TY - JOUR AU - Pethő, Zoltán Dénes AU - Pajtás, Dávid AU - Piga, Martina AU - Magyar, Zsuzsanna Édua AU - Zákány, Florina AU - Kovács, Tamás AU - Zidar, Nace AU - Panyi, György AU - Varga, Zoltán AU - Papp, Ferenc TI - A synthetic flavonoid derivate in the plasma membrane transforms the voltage‐clamp fluorometry signal of CiHv1 JF - FEBS JOURNAL J2 - FEBS J PY - 2024 PG - 18 SN - 1742-464X DO - 10.1111/febs.17105 UR - https://m2.mtmt.hu/api/publication/34722791 ID - 34722791 N1 - Early View AB - Voltage‐clamp fluorometry (VCF) enables the study of voltage‐sensitive proteins through fluorescent labeling accompanied by ionic current measurements for voltage‐gated ion channels. The heterogeneity of the fluorescent signal represents a significant challenge in VCF. The VCF signal depends on where the cysteine mutation is incorporated, making it difficult to compare data among different mutations and different studies and standardize their interpretation. We have recently shown that the VCF signal originates from quenching amino acids in the vicinity of the attached fluorophores, together with the effect of the lipid microenvironment. Based on these, we performed experiments to test the hypothesis that the VCF signal could be altered by amphiphilic quenching molecules in the cell membrane. Here we show that a phenylalanine‐conjugated flavonoid (4‐oxo‐2‐phenyl‐4H‐chromene‐7‐yl)‐phenylalanine, (later Oxophench) has potent effects on the VCF signals of the Ciona intestinalis H V 1 (CiHv1) proton channel. Using spectrofluorimetry, we showed that Oxophench quenches TAMRA (5(6)‐carboxytetramethylrhodamine‐(methane thiosulfonate)) fluorescence. Moreover, Oxophench reduces the baseline fluorescence in oocytes and incorporates into the cell membrane while reducing the membrane fluidity of HEK293 cells. Our model calculations confirmed that Oxophench, a potent membrane‐bound quencher, modifies the VCF signal during conformational changes. These results support our previously published model of VCF signal generation and point out that a change in the VCF signal may not necessarily indicate an altered conformational transition of the investigated protein. LA - English DB - MTMT ER - TY - CONF AU - Ilagan, Roger AU - Gentzsch, Martina AU - Maléth, József AU - L., Quinney Nancy AU - Szabó, Viktória AU - Zákány, Florina AU - Basa-Dénes, Orsolya AU - Molnár, László AU - Mándity, István TI - TAVT-135, a novel chloride ion transporter for the pan-genotypic treatment of cystic fibrosis: electrophysiological and mucus-hydration properties T2 - 18th ECFS Basic Science Conference PY - 2023 SP - 69 UR - https://m2.mtmt.hu/api/publication/34657516 ID - 34657516 LA - English DB - MTMT ER - TY - JOUR AU - Zákány, Florina AU - Mándity, István AU - Varga, Zoltán AU - Panyi, György AU - Nagy, Péter AU - Kovács, Tamás TI - Effect of the Lipid Landscape on the Efficacy of Cell-Penetrating Peptides JF - CELLS J2 - CELLS-BASEL VL - 12 PY - 2023 IS - 13 PG - 29 SN - 2073-4409 DO - 10.3390/cells12131700 UR - https://m2.mtmt.hu/api/publication/34037015 ID - 34037015 N1 - Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, 4032, Hungary Department of Organic Chemistry, Faculty of Pharmacy, Semmelweis University, Budapest, 1085, Hungary TTK Lendület Artificial Transporter Research Group, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Budapest, 1117, Hungary Export Date: 16 October 2023 Correspondence Address: Nagy, P.; Department of Biophysics and Cell Biology, Hungary; email: nagyp@med.unideb.hu Correspondence Address: Kovacs, T.; Department of Biophysics and Cell Biology, Hungary; email: kovacs.tamas@med.unideb.hu AB - Every cell biological textbook teaches us that the main role of the plasma membrane is to separate cells from their neighborhood to allow for a controlled composition of the intracellular space. The mostly hydrophobic nature of the cell membrane presents an impenetrable barrier for most hydrophilic molecules larger than 1 kDa. On the other