Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33.610
Filtrar
1.
Analyst ; 146(23): 7257-7264, 2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34734932

RESUMO

Here, an Au-Cu dual-electrode tip was designed to monitor the effect of Cu2+ on the membrane permeability of a single living cell in situ using scanning electrochemical microscopy. The probe approach curves (PACs) were obtained using potassium ferricyanide as a redox mediator. Meanwhile, according to the simulation, theoretical PACs could be acquired. Thus, the cell membrane permeability coefficient (Pm) values were obtained by overlapping the experimental PACs with the theoretical values. Cu2+ was directly generated by electrolyzing the Cu electrode of the dual-electrode tip to investigate its effect on the cell membrane permeability in situ. This work has potential value to improve the understanding of the mechanism of acute heavy metal damage on the cell membrane and will also help clarify the role of heavy metal ions in physiological or pathological processes.


Assuntos
Microscopia Eletroquímica de Varredura , Permeabilidade da Membrana Celular , Eletrodos , Oxirredução , Permeabilidade
2.
Science ; 374(6568): eabe6723, 2021 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-34735226

RESUMO

A diverse group of antimicrobial proteins (AMPs) helps protect the mammalian intestine from varied microbial challenges. We show that small proline-rich protein 2A (SPRR2A) is an intestinal antibacterial protein that is phylogenetically unrelated to previously discovered mammalian AMPs. In this study, SPRR2A was expressed in Paneth cells and goblet cells and selectively killed Gram-positive bacteria by disrupting their membranes. SPRR2A shaped intestinal microbiota composition, restricted bacterial association with the intestinal surface, and protected against Listeria monocytogenes infection. SPRR2A differed from other intestinal AMPs in that it was induced by type 2 cytokines produced during helminth infection. Moreover, SPRR2A protected against helminth-induced bacterial invasion of intestinal tissue. Thus, SPRR2A is a distinctive AMP triggered by type 2 immunity that protects the intestinal barrier during helminth infection.


Assuntos
Proteínas Ricas em Prolina do Estrato Córneo/metabolismo , Microbioma Gastrointestinal , Bactérias Gram-Positivas/fisiologia , Mucosa Intestinal/metabolismo , Intestinos/microbiologia , Nematospiroides dubius , Infecções por Strongylida/imunologia , Animais , Carga Bacteriana , Membrana Celular/metabolismo , Permeabilidade da Membrana Celular , Proteínas Ricas em Prolina do Estrato Córneo/genética , Citocinas/metabolismo , Suscetibilidade a Doenças , Células Caliciformes/metabolismo , Humanos , Imunidade Inata , Mucosa Intestinal/microbiologia , Listeria monocytogenes/fisiologia , Listeriose/microbiologia , Camundongos , Viabilidade Microbiana , Celulas de Paneth/metabolismo , Proteínas Citotóxicas Formadoras de Poros/genética , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Infecções por Strongylida/metabolismo , Infecções por Strongylida/microbiologia
3.
Int J Mol Sci ; 22(19)2021 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-34639101

RESUMO

A well-functional intestinal mucosal barrier can be compromised as a result of various diseases, chemotherapy, radiation, and chemical exposures including surfactants. Currently, there are no approved drugs targeting a dysfunctional intestinal barrier, which emphasizes a significant medical need. One candidate drug reported to regulate intestinal mucosal permeability is melatonin. However, it is still unclear if its effect is primarily receptor mediated or antioxidative, and if it is associated with enteric neural pathways. The aim of this rat intestinal perfusion study was to investigate the mechanisms of melatonin and nicotinic acetylcholine receptors on the increase in intestinal mucosal clearance of 51Cr-labeled ethylenediaminetetraacetate induced by 15 min luminal exposure to the anionic surfactant, sodium dodecyl sulfate. Our results show that melatonin abolished the surfactant-induced increase in intestinal permeability and that this effect was inhibited by luzindole, a melatonin receptor antagonist. In addition, mecamylamine, an antagonist of nicotinic acetylcholine receptors, reduced the surfactant-induced increase in mucosal permeability, using a signaling pathway not influenced by melatonin receptor activation. In conclusion, our results support melatonin as a potentially potent candidate for the oral treatment of a compromised intestinal mucosal barrier, and that its protective effect is primarily receptor-mediated.


