Interleukin 8 is differently expressed and modulated by PAR-1 activation in early and late endothelial progenitor cells.
The proinflammatory chemokine interleukin 8 exerts potent angiogenic effects on endothelial cells by interacting with its receptors CXCR1 and CXCR2. As thrombin is also a potent inflammatory factor, and as endothelial progenitor cells (EPC) express functional PAR-1 thrombin receptor, we examined whether PAR-1 stimulation interferes with the IL-8 pathway in EPC. EPC were obtained from adult blood (AB) and cord blood (CB). The effect of PAR-1 stimulation by the peptide SFLLRN on IL-8, CXCR1 and CXCR2 expression was examined by RTQ-PCR and at the protein level in AB and CB late EPC and in AB early EPC. Specific siRNA was used to knock down PAR-1 expression. The IL-8 gene was expressed strongly in AB early EPC and moderately in late EPC. In contrast, CXCR1 and CXCR2 gene expression was restricted to AB early EPC. The IL-8 level in AB early EPC conditioned medium was high in basal conditions and did not change after PAR-1 activation. By contrast, IL-8 secretion by late EPC was low in basal conditions and strongly up-regulated upon PAR-1 activation. PAR-1 activation induced a number of genes involved in activating protein-1 (AP-1) and nuclear factor (NF)-kappaB pathways. Conditioned medium of PAR-1-activated late EPC enhanced the migratory potential of early EPC, and this effect was abrogated by blocking IL-8. Target-specific siRNA-induced PAR-1 knockdown, and fully inhibited PAR-1-induced IL-8 synthesis. In conclusion, PAR-1 activation induces IL-8 synthesis by late EPC. This could potentially enhance cooperation between late and early EPC during neovascularization, through a paracrine effect.
Smadja
David M
DM
Université Paris Descartes, Faculté de Pharmacie, Paris, France.|Inserm U765, Paris, France.|AP-HP, Hòpital Européen Georges Pompidou, Paris, France.
Bièche
Ivan
I
Université Paris Descartes, Faculté de Pharmacie, Paris, France.|Inserm U745, Paris, France.
Susen
Sophie
S
Inserm U765, Paris, France.
Mauge
Laetitia
L
Inserm U765, Paris, France.|AP-HP, Hòpital Européen Georges Pompidou, Paris, France.
Laurendeau
Ingrid
I
Université Paris Descartes, Faculté de Pharmacie, Paris, France.|Inserm U745, Paris, France.
d'Audigier
Clément
C
Inserm U765, Paris, France.
Grelac
Françoise
F
Inserm U765, Paris, France.
Emmerich
Joseph
J
Université Paris Descartes, Faculté de Pharmacie, Paris, France.|Inserm U765, Paris, France.|AP-HP, Hòpital Européen Georges Pompidou, Paris, France.
Aiach
Martine
M
Université Paris Descartes, Faculté de Pharmacie, Paris, France.|Inserm U765, Paris, France.|AP-HP, Hòpital Européen Georges Pompidou, Paris, France.
Gaussem
Pascale
P
Université Paris Descartes, Faculté de Pharmacie, Paris, France.|Inserm U765, Paris, France.|AP-HP, Hòpital Européen Georges Pompidou, Paris, France.
D000328:Adult; D001483:Base Sequence; D015153:Blotting, Western; D017931:DNA Primers; D004730:Endothelium, Vascular / Q000166:cytology; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D016209:Interleukin-8 / Q000378:metabolism*; D044463:Receptor, PAR-1 / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers; D016209:Interleukin-8; D044463:Receptor, PAR-1