The Experts below are selected from a list of 129132 Experts worldwide ranked by ideXlab platform
Martin Oheim - One of the best experts on this subject based on the ideXlab platform.
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astrocyte vamp3 Vesicles undergo ca2 independent cycling and modulate glutamate transporter trafficking
The Journal of Physiology, 2015Co-Authors: Karine Herault, Kathleen Zylbersztejn, Martin Oheim, Marcel A. Lauterbach, Marc Guillon, Dongdong LiAbstract:Key points Mouse cortical astrocytes express VAMP3 but not VAMP2. VAMP3 Vesicles undergo Ca2+-independent exo- and endocytotic cycling at the plasma membrane. VAMP3 Vesicle traffic regulates the recycling of plasma membrane glutamate transporters. cAMP modulates VAMP3 Vesicle cycling and glutamate uptake. Abstract Previous studies suggest that small synaptic-like Vesicles in astrocytes carry Vesicle-associated vSNARE proteins, VAMP3 (cellubrevin) and VAMP2 (synaptobrevin 2), both contributing to the Ca2+-regulated exocytosis of gliotransmitters, thereby modulating brain information processing. Here, using cortical astrocytes taken from VAMP2 and VAMP3 knock-out mice, we find that astrocytes express only VAMP3. The morphology and function of VAMP3 Vesicles were studied in cultured astrocytes at single Vesicle level with stimulated emission depletion (STED) and total internal reflection fluorescence (TIRF) microscopies. We show that VAMP3 antibodies label small diameter (∼80 nm) Vesicles and that VAMP3 Vesicles undergo Ca2+-independent exo-endocytosis. We also show that this pathway modulates the surface expression of plasma membrane glutamate transporters and the glutamate uptake by astrocytes. Finally, using pharmacological and optogenetic tools, we provide evidence suggesting that the cytosolic cAMP level influences astrocytic VAMP3 Vesicle trafficking and glutamate transport. Our results suggest a new role for VAMP3 Vesicles in astrocytes.
Kathleen Zylbersztejn - One of the best experts on this subject based on the ideXlab platform.
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astrocyte vamp3 Vesicles undergo ca2 independent cycling and modulate glutamate transporter trafficking
The Journal of Physiology, 2015Co-Authors: Karine Herault, Kathleen Zylbersztejn, Martin Oheim, Marcel A. Lauterbach, Marc Guillon, Dongdong LiAbstract:Key points Mouse cortical astrocytes express VAMP3 but not VAMP2. VAMP3 Vesicles undergo Ca2+-independent exo- and endocytotic cycling at the plasma membrane. VAMP3 Vesicle traffic regulates the recycling of plasma membrane glutamate transporters. cAMP modulates VAMP3 Vesicle cycling and glutamate uptake. Abstract Previous studies suggest that small synaptic-like Vesicles in astrocytes carry Vesicle-associated vSNARE proteins, VAMP3 (cellubrevin) and VAMP2 (synaptobrevin 2), both contributing to the Ca2+-regulated exocytosis of gliotransmitters, thereby modulating brain information processing. Here, using cortical astrocytes taken from VAMP2 and VAMP3 knock-out mice, we find that astrocytes express only VAMP3. The morphology and function of VAMP3 Vesicles were studied in cultured astrocytes at single Vesicle level with stimulated emission depletion (STED) and total internal reflection fluorescence (TIRF) microscopies. We show that VAMP3 antibodies label small diameter (∼80 nm) Vesicles and that VAMP3 Vesicles undergo Ca2+-independent exo-endocytosis. We also show that this pathway modulates the surface expression of plasma membrane glutamate transporters and the glutamate uptake by astrocytes. Finally, using pharmacological and optogenetic tools, we provide evidence suggesting that the cytosolic cAMP level influences astrocytic VAMP3 Vesicle trafficking and glutamate transport. Our results suggest a new role for VAMP3 Vesicles in astrocytes.
Dongdong Li - One of the best experts on this subject based on the ideXlab platform.
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astrocyte vamp3 Vesicles undergo ca2 independent cycling and modulate glutamate transporter trafficking
The Journal of Physiology, 2015Co-Authors: Karine Herault, Kathleen Zylbersztejn, Martin Oheim, Marcel A. Lauterbach, Marc Guillon, Dongdong LiAbstract:Key points Mouse cortical astrocytes express VAMP3 but not VAMP2. VAMP3 Vesicles undergo Ca2+-independent exo- and endocytotic cycling at the plasma membrane. VAMP3 Vesicle traffic regulates the recycling of plasma membrane glutamate transporters. cAMP modulates VAMP3 Vesicle cycling and glutamate uptake. Abstract Previous studies suggest that small synaptic-like Vesicles in astrocytes carry Vesicle-associated vSNARE proteins, VAMP3 (cellubrevin) and VAMP2 (synaptobrevin 2), both contributing to the Ca2+-regulated exocytosis of gliotransmitters, thereby modulating brain information processing. Here, using cortical astrocytes taken from VAMP2 and VAMP3 knock-out mice, we find that astrocytes express only VAMP3. The morphology and function of VAMP3 Vesicles were studied in cultured astrocytes at single Vesicle level with stimulated emission depletion (STED) and total internal reflection fluorescence (TIRF) microscopies. We show that VAMP3 antibodies label small diameter (∼80 nm) Vesicles and that VAMP3 Vesicles undergo Ca2+-independent exo-endocytosis. We also show that this pathway modulates the surface expression of plasma membrane glutamate transporters and the glutamate uptake by astrocytes. Finally, using pharmacological and optogenetic tools, we provide evidence suggesting that the cytosolic cAMP level influences astrocytic VAMP3 Vesicle trafficking and glutamate transport. Our results suggest a new role for VAMP3 Vesicles in astrocytes.
