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1.
Chem Commun (Camb) ; 55(91): 13725-13728, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31660558

RESUMO

In this communication, the mechanism of how surface chirality affects amyloid-ß (Aß) fibrillation was firstly unravelled at the molecular level: a chiral surface serves to control the 2D-diffusion and surface residence time of Aß molecules via the chiral recognition with Aß to allow precursor Aß to laterally diffuse and collide with each other for oligomerization and fibrillation. Surface chirality that shortens the surface residence time of Aß, for example, R-cysteine modification with carboxylic, secondary amine and thiol groups surrounding the chiral center, can retard Aß oligomerization and fibrillation. This work is essential to a deeper fundamental understanding of the effects of surface chirality on amyloidosis processes as well as the development of chiral materials to inhibit Aß fibrillation.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Amiloide/metabolismo , Fragmentos de Peptídeos/metabolismo , Amiloide/química , Peptídeos beta-Amiloides/química , Cisteína/química , Ligações de Hidrogênio , Microscopia de Força Atômica , Fragmentos de Peptídeos/química , Dióxido de Silício/química , Estereoisomerismo
2.
Immunogenetics ; 71(8-9): 519-530, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31520135

RESUMO

Human CD4+ T lymphocytes play an important role in inducing potent immune responses. T cells are activated and stimulated by peptides presented in human leucocyte antigen (HLA)-class II molecules. These HLA-class II molecules typically present peptides of between 12 and 20 amino acids in length. The region that interacts with the HLA molecule, designated as the peptide-binding core, is highly conserved in the residues which anchor the peptide to the molecule. In addition, as these peptides are the product of proteolytic cleavages, certain conserved residues may be expected at the N- and C-termini outside the binding core. To study whether similar conserved residues are present in different cell types, potentially harbouring different proteolytic enzymes, the ligandomes of HLA-DRB1*03:01/HLA-DRB > 1 derived from two different cell types (dendritic cells and EBV-transformed B cells) were identified with mass spectrometry and the binding core and N- and C-terminal residues of a total of 16,568 peptides were analysed using the frequencies of the amino acids in the human proteome. Similar binding motifs were found as well as comparable conservations in the N- and C-terminal residues. Furthermore, the terminal conservations of these ligandomes were compared to the N- and C-terminal conservations of the ligandome acquired from dendritic cells homozygous for HLA-DRB1*04:01. Again, comparable conservations were evident with only minor differences. Taken together, these data show that there are conservations in the terminal residues of peptides, presumably the result of the activity of proteases involved in antigen processing.


Assuntos
Linfócitos B/metabolismo , Células Dendríticas/metabolismo , Antígenos HLA-DR/classificação , Antígenos HLA-DR/metabolismo , Fragmentos de Peptídeos/metabolismo , Proteoma/metabolismo , Motivos de Aminoácidos , Linfócitos B/citologia , Células Cultivadas , Células Dendríticas/citologia , Humanos , Ligantes , Ligação Proteica
3.
Life Sci ; 233: 116749, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31412264

RESUMO

AIMS: Functional dyspepsia (FD) is very common worldwide with a high prevalence of 10%-30%, and it becomes a heavy burden to patients because of its hard to be cured. In our previous study, phenylethanoid glycosides were found to exist in Houpo, a traditional Chinese medicine commonly used for the treatment of abdominal distention, pain and dyspepsia. In the present study, the effect of magnoloside A (MA), a main phenylethanoid glycoside in Houpo, on FD was firstly evaluated and its potential mechanism was concluded. MATERIALS AND METHODS: MA was orally administered consequently for 3 weeks, and its effect on a FD rat model established through transient neonatal gastric irritation and mature alternate-day fasting was tested. Levels of brain-gut peptides and inflammatory factors in blood or tissues were determined by ELISA methods. Meanwhile, the gut microbiota was analyzed by 16S rRNA gene sequencing and short chain fat acids were determined by GC/MS. KEY FINDINGS: MA exhibited anti-FD activities by fastening the delayed gut emptying rate of FD rat and increasing the levels of gastrin, motilin, and calcitonin gene related protein; and decreasing the levels of 5-hydroxytryptamine, nitric oxide synthase, and vasoactive intestinal peptide. On the other hand, MA can modulate the composition of gut microbiota, resulting in the variation of the short chain fat acids. SIGNIFICANCE: MA ameliorated FD rats by modulating of the secretion of related brain-gut peptides and altering the composition of intestinal microbiota.


