Luteolin Inhibits Lysophosphatidylcholine-Induced Apoptosis in Endothelial Cells by a Calcium/Mithocondrion/Caspases-Dependent Pathway

Abstract

Luteolin, a naturally occurring polyphenol flavonoid, has demonstrated some beneficial modulation toward the endothelium. This study aims to investigate the effects of luteolin on lysophosphatidylcholine (LPC)-induced apoptosis, a key event in the pathogenesis of atherosclerosis, in endothelial cells. Luteolin reduced not only LPC-induced cell death but also lactate dehydrogenase (LDH) leakage. Luteolin inhibition of LPC-induced apoptosis in endothelial cells demonstrated its protection against the cytotoxicity of LPC. LPC-induced apoptosis is characterized by a calcium-dependent mitochondrial pathway, involving calcium influx, activation of calpains, cytochrome C release and caspases activation. Luteolin reduced calcium influx. It also inhibited calpains activation and prevented the release of cytochrome C from mitochondrion. The inhibition of cytochrome C release by luteolin blocked the activation of caspase-3 and thus prevented subsequent endothelial cell apoptosis. These results suggested that luteolin inhibits LPC-induced apoptosis in endothelial cells through the blockage of the calcium-dependent mitochondrial pathway.

Key words

luteolin - lysophosphatidylcholine - apoptosis - endothelial cells

References

• 1 Sprague E A, Steinbach B L, Nerem R M, Schwartz C J. Influence of a laminar steady-state fluid-imposed wall shear stress on the binding, internalization, and degradation of low density lipoproteins by cultured arterial endothelium.  Circulation. 1987;  76 648-656
• 2 Caplan B A, Schwartz C J. Increased endothelial cell turnover in areas of in vivo Evans blue uptake in the pig aorta.  Atherosclerosis. 1973;  17 401-417
• 3 Kockx M M, De Meyer G R, Muhring J, Jacob W, Bult H, Herman A G. Apoptosis and related proteins in different stages of human atherosclerotic plaques.  Circulation. 1998;  97 2307-2315
• 4 Crisby M, Kallin B, Thyberg J, Zhivotovsky B, Orrenius S, Kostulas V, Nilsson J. Cell death in human atherosclerotic plaques involves both necrosis and apoptosis.  Atherosclerosis. 1997;  130 17-27
• 5 Chen J, Mehta J L, Haider N, Zhang X, Narula J, Li D. Role of caspases in Ox-LDL-induced apoptotic cascade in human coronary artery endothelial cells.  Circ Res. 2004;  94 370-376
• 6 Vindis C, Elbaz M, Escargueil-Blanc I, Augé N, Heniquez A, Thiers J C, Nègre-Salvayre A, Salvayre R. Two distinct calcium-dependent mitochondrial pathways are involved in oxidized LDL-induced apoptosis.  Arterioscler Thromb Vasc Biol. 2005;  25 639-645
• 7 Tsutsumi H, Kumagai T, Naitoo S, Ebina K, Yokota K. Synthetic peptide (P-21) derived from Asp-hemolysin inhibits the induction of apoptosis on HUVECs by lysophosphatidylcholine.  Biol Pharm Bull. 2006;  29 907-910
• 8 Kaneko T, Baba N. Protective effect of flavonoids on endothelial cells against linoleic acid hydroperoxide-induced toxicity.  Biosci Biotechnol Biochem. 1999;  63 323-328
• 9 Kozakai T, Yamanaka A, Ichiba T, Toyokawa T, Kamada Y, Tamamura T, Ichimura T, Maruyama S. Luteolin inhibits endothelin-1 secretion in cultured endothelial cells.  Biosci Biotechnol Biochem. 2005;  69 1613-1615
• 10 Takano-Ishikawa Y, Goto M, Yamaki K. Inhibitory effects of several flavonoids on E-selectin expression on human umbilical vein endothelial cells stimulated by tumor necrosis factor-alpha.  Phytother Res. 2003;  17 1224-1227
