M-CSF介导LH诱导的卵母细胞减数分裂和排卵及信号传导通路研究

Studies on the mechanism of ovulation have confirmed that inhibitions of natriuretic peptide precursor type C (NPPC) and natriuretic peptide receptor 2 (NPR2) are essential for LH-induced ovulation. LH inhibits NPPC/NPR2, activating oocyte meiosis and inducing ovulation. Recent studies have revealed that granulosa cells release a large amount of M-CSF when LH peaked during ovulation, which suggested that besides NPPC there may be also other molecules as upstream signals to NPR2. Our previous study confirmed that M-CSF inhibited NPPC/NPR2 pathway, suggesting that M-CSF may be involved in ovulation process. Therefore, we propose a research hypothesis that M-CSF/M-CSF-R pathway may mediate the down-regulation of NPPC/NPR2, leading to activation of oocyte meiosis and induction of ovulation by LH signal. In this project the normal C57BL/6 and M-CSF knock-out mice will be used as animal model. In order to verify the above hypothesis we intend to investigate the changes of M-CSF/M-CSF-R in mouse granulosa cells under the effect of LH, to study the effect of M-CSF on NPPC/NPR2, oocyte meiosis as well as ovulation, and to clarify the related signal transduction pathway.

对排卵机制的研究已证实，卵泡颗粒细胞NPPC/NPR2的下调是LH诱发排卵的关键步骤，LH通过下调配体NPPC和受体NPR2，激活卵母细胞减数分裂诱发排卵。最新研究提示，受体NPR2上游很可能存在除配体NPPC之外的其他信号调控分子。项目组预实验证实颗粒细胞内的M-CSF可下调NPPC/NPR2，结合文献报道排卵前的LH峰能使卵泡颗粒细胞大量释放M-CSF，我们推测M-CSF可能作为NPPC/NPR2的上游分子参与LH峰诱发排卵过程。根据以上研究结果，我们提出LH经M-CSF及其受体下调NPPC/NPR2激活卵母细胞减数分裂诱发排卵的假设。本项目拟用分子生物学技术，以正常的C57BL/6小鼠、M-CSF基因敲除小鼠和NPPC/NPR2双基因条件敲除小鼠为研究对象，研究M-CSF对卵巢壁层/卵丘颗粒细胞NPPC/NPR2的调控，以及对卵母细胞减数分裂和排卵的影响，从而验证LH通过M-CSF介导诱发排卵的假设。