scholarly journals Selection of the Dominant Follicle and Insulin-Like Growth Factor (IGF)-Binding Proteins: Evidence that Pregnancy-Associated Plasma Protein A Contributes to Proteolysis of IGF-Binding Protein 5 in Bovine Follicular Fluid

Endocrinology ◽  
2003 ◽  
Vol 144 (2) ◽  
pp. 437-446 ◽  
Author(s):  
G. M. Rivera ◽  
J. E. Fortune
Keyword(s):  
Proteolytic Activity ◽  
Plasma Protein ◽  
Follicular Fluid ◽  
Binding Proteins ◽  
Protein A ◽  
Positive Control ◽  
Dominant Follicle ◽  
Igf Binding Proteins ◽  
Igf Binding ◽  
Igf Binding Protein

Development of a dominant follicle is associated with decreased intrafollicular low molecular weight IGF-binding proteins (namely IGFBP-2, -4, and -5) and increased proteolysis of IGFBP-4 by pregnancy-associated plasma protein A (PAPP-A). In addition to IGFBP-4 proteolytic activity, bovine follicular fluid contains strong proteolytic activity for IGFBP-5, but not for IGFBP-2. Here we show that the IGFBP-5 protease present in bovine follicular fluid is a neutral/basic pH-favoring, Zn2+ metalloprotease very similar to the previously described IGFBP-4 protease. We hypothesized that immunoneutralization and immunoprecipitation with anti-PAPP-A antibodies would result in abrogation of the IGFBP-4, but not the IGFBP-5, proteolytic activity in follicular fluid. As expected, anti-PAPP-A antibodies were able to neutralize and precipitate the IGFBP-4, but not the IGFBP-5, proteolytic activity of human pregnancy serum, which was used as a positive control for PAPP-A. Surprisingly, immunoneutralization and immunoprecipitation of follicular fluid from bovine preovulatory follicles with anti-PAPP-A antibodies abrogated both IGFBP-4 and IGFBP-5 proteolysis. Quantitative results derived from phosphorimaging revealed a complete inhibition of both IGFBP-4 and -5 proteolysis by follicular fluid incubated for 2 or 5 h in the presence of anti-PAPP-A antibodies. After 18 h of incubation, anti-PAPP-A antibodies still inhibited IGFBP-5 degradation, although with an efficiency lower than that for IGFBP-4 degradation. Both proteolytic activities have identical electrophoretic mobility, and a single band (∼400 kDa) was detected by Western immunoblotting of bovine follicular fluid with anti-PAPP-A antibodies. Proteolysis of IGFBP-5 was readily detectable in follicular fluid from dominant follicles and was negligible in subordinate follicles from the same cohort. These results suggest that an active intrafollicular IGFBP-4/-5 proteolytic system, in which PAPP-A is the major protease involved, is an important determinant of follicular fate.

scholarly journals Author Correction: A common variant of the pregnancy-associated plasma protein-A (PAPPA) gene encodes a protein with reduced proteolytic activity towards IGF-binding proteins

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
J. A. Bøtkjær ◽  
P. R. Noer ◽  
Claus Oxvig ◽  
Claus Yding Andersen
Keyword(s):  
Proteolytic Activity ◽  
Plasma Protein ◽  
Binding Proteins ◽  
Protein A ◽  
Common Variant ◽  
Igf Binding Proteins ◽  
Igf Binding

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

scholarly journals Proteolytic degradation of IGF-binding protein (IGFBP)-2 in equine ovarian follicles: involvement of pregnancy-associated plasma protein-A (PAPP-A) and association with dominant but not subordinated follicles

2004 ◽  
Vol 182 (3) ◽  
pp. 457-466 ◽  
Author(s):  
N Gerard ◽  
T Delpuech ◽  
C Oxvig ◽  
MT Overgaard ◽  
P Monget
Keyword(s):  
Proteolytic Activity ◽  
Plasma Protein ◽  
Follicular Fluid ◽  
Protein A ◽  
Binding Domain ◽  
Proteolytic Degradation ◽  
Heparin Binding ◽  
Heparin Binding Domain ◽  
Igf Binding ◽  
Igf Binding Protein

