Thiocyanate-dependent induction of endothelial cell adhesion molecule expression by phagocyte peroxidases: a novel HOSCN-specific oxidant mechanism to amplify inflammation.
Both eosinophil peroxidase (EPO) and neutrophil myeloperoxidase (MPO) preferentially oxidize SCN(-) to generate HOSCN, a weak, sulfhydryl-reactive oxidant, as a major physiologic product. We here show that HOSCN is a uniquely potent phagocyte oxidant inducer of E-selectin, ICAM-1, and VCAM-1 expression in HUVEC as detected by Western blot and flow cytometry. EMSA and inhibitor studies show that HOSCN up-regulation of these adhesion molecules is transcriptionally mediated through a mechanism that is dependent upon activation of the NF-kappaB p65/p50 transcription factor and constitutively suppressed by PI3K-Akt pathway activity. HUVEC monolayers exposed to HOSCN bind 8-fold more neutrophils and 3- to 4-fold more Aml14.3D10 cells (a differentiated cell line model of mature eosinophils) than control monolayers. Blocking Ab studies confirm the involvement of E-selectin and ICAM-1 but not VCAM-1 in neutrophil adhesion and of all three in Aml14.3D10 adhesion. Intraperitoneal injection of HOSCN evoked an 8-fold increase in neutrophil peritoneal extravasation. In addition to NF-kappaB, HOSCN also activates the potentially proinflammatory transcription factors Stat4, CDP, GRE, CBF, Ets-1/PEA3, and TFIID, a pattern easily distinguishable from that induced by LPS. These results suggest that phagocyte peroxidases function to amplify inflammation through a novel, HOSCN-specific oxidant mechanism.
Wang
Jian-Guo
JG
Department of Medicine, Hematology, Oncology and Transplantation Division and The Vascular Biology Center, University of Minnesota, 420 Delaware Street SE, Minneapolis, MN 55455, USA.
Mahmud
Shawn A
SA
Nguyen
Julia
J
Slungaard
Arne
A
D015815:Cell Adhesion Molecules / Q000235:genetics; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology; D047209:Eosinophil Peroxidase; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D007249:Inflammation / Q000209:etiology; D009504:Neutrophils / Q000201:enzymology / Q000502:physiology; D016877:Oxidants / Q000502:physiology; D009195:Peroxidase; D010544:Peroxidases / Q000378:metabolism* / Q000502:physiology; D010586:Phagocytes / Q000187:drug effects / Q000201:enzymology*; D013861:Thiocyanates / Q000378:metabolism / Q000494:pharmacology*; D014157:Transcription Factors / Q000187:drug effects; D014471:Umbilical Veins / Q000166:cytology; D019010:Vascular Cell Adhesion Molecule-1 / Q000235:genetics*
D015815:Cell Adhesion Molecules; D016877:Oxidants; D013861:Thiocyanates; D014157:Transcription Factors; D019010:Vascular Cell Adhesion Molecule-1; D047209:Eosinophil Peroxidase; D010544:Peroxidases; D009195:Peroxidase; C031760:thiocyanate