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1.
Transl Psychiatry ; 9(1): 180, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31371701

RESUMO

Anorexia nervosa (AN) is a severe psychiatric disorder with high mortality and, to a large extent, unknown pathophysiology. Structural brain differences, such as global or focal reductions in grey or white matter volumes, as well as enlargement of the sulci and the ventricles, have repeatedly been observed in individuals with AN. However, many of the documented aberrances normalize with weight recovery, even though some studies show enduring changes. To further explore whether AN is associated with neuronal damage, we analysed the levels of neurofilament light chain (NfL), a marker reflecting ongoing neuronal injury, in plasma samples from females with AN, females recovered from AN (AN-REC) and normal-weight age-matched female controls (CTRLS). We detected significantly increased plasma levels of NfL in AN vs CTRLS (medianAN = 15.6 pg/ml, IQRAN = 12.1-21.3, medianCTRL = 9.3 pg/ml, IQRCTRL = 6.4-12.9, and p < 0.0001), AN vs AN-REC (medianAN-REC = 11.1 pg/ml, IQRAN-REC = 8.6-15.5, and p < 0.0001), and AN-REC vs CTRLS (p = 0.004). The plasma levels of NfL are negatively associated with BMI overall samples (ß (±se) = -0.62 ± 0.087 and p = 6.9‧10-12). This indicates that AN is associated with neuronal damage that partially normalizes with weight recovery. Further studies are needed to determine which brain areas are affected, and potential long-term sequelae.

2.
Biol Psychiatry ; 86(2): 110-119, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30686506

RESUMO

BACKGROUND: Genetic risk for bipolar disorder (BD) is conferred through many common alleles, while a role for rare copy number variants (CNVs) is less clear. Subtypes of BD including schizoaffective disorder bipolar type (SAB), bipolar I disorder (BD I), and bipolar II disorder (BD II) differ according to the prominence and timing of psychosis, mania, and depression. The genetic factors contributing to the combination of symptoms among these subtypes are poorly understood. METHODS: Rare large CNVs were analyzed in 6353 BD cases (3833 BD I [2676 with psychosis, 850 without psychosis, and 307 with unknown psychosis history], 1436 BD II, 579 SAB, and 505 BD not otherwise specified) and 8656 controls. CNV burden and a polygenic risk score (PRS) for schizophrenia were used to evaluate the relative contributions of rare and common variants to risk of BD, BD subtypes, and psychosis. RESULTS: CNV burden did not differ between BD and controls when treated as a single diagnostic entity. However, burden in SAB was increased relative to controls (p = .001), BD I (p = .0003), and BD II (p = .0007). Burden and schizophrenia PRSs were increased in SAB compared with BD I with psychosis (CNV p = .0007, PRS p = .004), and BD I without psychosis (CNV p = .0004, PRS p = 3.9 × 10-5). Within BD I, psychosis was associated with increased schizophrenia PRSs (p = .005) but not CNV burden. CONCLUSIONS: CNV burden in BD is limited to SAB. Rare and common genetic variants may contribute differently to risk for psychosis and perhaps other classes of psychiatric symptoms.

3.
Contemp Clin Trials ; 74: 61-69, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30287268

RESUMO

BACKGROUND: Genetic factors contribute to anorexia nervosa (AN); and the first genome-wide significant locus has been identified. We describe methods and procedures for the Anorexia Nervosa Genetics Initiative (ANGI), an international collaboration designed to rapidly recruit 13,000 individuals with AN and ancestrally matched controls. We present sample characteristics and the utility of an online eating disorder diagnostic questionnaire suitable for large-scale genetic and population research. METHODS: ANGI recruited from the United States (US), Australia/New Zealand (ANZ), Sweden (SE), and Denmark (DK). Recruitment was via national registers (SE, DK); treatment centers (US, ANZ, SE, DK); and social and traditional media (US, ANZ, SE). All cases had a lifetime AN diagnosis based on DSM-IV or ICD-10 criteria (excluding amenorrhea). Recruited controls had no lifetime history of disordered eating behaviors. To assess the positive and negative predictive validity of the online eating disorder questionnaire (ED100K-v1), 109 women also completed the Structured Clinical Interview for DSM-IV (SCID), Module H. RESULTS: Blood samples and clinical information were collected from 13,363 individuals with lifetime AN and from controls. Online diagnostic phenotyping was effective and efficient; the validity of the questionnaire was acceptable. CONCLUSIONS: Our multi-pronged recruitment approach was highly effective for rapid recruitment and can be used as a model for efforts by other groups. High online presence of individuals with AN rendered the Internet/social media a remarkably effective recruitment tool in some countries. ANGI has substantially augmented Psychiatric Genomics Consortium AN sample collection. ANGI is a registered clinical trial: clinicaltrials.govNCT01916538; https://clinicaltrials.gov/ct2/show/NCT01916538?cond=Anorexia+Nervosa&draw=1&rank=3.

