Journal article
Lhcgr Expression in Granulosa Cells: Roles for PKA-Phosphorylated β-Catenin, TCF3, and FOXO1
Molecular endocrinology (Baltimore, Md.), Vol.27(8), pp.1295-1310
08/01/2013
Handle:
https://hdl.handle.net/2376/115293
PMCID: PMC3725343
PMID: 23754802
Abstract
Ovarian follicles lacking FSH or FSH receptors fail to progress to a preovulatory stage, resulting in infertility. One hallmark of the preovulatory follicle is the presence of luteinizing hormone/choriogonadotropin receptors (LHCGR) on granulosa cells (GCs). However, the mechanisms by which FSH induces Lhcgr gene expression are poorly understood. Our results show that protein kinase A (PKA) and phosphoinositide 3-kinase (PI3K)/AKT pathways are required for FSH to activate both the murine Lhcgr-luciferase reporter and expression of Lhcgr mRNA in rat GCs. Based on results showing that an adenovirus (Ad) expressing a steroidogenic factor 1 (SF1) mutant that cannot bind β-catenin abolished FSH-induced Lhcgr mRNA, we evaluated the role of β-catenin in the regulation of Lhcgr gene expression. FSH promoted the PKA-dependent, PI3K-independent phosphorylation of β-catenin on Ser552 and Ser665. FSH activated the β-catenin/T-cell factor (TCF) artificial promoter-reporter TOPFlash via a PKA-dependent, PI3K-independent pathway, and dominant-negative (DN) TCF abolished FSH-activated Lhcgr-luciferase reporter and induction of Lhcgr mRNA. Microarray analysis of GCs treated with Ad-DN-TCF and FSH identified the Lhcgr as the most down-regulated gene. Chromatin immunoprecipitation results placed β-catenin phosphorylated on Ser552 and Ser675 and SF1 on the Lhcgr promoter in FSH-treated GCs; TCF3 was constitutively associated with the Lhcgr promoter. Transduction with an Ad-phospho-β-catenin mutant (Ser552/665/Asp) enhanced Lhcgr mRNA expression in FSH-treated cells greater than 3-fold. Finally, we identified a recognized PI3K/AKT target, forkhead box O1, as a negative regulator of Lhcgr mRNA expression. These results provide new understanding of the complex regulation of Lhcgr gene expression in GCs.
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Details
- Title
- Lhcgr Expression in Granulosa Cells: Roles for PKA-Phosphorylated β-Catenin, TCF3, and FOXO1
- Creators
- Nathan C Law - 1School of Molecular Biosciences, Washington State University, Pullman, Washington 99164Jennifer Weck - 1School of Molecular Biosciences, Washington State University, Pullman, Washington 99164Brandon Kyriss - 1School of Molecular Biosciences, Washington State University, Pullman, Washington 99164John H Nilson - 1School of Molecular Biosciences, Washington State University, Pullman, Washington 99164Mary Hunzicker-Dunn - 1School of Molecular Biosciences, Washington State University, Pullman, Washington 99164
- Publication Details
- Molecular endocrinology (Baltimore, Md.), Vol.27(8), pp.1295-1310
- Academic Unit
- Molecular Biosciences, School of
- Publisher
- Oxford University Press
- Identifiers
- 99900548204001842
- Language
- English
- Resource Type
- Journal article