Assuntos
Permeabilidade da Membrana Celular , Mucosa Intestinal/efeitos dos fármacos , Doenças do Jejuno/prevenção & controle , Jejuno/efeitos dos fármacos , Melatonina/farmacologia , Receptores de Melatonina/metabolismo , Tensoativos/toxicidade , Animais , Antioxidantes/farmacologia , Motilidade Gastrointestinal , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Doenças do Jejuno/induzido quimicamente , Doenças do Jejuno/metabolismo , Doenças do Jejuno/patologia , Jejuno/metabolismo , Jejuno/patologia , Masculino , Ratos , Ratos Wistar , Receptores de Melatonina/genética , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo
4.
Int J Mol Sci ; 22(19)2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34639182

RESUMO

The skin barrier is broadly composed of two elements-a physical barrier mostly localised in the epidermis, and an immune barrier localised in both the dermis and epidermis. These two systems interact cooperatively to maintain skin homeostasis and overall human health. However, if dysregulated, several skin diseases may arise. Psoriasis is one of the most prevalent skin diseases associated with disrupted barrier function. It is characterised by the formation of psoriatic lesions, the aberrant differentiation and proliferation of keratinocytes, and excessive inflammation. In this review, we summarize recent discoveries in disease pathogenesis, including the contribution of keratinocytes, immune cells, genetic and environmental factors, and how they advance current and future treatments.


Assuntos
Permeabilidade da Membrana Celular , Psoríase/patologia , Pele/patologia , Humanos , Psoríase/etiologia , Fenômenos Fisiológicos da Pele
5.
Int J Mol Sci ; 22(19)2021 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-34639049

RESUMO

The ability of sodium caprylate and l-menthol to fluidize phospholipid bilayers composed of lipids simulating the buccal epithelium was investigated using electron spin resonance (ESR) to evaluate the action of these agents as permeation enhancers. 5-Doxyl stearic acid (5-DSA) and 16-doxyl stearic acid (16-DSA) were used as spin labels to identify alterations in membrane fluidity near the polar head groups or inner acyl regions of the lipid bilayer, respectively. The molecular motion of both 5-DSA and 16-DSA showed increased disorder near the polar and inner hydrophobic regions of the bilayer in the presence of sodium caprylate suggesting fluidization in both the regions, which contributes to its permeation enhancing effects. L-menthol decreased the order parameter for 16-DSA, showing membrane fluidization only in the inner acyl regions of the bilayer, which also corresponded to its weaker permeation enhancing effects. The rapid evaluation of changes in fluidity of the bilayer in the presence of potential permeation enhancers using ESR enables improved selection of effective permeation enhancers and enhancer combinations based on their effect on membrane fluidization.


Assuntos
Caprilatos/farmacologia , Espectroscopia de Ressonância de Spin Eletrônica , Fluidez de Membrana/efeitos dos fármacos , Mentol/farmacologia , Mucosa Bucal/efeitos dos fármacos , Mucosa Bucal/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Óxidos N-Cíclicos/química , Óxidos N-Cíclicos/farmacologia , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Bicamadas Lipídicas , Lipossomos , Lipídeos de Membrana/química , Lipídeos de Membrana/metabolismo , Fosfolipídeos/química , Fosfolipídeos/metabolismo
6.
Nat Commun ; 12(1): 6074, 2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34667173

