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1.
J Phys Chem B ; 128(22): 5387-5396, 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38787393

RESUMO

Q11 peptide nanofibers are used as a biomaterial for applications such as antigen presentation and tissue engineering, yet detailed knowledge of molecular-level structure has not been reported. The Q11 peptide sequence was designed using heuristics-based patterning of hydrophobic and polar amino acids with oppositely charged amino acids placed at opposite ends of the sequence to promote antiparallel ß-sheet formation. In this work, we employed solid-state nuclear magnetic resonance spectroscopy (NMR) to evaluate whether the molecular organization within Q11 self-assembled peptide nanofibers is consistent with the expectations of the peptide designers. We discovered that Q11 forms a distribution of molecular structures. NMR data from two-dimensional (2D) 13C-13C dipolar-assisted rotational resonance indicate that the K3 and E9 residues between Q11 ß-strands are spatially proximate (within ∼0.6 nm). Frequency-selective rotational echo double resonance (fsREDOR) on K3 Nζ and E9 Cδ-labeled sites showed that approximately 9% of the sites are close enough for salt bridge formation to occur. Surprisingly, dipolar recoupling measurements revealed that Q11 peptides do not assemble into antiparallel ß-sheets as expected, and structural analysis using Fourier-transform infrared spectroscopy and 2D NMR alone can be misleading. 13C PITHIRDS-CT dipolar recoupling measurements showed that the most abundant structure consists of parallel ß-sheets, in contrast to the expected antiparallel ß-sheet structure. Structural heterogeneity was detected from 15N{13C} REDOR measurements, with approximately 22% of ß-strands having antiparallel nearest neighbors. We cannot propose a complete structural model of Q11 nanofibers because of the complexity involved when examining structurally heterogeneous samples using NMR. Altogether, our results show that while heuristics-based patterning is effective in promoting ß-sheet formation, designing a peptide sequence to form a targeted ß-strand arrangement remains challenging.


Assuntos
Nanofibras , Peptídeos , Conformação Proteica em Folha beta , Nanofibras/química , Peptídeos/química , Ressonância Magnética Nuclear Biomolecular , Sequência de Aminoácidos
2.
Angew Chem Int Ed Engl ; 62(51): e202314531, 2023 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-37931093

RESUMO

Self-assembly of proteinaceous biomolecules into functional materials with ordered structures that span length scales is common in nature yet remains a challenge with designer peptides under ambient conditions. This report demonstrates how charged side-chain chemistry affects the hierarchical co-assembly of a family of charge-complementary ß-sheet-forming peptide pairs known as CATCH(X+/Y-) at physiologic pH and ionic strength in water. In a concentration-dependent manner, the CATCH(6K+) (Ac-KQKFKFKFKQK-Am) and CATCH(6D-) (Ac-DQDFDFDFDQD-Am) pair formed either ß-sheet-rich microspheres or ß-sheet-rich gels with a micron-scale plate-like morphology, which were not observed with other CATCH(X+/Y-) pairs. This hierarchical order was disrupted by replacing D with E, which increased fibril twisting. Replacing K with R, or mutating the N- and C-terminal amino acids in CATCH(6K+) and CATCH(6D-) to Qs, increased observed co-assembly kinetics, which also disrupted hierarchical order. Due to the ambient assembly conditions, active CATCH(6K+)-green fluorescent protein fusions could be incorporated into the ß-sheet plates and microspheres formed by the CATCH(6K+/6D-) pair, demonstrating the potential to endow functionality.


Assuntos
Peptídeos , Conformação Proteica em Folha beta , Peptídeos/química , Géis
3.
Br Poult Sci ; 64(5): 625-633, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37466364

