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Cell Stem Cell Oct 2021During embryogenesis, optic vesicles develop from the diencephalon via a multistep process of organogenesis. Using induced pluripotent stem cell (iPSC)-derived human...
During embryogenesis, optic vesicles develop from the diencephalon via a multistep process of organogenesis. Using induced pluripotent stem cell (iPSC)-derived human brain organoids, we attempted to simplify the complexities and demonstrate formation of forebrain-associated bilateral optic vesicles, cellular diversity, and functionality. Around day 30, brain organoids attempt to assemble optic vesicles, which develop progressively as visible structures within 60 days. These optic vesicle-containing brain organoids (OVB-organoids) constitute a developing optic vesicle's cellular components, including primitive corneal epithelial and lens-like cells, retinal pigment epithelia, retinal progenitor cells, axon-like projections, and electrically active neuronal networks. OVB-organoids also display synapsin-1, CTIP-positive myelinated cortical neurons, and microglia. Interestingly, various light intensities could trigger photosensitive activity of OVB-organoids, and light sensitivities could be reset after transient photobleaching. Thus, brain organoids have the intrinsic ability to self-organize forebrain-associated primitive sensory structures in a topographically restricted manner and can allow interorgan interaction studies within a single organoid.
Topics: Cell Differentiation; Embryonic Development; Humans; Induced Pluripotent Stem Cells; Organogenesis; Organoids; Prosencephalon
PubMed: 34407456
DOI: 10.1016/j.stem.2021.07.010 -
Environmental Science & Technology Jun 2022Recent discovery of vesicle-cloaked virus clusters (i.e., viral vesicles) has greatly challenged the central paradigm of viral transmission and infection as a single...
Recent discovery of vesicle-cloaked virus clusters (i.e., viral vesicles) has greatly challenged the central paradigm of viral transmission and infection as a single virion. To understand the environmental transmission of viral vesicles, we used an in vivo model to investigate their environmental persistence and engineering control by disinfection. Murine rotavirus vesicles maintained both their integrity and infectivity after incubation in filtered freshwater and wastewater for at least 7 days, with 24.5-27.5% of the vesicles still intact at 16 weeks after exposure to both waters. Free chlorine disinfection at a dosage of 13.3 mg min L did not decompose murine rotavirus vesicles, and it was much less effective in inactivating rotaviruses inside vesicles than free rotaviruses based on the quantification of rotavirus shedding in mouse stool and rotavirus replication in small intestines. Rotavirus vesicles may be more environmentally transmissible than free rotaviruses regardless of disinfection. Vesicle-mediated transmission could be responsible for vesicles' resistance to disinfection due to an increased multiplicity of infection and/or genetic recombination or reassortment to promote infection. Our work highlights the environmental, biological, and public health significance of viral vesicles, and the findings call for urgent action in advancing disinfection for pathogen control.
Topics: Animals; Chlorine; Disinfection; Feces; Mice; Rotavirus; Wastewater
PubMed: 35653550
DOI: 10.1021/acs.est.2c00732 -
Cells Jun 2020Cellular secretion depends on exocytosis of secretory vesicles and discharge of vesicle contents. Actin and myosin are essential for pre-fusion and post-fusion stages of... (Review)
Review
Cellular secretion depends on exocytosis of secretory vesicles and discharge of vesicle contents. Actin and myosin are essential for pre-fusion and post-fusion stages of exocytosis. Secretory vesicles depend on actin for transport to and attachment at the cell cortex during the pre-fusion phase. Actin coats on fused vesicles contribute to stabilization of large vesicles, active vesicle contraction and/or retrieval of excess membrane during the post-fusion phase. Myosin molecular motors complement the role of actin. Myosin V is required for vesicle trafficking and attachment to cortical actin. Myosin I and II members engage in local remodeling of cortical actin to allow vesicles to get access to the plasma membrane for membrane fusion. Myosins stabilize open fusion pores and contribute to anchoring and contraction of actin coats to facilitate vesicle content release. Actin and myosin function in secretion is regulated by a plethora of interacting regulatory lipids and proteins. Some of these processes have been first described in non-neuronal cells and reflect adaptations to exocytosis of large secretory vesicles and/or secretion of bulky vesicle cargoes. Here we collate the current knowledge and highlight the role of actomyosin during distinct phases of exocytosis in an attempt to identify unifying molecular mechanisms in non-neuronal secretory cells.