Assuntos
Encéfalo/metabolismo , Dispepsia/tratamento farmacológico , Microbioma Gastrointestinal , Trato Gastrointestinal/metabolismo , Glicosídeos/administração & dosagem , Fragmentos de Peptídeos/metabolismo , Administração Oral , Animais , Animais Recém-Nascidos , Dispepsia/metabolismo , Dispepsia/microbiologia , Esvaziamento Gástrico/efeitos dos fármacos , Glicosídeos/química , Magnolia/química , Masculino , Álcool Feniletílico/química , Ratos , Ratos Sprague-Dawley
4.
Cell Physiol Biochem ; 53(2): 413-428, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31415717

RESUMO

BACKGROUND/AIMS: Amyloid plaques, generated during the progression of Alzheimer's disease, cause major neurological deficits due to substantial cell toxicity and death. The underlying cause of plaque generation stems from cleavage of the amyloid precursor protein (APP) by ß-secretase (BACE1). A resulting amyloid-ß (Aß) fragment forms aggregates to produce the main constituent of a plaque. METHODS: Phage display and biopanning techniques were used to identify a 12-mer peptide that had a natural affinity for the BACE1 enzyme. The peptide was translated from phage DNA and synthetically produced. The peptide, at concentrations of 1nM, 10nM and 100nM, was used to confirm binding by direct assay. Non-specific binding to BACE2, renin and cathepsin D was tested by direct binding assay. A BACE1 activity assay was used to determine the peptide effect on cleavage of an APP substrate. Treatment of SY5Y cells with the peptide was used to determine toxicity and prevention of Aß40 and Aß42 production. RESULTS: After identification and synthetic production, the peptide exhibited a strong affinity for BACE1 at nanomolar concentrations in the direct assay. In case of non-specific binding to homologous BACE2, renin and cathepsin D, the peptide showed minor binding but was nullified when in solution with BACE1. The peptide addition to a BACE1 activity assay was able to significantly reduce the amount of substrate cleavage. SY5Y cells, when treated with the peptide, did not show any detrimental morphological changes while being able to reduce the production of natural Aß40 and Aß42. Even under stressed conditions (H2O2 treatment) where the Aß production was higher, the peptide was still able to significantly reduce the effect of BACE1 while not effecting cell viability. CONCLUSION: The identified peptide exhibited strong binding to BACE1 in vitro and was able to reduce production of Aß, suggesting a favourable BACE1 inhibitor for future refining and characterisation.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Peptídeos beta-Amiloides/antagonistas & inibidores , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Fragmentos de Peptídeos/antagonistas & inibidores , Peptídeos/farmacologia , Doença de Alzheimer/metabolismo , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Ácido Aspártico Endopeptidases/metabolismo , Linhagem Celular , Descoberta de Drogas , Inibidores Enzimáticos/metabolismo , Humanos , Fragmentos de Peptídeos/metabolismo , Peptídeos/metabolismo
5.
Arch Endocrinol Metab ; 63(4): 394-401, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31365627

RESUMO

OBJECTIVE: To measure type 1 serum amino-terminal propeptide procollagen (P1NP) and type 1 cross-linked C-terminal telopeptide collagen (CTX) before parathyroidectomy (PTX) in PHPT patients, correlating these measurements with bone mineral density (BMD) changes. SUBJECTS AND METHODS: 31 primary hyperparathyroidism (HPTP) were followed from diagnosis up to 12-18 months after surgery. Serum levels of calcium, parathyroid hormone (PTH) vitamin D, CTX, P1NP, and BMD were measured before and 1 year after surgery. RESULTS: One year after PTX, the mean BMD increased by 8.6%, 5.5%, 5.5%, and 2.2% in the lumbar spine, femoral neck (FN), total hip (TH), and distal third of the nondominant radius (R33%), respectively. There was a significant correlation between BMD change 1 year after the PTX and CTX (L1-L4: r = 0.614, p < 0.0003; FN: r = 0.497, p < 0.0051; TH: r = 0.595, p < 0.0005; R33%: r = 0.364, p < 0.043) and P1NP (L1-L4: r = 0,687, p < 0,0001; FN: r = 0,533, p < 0,0024; TH: r = 0,642, p < 0,0001; R33%: r = 0,467, p < 0,0079) preoperative levels. The increase in 25(OH)D levels has no correlation with BMD increase (r = -0.135; p = 0.4816). On linear regression, a minimum preoperative CTX value of 0.331 ng/mL or P1NP of 37.9 ng/mL was associated with a minimum 4% increase in L1-L4 BMD. In TH, minimum preoperative values of 0.684 ng/mL for CTX and 76.0 ng/mL for P1NP were associated with a ≥ 4% increase in BMD. CONCLUSION: PHPT patients presented a significant correlation between preoperative levels of turnover markers and BMD improvement 1 year after PTX.


Assuntos
Densidade Óssea , Colágeno Tipo I/metabolismo , Hiperparatireoidismo Primário/metabolismo , Paratireoidectomia/reabilitação , Fragmentos de Peptídeos/metabolismo , Peptídeos/metabolismo , Pró-Colágeno/metabolismo , Idoso , Biomarcadores/sangue , Cálcio/sangue , Feminino , Humanos , Hiperparatireoidismo Primário/cirurgia , Masculino , Pessoa de Meia-Idade , Hormônio Paratireóideo/sangue , Fragmentos de Peptídeos/sangue , Período Pós-Operatório , Valor Preditivo dos Testes , Período Pré-Operatório , Pró-Colágeno/sangue , Estudos Retrospectivos , Vitamina D/sangue
6.
Eur J Med Chem ; 180: 238-252, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31310916

RESUMO

A series of novel chalcone derivatives was designed, synthesized and evaluated as multifunctional agents for the treatment of AD. Among of these synthesized compounds, compound TM-2 was a selective BuChE inhibitor (IC50 = 2.6 µM) and selective MAO-B inhibitor (IC50 = 5.3 µM), which were supported by docking study. Compound TM-2 also showed good antioxidant activity, and was a selective metal chelator, as well as a neuroprotectant. Moreover, compound TM-2 could significantly inhibit self-induced and Cu2+-induced Aß1-42 aggregation with 70.2% and 80.7% inhibition rate, respectively, and could disaggregate Cu2+-induced Aß1-42 aggregation (73.5%), the further TEM images observed provided rational explanation. Besides, compound TM-2 displayed good PAMPA-BBB permeability and conformed to the Lipinski's rule of five. Further, compound TM-2 presented precognitive effect on scopolamine-induced memory impairment in vivo assay. Therefore, compound TM-2 might be a promising multifunctional hit compound for the treatment of AD, and the further structure optimization are in progress.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Chalcona/farmacologia , Inibidores da Colinesterase/farmacologia , Desenho de Drogas , Inibidores da Monoaminoxidase/farmacologia , Fármacos Neuroprotetores/farmacologia , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/antagonistas & inibidores , Peptídeos beta-Amiloides/metabolismo , Animais , Butirilcolinesterase/metabolismo , Chalcona/síntese química , Chalcona/química , Inibidores da Colinesterase/síntese química , Inibidores da Colinesterase/química , Enguias , Cavalos , Humanos , Monoaminoxidase/metabolismo , Inibidores da Monoaminoxidase/síntese química , Inibidores da Monoaminoxidase/química , Fármacos Neuroprotetores/síntese química , Fármacos Neuroprotetores/química , Fragmentos de Peptídeos/antagonistas & inibidores , Fragmentos de Peptídeos/metabolismo , Agregados Proteicos/efeitos dos fármacos
7.
Chem Commun (Camb) ; 55(59): 8595-8598, 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31276123

RESUMO

The amino acid sequence plays an essential role in amyloid formation. Here, using the central core recognition module of the Aß peptide and its reverse sequence, we show that although both peptides assemble into ß-sheets, their morphologies, kinetics and cell toxicities display marked differences. In addition, the native peptide, but not the reverse one, shows notable affinity towards bilayer lipid model membranes that modulates the aggregation pathways to stabilize the oligomeric intermediate states and function as the toxic agent responsible for neuronal dysfunction.


Assuntos
Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/metabolismo , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Sequência de Aminoácidos , Peptídeos beta-Amiloides/toxicidade , Animais , Linhagem Celular Tumoral , Colesterol/química , Humanos , Cinética , Bicamadas Lipídicas/química , Bicamadas Lipídicas/metabolismo , Fragmentos de Peptídeos/toxicidade , Fosfatidilcolinas/química , Conformação Proteica em Folha beta , Multimerização Proteica , Ratos , Esfingomielinas/química
8.
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue ; 31(6): 680-683, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31315722