RESUMO

1. A study was conducted to evaluate the effects of dietary cholecalciferol (vitamin D3) and 25-hydroxycholecalciferol (25-OH-D3) supplementation on the reproductive performance, egg quality, eggshell ultrastructure, serum hormone level and antioxidant capacity, intestinal morphology and tibia quality of breeder geese during the laying period.2. The trial was designed as a 3 × 3 factorial arrangement with three levels (300, 400 and 500 IU/kg) of vitamin D3 supplementation and three levels (25, 50 and 75 µg/kg) of 25-OH-D3 supplementation in a 10-wk feeding trial.3. The results showed that the combined supplementation of 400 IU/kg vitamin D3 and 50 µg/kg 25-OH-D3 had a better feed conversion ratio and a higher egg laying rate than the other groups. Vitamin D3 supplementation significantly increased the rate of qualified eggs for hatching, eggshell strength and thickness, serum testosterone and progesterone levels, serum total superoxide dismutase and glutathione peroxidase activities, tibia ash content and bone mineral density (P < 0.05). Dietary 25-OH-D3 supplementation significantly increased serum glutathione peroxidase activity and duodenal villus height and villus height-to-crypt-depth ratio (P < 0.05). The geese receiving 500 IU/kg vitamin D3 and 75 µg/kg 25-OH-D3 had the highest tibia calcium and phosphorous content among all groups (P < 0.05).4. Feeding 400 IU/kg vitamin D3 plus 50 µg/kg 25-OH-D3 gave optimal effects on feed conversion ratio and egg laying rate. This combination could be a nutritional strategy for increasing the laying rate, eggshell quality, serum hormone levels and serum antioxidant function regardless of 25-OH-D3 supplementation. Supplementation of 50 µg/kg 25-OH-D3 could be a recommended dose for improving the serum antioxidant capacity and intestinal morphology regardless of vitamin D3 supplementation.


Assuntos
Calcifediol , Colecalciferol , Animais , Ração Animal/análise , Antioxidantes , Galinhas , Colecalciferol/farmacologia , Dieta/veterinária , Suplementos Nutricionais , Gansos , Glutationa Peroxidase , Hormônios , Óvulo , Tíbia
4.
Zhonghua Yan Ke Za Zhi ; 59(7): 542-549, 2023 Jul 11.
Artigo em Chinês | MEDLINE | ID: mdl-37408425

RESUMO

Objective: To investigate the clinical effects of the bow-tie adjustable suture technique in managing overcorrection in patients with intermittent exotropia after surgery. Methods: This was a retrospective case series study. Clinical data were collected from children with intermittent exotropia who underwent strabismus correction surgery, including the bow-tie adjustable suture technique and conventional techniques, at the Department of Strabismus and Pediatric Ophthalmology, Shanxi Eye Hospital, from January 2020 to September 2021. Children with postoperative esodeviation≥15 prism diopters (PD) within the first 6 days were treated differently based on the surgical technique and their individual conditions, including suture adjustment and conservative treatment. The overcorrection rate and its changes among different surgical groups, the recovery of ocular alignment and binocular visual function after different treatment methods in children with overcorrection on the sixth postoperative day, and the postoperative complications in different surgical groups were observed. Statistical analysis was performed using independent samples t-test, Wilcoxon rank-sum test, repeated-measures analysis of variance, Bonferroni test, chi-square test, or Fisher's exact probability test, as appropriate. Results: A total of 643 children who underwent intermittent exotropia correction surgery were included in the study. Among them, 325 children underwent the bow-tie adjustable suture technique, with 185 males and 140 females, and the mean age was (9.50±2.69) years. The remaining 318 children underwent conventional techniques, with 176 males and 142 females, and the mean age was (9.90±2.67) years. There were no statistically significant differences in age and gender distribution between the two surgical groups (all P>0.05). On the first postoperative day, among children who underwent the bow-tie adjustable suture technique, 40 had an esodeviation of≥10 PD, resulting in an overcorrection rate of 12.3% (40/325), while among children who underwent conventional techniques, 32 had an esodeviation of≥10 PD, resulting in an overcorrection rate of 10.1% (32/318). On the sixth postoperative day, these rates decreased to 5.5% (18/325) and 3.1% (10/318) in the two groups, respectively. At 1, 6, and 12 months postoperatively, the overcorrection rate in children who underwent the bow-tie adjustable suture technique was 0, while in children who underwent conventional techniques, the overcorrection rate did not show a significant decrease compared to before surgery. The differences between the two surgical groups were statistically significant (all P<0.05). On the sixth postoperative day, among children with an esodeviation of≥15 PD, 13 underwent suture adjustment and 7 received conservative treatment. The results of repeated-measures analysis of variance showed statistically significant differences in near and distance esodeviation angles among children who received different treatment methods (F=145.20, 106.87, both P<0.001), as well as statistically significant differences in near and distance esodeviation angles at different time points within each group of children (F=81.67, 35.09, both P<0.001). There were also significant differences in the trends of change in near and distance esodeviation angles at different time points among children who received different treatment methods (F=79.90, 36.73, both P<0.001). Further pairwise comparisons showed significant differences in near and distance esodeviation angles between the sixth postoperative day and 1, 6, and 12 months postoperatively in children who underwent suture adjustment (all P<0.05), while no statistically significant differences were observed in children who received conservative treatment (all P>0.05). At 12 months postoperatively, among the 13 children who underwent suture adjustment, 12 achieved stereopsis, while among the 7 children who received conservative treatment, all became stereo-blind after removing the prismatic correction. No serious complications occurred in any of the children postoperatively. Conclusion: The proportion of children with intermittent exotropia who achieved orthotropic alignment one year after surgery was relatively low among those who had an overcorrection of≥15 PD on the sixth postoperative day. The bow-tie adjustable suture technique is a simple and effective approach for managing overcorrection in patients with intermittent exotropia. Adjusting the sutures on the sixth postoperative day can reduce the overcorrection rate and is considered a safe and effective method.


