Pub Date : 2025-06-01Epub Date: 2025-05-22DOI: 10.1016/j.bbamem.2025.184424
Evelyn A. Okorafor , Emma A. Gordon , Indra D. Sahu , Muhammad Zeeshan Shah , Dominik Konkolewicz , Gary A. Lorigan
Membrane bilayers are complex three-dimensional structures whose molecular events in the deep dimensions of membrane lipids are crucial for understanding membrane function. This study investigates the interaction of coexisting membrane domains in terms of hydrophobicity, alkyl chain order, and fluidity using Styrene Maleic Acid (SMA) copolymers as membrane mimics. We employed continuous wave electron paramagnetic resonance spectroscopy (CW-EPR) to characterize the structural dynamic properties of membrane domains without separation. Lipid-spin probe vesicles were prepared using phospholipids with varying degrees of saturation (DOPC, POPC, DMPC, and DSPC) and doxyl spin-labeled phospholipids at different depths (5, 12, and 16-doxyl PC) as membrane probes. These vesicles were titrated with two SMA polymers of different hydrophobic tail lengths. Dynamic light scattering (DLS) confirmed the formation of Styrene Maleic Acid lipid nanoparticles (SMALPs). CW-EPR spectroscopy was used to characterize the dynamic properties of vesicles incorporated into the SMALP systems. Analysis of the CW-EPR spectral line shape data revealed that the hydrophobic tail of SMA, the degree of lipid saturation, and the length of phospholipids significantly affect membrane fluidity and alkyl chain ordering, as well as lipid interactions. Notably, samples containing DSPC, a fully saturated longer-chain phospholipid, and those containing SMA exhibited increased rigidity of motion, reduced fluidity, and improved ordering of the alkyl chain in the membrane. This study provides crucial insights into the molecular dynamics of membrane bilayers and the impact of SMA copolymers on membrane properties, contributing to our understanding of fundamental membrane functions such as lateral movement of proteins and lipids.
{"title":"Influence of lipid saturation on the structural properties of styrene maleic acid lipid nanoparticles (SMALPs)","authors":"Evelyn A. Okorafor , Emma A. Gordon , Indra D. Sahu , Muhammad Zeeshan Shah , Dominik Konkolewicz , Gary A. Lorigan","doi":"10.1016/j.bbamem.2025.184424","DOIUrl":"10.1016/j.bbamem.2025.184424","url":null,"abstract":"<div><div>Membrane bilayers are complex three-dimensional structures whose molecular events in the deep dimensions of membrane lipids are crucial for understanding membrane function. This study investigates the interaction of coexisting membrane domains in terms of hydrophobicity, alkyl chain order, and fluidity using Styrene Maleic Acid (SMA) copolymers as membrane mimics. We employed continuous wave electron paramagnetic resonance spectroscopy (CW-EPR) to characterize the structural dynamic properties of membrane domains without separation. Lipid-spin probe vesicles were prepared using phospholipids with varying degrees of saturation (DOPC, POPC, DMPC, and DSPC) and doxyl spin-labeled phospholipids at different depths (5, 12, and 16-doxyl PC) as membrane probes. These vesicles were titrated with two SMA polymers of different hydrophobic tail lengths. Dynamic light scattering (DLS) confirmed the formation of Styrene Maleic Acid lipid nanoparticles (SMALPs). CW-EPR spectroscopy was used to characterize the dynamic properties of vesicles incorporated into the SMALP systems. Analysis of the CW-EPR spectral line shape data revealed that the hydrophobic tail of SMA, the degree of lipid saturation, and the length of phospholipids significantly affect membrane fluidity and alkyl chain ordering, as well as lipid interactions. Notably, samples containing DSPC, a fully saturated longer-chain phospholipid, and those containing SMA exhibited increased rigidity of motion, reduced fluidity, and improved ordering of the alkyl chain in the membrane. This study provides crucial insights into the molecular dynamics of membrane bilayers and the impact of SMA copolymers on membrane properties, contributing to our understanding of fundamental membrane functions such as lateral movement of proteins and lipids.</div></div>","PeriodicalId":8831,"journal":{"name":"Biochimica et biophysica acta. Biomembranes","volume":"1867 5","pages":"Article 184424"},"PeriodicalIF":2.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144141407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cholesterol (Chol) in mammalian cell membranes facilitates the assembly of dynamic membrane domains that are involved in vital biological processes through lateral and transbilayer movements in the membranes. In the cell membranes, Chol undergoes glucose transglycosylation to produce cholesteryl-β-d-glucoside (ChoGlc). ChoGlc is involved in neurodegenerative diseases and accumulates in lysosomal storage disorders. However, the effects of glucosylation on membrane properties of Chol remain unclear. We investigated the membrane interaction of ChoGlc and its subsequent translocation between leaflets using fluorescent probes, such as 4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH) and the newly synthesized 7-nitro-2,1,3-benzoxadiazole-labeled ChoGlc (NBD-ChoGlc) in dioleoylphosphatidylcholine (DOPC) membranes. The fluorescence of TMA-DPH, which selectively reported the order of the outer leaflet of the bilayer, indicated that ChoGlc added to the external solution, was mostly incorporated into the membranes and increased the DOPC membrane ordering. Furthermore, the anisotropy values reached a level similar to that of the ChoGlc-preloaded symmetric vesicle within approximately 5 min owing to the rapid distribution of ChoGlc in both leaflets. This was further confirmed by the selective fluorescence quenching of NBD-ChoGlc in the outer leaflet through irreversible quenching by dithionite. The similarity of the fluorescence decay curves of NBD-ChoGlc and NBD-Chol indicated that the glucosylation had little impact on the flip-flops of Chol in the DOPC bilayers. Our data demonstrates that some of the important membrane properties of Chol, such as fast flip-flop between leaflets and increased membrane order, were mostly maintained in ChoGlc despite hydrophilic glucose modification.