RESUMO

OBJECTIVE: To explore the correlation between major inflammatory factors and septic shock in intensive care unit (ICU) patients, and to provide a basis for the diagnosis and treatment of septic shock. METHODS: The patients admitted to ICU of the Third People's Hospital of Datong from March 2017 to August 2018 were selected as the research objects. According to the diagnostic criteria of septic shock, the patients were divided into septic shock group and non-septic group. The basic information and inflammatory factors levels of the two groups, including age, gender, body mass index (BMI), course of disease, acute physiology and chronic health evaluation II (APACHE II), infection site and pathogenic; and C-reactive protein (CRP), procalcitonin (PCT), neutrophil lymphocyte ratio (NLR), N-terminal pro-B-type natriuretic peptide (NT-proBNP), tumor necrosis factor-α (TNF-α), γ-interferon (IFN-γ), interleukins (IL-1ß, IL-2, IL-6, IL-8) at 8 hours after diagnosis, were compared. Logistic regression was used to analyze the influencing factors of septic shock in ICU patients. RESULTS: A total of 154 ICU patients were selected, of whom 74 had septic shock. The APACHE II score of septic shock group was significantly higher than that of non-sepsis group (23.42±3.64 vs. 15.67±2.26, P < 0.05). There was no significant difference in other baseline data between the two groups. The levels of CRP, NT-proBNP, TNF-α, IFN-γ, PCT, IL-6, IL-8 in the septic shock group were significantly higher than those in the non-septic group [CRP (mg/L): 164.3±22.6 vs. 52.3±16.2, NT-proBNP (ng/L): 426.3±288.9 vs. 167.3±80.6, TNF-α (ng/L): 193.4±39.3 vs. 88.1±20.3, IFN-γ (ng/L): 133.3±52.0 vs. 97.0±56.1, PCT (ng/L): 27.6±10.2 vs. 7.3±4.1, IL-6 (ng/L): 83.0±17.6 vs. 20.9±6.4, IL-8 (ng/L): 445.8±34.0 vs. 84.0±25.7, all P < 0.05]. It was shown by Logistic regression analysis that CRP, NT-proBNP, TNF-α, PCT, IL-6 were independent risk factors for septic shock [CRP: odds ratio (OR) = 1.662, 95% confidence interval (95%CI) = 1.132-2.567; NT-proBNP: OR = 14.688, 95%CI = 3.580-20.238; TNF-α: OR = 1.093, 95%CI = 1.043-1.343; PCT: OR = 6.378, 95%CI = 4.556-12.243; IL-6: OR = 9.641, 95%CI = 2.242-13.786; all P < 0.05]. CONCLUSIONS: The levels of inflammatory factors CRP, NT-proBNP, TNF-α, PCT and IL-6 were significantly increased, which were important factors for early diagnosis of septic shock.


Assuntos
Choque Séptico/diagnóstico , Choque Séptico/metabolismo , APACHE , Proteína C-Reativa/metabolismo , Feminino , Humanos , Unidades de Terapia Intensiva , Interleucina-6/metabolismo , Masculino , Peptídeo Natriurético Encefálico/metabolismo , Fragmentos de Peptídeos/metabolismo , Pró-Calcitonina/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
9.
Food Chem ; 299: 125051, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31284245

RESUMO

This study aims to exploit the molecular and cellular mechanisms concerning the functionality of dietary polyphenols (catechin, procyanidin B3, procyanidin C2, epigallocatechin and epigallocatechin gallate) in a nutritional context to prevent Celiac Disease (CD). In that sense, the interaction between the main CD bioactive peptide (32-mer peptide) and some polyphenols was fully characterized at the intestinal level under near physiological conditions by means of different spectroscopic techniques and dynamic simulations. Accordingly, it is proposed that the primarily polyphenol-binding sites on the 32-mer peptide correspond to leucine, tyrosine and phenylalanine containing domains being this interaction entropy-driven. Although procyanidin B3 and trimer C2 had a similar low-affinity constant at 310 K, both procyanidins were able to reduce the 32-mer peptide apical-to-basolateral translocation in in vitro simulated intestinal epithelial barrier thus prospecting the occurrence of additional and still unexplored regulatory mechanisms by which dietary polyphenols might modulate the transepithelial transport of CD bioactive peptides.


Assuntos
Alimentos , Glutens/química , Fragmentos de Peptídeos/química , Polifenóis/química , Análise Espectral , Glutens/metabolismo , Mucosa Intestinal/metabolismo , Fragmentos de Peptídeos/metabolismo , Ligação Proteica , Transporte Proteico
10.
Life Sci ; 231: 116554, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31194992

RESUMO

AIMS: Several adipokines have been proven to improve the therapeutic efficacy of mesenchymal stromal cells (MSCs) when used to treat ischemic heart disease. Asprosin (ASP) is a newly-discovered adipokine. ASP might also predict the severity of coronary pathology. We investigated the role of ASP on MSCs and the effects of ASP-pretreated MSCs on myocardial infarction (MI). MAIN METHODS: MSCs were labelled with a lentivirus carrying green fluorescent protein (GFP). For in vivo study, after pretreatment with vehicle or ASP, MSCs were injected into infarcted hearts. Cardiac function and fibrosis were then evaluated 4 weeks after the induction of MI and survival of MSCs evaluated after 1 week. MSCs proliferation and migration were investigated after ASP treatment in vitro. MSCs apoptosis induced by hydrogen peroxide (H2O2) was assessed using flow cytometry. KEY FINDINGS: Compared to vehicle-pretreated MSCs, ASP-pretreated MSCs significantly improved the left ventricular ejection fraction (LVEF), and inhibited myocardial fibrosis 4 weeks after MI. ASP pretreatment may have promoted homing of transplanted MSCs. In vitro results showed that ASP had no significant effect on MSC proliferation and migration, but protected these cells from H2O2-induced apoptosis. Among 21 molecules associated with antioxidation and cell death, the antioxidant enzyme SOD2 was significantly upregulated by ASP. Furthermore, ASP treatment inhibited H2O2-induced ROS generation and apoptosis via the activated ERK1/2-SOD2 pathway. SIGNIFICANCE: This is the first evidence that ASP can regulate MSCs function and enhance MSCs therapy for ischemic heart disease. Furthermore, we demonstrate that ASP protects MSCs from oxidative stress-induced apoptosis via the ERK1/2-SOD2 pathway.


