Acemannan, a beta-(1,4)-acetylated mannan, induces nitric oxide production in macrophage cell line RAW 264.7.
Acemannan is a polydispersed beta-(1,4)-linked acetylated mannan with antiviral properties. It is an immunomodulator, and studies in our laboratory have shown that it causes activation of macrophages. Inducible NO synthase is generally expressed after transcriptional induction and is known to mediate some of the cytotoxic action of activated macrophages. Acemannan, in the presence of interferon-gamma, greatly increased the synthesis of NO in RAW 264.7 cells. This increase was preceded by increased expression of mRNA for the inducible form of macrophage NO synthase. Preincubation with pyrrolidine dithiocarbamate inhibited the induction, indicating the involvement of nuclear factor-kappa B. These results suggest that acemannan causes the activation of macrophages by increasing the level of NO synthase at the level of transcription.
Ramamoorthy
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Department of Veterinary Pathobiology, Texas A & M University, College Station 77843, USA. IOr7859@rigel.tamu.edu
Kemp
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Tizard
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D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D004790:Enzyme Induction; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D008351:Mannans / Q000494:pharmacology*; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis / Q000235:genetics; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D013859:Thiocarbamates / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects
D000975:Antioxidants; D008070:Lipopolysaccharides; D008351:Mannans; D011500:Protein Synthesis Inhibitors; D011759:Pyrrolidines; D012333:RNA, Messenger; D013859:Thiocarbamates; C020972:pyrrolidine dithiocarbamic acid; D009569:Nitric Oxide; D007371:Interferon-gamma; D003513:Cycloheximide; D019001:Nitric Oxide Synthase; C058414:acemannan