title: Enhancement of angiogenesis through stabilization of hypoxia-inducible factor-1 by silencing prolyl hydroxylase domain-2 gene.
abstract: Hypoxia-inducible factor-1 (HIF-1) plays a central role in cellular response to hypoxia by activating vascular endothelial growth factor (VEGF) and other angiogenic factors. Prolyl hydroxylase domain-2 (PHD2) protein induces the degradation of HIF-1 by hydroxylating specific prolyl residues. Therefore gene silencing of PHD2 by RNA interference (RNAi) might increase the expression of angiogenic growth factors and, consequently, neoangiogenesis through the stabilization of HIF-1alpha. In this study we have shown that the specific silencing of PHD2 is sufficient for stabilizing HIF-1alpha and increasing its transcriptional activity, resulting in the increased expression of angiogenic factors including VEGF and fibroblast growth factor-2 (FGF2). Moreover, when PHD2-siRNA vector was used, the increase in VEGF secretion was observed for as long as 18 days after transfection. In vitro treatment of human umbilical vein endothelical cells with conditioned medium from PHD2-siRNA vector-transfected NIH3T3 cells was shown to increase cell proliferation. Also, in vivo angiogenesis was observed in mice implanted with Matrigel plugs mixed with NIH3T3 cells transfected with PHD2-siRNA vector. These results indicate that PHD2 silencing induces expressions of multiple angiogenic growth factors by stabilizing HIF-1alpha, and that the implantation of cells transfected with PHD2-siRNA vector is sufficient to enhance angiogenesis in vivo. In the light of these findings, PHD2 silencing by RNAi might offer a potential tool for angiogenic therapy.
authors.affiliation: Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Shourong
authors.initials: S
authors.lastname: Wu
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Nishiyama
authors.forename: Mitsunobu R
authors.initials: MR
authors.lastname: Kano
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Morishita
authors.forename: Kohei
authors.initials: K
authors.lastname: Miyazono
authors.forename: Keiji
authors.initials: K
authors.lastname: Itaka
authors.forename: Ung-Il
authors.initials: UI
authors.lastname: Chung
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kataoka
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation; D015316:Genetic Therapy; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases; D017874:Immediate-Early Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D041681:NIH 3T3 Cells; D018919:Neovascularization, Physiologic / Q000235:genetics; D011393:Procollagen-Proline Dioxygenase; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D017874:Immediate-Early Proteins; D034741:RNA, Small Interfering; D042461:Vascular Endothelial Growth Factor A; D011393:Procollagen-Proline Dioxygenase; C490189:Egln1 protein, mouse; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases