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1.
Nat Commun ; 11(1): 5062, 2020 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-33033254

RESUMO

Septins are GTP-binding proteins involved in diverse cellular processes including division and membrane remodeling. Septins form linear, palindromic heteromeric complexes that can assemble in filaments and higher-order structures. Structural studies revealed various septin architectures, but questions concerning assembly-dynamics and -pathways persist. Here we used high-speed atomic force microscopy (HS-AFM) and kinetic modeling which allowed us to determine that septin filament assembly was a diffusion-driven process, while formation of higher-order structures was complex and involved self-templating. Slightly acidic pH and increased monovalent ion concentrations favor filament-assembly, -alignment and -pairing. Filament-alignment and -pairing further favored diffusion-driven assembly. Pairing is mediated by the septin N-termini face, and may occur symmetrically or staggered, likely important for the formation of higher-order structures of different shapes. Multilayered structures are templated by the morphology of the underlying layers. The septin C-termini face, namely the C-terminal extension of Cdc12, may be involved in membrane binding.


Assuntos
Microscopia de Força Atômica , Septinas/metabolismo , Simulação por Computador , Difusão , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Cinética , Lipídeos/química , Domínios Proteicos , Septinas/ultraestrutura , Eletricidade Estática
2.
Nat Commun ; 11(1): 4955, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33009385

RESUMO

The light-harvesting-reaction center complex (LH1-RC) from the purple phototrophic bacterium Thiorhodovibrio strain 970 exhibits an LH1 absorption maximum at 960 nm, the most red-shifted absorption for any bacteriochlorophyll (BChl) a-containing species. Here we present a cryo-EM structure of the strain 970 LH1-RC complex at 2.82 Å resolution. The LH1 forms a closed ring structure composed of sixteen pairs of the αß-polypeptides. Sixteen Ca ions are present in the LH1 C-terminal domain and are coordinated by residues from the αß-polypeptides that are hydrogen-bonded to BChl a. The Ca2+-facilitated hydrogen-bonding network forms the structural basis of the unusual LH1 redshift. The structure also revealed the arrangement of multiple forms of α- and ß-polypeptides in an individual LH1 ring. Such organization indicates a mechanism of interplay between the expression and assembly of the LH1 complex that is regulated through interactions with the RC subunits inside.


Assuntos
Cálcio/metabolismo , Microscopia Crioeletrônica , Complexos de Proteínas Captadores de Luz/ultraestrutura , Peptídeos/metabolismo , Fotossíntese , Sequência de Aminoácidos , Bacterioclorofila A/metabolismo , Sítios de Ligação , Chromatiaceae/metabolismo , Detergentes/química , Dimerização , Complexos de Proteínas Captadores de Luz/química , Complexos de Proteínas Captadores de Luz/metabolismo , Lipídeos/química , Peptídeos/química , Quinonas/química
3.
Cells ; 9(9)2020 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-32899484

RESUMO

Hybrid nanoparticles from lipidic and polymeric components were assembled to serve as vehicles for the transfection of messenger RNA (mRNA) using different portions of the cationic lipid DOTAP (1,2-Dioleoyl-3-trimethylammonium-propane) and the cationic biopolymer protamine as model systems. Two different sequential assembly approaches in comparison with a direct single-step protocol were applied, and molecular organization in correlation with biological activity of the resulting nanoparticle systems was investigated. Differences in the structure of the nanoparticles were revealed by thorough physicochemical characterization including small angle neutron scattering (SANS), small angle X-ray scattering (SAXS), and cryogenic transmission electron microscopy (cryo-TEM). All hybrid systems, combining lipid and polymer, displayed significantly increased transfection in comparison to lipid/mRNA and polymer/mRNA particles alone. For the hybrid nanoparticles, characteristic differences regarding the internal organization, release characteristics, and activity were determined depending on the assembly route. The systems with the highest transfection efficacy were characterized by a heterogenous internal organization, accompanied by facilitated release. Such a system could be best obtained by the single step protocol, starting with a lipid and polymer mixture for nanoparticle formation.


