In:
FEBS Letters, Wiley, Vol. 457, No. 2 ( 1999-08-27), p. 241-245
Abstract:
Lysophosphatidylcholine (lyso‐PC), a polar phospholipid increased in atherogenic lipoproteins and atherosclerotic lesions, has been shown to induce transcription of a variety of endothelial genes relevant to atherogenesis. Lyso‐PC has been shown to activate c‐jun N‐terminal kinase (JNK) and activator protein 1 (AP‐1) and thereby stimulate transcription of the c‐jun gene. Here we provide evidence that lyso‐PC can phosphorylate cyclic AMP responsive element binding protein (CREB) and thereby activate the jun2 12‐ O ‐tetradecanoylphorbol 13‐acetate response element (jun2TRE) site of the c‐jun promoter, which appears to be the major molecular mechanism involved in lyso‐PC‐induced c‐jun gene expression in cultured bovine aortic endothelial cells (BAEC). Transient transfection of BAEC with a 1.6‐kbp c‐jun promoter and luciferase reporter fusion gene resulted in a 12.9‐fold increase in luciferase activity by lyso‐PC treatment. Serial deletion mutation in c‐jun promoter and luciferase reporter gene assay revealed that the 5′ promoter region between nucleotide numbers −268 and −127, which contains a jun2TRE binding sequence, was most crucial for lyso‐PC‐induced transcription. The 5′ promoter region between −76 and −27, which contains an AP‐1 site, also affected lyso‐PC‐induced transcription of the c‐jun gene. Point mutation in the jun2TRE site reduced lyso‐PC‐induced transcription of the c‐jun promoter‐luciferase fusion gene by a 70.3% decrease in c‐jun promoter activity. Electrophoretic mobility shift assays showed increased binding of 32 P‐labeled oligonucleotides with jun2TRE in nuclear extracts isolated from lyso‐PC‐treated BAEC, which was abolished or supershifted by anti‐CREB antibody. Immunoblotting with anti‐phosphorylated CREB antibody showed rapid phosphorylation of this protein after lyso‐PC treatment. These results indicate that lyso‐PC phosphorylates CREB, which was then bound to the jun2TRE site of the c‐jun promoter and activated transcription. Activation of jun2TRE may play a key role in the transcriptional activation of c‐jun as well as other endothelial genes depending upon these transcription factors.
Type of Medium:
Online Resource
ISSN:
0014-5793
,
1873-3468
DOI:
10.1016/S0014-5793(99)01049-2
Language:
English
Publisher:
Wiley
Publication Date:
1999
detail.hit.zdb_id:
1460391-3
SSG:
12
Permalink