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Compartmentalized nitric oxide signaling at the myoendothelial junction can regulate gap junction communication
Author(s) -
Straub Adam C.,
Johnstone Scott R.,
Best Angela K.,
Palmer Lisa,
Isakson Brant E.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.591.4
Subject(s) - enos , nitric oxide , gap junction , stimulation , microbiology and biotechnology , s nitrosylation , nitrosylation , biology , nitric oxide synthase , chemistry , biophysics , biochemistry , endocrinology , cysteine , intracellular , enzyme
Myoendothelial junctions (MEJ) couple endothelial cells (EC) and vascular smooth muscle cells (SMC) in resistance vessels via gap junctions (GJ). Throughout the MEJ, caveolin‐1, which regulates endothelial nitric oxide synthase (eNOS) derived nitric oxide (NO), is extensively localized. Therefore, we tested the hypothesis that eNOS is compartmentalized at the MEJ and that NO can regulate heterocellular communication by S‐nitrosylation of connexin (Cx) proteins. To test this, we immunolabeled for eNOS and identified its expression at the MEJ in vivo (by TEM) and in our vascular cell co‐culture (VCCC) model (by confocal). We found increased eNOS phosphorylation at serine 1177 at the MEJ compared to the EC monolayer. This eNOS phosphorylation was selectively increased at the MEJ upon stimulation of SMCs with phenylephrine (PE) but not at the EC monolayer. Using the biotin switch assay, we determined the degree of S‐nitrosylated Cx43 at the MEJ. One minute after PE stimulation of SMCs, de‐nitrosylation of Cx43 was observed, followed by progressive re‐nitrosylation up to 20 min post‐PE stimulation. Functionally, this correlated with an inhibition of UV‐uncaged IP 3 movement from SMC to EC 1 min after PE stimulation, which was restored 20 mins post PE stimulation. These results suggest that S‐nitrosylation of Cx proteins likely maintain open GJ channels and can contribute to heterocellular communication at the MEJ.