Regulation of aromatase P450 expression in endometriotic and endometrial stromal cells by CCAAT/enhancer binding proteins (C/EBPs): Decreased C/EBPβ in endometriosis is associated with overexpression of aromatase

Sijun Yang, Zongjuan Fang, Takashi Suzuki, Hironobu Sasano, Jianfeng Zhou, Bilgin Gurates, Mitsutoshi Tamura, Karen Ferrer, Serdar Bulun

研究成果: Article査読

80 被引用数 (Scopus)

抄録

In human endometriotic stromal cells, markedly high levels of aromatase P450 (P450arom) mRNA and promoter II activity are present and can be vigorously stimulated by PGE2 via a cAMP-dependent pathway to give rise to physiologically significant estrogen biosynthesis. Stromal cells of eutopic endometrium, on the other hand, do not express sufficient levels of P450arom for detectable enzyme activity. Because P450arom is up-regulated in the ovaries of CCAAT/enhancer binding protein (C/EBP) β knockout mice and activation of the ovarian-type P450arom promoter (II) is responsible for aberrant P450arom expression in endometriosis, we sought here to evaluate the possible roles of C/EBP isoforms in the regulation of P450arom expression in endometriotic vs. eutopic endometrial stromal cells. We previously found that the -517-bp flanking region of promoter II contained the critical cis-acting elements for baseline and cAMP (analog)-induced activity. In this study, we disrupted several potential sequences and found that mutations of a -211/-197-bp cAMP-response element (CRE) and a -317/-304-bp C/EBP binding site abolished both baseline and cAMP-induced promoter II activity. Ectopic expression of C/EBPα increased both baseline and cAMP-dependent promoter II activity significantly in endometriotic cells, whereas ectopic expression of C/EBPβ or C/EBPδ abolished promoter II activity in both untreated and cAMP-treated endometriotic stromal cells. Comparable changes in promoter II activity were observed using endometrial stromal cells, which showed, however, seemingly diminished levels of baseline and cAMP-induced promoter II activity in comparison with endometriotic cells. EMSA using a probe containing the critical -317/-304-bp C/EBP site upstream of promoter II demonstrated a distinct DNA-protein complex in endometriotic, but not in endometrial stromal cells. This specific complex, however, could not be altered using antibodies against C/EBPα, -β, or -δ. Because CRE is another potential DNA motif that can bind C/EBP isoforms, we next used EMSA using a probe containing the -211/-197-bp CRE and demonstrated that specific DNA-protein complexes contained C/EBPα but not C/EBPβ or C/EBPδ in endometriotic stromal cells. In contrast, C/EBPβ and C/EBPδ but not C/EBPα were detected in DNA-protein complexes using nuclear extracts from endometrial stromal cells. Western blotting and immunohistochemistry demonstrated expression of C/EBPα, -β, and -δ in human endometriotic and endometrial stroma and epithelium. Intriguingly, C/EBPβ was expressed at increased levels in stromal cells of human eutopic endometrium compared with simultaneously biopsied endometriotic tissues. We conclude that both -317/-304 and -211/-197-bp elements in promoter II are critical for the robust cAMP-dependent induction in endometriosis. C/EBPα up-regulates, whereas C/EBPβ and C/EBPδ inhibit P450arom promoter activity via binding primarily to the -211/-197-bp CRE under in vitro conditions. In vivo down-regulation of C/EBPβ in endometriotic stromal cells and its up-regulation in endometrial stromal cells may in part account for the induction of P450arom expression in endometriosis and its inhibition in endometrium.

本文言語English
ページ(範囲)2336-2345
ページ数10
ジャーナルJournal of Clinical Endocrinology and Metabolism
87
5
DOI
出版ステータスPublished - 2002

ASJC Scopus subject areas

  • 内分泌学、糖尿病および代謝内科学
  • 生化学
  • 内分泌学
  • 臨床生化学
  • 生化学、医学

フィンガープリント

「Regulation of aromatase P450 expression in endometriotic and endometrial stromal cells by CCAAT/enhancer binding proteins (C/EBPs): Decreased C/EBPβ in endometriosis is associated with overexpression of aromatase」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

引用スタイル