| Author |
Kuwabara, Yoshimitsu Katayama, Akira Tomiyama, Ryoko Piao, Hu Kurihara, Sachiko Ono, Shuichi Mine, Katsuya Akira, Shigeo Orimo, Hideo Takeshita, Toshiyuki |
| Description |
Country affiliation: Japan Author Affiliation: Kuwabara Y ( Departments of Obstetrics and GynecologyBiochemistry and Molecular BiologyNippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan kuwa@nms.ac.jp.); Katayama A ( Departments of Obstetrics and GynecologyBiochemistry and Molecular BiologyNippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.); Tomiyama R ( Departments of Obstetrics and GynecologyBiochemistry and Molecular BiologyNippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.); Piao H ( Departments of Obstetrics and GynecologyBiochemistry and Molecular BiologyNippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.); Kurihara S ( Departments of Obstetrics and GynecologyBiochemistry and Molecular BiologyNippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan Departments of Obstetrics and GynecologyBiochemistry and Molecular BiologyNippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.); Ono S ( Departments of Obstetrics and GynecologyBiochemistry and Molecular BiologyNippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.); Mine K ( Departments of Obstetrics and GynecologyBiochemistry and Molecular BiologyNippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.); Akira S ( Departments of Obstetrics and GynecologyBiochemistry and Molecular BiologyNippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.); Orimo H ( Departments of Obstetrics and GynecologyBiochemistry and Molecular BiologyNippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.); Takeshita T ( Departments of Obstetrics and GynecologyBiochemistry and Molecular BiologyNippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.) |
| Abstract |
Osteopontin (OPN), a secreted glycoprotein, has multiple physiological functions. This study investigated the regulation and roles of OPN in the mouse ovary during the periovulatory stages. Immature female mice were treated with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) to simulate follicle maturation and ovulation. In situ hybridization and real-time RT-PCR were performed to assess expression of Opn in the periovulatory ovary. Granulosa cells (GCs) from PMSG-primed immature mice were cultured with or without hCG in the presence or absence of OPN, and effects on expression of Opn, progesterone synthesis, and vascular endothelial growth factor (VEGF) signaling were assessed by real-time RT-PCR, ELISA, and western blotting analysis. Opn transcripts were significantly upregulated 3âh after hCG treatment, followed by a peak at 16âh, and the transcripts localized to GCs. Incubation with hCG significantly increased quantities of Opn transcripts in GCs and OPN levels in the culture medium at 12 and 24âh. Furthermore, OPN treatment caused a significant increase in the levels of Star protein, P 450 cholesterol side-chain cleavage enzyme (p450scc), 3-beta-hydroxysteroid dehydrogenase (Hsd3b), and progesterone in the culture medium. OPN treatment promoted Vegf expression in GCs, which was significantly suppressed by a phosphoinositide 3-kinase (PI3K) inhibitor. In addition, OPN treatment stimulated phosphorylation of AKT, a downstream PI3K signaling molecule. In conclusion, expression of Opn was upregulated in mouse ovarian GCs in response to a gonadotropin surge through epidermal growth factor receptor signaling, which enhances progesterone synthesis and Vegf expression during the early-luteal phase. |