Assuntos
Biopolímeros/química , Lipídeos/química , Nanopartículas/química , RNA Mensageiro/metabolismo , Transfecção/métodos , Animais , Linhagem Celular , Ácidos Graxos Monoinsaturados/química , Feminino , Heparina/química , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Imagem Óptica , Tamanho da Partícula , Compostos de Amônio Quaternário/química , RNA Mensageiro/química
4.
Int J Nanomedicine ; 15: 4763-4778, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32753865

RESUMO

Introduction: Methotrexate exhibits poor cutaneous bioavailability and systemic side effects on topical administration, so there is an unmet need for a novel carrier and its optimized therapy. Methotrexate-loaded nanostructured lipid carriers (MTXNLCs) were formulated and characterized to determine in vitro drug release and evaluate the role of MTXNLC gel in the topical treatment of psoriasis. Methods: A solvent diffusion technique was employed to prepare MTXNLCs, which was optimized using 32 full factorial designs. The mean diameter and surface morphology of MTXNLCs was evaluated. The crystallinity of lyophilized MTXNLCs was characterized by differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD). MTXNLCs were integrated in 1% w/w Carbopol 934 P gel base, and in vitro skin deposition studies in human cadaver skin (HCS) were carried out. Results: The optimized MTXNLCs were rod-shaped, with an average particle size of 253 ± 8.65 nm, a zeta potential of -26.4±0.86 mV, and EE of 54.00±1.49%. DSC and XRD data confirmed the formation of NLCs. Significantly higher deposition of MTX was found in HCS from MTXNLC gel (71.52 ±1.13%) as compared to MTX plain gel (38.48±0.96%). In vivo studies demonstrated significant improvement in therapeutic response and reduction in local side effects with MTXNLCs-loaded gel in the topical treatment of psoriasis. Anti-psoriatic efficacy of MTXNLCs 100 ug/cm2 compared with plain MTX gel was evaluated using imiquimod (IMQ)-induced psoriasis in BALB/c mice. The topical application of MTXNLCs to the mouse ear resulted in a significant reduction of psoriatic area and severity index, oxidative stress, inflammatory cytokines like TNF-α, IL-1ß, and IL-6 and IMQ-induced histopathological alterations in mouse ear samples. Conclusion: Developed formulation of MTXNLC gel demonstrated better anti-psoriatic activity and also displayed prolonged and sustained release effect, which shows that it can be a promising alternative to existing MTX formulation for the treatment of psoriasis.


Assuntos
Composição de Medicamentos , Géis/química , Imiquimode/uso terapêutico , Inflamação/tratamento farmacológico , Lipídeos/química , Metotrexato/uso terapêutico , Nanoestruturas/química , Psoríase/tratamento farmacológico , Administração Cutânea , Administração Tópica , Animais , Catalase/metabolismo , Citocinas/metabolismo , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Glutationa/metabolismo , Humanos , Inflamação/patologia , Malondialdeído/metabolismo , Camundongos Endogâmicos BALB C , Nanoestruturas/ultraestrutura , Tamanho do Órgão , Superóxido Dismutase/metabolismo
5.
Crit Rev Ther Drug Carrier Syst ; 37(3): 205-227, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32749138

RESUMO

In this review, we describe the advances in oral drug delivery approaches for taxanes for successful therapeutic outcome. Taxanes (paclitaxel and docetaxel) have unwanted pharmacokinetic profiles when they are given in their current dosage forms. Taxanes have low bioavailability, are extensively metabolized by CYP3A, and have a high affinity for P-glycoprotein. Regardless of dosage schedule, the overall docetaxel or paclitaxel dose that a patient can tolerate at a given interval remains similar. Currently, there are no commercially available oral taxane nanoformulations, and there are still several challenges to overcome. Nano-based formulations may offer the best solutions to problems involving the safety and effectiveness of taxane delivery. Thus, further research is necessary before such taxane nanoformulations can be manufactured for clinical use.


Assuntos
Docetaxel/administração & dosagem , Paclitaxel/administração & dosagem , Administração Oral , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/química , Antineoplásicos/farmacocinética , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacocinética , Ensaios Clínicos como Assunto , Docetaxel/química , Docetaxel/farmacocinética , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/química , Composição de Medicamentos , Sistemas de Liberação de Medicamentos , Humanos , Lipídeos/administração & dosagem , Lipídeos/química , Micelas , Nanopartículas/administração & dosagem , Nanopartículas/química , Paclitaxel/química , Paclitaxel/farmacocinética
6.
Crit Rev Ther Drug Carrier Syst ; 37(3): 271-303, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32749140

RESUMO

Nanotechnology has made great contributions in the development of materials with potential application in different areas, especially in the pharmaceutical sector, where nano-systems are being intensely studied for controlled drug release. These innovative systems are composed of structures such as nanoparticles, nanoemulsions, and cyclodextrins, with the aim of promoting enhanced bioavailability of bioactive molecules. Among these nanocarriers, vesicles such as liposomes and polymersomes are considered to be promising alternatives in delivering hydrophilic and lipophilic drugs. They have different classifications according to their composition, among which are hybrid vesicles, which unlike liposomes are composed of both lipids and polymers. These vesicular systems stand out for combining the advantages of both components, overcoming the limitations of traditional systems imposed by low stability and premature release of the encapsulated active substance. The polymers applied in hybrid vesicles can make up the membrane structure itself or be employed to coat preformed vesicles. Due to the relevance of these systems, this work covers their characteristics and summarizes recent articles about them in the literature.


