Exosomes: Definition, Function and Use in Therapy – Technology Networks
Posted: April 29, 2020 at 5:41 pm
What are exosomes?
Exosomes are a class of cell-derived extracellular vesicles of endosomal origin, and are typically 30-150 nm in diameter the smallest type of extracellular vesicle.1 Enveloped by a lipid bilayer, exosomes are released into the extracellular environment containing a complex cargo of contents derived from the original cell, including proteins, lipids, mRNA, miRNA and DNA.2 Exosomes are defined by how they are formed through the fusion and exocytosis of multivesicular bodies into the extracellular space.
Multivesicular bodies* are unique organelles in the endocytic pathway that function as intermediates between early and late endosomes.3 The main function of multivesicular bodies is to separate components that will be recycled elsewhere from those that will be degraded by lysosomes.4 The vesicles that accumulate within multivesicular bodies are categorized as intraluminal vesicles while inside the cytoplasm and exosomes when released from the cell.
*Confusingly, there is inconsistency in the literature; while some sources differentiate multivesicular bodies from late endosomes, others use the two interchangeably.
Exosomes are of general interest for their role in cell biology, and for their potential therapeutic and diagnostic applications. It was originally thought that exosomes were simply cellular waste products, however their function is now known to extend beyond waste removal. Exosomes represent a novel mode of cell communication and contribute to a spectrum of biological processes in health and disease.2One of the main mechanisms by which exosomes are thought to exert their effects is via the transfer of exosome-associated RNA to recipient cells, where they influence protein machinery. There is growing evidence to support this, such as the identification of intact and functional exosomal RNA in recipient cells and certain RNA-binding proteins have been identified as likely players in the transfer of RNA to target cells.5,6 MicroRNAs and long noncoding RNAs are shuttled by exosomes and alter gene expression while proteins (e.g. heat shock proteins, cytoskeletal proteins, adhesion molecules, membrane transporter and fusion proteins) can directly affect target cells.7,8Exosomes have been described as messengers of both health and disease. While they are essential for normal physiological conditions, they also act to potentiate cellular stress and damage under disease states.2
Multivesicular bodies are a specialized subset of endosomes that contain membrane-bound intraluminal vesicles. Intraluminal vesicles are essentially the precursors of exosomes, and form by budding into the lumen of the multivesicular body. Most intraluminal vesicles fuse with lysosomes for subsequent degradation, while others are released into the extracellular space.9,10 The intraluminal vesicles that are secreted into the extracellular space become exosomes. This release occurs when the multivesicular body fuses with the plasma membrane.
The formation and degradation of exosomes.
This is an active area of research and it is not yet known how exosome release is regulated. However, recent advances in imaging protocols may allow exosome release events to be visualized at high spatiotemporal resolution.11
Exosomes have been implicated in a diverse range of conditions including neurodegenerative diseases, cancer, liver disease and heart failure. Like other microvesicles, the function of exosomes likely depends on the cargo they carry, which is dependent on the cell type in which they were produced.12 Researchers have studied exosomes in disease through a range of approaches, including:
In cancer, exosomes have multiple roles in metastatic spread, drug resistance and angiogenesis. Specifically, exosomes can alter the extracellular matrix to create space for migrating tumor cells.13,14 Several studies also indicate that exosomes can increase the migration, invasion and secretion of cancer cells by influencing genes involved with tumor suppression and extracellular matrix degradation.15,16Through general cell crosstalk, exosomal miRNA and lncRNA affect the progression of lung diseases including chronic obstructive pulmonary disease (COPD), asthma, tuberculosis and interstitial lung diseases. Stressors such as oxidant exposure can influence the secretion and cargo of exosomes, which in turn affect inflammatory reactions.17 Altered exosomal profiles in diseased states also imply a role for exosomes in many other conditions such as in neurodegenerative diseases and mental disorders.18,19Cells exposed to bacteria release exosomes which act like decoys to toxins, suggesting a protective effect during infection.20 In neuronal circuit development, and in many other systems, exosomal signaling is likely to be a sum of overlapping and sometimes opposing signaling networks.21
Exosomes can function as potential biomarkers, as their contents are molecular signatures of their originating cells. Due to the lipid bilayer, exosomal contents are relatively stable and protected against external proteases and other enzymes, making them attractive diagnostic tools. There are increasing reports that profiles of exosomal miRNA and lncRNA differ in patients with certain pathologies, compared with those of healthy people.17 Consequently, exosome-based diagnostic tests are being pursued for the early detection of cancer, diabetes and other diseases.22,23Many exosomal proteins, nucleic acids and lipids are being explored as potential clinically relevant biomarkers.24 Phosphorylation proteins are promising biomarkers that can be separated from exosomal samples even after five years in the freezer25, while exosomal microRNA also appears to be highly stable.26 Exosomes are also highly accessible as they are present in a wide array of biofluids (including blood, urine, saliva, tears, ascites, semen, colostrum, breast milk, amniotic fluid and cerebrospinal fluid), creating many opportunities for liquid biopsies.
Exosomes are being pursued for use in an array of potential therapeutic applications. While externally modified vesicles suffer from toxicity and rapid clearance, membranes of naturally occurring vesicles are better tolerated, offering low immunogenicity and a high resilience in extracellular fluid.27 These naturally-equipped nanovesicles could be therapeutically targeted or engineered as drug delivery systems.
Exosomes bear surface molecules that allow them to be targeted to recipient cells, where they deliver their payload. This could be used to target them to diseased tissues or organs.27 Exosomes may cross the blood-brain barrier, at least under certain conditions28 and could be used to deliver an array of therapies including small molecules, RNA therapies, proteins, viral gene therapy and CRISPR gene-editing.
Different approaches to creating drug-loaded exosomes include27:
Exosomes hold huge potential as a way to complement chimeric antigen receptor T (CAR-T) cells in attacking cancer cells. CAR exosomes, which are released from CAR-T cells, carry CAR on their surface and express a high level of cytotoxic molecules and inhibit tumor growth.29 Cancer cell-derived exosomes carrying associated antigens have also been shown to recruit an antitumor immune response.30
The purification of exosomes is a key challenge in the development of translational tools. Exosomes must be differentiated from other distinct populations of extracellular vesicles, such as microvesicles (which shed from the plasma membrane, also referred to as ectosomes or shedding vesicles) and apoptotic bodies.31 Although ultracentrifugation is regarded as the gold standard for exosome isolation, it has many disadvantages and alternative methods for exosome isolation are currently being sought. Exosome isolation is an active area of research (see Table 1) and many research groups are seeking ways to overcome the disadvantages listed below, while navigating the relevant regulatory hurdles along the way.
Produces a low yield and low purity of the isolated exosomes as other types of extracellular vesicles have similar sedimentation properties.
Low efficiency as it is labor-intensive, time-consuming and requires a large amount of sample. specialized equipment. High centrifugal force can damage exosome integrity
Originally posted here:
Exosomes: Definition, Function and Use in Therapy - Technology Networks
- Gene Therapy Could Prevent Blindness [Last Updated On: June 10th, 2010] [Originally Added On: June 10th, 2010]
- Gene Brodland Sits with Cambridge Who's Who in a Revealing Interview [Last Updated On: June 16th, 2010] [Originally Added On: June 16th, 2010]
- Researchers Make Colon Cancer Breakthrough [Last Updated On: July 20th, 2010] [Originally Added On: July 20th, 2010]
- Pro abortion- Antiabortion myth8 - Fly to India for safe abortion! [Last Updated On: October 16th, 2010] [Originally Added On: October 16th, 2010]
- New Fertility Test / Whooping Cough Alert / Gene Therapy for Depression [Last Updated On: October 21st, 2010] [Originally Added On: October 21st, 2010]
- Alzheimer's Breakthrough? [Last Updated On: October 23rd, 2010] [Originally Added On: October 23rd, 2010]
- Audio Genetics Lab - Native Flute - MP3Tera Forums [Last Updated On: December 8th, 2010] [Originally Added On: December 8th, 2010]
- Gene Therapy - Cortical Studios [Last Updated On: May 8th, 2011] [Originally Added On: May 8th, 2011]
- There Shall Be Physicians for the Spirit: USC Institute for Genetic Medicine Art Gallery [Last Updated On: May 8th, 2011] [Originally Added On: May 8th, 2011]
- IRRI: Rice genetic diversity and discovery [Last Updated On: May 8th, 2011] [Originally Added On: May 8th, 2011]
- Research Symposium: Mork Depart - 2006 - Video 1 [Last Updated On: May 8th, 2011] [Originally Added On: May 8th, 2011]
- Mendelian Genetics [Last Updated On: May 8th, 2011] [Originally Added On: May 8th, 2011]
- Ayurveda [Last Updated On: May 8th, 2011] [Originally Added On: May 8th, 2011]
- Drs. Kaspar and MacKenzie discuss the promise and path forward for SMA Gene Therapy [Last Updated On: May 8th, 2011] [Originally Added On: May 8th, 2011]
- 3. Genetic Engineering [Last Updated On: May 8th, 2011] [Originally Added On: May 8th, 2011]
- Prof. Martinez Cruzado Lecture Part 3 "Amerindian Gene Study In Puerto Rico" [Last Updated On: May 8th, 2011] [Originally Added On: May 8th, 2011]
- Gene Therapy Research Makes Nationwide Children's Worthy of Wellstone Center [Last Updated On: May 8th, 2011] [Originally Added On: May 8th, 2011]
- Gene Therapy Example [Last Updated On: May 9th, 2011] [Originally Added On: May 9th, 2011]
- Sweet Tooth Gene [Last Updated On: May 9th, 2011] [Originally Added On: May 9th, 2011]
- OHSU's video of new gene therapy method developed at the Oregon National Primate Research Center [Last Updated On: May 9th, 2011] [Originally Added On: May 9th, 2011]
- Gregor Mendel's Punnett Squares [Last Updated On: May 9th, 2011] [Originally Added On: May 9th, 2011]
- Ethical Concerns With Genetic Engineering [Last Updated On: May 9th, 2011] [Originally Added On: May 9th, 2011]
- Dr. Laura Niklason on the importance of her AFAR grants for telomerase gene therapy research [Last Updated On: May 9th, 2011] [Originally Added On: May 9th, 2011]
- What is the future of genetic medicine? [Last Updated On: May 9th, 2011] [Originally Added On: May 9th, 2011]
- Prof. Martinez Cruzado Lecture Part 2 "Amerindian Gene Study In Puerto Rico" [Last Updated On: May 9th, 2011] [Originally Added On: May 9th, 2011]
- Jewish DNA - Genetic Research and The Origins of the Jewish People [Last Updated On: May 9th, 2011] [Originally Added On: May 9th, 2011]
- Future of genetic engineering - by Futurist Dr Patrick Dixon. Genetic mutations and genetic disorders. Gene science by conference keynote speaker [Last Updated On: May 11th, 2011] [Originally Added On: May 11th, 2011]
- annstewart82's Genetic Medicine and God [Last Updated On: May 13th, 2011] [Originally Added On: May 13th, 2011]
- Genetic research could unlock breeding seasons in sheep [Last Updated On: May 13th, 2011] [Originally Added On: May 13th, 2011]
- Genetics 101 Part 1: What are genes? [Last Updated On: May 13th, 2011] [Originally Added On: May 13th, 2011]
- Molecular and Cellular Foundations of Medicine, 1 of 2 [Last Updated On: May 13th, 2011] [Originally Added On: May 13th, 2011]
- Dan Arking of Johns Hopkins Medicine [Last Updated On: May 17th, 2011] [Originally Added On: May 17th, 2011]
- Genetics : How Is Gene Therapy Done? [Last Updated On: May 19th, 2011] [Originally Added On: May 19th, 2011]
- Gene Therapy Shows Promise for Blindness [Last Updated On: May 19th, 2011] [Originally Added On: May 19th, 2011]
- Tomato suicide gene therapy [Last Updated On: May 19th, 2011] [Originally Added On: May 19th, 2011]
- Cancer Alternative Treatment - Gene Therapy for Cancer a Report from Channel 4 News [Last Updated On: May 19th, 2011] [Originally Added On: May 19th, 2011]
- Muscular Dystrophy Gene Therapy: ScienCentral News Video [Last Updated On: May 19th, 2011] [Originally Added On: May 19th, 2011]
- Sickle Cell Anemia -- Hope from Gene Therapy [Last Updated On: May 19th, 2011] [Originally Added On: May 19th, 2011]
- Challenges of gene therapy [Last Updated On: May 19th, 2011] [Originally Added On: May 19th, 2011]
- Pain Gene Therapy [Last Updated On: May 19th, 2011] [Originally Added On: May 19th, 2011]
- Gene therapy success 'reverses' blindness [Last Updated On: May 19th, 2011] [Originally Added On: May 19th, 2011]
- DNA Gene Therapy [Last Updated On: May 19th, 2011] [Originally Added On: May 19th, 2011]
- The Neural Circuitry of Perception [Last Updated On: May 19th, 2011] [Originally Added On: May 19th, 2011]
- Resetting Metabolism- Nuclear Receptors and AMPK: A Lecture by Ronald Evans, PhD [Last Updated On: May 19th, 2011] [Originally Added On: May 19th, 2011]
- Islands at Risk (Part 2) - Genetic Engineering in Hawai'i [Last Updated On: May 19th, 2011] [Originally Added On: May 19th, 2011]
- Gene Therapy journal videocast from ASGCT 2011 Xiao Xiao on gene therapy for muscular dystrophy [Last Updated On: May 20th, 2011] [Originally Added On: May 20th, 2011]
- HYBRID HUMANS-Hair Follicle Gene Therapy [Last Updated On: May 20th, 2011] [Originally Added On: May 20th, 2011]