Assuntos
Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Células-Tronco Mesenquimais/efeitos dos fármacos , Proteínas dos Microfilamentos/metabolismo , Infarto do Miocárdio/terapia , Fragmentos de Peptídeos/metabolismo , Hormônios Peptídicos/metabolismo , Superóxido Dismutase/metabolismo , Animais , Apoptose/fisiologia , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Coração/fisiopatologia , Peróxido de Hidrogênio/farmacologia , Masculino , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/patologia , Camundongos , Camundongos Endogâmicos C57BL , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Isquemia Miocárdica/metabolismo , Isquemia Miocárdica/patologia , Espécies Reativas de Oxigênio/metabolismo , Função Ventricular Esquerda
11.
Appl Microbiol Biotechnol ; 103(15): 6169-6186, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31165225

RESUMO

Ulcerative colitis (UC) is a chronic relapsing disease. Treatment of UC would benefit from specific targeting of therapeutics to the intestine. Previous studies have demonstrated that bovine lactoferricin and lactoferrampin have bactericidal, anti-inflammatory, and immunomodulatory effects. Here, we investigated whether oral administration of a bovine lactoferricin-lactoferrampin (LFCA)-encoding Lactococcus lactis (LL-LFCA) strain could alleviate experimental colitis. LFCA derived from LL-LFCA inhibited the growth of Escherichia coli and Staphylococcus aureus in vitro. In mice, administration of LL-LFCA decreased the disease activity index and attenuated dextran sulfate sodium (DSS)-induced body weight loss and colon shortening. LL-LFCA treatment also ameliorated DSS-induced colon damage, inhibited inflammatory cell infiltration, significantly decreased myeloperoxidase activity, and ameliorated DSS-induced disruption of intestinal permeability and tight junctions. In addition, 16S rDNA sequencing showed that LL-LFCA reversed DSS-induced gut dysbiosis. The production of proinflammatory mediators in serum and the colon was also reduced by administration of LL-LFCA. In vitro, LFCA derived from LL-LFCA decreased the messenger RNA expression of proinflammatory factors. The underlying mechanisms may involve inhibition of the nuclear factor kappa B (NF-κB) pathway. The results demonstrate that LL-LFCA ameliorates DSS-induced intestinal injury in mice, suggesting that LL-LFCA might be an effective drug for the treatment of inflammatory bowel diseases.


Assuntos
Antibacterianos/metabolismo , Colite/patologia , Colite/terapia , Lactococcus lactis/metabolismo , Lactoferrina/metabolismo , Fragmentos de Peptídeos/metabolismo , Proteínas Recombinantes/metabolismo , Animais , Colite/induzido quimicamente , Modelos Animais de Doenças , Disbiose/terapia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Microbioma Gastrointestinal/efeitos dos fármacos , Lactococcus lactis/genética , Lactococcus lactis/crescimento & desenvolvimento , Lactoferrina/genética , Camundongos , Fragmentos de Peptídeos/genética , Proteínas Recombinantes/genética , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Resultado do Tratamento
12.
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
13.
Eur J Med Chem ; 177: 414-424, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31158754

RESUMO

Due to the role of butyrylcholinesterase (BChE) in acetylcholine hydrolysis in the late stages of the Alzheimer's disease (AD), inhibitors of butyrylcholinesterase (BChE) have been recently envisaged, besides acetylcholinesterase (AChE) inhibitors, as candidates for treating mild-to-moderate AD. Herein, synthesis and AChE/BChE inhibition activity of some twenty derivatives of 1,2,3,4,5,6-hexahydroazepino[4,3-b]indole (HHAI) is reported. Most of the newly synthesized HHAI derivatives achieved the inhibition of both ChE isoforms with IC50s in the micromolar range, with a structure-dependent selectivity toward BChE. Apparently, molecular volume and lipophilicity do increase selectivity toward BChE, and indeed the N2-(4-phenylbutyl) HHAI derivative 15d, which behaves as a mixed-type inhibitor, resulted the most potent (IC50 0.17 µM) and selective (>100-fold) inhibitor toward either horse serum and human BChE. Moreover, 15d inhibited in vitro self-induced aggregation of neurotoxic amyloid-ß (Aß) peptide and displayed neuroprotective effects in neuroblastoma SH-SY5Y cell line, significantly recovering (P < 0.001) cell viability when impaired by Aß1-42 and hydrogen peroxide insults. Overall, this study highlighted HHAI as useful and versatile scaffold for developing new small molecules targeting some enzymes and biochemical pathways involved in the pathogenesis of AD.