4.
PLoS Comput Biol ; 14(5): e1006105, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29758032

RESUMO

A common goal in data-analysis is to sift through a large data-matrix and detect any significant submatrices (i.e., biclusters) that have a low numerical rank. We present a simple algorithm for tackling this biclustering problem. Our algorithm accumulates information about 2-by-2 submatrices (i.e., 'loops') within the data-matrix, and focuses on rows and columns of the data-matrix that participate in an abundance of low-rank loops. We demonstrate, through analysis and numerical-experiments, that this loop-counting method performs well in a variety of scenarios, outperforming simple spectral methods in many situations of interest. Another important feature of our method is that it can easily be modified to account for aspects of experimental design which commonly arise in practice. For example, our algorithm can be modified to correct for controls, categorical- and continuous-covariates, as well as sparsity within the data. We demonstrate these practical features with two examples; the first drawn from gene-expression analysis and the second drawn from a much larger genome-wide-association-study (GWAS).


Assuntos
Algoritmos , Bases de Dados Genéticas , Perfilação da Expressão Gênica/métodos , Estudo de Associação Genômica Ampla/métodos , Transtorno Bipolar/genética , Neoplasias da Mama/genética , Análise por Conglomerados , Feminino , Humanos , Masculino
5.
Neuropharmacology ; 135: 455-463, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29608920

RESUMO

The metabotropic glutamate receptor 5 (mGluR5) is a target for drug development and for imaging studies of the glutamate system in neurological and psychiatric disorders. [11C]AZD9272 is a selective mGluR5 PET radioligand that is structurally different from hitherto applied mGluR5 radioligands. In the present investigation we compared the binding patterns of radiolabeled AZD9272 and other mGluR5 radioligands in the non-human primate (NHP) brain. PET studies were undertaken using [11C]AZD9272 and the commonly applied mGluR5 radioligand [11C]ABP688. Autoradiography studies were performed in vitro using [3H]AZD9272 and the standard mGluR5 radioligands [3H]M-MTEP and [3H]ABP688 in NHP tissue. Competition binding studies were undertaken in vivo and in vitro using different mGluR5 selective compounds as inhibitors. In comparison to other mGluR5 radioligands radiolabeled AZD9272 displayed a distinct regional distribution pattern with high binding in ventral striatum, midbrain, thalamus and cerebellum. While the binding of [11C]AZD9272 was almost completely inhibited by the structurally unique mGluR5 compound fenobam (2.0 mg/kg; 98% occupancy), it was only partially inhibited (46% and 20%, respectively) by the mGluR5 selective compounds ABP688 and MTEP, at a dose (2.0 mg/kg) expected to saturate the mGluR5. Autoradiography studies using [3H]AZD9272 confirmed a distinct pharmacologic profile characterized by preferential sensitivity to fenobam. The distinctive binding in ventral striato-pallido-thalamic circuits and shared pharmacologic profile with the pro-psychotic compound fenobam warrants further examination of [11C]AZD9272 for potential application in psychiatric neuroimaging studies.

6.
J Pharmacol Exp Ther ; 358(3): 464-71, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27402278

RESUMO

Positron emission tomography (PET) is widely applied in central nervous system (CNS) drug development for assessment of target engagement in vivo. As the majority of PET investigations have addressed drug interaction at a single binding site, findings of multitarget engagement have been less frequently reported and have often been inconsistent with results obtained in vitro. AZD3676 [N,N-dimethyl-7-(4-(2-(pyridin-2-yl)ethyl)piperazin-1-yl) benzofuran-2-carboxamide] is a novel combined serotonin (5-hydroxytryptamine) 5-HT1A and 5-HT1B receptor antagonist that was developed for the treatment of cognitive impairment in Alzheimer's disease. Here, we evaluated the properties of AZD3676 as a CNS drug by combining in vitro and ex vivo radioligand binding techniques, behavioral pharmacology in rodents, and PET imaging in nonhuman primates. Target engagement in the nonhuman primate brain was assessed in PET studies by determination of drug-induced occupancy using receptor-selective radioligands. AZD3676 showed preclinical properties consistent with CNS drug potential, including nanomolar receptor affinity and efficacy in rodent models of learning and memory. In PET studies of the monkey brain, AZD3676 inhibited radioligand binding in a dose-dependent manner with similar affinity at both receptors. The equally high affinity at 5-HT1A and 5-HT1B receptors as determined in vivo was not predicted from corresponding estimates obtained in vitro, suggesting more than 10-fold selectivity for 5-HT1A versus 5-HT1B receptors. These findings support the further integrated use of PET for confirmation of multitarget occupancy of CNS drugs. Importantly, earlier introduction of PET studies in nonhuman primates may reduce future development costs and the requirement for animal experiments in preclinical CNS drug development programs.


