TGF-β1 induces COX-2 expression and PGE2 production in human granulosa cells through Smad signaling pathways.
BACKGROUND
Cyclooxygenase-2 (COX-2) expression and prostaglandin E2 (PGE2) production have been shown to play key roles in the regulation of ovulation. The TGF-β superfamily members are important molecules that regulate many ovarian functions under normal physiological and pathological conditions. TGF-β1 and its receptors are expressed in human granulosa cells. However, to date, whether TGF-β1 can regulate COX-2 expression and PGE2 production, which in turn contribute to the process of ovulation, remains unknown.


OBJECTIVE
The objective of the study was to investigate the effects of TGF-β1 on COX-2 expression and PGE2 production in human granulosa cells.


METHODS
SVOG cells are human granulosa cells that were obtained from women undergoing in vitro fertilization and immortalized with Simian virus 40 large T antigen. SVOG cells were used to investigate the effect of TGF-β1 on COX-2 expression and PGE2 production.


METHODS
The study was conducted at an academic research center.


METHODS
mRNA and protein levels were examined by RT-quantitative real-time PCR and Western blotting, respectively. The concentrations of PGE2 in the culture medium were measured by an ELISA.


RESULTS
TGF-β1 treatment induced COX-2 expression and PGE2 production. The inductive effects of TGF-β1 on COX-2 and PGE2 were abolished by the inhibition of TGF-β type I receptor (TβRI). In addition, treatment with TGF-β1 activated phosphorylated mothers against decapentaplegic (Smad)-2 and Smad3 signaling pathways. Inhibition of the Smad signaling pathways by small interfering RNA-mediated approaches attenuated the TGF-β1-induced COX-2 expression and PGE2 production.


CONCLUSIONS
TGF-β1 induced PGE2 production by inducing the COX-2 expression through a Smad-dependent signaling pathway in human granulosa cells.
Reproductive Medical Center (L.F., Y.-P.S.), The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China 450052; and Department of Obstetrics and Gynaecology (L.F., H.-M.C., J.-C.C., P.C.K.L.), Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada V5Z 4H4.
Lanlan
L
Fang
Hsun-Ming
HM
Chang
Jung-Chien
JC
Cheng
Peter C K
PC
Leung
Ying-Pu
YP
Sun
D066258:Amphiregulin; D066259:Betacellulin; D002478:Cells, Cultured; D051546:Cyclooxygenase 2 / Q000235:genetics* / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism*; D066255:EGF Family of Proteins; D004815:Epidermal Growth Factor / Q000494:pharmacology; D066260:Epiregulin; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006023:Glycoproteins / Q000494:pharmacology; D006107:Granulosa Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000502:physiology; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D051785:Smad Proteins / Q000502:physiology*; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*
C587848:AREG protein, human; D066258:Amphiregulin; C587851:BTC protein, human; D066259:Betacellulin; D066255:EGF Family of Proteins; C587880:EREG protein, human; D066260:Epiregulin; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D018125:Receptors, Transforming Growth Factor beta; D051785:Smad Proteins; D053773:Transforming Growth Factor beta1; D004815:Epidermal Growth Factor; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; D015232:Dinoprostone