Assuntos
Esotropia , Exotropia , Estrabismo , Masculino , Criança , Feminino , Humanos , Exotropia/cirurgia , Resultado do Tratamento , Seguimentos , Esotropia/cirurgia , Estudos Retrospectivos , Acuidade Visual , Procedimentos Cirúrgicos Oftalmológicos/métodos , Estrabismo/cirurgia , Músculos Oculomotores/cirurgia , Visão Binocular , Técnicas de Sutura , Doença Crônica
5.
Clin Gastroenterol Hepatol ; 20(1): 173-182.e7, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34391922

RESUMO

BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide. Although biannual ultrasound surveillance with or without α-fetoprotein (AFP) testing is recommended for at-risk patients, sensitivity for early stage HCC, for which potentially curative treatments exist, is suboptimal. We conducted studies to establish the multitarget HCC blood test (mt-HBT) algorithm and cut-off values and to validate test performance in patients with chronic liver disease. METHODS: Algorithm development and clinical validation studies were conducted with participants in an international, multicenter, case-control study. Study subjects had underlying cirrhosis or chronic hepatitis B virus; HCC cases were diagnosed per the American Association for the Study of Liver Diseases criteria and controls were matched for age and liver disease etiology. Whole blood and serum were shipped to a central laboratory and processed while blinded to case/control status. An algorithm was developed for the mt-HBT, which incorporates methylation biomarkers (HOXA1, TSPYL5, and B3GALT6), AFP, and sex. RESULTS: In algorithm development, with 136 HCC cases (60% early stage) and 404 controls, the mt-HBT showed 72% sensitivity for early stage HCC at 88% specificity. Test performance was validated in an independent cohort of 156 HCC cases (50% early stage) and 245 controls, showing 88% overall sensitivity, 82% early stage sensitivity, and 87% specificity. Early stage sensitivity in clinical validation was significantly higher than AFP at 20 ng/mL or greater (40%; P < .0001) and GALAD (gender, age, Lens culinaris agglutinin-reactive AFP, AFP, and des-γ-carboxy-prothrombin score) of -0.63 or greater (71%; P = .03), although AFP and GALAD at these cut-off values had higher specificities (100% and 93%, respectively). CONCLUSIONS: The mt-HBT may significantly improve early stage HCC detection for patients undergoing HCC surveillance, a critical step to increasing curative treatment opportunities and reducing mortality. ClinicalTrials.gov number NCT03628651.


Assuntos
Carcinoma Hepatocelular , Hepatite B Crônica , Neoplasias Hepáticas , Biomarcadores , Biomarcadores Tumorais , Carcinoma Hepatocelular/patologia , Estudos de Casos e Controles , Galactosiltransferases , Testes Hematológicos , Hepatite B Crônica/complicações , Humanos , Cirrose Hepática/complicações , Neoplasias Hepáticas/patologia , Proteínas Nucleares , Precursores de Proteínas , Protrombina , Sensibilidade e Especificidade , alfa-Fetoproteínas
6.
J Phys Chem B ; 125(50): 13599-13609, 2021 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-34905370

RESUMO

Peptide coassembly, wherein at least two different peptides interact to form multicomponent nanostructures, is an attractive approach for generating functional biomaterials. Current efforts seek to design pairs of peptides, A and B, that form nanostructures (e.g., ß-sheets with ABABA-type ß-strand patterning) while resisting self-assembly (e.g., AAAAA-type or BBBBB-type ß-sheets). To confer coassembly behavior, most existing designs have been based on highly charged variants of known self-assembling peptides; like-charge repulsion limits self-assembly while opposite-charge attraction promotes coassembly. Recent analyses using solid-state NMR and coarse-grained simulations reveal that preconceived notions of structure and molecular organization are not always correct. This perspective highlights recent advances and key challenges to understanding and controlling peptide coassembly.