Assuntos
Benzofuranos/metabolismo , Benzofuranos/farmacologia , Piperazinas/metabolismo , Piperazinas/farmacologia , Tomografia por Emissão de Pósitrons , Psicotrópicos/metabolismo , Psicotrópicos/farmacologia , Quinazolinas/metabolismo , Quinazolinas/farmacologia , Animais , Proteínas Sanguíneas/metabolismo , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/fisiologia , Humanos , Macaca fascicularis , Memória/efeitos dos fármacos , Camundongos , Receptor 5-HT1A de Serotonina/metabolismo , Receptor 5-HT1B de Serotonina/metabolismo , Antagonistas do Receptor 5-HT1 de Serotonina/metabolismo , Antagonistas do Receptor 5-HT1 de Serotonina/farmacologia
7.
Mol Psychiatry ; 21(9): 1290-7, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26503763

RESUMO

Lithium is the mainstay prophylactic treatment for bipolar disorder (BD), but treatment response varies considerably across individuals. Patients who respond well to lithium treatment might represent a relatively homogeneous subtype of this genetically and phenotypically diverse disorder. Here, we performed genome-wide association studies (GWAS) to identify (i) specific genetic variations influencing lithium response and (ii) genetic variants associated with risk for lithium-responsive BD. Patients with BD and controls were recruited from Sweden and the United Kingdom. GWAS were performed on 2698 patients with subjectively defined (self-reported) lithium response and 1176 patients with objectively defined (clinically documented) lithium response. We next conducted GWAS comparing lithium responders with healthy controls (1639 subjective responders and 8899 controls; 323 objective responders and 6684 controls). Meta-analyses of Swedish and UK results revealed no significant associations with lithium response within the bipolar subjects. However, when comparing lithium-responsive patients with controls, two imputed markers attained genome-wide significant associations, among which one was validated in confirmatory genotyping (rs116323614, P=2.74 × 10(-8)). It is an intronic single-nucleotide polymorphism (SNP) on chromosome 2q31.2 in the gene SEC14 and spectrin domains 1 (SESTD1), which encodes a protein involved in regulation of phospholipids. Phospholipids have been strongly implicated as lithium treatment targets. Furthermore, we estimated the proportion of variance for lithium-responsive BD explained by common variants ('SNP heritability') as 0.25 and 0.29 using two definitions of lithium response. Our results revealed a genetic variant in SESTD1 associated with risk for lithium-responsive BD, suggesting that the understanding of BD etiology could be furthered by focusing on this subtype of BD.


Assuntos
Transtorno Bipolar/genética , Proteínas de Transporte/genética , Adulto , Antimaníacos/uso terapêutico , Biomarcadores Farmacológicos/sangue , Transtorno Bipolar/metabolismo , Proteínas de Transporte/metabolismo , Feminino , Predisposição Genética para Doença/genética , Variação Genética , Estudo de Associação Genômica Ampla/métodos , Genótipo , Humanos , Lítio/metabolismo , Lítio/uso terapêutico , Compostos de Lítio/uso terapêutico , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Fatores de Risco , Autorrelato , Suécia , Reino Unido
8.
ACS Chem Neurosci ; 7(2): 177-84, 2016 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-26529287

RESUMO

UNLABELLED: The histamine type 3 receptor (H3) is a G protein-coupled receptor implicated in several disorders of the central nervous system. Herein, we describe the radiolabeling and preclinical evaluation of a candidate radioligand for the H3 receptor, 4-(1S,2S)-2-(4-cyclobutylpiperazine-1-carbonyl)cyclopropyl]-N-methyl-benzamide (5), and its comparison with one of the frontrunner radioligands for H3 imaging, namely, GSK189254 (1). Compounds 1 and 5 were radiolabeled with tritium and carbon-11 for in vitro and in vivo imaging experiments. The in vitro binding of [(3)H]1 and [(3)H]5 was examined by (i) saturation binding to rat and nonhuman primate brain tissue homogenate and (ii) in vitro autoradiography on tissue sections from rat, guinea pig, and human brain. The in vivo binding of [(11)C]1 and [(11)C]5 was examined by PET imaging in mice and nonhuman primates. Bmax values obtained from Scatchard analysis of [(3)H]1 and [(3)H]5 binding were in good agreement. Autoradiography with [(3)H]5 on rat, guinea pig, and human brain slices showed specific binding in regions known to be enhanced in H3 receptors, a high degree of colocalization with [(3)H]1, and virtually negligible nonspecific binding in tissue. PET measurements in mice and nonhuman primates demonstrated that [(11)C]5 binds specifically and reversibly to H3 receptors in vivo with low nonspecific binding in brain tissue. Whereas [(11)C]1 showed similar binding characteristics in vivo, the binding kinetics appeared faster for [(11)C]5 than for [(11)C]1. CONCLUSIONS: [(11)C]5 has suitable properties for quantification of H3 receptors in nonhuman primate brain and has the potential to offer improved binding kinetics in man compared to [(11)C]1.