RESUMO

Mechanosensitive (MS) ion channels respond to mechanical stress and convert it into intracellular electric and ionic signals. Five MS channel families have been identified in plants, including the Mid1-Complementing Activity (MCA) channel; however, its activation mechanisms have not been elucidated in detail. We herein demonstrate that the MCA2 channel is a Ca2+-permeable MS channel that is directly activated by membrane tension. The N-terminal 173 residues of MCA1 and MCA2 were synthesized in vitro, purified, and reconstituted into artificial liposomal membranes. Liposomes reconstituted with MCA1(1-173) or MCA2(1-173) mediate Ca2+ influx and the application of pressure to the membrane reconstituted with MCA2(1-173) elicits channel currents. This channel is also activated by voltage. Blockers for MS channels inhibit activation by stretch, but not by voltage. Since MCA proteins are found exclusively in plants, these results suggest that MCA represent plant-specific MS channels that open directly with membrane tension.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Cálcio/metabolismo , Membrana Celular/metabolismo , Mecanotransdução Celular , Proteínas de Membrana/metabolismo , Arabidopsis/química , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Transporte Biológico , Membrana Celular/química , Membrana Celular/genética , Permeabilidade da Membrana Celular , Proteínas de Membrana/genética
7.
PLoS One ; 16(10): e0258275, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34618865

RESUMO

In addition to the classical voltage-dependent behavior mediated by the voltage-sensing-domains (VSD) of ion channels, a growing number of voltage-dependent gating behaviors are being described in channels that lack canonical VSDs. A common thread in their mechanism of action is the contribution of the permeating ion to this voltage sensing process. The polymodal K2P K+ channel, TREK2 responds to membrane voltage through a gating process mediated by the interaction of K+ with its selectivity filter. Recently, we found that this action can be modulated by small molecule agonists (e.g. BL1249) which appear to have an electrostatic influence on K+ binding within the inner cavity and produce an increase in the single-channel conductance of TREK-2 channels. Here, we directly probed this K+-dependent gating process by recording both macroscopic and single-channel currents of TREK-2 in the presence of high concentrations of internal K+. Surprisingly we found TREK-2 is inhibited by high internal K+ concentrations and that this is mediated by the concomitant increase in ionic-strength. However, we were still able to determine that the increase in single channel conductance in the presence of BL1249 was blunted in high ionic-strength, whilst its activatory effect (on channel open probability) persisted. These effects are consistent with an electrostatic mechanism of action of negatively charged activators such as BL1249 on permeation, but also suggest that their influence on channel gating is complex.


Assuntos
Permeabilidade da Membrana Celular , Ativação do Canal Iônico , Concentração Osmolar , Canais de Potássio de Domínios Poros em Tandem/metabolismo , Ânions , Células HEK293 , Humanos , Pressão Osmótica , Conformação Proteica
8.
Int J Mol Sci ; 22(17)2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-34502292

RESUMO

This is an attempt to make readers of the second edition of International Journal of Molecular Sciences Special Issue on the Barrier Function of Skin and Oral Mucosa aware of the content of the first edition on this same topic [...].


Assuntos
Permeabilidade da Membrana Celular , Mucosa Bucal/fisiologia , Pele/metabolismo , Humanos
9.
Analyst ; 146(19): 5973-5979, 2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34499067

RESUMO

Cell membrane permeability is one of the main indicators of cytotoxicity and related to many critical biological pathways. Here, we determined the Cd2+-induced membrane permeability of human MCF-7 cells using ferrocene methanol molecular probes based on scanning electrochemical microscopy (SECM). The cell height and topography were examined with an impermeable Ru(NH3)6Cl3 probe. The membrane permeability exhibited no significant changes when the Cd2+ incubation time was less than 2 h and its concentration was less than 40 µM. The permeability increased when the Cd2+ concentration was greater than 60 µM, or when the incubation time was longer than 3 h. From the combined 3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and cytoskeleton imaging experiments, it was found that the changes occurred because the cells exhibited a defensive mode and their membranes contracted when treated with a low concentration of Cd2+ for a short time. However, the cell membranes were irreversibly damaged when the cytoskeleton structures were destroyed, and the cell activities decreased at high concentrations over long periods. Interestingly, through the comparison with an x-scan study, it was found that DPV technology shows a higher performance in the detection of changes in the membrane permeability. Using a combination of cytoskeleton fluorescence imaging and cell-viability tests, the effect of the cadmium metal on the cell membrane permeability can be explored deeper and more comprehensively. This study provides a new idea for exploring the changes in the cell membrane permeability and may be helpful for rapid evaluation of cytotoxicity.


