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Hampered cumulus expansion of porcine cumulus-oocyte complexes by excessive presence of alpha2-macroglobulin is likely mediated via inhibition of zinc-dependent metalloproteases

(2017) ANIMAL SCIENCE JOURNAL. 88(9). p.1279-1290
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Abstract
In vitro maturation (IVM) in serum causes hampered expansion of porcine cumulus-oocyte complexes (COCs) due to excessive alpha2-macroglobulin (A2M). This study investigated two hypotheses that could explain the effect of A2M: (i) binding of epider- mal growth factor (EGF) to A2M, followed by its decreased availability; and (ii) inhibition of zinc-dependent metalloproteases. Cumulus expansion was evaluated based on the diameter of the COCs, the proportion of COCs participating in a floating cloud and the proportion of COCs with loss of cumulus cells. The first hypothesis of decreased EGF availability was tested by increasing the EGF concentration (20 and 50 ng/mL vs. 10 ng/mL), but was not confirmed because cumulus expansion did not improve. To verify the second hypothesis of inhibited zinc-dependent metalloproteases, the effect of tissue inhibitor of metalloproteases-3 (TIMP-3) on cumulus expansion during IVM with and without A2M was investigated. To immuno-neutralize A2M, serum was pre-incubated with A2M antibodies. Impaired cumulus expansion because of TIMP-3 could only be observed during IVM in 10% of serum with A2M antibodies. No effect of TIMP-3 was observed in medium without A2M antibodies. These results indicate that A2M and TIMP-3 share a common target, a zinc-dependent metalloprotease. Future research is directed toward the identification of the protease involved.
Keywords
alpha2-macroglobulin, cumulus expansion, in vitro maturation, porcine, serum, IN-VITRO MATURATION, EPIDERMAL-GROWTH-FACTOR, SUCCESSFUL PIGLET PRODUCTION, DEVELOPMENTAL COMPETENCE, CYTOPLASMIC MATURATION, FOLLICULAR-FLUID, MEIOTIC MATURATION, EMBRYO DEVELOPMENT, POLYSPERMIC FERTILIZATION, DENUDED OOCYTES

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Citation

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Chicago
Appeltant, Ruth, Josine Beek, Dominiek Maes, Jo Bijttebier, Katleen Van Steendam, Hans Nauwynck, and Ann Van Soom. 2017. “Hampered Cumulus Expansion of Porcine Cumulus-oocyte Complexes by Excessive Presence of Alpha2-macroglobulin Is Likely Mediated via Inhibition of Zinc-dependent Metalloproteases.” Animal Science Journal 88 (9): 1279–1290.
APA
Appeltant, R., Beek, J., Maes, D., Bijttebier, J., Van Steendam, K., Nauwynck, H., & Van Soom, A. (2017). Hampered cumulus expansion of porcine cumulus-oocyte complexes by excessive presence of alpha2-macroglobulin is likely mediated via inhibition of zinc-dependent metalloproteases. ANIMAL SCIENCE JOURNAL, 88(9), 1279–1290.
Vancouver
1.
Appeltant R, Beek J, Maes D, Bijttebier J, Van Steendam K, Nauwynck H, et al. Hampered cumulus expansion of porcine cumulus-oocyte complexes by excessive presence of alpha2-macroglobulin is likely mediated via inhibition of zinc-dependent metalloproteases. ANIMAL SCIENCE JOURNAL. 2017;88(9):1279–90.
MLA
Appeltant, Ruth, Josine Beek, Dominiek Maes, et al. “Hampered Cumulus Expansion of Porcine Cumulus-oocyte Complexes by Excessive Presence of Alpha2-macroglobulin Is Likely Mediated via Inhibition of Zinc-dependent Metalloproteases.” ANIMAL SCIENCE JOURNAL 88.9 (2017): 1279–1290. Print.
@article{8512419,
  abstract     = {In vitro maturation (IVM) in serum causes hampered expansion of porcine cumulus-oocyte complexes (COCs) due to excessive alpha2-macroglobulin (A2M). This study investigated two hypotheses that could explain the effect of A2M: (i) binding of epider- mal growth factor (EGF) to A2M, followed by its decreased availability; and (ii) inhibition of zinc-dependent metalloproteases. Cumulus expansion was evaluated based on the diameter of the COCs, the proportion of COCs participating in a floating cloud and the proportion of COCs with loss of cumulus cells. The first hypothesis of decreased EGF availability was tested by increasing the EGF concentration (20 and 50 ng/mL vs. 10 ng/mL), but was not confirmed because cumulus expansion did not improve. To verify the second hypothesis of inhibited zinc-dependent metalloproteases, the effect of tissue inhibitor of metalloproteases-3 (TIMP-3) on cumulus expansion during IVM with and without A2M was investigated. To immuno-neutralize A2M, serum was pre-incubated with A2M antibodies. Impaired cumulus expansion because of TIMP-3 could only be observed during IVM in 10\% of serum with A2M antibodies. No effect of TIMP-3 was observed in medium without A2M antibodies. These results indicate that A2M and TIMP-3 share a common target, a zinc-dependent metalloprotease. Future research is directed toward the identification of the protease involved.},
  author       = {Appeltant, Ruth and Beek, Josine and Maes, Dominiek and Bijttebier, Jo and Van Steendam, Katleen and Nauwynck, Hans and Van Soom, Ann},
  issn         = {1344-3941},
  journal      = {ANIMAL SCIENCE JOURNAL},
  language     = {eng},
  number       = {9},
  pages        = {1279--1290},
  title        = {Hampered cumulus expansion of porcine cumulus-oocyte complexes by excessive presence of alpha2-macroglobulin is likely mediated via inhibition of zinc-dependent metalloproteases},
  url          = {http://dx.doi.org/10.1111/asj.12767},
  volume       = {88},
  year         = {2017},
}

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