RESUMO
222 nm far-ultraviolet (F-UV) light has a bactericidal effect similar to deep-ultraviolet (D-UV) light of about a 260 nm wavelength. The cytotoxic effect of 222 nm F-UV has not been fully investigated. DLD-1 cells were cultured in a monolayer and irradiated with 222 nm F-UV or 254 nm D-UV. The cytotoxicity of the two different wavelengths of UV light was compared. Changes in cell morphology after F-UV irradiation were observed by time-lapse imaging. Differences in the staining images of DNA-binding agents Syto9 and propidium iodide (PI) and the amount of cyclobutane pyrimidine dimer (CPD) were examined after UV irradiation. F-UV was cytotoxic to the monolayer culture of DLD-1 cells in a radiant energy-dependent manner. When radiant energy was set to 30 mJ/cm2, F-UV and D-UV showed comparable cytotoxicity. DLD-1 cells began to expand immediately after 222 nm F-UV light irradiation, and many cells incorporated PI; in contrast, PI uptake was at a low level after D-UV irradiation. The amount of CPD, an indicator of DNA damage, was higher in cells irradiated with D-UV than in cells irradiated with F-UV. This study proved that D-UV induced apoptosis from DNA damage, whereas F-UV affected membrane integrity in monolayer cells.
Assuntos
Apoptose , Membrana Celular , Neoplasias do Colo , Dano ao DNA , Raios Ultravioleta , Humanos , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Membrana Celular/efeitos da radiação , Neoplasias do Colo/patologia , Neoplasias do Colo/metabolismo , Apoptose/efeitos da radiação , Dímeros de Pirimidina/metabolismoRESUMO
This historical review of extracellular vesicles in the setting of exposure to ionizing radiation (IR) traces our understanding of how vesicles were initially examined and reported in the literature in the late 1970s (for secreted exosomes) and early 1980s (for plasma membrane-derived, exfoliated vesicles) to where we are now and where we may be headed in the next decade. An emphasis is placed on biophysical properties of extracellular vesicles, energy consumption and the role of vesiculation as an essential component of membrane turnover. The impact of intercellular signal trafficking by vesicle surface and intra-vesicular lipids, proteins, nucleic acids and metabolites is reviewed in the context of biomarkers for estimating individual radiation dose after exposure to radiation, pathogenesis of disease and development of cell-free therapeutics. Since vesicles express both growth stimulatory and inhibitory molecules, a hypothesis is proposed to consider superposition in a shared space and entanglement of molecules by energy sources that are external to human cells. Implications of this approach for travel in deep space are briefly discussed in the context of clinical disorders that have been observed after space travel.
Assuntos
Membrana Celular , Humanos , Membrana Celular/metabolismo , Membrana Celular/efeitos da radiação , Vesículas Extracelulares/efeitos da radiação , Vesículas Extracelulares/metabolismo , Radiometria , Voo Espacial , Animais , Sistema Livre de Células , História do Século XX , Radiação IonizanteRESUMO
Pulsed magnetic field treatment can enhance cell membrane permeability, allowing large molecular substances that normally cannot pass through the cell membrane to enter the cell. This research holds significant prospects for biomedical applications. However, the mechanism underlying pulsed magnetic field-induced cell permeabilization remains unclear, impeding further progress in research related to pulsed magnetic field. Currently, hypotheses about the mechanism are struggling to explain experimental results. Therefore, this study developed a parameter-adjustable pulsed magnetic field generator and designed experiments. Starting from the widely accepted hypothesis of "induced electric fields by pulsed magnetic field," we conducted a preliminary exploration of the biophysical mechanisms underlying pulsed magnetic field-induced cell permeabilization. Finally, we have arrived at an intriguing conclusion: under the current technical parameters, the impact of the pulsed magnetic field itself is the primary factor influencing changes in cell membrane permeability, rather than the induced electric field. This conclusion holds significant implications for understanding the biophysical mechanisms behind pulsed magnetic field therapy and its potential biomedical applications.
