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1.
Langmuir ; 40(8): 4489-4495, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38369881

RESUMO

The efficient removal of radioactive iodine from an aqueous solution is largely dependent on the adsorbent materials employed. In this work, we report a calix[4]pyrrole-based nanofilm and its application for the rapid removal of iodine from water. The nanofilm was synthesized through a confined dynamic condensation of tetra hydrazide calix[4]pyrrole with 1,3,5-tri-(4-formylphenyl) aldehyde at the air/dimethyl sulfoxide (DMSO) interface. The thickness of the obtained nanofilm is ∼35 nm, enabling fast mass transfer and a high ratio of accessible binding sites for iodine. The pseudo-second-order rate constant of the nanofilm for iodine is ∼0.061 g g-1 min-1, 3 orders of magnitude higher than most reported adsorbent materials. Flow-through nanofiltration tests demonstrated that the nanofilm has an adsorption capacity of 1.48 g g-1, a high removal efficiency, and good reusability. The mechanism study revealed that the moieties of Schiff base, pyrrole, and aromatic rings play a key role for binding iodine. We believe this work provides not only a new strategy for the efficient removal of radioactive iodine from water but also new ideas for designing efficient iodine adsorbents.

2.
Nat Methods ; 17(10): 985-988, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32994567

RESUMO

Thorough quality assessment of novel interactions identified by proteome-wide cross-linking mass spectrometry (XL-MS) studies is critical. Almost all current XL-MS studies have validated cross-links against known three-dimensional structures of representative protein complexes. Here, we provide theoretical and experimental evidence demonstrating that this approach can drastically underestimate error rates for proteome-wide XL-MS datasets, and propose a comprehensive set of four data-quality metrics to address this issue.


Assuntos
Espectrometria de Massas/métodos , Proteoma , Proteômica/métodos , Reagentes de Ligações Cruzadas/química , Bases de Dados de Proteínas , Humanos , Conformação Proteica , Reprodutibilidade dos Testes
3.
Nucleic Acids Res ; 49(16): 9327-9341, 2021 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-34390347

RESUMO

The DNA mismatch repair (MMR) factor Mlh1-Pms1 contains long intrinsically disordered regions (IDRs) whose exact functions remain elusive. We performed cross-linking mass spectrometry to identify interactions within Mlh1-Pms1 and used this information to insert FRB and FKBP dimerization domains into their IDRs. Baker's yeast strains bearing these constructs were grown with rapamycin to induce dimerization. A strain containing FRB and FKBP domains in the Mlh1 IDR displayed a complete defect in MMR when grown with rapamycin. but removing rapamycin restored MMR functions. Strains in which FRB was inserted into the IDR of one MLH subunit and FKBP into the other subunit were also MMR defective. The MLH complex containing FRB and FKBP domains in the Mlh1 IDR displayed a rapamycin-dependent defect in Mlh1-Pms1 endonuclease activity. In contrast, linking the Mlh1 and Pms1 IDRs through FRB-FKBP dimerization inappropriately activated Mlh1-Pms1 endonuclease activity. We conclude that dynamic and coordinated rearrangements of the MLH IDRs both positively and negatively regulate how the MLH complex acts in MMR. The application of the FRB-FKBP dimerization system to interrogate in vivo functions of a critical repair complex will be useful for probing IDRs in diverse enzymes and to probe transient loss of MMR on demand.


Assuntos
Reparo de Erro de Pareamento de DNA/genética , Proteínas Intrinsicamente Desordenadas/genética , Proteína 1 Homóloga a MutL/genética , Proteínas MutL/genética , Proteínas de Saccharomyces cerevisiae/genética , Domínios Proteicos/genética , Multimerização Proteica/genética , Saccharomyces cerevisiae/genética , Sirolimo/farmacologia , Proteínas de Ligação a Tacrolimo/genética
4.
Lupus ; 31(8): 927-938, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35531921

