p27(Kip1) is important in modulating pulmonary artery smooth muscle cell proliferation.
Vascular remodeling due to pulmonary arterial smooth muscle cell (PASMC) proliferation is central to the development of pulmonary hypertension. Cell proliferation requires the coordinated interaction of cyclins and cyclin-dependent kinases (cdk) to drive cells through the cell cycle. Cdk inhibitors can bind cyclin-cdk complexes and cause G(1) arrest. To determine the importance of the cdk inhibitor p27(Kip1) in PASMC proliferation we studied [(3)H]thymidine incorporation, changes in cell cycle, cell proliferation, and protein expression of p27(Kip1) following serum stimulation in early passage rat PASMC. p27(Kip1) expression decreased to 40% of baseline after serum stimulation, which was associated with an increase in both [(3)H]thymidine incorporation and the percent of cells in S phase. p27(Kip1) binding to cyclin E decreased at 24 h, and this correlated with an increase in phosphorylation of retinoblastoma both in vivo and in vitro. Overexpression of p27(Kip1) decreased [(3)H]thymidine incorporation and reduced cell counts at 5 d compared with controls. PASMC obtained from p27(Kip1-/-) mice showed a 2-fold increase in [(3)H]thymidine incorporation (at 24 h) and cell proliferation compared with p27(Kip1+/+) PASMC when cultured in 10% fetal bovine serum (FBS). These results suggest an important role for p27(Kip1) in regulating PASMC mitogenesis and proliferation.
Fouty
B W
BW
Center for Genetic Lung Disease and Division of Pulmonary Sciences and Critical Care Medicine, Department of Biochemistry, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA. brian.fouty@uchsc.edu
Grimison
B
B
Fagan
K A
KA
Le Cras
T D
TD
Harral
J W
JW
Hoedt-Miller
M
M
Sclafani
R A
RA
Rodman
D M
DM
D000818:Animals; D001798:Blood Proteins / Q000494:pharmacology; D042846:CDC2-CDC28 Kinases; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D019927:Cyclin E / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis; D005434:Flow Cytometry; D015870:Gene Expression / Q000502:physiology; D006973:Hypertension / Q000378:metabolism; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000201:enzymology; D016296:Mutagenesis / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011651:Pulmonary Artery / Q000166:cytology* / Q000201:enzymology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013936:Thymidine / Q000493:pharmacokinetics; D014316:Tritium; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism*
D001798:Blood Proteins; C493962:Cdkn1b protein, rat; D018797:Cell Cycle Proteins; D019927:Cyclin E; D025521:Tumor Suppressor Proteins; D014316:Tritium; D050760:Cyclin-Dependent Kinase Inhibitor p27; D004247:DNA; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495892:Cdk2 protein, rat; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; D013936:Thymidine