Assuntos
Materiais Biocompatíveis , Nanoestruturas , Espectroscopia de Ressonância Magnética , Peptídeos , Conformação Proteica em Folha beta
7.
J Phys Chem B ; 125(16): 4004-4015, 2021 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-33876641

RESUMO

Coassembling peptides offer an additional degree of freedom in the design of nanostructured biomaterials when compared to analogous self-assembling peptides. Yet, our understanding of how amino acid sequences encodes coassembled nanofiber structure is limited. Prior work on a charge-complementary pair, CATCH+ and CATCH- peptides, detected like-peptide nearest neighbors (CATCH+:CATCH+ and CATCH-:CATCH-) within coassembled ß-sheet nanofibers; these self-associated peptide pairs marked a departure from an "ideal" coassembled structure. In this work, we employ solid-state NMR, isotope-edited FTIR, and coarse-grained molecular dynamics simulations to evaluate the alignment of ß-strands within CATCH peptide nanofibers. Both experimental and computational results suggest that CATCH molecules coassemble into structurally heterogeneous nanofibers, which is consistent with our observations in another coassembling system, the King-Webb peptides. Within ß-sheet nanofibers, ß-strands were found to have nearest neighbors aligned in-register parallel, in-register antiparallel, and out-of-register. In comparison to the King-Webb peptides, CATCH nanofibers exhibit a greater degree of structural heterogeneity. By comparing the amino acid sequences of CATCH and King-Webb peptides, we can begin to unravel sequence-to-structure relationships, which may encode more precise coassembled ß-sheet nanostructures.


Assuntos
Nanofibras , Sequência de Aminoácidos , Simulação de Dinâmica Molecular , Peptídeos , Conformação Proteica em Folha beta
9.
Zhonghua Yan Ke Za Zhi ; 56(11): 853-858, 2020 Nov 11.
Artigo em Chinês | MEDLINE | ID: mdl-33152844

RESUMO

Objective: To investigate the long-term clinical efficacy and safety of the bilateral superior oblique tendon suture spacer in treatment of A-pattern strabismus with superior oblique overaction (SOOA). Methods: Retrospective case series study. Twenty-one A-pattern strabismus patients who received the quantitative bilateral superior oblique tendon suture spacer with a complete follow-up from January 2009 to August 2017 were enrolled. Among these patients, 19 were exotropic and 2 were esotropic, including 11 males and 10 females, aged (14±9) years. Patients with unilateral superior oblique overaction, Broun syndrome or Helveston syndrome were excluded. The A-pattern strabismus, objective torsion, function of the superior oblique muscle and binocular vision were examined pre-and post-operatively. Paired t-test was used for normal distribution data, Wilcoxon rank-sum test was used for non-normal distribution data, Spearman rank correlation test and simple linear regression were used to analyze the correlation between the two variables. Results: The follow-up was 12 to 109 months (mean, 26±17 months). Twenty patients showed good alignment in the primary position with a deviation angle less than 10 prism diopter (PD), and 1 patient with esotropia had an angle greater than 15 PD. All the patients had no A pattern after surgery. The average pre-and post-operative A-patterns were (23.81±9.47) PD and (0.90±3.59) PD (t=11.29, P<0.01), respectively, and the average corrected A pattern was (23.52±9.68) PD.The average pre-and post-operative torsion was 3.18°±3.26° and -4.81°±4.13° (t=8.87, P<0.01), espectively, and the average corrected torsion was 7.95°±3.88°. No patient complained of torsional diplopia after surgery. The average amount of pre-and post-operative SOOA was 3.0 (2.0) and 0.0 (1.0) in 42 eyes (Z=-5.78, P<0.01), respectively. Suture extension of the superior oblique tendon was related with the pre-operative SOOA (r=0.47, P<0.01), but was not related with the pre-operative torsion (r=0.02, P=0.88). The linear regression results was suture extension=2.71× the grade of pre-operative SOOA (t=27.93, P<0.01). Conclusions: The bilateral superior oblique tendon suture spacer can improve the A-pattern, objective torsion and SOOA, with no torsional diplopia or V pattern after the long-term follow-up. It is a safe and effective superior oblique muscle weakening procedure. (Chin J Ophthalmol, 2020, 56: 853-858).