RESUMO

OBJECTIVE: To study the association of α2,6-sialic acid (SIA) content in serum IgG anti-dsDNA with human systemic lupus erythematosus disease activity index (SLEDAI) and the effect of sialylated and desialylated (deSIA) IgG anti-dsDNA on lupus B cells. METHODS: Blood from lupus patients was collected to determine the ratio of SIA in isolated IgG anti-dsDNA over serum IgG anti-dsDNA (SIA/IgG anti-dsDNA) ratios, which were plotted against SLEDAI using a receiver-operating-characteristics curve. Lupus B cells were cultured in vitro with chimeric sialylated IgG anti-dsDNA and its deSIA form. Culture supernatants were assayed for anti-inflammatory IL-10 and SIA/IgG anti-dsDNA ratios, which were compared among different pre-treatment groups using t-tests. RESULTS: The area-under-the-curve (AUC) for anti-dsDNA levels against SLEDAI was 0.791 positively (95% confidence interval [C.I.]: 0.699-0.884) and SIA/IgG anti-dsDNA ratios against SLEDAI yielded an AUC of 0.705 inversely (95% C.I: 0.601-0.809): not significantly different. SIA/IgG anti-dsDNA ratios discriminated significantly between patients without and patients with proteinuria (p = .046). SIA/IgG anti-dsDNA ratios correlated significantly and positively with serum C3c and C4 levels. Pre-treatment with IgG anti-dsDNA and its immune complexes (dsDNA/IgG anti-dsDNA IC) induced higher IL-10 from lupus B cells than medium pre-treatment (most p < .01 from day 2 to day 5 culture). DeSIA IgG anti-dsDNA IC induced lower IL-10 (p < .05) and lower SIA/IgG anti-dsDNA ratios (p < .001) from lupus B cells than medium and dsDNA pre-treatment. CONCLUSION: α2,6-SIA/IgG anti-dsDNA ratios inversely forecasted SLEDAI scores. Possible mechanisms may be due to the different effects of sialylated and deSIA IgG anti-dsDNA on lupus B cells in terms of IL-10 secretion and SIA/IgG anti-dsDNA ratios.


Assuntos
Lúpus Eritematoso Sistêmico , Ácido N-Acetilneuramínico , Anticorpos Antinucleares , DNA , Humanos , Imunoglobulina G , Interleucina-10 , Projetos Piloto
5.
Mol Cell Proteomics ; 19(3): 554-568, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31839598

RESUMO

Protein-protein interactions play a vital role in nearly all cellular functions. Hence, understanding their interaction patterns and three-dimensional structural conformations can provide crucial insights about various biological processes and underlying molecular mechanisms for many disease phenotypes. Cross-linking mass spectrometry (XL-MS) has the unique capability to detect protein-protein interactions at a large scale along with spatial constraints between interaction partners. The inception of MS-cleavable cross-linkers enabled the MS2-MS3 XL-MS acquisition strategy that provides cross-link information from both MS2 and MS3 level. However, the current cross-link search algorithm available for MS2-MS3 strategy follows a "MS2-centric" approach and suffers from a high rate of mis-identified cross-links. We demonstrate the problem using two new quality assessment metrics ["fraction of mis-identifications" (FMI) and "fraction of interprotein cross-links from known interactions" (FKI)]. We then address this problem, by designing a novel "MS3-centric" approach for cross-link identification and implementing it as a search engine named MaXLinker. MaXLinker outperforms the currently popular search engine with a lower mis-identification rate, and higher sensitivity and specificity. Moreover, we performed human proteome-wide cross-linking mass spectrometry using K562 cells. Employing MaXLinker, we identified a comprehensive set of 9319 unique cross-links at 1% false discovery rate, comprising 8051 intraprotein and 1268 interprotein cross-links. Finally, we experimentally validated the quality of a large number of novel interactions identified in our study, providing a conclusive evidence for MaXLinker's robust performance.


