title: Inhibition by rapamycin of the lipoteichoic acid-induced granulocyte-colony stimulating factor expression in mouse macrophages.
abstract: Granulocyte-colony stimulating factor (G-CSF) is a cytokine which involves in anti-inflammation and inflammation as well. Rapamycin is an inhibitor of mTOR which also plays a role in innate immunity. This study investigated the effect of rapamycin on the lipoteichoic acid (LTA)-induced expression of G-CSF in macrophages and its underlying mechanism. Our data show that LTA induced G-CSF expression in RAW264.7 and bone marrow-derived macrophages and that this effect was inhibited by rapamycin. Analysis of the G-CSF 5' flanking sequence revealed that the -283 to +35 fragment, which contains CSF and octamer elements, was required for maximal promoter activity in response to LTA stimulation. Western blot analyses of proteins that bind to the CSF and octamer element show that LTA increased protein levels of NF-κB, C/EBPβ and Oct-2, and that rapamycin inhibited the LTA-induced increase in Oct-2 protein levels, but not the others. Knockdown of Oct-2 by RNA interference resulted in a decrease in LTA-induced G-CSF mRNA levels. Moreover, forced expression of Oct-2 by transfection with the pCG-Oct-2 plasmid overcame the inhibitory effect of rapamycin on the LTA-induced increase in G-CSF mRNA levels and promoter activity. This study demonstrates that rapamycin reduces G-CSF expression in LTA-treated macrophages by inhibiting Oct-2 expression.
authors.affiliation: Department of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Yuan-Yi
authors.initials: YY
authors.lastname: Chou
authors.forename: Shao-Chun
authors.initials: SC
authors.lastname: Lu
mesh_terms: D024506:5' Flanking Region / Q000235:genetics; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000378:metabolism; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects*; D016179:Granulocyte Colony-Stimulating Factor / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D050813:Octamer Transcription Factor-2 / Q000378:metabolism; D020123:Sirolimus / Q000494:pharmacology*; D013682:Teichoic Acids / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; D008070:Lipopolysaccharides; D016328:NF-kappa B; D050813:Octamer Transcription Factor-2; D013682:Teichoic Acids; D016179:Granulocyte Colony-Stimulating Factor; C009900:lipoteichoic acid; D020123:Sirolimus