Assuntos
Permeabilidade da Membrana Celular , Campos Magnéticos , Permeabilidade da Membrana Celular/efeitos da radiação , Permeabilidade da Membrana Celular/fisiologia , Animais , Humanos , Membrana Celular/efeitos da radiação , Membrana Celular/fisiologiaRESUMO
Protein clustering is a powerful form of optogenetic control, yet remarkably few proteins are known to oligomerize with light. Recently, the photoreceptor BcLOV4 was found to form protein clusters in mammalian cells in response to blue light, although clustering coincided with its translocation to the plasma membrane, potentially constraining its application as an optogenetic clustering module. Herein we identify key amino acids that couple BcLOV4 clustering to membrane binding, allowing us to engineer a variant that clusters in the cytoplasm and does not associate with the membrane in response to blue light. This variant-called BcLOVclust-clustered over many cycles with substantially faster clustering and de-clustering kinetics compared to the widely used optogenetic clustering protein Cry2. The magnitude of clustering could be strengthened by appending an intrinsically disordered region from the fused in sarcoma (FUS) protein, or by selecting the appropriate fluorescent protein to which it was fused. Like wt BcLOV4, BcLOVclust activity was sensitive to temperature: light-induced clusters spontaneously dissolved at a rate that increased with temperature despite constant illumination. At low temperatures, BcLOVclust and Cry2 could be multiplexed in the same cells, allowing light control of independent protein condensates. BcLOVclust could also be applied to control signaling proteins and stress granules in mammalian cells. While its usage is currently best suited in cells and organisms that can be cultured below â¼30 °C, a deeper understanding of BcLOVclust thermal response will further enable its use at physiological mammalian temperatures.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Criptocromos , Proteínas da Matriz do Complexo de Golgi , Optogenética , Animais , Membrana Celular/química , Membrana Celular/efeitos da radiação , Análise por Conglomerados , Citoplasma/química , Citoplasma/efeitos da radiação , Luz , Criptocromos/química , Criptocromos/efeitos da radiação , Proteínas da Matriz do Complexo de Golgi/química , Proteínas da Matriz do Complexo de Golgi/efeitos da radiação , Proteínas Adaptadoras de Transdução de Sinal/química , Proteínas Adaptadoras de Transdução de Sinal/efeitos da radiação , Multimerização ProteicaRESUMO
The increasing and intensifying ultraviolet B (UVB) radiation in sunlight is an environmental threat to aquatic ecosystems, potentially affecting the entire life cycle of wild or aquacultural Pacific oyster Crassostrea gigas with photoreception. Due to its complex composition, plasma is an important biological specimen for investigating the degree of disturbance from its steady state caused by the external environment in the open-pipe-type hemolymph of mollusks. We performed a multi-omic analysis of C. gigas plasma exposed to daylight UVB radiation. Hub differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) were identified using the functional classification of Clusters of Orthologous Groups of proteins (COGs) through the protein-protein interaction (PPI)-based maximal clique centrality (MCC) algorithm. Our results summarize three types of UVB influences (disruption of the cell membrane, promotion of nucleotide metabolism, and inhibition of energy metabolism) on C. gigas based on transcriptomic, proteomic, and metabolomic analyses. The associated hub DEGs, DEPs (e.g., nucleoside diphosphate kinase, malate dehydrogenase, and hydroxyacyl-coenzyme A dehydrogenase), and metabolites (e.g., uridine, adenine, deoxyguanosine, guanosine, and xylitol) in the plasma were identified as biomarkers of mollusk response to UVB radiation, and could be used to evaluate the influence of environmental UVB on mollusks in future studies.
Assuntos
Membrana Celular , Crassostrea , Animais , Membrana Celular/metabolismo , Membrana Celular/efeitos da radiação , Crassostrea/fisiologia , Ecossistema , Metabolismo Energético , Nucleotídeos/metabolismo , Proteômica/métodosRESUMO
An eye lens is constantly exposed to the solar UV radiation, which is considered the most important external source of age-related changes to eye lens constituents. The accumulation of modifications of proteins and lipids with age can eventually lead to the development of progressive lens opacifications, such as cataracts. Though the impact of solar UV radiation on the structure and function of proteins is actively studied, little is known about the effect of photodamage on plasma membranes of lens cells. In this work we exploit Fluorescence Lifetime Imaging Microscopy (FLIM), together with viscosity-sensitive fluorophores termed molecular rotors, to study the changes in viscosity of plasma membranes of porcine eye lens resulting from two different types of photodamage: Type I (electron transfer) and Type II (singlet oxygen) reactions. We demonstrate that these two types of photodamage result in clearly distinct changes in viscosity - a decrease in the case of Type I damage and an increase in the case of Type II processes. Finally, to simulate age-related changes that occur in vivo, we expose an intact eye lens to UV-A light under anaerobic conditions. The observed decrease in viscosity within plasma membranes is consistent with the ability of eye lens constituents to sensitize Type I photodamage under natural irradiation conditions. These changes are likely to alter the transport of metabolites and predispose the whole tissue to the development of pathological processes such as cataracts.
