title: Repression of proinflammatory gene expression by lipid extract of Nostoc commune var sphaeroides Kützing, a blue-green alga, via inhibition of nuclear factor-kappaB in RAW 264.7 macrophages.
abstract: We investigated whether lipid extract from a blue-green alga, N commune, modulates proinflammatory gene expression in RAW 264.7 macrophages. The cells were incubated with N commune lipid extract (0-100 microg/mL) and subsequently activated by LPS (100 ng/mL). Quantitative real-time PCR analysis showed that mRNA abundance of proinflammatory mediators, including TNF-alpha, COX-2, IL-1beta, IL-6, and iNOS, was significantly reduced by N commune lipid extract in a dose-dependent manner. Secretion of TNF-alpha and IL-1beta into cell culture medium was also significantly decreased by N commune lipid extract. Thin-layer chromatography-densitometry analysis showed that N commune lipid extract contained approximately 15% of fatty acids. To determine whether the inhibition of proinflammatory mediator production by N commune lipid extract is primarily conferred by fatty acids in the lipid extract, macrophages were incubated with 100 microg/mL of N commune lipid extract or 15 microg/mL of a fatty acid mixture, which was formulated to reflect the fatty acid composition of N commune lipid extract. The fatty acid mixture significantly reduced RNA abundance of TNF-alpha and COX-2, but to a lesser extent than did the N commune lipid extract, suggesting the presence of additional bioactive compounds with an antiinflammatory property in the lipid extract. As NF-kappaB is a major regulator for the proinflammatory gene expression, we measured its DNA-binding activity. DNA-binding activity of NF-kappaB was significantly reduced by N commune lipid extract. In conclusion, our study suggests that N commune lipid extract represses the expression of proinflammatory genes in RAW 264.7 macrophages, at least in part, by inhibiting the activation of NF-kappaB pathway.
authors.affiliation: Department of Nutrition and Health Sciences, University of Nebraska, Lincoln, NE 68583, USA.
authors.forename: Young-Ki
authors.initials: YK
authors.lastname: Park
authors.forename: Heather E
authors.initials: HE
authors.lastname: Rasmussen
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Ehlers
authors.forename: Kara R
authors.initials: KR
authors.lastname: Blobaum
authors.forename: Fan
authors.initials: F
authors.lastname: Lu
authors.forename: Vicki L
authors.initials: VL
authors.lastname: Schlegal
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Carr
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Lee
mesh_terms: D002478:Cells, Cultured; D002855:Chromatography, Thin Layer; D003720:Densitometry; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D008055:Lipids / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000276:immunology*; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D050501:Nostoc commune / Q000737:chemistry*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D008055:Lipids; D008070:Lipopolysaccharides; D016328:NF-kappa B; D012333:RNA, Messenger