Beyond spermatogenesis: Additional roles of seminal fluid fatty acids in male fertility and age-related reproductive success

项目摘要/摘要 在许多动物中，精液在雄性生殖成功中起着重要作用。精液中的蛋白质 对雄性和雌性生殖生理的多个特征有显著影响。然而，相对较少的 已知精液的第二个主要成分，脂类，除了作为精子膜的作用 选民。这项提案的总体目标是：1)确定脂肪组学和转录组学上的差异 青年和老年男性的精液谱；以及ii)直接测试如何操纵精液的脂质谱 体液会影响男性的生殖成功。这项提议将解决这样的假设，即精液脂质体 影响男性生育力并随年龄变化，从而导致与衰老相关的生殖能力下降 成功。这一假设得到了申请者发表的研究的支持，研究表明脂肪酸和相关的 雄性果蝇精液中的脂质是雄性生育所必需的。两种转座子介导的基因敲除 和RNAi敲除男性射精球(EB)中的一种关键脂肪酸生物合成酶，这是一种 不参与精子发生，导致男性生育力显著下降，有力地支持了 精液脂肪酸对男性生殖成功的贡献。与哺乳动物模型相比，使用 果蝇允许在EB中产生的精液脂质被操纵而不干扰 睾丸内的精子发生。结合脂肪组学和转录组学的强大基因操作 分析将用于实现以下目标：提案的目标1将检验假设的预测 精液脂肪酸和其他脂质成分的变化伴随着衰老相关的 生育能力。使用多种质谱学方法，精液脂质体将被鉴定为年轻和 老年男性，以确定与高生育率和低生育率相关的血脂特征。AIM 2将测试一个 假设的第二个预测，即脂肪酸合成基因在EB中的表达在衰老过程中发生变化 男性，导致精液中脂肪酸和相关脂肪成分的变化。转录本分析 来自年轻和老年男性的EB，随后通过基因敲除进行功能验证，将识别基因 这是精液中脂质含量随年龄变化的基础。在目标3中，对该假设的直接检验将是 通过评估男性生育能力在基因操作精液时是提高还是下降来执行的 液体脂肪酸含量。预期结果意义重大，因为它们可能会发现新的 调节男性和女性生殖生理的机制，并可能指向以前未被认识的 特发性男性不育的原因。这项拟议的研究具有创新性，因为它有望确定一种新的 一类可用于改善不孕症诊断的分子和新的生化途径， 加强辅助生殖技术，治疗老龄化引起的生育率下降。

Project Summary/Abstract In many animals, the seminal fluid plays a major role in male reproductive success. Proteins in the seminal fluid have significant effects on multiple features of male and female reproductive physiology. However, relatively little is known about a second major component of seminal fluid, lipids, beyond their roles as sperm membrane constituents. The overall objectives in this proposal are to i) identify differences in the lipidomic and transcriptomic profiles of seminal fluid in young and aged males; and ii) directly test how manipulating the lipid profile of seminal fluid impacts male reproductive success. This proposal will address the hypothesis that the seminal fluid lipidome influences male fertility and changes with age, thus contributing to the decline of aging-related reproductive success. This hypothesis is supported by the applicants’ published studies showing that fatty acids and related lipids in the seminal fluid of Drosophila males are essential for male fertility. Both transposon-mediated knockout and RNAi knockdown of a key fatty acid biosynthesis enzyme in the male ejaculatory bulb (EB), an organ that is not involved in spermatogenesis, causes a significant decrease in male fertility, strongly supporting the contribution of seminal fluid fatty acids to male reproductive success. In contrast to mammalian models, use of Drosophila allows seminal fluid lipids produced in the EB to be manipulated without interfering with spermatogenesis in the testes. Powerful genetic manipulation in combination with lipidomic and transcriptomic analysis will be used to pursue the following aims: Aim 1 of the proposal will test a prediction of the hypothesis that changes in the composition of seminal fluid fatty acids and other lipids accompany aging-related loss of fertility. Using multiple mass spectrometry methods, the seminal fluid lipidome will be characterized in young and old males in order to identify features of the lipid profile that correlate with high and low fertility. Aim 2 will test a second prediction of the hypothesis, that the expression of fatty acid synthesis genes in the EB changes in aging males, leading to a shift in fatty acid and related lipid composition in the seminal fluid. Transcriptomic analysis of the EB from young and old males followed by functional validation with genetic knockdown will identify genes that underlie age-related changes in seminal fluid lipid content. In Aim 3, a direct test of the hypothesis will be performed by assessing whether male fertility improves or declines upon genetic manipulation of the seminal fluid fatty acid content. The expected outcomes are significant because they are likely to identify new mechanisms that modulate male and female reproductive physiology and may point to previously unrecognized causes of idiopathic male infertility. The proposed study is innovative because it is expected to identify a new class of molecules and novel biochemical pathways that could be used to improve the diagnosis of infertility, enhance assisted reproductive technology, and treat aging-related decline in fertility.