Assuntos
Músculos Oculomotores , Estrabismo , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Músculos Oculomotores/cirurgia , Procedimentos Cirúrgicos Oftalmológicos , Estudos Retrospectivos , Estrabismo/cirurgia , Suturas , Tendões/cirurgia , Resultado do Tratamento , Visão Binocular , Adulto Jovem
10.
Front Immunol ; 11: 1547, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32849524

RESUMO

Peptide subunit vaccines increase safety by reducing the risk of off-target responses and improving the specificity of the induced adaptive immune response. The immunogenicity of most soluble peptides, however, is often insufficient to produce robust and lasting immunity. Many biomaterials and delivery vehicles have been developed for peptide antigens to improve immune response while maintaining specificity. Peptide nanoclusters (PNC) are a subunit peptide vaccine material that has shown potential to increase immunogenicity of peptide antigens. PNC are comprised only of crosslinked peptide antigen and have been synthesized from several peptide antigens as small as 8 amino acids in length. However, as with many peptide vaccine biomaterials, synthesis requires adding residues to the peptide and/or engaging amino acids within the antigen epitope covalently to form a stable material. The impact of antigen modifications made to enable biomaterial incorporation or formation is rarely investigated, since the goal of most studies is to compare the soluble antigen with biomaterial form of antigen. This study investigates PNC as a platform vaccine biomaterial to evaluate how peptide modification and biomaterial formation with different crosslinking chemistries affect epitope-specific immune cell presentation and activation. Several types of PNC were synthesized by desolvation from the model peptide epitope SIINFEKL, which is derived from the immunogenic protein ovalbumin. SIINFEKL was altered to include extra residues on each end, strategically chosen to enable multiple conjugation chemistry options for incorporation into PNC. Several crosslinking methods were used to control which functional groups were used to stabilize the PNC, as well as the reducibility of the crosslinking. These variations were evaluated for immune responses and biodistribution following in vivo immunization. All modified antigen formulations still induced comparable immune responses when incorporated into PNC compared to unmodified soluble antigen alone. However, some crosslinking methods led to a significant increase in desirable immune responses while others did not, suggesting that not all PNC were processed the same. These results help guide future peptide vaccine biomaterial design, including PNC and a wide variety of conjugated and self-assembled peptide antigen materials, to maximize and tune the desired immune response.


Assuntos
Adjuvantes Imunológicos , Antígenos/imunologia , Materiais Biocompatíveis , Vacinas de Subunidades Antigênicas/imunologia , Sequência de Aminoácidos , Animais , Antígenos/química , Materiais Biocompatíveis/química , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Epitopos/química , Epitopos/imunologia , Camundongos , Nanopartículas/química , Nanoestruturas/química , Peptídeos/química , Peptídeos/imunologia , Linfócitos T/imunologia , Linfócitos T/metabolismo , Vacinas de Subunidades Antigênicas/química
11.
Sci Adv ; 6(23): eaaz5132, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32548258

RESUMO

Iron is one of the most studied chemical elements due to its sociotechnological and planetary importance; hence, understanding its structural transition dynamics is of vital interest. By combining a short pulse optical laser and an ultrashort free electron laser pulse, we have observed the subnanosecond structural dynamics of iron from high-quality x-ray diffraction data measured at 50-ps intervals up to 2500 ps. We unequivocally identify a three-wave structure during the initial compression and a two-wave structure during the decaying shock, involving all of the known structural types of iron (α-, γ-, and ε-phase). In the final stage, negative lattice pressures are generated by the propagation of rarefaction waves, leading to the formation of expanded phases and the recovery of γ-phase. Our observations demonstrate the unique capability of measuring the atomistic evolution during the entire lattice compression and release processes at unprecedented time and strain rate.

12.
Nanoscale ; 12(7): 4506-4518, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32039428

RESUMO

Self-assembling peptides have garnered an increasing amount of interest as a functional biomaterial for medical and biotechnological applications. Recently, ß-sheet peptide designs utilizing complementary pairs of peptides composed of charged amino acids positioned to impart co-assembly behavior have expanded the portfolio of peptide aggregate structures. Structural characterization of these charge-complementary peptide co-assemblies has been limited. Thus, it is not known how the complementary peptides organize on the molecular level. Through a combination of solid-state NMR measurements and discontinuous molecular dynamics simulations, we investigate the molecular organization of King-Webb peptide nanofibers. KW+ and KW- peptides co-assemble into near stoichiometric two-component ß-sheet structures as observed by computational simulations and 13C-13C dipolar couplings. A majority of ß-strands are aligned with antiparallel nearest neighbors within the ß-sheet as previously suggested by Fourier transform infrared spectroscopy measurements. Surprisingly, however, a significant proportion of ß-strand neighbors are parallel. While charge-complementary peptides were previously assumed to organize in an ideal (AB)n pattern, dipolar recoupling measurements on isotopically diluted nanofiber samples reveal a non-negligible amount of self-associated (AA and BB) pairs. Furthermore, computational simulations predict these different structures can coexist within the same nanofiber. Our results highlight structural disorder at the molecular level in a charge-complementary peptide system with implications on co-assembling peptide designs.


