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Yakugaku Zasshi : Journal of the... May 2008The mechanism of vesicle-to-micelle or micelle-to-vesicle transition was studied in order to control sizes and fluidities of vesicles during periods of preparation.... (Review)
Review
The mechanism of vesicle-to-micelle or micelle-to-vesicle transition was studied in order to control sizes and fluidities of vesicles during periods of preparation. Dependence of particle sizes measured by quasi-elastic light scattering, turbidities, fluidity parameters monitored by ESR spectroscopy, and morphological changes of mixed aggregates of egg yolk phosphatidylcholine (EPC) and a detergent (octylglucoside (OG) or sodium cholate (Na-chol)) on detergent concentration provided a model of vesicle destruction. It possessed three phase transition points, and proceeded in a stepwise fashion: vesicles, small particles containing large amounts of detergents (SUV(*)), intermediate structures, and mixed micelles. Vesicle formation on removal of detergents from micelles proceeded oppositely. Micelle-vesicle transition mechanism was common to all detergents examined. The feature of the mechanism was the presence of SUV(*). Next, SUV(*) was prepared by adding appropriate amount of a detergent to small unilamellar vesicles obtained by sonication. Time-dependent size growth of the SUV(*) was remarkable in the case of OG-containing SUV(*), but was insignificant in the case of Na-chol-containing SUV(*), suggesting the size determining step to be the stage of the SUV(*). The tendency to produce large or small vesicles from micelles was related to the absence or presence, respectively, of a net charge in the detergent molecule. The fluidities of EPC micelles containing small amounts of a detergent possessing a steroidal structure (e.g., Na-chol or CHAPS) were significantly smaller than the corresponding values of a detergent without a steroidal structure (e.g., OG), suggesting a method of control of orderliness of hydrocarbon chains in EPC vesicles.
Topics: Detergents; Egg Yolk; Glucosides; Liposomes; Membrane Fluidity; Micelles; Particle Size; Phosphatidylcholines; Transport Vesicles
PubMed: 18451612
DOI: 10.1248/yakushi.128.669 -
Microbiology Spectrum Mar 2023Outer membrane vesicles (OMVs) are a primary means of communication for Gram-negative bacteria. The specific role of vesicle components in cellular communication and how...
Outer membrane vesicles (OMVs) are a primary means of communication for Gram-negative bacteria. The specific role of vesicle components in cellular communication and how components are packaged are still under investigation, but a correlation exists between OMV biogenesis and content. The two primary mechanisms of OMV biogenesis are membrane blebbing and explosive cell lysis, and vesicle content is based on the biogenesis mechanism. Hypervesiculation, which can be induced by stress conditions, also influences OMV content. Norovirus interaction with Enterobacter cloacae induces stress responses leading to increased OMV production and changes in DNA content, protein content, and vesicle size. The presence of genomic DNA and cytoplasmic proteins in these OMVs suggests some of the vesicles are formed by explosive cell lysis, so reduction or loss of these components indicates a shift away from this mechanism of biogenesis. Based on this, further investigation into bacterial stability and OMV content was conducted. Results showed that norovirus induced a dramatic shift in OMV lipid content. Specifically, the increased accumulation of phospholipids is associated with increased blebbing, thereby supporting previous observations that noroviruses shift the mechanism of OMV biogenesis. Slight differences in OMV metabolite content were also observed. While norovirus induced changes in OMV content, it did not change the lipid content of the bacterial outer membrane or the metabolite content of the bacterial cell. Overall, these results indicate that norovirus induces significant changes to OMV lipid architecture and cargo, which may be linked to a change in the mechanism of vesicle biogenesis. Extracellular vesicles from commensal bacteria are recognized for their importance in modulating host immune responses, and vesicle content is related to their impact on the host. Therefore, understanding how vesicles are formed and how their content shifts in response to stress conditions is necessary for elucidating their downstream functions. Our recent work has demonstrated that interactions between noroviruses and Enterobacter cloacae induce bacterial stress responses leading to hypervesiculation. In this article, we characterize and compare the lipid and metabolomic cargo of E. cloacae vesicles generated in the presence and absence of norovirus and show that viral interactions induce significant changes in vesicle content. Furthermore, we probe how these changes and changes to the bacterial cell may be indicative of a shift in the mechanism of vesicle biogenesis. Importantly, we find that noroviruses induce significant changes in vesicle lipid architecture and cargo that may be responsible for the immunogenic activity of these vesicles.
