scholarly journals Vesicular Release Dynamics are Altered by Interaction between Chemical Cargo and Vesicle Membrane Lipids

2021 ◽  
Author(s):  
Farzaneh Asadpour ◽  
Xinwei Zhang ◽  
Mohammad Mazloum-Ardakani ◽  
Maysam Mirzaei ◽  
Soodabeh Majdi ◽  
...  
Keyword(s):  
Membrane Lipids ◽  
Release Time ◽  
Vesicle Membrane ◽  
Liposome Membrane ◽  
Chemical Release ◽  
Physiological Processes ◽  
Vesicular Release ◽  
Double Exponential ◽  
Desorption Rate Constant ◽  
Release Model

We used liposomes loaded with different monoamines, dopamine (DA) and serotonin (5-HT), to simulate vesicular release and to monitor the dynamics of chemical release from isolated vesicles during vesicle impact electrochemical cytometry (VIEC). The release of DA from liposomes presents a longer release time compared to 5-HT. Modelling the release time showed that DA filled vesicles had a higher percentage of events where the time for the peak fall was better fit to a double exponential (DblExp) decay function, suggesting multiple kinetic steps in the release. By fitting to a desorption-release model, where the transmitters adsorbed to the vesicle membrane, the dissociation rates of DA and 5-HT from liposome membrane were estimated. DA has a lower desorption rate constant, which leads to slower DA release than that observed for 5-HT, whereas there is little difference in pore size. The alteration of vesicular release dynamics due to the interaction between chemical cargo and vesicle membrane lipids provides an important mechanism to regulate vesicular release in chemical and physiological processes. It is highly possible that this introduces a fundamental chemical regulation difference between transmitters during exocytosis.

scholarly journals Vesicular Release Dynamics are Altered by Interaction between Chemical Cargo and Vesicle Membrane Lipids

2021 ◽  
Author(s):  
Farzaneh Asadpour ◽  
Xinwei Zhang ◽  
Mohammad Mazloum-Ardakani ◽  
Maysam Mirzaei ◽  
Soodabeh Majdi ◽  
...  
Keyword(s):  
Membrane Lipids ◽  
Release Time ◽  
Vesicle Membrane ◽  
Liposome Membrane ◽  
Chemical Release ◽  
Physiological Processes ◽  
Vesicular Release ◽  
Double Exponential ◽  
Desorption Rate Constant ◽  
Release Model

We used liposomes loaded with different monoamines, dopamine (DA) and serotonin (5-HT), to simulate vesicular release and to monitor the dynamics of chemical release from isolated vesicles during vesicle impact electrochemical cytometry (VIEC). The release of DA from liposomes presents a longer release time compared to 5-HT. Modelling the release time showed that DA filled vesicles had a higher percentage of events where the time for the peak fall was better fit to a double exponential (DblExp) decay function, suggesting multiple kinetic steps in the release. By fitting to a desorption-release model, where the transmitters adsorbed to the vesicle membrane, the dissociation rates of DA and 5-HT from liposome membrane were estimated. DA has a lower desorption rate constant, which leads to slower DA release than that observed for 5-HT, whereas there is little difference in pore size. The alteration of vesicular release dynamics due to the interaction between chemical cargo and vesicle membrane lipids provides an important mechanism to regulate vesicular release in chemical and physiological processes. It is highly possible that this introduces a fundamental chemical regulation difference between transmitters during exocytosis.

scholarly journals Vesicular Release Dynamics are Altered by Interaction between Chemical Cargo and Vesicle Membrane Lipids

2021 ◽  
Author(s):  
Farzaneh Asadpour ◽  
Xinwei Zhang ◽  
Mohammad Mazloum ◽  
Meysam Mirzaei ◽  
Soodabeh Majdib ◽  
...  
Keyword(s):  
Membrane Lipids ◽  
Vesicle Membrane ◽  
Multiple Factors ◽  
Vesicular Release

The release of cargo from soft vesicles, an essential process for chemical delivery, is mediated by multiple factors. Among them, the regulation by the interactions between the chemical cargo species...

scholarly journals Improved red blood cell preservation correlates with decreased loss of bands 3, 4.1, acetylcholinestrase, and lipids in microvesicles

