Exosomes are small membrane-enclosed delivery vehicles (40-150nm in diameter), which selectively package and transport molecules from host to target cells. Exosome-packaged molecules can be proteins, RNAs and non-coding RNAs such as microRNAs (miRNAs). MiRNAs are endogenous ‘master-regulators’ of gene expression and a single miRNA can control multiple different mRNAs, often found within similar biological pathways. The exosomal transfer of these molecules, particularly miRNAs, can therefore functionally alter the environment of target cells. Exosomes are paramount to the pathogenesis of a plethora of neurodegenerative diseases but their role in retinal degenerations remains largely unknown. At the Clear Vision Research Lab we study exosomes using several miRNA-centered approaches:
i) We are characterising the molecular cargo of retinal exosomes, in particular their miRNA signature, to understand the relevance of these in the establishment and development of retinal degenerations.
ii) Exosomes are known to be efficient at delivering their molecular contents, including miRNA, to recipient cells. To utilize this high delivery efficiency, we are developing ways to enrich retinal exosomes with specific miRNAs of therapeutic potential in an effort to deliver these directly into the degenerating retina.
iii) Exosome-packaged molecules have high diagnostic potential. Exosomes also have the capacity to travel from their organ of origin, such as the retina, via biofluids such as blood. We are working towards uncovering the signature imprinted on blood-derived exosomes with the goal of establishing a panel of exosome-based biomarkers of retinal degenerations. This will aid the development of an objective and precise diagnostic kit for retinal degenerations.