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63 result(s) for "Pállinger, Éva"
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Low-density lipoprotein mimics blood plasma-derived exosomes and microvesicles during isolation and detection
Circulating extracellular vesicles have emerged as potential new biomarkers in a wide variety of diseases. Despite the increasing interest, their isolation and purification from body fluids remains challenging. Here we studied human pre-prandial and 4 hours postprandial platelet-free blood plasma samples as well as human platelet concentrates. Using flow cytometry, we found that the majority of circulating particles within the size range of extracellular vesicles lacked common vesicular markers. We identified most of these particles as lipoproteins (predominantly low-density lipoprotein, LDL) which mimicked the characteristics of extracellular vesicles and also co-purified with them. Based on biophysical properties of LDL this finding was highly unexpected. Current state-of-the-art extracellular vesicle isolation and purification methods did not result in lipoprotein-free vesicle preparations from blood plasma or from platelet concentrates. Furthermore, transmission electron microscopy showed an association of LDL with isolated vesicles upon in vitro mixing. This is the first study to show co-purification and in vitro association of LDL with extracellular vesicles and its interference with vesicle analysis. Our data point to the importance of careful study design and data interpretation in studies using blood-derived extracellular vesicles with special focus on potentially co-purified LDL.
Improved Characterization of EV Preparations Based on Protein to Lipid Ratio and Lipid Properties
In recent years the study of extracellular vesicles has gathered much scientific and clinical interest. As the field is expanding, it is becoming clear that better methods for characterization and quantification of extracellular vesicles as well as better standards to compare studies are warranted. The goal of the present work was to find improved parameters to characterize extracellular vesicle preparations. Here we introduce a simple 96 well plate-based total lipid assay for determination of lipid content and protein to lipid ratios of extracellular vesicle preparations from various myeloid and lymphoid cell lines as well as blood plasma. These preparations included apoptotic bodies, microvesicles/microparticles, and exosomes isolated by size-based fractionation. We also investigated lipid bilayer order of extracellular vesicle subpopulations using Di-4-ANEPPDHQ lipid probe, and lipid composition using affinity reagents to clustered cholesterol (monoclonal anti-cholesterol antibody) and ganglioside GM1 (cholera toxin subunit B). We have consistently found different protein to lipid ratios characteristic for the investigated extracellular vesicle subpopulations which were substantially altered in the case of vesicular damage or protein contamination. Spectral ratiometric imaging and flow cytometric analysis also revealed marked differences between the various vesicle populations in their lipid order and their clustered membrane cholesterol and GM1 content. Our study introduces for the first time a simple and readily available lipid assay to complement the widely used protein assays in order to better characterize extracellular vesicle preparations. Besides differentiating extracellular vesicle subpopulations, the novel parameters introduced in this work (protein to lipid ratio, lipid bilayer order, and lipid composition), may prove useful for quality control of extracellular vesicle related basic and clinical studies.
Proteomic analysis of plasma-derived extracellular vesicles: pre- and postprandial comparisons
Extracellular vesicles (EVs) are key in intercellular communication, carrying biomolecules like nucleic acids, lipids, and proteins. This study investigated postprandial characteristics and proteomic profiles of blood-derived EVs in healthy individuals. Twelve participants fasted overnight before baseline assessments. After consuming a controlled isocaloric meal, EVs were isolated for proteomic and flow cytometric analysis. Plasma triacylglyceride levels confirmed fasting completion, while protein concentrations in plasma and EVs were monitored for postprandial stability. Proteomic analysis identified upregulated proteins related to transport mechanisms and epithelial/endothelial functions postprandially, indicating potential roles in physiological responses to nutritional intake. Enrichment analyses revealed vesicle-related pathways and immune system processes. Flow cytometry showed increased expression of CD324 on CD9 + CD63 + CD81 + large extracellular vesicles postprandially, suggesting an epithelial origin. These findings offer valuable insights into postprandial EV dynamics and their potential physiological significance, highlighting the need for stringent fasting guidelines in EV studies to account for postprandial effects on EV composition and function.
