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Frontiers in Molecular Neuroscience 2022Interactions of lipid vesicles play important roles in a large variety of functions and dysfunctions in the human body. Vital for several biochemical functions is the...
Interactions of lipid vesicles play important roles in a large variety of functions and dysfunctions in the human body. Vital for several biochemical functions is the interaction between monomeric proteins and lipid membranes, and the induced phenomena such as fusion between vesicles and cell membranes, lipid exchange between the membranes, or vesicle fission. Identification of single events and their frequency of occurrence would provide valuable information about protein-lipid interactions in both healthy and degenerative pathways. In this work, we present a single-vesicle intensity and colocalization fluorescence microscopy assay with a custom-written MATLAB analysis program. The assay can be used to study lipid exchange as well as vesicle fusion and fission between two vesicle populations labeled with different fluorescent dyes. Vesicles from the two populations are first mixed and docked to a glass surface. The sample is then simultaneously imaged using two separate wavelength channels monitoring intensity changes and colocalization of vesicles from the two populations. The monomeric pre-synaptic protein α-synuclein (α-syn) and small unilamellar vesicles consisting of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dioleoyl-sn-glycero-3-phospho-L-serine, (DOPS), and monosialotetrahexosylganglioside (GM1) were used as a model system to evaluate the method. From our analysis, neither α-syn induced fusion nor lipid exchange was observed for vesicles consisting of DOPC:DOPS (7:3). However, including 10% GM1 in the vesicles resulted in a 91% increase of the number of vesicles within 10 min, combined with a 57% decrease in the average fluorescence intensity per vesicle, indicating that approximately half of the vesicles underwent fission. The method facilitates the study of lipid vesicle fusion, fission, and lipid exchange under controlled conditions. It also allows these events to be studied for systems with more complex composition including exosomes and lipid-based drug carriers, to enable a better understanding of their physicochemical properties.
PubMed: 36533132
DOI: 10.3389/fnmol.2022.1007699 -
Applied and Environmental Microbiology Oct 2019Large surface-to-volume ratios provide optimal nutrient uptake conditions for small microorganisms in oligotrophic habitats. The surface area can be increased with...
Large surface-to-volume ratios provide optimal nutrient uptake conditions for small microorganisms in oligotrophic habitats. The surface area can be increased with appendages. Here, we describe chains of interconnecting vesicles protruding from cells of strain Hel3_A1_48, affiliating with spp. within the and originating from coastal free-living bacterioplankton. The chains were up to 10 μm long and had vesicles emanating from the outer membrane with a single membrane and a size of 80 to 100 nm by 50 to 80 nm. Cells extruded membrane tubes in the exponential phase, whereas vesicle chains dominated on cells in the stationary growth phase. This formation is known as pearling, a physical morphogenic process in which membrane tubes protrude from liposomes and transform into chains of interconnected vesicles. Proteomes of whole-cell membranes and of detached vesicles were dominated by outer membrane proteins, including the type IX secretion system and surface-attached peptidases, glycoside hydrolases, and endonucleases. Fluorescein-labeled laminarin stained the cells and the vesicle chains. Thus, the appendages provide binding domains and degradative enzymes on their surfaces and probably storage volume in the vesicle lumen. Both may contribute to the high abundance of these -affiliated bacteria during laminarin utilization shortly after spring algal blooms. Microorganisms produce membrane vesicles. One synthesis pathway seems to be pearling that describes the physical formation of vesicle chains from phospholipid vesicles via extended tubes. Bacteria with vesicle chains had been observed as well as bacteria with tubes, but pearling was so far not observed. Here, we report the observation of, initially, tubes and then vesicle chains during the growth of a flavobacterium, suggesting biopearling of vesicle chains. The flavobacterium is abundant during spring bacterioplankton blooms developing after algal blooms and has a special set of enzymes for laminarin, the major storage polysaccharide of microalgae. We demonstrated with fluorescently labeled laminarin that the vesicle chains bind laminarin or contain laminarin-derived compounds. Proteomic analyses revealed surface-attached degradative enzymes on the outer membrane vesicles. We conclude that the large surface area and the lumen of vesicle chains may contribute to the ecological success of this marine bacterium.
