A critical role for chloride channel-3 (CIC-3) in smooth muscle cell activation and neointima formation.
OBJECTIVE
We have shown that the chloride-proton antiporter chloride channel-3 (ClC-3) is required for endosome-dependent signaling by the Nox1 NADPH oxidase in SMCs. In this study, we tested the hypothesis that ClC-3 is necessary for proliferation of smooth muscle cells (SMCs) and contributes to neointimal hyperplasia following vascular injury.


RESULTS
Studies were performed in SMCs isolated from the aorta of ClC-3-null and littermate control (wild-type [WT]) mice. Thrombin and tumor necrosis factor-α (TNF-α) each caused activation of both mitogen activated protein kinase extracellular signal-regulated kinases 1 and 2 and the matrix-degrading enzyme matrix metalloproteinase-9 and cell proliferation of WT SMCs. Whereas responses to thrombin were preserved in ClC-3-null SMCs, the responses to TNF-α were markedly impaired. These defects normalized following gene transfer of ClC-3. Carotid injury increased vascular ClC-3 expression, and compared with WT mice, ClC-3-null mice exhibited a reduction in neointimal area of the carotid artery 28 days after injury.


CONCLUSIONS
ClC-3 is necessary for the activation of SMCs by TNF-α but not thrombin. Deficiency of ClC-3 markedly reduces neointimal hyperplasia following vascular injury. In view of our previous findings, this observation is consistent with a role for ClC-3 in endosomal Nox1-dependent signaling. These findings identify ClC-3 as a novel target for the prevention of inflammatory and proliferative vascular diseases.
Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA.
Xi
X
Chu
Mohammed
M
Filali
Bojana
B
Stanic
Maysam
M
Takapoo
Andrea
A
Sheehan
Ramesh
R
Bhalla
Fred S
FS
Lamb
Francis J
FJ
Miller
D000818:Animals; D049109:Cell Proliferation; D002478:Cells, Cultured; D018118:Chloride Channels / Q000235:genetics / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D006965:Hyperplasia; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D023421:Models, Animal; D009131:Muscle, Smooth, Vascular / Q000378:metabolism* / Q000473:pathology*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D000074624:NADPH Oxidase 1; D058426:Neointima / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D018118:Chloride Channels; C115376:ClC-3 channel; D014409:Tumor Necrosis Factor-alpha; D009247:NADH, NADPH Oxidoreductases; D000074624:NADPH Oxidase 1; C000614711:NOX1 protein, mouse; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020780:Matrix Metalloproteinase 9