{"title":"Effect of glucosylation for the vertical movement of cholesterol in bilayer membranes","authors":"Shinya Hanashima , Takafumi Asahina , Raymond Malabed , Katsuaki Sasaki , Michio Murata","doi":"10.1016/j.bbamem.2025.184422","DOIUrl":"10.1016/j.bbamem.2025.184422","url":null,"abstract":"<div><div>Cholesterol (Chol) in mammalian cell membranes facilitates the assembly of dynamic membrane domains that are involved in vital biological processes through lateral and transbilayer movements in the membranes. In the cell membranes, Chol undergoes glucose transglycosylation to produce cholesteryl-β-<span>d</span>-glucoside (ChoGlc). ChoGlc is involved in neurodegenerative diseases and accumulates in lysosomal storage disorders. However, the effects of glucosylation on membrane properties of Chol remain unclear. We investigated the membrane interaction of ChoGlc and its subsequent translocation between leaflets using fluorescent probes, such as 4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH) and the newly synthesized 7-nitro-2,1,3-benzoxadiazole-labeled ChoGlc (NBD-ChoGlc) in dioleoylphosphatidylcholine (DOPC) membranes. The fluorescence of TMA-DPH, which selectively reported the order of the outer leaflet of the bilayer, indicated that ChoGlc added to the external solution, was mostly incorporated into the membranes and increased the DOPC membrane ordering. Furthermore, the anisotropy values reached a level similar to that of the ChoGlc-preloaded symmetric vesicle within approximately 5 min owing to the rapid distribution of ChoGlc in both leaflets. This was further confirmed by the selective fluorescence quenching of NBD-ChoGlc in the outer leaflet through irreversible quenching by dithionite. The similarity of the fluorescence decay curves of NBD-ChoGlc and NBD-Chol indicated that the glucosylation had little impact on the flip-flops of Chol in the DOPC bilayers. Our data demonstrates that some of the important membrane properties of Chol, such as fast flip-flop between leaflets and increased membrane order, were mostly maintained in ChoGlc despite hydrophilic glucose modification.</div></div>","PeriodicalId":8831,"journal":{"name":"Biochimica et biophysica acta. Biomembranes","volume":"1867 5","pages":"Article 184422"},"PeriodicalIF":2.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143918419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hinokitiol (β-thujaplicin) is a naturally occurring substance of antimicrobial properties, which can be used e.g. as a cosmetic preservative. In this work the influence of hinokitiol on the monolayers and bilayers formed from fungal membrane lipids (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine – POPE; 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine – POPC and ergosterol) was investigated. These studies aimed to investigate the effect of hinokitiol on fungal membranes, being indicated as a target for this compound. In this context, the affinity of hinokitiol for ergosterol-containing membranes was of particular interest. The in vitro antifungal activity of hinokitiol was also determined. The results showed that hinokitiol is active against the Candida species tested and exhibits stronger antifungal than antibacterial activity. Moreover, hinokitiol alters the properties of model membranes and the observed effects correlated with ergosterol content in the system. Namely, the higher the ergosterol content, the greater the fluidizing and destabilising effect of hinokitiol and its removal from the model. Moreover, hinokitiol is not able to penetrate into ergosterol membranes; instead, causes strong destabilization of the film and dragging the monolayer material into the subphase. Thus, hinokitiol changes properties of model membrane by the exclusion of the molecules from the interface. The results evidenced differences in the interactions of hinokitiol with ergosterol vs phospholipids, and the interactions of hinokitiol with the membrane depend on the presence and levels of ergosterol. Thus, ergosterol can be a molecular target for this compound. Moreover, the presence of ergosterol in fungal membranes and its lack in bacteria membranes may explain stronger antifungal vs antibacterial effect of hinokitiol.
