Sulforaphane inhibits endothelial lipase expression through NF-κB in endothelial cells.
OBJECTIVE
Endothelial lipase (EL) is a new member of triacylglycerol lipase family that has been shown to decrease high-density lipoprotein (HDL) cholesterol levels leading to increased risk of atherosclerosis. Its expression is increased during inflammation and by inflammatory cytokines. Sulforaphane (SFN) is a naturally occurring isothiocyanate present in cruciferous vegetables that has antioxidant and anti-inflammatory effects. Nuclear factor (NF)-κB is one of the molecular targets for SFN-mediated protective effects. Our aim was therefore to assess whether SFN could impact on EL expression via modulation of NF-κB pathway.


RESULTS
Quantitative PCR and Western blot results demonstrated that SFN inhibited tumor necrosis factor (TNF)-α-mediated induction of EL in human umbilical vein endothelial cells (HUVEC). Lentiviral transduction of HUVEC with mutated form of IκB-α (IκBM) as well as silencing of NF-κB subunit p65 using RNA interference revealed that TNF-α-mediated induction of EL is mediated through NF-κB pathway. In addition, a total of five NF-κB binding sites were found in LIPG gene, which encodes EL. SFN inhibited binding of NF-κB to these sites analyzed by chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift assay (EMSA). SFN also inhibited TNF-α mediated phosphorylation of IκB kinase (IKK) 1/2 and IκB-α.


CONCLUSIONS
Collectively, these results indicate that SFN inhibits EL expression via inhibition of NF-κB which may have a beneficial effect on HDL cholesterol levels.
Kivelä
Annukka M
AM
The Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, Neulaniementie 2, FIN-70211 Kuopio, Finland.
Mäkinen
Petri I
PI
Jyrkkänen
Henna-Kaisa
HK
Mella-Aho
Eero
E
Xia
Yifeng
Y
Kansanen
Emilia
E
Leinonen
Hanna
H
Verma
Inder M
IM
Ylä-Herttuala
Seppo
S
Levonen
Anna-Liisa
AL
D000975:Antioxidants / Q000737:chemistry; D050197:Atherosclerosis / Q000378:metabolism; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D017879:Isothiocyanates / Q000737:chemistry; D008049:Lipase / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D008954:Models, Biological; D016328:NF-kappa B / Q000378:metabolism*; D011485:Protein Binding; D013454:Sulfoxides; D013861:Thiocyanates / Q000494:pharmacology*; D014471:Umbilical Veins / Q000166:cytology; D014675:Vegetables
D000975:Antioxidants; D017879:Isothiocyanates; D016328:NF-kappa B; D013454:Sulfoxides; D013861:Thiocyanates; D051550:I-kappa B Kinase; C410382:LIPG protein, human; D008049:Lipase; C016766:sulforaphane