Assuntos
Cristalino/efeitos da radiação , Raios Ultravioleta , Animais , Membrana Celular/efeitos da radiação , Técnicas In Vitro , Oxigênio Singlete/metabolismo , Suínos , ViscosidadeRESUMO
The purpose of this study was to verify whether the nanosecond pulsed electric field, not eliciting thermal effects, permanently changes the molecular processes and gene expression of Leydig TM3 cells. The cells were exposed to a moderate electric field (80 quasi-rectangular shape pulses, 60 ns pulse width, and an electric field of 14 kV/cm). The putative disturbances were recorded over 24 h. After exposure to the nanosecond pulsed electric field, a 19% increase in cell diameter, a loss of microvilli, and a 70% reduction in cell adhesion were observed. Some cells showed the nonapoptotic externalization of phosphatidylserine through the pores in the plasma membrane. The cell proportion in the subG1 phase increased by 8% at the expense of the S and G2/M phases, and the DNA was fragmented in a small proportion of the cells. The membrane mitochondrial potential and superoxide content decreased by 37% and 23%, respectively. Microarray's transcriptome analysis demonstrated a negative transient effect on the expression of genes involved in oxidative phosphorylation, DNA repair, cell proliferation, and the overexpression of plasma membrane proteins. We conclude that nanosecond pulsed electric field affected the physiology and gene expression of TM3 cells transiently, with a noticeable heterogeneity of cellular responses.
Assuntos
Biomarcadores/metabolismo , Eletricidade , Regulação da Expressão Gênica/efeitos da radiação , Células Intersticiais do Testículo/metabolismo , Nanotecnologia/métodos , Animais , Apoptose , Membrana Celular/metabolismo , Membrana Celular/efeitos da radiação , Movimento Celular , Proliferação de Células , Células Cultivadas , Eletroporação , Células Intersticiais do Testículo/efeitos da radiação , Masculino , Potencial da Membrana Mitocondrial , CamundongosRESUMO
A key aspect of living cells is their ability to harvest energy from the environment and use it to pump specific atomic and molecular species in and out of their system-typically against an unfavourable concentration gradient1. Active transport allows cells to store metabolic energy, extract waste and supply organelles with basic building blocks at the submicrometre scale. Unlike living cells, abiotic systems do not have the delicate biochemical machinery that can be specifically activated to precisely control biological matter2-5. Here we report the creation of microcapsules that can be brought out of equilibrium by simple global variables (illumination and pH), to capture, concentrate, store and deliver generic microscopic payloads. Borrowing no materials from biology, our design uses hollow colloids serving as spherical cell-membrane mimics, with a well-defined single micropore. Precisely tunable monodisperse capsules are the result of a synthetic self-inflation mechanism and can be produced in bulk quantities. Inside the hollow unit, a photoswitchable catalyst6 produces a chemical gradient that propagates to the exterior through the membrane's micropore and pumps target objects into the cell, acting as a phoretic tractor beam7. An entropic energy barrier8,9 brought about by the micropore's geometry retains the cargo even when the catalyst is switched off. Delivery is accomplished on demand by reversing the sign of the phoretic interaction. Our findings provide a blueprint for developing the next generation of smart materials, autonomous micromachinery and artificial cell-mimics.