hand, cell-penetrating peptides (CPPs) are capable of traversing this barrier without compromising membrane integrity, and they can do so on their own or coupled to cargos. Coupling biologically and medically relevant cargos to CPPs holds great promise of delivering membrane-impermeable drugs into cells. If the cargo is able to interact with certain cell types, uptake of the CPP–drug complex can be tailored to be cell-type-specific. Besides outlining the major membrane penetration pathways of CPPs, this review is aimed at deciphering how properties of the membrane influence the uptake mechanisms of CPPs. By summarizing an extensive body of experimental evidence, we argue that a more ordered, less flexible membrane structure, often present in the very diseases planned to be treated with CPPs, decreases their cellular uptake. These correlations are not only relevant for understanding the cellular biology of CPPs, but also for rationally improving their value in translational or clinical applications. LA - English DB - MTMT ER - TY - JOUR AU - Szántó, Gábor Tibor AU - Papp, Ferenc AU - Zákány, Florina AU - Varga, Zoltán AU - Deutsch, Carol AU - Panyi, György TI - Molecular rearrangements in S6 during slow inactivation in Shaker -IR potassium channels JF - JOURNAL OF GENERAL PHYSIOLOGY J2 - J GEN PHYSIOL VL - 155 PY - 2023 IS - 7 PG - 14 SN - 0022-1295 DO - 10.1085/jgp.202313352 UR - https://m2.mtmt.hu/api/publication/34007263 ID - 34007263 AB - Voltage-gated K+ channels have distinct gates that regulate ion flux: the activation gate (A-gate) formed by the bundle crossing of the S6 transmembrane helices and the slow inactivation gate in the selectivity filter. These two gates are bidirectionally coupled. If coupling involves the rearrangement of the S6 transmembrane segment, then we predict state-dependent changes in the accessibility of S6 residues from the water-filled cavity of the channel with gating. To test this, we engineered cysteines, one at a time, at S6 positions A471, L472, and P473 in a T449A Shaker-IR background and determined the accessibility of these cysteines to cysteine-modifying reagents MTSET and MTSEA applied to the cytosolic surface of inside-out patches. We found that neither reagent modified either of the cysteines in the closed or the open state of the channels. On the contrary, A471C and P473C, but not L472C, were modified by MTSEA, but not by MTSET, if applied to inactivated channels with open A-gate (OI state). Our results, combined with earlier studies reporting reduced accessibility of residues I470C and V474C in the inactivated state, strongly suggest that the coupling between the A-gate and the slow inactivation gate is mediated by rearrangements in the S6 segment. The S6 rearrangements are consistent with a rigid rod-like rotation of S6 around its longitudinal axis upon inactivation. S6 rotation and changes in its environment are concomitant events in slow inactivation of Shaker KV channels. LA - English DB - MTMT ER - TY - JOUR AU - Kovács, Tamás AU - Kurtan, Kitti AU - Varga, Zoltán AU - Nagy, Péter AU - Panyi, György AU - Zákány, Florina TI - Veklury® (remdesivir) formulations inhibit initial membrane‐coupled events of SARS‐CoV‐2 infection due to their sulfobutylether‐β‐cyclodextrin content JF - BRITISH JOURNAL OF PHARMACOLOGY J2 - BR J PHARMACOL VL - 180 PY - 2023 IS - 16 SP - 2064 EP - 2084 PG - 21 SN - 0007-1188 DO - 10.1111/bph.16063 UR - https://m2.mtmt.hu/api/publication/33671944 ID - 33671944 AB - Background and Purpose: Despite its contradictory clinical performance, remdesivir (Veklury®) has a pivotal role in COVID-19 therapy. Possible contributions of the vehicle, sulfobutylether-β-cyclodextrin (SBECD) to Veklury® effects have been overlooked. The powder and solution formulations of Veklury® are treated equivalently despite their different vehicle content. Our objective was to study Veklury® effects on initial membrane-coupled events of SARS-CoV-2 infection focusing on the