In the ovary of mammalian species, terminal follicular growth is accompanied by a decrease in intrafollicular levels of IGF-binding protein-2 (IGFBP-2) and IGFBP-4. The decrease in IGFBP-4 levels is essentially due to an increase in proteolytic cleavage by intrafollicular pregnancy-associated plasma protein-A (PAPP-A) in growing healthy follicles. The decrease in IGFBP-2 levels is partly due to a decrease in mRNA expression by follicular cells. In addition, we have recently shown that IGFBP-2 is also proteolytically cleaved by PAPP-A in bovine and porcine growing follicles. In the present work, we showed that follicular fluid from late dominant equine follicles (35 mm diameter) contains a proteolytic activity against IGFBP-2. First follicular fluid from dominant follicles contained lower levels of native IGFBP-2 than the corresponding serum, as assessed by Western ligand blotting. In contrast, immunoblotting experiments showed much higher levels of a 12 kDa proteolytic fragment in dominant follicular fluid than in the serum. Moreover, equine dominant follicular fluid was able to induce proteolysis of exogenous recombinant bovine (rb)IGFBP-2, this degradation being dose-dependently enhanced by IGFs. The proteolytic activity against IGFBP-2 in equine follicles was partially immunoneutralized by a polyclonal antibody raised against human PAPP-A. Moreover, cleavage of rbIGFBP-2 by equine follicular fluid was dose-dependently inhibited by a peptide derived from the heparin-binding domain of IGFBP-5, as well as by peptides derived from other heparin-binding domain-containing proteins such as connective tissue growth factor, vitronectin and heparin-interacting protein, previously shown to inhibit PAPP-A. Finally, the proteolytic activity was very low in subordinate follicles, was high in both early (25 mm diameter) and late (35 mm diameter) dominant follicles, and was slightly lower in preovulatory follicles recovered 35 h after human chorionic gonadotropin (hCG) treatment.Overall, these data show that in the equine ovary, the selection of dominant follicles is associated with an increase of the proteolytic degradation of IGFBP-2 by PAPP-A, as for IGFBP-4, and potentially other protease(s), probably contributing to the increase in IGF bioavailability. In atretic subordinate follicles, the decrease in the proteolytic degradation of IGFBP-2, probably due in part to a direct inhibition by peptides containing heparin-binding domains, contributes to the increase in IGFBP-2 levels and the decrease in IGF bioavailability. The expression of PAPP-A and IGFBP-2 mRNA during folliculogenesis remain to be investigated in the mare.

scholarly journals A common variant of the pregnancy-associated plasma protein-A (PAPPA) gene encodes a protein with reduced proteolytic activity towards IGF-binding proteins

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jane Alrø Bøtkjær ◽  
Pernille Rimmer Noer ◽  
Claus Oxvig ◽  
Claus Yding Andersen
Keyword(s):  
Plasma Protein ◽  
Binding Proteins ◽  
Specific Activity ◽  
Protein A ◽  
P Value ◽  
Surface Binding ◽  
Cleavage Rate ◽  
Igf Binding Proteins ◽  
Single Nucleotide ◽  
Igf Binding

Abstract Pregnancy-associated plasma protein-A (PAPP-A) is a key regulator of insulin-like growth factor (IGF) bioactivity, by releasing the IGFs from their corresponding IGF-binding proteins (IGFBPs). The minor allele of the single nucleotide polymorphism (SNP), rs7020782 (serine < tyrosine), in PAPPA has previously been associated with recurrent pregnancy loss as well as with significant reduced levels of PAPP-A protein in human ovarian follicles. The aim of the present study was to reveal a possible functional effect of the rs7020782 SNP in PAPPA by comparing recombinant PAPP-A proteins from transfected human embryonic kidney 293 T cells. The proteolytic cleavage of IGFBP-4 was shown to be affected by the rs7020782 SNP in PAPPA, showing a significantly reduced cleavage rate for the serine variant compared to the tyrosine variant (p-value < 0.001). The serine variant also showed a trend towards reduced cleavage rates, that was not significant, towards IGFBP-2 and IGFBP-5 compared to the tyrosine variant. No differences were found when analysing cell surface binding, complex formation between PAPP-A and STC2 or proMBP, nor when analysing STC1 inhibition of PAPP-A-mediated IGFBP-4 cleavage. Regulation of IGF bioactivity in reproductive tissues is important and the rs7020782 SNP in PAPPA may disturb this regulation by altering the specific activity of PAPP-A.

scholarly journals Insulin-Like Growth Factor Bioactivity, Stanniocalcin-2, Pregnancy-Associated Plasma Protein-A, and IGF-Binding Protein-4 in Pleural Fluid and Serum From Patients With Pulmonary Disease

2017 ◽  
Vol 102 (9) ◽  
pp. 3526-3534 ◽  
Author(s):  
Ulrick Skipper Espelund ◽  
Mette Bjerre ◽  
Rikke Hjortebjerg ◽  
Torben Riis Rasmussen ◽  
Anders Lundby ◽  
...  
Keyword(s):  
Growth Factor ◽  
Pleural Fluid ◽  
Plasma Protein ◽  
Binding Protein ◽  
Protein A ◽  
Insulin Like Growth Factor ◽  
Igf System ◽  
Igf Binding ◽  
Stanniocalcin 2 ◽  
Igf Binding Protein