Assuntos
Materiais Biomiméticos/metabolismo , Materiais Biomiméticos/efeitos da radiação , Biomimética , Membrana Celular/metabolismo , Coloides/metabolismo , Coloides/efeitos da radiação , Transporte Biológico Ativo/efeitos da radiação , Materiais Biomiméticos/química , Membrana Celular/efeitos da radiação , Coloides/química , Emulsões/química , Entropia , Concentração de Íons de Hidrogênio , LuzRESUMO
The effect of UV-light (240-390 nm) in doses of 151 and 755 J/m2 on the expression of membrane markers CD5, CD19, CD20 in human peripheral blood B cells was studied by flow cytometry. In 24 h after exposure to UV light, we observed activation of processes accompanied by structural rearrangements of B-cell membranes leading to changes in the expression of receptor molecules: the content of of CD19 and CD20 increased due to activation of the synthesis of these proteins, while the content of CD5 decreased. The percentage of CD5+ cells decreased over 24 h after UV-irradiation of lymphocytes, while addition of autologous plasma to the incubation medium produced a photoprotective effect on CD5+ cells.
Assuntos
Antígenos CD , Linfócitos B , Transfusão de Sangue Autóloga , Antígenos CD/metabolismo , Antígenos CD/efeitos da radiação , Antígenos CD19/metabolismo , Antígenos CD19/efeitos da radiação , Antígenos CD20/metabolismo , Antígenos CD20/efeitos da radiação , Linfócitos B/metabolismo , Linfócitos B/efeitos da radiação , Biomarcadores/metabolismo , Antígenos CD5/metabolismo , Antígenos CD5/efeitos da radiação , Membrana Celular/metabolismo , Membrana Celular/efeitos da radiação , Humanos , Imunidade Celular/efeitos da radiação , Imunoterapia/métodos , Raios Ultravioleta/efeitos adversosRESUMO
Iodine is an essential constituent of thyroid hormone. Active iodide accumulation in the thyroid is mediated by the sodium iodide symporter (NIS), comprising the first step in thyroid hormone biosynthesis, which relies on the functional expression of NIS on the cell membrane. The retention of NIS expressed in differentiated thyroid cancer (DTC) cells allows further treatment with post-operative radioactive iodine (RAI) therapy. However, compared with normal thyroid tissue, differentiated thyroid tumors usually show a decrease in the active iodide conveyance and NIS is generally retained within the cells, indicating that posttranslational protein transfer to the plasma membrane is abnormal. In recent years, through in vitro studies and studies of patients with DTC, various methods have been tested to increase the transport rate of NIS to the cell membrane and increase the absorption of iodine. An in-depth understanding of the mechanism of NIS transport to the plasma membrane could lead to improvements in RAI therapy. Therefore, in this review, we discuss the current knowledge concerning the post-translational mechanisms that regulate NIS transport to the cell membrane and the current status of redifferentiation therapy for patients with RAI-refractory (RAIR)-DTC.
Assuntos
Diferenciação Celular , Membrana Celular/efeitos da radiação , Radioisótopos do Iodo/uso terapêutico , Simportadores/metabolismo , Neoplasias da Glândula Tireoide/radioterapia , Animais , Membrana Celular/metabolismo , Humanos , Neoplasias da Glândula Tireoide/metabolismo , Neoplasias da Glândula Tireoide/patologiaRESUMO
The aim of this study was to evaluate the antibacterial activity of caffeic acid (CA), which is a natural polyphenol, combined with UV-A light against the representative foodborne bacteria Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes. Data regarding the inactivation of these bacteria and its dependence on CA concentration, light wavelength, and light dose were obtained. E. coli O157:H7 and Salmonella Typhimurium were reduced to the detection limit when treated with 3 mM CA and UV-A for 3 J/cm2 and 4 J/cm2, respectively, and 5 J/cm2 treatment induced 3.10 log reduction in L. monocytogenes. To investigate the mechanism for inactivation of Salmonella Typhimurium and L. monocytogenes, measurement of polyphenol uptake, membrane damage assessment, enzymatic activity assay, and transmission electron microscopy (TEM) were conducted. It was revealed that CA was significantly (P < 0.05) absorbed by bacterial cells, and UV-A light allowed a higher uptake of CA for both pathogens. Additionally, CA plus UV-A treatment induced significant (P < 0.05) cell membrane damage. In the enzymatic activity assay, the activities of both pathogens were reduced by CA, and a greater reduction occurred by use of CA plus UV-A. Moreover, transmission electron microscopy (TEM) images indicated that CA plus UV-A treatment notably destroyed the intercellular structure. In addition, antibacterial activity was also observed in commercial apple juice, which showed results similar to those obtained from phosphate-buffered saline (PBS), resulting in a significant (P < 0.05) reduction for all three pathogens without any changes in color parameters (L*, a*, and b*), total phenolic compounds, and DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity. IMPORTANCE Photodynamic inactivation (PDI), which involves photoactivation of a photosensitizer (PS), is an emerging field of study, as it effectively reduces various kinds of microorganisms. Although there are several PSs that have been used for PDI, there is a need to find naturally occurring PSs for safer application in the food industry. Caffeic acid, a natural polyphenol found in most fruits and vegetables, has recently been studied for its potential to act as a novel photosensitizer. However, no studies have been conducted regarding its antibacterial activity depending on treatment conditions and its antibacterial mechanism. In this study, we closely examined the effectiveness of caffeic acid in combination with UV-A light for inactivating representative foodborne bacteria in liquid medium. Therefore, the results of this research are expected to be utilized as basic data for future application of caffeic acid in PDI, especially when controlling pathogens in liquid food processing.
