Sperm Motility Modulations Crucial to Fertilization

精子活力调节对受精至关重要

• 批准号: 7760210
• 负责人: Susan Stevens Suarez
• 金额: $ 7.06万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-02-01 至 2012-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7760210
• 关键词: Behavior; Biological; CatSper; Cell membrane; Cells; Chemotactic Factors; Chemotaxis; Contraceptive Usage; Contraceptive methods; Couples; Epithelium; Exposure to; Failure; Fertilization; Flagella; Image; In Vitro; Infertility; Mammalian Oviducts; Movement; Mus; Mutant Strains Mice; Nuclear Envelope; Oocytes; Partner in relationship; Pattern; Pilot Projects; Process; Progesterone; Proteomics; Reporting; Research; Side; Signal Pathway; Signal Transduction; Site; Solid; Source; Sperm Head; Sperm Motility; Testing; Time; Transillumination; Work; base; cell motility; egg; in vivo; male; mouse model; ovulation time; pregnant; public health relevance; research study; response; sperm cell

DESCRIPTION (provided by applicant): In order to reach the oocyte and fertilize it, sperm must not only be vigorously motile, but must also modulate flagellar beating patterns appropriately. They must hyperactivate, which involves switching to high-amplitude, asymmetrical beating, as evidenced by the failure to fertilize of CatSper null mutant mouse sperm that cannot hyperactivate. Furthermore, there is evidence that sperm respond to chemotactic factors in order to direct their movement toward the oocyte. Although Ca2+ signaling is involved in both processes, the relationship of hyperactivation to chemotaxis is a mystery. Sperm become hyperactivated in the sperm reservoir in the lower oviduct before the time of ovulation and thus very likely before exposure to chemotactic signals from the egg mass. Our overall working hypothesis is that hyperactivation is modulated to direct sperm toward the oocyte. The objective of this R03 pilot project is to gain solid evidence for modulation of hyperactivation. Aim 1: To determine the flagellar movement patterns of sperm in the oviduct. The relationship of hyperactivation to chemotaxis will be studied for the first time in vivo using transillumination of oviducts of mated mice to analyze the movements of sperm as they escape from the reservoir in the lower oviduct and move toward oocytes. The symmetry and direction of asymmetrical bends will be evaluated. Aim 2: To distinguish the effects of Ca2+ influx through CatSper channels from those of Ca2+ release from redundant nuclear envelope (RNE) stores. CatSper channels are confined to the plasma membrane of the principal piece of the flagellum and the RNE is located at the base of the flagellum. Activation of CatSper channels produces deep pro-hook bends (in the same direction as the hook of the mouse sperm head), whereas stimulation of Ca2+ release from the RNE induces deep anti-hook bends. Switching from deep pro-hook to deep anti-hook bends could serve to adjust the course of sperm toward the oocyte. Ca2+ imaging and proteomic approaches will be used to distinguish the responses of sperm. Aim 3: To test the effects of putative chemotactic signals on behavior of hyperactivated sperm. If evidence is obtained in support of the hypothesis, then we will seek to identify the sources of modulators of sperm motility and further elucidate the cell signaling pathways that modulate sperm motility. Findings should inform efforts to treat infertility and to develop contraceptive methods. PUBLIC HEALTH RELEVANCE: Approximately 7% of US couples reported that they did not get pregnant after a year without contraceptive use. Roughly half of the cases of infertility are attributed to a male factor, particularly low sperm quantity and/or motility. To fertilize, sperm must be able to hyperactivate and also to respond to chemotactic factors to direct their movement toward the egg. Nothing is known about the relationship of hyperactivation to chemotaxis. The objective is to elucidate this relationship, by analyzing behavior of sperm in the oviduct and using cell biological and proteomic approaches to determine how sperm movement is modulated to enable them to reach the egg.

描述（由申请人提供）：为了到达卵母细胞并使其受精，精子不仅必须具有强烈的运动，而且必须适当地调节鞭毛的跳动模式。它们必须过度激活，这涉及到切换到高振幅，不对称跳动，正如不能过度激活的CatSper null突变小鼠精子无法受精所证明的那样。此外，有证据表明，精子对趋化因子作出反应，以指导它们向卵母细胞移动。虽然Ca2+信号参与了这两个过程，但过度激活与趋化的关系是一个谜。在排卵之前，精子在输卵管下部的精子储存库中变得过度活跃，因此很可能在接触到来自卵子团的趋化信号之前。我们的总体工作假设是，过度激活是被调节的，以引导精子流向卵母细胞。这个R03试点项目的目的是为过度激活的调节获得确凿的证据。目的1：确定精子在输卵管中的鞭毛运动模式。我们将首次在体内研究这种过度激活与趋化的关系，通过对交配小鼠的输卵管进行透光照射，分析精子从输卵管下部的储存库中逃逸并向卵母细胞移动的过程。不对称弯曲的对称性和方向将被评估。目的2：区分Ca2+通过CatSper通道内流的影响和Ca2+从冗余核膜（RNE）储存释放的影响。CatSper通道被限制在鞭毛主片的质膜上，RNE位于鞭毛的基部。激活CatSper通道产生深前钩弯曲（与小鼠精子头部的钩方向相同），而刺激RNE释放Ca2+诱导深反钩弯曲。从深的亲钩弯到深的反钩弯的转换可能有助于调整精子向卵母细胞的路线。Ca2+成像和蛋白质组学方法将用于区分精子的反应。目的3：测试趋化信号对过度激活精子行为的影响。如果有证据支持这一假设，那么我们将寻求确定精子运动调节剂的来源，并进一步阐明调节精子运动的细胞信号通路。研究结果应该为治疗不孕症和开发避孕方法提供信息。