{"title":"Interactions of hinokitiol with fungal membrane lipids in model systems","authors":"Beata Wyżga , Magdalena Skóra , Karolina Olechowska , Katarzyna Hąc-Wydro","doi":"10.1016/j.bbamem.2025.184423","DOIUrl":"10.1016/j.bbamem.2025.184423","url":null,"abstract":"<div><div>Hinokitiol (β-thujaplicin) is a naturally occurring substance of antimicrobial properties, which can be used e.g. as a cosmetic preservative. In this work the influence of hinokitiol on the monolayers and bilayers formed from fungal membrane lipids (1-palmitoyl-2-oleoyl-<em>sn</em>-glycero-3-phosphoethanolamine – POPE; 1-palmitoyl-2-oleoyl-<em>sn</em>-glycero-3-phosphocholine – POPC and ergosterol) was investigated. These studies aimed to investigate the effect of hinokitiol on fungal membranes, being indicated as a target for this compound. In this context, the affinity of hinokitiol for ergosterol-containing membranes was of particular interest. The in vitro antifungal activity of hinokitiol was also determined. The results showed that hinokitiol is active against the <em>Candida</em> species tested and exhibits stronger antifungal than antibacterial activity. Moreover, hinokitiol alters the properties of model membranes and the observed effects correlated with ergosterol content in the system. Namely, the higher the ergosterol content, the greater the fluidizing and destabilising effect of hinokitiol and its removal from the model. Moreover, hinokitiol is not able to penetrate into ergosterol membranes; instead, causes strong destabilization of the film and dragging the monolayer material into the subphase. Thus, hinokitiol changes properties of model membrane by the exclusion of the molecules from the interface. The results evidenced differences in the interactions of hinokitiol with ergosterol vs phospholipids, and the interactions of hinokitiol with the membrane depend on the presence and levels of ergosterol. Thus, ergosterol can be a molecular target for this compound. Moreover, the presence of ergosterol in fungal membranes and its lack in bacteria membranes may explain stronger antifungal vs antibacterial effect of hinokitiol.</div></div>","PeriodicalId":8831,"journal":{"name":"Biochimica et biophysica acta. Biomembranes","volume":"1867 5","pages":"Article 184423"},"PeriodicalIF":2.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01Epub Date: 2025-07-02DOI: 10.1016/j.bbamem.2025.184432
Lidia Ślusarczyk , Klaudia Rząd , Daniel Kamiński , Mariusz Gagoś , Małgorzata Figiel , Arkadiusz Matwijczuk
The paper presents the results of the first spectroscopic, microcalorimetric, and crystallographic study analyzing in great detail the strongly synergistic composition containing a selected 1,3,4-thiadiazole derivative: 4-(5-methyl-1,3,4-thiadiazol-2-ylo)benzene-1,3-diol (C1) and the antibiotic amphotericin B (AmB) in model biological DPPC films additionally modified with sterols: cholesterol (Chol) and ergosterol (Erg). The spectroscopic properties of the analyzed composition were studied with the use of spectroscopic methods, including: measurements of electronic fluorescence and absorption spectra with the technique of resonance light scattering (RLS), measurements of stationary fluorescence anisotropy and time-resolved fluorescence lifetimes with the method of single photon counting (TCSPC), circular dichroism spectra (CD), and infrared FTIR spectra. The mentioned methods were further complemented by including microcalorimetric DSC and crystallographic XRD analyses. All the measurements were taken in model biological systems formed as liposomal films and liposomal multilayers composed of DPPC and/or modified with sterols: cholesterol and ergosterol. The absorption spectra measured for C1/AmB and the synergistic composition thereof revealed differences indicating that while the antibiotic forms retained its known tendency to form aggregate in film systems, the synergistic composition had certain effects on the aggregational equilibrium. This was also reflected in the fluorescence emission measured for said systems, in particular the RLS and CD spectra, as well as, to an extent, the results of fluorescence anisotropy measurements. As we proceeded to the analysis of FTIR spectra, it was observed that the synergistic composition of C1 + AmB showed stronger interaction with the hydrophobic layer of the film. In turn, the crystallographic measurements performed for the synergistic composition revealed its impact on the multilayer's thickness. Finally, microcalorimetric measurements indicated that the synergistic composition had a lesser impact on the main phase transition temperature of the lipid, as compared to the respective compounds tested separately. The presented paper is the most detailed report to date pertaining to the synergism observed for the relevant systems analyzed in model biological films modified with sterols.
The study provides an in-depth spectroscopic, microcalorimetric, and crystallographic description of the molecular interactions analyzed for said molecular systems in model films formed of DPPC with the addition of sterols. Its results are particularly significant given the fact that AmB continues to be a clinically relevant antibiotic employed in the treatment of particularly severe internal mycoses and against otherwise resistant fungal strains.
