SIRT1 regulates CD40 expression induced by TNF-α via NF-ĸB pathway in endothelial cells.
BACKGROUND
Compelling evidence suggests that SIRT1, NAD(+)-dependent class III protein deacetylase, plays an important role in the prevention and treatment of atherosclerosis by counteracting inflammation. Cluster of differentiation 40 (CD40), as a pro-inflammatory cytokine, has been shown to participate in the pathophysiology of atherosclerosis. The relationship between SIRT1 and CD40, however, remained elusive. The present study was thus designed to explore the potential effect of SIRT1 on CD40 expression induced by tumor necrosis factor-α (TNF-α) and to disclose the underlying mechanism in CRL-1730 endothelial cells.


METHODS
mRNA and protein expressions were identified by quantitative real-time PCR and Western blot respectively. Subcellular localization of SIRT1 was detected by immunofluorescence analysis. SIRT1 small-interfering RNA (siRNA) was carried out for mechanism study.


RESULTS
TNF-α reduced SIRT1 expression and induced CD40 expression in CRL-1730 endothelial cells in a time- and concentration- dependent manner. Pretreatment with resveratrol (a potent SIRT1 activator) inhibited TNF-α-induced CD40 expression, while pretreatment with nicotinamide (class b HDACs inhibitor nicotinamide) or sirtinol (a known SIRT1 inhibitor), especially SIRT1 siRNA significantly augmented TNF-α-induced CD40 expression. The frther sudy idicated that PDTC (NF-ĸB inhibitor) pretreatment attenuated TNF-α-induced CD40 expression, and SIRT1 siRNA significantly augmented TNF-α-induced acetylated-NF-ĸB p65 (Lys310) expression.


CONCLUSIONS
The present study provides the direct evidence that SIRT1 can inhibit TNF-α- induced CD40 expression in CRL-1730 endothelial cells by deacetylating the RelA/p65 subunit of NF-ĸB at lysine 310, which provides new insights into understanding of the anti-inflammatory and anti-athroscerotic actions of SIRT1.
Department of Pharmacology, School of Medicine, Xi'an Jiaotong University, Xi'an, PR China.
Lina
L
Yang
Jiye
J
Zhang
Chunfang
C
Yan
Jun
J
Zhou
Rong
R
Lin
Qinqin
Q
Lin
Weirong
W
Wang
Kaifan
K
Zhang
Guangde
G
Yang
Xiaoli
X
Bian
Aiguo
A
Zeng
D019013:CD40 Antigens / Q000096:biosynthesis*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism*; D056564:Sirtuin 1 / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D019013:CD40 Antigens; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; C447939:SIRT1 protein, human; D056564:Sirtuin 1