Assuntos
Cádmio , Cádmio/toxicidade , Permeabilidade da Membrana Celular , Sobrevivência Celular , Humanos , Microscopia Eletroquímica de Varredura , Permeabilidade
10.
Invest Ophthalmol Vis Sci ; 62(12): 17, 2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34542556

RESUMO

Purpose: Investigate the contribution of the Wnt pathway to vascular endothelial growth factor (VEGF)/anti-VEGF-mediated control of endothelial cell permeability. Methods: High glucose-treated primary human retinal endothelial cells (HRECs) were exposed to either VEGF, or VEGF and then anti-VEGF. Changes in gene expression were assayed by RNAseq and qRT-PCR. Permeability was monitored by electrical cell-substrate impedance sensing (ECIS). Approaches to activate the Wnt pathway included treatment with LiCl and overexpression of constitutively activated ß-catenin. ß-catenin-dependent transcriptional activity was monitored in HRECs stably expressing a TCF/LEF-driven reporter. Results: VEGF/anti-VEGF altered expression of genes encoding many members of the Wnt pathway. A subset of these genes was regulated in a way that is likely to contribute to control of the endothelial cell barrier. Namely, the VEGF-induced alteration of expression of such genes was reversed by anti-VEGF, and such adjustments occurred at times corresponding to changes in barrier function. While pharmacological and molecular approaches to activate the Wnt pathway had no effect on basal permeability, they suppressed VEGF-induced relaxation. Furthermore, anti-VEGF-mediated restoration of barrier function was unaffected by activation of the Wnt pathway. Conclusions: VEGF/anti-VEGF engages multiple members of the Wnt pathway, and activating this pathway enforces the endothelial barrier by attenuating VEGF-induced relaxation. These data suggest that FDA-approved agents such as LiCl may be an adjuvant to anti-VEGF therapy for patients afflicted with blinding conditions including diabetic retinopathy.


Assuntos
Permeabilidade da Membrana Celular/fisiologia , Células Endoteliais/metabolismo , Vasos Retinianos/citologia , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Fator A de Crescimento do Endotélio Vascular/metabolismo , Via de Sinalização Wnt/fisiologia , Adulto , Inibidores da Angiogênese/farmacologia , Células Cultivadas , Impedância Elétrica , Regulação da Expressão Gênica/fisiologia , Glucose/farmacologia , Humanos , Lentivirus/genética , Cloreto de Lítio/farmacologia , Masculino , Reação em Cadeia da Polimerase em Tempo Real , Receptores de Fatores de Crescimento do Endotélio Vascular , Proteínas Recombinantes de Fusão/farmacologia , Transfecção , beta Catenina/metabolismo
11.
Int J Mol Sci ; 22(18)2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34576076

RESUMO

Mesenteric ischemia and reperfusion (I/R) injury can ensue from a variety of vascular diseases and represents a major cause of morbidity and mortality in intensive care units. It causes an inflammatory response associated with local gut dysfunction and remote organ injury. Adenosine monophosphate-activated protein kinase (AMPK) is a crucial regulator of metabolic homeostasis. The catalytic α1 subunit is highly expressed in the intestine and vascular system. In loss-of-function studies, we investigated the biological role of AMPKα1 in affecting the gastrointestinal barrier function. Male knock-out (KO) mice with a systemic deficiency of AMPKα1 and wild-type (WT) mice were subjected to a 30 min occlusion of the superior mesenteric artery. Four hours after reperfusion, AMPKα1 KO mice exhibited exaggerated histological gut injury and impairment of intestinal permeability associated with marked tissue lipid peroxidation and a lower apical expression of the junction proteins occludin and E-cadherin when compared to WT mice. Lung injury with neutrophil sequestration was higher in AMPKα1 KO mice than WT mice and paralleled with higher plasma levels of syndecan-1, a biomarker of endothelial injury. Thus, the data demonstrate that AMPKα1 is an important requisite for epithelial and endothelial integrity and has a protective role in remote organ injury after acute ischemic events.