{"title":"An advanced spectroscopic and crystallographic study on a synergistic composition of a 1,3,4-thiadiazole derivative and amphotericin B, in model biological liposomal system","authors":"Lidia Ślusarczyk , Klaudia Rząd , Daniel Kamiński , Mariusz Gagoś , Małgorzata Figiel , Arkadiusz Matwijczuk","doi":"10.1016/j.bbamem.2025.184432","DOIUrl":"10.1016/j.bbamem.2025.184432","url":null,"abstract":"<div><div>The paper presents the results of the first spectroscopic, microcalorimetric, and crystallographic study analyzing in great detail the strongly synergistic composition containing a selected <em>1,3,4</em>-thiadiazole derivative: <em>4-</em>(<em>5-methyl-1,3,4-thiadiazol-2-ylo</em>)<em>benzene-1,3-diol</em> (<strong>C1</strong>) and the antibiotic amphotericin B (<strong>AmB</strong>) in model biological DPPC films additionally modified with sterols: cholesterol (<strong>Chol</strong>) and ergosterol (<strong>Erg</strong>). The spectroscopic properties of the analyzed composition were studied with the use of spectroscopic methods, including: measurements of electronic fluorescence and absorption spectra with the technique of resonance light scattering (RLS), measurements of stationary fluorescence anisotropy and time-resolved fluorescence lifetimes with the method of single photon counting (TCSPC), circular dichroism spectra (CD), and infrared FTIR spectra. The mentioned methods were further complemented by including microcalorimetric DSC and crystallographic XRD analyses. All the measurements were taken in model biological systems formed as liposomal films and liposomal multilayers composed of DPPC and/or modified with sterols: cholesterol and ergosterol. The absorption spectra measured for C1/AmB and the synergistic composition thereof revealed differences indicating that while the antibiotic forms retained its known tendency to form aggregate in film systems, the synergistic composition had certain effects on the aggregational equilibrium. This was also reflected in the fluorescence emission measured for said systems, in particular the RLS and CD spectra, as well as, to an extent, the results of fluorescence anisotropy measurements. As we proceeded to the analysis of FTIR spectra, it was observed that the synergistic composition of C1 + AmB showed stronger interaction with the hydrophobic layer of the film. In turn, the crystallographic measurements performed for the synergistic composition revealed its impact on the multilayer's thickness. Finally, microcalorimetric measurements indicated that the synergistic composition had a lesser impact on the main phase transition temperature of the lipid, as compared to the respective compounds tested separately. The presented paper is the most detailed report to date pertaining to the synergism observed for the relevant systems analyzed in model biological films modified with sterols.</div><div>The study provides an in-depth spectroscopic, microcalorimetric, and crystallographic description of the molecular interactions analyzed for said molecular systems in model films formed of DPPC with the addition of sterols. Its results are particularly significant given the fact that AmB continues to be a clinically relevant antibiotic employed in the treatment of particularly severe internal mycoses and against otherwise resistant fungal strains.</div></div>","PeriodicalId":8831,"journal":{"name":"Biochimica et biophysica acta. Biomembranes","volume":"1867 5","pages":"Article 184432"},"PeriodicalIF":2.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144534809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
TRPV5 and TRPV6 are members of the TRP superfamily of ion channels and are present in almost all vertebrates as linked-genes with high homology and functional similarities. Abnormalities in the regulation or function of these two channels cause multiple pathological conditions, making these highly relevant for several diseases and pharmacological applications. In this context, how these two channels differ from each other is largely unknown. Here we analysed ∼250 protein sequences from vertebrates and critically analysed the conservation of signature motifs, such as different domains, TM-regions, loop-regions, cholesterol-binding regions and lipid-water-interface (LWI) regions. We demonstrate the subtle differences in the motifs and residues that are present at the LWI in TRPV5 and TRPV6. The ratio of hydrophobic-to-hydrophilic residues (but not of positive-to-negative residues) remains conserved for TRPV5 and TRPV6 throughout the vertebrate evolution. We also found motifs where cholesterol and/or sphingolipid can interact with TRPV5 and TRPV6 yet with different energies, both in open- and close-conformation. Accordingly, experimental evidence suggest that partial depletion of membrane cholesterol lowers the agonist-mediated opening of TRPV6, confirming the importance of membrane cholesterol for channel function. Further analysis of somatic mutations suggests that the specific inner LWI regions of TRPV5 (first 3) and TRPV6 (first 5) impose mutational hot-spots that are linked with different cancers. These findings may have broad significance in designing pharmacological agents for targeting TRPV5 and TRPV6 separately or simultaneously.