Comparative Study of Ferrocene- and Indene-Based Tamoxifen Derivatives of Different Molecular Flexibility on High-Mortality Cancer Cell Lines
Tamoxifen is a well-established selective estrogen receptor modulator (SERM) widely used in breast cancer treatment, yet its efficacy varies across tumor types. To enhance its antitumor potential, we previously synthesized and investigated novel ferrocene-linked (T5, T15) derivatives. This publication is a close continuation of this work, introducing a new indene-based (T6) derivative. Objectives: The main aim of this study was to further broaden our knowledge of the mechanism behind the increased antitumor effect of the ferrocene-linked drugs (T5 and T15) and compare it with a new, indene-based tamoxifen derivative, T6. The indene moiety was selected as a rigid, hydrophobic aromatic unit to probe pharmacological effects independent of ferrocene’s redox activity. Methods: The compounds were tested on MCF7, MDA-MB231 and PANC1 cells. Cell viability was assessed with the AlamarBlue assay and the xCELLigence SP system. Reactive oxygen species (ROS) production was measured with the ROS Glo assay. Flow cytometry and RT-qPCR experiments were conducted to assess apoptosis and ROS regulation as well. Results: The modified compounds demonstrated an increased cell-viability-decreasing effect in breast (MCF7, MDA-MB-231) and pancreatic (PANC1) cancer cell lines, influencing both estrogen-receptor-dependent and -independent pathways. T6 led to G2/M phase arrest in PANC1 cells. Beyond cell cycle disruption, these derivatives significantly elevated ROS levels, contributing to apoptosis. Conclusions: Our findings suggest that these structural modifications retain tamoxifen’s pharmacophore properties while expanding its mechanism of action, particularly through universal interactions independent of the ER status of tumor cells. The enhanced antitumor effects highlight the potential of these derivatives as promising candidates for improved cancer therapies.
Associations between Various Inflammatory Markers and Carotid Findings in a Voluntary Asymptomatic Population Sample
Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide, and atherosclerosis is the key factor promoting its development. Carotid intima-media thickening and the presence of carotid plaques are important indices of cardiovascular risk. In addition, inflammation is a major and complex factor in the development of atherosclerosis. The relationships between carotid atherosclerosis and certain inflammatory markers have rarely been studied in healthy individuals. Therefore, we aimed to investigate the associations between subclinical carotid atherosclerosis and various inflammatory biomarkers in a large Caucasian population free of evident CVD. In addition to recording study participants’ demographic characteristics, anthropometric characteristics, and atherosclerotic risk factors, laboratory tests were performed to measure levels of hemoglobin A1c (HbA1c), high-sensitivity C-reactive protein, and inflammatory cytokines/chemokines, including interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-12p70, IL-17A, IL-18, IL-23, IL-33, interferon (IFN)-α2, IFN-γ, tumor necrosis factor-α, and monocyte chemoattractant protein (MCP)-1. This study included 264 asymptomatic individuals with a median age of 61.7 years (interquartile range, 54.5–67.5 years); 45.7% of participants were male. Participants were divided into two groups according to their carotid status: the normal carotid group, comprising 120 participants; and the pathological carotid group, comprising 144 participants. Compared with the normal carotid group, hypertension and diabetes mellitus were significantly more common and serum levels of HbA1c, IL-8, and MCP-1 were significantly higher in the pathological carotid group. Multivariate regression analysis revealed significant positive associations between pathological carotid findings and serum levels of IL-8 (highest tertile, OR: 2.4, p = 0.030) and MCP-1 (highest tertile, OR: 2.4, p = 0.040). Our results suggest that IL-8 and MCP-1 may serve as early indicators of subclinical atherosclerosis, thereby helping to identify individuals at increased risk of CVD before the onset of clinical symptoms.
Pattern of Regulatory T Cells, Resident Memory T Cells, and Exhausted T Cells in Human Pericardial Fluid Samples of Cardiovascular Patients
This study investigates T cell subsets in pericardial fluid samples obtained from heart transplantation donors, heart transplantation recipients, and coronary artery bypass graft patients. Using flow cytometry, we characterized regulatory T cells (Tregs), tissue-resident memory T cells (Trm), and exhausted T cells based on specific markers. Our results showed significant alterations in the CD4+ and CD8+ T cell subsets, migration (CXCR3, CCR5), and exhaustion markers (PD-1, TIM3) across the groups. Notably, Tregs and Trm cells were enriched in recipients, while markers of T cell exhaustion showed a complex regulation. These findings provide novel insights into the local immune regulation in cardiac disease and transplantation.
Isolation and Characterization of Tissue-Derived Extracellular Vesicles from Mouse Lymph Nodes
Extracellular vesicles (EVs) are lipid membrane-enclosed particles released by all cells and can be isolated from various sources, even from solid tissues. This study focuses on isolating and characterizing EVs from mouse lymph nodes (LNs). Male C57BL/6 mice were injected with complete Freund’s adjuvant, with or without ovalbumin. Inguinal and popliteal LNs were incised 9 days after immunization, and EV isolation was carried out using a combination of differential centrifugation and size-exclusion chromatography. The characteristic morphology of small and large EVs was confirmed by transmission electron microscopy. Particle size distribution and concentration were determined by nanoparticle tracking analysis, while protein and lipid contents were measured by bicinchoninic acid assay, and sulfo-phospho-vanillin assays, respectively, to calculate the protein-to-lipid ratio. Immune and EV markers were analyzed by using flow cytometry and Western blot assay, revealing significant changes between immunized mice compared to controls. This study establishes a novel protocol for isolating and characterizing EVs from LNs and highlights the impact of immunization on EV properties, offering insights into their roles in immune processes.
