title: Involvement of S1P1 receptor pathway in angiogenic effects of a novel adenosine-like nucleic acid analog COA-Cl in cultured human vascular endothelial cells.
abstract: COA-Cl (2Cl-C.OXT-A) is a recently developed adenosine-like nucleic acid analog that promotes angiogenesis via the mitogen-activated protein (MAP) kinases ERK1/2. Endothelial S1P1 receptor plays indispensable roles in developmental angiogenesis. In this study, we examined the functions of S1P1 in COA-Cl-induced angiogenic responses. Antagonists for S1P1, W146, and VPC23019, substantially but still partly inhibited the effects of COA-Cl with regard to ERK1/2 activation and tube formation in cultured human umbilical vein endothelial cells (HUVEC). Antagonists for adenosine A1 receptor and purinergic P2Y1 receptor were without effect. Genetic knockdown of S1P1 with siRNA, but not that of S1P3, attenuated COA-Cl-elicited ERK1/2 responses. The signaling properties of COA-Cl showed significant similarities to those of sphingosine 1-phosphate, an endogenous S1P1 ligand, in that both induced responses sensitive to pertussis toxin (Gα i/o inhibitor), 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxymethyl ester) (BAPTA-AM), (calcium chelator), and PP2 (c-Src tyrosine kinase inhibitor). COA-Cl elevated intracellular Ca(2+) concentration and induced tyrosine phosphorylation of p130Cas, a substrate of c-Src, in HUVEC. COA-Cl displaced [(3)H]S1P in a radioligand-binding competition assay in chem-1 cells overexpressing S1P1. However, COA-Cl activated ERK1/2 in CHO-K1 cells that lack functional S1P1 receptor, suggesting the presence of additional yet-to-be-defined COA-Cl target in these cells. The results thus suggest the major contribution of S1P1 in the angiogenic effects of COA-Cl. However, other mechanism such as that seen in CHO-K1 cells may also be partly involved. Collectively, these findings may lead to refinement of the design of this nucleic acid analog and ultimately to development of small molecule-based therapeutic angiogenesis.
authors.affiliation: Department of Cardiovascular Physiology, Faculty of Medicine, Kagawa University 1750-1 Ikenobe, Miki-Cho, Kita-Gun, Kagawa, 761-0793, Japan.
authors.forename: Junsuke
authors.initials: J
authors.lastname: Igarashi
authors.affiliation: Department of Cardiovascular Physiology, Faculty of Medicine, Kagawa University 1750-1 Ikenobe, Miki-Cho, Kita-Gun, Kagawa, 761-0793, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hashimoto
authors.affiliation: Department of Dermatology, Faculty of Medicine, Kagawa University 1750-1 Ikenobe, Miki-Cho, Kita-Gun, Kagawa, 761-0793, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kubota
authors.affiliation: Department of Dermatology, Faculty of Medicine, Kagawa University 1750-1 Ikenobe, Miki-Cho, Kita-Gun, Kagawa, 761-0793, Japan.
authors.forename: Kazuyo
authors.initials: K
authors.lastname: Shoji
authors.affiliation: Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University 1314-1 Shido, Sanuki, Kagawa, 769-2193, Japan.
authors.forename: Tokumi
authors.initials: T
authors.lastname: Maruyama
authors.affiliation: Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University 1314-1 Shido, Sanuki, Kagawa, 769-2193, Japan.
authors.forename: Norikazu
authors.initials: N
authors.lastname: Sakakibara
authors.affiliation: Department of Cardiovascular Physiology, Kanazawa University School of Medicine 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8640, Japan.
authors.forename: Yoh
authors.initials: Y
authors.lastname: Takuwa
authors.affiliation: Department of Physiology, Kawasaki Medical School 577 Matsushima, Kurashiki, 701-0192, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ujihara
authors.affiliation: Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Shitada-Cho 2-5-1, Kita-Ku, Okayama, 700-0914, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Katanosaka
authors.affiliation: Department of Physiology, Kawasaki Medical School 577 Matsushima, Kurashiki, 701-0192, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Mohri
authors.affiliation: Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Shitada-Cho 2-5-1, Kita-Ku, Okayama, 700-0914, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Naruse
authors.affiliation: Department of Cardiovascular Physiology, Faculty of Medicine, Kagawa University 1750-1 Ikenobe, Miki-Cho, Kita-Gun, Kagawa, 761-0793, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Yamashita
authors.affiliation: Department of Cardiovascular Physiology, Faculty of Medicine, Kagawa University 1750-1 Ikenobe, Miki-Cho, Kita-Gun, Kagawa, 761-0793, Japan.
authors.forename: Ryuji
authors.initials: R
authors.lastname: Okamoto
authors.affiliation: Department of Cardiovascular Physiology, Faculty of Medicine, Kagawa University 1750-1 Ikenobe, Miki-Cho, Kita-Gun, Kagawa, 761-0793, Japan.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Hirano
authors.affiliation: Department of Cardiovascular Physiology, Faculty of Medicine, Kagawa University 1750-1 Ikenobe, Miki-Cho, Kita-Gun, Kagawa, 761-0793, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kosaka
authors.affiliation: Department of Pharmaco-Bio-Informatics, Faculty of Medicine, Kagawa University 1750-1 Ikenobe, Miki-Cho, Kita-Gun, Kagawa, 761-0793, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Takata
authors.affiliation: Department of Pharmaco-Bio-Informatics, Faculty of Medicine, Kagawa University 1750-1 Ikenobe, Miki-Cho, Kita-Gun, Kagawa, 761-0793, Japan.
authors.forename: Ryoji
authors.initials: R
authors.lastname: Konishi
authors.affiliation: Department of Pharmaco-Bio-Informatics, Faculty of Medicine, Kagawa University 1750-1 Ikenobe, Miki-Cho, Kita-Gun, Kagawa, 761-0793, Japan.
authors.forename: Ikuko
authors.initials: I
authors.lastname: Tsukamoto
keywords: Angiogenesis; S1P1 receptors; endothelial cells; nucleic acid; receptors; signal transduction; sphingosine 1-phosphate