title: The potentiation of myeloperoxidase activity by the glycosaminoglycan-dependent binding of myeloperoxidase to proteins of the extracellular matrix.
abstract: BACKGROUND
  Myeloperoxidase (MPO) is an abundant hemoprotein expressed by neutrophil granulocytes that is recognized to play an important role in the development of vascular diseases. Upon degranulation from circulating neutrophil granulocytes, MPO binds to the surface of endothelial cells in an electrostatic-dependent manner and undergoes transcytotic migration to the underlying extracellular matrix (ECM). However, the mechanisms governing the binding of MPO to subendothelial ECM proteins, and whether this binding modulates its enzymatic functions are not well understood.
  
  
  METHODS
  We investigated MPO binding to ECM derived from aortic endothelial cells, aortic smooth muscle cells, and fibroblasts, and to purified ECM proteins, and the modulation of these associations by glycosaminoglycans. The oxidizing and chlorinating potential of MPO upon binding to ECM proteins was tested.
  
  
  RESULTS
  MPO binds to the ECM proteins collagen IV and fibronectin, and this association is enhanced by the pre-incubation of these proteins with glycosaminoglycans. Correspondingly, an excess of glycosaminoglycans in solution during incubation inhibits the binding of MPO to collagen IV and fibronectin. These observations were confirmed with cell-derived ECM. The oxidizing and chlorinating potential of MPO was preserved upon binding to collagen IV and fibronectin; even the potentiation of MPO activity in the presence of collagen IV and fibronectin was observed.
  
  
  CONCLUSIONS
  Collectively, the data reveal that MPO binds to ECM proteins on the basis of electrostatic interactions, and MPO chlorinating and oxidizing activity is potentiated upon association with these proteins.
  
  
  CONCLUSIONS
  Our findings provide new insights into the molecular mechanisms underlying the interaction of MPO with ECM proteins.
authors.affiliation: Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic. kubalal@ibp.cz
authors.forename: Lukáš
authors.initials: L
authors.lastname: Kubala
authors.forename: Hana
authors.initials: H
authors.lastname: Kolářová
authors.forename: Jan
authors.initials: J
authors.lastname: Víteček
authors.forename: Silvie
authors.initials: S
authors.lastname: Kremserová
authors.forename: Anna
authors.initials: A
authors.lastname: Klinke
authors.forename: Denise
authors.initials: D
authors.lastname: Lau
authors.forename: Anna L P
authors.initials: AL
authors.lastname: Chapman
authors.forename: Stephan
authors.initials: S
authors.lastname: Baldus
authors.forename: Jason P
authors.initials: JP
authors.lastname: Eiserich
mesh_terms: D002478:Cells, Cultured; D024141:Collagen Type IV / Q000378:metabolism; D019281:Dimerization; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000737:chemistry / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism*; D006801:Humans; D009566:Nitrates / Q000378:metabolism; D018384:Oxidative Stress; D009195:Peroxidase / Q000378:metabolism*; D011485:Protein Binding; D014443:Tyrosine / Q000378:metabolism
chemical_list: D024141:Collagen Type IV; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D006025:Glycosaminoglycans; D009566:Nitrates; D014443:Tyrosine; D009195:Peroxidase
keywords: 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid; 3,3′,5,5′-tetramethylbenzidine; 5,5′-dithiobis(2-nitrobenzoic) acid; 5-thio-2-nitrobenzoic acid; ABTS; BAECs; BSA; CTAC; Cardiovascular disease; Collagen IV; DMF; DTNB; ECM; EDTA; ELISA; Endothelium; Enzyme activity; Fibronectin; GAGs; HRP; Inflammation; MCD; MPO; N,N-dimethylformamide; OD; PBS; RASMCs; RT; SEM; TMB; TNB; bovine aortic endothelial cells; bovine serum albumin; cetyltrimethylammonium chloride; enzyme-linked immunosorbent assay; ethylenediaminetetraacetic acid; extracellular matrix; glycosaminoglycans; horseradish peroxidase; monochlorodimedon; myeloperoxidase; optical density; phosphate buffered saline; rat aortic smooth muscle cells; room temperature; standard error of the mean