scholarly journals Single-vesicle imaging reveals lipid-selective and stepwise membrane disruption by monomeric α-synuclein

2020 ◽  
pp. 201914670 ◽  
Author(s):  
Jonas K. Hannestad ◽  
Sandra Rocha ◽  
Björn Agnarsson ◽  
Vladimir P. Zhdanov ◽  
Pernilla Wittung-Stafshede ◽  
...  
Keyword(s):  
Protein Function ◽  
Lipid Membranes ◽  
Structural Changes ◽  
Lipid Vesicles ◽  
Membrane Disruption ◽  
Label Free ◽  
Asymmetric Membrane ◽  
Neuronal Protein ◽  
Interaction Kinetics ◽  
Single Vesicle

The interaction of the neuronal protein α-synuclein with lipid membranes appears crucial in the context of Parkinson’s disease, but the underlying mechanistic details, including the roles of different lipids in pathogenic protein aggregation and membrane disruption, remain elusive. Here, we used single-vesicle resolution fluorescence and label-free scattering microscopy to investigate the interaction kinetics of monomeric α-synuclein with surface-tethered vesicles composed of different negatively charged lipids. Supported by a theoretical model to account for structural changes in scattering properties of surface-tethered lipid vesicles, the data demonstrate stepwise vesicle disruption and asymmetric membrane deformation upon α-synuclein binding to phosphatidylglycerol vesicles at protein concentrations down to 10 nM (∼100 proteins per vesicle). In contrast, phosphatidylserine vesicles were only marginally affected. These insights into structural consequences of α-synuclein interaction with lipid vesicles highlight the contrasting roles of different anionic lipids, which may be of mechanistic relevance for both normal protein function (e.g., synaptic vesicle binding) and dysfunction (e.g., mitochondrial membrane interaction).

scholarly journals Responsive core-shell DNA particles trigger lipid-membrane disruption and bacteria entrapment

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michal Walczak ◽  
Ryan A. Brady ◽  
Leonardo Mancini ◽  
Claudia Contini ◽  
Roger Rubio-Sánchez ◽  
...  
Keyword(s):  
Immune Cells ◽  
Lipid Membranes ◽  
Lipid Membrane ◽  
Lipid Vesicles ◽  
Membrane Disruption ◽  
Dna Nanostructures ◽  
E Coli ◽  
Synthetic Dna ◽  
Amyloid Aggregates ◽  
Particle Coalescence

AbstractBiology has evolved a variety of agents capable of permeabilizing and disrupting lipid membranes, from amyloid aggregates, to antimicrobial peptides, to venom compounds. While often associated with disease or toxicity, these agents are also central to many biosensing and therapeutic technologies. Here, we introduce a class of synthetic, DNA-based particles capable of disrupting lipid membranes. The particles have finely programmable size, and self-assemble from all-DNA and cholesterol-DNA nanostructures, the latter forming a membrane-adhesive core and the former a protective hydrophilic corona. We show that the corona can be selectively displaced with a molecular cue, exposing the ‘sticky’ core. Unprotected particles adhere to synthetic lipid vesicles, which in turn enhances membrane permeability and leads to vesicle collapse. Furthermore, particle-particle coalescence leads to the formation of gel-like DNA aggregates that envelop surviving vesicles. This response is reminiscent of pathogen immobilisation through immune cells secretion of DNA networks, as we demonstrate by trapping E. coli bacteria.

scholarly journals Histo-blood group antigens of glycosphingolipids predict susceptibility of human intestinal enteroids to norovirus infection

2020 ◽  
Vol 295 (47) ◽  
pp. 15974-15987 ◽  
Author(s):  
Inga Rimkute ◽  
Konrad Thorsteinsson ◽  
Marcus Henricsson ◽  
Victoria R. Tenge ◽  
Xiaoming Yu ◽  
...  
Keyword(s):  
Blood Group ◽  
Lipid Membranes ◽  
Molecular Mechanisms ◽  
Ex Vivo ◽  
Particle Interaction ◽  
Lipid Vesicles ◽  
Blood Group Antigens ◽  
Interaction Kinetics ◽  
Glycerolipid Composition ◽  
The Individual

The molecular mechanisms behind infection and propagation of human restricted pathogens such as human norovirus (HuNoV) have defied interrogation because they were previously unculturable. However, human intestinal enteroids (HIEs) have emerged to offer unique ex vivo models for targeted studies of intestinal biology, including inflammatory and infectious diseases. Carbohydrate-dependent histo-blood group antigens (HBGAs) are known to be critical for clinical infection. To explore whether HBGAs of glycosphingolipids contribute to HuNoV infection, we obtained HIE cultures established from stem cells isolated from jejunal biopsies of six individuals with different ABO, Lewis, and secretor genotypes. We analyzed their glycerolipid and sphingolipid compositions and quantified interaction kinetics and the affinity of HuNoV virus-like particles (VLPs) to lipid vesicles produced from the individual HIE-lipid extracts. All HIEs had a similar lipid and glycerolipid composition. Sphingolipids included HBGA-related type 1 chain glycosphingolipids (GSLs), with HBGA epitopes corresponding to the geno- and phenotypes of the different HIEs. As revealed by single-particle interaction studies of Sydney GII.4 VLPs with glycosphingolipid-containing HIE membranes, both binding kinetics and affinities explain the patterns of susceptibility toward GII.4 infection for individual HIEs. This is the first time norovirus VLPs have been shown to interact specifically with secretor gene–dependent GSLs embedded in lipid membranes of HIEs that propagate GII.4 HuNoV ex vivo, highlighting the potential of HIEs for advanced future studies of intestinal glycobiology and host-pathogen interactions.