Assuntos
Nanofibras/química , Peptídeos/química , Conformação Proteica em Folha beta , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Curr Org Synth ; 16(8): 1166-1173, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31984923

RESUMO

BACKGROUND: Sesamol is a widely used antioxidant for the food and pharmaceutical industries. The oxidation products of this compound may be accumulated in foods or ingested. Little is known about its effect on human health. OBJECTIVE: It is of great interest to identify the oxidation products of sesamol that may be beneficial to humans. This study was undertaken to identify the oxidation products of sesamol and investigate their antioxidant and cytotoxic activities. MATERIALS AND METHODS: Using the ferricyanide oxidation approach, four oxidation products of sesamol (2, 3, 20 & 21) have been identified. Structural elucidation of these compounds was established on the basis of their detailed NMR spectroscopic analysis, mass spectrometry and x-ray crystallography. Additionally, a formation mechanism of compound 20 was proposed based on high-resolution mass spectrometry-fragmentation method. The antioxidant activities of these compounds were determined by the DPPH, FRAP, and ABTS assays. The in vitro antiproliferative activity of these compounds was evaluated against a panel of human cancer cell lines as well as non-cancerous cells. RESULTS: Two oxidation products of sesamol were found to contain an unusual methylenedioxy ring-opening skeleton, as evidenced by spectroscopic and x-ray crystallographic data. Among all compounds, 20 displayed impressive antiproliferative activities against a panel of human cancer cell lines yet remained non-toxic to noncancerous cells. The antioxidant activities of compound 20 are significantly weaker than sesamol as determined by the DPPH, FRAP, and ABTS assays. CONCLUSION: The oxidation products of sesamol could be a valuable source of bioactive molecules. Compound 20 may be used as a potential lead molecule for cancer studies.


Assuntos
Antioxidantes/química , Benzodioxóis/química , Fenóis/química , Antineoplásicos/química , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Benzodioxóis/farmacologia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Dimerização , Ferricianetos/química , Humanos , Estrutura Molecular , Oxirredução , Fenóis/farmacologia
15.
Eur Rev Med Pharmacol Sci ; 22(18): 6133-6138, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30280801

RESUMO

OBJECTIVE: The endoplasmic reticulum (ER) -resident caspase-12 was identified as a mediator of Aß neurotoxicity. Recent evidence indicates that mitochondrial ATP-sensitive potassium (KATP) channel openers mediate their neuroprotective role by adjusting ER stress pathways, but the molecular details remain largely unknown and have been investigated. MATERIALS AND METHODS: In this study, the protein expression levels of calreticulin (CRT) and caspase-12 activation and phosphorylated p38 MAPK were observed by immunoblotting in cultured PC12 cells from different groups: treatment with Aß25-35 (group Aß25-35), treatment with diazoxide (group diazoxide), pretreatment with diazoxide and then exposure to Aß25-35 (group diazoxide + Aß25-35), pretreatment with p38 MAPK inhibitor SB 203580 and then exposure to diazoxide and Aß25-35 (group SB 203580 + diazoxide + Aß25-35), and the control (group control). RESULTS: In response to the treatment with Aß25-35 (10 µM) for 24 h, the protein expression levels of CRT and caspase-12 activation were increased and phosphorylated p38 MAPK was decreased significantly. Diazoxide reduced CRT overexpression and caspase-12 activation and increased the up-regulation of phosphorylated p38 MAPK. When SB 203580 was presented before exposure to diazoxide and Aß25-35, CRT expression was markedly suppressed, and the inhibition effect of diazoxide on caspase-12 activation was almost eliminated. CONCLUSIONS: We showed that diazoxide induced ERS-related neuroprotection mediated by p38 MAPK against Aß25-35 insults. From the clinical point of view, these results are of considerable importance for the understanding of AD pathogenesis. However, further studies are required to explore more detailed mechanisms of the observed effects.


