E4F1, a novel estrogen-responsive gene in possible atheroprotection, revealed by microarray analysis.
Estrogen has been postulated to be involved in inhibition of vascular smooth muscle cell (VSMC) proliferation mainly via estrogen receptor (ER), but the detailed mechanism has remained primarily unknown. Therefore, in this study, microarray analysis was used in two types of cultured human VSMCs: one positive for ER alpha, and the other for ER beta, which were treated by estrogens to detect the estrogen-responsive genes. We also used quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) to evaluate mRNA levels of selective target gene (TG) in these cells. We further studied whether the TG product was involved in inhibition of proliferation using small interfering RNA (siRNA) of the TG transfection. We subsequently used quantitative RT-PCR and in situ hybridization analysis to evaluate the expression of these gene products in human aorta. E4F1, a possible inducer of cell growth arrest, was markedly increased only in ER alpha-positive VSMCs by estrogens in both microarray and RT-PCR analyses. Blocking of E4F1 using siRNA suppressed estrogenic inhibition of ER alpha-positive VSMC proliferation. E4F1 mRNA was abundant in premenopausal female aorta with mild atherosclerotic changes. E4F1 is therefore considered one of the estrogen-responsive genes involving ER alpha-mediated inhibition of VSMC proliferation and may play an important role in estrogen-related atheroprotection of human aorta.
Nakamura
Yasuhiro
Y
Department of Pathology, Tohoku University School of Medicine, Aoba-ku, Sendai 980-8575, Japan. nakamura@patholo2.med.tohoku.ac.jp
Igarashi
Katsuhide
K
Suzuki
Takashi
T
Kanno
Jun
J
Inoue
Tohru
T
Tazawa
Chika
C
Saruta
Masayuki
M
Ando
Tomoko
T
Moriyama
Noriko
N
Furukawa
Toru
T
Ono
Masao
M
Moriya
Takuya
T
Ito
Kiyoshi
K
Saito
Haruo
H
Ishibashi
Tadashi
T
Takahashi
Shoki
S
Yamada
Shogo
S
Sasano
Hironobu
H
D017504:Adenovirus E4 Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D001011:Aorta / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D001161:Arteriosclerosis / Q000378:metabolism / Q000517:prevention & control*; D049109:Cell Proliferation / Q000187:drug effects; D047628:Estrogen Receptor alpha / Q000032:analysis / Q000235:genetics; D047629:Estrogen Receptor beta / Q000032:analysis / Q000235:genetics; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D046228:Microarray Analysis; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D010750:Phosphoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D017697:Premenopause; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017504:Adenovirus E4 Proteins; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens; D010750:Phosphoproteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D012097:Repressor Proteins; C411663:transcription factor p120(E4F)