Topics: Aquatic Organisms; Bacterial Outer Membrane Proteins; Cell Membrane; Eutrophication; Extracellular Vesicles; Flavobacterium; Glucans; Liposomes; Microscopy, Electron; Proteomics
PubMed: 31324630
DOI: 10.1128/AEM.00829-19 -
Scientific Reports Mar 2017Neurotransmitters and peptide hormones are secreted into outside the cell by a vesicle fusion process. Although non-coding RNA (ncRNA) that include microRNA (miRNA)...
Neurotransmitters and peptide hormones are secreted into outside the cell by a vesicle fusion process. Although non-coding RNA (ncRNA) that include microRNA (miRNA) regulates gene expression inside the cell where they are transcribed, extracellular miRNA has been recently discovered outside the cells, proposing that miRNA might be released to participate in cell-to-cell communication. Despite its importance of extracellular miRNA, the molecular mechanisms by which miRNA can be stored in vesicles and released by vesicle fusion remain enigmatic. Using next-generation sequencing, vesicle purification techniques, and synthetic neurotransmission, we observe that large dense-core vesicles (LDCVs) contain a variety of miRNAs including miR-375. Furthermore, miRNA exocytosis is mediated by the SNARE complex and accelerated by Ca. Our results suggest that miRNA can be a novel neuromodulator that can be stored in vesicles and released by vesicle fusion together with classical neurotransmitters.
Topics: Animals; Cattle; Exocytosis; Membrane Fusion; Mice; MicroRNAs; Models, Biological; PC12 Cells; Rats; Secretory Vesicles; Sequence Analysis, RNA; Vesicle-Associated Membrane Protein 2
PubMed: 28358390
DOI: 10.1038/srep45661 -
Chemical Communications (Cambridge,... Sep 2014This article deals with artificial vesicles and their membranes as reaction promoters and regulators. Among the various molecular assemblies which can form in an aqueous... (Review)
Review
This article deals with artificial vesicles and their membranes as reaction promoters and regulators. Among the various molecular assemblies which can form in an aqueous medium from amphiphilic molecules, vesicle systems are unique. Vesicles compartmentalize the aqueous solution in which they exist, independent on whether the vesicles are biological vesicles (existing in living systems) or whether they are artificial vesicles (formed in vitro from natural or synthetic amphiphiles). After the formation of artificial vesicles, their aqueous interior (the endovesicular volume) may become - or may be made - chemically different from the external medium (the exovesicular solution), depending on how the vesicles are prepared. The existence of differences between endo- and exovesicular composition is one of the features on the basis of which biological vesicles contribute to the complex functioning of living organisms. Furthermore, artificial vesicles can be formed from mixtures of amphiphiles in such a way that the vesicle membranes become molecularly, compositionally and organizationally highly complex, similarly to the lipidic matrix of biological membranes. All the various properties of artificial vesicles as membranous compartment systems emerge from molecular assembly as these properties are not present in the individual molecules the system is composed of. One particular emergent property of vesicle membranes is their possible functioning as promoters and regulators of chemical reactions caused by the localization of reaction components, and possibly catalysts, within or on the surface of the membranes. This specific feature is reviewed and highlighted with a few selected examples which range from the promotion of decarboxylation reactions, the selective binding of DNA or RNA to suitable vesicle membranes, and the reactivation of fragmented enzymes to the regulation of the enzymatic synthesis of polymers. Such type of emergent properties of vesicle membranes may have been important for the prebiological evolution of protocells, the hypothetical compartment systems preceding the first cells in those chemical and physico-chemical processes that led to the origin of life.
Topics: Animals; Humans; Membranes, Artificial; Surface-Active Agents; Transport Vesicles
PubMed: 24921467
DOI: 10.1039/c4cc02812k -
RSC Advances Sep 2019Lipid distribution in intracellular vesicles is different from that in the plasma membrane of eukaryotic cells. The lipid components in the intracellular vesicles are...
Lipid distribution in intracellular vesicles is different from that in the plasma membrane of eukaryotic cells. The lipid components in the intracellular vesicles are composed of phosphatidylserine and phosphatidylethanolamine in the outer leaflet and phosphatidylcholine and sphingomyelin in the inner leaflet. The lipid asymmetricities both in the intracellular vesicle membrane and the plasma membrane contribute to synaptic transmission functions. In this study, we developed a cell-sized asymmetric lipid vesicle system containing small-sized asymmetric lipid vesicles (of diameter 200-1000 nm) (asymmetric vesicles-in-a-vesicle), emulating lipid components in the plasma membrane and intracellular vesicle membrane of eukaryotic cells, using microfluidic technology. We successfully constructed an artificial exocytosis system using the asymmetric vesicles-in-a-vesicle system. This asymmetric vesicles-in-a-vesicle system will be helpful in understanding the mechanisms of vesicle transport, such as neurotransmission and exocytosis.
