卵泡微环境中胶原受体DDR2调控卵泡发育及排卵的作用与机制研究

Follicular development and ovulation disorders account for excessively a quarter of female infertility, the reasons for which are sophisticated to account for. Recent years, the regulation of the micro-environment composed by extra-cellular matrix has been paid significant attention to follicular development and ovulation. It is covered that, as a fibrillar collagen receptor, Discoidin Domain Receptor 2 (DDR2), widely expressed in ovary interstitial, has a cyclic variation and becomes notably higher in the follicular development and ovulation. Ddr2-/- mice have ovulation obstacle and present outstandingly lower reactivity to gonadotropins, however, the mechanism is unknown. It is found in our study that DDR2 is highly expressed in theca cells and granulosa cells. The thecal of Ddr2-/- mice is thin with far lower LHR, androgen, estrogen and progesterone and the cell proliferation is inhibited, which hypothetically contribute to the follicular development and ovulation obstacle resulting from inhibition of the expression of LHR and both thecal differentiation and granular cell proliferation. Employing clinic samples, Ddr2-/- mice, and 3D culture of follicle as well as molecular biology technology, this project intends to research on the function and mechanism of collagen regulating theca cells and granular cells by DDR2 to affect follicular and ovulation, in particular, on the mechanism of DDR2 regulating LHR expression, and to reveal new function and mechanism of DDR2 and collagen in ovarian micro-environment, so as to supply reference to the diagnosis and treatment of infertility caused by poor ovarian Response.

卵泡发育及排卵障碍占女性不孕不育的1/4强，其原因非常复杂；近年，细胞外基质微环境在卵泡发育及排卵中的重要调控作用备受关注。据报道，胶原盘状结构域受体2(DDR2)在卵泡发育及排卵期显著增高，呈周期性变化，Ddr2-/-小鼠排卵障碍，且对促性腺激素不敏感，但详细作用机制尚不清楚。我们研究发现，DDR2高表达于卵泡膜细胞和增殖的颗粒细胞，而Ddr2-/-小鼠卵泡膜则变薄，LHR、雄、雌、孕激素等显著降低，提示LHR及性激素降低可能影响膜细胞分化成熟和颗粒细胞的功能，进而导致卵泡发育及排卵障碍。因此，本项目拟利用临床标本、Ddr2-/-小鼠、卵泡3D培养及分子生物学技术，研究基质胶原激活卵泡体细胞DDR2调控卵泡发育及排卵的作用与机制，重点关注DDR2调控LHR的产生机制，揭示卵巢内细胞外基质胶原及DDR2的新功能，为临床卵巢低反应性不孕症的诊断和治疗提供新思路和新靶点。

本项目利用Ddr2 全身性缺失小鼠及Ddr2 颗粒细胞条件性敲除小鼠，小分子抑制剂等通过功能学、形态学、细胞生物学及分子生物学方法，深入研究了DDR2参与卵泡发育影响卵泡优势选择及排卵的作用及机制。首先，本项目在动物水平阐明了DDR2 影响卵泡发育及排卵的环节及作用，并检测了临床卵巢低反应性排卵障碍患者不同大小卵泡中DDR2的表达，阐明了卵泡微环境中 DDR2 在卵泡发育及排卵期的表达及作用。其次，利用基因干涉和过表达技术，在细胞（2D）水平研究了DDR2 对小鼠卵泡膜细胞、颗粒细胞增殖、分化及激素分泌的影响；阐明了膜细胞及颗粒细胞的DDR2 影响卵泡发育的作用与机制，阐明了DDR2 调控膜细胞、颗粒细胞功能的机制；并通过颗粒细胞条件性敲除小鼠证实颗粒细胞上的DDR2在卵泡发育和排卵阶段扮演关键角色；最后，利用分子生物学技术研究DDR2缺失调控颗粒细胞增殖和VEGF分泌的分子机制，最终揭示 DDR2 调控卵泡发育及排卵的作用与机制。 本研究对卵巢微环境中细胞外基质胶原受体DDR2的作用提出了新认识，排卵障碍性不孕症的诊断治疗及避孕药的研发提供了新靶点。