Abstract Context Members of the insulin-like growth factor (IGF) system are primarily produced in the liver and secreted into the circulation, but they are also produced, recruited, and activated locally in tissues. Objective To compare activity and concentrations of IGF system components in pleural fluid and blood. Design Pathological pleural fluid, secondary to lung cancer or nonmalignant disease, and matching blood samples were collected from 24 patients ages 66.7 to 81.9 years. Methods IGF-related proteins and cytokine levels were measured by immunoassays or immunoblotting. Bioactive IGF was measured by an IGF-1 receptor phosphorylation assay. Results Total IGF-1 concentration did not differ between the compartments, but concentrations of free IGF-1 and bioactive IGF were more than threefold higher in pleural fluid than in corresponding serum samples (P = 0.0004), regardless of etiology. Median pregnancy-associated plasma protein-A (PAPP-A) and interleukin (IL)-6 levels were increased 47-fold and 143-fold, respectively, in pleural fluid compared with plasma (P &lt; 0.0001). PAPP-A and IL-6 concentrations correlated positively (r = 0.46; P = 0.02). In pleural fluid, levels of PAPP-A–generated IGF binding protein-4 fragments correlated inversely with that of stanniocalcin-2 (r ≤ −0.42; P ≤ 0.05), a PAPP-A inhibitor; such correlations were absent in plasma. Conclusion Pathological pleural fluid is characterized by increased in vitro IGF bioactivity and elevated concentrations of PAPP-A, an IGF-activating proteinase. Thus, the tissue activity of the IGF system may differ substantially from that of the circulating IGF system. The correlation between IL-6 and PAPP-A indicates that inflammation plays a role in promoting local tissue IGF activity.

Depot-specific and GH-dependent regulation of IGF binding protein-4, pregnancy-associated plasma protein-A, and stanniocalcin-2 in murine adipose tissue

2018 ◽  
Vol 39 ◽  
pp. 54-61 ◽  
Author(s):  
Rikke Hjortebjerg ◽  
Darlene E. Berryman ◽  
Ross Comisford ◽  
Edward O. List ◽  
Claus Oxvig ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Plasma Protein ◽  
Binding Protein ◽  
Protein A ◽  
Igf Binding ◽  
Stanniocalcin 2 ◽  
Igf Binding Protein

Relationships between concentrations of steroids, igf-1 and igf binding proteins during follicular development in the ewe

1995 ◽  
Vol 1995 ◽  
pp. 56-56
Author(s):  
M. Khalid ◽  
W. Haresign
Keyword(s):  
Follicular Fluid ◽  
Biochemical Markers ◽  
Binding Proteins ◽  
Ovarian Function ◽  
Follicular Development ◽  
Physiological Status ◽  
Igf Binding Proteins ◽  
Ovarian Cells ◽  
Igf Binding

Insulin-like growth factor-1 (IGF-1) is one of the potential autocrine/paracrine regulators of ovarian function. Not only do relationships exist between follicular fluid concentrations of IGF-1 and various biochemical markers of follicular differentiation, but IGF-1 has also been shown to stimulate both proliferation and steroidogenesis in ovarian cells in vitro (Adashi et al., 1985). The actions of IGF-1 are thought to be modulated by IGF-binding proteins (IGFBPs). Indeed, follicular growth and atresia in the ewe have been reported to be determined more by changes in IGFBPs than by changes in IGF-1 (Monget et al., 1993). However, in mat particular study, stage of follicular development was determined by follicle size and by microscopic examination of the granulosa cells of individual follicles rather than by biochemical markers of follicle status. The objective of the present study was, therefore, to investigate changes in IGF-1 and IGFBPs levels in follicular fluid and to relate these to the physiological status as determined by steroidogenic content of follicular fluid.

scholarly journals Analysis of Pregnancy-Associated Plasma Protein A Production in Human Adult Cardiac Progenitor Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Piera D’Elia ◽  
Vittoria Ionta ◽  
Isotta Chimenti ◽  
Francesco Angelini ◽  
Fabio Miraldi ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Plasma Protein ◽  
Protein A ◽  
Therapeutic Effects ◽  
Cardiac Progenitor Cells ◽  
Cardiac Cell ◽  
Igf Binding Proteins ◽  
Human Adult ◽  
Igf Binding ◽  
Cardiac Cell Therapy

IGF-binding proteins (IGFBPs) and their proteases regulate IGFs bioavailability in multiple tissues. Pregnancy-associated plasma protein A (PAPP-A) is a protease acting by cleaving IGFBP2, 4, and 5, regulating local bioavailability of IGFs. We have previously shown that IGFs and IGFBPs are produced by human adult cardiac progenitor cells (haCPCs) and that IGF-1 exerts paracrine therapeutic effects in cardiac cell therapy with CPCs. Using immunofluorescence and enzyme immunoassays, we firstly report that PAPP-A is produced and secreted in surprisingly high amounts by haCPCs. In particular, the homodimeric, enzymatically active, PAPP-A is secreted in relevant concentrations in haCPC-conditioned media, while the enzymatically inactive PAPPA/proMBP complex is not detectable in the same media. Furthermore, we show that both homodimeric PAPP-A and proMBP can be detected as cell associated, suggesting that the previously described complex formation at the cell surface does not occur easily, thus positively affecting IGF signalling. Therefore, our results strongly support the importance of PAPP-A for the IGFs/IGFBPs/PAPP-A axis in CPCs biology.

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