Assuntos
Antibacterianos/farmacologia , Ácidos Cafeicos/farmacologia , Escherichia coli O157 , Conservação de Alimentos/métodos , Sucos de Frutas e Vegetais/microbiologia , Listeria monocytogenes , Salmonella typhimurium , Raios Ultravioleta , Membrana Celular/efeitos dos fármacos , Membrana Celular/efeitos da radiação , Escherichia coli O157/efeitos dos fármacos , Escherichia coli O157/crescimento & desenvolvimento , Escherichia coli O157/metabolismo , Escherichia coli O157/efeitos da radiação , Microbiologia de Alimentos , Frutas , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Listeria monocytogenes/metabolismo , Listeria monocytogenes/efeitos da radiação , Malus , Polifenóis/metabolismo , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/crescimento & desenvolvimento , Salmonella typhimurium/metabolismo , Salmonella typhimurium/efeitos da radiaçãoRESUMO
Plasma membrane repair is essential for eukaryotic cell life and is triggered by the influx of calcium through membrane wounds. Repair consists of sequential steps, with closure of the membrane hole being the key event that allows the cell to recover, thus identifying the kinetics of hole closure as important for clarifying repair mechanisms and as a quantitative handle on repair efficiency. We implement calcium imaging in MCF7 breast carcinoma cells subject to laser damage, coupled with a model describing the spatio-temporal calcium distribution. The model identifies the time point of hole closure as the time of maximum calcium signal. Analysis of cell data estimates the closure time as: [Formula: see text] s and [Formula: see text] s using GCaMP6s-CAAX and GCaMP6s probes respectively. The timescale was confirmed by independent time-lapse imaging of a hole during sealing. Moreover, the analysis estimates the characteristic time scale of calcium removal, the penetration depth of the calcium wave and the diffusion coefficient. Probing of hole closure times emerges as a strong universal tool for quantification of plasma membrane repair.
Assuntos
Sinalização do Cálcio , Cálcio/metabolismo , Membrana Celular/metabolismo , Modelos Biológicos , Imagem Molecular , Linhagem Celular Tumoral , Membrana Celular/efeitos da radiação , Permeabilidade da Membrana Celular , Análise de Dados , Humanos , Microscopia de Fluorescência , Imagem Molecular/métodos , Fatores de Tempo , Raios UltravioletaRESUMO
Tethered photoswitches are molecules with two photo-dependent isomeric forms, each with different actions on their biological targets. They include reactive chemical groups capable of covalently binding to their target. Our aim was to develop a ß-subunit-tethered propofol photoswitch (MAP20), as a tool to better study the mechanism of anesthesia through the GABAA α1ß3γ2 receptor. We used short spacers between the tether (methanethiosulfonate), the photosensitive moiety (azobenzene), and the ligand (propofol), to allow a precise tethering adjacent to the putative propofol binding site at the ß+α- interface of the receptor transmembrane helices (TMs). First, we used molecular modeling to identify possible tethering sites in ß3TM3 and α1TM1, and then introduced cysteines in the candidate positions. Two mutant subunits [ß3(M283C) and α1(V227C)] showed photomodulation of GABA responses after incubation with MAP20 and illumination with lights at specific wavelengths. The α1ß3(M283C)γ2 receptor showed the greatest photomodulation, which decreased as GABA concentration increased. The location of the mutations that produced photomodulation confirmed that the propofol binding site is located in the ß+α- interface close to the extracellular side of the transmembrane helices. Tethering the photoswitch to cysteines introduced in the positions homologous to ß3M283 in two other subunits (α1W288 and γ2L298) also produced photomodulation, which was not entirely reversible, probably reflecting the different nature of each interface. The results are in agreement with a binding site in the ß+α- interface for the anesthetic propofol.
