title: Bone morphogenic protein 4 produced in endothelial cells by oscillatory shear stress induces monocyte adhesion by stimulating reactive oxygen species production from a nox1-based NADPH oxidase.
abstract: Atherosclerosis is an inflammatory disease occurring preferentially in arterial regions exposed to disturbed flow conditions including oscillatory shear stress (OS). OS exposure induces endothelial expression of bone morphogenic protein 4 (BMP4), which in turn may activate intercellular adhesion molecule-1 (ICAM-1) expression and monocyte adhesion. OS is also known to induce monocyte adhesion by producing reactive oxygen species (ROS) from reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, raising the possibility that BMP4 may stimulate the inflammatory response by ROS-dependent mechanisms. Here we show that ROS scavengers blocked ICAM-1 expression and monocyte adhesion induced by BMP4 or OS in endothelial cells (ECs). Similar to OS, BMP4 stimulated H2O2 and O2- production in ECs. Next, we used ECs obtained from p47phox-/- mice (MAE-p47-/-), which do not produce ROS in response to OS, to determine the role of NADPH oxidases. Similar to OS, BMP4 failed to induce monocyte adhesion in MAE-p47-/-, but it was restored when the cells were transfected with p47phox plasmid. Moreover, OS-induced O2- production was blocked by noggin (a BMP antagonist), suggesting a role for BMP. Furthermore, OS increased gp91phox (nox2) and nox1 mRNA levels while decreasing nox4. In contrast, BMP4 induced nox1 mRNA expression, whereas nox2 and nox4 were decreased or not affected, respectively. Also, OS-induced monocyte adhesion was blocked by knocking down nox1 with the small interfering RNA (siRNA). Finally, BMP4 siRNA inhibited OS-induced ROS production and monocyte adhesion. Together, these results suggest that BMP4 produced in ECs by OS stimulates ROS release from the nox1-dependent NADPH oxidase leading to inflammation, a critical early atherogenic step.
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga 30322, USA.
authors.forename: George P
authors.initials: GP
authors.lastname: Sorescu
authors.forename: Hannah
authors.initials: H
authors.lastname: Song
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Tressel
authors.forename: Jinah
authors.initials: J
authors.lastname: Hwang
authors.forename: Sergey
authors.initials: S
authors.lastname: Dikalov
authors.forename: Debra A
authors.initials: DA
authors.lastname: Smith
authors.forename: Nolan L
authors.initials: NL
authors.lastname: Boyd
authors.forename: Manu O
authors.initials: MO
authors.lastname: Platt
authors.forename: Bernard
authors.initials: B
authors.lastname: Lassègue
authors.forename: Kathy K
authors.initials: KK
authors.lastname: Griendling
authors.forename: Hanjoong
authors.initials: H
authors.lastname: Jo
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D002448:Cell Adhesion; D002478:Cells, Cultured / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology*; D005786:Gene Expression Regulation; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D009000:Monocytes / Q000166:cytology*; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000074624:NADPH Oxidase 1; D019255:NADPH Oxidases; D010750:Phosphoproteins / Q000172:deficiency / Q000235:genetics; D034622:RNA Interference; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology; D012212:Rheology; D013314:Stress, Mechanical; D013481:Superoxides / Q000378:metabolism; D014162:Transfection
chemical_list: D000975:Antioxidants; C525809:BMP4 protein, human; C525810:Bmp4 protein, mouse; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; D013481:Superoxides; D018799:Intercellular Adhesion Molecule-1; D006861:Hydrogen Peroxide; D009247:NADH, NADPH Oxidoreductases; D000074624:NADPH Oxidase 1; D019255:NADPH Oxidases; C000614711:NOX1 protein, mouse; C060505:neutrophil cytosolic factor 1