Submission Number: PHI-4-10-10
Abstract Number: 152
INVOLVEMENT OF PREGNANCY ASSOCIATED PLASMA PROTEIN-A IN INSULIN-LIKE GROWTH FACTOR-BINDING PROTEIN-4 PROTEOLYTIC DEGRADATION IN OVINE, BOVINE, PORCINE AND EQUINE PREOVULATORY FOLLICLES.
Sabine Mazerbourg 1, Cheryl Conover 2, Claus Oxvig 3, Michael Overgaard 3, Martine Olivi 4, Michel Vidaud 4, Jurgen Zapf 5 and Philippe Monget 1
INRA, PRMD, Nouzilly, France 1
Mayo Clinic, Rochester, MN 2
Statens Serum Institut, Copenhagen, Denmark 3
Faculté de Pharmacie de Port-Royal, Paris, France 4
University Hospital, Zürich, Switzerland 5
Abstract:
In mammals, follicular growth and atresia are characterized by an increase and a decrease in Insulin-like Growth Factor-Binding Protein (IGFBP)-4 proteolytic degradation. In woman ovary, intrafollicular IGFBP-4 protease was recently identified as Pregnancy Associated Plasma Protein-A (PAPP-A). In the present study, several lines of evidence suggest that PAPP-A is the intrafollicular IGFBP-4 protease in ovine, bovine, porcine and equine ovaries as well. First, in these four species, PAPPA is detected by ELISA in follicular fluid from preovulatory follicles. Secondly polyclonal antibodies against human PAPP-A are able to immunoneutralize and to immunodeplete intrafollicular IGFBP-4 degradation. Thirdly, we have recently shown that IGFBP-4 degradation after incubation with follicular fluid was abolished by peptides containing heparin-binding domains (HBD) from IGFBP-3, -5, Vitronectin, Heparan-Interacting Protein (HIP). In the present work, HBD-peptides are also able to inhibit IGFBP-4 degradation by pure recombinant PAPP-A. Moreover, real-time quantitative RT-PCR show that expression of PAPP-A mRNA increases during terminal follicular growth. Overall these data suggest that as in woman, PAPP-A is responsible for proteolytic degradation of IGFBP-4 in preovulatory follicles from domestic animal species. .
Keywords: Ovary, IGFBP-4, Protease, PAPP-A, domestic animals
This abstract is being presented at: 8:00 AM in session:
Follicular Development I