Regulation and regulatory role of WNT signaling in potentiating FSH action during bovine dominant follicle selection.

PloS one (2014-06-18)
P S P Gupta, Joseph K Folger, Sandeep K Rajput, Lihua Lv, Jianbo Yao, James J Ireland, George W Smith
RESUMEN

Follicular development occurs in wave like patterns in monotocous species such as cattle and humans and is regulated by a complex interaction of gonadotropins with local intrafollicular regulatory molecules. To further elucidate potential mechanisms controlling dominant follicle selection, granulosa cell RNA harvested from F1 (largest) and F2 (second largest) follicles isolated at predeviation (PD) and onset of diameter deviation (OD) stages of the first follicular wave was subjected to preliminary RNA transcriptome analysis. Expression of numerous WNT system components was observed. Hence experiments were performed to test the hypothesis that WNT signaling modulates FSH action on granulosa cells during follicular waves. Abundance of mRNA for WNT pathway members was evaluated in granulosa cells harvested from follicles at emergence (EM), PD, OD and early dominance (ED) stages of the first follicular wave. In F1 follicles, abundance of CTNNB1 and DVL1 mRNAs was higher and AXIN2 mRNA was lower at ED versus EM stages and DVL1 and FZD6 mRNAs were higher and AXIN2 mRNA was lower in F1 versus F2 follicle at the ED stage. Bovine granulosa cells were treated in vitro with increasing doses of the WNT inhibitor IWR-1+/- maximal stimulatory dose of FSH. IWR-1 treatment blocked the FSH-induced increase in granulosa cell numbers and reduced the FSH-induced increase in estradiol. Granulosa cells were also cultured in the presence or absence of FSH +/- IWR-1 and hormonal regulation of mRNA for WNT pathway members and known FSH targets determined. FSH treatment increased CYP19A1, CCND2, CTNNB1, AXIN2 and FZD6 mRNAs and the stimulatory effect on CYP19A1 mRNA was reduced by IWR-1. In contrast, FSH reduced CARTPT mRNA and IWR-1 partially reversed the inhibitory effect of FSH. Results support temporal and hormonal regulation and a potential role for WNT signaling in potentiating FSH action during dominant follicle selection.

MATERIALES
Referencia del producto
Marca
Descripción del producto

Sigma-Aldrich
Sodium selenite, BioReagent, suitable for cell culture, ≥98%
Sigma-Aldrich
Sodium selenite, 99%
Sigma-Aldrich
Sodium selenite, γ-irradiated, lyophilized powder, BioXtra, suitable for cell culture
Sigma-Aldrich
IWR-1, ≥98% (HPLC)
Sigma-Aldrich
Estradiol, meets USP testing specifications
Supelco
Estradiol, Pharmaceutical Secondary Standard; Certified Reference Material
Supelco
4-Androstene-3,17-dione, VETRANAL®, analytical standard
Sigma-Aldrich
Sodium selenite, anhydrous, ≥90.0% (RT)
Sigma-Aldrich
Anti-AXIN2 antibody produced in rabbit, Prestige Antibodies® Powered by Atlas Antibodies, affinity isolated antibody, buffered aqueous glycerol solution
USP
Estradiol, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
Anti-AXIN2 antibody produced in rabbit, affinity isolated antibody, buffered aqueous solution