{"title":"Amino acids critical for lipid/s-interaction at the lipid-water-interface of TRPV5/TRPV6 remain different during vertebrate radiation: Relevance in cancer, bone disorders and other pathophysiologies","authors":"Sweta Agarwal , Vikash Kumar , Anupriya Chattapadhya , Shamit Kumar , Luna Goswami , Chandan Goswami","doi":"10.1016/j.bbamem.2025.184433","DOIUrl":"10.1016/j.bbamem.2025.184433","url":null,"abstract":"<div><div>TRPV5 and TRPV6 are members of the TRP superfamily of ion channels and are present in almost all vertebrates as linked-genes with high homology and functional similarities. Abnormalities in the regulation or function of these two channels cause multiple pathological conditions, making these highly relevant for several diseases and pharmacological applications. In this context, how these two channels differ from each other is largely unknown. Here we analysed ∼250 protein sequences from vertebrates and critically analysed the conservation of signature motifs, such as different domains, TM-regions, loop-regions, cholesterol-binding regions and lipid-water-interface (LWI) regions. We demonstrate the subtle differences in the motifs and residues that are present at the LWI in TRPV5 and TRPV6. The ratio of hydrophobic-to-hydrophilic residues (but not of positive-to-negative residues) remains conserved for TRPV5 and TRPV6 throughout the vertebrate evolution. We also found motifs where cholesterol and/or sphingolipid can interact with TRPV5 and TRPV6 yet with different energies, both in open- and close-conformation. Accordingly, experimental evidence suggest that partial depletion of membrane cholesterol lowers the agonist-mediated opening of TRPV6, confirming the importance of membrane cholesterol for channel function. Further analysis of somatic mutations suggests that the specific inner LWI regions of TRPV5 (first 3) and TRPV6 (first 5) impose mutational hot-spots that are linked with different cancers. These findings may have broad significance in designing pharmacological agents for targeting TRPV5 and TRPV6 separately or simultaneously.</div></div>","PeriodicalId":8831,"journal":{"name":"Biochimica et biophysica acta. Biomembranes","volume":"1867 5","pages":"Article 184433"},"PeriodicalIF":2.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144551838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01Epub Date: 2025-05-21DOI: 10.1016/j.bbamem.2025.184425
Misuzu Ueki , Takahisa Maki , Masayuki Iwamoto
Cell membranes regulate water flow to maintain homeostasis, cell volume, and osmotic balance. Aquaporins (AQPs) enable selective water transport, making precise permeability measurements essential for understanding their function. The current methods have limitations, including high resource demands and poor control over membrane properties like bilayer tension. In this study, the droplet interface bilayer (DIB) system was used to measure aquaporin water channel activity. Unlike conventional water permeability assays, this method uniquely quantifies lipid bilayer tension by determining droplet internal pressure. This pressure-determined DIB (PDIB) method was used to investigate the water permeability of a lipid bilayer reconstituted with Escherichia coli aquaporin Z (AqpZ). Water permeability increased in an AqpZ concentration-dependent manner at bilayer tensions of 2.2–3.0 mN/m and was inhibited by mercury (IC50, 340 μM). Fluorescence microscopy was performed to visualize and quantify AqpZ molecules, thereby allowing us to derive an approximate estimate of the unitary water permeability. Although this study established the PDIB method and demonstrated its applicability to AqpZ, this technique may also facilitate future investigations on the effects of lipid bilayer tension on aquaporin function and the fundamental mechanisms of water transport across biological membranes.
{"title":"Evaluation of aquaporin Z water permeability in bilayers using droplet interface systems with internal-pressure–defined membrane tension","authors":"Misuzu Ueki , Takahisa Maki , Masayuki Iwamoto","doi":"10.1016/j.bbamem.2025.184425","DOIUrl":"10.1016/j.bbamem.2025.184425","url":null,"abstract":"<div><div>Cell membranes regulate water flow to maintain homeostasis, cell volume, and osmotic balance. Aquaporins (AQPs) enable selective water transport, making precise permeability measurements essential for understanding their function. The current methods have limitations, including high resource demands and poor control over membrane properties like bilayer tension. In this study, the droplet interface bilayer (DIB) system was used to measure aquaporin water channel activity. Unlike conventional water permeability assays, this method uniquely quantifies lipid bilayer tension by determining droplet internal pressure. This pressure-determined DIB (PDIB) method was used to investigate the water permeability of a lipid bilayer reconstituted with <em>Escherichia coli</em> aquaporin Z (AqpZ). Water permeability increased in an AqpZ concentration-dependent manner at bilayer tensions of 2.2–3.0 mN/m and was inhibited by mercury (IC<sub>50</sub>, 340 μM). Fluorescence microscopy was performed to visualize and quantify AqpZ molecules, thereby allowing us to derive an approximate estimate of the unitary water permeability. Although this study established the PDIB method and demonstrated its applicability to AqpZ, this technique may also facilitate future investigations on the effects of lipid bilayer tension on aquaporin function and the fundamental mechanisms of water transport across biological membranes.</div></div>","PeriodicalId":8831,"journal":{"name":"Biochimica et biophysica acta. Biomembranes","volume":"1867 5","pages":"Article 184425"},"PeriodicalIF":2.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144115070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01Epub Date: 2025-06-07DOI: 10.1016/j.bbamem.2025.184429
Vanessa Gallego-Londoño , Gloria A. Santa-González , Juan M. Giraldo-Lorza , Mauricio Rojas , G. Bea A. Wisman , Steven de Jong , Marcela Manrique-Moreno
Cationic peptides offer a promising alternative for cancer treatment due to their ability to target cancer cells via standard membrane features, thereby overcoming intratumoral heterogeneity. This study investigates the cytotoxic activity and the membrane-disruptive effects of two snake venom-derived peptides, Crotalicidin (Ctn) and NA-CATH-ATRA-1-ATRA-1 (NA) in human breast cancer cells. Cell viability assays showed that both Ctn and NA significantly diminished the viability of MCF-7 and MDA-MB-231 cells, with NA showing greater potency, as indicated by lower IC50 values of 13.4 μM for MCF-7 and 6.4 μM for MDA-MB-231. Microscopy and flow cytometry revealed size reduction and increased granularity in treated cells. Further analyses indicated that the peptides induced membrane permeabilization, as evidenced by significant propidium iodide uptake, without significantly altering mitochondrial membrane potential. Apoptosis markers such as cleaved caspase-9 and PARP, were not detected by western blot.
