Endothelin-1 was initially identified as a 21-residue potent vasoconstrictor peptide produced by vascular endothelial cells, but was subsequently found to have many effects on both vascular and non-vascular tissues. The discovery of three isopeptides of the endothelin family, ET-1, ET-2 and ET-3, each possessing a diverse set of pharmacological activities of different potency, suggested the existence of several different endothelin receptor subtypes. Endothelins may elicit biological responses by various signal-transduction mechanisms, including the G protein-coupled activation of phospholipase C and the activation of voltage-dependent Ca2+ channels. Thus, different subtypes of the endothelin receptor may use different signal-transduction mechanisms. Here we report the cloning of a complementary DNA encoding one subtype belonging to the superfamily of G protein-coupled receptors. COS-7 cells transfected with the cDNA express specific and high-affinity binding sites for endothelins, responding to binding by the production of inositol phosphates and a transient increase in the concentration of intracellular free Ca2+. The three endothelin isopeptides are roughly equipotent in displacing 125I-labelled ET-1 binding and causing Ca2+ mobilization. A messenger RNA corresponding to the cDNA is detected in many rat tissues including the brain, kidney and lung but not in vascular smooth muscle cells. These results indicate that this cDNA encodes a 'nonselective' subtype of the receptor which is different from the vascular smooth muscle receptor.

Objective-We investigated the comparative roles of mitogen-activated protein (MAP) kinases, including c-Jun NH2-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38, in vascular smooth muscle cell (VSMC) proliferation, migration, and gene expression. Methods and Results-VSMCs were infected with recombinant adenovirus containing dominant-negative mutants of ERK, p38, and JNK (Ad-DN-ERK, Ad-DN-p38, and Ad-DN-JNK, respectively) to specifically inhibit the respective MAP kinases and then stimulated with platelet-derived growth factor (PDGF)-BB. Ad-DN-ERK attenuated PDGF-BB-induced VSMC proliferation more potently than Ad-DN-p38 or Ad-DN-JNK, indicating the dominant role of ERK in VSMC proliferation. Ad-DN-ERK, Ad-DN-p38, and Ad-DN-JNK similarly inhibited PDGF-induced VSMC migration. Ad-DN-ERK and Ad-DN-JNK suppressed PDGF-BB-induced downregulation of cyclin-dependent kinase inhibitor p27 Kip1 , whereas Ad-DN-p38 decreased PDGF-BB-induced upregulation of p21 Cip1 . Ad-DN-ERK inhibited PDGF-BB-induced plasminogen activator inhibitor type-1 (PAI-1), monocyte chemoattractant protein-1, and transforming growth factor-␤ 1 expressions, Ad-DN-p38 blocked monocyte chemoattractant protein-1 and transforming growth factor-␤ 1 expression but not PAI-1, whereas Ad-DN-JNK suppressed only PAI-1 expression. Moreover, in vivo gene transfer of Ad-DN-p38 to rat carotid artery caused the inhibition of intimal hyperplasia by balloon injury, indicating the involvement of p38 in vascular remodeling in vivo. Key Words: platelet-derived growth factor Ⅲ gene transfer Ⅲ vascular smooth muscle cell Ⅲ proliferation Ⅲ gene expression P latelet-derived growth factor-BB (PDGF-BB) is one of the most potent mitogens and chemoattractants for vascular smooth muscle cells (SMCs) and plays the central role in the onset and development of various vascular disorders. [1][2][3][4][5][6] As reviewed, 7,8 PDGF-BB, through interaction with PDGF, activates multiple signaling pathways in vascular SMCs, including SHP-2, Src, PLC-␥, Ras, protein kinase A, phosphatidylinositol 3-kinase (PI3-kinase), and mitogen-activated protein (MAP) kinases, which are supposed to play some role in PDGF-induced cellular responses. Ras, 9 Src, 10 and c-Jun 11 contribute to PDGFinduced vascular SMC proliferation. On the other hand, PI 3-kinase is known to participate in PDGF-induced vascular SMC migration. 12 However, the molecular mechanism of vascular SMC proliferation and migration by PDGF-BB remains to be fully understood. PDGF-BB not only stimulates proliferation and migration in vascular SMCs but also induces various genes. Interestingly, previous reports indicate that PDGF-BB induces plasminogen activator inhibitor type-1 (PAI-1), monocyte chemoattractant protein-1 (MCP-1), and transforming growth factor-␤ 1 (TGF-␤ 1 ) in vascular SMCs. [13][14][15] Increased PAI-1 that leads to inhibition of plasminogen activation impairs fibrinolysis and thereby promotes thrombosis. 16 MCP-1 is the major chemotactic factor involved in the migration of monocytes into...

We report the formation of a bilayer Bi(111) ultrathin film, which is theoretically predicted to be in a two-dimensional quantum spin Hall state, on a Bi(2)Te(3) substrate. From angle-resolved photoemission spectroscopy measurements and ab initio calculations, the electronic structure of the system can be understood as an overlap of the band dispersions of bilayer Bi and Bi(2)Te(3). Our results show that the Dirac cone is actually robust against nonmagnetic perturbations and imply a unique situation where the topologically protected one- and two-dimensional edge states are coexisting at the surface.

Background/Aim: Indoxyl sulfate, a uremic toxin, is considered a risk factor for cardiovascular disease (CVD) in chronic kidney disease (CKD). The present study aimed to determine whether indoxyl sulfate increases the expression of intercellular adhesion molecule-1 (ICAM-1) and monocyte chemotactic protein-1 (MCP-1) by reactive oxygen species (ROS)-induced activation of nuclear factor-ĸB (NF-ĸB) in vascular endothelial cells. Methods: Human umbilical vein endothelial cells (HUVEC) were incubated with indoxyl sulfate. The expression of ICAM-1 and MCP-1 in HUVEC was analyzed by quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. Phospho-NF-ĸB p65 (Ser 536), an active form of the NF-ĸB subunit, was determined by Western blotting. Results: Indoxyl sulfate significantly increased the mRNA expression of ICAM-1 and MCP-1 in HUVEC in a time- and concentration-dependent manner. Inhibitors of NF-ĸB (ammonium pyrrolidinedithiocarbamate and isohelenin) and an antioxidant (N-acetyl-L-cysteine) suppressed the indoxyl sulfate-induced expression of ICAM-1 and MCP-1 in HUVEC. Indoxyl sulfate increased phospho- NF-ĸB p65 in HUVEC, and N-acetyl-L-cysteine suppressed it. Conclusions: Indoxyl sulfate upregulates the expression of ICAM-1 and MCP-1 by ROS-induced activation of NF-ĸB in vascular endothelial cells. Thus, indoxyl sulfate may play an important role in the development of CVD in CKD by increasing the endothelial expression of ICAM-1 and MCP-1.