Assuntos
Encéfalo/efeitos dos fármacos , Encéfalo/diagnóstico por imagem , Radioisótopos de Carbono/farmacocinética , Histamínicos/farmacologia , Receptores Histamínicos H3/metabolismo , Doença de Alzheimer/patologia , Animais , Autorradiografia , Benzamidas/química , Benzamidas/farmacologia , Benzazepinas/farmacologia , Relação Dose-Resposta a Droga , Feminino , Cobaias , Haplorrinos , Histamínicos/química , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Niacinamida/análogos & derivados , Niacinamida/farmacologia , Piperazinas/química , Piperazinas/farmacologia , Ligação Proteica/efeitos dos fármacos , Ratos , Reprodutibilidade dos Testes , Fatores de Tempo , Distribuição Tecidual/efeitos dos fármacos , Distribuição Tecidual/fisiologia , Trítio/farmacocinética
9.
J Neurochem ; 132(4): 477-86, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25156639

RESUMO

Aggregation of amyloid beta (Aß) peptides and the subsequent neural plaque formation is a central aspect of Alzheimer's disease. Various strategies to reduce Aß load in the brain are therefore intensely pursued. It has been hypothesized that reducing Aß peptides in the periphery, that is in organs outside the brain, would be a way to diminish Aß levels and plaque load in the brain. In this report, we put this peripheral sink hypothesis to test by investigating how selective inhibition of Aß production in the periphery using a ß-secretase (BACE)1 inhibitor or reduced BACE1 gene dosage affects Aß load in the brain. Selective inhibition of peripheral BACE1 activity in wild-type mice or mice over-expressing amyloid precursor protein (APPswe transgenic mice; Tg2576) reduced Aß levels in the periphery but not in the brain, not even after chronic treatment over several months. In contrast, a BACE1 inhibitor with improved brain disposition reduced Aß levels in both brain and periphery already after acute dosing. Mice heterozygous for BACE1, displayed a 62% reduction in plasma Aß40, whereas brain Aß40 was only lowered by 11%. These data suggest that reduction of Aß in the periphery is not sufficient to reduce brain Aß levels and that BACE1 is not the rate-limiting enzyme for Aß processing in the brain. This provides evidence against the peripheral sink hypothesis and suggests that a decrease in Aß via BACE1 inhibition would need to be carried out in the brain. Aggregation of amyloid beta (Aß) peptides in the brain is a central aspect of Alzheimer's disease. In this study, we demonstrate that inhibition of Aß formation by BACE1 inhibitors needs to be carried out in the brain and that reduction of Aß in the periphery is not sufficient to reduce brain Aß levels. This information is useful for developing future Aß-targeting therapies for Alzheimer's disease.


Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/biossíntese , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Ácido Aspártico Endopeptidases/metabolismo , Encéfalo/enzimologia , Animais , Encéfalo/efeitos dos fármacos , Células CACO-2 , Cricetinae , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Feminino , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos
10.
Proc Natl Acad Sci U S A ; 111(14): 5409-14, 2014 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-24706865

RESUMO

One hallmark of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE) is infiltration of leukocytes into the CNS, where chemokines and their receptors play a major mediatory role. CX3CR1 is a chemokine receptor involved in leukocyte adhesion and migration and hence a mediator of immune defense reactions. The role of CX3CR1 in MS and EAE pathogenesis however remains to be fully assessed. Here, we demonstrate CX3CR1 mRNA expression on inflammatory cells within active plaque areas in MS brain autopsies. To test whether blocking CNS infiltration of peripheral leukocytes expressing CX3CR1 would be a suitable treatment strategy for MS, we developed a selective, high-affinity inhibitor of CX3CR1 (AZD8797). The compound is active outside the CNS and AZD8797 treatment in Dark Agouti rats with myelin oligodendrocyte glycoprotein-induced EAE resulted in reduced paralysis, CNS pathology, and incidence of relapses. The compound is effective when starting treatment before onset, as well as after the acute phase. This treatment strategy is mechanistically similar to, but more restricted than, current very late antigen-4-directed approaches that have significant side effects. We suggest that blocking CX3CR1 on leukocytes outside the CNS could be an alternative approach to treat MS.