Assuntos
Cosméticos/administração & dosagem , Lipídeos/administração & dosagem , Nanopartículas/administração & dosagem , Nanotecnologia/métodos , Polímeros/administração & dosagem , Nanomedicina Teranóstica/métodos , Animais , Cosméticos/química , Preparações de Ação Retardada , Sistemas de Liberação de Medicamentos/métodos , Humanos , Lipídeos/química , Lipossomos/administração & dosagem , Lipossomos/química , Nanopartículas/química , Polímeros/química
7.
Int J Nanomedicine ; 15: 5253-5264, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801690

RESUMO

Background and Aim: Flibanserin (FLB) is a multifunctional serotonergic agent used for treating hypoactive sexual desire disorder in premenopausal women via oral administration. FLB has a reported limited oral bioavailability of 33% that could be attributed to the drug's first-pass metabolism. In addition, FLB has a pH-dependent solubility that could be a challenging factor for drug dissolution in the body neutral fluid, and consequently, absorption via mucosal barriers. Thus, this work aims at investigating the potential of utilizing nanostructured lipid carriers (NLCs) to overcome the aforementioned drawbacks and to enhance nose-to-brain drug delivery. Methods: Box-Behnken design was applied to explore the impact of solid lipid % (SL%, X 1), liquid lipid % (LL%, X 2), and sonication time (ST, X 3) on particle size. The optimized NLC formulation was characterized and incorporated into gellan gum in situ gel. The prepared gel was subjected to in vitro drug release, in vivo pharmacokinetic performance, and histopathological assessment in rats. Results: Statistical analysis revealed a significant negative effect for both SL% and ST on NLCs size. In contrast, a significant positive effect was observed for the LL%. The optimized formulation showed spherical shape with vesicular size of 114.63 nm. The optimized FLB-NLC in situ gel exhibited adequate stability and enhanced in vitro release compared to raw FLB control gel. The plasma and brain concentrations of the drug after nasal administration in rats increased by more than 3-6-fold, respectively, compared to raw FLB in situ gel. In addition, the histopathological studies revealed the absence of any pathological signs. Conclusion: The aforementioned results highlight the safety of FLB-NLC in situ nasal gel and its potential to improve the drug bioavailability and brain delivery.


Assuntos
Benzimidazóis/administração & dosagem , Encéfalo/efeitos dos fármacos , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/química , Nanoestruturas/administração & dosagem , Administração Intranasal , Animais , Benzimidazóis/farmacocinética , Disponibilidade Biológica , Portadores de Fármacos/farmacocinética , Sistemas de Liberação de Medicamentos/métodos , Liberação Controlada de Fármacos , Géis , Lipídeos/administração & dosagem , Lipídeos/química , Masculino , Nanoestruturas/química , Tamanho da Partícula , Polissacarídeos Bacterianos/química , Ratos Wistar , Solubilidade
8.
Chemosphere ; 260: 127639, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32758767

RESUMO

Lipids are biomolecules extracted from plant sources and plant residues and have a beneficial role in various food, nutrition and medical applications. Supercritical carbon-dioxide as an advanced high-pressure technology which increases the productivity and has negligible environmental impact is employed for the selective extraction of polar lipids from the lipid matrix in mango kernel for the first time. The process parameters affecting the extraction such as pressure, temperature and the flow rate of CO2 are ranged in the intervals of 30-50 MPa, 40-60 °C and 10-30 g min-1, respectively. Optimization using Box Behnken design obtained the highest yield of 3.38% at 40 °C, 50 MPa and 30 g min-1. The phosphorous content was evaluated to understand the behaviour of polar lipids extraction at higher pressures. The study showed the effect of process parameters having significant influence on polarity and solvating capacity of CO2 which enabled for the extraction of polar lipids adding value to the mango kernel converting waste into valuable industrial products. The economic evaluation estimates the return on investment of a plant processing 3000 tons of mango kernel per year to account net present value (NPV) almost five times higher than the investment expenses and the payback period is under 4 years.


