G protein-coupled receptor Ca2+-linked mitochondrial reactive oxygen species are essential for endothelial/leukocyte adherence.
Receptor-mediated signaling is commonly associated with multiple functions, including the production of reactive oxygen species. However, whether mitochondrion-derived superoxide (mROS) contributes directly to physiological signaling is controversial. Here we demonstrate a previously unknown mechanism in which physiologic Ca(2+)-evoked mROS production plays a pivotal role in endothelial cell (EC) activation and leukocyte firm adhesion. G protein-coupled receptor (GPCR) and tyrosine kinase-mediated inositol 1,4,5-trisphosphate-dependent mitochondrial Ca(2+) uptake resulted in NADPH oxidase-independent mROS production. However, GPCR-linked mROS production did not alter mitochondrial function or trigger cell death but rather contributed to activation of NF-kappaB and leukocyte adhesion via the EC induction of intercellular adhesion molecule 1. Dismutation of mROS by manganese superoxide dismutase overexpression and a cell-permeative superoxide dismutase mimetic ablated NF-kappaB transcriptional activity and facilitated leukocyte detachment from the endothelium under simulated circulation following GPCR- but not cytokine-induced activation. These results demonstrate that mROS is the downstream effector molecule that translates receptor-mediated Ca(2+) signals into proinflammatory signaling and leukocyte/EC firm adhesion.
Hawkins
Brian J
BJ
Institute for Environmental Medicine, University of Pennsylvania, Philadelphia, PA 19104-6068, USA.
Solt
Laura A
LA
Chowdhury
Ibrul
I
Kazi
Altaf S
AS
Abid
M Ruhul
MR
Aird
William C
WC
May
Michael J
MJ
Foskett
J Kevin
JK
Madesh
Muniswamy
M
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D002448:Cell Adhesion / Q000187:drug effects; D002645:Chickens; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects / Q000648:ultrastructure; D006801:Humans; D007249:Inflammation; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D007962:Leukocytes / Q000166:cytology* / Q000187:drug effects; D051379:Mice; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D019255:NADPH Oxidases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D044463:Receptor, PAR-1 / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism; D013917:Thrombin / Q000494:pharmacology
D053496:Inositol 1,4,5-Trisphosphate Receptors; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D044463:Receptor, PAR-1; D043562:Receptors, G-Protein-Coupled; D013481:Superoxides; D018799:Intercellular Adhesion Molecule-1; D019255:NADPH Oxidases; D013917:Thrombin; D002118:Calcium