Assuntos
Mapeamento de Interação de Proteínas/métodos , Proteômica/métodos , Humanos , Células K562 , Espectrometria de Massas , Peptídeos/metabolismo , Proteoma , Sensibilidade e Especificidade
6.
Molecules ; 27(7)2022 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-35408591

RESUMO

Various nanoparticles have been applied as chemical demulsifiers to separate the crude-oil-in-water emulsion in the petroleum industry, including graphene oxide (GO). In this study, the Janus amphiphilic graphene oxide (JGO) was prepared by asymmetrical chemical modification on one side of the GO surface with n-octylamine. The JGO structure was verified by Fourier-transform infrared spectra (FTIR), transmission electron microscopy (TEM), and contact angle measurements. Compared with GO, JGO showed a superior ability to break the heavy oil-in-water emulsion with a demulsification efficiency reaching up to 98.25% at the optimal concentration (40 mg/L). The effects of pH and temperature on the JGO's demulsification efficiency were also investigated. Based on the results of interfacial dilatational rheology measurement and molecular dynamic simulation, it was speculated that the intensive interaction between JGO and asphaltenes should be responsible for the excellent demulsification performance of JGO. This work not only provided a potential high-performance demulsifier for the separation of crude-oil-in-water emulsion, but also proposed novel insights to the mechanism of GO-based demulsifiers.


Assuntos
Grafite , Petróleo , Emulsões/química , Simulação de Dinâmica Molecular , Água
7.
Langmuir ; 37(33): 10061-10070, 2021 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-34392688

RESUMO

Colloidal stability of modified graphene oxide (GO) is fundamental for its practical applications. Meanwhile, most of the investigations mainly focused on the nanosheets modified by a certain amount of modifiers and neglected the effects of the modification degree, which could vary the physical and chemical properties of modified GO and significantly affect its stability in solution. To the best of our knowledge, this study initially investigated the impact of modification degrees on the colloidal stability of graphene-based amphiphilic Janus nanosheets (JGO) via both experimental and theoretical approaches. The prepared JGO, asymmetrically grafted by dodecylamine, exhibited a direct relation between the modification degree and nanosheet thickness, refractive index, electrostatic properties, hydrophobicity, and the ultimate colloidal stability. In addition, the ionic strength imposed distinctive influences on the aggregation behavior of JGO. Based on the comparison between experimental results and theoretical calculation, it was revealed that the JGO should be modeled as two-dimensional (2D) nanosheets in pure water and be treated as 3D spherical particles in electrolyte solutions for the prediction with the extended Derjaguin-Landau-Verwey-Overbeek theory.

8.
Molecules ; 26(22)2021 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-34834069

RESUMO

In this work, molecular dynamics simulations were performed to study the pH-induced structural transitions for a CTAB/p-toluic acid solution. Spherical and cylindrical micelles were obtained for aqueous surfactants at pH 2 and 7, respectively, which agrees well with the experimental observations. The structural properties of two different micelles were analyzed through the density distributions of components and the molecular orientations of CTA+ and toluic acid inside the micelles. It was found that the bonding interactions between CTA+ and toluic in spherical and cylindrical micelles are very different. Almost all the ionized toluic acid (PTA-) in the solution at pH 7 was solubilized into the micelles, and it was located in the CTA+ headgroups region. Additionally, the bonding between surfactant CTA+ and PTA- was very tight due to the electrostatic interactions. The PTA- that penetrated into the micelles effectively screened the electrostatic repulsion among the cationic headgroups, which is considered to be crucial for maintaining the cylindrical micellar shape. As the pH decreased, the carboxyl groups were protonated. The hydration ability of neutral carboxyl groups weakened, resulting in deeper penetration into the micelles. Meanwhile, their bonding interactions with surfactant headgroups also weakened. Accompanied by the strengthen of electrostatic repulsion among the positive headgroups, the cylindrical micelle was broken into spherical micelles. Our work provided an atomic-level insights into the mechanism of pH-induced structural transitions of a CTAB/p-toluic solution, which is expected to be useful for further understanding the aggregate behavior of mixed cationic surfactants and aromatic acids.

