TY - JOUR
T1 - Endothelial microparticle uptake in target cells is annexin I/phosphatidylserine receptor dependent and prevents apoptosis
AU - Jansen, Felix
AU - Yang, Xiaoyan
AU - Hoyer, Friedrich Felix
AU - Paul, Kathrin
AU - Heiermann, Nadine
AU - Becher, Marc Ulrich
AU - Abu Hussein, Nebal
AU - Kebschull, Moritz
AU - Bedorf, Jörg
AU - Franklin, Bernardo S
AU - Latz, Eicke
AU - Nickenig, Georg
AU - Werner, Nikos
PY - 2012/8
Y1 - 2012/8
N2 - OBJECTIVE: Endothelial microparticles (EMP) are released from activated or apoptotic cells, but their effect on target cells and the exact way of incorporation are largely unknown. We sought to determine the uptake mechanism and the biological effect of EMP on endothelial and endothelial-regenerating cells.METHODS AND RESULTS: EMP were generated from starved endothelial cells and isolated by ultracentrifugation. Caspase 3 activity assay and terminal deoxynucleotidyl transferase dUTP nick end labeling assay showed that EMP protect target endothelial cells against apoptosis in a dose-dependent manner. Proteomic analysis was performed to identify molecules contained in EMP, which might be involved in EMP uptake. Expression of annexin I in EMP was found and confirmed by Western blot, whereas the corresponding receptor phosphatidylserine receptor was present on endothelial target cells. Silencing either annexin I on EMP or phosphatidylserine receptor on target cells using small interfering RNA showed that the uptake of EMP by human coronary artery endothelial cells is annexin I/phosphatidylserine receptor dependent. Annexin I-downregulated EMP abrogated the EMP-mediated protection against apoptosis of endothelial target cells. p38 activation was found to mediate camptothecin-induced apoptosis. Finally, human coronary artery endothelial cells pretreated with EMP inhibited camptothecin-induced p38 activation.CONCLUSIONS: EMP are incorporated by endothelial cells in an annexin I/phosphatidylserine receptor-dependent manner and protect target cells against apoptosis. Inhibition of p38 activity is involved in EMP-mediated protection against apoptosis.
AB - OBJECTIVE: Endothelial microparticles (EMP) are released from activated or apoptotic cells, but their effect on target cells and the exact way of incorporation are largely unknown. We sought to determine the uptake mechanism and the biological effect of EMP on endothelial and endothelial-regenerating cells.METHODS AND RESULTS: EMP were generated from starved endothelial cells and isolated by ultracentrifugation. Caspase 3 activity assay and terminal deoxynucleotidyl transferase dUTP nick end labeling assay showed that EMP protect target endothelial cells against apoptosis in a dose-dependent manner. Proteomic analysis was performed to identify molecules contained in EMP, which might be involved in EMP uptake. Expression of annexin I in EMP was found and confirmed by Western blot, whereas the corresponding receptor phosphatidylserine receptor was present on endothelial target cells. Silencing either annexin I on EMP or phosphatidylserine receptor on target cells using small interfering RNA showed that the uptake of EMP by human coronary artery endothelial cells is annexin I/phosphatidylserine receptor dependent. Annexin I-downregulated EMP abrogated the EMP-mediated protection against apoptosis of endothelial target cells. p38 activation was found to mediate camptothecin-induced apoptosis. Finally, human coronary artery endothelial cells pretreated with EMP inhibited camptothecin-induced p38 activation.CONCLUSIONS: EMP are incorporated by endothelial cells in an annexin I/phosphatidylserine receptor-dependent manner and protect target cells against apoptosis. Inhibition of p38 activity is involved in EMP-mediated protection against apoptosis.
KW - Annexin A1/physiology
KW - Apoptosis/drug effects
KW - Camptothecin/pharmacology
KW - Cell-Derived Microparticles/physiology
KW - Cells, Cultured
KW - Endothelial Cells/physiology
KW - Humans
KW - Receptors, Cell Surface/physiology
KW - p38 Mitogen-Activated Protein Kinases/physiology
U2 - 10.1161/ATVBAHA.112.253229
DO - 10.1161/ATVBAHA.112.253229
M3 - Article
C2 - 22701020
SN - 1079-5642
VL - 32
SP - 1925
EP - 1935
JO - Arteriosclerosis Thrombosis and Vascular Biology
JF - Arteriosclerosis Thrombosis and Vascular Biology
IS - 8
ER -