Assuntos
Encéfalo/metabolismo , Modelos Animais de Doenças , Esclerose Múltipla/patologia , Receptores de Quimiocinas/antagonistas & inibidores , Animais , Receptor 1 de Quimiocina CX3C , Doença Crônica , Ratos , Receptores de Quimiocinas/metabolismo , Recidiva
11.
Eur J Nucl Med Mol Imaging ; 40(4): 580-93, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23324871

RESUMO

PURPOSE: The aim of this study was to evaluate AZD2995 side by side with AZD2184 as novel PET radioligands for imaging of amyloid-ß in Alzheimer's disease (AD). METHODS: In vitro binding of tritium-labelled AZD2995 and AZD2184 was studied and compared with that of the established amyloid-ß PET radioligand PIB. Subsequently, a first-in-human in vivo PET study was performed using [(11)C]AZD2995 and [(11)C]AZD2184 in three healthy control subjects and seven AD patients. RESULTS: AZD2995, AZD2184 and PIB were found to share the same binding site to amyloid-ß. [(3)H]AZD2995 had the highest signal-to-background ratio in brain tissue from patients with AD as well as in transgenic mice. However, [(11)C]AZD2184 had superior imaging properties in PET, as shown by larger effect sizes comparing binding potential values in cortical regions of AD patients and healthy controls. Nevertheless, probably due to a lower amount of nonspecific binding, the group separation of the distribution volume ratio values of [(11)C]AZD2995 was greater in areas with lower amyloid-ß load, e.g. the hippocampus. CONCLUSION: Both AZD2995 and AZD2184 detect amyloid-ß with high affinity and specificity and also display a lower degree of nonspecific binding than that reported for PIB. Overall [(11)C]AZD2184 seems to be an amyloid-ß radioligand with higher uptake and better group separation when compared to [(11)C]AZD2995. However, the very low nonspecific binding of [(11)C]AZD2995 makes this radioligand potentially interesting as a tool to study minute levels of amyloid-ß. This sensitivity may be important in investigating, for example, early prodromal stages of AD or in the longitudinal study of a disease modifying therapy.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Peptídeos beta-Amiloides/análise , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/genética , Aminopiridinas/farmacocinética , Animais , Benzotiazóis/farmacocinética , Benzoxazóis/farmacocinética , Sítios de Ligação , Encéfalo/diagnóstico por imagem , Radioisótopos de Carbono , Estudos de Casos e Controles , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Camundongos , Camundongos Transgênicos , Pessoa de Meia-Idade , Ligação Proteica , Ensaio Radioligante , Compostos Radiofarmacêuticos/farmacocinética , Sensibilidade e Especificidade
12.
J Neurosci ; 32(48): 17297-305, 2012 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-23197721

RESUMO

γ-Secretase inhibition represents a major therapeutic strategy for lowering amyloid ß (Aß) peptide production in Alzheimer's disease (AD). Progress toward clinical use of γ-secretase inhibitors has, however, been hampered due to mechanism-based adverse events, primarily related to impairment of Notch signaling. The γ-secretase inhibitor MRK-560 represents an exception as it is largely tolerable in vivo despite displaying only a small selectivity between Aß production and Notch signaling in vitro. In exploring the molecular basis for the observed tolerability, we show that MRK-560 displays a strong preference for the presenilin 1 (PS1) over PS2 subclass of γ-secretases and is tolerable in wild-type mice but causes dose-dependent Notch-related side effect in PS2-deficient mice at drug exposure levels resulting in a substantial decrease in brain Aß levels. This demonstrates that PS2 plays an important role in mediating essential Notch signaling in several peripheral organs during pharmacological inhibition of PS1 and provide preclinical in vivo proof of concept for PS2-sparing inhibition as a novel, tolerable and efficacious γ-secretase targeting strategy for AD.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Peptídeos beta-Amiloides/metabolismo , Encéfalo/efeitos dos fármacos , Presenilina-2/metabolismo , Doença de Alzheimer/metabolismo , Animais , Encéfalo/metabolismo , Camundongos , Presenilina-2/genética , Receptores Notch/genética , Receptores Notch/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Sulfonamidas/farmacologia , Sulfonamidas/uso terapêutico
13.
J Biol Chem ; 287(39): 32640-50, 2012 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-22851182

RESUMO

The γ-secretase complex is an appealing drug target when the therapeutic strategy is to alter amyloid-ß peptide (Aß) aggregation in Alzheimer disease. γ-Secretase is directly involved in Aß formation and determines the pathogenic potential of Aß by generating the aggregation-prone Aß42 peptide. Because γ-secretase mediates cleavage of many substrates involved in cell signaling, such as the Notch receptor, it is crucial to sustain these pathways while altering the Aß secretion. A way of avoiding interference with the physiological function of γ-secretase is to use γ-secretase modulators (GSMs) instead of inhibitors of the enzyme. GSMs modify the Aß formation from producing the amyloid-prone Aß42 variant to shorter and less amyloidogenic Aß species. The modes of action of GSMs are not fully understood, and even though the pharmacology of GSMs has been thoroughly studied regarding Aß generation, knowledge is lacking about their effects on other substrates, such as Notch. Here, using immunoprecipitation followed by MALDI-TOF MS analysis, we found that two novel, second generation GSMs modulate both Notch ß and Aß production. Moreover, by correlating S3-specific Val-1744 cleavage of Notch intracellular domain (Notch intracellular domain) to total Notch intracellular domain levels using immunocytochemistry, we also demonstrated that Notch intracellular domain is not modulated by the compounds. Interestingly, two well characterized, nonsteroidal anti-inflammatory drugs (nonsteroidal anti-inflammatory drug), R-flurbiprofen and sulindac sulfide, affect only Aß and not Notch ß formation, indicating that second generation GSMs and nonsteroidal anti-inflammatory drug-based GSMs have different modes of action regarding Notch processing.