Assuntos
Dióxido de Carbono/química , Fósforo/química , Cromatografia com Fluido Supercrítico , Análise Custo-Benefício , Lipídeos/química , Mangifera , Extratos Vegetais/química , Temperatura
9.
Int J Nanomedicine ; 15: 5575-5589, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801705

RESUMO

Purpose: The overexpression of Her-2 in 25-30% breast cancer cases and the crosstalk between Her-2 and fatty acid synthase (FASN) establishes Her-2 as a promising target for site-directed delivery. The present study aimed to develop the novel lipid base formulations to target and inhibit the cellular proliferation of Her-2-expressing breast cancer cells through the silencing of FASN. In order to achieve this goal, we prepared DSPC/Chol and DOPE/CHEMS immunoliposomes, conjugated with the anti-Her-2 fab' and encapsulated FASN siRNA against breast cancer cells. Methods: We evaluated the size, stability, cellular uptake and internalization of various formulations of liposomes. The antiproliferative gene silencing potential was investigated by the cell cytotoxicity, crystal violet, wound healing and Western blot analyses in Her-2+ and Her-2¯ breast cancer cells. Results: The data revealed that both nanosized FASN-siRNA-encapsulated liposomes showed significantly higher cellular uptake and internalization with enhanced stability. The cell viability of Her-2+ SK-BR3 cells treated with the targeted formulation of DSPC/Chol- and DOPE/CHEMS-encapsulating FASN-siRNA reduced to 30% and 20%, respectively, whereas it was found to be 45% and 36% in MCF-7 cells. The wounds were not only failed to close but they became broader in Her-2+ cells treated with targeted liposomes of siRNA. Consequently, the amount of FASN decreased by 80% in SK-BR3 cells treated with non-targeted liposomes and it was 30% and 60% in the MCF-7 cells treated with DSPC/Chol and DOPE/CHEMS liposomes, respectively. Conclusion: In this study, we developed the formulation that targeted Her-2 for the suppression of FASN and, therefore, inhibited the proliferation of breast cancer cells.


Assuntos
Neoplasias da Mama/genética , Ácido Graxo Sintase Tipo I/genética , Terapia de Alvo Molecular/métodos , Receptor ErbB-2/metabolismo , Neoplasias da Mama/terapia , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Feminino , Inativação Gênica , Humanos , Concentração de Íons de Hidrogênio , Fragmentos Fab das Imunoglobulinas/química , Lipídeos/química , Lipossomos/administração & dosagem , Lipossomos/química , Lipossomos/imunologia , Células MCF-7 , RNA Interferente Pequeno/genética , Receptor ErbB-2/imunologia
10.
J Chromatogr A ; 1627: 461414, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823112

RESUMO

Various techniques have been evaluated for the extraction and cleanup of pesticides from environmental samples. In this work, a Selective Pressurized Liquid Extraction (SPLE) method for pesticides was developed using a Thermo Fisher Scientific Accelerated Solvent Extraction (ASE) system. This instrument was compared to the newly introduced (2017) extraction instrument, the Energized Dispersive Guided Extraction (EDGE) system, which combines Pressurized Liquid Extraction (PLE) and dispersive Solid Phase Extraction (dSPE). We first optimized the SPLE method using the ASE instrument for pesticide extraction from alfalfa leaves using layers of Florisil and graphitized carbon black (GCB) downstream of the leaf homogenate in the extraction cell (Layered ASE method). We then compared results obtained for alfalfa and citrus leaves with the Layered ASE method to those from a method in which the leaf homogenate and sorbents were mixed (Mixed ASE method) and to similar methods modified for use with EDGE (Layered EDGE and Mixed EDGE methods). The ASE and EDGE methods led to clear, colorless extracts with low residual lipid weight. No significant differences in residual lipid masses were observed between the methods. The UV-Vis spectra showed that Florisil removed a significant quantity of the light-absorbing chemicals, but that GCB was required to produce colorless extracts. Recoveries of spiked analytes into leaf homogenates were generally similar among methods, but in several cases, significantly higher recoveries were observed in ASE extracts. Nonetheless, no significant differences were observed among pesticide concentrations in field samples when calculated with the isotope dilution method in which labelled surrogates were added to samples before extraction. The extraction time with the ASE methods was ~45 minutes, which was ~4.5 times longer than with the EDGE methods. The EDGE methods used ~10 mL more solvent than the ASE methods. Based on these results, the EDGE is an acceptable extraction instrument and, for most compounds, the EDGE had a similar extraction efficiency to the ASE methods.


