Endothelial Microparticle-Derived Reactive Oxygen Species: Role in Endothelial Signaling and Vascular Function.
Endothelial microparticles are effectors of endothelial damage; however mechanisms involved are unclear. We examined the effects of eMPs on cultured endothelial cells (ECs) and isolated vessels and investigated the role of eMP-derived reactive oxygen species (ROS) and redox signaling in these processes. eMPs were isolated from EC media and their ability to directly produce ROS was assessed by lucigenin and liquid chromatography. Nicotinamide adenine dinucleotide phosphate oxidase (Nox) subunits were probed by Western blot. ECs were treated with eMPs and effects on kinase signaling, superoxide anion (O2 (∙-)) generation, and nitric oxide (NO) production were examined. Acetylcholine-mediated vasorelaxation was assessed by myography in eMP-treated mesenteric arteries. eMPs contained Nox1, Nox2, Nox4, p47(phox), p67(phox), and p22(phox) and they produced ROS which was inhibited by the Nox inhibitor, apocynin. eMPs increased phosphorylation of ERK1/2 and Src, increased O2 (∙-) production, and decreased A23187-induced NO production in ECs. Pretreatment of eMPs with apocynin diminished eMP-mediated effects on ROS and NO production but had no effect on eMP-mediated kinase activation or impairment in vasorelaxation. Our findings identify a novel mechanism whereby eMP-derived ROS contributes to MP bioactivity. These interactions may be important in conditions associated with vascular injury and increased eMP formation.
Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, 2501-451 Smyth Road, Ottawa, ON, Canada K1H 8M5.
Dylan
D
Burger
Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, 2501-451 Smyth Road, Ottawa, ON, Canada K1H 8M5.
Maddison
M
Turner
Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, 2501-451 Smyth Road, Ottawa, ON, Canada K1H 8M5.
Mercedes N
MN
Munkonda
Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, 2501-451 Smyth Road, Ottawa, ON, Canada K1H 8M5; Institute of Cardiovascular & Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, 126 University Place, Glasgow G12 8TA, UK.
Rhian M
RM
Touyz
D000818:Animals; D055252:Cell-Derived Microparticles / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D008638:Mesenteric Arteries / Q000187:drug effects / Q000378:metabolism*; D008810:Mice, Inbred C57BL; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D010766:Phosphorylation; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; D014665:Vasodilator Agents; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D019255:NADPH Oxidases