Assuntos
Proteínas Quinases Ativadas por AMP/deficiência , Lesão Pulmonar Aguda/complicações , Intestinos/enzimologia , Intestinos/lesões , Isquemia Mesentérica/complicações , Traumatismo por Reperfusão/complicações , Proteínas Quinases Ativadas por AMP/genética , Lesão Pulmonar Aguda/enzimologia , Animais , Caderinas/metabolismo , Permeabilidade da Membrana Celular , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Células Epiteliais/metabolismo , Glicocálix/metabolismo , Intestinos/patologia , Isquemia Mesentérica/enzimologia , Camundongos Endogâmicos C57BL , Ocludina/metabolismo , Traumatismo por Reperfusão/enzimologia
12.
Chem Biol Interact ; 349: 109661, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34537181

RESUMO

Phytochemical analysis of EtOH extract from leaves of Nectandra oppositifolia afforded three flavonoids: kaempferol (1), kaempferol-3-O-α-rhamnopyranoside (2) and kaempferol-3-O-α-(3,4-di-E-p-coumaroyl)-rhamnopyranoside (3), which were characterized by NMR and ESI-HRMS. When tested against the protozoan parasite Trypanosoma cruzi, the etiologic agent of Chagas disease, flavonoids 1 and 3 were effective to kill the trypomastigotes with IC50 values of 32.0 and 6.7 µM, respectively, while flavonoid 2 was inactive. Isolated flavonoids 1-3 were also tested in mammalian fibroblasts and showed CC50 values of 24.8, 48.7 and 153.1 µM, respectively. Chemically, these results suggested that the free aglycone plays an important role in the bioactivity while the presence of p-coumaroyl unities linked in the rhamnoside unity is important to enhance the antitrypanosomal activity and reduce the mammalian cytotoxicity. The mechanism of cellular death was investigated for the most potent flavonoid 3 in the trypomastigotes using fluorescent and luminescent-based assays. It indicated that this compound induced neither permeabilization of the plasma membrane nor depolarization of the membrane electric potential. However, early time incubation (20 min) with flavonoid 3 resulted in a constant elevation of the Ca2+ levels inside the parasite. This effect was followed by a mitochondrial imbalance, leading to a hyperpolarization and depolarization of the mitochondrial membrane potential, with reduction of the ATP levels. During this time, the levels of reactive oxygen species levels (ROS) were unaltered. The leakage of Ca2+ from the intracellular pools can affect the bioenergetics system of T. cruzi, leading to the parasite death. Therefore, flavonoid 3 can be a useful tool for future studies against T. cruzi parasites.


Assuntos
Cálcio/metabolismo , Flavonoides/química , Quempferóis/química , Lauraceae/química , Trypanosoma cruzi/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Permeabilidade da Membrana Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Feminino , Flavonoides/isolamento & purificação , Flavonoides/farmacologia , Íons/química , Lauraceae/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Extratos Vegetais/química , Folhas de Planta/química , Folhas de Planta/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Trypanosoma cruzi/efeitos dos fármacos
13.
Lab Chip ; 21(20): 4005-4015, 2021 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-34476431

RESUMO

Rapid and personalized single-cell drug screening testing plays an essential role in acute myeloid leukemia drug combination chemotherapy. Conventional chemotherapeutic drug screening is a time-consuming process because of the natural resistance of cell membranes to drugs, and there are still great challenges related to using technologies that change membrane permeability such as sonoporation in high-throughput and precise single-cell drug screening with minimal damage. In this study, we proposed an acoustic streaming-based non-invasive single-cell drug screening acceleration method, using high-frequency acoustic waves (>10 MHz) in a concentration gradient microfluidic device. High-frequency acoustics leads to increased difficulties in inducing cavitation and generates acoustic streaming around each single cell. Therefore, single-cell membrane permeability is non-invasively increased by the acoustic pressure and acoustic streaming-induced shear force, which significantly improves the drug uptake process. In the experiment, single human myeloid leukemia mononuclear (THP-1) cells were trapped by triangle cell traps in concentration gradient chips with different cytarabine (Ara-C) drug concentrations. Due to this dual acoustic effect, the drugs affect cell viability in less than 30 min, which is faster than traditional methods (usually more than 24 h). This dual acoustic effect-based drug delivery strategy has the potential to save time and reduce the cost of drug screening, when combined with microfluidic technology for multi-concentration drug screening. This strategy offers enormous potential for use in multiple drug screening or efficient drug combination screening in individualized/personalized treatments, which can greatly improve efficiency and reduce costs.


Assuntos
Acústica , Leucemia Mieloide Aguda , Permeabilidade da Membrana Celular , Sobrevivência Celular , Avaliação Pré-Clínica de Medicamentos , Humanos
14.
Molecules ; 26(17)2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-34500849

RESUMO

Peptide-oligonucleotide conjugates (POCs) represent one of the increasingly successful albeit costly approaches to increasing the cellular uptake, tissue delivery, bioavailability, and, thus, overall efficiency of therapeutic nucleic acids, such as, antisense oligonucleotides and small interfering RNAs. This review puts the subject of chemical synthesis of POCs into the wider context of therapeutic oligonucleotides and the problem of nucleic acid drug delivery, cell-penetrating peptide structural types, the mechanisms of their intracellular transport, and the ways of application, which include the formation of non-covalent complexes with oligonucleotides (peptide additives) or covalent conjugation. The main strategies for the synthesis of POCs are viewed in detail, which are conceptually divided into (a) the stepwise solid-phase synthesis approach and (b) post-synthetic conjugation either in solution or on the solid phase, especially by means of various click chemistries. The relative advantages and disadvantages of both strategies are discussed and compared.


Assuntos
Peptídeos Penetradores de Células/química , Preparações de Ação Retardada/química , Oligonucleotídeos/química , Sequência de Aminoácidos , Sistemas CRISPR-Cas , Permeabilidade da Membrana Celular , Peptídeos Penetradores de Células/metabolismo , Química Click , Liberação Controlada de Fármacos , Humanos , Ácidos Nucleicos , Oligonucleotídeos/metabolismo , RNA Interferente Pequeno/química , Técnicas de Síntese em Fase Sólida
15.
Nat Commun ; 12(1): 4743, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34362911

RESUMO

Biology has evolved a variety of agents capable of permeabilizing and disrupting lipid membranes, from amyloid aggregates, to antimicrobial peptides, to venom compounds. While often associated with disease or toxicity, these agents are also central to many biosensing and therapeutic technologies. Here, we introduce a class of synthetic, DNA-based particles capable of disrupting lipid membranes. The particles have finely programmable size, and self-assemble from all-DNA and cholesterol-DNA nanostructures, the latter forming a membrane-adhesive core and the former a protective hydrophilic corona. We show that the corona can be selectively displaced with a molecular cue, exposing the 'sticky' core. Unprotected particles adhere to synthetic lipid vesicles, which in turn enhances membrane permeability and leads to vesicle collapse. Furthermore, particle-particle coalescence leads to the formation of gel-like DNA aggregates that envelop surviving vesicles. This response is reminiscent of pathogen immobilisation through immune cells secretion of DNA networks, as we demonstrate by trapping E. coli bacteria.


Assuntos
Bactérias/metabolismo , DNA/química , Lipídeos de Membrana/química , Permeabilidade da Membrana Celular , Escherichia coli/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Lipídeos de Membrana/metabolismo , Nanoestruturas/química , Tamanho da Partícula , Proteínas Citotóxicas Formadoras de Poros
16.
Int J Mol Sci ; 22(15)2021 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-34361084

RESUMO

Skin may be affected by many disorders that can be treated by topical applications of drugs on the action site. With the advent of nanotechnologies, new efficient delivery systems have been developed. Particularly, lipid-based nanosystems such as liposomes, ethosomes, transferosomes, solid lipid nanoparticles, nanostructured lipid carriers, cubosomes, and monoolein aqueous dispersions have been proposed for cutaneous application, reaching in some cases the market or clinical trials. This review aims to provide an overview of the different lipid-based nanosystems, focusing on their use for topical application. Particularly, biocompatible nanosystems able to dissolve lipophilic compounds and to control the release of carried drug, possibly reducing side effects, are described. Notably, the rationale to topically administer antioxidant molecules by lipid nanocarriers is described. Indeed, the structural similarity between the nanosystem lipid matrix and the skin lipids allows the achievement of a transdermal effect. Surely, more research is required to better understand the mechanism of interaction between lipid-based nanosystems and skin. However, this attempt to summarize and highlight the possibilities offered by lipid-based nanosystems could help the scientific community to take advantage of the benefits derived from this kind of nanosystem.


