Transactivation of steroidogenic acute regulatory protein in human endometriotic stromalcells is mediated by the prostaglandin EP2 receptor.

Abstract

Steroidogenic acute regulatory protein (StAR) regulates the first committed step in the biosynthesis of steroids, and thus aberrant expression of StAR in endometriotic implants plays a critical role in the etiology of endometriosis. However, the mechanism responsible for abnormal expression of StAR in ectopic endometriotic tissues remains unknown. In the present study, we demonstrate that prostaglandin (PG) E(2) stimulates StAR protein expression at the cellular and molecular levels. PGE(2) caused a rapid increase in StAR expression that involves activation of the EP2 receptor-coupled protein kinase A pathway. Activation of EP2 receptor-induced phosphorylation of ERK and cAMP response element binding protein (CREB). However, activation of ERK did not involve in CREB phosphorylation or concomitantly StAR expression. Phosphorylation of CREB induced by PGE(2) increased the recruitment of CREB binding protein and thus histone H3 acetylation. Chromatin immunoprecipitation experiments showed that acetylated histone H3 bound to the proximal region of the StAR promoter was increased after 30 min treatment with PGE(2), and this was mirrored by an increase in nascent StAR RNA transcription. Treatment with the histone deacetylase inhibitor, tricostatin A, enhanced PGE(2)-induced nascent StAR RNA transcription. We conclude that increased histone H3 acetylation involving the EP2 receptor, protein kinase A, CREB, and CREB binding protein is responsible for PGE(2)-induced StAR gene activation in endometriotic stromal cells. Our current report may provide new insights in understanding mechanism of abnormally local production of estrogen and the etiology of endometriosis.

• Authors: H Sunny Sun, Kuei-Yang Hsiao, Chih-Chao Hsu, Meng-Hsing Wu, Shaw-Jenq Tsai
• Journal: Endocrinology (Endocrinology) Vol. 144 Issue 9 Pg. 3934-42 (Sep 2003) ISSN: 0013-7227 [Print] United States
• PMID: 12933667 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Activating Transcription Factor 2
• Chromatin
• Cyclic AMP Response Element-Binding Protein
• Histones
• PTGER2 protein, human
• Phosphoproteins
• RNA, Messenger
• Receptors, Prostaglandin E
• Receptors, Prostaglandin E, EP2 Subtype
• Transcription Factors
• steroidogenic acute regulatory protein
• Cyclic AMP-Dependent Protein Kinases
• Mitogen-Activated Protein Kinases

Topics

• Acetylation
• Activating Transcription Factor 2
• Base Sequence
• Cells, Cultured
• Chromatin (physiology)
• Cyclic AMP Response Element-Binding Protein (metabolism)
• Cyclic AMP-Dependent Protein Kinases (metabolism)
• Endometrium (cytology, metabolism)
• Female
• Gene Expression (physiology)
• Histones (metabolism)
• Humans
• Mitogen-Activated Protein Kinases (metabolism)
• Molecular Sequence Data
• Phosphoproteins (genetics, metabolism)
• Phosphorylation
• Promoter Regions, Genetic (physiology)
• RNA, Messenger (metabolism)
• Receptors, Prostaglandin E (genetics, metabolism)
• Receptors, Prostaglandin E, EP2 Subtype
• Signal Transduction (physiology)
• Stromal Cells (metabolism)
• Transcription Factors (metabolism)