Plasma neutrophil extracellular trap level is modified by disease severity and inhaled corticosteroids in chronic inflammatory lung diseases
A flow cytometry-based method was developed to quantify in vivo circulating neutrophil extracellular trap (NET) levels in plasma and compare them in patients with different chronic inflammatory lung diseases. Seventeen asthmatic and 11 control children, 12 adult controls, 46 asthmatic, 6 COPD and 6 adult patients with asthma-COPD overlap syndrome (ACOS) were recruited in the study. The presence of NETs in unstimulated cell-free plasma was confirmed and visualized by confocal laser-scanning microscopy. No significant differences were found in plasma NET levels between children and adults, children with or without asthma and adults with or without asthma, COPD or ACOS. When asthmatic patients were stratified according to their disease severity the average plasma NET level was significantly higher in asthmatic patients with more serious symptoms (adjusted p = 0.027). Patients with poorer pulmonary functions had higher plasma NET levels which negatively correlated with the FEV1 values (r = −0.39, p = 0.002). Patients who were medicated daily with inhaled corticosteroids (ICS) had significantly lower average plasma NET level than patients who did not or just occasionally used ICS (p = 0.027). If further studies confirm the NET-lowering effect of ICS in the circulation, it can be utilized in diseases where NETosis contributes to the pathogenesis.
Effects of light exposure during IVF: transcriptomic analysis of murine embryos and embryo-derived EVs
Light exposure of embryos during assisted reproduction affects embryo quality and implantation capacity in a wavelength dependent manner. We investigated the molecular mechanism of these light-induced changes through the comparative analysis of gene expression and regulatory miRNA profile of murine embryos cultured in dark environment and those exposed to white- or red filtered light. miRNA sequencing was used to assess the role of embryo-derived extracellular vesicles in the endometrium-embryo dialogue. cultured mouse embryos at 3.5 days post coitum (dpc) were exposed to white or red filtered light. After 24 hours mRNA and miRNA content of the embryos as well as the miRNA content of embryo-derived extracellular vesicles were isolated and RNA-sequencing was performed. Differential expression analysis and functional enrichment analysis were used for evaluating the transcriptome results. Light exposure caused transcriptomic changes in the embryos. White light upregulated apoptotic pathways, while red filtered light gave rise to the activation of regeneration pathways, including DNA repair mechanisms. Embryo-derived extracellular vesicles enclosed wavelength dependently unique miRNA cargos the target genes of which play a role in embryo implantation. White light upregulates apoptotic pathways, at both the transcriptome and regulatory miRNAs levels. Red filtration partially counterbalances these negative effects by shifting the cellular processes towards regeneration, including DNA repair mechanisms. Extracellular vesicles of light exposed embryos play a role in blastocyst-decidua communication through the horizontal transfer of regulatory miRNAs. Our data prove that light exposure during fertilization modifies cell function that might affect the outcome of implantation.
Antibacterial Effects of Bicarbonate in Media Modified to Mimic Cystic Fibrosis Sputum
Cystic fibrosis (CF) is a hereditary disease caused by mutations in the gene encoding an epithelial anion channel. In CF, Cl− and HCO3− hyposecretion, together with mucin hypersecretion, leads to airway dehydration and production of viscous mucus. This habitat is ideal for colonization by pathogenic bacteria. We have recently demonstrated that HCO3− inhibits the growth and biofilm formation of Pseudomonas aeruginosa and Staphylococcus aureus when tested in laboratory culture media. Using the same bacteria our aim was to investigate the effects of HCO3− in artificial sputum medium (ASM), whose composition resembles CF mucus. Control ASM containing no NaHCO3 was incubated in ambient air (pH 7.4 or 8.0). ASM containing NaHCO3 (25 and 100 mM) was incubated in 5% CO2 (pH 7.4 and 8.0, respectively). Viable P. aeruginosa and S. aureus cells were counted by colony-forming unit assay and flow cytometry after 6 h and 17 h of incubation. Biofilm formation was assessed after 48 h. The data show that HCO3− significantly decreased viable cell counts and biofilm formation in a concentration-dependent manner. These effects were due neither to extracellular alkalinization nor to altered osmolarity. These results show that HCO3− exerts direct antibacterial and antibiofilm effects on prevalent CF bacteria.