- Home
- Genomes
- Genome Browser
- Tools
- Mirrors
- Downloads
- My Data
- Projects
- Help
- About Us
OBJECTIVE
Low density lipoproteins (LDLs) modulate the expression of key genes involved in atherogenesis. Recently, we have shown that the transcription factor neuron-derived orphan receptor-1 (NOR-1) is involved in vascular smooth muscle cell (VSMC) proliferation. Our aim was to analyze whether NOR-1 is involved in LDL-induced mitogenic effects in VSMC.RESULTS
LDL induced NOR-1 expression in a time- and dose-dependent manner. Antisense oligonucleotides against NOR-1 inhibit DNA synthesis induced by LDL in VSMCs as efficiently as antisense against the protooncogene c-fos. The upregulation of NOR-1 mRNA levels by LDL involves pertusis-sensitive G protein-coupled receptors, Ca2+ mobilization, protein kinases A (PKA) and C (PKC) activation, and mitogen-activated protein kinase pathways (MAPK) (p44/p42 and p38). LDL promotes cAMP response element binding protein (CREB) activation (phosphorylation in Ser133). In transfection assays a dominant-negative of CREB inhibits NOR-1 promoter activity, while mutation of specific (cAMP response element) CRE sites in the NOR-1 promoter abolishes LDL-induced NOR-1 promoter activity.CONCLUSIONS
In VSMCs, LDL-induced mitogenesis involves NOR-1 upregulation through a CREB-dependent mechanism. CREB could play a role in the modulation by LDL of key genes (containing CRE sites) involved in atherogenesis.
protein kinases A (PKA) → p44/p42: " The upregulation of NOR-1 mRNA levels by LDL involves pertusis-sensitive G protein coupled receptors, Ca2+ mobilization, protein kinases A (PKA) and C ( PKC ) activation , and mitogen activated protein kinase pathways ( MAPK ) ( p44/p42 and p38 ) "
protein kinases A (PKA) → p38: " The upregulation of NOR-1 mRNA levels by LDL involves pertusis-sensitive G protein coupled receptors, Ca2+ mobilization, protein kinases A (PKA) and C ( PKC ) activation , and mitogen activated protein kinase pathways ( MAPK ) ( p44/p42 and p38 ) "
CREB → LDL: " LDL promotes cAMP response element binding protein ( CREB ) activation ( phosphorylation in Ser133 ) "