Blood ◽  
1996 ◽  
Vol 87 (4) ◽  
pp. 1612-1616 ◽  
Author(s):  
UJ Dumaswala ◽  
RU Dumaswala ◽  
DS Levin ◽  
TJ Greenwalt
Keyword(s):  
Fluorescence Anisotropy ◽  
Ache Activity ◽  
Membrane Lipids ◽  
Final Concentration ◽  
Vesicle Membrane ◽  
Rbc Membrane ◽  
Additive Solution ◽  
Cell Preservation

In earlier studies we have shown that a final concentration of 0.69% glycerol in blood mixed with an experimental additive solution, EAS 25, improves the in vitro quality and in vivo survival of red blood cells (RBCs). The objective of this study was to determine if the better preservation of RBCs in EAS 25 is correlated with the improved maintenance of membrane lipids and proteins and decreased vesiculation. Split units of RBCs were stored in Adsol or EAS 25 (mmol/L: adenine 2/2, dextrose 122/110, mannitol 42/55, glycerol 0/150, NaCl 154/50). After 12 weeks storage, RBC and microvesicle membranes were analyzed for cholesterol, phospholipid, diphenyl hexatriene fluorescence anisotropy, and acetylcholinesterase (AchE) activity. Bands 3 and 4.1 were identified in the microvesicle membranes by immunoblotting. The RBC membrane cholesterol, phospholipids, and AchE remained higher in EAS 25 than in Adsol (P < .001). Vesicle membrane lipids and AchE in EAS 25 were significantly less than in Adsol (P < .001). The fluidity of stored cells in both the solutions was greater than the prestorage samples. Immunoblotting analyses showed that bands 3 and 4.1 were greatly reduced in the microvesicle membranes shed by the RBCs stored in EAS 25 compared with those formed in Adsol.

scholarly journals Plasma Membrane Lipid Domains as Platforms for Vesicle Biogenesis and Shedding?

Biomolecules ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 94 ◽  
Author(s):  
Hélène Pollet ◽  
Louise Conrard ◽  
Anne-Sophie Cloos ◽  
Donatienne Tyteca
Keyword(s):  
Plasma Membrane ◽  
Membrane Lipids ◽  
Disease Diagnosis ◽  
Membrane Lipid ◽  
Lipid Domains ◽  
Disease Evolution ◽  
Physiological Processes ◽  
Plasma Membrane Lipid ◽  
Vesicle Biogenesis ◽  
Few Data

Extracellular vesicles (EVs) contribute to several pathophysiological processes and appear as emerging targets for disease diagnosis and therapy. However, successful translation from bench to bedside requires deeper understanding of EVs, in particular their diversity, composition, biogenesis and shedding mechanisms. In this review, we focus on plasma membrane-derived microvesicles (MVs), far less appreciated than exosomes. We integrate documented mechanisms involved in MV biogenesis and shedding, focusing on the red blood cell as a model. We then provide a perspective for the relevance of plasma membrane lipid composition and biophysical properties in microvesiculation on red blood cells but also platelets, immune and nervous cells as well as tumor cells. Although only a few data are available in this respect, most of them appear to converge to the idea that modulation of plasma membrane lipid content, transversal asymmetry and lateral heterogeneity in lipid domains may play a significant role in the vesiculation process. We suggest that lipid domains may represent platforms for inclusion/exclusion of membrane lipids and proteins into MVs and that MVs could originate from distinct domains during physiological processes and disease evolution.

scholarly journals Local protein dynamics during microvesicle exocytosis in neuroendocrine cells

2018 ◽  
Vol 29 (15) ◽  
pp. 1891-1903 ◽  
Author(s):  
Agila Somasundaram ◽  
Justin W. Taraska
Keyword(s):  
Protein Dynamics ◽  
Spatial Dynamics ◽  
Neuroendocrine Cells ◽  
Live Cells ◽  
Rab Proteins ◽  
Vesicle Membrane ◽  
Physiological Processes ◽  
Associated Proteins ◽  
Membrane Bound ◽  
Local Protein