Assuntos
Azepinas/farmacologia , Inibidores da Colinesterase/farmacologia , Indóis/farmacologia , Fármacos Neuroprotetores/farmacologia , Peptídeos beta-Amiloides/metabolismo , Azepinas/síntese química , Azepinas/química , Azepinas/metabolismo , Butirilcolinesterase/química , Butirilcolinesterase/metabolismo , Domínio Catalítico , Linhagem Celular Tumoral , Inibidores da Colinesterase/síntese química , Inibidores da Colinesterase/química , Inibidores da Colinesterase/metabolismo , Relação Dose-Resposta a Droga , Desenho de Drogas , Depuradores de Radicais Livres/síntese química , Depuradores de Radicais Livres/química , Depuradores de Radicais Livres/metabolismo , Depuradores de Radicais Livres/farmacologia , Humanos , Indóis/síntese química , Indóis/química , Indóis/metabolismo , Simulação de Acoplamento Molecular , Estrutura Molecular , Fármacos Neuroprotetores/síntese química , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/metabolismo , Fragmentos de Peptídeos/metabolismo , Ligação Proteica/efeitos dos fármacos , Multimerização Proteica/efeitos dos fármacos , Relação Estrutura-Atividade
14.
Artif Cells Nanomed Biotechnol ; 47(1): 2213-2220, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31159590

RESUMO

Excessive generation and accumulation of amyloid-ß (Aß) fragments by familial mutations of amyloid precursor protein (APP) and presenilin 1 (PS1) play a key role in causing oxidative stress, mitochondrial abnormalities and neuronal apoptosis in Alzheimer's disease (AD). Anagliptin, a novel DPP-4 inhibitor, is a clinical drug for the management of type II diabetes approved for use in 2012. Little on the pharmacological function of anagliptin against Aß-induced cytotoxicity in neuronal cells is known. Here, we examined the protective capacities of anagliptin against cytotoxicity in N2a neuronal cells overexpressing APP Swedish mutant and PS1 exon 9 deletion mutant (N2a/Swe.D9). Our results demonstrate that anagliptin reduced the production of ROS and the expression of NADPH oxidase 4 (NOX-4) in N2a/Swe.D9 cells. We also reported that anagliptin activates the antioxidant system by increasing the level of reduced glutathione (GSH) and glutathione peroxidase (GPx) activity. Notably, anagliptin is able to improve mitochondrial function by elevating mitochondrial membrane potential (MMP) and adenosine triphosphate (ATP) production. Additionally, our results demonstrate that anagliptin decreased the vulnerability of cells to hydrogen peroxide (H2O2)-induced secondary insult by increasing cell viability and reducing the secretion of lactate dehydrogenase (LDH) and high mobility group box 1 protein (HMGB-1). Importantly, we found that treatment with anagliptin suppressed the mitochondrial-dependent apoptosis pathway by preventing the translocation of cytochrome C, reducing cleavage of caspase-3, and the inhibiting expression of Bax. These results implicate that anagliptin may have potential as a therapeutic agent for AD treatment.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Apoptose/efeitos dos fármacos , Citoproteção/efeitos dos fármacos , Neurônios/citologia , Neurônios/efeitos dos fármacos , Fragmentos de Peptídeos/metabolismo , Pirimidinas/farmacologia , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Humanos , Neurônios/metabolismo
15.
Life Sci ; 231: 116537, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31176774

RESUMO

AIMS: Renal dysfunction has been reported in individuals with Down syndrome (DS); however, the causes and mechanisms involved remain unknown. Here, we present a proposal for how the triplication of the amyloid beta precursor protein (APP) and, mainly the amyloid ß peptide 1-42 (Aß42) can favor the development of renal abnormalities in DS. We evaluated the effects of vitamin D3 (VD3) supplementation on morphofunctional aspects and the repercussions on the presence and localization of Aß42, methylenetetrahydrofolate reductase (MTHFR), caspase-3 p12, and P-glycoprotein (Pgp) in the renal tissue of DS mouse model. MAIN METHODS: Twenty female mice (14-week-old) belonging to the B6EiC3Sn-Rb(12.Ts171665Dn)2Cje/CjeDnJ lineage were divided into four experimental groups (n = 5/group): common diet; trisomy (Ts) and wild-type (Wt); and high doses VD3, Ts(VD3), and Wt(VD3). All the groups were treated for 10 weeks. At 24 weeks, the protocol experimental was interrupted. The kidney was weighed, collected, and processed for immunochemical analysis for Aß42, Caspase-3 p12, MTHFR, and Pgp proteins. All data were analyzed statistically. KEY FINDINGS: Our results showed that VD3 promoted an increase in caspase-3 p12, MTHFR, and Pgp, and consequently contributed to reduced Aß42 in the renal tissue of a mouse model of DS. Furthermore, VD3 treatment affected the plasma creatinine and urea levels and contributed to the attenuation of the dilation of Bowman's space observed in trisomic mice. SIGNIFICANCE: Finally, the results showed that VD3 may activate specific mechanisms involved in reduced Aß42 and tissue repair in the kidneys of a mouse model for Down syndrome.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Colecalciferol/farmacologia , Síndrome de Down/tratamento farmacológico , Síndrome de Down/metabolismo , Rim/efeitos dos fármacos , Fragmentos de Peptídeos/metabolismo , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/fisiologia , Animais , Caspase 3/metabolismo , Suplementos Nutricionais , Modelos Animais de Doenças , Síndrome de Down/patologia , Feminino , Rim/metabolismo , Rim/patologia , Metilenotetra-Hidrofolato Redutase (NADPH2)/metabolismo , Camundongos , Camundongos Endogâmicos BALB C
16.
Neuron ; 103(2): 242-249.e4, 2019 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-31153646

