The shear stress-induced transcription factor KLF2 affects dynamics and angiopoietin-2 content of Weibel-Palade bodies.
BACKGROUND
The shear-stress induced transcription factor KLF2 has been shown to induce an atheroprotective phenotype in endothelial cells (EC) that are exposed to prolonged laminar shear. In this study we characterized the effect of the shear stress-induced transcription factor KLF2 on regulation and composition of Weibel-Palade bodies (WPBs) using peripheral blood derived ECs.


RESULTS
Lentiviral expression of KLF2 resulted in a 4.5 fold increase in the number of WPBs per cell when compared to mock-transduced endothelial cells. Unexpectedly, the average length of WPBs was significantly reduced: in mock-transduced endothelial cells WPBs had an average length of 1.7 µm versus 1.3 µm in KLF2 expressing cells. Expression of KLF2 abolished the perinuclear clustering of WPBs observed following stimulation with cAMP-raising agonists such as epinephrine. Immunocytochemistry revealed that WPBs of KLF2 expressing ECs were positive for IL-6 and IL-8 (after their upregulation with IL-1β) but lacked angiopoietin-2 (Ang2), a regular component of WPBs. Stimulus-induced secretion of Ang2 in KLF2 expressing ECs was greatly reduced and IL-8 secretion was significantly lower.


CONCLUSIONS
These data suggest that KLF2 expression leads to a change in size and composition of the regulated secretory compartment of endothelial cells and alters its response to physiological stimuli.
Department of Plasma Proteins, Sanquin-AMC Landsteiner Laboratory, University of Amsterdam, Amsterdam, The Netherlands.
Ellen L
EL
van Agtmaal
Ruben
R
Bierings
Bieuwke S
BS
Dragt
Thomas A
TA
Leyen
Mar
M
Fernandez-Borja
Anton J G
AJ
Horrevoets
Jan
J
Voorberg
D042702:Angiopoietin-2 / Q000096:biosynthesis*; D002478:Cells, Cultured; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D042783:Endothelial Cells; D005786:Gene Expression Regulation; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D033081:Shear Strength; D013312:Stress, Physiological; D020302:Weibel-Palade Bodies / Q000235:genetics / Q000378:metabolism*
C586513:ANGPT2 protein, human; D042702:Angiopoietin-2; D016207:Cytokines; C096161:KLF2 protein, human; D051741:Kruppel-Like Transcription Factors