RRC ID 18633
Author Horling K, Santos AN, Fischer B.
Title The AhR is constitutively activated and affects granulosa cell features in the human cell line KGN.
Journal Mol. Hum. Reprod.
Abstract A well-balanced activity of the aryl hydrocarbon receptor (AhR) is necessary for normal ovarian function. As known from murine AhR knock-out (KO) models, the AhR is involved in folliculogenesis, gonadotrophin receptor expression, proliferation of granulosa cells and intraovarian estrogen signalling. Highly potent, non-physiological ligands such as the dioxin 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) lead to a blockade of ovulation, estrogen receptor degradation and reduction of estrogen levels. Estrogen synthesis is a typical function of granulosa cells and essential for normal cyclicity and fertility. We employed the human granulosa cell line KGN to further characterize AhR signalling and AhR function in granulosa cell physiology. Real-time PCR quantification of the target genes Cyp1a1 and Cyp1b1 and reporter gene assays after stimulation with TCDD or beta-naphthoflavone (BNF) or inhibition with alpha-naphthoflavone (ANF) or 3'-methoxy-4'-nitroflavone (3,4-MNF) of the AhR demonstrated constitutive activity and functionality of AhR pathway in KGN granulosa cells. In untreated KGN cells, AhR protein was exclusively detected in the nuclear fraction. TCDD stimulation affected the gonadotrophin receptor but not estrogen receptor β (ERβ) protein expression. Additionally, the constitutively activated AhR suppressed aromatase expression and estrogen synthesis (enzyme-linked immunoassay, ELISA) and enhanced proliferation [Bromodeoxyuridine (BrdU) ELISA] of KGN cells. Activation of the AhR by BNF did not override this inhibitory effect on estrogen synthesis or proliferation. In conclusion, the AhR pathway is constitutively activated and functional in human KGN granulosa cells. It is a potential target for endocrine disruption by exogenous ligands and subsequent dysfunction of granulosa cells.
Volume 17(2)
Pages 104-14
Published 2011-2
DOI 10.1093/molehr/gaq074
PII gaq074
PMID 20823264
MeSH Aromatase / genetics Aryl Hydrocarbon Hydroxylases / genetics Benzoflavones / pharmacology Cell Line Cell Proliferation Cytochrome P-450 CYP1A1 / genetics Cytochrome P-450 CYP1B1 Enzyme-Linked Immunosorbent Assay Estrogens / biosynthesis Female Flavonoids / pharmacology Granulosa Cells / drug effects Granulosa Cells / metabolism* Humans Ovary / metabolism Polychlorinated Dibenzodioxins / pharmacology Polymerase Chain Reaction Receptors, Aryl Hydrocarbon / antagonists & inhibitors Receptors, Aryl Hydrocarbon / genetics* Receptors, Aryl Hydrocarbon / metabolism* Receptors, Estrogen / genetics Receptors, Estrogen / metabolism Receptors, Gonadotropin / genetics Receptors, Gonadotropin / metabolism Signal Transduction* beta-Naphthoflavone / pharmacology
IF 3.396
Times Cited 6
Human and Animal Cells KGN (RCB1154)