title: Lipopolysaccharide (LPS)-mediated angiopoietin-2-dependent autocrine angiogenesis is regulated by NADPH oxidase 2 (Nox2) in human pulmonary microvascular endothelial cells.
abstract: Sepsis-mediated endothelial Angiopoeitin-2 (Ang2) signaling may contribute to microvascular remodeling in the developing lung. The mechanisms by which bacterial cell wall components such as LPS mediate Ang2 signaling in human pulmonary microvascular endothelial cells (HPMECs) remain understudied. In HPMEC, LPS-induced Ang2, Tie2, and VEGF-A protein expression was preceded by increased superoxide formation. NADPH oxidase 2 (Nox2) inhibition, but not Nox4 or Nox1 inhibition, attenuated LPS-induced superoxide formation and Ang2, Tie2, and VEGF-A expression. Nox2 silencing, but not Nox4 or Nox1 silencing, inhibited LPS-mediated inhibitor of κ-B kinase β (IKKβ) and p38 phosphorylation and nuclear translocation of NF-κB and AP-1. In HPMECs, LPS increased the number of angiogenic tube and network formations in Matrigel by >3-fold. Conditioned media from LPS-treated cells also induced angiogenic tube and network formation in the presence of Toll-like receptor 4 blockade but not in the presence of Ang2 and VEGF blockade. Nox2 inhibition or conditioned media from Nox2-silenced cells attenuated LPS-induced tube and network formation. Ang2 and VEGF-A treatment rescued angiogenesis in Nox2-silenced cells. We propose that Nox2 regulates LPS-mediated Ang2-dependent autocrine angiogenesis in HPMECs through the IKKβ/NF-κB and MAPK/AP-1 pathways.
authors.affiliation: From the Departments of Pediatrics and.
authors.forename: Heather
authors.initials: H
authors.lastname: Menden
authors.affiliation: From the Departments of Pediatrics and.
authors.forename: Scott
authors.initials: S
authors.lastname: Welak
authors.affiliation: From the Departments of Pediatrics and.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Cossette
authors.affiliation: From the Departments of Pediatrics and Obstetrics and Gynecology, Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin 53226.
authors.forename: Ramani
authors.initials: R
authors.lastname: Ramchandran
authors.affiliation: From the Departments of Pediatrics and vsampath@mcw.edu.
authors.forename: Venkatesh
authors.initials: V
authors.lastname: Sampath
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D042702:Angiopoietin-2 / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D015151:Immunoblotting; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008168:Lung / Q000098:blood supply; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D055806:Microvessels / Q000166:cytology; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D010766:Phosphorylation / Q000187:drug effects; D034622:RNA Interference; D042787:Receptor, TIE-2 / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D018808:Transcription Factor AP-1 / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D042702:Angiopoietin-2; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D018808:Transcription Factor AP-1; D042461:Vascular Endothelial Growth Factor A; C056558:CYBB protein, human; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; D042787:Receptor, TIE-2; D051550:I-kappa B Kinase; D048051:p38 Mitogen-Activated Protein Kinases
keywords: Angiogenesis; Angiopoeitin-2; Endothelial Cell; LPS; Lung Injury; NADPH Oxidase