Additionally, LDH release and confocal microscopic analysis supported the findings of membrane disruption. Finally, infrared spectroscopy (FT-IR) on lipid extracts revealed peptide-membrane interactions, resulting in phase transitions consistent with membrane disruption. These findings highlight the potent cytotoxic effects of Ctn and NA on breast cancer cells and their potential as novel therapeutic agents.
{"title":"Crotalicidin and NA-CATH-ATRA-1-ATRA-1 peptide-induced membrane disruption in human breast cancer cells","authors":"Vanessa Gallego-Londoño , Gloria A. Santa-González , Juan M. Giraldo-Lorza , Mauricio Rojas , G. Bea A. Wisman , Steven de Jong , Marcela Manrique-Moreno","doi":"10.1016/j.bbamem.2025.184429","DOIUrl":"10.1016/j.bbamem.2025.184429","url":null,"abstract":"<div><div>Cationic peptides offer a promising alternative for cancer treatment due to their ability to target cancer cells via standard membrane features, thereby overcoming intratumoral heterogeneity. This study investigates the cytotoxic activity and the membrane-disruptive effects of two snake venom-derived peptides, Crotalicidin (Ctn) and NA-CATH-ATRA-1-ATRA-1 (NA) in human breast cancer cells. Cell viability assays showed that both Ctn and NA significantly diminished the viability of MCF-7 and MDA-MB-231 cells, with NA showing greater potency, as indicated by lower IC<sub>50</sub> values of 13.4 μM for MCF-7 and 6.4 μM for MDA-MB-231. Microscopy and flow cytometry revealed size reduction and increased granularity in treated cells. Further analyses indicated that the peptides induced membrane permeabilization, as evidenced by significant propidium iodide uptake, without significantly altering mitochondrial membrane potential. Apoptosis markers such as cleaved caspase-9 and PARP, were not detected by western blot.</div><div>Additionally, LDH release and confocal microscopic analysis supported the findings of membrane disruption. Finally, infrared spectroscopy (FT-IR) on lipid extracts revealed peptide-membrane interactions, resulting in phase transitions consistent with membrane disruption. These findings highlight the potent cytotoxic effects of Ctn and NA on breast cancer cells and their potential as novel therapeutic agents.</div></div>","PeriodicalId":8831,"journal":{"name":"Biochimica et biophysica acta. Biomembranes","volume":"1867 5","pages":"Article 184429"},"PeriodicalIF":2.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144257297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01Epub Date: 2025-06-19DOI: 10.1016/j.bbamem.2025.184431
Justyna Kapral-Piotrowska , Agata Wawrzyniak , Jarosław Pawelec , Barbara Zarzyka , Roman Paduch , Jerzy Żuchowski , Adrianna Sławińska-Brych , Barbara Zdzisińska , Bartłomiej Pawlęga , Alicja Wójcik-Załuska , Ewa Baranowska-Wójcik , Joanna Jakubowicz-Gil , Wiesław I. Gruszecki , Bożena Pawlikowska-Pawlęga
Lensoside Aβ (LAβ) is a quercetin derivative isolated from the leaves and stems of the Lens culinaris cultivar Tina. Flavonoid-membrane interactions are crucial for their physiological and pharmacological activity. We have demonstrated the impact of LAβ on EYPC liposomes resembling the lipid phase of tumor cell membranes with the use of the 1H NMR technique and have examined its activity on HeLa cells for the first time. To study the interactions of the tested compound with lipids and proteins at the molecular level, the FTIR technique was applied. To reveal changes in morphology and ultrastructure as well as examine its effect on apoptosis induction and cell viability, SEM, TEM, light, and fluorescence microscopy, flow cytometry analysis, LIVE/DEAD assays were employed. The ability of LAβ to induce oxidative stress was determined by staining with DHR123. The FTIR analyses indicated that LAβ interacts with the PO2− groups in the polar head region. Moreover, a decrease in the relative protein concentration and changes in protein spectral profile in the amide I region were noted. Flavonoid reduced the viability of HeLa cells, which was correlated with the induction of apoptosis supported by SEM and TEM observations. Moreover, the addition of lensoside Aβ induced oxidative stress. These results confirm that lensoside Aβ may be used in novel therapeutic approaches for treating cervical cancer.