Topics: Actin Cytoskeleton; Actins; Animals; Exocytosis; Humans; Membrane Fusion; Myosins; Secretory Vesicles
PubMed: 32545391
DOI: 10.3390/cells9061455 -
Cold Spring Harbor Perspectives in... Sep 2012Neurons can sustain high rates of synaptic transmission without exhausting their supply of synaptic vesicles. This property relies on a highly efficient local endocytic... (Review)
Review
Neurons can sustain high rates of synaptic transmission without exhausting their supply of synaptic vesicles. This property relies on a highly efficient local endocytic recycling of synaptic vesicle membranes, which can be reused for hundreds, possibly thousands, of exo-endocytic cycles. Morphological, physiological, molecular, and genetic studies over the last four decades have provided insight into the membrane traffic reactions that govern this recycling and its regulation. These studies have shown that synaptic vesicle endocytosis capitalizes on fundamental and general endocytic mechanisms but also involves neuron-specific adaptations of such mechanisms. Thus, investigations of these processes have advanced not only the field of synaptic transmission but also, more generally, the field of endocytosis. This article summarizes current information on synaptic vesicle endocytosis with an emphasis on the underlying molecular mechanisms and with a special focus on clathrin-mediated endocytosis, the predominant pathway of synaptic vesicle protein internalization.
Topics: Actin Cytoskeleton; Clathrin; Clathrin-Coated Vesicles; Endocytosis; Exocytosis; Intracellular Membranes; Membrane Fusion; Models, Biological; Phosphatidylinositols; Protein Transport; Synaptic Transmission; Synaptic Vesicles
PubMed: 22763746
DOI: 10.1101/cshperspect.a005645 -
Journal of Thrombosis and Haemostasis :... Jul 2014Enumeration of extracellular vesicles has clinical potential as a biomarker for disease. In biological samples, the smallest and largest vesicles typically differ...
Particle size distribution of exosomes and microvesicles determined by transmission electron microscopy, flow cytometry, nanoparticle tracking analysis, and resistive pulse sensing.
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) .
OBJECTIVES
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.
METHODS
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).
RESULTS
Each technique gave a different size distribution and a different concentration for the same vesicle sample.
CONCLUSION
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.
Topics: Biomarkers; Cell-Derived Microparticles; Exosomes; Flow Cytometry; Humans; Microscopy, Electron, Transmission; Nanoparticles; Optics and Photonics; Particle Size; Refractometry; Reproducibility of Results
PubMed: 24818656
DOI: 10.1111/jth.12602 -
The Japanese Dental Science Review May 2017Matrix vesicle-mediated mineralization is an orchestrated sequence of ultrastructural and biochemical events that lead to crystal nucleation and growth. The influx of... (Review)
Review
Matrix vesicle-mediated mineralization is an orchestrated sequence of ultrastructural and biochemical events that lead to crystal nucleation and growth. The influx of phosphate ions into the matrix vesicle is mediated by several proteins such as TNAP, ENPP1, Pit1, annexin and so forth. The catalytic activity of ENPP1 generates pyrophosphate (PPi) using extracellular ATPs as a substrate, and the resultant PPi prevents crystal overgrowth. However, TNAP hydrolyzes PPi into phosphate ion monomers, which are then transported into the matrix vesicle through Pit1. Accumulation of Ca and PO inside matrix vesicles then induces crystalline nucleation, with calcium phosphate crystals budding off radially, puncturing the matrix vesicle's membrane and finally growing out of it to form mineralized nodules.
PubMed: 28479934
DOI: 10.1016/j.jdsr.2016.09.002 -
FEBS Letters Mar 2023COPI-coated vesicles mediate transport between Golgi stacks and retrograde transport from the Golgi to the endoplasmic reticulum. The COPI coat exists as a stable... (Review)
Review
COPI-coated vesicles mediate transport between Golgi stacks and retrograde transport from the Golgi to the endoplasmic reticulum. The COPI coat exists as a stable heptameric complex in the cytosol termed coatomer and is recruited en bloc to the membrane for vesicle formation. Recruitment of COPI onto membranes is mediated by the Arf family of small GTPases, which, in their GTP-bound state, bind both membrane and coatomer. Arf GTPases also influence cargo selection, vesicle scission and vesicle uncoating. Guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) regulate nucleotide binding by Arf GTPases. To understand the mechanism of COPI-coated vesicle trafficking, it is necessary to characterize the interplay between coatomer and Arf GTPases and their effectors. It is also necessary to understand interactions between coatomer and cargo, cargo adaptors/receptors and tethers facilitating binding to the target membrane. Here, we summarize current knowledge of COPI coat protein structure; we describe how structural and biochemical studies contributed to this knowledge; we review mechanistic insights into COPI vesicle biogenesis and disassembly; and we discuss the potential to answer open questions in the field.
