title: Critical role of lipid raft redox signaling platforms in endostatin-induced coronary endothelial dysfunction.
abstract: OBJECTIVE
  Endostatin (EST) was found to initiate a redox signaling cascade associated with activation of NADPH oxidase in endothelial cells (ECs). The present study tested whether EST stimulates clustering of ceramide-enriched lipid rafts (LRs), which assembles and activates NADPH oxidase to form redox signaling platforms.
  
  
  RESULTS
  Using confocal microscopy, we first demonstrated a colocalization of LR clusters with NADPH oxidase subunits, gp91(phox) and p47(phox) in the ECs membrane on EST stimulation. Immunoblot analysis of floated detergent-resistant membrane fractions found that in LR fractions NADPH oxidase subunits gp91(phox) and p47(phox) are enriched and that the activity of this enzyme increased dramatically, as measured by electron spin resonance (ESR) spectrometry. This EST-increased LR platform formation was shown to be attenuated by inhibition or RNA interference of acid sphingomyelinase (A-SMase). Functionally, EST pretreatment significantly impaired bradykinin or A23187-induced vasodilation in isolated small coronary arteries, which could be partially reversed by LR disruptors.
  
  
  CONCLUSIONS
  The early injury effect of EST on the vascular endothelium is associated with the formation of redox signaling platforms via lipid raft clustering.
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, 410 N 12th, Richmond, VA 23298, USA.
authors.forename: Si
authors.initials: S
authors.lastname: Jin
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Fan
authors.initials: F
authors.lastname: Yi
authors.forename: Pin-Lan
authors.initials: PL
authors.lastname: Li
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001920:Bradykinin; D000001:Calcimycin; D002417:Cattle; D002478:Cells, Cultured; D002518:Ceramides / Q000378:metabolism; D016000:Cluster Analysis; D003327:Coronary Disease / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology; D003331:Coronary Vessels / Q000378:metabolism* / Q000473:pathology*; D004108:Dilatation, Pathologic / Q000139:chemically induced / Q000378:metabolism; D043169:Endostatins; D042783:Endothelial Cells / Q000378:metabolism*; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D018613:Microscopy, Confocal; D019255:NADPH Oxidases / Q000378:metabolism; D010084:Oxidation-Reduction; D011336:Probability; D012313:RNA / Q000032:analysis; D015398:Signal Transduction
chemical_list: D002518:Ceramides; D043169:Endostatins; D000001:Calcimycin; D012313:RNA; D019255:NADPH Oxidases; D001920:Bradykinin