title: VEGF165b Modulates Endothelial VEGFR1-STAT3 Signaling Pathway and Angiogenesis in Human and Experimental Peripheral Arterial Disease.
abstract: BACKGROUND
  Atherosclerotic-arterial occlusions decrease tissue perfusion causing ischemia to lower limbs in patients with peripheral arterial disease (PAD). Ischemia in muscle induces an angiogenic response, but the magnitude of this response is frequently inadequate to meet tissue perfusion requirements. Alternate splicing in the exon-8 of vascular endothelial growth factor (VEGF)-A results in production of proangiogenic VEGFxxxa isoforms (VEGF165a, 165 for the 165 amino acid product) and antiangiogenic VEGFxxxb (VEGF165b) isoforms.
  
  
  OBJECTIVE
  The antiangiogenic VEGFxxxb isoforms are thought to antagonize VEGFxxxa isoforms and decrease activation of VEGF receptor-2 (VEGFR2), hereunto considered the dominant receptor in postnatal angiogenesis in PAD. Our data will show that VEGF165b inhibits VEGFR1 signal transducer and activator of transcription (STAT)-3 signaling to decrease angiogenesis in human and experimental PAD.
  
  
  RESULTS
  In human PAD versus control muscle biopsies, VEGF165b: (1) is elevated, (2) is bound higher (versus VEGF165a) to VEGFR1 not VEGFR2, and (3) levels correlated with decreased VEGFR1, not VEGFR2, activation. In experimental PAD, delivery of an isoform-specific monoclonal antibody to VEGF165b versus control antibody enhanced perfusion in animal model of severe PAD (Balb/c strain) without activating VEGFR2 signaling but with increased VEGFR1 activation. Receptor pull-down experiments demonstrate that VEGF165b inhibition versus control increased VEGFR1-STAT3 binding and STAT3 activation, independent of Janus-activated kinase-1)/Janus-activated kinase-2. Using VEGFR1+/-mice that could not increase VEGFR1 after ischemia, we confirm that VEGF165b decreases VEGFR1-STAT3 signaling to decrease perfusion.
  
  
  CONCLUSIONS
  Our results indicate that VEGF165b prevents activation of VEGFR1-STAT3 signaling by VEGF165a and hence inhibits angiogenesis and perfusion recovery in PAD muscle.
authors.affiliation: From the Cardiovascular Research Center (V.C.G., M.C., B.H.A.), Department of Biology (A.K.), and Department of Cardiovascular Medicine, University of Virginia, Charlottesville (B.H.A.).
authors.forename: Vijay Chaitanya
authors.initials: VC
authors.lastname: Ganta
authors.affiliation: From the Cardiovascular Research Center (V.C.G., M.C., B.H.A.), Department of Biology (A.K.), and Department of Cardiovascular Medicine, University of Virginia, Charlottesville (B.H.A.).
authors.forename: Min
authors.initials: M
authors.lastname: Choi
authors.affiliation: From the Cardiovascular Research Center (V.C.G., M.C., B.H.A.), Department of Biology (A.K.), and Department of Cardiovascular Medicine, University of Virginia, Charlottesville (B.H.A.).
authors.forename: Anna
authors.initials: A
authors.lastname: Kutateladze
authors.affiliation: From the Cardiovascular Research Center (V.C.G., M.C., B.H.A.), Department of Biology (A.K.), and Department of Cardiovascular Medicine, University of Virginia, Charlottesville (B.H.A.). annex@virginia.edu.
authors.forename: Brian H
authors.initials: BH
authors.lastname: Annex
mesh_terms: D000818:Animals; D015331:Cohort Studies; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000473:pathology; D005260:Female; D057809:HEK293 Cells; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D057507:Mice, 129 Strain; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D009389:Neovascularization, Pathologic / Q000188:drug therapy / Q000378:metabolism*; D058729:Peripheral Arterial Disease / Q000188:drug therapy / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000008:administration & dosage / Q000378:metabolism*; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000378:metabolism*
chemical_list: D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1
keywords: alternative splicing; amputation; anti-angiogenic VEGF-A isoforms; ischemia; peripheral artery disease