What are exosomes?
Exosomes are small spheroid vesicles (40-100nm) composed of a lipid bilayer with embedded proteins much like the cells plasma membrane. They are constitutively released by cells both in vitro and in vivo by the fusion of multi-vesicular bodies with the plasma membrane. They are released by a number of cell types such as hematopoietic cells, dendritic cells, tumor cells, adult and embryonic stem cells in the extracellular space. They have also been found in almost all body fluids including serum, saliva, milk, amniotic fluid and urine.
What are some of their functions?
Cells need to communicate with each other in both physiological and pathological conditions. Exosomes have emerged as important players in mediating cell-cell communication since they carry within them a cargo of proteins, functional mRNA and microRNA that can be transported to cells situated proximally or distally via movement through biological fluids. They can fuse with the target cell and deliver a load of bioactive molecules which can then modify the target cell’s behavior. They play important roles in many physiological processes like antigen presentation, tissue repair as well as pathological processes like progression of neurodegenrative diseases, cancer, spread of prions and viruses, and cardiovascular disease. Their role in diverse processes coupled with circulation in biological fluids makes them ideal diagnostic and therapeutic entities.
We are currently taking an integrated systems biology approach to investigate the role of exosomes in mediating target cell transcriptomics under pathological conditions.
We are developing novel technologies to visualize exosomes in vivo since our ability to image exosomes in vivo has been limited largely by a lack of available technology.
We are trying to characterize exosomes from novel sources to establish their role as a universal mechanism by which cells traffic material and communicate in both health and disease.