PubMed: 36943087
DOI: 10.1128/spectrum.04691-22 -
Small GTPases Jan 2017The intracellular movement of membrane-bound vesicles is closely tied to their formation, maturation and ultimate function within the cell. Motor proteins and their...
The intracellular movement of membrane-bound vesicles is closely tied to their formation, maturation and ultimate function within the cell. Motor proteins and their associated cytoskeletal networks are critical for vesicle transport, but whether these factors play a more direct role in vesicle biogenesis is unclear. In recent work, we found that the Drosophila kinesin proteins Khc and Klp98A are both required for the normal anterograde movement of autophagosomes and autolysosomes during starvation-induced autophagy. In addition, Klp98A has a transport-independent function of promoting autophagosome-lysosome fusion, a key step in the maturation of autophagic vesicles. This function correlates with the association of Klp98A with the autophagosomal protein Atg8 and with the endolysosomal protein Rab14, suggesting that Klp98A may promote vesicle fusion by physically linking these vesicle surface proteins. These findings demonstrate how the delivery of vesicles to their proper destination can be coordinated with additional steps in their life cycle through molecular motor-based interactions.
Topics: Animals; Autophagosomes; Autophagy; Drosophila; Drosophila Proteins; Kinesins; Lysosomes; Membrane Fusion; rab GTP-Binding Proteins
PubMed: 27142690
DOI: 10.1080/21541248.2016.1184776 -
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 -
Advances in Experimental Medicine and... 2019Astrocytes are secretory cells, actively participating in cell-to-cell communication in the central nervous system (CNS). They sense signaling molecules in the... (Review)
Review
Astrocytes are secretory cells, actively participating in cell-to-cell communication in the central nervous system (CNS). They sense signaling molecules in the extracellular space, around the nearby synapses and also those released at much farther locations in the CNS, by their cell surface receptors, get excited to then release their own signaling molecules. This contributes to the brain information processing, based on diffusion within the extracellular space around the synapses and on convection when locales relatively far away from the release sites are involved. These functions resemble secretion from endocrine cells, therefore astrocytes were termed to be a part of the gliocrine system in 2015. An important mechanism, by which astrocytes release signaling molecules is the merger of the vesicle membrane with the plasmalemma, i.e., exocytosis. Signaling molecules stored in astroglial secretory vesicles can be discharged into the extracellular space after the vesicle membrane fuses with the plasma membrane. This leads to a fusion pore formation, a channel that must widen to allow the exit of the Vesiclal cargo. Upon complete vesicle membrane fusion, this process also integrates other proteins, such as receptors, transporters and channels into the plasma membrane, determining astroglial surface signaling landscape. Vesiclal cargo, together with the whole vesicle can also exit astrocytes by the fusion of multivesicular bodies with the plasma membrane (exosomes) or by budding of vesicles (ectosomes) from the plasma membrane into the extracellular space. These astroglia-derived extracellular vesicles can later interact with various target cells. Here, the characteristics of four types of astroglial secretory vesicles: synaptic-like microvesicles, dense-core vesicles, secretory lysosomes, and extracellular vesicles, are discussed. Then machinery for vesicle-based exocytosis, second messenger regulation and the kinetics of exocytotic vesicle content discharge or release of extracellular vesicles are considered. In comparison to rapidly responsive, electrically excitable neurons, the receptor-mediated cytosolic excitability-mediated astroglial exocytotic vesicle-based transmitter release is a relatively slow process.
Topics: Astrocytes; Central Nervous System; Exocytosis; Humans; Membrane Fusion; Secretory Vesicles
PubMed: 31583585
DOI: 10.1007/978-981-13-9913-8_4 -
ELife Oct 2021The Ca-dependence of the priming, fusion, and replenishment of synaptic vesicles are fundamental parameters controlling neurotransmitter release and synaptic plasticity....
