title: Bamboo extract reduces interleukin 6 (IL-6) overproduction under lipotoxic conditions through inhibiting the activation of NF-κB and AP-1 pathways.
abstract: Interleukin 6 (IL-6) is an inflammatory cytokine overexpressed in obese individuals that contributes to the development of diseases such as insulin resistance, type 2 diabetes, and cardiovascular disease. This study investigated the inhibitory effect of an extract from the bamboo Phyllostachys edulis (BEX) on lipotoxicity-induced over-production of IL-6 in metabolic cell lines. Palmitic acid (PA, 0.4mM) was used to induce lipotoxicity in murine C2C12, 3T3-L1, and Hepa6 cells. Both intra- and extra-cellular protein concentrations of IL-6 were measured in the three cell lines after PA treatment with or without the presence of BEX using cytometric bead assays. IL-6 mRNA levels were quantified using real-time PCR, and nuclear concentrations of c-fos, p50 and p65 proteins were measured using DNA-binding ELISA in 3T3-L1 cells. Lipotoxicity increased IL-6 protein concentration in both cytosol and media collected from myoblast and myotube C2C12, as well as preadipose and adipose 3T3-L1, and the presence of BEX (0.5%, v/v) effectively inhibited this overproduction. IL-6 protein expression in hepatic Hepa6 cells was less affected by lipotoxicity. BEX significantly ameliorated PA-induced upregulation of IL-6 mRNA, which correlated with a reduction in nuclear translocation of p50, p65, and c-fos proteins with the presence of BEX, indicating inhibition of NF-κB and AP-1 activation. In summary, BEX inhibits lipotoxicity-induced IL-6 overproduction in muscle and adipose cell lines through the NF-κB and AP-1 pathways, implicating a potential application of this natural product as a cost-effective anti-inflammation nutraceutical.
authors.affiliation: Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street BSB 222, Honolulu, HI 96813, USA.
authors.forename: Jason K
authors.initials: JK
authors.lastname: Higa
authors.forename: Jun
authors.initials: J
authors.lastname: Panee
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D031723:Bambusa / Q000737:chemistry*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D005786:Gene Expression Regulation / Q000187:drug effects; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism*; D052002:NF-kappa B p50 Subunit / Q000378:metabolism; D019308:Palmitic Acid / Q000633:toxicity*; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology*; D021381:Protein Transport / Q000187:drug effects; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D051996:Transcription Factor RelA / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D003470:Culture Media; D015850:Interleukin-6; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; D010936:Plant Extracts; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D051996:Transcription Factor RelA; D019308:Palmitic Acid