Remco Nieuwland - One of the best experts on this subject based on the ideXlab platform.
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Particle size distribution of exosomes and microVesicles determined by transmission electron microscopy, flow cytometry, nanoparticle tracking analysis, and resistive pulse sensing
Journal of Thrombosis and Haemostasis, 2014Co-Authors: E. Van Der Pol, Frank A W Coumans, Auguste Sturk, Cameron Gardiner, Ian L. Sargent, P. Harrison, Ton G. Van Leeuwen, Anita E Grootemaat, Remco NieuwlandAbstract:BACKGROUND: Enumeration of extracellular Vesicles has clinical potential as a biomarker for disease. In biological samples, the smallest and largest Vesicles typically differ 25-fold in size, 300 000-fold in concentration, 20 000-fold in volume, and 10 000 000-fold in scattered light. Because of this heterogeneity, the currently employed techniques detect concentrations ranging from 10(4) to 10(12) Vesicles mL(-1) .\n\nOBJECTIVES: To investigate whether the large variation in the detected concentration of Vesicles is caused by the minimum detectable Vesicle size of five widely used techniques.\n\nMETHODS: The size and concentration of Vesicles and reference beads were measured with transmission electron microscopy (TEM), a conventional flow cytometer, a flow cytometer dedicated to detecting submicrometer particles, nanoparticle tracking analysis (NTA), and resistive pulse sensing (RPS).\n\nRESULTS: Each technique gave a different size distribution and a different concentration for the same Vesicle sample.\n\nCONCLUSION: Differences between the detected Vesicle concentrations are primarily caused by differences between the minimum detectable Vesicle sizes. The minimum detectable Vesicle sizes were 70-90 nm for NTA, 70-100 nm for RPS, 150-190 nm for dedicated flow cytometry, and 270-600 nm for conventional flow cytometry. TEM could detect the smallest Vesicles present, albeit after adhesion on a surface. Dedicated flow cytometry was most accurate in determining the size of reference beads, but is expected to be less accurate on Vesicles, owing to heterogeneity of the refractive index of Vesicles. Nevertheless, dedicated flow cytometry is relatively fast and allows multiplex fluorescence detection, making it most applicable to clinical research.
Meta J Kuehn - One of the best experts on this subject based on the ideXlab platform.
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Quantitative and qualitative preparations of bacterial outer membrane Vesicles.
Methods in Molecular Biology, 2012Co-Authors: Halima Chutkan, Ian A. Macdonald, Andrew J. Manning, Meta J KuehnAbstract:Gram-negative bacterial outer membrane Vesicle production and function have been studied using a variety of quantitative and qualitative methods. These types of analyses can be hampered by the use of impure Vesicle preparations. Here we describe a set of techniques that are useful for the quantitative analysis of Vesicle production and for preparative yields of highly purified Vesicles for studies of Vesicle function or composition. Procedures and advice are also included for the purification of Vesicles from encapsulated and low-yield strains.
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naturally produced outer membrane Vesicles from pseudomonas aeruginosa elicit a potent innate immune response via combined sensing of both lipopolysaccharide and protein components
Infection and Immunity, 2010Co-Authors: Terri N Ellis, Sara A Leiman, Meta J KuehnAbstract:Pseudomonas aeruginosa is a prevalent opportunistic human pathogen that, like other Gram-negative pathogens, secretes outer membrane Vesicles. Vesicles are complex entities composed of a subset of envelope lipid and protein components that have been observed to interact with and be internalized by host cells. This study characterized the inflammatory responses to naturally produced P. aeruginosa Vesicles and determined the contribution of Vesicle Toll-like receptor (TLR) ligands and Vesicle proteins to that response. Analysis of macrophage responses to purified Vesicles by real-time PCR and enzyme-linked immunosorbent assay identified proinflammatory cytokines upregulated by Vesicles. Intact Vesicles were shown to elicit a profoundly greater inflammatory response than the response to purified lipopolysaccharide (LPS). Both TLR ligands LPS and flagellin contributed to specific Vesicle cytokine responses, whereas the CpG DNA content of Vesicles did not. Neutralization of LPS sensing demonstrated that macrophage responses to the protein composition of Vesicles required the adjuvantlike activity of LPS to elicit strain specific responses. Protease treatment to remove proteins from the Vesicle surface resulted in decreased interleukin-6 and tumor necrosis factor alpha production, indicating that the production of these specific cytokines may be linked to macrophage recognition of Vesicle proteins. Confocal microscopy of Vesicle uptake by macrophages revealed that Vesicle LPS allows for binding to macrophage surfaces, whereas Vesicle protein content is required for internalization. These data demonstrate that macrophage sensing of both LPS and protein components of outer membrane Vesicles combine to produce a bacterial strain-specific response that is distinct from those triggered by individual, purified Vesicle components.
