Identification of a novel dexamethasone-sensitive RNA-destabilizing region on rat monocyte chemoattractant protein 1 mRNA.
Glucocorticoids are potent anti-inflammatory agents widely used in the treatment of human disease. We have previously shown that the inflammatory cytokine monocyte chemoattractant protein 1 (MCP-1) is regulated posttranscriptionally by glucocorticoids in arterial smooth muscle cells (SMC). To elucidate the mechanism mediating this effect, in vitro-transcribed radiolabeled MCP-1 mRNA was incubated with cytoplasmic extracts from SMC and analyzed by gel electrophoresis. Extracts from SMC treated with platelet-derived growth factor (PDGF) did not degrade the transcripts for up to 3 h. In contrast, extracts from cells treated with 1 microM dexamethasone (Dex) alone or in combination with PDGF degraded the probe with a half-life of approximately 15 min. Dex had maximal effect at concentrations above 0.01 microM and was effective on both rat and human MCP-1 transcripts. By deletion analysis, the Dex-sensitive region of the MCP-1 mRNA was localized to the initial 224 nucleotides (nt) at the 5' end and did not involve an AU-rich sequence in the 3' untranslated end. The 224-nt region conferred Dex sensitivity to heterologous mRNA. These studies provide new insights into the molecular mechanisms underlying the effect of glucocorticoids on gene expression.
Poon
M
M
The Zena and Michael A. Wiener Cardiovascular Institute and Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA. m_poon@smt-plink.mssm.edu
Liu
B
B
Taubman
M B
MB
D000818:Animals; D018932:Chemokine CCL2 / Q000235:genetics*; D003907:Dexamethasone / Q000494:pharmacology*; D004347:Drug Interactions; D005938:Glucocorticoids / Q000494:pharmacology*; D006207:Half-Life; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D020871:RNA Stability / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017384:Sequence Deletion; D013347:Subcellular Fractions / Q000378:metabolism
D018932:Chemokine CCL2; D005938:Glucocorticoids; D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; D003907:Dexamethasone