Assuntos
Técnicas de Química Analítica/métodos , Praguicidas/análise , Folhas de Planta/química , Solventes/química , Lipídeos/química , Medicago sativa/química , Resíduos de Praguicidas/análise , Extratos Vegetais/química , Espectrofotometria Ultravioleta
11.
Arch Insect Biochem Physiol ; 105(1): e21723, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32623787

RESUMO

Insect cuticle lipids are involved in various types of chemical communication between species, and reduce the penetration of insecticides, chemicals, and toxins, as well as provide protection against the attack of microorganisms, parasitic insects, and predators. Ecological studies related to the insect Rhynchophorus palmarum are well-known; however, very little is known about its resistance mechanisms, which includes its lipid composition and its importance, specifically the cuticle layer. This study aimed to characterize the cuticle and internal lipid compounds of the male and female R. palmarum adult insects and to evaluate the presence of antimicrobial activity. We performed by gas chromatography coupled to mass spectrometry (GC-MS) analyzes of lipid extracts fractions and we identified 10 methyl esters of fatty acids esters of C14 to C23, with variation between the sexes of C22:0, C21:0, present only in male cuticle, and C20:2 in female. The lipid content of this insect showed relevant amount of C16:1, C18:1, and C18:2. The antimicrobial activity of the cuticular and internal fractions obtained was tested, which resulted in minimum inhibitory concentrations between 12.5 and 20 µg/ml against Gram-positive bacteria (Staphylococcus epidermidis, Enterococcus faecalis), Gram-negative (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia), and fungal species (Candida albicans e Candida tropicalis). The antimicrobial effect of the R. palmarum cuticle open perspectives for a new source to bioinsecticidal strategies, in addition to elucidating a bioactive mixture against bacteria and fungi.


Assuntos
Anti-Infecciosos/farmacologia , Candida/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Lipídeos/farmacologia , Gorgulhos/química , Animais , Anti-Infecciosos/química , Ésteres/química , Ácidos Graxos/química , Lipídeos/química
12.
Am J Clin Nutr ; 112(3): 683-694, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32710737

RESUMO

BACKGROUND: Small-quantity lipid-based nutrient supplements (SQ-LNS) are efficacious in controlled settings; data are scarce on the effectiveness utilizing health care delivery platforms. OBJECTIVE: We evaluated the impact of an infant young child feeding (IYCF)-SQ-LNS intervention on anemia and growth in children aged 6-18 mo in the Democratic Republic of Congo following a quasi-experimental effectiveness design. METHODS: An intervention health zone (HZ) received enhanced IYCF including improved counseling on IYCF during pregnancy until 12 mo after birth and daily use of SQ-LNS for infants 6-12 mo; the control HZ received the standard IYCF package. We analyzed data from 2995 children, collected in repeated cross-sectional surveys. We used adjusted difference-in-difference analyses to calculate changes in anemia, iron and vitamin A deficiencies, stunting, wasting, and underweight. RESULTS: Of mothers, 70.5% received SQ-LNS at least once in the intervention HZ, with 99.6% of their children consuming SQ-LNS at least once. The mean number of batches of SQ-LNS (28 sachets per batch, 6 batches total) received was 2.3 ± 0.8 (i.e., 64.4 ± 22.4 d of SQ-LNS). The enhanced program was associated with an 11.0% point (95% CI: -18.1, -3.8; P < 0.01) adjusted relative reduction in anemia prevalence and a mean +0.26-g/dL (95% CI: 0.04, 0.48; P = 0.02) increase in hemoglobin but no effect on anthropometry or iron or vitamin A deficiencies. At endline in the intervention HZ, children aged 8-13 mo who received ≥3 monthly SQ-LNS batch distributions had higher anthropometry z scores [length-for-age z score (LAZ): +0.40, P = 0.04; weight-for-age z score (WAZ): +0.37, P = 0.04] and hemoglobin (+0.65 g/dL, P = 0.007) and a lower adjusted prevalence difference of stunting (-16.7%, P = 0.03) compared with those who received none. CONCLUSIONS: The enhanced IYCF-SQ-LNS intervention using the existing health care delivery platform was associated with a reduction in prevalence of anemia and improvement in mean hemoglobin. At endline among the subpopulation receiving ≥3 mo of SQ-LNS, their LAZ, WAZ, and hemoglobin improved. Future research could explore contextual tools to maximize coverage and intake adherence in programs using SQ-LNS.


Assuntos
Anemia/epidemiologia , Anemia/prevenção & controle , Desenvolvimento Infantil/efeitos dos fármacos , Suplementos Nutricionais , Lipídeos/química , República Democrática do Congo/epidemiologia , Transtornos do Crescimento/prevenção & controle , Humanos , Lactente , Lipídeos/administração & dosagem
13.
J Chromatogr A ; 1625: 461233, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709312

