Anthocyanin prevents CD40-activated proinflammatory signaling in endothelial cells by regulating cholesterol distribution.
OBJECTIVE
Intracellular tumor necrosis factor receptor-associated factors (TRAFs) translocation to lipid rafts is a key element in CD40-induced signaling. The purpose of this study was to investigate the influence of anthocyanin on CD40-mediated proinflammatory events in human endothelial cells and the underlying possible molecular mechanism.


RESULTS
Treatment of endothelial cells with anthocyanin prevented from CD40-induced proinflammatory status, measured by production of IL-6, IL-8, and monocyte chemoattractant protein-1 through inhibiting CD40-induced nuclear factor-kappaB (NF-kappaB) activation. TRAF-2 played pivotal role in CD40-NF-kappaB pathway as TRAF-2 small interference RNA (siRNA) diminished CD40-induced NF-kappaB activation and inflammation. TRAF-2 overexpression increased CD40-mediated NF-kappaB activation. Moreover, TRAF-2 almost totally recruited to lipid rafts after stimulation by CD40 ligand and depletion of cholesterol diminished CD40-mediated NF-kappaB activation. Exposure to anthocyanin not only interrupted TRAF-2 recruitment to lipid rafts but also decreased cholesterol content in Triton X-100 insoluble lipid rafts. However, anthocyanin did not influence the interaction between CD40 ligand and CD40 receptor.


CONCLUSIONS
Our findings suggest that anthocyanin protects from CD40-induced proinflammatory signaling by preventing TRAF-2 translocation to lipid rafts through regulation of cholesterol distribution, which thereby may represent a mechanism that would explain the anti-inflammatory response of anthocyanin.
Xia
Min
M
Department of Nutrition, School of Public Health, Sun Yat-Sen University, Guangzhou, Guangdong Province, PR China 510080.
Ling
Wenhua
W
Zhu
Huilian
H
Wang
Qing
Q
Ma
Jing
J
Hou
Mengjun
M
Tang
Zhihong
Z
Li
Lan
L
Ye
Qinyuan
Q
D000704:Analysis of Variance; D000872:Anthocyanins / Q000494:pharmacology*; D001161:Arteriosclerosis / Q000188:drug therapy / Q000378:metabolism / Q000517:prevention & control; D019013:CD40 Antigens / Q000494:pharmacology*; D002784:Cholesterol / Q000378:metabolism*; D042783:Endothelial Cells / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D015151:Immunoblotting; D007249:Inflammation / Q000503:physiopathology; D011336:Probability; D012680:Sensitivity and Specificity; D015398:Signal Transduction / Q000187:drug effects*; D047992:TNF Receptor-Associated Factor 2 / Q000032:analysis / Q000378:metabolism*
D000872:Anthocyanins; D019013:CD40 Antigens; D047992:TNF Receptor-Associated Factor 2; D002784:Cholesterol