Assuntos
Anestésicos Intravenosos/farmacologia , Membrana Celular/metabolismo , Luz , Oócitos/metabolismo , Propofol/farmacologia , Receptores de GABA-A/metabolismo , Animais , Membrana Celular/efeitos dos fármacos , Membrana Celular/efeitos da radiação , Humanos , Oócitos/efeitos dos fármacos , Oócitos/efeitos da radiação , Conformação Proteica , Domínios Proteicos , Receptores de GABA-A/química , Receptores de GABA-A/efeitos dos fármacos , Receptores de GABA-A/efeitos da radiação , Xenopus laevis , Ácido gama-AminobutíricoRESUMO
BACKGROUND: In a recent study we showed that blue light inactivates methicillin-resistant Staphylococcus aureus (MRSA) by perturbing, depolarizing, and disrupting its cell membrane. PURPOSE: The current study presents visual evidence that the observed biochemical changes also result in cell metabolic changes and structural alteration of the cell membrane. METHODS: Cultures of MRSA were treated with 450 nm pulsed blue light (PBL) at 3 mW/cm2 irradiance, using a sub lethal dose of 2.7 J/cm2 radiant exposure three times at 30-min intervals. Following 24 h incubation at 37 °C, irradiated colonies and control non-irradiated colonies were processed for light and transmission electron microscopy. RESULTS: The images obtained revealed three major effects of PBL; (1) disruption of MRSA cell membrane, (2) alteration of membrane structure, and (3) disruption of cell replication. CONCLUSION: These signs of bacterial inactivation at a dose deliberately selected to be sub-lethal supports our previous finding that rapid depolarization of bacterial cell membrane and disruption of cellular function comprise another mechanism underlying photo-inactivation of bacteria. Further, it affirms the potency of PBL.
Assuntos
Membrana Celular/efeitos da radiação , Staphylococcus aureus Resistente à Meticilina/efeitos da radiação , Técnicas de Cultura de Células , Contagem de Colônia Microbiana , Relação Dose-Resposta à Radiação , Luz , Staphylococcus aureus Resistente à Meticilina/metabolismo , Viabilidade Microbiana/efeitos da radiaçãoRESUMO
Photodynamic therapy (PDT) has emerged as one of the most up-and-coming non-invasive therapeutic modalities for cancer therapy in rencent years. However, its therapeutic effect was still hampered by the short life span, limited diffusion distance and ineluctable depletion of singlet oxygen (1O2), as well as the hypoxic microenvironment in the tumor tissue. Such problems have limited the application of PDT and appropriate solutions are highly demand. Methods: Herein, a programmatic treatment strategy is proposed for the development of a smart molecular prodrug (D-bpy), which comprise a two-photon photosensitizer and a hypoxia-activated chemotherapeutic prodrug. A rhodamine dye was designed to connect them and track the drug release by the fluorescent signal generated through azo bond cleavage. Results: The prodrug (D-bpy) can stay on the cell membrane and enrich at the tumor site. Upon light irradiation, the therapeutic effect was enhanced by a stepwise treatment: (i) direct generation of 1O2 on the cell membrane induced membrane destruction and promoted the D-bpy uptake; (ii) deep tumor hypoxia caused by two-photon PDT process further triggered the activation of the chemotherapy prodrug. Both in vitro and in vivo experiments, D-bpy have exhabited excellent tumor treatment effect. Conclusion: The innovative programmatic treatment strategy provides new strategy for the design of follow-up anticancer drugs.
