Our cells communicate with each other by releasing and taking up small packages of cellular material, referred to as exosomes. These extracellular vesicles have many important functions in healthy individuals, for example by aiding the immune system or maintenance of neurons in the brain. In recent years it has become clear that many pathogens, including parasites, viruses and even certain bacteria, modulate exosome-mediated communication in the host organism. These pathogen-modified exosomes often act to promote the survival and replication of the pathogen in infected individuals.
Although the role of exosomal communication during microbial infection becomes increasingly clear, our knowledge of the cellular mechanisms that mediate and control pathogenic exosome release is limited. One of the reasons for this is the small size of exosomes (± 100 nm), which makes it difficult to detect their secretion using normal light microscopy. To overcome this problem, AIMMS researcher Bebelman has developed a reporter protein that gives bright flashes of fluorescence every time a cell releases exosomes. This allows him to follow exosome secretion in real-time in single cells.
In future experiments Bebelman can use this system to decipher the mechanisms by which bacterial, parasitic or viral infections modulate host exosome release. Ultimately Bebelman aims to use this knowledge to selectively inhibit pathogen-induced exosome release from infected cells, while keeping normal exosomal communication by healthy cells intact.
Figure: Projection of exosome release events (yellow spots) in non-infected human cells (blue) over a time-course of 3 minutes.