9.
Hu Li Za Zhi ; 68(4): 72-80, 2021 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-34337705

RESUMO

BACKGROUND & PROBLEM: The provision by nurses of effective swallowing assessments and eating safety guidance improves eating safety in the elderly. The authors of this study found that elderly clients experienced a high proportion of aspiration pneumonia after choking episodes and that the rate of implementation of eating safety guidance among these clients by nursing staff was only 64.6%. The problems identified included a lack of education and training related to eating safety for the elderly, inconsistent health education methods, oral health education only, lack of unified health education content, and lack of proper health education guidance aids. PURPOSE: To raise the rate of implementing eating safety guidance among the elderly from 64.6% to 90.0%. RESOLUTION: The project included promoting an eating safety guidance workflow for the elderly using cross-team collaboration, using human body models and food models, promoting oral healthcare and oral exercises, using multilingual instructional leaflets and videos on eating safety and hygiene education, promoting a treasure hunting activity to the elderly related to eating safely using a food texture selection chart, and implementing a workshop on simulated eating safety scenarios. RESULTS: After project implementation, the eating safety guidance implementation rate increased from 64.6% to 92.1%, demonstrating that the intervention measures achieved remarkable results. CONCLUSIONS: Formulating care procedures and cooperating across teams to draft concrete and feasible improvement measures effectively increased the rate of eating safety guidance implementation for elderly clients by nursing staff.


Assuntos
Recursos Humanos de Enfermagem , Pneumonia Aspirativa , Idoso , Atenção à Saúde , Exercício Físico , Humanos
10.
Traffic ; 19(6): 421-435, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29582528

RESUMO

Various densely charged polycationic species, whether of biological or synthetic origin, can penetrate human cells, albeit with variable efficiencies. The molecular underpinnings involved in such transport remain unclear. Herein, we assemble 1, 2 or 3 copies of the HIV peptide TAT on a synthetic scaffold to generate branched cell-permeable prototypes with increasing charge density. We establish that increasing TAT copies dramatically increases the cell penetration efficiency of the peptides while simultaneously enabling the efficient cytosolic delivery of macromolecular cargos. Cellular entry involves the leaky fusion of late endosomal membranes enriched with the anionic lipid BMP. Derivatives with multiple TAT branches induce the leakage of BMP-containing lipid bilayers, liposomal flocculation, fusion and an increase in lamellarity. In contrast, while the monomeric counterpart 1TAT binds to the same extent and causes liposomal flocculation, 1TAT does not cause leakage, induce fusion or a significant increase in lamellarity. Overall, these results indicate that an increase in charge density of these branched structures leads to the emergence of lipid specific membrane-disrupting and cell-penetrating activities.


Assuntos
Endossomos/metabolismo , Lipídeos/química , Peptídeos/metabolismo , Linhagem Celular Tumoral , Citosol/metabolismo , Células HeLa , Humanos , Membranas Intracelulares/metabolismo , Bicamadas Lipídicas/metabolismo , Lipossomos/metabolismo
11.
Semin Thromb Hemost ; 46(5): 606-621, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31614390

RESUMO

Thrombosis is characterized by the formation of in vivo blood clots that are localized within arterial or venous blood vessels. These thrombi form beyond the need for physiologically healthy hemostatic responses and can lead to significant medical issues for affected individuals. Unfortunately, the existing standard-of-care therapies for treating thrombosis are systemic in their therapeutic design; therefore, they interfere with the patient's physiological hemostasis. Examples of the severe clinical side effects commonly associated with currently available therapies include, but are not limited to, bleeding complications. Therefore, there is a profound demand for novel therapeutic interventions that can circumvent these debilitating complications, while offering improved therapeutic efficacy. Recent advancements in nanotechnology present an opportunity to develop novel and improved drug delivery systems to meet this clinical demand. Preclinical investigations have begun to uncover the potential of nanotechnology, particularly in the treatment of thrombosis and also in nonhemostatic cardiovascular diseases. This article reviews recent preclinical studies aimed at developing a diverse array of different nanotechnologies for treating thrombosis as well as heart diseases. This review will also outline the limitations with current nanotechnologies and what challenges need to be overcome to translate these novel therapies to the clinic.