Assuntos
Permeabilidade da Membrana Celular , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Lipídeos/química , Nanopartículas/administração & dosagem , Pele/metabolismo , Animais , Humanos , Nanopartículas/química
17.
Science ; 373(6552)2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-34437126

RESUMO

Activation of cell-autonomous defense by the immune cytokine interferon-γ (IFN-γ) is critical to the control of life-threatening infections in humans. IFN-γ induces the expression of hundreds of host proteins in all nucleated cells and tissues, yet many of these proteins remain uncharacterized. We screened 19,050 human genes by CRISPR-Cas9 mutagenesis and identified IFN-γ-induced apolipoprotein L3 (APOL3) as a potent bactericidal agent protecting multiple non-immune barrier cell types against infection. Canonical apolipoproteins typically solubilize mammalian lipids for extracellular transport; APOL3 instead targeted cytosol-invasive bacteria to dissolve their anionic membranes into human-bacterial lipoprotein nanodiscs detected by native mass spectrometry and visualized by single-particle cryo-electron microscopy. Thus, humans have harnessed the detergent-like properties of extracellular apolipoproteins to fashion an intracellular lysin, thereby endowing resident nonimmune cells with a mechanism to achieve sterilizing immunity.


Assuntos
Apolipoproteínas L/metabolismo , Membrana Celular/metabolismo , Citosol/microbiologia , Bactérias Gram-Negativas/fisiologia , Interferon gama/imunologia , Apolipoproteínas L/química , Apolipoproteínas L/genética , Membrana Externa Bacteriana/metabolismo , Bacteriólise , Sistemas CRISPR-Cas , Membrana Celular/química , Membrana Celular/ultraestrutura , Permeabilidade da Membrana Celular , Células Cultivadas , Detergentes/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Edição de Genes , Bactérias Gram-Negativas/imunologia , Bactérias Gram-Negativas/patogenicidade , Bactérias Gram-Negativas/ultraestrutura , Humanos , Imunidade Inata , Lipoproteínas/química , Viabilidade Microbiana , Antígenos O/metabolismo , Domínios Proteicos , Salmonella typhimurium/imunologia , Salmonella typhimurium/patogenicidade , Salmonella typhimurium/fisiologia , Salmonella typhimurium/ultraestrutura , Solubilidade
18.
Nutrients ; 13(7)2021 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-34371979

RESUMO

Grape pomace (GP) is a winemaking by-product rich in polyphenols and fibre. Supplementation with GP extracts has shown potential benefits against oxidative stress- and inflammation-related pathologies. As a new nutritional target, this paper explores the impact of the ingestion of a grape pomace extract on intestinal barrier functionality. A GP extract was sequentially subjected to gastrointestinal and colonic digestion using the dynamic gastrointestinal simulator (simgi®). This generated two simulated fluids: intestinal-digested extract (IDE) and colonic-digested extract (CDE). The effects of these two fluids on paracellular permeability and the expression of tight junction (TJ) proteins (i.e., zonula occludens-1 (ZO-1) and occludin) were assessed in Caco-2-cell monolayers grown in Transwell® inserts. The IDE fluid significantly (p < 0.001) reduced the paracellular transport of FITC-dextran with respect to the control, whereas no significant differences (p > 0.05) were found for CDE, which could be due, at least partially, to the pro-leaky effect of the colonic digestion medium. Accordant slight increases in the mRNA levels of both ZO-1 and occludin were observed for IDE, but without statistical significance. Additionally, the colonic fermentation of the GP extract promoted the production of short-chain fatty acids (SCFA) and phenolic metabolites and led to changes in the relative abundance of some bacteria that might affect paracellular permeability. Overall, this paper reports first trends about the effects of grape pomace extracts on intestinal permeability that would require further confirmation in future experiments.


