Sequential gonadotropin treatment of immature mice leads to amplification of transforming growth factor beta action, via upregulation of receptor-type 1, Smad 2 and 4, and downregulation of Smad 6.
The present study was designed to establish the cellular localization and expression of transforming growth factor beta (TGFbeta) signaling pathway components, including TGFbeta1 and beta2; TGFbeta receptors type I (TbetaRI) and II (TbetaRII); and Smads 2, 3, 4, and 6 during gonadotropin-induced follicular maturation and ovulation in the mouse ovary. Immature 21-day-old mice were sequentially treated with recombinant human FSH, 5 IU daily for 3 days, and hCG once at Day 24 of life. Immunohistochemical experiments revealed a TGFbeta1 staining in granulosa cells (GC) and theca interna cells (TIC) as well as in oocytes, whereas that of TGFbeta2 was mainly localized in oocytes and GC. Strong immunostaining for both TbetaRI and -RII was observed in the TIC and, to a lesser extent, in GC. Whereas oocytes did not exhibit any staining for TbetaRII, their TbetaRI immunostaining was strong. Smads were detected in oocytes, GC, and luteal cells and in a lesser amount in TIC; the immunostaining for Smad 4 was the strongest. Western blotting and reverse transcription-polymerase chain reaction analyses indicated that, in response to gonadotropins, TGFbeta2, TbetaRI, Smad 2 and Smad 4 mRNA and protein levels increased, while those of Smad 6 decreased in ovarian homogenates. In conclusion, these results show that, in a model of immature mouse exposed to a sequential gonadotropin treatment, FSH and LH increased the expression of the TGFbeta signaling system through the increase of TGFbeta2, TbetaRI, stimulatory Smad 2, and common Smad 4 expression, which occurred concomitantly with a decrease of the inhibitory Smad 6 expression.
Guéripel
Xavier
X
INSERM U-407, Faculté de Médecine Lyon-Sud, 69921 Oullins, France.
Benahmed
Mohamed
M
Gougeon
Alain
A
D030201:Activin Receptors, Type I / Q000235:genetics*; D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics*; D015536:Down-Regulation; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D015870:Gene Expression / Q000502:physiology; D006107:Granulosa Cells / Q000187:drug effects / Q000502:physiology; D007986:Luteinizing Hormone / Q000494:pharmacology*; D051379:Mice; D008815:Mice, Inbred Strains; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger / Q000032:analysis; D000077293:Receptor, Transforming Growth Factor-beta Type I; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics*; D051899:Smad2 Protein; D051900:Smad3 Protein; D051901:Smad4 Protein; D051905:Smad6 Protein; D013799:Theca Cells / Q000187:drug effects / Q000502:physiology; D015534:Trans-Activators / Q000235:genetics*; D016212:Transforming Growth Factor beta / Q000235:genetics*; D053773:Transforming Growth Factor beta1; D053781:Transforming Growth Factor beta2; D015854:Up-Regulation
D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D018125:Receptors, Transforming Growth Factor beta; D051899:Smad2 Protein; C497783:Smad2 protein, mouse; D051900:Smad3 Protein; C497791:Smad3 protein, mouse; D051901:Smad4 Protein; D051905:Smad6 Protein; C497803:Smad6 protein, mouse; C508960:TGFB1 protein, human; C509041:TGFB2 protein, human; C508961:Tgfb1 protein, mouse; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D053781:Transforming Growth Factor beta2; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D017346:Protein Serine-Threonine Kinases; D030201:Activin Receptors, Type I; D000077293:Receptor, Transforming Growth Factor-beta Type I; D000077294:Receptor, Transforming Growth Factor-beta Type II