Assuntos
Doenças Cardiovasculares/tratamento farmacológico , Nanotecnologia/métodos , Trombose/terapia , Humanos
12.
Angew Chem Int Ed Engl ; 59(21): 8153-8159, 2020 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-32196883

RESUMO

Diphosphine ligands that merge both axial and P-centered chirality may exhibit superior or unique properties. Herein we report the diastereoselective introduction of P-centered chirality at the 2-position of the axially chiral 2'-(phosphine oxide)-1,1'-binaphthyl scaffold. A lithium-bromide exchange reaction of a 2-bromo-2'-(phosphine oxide)-1,1'-binaphthyl and treatment with dichlorophosphines followed by a nucleophilic organometallic reagent afforded unsymmetrical 2-phosphino-2'-(phosphine oxide)-1,1'-binaphthyls with binaphthyl axial chirality and one or two phosphorus stereocenters with a variety of P substituents. The final diastereomerically pure 2,2'-bisphosphino-1,1'-binaphthyls were obtained by reduction of the phosphine oxide directing group. Preliminary results demonstrated that a ligand with this hybrid chirality could induce higher stereoselectivity in the metal-complex-catalyzed asymmetric hydrogenation of a dialkyl ketone.

13.
Am J Gastroenterol ; 114(3): 437-445, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30807294

RESUMO

OBJECTIVES: This study assessed the effectiveness, adverse events, patient adherence, and costs of modified dual therapy compared with bismuth-containing quadruple therapy for treating Helicobacter pylori infection in Chinese patients. We also sought to determine whether modified dual therapy could be used as an alternative first-line treatment for H. pylori infection. METHODS: A total of 232 H. pylori-infected, treatment-naive patients were enrolled in this open-label, randomized controlled clinical trial. Patients were randomly allocated into 2 groups: the 14-day modified dual therapy group and the bismuth-containing quadruple therapy group. Eradication rates, drug-related adverse events, patient compliance, and drug costs were compared between the 2 groups. RESULTS: The modified dual therapy group achieved eradication rates of 87.9%, 91.1%, and 91.1% as determined by the intention-to-treat, per-protocol, and modified intention-to-treat analyses, respectively. The eradication rates were similar compared with the bismuth-containing quadruple therapy group: 89.7%, 91.2%, and 90.4%. In addition, modified dual therapy ameliorated variations in the CYP2C19, IL-1B-511, and H. pylori VacA genotypes. There were no significant differences in the compliance rates between the 2 groups. The modified dual therapy group exhibited significantly less overall side effects compared with the bismuth-containing quadruple therapy group (P < 0.001). Furthermore, the cost of medications in the modified dual therapy was lower compared with that in the bismuth-containing quadruple therapy. CONCLUSIONS: Modified dual therapy at high dose and administration frequency is equally effective and safer and less costly compared with bismuth-containing quadruple therapy.


Assuntos
Amoxicilina/uso terapêutico , Antibacterianos/uso terapêutico , Antiulcerosos/uso terapêutico , Claritromicina/uso terapêutico , Esomeprazol/uso terapêutico , Infecções por Helicobacter/tratamento farmacológico , Compostos Organometálicos/uso terapêutico , Adulto , Testes Respiratórios , Isótopos de Carbono , Custos de Medicamentos , Farmacorresistência Bacteriana , Quimioterapia Combinada , Feminino , Helicobacter pylori , Humanos , Masculino , Adesão à Medicação , Pessoa de Meia-Idade , Resultado do Tratamento , Ureia
14.
Biomacromolecules ; 20(9): 3592-3600, 2019 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-31448896