Calcium-triggered exocytosis is key to many physiological processes, including neurotransmitter and hormone release by neurons and endocrine cells. Dozens of proteins regulate exocytosis, yet the temporal and spatial dynamics of these factors during vesicle fusion remain unclear. Here we use total internal reflection fluorescence microscopy to visualize local protein dynamics at single sites of exocytosis of small synaptic-like microvesicles in live cultured neuroendocrine PC12 cells. We employ two-color imaging to simultaneously observe membrane fusion (using vesicular acetylcholine ACh transporter tagged to pHluorin) and the dynamics of associated proteins at the moments surrounding exocytosis. Our experiments show that many proteins, including the SNAREs syntaxin1 and VAMP2, the SNARE modulator tomosyn, and Rab proteins, are preclustered at fusion sites and rapidly lost at fusion. The ATPase N-ethylmaleimide–sensitive factor is locally recruited at fusion. Interestingly, the endocytic Bin-Amphiphysin-Rvs domain–containing proteins amphiphysin1, syndapin2, and endophilins are dynamically recruited to fusion sites and slow the loss of vesicle membrane-bound cargo from fusion sites. A similar effect on vesicle membrane protein dynamics was seen with the overexpression of the GTPases dynamin1 and dynamin2. These results suggest that proteins involved in classical clathrin-mediated endocytosis can regulate exocytosis of synaptic-like microvesicles. Our findings provide insights into the dynamics, assembly, and mechanistic roles of many key factors of exocytosis and endocytosis at single sites of microvesicle fusion in live cells.

scholarly journals Polydiacetylene Vesicles Acting as Colorimetric Sensor for the Detection of Plantaricin LD1 Purified From Lactobacillus Plantarum LD1

2021 ◽  
Author(s):  
Manoj Kumar Yadav ◽  
Santosh Kumar Tiwari
Keyword(s):  
Antimicrobial Peptides ◽  
Lactobacillus Plantarum ◽  
Pore Formation ◽  
Membrane Lipids ◽  
Membrane Disruption ◽  
Target Cells ◽  
Artificial Membrane ◽  
Physiological Processes ◽  
Colorimetric Response ◽  
Pda Vesicles

Abstract The interaction of antimicrobial peptides with membrane lipids plays a major role in numerous physiological processes. Bacteriocins are antimicrobial peptides known to kill target cells by pore formation and membrane disruption. In this study, polydiacetylene (PDA) vesicles were applied as artificial membrane for detection of plantaricin LD1 purified from Lactobacillus plantarum LD1. Plantaricin LD1 (200 µg/ml) was able to change the color of PDA vesicles from blue to red with colorimetric response CR % 30.26 ± 0.59. Nisin (200 µg/ml), used as control, also changed the color of the vesicles with CR % 50.56 ± 0.98 validating the membrane-acting nature of these bacteriocins. The PDA vesicles treated with nisin and plantaricin LD1 showed increased infrared absorbance at 1411.46 cm-1 and 1000-1150 cm-1 indicated the interaction of bacteriocins with phospholipids and fatty acids, respectively. Further, microscopic examination also suggested the disruption of bacteriocin-treated vesicles indicating the interaction of bacteriocins. These findings suggest that the PDA vesicles may be used as bio-mimetic sensor for the detection of bacteriocins produced by several probiotics in food and therapeutic applications.

scholarly journals Current knowledge and recent advances in understanding metabolism of the model cyanobacterium Synechocystis sp. PCC 6803

2020 ◽  
Vol 40 (4) ◽  
Author(s):  
Lauren A. Mills ◽  
Alistair J. McCormick ◽  
David J. Lea-Smith
Keyword(s):  
Amino Acids ◽  
Heterotrophic Bacteria ◽  
Membrane Lipids ◽  
Current Knowledge ◽  
Oxygenic Photosynthesis ◽  
Photosynthetic Organisms ◽  
Physiological Processes ◽  
Synechocystis Sp ◽  
Pcc 6803

