Vol. 283, Issue 1, H204-H212, July 2002
Differences in E2F subunit expression in quiescent and
proliferating vascular smooth muscle cells
Nobuya
Fujita1,
Yusuke
Furukawa2,
Naoki
Itabashi1,
Koji
Okada1,
Toshikazu
Saito1, and
Shun
Ishibashi1
1 Division of Endocrinology and Metabolism,
Department of Medicine, and 2 Division of Stem Cell
Regulation, Center for Molecular Medicine, Jichi Medical School,
Tochigi 329-0498, Japan
E2F is a family of transcriptional
factors that control G1/S transition. We investigated how
the E2F family participates in the biological responses of vascular
smooth muscle cells (VSMC) to vasoconstrictive hormones compared with
fetal bovine serum (FBS). FBS induced upregulation of E2F-1 and E2F-5
at both mRNA and protein levels and slightly reduced E2F-3 protein.
Angiotensin II (ANG II) and arginine vasopressin increased E2F-3
protein, but not E2F-1 and E2F-5, without upregulating its mRNA level. FBS transactivated the E2F-1 gene through the induction of free E2F-1
binding onto its promoter, whereas ANG II-induced binding of E2F-3 did
not result in activation of the E2F-1 promoter. These changes are
responsible for hypertrophic or hyperplastic response of VSMC to
different growth factors or stimulants. In contrast, both FBS and
vasoconstrictive hormones drove transcription of the cdc6 gene by
downregulating p130 and recruiting free E2F-3 in the latter, which
underlies the progression of VSMC into S phase.
angiotensin II; arginine vasopressin; cell cycle; p130; cdc6