Y-Box Binding Protein-1 Controls CC Chemokine Ligand-5 (CCL5) Expression in Smooth Muscle Cells and Contributes to Neointima Formation in Atherosclerosis-Prone Mice

Abstract

Background-The CC chemokine CCL5/Regulated on Activation, Normal T Cell Expressed and Secreted (RANTES) is upregulated in mononuclear cells or deposited by activated platelets during inflammation and has been implicated in atherosclerosis and neointimal hyperplasia. We investigated the influence of the transcriptional regulator Y-box binding protein (YB)-1 on CCL5 expression and wire-induced neointimal hyperplasia. Methods and Results-Analysis of the CCL5 promoter revealed potential binding sites for YB-1, and interaction of YB-1 with a sequence at position Ϫ204/Ϫ173 was confirmed by DNA binding assays. Both YB-1 expression and CC chemokine ligand-5 (CCL5) mRNA expression were increased in neointimal versus medial smooth muscle cells, as analyzed by real-time polymerase chain reaction. Overexpression of YB-1 in smooth muscle cells (but not macrophages) enhanced CCL5 transcriptional activity in reporter assays, mRNA and protein expression, and CCL5-mediated monocyte arrest. Carotid arteries of hyperlipidemic apolipoprotein E-deficient mice were subjected to intraluminal transfection with a lentivirus encoding YB-1 short hairpin RNA or empty vector directly after wire injury. Double immunofluorescence revealed YB-1 expression in neointimal smooth muscle cells but not macrophages and colocalization with neointimal CCL5, which was downregulated by YB-1 short hairpin RNA. Neointima formation was decreased significantly after YB-1 knockdown compared with controls and was associated with a diminished content of lesional macrophages. A reduction of lesion formation by YB-1 knockdown was not observed in apolipoprotein E-deficient mice deficient in the CCL5 receptor CCR5 or after treatment with the CCL5 antagonist Met-RANTES, which indicates that YB-1 effects were dependent on CCL5. Conclusions-The transcriptional regulator YB-1 mediates CCL5 expression in smooth muscle cells and thereby contributes to neointimal hyperplasia, thus representing a novel target with which to limit vascular remodeling.

Retinoic Acid Receptor α Mediates All-trans-retinoic Acid-induced Klf4 Gene Expression by Regulating Klf4 Promoter Activity in Vascular Smooth Muscle Cells

“…Knockdown of endogenous YB1 led to a significant decrease of RAR␣ occupancy in the Klf4 promoter in ATRA-stimulated VSMCs. YB1 transactivates CC chemokine ligand 5 gene transcription by binding to the CCAAT box on the chemokine ligand 5 promoter in VSMCs and contributes to neointimal hyperplasia (45). This implicates YB1 as a critical factor in the regulation of the differentiation and proliferation of VSMCs, and our findings further suggest that YB1 may serve as a key mediator of VSMC differentiation.…”

Sphingosine Kinase 1 Regulates Tumor Necrosis Factor-mediated RANTES Induction through p38 Mitogen-activated Protein Kinase but Independently of Nuclear Factor κB Activation

“…Finally, it is a distinct possibility that multiple sphingolipids can regulate RANTES induction through distinct mechanisms. Clearly, given the importance of RANTES in physiological inflammation, and its role in a variety of pathologies (21)(22)(23)(24)(25)(26)(27), further research in this area could yield a number of potential therapeutic targets.…”

Y-Box Binding Protein 1 and RNase UK114 Mediate Monocyte Chemoattractant Protein 1 mRNA Stability in Vascular Smooth Muscle Cells

“…Rat aortic SMCs were isolated from the thoracic aortas of male Sprague-Dawley rats by enzymatic dissociation and cultured in Dulbecco modified Eagle medium (DMEM; Gibco Laboratories, Gaithersburg, MD) and 10% heat-inactivated bovine serum as described previously (4). The response to Dex has been consistently seen with cells as early as passage 5 and as late as passage 23 (26); passages 12 to 18 were used for all experiments. YB-1, UK, and protein kinase C␦ (PKC␦) small interfering RNAs (siRNAs) were purchased from IDT (Coralville, IA).…”