Maintenance of myocardial homeostasis requires a stable and harmonised contribution from various cell types. Myocardial infarction results in a sequence of repair mechanisms, including a complex coordinated cellular response, that must be appropriate to the injury severity for effective damage control and repair. Intercellular communication is integral to cellular coordination, especially in complex tissue contexts. Extracellular vesicles provide a mechanism for molecular transport across extracellular space, allowing signals to be propagated locally and systemically during homeostasis and critically in pathological scenarios. Capable of carrying a wide range of lipids, proteins and nucleic acids, EVs can convey potent ‘messages’ resulting in physiological changes in the recipient cell. EVs are found in most biofluid samples and have been extensively studied ex vivo and in vitro, but few assessments have been made regarding endogenously produced EVs in vivo, especially within vertebrate models. This project makes use of transgenic larval zebrafish as a vertebrate model system that delivers optical accessibility in combination with transgenic tractability, permitting subcellular in vivo live-imaging of endogenous EVs. Using a membrane-tethered fluorophore system EVs can be fluorescently labelled and tracked in vivo. This has allowed endothelial cell-derived EVs to be visualised in the peripheral circulation and cardiomyocyte-derived EVs to be observed in the pericardial fluid that surrounds the heart, revealing previously unseen in vivo distribution and behaviour. The fluorescent reporter also allows EVs to be extracted from whole larvae and assessed ex vivo; in this project EVs were counted via a modified flow cytometry setup, revealing subtle changes in EV numbers in response to cardiac injury. It was also demonstrated that EVs can be isolated via fluorescence activated cell sorting, which opens many opportunities for future work describing cell type specific EV cargo and how this may change during cardiac repair and regeneration.
|Date of Award||6 Nov 2018|
- The University of Bristol
|Supervisor||Beck J Richardson (Supervisor), Paul B Martin (Supervisor) & Costanza Emanueli (Supervisor)|