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Title: Downregulation of cyclin-dependent kinase inhibitor; p57{sup kip2}, is involved in the cell cycle progression of vascular smooth muscle cells

Abstract

Immature vascular smooth muscle cells (VSMCs) proliferate responding to extrinsic mitogens and accumulate in neointima after arterial injuries. Cell proliferation is positively regulated by cyclin/cyclin-dependent kinase (CDK) complex and negatively controlled by CDK inhibitors; CKIs such as p27{sup kip1} and p57{sup kip2}. In this study, embryonic rat thoracic aorta VSMCs; A10 were G0/G1 arrested by serum starvation, re-stimulated with serum, and harvested every four hours. Both CKIs co-expressed in quiescent VSMCs and rapidly diminished by stimulation. Protein level of p27{sup kip1} was regulated by both transcription and post-transcription, but that of p57{sup kip2} was mainly by post-transcription. Supplemental overexpression of p57{sup kip2} inhibited the activations of G1 cyclin/CDKs and subsequent hyperphosphorylations of all three retinoblastoma pocket proteins as well as G1/S transition of cell cycle. Our findings suggest that the downregulations of not only p27{sup kip1}, but also p57{sup kip2} responding to mitogenic stimulation, play key roles in the cell cycle progression of VSMCs.

Authors:
 [1];  [2];  [2];  [2];  [2];  [3];  [3];  [2];  [3];  [2]
  1. Department of Cardiovascular Medicine, Graduate School of Medicine, Hokkaido University, Sapporo 060-8638 (Japan). E-mail: norida@med.hokudai.ac.jp
  2. Department of Cardiovascular Medicine, Graduate School of Medicine, Hokkaido University, Sapporo 060-8638 (Japan)
  3. Division of Molecular Oncology, Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815 (Japan)
Publication Date:
OSTI Identifier:
20793239
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 338; Journal Issue: 3; Other Information: DOI: 10.1016/j.bbrc.2005.10.093; PII: S0006-291X(05)02344-2; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; AORTA; CELL CYCLE; CELL PROLIFERATION; INJURIES; MITOGENS; MUSCLES; PROTEINS; RATS; STIMULATION; TRANSCRIPTION

