In cell biology, a vesicle is a structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a lipid bilayer. Vesicles form naturally during the processes of secretion (exocytosis), uptake (endocytosis), and the transport of materials within the plasma membrane. Alternatively, they may be prepared artificially, in which case they are called liposomes. If there is only one phospholipid bilayer, the vesicles are called unilamellar liposomes; otherwise they are called multilamellar liposomes. The membrane enclosing the vesicle is also a lamellar phase, similar to that of the plasma membrane, and intracellular vesicles can fuse with the plasma membrane to release their contents outside the cell. Vesicles can also fuse with other organelles within the cell. A vesicle released from the cell is known as an extracellular vesicle.
Microparticles are particles between 0.1 and 100 μm in size. Commercially available microparticles are available in a wide variety of materials, including ceramics, glass, polymers, and metals. Microparticles encountered in daily life include pollen, sand, dust, flour, and powdered sugar.
Exosomes, ranging in size from 30 to 150 nanometers, are membrane-bound extracellular vesicles (EVs) that are produced in the endosomal compartment of most eukaryotic cells. In multicellular organisms, exosomes and other EVs are found in biological fluids including saliva, blood, urine and cerebrospinal fluid. EVs have specialized functions in physiological processes, from coagulation and waste management to intercellular communication.
An adrenal tumor or adrenal mass is any benign or malignant neoplasms of the adrenal gland, several of which are notable for their tendency to overproduce endocrine hormones. Adrenal cancer is the presence of malignant adrenal tumors, and includes neuroblastoma, adrenocortical carcinoma and some adrenal pheochromocytomas. Most adrenal pheochromocytomas and all adrenocortical adenomas are benign tumors, which do not metastasize or invade nearby tissues, but may cause significant health problems by unbalancing hormones.
Microvesicles are a type of extracellular vesicle (EV) that are released from the cell membrane. In multicellular organisms, microvesicles and other EVs are found both in tissues and in many types of body fluids. Delimited by a phospholipid bilayer, microvesicles can be as small as the smallest EVs or as large as 1000 nm. They are considered to be larger, on average, than intracellularly-generated EVs known as exosomes. Microvesicles play a role in intercellular communication and can transport molecules such as mRNA, miRNA, and proteins between cells.
CD63 antigen is a protein that, in humans, is encoded by the CD63 gene. CD63 is mainly associated with membranes of intracellular vesicles, although cell surface expression may be induced.
ExoCarta is a manually curated database of exosomal proteins, RNA and lipids.
Jan Lötvall is a Swedish clinical allergist and scientist working on translational research primarily in the field of asthma. He is the former director of the Krefting Research Centre at the University of Gothenburg and is the Chief Scientific Officer of ExoCoBio.
Izon Science Limited is a nanotechnology company that develops and sells nano-scale particle analysis and isolation tools. Their main instruments are based on principles of size exclusion chromatography and tunable resistive pulse sensing. Izon’s size-exclusion chromatography columns and related solutions are also used by diagnostics companies focused on developing extracellular vesicle biomarkers.
Extracellular RNA (exRNA) describes RNA species present outside of the cells in which they were transcribed. Carried within extracellular vesicles, lipoproteins, and protein complexes, exRNAs are protected from ubiquitous RNA-degrading enzymes. exRNAs may be found in the environment or, in multicellular organisms, within the tissues or biological fluids such as venous blood, saliva, breast milk, urine, semen, menstrual blood, and vaginal fluid. Although their biological function is not fully understood, exRNAs have been proposed to play a role in a variety of biological processes including syntrophy, intercellular communication, and cell regulation. The United States National Institutes of Health (NIH) published in 2012 a set of Requests for Applications (RFAs) for investigating extracellular RNA biology. Funded by the NIH Common Fund, the resulting program was collectively known as the Extracellular RNA Communication Consortium (ERCC). The ERCC was renewed for a second phase in 2019.
Tunable resistive pulse sensing (TRPS) is a single-particle technique used to measure the size, concentration and zeta potential of particles as they pass through a size-tunable nanopore.
Membrane vesicle trafficking in eukaryotic animal cells involves movement of biochemical signal molecules from synthesis-and-packaging locations in the Golgi body to specific release locations on the inside of the plasma membrane of the secretory cell. It takes place in the form of Golgi membrane-bound micro-sized vesicles, termed membrane vesicles (MVs).
The International Society for Extracellular Vesicles (ISEV) is an international scientific organization that focuses on the study of extracellular vesicles (EVs). These membrane-bound particles are released from all known cells and include exosomes, ectosomes, exophers, oncosomes, and more. Established in 2011, the society is a nonprofit organization. It is governed by an executive committee. The current president is Buzás Edit. Previous presidents were Clotilde Théry (2018-2022), Andrew Hill (2016-2018) and founding president Jan Lötvall (2011-2016). The society's journals are the Journal of Extracellular Vesicles and the Journal of Extracellular Biology. ISEV also publishes the international consensus guidelines for EV studies, the "Minimal information for studies of EVs" (MISEV).
