Transcriptional activation of steroidogenic factor-1 by hypomethylation of the 5' CpG island in endometriosis.
BACKGROUND
Endometriosis is an estrogen-dependent disease. Steroidogenic factor-1 (SF-1), a transcriptional factor essential for activation of multiple steroidogenic genes for estrogen biosynthesis, is undetectable in normal endometrial stromal cells and aberrantly expressed in endometriotic stromal cells.


OBJECTIVE
The objective of the study was to unravel the mechanism for differential SF-1 expression in endometrial and endometriotic stromal cells.


METHODS
We identified a CpG island flanking the SF-1 promoter and exon I region and determined its methylation patterns in endometrial and endometriotic cells.


METHODS
The study was conducted at Northwestern University.


METHODS
Eutopic endometrium from disease-free subjects (n = 8) and the walls of cystic endometriosis lesions of the ovaries (n = 8) were investigated.


METHODS
Stromal cells were isolated from these two types of tissues.


METHODS
Measures are mentioned in Results.


RESULTS
SF-1 mRNA and protein levels in endometriotic stromal cells were significantly higher than those in endometrial stromal cells (P < 0.001). Bisulfite sequencing showed strikingly increased methylation in endometrial cells, compared with endometriotic cells (P < 0.001). Demethylation by 5-aza-2'-deoxycytidine increased SF-1 mRNA levels by up to 55.48-fold in endometrial cell (P < 0.05). Luciferase assays showed that the -85/+239 region bearing the CpG island regulated its activity (P < 0.01). Natural or in vitro methylation of this region strikingly reduced SF-1 promoter activity in both cell types (P < 0.01). Chromatin immunoprecipitation assay showed that methyl-CpG-binding domain protein 2 binds to the SF-1 promoter in endometrial but not endometriotic cells.


CONCLUSIONS
This is the first demonstration of methylation-dependent regulation of SF-1 in any mammalian tissue. These findings point to a new mechanism for targeting local estrogen biosynthesis in endometriosis.
Xue
Qing
Q
Division of Reproductive Biology Research, Department of Obstetrics and Gynecology, Northwestern University, Chicago, Illinois 60611, USA.
Lin
Zhihong
Z
Yin
Ping
P
Milad
Magdy P
MP
Cheng
You-Hong
YH
Confino
Edmond
E
Reierstad
Scott
S
Bulun
Serdar E
SE
D001141:Aromatase / Q000096:biosynthesis; D047072:Aromatase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology / Q000627:therapeutic use; D015153:Blotting, Western; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism; D018899:CpG Islands / Q000235:genetics*; D019175:DNA Methylation; D000077209:Decitabine; D004715:Endometriosis / Q000235:genetics*; D004791:Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D005260:Female; D017930:Genes, Reporter / Q000235:genetics; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000235:genetics*; D006801:Humans; D047468:Immunoprecipitation; D008156:Luciferases / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis* / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D054339:Steroidogenic Factor 1; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics*; D015533:Transcriptional Activation / Q000235:genetics / Q000502:physiology*; D014162:Transfection
D047072:Aromatase Inhibitors; D002843:Chromatin; D004791:Enzyme Inhibitors; D018398:Homeodomain Proteins; C515057:NR5A1 protein, human; D018160:Receptors, Cytoplasmic and Nuclear; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; D012313:RNA; D000077209:Decitabine; D008156:Luciferases; D001141:Aromatase; D001374:Azacitidine