Correlating biological activity to thermo-structural analysis of the interaction of CTX with synthetic models of macrophage membranes

AbstractThe important pharmacological actions of Crotoxin (CTX) on macrophages, the main toxin in the venom of Crotalus durissus terrificus, and its important participation in the control of different pathophysiological processes, have been demonstrated. The biological activities performed by macrophages are related to signaling mediated by receptors expressed on the membrane surface of these cells or opening and closing of ion channels, generation of membrane curvature and pore formation. In the present work, the interaction of the CTX complex with the cell membrane of macrophages is studied, both using biological cells and synthetic lipid membranes to monitor structural alterations induced by the protein. Here we show that CTX can penetrate THP-1 cells and induce pores only in anionic lipid model membranes, suggesting that a possible access pathway for CTX to the cell is via lipids with anionic polar heads. Considering that the selectivity of the lipid composition varies in different tissues and organs of the human body, the thermostructural studies presented here are extremely important to open new investigations on the biological activities of CTX in different biological systems.

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Single Vesicle Analysis Reveals Nanoscale Membrane Curvature Selective Pore Formation in Lipid Membranes by an Antiviral α-Helical Peptide

Nano Letters ◽

10.1021/nl3029637 ◽

2012 ◽

Vol 12 (11) ◽

pp. 5719-5725 ◽

Cited By ~ 42

Author(s):

Seyed R. Tabaei ◽

Michael Rabe ◽

Vladimir P. Zhdanov ◽

Nam-Joon Cho ◽

Fredrik Höök

Keyword(s):

Lipid Membranes ◽

Pore Formation ◽

Membrane Curvature ◽

Helical Peptide ◽

Single Vesicle

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Induction of Highly Curved Structures in Relation to Membrane Permeabilization and Budding by the Triterpenoid Saponins, α- and δ-Hederin

Journal of Biological Chemistry ◽

10.1074/jbc.m112.407635 ◽

2013 ◽

Vol 288 (20) ◽

pp. 14000-14017 ◽

Cited By ~ 34

Author(s):

Joseph Lorent ◽

Cécile S. Le Duff ◽

Joelle Quetin-Leclercq ◽

Marie-Paule Mingeot-Leclercq

Keyword(s):

Lipid Membranes ◽

Pore Formation ◽

Lateral Diffusion ◽

Molecular Shape ◽

Membrane Curvature ◽

Membrane Permeabilization ◽

Spontaneous Curvature ◽

Unilamellar Vesicles ◽

Generalized Polarization ◽

Triterpenoid Saponins

The interactions of triterpenoid monodesmosidic saponins, α-hederin and δ-hederin, with lipid membranes are involved in their permeabilizing effect. Unfortunately, the interactions of these saponins with lipid membranes are largely unknown, as are the roles of cholesterol or the branched sugar moieties (two for α-hederin and one for δ-hederin) on the aglycone backbone, hederagenin. The differences in sugar moieties are responsible for differences in the molecular shape of the saponins and the effects on membrane curvature that should be the most positive for α-hederin in a transbilayer direction. In large unilamellar vesicles and monocyte cells, we showed that membrane permeabilization was dependent on the presence of membrane cholesterol and saponin sugar chains, being largest for α-hederin and smallest for hederagenin. In the presence of cholesterol, α-hederin induced the formation of nonbilayer phases with a higher rate of Brownian tumbling or lateral diffusion. A reduction of Laurdan's generalized polarization in relation to change in order of the polar heads of phospholipids was observed. Using giant unilamellar vesicles, we visualized the formation of wrinkled borders, the decrease in liposome size, budding, and the formation of macroscopic pores. All these processes are highly dependent on the sugars linked to the aglycone, with α-hederin showing a greater ability to induce pore formation and δ-hederin being more efficient in inducing budding. Hederagenin induced intravesicular budding but no pore formation. Based on these results, a curvature-driven permeabilization mechanism dependent on the interaction between saponin and sterols and on the molecular shape of the saponin and its ability to induce local spontaneous curvature is proposed.

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Cardiolipin-Containing Lipid Membranes Attract the Bacterial Cell Division Protein DivIVA

International Journal of Molecular Sciences ◽

10.3390/ijms22158350 ◽

2021 ◽

Vol 22 (15) ◽

pp. 8350

Author(s):

Naďa Labajová ◽

Natalia Baranova ◽

Miroslav Jurásek ◽

Robert Vácha ◽

Martin Loose ◽

...

Keyword(s):

Cell Division ◽

Lipid Bilayers ◽

Bacterial Cell ◽

Lipid Membranes ◽

Model Organism ◽

Active Role ◽

Membrane Curvature ◽

Bacterial Cell Division ◽

Division Site ◽

Clostridioides Difficile

DivIVA is a protein initially identified as a spatial regulator of cell division in the model organism Bacillus subtilis, but its homologues are present in many other Gram-positive bacteria, including Clostridia species. Besides its role as topological regulator of the Min system during bacterial cell division, DivIVA is involved in chromosome segregation during sporulation, genetic competence, and cell wall synthesis. DivIVA localizes to regions of high membrane curvature, such as the cell poles and cell division site, where it recruits distinct binding partners. Previously, it was suggested that negative curvature sensing is the main mechanism by which DivIVA binds to these specific regions. Here, we show that Clostridioides difficile DivIVA binds preferably to membranes containing negatively charged phospholipids, especially cardiolipin. Strikingly, we observed that upon binding, DivIVA modifies the lipid distribution and induces changes to lipid bilayers containing cardiolipin. Our observations indicate that DivIVA might play a more complex and so far unknown active role during the formation of the cell division septal membrane.