RESUMO

Untargeted metabolomics can be a great tool for exploring new scientific areas; however, wrong metabolite annotation questions the credibility and puts the success of the entire research at risk. Therefore, an effort should be made to improve the quality and robustness of the annotation despite of the challenges, especially when final identification with standards is not possible. Through non-targeted analysis of human plasma samples, from a large cancer cohort study using RP-LC-ESI-QTOF-MS/MS, we have resolved MS/MS annotation through spectral matching, directed to hydroxyeicosatetraenoic acids (HETEs) and, MS/MS structural elucidation for newly annotated oxidized lyso-phosphatidylcholines (oxLPCs). The annotation of unknowns is supported with structural information from fragmentation spectra as well as the fragmentation mechanisms involved, necessarily including data from both polarity modes and different collision energies. In this work, we present evidences that various oxidation products show significant differences between cancer patients and control individuals and we establish a workflow to help identify such modifications. We report here the upregulation of HETEs and oxLPCs in patients with neuroendocrine tumors (NETs). To our knowledge, this is the first attempt to determine HETEs in NETs and one of very few studies where oxLPCs are annotated. The obtained results provide an important insight regarding lipid oxidation in NETs, although their physiological functions still have to be established and require further research.


Assuntos
Lipídeos/sangue , Metaboloma , Adulto , Idoso , Idoso de 80 Anos ou mais , Axitinibe/uso terapêutico , Cromatografia Líquida de Alta Pressão , Cromatografia de Fase Reversa , Feminino , Humanos , Peroxidação de Lipídeos , Lipídeos/química , Lipídeos/isolamento & purificação , Lisofosfatidilcolinas/sangue , Lisofosfatidilcolinas/química , Lisofosfatidilcolinas/isolamento & purificação , Masculino , Pessoa de Meia-Idade , Tumores Neuroendócrinos/tratamento farmacológico , Tumores Neuroendócrinos/metabolismo , Tumores Neuroendócrinos/patologia , Análise de Componente Principal , Espectrometria de Massas em Tandem/métodos
14.
Nat Commun ; 11(1): 3752, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32719334

RESUMO

Glycinergic synapses play a central role in motor control and pain processing in the central nervous system. Glycine receptors (GlyRs) are key players in mediating fast inhibitory neurotransmission at these synapses. While previous high-resolution structures have provided insights into the molecular architecture of GlyR, several mechanistic questions pertaining to channel function are still unanswered. Here, we present Cryo-EM structures of the full-length GlyR protein complex reconstituted into lipid nanodiscs that are captured in the unliganded (closed), glycine-bound (open and desensitized), and allosteric modulator-bound conformations. A comparison of these states reveals global conformational changes underlying GlyR channel gating and modulation. The functional state assignments were validated by molecular dynamics simulations, and the observed permeation events are in agreement with the anion selectivity and conductance of GlyR. These studies provide the structural basis for gating, ion selectivity, and single-channel conductance properties of GlyR in a lipid environment.


Assuntos
Ativação do Canal Iônico , Lipídeos/química , Nanopartículas/química , Receptores da Glicina/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Regulação Alostérica , Animais , Sítios de Ligação , Glicina/metabolismo , Simulação de Dinâmica Molecular , Neurotransmissores/metabolismo , Conformação Proteica , Receptores da Glicina/ultraestrutura , Xenopus , Proteínas de Peixe-Zebra/ultraestrutura
15.
Sci Transl Med ; 12(555)2020 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-32690628

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic, caused by infection with the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), is having a deleterious impact on health services and the global economy, highlighting the urgent need for an effective vaccine. Such a vaccine would need to rapidly confer protection after one or two doses and would need to be manufactured using components suitable for scale up. Here, we developed an Alphavirus-derived replicon RNA vaccine candidate, repRNA-CoV2S, encoding the SARS-CoV-2 spike (S) protein. The RNA replicons were formulated with lipid inorganic nanoparticles (LIONs) that were designed to enhance vaccine stability, delivery, and immunogenicity. We show that a single intramuscular injection of the LION/repRNA-CoV2S vaccine in mice elicited robust production of anti-SARS-CoV-2 S protein IgG antibody isotypes indicative of a type 1 T helper cell response. A prime/boost regimen induced potent T cell responses in mice including antigen-specific responses in the lung and spleen. Prime-only immunization of aged (17 months old) mice induced smaller immune responses compared to young mice, but this difference was abrogated by booster immunization. In nonhuman primates, prime-only immunization in one intramuscular injection site or prime/boost immunizations in five intramuscular injection sites elicited modest T cell responses and robust antibody responses. The antibody responses persisted for at least 70 days and neutralized SARS-CoV-2 at titers comparable to those in human serum samples collected from individuals convalescing from COVID-19. These data support further development of LION/repRNA-CoV2S as a vaccine candidate for prophylactic protection against SARS-CoV-2 infection.