Abstract Cyanobacteria are key organisms in the global ecosystem, useful models for studying metabolic and physiological processes conserved in photosynthetic organisms, and potential renewable platforms for production of chemicals. Characterizing cyanobacterial metabolism and physiology is key to understanding their role in the environment and unlocking their potential for biotechnology applications. Many aspects of cyanobacterial biology differ from heterotrophic bacteria. For example, most cyanobacteria incorporate a series of internal thylakoid membranes where both oxygenic photosynthesis and respiration occur, while CO2 fixation takes place in specialized compartments termed carboxysomes. In this review, we provide a comprehensive summary of our knowledge on cyanobacterial physiology and the pathways in Synechocystis sp. PCC 6803 (Synechocystis) involved in biosynthesis of sugar-based metabolites, amino acids, nucleotides, lipids, cofactors, vitamins, isoprenoids, pigments and cell wall components, in addition to the proteins involved in metabolite transport. While some pathways are conserved between model cyanobacteria, such as Synechocystis, and model heterotrophic bacteria like Escherichia coli, many enzymes and/or pathways involved in the biosynthesis of key metabolites in cyanobacteria have not been completely characterized. These include pathways required for biosynthesis of chorismate and membrane lipids, nucleotides, several amino acids, vitamins and cofactors, and isoprenoids such as plastoquinone, carotenoids, and tocopherols. Moreover, our understanding of photorespiration, lipopolysaccharide assembly and transport, and degradation of lipids, sucrose, most vitamins and amino acids, and haem, is incomplete. We discuss tools that may aid our understanding of cyanobacterial metabolism, notably CyanoSource, a barcoded library of targeted Synechocystis mutants, which will significantly accelerate characterization of individual proteins.

scholarly journals Interactions of the Lysosomotropic Detergent O-Methyl-Serine Dodecylamide Hydrochloride (MSDH) with Lipid Bilayer Membranes—Implications for Cell Toxicity

2020 ◽  
Vol 21 (9) ◽  
pp. 3136 ◽  
Author(s):  
Ana-Maria Villamil Giraldo ◽  
Ida Eriksson ◽  
Stefan Wennmalm ◽  
Timmy Fyrner ◽  
Thomas Ederth ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Lipids ◽  
Apoptotic Cell ◽  
Human Fibroblasts ◽  
Membrane Integrity ◽  
Chemical Properties ◽  
High Ratio ◽  
Lipid Bilayer Membranes ◽  
High Concentration ◽  
Liposome Membrane

O-methyl-serine dodecylamine hydrochloride (MSDH) is a detergent that accumulates selectively in lysosomes, a so-called lysosomotropic detergent, with unexpected chemical properties. At physiological pH, it spontaneously forms vesicles, which disassemble into small aggregates (probably micelles) below pH 6.4. In this study, we characterize the interaction between MSDH and liposomes at different pH and correlate the findings to toxicity in human fibroblasts. We find that the effect of MSDH on lipid membranes is highly pH-dependent. At neutral pH, the partitioning of MSDH into the liposome membrane is immediate and causes the leakage of small fluorophores, unless the ratio between MSDH and lipids is kept low. At pH 5, the partitioning of MSDH into the membrane is kinetically impeded since MSDH is charged and a high ratio between MSDH and the lipids is required to permeabilize the membrane. When transferred to cell culture conditions, the ratio between MSDH and plasma membrane lipids must therefore be low, at physiological pH, to maintain plasma membrane integrity. Transmission electron microscopy suggests that MSDH vesicles are taken up by endocytosis. As the pH of the endosomal compartment progressively drops, MSDH vesicles disassemble, leading to a high concentration of increasingly charged MSDH in small aggregates inside the lysosomes. At sufficiently high MSDH concentrations, the lysosome is permeabilized, the proteolytic content released to the cytosol and apoptotic cell death is induced.

scholarly journals Redistribution of cholesterol from vesicle to plasmalemma controls fusion pore geometry

2020 ◽  
Author(s):  
Boštjan Rituper ◽  
Alenka Guček ◽  
Marjeta Lisjak ◽  
Urszula Gorska ◽  
Aleksandra Šakanović ◽  
...  
Keyword(s):  
Pore Diameter ◽  
Membrane Lipids ◽  
Radial Force ◽  
Fusion Pore ◽  
Pore Geometry ◽  
Cholesterol Depletion ◽  
List Type ◽  
Vesicle Membrane ◽  
Membrane Pore ◽  
Outer Leaflet