Assuntos
Peptídeos beta-Amiloides/toxicidade , Diazóxido/farmacologia , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Neuroproteção , Fragmentos de Peptídeos/toxicidade , Proteínas Quinases p38 Ativadas por Mitógeno/fisiologia , Animais , Apoptose/efeitos dos fármacos , Caspase 12/metabolismo , Estresse do Retículo Endoplasmático/fisiologia , Células PC12 , Ratos , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores
16.
Soft Matter ; 14(44): 8986-8996, 2018 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-30375627

RESUMO

We report an unanticipated helix-to-sheet structural transformation within an assembly of SAF-p1 and SAF-p2a designer peptides. Solid-state NMR spectroscopic data support the assembled structure that was targeted by rational peptide design: an α-helical coiled-coil co-assembly of both peptides. Subsequent to assembly, however, the system converts to a ß-sheet structure that continues to exhibit nearest-neighbor interactions between the two peptide components. The structural transition occurs at pH 7.4 and exhibits strongly temperature-dependent kinetics between room temperature (weeks) and 40 °C (minutes). We further observed evidence of reversibility on the timescale of months at 4 °C. The structural conversion from the anticipated structure to an unexpected structure highlights an important aspect to the challenge of designing peptide assemblies. Furthermore, the conformational switching mechanism mediated by a prerequisite α-helical nanostructure represents a previously unknown route for ß-sheet designer peptide assembly.


Assuntos
Nanofibras/química , Peptídeos/química , Sequência de Aminoácidos , Concentração de Íons de Hidrogênio , Cinética , Modelos Moleculares , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Temperatura
17.
Eur Rev Med Pharmacol Sci ; 22(8): 2218-2225, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29762822

RESUMO

OBJECTIVE: To observe the expressions of Linc-ROR and proteins in the PI3K-Akt pathway in an ectopic lesion of adenomyosis. PATIENTS AND METHODS: The expression of Linc-ROR in the ectopic endometrium, eutopic endometrium, and normal endometrium of adenomyosis was detected by qRT-PCR. Western blot was used to detect the protein expressions of PI3K-Akt in endometriosis and lesion endometriosis. Cell counting kit-8 (CCK-8) assay was utilized to detect cell proliferative activity. After interfering or overexpressing Linc-ROR, protein expressions of the PI3K-Akt pathway were detected by Western blot. RESULTS: Linc-ROR expression in the ectopic endometrium of adenomyosis was higher than that in the eutopic endometrium and normal endometrium, and the expression level of PTEN in adenomyosis tissues was decreased, whilst expression levels of Akt, p-Akt, p-PTEN were increased. Clinical data of enrolled patients indicated that there was a relationship between Linc-ROR expression and the type and severity of dysmenorrhea of adenomyosis. However, no relationship was observed between Linc-ROR expression and age, cesarean section, uterine surgery, and menstrual cycle. Cell counting kit-8 (CCK-8) assay showed that the proliferative activity of cells was significantly decreased after knockdown of Linc-ROR in the adenomyosis cells. Western blot revealed that the expression level of PTEN increased but the expression levels of p-Akt, p-PTEN and p-PDK1 decreased. Overexpression of Linc-ROR obtained the opposite results. CONCLUSIONS: Linc-ROR is highly expressed in the ectopic endometrium of adenomyosis, and it can promote the proliferative activity of endometrial cells by activating the PI3K-Akt pathway.


Assuntos
Endométrio/metabolismo , Fosfatidilinositol 3-Quinases/fisiologia , Proteínas Proto-Oncogênicas c-akt/fisiologia , RNA Longo não Codificante/fisiologia , Transdução de Sinais/fisiologia , Adenomiose/metabolismo , Adulto , Proliferação de Células , Endometriose/metabolismo , Endométrio/citologia , Feminino , Humanos , PTEN Fosfo-Hidrolase/fisiologia , Gravidez
18.
Neuropsychopharmacology ; 42(11): 2222-2231, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28272498