Assuntos
Alphavirus/genética , Anticorpos Neutralizantes/imunologia , Betacoronavirus/imunologia , Infecções por Coronavirus/imunologia , Pneumonia Viral/imunologia , RNA Viral/genética , Replicon/genética , Linfócitos T/imunologia , Vacinas Virais/imunologia , Animais , Formação de Anticorpos/imunologia , Infecções por Coronavirus/prevenção & controle , Compostos Inorgânicos/química , Lipídeos/química , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Nanopartículas/química , Pandemias , Primatas
16.
Int J Nanomedicine ; 15: 4091-4104, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606666

RESUMO

Introduction: Humans are intentionally exposed to gold nanoparticles (AuNPs) where they are used in variety of biomedical applications as imaging and drug delivery agents as well as diagnostic and therapeutic agents currently in clinic and in a variety of upcoming clinical trials. Consequently, it is critical that we gain a better understanding of how physiochemical properties such as size, shape, and surface chemistry drive cellular uptake and AuNP toxicity in vivo. Understanding and being able to manipulate these physiochemical properties will allow for the production of safer and more efficacious use of AuNPs in biomedical applications. Methods and Materials: Here, AuNPs of three sizes, 5 nm, 10 nm, and 20 nm, were coated with a lipid bilayer composed of sodium oleate, hydrogenated phosphatidylcholine, and hexanethiol. To understand how the physical features of AuNPs influence uptake through cellular membranes, sum frequency generation (SFG) was utilized to assess the interactions of the AuNPs with a biomimetic lipid monolayer composed of a deuterated phospholipid 1.2-dipalmitoyl-d62-sn-glycero-3-phosphocholine (dDPPC). Results and Discussion: SFG measurements showed that 5 nm and 10 nm AuNPs are able to phase into the lipid monolayer with very little energetic cost, whereas, the 20 nm AuNPs warped the membrane conforming it to the curvature of hybrid lipid-coated AuNPs. Toxicity of the AuNPs were assessed in vivo to determine how AuNP curvature and uptake influence cell health. In contrast, in vivo toxicity tested in embryonic zebrafish showed rapid toxicity of the 5 nm AuNPs, with significant 24 hpf mortality occurring at concentrations ≥20 mg/L, whereas the 10 nm and 20 nm AuNPs showed no significant mortality throughout the five-day experiment. Conclusion: By combining information from membrane models using SFG spectroscopy with in vivo toxicity studies, a better mechanistic understanding of how nanoparticles (NPs) interact with membranes is developed to understand how the physiochemical features of AuNPs drive nanoparticle-membrane interactions, cellular uptake, and toxicity.


Assuntos
Membrana Celular/química , Ouro/toxicidade , Lipídeos/química , Membranas Artificiais , Nanopartículas Metálicas/toxicidade , Tamanho da Partícula , Testes de Toxicidade , Animais , Embrião não Mamífero/anormalidades , Embrião não Mamífero/efeitos dos fármacos , Humanos , Espectrofotometria Ultravioleta , Análise Espectral , Peixe-Zebra/embriologia
17.
Nature ; 585(7823): 85-90, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32699409

RESUMO

A relatively small number of proteins have been suggested to act as morphogens-signalling molecules that spread within tissues to organize tissue repair and the specification of cell fate during development. Among them are Wnt proteins, which carry a palmitoleate moiety that is essential for signalling activity1-3. How a hydrophobic lipoprotein can spread in the aqueous extracellular space is unknown. Several mechanisms, such as those involving lipoprotein particles, exosomes or a specific chaperone, have been proposed to overcome this so-called Wnt solubility problem4-6. Here we provide evidence against these models and show that the Wnt lipid is shielded by the core domain of a subclass of glypicans defined by the Dally-like protein (Dlp). Structural analysis shows that, in the presence of palmitoleoylated peptides, these glypicans change conformation to create a hydrophobic space. Thus, glypicans of the Dlp family protect the lipid of Wnt proteins from the aqueous environment and serve as a reservoir from which Wnt proteins can be handed over to signalling receptors.


Assuntos
Glipicanas/química , Glipicanas/metabolismo , Lipídeos , Transdução de Sinais , Proteínas Wnt/química , Proteínas Wnt/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/química , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/metabolismo , Proteínas de Drosophila/química , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Ácidos Graxos Monoinsaturados/química , Ácidos Graxos Monoinsaturados/metabolismo , Feminino , Glipicanas/classificação , Humanos , Interações Hidrofóbicas e Hidrofílicas , Lipídeos/química , Masculino , Modelos Moleculares , Mutação , Proteínas Nucleares/química , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Ligação Proteica/genética , Domínios Proteicos , Transporte Proteico , Solubilidade , Proteína Wnt1/química , Proteína Wnt1/metabolismo
18.
Nat Commun ; 11(1): 3396, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32636380

RESUMO

Arabinosyltransferase B (EmbB) belongs to a family of membrane-bound glycosyltransferases that build the lipidated polysaccharides of the mycobacterial cell envelope, and are targets of anti-tuberculosis drug ethambutol. We present the 3.3 Å resolution single-particle cryo-electron microscopy structure of Mycobacterium smegmatis EmbB, providing insights on substrate binding and reaction mechanism. Mutations that confer ethambutol resistance map mostly around the putative active site, suggesting this to be the location of drug binding.


