Cell type-specific regulation of angiogenic growth factor gene expression and induction of angiogenesis in nonischemic tissue by a constitutively active form of hypoxia-inducible factor 1
CIRCULATION RESEARCH
Authors: Kelly, BD; Hackett, SF; Hirota, K; Oshima, Y; Cai, ZQ; Berg-Dixon, S; Rowan, A; Yan, ZJ; Campochiaro, PA; Semenza, GL
Abstract
Understanding molecular mechanisms regulating angiogenesis may lead to novel therapies for ischemic disorders. Hypoxia-inducible factor 1 ( HIF-1) activates vascular endothelial growth factor ( VEGF) gene expression in hypoxic/ischemic tissue. In this study we demonstrate that exposure of primary cultures of cardiac and vascular cells to hypoxia or AdCA5, an adenovirus encoding a constitutively active form of HIF-1alpha, modulates the expression of genes encoding the angiogenic factors angiopoietin-1 (ANGPT1), ANGPT2, placental growth factor, and platelet-derived growth factor-B. Loss-of-function effects were also observed in HIF-1alpha-null embryonic stem cells. Depending on the cell type, expression of ANGPT1 and ANGPT2 was either activated or repressed in response to hypoxia or AdCA5. In all cases, there was complete concordance between the effects of hypoxia and AdCA5. Injection of AdCA5 into mouse eyes induced neovascularization in multiple capillary beds, including those not responsive to VEGF alone. Analysis of gene expression revealed increased expression of ANGPT1, ANGPT2, platelet-derived growth factor-B, placental growth factor, and VEGF mRNA in AdCA5-injected eyes. These results indicate that HIF-1 functions as a master regulator of angiogenesis by controlling the expression of multiple angiogenic growth factors and that adenovirus-mediated expression of a constitutively active form of HIF-1alpha is sufficient to induce angiogenesis in nonischemic tissue of an adult animal.
Concurrent manifestation of oligodontia and thrombocytopenia caused by a contiguous gene deletion in 12p13.2: A three-generation clinical report
MOLECULAR GENETICS & GENOMIC MEDICINE
Authors: Ross, Jamila; Fennis, Willem; de Leeuw, Nicole; Cune, Marco; Willemze, Annemieke; Rosenberg, Antoine; Van Amstel, Hans-Kristian Ploos; Creton, Marijn; van den Boogaard, Marie-Jose
Abstract
BackgroundWnt and Wnt-associated pathways play an important role in the genetic etiology of oligodontia, a severe form of tooth agenesis. Loss-of-function mutations in LRP6 , encoding a transmembrane cell-surface protein that functions as a coreceptor in the canonical Wnt/b-catenin signaling cascade, also contribute to genetic oligodontia. Methods and resultsWe describe a three-generation family with hereditary thrombocytopenia and oligodontia. Genome wide array analysis was performed. The array results from the index patient revealed an interstitial loss of 150kb in 8p23.1 (chr8:6,270,299-6,422,558; hg19) encompassing MCPH1 and ANGPT2 and an interstitial loss of 290kb in 12p13.2 (chr12:12,005,720-12,295,290; hg19) encompassing ETV6, BCL2L14 and LRP6. ConclusionThis case report shows a three-generation family with hereditary thrombocytopenia and oligodontia with a heterozygous 290kb novel contiguous gene deletion in band p13.2 of chromosome 12, encompassing LRP6 and ETV6. In this report we discuss the clinical relevance of the deletion of both genes and illustrate the importance of thorough examination of oligodontia patients. Comprising not only the oral status but also the medical history of the patients and their relatives.