Assuntos
Secretases da Proteína Precursora do Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Amiloide/metabolismo , Anti-Inflamatórios não Esteroides/farmacologia , Flurbiprofeno/farmacologia , Receptores Notch/metabolismo , Sulindaco/análogos & derivados , Amiloide/genética , Secretases da Proteína Precursora do Amiloide/genética , Precursor de Proteína beta-Amiloide/genética , Animais , Feminino , Células HEK293 , Humanos , Camundongos , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Processamento de Proteína Pós-Traducional/genética , Estrutura Terciária de Proteína , Receptores Notch/genética , Sulindaco/farmacologia
14.
Bioorg Med Chem Lett ; 22(13): 4332-7, 2012 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-22647721

RESUMO

The synthesis and SAR of new ß-amyloid binding agents are reported. Evaluation of important properties for achieving good signal-to-background ratio is described. Compounds 27, 33, and 36 displayed desirable lipophilic and pharmacokinetic properties. Compound 27 was further evaluated with autoradiographic studies in vitro on human brain tissue and in vivo in Tg2576 mice. Compound 27 showed an increased signal-to-background ratio compared to flutemetamol 4, indicating its suitability as PET ligand for ß-amyloid deposits in AD patients. The preparation of the corresponding (18)F-labeled PET radioligand of compound 27 is presented.


Assuntos
Aminopiridinas/síntese química , Peptídeos beta-Amiloides/química , Benzofuranos/química , Benzotiazóis/química , Benzoxazóis/química , Meios de Contraste/síntese química , Compostos Radiofarmacêuticos/síntese química , Doença de Alzheimer/diagnóstico , Aminopiridinas/farmacocinética , Peptídeos beta-Amiloides/metabolismo , Animais , Benzofuranos/síntese química , Benzofuranos/farmacocinética , Benzotiazóis/farmacocinética , Benzoxazóis/farmacocinética , Encéfalo/metabolismo , Meios de Contraste/farmacocinética , Radioisótopos de Flúor/química , Humanos , Camundongos , Camundongos Transgênicos , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos/farmacocinética , Relação Estrutura-Atividade
15.
J Biol Chem ; 287(15): 11810-9, 2012 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-22334705

RESUMO

γ-Secretase-mediated cleavage of amyloid precursor protein (APP) results in the production of Alzheimer disease-related amyloid-ß (Aß) peptides. The Aß42 peptide in particular plays a pivotal role in Alzheimer disease pathogenesis and represents a major drug target. Several γ-secretase modulators (GSMs), such as the nonsteroidal anti-inflammatory drugs (R)-flurbiprofen and sulindac sulfide, have been suggested to modulate the Alzheimer-related Aß production by targeting the APP. Here, we describe novel GSMs that are selective for Aß modulation and do not impair processing of Notch, EphB2, or EphA4. The GSMs modulate Aß both in cell and cell-free systems as well as lower amyloidogenic Aß42 levels in the mouse brain. Both radioligand binding and cellular cross-competition experiments reveal a competitive relationship between the AstraZeneca (AZ) GSMs and the established second generation GSM, E2012, but a noncompetitive interaction between AZ GSMs and the first generation GSMs (R)-flurbiprofen and sulindac sulfide. The binding of a (3)H-labeled AZ GSM analog does not co-localize with APP but overlaps anatomically with a γ-secretase targeting inhibitor in rodent brains. Combined, these data provide compelling evidence of a growing class of in vivo active GSMs, which are selective for Aß modulation and have a different mechanism of action compared with the original class of GSMs described.


Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Peptídeos beta-Amiloides/biossíntese , Precursor de Proteína beta-Amiloide/metabolismo , Azepinas/farmacologia , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Piranos/farmacologia , Piridinas/farmacologia , Pirimidinas/farmacologia , Alanina/análogos & derivados , Alanina/farmacologia , Secretases da Proteína Precursora do Amiloide/metabolismo , Animais , Azepinas/química , Ligação Competitiva , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Carbamatos/farmacologia , Sistema Livre de Células , Dibenzazepinas/farmacologia , Dipeptídeos/farmacologia , Interações de Medicamentos , Feminino , Flurbiprofeno/farmacologia , Cobaias , Células HEK293 , Humanos , Imidazóis/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Piperidinas/farmacologia , Ligação Proteica , Piranos/química , Piridinas/química , Pirimidinas/química , Ratos , Receptor EphA4/metabolismo , Receptor EphB2/metabolismo , Receptores Notch/metabolismo , Sulfonamidas/farmacologia , Sulindaco/análogos & derivados , Sulindaco/farmacologia
16.
J Neurochem ; 114(3): 784-94, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20477945

RESUMO

Positron emission tomography (PET) radioligands that bind selectively to beta-amyloid plaques (Abeta) are promising imaging tools aimed at supporting the diagnosis of Alzheimer's disease and the evaluation of new drugs aiming to modify amyloid plaque load. For extended clinical use, there is a particular need for PET tracers labeled with fluorine-18, a radionuclide with 110 min half-life allowing for central synthesis followed by wide distribution. The development of fluorinated radioligands is, however, challenging because of the lipophilic nature of aromatic fluorine, rendering fluorinated ligands more prone to have high non-specific white matter binding. We have here developed the new benzofuran-derived radioligand containing fluorine, AZD4694 that shows high affinity for beta-amyloid fibrils in vitro (K(d) = 2.3 +/- 0.3 nM). In cortical sections from human Alzheimer's disease brain [(3)H]AZD4694 selectively labeled beta-amyloid deposits in gray matter, whereas there was a lower level of non-displaceable binding in plaque devoid white matter. Administration of unlabeled AZD4694 to rat showed that it has a pharmacokinetic profile consistent with good PET radioligands, i.e., it quickly entered and rapidly cleared from normal rat brain tissue. Ex vivo binding data in aged Tg2576 mice after intravenous administration of [(3)H]AZD4694 showed selective binding to beta-amyloid deposits in a reversible manner. In Tg2576 mice, plaque bound [(3)H]AZD4694 could still be detected 80 min after i.v. administration. Taken together, the preclinical profile of AZD4694 suggests that fluorine-18 labeled AZD4694 may have potential for PET-visualization of cerebral beta-amyloid deposits in the living human brain.


Assuntos
Peptídeos beta-Amiloides/análise , Peptídeos beta-Amiloides/metabolismo , Benzofuranos/metabolismo , Compostos de Flúor , Radioisótopos de Flúor , Hidrocarbonetos Fluorados/metabolismo , Placa Amiloide/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Animais , Ligação Competitiva/fisiologia , Feminino , Humanos , Injeções Intraventriculares , Masculino , Camundongos , Camundongos Transgênicos , Placa Amiloide/metabolismo , Placa Amiloide/patologia , Ensaio Radioligante/métodos , Ratos , Ratos Sprague-Dawley
17.
Bioorg Med Chem Lett ; 20(6): 1976-80, 2010 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-20153963

RESUMO

The syntheses and SAR of new series of beta-amyloid binding agents are reported. The effort to optimize signal-to-background ratios for these ligands are described. Compounds 8, 21 and 30 displayed desirable lipophilicity and pharmacokinetic properties. Compounds 8 and 21 were evaluated with in vitro autoradiographic studies and in vivo in APP/PS1 transgenic mice. It is shown that it was possible to increase the signal-to-background ratios compared to PIB 1, as demonstrated by compounds 8 and 21.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Benzofuranos/síntese química , Benzofuranos/farmacocinética , Benzotiazóis/síntese química , Benzotiazóis/farmacocinética , Benzoxazóis/síntese química , Benzoxazóis/farmacocinética , Tomografia por Emissão de Pósitrons , Animais , Radioisótopos de Carbono , Meia-Vida , Camundongos , Camundongos Transgênicos , Ensaio Radioligante , Relação Estrutura-Atividade
18.
Biochem Biophys Res Commun ; 393(1): 21-7, 2010 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-20097169

RESUMO

beta-Secretase (BACE) is an aspartyl protease, which proteolytically processes amyloid precursor protein, making BACE an interesting pharmacological target in Alzheimer's disease. To study the enzymatic function of BACE, we mutated either of the two aspartic acid residues in the active site of BACE. This rendered BACE functionally inactive without affecting the degree of glycosylation or endosomal localization. In contrast, substituting both active site aspartic acid residues produced a functionally inactive, endoplasmic reticulum-retained and partially glycosylated BACE. Interestingly, co-expression of the two single active site mutants partially restored beta-site cleavage of amyloid precursor protein, and the restored activity was inhibited with similar dose-dependency and potency as wildtype BACE by a small molecule inhibitor raised against BACE. In sum, our data suggest that two different active site mutants can complement each other in a partially functional BACE dimer and mediate APP processing.


Assuntos
Doença de Alzheimer/enzimologia , Secretases da Proteína Precursora do Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Ácido Aspártico Endopeptidases/metabolismo , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Secretases da Proteína Precursora do Amiloide/genética , Animais , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Ácido Aspártico Endopeptidases/genética , Domínio Catalítico/genética , Interações Hidrofóbicas e Hidrofílicas , Camundongos , Camundongos Knockout , Mutação , Multimerização Proteica
19.
J Neurochem ; 108(5): 1177-86, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19141073

RESUMO

The presence of beta-amyloid plaques in brain is a hallmark of Alzheimer's disease (AD) and serves as a biomarker for confirmation of diagnosis postmortem. Positron emission tomography (PET) radioligands such as Pittsburgh compound B ([(11)C]-2-(3-fluoro-4-methylamino-phenyl)-benzothiazol-6-ol) (PIB) binds selectively to beta-amyloid and are promising new tools supporting the clinical diagnoses of AD. In addition, such methodology may be useful for evaluation of new drugs aiming at reduction of amyloid plaque load. The objective of this study is to develop a new amyloid selective PET radioligand with higher signal-to-background ratio when compared with existing amyloid PET ligands. The lead compound, AZD2184, (2-[6-(methylamino)pyridin-3-yl]-1,3-benzothiazol-6-ol) was found to have high affinity for amyloid fibrils in vitro (K(d): 8.4 +/- 1.0 nM). Two minutes after i.v. administration in rats, about 1% of the dose was in brain. In vitro autoradiography on cortical brain sections from amyloid-beta precursor protein/presenilin 1 (APP/PS1) mice and AD patients showed that while [(3)H]AZD2184 and [(3)H]PIB are mutually displaceable, [(3)H]AZD2184 displays a higher signal-to-background ratio primarily by virtue of lower background binding levels. The ratio of binding ability in prefrontal cortex (high plaque load) to subcortical white matter (background) was 4.5 for [(3)H]AZD2184 and 0.8 for [(3)H]PIB at 1 nM. In adjacent cortical sections from APP/PS1 mouse as well as from AD cortical tissue, [(3)H]AZD2184 and antibodies to human beta-amyloid labeled identical structures. In vivo administration of [(3)H]AZD2184 to APP/PS1 mice further showed that [(3)H]AZD2184 labels amyloid deposits with low non-specific background binding. Taken together, the pre-clinical profile of AZD2184 in relation to the reference ligand PIB, suggests that (11)C-labeled AZD2184 is a potential radioligand for PET-visualization of beta-amyloid deposits in the living human brain.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Encéfalo/metabolismo , Placa Amiloide/diagnóstico por imagem , Doença de Alzheimer/patologia , Aminopiridinas/metabolismo , Precursor de Proteína beta-Amiloide/genética , Compostos de Anilina/química , Compostos de Anilina/metabolismo , Animais , Autorradiografia , Benzotiazóis/metabolismo , Encéfalo/diagnóstico por imagem , Radioisótopos de Carbono/metabolismo , Proposta de Concorrência/métodos , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Mutação/genética , Tomografia por Emissão de Pósitrons/métodos , Presenilina-1/genética , Ligação Proteica/efeitos dos fármacos , Ensaio Radioligante/métodos , Ratos , Ratos Sprague-Dawley , Tiazóis/química , Tiazóis/metabolismo , Trítio/metabolismo
20.
J Comp Neurol ; 504(6): 680-9, 2007 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-17722032

RESUMO

It is generally accepted that the voltage-gated, tetrodotoxin-sensitive sodium channel, Na(V)1.7, is selectively expressed in peripheral ganglia. However, global deletion in mice of Na(V)1.7 leads to death shortly after birth (Nassar et al. [2004] Proc. Natl. Acad. Sci. U. S. A. 101:12706-12711), suggesting that this ion channel might be more widely expressed. To understand better the potential physiological function of this ion channel, we examined Na(V)1.7 expression in the rat by in situ hybridization and immunohistochemistry. As expected, highest mRNA expression levels are found in peripheral ganglia, and the protein is expressed within these ganglion cells and on the projections of these neurons in the central nervous system. Importantly, we found that Na(V)1.7 is present in discrete rat brain regions, and the unique distribution pattern implies a central involvement in endocrine and autonomic systems as well as analgesia. In addition, Na(V)1.7 expression was detected in the pituitary and adrenal glands. These results indicate that Na(V)1.7 is not only involved in the processing of sensory information but also participates in the regulation of autonomic and endocrine systems; more specifically, it could be implicated in such vital functions as fluid homeostasis and cardiovascular control.


Assuntos
Sistema Nervoso Autônomo/metabolismo , Sistema Endócrino/metabolismo , Canais de Sódio/metabolismo , Animais , Linhagem Celular Transformada , Sistema Nervoso Central/metabolismo , Humanos , Imuno-Histoquímica/métodos , Hibridização In Situ/métodos , Masculino , Canal de Sódio Disparado por Voltagem NAV1.7 , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Canais de Sódio/genética
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