RESUMO

Drug carriers typically require both stealth and targeting properties to minimize nonspecific interactions with healthy cells and increase specific interaction with diseased cells. Herein, the assembly of targeted poly(ethylene glycol) (PEG) particles functionalized with cyclic peptides containing Arg-Gly-Asp (RGD) (ligand) using a mesoporous silica templating method is reported. The influence of PEG molecular weight, ligand-to-PEG molecule ratio, and particle size on cancer cell targeting to balance stealth and targeting of the engineered PEG particles is investigated. RGD-functionalized PEG particles (PEG-RGD particles) efficiently target U-87 MG cancer cells under static and flow conditions in vitro, whereas PEG and cyclic peptides containing Arg-Asp-Gly (RDG)-functionalized PEG (PEG-RDG) particles display negligible interaction with the same cells. Increasing the ligand-to-PEG molecule ratio improves cell targeting. In addition, the targeted PEG-RGD particles improve cell uptake via receptor-mediated endocytosis, which is desirable for intracellular drug delivery. The PEG-RGD particles show improved tumor targeting (14% ID g-1) when compared with the PEG (3% ID g-1) and PEG-RDG (7% ID g-1) particles in vivo, although the PEG-RGD particles show comparatively higher spleen and liver accumulation. The targeted PEG particles represent a platform for developing particles aimed at balancing nonspecific and specific interactions in biological systems.


Assuntos
Sistemas de Liberação de Medicamentos , Neoplasias/tratamento farmacológico , Oligopeptídeos/farmacologia , Polietilenoglicóis/farmacologia , Animais , Linhagem Celular Tumoral , Citoplasma/efeitos dos fármacos , Endocitose/efeitos dos fármacos , Humanos , Ligantes , Oligopeptídeos/química , Polietilenoglicóis/química , Transdução de Sinais/efeitos dos fármacos , Dióxido de Silício/química , Dióxido de Silício/farmacologia , Propriedades de Superfície
15.
J Biol Chem ; 292(3): 847-861, 2017 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-27923812

RESUMO

Cell-penetrating peptides (CPPs) are well established as delivery agents for otherwise cell-impermeable cargos. CPPs can also theoretically be used to modulate intracellular processes. However, their susceptibility to proteolytic degradation often limits their utility in these applications. Previous studies have explored the consequences for cellular uptake of converting the residues in CPPs from l- to d-stereochemistry, but conflicting results have been reported and specific steps en route to intracellular activity have not been explored. Here we use dimeric fluorescence TAT as a model CPP to explore the broader consequences of l- to d-stereochemical conversion. We show that inversion of chirality provides protease resistance without altering the overall mode of cellular entry, a process involving endocytic uptake followed by endosomal escape and cytosolic access. However, whereas inversion of chirality reduces endocytic uptake, the d-peptide, once in the endosome, is significantly more prone to escape than its l-counterpart. Moreover, the d-peptide is retained in the cytosol of cells for several days, whereas the l-peptide is degraded within hours. Notably, while the l-peptide is relatively innocuous to cells, the d-peptide exerts a prolonged anti-proliferative activity. Together, our results establish connections between chirality, protease resistance, cellular penetration, and intracellular activity that may be useful for the development of future delivery agents with improved properties.


Assuntos
Aminoácidos/química , Peptídeos Penetradores de Células/química , Modelos Moleculares , Aminoácidos/farmacocinética , Aminoácidos/farmacologia , Peptídeos Penetradores de Células/farmacocinética , Peptídeos Penetradores de Células/farmacologia , Endossomos/química , Endossomos/metabolismo , Células HeLa , Humanos
16.
Small ; 14(39): e1802342, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30156378