PubMed: 35530244
DOI: 10.1039/c9ra04622d -
The Journal of Neuroscience : the... Sep 2020Synaptic ribbons are thought to provide vesicles for continuous release in some retinal nonspiking neurons, yet recent studies indicate that genetic removal of the...
Synaptic ribbons are thought to provide vesicles for continuous release in some retinal nonspiking neurons, yet recent studies indicate that genetic removal of the ribbon has little effect on release kinetics. To investigate vesicle replenishment at synaptic ribbons, we used total internal reflection fluorescence microscopy to image synaptic vesicles and ribbons in retinal bipolar cells of goldfish () of both sexes. Analysis of vesicles released by trains of 30 ms depolarizations revealed that most releasable vesicles reside within 300 nm of the ribbon center. A single 30 ms step to 0 mV was sufficient to deplete the membrane-proximal vesicle pool, while triggering rapid stepwise movements of distal vesicles along the ribbon and toward the plasma membrane. Replenishment only becomes rate-limiting for recovery from paired-pulse depression for interstimulus intervals shorter than 250 ms. For longer interstimulus intervals, vesicle movement down the ribbon is fast enough to replenish released vesicles, but newly arrived vesicles are not release-ready. Notably, the rates of vesicle resupply and maturation of newcomers are among the fastest measured optically at any synapse. Lastly, our data show that the delay in vesicle departure increases and vesicle speed decreases with multiple stimuli. Our results support a role for ribbons in the supply of vesicles for release, provide direct measurements of vesicle movement down the ribbon, and suggest that multiple factors contribute to paired-pulse depression. Synaptic ribbons are macromolecular scaffolds that tether synaptic vesicles close to release sites in nonspiking neurons of the retina and cochlea. Because these neurons release neurotransmitter continuously, synaptic ribbons are assumed to act as platforms for supplying vesicles rapidly in the face of prolonged stimulation. Yet, ribbon synapses suffer from profound paired-pulse depression, which takes seconds to subside. We investigated the mechanistic origin of this phenomenon by directly imaging triggered vesicle movement and release at ribbon sites in retinal bipolar cells, and find that, although ribbon synapses deliver and prime vesicles faster than most conventional synapses, both vesicle absence and vesicle priming contribute to the long recovery from paired-pulse depression.
Topics: Animals; Cells, Cultured; Exocytosis; Female; Goldfish; Male; Neuronal Plasticity; Neurons; Synaptic Potentials; Synaptic Vesicles
PubMed: 32847965
DOI: 10.1523/JNEUROSCI.0605-20.2020 -
Advanced Materials (Deerfield Beach,... Mar 2024Nanoscale vesicles such as synaptic vesicles play a pivotal role in efficient interneuronal communications in vivo. However, the coexistence of single vesicle and...
Nanoscale vesicles such as synaptic vesicles play a pivotal role in efficient interneuronal communications in vivo. However, the coexistence of single vesicle and vesicle clusters in living cells increases the heterogeneity of vesicle populations, which largely complicates the quantitative analysis of the vesicles. The high spatiotemporal monitoring of vesicle assemblies is currently incompletely resolved. Here, this work uses synthetic vesicles and DNA nanorulers to reconstruct in vitro the vesicle assemblies that mimic vesicle clusters in living cells. DNA nanorulers program the lateral distance of vesicle assemblies from 3 to 10 nm. This work uses the carbon fiber nanoelectrode (CFNE) to amperometric monitor artificial vesicle assemblies with sub-10 nm interspaces, and obtain a larger proportion of complex events. This work resolves the heterogeneity of individual vesicle release kinetics in PC12 cells with the temporal resolution down to ≈0.1 ms. This work further analyzes the aggregation state of intracellular vesicles and the exocytosis of living cells with electrochemical vesicle cytometry. The results indicate that the exocytosis of vesicle clusters is critically dependent on the size of clusters. This technology has the potential as a tool to shed light on the heterogeneity analysis of vesicle populations.