Assuntos
Hipóxia/tratamento farmacológico , Neoplasias Mamárias Experimentais/tratamento farmacológico , Fotoquimioterapia/métodos , Fótons , Fármacos Fotossensibilizantes/farmacologia , Pró-Fármacos/farmacologia , Animais , Compostos Azo/química , Membrana Celular/patologia , Membrana Celular/efeitos da radiação , Feminino , Corantes Fluorescentes/química , Células HeLa , Humanos , Hipóxia/metabolismo , Hipóxia/patologia , Neoplasias Mamárias Experimentais/química , Neoplasias Mamárias Experimentais/patologia , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/efeitos da radiação , Pró-Fármacos/síntese química , Pró-Fármacos/efeitos da radiação , Rodaminas/química , Oxigênio Singlete/química , Coloração e Rotulagem/métodosRESUMO
The lipid composition impacts directly on the structure and function of the cytoplasmic as well as organelle membranes. Depending on the type of membrane, specific lipids are required to accommodate, intercalate, or pack membrane proteins to the proper functioning of the cells/organelles. Rather than being only a physical barrier that separates the inner from the outer spaces, membranes are responsible for many biochemical events such as cell-to-cell communication, protein-lipid interaction, intracellular signaling, and energy storage. Photochemical reactions occur naturally in many biological membranes and are responsible for diverse processes such as photosynthesis and vision/phototaxis. However, excessive exposure to light in the presence of absorbing molecules produces excited states and other oxidant species that may cause cell aging/death, mutations and innumerable diseases including cancer. At the same time, targeting key compartments of diseased cells with light can be a promising strategy to treat many diseases in a clinical procedure called Photodynamic Therapy. Here we analyze the relationships between membrane alterations induced by photo-oxidation and the biochemical responses in mammalian cells. We specifically address the impact of photosensitization reactions in membranes of different organelles such as mitochondria, lysosome, endoplasmic reticulum, and plasma membrane, and the subsequent responses of eukaryotic cells.
Assuntos
Membrana Celular/metabolismo , Membrana Celular/efeitos da radiação , Luz , Animais , Humanos , Oxirredução/efeitos da radiaçãoRESUMO
The perforation of plasma membrane by ultrasound-driven microbubbles (i.e., sonoporation) provides a temporary window for transporting macromolecules into the cytoplasm that is promising with respect to drug delivery and gene therapy. To improve the efficacy of delivery while ensuring biosafety, membrane resealing and cell recovery are required to help sonoporated cells defy membrane injury and regain their normal function. Blebs are found to accompany the recovery of sonoporated cells. However, the spatiotemporal characteristics of blebs and the underlying mechanisms remain unclear. With a customized platform for ultrasound exposure and 2-D/3-D live single-cell imaging, localized membrane perforation was induced with ultrasound-driven microbubbles, and the cellular responses were monitored using multiple fluorescent probes. The results indicated that localized blebs undergoing four phases (nucleation, expansion, pausing and retraction) on a time scale of tens of seconds to minutes were specifically involved in the reversibly sonoporated cells. The blebs spatially correlated with the membrane perforation site and temporally lagged (about tens of seconds to minutes) the resealing of perforated membrane. Their diameter (about several microns) and lifetime (about tens of seconds to minutes) positively correlated with the degree of sonoporation. Further studies revealed that intracellular calcium transients might be an upstream signal for triggering blebbing nucleation; exocytotic lysosomes not only contributed to resealing of the perforated membrane, but also to the increasing bleb volume during expansion; and actin components accumulation facilitated bleb retraction. These results provide new insight into the short-term strategies that the sonoporated cell employs to recover on membrane perforation and to remodel membrane structure and a biophysical foundation for sonoporation-based therapy.
Assuntos
Membrana Celular/efeitos da radiação , Microbolhas , Ondas Ultrassônicas , Membrana Celular/fisiologia , Células HeLa , Humanos , Células Tumorais CultivadasRESUMO
In our previous study, we have demonstrated that curcumin can efficiently kill the anaerobic bacterium Propionibacterium acnes by irradiation with low-dose blue light. The curcuminoids present in natural plant turmeric mainly include curcumin, demethoxycurcumin, and bisdemethoxycurcumin. However, only curcumin is commercially available. Eighteen different curcumin analogs, including demethoxycurcumin and bisdemethoxycurcumin, were synthesized in this study. Their antibacterial activity against Gram-positive aerobic bacteria Staphylococcus aureus and Staphylococcus epidermidis was investigated using the photodynamic inactivation method. Among the three compounds in turmeric, curcumin activity is the weakest, and bisdemethoxycurcumin possesses the strongest activity. However, two synthetic compounds, (1E,6E)-1,7-bis(5-methylthiophen-2-yl)hepta-1,6-diene-3,5-dione and (1E,6E)-1,7-di(thiophen-2-yl)hepta-1,6-diene-3,5-dione, possess the best antibacterial activity among all compounds examined in this study. Their chemical stability is also better than that of bisdemethoxycurcumin, and thus has potential for future clinical applications.