The Ca-dependence of the priming, fusion, and replenishment of synaptic vesicles are fundamental parameters controlling neurotransmitter release and synaptic plasticity. Despite intense efforts, these important steps in the synaptic vesicles' cycle remain poorly understood due to the technical challenge in disentangling vesicle priming, fusion, and replenishment. Here, we investigated the Ca-sensitivity of these steps at mossy fiber synapses in the rodent cerebellum, which are characterized by fast vesicle replenishment mediating high-frequency signaling. We found that the basal free Ca concentration (<200 nM) critically controls action potential-evoked release, indicating a high-affinity Ca sensor for vesicle priming. Ca uncaging experiments revealed a surprisingly shallow and non-saturating relationship between release rate and intracellular Ca concentration up to 50 μM. The rate of vesicle replenishment during sustained elevated intracellular Ca concentration exhibited little Ca-dependence. Finally, quantitative mechanistic release schemes with five Ca binding steps incorporating rapid vesicle replenishment via parallel or sequential vesicle pools could explain our data. We thus show that co-existing high- and low-affinity Ca sensors mediate priming, fusion, and replenishment of synaptic vesicles at a high-fidelity synapse.
Topics: Animals; Biological Transport; Calcium; Cerebellum; Female; Male; Mice; Mice, Inbred C57BL; Neurons; Neurotransmitter Agents; Synapses; Synaptic Transmission; Synaptic Vesicles
PubMed: 34612812
DOI: 10.7554/eLife.70408 -
Human Molecular Genetics Apr 2014Mutations in the dysferlin gene resulting in dysferlin-deficiency lead to limb-girdle muscular dystrophy 2B and Myoshi myopathy in humans. Dysferlin has been proposed as...
Mutations in the dysferlin gene resulting in dysferlin-deficiency lead to limb-girdle muscular dystrophy 2B and Myoshi myopathy in humans. Dysferlin has been proposed as a critical regulator of vesicle-mediated membrane resealing in muscle fibers, and localizes to muscle fiber wounds following sarcolemma damage. Studies in fibroblasts and urchin eggs suggest that trafficking and fusion of intracellular vesicles with the plasma membrane during resealing requires the intracellular cytoskeleton. However, the contribution of dysferlin-containing vesicles to resealing in muscle and the role of the cytoskeleton in regulating dysferlin-containing vesicle biology is unclear. Here, we use live-cell imaging to examine the behavior of dysferlin-containing vesicles following cellular wounding in muscle cells and examine the role of microtubules and kinesin in dysferlin-containing vesicle behavior following wounding. Our data indicate that dysferlin-containing vesicles move along microtubules via the kinesin motor KIF5B in muscle cells. Membrane wounding induces dysferlin-containing vesicle-vesicle fusion and the formation of extremely large cytoplasmic vesicles, and this response depends on both microtubules and functional KIF5B. In non-muscle cell types, lysosomes are critical mediators of membrane resealing, and our data indicate that dysferlin-containing vesicles are capable of fusing with lysosomes following wounding which may contribute to formation of large wound sealing vesicles in muscle cells. Overall, our data provide mechanistic evidence that microtubule-based transport of dysferlin-containing vesicles may be critical for resealing, and highlight a critical role for dysferlin-containing vesicle-vesicle and vesicle-organelle fusion in response to wounding in muscle cells.
Topics: Animals; Cell Line; Cell Membrane; Cytoplasmic Vesicles; Green Fluorescent Proteins; Heterocyclic Compounds, 4 or More Rings; Kinesins; Lysosomes; Membrane Fusion; Membrane Proteins; Microtubules; Muscle Cells; Muscle Fibers, Skeletal; Muscle Proteins; Muscle, Skeletal; Muscular Dystrophies, Limb-Girdle; Myosin Type II; Nocodazole; Rats; Tubulin Modulators
PubMed: 24203699
DOI: 10.1093/hmg/ddt557 -
Frontiers in Synaptic Neuroscience 2016Neurotransmitter is released from synaptic vesicles at the highly specialized presynaptic active zone (AZ). The complex molecular architecture of AZs mediates the speed,...