RESUMO

Interfacial self-assembly is a powerful organizational force for fabricating functional nanomaterials, including nanocarriers, for imaging and drug delivery. Herein, the interfacial self-assembly of pH-responsive metal-phenolic networks (MPNs) on the liquid-liquid interface of oil-in-water emulsions is reported. Oleic acid emulsions of 100-250 nm in diameter are generated by ultrasonication, to which poly(ethylene glycol) (PEG)-based polyphenolic ligands are assembled with simultaneous crosslinking by metal ions, thus forming an interfacial MPN. PEG provides a protective barrier on the emulsion phase and renders the emulsion low fouling. The MPN-coated emulsions have a similar size and dispersity, but an enhanced stability when compared with the uncoated emulsions, and exhibit a low cell association in vitro, a blood circulation half-life of ≈50 min in vivo, and are nontoxic to healthy mice. Furthermore, a model anticancer drug, doxorubicin, can be encapsulated within the emulsion phase at a high loading capacity (≈5 fg of doxorubicin per emulsion particle). The MPN coating imparts pH-responsiveness to the drug-loaded emulsions, leading to drug release at cell internalization pH and a potent cell cytotoxicity. The results highlight a straightforward strategy for the interfacial nanofabrication of pH-responsive emulsion-MPN systems with potential use in biomedical applications.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Emulsões/química , Nanoestruturas/química , Animais , Doxorrubicina/química , Concentração de Íons de Hidrogênio , Camundongos , Ácido Oleico/química , Polietilenoglicóis/química
17.
J Biol Chem ; 291(15): 7902-14, 2016 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-26888085

RESUMO

Arginine-rich peptides can penetrate cells and consequently be used as delivery agents in various cellular applications. The activity of these reagents is often context-dependent, and the parameters that impact cell entry are not fully understood, giving rise to variability and limiting progress toward their usage. Herein, we report that the cytosolic penetration of linear polyarginine peptides is dependent on the oxidation state of the cell. In particular, we find that hypoxia and cellular antioxidants inhibit cell penetration. In contrast, oxidants promote cytosolic cell entry with an efficiency proportional to the level of reactive oxygen species generated within membranes. Moreover, an antibody that binds to oxidized lipids inhibits cell penetration, whereas extracellularly administered pure oxidized lipids enhance peptide transport into cells. Overall, these data indicate that oxidized lipids are capable of mediating the transport of polyarginine peptides across membranes. These data may also explain variability in cell-penetrating peptide performance in different experimental conditions. These new findings therefore provide new opportunities for the rational design of future cell-permeable compounds and for the optimization of delivery protocols.


Assuntos
Membrana Celular/metabolismo , Peptídeos Penetradores de Células/metabolismo , Citosol/metabolismo , Fibroblastos/metabolismo , Peptídeos/metabolismo , Transporte Biológico , Técnicas de Cultura de Células , Linhagem Celular , Humanos , Lipídeos de Membrana/metabolismo , Oxirredução , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo
18.
Nat Methods ; 11(8): 861-7, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24930129

RESUMO

We report that a tetramethylrhodamine-labeled dimer of the cell-penetrating peptide TAT, dfTAT, penetrates live cells by escaping from endosomes with high efficiency. By mediating endosomal leakage, dfTAT also delivers proteins into cultured cells after a simple co-incubation procedure. We achieved cytosolic delivery in several cell lines and primary cells and observed that only a relatively small amount of material remained trapped inside endosomes. Delivery did not require a binding interaction between dfTAT and a protein, multiple molecules could be delivered simultaneously, and delivery could be repeated. dfTAT-mediated delivery did not noticeably affect cell viability, cell proliferation or gene expression. dfTAT-based intracellular delivery should be useful for cell-based assays, cellular imaging applications and the ex vivo manipulation of cells.


Assuntos
Endossomos/metabolismo , Proteínas/administração & dosagem , Proliferação de Células
19.
J Biol Chem ; 289(21): 15044-51, 2014 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-24700461