Assuntos
Diarileptanoides/farmacologia , Bactérias Gram-Positivas/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacos , Fotoquimioterapia , Membrana Celular/efeitos dos fármacos , Membrana Celular/efeitos da radiação , Membrana Celular/ultraestrutura , Diarileptanoides/síntese química , Diarileptanoides/química , Bactérias Gram-Positivas/efeitos da radiação , Bactérias Gram-Positivas/ultraestrutura , Luz , Testes de Sensibilidade MicrobianaRESUMO
This study investigated physiological alterations involved in the inactivation of Levilactobacillus (L.) brevis and Leuconostoc (Lc.) mesenteroides in orange juice caused by Citrus lemon essential oil (CLEO) and C. reticulata essential oil (CREO) alone and combined with mild heat treatment (MHT). Damage in DNA, membrane integrity, membrane potential, metabolic and efflux activity of bacterial cells were measured after exposure (6 and 12 min) to CLEO or CREO (0.5 µL/mL) and/or MHT (54 °C) using flow cytometry. Limonene was the major constituent in CLEO (66.4%) and CREO (89.4%). The size of the damaged cell subpopulations increased (p < 0.05) after longer exposure time and varied with the tested essential oil and/or bacterial isolate. After exposure to CLEO and CREO alone, the cell subpopulations with damage in measured physiological functions were in a range of 19.6-66.8% and 23.8-75.9%, respectively. Exposure to CREO resulted in larger Lc. mesenteroides cell subpopulations (35.4-68.7%) with damaged DNA, permeabilized and depolarized membrane and compromised metabolic or efflux activity compared to L. brevis (23.8-58.0%). In contrast, exposure to CLEO led to higher damaged L. brevis cell subpopulations (35.1-77%) compared to Lc. mesenteroides (25.3-36.6%). Exposure to combined treatments (CLEO or CREO and MHT) affected the measured physiological functions in almost the entire L. brevis and Lc. mesenteroides cell population (up to 99%), although the damage extension on each isolate varied with tested essential oil. Results show that inactivation of L. brevis and Lc. mesenteroides cells caused by CLEO and CREO alone and combined with MHT in orange juice involves a multi-target action, which causes DNA damage, altered permeability and depolarization of membrane and compromised metabolic and efflux activities.
Assuntos
Citrus/química , Sucos de Frutas e Vegetais/microbiologia , Temperatura Alta , Lactobacillales/fisiologia , Óleos Voláteis/farmacologia , Pasteurização/métodos , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Membrana Celular/efeitos da radiação , Dano ao DNA , Microbiologia de Alimentos , Lactobacillales/classificação , Lactobacillales/efeitos dos fármacos , Lactobacillales/efeitos da radiação , Óleos Voláteis/química , Fatores de TempoRESUMO
This study examined the antibacterial effect of protoporphyrin IX-ethylenediamine derivative (PPIX-ED)-mediated photodynamic antimicrobial chemotherapy (PPIX-ED-PACT) against Pseudomonas aeruginosa in vitro and in vivo. PPIX-ED potently inhibited the growth of Pseudomonas aeruginosa by inducing reactive oxygen species production via photoactivation. Atomic force microscopy revealed that PPIX-ED-PACT induced the leakage of bacterial content by degrading the bacterial membrane and wall. As revealed using acridine orange/ethidium bromide staining, PPIX-ED-PACT altered the permeability of the bacterial membrane. In addition, the antibacterial effect of PPIX-ED-PACT was demonstrated in an in vivo model of P. aeruginosa-infected wounds. PPIX-ED (100 µM) decreased the number of P. aeruginosa colony-forming units by 4.2 log10. Moreover, histological analysis illustrated that the wound healing rate was 98% on day 14 after treatment, which was 10% higher than that in the control group. According to the present findings, PPIX-ED-PACT can effectively inhibit the growth of P. aeruginosa in vitro and in vivo.