In vivo characterisation of endogenous cardiovascular extracellular vesicles in larval and adult zebrafish

Abstract

Ischaemic cardiac injury results in a complex coordinated cellular response that enables effective damage control and recovery. Intercellular communication is integral to the coordination of these repair responses in complex tissue contexts. Extracellular vesicles (EVs) facilitate molecular transport across extracellular space, allowing local and systemic signaling during homeostasis and in disease. Extensive in vitro studies have described the biogenesis, cargos and functional roles of EV populations but the characterisation of endogenously produced EVs in vivo is still in its infancy. Here we use larval and adult transgenic zebrafish to characterize endogenous cardiovascular EVs. Using a membranetethered fluorophore reporter system, cell-type specific EVs can be tracked in vivo by high spatiotemporal resolution light sheet imaging and modified flow cytometry methods allows these EVs to be extracted and assessed ex vivo. Importantly, we show that ischaemic cardiac injury models dynamically alter EV production during repair.

Zebrafish cardiac regeneration—looking beyond cardiomyocytes to a complex microenvironment

“…Despite this mounting evidence showing the importance of EVs, what we know thus far has been largely derived from in vitro studies (Van Niel et al 2018 ); however, novel methods are being developed to address the complexity and heterogeneity of endogenous EVs. Our laboratory has recently developed one such tool, combining the in vivo nature of the zebrafish model with a cell–membrane tagged fluorophore approach to facilitate future investigations of endogenous cell-type-specific EV populations (Scott et al 2019 ). This approach coupled with the cardiac cryoinjury model demonstrates dynamic changes in EV production post-injury and has potential to unlock the role of EVs in cell communication during repair and regeneration.…”