Objective: Atherosclerosis is an inflammatory condition, and rupture of atherosclerotic plaques is a major cause of cardiovascular disease (CVD). Lysophosphatidylcholine (LPC) is generated in low-density lipoprotein.(LDL) during oxidation and/or enzymatic modification and has been implicated in atherosclerosis. Annexin A5 (ANXA5) is an antithrombotic and atheroprotective plasma protein. Here, we demonstrate novel pro-inflammatory and atherogenic properties of LPC, and inhibitory effects of ANXA5.Methods: Endothelial cells and macrophages (differentiated from, THP-1 a monocytic cell line) were co-cultured. Expression of MMP-9 and OxLDL uptake by macrophages were studied by flow cytometry. The effect of LPC on leukotriene B4 (LTB4) synthesis in macrophages was studied by enzyme immunoassay (EIA). Chemotactic properties of LPC were investigated using a mouse intra-peritoneal recruitment model.Results: Co-culture of macrophages and endothelial cells enhanced MMP-9 expression in both cell types. This effect was increased by LPC and diminished by ANXA5. Likewise, LPC induced LTB4 production by macrophages, whereas native LDL or phosphatidylcholine (PTC) had no effect. ANXA5 inhibited uptake of OxLDL in macrophages. LPC induced cell infiltration in vivo, as determined by increased cell count in mouse peritoneal exudates, and this effect was inhibited by ANXA5.Conclusions: ANXA5 could potentially play an important protective role in both atherogenesis and atherosclerotic plaque rupture by reducing pro-inflammatory effects of OxLDL and LPC as well as inhibiting OxLDL binding and uptake by macrophages. The possibility that ANXA5 could be developed into a novel therapy against CVD deserves further study. (C) 2013 Published by Elsevier Inc.

The effect of cyclosporin A (CsA) on prostaglandin E2 (PGE2) production in human gingival fibroblasts challenged with tumor necrosis factor alpha (TNF-alpha) was studied. TNF-alpha (1-100 ng/ml) dose-dependently stimulated PGE2 formation in 24 h cultures. CsA (1-100 ng/ml) did not induce PGE2 formation itself but potentiated TNF-alpha induced PGE2 formation in gingival fibroblasts in a manner dependent on the concentrations of both CsA and TNF-alpha. TNF-alpha (10 ng/ml) stimulated the release of [3H]-arachidonic acid (AA) from prelabelled fibroblasts that was potentiated by CsA (100 ng/ml). Addition of exogenous unlabelled AA (5-20 microM/ml) to the cells resulted in enhanced PGE2 formation that was not potentiated by CsA (100 ng/ml). Furthermore, CsA (100 ng/ml) did not further increase the level of cyclooxygenase-2 mRNA induced by TNF-alpha (10 ng/ml), although PGE2 formation was enhanced. The results indicate that CsA and TNF-alpha act in concert on PGE2 formation in gingival fibroblasts, which may be of importance in the pathogenesis of gingival overgrowth induced by the drug.