title: Inhibition of reactive oxygen species down-regulates protein synthesis in RAW 264.7.
abstract: In order to examine the endoplasmic reticulum responses in macrophages, we stimulate macrophage cell line RAW 264.7 by LPS. We found the phosphorylation of eukaryotic initiation factor eIF2alpha and the expression of ATF4, GADD34, and GADD153 in RAW 264.7 cells in late time by the relatively large amount of LPS stimulation. Unexpectedly LPS in the presence of ROS inhibitor N-acetyl-L-cysteine rapidly induced phosphorylation of eIF2alpha and induction of GADD34 expression. We measured intra-cytoplasmic TNFalpha production in LPS stimulated RAW 264.7 cells. TNFalpha production induced by LPS stimulation was greatly suppressed by N-acetyl-L-cysteine. This suppression occurred relatively early, which correlated with early eIF2alpha phosphorylation indicating ER stress mediated shutoff of protein synthesis.
authors.affiliation: Department of Immunology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi 466-8550, Japan.
authors.forename: Kenya
authors.initials: K
authors.lastname: Kimura
authors.forename: Sachiko
authors.initials: S
authors.lastname: Ito
authors.forename: Masato
authors.initials: M
authors.lastname: Nagino
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Isobe
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D051701:Activating Transcription Factor 4 / Q000378:metabolism; D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D002460:Cell Line; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism*; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000276:immunology / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D010766:Phosphorylation; D014176:Protein Biosynthesis; D054645:Protein Phosphatase 1; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051742:Transcription Factor CHOP / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D000943:Antigens, Differentiation; C081452:Atf4 protein, mouse; D018797:Cell Cycle Proteins; C497250:Ddit3 protein, mouse; D015852:Eukaryotic Initiation Factor-2; D008070:Lipopolysaccharides; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D051701:Activating Transcription Factor 4; D051742:Transcription Factor CHOP; C513256:Ppp1r15a protein, mouse; D054645:Protein Phosphatase 1; D000111:Acetylcysteine