What is going on between defibrotide and endothelial cells? Snapshots reveal the
hot spots of their romance
#MMPMID26755708
Palomo M
; Mir E
; Rovira M
; Escolar G
; Carreras E
; Diaz-Ricart M
Blood
2016[Mar]; 127
(13
): 1719-27
PMID26755708
show ga
Defibrotide (DF) has received European Medicines Agency authorization to treat
sinusoidal obstruction syndrome, an early complication after hematopoietic cell
transplantation. DF has a recognized role as an endothelial protective agent,
although its precise mechanism of action remains to be elucidated. The aim of the
present study was to investigate the interaction of DF with endothelial cells
(ECs). A human hepatic EC line was exposed to different DF concentrations,
previously labeled. Using inhibitory assays and flow cytometry techniques along
with confocal microscopy, we explored: DF-EC interaction, endocytic pathways, and
internalization kinetics. Moreover, we evaluated the potential role of adenosine
receptors in DF-EC interaction and if DF effects on endothelium were dependent of
its internalization. Confocal microscopy showed interaction of DF with EC
membranes followed by internalization, though DF did not reach the cell nucleus
even after 24 hours. Flow cytometry revealed concentration, temperature, and time
dependent uptake of DF in 2 EC models but not in other cell types. Moreover,
inhibitory assays indicated that entrance of DF into ECs occurs primarily through
macropinocytosis. Our experimental approach did not show any evidence of the
involvement of adenosine receptors in DF-EC interaction. The antiinflammatory and
antioxidant properties of DF seem to be caused by the interaction of the drug
with the cell membrane. Our findings contribute to a better understanding of the
precise mechanisms of action of DF as a therapeutic and potential preventive
agent on the endothelial damage underlying different pathologic situations.
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