Post-transcriptional regulation of TNF-alpha during in vitro differentiation of human monocytes/macrophages in primary culture.
Tumor necrosis factor alpha (TNF-alpha), a proinflammatory cytokine, is produced abundantly by monocytes and macrophages. We have compared LPS-stimulated TNF-alpha production and regulation in freshly isolated human monocytes and macrophages differentiated in vitro. A significant increase in LPS-induced TNF-alpha protein secretion was observed in macrophages over freshly isolated monocytes without comparable differences in TNF-alpha mRNA induction. Polysome gradient analysis showed polysome-mRNA distribution did not change, whereas TNF-alpha mRNA stability increased in macrophages. Tristetraprolin mRNA expression was constitutive and decreased with differentiation-linked kinetics. Blockable LPS-inducible MAP kinase activity (p38, ERK) affected TNF-alpha biosynthesis differentially at the transcriptional and post-transcriptional level throughout the culture period. We suggest that the increase in TNF-alpha secretion in macrophages relates to changes in post-transcriptional processing, which is regulated indirectly by the expression of RNA-binding proteins. Changes in gene expression throughout monocytic differentiation equip the cell to act as a more potent producer of this proinflammatory cytokine.
MacKenzie
Simon
S
Dept. de Fisiologia, Facultat de Biologia, Universitat de Barcelona, Spain. Simon.MacKenzie@uab.es
Fernàndez-Troy
Neus
N
Espel
Enric
E
D018929:Cell Culture Techniques / Q000379:methods; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology*; D006801:Humans; D016130:Immunophenotyping; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008262:Macrophage Activation; D008264:Macrophages / Q000166:cytology* / Q000187:drug effects / Q000276:immunology; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics; D009000:Monocytes / Q000166:cytology* / Q000187:drug effects / Q000276:immunology; D011132:Polyribosomes / Q000378:metabolism / Q000648:ultrastructure; D012323:RNA Processing, Post-Transcriptional / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*; D048051:p38 Mitogen-Activated Protein Kinases
D008070:Lipopolysaccharides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases