Low-voltage-activated (T-type) calcium channels control proliferation of human pulmonary artery myocytes.
While Ca2+ influx is essential for activation of the cell cycle machinery, the processes that regulate Ca2+ influx in this context have not been fully elucidated. Electrophysiological and molecular studies have identified multiple Ca2+ channel genes expressed in mammalian cells. Ca(v)3.x gene family members, encoding low voltage-activated (LVA) or T-type channels, were first identified in the central nervous system and subsequently in non-neuronal tissue. Reports of a potential role for T-type Ca2+ channels in controlling cell proliferation conflict. The present study tested the hypothesis that T-type Ca2+ channels, encoded by Ca(v)3.x genes, control pulmonary artery smooth muscle cell proliferation and cell cycle progression. Using quantitative RT/PCR, immunocytochemistry, and immunohistochemistry we found that Ca(v)3.1 was the predominant Ca(v)3.x channel expressed in early passage human pulmonary artery smooth muscle cells in vitro and in the media of human pulmonary arteries, in vivo. Selective blockade of Ca(v)3.1 expression with small interfering RNA (siRNA) and pharmacological blockade of T-type channels completely inhibited proliferation in response to 5% serum and prevented cell cycle entry. These studies establish that T-type voltage-operated Ca2+ channels are required for cell cycle progression and proliferation of human PA SMC.
Rodman
David M
DM
Center for Genetic Lung Disease, University of Colorado Health Sciences Center, Denver, Colo 80262, USA. david.rodman@uchsc.edu
Reese
Katherine
K
Harral
Julie
J
Fouty
Brian
B
Wu
Songwei
S
West
James
J
Hoedt-Miller
Marloes
M
Tada
Yuji
Y
Li
Kai-Xun
KX
Cool
Carlyne
C
Fagan
Karen
K
Cribbs
Leanne
L
D020747:Calcium Channels, T-Type / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D004110:Diltiazem / Q000494:pharmacology; D006801:Humans; D008168:Lung / Q000378:metabolism; D020748:Mibefradil / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000166:cytology* / Q000378:metabolism; D011651:Pulmonary Artery / Q000166:cytology*; D034741:RNA, Small Interfering / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction
C121855:CACNA1G protein, human; D020747:Calcium Channels, T-Type; D034741:RNA, Small Interfering; D020748:Mibefradil; D004110:Diltiazem