Upstream stimulatory factor-2 regulates steroidogenic factor-1 expression in endometriosis.
Local estrogen biosynthesis is a major factor in the pathogenesis of endometriosis. Aberrant expression of steroidogenic acute regulatory protein (StAR) and aromatase in endometriotic tissue leads to an up-regulation of estrogen production. The transcription factor steroidogenic factor-1 (SF-1) activates the promoters of both StAR and aromatase in endometriotic tissue. We investigated differences in SF-1 expression in endometriotic tissue and normally located endometrium to elucidate the mechanism underlying increased StAR and aromatase activities in endometriosis. Serial deletion and site-directed mutants of the SF-1 promoter showed that an E-box sequence was critical for its activity in endometriotic stromal cells. EMSAs showed that the upstream stimulatory factor (USF) 1 and 2 in nuclear extracts from endometrial and endometriotic stromal cells bound to the E-box. Chromatin-immunoprecipitation-PCR assay, however, demonstrated in intact cells that binding activity of USF2 to the SF-1 promoter was strikingly higher than that of USF1 in endometriotic stromal cells and that USF1 or USF2 binding activity was hardly detectable in endometrial stromal cells. Moreover, knockdown of USF2 but not USF1 resulted in robust and consistent down-regulation of SF-1 and its target genes StAR and aromatase in endometriotic stromal cells. USF2 but not USF1 mRNA and protein levels were significantly higher in endometriotic vs. endometrial stromal cells. In vivo, USF2 mRNA and immunoreactive USF2 levels in endometriotic tissues were strikingly higher than those in endometrium. Taken together, the elevated levels of USF2 in endometriosis account for, in part, the aberrant expression of SF-1 and its target gene StAR and aromatase.
Utsunomiya
Hiroki
H
Division of Reproductive Biology Research, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA.
Cheng
You-Hong
YH
Lin
Zhihong
Z
Reierstad
Scott
S
Yin
Ping
P
Attar
Erkut
E
Xue
Qing
Q
Imir
Gonca
G
Thung
Steven
S
Trukhacheva
Elena
E
Suzuki
Takashi
T
Sasano
Hironobu
H
Kim
J Julie
JJ
Yaegashi
Nobuo
N
Bulun
Serdar E
SE
D001141:Aromatase / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D004715:Endometriosis / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D004717:Endometrium / Q000378:metabolism / Q000473:pathology; D005260:Female; D015870:Gene Expression; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D054339:Steroidogenic Factor 1 / Q000235:genetics* / Q000378:metabolism; D017154:Stromal Cells / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics; D014162:Transfection; D051720:Upstream Stimulatory Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D012333:RNA, Messenger; D034741:RNA, Small Interfering; D054339:Steroidogenic Factor 1; C497181:USF1 protein, human; C497184:USF2 protein, human; D051720:Upstream Stimulatory Factors; D001141:Aromatase