Characterization of the cyclic regulation and physiological functions of BMP antagonists during folliculogenesis

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 561-585-Ovarian & Uterine Function II
Basic/Clinical
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-565
Ting-Yu Lin*
Yang Ming University, Taipei
Bone morphogenetic protein (BMP) molecules are known to signal through common receptors and can be co-expressed at the same stage, even in the same cell type, of the ovary. Therefore, BMP antagonists are proposed to regulate the activity as well as the spatial and temporal expression of these BMPs in the ovary, thus allowing these molecules to function coordinately but not redundantly during folliculogenesis. Based on this, we intended to screen the ovarian expression patterns of BMP antagonists and choose candidates for further revealing their physiological functions in the ovary. Using the ovaries harvested from mature and superovulatory rats, we noticed that the transcript level of twisted gastrulation (Tsg) is higher than that of other BMP antagonists during folliculogenesis. Moreover, the signals of transcript and protein of Tsg were also detected in each main cell type of follicles by real-time quantification and immunohistochemistry, respectively. Because early studies have suggested that Tsg can antagonize the BMP signaling through either direct binding or forming a coordinate complex with chordin or ventroptin, we further examined the profile of direct and synergistic antagonist potency of Tsg against the ovarian-expressed BMP and TGFβ members. We found that Tsg itself inhibits BMP6 and BMP7 effectively. The Tsg and chordin or ventroptin complex can further increase the antagonizing effect on BMP2, 4, and 7 synergistically. In addition, Tsg or Tsg and chordin or ventroptin complex can reverse the suppression influences of BMP6 or BMP7 on FSH-induced progesterone production in cultured granulosa cells. Taken together, our findings suggest that Tsg can partially block the activity of BMP6 and BMP7 through direct interaction or synergistically coordinate with chordin or ventroptin for fine-tuning the diverse ovarian-expressed BMP activities both spatially and temporally.

Nothing to Disclose: TYL

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