Lensoside a β (LAβ)是一种槲皮素衍生物,从植物天娜(Tina)的叶和茎中分离得到。黄酮类化合物与膜的相互作用对其生理和药理活性至关重要。我们利用1H NMR技术证明了LAβ对类似肿瘤细胞膜脂质期的EYPC脂质体的影响,并首次检测了其对HeLa细胞的活性。为了在分子水平上研究被测化合物与脂质和蛋白质的相互作用,应用了FTIR技术。采用扫描电镜(SEM)、透射电镜(TEM)、荧光显微镜(light and fluorescence microscopy)、流式细胞术(flow cytometry)、LIVE/DEAD等方法观察其形态学和超微结构的变化以及对细胞凋亡诱导和细胞活力的影响。DHR123染色法测定LAβ诱导氧化应激的能力。FTIR分析表明,LAβ与极性头区PO2 -基团相互作用。此外,还发现了相对蛋白浓度的降低和酰胺I区蛋白谱的变化。SEM和TEM观察显示,黄酮类化合物降低HeLa细胞活力与诱导凋亡有关。此外,晶状体皂苷Aβ的加入诱导了氧化应激。这些结果证实了透镜糖苷Aβ可能用于治疗宫颈癌的新方法。
{"title":"Interaction of lensoside Aβ with lipids and proteins of HeLa cells","authors":"Justyna Kapral-Piotrowska , Agata Wawrzyniak , Jarosław Pawelec , Barbara Zarzyka , Roman Paduch , Jerzy Żuchowski , Adrianna Sławińska-Brych , Barbara Zdzisińska , Bartłomiej Pawlęga , Alicja Wójcik-Załuska , Ewa Baranowska-Wójcik , Joanna Jakubowicz-Gil , Wiesław I. Gruszecki , Bożena Pawlikowska-Pawlęga","doi":"10.1016/j.bbamem.2025.184431","DOIUrl":"10.1016/j.bbamem.2025.184431","url":null,"abstract":"<div><div>Lensoside Aβ (LAβ) is a quercetin derivative isolated from the leaves and stems of the <em>Lens culinaris</em> cultivar Tina. Flavonoid-membrane interactions are crucial for their physiological and pharmacological activity. We have demonstrated the impact of LAβ on EYPC liposomes resembling the lipid phase of tumor cell membranes with the use of the <sup>1</sup>H NMR technique and have examined its activity on HeLa cells for the first time. To study the interactions of the tested compound with lipids and proteins at the molecular level, the FTIR technique was applied. To reveal changes in morphology and ultrastructure as well as examine its effect on apoptosis induction and cell viability, SEM, TEM, light, and fluorescence microscopy, flow cytometry analysis, LIVE/DEAD assays were employed. The ability of LAβ to induce oxidative stress was determined by staining with DHR123. The FTIR analyses indicated that LAβ interacts with the PO<sub>2</sub><sub>−</sub> groups in the polar head region. Moreover, a decrease in the relative protein concentration and changes in protein spectral profile in the amide I region were noted. Flavonoid reduced the viability of HeLa cells, which was correlated with the induction of apoptosis supported by SEM and TEM observations. Moreover, the addition of lensoside Aβ induced oxidative stress. These results confirm that lensoside Aβ may be used in novel therapeutic approaches for treating cervical cancer.</div></div>","PeriodicalId":8831,"journal":{"name":"Biochimica et biophysica acta. Biomembranes","volume":"1867 5","pages":"Article 184431"},"PeriodicalIF":2.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144330690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01Epub Date: 2025-05-23DOI: 10.1016/j.bbamem.2025.184426
Valeriya Trusova, Uliana Malovytsia, Kateryna Vus, Olga Zhytniakivska, Galyna Gorbenko
The feasibility of engineering the sophisticated hybrid drug delivery platforms through the integration of phospholipid vesicles within a matrix of amyloid suspensions has been evaluated. Utilizing the equilibrium dialysis methodology and spectrofluorometric technique, the quantitative analysis of doxorubicin (DOX) encapsulation capacity of diverse phospholipid assemblies, amyloid suspensions, and their corresponding composite systems has been performed. Our findings revealed that the incorporation of negatively charged cardiolipin (CL) into phosphatidylcholine (PC) lipid vesicles significantly enhances DOX encapsulation and retention, while the addition of amyloid fibrils to charged liposomes has minimal impact on the drug binding. The neutral PC liposomes modified with insulin and lysozyme fibrillar suspensions exhibited improved doxorubicin encapsulation and retention compared to unmodified liposomes, thereby displaying a potential for reduced toxicity and prolonged drug action in vivo. Notably, amyloid fibrils alone were found to demonstrate the lower degree of DOX encapsulation and retention as compared to liposomes. Fluorimetric analysis suggests that the presence of insulin and lysozyme fibrils alters the microenvironment of DOX towards a more hydrophobic which is consistent with deeper bilayer penetration. Cumulative data from release kinetics and retention studies along with fluorescence measurements suggest that PC liposome-insulin fibril composites represent the most promising DOX nanocarriers, combining enhanced drug encapsulation, structural stability, and optimal drug location within the bilayer. The results obtained provide valuable insights into the design of protein-lipid nanomaterials for enhanced drug delivery, offering promising avenues for the development of more effective and targeted therapeutic strategies.
