Sexual dimorphism in embryo responses to maternal regulatory factors

描述（由申请人提供）：植入前胚胎的发育程序很容易通过微环境的改变而改变。由此产生的发展轨迹的变化可以产生长期影响，延伸到出生后的生活。男性和女性胚胎在着床前阶段对环境的改变有不同的反应。最近的数据从我们的实验室与牛胚胎表明，性二型性反应的微环境的变化可以介导的性别特异性反应的母体调控信号。从发育第5-7天开始用集落刺激因子2（CSF 2）处理胚胎，导致胚胎在移植至雌性后的特征发生性别特异性改变，并在妊娠第15天恢复。如果这种两性异形现象是一种普遍现象，就需要进行性别分析，以了解控制发育的基本机制、环境对胚胎发育的影响以及提高妇女生育力的治疗方法。目前的提案旨在确定胚胎发育的调节在多大程度上取决于性别。目前有两个目标：开发用于理解CSF 2如何对胚胎发育发挥性别特异性作用的分子基础的模型，并评估在调节植入前发育中的性二态性现象是否普遍（即，存在多于一种调节分子）。为了实现这些目标，我们将利用我们实验室的大量初步数据，这些数据描述了CSF 2和其他两种子宫调节因子胰岛素样生长因子1（IGF 1）和dickkopf相关蛋白1（DKK 1）如何改变牛囊胚的发育。特别是，我们将测试当使用X或Y分选的精子产生胚胎时，CSF 2，IGF 1和DKK 1对先前观察到的胚胎的作用是否以性别特异性方式发生。对于目标1，将确定牛桑椹胚和囊胚对CSF 2反应的性别差异。将进行四个实验以评价CSF 2在桑椹胚和胚泡中基因表达、细胞凋亡抑制和胚泡内细胞团中细胞数量增加方面对胚胎调控的性二态性。目的2将通过检测IGF 1和DKK 1是否以性别特异性的方式对牛胚胎发挥作用来确定其他调节因子是否存在性二型性。将进行实验，以确定雄性和雌性胚胎在IGF 1对囊胚发育、基因表达和细胞凋亡的作用以及DKK 1对囊胚中细胞分配至上胚层、原始内胚层和滋养外胚层谱系细胞的作用方面的差异。这些实验对于发展研究模型以描述性二型性的建立机制（目标1）和确定性二型性作为胚胎发育调控的重要决定因素的重要性（目标2）是很重要的。

DESCRIPTION (provided by applicant): The developmental program of the preimplantation embryo is readily modified by alterations in the microenvironment. The resultant change in trajectory of development can have long-acting effects that extend into post-natal life. Male and female embryos can respond differently to environmental modification during the preimplantation period. Recent data from our laboratory with bovine embryos indicate that sexual dimorphism in response to changes in the microenvironment could be mediated by gender-specific responses to maternal regulatory signals. Treatment of embryos with colony-stimulating factor 2 (CSF2) from Day 5-7 of development caused gender-specific alterations in characteristics of embryos after transfer to females and recovery at Day 15 of gestation. If this phenomenon of sexual dimorphism is a general one, gender-specific analysis will be required to understand basic mechanisms controlling development, environmental effects on embryonic development, and therapeutic approaches to improving fertility in women. The current proposal seeks to determine the extent to which regulation of embryonic development depends on gender. There are two immediate goals: to develop a model for understanding the molecular basis for how CSF2 exerts gender-specific effects on embryonic development and to evaluate whether the phenomenon of sexual dimorphism in regulation of preimplantation development is widespread (i.e., exists for more than one regulatory molecule). To meet these objectives, we will take advantage of a large amount of preliminary data from our laboratory that describes how CSF2 and two other uterine regulatory factors, insulin-like growth factor 1 (IGF1) and dickkopf-related protein 1 (DKK1), modify development of the bovine blastocyst. In particular, we will test whether actions of CSF2, IGF1 and DKK1 on embryos seen previously occur in a gender-specific manner when embryos are produced using X- or Y-sorted spermatozoa. For Aim 1, gender differences in response of bovine morulae and blastocysts to CSF2 will be determined. Four experiments will be conducted to evaluate sexual dimorphism in regulation of the embryo by CSF2 with respect to gene expression in morulae and blastocysts, inhibition of apoptosis, and increase in numbers of cells in the inner cell mass of the blastocyst. Aim 2 will determine whether sexual dimorphism exists for other regulatory factors by testing whether IGF1 and DKK1 exert actions on bovine embryos in a gender-specific manner. Experiments will be performed to determine differences between male and female embryos with respect to IGF1 actions on blastocyst development, gene expression and apoptosis and with respect to DKK1 actions on allocation of cells in the blastocyst to cells of the epiblast, primitive endoderm, and trophectoderm lineages. These experiments are important to develop research models for delineating mechanisms by which sexual dimorphism is established (Aim 1) and to determine the importance of sexual dimorphism as an important determinant of regulation of embryonic development (Aim 2).