Involvement of chloride channels in IGF-I-induced proliferation of porcine arterial smooth muscle cells.
OBJECTIVE
The existence of Cl- channels in vascular smooth muscle cells (VSMCs) has been increasingly investigated, but the biological functions are not yet clear. Insulin-like growth factor (IGF)-I affects proliferation and migration of VSMCs, and dysregulation of this axis may be involved in atherogenesis and intimal hyperplasia. We examined the effects of Cl- channel blockers on IGF-I-induced proliferation in porcine VSMCs. The siRNA approach was used to support the role of ClC-2, a member of the volume-regulated Cl- channel family, in cell proliferation of VSMCs.


RESULTS
The IGF-I-induced VSMC proliferation was significantly suppressed by the Cl- channel blockers NPPB and IAA94 but not by DIDS. IGF-I-induced cell proliferation parallels a significant increase in the endogenous expression of ClC-2 mRNA and protein. Inhibitors of PI3-kinase, LY294002 and wortmannin, significantly attenuated the IGF-I-upregulated ClC-2 expression and cell proliferation. We observed ClC-2-like Cl- current, and this current was augmented by IGF-I. SiRNA specifically targeted to ClC-2 abolished IGF-I-induced cell proliferation.


CONCLUSIONS
Our data demonstrate that ClC-2 plays a role in IGF-1-induced regulation of VSMC proliferation in cardiovascular diseases.
Cheng
Gang
G
Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE 68178, USA.
Kim
Min-Jung
MJ
Jia
Guanghong
G
Agrawal
Devendra K
DK
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western / Q000379:methods; D000090007:CLC-2 Chloride Channels; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D018118:Chloride Channels / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002867:Chromones / Q000494:pharmacology; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008297:Male; D009025:Morpholines / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034622:RNA Interference; D034741:RNA, Small Interfering; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine; D000077191:Wortmannin
D000730:Androstadienes; D000090007:CLC-2 Chloride Channels; D018118:Chloride Channels; D002867:Chromones; D005419:Flavonoids; D009025:Morpholines; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D034741:RNA, Small Interfering; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D007334:Insulin-Like Growth Factor I; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D000077191:Wortmannin