- Genetics 101 Part 4: What is phenotype? [Last Updated On: May 20th, 2011] [Originally Added On: May 20th, 2011]
- Lloyd Pye - Ancient Genetic Engineering [Last Updated On: May 20th, 2011] [Originally Added On: May 20th, 2011]
- Study Designs: Genetic Association Studies [Last Updated On: May 20th, 2011] [Originally Added On: May 20th, 2011]
- Gene Therapy for Genetic Disease: The Long and Winding Road [Last Updated On: May 20th, 2011] [Originally Added On: May 20th, 2011]
- Introduction to Population Genetics [Last Updated On: May 20th, 2011] [Originally Added On: May 20th, 2011]
- Islands at Risk (Part 1) - Genetic Engineering in Hawai'i [Last Updated On: May 20th, 2011] [Originally Added On: May 20th, 2011]
- Genetics Based Research on Treatment-Resistant Epilepsy [Last Updated On: May 20th, 2011] [Originally Added On: May 20th, 2011]
- Science in Action: Gene Therapy for Color Blindness [Last Updated On: May 21st, 2011] [Originally Added On: May 21st, 2011]
- Gregg Semenza of Johns Hopkins Medicine on HIF 1 [Last Updated On: May 21st, 2011] [Originally Added On: May 21st, 2011]
- The Sleepiness Gene [Last Updated On: May 21st, 2011] [Originally Added On: May 21st, 2011]
- Blind Gene Therapy [Last Updated On: May 21st, 2011] [Originally Added On: May 21st, 2011]
- Richard Dawkins and Dr Yan on genetic ancestry (extended version) - Bang Goes the Theory - BBC One [Last Updated On: May 22nd, 2011] [Originally Added On: May 22nd, 2011]
- Joshua Mendell of Johns Hopkins Medicine [Last Updated On: May 22nd, 2011] [Originally Added On: May 22nd, 2011]
- Genetic/Genomic Faculty Champion Initiative (PM session) [Last Updated On: May 22nd, 2011] [Originally Added On: May 22nd, 2011]
- euronews science - Epigenetics [Last Updated On: May 22nd, 2011] [Originally Added On: May 22nd, 2011]
- The Genetic Age, Panel 1 [Last Updated On: May 22nd, 2011] [Originally Added On: May 22nd, 2011]
- Biobanking and Bioethics: When Genetics Research Hits the Courts [Last Updated On: May 22nd, 2011] [Originally Added On: May 22nd, 2011]
- Gene Therapy journal videocast from ASGCT 2011 Darren Wolfe on gene therapy for pain.m4v [Last Updated On: May 23rd, 2011] [Originally Added On: May 23rd, 2011]
- Genetics 101 Part 3: Where do your genes come from? [Last Updated On: May 23rd, 2011] [Originally Added On: May 23rd, 2011]
- ASHG 2010 Mtg.: "Complex Disease Genetics Research in Populations" (Dr. Carlos Bustamente) [Last Updated On: May 23rd, 2011] [Originally Added On: May 23rd, 2011]
- Public Talk - Prof Leonard Seymour, Oxford [Last Updated On: May 23rd, 2011] [Originally Added On: May 23rd, 2011]
- A New Era in Medicine: Genetics [Last Updated On: May 23rd, 2011] [Originally Added On: May 23rd, 2011]
- Genetic Engineering Animation [Last Updated On: May 23rd, 2011] [Originally Added On: May 23rd, 2011]
- Linda Brzustowicz - Genetic Causes of Schizophrenia [Last Updated On: May 23rd, 2011] [Originally Added On: May 23rd, 2011]
- Hadassah Gene Therapy Center [Last Updated On: May 23rd, 2011] [Originally Added On: May 23rd, 2011]
- Gene Therapy journal videocast from ASGCT 2011 Robin Ali on gene therapy for retinal disease [Last Updated On: May 23rd, 2011] [Originally Added On: May 23rd, 2011]
- UF cardiologists study gene-modified stem cells to help Dobermans with common heart condition [Last Updated On: May 23rd, 2011] [Originally Added On: May 23rd, 2011]
- Akhilesh Pandey of Johns Hopkins Medicine [Last Updated On: May 23rd, 2011] [Originally Added On: May 23rd, 2011]
- China's Cancer Drug - China [Last Updated On: May 23rd, 2011] [Originally Added On: May 23rd, 2011]
- Genetic Therapy Restored Boy's Sight [Last Updated On: May 24th, 2011] [Originally Added On: May 24th, 2011]
- Molecular and Cellular Foundations of Medicine Class, 2 of 2 [Last Updated On: May 24th, 2011] [Originally Added On: May 24th, 2011]
- Talking Research - Professor George Ebers - Vitamin D and genetics in MS [Last Updated On: May 24th, 2011] [Originally Added On: May 24th, 2011]
- Designing Humanity - Genetic Engineering [Last Updated On: May 30th, 2011] [Originally Added On: May 30th, 2011]