Thromb Haemost 2006; 95(01): 142-150
DOI: 10.1160/TH05-07-0505
Cellular Proteolysis and Oncology
Schattauer GmbH

Dual effect of apolipoprotein(a) on plasmin(ogen)-induced apoptosis through modulation of cell detachment of adherent cells

Benoît Ho-Tin-Noé
1   INSERM U698, Paris, France
2   Université Paris Denis Diderot, Paris, France
,
Olivier Meilhac
1   INSERM U698, Paris, France
2   Université Paris Denis Diderot, Paris, France
,
Patrick Rossignol
1   INSERM U698, Paris, France
2   Université Paris Denis Diderot, Paris, France
,
H. Roger Lijnen
3   Center for Molecular and Vascular Biology, Katholieke Universitet Leuven, Belgium
,
Eduardo Anglés-Cano
1   INSERM U698, Paris, France
2   Université Paris Denis Diderot, Paris, France
› Author Affiliations
Financial support: This study was funded by the INSERM and grants Adrienne et Pierre Sommer from the Fondation de France to E AC, and project 04CV from the Leducq Foundation.
Further Information

Publication History

Received 19 July 2005

Accepted after resubmission 01 November 2005

Publication Date:
28 November 2017 (online)

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Summary

Because of its structural homology with plasminogen, the apolipoprotein(a) [apo(a)] component of the athero-thrombogenic lipoprotein(a) [Lp(a)] particle inhibits plasminogen binding and activation onto fibrin as well as the subsequent fibrinolysis. In a similar manner, apo(a) may also interfere with plasmin(ogen)-induced cell detachment and apoptosis of adherent cells. To investigate this hypothesis, we studied the effect of a recombinant apo(a) [r-apo(a)] on plasminogen activation-induced apoptosis of vascular smooth muscle cells (VSMCs) and fibroblasts-like CHO-K1 cells. We demonstrate for the first time that apo(a) displays a concentration-dependent biphasic, enhancing/preventing effect on plasmin(ogen) induced cell detachment of VSMCs and CHO-K1 cells. Our results show that r-apo(a) binds to these cells with higher affinity than plasminogen [Kd = 0.9 ± 0.2 µM for plasminogen, Kd = 1.77 ± 0.34 nM for r-apo(a)] in a lysine-dependent manner. At high r-apo(a)/plasminogen ratios, their competitive interaction results in a partial inhibition of plasminogen activation by cell-bound t-PA. As a consequence, r-apo(a) prevents plasmin(ogen)-induced cell detachment and apoptosis. Surprisingly,at low r-apo(a)/plasminogen ratios,an enhancement in plasmin(ogen)-induced cell detachment and apoptosis was observed. This effect was shown to be “plasmin-selective” as r-apo(a) was unable to potentiate cell detachment induced by human neutrophil elastase and trypsin. Altogether these data are consistent with a new mechanism of apo(a)/plasmin(ogen) interactions that may contribute to the atherothrombogenic potential of Lp(a).