Abstract
The assembly of von Willebrand factor (VWF) into ordered helical tubules within endothelial Weibel–Palade bodies (WPBs) is required for the efficient deployment of the protein at sites of
vascular injury. VWF trafficking and storage are sensitive to cellular and environmental stresses that
are associated with heart disease and heart failure. Altered storage of VWF manifests as a change
in WPB morphology from a rod shape to a rounded shape and is associated with impaired VWF
deployment during secretion. In this study, we examined the morphology, ultrastructure, molecular
composition and kinetics of exocytosis of WPBs in cardiac microvascular endothelial cells isolated
from explanted hearts of patients with a common form of heart failure, dilated cardiomyopathy
(DCM; HCMECD), or from nominally healthy donors (controls; HCMECC). Using fluorescence
microscopy, WPBs in HCMECC (n = 3 donors) showed the typical rod-shaped morphology containing
VWF, P-selectin and tPA. In contrast, WPBs in primary cultures of HCMECD (n = 6 donors) were
predominantly rounded in shape and lacked tissue plasminogen activator (t-PA). Ultrastructural
analysis of HCMECD revealed a disordered arrangement of VWF tubules in nascent WPBs emerging
from the trans-Golgi network. HCMECD WPBs still recruited Rab27A, Rab3B, Myosin-Rab Interacting
Protein (MyRIP) and Synaptotagmin-like protein 4a (Slp4-a) and underwent regulated exocytosis
with kinetics similar to that seen in HCMECc. However, secreted extracellular VWF strings from
HCMECD were significantly shorter than for endothelial cells with rod-shaped WPBs, although VWF
platelet binding was similar. Our observations suggest that VWF trafficking, storage and haemostatic
potential are perturbed in HCMEC from DCM hearts.
vascular injury. VWF trafficking and storage are sensitive to cellular and environmental stresses that
are associated with heart disease and heart failure. Altered storage of VWF manifests as a change
in WPB morphology from a rod shape to a rounded shape and is associated with impaired VWF
deployment during secretion. In this study, we examined the morphology, ultrastructure, molecular
composition and kinetics of exocytosis of WPBs in cardiac microvascular endothelial cells isolated
from explanted hearts of patients with a common form of heart failure, dilated cardiomyopathy
(DCM; HCMECD), or from nominally healthy donors (controls; HCMECC). Using fluorescence
microscopy, WPBs in HCMECC (n = 3 donors) showed the typical rod-shaped morphology containing
VWF, P-selectin and tPA. In contrast, WPBs in primary cultures of HCMECD (n = 6 donors) were
predominantly rounded in shape and lacked tissue plasminogen activator (t-PA). Ultrastructural
analysis of HCMECD revealed a disordered arrangement of VWF tubules in nascent WPBs emerging
from the trans-Golgi network. HCMECD WPBs still recruited Rab27A, Rab3B, Myosin-Rab Interacting
Protein (MyRIP) and Synaptotagmin-like protein 4a (Slp4-a) and underwent regulated exocytosis
with kinetics similar to that seen in HCMECc. However, secreted extracellular VWF strings from
HCMECD were significantly shorter than for endothelial cells with rod-shaped WPBs, although VWF
platelet binding was similar. Our observations suggest that VWF trafficking, storage and haemostatic
potential are perturbed in HCMEC from DCM hearts.
| Original language | English |
|---|---|
| Article number | 4553 |
| Journal | International Journal of Molecular Sciences |
| Volume | 24 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - Mar 2023 |
Bibliographical note
Funding Information:TC was funded by the UK Medical Research Council under the program grant MC_PC_13053. P.B.R. and J.E.M. are supported by the Francis Crick Institute, which receives its core funding from Cancer Research UK (CC2106 (P.B.R), FC001178 (J.E.M), the Wellcome Trust (CC2106 (P.B.R), FC001119 (J.E.M)), and the UK Medical Research Council (CC2106 (P.B.R), FC001119 (J.E.M)). R.B. is funded by grants from the Landsteiner Stichting voor Bloedtransfusie Research (LSBR-1707 and LSBR-2005). M.L.R. was supported by the British Heart Foundation (RG/06/004). For the purpose of Open Access, the authors have applied a CC BY public copyright license to any Author Accepted Manuscript version arising from this submission.
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© 2023 by the authors.