Extracellular vesicles (EVs) are lipid bilayer-delimited particles that are naturally released from almost all types of cells but, unlike a cell, cannot replicate. EVs range in diameter from near the size of the smallest physically possible unilamellar liposome to as large as 10 microns or more, although the vast majority of EVs are smaller than 200 nm. EVs can be divided according to size and synthesis route into exosomes, microvesicles and apoptotic bodies. The composition of EVs varies depending on their parent cells, encompassing proteins, lipids, nucleic acids, metabolites, and even organelles. Most cells that have been studied to date are thought to release EVs, including some archaeal, bacterial, fungal, and plant cells that are surrounded by cell walls. A wide variety of EV subtypes have been proposed, defined variously by size, biogenesis pathway, cargo, cellular source, and function, leading to a historically heterogenous nomenclature including terms like exosomes and ectosomes.
The stem cell secretome is a collective term for the paracrine soluble factors produced by stem cells and utilized for their inter-cell communication. In addition to inter-cell communication, the paracrine factors are also responsible for tissue development, homeostasis and (re-)generation. The stem cell secretome consists of extracellular vesicles, specifically exosomes, microvesicles, membrane particles, peptides and small proteins (cytokines). The paracrine activity of stem cells, i.e. the stem cell secretome, has been found to be the predominant mechanism by which stem cell-based therapies mediate their effects in degenerative, auto-immune and/or inflammatory diseases. Though not only stem cells possess a secretome which influences their cellular environment, their secretome currently appears to be the most relevant for therapeutic use.
Clotilde Théry is a professor and INSERM director of research (DR2) at Institut Curie in Paris, France. She is president of the International Society for Extracellular Vesicles (ISEV), where she previously served as founding secretary general and as editor-in-chief of the Journal of Extracellular Vesicles. She is team leader of the group "Extracellular Vesicles, Immune Responses and Cancer" within the INSERM Unit 932 on "Immunity and Cancer." Théry researches extracellular vesicles that are released by immune and tumor cells, including exosomes that originate in the multivesicular body.
Kenneth W. Witwer is an associate professor of molecular and comparative pathobiology and neurology at the Johns Hopkins University School of Medicine in Baltimore, Maryland, United States. As nominated President-Elect of the International Society for Extracellular Vesicles (ISEV), Witwer previously served as Secretary General and Executive Chair of Science and Meetings of the society. His laboratory studies extracellular vesicles (EVs), noncoding and extracellular RNA (exRNA), and enveloped viruses, including HIV and SARS-CoV-2. Witwer is the managing editor of the journal Cytotherapy and a member of the Richman Family Precision Medicine Center of Excellence in Alzheimer's Disease. He has advised the US Environmental Protection Agency and the US National Institutes of Health and is an associate editor of the Journal of Extracellular Vesicles.
Exophers are a type of membrane-bound extracellular vesicle (EV) that are released by budding out of cells into the extracellular space. Exophers can be released by neurons and muscle in the nematode Caenorhabditis elegans and also from murine cardiomyocytes. Exophers are notable for their large size, averaging approximately four microns in diameter, and they are able to expel whole organelles, such as mitochondria and lysosomes as cargo. An exopher can initially remain attached to the cell that produced it by a membranous filament that resembles a tunneling nanotube. Exophers share similarities with large oncosomes, but they differ in that they are produced by physiologically normal cells instead of aberrant cells associated with tumors.
Exosomes are small vesicles secreted by cells that play a crucial role in intercellular communication. They contain a variety of biomolecules, including proteins, nucleic acids and lipids, which can be transferred between cells to modulate cellular processes. Exosomes have been increasingly acknowledged as promising therapeutic tool and delivery platforms due to unique biological properties.
- Biocompatibility: Exosomes are naturally occurring particles in body, which makes them highly biocompatible and less likely to activate immune response.
- Targeting ability: Exosomes are assembled to express specific proteins or peptides, allowing them to target specific cells or tissues.
- Natural cargo carries: Exosomes can naturally transport a variety of biomolecules, including proteins, RNA and DNA, which can be used for therapeutic purposes.
Stefano Pluchino is Professor of Regenerative Neuroimmunology, within the Department of Clinical Neurosciences, at the University of Cambridge. His research studies whether the accumulation of neurological disability observed in patients with chronic inflammatory neurological conditions can be slowed down using next generation molecular therapies. The overarching aim is to understand the basic mechanisms that allow exogenously delivered stem cells, gene therapy vectors and/or exosomes to create an environment that preserves damaged axons or prevents neurons from dying. Such mechanisms are being harnessed and used to modulate disease states to repair and/or regenerate critical components of the nervous system.