RESUMO

For thirsty animals, fluid intake provides both satiation and pleasure of drinking. How the brain processes these factors is currently unknown. Here, we identified neural circuits underlying thirst satiation and examined their contribution to reward signals. We show that thirst-driving neurons receive temporally distinct satiation signals by liquid-gulping-induced oropharyngeal stimuli and gut osmolality sensing. We demonstrate that individual thirst satiation signals are mediated by anatomically distinct inhibitory neural circuits in the lamina terminalis. Moreover, we used an ultrafast dopamine (DA) sensor to examine whether thirst satiation itself stimulates the reward-related circuits. Interestingly, spontaneous drinking behavior but not thirst drive reduction triggered DA release. Importantly, chemogenetic stimulation of thirst satiation neurons did not activate DA neurons under water-restricted conditions. Together, this study dissected the thirst satiation circuit, the activity of which is functionally separable from reward-related brain activity.


Assuntos
Neurônios GABAérgicos/fisiologia , Rede Nervosa/fisiologia , Vias Neurais/fisiologia , Saciação/fisiologia , Estômago/inervação , Órgão Subfornical/citologia , Animais , Cálcio/metabolismo , Dopamina/metabolismo , Ingestão de Líquidos/fisiologia , Feminino , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Óxido Nítrico Sintase Tipo I/genética , Óxido Nítrico Sintase Tipo I/metabolismo , Optogenética , Concentração Osmolar , Fragmentos de Peptídeos/metabolismo , Estimulação Física
17.
Int J Mol Sci ; 20(11)2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31181592

RESUMO

Platelet interaction with collagens, via von Willebrand factor, is a potent trigger of shear-dependent thrombus formation mediated by subsequent engagement of the signaling collagen receptor glycoprotein (GP)VI, enforced by integrin α2ß1. Protein tyrosine kinase Syk is central in the GPVI-induced signaling pathway, leading to elevated cytosolic Ca2+. We aimed to determine the Syk-mediated thrombogenic activity of several collagen peptides and (fibrillar) type I and III collagens. High-shear perfusion of blood over microspots of these substances resulted in thrombus formation, which was assessed by eight parameters and was indicative of platelet adhesion, activation, aggregation, and contraction, which were affected by the Syk inhibitor PRT-060318. In platelet suspensions, only collagen peptides containing the consensus GPVI-activating sequence (GPO)n and Horm-type collagen evoked Syk-dependent Ca2+ rises. In whole blood under flow, Syk inhibition suppressed platelet activation and aggregation parameters for the collagen peptides with or without a (GPO)n sequence and for all of the collagens. Prediction models based on a regression analysis indicated a mixed role of GPVI in thrombus formation on fibrillar collagens, which was abolished by Syk inhibition. Together, these findings indicate that GPVI-dependent signaling through Syk supports platelet activation in thrombus formation on collagen-like structures regardless of the presence of a (GPO)n sequence.


Assuntos
Plaquetas/metabolismo , Colágeno/metabolismo , Glicoproteínas da Membrana de Plaquetas/metabolismo , Quinase Syk/metabolismo , Trombose/metabolismo , Plaquetas/efeitos dos fármacos , Plaquetas/fisiologia , Células Cultivadas , Colágeno/química , Cicloexilaminas/farmacologia , Humanos , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Agregação Plaquetária , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/farmacologia , Quinase Syk/antagonistas & inibidores
18.
Inorg Chem ; 58(11): 7488-7498, 2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31083932