ABSTRACTEukaryotic vesicles fuse with the plasmalemma to form the fusion pore, previously considered to be unstable with widening of the pore diameter. Recent studies established that the pore diameter is stable, reflecting balanced forces of widening and closure. Proteins are considered key regulators of the fusion pore, whereas the role of membrane lipids remains unclear. Super-resolution microscopy revealed that lactotroph secretory vesicles discharge cholesterol after stimulation of exocytosis; subsequently, vesicle cholesterol redistributes to the outer leaflet of the plasmalemma. Cholesterol depletion in lactotrophs and astrocytes evokes release of vesicle hormone, indicating that cholesterol constricts the fusion pore. A new model of cholesterol-dependent fusion pore diameter regulation is proposed. High-resolution measurements of fusion pore conductance confirmed that the fusion pore widens with cholesterol depletion and constricts with cholesterol enrichment. In fibroblasts lacking the Npc1 protein, in which cholesterol accumulates in vesicles, the fusion pore is narrower than in controls, showing that cholesterol regulates fusion pore geometry.Graphical AbstractTop: stages through which a vesicle interacts with the plasmalemma. Stage A denotes hemifusion, which proceeds to stage B, with a narrow fusion pore, which can then reversibly open (stage C), before widening fully (stage D). Bottom: redistribution of cholesterol from the vesicle to the outer leaflet of the plasmalemma controls fusion pore constriction.In BriefA membrane pore is formed when the vesicle membrane fuses with the plasmalemma. Proteins were considered key regulators of the opening and closing of this fusion pore. Here, evidence is provided to show that cholesterol, a membrane constituent, determines a radial force constricting the fusion pore, revealing that the fusion pore functions as a proteolipidic structure.HighlightsIntravesicular cholesterol redistributes to the outer leaflet of the plasmalemma.Cholesterol depletion widens the fusion pore, whereas cholesterol enrichment constricts the fusion pore.A model of cholesterol-dependent force preventing fusion pore widening is developed.Disease-related increase in vesicle cholesterol constricts the fusion pore.

scholarly journals Local Protein Dynamics during Microvesicle Exocytosis in Neuroendocrine Cells

2018 ◽  
Author(s):  
Agila Somasundaram ◽  
Justin Taraska
Keyword(s):  
Protein Dynamics ◽  
Spatial Dynamics ◽  
Neuroendocrine Cells ◽  
Live Cells ◽  
Rab Proteins ◽  
Vesicle Membrane ◽  
Bar Domain ◽  
Physiological Processes ◽  
Associated Proteins ◽  
Local Protein

ABSTRACTCalcium triggered exocytosis is key to many physiological processes, including neurotransmitter and hormone release by neurons and endocrine cells. Dozens of proteins regulate exocytosis, yet the temporal and spatial dynamics of these factors during vesicle fusion remain unclear. Here we use total internal reflection fluorescence microscopy to visualize local protein dynamics at single sites of exocytosis of small synaptic-like microvesicles in live cultured neuroendocrine PC12 cells. We employ two-color imaging to simultaneously observe membrane fusion (using vesicular acetylcholine transporter (VAChT) tagged to pHluorin) and the dynamics of associated proteins at the moments surrounding exocytosis. Our experiments show that many proteins, including the SNAREs syntaxin1 and VAMP2, the SNARE modulator tomosyn, and Rab proteins, are pre-clustered at fusion sites and rapidly lost at fusion. The ATPase NSF is locally recruited at fusion. Interestingly, the endocytic BAR domain-containing proteins amphiphysin1, syndapin2, and endophilins are dynamically recruited to fusion sites, and slow the loss of vesicle membrane-bound cargo from fusion sites. A similar effect on vesicle membrane protein dynamics was seen with the over-expression of the GTPases dynamin1 and dynamin2. These results suggest that proteins involved in classical clathrin-mediated endocytosis can regulate exocytosis of synaptic-like microvesicles. Our findings provide insights into the dynamics, assembly, and mechanistic roles of many key factors of exocytosis and endocytosis at single sites of microvesicle fusion in live cells.

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