cholesterol depletion-mediated role of SBECD. Experimental Approach: Using time-correlated flow cytometry and quantitative three-dimensional confocal microscopy, we studied early molecular events of SARS-CoV-2–host cell membrane interactions. Key Results: Veklury® and different cholesterol-depleting cyclodextrins (CDs) reduced binding of the spike receptor-binding domain (RBD) to ACE2 and spike trimer internalization for Wuhan-Hu-1, Delta and Omicron variants. Correlations of these effects with cholesterol-dependent changes in membrane structure and decreased lipid raft-dependent ACE2–TMPRSS2 interaction establish that SBECD is not simply a vehicle but also an effector along with remdesivir due to its cholesterol-depleting potential. Veklury® solution inhibited RBD binding more efficiently due to its twice higher SBECD content. The CD-induced inhibitory effects were more prominent at lower RBD concentrations and in cells with lower endogenous ACE2 expression, indicating that the supportive CD actions can be even more pronounced during in vivo infection when viral load and ACE expression are typically low. Conclusion and Implications: Our findings call for the differentiation of Veklury® formulations in meta-analyses of clinical trials, potentially revealing neglected benefits of the solution formulation, and also raise the possibility of adjuvant cyclodextrin (CD) therapy, even at higher doses, in COVID-19. LA - English DB - MTMT ER - TY - JOUR AU - Kovács, Tamás AU - Nagy, Péter AU - Panyi, György AU - Szente, Lajos AU - Varga, Zoltán AU - Zákány, Florina TI - Cyclodextrins: Only Pharmaceutical Excipients or Full-Fledged Drug Candidates? JF - PHARMACEUTICS J2 - PHARMACEUTICS VL - 14 PY - 2022 PG - 36 SN - 1999-4923 DO - 10.3390/pharmaceutics14122559 UR - https://m2.mtmt.hu/api/publication/33274154 ID - 33274154 N1 - Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, H-4032, Hungary CycloLab Cyclodextrin R & D Laboratory Ltd, Budapest, H-1097, Hungary Export Date: 2 March 2023 Correspondence Address: Zakany, F.; Department of Biophysics and Cell Biology, Hungary; email: florina.zakany@med.unideb.hu AB - Cyclodextrins, representing a versatile family of cyclic oligosaccharides, have extensive pharmaceutical applications due to their unique truncated cone-shaped structure with a hydrophilic outer surface and a hydrophobic cavity, which enables them to form non-covalent host–guest inclusion complexes in pharmaceutical formulations to enhance the solubility, stability and bioavailability of numerous drug molecules. As a result, cyclodextrins are mostly considered as inert carriers during their medical application, while their ability to interact not only with small molecules but also with lipids and proteins is largely neglected. By forming inclusion complexes with cholesterol, cyclodextrins deplete cholesterol from cellular membranes and thereby influence protein function indirectly through alterations in biophysical properties and lateral heterogeneity of bilayers. In this review, we summarize the general chemical principles of direct cyclodextrin–protein interactions and highlight, through relevant examples, how these interactions can modify protein functions in vivo, which, despite their huge potential, have been completely unexploited in therapy so far. Finally, we give a brief overview of disorders such as Niemann–Pick type C disease, atherosclerosis, Alzheimer’s and Parkinson’s disease, in which cyclodextrins already have or could have the potential to be active therapeutic agents due to their cholesterol-complexing or direct protein-targeting properties. LA - English DB - MTMT ER - TY - CHAP AU - Zákány, Florina AU - Kovács, Tamás AU - Szente, Lajos AU - Varga, Zoltán ED - Anna, N. Bukiya ED - Alex, M. Dopico TI - Cyclodextrins as promising therapeutics against cholesterol overload T2 - Cholesterol PB - Elsevier CY - Amsterdam SN - 9780323858588 PY - 2022 SP - 927 EP - 967 PG - 41 DO - 10.1016/B978-0-323-85857-1.00028-6 