Canonical WNT Signaling Inhibits Follicle Stimulating Hormone Mediated Steroidogenesis in Primary Cultures of Rat Granulosa Cells
Figure 1
Induction of the WNT signaling pathway.
Specific induction of WNT signaling is demonstrated by regulation of the WNT target gene, Axin2, transcriptional regulation of CTNNB1/TCF luciferase reporter and the transcriptional co-factor CTNNB1. Primary rat granulosa cells were treated for 24 h with vehicle or increasing doses of recombinant WNT3A (1, 5, 50, or 500 ng/mL) in the presence or absence of FSH (100 ng/mL). (A) Graphical representation of Axin2 mRNA expression and (B) tabular representation of Axin 2 mRNA expression data analyzed by real-time PCR (n = 5). (C) CTNNB1/TCF-dependent (TOPflash) transcriptional activity in primary GC (n = 3) and a GC tumor cell line (inset, n = 3). Statistical significance is presented as the mean ± standard error of the mean with significance set at (P<0.05). Results of WNT treatment are compared within experimental groups incubated without (grey bars) and with (black bars) FSH treatment. Means with the same letter do not differ significantly. (D) Representative Western blot and quantitative analysis (n = 3) of CTNNB1 protein demonstrates an increase in CTNNB1 abundance after treatment with WNT3A alone (P<0.05) and co-treatment of WNT3A + FSH (P<0.01) compared with controls.