%0 Journal Article
%@ 1538-7836
%A McCormack, JJ
%A Harrison-Lavoie, K
%A Cutler, DF
%D 2020
%F discovery:10082089
%J Journal of Thrombosis and Haemostasis
%K Endothelial Cells, Exocytosis, Organelle Size, Weibel-Palade Bodies, von Willebrand Factor
%N 1
%P 243-254
%T Human endothelial cells size-select their secretory granules for exocytosis to modulate their functional output
%U https://discovery.ucl.ac.uk/id/eprint/10082089/
%V 18
%X BACKGROUND: The secretory granules of endothelial cells, Weibel-Palade bodies, are released in response to numerous extracellular signals. Their cargo is critical to many vascular functions including haemostasis and inflammation. This presents a fundamental problem; how can these cells initiate tailor-made responses from the release of a single type of organelle, each with similar cargo? Each cell contains Weibel-Palade bodies in a wide range of sizes, and we have shown that experimentally-shortening these organelles disproportionately reduces their ability to initiate haemostasis in vitro, leaving leukocyte recruitment unaffected. Could the production of this range of sizes underpin differential responses? OBJECTIVES: To determine whether different agonists drive the exocytosis of different sizes of Weibel-Palade bodies. METHODS: We used a high-throughput automated unbiased imaging workflow to analyse the sizes of Weibel-Palade bodies within HUVECs before and after agonist activation to determine changes in organelle size distributions. RESULTS: We found that a subset of agonists differentially evoke the release of the longest, most pro-haemostatic organelles. Inhibiting the release of these longest organelles by just 15% gives a fall of 60% in an assay of secreted VWF function. CONCLUSIONS: The size-selection of granules for exocytosis represents a novel layer of control, allowing endothelial cells to provide diverse responses to different signals via the release of a single type of organelle.
%Z This version is the author accepted manuscript . For information on re-use, please refer to the publisher’s terms and conditions.