title: S100A1 deficiency impairs postischemic angiogenesis via compromised proangiogenic endothelial cell function and nitric oxide synthase regulation.
abstract: BACKGROUND
  Mice lacking the EF-hand Ca2+ sensor S100A1 display endothelial dysfunction because of distorted Ca2+ -activated nitric oxide (NO) generation.
  
  
  OBJECTIVE
  To determine the pathophysiological role of S100A1 in endothelial cell (EC) function in experimental ischemic revascularization.
  
  
  RESULTS
  Patients with chronic critical limb ischemia showed almost complete loss of S100A1 expression in hypoxic tissue. Ensuing studies in S100A1 knockout (SKO) mice subjected to femoral artery resection unveiled insufficient perfusion recovery and high rates of autoamputation. Defective in vivo angiogenesis prompted cellular studies in SKO ECs and human ECs, with small interfering RNA-mediated S100A1 knockdown demonstrating impaired in vitro and in vivo proangiogenic properties (proliferation, migration, tube formation) and attenuated vascular endothelial growth factor (VEGF)-stimulated and hypoxia-stimulated endothelial NO synthase (eNOS) activity. Mechanistically, S100A1 deficiency compromised eNOS activity in ECs by interrupted stimulatory S100A1/eNOS interaction and protein kinase C hyperactivation that resulted in inhibitory eNOS phosphorylation and enhanced VEGF receptor-2 degradation with attenuated VEGF signaling. Ischemic SKO tissue recapitulated the same molecular abnormalities with insufficient in vivo NO generation. Unresolved ischemia entailed excessive VEGF accumulation in SKO mice with aggravated VEGF receptor-2 degradation and blunted in vivo signaling through the proangiogenic phosphoinositide-3-kinase/Akt/eNOS cascade. The NO supplementation strategies rescued defective angiogenesis and salvaged limbs in SKO mice after femoral artery resection.
  
  
  CONCLUSIONS
  Our study shows for the first time downregulation of S100A1 expression in patients with critical limb ischemia and identifies S100A1 as critical for EC function in postnatal ischemic angiogenesis. These findings link its pathological plasticity in critical limb ischemia to impaired neovascularization, prompting further studies to probe the microvascular therapeutic potential of S100A1.
authors.affiliation: Center for Molecular and Translational Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany. patrick.most@med.uni-heidelberg.de
authors.forename: Patrick
authors.initials: P
authors.lastname: Most
authors.forename: Carolin
authors.initials: C
authors.lastname: Lerchenmüller
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Rengo
authors.forename: Adrian
authors.initials: A
authors.lastname: Mahlmann
authors.forename: Julia
authors.initials: J
authors.lastname: Ritterhoff
authors.forename: David
authors.initials: D
authors.lastname: Rohde
authors.forename: Chelain
authors.initials: C
authors.lastname: Goodman
authors.forename: Cornelius J
authors.initials: CJ
authors.lastname: Busch
authors.forename: Felix
authors.initials: F
authors.lastname: Laube
authors.forename: Julian
authors.initials: J
authors.lastname: Heissenberg
authors.forename: Sven T
authors.initials: ST
authors.lastname: Pleger
authors.forename: Norbert
authors.initials: N
authors.lastname: Weiss
authors.forename: Hugo A
authors.initials: HA
authors.lastname: Katus
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Koch
authors.forename: Karsten
authors.initials: K
authors.lastname: Peppel
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology*; D005260:Female; D006614:Hindlimb; D061307:Human Umbilical Vein Endothelial Cells / Q000201:enzymology; D006801:Humans; D007511:Ischemia / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics / Q000503:physiopathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000473:pathology; D018919:Neovascularization, Physiologic / Q000187:drug effects; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034622:RNA Interference; D012039:Regional Blood Flow; D009418:S100 Proteins / Q000172:deficiency* / Q000235:genetics; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism
chemical_list: D020030:Nitric Oxide Donors; D009418:S100 Proteins; C110294:S100A1 protein; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D009569:Nitric Oxide; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D058539:Phosphatidylinositol 3-Kinase; D040301:Vascular Endothelial Growth Factor Receptor-2; D051057:Proto-Oncogene Proteins c-akt; D011493:Protein Kinase C; D002118:Calcium