FIGURE 7.

SMP_LPS induce endothelial senescence through MAP‐Kinase and PI3 kinase pathways, and via neutrophil‐derived MPs. A, P1ECs were incubated either with 100 μmol/L H₂O₂, or a selective inhibitor of PI3 kinase (PI3Ki, LY294002, 10 μmol/L), p38 MAPK (p38i, SB203580, 10 μmol/L) or ERK ½ (ERKi, PD98059, 10 μmol/L) for 1 h prior to the addition of 10 nmol/L SMP_LPS or SMP_PMA/I for 48 h before the determination of SA‐β‐gal activity. B, Effect of the removal of either CD31+/CD11b+‐MPs or CD31+/CD11b+/CD11b/c+‐ MPs on the endothelial pro‐senescent effect of SMP_LPS. P1ECs were incubated with 10 nmol/L of SMP_LPS and with non‐depleted suspensions for 48 h before the determination of SA‐β‐gal activity. C, Characterization of the cell origin of SMP shed from splenocytes stimulated by LPS or PMA/calcium ionophore. After 24‐h stimulation, SMPs were measured in cell supernatants by pro‐thrombinase assay and expressed as nmol/L PhtdSer per 100.10⁶ cells. Characterization of the SMP cell origin was performed by capturing SMPs onto biotinylated antibodies directed against leucocyte CDs before quantification by pro‐thrombinase assay. Data are expressed as mean ± SEM of experiments performed at least on three different cell cultures. AV: Annexin V. *P < .05, **P < .01