Activated lymphocytes increase expression of 5-lipoxygenase and its activating protein in THP-1 cells.
The aim of this study was to investigate the regulation of the 5-lipoxygenase pathway of arachidonic acid metabolism by lymphocytes using the monocyte-like cell line, THP-1. When THP-1 cells were incubated over 4-7 days in 10% supernatant from lectin-activated human lymphocytes, their capacity to synthesize 5-lipoxygenase products was significantly increased. In contrast, the supernatant from nonactivated lymphocytes had no effect. The increase in capacity to synthesize 5-lipoxygenase products was mimicked by the addition of either granulocyte macrophage colony-stimulating factor (GM-CSF) or interleukin-3. These increases in synthetic capacity reflected increased enzymatic activity. Increased immunoreactive protein and mRNA for the enzymes 5-lipoxygenase and 5-lipoxygenase-activating protein were also found in cells conditioned with activated lymphocyte supernatants. Furthermore, the increase in mRNA for both enzymes was not blocked by cycloheximide, suggesting that the effect on steady-state mRNA levels does not require the synthesis of new protein. The increase in mRNA could be reproduced by GM-CSF. We conclude that lymphocytes can regulate the expression of 5-lipoxygenase in THP-1 cells over a period of days via the release of soluble factors.
Ring
W L
WL
Department of Medicine, Department of Veterans Affairs Medical Center, San Diego, California 92161, USA.
Riddick
C A
CA
Baker
J R
JR
Glass
C K
CK
Bigby
T D
TD
D058927:5-Lipoxygenase-Activating Proteins; D001094:Arachidonate 5-Lipoxygenase / Q000096:biosynthesis*; D002352:Carrier Proteins / Q000096:biosynthesis*; D002460:Cell Line; D017077:Culture Media, Conditioned; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000276:immunology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D037102:Lectins; D007948:Leukemia, Monocytic, Acute; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology*; D008565:Membrane Proteins / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis; D014158:Transcription, Genetic / Q000187:drug effects / Q000276:immunology; D014407:Tumor Cells, Cultured
D058927:5-Lipoxygenase-Activating Proteins; C548592:ALOX5AP protein, human; D002352:Carrier Proteins; D017077:Culture Media, Conditioned; D007377:Interleukin-3; D037102:Lectins; D008565:Membrane Proteins; D012333:RNA, Messenger; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D001094:Arachidonate 5-Lipoxygenase