RESUMO

It was shown that His3 of human copper transporter 1 (hCtr1) prompts the ATCUN-like Cu(II) coordination for model peptides of the hCtr1 N-terminus. Its high Cu(II) affinity is a potential driving force for the transfer of Cu(II) from extracellular Cu(II) carriers to hCtr1. Having a sequence similar to that of hCtr1, hCtr2 has been proposed as another human copper transporter. However, the N-terminal domain of hCtr2 is much shorter than that of hCtr1, with different copper binding motifs at its N-terminus. Employing a model peptide of the hCtr2 N-terminus, MAMHF-am, we demonstrated that His4 provides a unique pattern of Cu(II) complexes, involving Met sulfurs in their Cu(II) coordination sphere. The affinity of Cu(II) for MAMHF-am is a few orders of magnitude lower than that reported for the hCtr1 model peptides at the extracellular pH of 7.4, suggesting a maximal complementary role of Cu(II) binding to hCtr2 in the import of copper from the extracellular space to the cytoplasm. On the other hand, the ability of the hCtr2 model peptide to capture Cu(II) from amino acids and short peptides (potential degradation products of proteins) at pH 5.0 and the known predominant lysosomal localization of hCtr2 support an important potential role of the Cu(II)-hCtr2 interaction in the recovery of copper from lysosomes.


Assuntos
Proteínas de Transporte de Cátions/química , Cobre/metabolismo , Espaço Extracelular/química , Lisossomos/química , Fragmentos de Peptídeos/metabolismo , Sequência de Aminoácidos , Espaço Extracelular/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Lisossomos/metabolismo , Modelos Moleculares , Fragmentos de Peptídeos/química , Ligação Proteica , Conformação Proteica
19.
Food Funct ; 10(5): 2997-3007, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31086895

RESUMO

(-)-Epigallocatechin-3-gallate (EGCG), a major phenolic constituent of tea, has been shown to have biological activity within inflammatory pathways involved with food allergies and intolerances. Proposed mechanisms for this effect include sequestration and structural modification of immunostimulatory proteins as a result of interactions with EGCG. The present study employs biophysical techniques including dynamic light scattering, circular dichroism and nuclear magnetic resonance to elucidate the likely mechanism(s) by which EGCG interacts with α2-gliadin (57-89) (α2g), an immunodominant peptide in celiac disease pathogenesis. We demonstrate that EGCG interacts with α2g in a multi-phase reaction driven by non-specific binding, resulting in the formation of polydisperse EGCG/α2g complexes which induce changes in peptide structure. We also show that these interactions occur at a range of pH levels associated with digestion, including pH 2.0, 6.8 and 7.5. Based on previous reports of binding specificity of enzymes and antigen presenting cells in celiac disease pathogenesis, our results provide foundational support for EGCG to prevent recognition of immunostimulatory gliadin epitopes by the body and thus prevent the inflammatory and autoimmune response associated with celiac disease.


Assuntos
Catequina/análogos & derivados , Doença Celíaca/metabolismo , Gliadina/química , Fragmentos de Peptídeos/química , Extratos Vegetais/química , Camellia sinensis/química , Camellia sinensis/metabolismo , Catequina/química , Catequina/metabolismo , Dicroísmo Circular , Humanos , Concentração de Íons de Hidrogênio , Fragmentos de Peptídeos/metabolismo , Extratos Vegetais/metabolismo
20.
Nat Commun ; 10(1): 2240, 2019 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-31110178

RESUMO

The beta-site APP cleaving enzyme 1 (BACE1) is known primarily for its initial cleavage of the amyloid precursor protein (APP), which ultimately leads to the generation of Aß peptides. Here, we provide evidence that altered BACE1 levels and activity impact the degradation of Aß40 and Aß42 into a common Aß34 intermediate. Using human cerebrospinal fluid (CSF) samples from the Amsterdam Dementia Cohort, we show that Aß34 is elevated in individuals with mild cognitive impairment who later progressed to dementia. Furthermore, Aß34 levels correlate with the overall Aß clearance rates in amyloid positive individuals. Using CSF samples from the PREVENT-AD cohort (cognitively normal individuals at risk for Alzheimer's disease), we further demonstrate that the Aß34/Aß42 ratio, representing Aß degradation and cortical deposition, associates with pre-clinical markers of neurodegeneration. We propose that Aß34 represents a marker of amyloid clearance and may be helpful for the characterization of Aß turnover in clinical samples.


Assuntos
Doença de Alzheimer/patologia , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Ácido Aspártico Endopeptidases/metabolismo , Disfunção Cognitiva/patologia , Fragmentos de Peptídeos/metabolismo , Idoso , Doença de Alzheimer/líquido cefalorraquidiano , Secretases da Proteína Precursora do Amiloide/genética , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Animais , Ácido Aspártico Endopeptidases/genética , Biomarcadores/líquido cefalorraquidiano , Biomarcadores/metabolismo , Encéfalo/patologia , Linhagem Celular Tumoral , Disfunção Cognitiva/líquido cefalorraquidiano , Estudos de Coortes , Progressão da Doença , Feminino , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Pessoa de Meia-Idade , Fragmentos de Peptídeos/líquido cefalorraquidiano , Proteólise , Ratos , Ratos Sprague-Dawley
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