UR - https://m2.mtmt.hu/api/publication/32837794 ID - 32837794 N1 - Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary CycloLab Cyclodextrin R&D Laboratory Ltd., Budapest, Hungary Cited By :1 Export Date: 2 March 2023 LA - English DB - MTMT ER - TY - JOUR AU - Kovács, Tamás AU - Zákány, Florina AU - Nagy, Péter TI - It Takes More than Two to Tango: Complex, Hierarchal, and Membrane-Modulated Interactions in the Regulation of Receptor Tyrosine Kinases JF - CANCERS J2 - CANCERS VL - 14 PY - 2022 IS - 4 SP - 944 SN - 2072-6694 DO - 10.3390/cancers14040944 UR - https://m2.mtmt.hu/api/publication/32673363 ID - 32673363 N1 - Cited By :4 Export Date: 2 March 2023 Correspondence Address: Nagy, P.; Department of Biophysics and Cell Biology, Hungary; email: nagyp@med.unideb.hu LA - English DB - MTMT ER - TY - JOUR AU - Kovács, Tamás AU - Sohajda, Tamás AU - Szente, Lajos AU - Nagy, Péter AU - Panyi, György AU - Varga, Zoltán AU - Zákány, Florina TI - Cyclodextrins Exert a Ligand-like Current Inhibitory Effect on the KV1.3 Ion Channel Independent of Membrane Cholesterol Extraction JF - FRONTIERS IN MOLECULAR BIOSCIENCES J2 - FRONT MOL BIOSCI VL - 8 PY - 2021 SN - 2296-889X DO - 10.3389/fmolb.2021.735357 UR - https://m2.mtmt.hu/api/publication/32510829 ID - 32510829 N1 - Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary CycloLab Cyclodextrin R and D Laboratory Ltd, Budapest, Hungary Cited By :1 Export Date: 20 February 2022 Correspondence Address: Varga, Z.; Division of Biophysics, Hungary; email: veze@med.unideb.hu Correspondence Address: Zakany, F.; Division of Biophysics, Hungary; email: florina.zakany@med.unideb.hu LA - English DB - MTMT ER - TY - JOUR AU - Zákány, Florina AU - Szabó, Máté AU - Batta, Gyula Gábor (Ifj.) AU - Kárpáti, Levente AU - Mándity, István AU - Fülöp, Péter AU - Varga, Zoltán AU - Panyi, György AU - Nagy, Péter AU - Kovács, Tamás TI - An omega-3, but Not an omega-6 Polyunsaturated Fatty Acid Decreases Membrane Dipole Potential and Stimulates Endo-Lysosomal Escape of Penetratin JF - FRONTIERS IN CELL AND DEVELOPMENTAL BIOLOGY J2 - FRONT CELL DEV BIOL VL - 9 PY - 2021 PG - 17 SN - 2296-634X DO - 10.3389/fcell.2021.647300 UR - https://m2.mtmt.hu/api/publication/32219377 ID - 32219377 N1 - Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary Department of Genetics and Applied Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary Department of Organic Chemistry, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary Lendület-Artificial Chloride Ion Transporter Group, Institute of Materials and Environmental Chemistry, Research Center for Natural Sciences, Budapest, Hungary Division of Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary Cited By :7 Export Date: 2 March 2023 Correspondence Address: Kovacs, T.; Division of Biophysics, Hungary; email: kovacs.tamas@med.unideb.hu AB - Although the largely positive intramembrane dipole potential (DP) may substantially influence the function of transmembrane proteins, its investigation is deeply hampered by the lack of measurement techniques suitable for high-throughput examination of living cells. Here, we describe a novel emission ratiometric flow cytometry method based on F66, a 3-hydroxiflavon derivative, and demonstrate that 6-ketocholestanol, cholesterol and 7-dehydrocholesterol, saturated stearic acid (SA) and omega-6 gamma-linolenic acid (GLA) increase, while omega-3 alpha-linolenic acid (ALA) decreases the DP. These changes do not correlate with alterations in cell viability or membrane fluidity. Pretreatment with ALA counteracts, while SA or GLA enhances cholesterol-induced DP elevations. Furthermore, ALA (but not SA or GLA) increases endo-lysosomal escape of penetratin, a cell-penetrating peptide. In summary, we have developed a novel method to measure DP in large quantities of individual living cells and propose ALA as a physiological DP lowering agent facilitating cytoplasmic entry of penetratin. LA - English DB - MTMT ER -