Free-Standing Lipid Bilayers Based on Nanopore Array and Ion Channel Formation

2019 ◽  
Vol 19 (11) ◽  
pp. 7149-7155
Author(s):  
Shengwei Tan ◽  
Ling Zhang ◽  
Lijuan Yu ◽  
Lei Xu
Keyword(s):  
Silicon Nitride ◽  
Ion Channel ◽  
Lipid Bilayers ◽  
Single Molecule ◽  
Protein Function ◽  
Lipid Membranes ◽  
Membrane Resistance ◽  
Label Free ◽  
Free Standing ◽  
Membrane Lifetime

Integrated nanopores are novel and versatile single-molecule sensors for individual label-free biopolymer detection and characterization. However, their studies and application requires a stable lipid bilayer to maintain protein function. Herein, we describe a method for producing lipid bilayers across a nanopore array on a silicon nitride substrate. We used a painting technique commonly used with Teflon films to embed α-hemolysin (α-HL) into bilayer lipid membranes (BLMs) to form an ion channel. This was carried out in nanofluid developed in our lab. The membrane formation process, stability of BLMs and ion channel recordings were monitored by patch clamp in real-time. BLM formation was demonstrated by electrical recording (<10 pS conductance) of suspended lipid bilayers spanning a nanopore in the range of ±100 mV. Membrane resistance (Rm) and capacitance (Cm) of the device with the bilayer were assessed by membrane test as above 1.0 GΩ and ~20±2 pF, respectively. The silicon nitride surface and aperture edge were smooth at the nanometer lever leading to remarkable membrane stability. The membrane lifetime was 5–24 h. A single α-HL channel inserted in 30–60 min applied a potential of +100 mV. The α-HL channel currents were recorded at ~100±10 pA. Such integrated nanopores enable analysis of channel functions under various solution conditions from the same BLM. This will open up a variety of applications for ion channels including high-throughput medical screening and diagnosis.

scholarly journals Formation of Giant Lipid Vesicles in the Presence of Nonelectrolytes—Glucose, Sucrose, Sorbitol and Ethanol

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 945
Author(s):  
Qiong Wang ◽  
Ning Hu ◽  
Jincan Lei ◽  
Qiurong Qing ◽  
Jing Huang ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Cell Membrane ◽  
Lipid Membranes ◽  
Volume Fraction ◽  
Hydrodynamic Force ◽  
Lipid Vesicles ◽  
Ethanol Solution ◽  
Sugar Solution ◽  
Ethanol Content ◽  
Membrane Models

Lipid vesicles, especially giant lipid vesicles (GLVs), are usually adopted as cell membrane models and their preparation has been widely studied. However, the effects of some nonelectrolytes on GLV formation have not been specifically studied so far. In this paper, the effects of the nonelectrolytes, including sucrose, glucose, sorbitol and ethanol, and their coexistence with sodium chloride, on the lipid hydration and GLV formation were investigated. With the hydration method, it was found that the sucrose, glucose and sorbitol showed almost the same effect. Their presence in the medium enhanced the hydrodynamic force on the lipid membranes, promoting the GLV formation. GLV formation was also promoted by the presence of ethanol with ethanol volume fraction in the range of 0 to 20 percent, but higher ethanol content resulted in failure of GLV formation. However, the participation of sodium chloride in sugar solution and ethanol solution stabilized the lipid membranes, suppressing the GLV formation. In addition, the ethanol and the sodium chloride showed the completely opposite effects on lipid hydration. These results could provide some suggestions for the efficient preparation of GLVs.

scholarly journals Tethered Lipid Membranes as a Nanoscale Arrangement Towards Non-Invasive Analysis of Acute Pancreatitis

Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 755
Author(s):  
Rima Budvytyte ◽  
Akvile Milasiute ◽  
Dalius Vitkus ◽  
Kestutis Strupas ◽  
Aiste Gulla ◽  
...  
Keyword(s):  
Acute Pancreatitis ◽  
Lipid Membranes ◽  
Electrochemical Impedance ◽  
Membrane Integrity ◽  
Electrochemical Technique ◽  
Label Free ◽  
Non Invasive ◽  
Novel Approach ◽  
Analytical System ◽  
Shock Proteins

Extracellular heat shock proteins (HSPs) mediate immunological functions and are involved in pathologies such as infection, stress, and cancer. Here, we demonstrated the dependence of an amount of HSP70 and HSP90 in serum vs. severity of acute pancreatitis (AP) on a cohort of 49 patients. Tethered bilayer lipid membranes (tBLMs) have been developed to investigate HSPs’ interactions with tBLMs that can be probed by electrochemical impedance spectroscopy (EIS). The results revealed that HSP70 and HSP90 interact via different mechanisms. HSP70 shows the damage of the membrane, while HSP90 increases the insulation properties of tBLM. These findings provide evidence that EIS offers a novel approach for the study of the changes in membrane integrity induced by HSPs proteins. Herein, we present an alternative electrochemical technique, without any immunoprobes, that allows for the monitoring of HSPs on nanoscaled tBLM arrangement in biologics samples such us human urine. This study demonstrates the great potential of tBLM to be used as a membrane based biosensor for novel, simple, and non-invasive label-free analytical system for the prediction of AP severity.

