Compartmentalized connexin 43 s-nitrosylation/denitrosylation regulates heterocellular communication in the vessel wall.
OBJECTIVE
To determine whether S-nitrosylation of connexins (Cxs) modulates gap junction communication between endothelium and smooth muscle.


RESULTS
Heterocellular communication is essential for endothelium control of smooth muscle constriction; however, the exact mechanism governing this action remains unknown. Cxs and NO have been implicated in regulating heterocellular communication in the vessel wall. The myoendothelial junction serves as a conduit to facilitate gap junction communication between endothelial cells and vascular smooth muscle cells within the resistance vasculature. By using isolated vessels and a vascular cell coculture, we found that Cx43 is constitutively S-nitrosylated on cysteine 271 because of active endothelial NO synthase compartmentalized at the myoendothelial junction. Conversely, we found that stimulation of smooth muscle cells with the constrictor phenylephrine caused Cx43 to become denitrosylated because of compartmentalized S-nitrosoglutathione reductase, which attenuated channel permeability. We measured S-nitrosoglutathione breakdown and NO(x) concentrations at the myoendothelial junction and found S-nitrosoglutathione reductase activity to precede NO release.


CONCLUSIONS
This study provides evidence for compartmentalized S-nitrosylation/denitrosylation in the regulation of smooth muscle cell to endothelial cell communication.
Department of Molecular Physiology and Biological Physics, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
Adam C
AC
Straub
Marie
M
Billaud
Scott R
SR
Johnstone
Angela K
AK
Best
Sean
S
Yemen
Scott T
ST
Dwyer
Robin
R
Looft-Wilson
Jeffery J
JJ
Lysiak
Ben
B
Gaston
Lisa
L
Palmer
Brant E
BE
Isakson
D000426:Alcohol Dehydrogenase; D000818:Animals; D002450:Cell Communication / Q000502:physiology*; D002478:Cells, Cultured; D018031:Connexin 43 / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D017629:Gap Junctions / Q000378:metabolism*; D005980:Glutathione Reductase / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D023421:Models, Animal; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010656:Phenylephrine / Q000494:pharmacology; D026422:S-Nitrosoglutathione / Q000378:metabolism*; D014655:Vascular Resistance / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D018031:Connexin 43; C543076:GJA1 protein, mouse; D014662:Vasoconstrictor Agents; D010656:Phenylephrine; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; C483598:Adh5 protein, mouse; D000426:Alcohol Dehydrogenase; D052250:Nitric Oxide Synthase Type III; D005980:Glutathione Reductase