Abstract P298: Probucol Inhibits Oxidized Low-Density Lipoprotein--Induced Immune Maturation of Dendritic Cells via Heme Oxygenase 1
The anti-atherosclerotic mechanism of Probucol remains to be elucidated. Studies confirmed the key role of Dendritic Cells (DCs) and cytoprotective role of heme oxygenase 1(HO1) in the development of atherosclerosis. Here, we tested the hypothesis that probucol exerts is anti-atherosclerotic effect by inhibiting maturation of DCs via HO1.
[Method]Immature DCs were derived from purified human monocytes; HO1 siRNA, probucol ,ox-LDL or LDL was added to different groups of medium. The maturation markers of DCs were analyzed by Flow cytometric analysis, including CD1a, CD40, CD86, HLA-DR, endocytosis function and the cytokines secretions of culture supernatants (IL-4,TNF-α) by ELISA. The expression of HO1, STAT1 (signal transducers and activators of transcription 1) and STAT1(Tyr 701) phosphorylation were analyzed by Westernblot and the expression of CIITA(MHC II transactivator) by Real Time PCR.
[Results] Ox-LDL promoted immune maturation of DCs : MIF of CD86,CD 40, CD1a and HLA-DR was significantly increased after ox-LDL stimulation (7697±672 vs 2120±662, 7844±754 vs 843±109 ,323±31 vs 272±14,2636±173 vs 1443±45,respectively); decreased endocytosis function (26256±354 vs 34511±3078); increased TNF-α(43±5 vs 30±0.3 pg/ml), suppressed IL-4 (852±9 vs 793±11 pg/ml)2. Probucol inhibited immune maturation of DCs ,which was most obviously in ox-LDL treated group : MIF of CD 86 CD 40, CD1a and HLA-DR was significantly decreased after probucol treatment (7697±672 vs 3202±660,7844±754 vs 843±109,323±31 vs 56±31, 2636±173 vs 304±60), endocytosis (26256±1689 vs 109568±4195), TNF-α(43±5 vs 14±0.6 pg/ml), IL-4(793±11 vs 1037±17 pg/ml) (P<0.05). 3. After silencing of the expression of HO-1 by siRNA, immune maturation markers of DCs were increased than respective non-silencing group ,such as CD86, CD 40, HLA-DR (549±19 vs 353±23, 2645±307vs 524±119,1179±66 vs 766±23,respectivly), endocytosis function were suppressed (7408±229 vs 10860±706), TNF-αwas increased (22±0.2 vs 14±0.6 pg/ml), IL-4 was decreased (926±2 vs 1037±17 pg/ml) (P<0.05), STAT1(701) phosphorylation and CIITA expression level were increased.
[Conclusion]Probucol significantly inhibited immune maturation of DCs and is associated with HO1, STAT1/CIITA signaling pathway.
- © 2011 by American Heart Association, Inc.