Inhibition of nitric oxide synthesis by interleukin-4 may involve inhibiting the activation of protein kinase C epsilon.
The murine macrophage cell line, J774, when activated with interferon-gamma (IFN-gamma), expressed high level of inducible nitric oxide synthase (iNOS) and bound significantly more [3H]-phorbol-dibutyrate (PBu2) compared to non-activated cells. The increased PBu2 binding to the particulate fraction of the cells is a measure of activation and translocation of protein kinase C (PKC). Both the expression of iNOS and the enhanced. PBU2 binding in the activated J774 cells were significantly inhibited by the pretreatment of the cells with murine recombinant interleukin-4 (IL-4). Stimulation of J774 cells by IFN-gamma and lipopolysaccharide results in the translocation predominantly of the epsilon isoform of PKC (PKC-epsilon), and this is inhibited by IL-4. The inhibition of PKC activation was also evident by measuring the PKC activity in the cytosolic-fraction of the IL-4-treated cells. Activated J774 cells pretreated with IL-4 or a PKC-specific inhibitor (RO31-8220) failed to express mRNA of iNOS analyzed by PCR. These results, therefore, suggest that the inhibition of nitric oxide synthesis in activated murine macrophages by IL-4 is at the transcriptional level and may involve the inhibition of the activation of PKC-epsilon.
Sands
W A
WA
Department of Immunology, University of Glasgow, Western Infirmary.
Bulut
V
V
Severn
A
A
Xu
D
D
Liew
F Y
FY
D000594:Amino Acid Oxidoreductases / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D002451:Cell Compartmentation / Q000187:drug effects; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D004789:Enzyme Activation / Q000187:drug effects; D015847:Interleukin-4 / Q000494:pharmacology*; D007527:Isoenzymes / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase; D011493:Protein Kinase C / Q000378:metabolism*; D051744:Protein Kinase C-epsilon; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic
D017931:DNA Primers; D007527:Isoenzymes; D012333:RNA, Messenger; D015847:Interleukin-4; D009569:Nitric Oxide; D000242:Cyclic AMP; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; C497256:Prkce protein, mouse; D011493:Protein Kinase C; D051744:Protein Kinase C-epsilon