title: Role of the hyaluronan receptor CD44 during porcine oocyte maturation.
abstract: Previous our studies have shown that CD44, the principal receptor for hyaluronan, is present on cumulus cells during oocyte maturation. Although hyaluronan-CD44 interaction has been implicated in cumulus expansion and/or oocyte maturation, the full significance of CD44 remains unknown. The objective of the present study was to further investigate the role of CD44 in cumulus expansion and oocyte maturation in pigs. We demonstrate here in that CD44 has a key role in oocyte maturation but not in cumulus expansion. Previous studies have reported the physiological significance of cumulus expansion in oocyte maturation. However, our results suggest that cumulus expansion is a necessary condition for oocyte maturation, but that it is not sufficient on its own. Furthermore, western blot analysis demonstrated that the CD44 of the in vitro-matured cumulus-oocyte complexes (COCs) had a larger molecular weight and more terminal sialic acid, which has been proven to inhibit the hyaluronan-binding ability of the receptor, than the CD44 of the in vivo-matured COCs, indicating that the hyaluronan-CD44 interactions during in vitro maturation might be insufficient compared with those in vivo. The insufficient interactions of hyaluronan-CD44 during in vitro maturation may cause the inferior capacity of fertilization and development of oocytes matured in vitro.
authors.affiliation: Laboratory of Animal Reproduction, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Yokoo
authors.forename: Takashi
authors.initials: T
authors.lastname: Shimizu
authors.forename: Naoko
authors.initials: N
authors.lastname: Kimura
authors.forename: Woro Anindito Sri
authors.initials: WA
authors.lastname: Tunjung
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Matsumoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Abe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sasada
authors.forename: Heriberto
authors.initials: H
authors.lastname: Rodriguez-Martinez
authors.forename: Eimei
authors.initials: E
authors.lastname: Sato
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D005260:Female; D018960:Hyaluronan Receptors / Q000378:metabolism*; D008297:Male; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D009865:Oocytes / Q000737:chemistry / Q000166:cytology / Q000502:physiology*; D006080:Ovarian Follicle / Q000254:growth & development; D034421:Sus scrofa
chemical_list: D018960:Hyaluronan Receptors; D019158:N-Acetylneuraminic Acid