Mitochondrial reactive oxygen species regulate spatial profile of proinflammatory responses in lung venular capillaries.
Cytokine-induced lung expression of the endothelial cell (EC) leukocyte receptor P-selectin initiates leukocyte rolling. To understand the early EC signaling that induces the expression, we conducted real-time digital imaging studies in lung venular capillaries. To compare receptor- vs nonreceptor-mediated effects, we infused capillaries with respectively, TNF-alpha and arachidonate. At concentrations adjusted to give equipotent increases in the cytosolic Ca(2+), both agents increased reactive oxygen species (ROS) production and EC P-selectin expression. Blocking the cytosolic Ca(2+) increases abolished ROS production; blocking ROS production abrogated P-selectin expression. TNF-alpha, but not arachidonate, released Ca(2+) from endoplasmic stores and increased mitochondrial Ca(2+). Furthermore, Ca(2+) depletion abrogated TNF-alpha responses partially, but arachidonate responses completely. These differences in Ca(2+) mobilization by TNF-alpha and arachidonate were reflected in spatial patterning in the capillary in that the TNF-alpha effects were localized at branch points, while the arachidonate effects were nonlocalized and extensive. Furthermore, mitochondrial blockers inhibited the TNF-alpha- but not the arachidonate-induced responses. These findings indicate that the different modes of Ca(2+) mobilization determined the spatial patterning of the proinflammatory response in lung capillaries. Responses to TNF-alpha revealed that EC mitochondria regulate the proinflammatory process by generating ROS that activate P-selectin expression.
Parthasarathi
Kaushik
K
St. Luke's-Roosevelt Hospital Center, Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University, New York, NY 10019, USA.
Ichimura
Hideo
H
Quadri
Sadiqa
S
Issekutz
Andrew
A
Bhattacharya
Jahar
J
D000447:Aldehydes / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism; D020013:Calcium Signaling / Q000276:immunology; D002196:Capillaries / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D004730:Endothelium, Vascular / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D005452:Fluoresceins / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D006575:Heterocyclic Compounds, 3-Ring; D007249:Inflammation / Q000276:immunology / Q000378:metabolism; D008168:Lung / Q000098:blood supply* / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D008297:Male; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000276:immunology / Q000378:metabolism / Q000473:pathology / Q000502:physiology*; D019007:P-Selectin / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology; D014680:Veins / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D014966:Xanthenes / Q000378:metabolism
D000447:Aldehydes; D005452:Fluoresceins; D005456:Fluorescent Dyes; D006575:Heterocyclic Compounds, 3-Ring; D019007:P-Selectin; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D014966:Xanthenes; C111472:mitotracker green FM; C121372:mitotracker orange; C068483:rhod-2; C029569:diacetyldichlorofluorescein; D002118:Calcium