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

Nano Letters ◽  
2012 ◽  
Vol 12 (11) ◽  
pp. 5719-5725 ◽  
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

scholarly journals The Structural Integrity of the Model Lipid Membrane during Induced Lipid Peroxidation: The Role of Flavonols in the Inhibition of Lipid Peroxidation

Antioxidants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 430 ◽  
Author(s):  
Anja Sadžak ◽  
Janez Mravljak ◽  
Nadica Maltar-Strmečki ◽  
Zoran Arsov ◽  
Goran Baranović ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Structural Changes ◽  
Structural Integrity ◽  
Lipid Membrane ◽  
Membrane Properties ◽  
Structural Reorganization ◽  
Unsaturated Lipids ◽  
Oxidative Attack

The structural integrity, elasticity, and fluidity of lipid membranes are critical for cellular activities such as communication between cells, exocytosis, and endocytosis. Unsaturated lipids, the main components of biological membranes, are particularly susceptible to the oxidative attack of reactive oxygen species. The peroxidation of unsaturated lipids, in our case 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), induces the structural reorganization of the membrane. We have employed a multi-technique approach to analyze typical properties of lipid bilayers, i.e., roughness, thickness, elasticity, and fluidity. We compared the alteration of the membrane properties upon initiated lipid peroxidation and examined the ability of flavonols, namely quercetin (QUE), myricetin (MCE), and myricitrin (MCI) at different molar fractions, to inhibit this change. Using Mass Spectrometry (MS) and Fourier Transform Infrared Spectroscopy (FTIR), we identified various carbonyl products and examined the extent of the reaction. From Atomic Force Microscopy (AFM), Force Spectroscopy (FS), Small Angle X-Ray Scattering (SAXS), and Electron Paramagnetic Resonance (EPR) experiments, we concluded that the membranes with inserted flavonols exhibit resistance against the structural changes induced by the oxidative attack, which is a finding with multiple biological implications. Our approach reveals the interplay between the flavonol molecular structure and the crucial membrane properties under oxidative attack and provides insight into the pathophysiology of cellular oxidative injury.

scholarly journals The interplay between lipids and dopamine on α-synuclein oligomerization and membrane binding

2013 ◽  
Vol 33 (5) ◽  
Author(s):  
Chi L. L. Pham ◽  
Roberto Cappai
Keyword(s):  
Lipid Membranes ◽  
Amyloid Fibrils ◽  
Lipid Membrane ◽  
Hydrophobic Interactions ◽  
Membrane Integrity ◽  
Lipid Vesicles ◽  
Helical Conformation ◽  
Unfolded Protein ◽  
Natively Unfolded Protein ◽  
Natively Unfolded

The deposition of α-syn (α-synuclein) as amyloid fibrils and the selective loss of DA (dopamine) containing neurons in the substantia nigra are two key features of PD (Parkinson's disease). α-syn is a natively unfolded protein and adopts an α-helical conformation upon binding to lipid membrane. Oligomeric species of α-syn have been proposed to be the pathogenic species associated with PD because they can bind lipid membranes and disrupt membrane integrity. DA is readily oxidized to generate reactive intermediates and ROS (reactive oxygen species) and in the presence of DA, α-syn form of SDS-resistant soluble oligomers. It is postulated that the formation of the α-syn:DA oligomers involves the cross-linking of DA-melanin with α-syn, via covalent linkage, hydrogen and hydrophobic interactions. We investigate the effect of lipids on DA-induced α-syn oligomerization and studied the ability of α-syn:DA oligomers to interact with lipids vesicles. Our results show that the interaction of α-syn with lipids inhibits the formation of DA-induced α-syn oligomers. Moreover, the α-syn:DA oligomer cannot interact with lipid vesicles or cause membrane permeability. Thus, the formation of α-syn:DA oligomers may alter the actions of α-syn which require membrane association, leading to disruption of its normal cellular function.

scholarly journals Label-free imaging of age-related cardiac structural changes in non-human primates using multiphoton nonlinear microscopy

2021 ◽  
Author(s):  
Amara Khan ◽  
Fernanda Ramos-Gomes ◽  
Andrea Markus ◽  
Matthias Mietsch ◽  
Rabea Hinkel ◽  
...  
Keyword(s):  
Structural Changes ◽  
Nonlinear Microscopy ◽  
Label Free ◽  
Age Related
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