RESUMO

Various engineering applications have been utilized to deliver molecules and compounds in both innate and biological settings. In the context of biological applications, the timely delivery of molecules can be critical for cellular and organ function. As such, previous studies have demonstrated the superiority of long-term protein delivery, by way of protein tethering onto bioengineered scaffolds, compared with conventional delivery of soluble protein in vitro and in vivo. Despite such benefits little knowledge exists regarding the stability, release kinetics, longevity, activation of intracellular pathway, and functionality of these proteins over time. By way of example, here we examined the stability, degradation and functionality of a protein, glial-derived neurotrophic factor (GDNF), which is known to influence neuronal survival, differentiation, and neurite morphogenesis. Enzyme-linked immunosorbent assays (ELISA) revealed that GDNF, covalently tethered onto polycaprolactone (PCL) electrospun nanofibrous scaffolds, remained present on the scaffold surface for 120 days, with no evidence of protein leaching or degradation. The tethered GDNF protein remained functional and capable of activating downstream signaling cascades, as revealed by its capacity to phosphorylate intracellular Erk in a neural cell line. Furthermore, immobilization of GDNF protein promoted cell survival and differentiation in culture at both 3 and 7 days, further validating prolonged functionality of the protein, well beyond the minutes to hours timeframe observed for soluble proteins under the same culture conditions. This study provides important evidence of the stability and functionality kinetics of tethered molecules.


Assuntos
Proteínas Imobilizadas/metabolismo , Nanofibras/química , Poliésteres/química , Alicerces Teciduais/química , Animais , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Feminino , Fator Neurotrófico Derivado de Linhagem de Célula Glial/química , Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Fator Neurotrófico Derivado de Linhagem de Célula Glial/farmacologia , Proteínas Imobilizadas/química , Proteínas Imobilizadas/farmacologia , Immunoblotting , Camundongos , Microscopia Eletrônica de Varredura , Nanofibras/ultraestrutura , Células-Tronco Neurais/efeitos dos fármacos , Células-Tronco Neurais/metabolismo , Gravidez , Estabilidade Proteica , Pesquisa com Células-Tronco , Engenharia Tecidual/métodos , Cicatrização
20.
Bioorg Med Chem ; 23(5): 1123-34, 2015 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-25650311

RESUMO

Proteinase 3 (Pr3), and human neutrophil elastase (HNE) are two major neutrophilic serine proteases (NsPs) expressed in neutrophil azurophil granules. Emerging data suggest that excessive release of proteases mediates tissue damage, and therefore prolonged neutrophil accumulation has an important role in the pathogenesis of many diseases. Thus, HNE and Pr3 inhibitors may prove to be targets for the generation of agents in the treatment of neutrophilic inflammatory disease. Sivelestat is the only commercially available selective HNE inhibitor. Therefore, sivelestat was chosen as the model structure in an attempt to obtain more potent anti-NsPs agents. In the present study, a series 2-aminobenzaldehyde oxime and 2-aminobenzoate analogs were synthesized and their inhibitory effects on NsPs (CatG, Pr3, and HNE) were determined, respectively. The results of structure-activity relationships studies concluded that a hydroxyl oxime moiety plays an important role in ligand-enzyme affinity through hydrogen bonding. As compound 6 had more potency and showed dual inhibitory effects on NE and Pr3, both in vitro and in vivo experiments were carried out to evaluate its selectivity, effects in cell-based assays, and efficacy in models of inflammation and damage. Compound 6 had the potential to reduce paw edema induced by LPS and HNE, as well as acute lung injury, and may be approved as a candidate for the development of new agents in the treatment of neutrophilic inflammatory diseases.


Assuntos
Benzaldeídos/síntese química , Benzaldeídos/farmacologia , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Elastase de Leucócito/antagonistas & inibidores , Mieloblastina/antagonistas & inibidores , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/enzimologia , Animais , Benzaldeídos/química , Edema/prevenção & controle , Inibidores Enzimáticos/química , Humanos , Lipopolissacarídeos/farmacologia , Pulmão/efeitos dos fármacos , Pulmão/enzimologia , Camundongos , Neutrófilos/efeitos dos fármacos , Neutrófilos/enzimologia , Neutrófilos/metabolismo , Oximas/química , Peroxidase/antagonistas & inibidores , Peroxidase/metabolismo , Relação Estrutura-Atividade , Superóxidos/metabolismo
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