Expression of protease nexin-1 and plasminogen activators during follicular growth and the periovulatory period in cattle.
Extracellular matrix remodeling occurs during ovarian follicular development, mediated by plasminogen activators (PAs) and PA inhibitors including protease nexin-1 (PN-1). In the present study we measured expression/activity of the PA system in bovine follicles at different stages of development by timed collection of ovaries during the first follicular wave and during the periovulatory period, and in follicles collected from an abattoir. The abundance of mRNA encoding PN-1, tissue-type PA (tPA), urokinase (uPA) and PA inhibitor-1 (PAI-1) were initially upregulated by human chorionic gonadotropin (hCG) in bovine preovulatory follicular wall homogenates. PN-1, PAI-1 and tPA mRNA expression then decreased near the expected time of ovulation, whereas uPA mRNA levels remained high. PN-1 concentration in follicular fluid (FF) decreased and reached the lowest level at the time of ovulation, whereas plasmin activity in FF increased significantly after hCG. Follicles collected from the abattoir were classified as non-atretic, early-atretic or atretic based on FF estradiol and progesterone content: PN-1 protein levels in FF were significantly higher in non-atretic than in atretic follicles, and plasmin activity was correspondingly higher in the atretic follicles. No changes in PN-1 levels in FF were observed during the growth of pre-deviation follicles early in a follicular wave. These results indicate that PN-1 may be involved in the process of atresia in non-ovulatory dominant follicles and the prevention of precocious proteolysis in periovulatory follicles.
Cao
Mingju
M
Centre de Recherche en Reproduction Animale, CRRA, Faculté de Médecine Vétérinaire, Université de Montréal, C.P. 5000 St-Hyacinthe, Québec, Canada.
Buratini
José
J
Lussier
Jacques G
JG
Carrière
Paul D
PD
Price
Christopher A
CA
D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002417:Cattle / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005496:Follicular Atresia / Q000378:metabolism*; D006080:Ovarian Follicle / Q000378:metabolism / Q000502:physiology*; D010060:Ovulation / Q000502:physiology*; D017395:Plasminogen Activator Inhibitor 1 / Q000032:analysis / Q000235:genetics; D010960:Plasminogen Activators / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D058255:Protease Nexins; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D058258:Serpin E2; D046509:Tissue Culture Techniques; D010959:Tissue Plasminogen Activator / Q000032:analysis / Q000235:genetics; D014568:Urokinase-Type Plasminogen Activator / Q000032:analysis / Q000235:genetics
D016564:Amyloid beta-Protein Precursor; D017395:Plasminogen Activator Inhibitor 1; D058255:Protease Nexins; D011956:Receptors, Cell Surface; C545486:SERPINE2 protein, human; D058258:Serpin E2; D010960:Plasminogen Activators; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator