteínas tau/metabolismo , Proteínas tau/ultraestrutura
18.
JAMA ; 321(23): 2316-2325, 2019 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-31211344

RESUMO

Importance: A National Institute on Aging and Alzheimer's Association workgroup proposed a research framework for Alzheimer disease in which biomarker classification of research participants is labeled AT(N) for amyloid, tau, and neurodegeneration biomarkers. Objective: To determine the associations between AT(N) biomarker profiles and memory decline in a population-based cohort of individuals without dementia age 60 years or older, and to determine whether biomarkers provide incremental prognostic value beyond more readily available clinical and genetic information. Design, Setting, and Participants: Population-based cohort study of cognitive aging in Olmsted County, Minnesota, that included 480 nondemented Mayo Clinic Study of Aging participants who had a clinical evaluation and amyloid positron emission tomography (PET) (A), tau PET (T), and magnetic resonance imaging (MRI) cortical thickness (N) measures between April 16, 2015, and November 1, 2017, and at least 1 clinical evaluation follow-up by November 12, 2018. Exposures: Age, sex, education, cardiovascular and metabolic conditions score, APOE genotype, and AT(N) biomarker profiles. Each of A, T, or (N) can be abnormal (+) or normal (-), resulting in 8 AT(N) profiles. Main Outcomes and Measures: Primary outcome was a composite memory score measured longitudinally at 15-month intervals. Analyses measured the associations between predictor variables and the memory score, and whether AT(N) biomarker profiles significantly improved prediction of memory z score rates of change beyond a model with clinical and genetic variables only. Results: Participants were followed up for a median of 4.8 years (interquartile range [IQR], 3.8-5.1) and 44% were women (211/480). Median (IQR) ages ranged from 67 years (65-73) in the A-T-(N)- group to 83 years (76-87) in the A+T+(N)+ group. Of the participants, 92% (441/480) were cognitively unimpaired but the A+T+(N)+ group had the largest proportion of mild cognitive impairment (30%). AT(N) biomarkers improved the prediction of memory performance over a clinical model from an R2 of 0.26 to 0.31 (P < .001). Memory declined fastest in the A+T+(N)+, A+T+(N)-, and A+T-(N)+ groups compared with the other 5 AT(N) groups (P = .002). Estimated rates of decline in the 3 fastest declining groups were -0.13 (95% CI, -0.17 to -0.09), -0.10 (95% CI, -0.16 to -0.05), and -0.10 (95% CI, -0.13 to -0.06) z score units per year, respectively, for an 85-year-old APOE ε4 noncarrier. Conclusions and Relevance: Among older persons without baseline dementia followed for a median of 4.8 years, a prediction model that included amyloid PET, tau PET, and MRI cortical thickness resulted in a small but statistically significant improvement in predicting memory decline over a model with more readily available clinical and genetic variables. The clinical importance of this difference is uncertain.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Apolipoproteínas E/genética , Encéfalo/metabolismo , Disfunção Cognitiva/metabolismo , Imagem por Ressonância Magnética , Tomografia por Emissão de Pósitrons , Proteínas tau/metabolismo , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/metabolismo , Disfunção Cognitiva/diagnóstico por imagem , Estudos de Coortes , Demência , Progressão da Doença , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade
19.
Med Sci Monit ; 25: 3329-3335, 2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31056537

RESUMO

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of ß-amyloid peptide 1-42 and phosphorylation of tau protein in the brain. Thus far, the transfer mechanism of these cytotoxic proteins between nerve cells remains unclear. Recent studies have shown that nanoscale extracellular vesicles (exosomes) originating from cells may play important roles in this transfer process. In addition, several genetic materials and proteins are also involved in intercellular communication by the secretion of the exosomes. That proposes novel avenues for early diagnosis and biological treatment in AD, based on exosome detection and intervention. In this review, exosome-related pathways of cytotoxic protein intercellular transfer in AD, and the effect of membrane proteins on exosomes targeting cells are first introduced. The advances in exosome-related biomarker detection in AD are summarized. Finally, the advantages and challenges of reducing cytotoxic protein accumulation via exosomal intervention for AD treatment are discussed. It is envisaged that future research in exosomes may well provide new insights into the pathogenesis, diagnosis, and treatment of AD.


Assuntos
Doença de Alzheimer/patologia , Exossomos/patologia , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/metabolismo , Doença de Alzheimer/terapia , Biomarcadores/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Exossomos/metabolismo , Humanos , Fosforilação , Proteínas tau/metabolismo
20.
Invest Ophthalmol Vis Sci ; 60(6): 2380-2387, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-31141609

RESUMO

Purpose: To determine whether tauopathies are associated with impaired autophagy and involved in the death of retinal ganglion cells (RGCs) of rats from an optic nerve crush (ONC). Methods: Short interfering RNA (siRNA) of the tau gene (si-Tau) or nontargeting siRNA (si-NC) was injected intravitreally 48 hours prior to ONC. The effects of silencing the tau gene on neuroprotection were determined by the number of Tuj-1-stained RGCs on days 7 and 14 after the ONC. The changes in the expressions of phosphorylated tau, P62, and LC3B were determined by immunoblots and immunohistochemistry on day 7. Results: Autophagy was impaired in the retina on day 7 after the ONC as the P62 level increased by 3.1-fold from the sham control level with a reduction in the ratio LC3B2/LC3B1. There was a 2.1-fold increase of phosphorylated tau (ser 396) in the retina, and si-Tau depressed the increase by 1.3-fold (n = 3 each). The expressions of tau and P62 were well colocalized. They were observed in the somas of RGCs and retinal nerve fibers (RNFs), and these expressions were increased after the ONC. Pretreatment by si-Tau showed significant protection in the number of RGCs after the ONC. Specifically, the density of RGCs was 540 ± 74.5 cells/mm2 on day 14 in the si-NC group, while the level was maintained at 1321 ± 192 cells/mm2 in the si-Tau group (n = 4 each). Conclusions: Silencing the tau gene is neuroprotective, and tauopathies may be involved in the death of RGCs after ONC. Impaired autophagy may be involved in ONC-induced tauopathies.


Assuntos
Autofagia/fisiologia , Compressão Nervosa , Neuroproteção/fisiologia , Traumatismos do Nervo Óptico/fisiopatologia , Células Ganglionares da Retina/fisiologia , Proteínas tau/fisiologia , Animais , Sobrevivência Celular/fisiologia , Modelos Animais de Doenças , Inativação Gênica , Masculino , Ratos , Proteínas tau/metabolismo
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