title: PDE4 regulates tissue plasminogen activator expression of human brain microvascular endothelial cells.
abstract: BACKGROUND
  Factors regulating brain tissue plasminogen activator (tPA) are pertinent for stroke. Recent observations have suggested a role for the phosphodiesterase-4 (PDE4) pathway in stroke pathogenesis, via an uncertain mechanism. We studied PDE4 regulation of tPA expression by human brain microvascular endothelial cells in a variety of conditions, including an in vitro model of ischemia.
  
  
  METHODS
  We analyzed tPA antigen and mRNA of human brain microvascular endothelial cells (HBECs) during normoxia and oxygen-glucose deprivation (OGD) following inhibition of PDE4 and PDE4D, using HBEC monocultures and co-cultures with astrocytes and pericytes, and analyzed relevant signal transduction pathways.
  
  
  RESULTS
  PDE4 inhibitor rolipram enhanced OGD effects on endothelial tPA release in endothelial monocultures and co-cultures with astrocytes; there was a 54±10% (p<0.001) reduction of tPA release in astrocyte-endothelial co-cultures under OGD. PDE4D siRNA reduced endothelial tPA mRNA to 40-55% of control (p<0.05). Use of Epac inducer mimicked, while use of Epac siRNA inhibited, these effects.
  
  
  CONCLUSIONS
  Inhibition of PDE4 and PDE4D reduced expression of tPA by HBEC via Epac pathway.
authors.affiliation: Department of Anatomy & Neurobiology, University of California, Irvine, USA.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Shuo
authors.initials: S
authors.lastname: Liu
authors.forename: Chuanhui
authors.initials: C
authors.lastname: Yu
authors.forename: Shur-Jen
authors.initials: SJ
authors.lastname: Wang
authors.forename: Annlia
authors.initials: A
authors.lastname: Paganini-Hill
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Fisher
mesh_terms: D001921:Brain / Q000098:blood supply* / Q000378:metabolism; D018929:Cell Culture Techniques; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4 / Q000378:metabolism*; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D006801:Humans; D008833:Microcirculation; D058988:Phosphodiesterase 4 Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020889:Rolipram / Q000378:metabolism / Q000494:pharmacology; D015398:Signal Transduction; D010959:Tissue Plasminogen Activator / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D014162:Transfection
chemical_list: D058988:Phosphodiesterase 4 Inhibitors; D012333:RNA, Messenger; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D010959:Tissue Plasminogen Activator; D020889:Rolipram