Assuntos
Mycobacterium smegmatis/enzimologia , Pentosiltransferases/química , Pentosiltransferases/ultraestrutura , Antituberculosos/farmacologia , Domínio Catalítico , Microscopia Crioeletrônica , Farmacorresistência Bacteriana , Etambutol/farmacologia , Lipídeos/química , Mutação , Mycobacterium tuberculosis/enzimologia , Polissacarídeos/química , Ligação Proteica
19.
Food Chem ; 333: 127509, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32717715

RESUMO

Due to their antioxidant properties, polyphenols are finding novel applications in the fields of Food Technology and Functional Nutrition in the development of innovative functional food products, and in Cosmetics and Regenerative Medicine in the development of formulations for skin disorders. The added-value of polyphenols in these areas is intimately linked to the health benefits they induce which in turn is related to the permeability across the epithelial membrane, a parameter obtained through biomimetic models. This work overviews the knowledge on the interactions of polyphenols with membrane lipids in in vitro models and the underlying challenges in translating biophysical changes achieved with current oversimplified membrane models highlighting the need for improved epithelial membrane models and in turn a better knowledge of the epithelial lipidome. Improved insight into the polyphenol-lipid interactions in vivo (patho)physiological processes will open new opportunities for the exploitation of Food and Agro-Food waste products in Health-related areas.


Assuntos
Lipidômica , Lipídeos/química , Lipídeos de Membrana/química , Polifenóis/química , Animais , Biomimética , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Humanos , Fluidez de Membrana
20.
PLoS One ; 15(7): e0236106, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32673362

RESUMO

Alfalfa is a forage legume commonly associated with ruminant livestock production that may be a potential source of health-promoting phytochemicals. Anecdotal evidence from producers suggests that later cuttings of alfalfa may be more beneficial to non-ruminants; however, published literature varies greatly in measured outcomes, supplement form, and cutting. The objective of this study was to measure body weight, average daily feed intake, host immunity, and the colon microbiota composition in mice fed hay, aqueous, and chloroform extracts of early (1st) and late (5th) cutting alfalfa before and after challenge with Citrobacter rodentium. Prior to inoculation, alfalfa supplementation did not have a significant impact on body weight or feed intake, but 5th cutting alfalfa was shown to improve body weight at 5- and 6-days post-infection compared to 1st cutting alfalfa (P = 0.02 and 0.01). Combined with the observation that both chloroform extracts improved mouse body weight compared to control diets in later stages of C. rodentium infection led to detailed analyses of the immune system and colon microbiota in mice fed 1st and 5th cutting chloroform extracts. Immediately following inoculation, 5th cutting chloroform extracts significantly reduced the relative abundance of C. rodentium (P = 0.02) and did not display the early lymphocyte recruitment observed in 1st cutting extract. In later timepoints, both chloroform extracts maintained lower splenic B-cell and macrophage populations while increasing the relative abundance of potentially beneficially genera such as Turicibacter (P = 0.02). At 21dpi, only 5th cutting chloroform extracts increased the relative abundance of beneficial Akkermansia compared to the control diet (P = 0.02). These results suggest that lipid soluble compounds enriched in late-cutting alfalfa modulate pathogen colonization and early immune responses to Citrobacter rodentium, contributing to protective effects on body weight.


Assuntos
Citrobacter rodentium/fisiologia , Colo/efeitos dos fármacos , Infecções por Enterobacteriaceae/tratamento farmacológico , Microbioma Gastrointestinal/efeitos dos fármacos , Lipídeos/química , Medicago sativa/química , Extratos Vegetais/farmacologia , Imunidade Adaptativa/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Colo/microbiologia , Citocinas/biossíntese , Infecções por Enterobacteriaceae/imunologia , Infecções por Enterobacteriaceae/metabolismo , Infecções por Enterobacteriaceae/microbiologia , Feminino , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Interações Hospedeiro-Patógeno/imunologia , Imunidade Inata/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Extratos Vegetais/uso terapêutico , Solubilidade
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