Topics: Animals; Rats; Communication; DNA; Kinetics; PC12 Cells
PubMed: 37921116
DOI: 10.1002/adma.202308344 -
The Journal of Chemical Physics Jan 2019Langevin dynamics simulations are employed to study the shape transformation of a two-dimensional vesicle induced by active particles both inside and outside. We find...
Langevin dynamics simulations are employed to study the shape transformation of a two-dimensional vesicle induced by active particles both inside and outside. We find that the shape of the vesicle changes from circle, to capsule, and eventually to dumbbell with the enhancement of the particle activity. Under the cooperation between the inside and the outside active particles, such significant shape transformation is realized by tuning the activity in a small range. And unexpectedly, the fluctuations of the capsule and the dumbbell shapes are not completely random but mostly along the direction of the short axis. In the situation of strong activity, the inside of the dumbbell vesicle is analogous to a system of two chambers, which are connected by a narrow channel. Intriguingly, we observe the vibration of the channel width, accompanied with the exchange of active particles between the two chambers. We also find that dynamical manipulation of the vesicle shape is possible through tuning the particle activity dynamically. This work provides new ideas to the control of the vesicle morphology and new insights into the dynamics in the vesicle's shape transformation.
PubMed: 30709295
DOI: 10.1063/1.5078694 -
Medicine Mar 2019Solitary fibrous tumor (SFT) is an unusual neoplasm, especially when it originates from the seminal vesicle. Herein, we describe a case of SFT that arises from the...
RATIONALE
Solitary fibrous tumor (SFT) is an unusual neoplasm, especially when it originates from the seminal vesicle. Herein, we describe a case of SFT that arises from the seminal vesicle.
PATIENT CONCERNS
A 66-year-old man presented to our hospital complaining of a huge irregular tumor in his pelvis during a health checkup. He was worried that the tumor could be a malignant tumor and hence wanted to undergo further examination and therapy.
DIAGNOSIS
An inhomogeneous, mixed soft tissue tumor in the pelvis was found during computed tomography (CT) and magnetic resonance imaging. The tumor showed heterogeneous and delayed enhancement during contrast-enhanced CT. The tumor was diagnosed as a cystadenoma originated from the seminal vesicle due to its imaging features. But the pathological diagnosis was SFT that originated from the seminal vesicle.
INTERVENTIONS
Laparoscopic seminal vesicle tumor resection was performed.
OUTCOMES
There was no evidence of recurrence at the 6-month follow-up.
LESSONS
SFT in the seminal vesicle is extremely rare. It is very difficult to distinguish SFT in the seminal vesicle from the primary tumors as both have similar imaging features. We describe the tumor with SFT being considered as a differential diagnosis when the tumor is found in the seminal vesicle.
Topics: Aged; Genital Neoplasms, Male; Humans; Male; Seminal Vesicles; Solitary Fibrous Tumors
PubMed: 30817590
DOI: 10.1097/MD.0000000000014660 -
Cell Reports Feb 2017Vesicle sharing between synaptic boutons is an important component of the recycling process that synapses employ to maintain vesicle pools. However, the mechanisms...
Vesicle sharing between synaptic boutons is an important component of the recycling process that synapses employ to maintain vesicle pools. However, the mechanisms supporting and regulating vesicle transport during the inter-synaptic exchange remain poorly understood. Using nanometer-resolution tracking of individual synaptic vesicles and advanced computational algorithms, we find that long-distance axonal transport of synaptic vesicles between hippocampal boutons is partially mediated by the actin network, with myosin V as the primary actin-dependent motor that drives this vesicle transport. Furthermore, we find that vesicle exit from the synapse to the axon and long-distance vesicle transport are both rapidly and dynamically regulated by activity. We corroborated these findings with two complementary modeling approaches of vesicle exit, which closely reproduced experimental observations. These findings uncover the roles of actin and myosin V in supporting the inter-synaptic vesicle exchange and reveal that this process is dynamically modulated in an activity-dependent manner.
Topics: Actins; Animals; Axonal Transport; Axons; Cells, Cultured; Hippocampus; Myosin Type V; Neurons; Presynaptic Terminals; Rats; Synapses; Synaptic Transmission; Synaptic Vesicles
PubMed: 28249156
DOI: 10.1016/j.celrep.2017.02.010