Angiotensin II regulates the cell cycle of vascular smooth muscle cells from SHR.
We have demonstrated that spontaneously hypertensive rats (SHR)-derived vascular smooth muscle cells (VSMC) show the exaggerated growth and produce angiotensin II (Ang II). In the current study, we investigated the role of endogenous Ang II in the regulation of the cell cycle in VSMC from SHR. Levels of Ang II in conditioned medium from SHR-derived VSMC cultured without serum were significantly higher than levels in conditioned medium from Wistar-Kyoto (WKY) rat-derived VSMC. Basal DNA synthesis was higher in quiescent VSMC from SHR than that in cells from WKY rats. An Ang II type 1 receptor antagonist, CV11974, significantly inhibited the elevation in DNA synthesis in quiescent VSMC from SHR but did not affect it in cells from WKY rats. Cellular DNA content analysis by flow cytometry revealed that the proportion of cells in S phase was higher, whereas the proportion of cells in G1+G0 phase was lower in VSMC from SHR than those in cells from WKY rats. CV11974 significantly decreased the proportion of cells in S phase and correspondingly increased the proportion of cells in G1+G0 phase in VSMC from SHR, but it did not affect the proportion in cells from WKY rats. Cyclin-dependent kinase 2 (CDK2) activity, which is known to induce the progression from G1 to S phase, was higher in VSMC from SHR than in cells from WKY rats. Expression of CDK2 inhibitor p27(kip1) mRNA was markedly higher in VSMC from SHR than in cells from WKY rats. CV11974 decreased expression of p27(kip1) mRNA in VSMC from SHR, whereas CV11974 increased it in cells from WKY rats. These findings indicate that enhanced production of endogenous Ang II regulates the cell cycle especially in the progression from G1 to S phase, and increases CDK2 activity, which is independent of p27(kip1) in VSMC from SHR.
Kubo
A
A
Second Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan.
Fukuda
N
N
Teng
J
J
Satoh
C
C
Nakayama
M
M
Kishioka
H
H
Kanmatsuse
K
K
D000804:Angiotensin II / Q000502:physiology*; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D001713:Biphenyl Compounds; D042846:CDC2-CDC28 Kinases; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins; D002478:Cells, Cultured; D051357:Cyclin-Dependent Kinase 2; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis; D005434:Flow Cytometry; D008297:Male; D008869:Microtubule-Associated Proteins / Q000235:genetics; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR / Q000378:metabolism / Q000502:physiology*; D011921:Rats, Inbred WKY; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D013777:Tetrazoles / Q000494:pharmacology; D025521:Tumor Suppressor Proteins
D057911:Angiotensin Receptor Antagonists; D001562:Benzimidazoles; D001713:Biphenyl Compounds; C493962:Cdkn1b protein, rat; D018797:Cell Cycle Proteins; D008869:Microtubule-Associated Proteins; D012333:RNA, Messenger; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D013777:Tetrazoles; D025521:Tumor Suppressor Proteins; D000804:Angiotensin II; 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; C081643:candesartan