title: Fluid shear stress upregulates placental growth factor in the vessel wall via NADPH oxidase 4.
abstract: Placental growth factor (PLGF), a potent stimulator of arteriogenesis, is upregulated during outward arterial remodeling. Increased fluid shear stress (FSS) is a key physiological stimulus for arteriogenesis. However, the role of FSS in regulating PLGF expression is unknown. To test the hypothesis that FSS regulates PLGF expression in vascular cells and to identify the signaling pathways involved, human coronary artery endothelial cells (HCAEC) and human coronary artery smooth muscle cells were cultured on either side of porous Transwell inserts. HCAEC were then exposed to pulsatile FSS of 0.07 Pa ("normal," mimicking flow through quiescent collaterals), 1.24 Pa ("high," mimicking increased flow in remodeling collaterals), or 0.00 Pa ("static") for 2 h. High FSS increased secreted PLGF protein ∼1.4-fold compared with static control (n = 5, P < 0.01), while normal FSS had no significant effect on PLGF. Similarly, high flow stimulated PLGF mRNA expression nearly twofold in isolated mouse mesenteric arterioles. PLGF knockdown using siRNA revealed that HCAEC were the primary source of PLGF in cocultures (n = 5, P < 0.01). Both H2O2 and nitric oxide production were increased by FSS compared with static control (n = 5, P < 0.05). N(G)-nitro-l-arginine methyl ester (100 μM) had no significant effect on the FSS-induced increase in PLGF. In contrast, both catalase (500 U/ml) and diphenyleneiodonium (5 μM) attenuated the effects of FSS on PLGF protein in cocultures. Diphenyleneiodonium also blocked the effect of high flow to upregulate PLGF mRNA in isolated arterioles. Further studies identified NADPH oxidase 4 as a source of reactive oxygen species for this pathway. We conclude that FSS regulates PLGF expression via NADPH oxidase 4 and reactive oxygen species signaling.
authors.affiliation: Department of Physiological Sciences, Oklahoma State University, Stillwater, Oklahoma.
authors.forename: Nabil A
authors.initials: NA
authors.lastname: Rashdan
authors.affiliation: Department of Physiological Sciences, Oklahoma State University, Stillwater, Oklahoma pamela.lloyd@okstate.edu.
authors.forename: Pamela G
authors.initials: PG
authors.lastname: Lloyd
mesh_terms: D000818:Animals; D001160:Arterioles / Q000187:drug effects / Q000378:metabolism*; D002374:Catalase / Q000494:pharmacology; D002478:Cells, Cultured; D018920:Coculture Techniques; D003097:Collateral Circulation; D003331:Coronary Vessels / Q000166:cytology; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D020869:Gene Expression Profiling; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D009861:Onium Compounds / Q000494:pharmacology; D000072483:Placenta Growth Factor; D011257:Pregnancy Proteins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D011673:Pulsatile Flow; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction; D013314:Stress, Mechanical; D015854:Up-Regulation; D066253:Vascular Remodeling
chemical_list: D009566:Nitrates; D009573:Nitrites; D009861:Onium Compounds; C000608036:PGF protein, human; C000608037:Pgf protein, mouse; D011257:Pregnancy Proteins; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D000072483:Placenta Growth Factor; C007517:diphenyleneiodonium; D006861:Hydrogen Peroxide; D002374:Catalase; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498910:NOX4 protein, human; C422943:Nox4 protein, mouse; D019331:NG-Nitroarginine Methyl Ester
keywords: arteriogenesis; collateral circulation; endothelium; hemodynamics; vascular endothelial growth factors