• 11 Jeong Y J, Choi Y J, Choi J S, Kwon H M, Kang S W, Bae J Y, Lee S S, Kang J S, Han S J, Kang Y H. Attenuation of monocyte adhesion and oxidised LDL uptake in luteolin-treated human endothelial cells exposed to oxidised LDL.  Br J Nutr. 2007;  97 447-457
• 12 Alexandra H, Kathrin H, Ulrikf R, Christoph W, Jan G. Stimulation of NADPH oxidase by oxidized low-density lipoprotein induces proliferation of human vascular endothelial cells.  J Am Soc Nephrol. 2000;  11 1819-1825
• 13 Dimmeler S, Hermann C, Zeiher A M. Apoptosis of endothelial cells. Contribution to the pathophysiology of atherosclerosis?.  Eur Cytokine Netw. 1998;  9 697-698
• 14 Mallat Z, Tedgui A. Apoptosis in the vasculature: mechanisms and functional importance.  Br J Pharmacol. 2000;  130 947-962
• 15 Geng Y J, Libby P. Progression of atheroma: a struggle between death and procreation.  Arterioscler Thromb Vasc Biol. 2002;  22 1370-1380
• 16 Stefanec T. Endothelial apoptosis: could it have a role in the pathogenesis and treatment of disease?.  Chest. 2000;  117 841-854
• 17 Switzer S, Eder H A. Transport of lysolectithin by albumin in human and rat plasma.  J Lipid Res. 1965;  4 506-511
• 18 Klopfenstein W E. Enthalpy change of binding lysolecithin to serum albumin.  Biochim Biophys Acta. 1969;  181 323-325
• 19 Joles J A, Willekes-Koolschijn N, Scheek L M, Koomans H A, Rabelink T J, van Tol A. Lipoprotein phospholipid composition and LCAT activity in nephrotic and analbuminemic rats.  Kidney Int. 1994;  46 97-104
• 20 Vuong T D, Stroes E S, Willekes-Koolschijn N, Rabelink T J, Koomans H A, Joles J A. Hypoalbuminemia increases lysophosphatidylcholine in low-density lipoprotein of normocholesterolemic subjects.  Kidney Int. 1999;  55 1005-1010
• 21 Mcintyre T M, Zimmerman G A, Prescott S M. Biologically active oxidized phospholipids.  J Biol Chem. 1999;  274 25189-25192
• 22 Salvayre R, Auge N, Benoist H, Negre-Salvayre A. Oxidized LDL-induced apoptosis.  Biochim Biophys Acta. 2002;  1585 213-221
• 23 Napoli C. Oxidation of LDL, atherogenesis, and apoptosis.  Ann NY Acad Sci. 2003;  1010 698-709
• 24 Escargueil-Blanc I, Meilhac O, Pieraggi M T, Arnal J F, Salvayre R, Nègre-Salvayre A. Oxidized LDLs induce massive apoptosis of cultured human endothelial cells through a calcium-dependent pathway. Prevention by aurintricarboxylic acid.  Arterioscler Thromb Vasc Biol. 1997;  17 331-339
• 25 Orrenius S, Zhivotovsky B, Nicotera P. Regulation of cell death: the calcium-apoptosis link.  Nat Rev Mol Cell Biol. 2003;  4 552-565
• 26 Walter D H, Haendeler J, Galle J, Zeiher A M, Dimmeler S. Cyclosporin A inhibits apoptosis of human endothelial cells by preventing release of cytochrome C from mitochondria.  Circulation. 1998;  98 1153-1157
• 27 Zamzami N, Marchetti P, Castedo M, Hirsch T, Susin S A, Masse B, Kroemer G. Inhibitors of permeability transition interfere with the disruption of the mitochondrial transmembrane potential during apoptosis.  FEBS Lett. 1996;  384 53-57
• 28 Li P, Nijhawan D, Budihardjo I, Srinivasula S M, Ahmad M, Alnemri E S, Wang X. Cytochrome c and dATP-dependent formation of Apaf-1/caspase-9 complex initiates an apoptotic protease cascade.  Cell. 1997;  91 479-489
• 29 Kluck R M, Bossy-Wetzel E, Green D R, Newmeyer D D. The release of cytochrome c from mitochondria: a primary site for Bcl-2 regulation of apoptosis.  Science. 1997;  275 1132-1136