Exosomes are lipid nanovesicles secreted from cells and found in all bodily fluids such as plasma, urine, and cerebrospinal fluid. Originally viewed as garbage disposal systems for cellular debris and proteins, they are now seen as playing a potentially important role in the development of real-time molecular diagnostics, drug delivery vehicles, and tools for biotech research.
GEN recently interviewed a number of specialists involved in exosome research to learn about the promise and capabilities of these fascinating nanovesicles.
Ms. Carnell: Exosomes appear to be ubiquitous in a broad range of prokaryotic and eukaryotic organisms, and for many years were regarded simply as cell debris. They are now known to be important in cellular communication and are believed to play a wide role in many physiological and pathological processes. Consequently they have the potential to be disease indicators, holding out the possibility of a role in early diagnostics, the focus of considerable R&D attention. They are also being investigated as drug delivery vehicles.
Dr. Clayton: The concept of exosomes challenges well-established dogma in cell biology, about cell-cell communication, and even perhaps the autonomy of a cell as the basic building blocks of living organisms. Countless studies now provide striking, highly compelling evidence for important functions of exosomes in driving disease processes, (cancer, neurodegeneration, cardiovascular disease, and many others).
Couple these with the idea of isolating exosomes from biofluids, as a source of multiple-molecular markers of disease, and we have a scenario where the field is now established as mainstream. Exosome research will be central to basic and translational biomedical science research in the future.
Dr. Henry: In addition to the potential for noninvasive diagnostics, exosomes and extracellular vesicles can also give us the timeliest information because they represent the state of the cell at that current moment. When we look at tissue, such as a tumor biopsy, we may actually be looking at years of history built up over time. With exosomes, we get a snapshot of what is happening in the body right now.
Exosomes also give us the ability to do liquid biopsies, which means that it’s easier for labs to get samples through blood, urine, saliva, various mucus membranes, etc. Easily obtained samples means faster processing times and potentially faster diagnoses.
Dr. Skog: The appeal of exosomes is their tremendous versatility. With the rise of targeted therapies, particularly for cancer, accurate and swift biomarker detection to match patients with the most tailored treatment is critical. Exosomes enable the detection of mutations, fusions, and splice variants, as well as RNA and protein profiling.
Additionally, exosome-based diagnostics have applications in many diseases beyond cancer, including neurological, endocrine, and cardiovascular disease, among others. In many cases, exosomes are part of the actual disease process, making them interesting from a biological standpoint, with clinical implications both for diagnostics as well as therapeutics.
Dr. Vlassov: Depending on the cell or tissue of origin, many different roles and functions have been attributed to exosomes: eradication of the obsolete molecules, facilitation of the immune response, antigen presentation, programmed cell death, angiogenesis, inflammation, coagulation, dissemination of oncogenes from tumor cells, and spread of pathogens such as prions and viruses between cells.
Importantly, exosomes deliver macromolecular messages (RNA and protein) that enable cell-to-cell communication and signaling. Interest in exosomes, from their function in the body to more practical applications, such as the use in diagnostics and therapeutics development, has grown exponentially in the last five years.