Sexual dimorphism in embryo responses to maternal regulatory factors

描述（由申请人提供）：着床前胚胎的发育程序很容易因微环境的改变而改变。由此导致的发育轨迹的改变可能会产生长期影响，并延续到出生后的生活。在着床前，男性和女性胚胎对环境变化的反应不同。最近来自我们实验室的牛胚胎数据表明，对微环境变化的性二态性反应可能是通过对母体调节信号的性别特异性反应来介导的。胚胎在发育第5-7天用集落刺激因子2 （CSF2）处理后，胚胎在移植给雌性和妊娠第15天恢复后的特征发生了性别特异性改变。如果这种两性异形现象是一种普遍现象，就需要进行针对性别的分析，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能力的治疗方法。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。有两个直接的目标：建立一个模型来理解CSF2如何对胚胎发育施加性别特异性影响的分子基础，并评估在着床前发育的调节中性别二态现象是否普遍存在（即存在多个调节分子）。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，描述CSF2和其他两个子宫调节因子，胰岛素样生长因子1 （IGF1）和dickkopf相关蛋白1 （DKK1）如何改变牛囊胚的发育。特别是，我们将测试CSF2， IGF1和DKK1对胚胎的作用是否以性别特异性的方式发生，当胚胎使用X或y分类的精子产生时。在Aim 1中，将确定牛桑葚胚和囊胚对CSF2反应的性别差异。我们将进行四项实验来评估两性二态性在CSF2对胚泡和胚泡基因表达、细胞凋亡抑制和胚泡内细胞团细胞数量增加方面的调控作用。目的2将通过测试IGF1和DKK1是否以性别特异性的方式作用于牛胚胎来确定其他调节因子是否存在性别二态性。研究人员将进行实验，以确定男性和女性胚胎在IGF1对囊胚发育、基因表达和凋亡的作用以及DKK1对囊胚细胞向外胚层、原始内胚层和滋养外胚层细胞分配的作用方面的差异。这些实验对于建立描述两性二态性建立机制的研究模型（目的1）和确定两性二态性作为胚胎发育调节的重要决定因素的重要性（目的2）非常重要。

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).