Assuntos
Digestão , Frutas/química , Microbioma Gastrointestinal/fisiologia , Intestinos/fisiologia , Extratos Vegetais/metabolismo , Vitis , Células CACO-2 , Permeabilidade da Membrana Celular/efeitos dos fármacos , Colo/química , Colo/metabolismo , Ácidos Graxos Voláteis/metabolismo , Fermentação , Microbioma Gastrointestinal/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Humanos , Ocludina/genética , Fenóis/metabolismo , Extratos Vegetais/administração & dosagem , Extratos Vegetais/farmacologia , RNA Mensageiro/análise , Proteínas de Junções Íntimas/genética , Vinho , Proteína da Zônula de Oclusão-1
19.
Cell Mol Life Sci ; 78(17-18): 6229-6249, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34387717

RESUMO

Pore-forming proteins (PFPs) are a heterogeneous group of proteins that are expressed and secreted by a wide range of organisms. PFPs are produced as soluble monomers that bind to a receptor molecule in the host cell membrane. They then assemble into oligomers that are incorporated into the lipid membrane to form transmembrane pores. Such pore formation alters the permeability of the plasma membrane and is one of the most common mechanisms used by PFPs to destroy target cells. Interestingly, PFPs can also indirectly manipulate diverse cellular functions. In recent years, increasing evidence indicates that the interaction of PFPs with lipid membranes is not only limited to pore-induced membrane permeabilization but is also strongly associated with extensive plasma membrane reorganization. This includes lateral rearrangement and deformation of the lipid membrane, which can lead to the disruption of target cell function and finally death. Conversely, these modifications also constitute an essential component of the membrane repair system that protects cells from the lethal consequences of pore formation. Here, we provide an overview of the current knowledge on the changes in lipid membrane organization caused by PFPs from different organisms.


Assuntos
Membrana Celular/metabolismo , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Membrana Celular/química , Permeabilidade da Membrana Celular , Complexo de Ataque à Membrana do Sistema Complemento/metabolismo , Endocitose , Humanos , Lipídeos de Membrana/metabolismo , Porinas/metabolismo
20.
ACS Appl Mater Interfaces ; 13(33): 39042-39054, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34375073

RESUMO

In developing a cluster-nanocarrier design, as a magnetic resonance imaging contrast agent, we have investigated the enhanced relaxivity of a manganese and iron-oxo cluster grafted within a porous polystyrene nanobead with increased relaxivity due to a higher surface area. The synthesis of the cluster-nanocarrier for the cluster Mn8Fe4O12(O2CC6H4CH═CH2)16(H2O)4, cross-linked with polystyrene (the nanocarrier), under miniemulsion conditions is described. By including a branched hydrophobe, iso-octane, the resulting nanobeads are porous and ∼70 nm in diameter. The increased surface area of the nanobeads compared to nonporous nanobeads leads to an enhancement in relaxivity; r1 increases from 3.8 to 5.2 ± 0.1 mM-1 s-1, and r2 increases from 11.9 to 50.1 ± 4.8 mM-1 s-1, at 9.4 teslas, strengthening the potential for T1 and T2 imaging. Several metrics were used to assess stability, and the porosity produced no reduction in metal stability. Synchrotron X-ray fluorescence microscopy was used to demonstrate that the nanobeads remain intact in vivo. In depth, physicochemical characteristics were determined, including extensive pharmacokinetics, in vivo imaging, and systemic biodistribution analysis.


Assuntos
Materiais Biocompatíveis/química , Meios de Contraste/química , Ferro/química , Manganês/química , Nanopartículas/química , Compostos Organometálicos/química , Poliestirenos/química , Animais , Materiais Biocompatíveis/farmacocinética , Linhagem Celular Tumoral , Permeabilidade da Membrana Celular , Sobrevivência Celular/efeitos dos fármacos , Meios de Contraste/farmacocinética , Reagentes para Ligações Cruzadas/química , Humanos , Imageamento por Ressonância Magnética , Camundongos Endogâmicos BALB C , Imagem Multimodal , Porosidade , Espectrometria por Raios X , Distribuição Tecidual
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...