Topics: Humans; ADP-Ribosylation Factors; Carrier Proteins; COP-Coated Vesicles; Enzyme Activation; GTPase-Activating Proteins; Guanine Nucleotide Exchange Factors; Substrate Specificity
PubMed: 36513395
DOI: 10.1002/1873-3468.14560 -
International Journal of Molecular... Sep 2022Bone mineralization entails two mineralization phases: primary and secondary mineralization. Primary mineralization is achieved when matrix vesicles are secreted by... (Review)
Review
Bone mineralization entails two mineralization phases: primary and secondary mineralization. Primary mineralization is achieved when matrix vesicles are secreted by osteoblasts, and thereafter, bone mineral density gradually increases during secondary mineralization. Nearby extracellular phosphate ions (PO) flow into the vesicles via membrane transporters and enzymes located on the vesicles' membranes, while calcium ions (Ca), abundant in the tissue fluid, are also transported into the vesicles. The accumulation of Ca and PO in the matrix vesicles induces crystal nucleation and growth. The calcium phosphate crystals grow radially within the vesicle, penetrate the vesicle's membrane, and continue to grow outside the vesicle, ultimately forming mineralized nodules. The mineralized nodules then attach to collagen fibrils, mineralizing them from the contact sites (i.e., collagen mineralization). Afterward, the bone mineral density gradually increases during the secondary mineralization process. The mechanisms of this phenomenon remain unclear, but osteocytes may play a key role; it is assumed that osteocytes enable the transport of Ca and PO through the canaliculi of the osteocyte network, as well as regulate the mineralization of the surrounding bone matrix via the Phex/SIBLINGs axis. Thus, bone mineralization is biologically regulated by osteoblasts and osteocytes.
Topics: Bone Matrix; Calcification, Physiologic; Collagen; Extracellular Matrix; Osteoblasts; Osteocytes
PubMed: 36077336
DOI: 10.3390/ijms23179941 -
Journal of Biosciences 2022Eukaryotic cells use small membrane-enclosed vesicles to transport molecular cargo between intracellular compartments. Interactions between molecules on vesicles and...
Eukaryotic cells use small membrane-enclosed vesicles to transport molecular cargo between intracellular compartments. Interactions between molecules on vesicles and compartments determine the source and target compartment of each vesicle type. The set of compartment and vesicle types in a cell define the nodes and edges of a transport graph known as the vesicle traffic network. The transmembrane SNARE proteins that regulate vesicle fusion to target compartments travel in cycles through the transport graph, but the paths they follow must be tightly regulated to avoid aberrant vesicle fusion. Here we use graph-theoretic ideas to understand how such molecular constraints place constraints on the structure of the transport graph. We identify edge connectivity (the minimum number of edges that must be removed to disconnect a graph) as a key determinant that separates allowed and disallowed types of transport graphs. As we increase the flexibility of molecular regulation, the required edge connectivity decreases, so more types of vesicle transport graphs are allowed. These results can be used to aid the discovery of new modes of molecular regulation and new vesicle traffic pathways.
Topics: Computational Biology; Computer Graphics; Eukaryotic Cells; SNARE Proteins; Transport Vesicles
PubMed: 35092413
DOI: No ID Found -
Seminars in Cell & Developmental Biology Feb 2011Vesicle trafficking is a highly regulated process that transports proteins and other cargoes through eukaryotic cells while maintaining cellular organization and... (Review)
Review
Vesicle trafficking is a highly regulated process that transports proteins and other cargoes through eukaryotic cells while maintaining cellular organization and compartmental identity. In order for cargo to reach the correct destination, each step of trafficking must impart specificity. During vesicle formation, this is achieved by coat proteins, which selectively incorporate cargo into the nascent vesicle. Classically, vesicle coats are thought to dissociate shortly after budding. However, recent studies suggest that coat proteins can remain on the vesicle en route to their destination, imparting targeting specificity by physically and functionally interacting with Rab-regulated tethering systems. This review focuses on how interactions among Rab GTPases, tethering factors, SNARE proteins, and vesicle coats contribute to vesicle targeting, fusion, and coat dynamics.
Topics: Animals; Biological Transport; Coated Vesicles; Humans; Protein Binding; Protein Subunits; rab GTP-Binding Proteins
PubMed: 20643221
DOI: 10.1016/j.semcdb.2010.07.003