{"title":"Amyloid-liposome composites as hybrid platforms for doxorubicin delivery","authors":"Valeriya Trusova, Uliana Malovytsia, Kateryna Vus, Olga Zhytniakivska, Galyna Gorbenko","doi":"10.1016/j.bbamem.2025.184426","DOIUrl":"10.1016/j.bbamem.2025.184426","url":null,"abstract":"<div><div>The feasibility of engineering the sophisticated hybrid drug delivery platforms through the integration of phospholipid vesicles within a matrix of amyloid suspensions has been evaluated. Utilizing the equilibrium dialysis methodology and spectrofluorometric technique, the quantitative analysis of doxorubicin (DOX) encapsulation capacity of diverse phospholipid assemblies, amyloid suspensions, and their corresponding composite systems has been performed. Our findings revealed that the incorporation of negatively charged cardiolipin (CL) into phosphatidylcholine (PC) lipid vesicles significantly enhances DOX encapsulation and retention, while the addition of amyloid fibrils to charged liposomes has minimal impact on the drug binding. The neutral PC liposomes modified with insulin and lysozyme fibrillar suspensions exhibited improved doxorubicin encapsulation and retention compared to unmodified liposomes, thereby displaying a potential for reduced toxicity and prolonged drug action <em>in vivo</em>. Notably, amyloid fibrils alone were found to demonstrate the lower degree of DOX encapsulation and retention as compared to liposomes. Fluorimetric analysis suggests that the presence of insulin and lysozyme fibrils alters the microenvironment of DOX towards a more hydrophobic which is consistent with deeper bilayer penetration. Cumulative data from release kinetics and retention studies along with fluorescence measurements suggest that PC liposome-insulin fibril composites represent the most promising DOX nanocarriers, combining enhanced drug encapsulation, structural stability, and optimal drug location within the bilayer. The results obtained provide valuable insights into the design of protein-lipid nanomaterials for enhanced drug delivery, offering promising avenues for the development of more effective and targeted therapeutic strategies.</div></div>","PeriodicalId":8831,"journal":{"name":"Biochimica et biophysica acta. Biomembranes","volume":"1867 5","pages":"Article 184426"},"PeriodicalIF":2.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01Epub Date: 2025-06-17DOI: 10.1016/j.bbamem.2025.184430
Veronika Osten , Dirk Schneider
The structure and the function of membrane proteins can be affected by the lipid bilayer environment, yet its impact is often neglected in in vitro studies where proteins are typically analyzed in membrane mimetics, mostly liposomal systems. It has been observed that the activity of the bacterial ATP-binding cassette (ABC) transporter BmrA (Bacillus multidrug resistance ATP) differs when measured in detergent vs. a model membrane environment, indicating that the physico-chemical properties of the membrane environment crucially affect the protein's activity. We now performed a systematic analysis to elucidate the impact of individual lipid/membrane properties on the activity of BmrA and identified three parameters controlling the BmrA activity in lipid bilayers: (i) the hydrophobic thickness of the membrane, (ii) a negative surface charge, and (iii) the packing of lipids in the acyl-chain and head group regions. Our study provides valuable insights into how a specific lipid composition can influence the basal ATPase activity of BmrA and emphasizes that the lipid composition should be carefully selected in in vitro studies of membrane proteins.
{"title":"Membrane properties control the ATPase activity of the ABC transporter BmrA","authors":"Veronika Osten , Dirk Schneider","doi":"10.1016/j.bbamem.2025.184430","DOIUrl":"10.1016/j.bbamem.2025.184430","url":null,"abstract":"<div><div>The structure and the function of membrane proteins can be affected by the lipid bilayer environment, yet its impact is often neglected in <em>in vitro</em> studies where proteins are typically analyzed in membrane mimetics, mostly liposomal systems. It has been observed that the activity of the bacterial ATP-binding cassette (ABC) transporter BmrA (<em>Bacillus</em> multidrug resistance ATP) differs when measured in detergent <em>vs.</em> a model membrane environment, indicating that the physico-chemical properties of the membrane environment crucially affect the protein's activity. We now performed a systematic analysis to elucidate the impact of individual lipid/membrane properties on the activity of BmrA and identified three parameters controlling the BmrA activity in lipid bilayers: (i) the hydrophobic thickness of the membrane, (ii) a negative surface charge, and (iii) the packing of lipids in the acyl-chain and head group regions. Our study provides valuable insights into how a specific lipid composition can influence the basal ATPase activity of BmrA and emphasizes that the lipid composition should be carefully selected in <em>in vitro</em> studies of membrane proteins.</div></div>","PeriodicalId":8831,"journal":{"name":"Biochimica et biophysica acta. Biomembranes","volume":"1867 5","pages":"Article 184430"},"PeriodicalIF":2.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144322078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}