Citation Formats

Nakano, Noritsugu, Urasawa, Kazushi, Takagi, Yasushi, Saito, Takahiko, Kaneta, Satoshi, Ishikawa, Susumu, Higashi, Hideaki, Tsutsui, Hiroyuki, Hatakeyama, Masanori, and Kitabatake, Akira. Downregulation of cyclin-dependent kinase inhibitor; p57{sup kip2}, is involved in the cell cycle progression of vascular smooth muscle cells. United States: N. p., 2005. Web. doi:10.1016/J.BBRC.2005.1.
Nakano, Noritsugu, Urasawa, Kazushi, Takagi, Yasushi, Saito, Takahiko, Kaneta, Satoshi, Ishikawa, Susumu, Higashi, Hideaki, Tsutsui, Hiroyuki, Hatakeyama, Masanori, & Kitabatake, Akira. Downregulation of cyclin-dependent kinase inhibitor; p57{sup kip2}, is involved in the cell cycle progression of vascular smooth muscle cells. United States. doi:10.1016/J.BBRC.2005.1.
Nakano, Noritsugu, Urasawa, Kazushi, Takagi, Yasushi, Saito, Takahiko, Kaneta, Satoshi, Ishikawa, Susumu, Higashi, Hideaki, Tsutsui, Hiroyuki, Hatakeyama, Masanori, and Kitabatake, Akira. Fri . "Downregulation of cyclin-dependent kinase inhibitor; p57{sup kip2}, is involved in the cell cycle progression of vascular smooth muscle cells". United States. doi:10.1016/J.BBRC.2005.1.
@article{osti_20793239,
title = {Downregulation of cyclin-dependent kinase inhibitor; p57{sup kip2}, is involved in the cell cycle progression of vascular smooth muscle cells},
author = {Nakano, Noritsugu and Urasawa, Kazushi and Takagi, Yasushi and Saito, Takahiko and Kaneta, Satoshi and Ishikawa, Susumu and Higashi, Hideaki and Tsutsui, Hiroyuki and Hatakeyama, Masanori and Kitabatake, Akira},
abstractNote = {Immature vascular smooth muscle cells (VSMCs) proliferate responding to extrinsic mitogens and accumulate in neointima after arterial injuries. Cell proliferation is positively regulated by cyclin/cyclin-dependent kinase (CDK) complex and negatively controlled by CDK inhibitors; CKIs such as p27{sup kip1} and p57{sup kip2}. In this study, embryonic rat thoracic aorta VSMCs; A10 were G0/G1 arrested by serum starvation, re-stimulated with serum, and harvested every four hours. Both CKIs co-expressed in quiescent VSMCs and rapidly diminished by stimulation. Protein level of p27{sup kip1} was regulated by both transcription and post-transcription, but that of p57{sup kip2} was mainly by post-transcription. Supplemental overexpression of p57{sup kip2} inhibited the activations of G1 cyclin/CDKs and subsequent hyperphosphorylations of all three retinoblastoma pocket proteins as well as G1/S transition of cell cycle. Our findings suggest that the downregulations of not only p27{sup kip1}, but also p57{sup kip2} responding to mitogenic stimulation, play key roles in the cell cycle progression of VSMCs.},
doi = {10.1016/J.BBRC.2005.1},
journal = {Biochemical and Biophysical Research Communications},
number = 3,
volume = 338,
place = {United States},
year = {Fri Dec 23 00:00:00 EST 2005},
month = {Fri Dec 23 00:00:00 EST 2005}
}
  • AngiotensinII (AngII) induces vascular smooth muscle cell (VSMC) proliferation, which plays an important role in the development and progression of hypertension. AngII-induced cellular events have been implicated, in part, in the activation of protein kinase C (PKC) and extracellular signal-regulated kinases 1/2 (ERK1/2). In the present study, we investigated the effect of Ib, a novel nonpeptide AngII receptor type 1 (AT{sub 1}) antagonist, on the activation of PKC and ERK1/2 in VSMC proliferation induced by AngII. MTT, and [{sup 3}H]thymidine incorporation assay showed that AngII-induced VSMC proliferation was inhibited significantly by Ib. The specific binding of [{sup 125}I]AngII to AT{submore » 1} receptors was blocked by Ib in a concentration-dependent manner with IC{sub 50} value of 0.96 nM. PKC activity assay and Western blot analysis demonstrated that Ib significantly inhibited the activation of PKC and phosphorylation of ERK1/2 induced by AngII, respectively. Furthermore, AngII-induced ERK1/2 activation was obviously blocked by GF109203X, a PKC inhibitor. These findings suggest that the suppression of Ib on AngII-induced VSMC proliferation may be attributed to its inhibitory effect on PKC-dependent ERK1/2 pathway.« less
  • Ceramide 1-phosphate (C1P) is a novel bioactive sphingolipid formed by ceramide kinase (CERK)-catalyzed phosphorylation of ceramide. It has been implicated in the regulation of such vital pathophysiological functions as phagocytosis and inflammation, but there have been no reports ascribing a biological function to CERK in vascular disorders. Here the potential role of CERK/C1P in neointimal formation was investigated using rat aortic vascular smooth muscle cells (VSMCs) in primary culture and a rat carotid injury model. Exogenous C8-C1P stimulated cell proliferation, DNA synthesis, and cell cycle progression of rat aortic VSMCs in primary culture. In addition, wild-type CERK-transfected rat aortic VSMCsmore » induced a marked increase in rat aortic VSMC proliferation and [{sup 3}H]-thymidine incorporation when compared to empty vector transfectant. C8-C1P markedly activated extracellular signal-regulated kinase 1 and 2 (ERK1/2) within 5 min, and the activation could be prevented by U0126, a MEK inhibitor. Also, K1, a CERK inhibitor, decreased the ERK1/2 phosphorylation and cell proliferation on platelet-derived growth factor (PDGF)-stimulated rat aortic VSMCs. CERK expression and C1P levels were found to be potently increased during neointimal formation using a rat carotid injury model. However, ceramide levels decreased during the neointimal formation process. These findings suggest that C1P can induce neointimal formation via cell proliferation through the regulation of the ERK1/2 protein in rat aortic VSMCs and that CERK/C1P may regulate VSMC proliferation as an important pathogenic marker in the development of cardiovascular disorders.« less
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