The AhR is constitutively activated and affects granulosa cell features in the human cell line KGN.
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The AhR is constitutively activated and affects granulosa cell features in the human cell line KGN. / Horling, Katja; Santos, Anne Navarrete; Fischer, Bernd.
in: MOL HUM REPROD, Jahrgang 17, Nr. 2, 2, 2011, S. 104-114.Publikationen: SCORING: Beitrag in Fachzeitschrift/Zeitung › SCORING: Zeitschriftenaufsatz › Forschung › Begutachtung
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T1 - The AhR is constitutively activated and affects granulosa cell features in the human cell line KGN.
AU - Horling, Katja
AU - Santos, Anne Navarrete
AU - Fischer, Bernd
PY - 2011
Y1 - 2011
N2 - 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 ? (ER?) 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.
AB - 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 ? (ER?) 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.
KW - Humans
KW - Female
KW - Enzyme-Linked Immunosorbent Assay
KW - Cell Proliferation
KW - Cell Line
KW - Polymerase Chain Reaction
KW - Signal Transduction
KW - Aromatase/genetics
KW - Aryl Hydrocarbon Hydroxylases/genetics
KW - Benzoflavones/pharmacology
KW - Cytochrome P-450 CYP1A1/genetics
KW - Estrogens/biosynthesis
KW - Flavonoids/pharmacology
KW - Granulosa Cells/drug effects/metabolism
KW - Ovary/metabolism
KW - Receptors, Aryl Hydrocarbon/antagonists & inhibitors/genetics/metabolism
KW - Receptors, Estrogen/genetics/metabolism
KW - Receptors, Gonadotropin/genetics/metabolism
KW - Tetrachlorodibenzodioxin/pharmacology
KW - beta-Naphthoflavone/pharmacology
KW - Humans
KW - Female
KW - Enzyme-Linked Immunosorbent Assay
KW - Cell Proliferation
KW - Cell Line
KW - Polymerase Chain Reaction
KW - Signal Transduction
KW - Aromatase/genetics
KW - Aryl Hydrocarbon Hydroxylases/genetics
KW - Benzoflavones/pharmacology
KW - Cytochrome P-450 CYP1A1/genetics
KW - Estrogens/biosynthesis
KW - Flavonoids/pharmacology
KW - Granulosa Cells/drug effects/metabolism
KW - Ovary/metabolism
KW - Receptors, Aryl Hydrocarbon/antagonists & inhibitors/genetics/metabolism
KW - Receptors, Estrogen/genetics/metabolism
KW - Receptors, Gonadotropin/genetics/metabolism
KW - Tetrachlorodibenzodioxin/pharmacology
KW - beta-Naphthoflavone/pharmacology
M3 - SCORING: Journal article
VL - 17
SP - 104
EP - 114
JO - MOL HUM REPROD
JF - MOL HUM REPROD
SN - 1360-9947
IS - 2
M1 - 2
ER -