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Naphthalimide-Containing BP100 Leads to Higher Model Membranes Interactions and Antimicrobial Activity

Biomolecules ◽

10.3390/biom11040542 ◽

2021 ◽

Vol 11 (4) ◽

pp. 542

Author(s):

Gustavo Penteado Battesini Carretero ◽

Greice Kelle Viegas Saraiva ◽

Magali Aparecida Rodrigues ◽

Sumika Kiyota ◽

Marcelo Porto Bemquerer ◽

...

Keyword(s):

Anticancer Agents ◽

Biological Activities ◽

Biological Effects ◽

Membrane Surface ◽

Helical Structure ◽

Helical Conformation ◽

Property A ◽

Cellular Processes ◽

Double Stranded Dna ◽

Low Toxicity

In a large variety of organisms, antimicrobial peptides (AMPs) are primary defenses against pathogens. BP100 (KKLFKKILKYL-NH2), a short, synthetic, cationic AMP, is active against bacteria and displays low toxicity towards eukaryotic cells. BP100 acquires a α-helical conformation upon interaction with membranes and increases membrane permeability. Despite the volume of information available, the action mechanism of BP100, the selectivity of its biological effects, and possible applications are far from consensual. Our group synthesized a fluorescent BP100 analogue containing naphthalimide linked to its N-terminal end, NAPHT-BP100 (Naphthalimide-AAKKLFKKILKYL-NH2). The fluorescence properties of naphthalimides, especially their spectral sensitivity to microenvironment changes, are well established, and their biological activities against transformed cells and bacteria are known. Naphthalimide derived compounds are known to interact with DNA disturbing related processes as replication and transcription, and used as anticancer agents due to this property. A wide variety of techniques were used to demonstrate that NAPHT-BP100 bound to and permeabilized zwitterionic POPC and negatively charged POPC:POPG liposomes and, upon interaction, acquired a α-helical structure. Membrane surface high peptide/lipid ratios triggered complete permeabilization of the liposomes in a detergent-like manner. Membrane disruption was driven by charge neutralization, lipid aggregation, and bilayer destabilization. NAPHT-BP100 also interacted with double-stranded DNA, indicating that this peptide could also affect other cellular processes besides causing membrane destabilization. NAPHT-BP100 showed increased antibacterial and hemolytic activities, compared to BP100, and may constitute an efficient antimicrobial agent for dermatological use. By conjugating BP100 and naphthalimide DNA binding properties, NAPHT-BP100 bound to a large extent to the bacterial membrane and could more efficiently destabilize it. We also speculate that peptide could enter the bacteria cell and interact with its DNA in the cytoplasm.

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Does membrane curvature elastic energy play a role in mediating oxidative stress in lipid membranes?

Free Radical Biology and Medicine ◽

10.1016/j.freeradbiomed.2021.05.021 ◽

2021 ◽

Author(s):

Julia Bahja ◽

Marcus K. Dymond

Keyword(s):

Oxidative Stress ◽

Elastic Energy ◽

Lipid Membranes ◽

Membrane Curvature

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Membrane curvature and the control of GTP hydrolysis in Arf1 during COPI vesicle formation

Biochemical Society Transactions ◽

10.1042/bst0330619 ◽

2005 ◽

Vol 33 (4) ◽

pp. 619-622 ◽

Cited By ~ 24

Author(s):

B. Antonny ◽

J. Bigay ◽

J.-F. Casella ◽

G. Drin ◽

B. Mesmin ◽

...

Keyword(s):

Lipid Membranes ◽

Membrane Curvature ◽

Gtp Hydrolysis ◽

Membrane Fission ◽

Transport Vesicles ◽

Highly Sensitive ◽

Copi Vesicle ◽

Membrane Budding ◽

Gtpase Cycle ◽

Adp Ribosylation Factor

The GTP switch of the small G-protein Arf1 (ADP-ribosylation factor 1) on lipid membranes promotes the polymerization of the COPI (coat protein complex I) coat, which acts as a membrane deforming shell to form transport vesicles. Real-time measurements for coat assembly on liposomes gives insights into how the GTPase cycle of Arf1 is coupled in time with the polymerization of the COPI coat and the resulting membrane deformation. One key parameter seems to be the membrane curvature. Arf-GAP1 (where GAP stands for GTPase-activating protein), which promotes GTP hydrolysis in the Arf1–COPI complex is highly sensitive to lipid packing. Its activity on Arf1-GTP increases by two orders of magnitude as the diameter of the liposomes approaches that of authentic transport vesicles (60 nm). This suggests that during membrane budding, Arf1-GTP molecules are progressively eliminated from the coated area where the membrane curvature is positive, but are protected from Arf-GAP1 at the bud neck due to the negative curvature of this region. As a result, the coat should be stable as long as the bud remains attached and should disassemble as soon as membrane fission occurs.

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