Neurotransmitter is released from synaptic vesicles at the highly specialized presynaptic active zone (AZ). The complex molecular architecture of AZs mediates the speed, precision and plasticity of synaptic transmission. Importantly, structural and functional properties of AZs vary significantly, even for a given connection. Thus, there appear to be distinct AZ states, which fundamentally influence neuronal communication by controlling the positioning and release of synaptic vesicles. Vice versa, recent evidence has revealed that synaptic vesicle components also modulate organizational states of the AZ. The protein-rich cytomatrix at the active zone (CAZ) provides a structural platform for molecular interactions guiding vesicle exocytosis. Studies in Drosophila have now demonstrated that the vesicle proteins Synaptotagmin-1 (Syt1) and Rab3 also regulate glutamate release by shaping differentiation of the CAZ ultrastructure. We review these unexpected findings and discuss mechanistic interpretations of the reciprocal relationship between synaptic vesicles and AZ states, which has heretofore received little attention.
PubMed: 27148040
DOI: 10.3389/fnsyn.2016.00008 -
Asian Journal of Andrology 2019We aimed to establish a novel rat model of seminal vesiculitis that would provide an effective approach to investigate the pathogenesis of this disease in the future....
We aimed to establish a novel rat model of seminal vesiculitis that would provide an effective approach to investigate the pathogenesis of this disease in the future. Eight male rats received the same operation, during which the root of one of the two seminal vesicles was partly ligatured with sutures and the other vesicle was left intact. The samples of seminal vesicles were harvested on the 8 day following the operation. Hematoxylin and eosin and Masson's trichrome stains were used to observe the histopathology and the presence of fibrous tissue in seminal vesicles, respectively. Immunoblotting and immunohistochemistry were applied to determine the tumor necrosis factor-alpha and cyclooxygenase-2 levels in seminal vesicle tissues. Real-time fluorescence quantitative polymerase chain reaction was performed to measure the gene expression levels of proinflammatory cytokines. HOlevelsin the seminal plasma from the seminal vesicle were also measured. Hematoxylin and eosin staining suggested that there was inflammatory cell infiltration into the seminal vesicles treated by partial root ligation. The tumor necrosis factor-alpha and cyclooxygenase-2 proteins were significantly upregulated in the treated seminal vesicles. The tumor necrosis factor-alpha, cyclooxygenase, interleukin 6, and inducible nitric oxide synthase mRNA expression levels were also upregulated in the treated seminal vesicles. The HO levels in the seminal plasma from seminal vesicles with partial root ligation were significantly elevated compared with those from vesicle left intact. In conclusion, partially ligating the root of the seminal vesicle via sutures in rats is an effective method to establish a seminal vesiculitis rat model.
Topics: Animals; Cyclooxygenase 2; Disease Models, Animal; Genital Diseases, Male; Inflammation; Male; Rats; Rats, Sprague-Dawley; Seminal Vesicles; Tumor Necrosis Factor-alpha
PubMed: 30460934
DOI: 10.4103/aja.aja_90_18 -
Journal of Parkinson's Disease 2021Recent data support an involvement of defects in homeostasis of phosphoinositides (PIPs) in the pathophysiology of Parkinson's disease (PD). Genetic mutations have been... (Review)
Review
Recent data support an involvement of defects in homeostasis of phosphoinositides (PIPs) in the pathophysiology of Parkinson's disease (PD). Genetic mutations have been identified in genes encoding for PIP-regulating and PIP-interacting proteins, that are associated with familial and sporadic PD. Many of these proteins are implicated in vesicular membrane trafficking, mechanisms that were recently highlighted for their close associations with PD. PIPs are phosphorylated forms of the membrane phospholipid, phosphatidylinositol. Their composition in the vesicle's membrane of origin, as well as membrane of destination, controls vesicular membrane trafficking. We review the converging evidence that points to the involvement of PIPs in PD. The review describes PD- and PIP-associated proteins implicated in clathrin-mediated endocytosis and autophagy, and highlights the involvement of α-synuclein in these mechanisms.
Topics: Autophagy; Endocytosis; Humans; Parkinson Disease; Phosphatidylinositols; alpha-Synuclein
PubMed: 34151859
DOI: 10.3233/JPD-212684