RESUMO

Cannabis use increases rates of psychotic relapse and treatment failure in schizophrenia patients. Clinical studies suggest that cannabis use reduces the efficacy of antipsychotic drugs, but there has been no direct demonstration of this in a controlled study. The present study demonstrates that exposure to the principal phytocannabinoid, Δ9-tetrahydrocannabinol (THC), reverses the neurobehavioral effects of the antipsychotic drug risperidone in mice. THC exposure did not influence D2 and 5-HT2A receptor binding, the major targets of antipsychotic action, but it lowered the brain concentrations of risperidone and its active metabolite, 9-hydroxy risperidone. As risperidone and its active metabolite are excellent substrates of the ABC transporter P-glycoprotein (P-gp), we hypothesized that THC might increase P-gp expression at the blood-brain barrier (BBB) and thus enhance efflux of risperidone and its metabolite from brain tissue. We confirmed that the brain disposition of risperidone and 9-hydroxy risperidone is strongly influenced by P-gp, as P-gp knockout mice displayed greater brain concentrations of these drugs than wild-type mice. Furthermore, we demonstrated that THC exposure increased P-gp expression in various brain regions important to risperidone's antipsychotic action. We then showed that THC exposure did not influence the neurobehavioral effects of clozapine. Clozapine shares a very similar antipsychotic mode of action to risperidone, but unlike risperidone is not a P-gp substrate. Our results imply that clozapine or non-P-gp substrate antipsychotic drugs may be better first-line treatments for schizophrenia patients with a history of cannabis use.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Antipsicóticos/farmacologia , Encéfalo/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Animais , Encéfalo/efeitos dos fármacos , Clozapina/farmacologia , Relação Dose-Resposta a Droga , Dronabinol/farmacologia , Regulação da Expressão Gênica/genética , Locomoção/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ligação Proteica/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-fos/metabolismo , Racloprida/farmacocinética , Receptor 5-HT2A de Serotonina/metabolismo , Receptores de Dopamina D2/metabolismo , Reflexo de Sobressalto/efeitos dos fármacos , Risperidona/farmacologia , Fatores de Tempo , Trítio/farmacocinética
19.
Oncogene ; 36(14): 1991-2001, 2017 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-27721412

RESUMO

Cancer cells depend on glutamine to sustain their increased proliferation and manage oxidative stress, yet glutamine is often depleted at tumor sites owing to excessive cellular consumption and poor vascularization. We have previously reported that p53 protein, although a well-known tumor suppressor, can contribute to cancer cell survival and adaptation to low-glutamine conditions. However, the TP53 gene is frequently mutated in tumors, and the role of mutant p53 (mutp53) in response to metabolic stress remains unclear. Here, we demonstrate that tumor-associated mutp53 promotes cancer cell survival upon glutamine deprivation both in vitro and in vivo. Interestingly, cancer cells expressing mutp53 proteins are more resistant to glutamine deprivation than cells with wild-type p53. Depletion of endogenous mutp53 protein in human lymphoma cells leads to cell sensitivity to glutamine withdrawal, whereas expression of mutp53 in p53 null cells results in resistance to glutamine deprivation. Furthermore, we found that mutp53 proteins hyper-transactivate p53-target gene CDKN1A upon glutamine deprivation, thus triggering cell cycle arrest and promoting cell survival. Together, our results reveal an unidentified mechanism by which mutp53 confers oncogenic functions by promoting cancer cell adaptation to metabolic stress.


Assuntos
Inibidor de Quinase Dependente de Ciclina p21/genética , Glutamina/metabolismo , Mutação , Neoplasias/genética , Neoplasias/patologia , Proteína Supressora de Tumor p53/genética , Animais , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Regulação Neoplásica da Expressão Gênica , Glutamina/deficiência , Células HCT116 , Humanos , Camundongos , Camundongos Nus , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Neoplasias/metabolismo , Estresse Fisiológico/genética , Proteína Supressora de Tumor p53/metabolismo , Regulação para Cima/genética
20.
Transplant Proc ; 48(9): 3203-3206, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27932181

RESUMO

Anesthesia for patients with moderate aortic stenosis accompanied by atrial fibrillation during high-risk surgery such as liver transplantation remains a challenge in maintaining control of heart rate and maintenance of cardiac output. The action of terlipressin on vasopressin receptors (mainly V1 receptors) leads to splanchnic vasoconstriction and is the key mechanism responsible for increasing systemic vascular resistance and reducing heart rate. We report successful anesthetic management using low-dose terlipressin infusion in an elderly patient who had moderate aortic stenosis with atrial fibrillation during urgent deceased-donor liver transplantation.


Assuntos
Anestésicos/uso terapêutico , Estenose da Valva Aórtica/complicações , Fibrilação Atrial/complicações , Transplante de Fígado/métodos , Lipressina/análogos & derivados , Idoso , Feminino , Humanos , Lipressina/uso terapêutico , Masculino , Terlipressina
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