Polyinosinic acid induces TNF and NO production as well as NF-kappaB and AP-1 transcriptional activation in the monocytemacrophage cell line RAW 264.7.
OBJECTIVE
This study evaluates the poly inosinic acid (poly I)-induced activation in the murine monocytemacrophage cell line RAW 264.7, which led to an inflammatory phenotype.


METHODS
RAW 264.7, and WEHI 164 cell lines were used.


RESULTS
The activation process is characterized by the acquisition of a mature macrophage morphology and the production of inflammatory mediators tumor necrosis factor (TNF) and nitric oxide (NO). The activation by poly I has distinctive features. Thus, poly I induced an increase in nuclear factor kappaB (NF-kappaB) transcriptional activity due to a long-term degradation of inhibitory NF-kappaB (IkappaB) beta while lipopolysaccharide (LPS) induced the degradation of both IkappaBalpha and IkappaBbeta. Poly I also induced an increase in activator protein 1 (AP-1) transcriptional activity, possibly due to the activation of the mitogen activated protein kinases (MAPKs) ERK, Jun N terminal kinase (JNK) and p38. Dextran sulphate (DS) efficiently inhibited the activation induced by poly I including the production of the inflammatory mediators. Dextran sulphate also inhibited AP-1 and NF-kappaB transcriptional activities in poly I-stimulated cells. RAW 264.7 cells express macrophage scavenger receptor 1 (Msr1) type I and Msr1 type II that are differently up-regulated upon treatment with poly I.


CONCLUSIONS
The results presented demonstrate that the well-known blocker of scavenger receptors poly I activates macrophages to produce TNF and NO, triggering specific signal transduction pathways.
Campa
V M
VM
Instituto Universitario de Oncología del Principado de Asturias and Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, 33071 Oviedo, Spain.
Iglesias
J M
JM
Carcedo
M T
MT
Rodríguez
R
R
Riera
J
J
Ramos
S
S
Lazo
P S
PS
D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D016264:Dextran Sulfate / Q000494:pharmacology; D003911:Dextrans / Q000494:pharmacology; D020672:I-kappa B Proteins / Q000378:metabolism; D007249:Inflammation; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008070:Lipopolysaccharides / Q000737:chemistry; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D011069:Poly I / Q000494:pharmacology*; D011971:Receptors, Immunologic / Q000378:metabolism; D051116:Receptors, Scavenger; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D003911:Dextrans; C083487:I kappa B beta protein; D020672:I-kappa B Proteins; D008070:Lipopolysaccharides; D016328:NF-kappa B; C000606205:Nfkbia protein, mouse; D011971:Receptors, Immunologic; D051116:Receptors, Scavenger; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha; D011069:Poly I; D009569:Nitric Oxide; D016264:Dextran Sulfate; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases